HandoutProduct Knowledge & Maintenance D8R [PDF]

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PRODUCT KNOWLEDGE & MAINTENANCE D8R



REVISI : 02



PT. MADHANI TALATAH NUSANTARA OPERATIONAL TRAINING DEPARTMENT 2015



PENDAHULUAN



i



KATA PENGANTAR



Dengan rasa syukur kehadirat Tuhan Yang Maha Esa yang telah memberikan kesempatan dan kemampuan kepada kami, sehingga buku pegangan mechanic untuk structure dan fungsi D8R bisa tersusun.



Harapan kami semoga buku ini bisa bermanfaat bagi mechanic dalam mengikuti training structure dan fungsi dan memudahkan dalam memahami cara perawatan unit yang benar sesuai dengan prosedur serta peraturan keselamatan kerja. Dengan demikian bisa diaplikasikan dengan baik setelah berada di lapangan nanti.



Seperti pepatah mengatakan,”Tiada Gading Yang Tak Retak”, dengan kerendahan hati maka kami menyadari bahwa buku ini masih kurang sempurna. Untuk itu kami sangat mengharapkan saran dan kritik yang membangun dari pembaca, demi kesempurnaan buku pegangan mechanic di waktu yang akan datang.



November 2015



Training Departement Penyusun



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



PENDAHULUAN



ii



TRAINING PROFILE Training Tittle  Structure and fungtion D8R Training prerequisites  Sebagai persyaratan untuk mengikuti training structure dan fungtion D8R adalah mekanik PT. MADHANI TALATAH NUSANTARA yang telah mengikuti dan Lulus BMC. Supplementary training manual Untuk kelancaran proses pemahaman system unit D8R, diperlukan sarana penunjang dari factory, sbb :  Product Training Bulletin "Differential Steer Principles--Track-type Tractors" TECB1042  STMG 699 "D8R Track-type Tractor" SESV1699  STMG 633 "D8N Track-type Tractor--Two Pump Hydraulic System" SESV1633 Training duration  40 Hours –4 Days  90 % Inclass - Discussion  10 % Practice Training Outcome Setelah mengikuti training dan dinyatakan lulus, peserta harus mampu :  Mengenali komponen dan lokasi pada semua major komponen.  Mengenali komponen dan lokasi pada semua filter, dipsticks, fill tubes, dan test point  Mengenali komponen dan lokasi pada engine 3408 dan engine 3408E HEUI.  Mampu menjelaskan prinsip kerja setiap komponen pada power train system.  Mampu menelusuri aliran oli pada power train system.  Mampu menjelaskan prinsip kerja setiap komponen pada steering hydraulic system.  Mampu menelusuri aliran oli pada steering hydraulic system.  Mampu menjelaskan prinsip kerja setiap komponen pada implement hydraulic system.  Mampu menelusuri aliran oli pada implement hydraulic system.  Mengenali komponen dan lokasi pada semua major komponen pada Caterpillar Monitoring System. Training passed  Peserta dinyatakan lulus jika :  Nilai post test – Min . 75  Nilai praktek – Min. C Recommended training  Jika berhasil lulus dari Product Training ini, dapatkan dilanjutkan dengan training sbb :  Preventive maintenance D8R  Machine Troubleshooting D8R  Overhauling D8R



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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SEVEN HABITS ( 7 KEBIASAAN BAIK ) 1.



PROAKTIF. Jadilah seseorang yang bersifat Proaktif. Kerjakan sesuatu melalui inisiatif, motivasi yang tinggi, kemauan yang timbul dari diri sendiri. Orang yang reaaktif biasanya baru bertindak setelah ada sesuatu yang menggangu dia, seperti ditanya, disuruh, diminta dan sebagainya.



2.



BEGIN WITH THE END MIND. Mulailah sesuatu pekerjaan dengan tujuan jelas. Jika orang tidak mempunyai target atau tujuan yang jelas maka orang tersebut selamanya akan menemui kegagalan, sebab apa yang ia jalankan atau kerjakan dilakukan tanpa arah ataupun perencanaan yang jelas.



3.



PUT FIRTS THINK FIRTS. Tempatkanlah yang utama dengan tujuan yang jelas. Bila seseorang selalu mengerjakan yang kecil-kecil atau bukan utama, maka ia tidak akan selesai dengan tugasnya.



4.



THINK WIN – WIN. Berpikirlah dan bertindaklah selalu untuk kebaikan maupun keuntungan kedua belah pihak, jangan menjatuhkan orang lain untuk keuntungan diri sendiri.



5.



SEEK TO UNDERSTAND AND TO BE UNDERSTOOD. Belajarlah mengerti apa yang dimaksud atau dipikirkan oleh partner dan barulah mencoba membuat partner mengerti apa yang kita maksud. Kebanyakan orang ingin agar orang lain mengerti apa yang kita inginkan, tapi tidak mau mengerti apa yang orang lain pikirkan.



6.



SYNERGI. Membiasakan diri untuk bekerja sama secara aktif dengan partner agar ada kesimbangan didalamnya. Kemauan dan usaha untu kerjasama ini akan menghasilkan suatu hubungan atau kelompok yang mempunyai Synergi yang tinggi.



7.



SHARPEN THE SAW. Asahlah kebiasaan anda dan teman anda setiap saat agar enam kebiasaan diatas tidak terpolusi oleh kebiasaan lain.



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DAFTAR ISI



KATA PENGANTAR ................................................................................................................... I TRAINING PROFILE ................................................................................................................. II SEVEN HABITS ........................................................................................................................ III DAFTAR ISI .............................................................................................................................IV PENDAHULUAN.......................................................................................................................V BAB I. ENGINE............................................................................................................. 1-1 Spesifikasi Unit .................................................................................................................. 1-1 Intake and Exhaust System ................................................................................................1-4 Fuel System ........................................................................................................................1-9 Cooling System .................................................................................................................1-14 Lubrication System ...........................................................................................................1-19



BAB II. POWER TRAIN ................................................................................................ 2-1 Spesifikasi dan komponen ................................................................................................ 2-1 Torque Divider .................................................................................................................. 2-3 Powershift Transmision .................................................................................................... 2-5 Hidrolik Diagram T/C & Trans ......................................................................................... 2-15 Brake Control Valve ........................................................................................................ 2-23 Final Drive Group ............................................................................................................ 2-25 Diferential Steering ......................................................................................................... 2-31



BAB III. UNDERCARIAGE .............................................................................................. 3-1 Undercariage Komponen .................................................................................................. 3-1



BAB IV. HYDRAULIC IMPLEMENT ................................................................................. 4-1 Implement Diagram & Komponen .................................................................................... 4-1 Pressure and Flow Compensator .................................................................................... 4-10 PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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Dozer Lift Valve ............................................................................................................... 4-21 Quick Drop Valve............................................................................................................. 4-30 Ripper Diverter Valve ...................................................................................................... 4-36



BAB V. ELEKTRIK SYSTEM .....................................................................................................5-1 Strating and Charging Diagram ......................................................................................... 5-1 Electronic Monitoring System .......................................................................................... 5-6 Air Conditioning System ................................................................................................. 5-13 Quick-drop Valve



..................................................................................................... 5-14



BAB VI. LATIHAN SOAL ................................................................................................ 6-1



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Pendahuluan Materi ini akan membahas perubahan desain , lokasi komponen , dan sistem operasi Serial number D8R Seri II (6YZ 1 - UP dan AKA 1 - UP) Track- jenis Tractor. Alat dan sistem kemudi diferensial memiliki pompa terpisah untuk memberikan kinerja yang lebih baik cocok untuk operasi individu dan gabungan. Fitur standar lainnya termasuk : Advanced Modular Cooling System (AMOCS) radiator dengan terpisah Circuit Aftercooler (SCAC), Electronic Brake valve, Electronic Clutch Pressure Control (ECPC) transmisi, kelenjar berulir angkat silinder hidrolik dengan katup cepat -drop yang terletak di bagian atas pelindung radiator, beban sensing, tekanan kompensasi dioperasikan pilot hidrolik , mudah diakses filter oli mesin , dan Caterpillar Monitoring System. D8R juga dapat dilengkapi dengan lampiran opsional seperti sistem mesin pra - pelumasan, sebuah pengisian bahan bakar adaptor bahan bakar cepat , mesin cepat dan power train ganti oli adapter , dan kontrol ganda tilt blade untuk angel dozer. Ganda tilt juga tersedia dengan U dan SU blade. 3406E engine turbocharged dan dilengkapi aftercooler dinilai pada 231 kW (310 hp) pada 2000 rpm dan supply listrik melalui pembagi torsi, transmisi, final drive dan undercarriage.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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1-1



BAB 1 Introduction



STEER SYSTEM COMPARISON D8N One Pump



D8N/D8R Two Pump







Piston-type pump for steering and hydraulics







Piston-type pump for steering only







Steering control valve integrated with implement control valve







Steering controlled by remote pilot valve







Counterbalance valve to prevent overspeeding







Crossover and makeup valves replace counterbalance valve







Steering motor without internal flushing valve







Steering motor with internal flushing valve







Tiller control with separate speed selector and parking brake







Dual twist tiller with integrated speed selector and parking brake



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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HYDRAULIC SYSTEM COMPARISON D8N One Pump



D8N/D8R Two Pump







Piston-type pump for steering and implements







Piston-type pump for implements only







Load sensing, pressure compensated hydraulics with steering priority







Load sensing, pressure compensated hydraulics







Standard Caterpillar cylinders







Threaded gland lift and pin puller cylinders







Individual quick-drop valve for each lift cylinder







Single quick-drop valve similar to the D6R/D7R







Individual ripper function valves







One control valve with pilot operated diverter for all ripper functions



OPTIONAL EQUIPMENT 



Air Conditioning (R-134a)







Fast fill fuel system







Fast oil change system for engine and transmission







Dual tilt cylinders on 8A angle dozer with tilt blade







58 Winch







Engine pre-lubrication system



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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1-3



Sistem pembersih udara pada D8R telah ditingkatkan ukurannya. Sistem saluran udara yang lebih besar membantu meningkatkan keandalan indikator filter udara dan memberikan peningkatan waktu antara perubahan filter udara. Jika D8N perlu dikonversi ke konfigurasi ini, lihat Instruksi Khusus "Mengurangi Pembatasan Saluran Masuk Udara" (Formulir SEHS9883). Komponen saluran masuk dan buang udara adalah: precleaner dan jalur ejector debu, pembersih udara, indikator elemen filter, turbocharger, aftercooler, silinder, katup dan komponen sistem katup, manifold buang, dan muffler.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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Udara masuk yang bersih ditarik melalui dua filter seal radial di rumah air cleaner: Primary filter (tidak diperlihatkan) dan secondary filter (1). Bersihkan filter utama ketika filter element indicator (2) menunjukan pada daerah kuning.bergerak ke zona merah dengan engine running di HIGH IDLE. Setelah primary filter dibersihkan, jika indikator masih bergerak ke zona merah atau warna gas buang bewarna hitam, pasang primary filter element baru dan periksa kembali indikator di HIGH IDLE. Jika indikator masih bergerak ke zona merah, ganti filter sekunder. Kemudian, atur ulang indikator.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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1-5



Udara dari Air cleaner dihisap melalui lubang udara turbocharger melalui putaran kompresor wheel. Udara masuk bertekanan dari sisi kompresor turbocharger dipaksa masuk ke aftercooler (1) melalui pipa saluran masuk udara. Udara melewati core dalam aftercooler, yang menurunkan suhu udara menjadi sekitar 93 ° C (199 ° F).e Engine coolant mengalir melalui core untuk mendinginkan udara yang masuk. Udara dingin mengalir keluar dari aftercooler ke Cylinder head. Keuntungan dari udara dingin adalah efisiensi pembakaran yang lebih besar. Untuk mengukur boost pressure , lepaskan plug dan pasang adaptor, yang kemudian dihubungkan ke pengukur pressure gauge.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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Setelah udara mengalir melalui aftercooler dan menuju cylinder head,Intake valve membuka dan mengarahkan udara ke silinder di mana bahan bakar dicampur di ruang bakar. Ketika exhaust valve terbuka, gas diarahkan ke turbin wheel turbocharger yang menyebabkan kompresor wheel berputar lebih cepat. Setelah melakukan perjalanan melalui turbocharger, gas buang diarahkan melalui mufler (2) dan exhaust pipe, yang terletak di sisi kanan engine (1). Tepat sebelum memasuki exhaust pipe, gas mengalir melewati dust ejector tube (3). Aliran menciptakan sedikit kevakuman pada rumah precleaner melalui dust ejector line (4) untuk menghilangkan debu dan kotoran dari precleaner.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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1-7



Alat bantu ether starting (1) adalah standar pada D8R dan terletak di sisi kiri engine. Grup termasuk katup ether, rakitan klem silinder, tabung pasokan,dan alat penyemprot. Saat menghidupkan mesin di bawah 0 ° C (+ 32 ° F), Mengacu pada Operational dan Maintenance Manual untuk prosedur dan peringatan khusus. Starting aid Solenoid (2) diaktifkan dengan menekan knop alat bantu start (3) setiap dua detik sambil menghidupkan mesin. Setelah mesin menyala, lepaskan sakelar start kunci dan kenop bantu start. Jika



coolant



temperature di atas 37,8 ° C (100 ° F), ether starting tidak dapat diinjeksikan ke rumah saluran udara karena engine coolant temperature switch (4) dimasukkan ke bagian kanan belakang cylinder head. CATATAN: Knop bantuan awal menyuntikkan eter dalam jumlah yang tepat untuk periode dua detik setiap kali kenop ditekan.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



ENGINE



1-8



Skema ini menunjukkan komponen sistem bahan bakar: tangki bahan bakar, shut off valve, drain valve tangki bahan bakar, saluran balik bahan bakar, primary fuel filter, priming pump dan check valve,transfer pump, secondary filter, constan bleed valve, pompa bahan bakar dan gubernur, dan salah satu nozel injeksi bahan bakar. Fuel Transfer pump memindahkan bahan bakar dari tangki ke fuel injection



pump.bypass



valve



pada



fuel



transfer



pump



mempertahankan tekanan pasokan pompa injeksi bahan bakar pada 170 hingga 280 kPa (25 hingga 40 psi).constant bleed valve, terletak di badan fuel pump, mengembalikan sekitar 34 Liter (9 gal.) Per jam bahan bakar dan udara ke tangki. Aliran ini membantu menjaga bahan bakar tetap dingin dan bebas dari udara. Kelompok pompa bahan bakar mengukur bahan bakar dan memuat enam pompa injeksi bahan bakar individual yang meningkatkan tekanan bahan bakar hingga 6.900 kPa (1000 psi). Bahan bakar tekanan tinggi ini mengalir melalui saluran baja ke direct injection fuel nozzle , yang menyemprotkan pola pengabutan bahan bakar yang halus ke ruang bakar. PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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Tangki bahan bakar D8R (1) terletak di bagian belakang alat berat di belakang cabin operator. Saringan (tidak diperlihatkan) dalam tabung pengisian bahan bakar menjaga kotoran keluar dari tangki bahan bakar selama pengisian bahan bakar. Tutup berventilasi (2) mencegah penumpukan tekanan di tangki bahan bakar dan juga mencegah bahan bakar pendingin dari menciptakan ruang hampa udara. Tangki bahan bakar telah dirancang dengan lekukan (5) di tengah atas untuk meningkatkan pandangan operator untuk operasi pemasangan belakang. Kapasitas tangki adalah sekitar 625 Liter (165 gal.). Fuel level sender terletak pada bagian atas tanki (3). Uel level sender memberikan sinyal ke fuel level gauge di monitor panel. Jika pengukur dasbor tidak berfungsi, operator dapat melihat bagian atas sender untuk menentukan tingkat bahan bakar tangki. Adaptor fast fill 2G-9000 opsional (4) terletak di kiri bawah tangki yang memungkinkan bahan bakar dipompa ke dalam tangki dengan lebih cepat untuk pengisian bahan bakar yang lebih cepat dan waktu henti yang lebih singkat saat pengisian bahan bakar. Untuk menghubungkan ke adaptor, gunakan Nozzle 4C6717 yang tersedia di sistem suku cadang Caterpillar.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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1-10



Aliran bahan bakar dari tangki ke sistem bahan bakar engine dapat dimatikan dengan menggerakkan gagang shutoff valve (1) ke bawah. Return hose bahan bakar dari sistem memasuki bagian bawah tangki melalui selang tengah (2). Untuk mengalirkan sedimen dan akumulasi kelembaban dari dasar tangki ke wadah yang sesuai, buka drain valve(3) sampai bersih, bahan bakar diesel mulai mengalir.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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ENGINE



1-11



Seperti yang dinyatakan sebelumnya, tangki bahan bakar (1) dilengkapi dengan fuel level sender (2) yang terletak tepat di belakang operator di bagian atas tangki bahan bakar. Fuel sender menggunakan plastic float (3) yang meluncur ke atas dan ke bawah dan memutar Rod (4) saat level bahan bakar berubah. Rotasi rod mengirimkan sinyal listrik ke dash gauge (5) dan, pada saat yang sama, indikator mekanis di bagian atas pengirim menunjukkan perkiraan level fuel di tangki.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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1-12



Fuel pump dan governor terletak di sisi kiri engine (1). Primary fuel filter dan priming pump (2) dan secondary fuel filter (4) terletak di sisi kiri engine di belakang pintu akses. Fuel heater (3) bersifat opsional dan menggunakan cairan pendingin engine untuk memanaskan bahan bakar diesel. Fuel transfer pump (5 dan 7) mentransfer bahan bakar dari tangki, melalui primary fuel filter ke secondary fuel filter. Setelah bahan bakar disaring, bahan bakar diarahkan ke rumah bahan bakar. Fuel transfer pump terletak di bagian depan depan rumah bahan bakar dan digerakkan oleh camshaft fuel injection pump . fuel ratio control (6) membatasi jumlah bahan bakar ke silinder selama peningkatan kecepatan engine (akselerasi) untuk mengurangi asap knalpot. Disesuaikan dengan benar, juga meminimalkan jumlah jelaga di engine. Kontrol rasio bahan bakar memiliki baut tahan tamper yang putus saat dilepas. Penyesuaian dan perbaikan harus dilakukan oleh personel yang berwenang.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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Advanced Modular Cooling System (AMOCS) pada D8R menggunakan modul radiator dua-lintasan untuk meningkatkan efisiensi radiator. Selama operasi normal, water pump mengarahkan engine coolant melalui oil cooler engine dan kemudian ke blok silinder. Saat cairan pendingin mengalir melalui blok kemudian cylinder head, semua coolant dikumpulkan di thermostat regulator housing. Ketika coolant temperatur melebihi 90°C (195°F), regulator membuka dan mengarahkan engine coolant ke bagian depan tangki bawah radiator .coolant panas melakukan perjalanan sembilan modul inti individu dan turun ke bagian belakang radiator ke bagian belakang tangki bawah dan kemudian kembali ke pompa air. Shunt line memberikan tekanan positif pada saluran masuk pompa air untuk mengurangi kavitasi pompa air. Saluran ventilasi udara menghilangkan udara dari sistem pendingin saat sistem sedang diisi dan selama operasi. Tangki ekspansi adalah reservoir dan mempertahankan volume ekspansi pendingin saat suhu meningkat.



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Tampilan penampang ini menunjukkan jalur aliran coolant melalui radiator AMOCS. Bagian atas setiap modul inti umumnya terhubung ke tangki ekspansi (tidak diperlihatkan) yang terletak tepat di atas inti. Setiap inti memiliki sembilan sirip baja per 25 mm (1,0 inci) dan menggunakan konstruksi tabung kuningan di dalam inti. Inti enam sirip baja per 25 mm (1,0 inci)



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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Slide ini menunjukkan komponen radiator. Setiap inti (1) memiliki dua lubang (2), satu untuk pendingin masuk dan satu untuk pendingin keluar. Core diatur ke tangki bawah (3) ke dalam lubang (4) menggunakan segel (5) untuk menutup koneksi. Di tangki bawah, lubang saluran masuk pendingin (6) dan lubang keluar (7) menghubungkan inti ke mesin. Minyak mineral akan merusak segel (5). Jika ada oli ditemukan dalam sistem pendingin, periksa semua segel.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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Fill tube dan radiator cap (1) terletak di bagian atas expansion tank untuk sistem pendingin. Expansion tank terletak tepat di atas radiator di kompartemen engine . Akses ke fill tube disediakan dengan mengangkat pintu berengsel di atas kompartemen engine. Level cairan pendingin yang benar dapat diperiksa dengan dua cara. Sight glass (2) di expansion tank terlihat di sisi kiri kompartemen engine. Sight glass harus selalu diisi dengan cairan pendingin. Jika ada udara yang terlihat di sight glass,cairan pendingin perlu ditambahkan ke expansion tank. Saat menambahkan pendingin ke sistem, pertahankan level antara ujung atas dan bawah dari bagian fill tube. CATATAN: Kapasitas isi ulang cooling sistem sekitar 92 Liter (24 gal).



PERHATIAN….! Tambahkan pendingin hanya setelah mesin berhenti dan tutup radiator cukup dingin untuk menyentuh dengan dasar tangan Anda. Buka tutup radiator secara perlahan untuk mengurangi tekanan sistem. Uap bisa menyebabkan cedera



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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Electronic Monitoring System temperatur switch (EMS) (1) terletak di bagian kiri belakang cilynder head. Coolant flow switch (2) terletak di saluran masuk ke pompa air. Coolant temperature gauge sender (3) terletak thermostah regulator housing di kanan depan mesin.



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Sistem pelumasan terdiri dari komponen-komponen berikut: Oil pan, Oil pump dan relief valve, Oil cooler dan bypass valve, Oil filter dan bypass valve, saluran ke dan dari turbocharger, dan suction bell (Strainer). Selama operasi normal, Oil pump mengarahkan oli dari oil pan ke oil cooler, Oil filter, dan kemudian ke turbocharger dan cilynder oil manifold. Ketika engine dingin, baik oil cooler dan bypass valve filter akan terbuka, memungkinkan oli untuk melewati oil filter sebelum oli ke turbocharger dan blok. Saat oli menghangat, perbedaan tekanan di bypass valve berkurang, dan valve menutup untuk memungkinkan aliran oli normal melalui oil cooler dan oil filter. Jika perbedaan tekanan dari kedua bypass valve terlampaui karena tersumbat, oli akan selalu mengalir melalui sistem untuk melumasi engine. Relief valve dipasang di oil pump. Relief valve mengontrol tekanan oli yang dikirim oleh pompa ke sistem. Oil pump mampu menghasilkan lebih banyak oli daripada yang dibutuhkan, dan kelebihannya diarahkan kembali ke saluran masuk pompa.



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Di sisi oil pan (1) adalah drain valve (2). Akses disediakan melalui



pelindung



engine



yang



lebih



rendah.



Untuk



mengalirkan oli mesin, pasang pipa 25 mm (1 in.) Dengan 1 11 NPTF dan selang fleksibel yang terhubung, kemudian buka drain valve (2) untuk mengarahkan oli bekas ke dalam wadah yang sesuai. Dipstick engine (3), fill tube (4), dan fast oil change fitting (5) terletak di dalam pintu akses ruang engine kiri. Untuk menggunakan fast oil change fitting (5), dengan menggunakan Nozel 126-7539. Di sisi kanan engine terdapat komponen berikut: oil cooler (6), oil filter (7), Schedule Oil Sampling tap (S • O • S) (8), Pressure tap (9), jalur suplai oli ke turbocharger (10), oil return dari turbocharger (11), dan engine oil pressure switch (12) untuk EMS.



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D8R juga dapat dilengkapi dengan sistem start pra-pelumasan engine (opsional). Sistem start pra-pelumasan akan membuat engine tersupply oli sebelum starter mulai menghidupkan mesin. Sistem ini mengurangi keausan komponen engine yang biasanya terjadi selama start-up. Untuk menghidupkan mesin, putar sakelar mulai kunci (panah) ke MULAI dan tahan tombol di posisi ini untuk mengaktifkan sistem pra-pelumasan mesin dan start engine. Ketika tekanan oli yang memadai tersedia, sistem pra-pelumasan akan terlepas dan berhenti selama tiga detik. Starter kemudian akan menghidupkan dan menghidupkan mesin secara otomatis. Lepaskan kunci setelah mesin dinyalakan.



NOTE: Sistem pra-pelumasan engine dirancang agar tidak dapat beroperasi jika engine dihidupkan ulang dalam waktu dua menit setelah dihentikan.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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1-21



Pra-pelumasan mesin dilakukan dengan



menggunakan



starter



mesin yang dimodifikasi yang dilengkapi dengan pompa tipe roda gigi. Ketika starter berputar, pompa roda gigi menghisap oli dari oil pan dan mengarahkan aliran melalui one way check valve ke dalam sistem pelumasan engine. Timer / solenoida mengendalikan sistem dan terletak di atas bagian belakang mesin. Fast oil change fitting terhubung ke tee di saluran hisap ke pompa roda gigi pra-pelumasan. Engine oil pressure switch (panah) terletak di sisi kanan engine tepat di belakang power train oil cooler .engine oil pressure witch ini digunakan untuk mengirim sinyal ke



timer / solenoida pra-pelumasan ketika tekanan oli dalam sistem mencapai 28 kPa (4 psi). Oli dari pompa roda gigi diarahkan ke filter oli engine. Check valve digunakan untuk membatasi oli agar tidak mengalir ke pompa roda gigi setelah mesin dihidupkan.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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1-22



Untuk menghidupkan mesin menggunakan sistem pra-pelumasan, operator harus memutar sakelar mulai kunci ke posisi START. Sakelar start kunci memberi energi pada main relay dan mengirimkan arus ke timer / solenoida pra-pelumasan melalui kabel 307-OR. Karena operator memegang sakelar start kunci pada posisi awal, timer / solenoida pra-pelumasan mengarahkan arus melalui kabel 301 BU ke ujung berlawanan dari kumparan motor starter. Arus ini menutup relai starter dan menghubungkan jalur untuk arus baterai untuk memutar motor starter. Namun, arus tidak memberi energi pada solenoid yang menghubungkan pinion dengan flywheel engine. Motor starter berputar menggerakkan pompa roda gigi di ujung motor. Pompa roda gigi menghisap oli dari oil pan engine dan mengarahkan oli ke dalam sistem pelumasan mesin untuk melumasi mesin. Check valve terletak di jalur tekanan untuk mencegah aliran balik oli dari mesin setelah dimulai, dan pompa oli mesin mulai menghasilkan aliran. Ketika tekanan di oil galery meningkat menjadi 28 kPa (4 psi), engine oil pressure cut off akan terbuka. Kondisi ini PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



ENGINE



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menyebabkan arus ke motor starter berhenti dan timer / solenoida pra-pelumasan berhenti selama tiga detik. Jeda ini memungkinkan motor starter melambat sebelum pinion drive menggunakan roda gila engine. Setelah waktu jeda, pengatur waktu pra-pelumasan / solenoida mengirimkan arus melalui kawat 337 WH, yang memberi energi pada relai starter dan siklus normal untuk engine start-up. Pinion motor starter kemudian menggerakkan roda gila dan starter menghidupkan mesin. Ketika mesin hidup, operator melepaskan sakelar start kunci.



NOTE: Sistem pra-pelumasan tidak dapat beroperasi jika mesin dihidupkan ulang dalam waktu dua menit setelah dimatikan. Dalam dua menit ini, mesin akan langsung berputar ketika sakelar start kunci diaktifkan.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



POWER TRAIN



2-1



BAB 2 POWER TRAIN



Slide ini menunjukkan perbandingan sistem satu pompa D8N dengan sistem dua pompa D8N dan D8R. Tata letak komponen antara mesin sangat mirip kecuali untuk yang berikut: 



Pompa implement dan kemudi terpisah.







Katup pilot yang terhubung ke bagian bawah tuas pengganti menggantikan grup katup kemudi.







Pompa transmisi memiliki bagian tambahan dan dipasang di ujung pompa implement







Katup kontrol implement yang direlokasi.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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2-2



Skema ini menunjukkan komponen dan aliran oli di sistem hidrolik power train. Bagian tiga dari tiga bagian pompa power train menghilangkan oli dari kedua case transmisi dan torque converter dan mengarahkan oli ke case bevel gear. Bagian dua mengambil oli dari bevel gear case dan mengarahkan oli ke valve relief yang mengatur, kemudian ke torque converter sebagai oli pengisian dan ke rumah roda gila untuk pelumasan. Bagian satu menarik oli dari bevel gear case dan mengarahkan oli melalui filter oli power train, ke katup prioritas, lalu ke katup rem parkir dan servis serta katup kontrol transmisi sebagai oli pasokan untuk kopling. Katup rasio mengarahkan oli dari katup kontrol transmisi ke konverter torsi sebagai oli pengisian tambahan. Semua oli outlet konverter diarahkan melalui oli pendingin yang dipasang engine ke rem, transmisi, dan roda gigi bevel sebagai oli pendingin dan pelumasan.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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2-3



Torque Divider Traktor tipe Track D8R menggunakan pembagi torsi (panah) untuk mentransfer daya engine ke transmisi. Pembagi torsi serupa dengan yang digunakan pada traktor tipe track Caterpillar lainnya. Pembagi torsi menyediakan koneksi hidrolik dan mekanis dari engine ke transmisi. Konverter torsi menyediakan koneksi hidraulik, sedangkan set roda gigi planetary menyediakan koneksi mekanis. Selama operasi, set roda gigi planet dan konverter torsi bekerja bersama untuk memberikan peningkatan torsi saat beban pada mesin meningkat.



Ilustrasi ini menunjukkan pembagi torsi khas seperti yang digunakan dalam D8R. Baling-baling, rumah yang berputar, dan roda gigi matahari ditunjukkan dengan warna merah. Komponen-komponen ini berada pada koneksi mekanis langsung ke roda gila mesin. Turbin dan gear ring, ditunjukkan



dengan



warna



biru,



terhubung. Pembawa planet dan poros keluaran, ditunjukkan dengan warna kuning, juga terhubung. Stator ditampilkan dalam warna coklat. Roda gigi dan poros planet berwarna hijau. Bantalan ditunjukkan dengan warna kuning.



Karena gigi matahari dan impeler terhubung ke roda gila, mereka akan selalu berputar dengan kecepatan engine. Saat impeller berputar, ia mengarahkan oli ke bilah turbin, menyebabkan turbin berputar. Rotasi turbin menyebabkan ring gear berputar. Selama kondisi NO LOAD, komponen-komponen roda gigi planet berputar sebagai satu unit pada putaran yang sama dan roda gigi planet tidak berputar pada porosnya.. PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



POWER TRAIN



2-4



Saat operator memuat alat berat, poros output melambat. Penurunan kecepatan poros output menyebabkan rpm pembawa planet berkurang. Berkurangnya rotasi pembawa planet menyebabkan gerakan relatif antara gigi matahari dan pembawa planet menyebabkan roda gigi planet berputar. Memutar roda gigi planet mengurangi rpm gear ring dan turbin. Pada titik ini, torsi terbagi dengan torque converter yang mengalikan torsi secara hidrolik, dan set roda gigi planet mengalikan torsi secara mekanis.



Beban yang sangat berat dapat menghentikan mesin. Jika mesin berhenti, poros keluaran dan pembawa planet tidak akan berputar.



Kondisi ini menyebabkan ring gear dan turbin berputar perlahan ke arah berlawanan putaran mesin. Multiplikasi torsi maksimum dicapai hanya saat ring gear dan turbin mulai berputar ke arah yang berlawanan.



Selama semua kondisi beban, konverter torsi menyediakan 70% dari output, dan set roda gigi planetary menyediakan 30% sisanya dari output.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



POWER TRAIN



2-5



Power Shift Transmission



Transmisi D8R terletak di bagian belakang alat berat untuk memudahkan pelepasan dan pemasangan. Transmisi power shift (panah) planetary tiga kecepatan maju, tiga kecepatan mundur mentransfer daya dari engine ke drive final. Transmisi berisi tiga kopling kecepatan yang dikendalikan secara hidrolik dan dua kopling arah yang dikendalikan secara hidrolik. Operator secara manual memilih arah dan kisaran kecepatan. Dengan kecepatan transmisi dan kopling directional ENGAGE, transmisi mengirimkan daya ke bevel gear dan pinion, planetary drive, planetary steer sisi kiri, sisi kanan planetary equalizer, dan kemudian ke final drive.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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POWER TRAIN



2-6



Port tes tekanan kopling cepat (P1) (1) dan port uji tekanan kopling terarah (P2) (2) terletak di bagian belakang rumah transmisi. Colokan dilepas dan diganti dengan alat uji untuk mengukur tekanan P1 dan P2. Tap tekanan masuk konverter torsi P3 (3) dan tap tekanan pelumas transmisi (4) juga terletak di bagian belakang rumah transmisi.



Untuk mengukur tekanan pembukaan katup prioritas, tukar sumbat tekanan katup prioritas (5) dengan keran tekanan masuk konverter torque (3).



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



POWER TRAIN



2-7



Slide ini menunjukkan tampilan bagian dari grup transmisi tipikal. Kelompok planet ini memiliki dua kopling terarah dan tiga percepatan yang diberi nomor secara berurutan (1 hingga 5) dari belakang transmisi ke depan. Kopling No. 1 dan 2 adalah kopling directional terbalik dan maju. Kopling No. 3, 4, dan 5 adalah kopling kecepatan ketiga, kedua, dan pertama. Kopling No. 5 adalah kopling yang berputar. Dalam tampilan penampang transmisi ini, poros input dan roda gigi input ditampilkan dalam warna merah. Poros keluaran dan gir keluaran matahari berwarna biru. Roda gigi cincin ditampilkan dalam warna hijau. Pembawa planet berwarna coklat. Roda gigi dan poros planet ditampilkan dalam warna oranye. Cakram kopling, pelat kopling, piston, pegas, dan bantalan ditunjukkan dengan warna kuning. Rumah kopling stasioner ditampilkan dalam warna abu-abu.Roda gigi input matahari condong ke poros input dan menggerakkan kereta gigi directional. Poros keluaran digerakkan oleh roda gigi matahari No. 3 dan 4 dan kopling berputar No. Pembawa planet No.1 dipegang saat kopling No. 1 diaktifkan. Saat diaktifkan, kopling putar No. 5 mengunci komponen output (untuk gigi FIRST) ke poros output



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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POWER TRAIN



2-8



.



Tabung pengisian oli power train (1) dan dipstick (2) terletak di bawah penutup berengsel di sisi kanan mesin tepat di depan tangki oli hidrolik.



CATATAN: Kapasitas isi ulang sistem power train adalah sekitar 144 Liter (38 gal.).



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



POWER TRAIN



2-9



Pompa oli power train terdiri dari bagian pengisian katup kontrol transmisi (1), bagian pengisian torque converter (2), dan torque converter dan bagian scavenge transmisi (3).



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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POWER TRAIN



2-10



The filter transmisi (1) terletak di depan tangki hidraulik di sisi kanan mesin. Rumah filter saringan berisi keran tekanan pompa transmisi (2), keran S • O • S (3), sakelar tekanan pintas filter (4), dan sakelar penimpaan suhu (5) yang ada di bagian belakang saringan perumahan. Katup bypass filter transmisi akan terbuka ketika filter menjadi terbatas atau ketika oli dingin dan tebal. Filter bypass terjadi pada sekitar 175 kPa (25 psi). Saat oli dingin saat start-up, ia akan melewati filter; namun, saklar pengalih suhu (5) akan mencegah sinyal memperingatkan operator ketika suhu oli di bawah 52 ° C (125 ° F). Jika filter dibatasi setelah oli menghangat, sakelar tekanan katup bypass (4) terbuka dan mengirimkan sinyal ke EMS untuk memperingatkan operator bahwa filter oli power train perlu diservis.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



POWER TRAIN



2-11



D8R menggunakan katup drain "tipe ekologi" untuk membantu mencegah tumpahan atau kehilangan oli ketika sistem transmisi dikeringkan. Untuk mengalirkan oli, lepaskan sumbat (1), pasang pipa 12,7 mm (0,5 in.) Dengan 1/2 - 14 ulir NPTF, dan hubungkan selang fleksibel ke pipa. Kemudian, putar katup pembuangan (2) dengan kunci pas allen. Katup dapat digunakan untuk mengontrol laju di mana minyak dikeringkan ke wadah yang sesuai dengan membukanya sebagian atau seluruhnya. Layar scavenge transmisi terletak di belakang rumah katup pembuangan.



Sistem Penggantian Oli 108-4313 tersedia untuk D8R. Grup ini mencakup mesin pengisian cepat dan fitting pengisian oli power train dan grup selang. Fitting pengisian oli power train cepat (panah) untuk case gear bevel terletak di sisi kiri engine di sebelah dipstick oli engine. Untuk menggunakan fitting pengisian cepat, 126-7538 Nozzle Assembly harus dibeli.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



POWER TRAIN



2-12



Colokan pembuangan untuk bak oli power train utama terletak di bagian bawah kasing utama dan rangka rangka di bawah traktor. Untuk mengalirkan oli, lepaskan sumbat (panah) yang menutupi katup pembuangan. Pasang Selang Putar 4C8563 atau pipa 25 mm (1 in.) Dengan 1 - 11 1/2 NPTF utas untuk melepas katup pembuangan (tidak diperlihatkan) dan memulai aliran minyak. Untuk menghentikan aliran minyak, lepaskan selang putar atau pipa dan pegas akan menutup katup.



D8R menggunakan katup drain "tipe-ekologi" untuk membantu mencegah tumpahan atau kehilangan oli ketika rumah konverter torsi dikuras. Untuk mengalirkan oli, lepaskan sumbat (1), pasang pipa 12,7 mm (0,5 in.) Dengan 1/2 - 14 ulir NPTF dan hubungkan selang fleksibel ke pipa. Kemudian, putar katup pembuangan (2) dengan kunci inggris. Katup dapat digunakan untuk mengontrol laju di mana minyak dikeringkan ke wadah yang sesuai dengan membukanya sebagian atau seluruhnya. Layar scavenge konverter torsi (tidak terlihat) terletak tepat di dalam flensa selang scavenge (3).



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



POWER TRAIN



2-13



Katup pelepas outlet torque converter (1) dipasang pada case torque converter. Tekanan outlet torque converter dapat diperiksa pada keran tekanan (2). Pengirim pengukur suhu oli power train (3) terletak di sebelah kiri keran tekanan. Sakelar suhu oli power train EMS (4) terletak di sebelah keran tekanan.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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POWER TRAIN



2-14



Pendingin oli power train (panah) terletak di sisi kanan ruang engine. Pendingin adalah desain oli ke air. Oli dari torque converter mengalir melalui katup pelepas outlet torque converter dan dikirim ke oil cooler. Setelah oli mengalir melalui pendingin, oli dikirim ke sirkuit pelumasan untuk rem dan transmisi.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



POWER TRAIN



2-15



Power Train Hydraulic System Skema ini menunjukkan komponen dan aliran oli di sistem hidrolik power train. Warna yang digunakan untuk mengidentifikasi berbagai tekanan dalam sistem adalah: 1. 2. 3. 4. 5.



Red - Pump and P1 pressure. Red and White Stripes - P2 pressure and brake release pressure. Orange - Torque converter pressure. Brown - Lubrication (lube) pressure. Green - Drain or reservoir oil. Sistem ini dilengkapi dengan pompa tipe gigi tiga bagian. Dalam pandangan ini, bagian pemulung berada di sebelah kiri, bagian pengisian torque converter "fase split" ada di tengah dan bagian pengisian katup kontrol transmisi berada di sebelah kanan. Istilah "fase split" mengacu pada penyelarasan dua pasang roda gigi pada



poros yang tidak disinkronkan dan akan memasok aliran dalam pulsa alternatif. Desain ini menghasilkan aliran yang dibasahi (lebih halus) ke torque converter.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



POWER TRAIN



2-16



Filter transmisi menggunakan tabung ulir yang menggunakan pegas untuk menempatkan filter di pangkalan. Filter memiliki port pengambilan sampel oli, keran tekanan oli, katup bypass filter yang disetel sekitar 175 kPa (25 psi), sakelar bypass, dan sakelar suhu oli power train. Setelah oli disaring, aliran dikirim ke grup kontrol rem, makeup dan katup prioritas yang mengarahkan aliran ke katup kontrol transmisi dan sistem rem. Posisi NETRAL berada pada spul directional dari katup kontrol transmisi. Sumber oli untuk pelumasan penggerak pompa telah diubah dari sisi outlet pendingin ke sisi inlet konverter torsi. Sebuah lubang dipasang di garis untuk membatasi aliran. Tidak ada perubahan yang dilakukan pada pengoperasian katup kontrol transmisi, konverter torsi, katup pelepas outlet konverter torsi, dan pendingin.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



POWER TRAIN



2-17



Katup kontrol transmisi untuk D8R dengan kemudi diferensial sangat mirip dengan katup kontrol transmisi di banyak mesin lain. Perbedaan utama adalah mesin pengarah diferensial memiliki penahan NETRAL pada spul directional. Kontrol tiller putaran ganda menggunakan NEUTRAL dengan operasi FORWARD dan REVERSE. Operator memilih arah dengan memutar tuas anakan maju ke detent untuk FORWARD atau ke belakang ke detent untuk REVERSE. Anakan ditahan untuk menahan arah yang dipilih sampai operator secara manual melepaskannya. Posisi NETRAL dipilih oleh penahanan antara FORWARD dan REVERSE.



The components of the transmission control valve are: Spool pemilih kecepatan: mengarahkan oli (P1) ke kopling kecepatan yang sesuai. Directional selector spool: mengarahkan oli (P2) ke directional clutch yang sesuai. Lubang disaring: memberikan penurunan tekanan dan waktu tunda dalam aliran oli ke piston beban untuk mengontrol keterlibatan kopling. Katup kontrol transmisi untuk D8R dengan kemudi diferensial sangat mirip dengan katup kontrol transmisi di banyak mesin lain. Perbedaan utama adalah mesin pengarah diferensial memiliki penahan NETRAL pada spul directional. Kontrol tiller putaran ganda menggunakan NEUTRAL dengan operasi FORWARD dan REVERSE. Operator PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



POWER TRAIN



2-18



memilih arah dengan memutar tuas anakan maju ke detent untuk FORWARD atau ke belakang ke detent untuk REVERSE. Anakan ditahan untuk menahan arah yang dipilih sampai operator secara manual melepaskannya. Posisi NETRAL dipilih oleh penahanan antara FORWARD dan REVERSE. Komponen katup kontrol transmisi adalah: Spool pemilih kecepatan: mengarahkan oli (P1) ke kopling kecepatan yang sesuai. Directional selector spool: mengarahkan oli (P2) ke directional clutch yang sesuai. Lubang disaring: memberikan penurunan tekanan dan waktu tunda dalam aliran oli ke piston beban untuk mengontrol keterlibatan kopling. Memodulasi katup pelepas dan memuat piston: mengontrol laju peningkatan tekanan pada kopling dan membatasi tekanan kopling kecepatan maksimum (P1). Katup rasio: melindungi torque converter saat dingin dimulai dengan membatasi tekanan oli (P3) yang mengalir ke torque converter. Katup rasio konverter juga memastikan modulasi kopling dimulai pada tekanan "awal" dengan mengurangi tekanan P3 selama setiap shift. Oli P1 bekerja pada salah satu ujung katup rasio dan minyak P3 bekerja pada ujung katup yang berlawanan. Rasio antara luas permukaan P1 dengan luas permukaan P3 adalah sekitar 4: 1. Katup diferensial tekanan: mengontrol urutan kopling dengan mempertahankan perbedaan tertentu antara kopling kecepatan dan tekanan kopling terarah. Katup diferensial memastikan kopling kecepatan terisi sebelum kopling terarah. Sebagian besar energi dan beban kejut dari sebuah shift kemudian dibawa oleh directional clutch. Katup diferensial juga secara hidrolik mencegah pengait kopling ketika operator menghidupkan mesin dengan tuas pemilih transmisi pada posisi roda gigi dan sakelar start netral tidak beroperasi. Selama shift, ujung kanan katup diferensial berfungsi sebagai katup periksa dan mengarahkan oli dari ruang piston beban untuk mengalir. Lubang A: mengontrol laju pengisian kopling kecepatan untuk memastikan bahwa semua fungsi kontrol diurutkan dengan benar. Lubang A kadang-kadang disebut "lubang kontrol aliran." Orifice B: menyediakan pemompaan cepat pompa dengan memungkinkan jalur tekanan rendah untuk membersihkan udara dari saluran selama start dingin dan juga menyediakan jalur untuk oli tekanan P1 untuk mengalir ketika mesin dihentikan. Jika operator mematikan mesin di gigi maka segera restart mesin, mesin bisa bergerak jika oli tekanan P1 tidak mengalir. Lubang C: membatasi perjalanan beban piston. Lubang itu sebenarnya adalah tiga lubang terpisah. Tergantung pada aplikasinya, satu atau dua lubang ini dicolokkan dengan sekrup yang disetel. Setidaknya satu dari tiga lubang harus selalu tetap terbuka. Lubang-lubang ini berada di badan katup di atas ruang piston beban ketika badan katup kontrol transmisi dibongkar. PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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POWER TRAIN



2-19



Tekanan awal diciptakan oleh pegas ketegangan sebelum piston beban mulai bergerak ke kiri untuk mengompresi pegas piston beban. Tekanan awal terjadi tepat sebelum dimulainya modulasi. Pengaturan tekanan awal sangat penting untuk katup kontrol transmisi ini. Jika tekanan awal terlalu rendah, pergeseran keraguraguan dapat terjadi. Pengaturan tekanan awal yang tinggi akan menyebabkan pergeseran yang keras dan akan mengurangi umur komponen transmisi. Saat memeriksa tekanan awal, lepaskan steker di katup kontrol transmisi berlabel "LP." Melepas sumbat ini mengalirkan oli ke ruang piston muatan. Katup pelepas dan piston beban dapat disesuaikan dengan shim. Jika tekanan kopling P1 tidak dalam spesifikasi, lihat manual servis untuk prosedur yang benar. Selalu sesuaikan katup kontrol transmisi untuk tekanan awal dan bukan tekanan P1 pada keterlibatan penuh kopling.



Katup diferensial tidak disesuaikan shim. Jika tekanan diferensial tidak sesuai spesifikasi, ganti pegas atau ganti katup. Karena katup rasio membatasi tekanan P3 maksimum daripada minimum, tekanan P3 tidak boleh disesuaikan. Peningkatan tekanan P3 dapat menyebabkan kegagalan konverter torsi.



INSTRUCTOR NOTE: For more information about the transmission control valve operation, refer to the Technical Instruction Module "Manually Controlled Power Shift Transmission Control Valve" (Form SEGV2576).



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



POWER TRAIN



2-20



Ketika perpindahan dibuat dari NETRAL ke First Speed FORWARD, kopling No. 3 dibuka untuk dikeringkan. Tekanan dalam sistem berkurang, dan kopling No. 5 dan 2 dimodulasi hingga mencapai tekanan yang sesuai.



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D8R



POWER TRAIN



2-21



Grup kontrol anakan D8R menggabungkan sakelar start netral pada tuas anakan. Jika operator mencoba menghidupkan mesin dengan tuas tiller di FORWARD atau REVERSE, sakelar start netral menonaktifkan sirkuit start engine. Operator harus memindahkan tuas kemudi ke NETRAL sebelum mesin akan hidup. Jika sakelar start netral tidak berfungsi dengan benar dan mesin dihidupkan, katup kontrol transmisi akan mencegah mesin dari bergerak karena katup diferensial tidak akan bergerak ke kanan ke posisi "set". Dengan tidak bergerak ke posisi "set", oli yang memasuki ruang katup diferensial terbuka untuk mengalir melalui lorong di sekitar katup, yang menjaga oli tidak diarahkan ke kopling arah..



NOTE: Posisi "set" adalah posisi katup diferensial ketika jalur di sekitar spul diferensial diblokir oleh spul pemilih arah. Dalam posisi "set", lubang di spool katup diferensial telah bergerak melewati bagian ini dan diblokir oleh badan katup.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



POWER TRAIN



2-22



Grup katup kontrol rem berisi katup rem parkir (1) dan katup rem servis (2) di bagian atas dan katup pelepas pengatur dan katup prioritas di bagian bawah. Tap tekanan (3) di bagian atas badan katup untuk menguji tekanan rem, dan keran (4) di sisi badan katup adalah untuk menguji tekanan pengisian konverter torsi. Di sisi kiri badan katup terdapat steker (5) yang dapat dilepas dan keran tekanan dipasang untuk memeriksa tekanan prioritas sebelum masuk ke katup rem parkir.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



POWER TRAIN



2-23



Grup katup kontrol rem menggabungkan katup rem parkir dan servis serta katup prioritas transmisi menjadi satu kelompok. Fungsi katup rem parkir dan servis tetap sama dengan katup terpisah dalam sistem pompa tunggal. Katup rem parkir adalah katup ON / OFF, dan katup rem servis adalah katup penurun tekanan. Fungsi katup prioritas tetap sama, tetapi katup bantuan pengatur telah ditambahkan. Katup pelepas pengatur mempertahankan tekanan pompa torque converter sehingga oli inlet torque converter dapat membantu mengisi cengkeraman transmisi ketika dilakukan pergantian.



Oli dari bagian pengisian transmisi pompa mengalir ke ujung bawah badan katup dan pertama kali dikirim melalui saluran internal ke spool rem parkir. Ketika tuas rem parkir berada di posisi TERLIBAT, aliran ke kumparan rem layanan diblokir. Ketika tuas rem parkir dinaikkan ke posisi RELEASED, oli dikirim melalui jalur pasokan rem ke spool rem servis. Jika rem servis dilepaskan, plunger rem servis menahan spul rem terbuka. Minyak mengalir melalui lintasan di badan katup dan melalui lintasan dan tabung di case utama traktor ke piston rem di mana rem ditahan di posisi RELEASED. Tekanan pelepas rem kira-kira 2950 kPa (425 psi).



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



POWER TRAIN



2-24



Ketika pedal rem servis ditekan sebagian, spul rem servis memiliki gaya yang lebih kecil pada pegas dan tekanan oli di piston rem berkurang. Tindakan pengurangan tekanan ini memungkinkan pegas rem untuk ENGAGE sebagian menginjak rem dan mengurangi kecepatan alat berat. Ketika pedal rem servis penuh, kurang dari 70 kPa (10 psi) tersedia. Jika mesin dalam kecepatan dan arah, konverter torsi dalam kondisi stall. Ingat, mesin dapat berkendara melalui GIGI PERTAMA dengan rem yang ENGAGE. Setelah oli dari pompa pengisian transmisi mengisi sistem rem dan tekanan meningkat menjadi 2900 kPa (420 psi), katup prioritas terbuka dan oli mengalir langsung ke katup kontrol transmisi. Konverter torsi pengisian oli mengalir ke grup katup dan menuju ke katup relief pengatur. Katup ini disetel untuk dibuka pada 880 kPa (130 psi) dan ketika tekanan melebihi nilai ini, katup bergerak ke bawah dan oli mengalir ke konverter torsi. Selama shift, tekanan pasokan transmisi berkurang, katup periksa terbuka dan oli konverter torsi mengalir ke katup kontrol transmisi untuk membantu mengisi kopling. Setelah kopling transmisi diisi dan tekanan pasokan transmisi meningkat di atas 880 kPa (130 psi), katup periksa menutup dan mengarahkan aliran oli dari bagian pengisian konverter torsi pompa ke konverter torsi. Dengan meningkatnya tekanan pasokan transmisi, oli terus mengalir melalui katup prioritas ke katup kontrol transmisi dan terjadi modulasi kopling. Manfaat lain dari sistem tiga pompa adalah aliran minyak pelumas rem sedikit meningkat.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



POWER TRAIN



2-25



Tampilan sectional sisi kiri ini menunjukkan final drive, grup rem, dan diferensial kemudi dan planetary. Tenaga dari transmisi ditransmisikan dari diferensial kemudi (ungu) dan poros gandar tengah (kuning) ke rem (kuning gelap) dan final drive melalui poros gandar luar (kuning). The final drive components consist of the following: - Outer planetary gears (green) - Outer sun gear (green) - Outer carrier (green) - Ring gear (gray) - Inner planetary gears (blue) - Inner sun gear (blue) splined to the outer axle shaft - Inner carrier (blue) - Sprocket segments and hub (brown) Rotasi poros gandar luar dan roda gigi matahari bagian dalam menyebabkan roda gigi planet bagian dalam berputar. Ring gear stasioner. Saat roda gigi bagian dalam berputar di sekitar bagian dalam ring gear, pembawa bagian dalam berputar. Pembawa bagian dalam terhubung ke gigi sun luar oleh splines. Saat pembawa bagian dalam berputar, roda gigi luar matahari menyebabkan roda gigi planet luar berputar. Roda gigi luar planet bergerak di sekitar bagian dalam ring gear menyebabkan carrier luar dan hub berputar. Daya diarahkan ke segmen sproket dan trek. Semua komponen di final drive terciprat pelumas dari oli di dalam final drive. PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



POWER TRAIN



2-26



The brake components (dark yellow) consist of the following: - Brake housing - Discs and plates - Piston - Belville spring - Spool Rem hanya digunakan untuk menghentikan mesin dan tidak membantu dalam memutar. Mata air Belville digunakan untuk mengompresi pelat dan cakram, dan oli tekanan dari katup kontrol rem digunakan untuk melepaskan rem dengan mengompresi mata air Belville melalui piston rem. Ketika pedal rem servis ditekan, pelat dan cakram menghentikan rotasi poros luar, komponen final drive, dan segmen hub dan sproket. Mesin akan berhenti total. Jika transmisi berada dalam persneling, konverter akan berada dalam kondisi mogok. Tuas rem parkir terhubung ke katup rem parkir. Di PARK, katup memblokir oli tekanan ke piston rem. Ketika tuas dipindahkan ke bawah, katup rem parkir mengarahkan oli tekanan ke piston rem yang menekan pegas Belville dan melepaskan rem parkir. The steering differential and planetary components (purple) consist of the following: - Housing - Bevel gear - Steering pinion - Two ring gears - Planet gears - Two carriers - Two sun gears Sisi kiri diferensial menerima daya transmisi dari poros gandar tengah. Selama kemudi, daya juga disuplai oleh motor kemudi melalui pinion kemudi dan bevel gear. Pinion kemudi dan roda gigi bevel terhubung ke rumah yang dibentang ke ring gear. Roda gigi planet terhubung ke pembawa, yang condong ke poros poros luar. Hub (abu-abu) stasioner dan menggunakan segel Duo-cone untuk menjaga kontaminan keluar dari perumahan.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



POWER TRAIN



2-27



Two plugs are installed in both the right (shown) and left brake housings: - Right side brake lube pressure (1). - Right side brake release pressure (2). Pada HIGH IDLE dengan rem DIRELEASED, tekanan pelumasan rem sekitar 205 kPa (30 psi). Pada HIGH IDLE dengan rem yang DIAKTIFKAN, pelumasan rem sekitar 150 kPa (22 psi). CATATAN: Pada rumah rem kiri colokan dibalik.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



POWER TRAIN



2-28



Ilustrasi ini menunjukkan operasi spool shuttle selama pengaktifan dan pelepasan rem. Piston rem dan spool antar-jemput ditunjukkan dengan warna kuning. Oli bertekanan dari katup rem parkir melepaskan rem dengan menggerakkan piston ke kanan. Pergerakan piston menyebabkan spool shuttle bergerak ke kanan dan membatasi aliran oli pelumas ke rem. Pembatasan ini memiliki efek pada aliran pelumas yang mirip dengan lubang. Tidak diperlukan aliran pelumas maksimum ke rem saat rem dilepas. Selama pengereman rem, pegas Belville menggerakkan piston ke kiri. Oli pelumas kemudian dapat memindahkan spool antar-jemput ke kiri dan sepenuhnya membuka lintasan ke rem. Aliran pelumas sekarang maksimum.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



POWER TRAIN



2-29



Di bagian kiri depan drive pompa adalah tap tekanan (panah) untuk menguji tekanan pelumasan ke roda gigi drive pompa. Pada LOW IDLE dengan rem yang DIAKTIFKAN, tekanan harus sekitar 310 kPa (45 psi). Pada TINGGI IDLE dengan rem ENGAGED, tekanan harus sekitar 620 kPa (90 psi).



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



POWER TRAIN



2-30



DIFFERENTIAL STEER MECHANICAL OPERATION Traktor steer diferensial tidak dilengkapi dengan kopling kemudi tetapi memiliki diferensial kemudi, pompa hidrolik, motor kemudi hidrolik, dan kontrol kemudi. Diferensial kemudi memiliki dua input daya: input kecepatan dan arah (FORWARD dan REVERSE) dari transmisi dan input kemudi (KIRI dan KANAN) dari motor hidrolik. Diferensial kemudi menggunakan input daya motor hidrolik untuk meningkatkan kecepatan satu track dan mengurangi kecepatan track lainnya. Perbedaan kecepatan lintasan yang dihasilkan mengubah traktor. Diferensial kemudi terdiri dari planet pengarah, planet penggerak, dan planet pengimbang. Kode warna dalam ilustrasi ini menunjukkan berbagai komponen. Pinion, poros gigi bevel, dan penggerak planetary drive berwarna merah. Bevel gear shaft condong ke penggerak planetary drive. Selama belokan, pinion untuk motor hidrolik menggerakkan roda ring planetary steer.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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POWER TRAIN



2-31



Pinion motor hidrolik dan gear ring planetary steer berwarna oranye.



Poros tengah menghubungkan roda gigi matahari untuk ketiga planet.



Roda gigi matahari dan poros tengah berwarna biru.



Roda gigi planet untuk ketiga planet berwarna kuning.



Poros gandar tengah condong ke planetary steer dan planetary equalizer. Juga, pembawa planetary steer terhubung langsung ke drive ring planetary drive. Komponen-komponen ini berwarna hijau.



Gear ring planet penyetaraan dibaut ke housing rem kanan dan tetap diam. Planet penyamar adalah abu-abu.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



POWER TRAIN



2-32



Ilustrasi ini menunjukkan aliran daya melalui sistem kemudi diferensial selama operasi



garis lurus (FORWARD atau



REVERSE). Dalam kondisi ini, motor kemudi hidrolik tidak berputar. Karena motor kemudi hidraulik tidak berputar, pinion kemudi dan kemudi cincin planetary stasioner (abu-abu) dan transmisi menyediakan semua aliran daya melalui sistem. Transmisi mengirimkan daya melalui transfer gear, pinion, bevel gear, dan poros gear bevel ke penggerak planetary drive. Pada titik ini, daya terbagi menyebabkan perpecahan torsi.



Sebagian besar torsi melewati drive ring planetary drive ke pengangkut planetary steer. Dari pengangkut planetary steer, tenaga yang dihasilkan ditransmisikan ke penggerak akhir kiri melalui gandar luar kiri.



Torsi yang tersisa dari penggerak planetary drive ditransmisikan ke gear planetary matahari yang menyamakan melalui drive planetary drive dan poros tengah.



Roda gigi planet yang menyamakan kedudukan melipatgandakan torsi dari roda gigi matahari dan mengirimkan tenaga yang dihasilkan melalui poros luar kanan ke penggerak akhir yang tepat.



Efek dari operasi ini adalah bahwa gandar luar kiri dan kanan berputar dalam arah yang sama dengan besarnya daya yang sama dan mesin, oleh karena itu, melacak dalam garis lurus.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



POWER TRAIN



2-33



Selama belokan, baik transmisi dan motor hidrolik memberikan input ke sistem kemudi diferensial dengan transmisi yang memasok sebagian besar daya ke sistem.



Daya input transmisi dikirim ke gandar luar dengan cara yang sama seperti selama operasi garis lurus. Input motor hidrolik menentukan arah putaran dan radius putaran. Rpm dari motor hidrolik mengontrol radius putaran (semakin tinggi rpm, semakin kecil radius putaran) dan arah rotasi membentuk arah putaran.



Selama MENGHIDUPKAN KIRI ke arah FORWARD, motor hidrolik mengirimkan daya melalui roda cincin planetary steering dan roda gigi planet ke roda gigi matahari.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



POWER TRAIN



2-34



Input dari motor hidrolik memiliki dua efek pada sistem: 1. Efek pertama adalah kecepatan ketiga gigi matahari dan kecepatan gandar tengah meningkat menyebabkan kecepatan kanan gandar luar meningkat. 2. Efek kedua adalah bahwa gerakan relatif dari roda gigi matahari dan roda gigi planet di kemudi dan planet penggerak menyebabkan roda cincin planet penggerak, pembawa planetary kemudi, dan gandar luar kiri untuk melambat. (Gerakan relatif ini disebabkan oleh fakta bahwa pembawa planet penggerak berputar pada rpm konstan.) Penurunan kecepatan gandar luar kiri sama dengan peningkatan kecepatan gandar luar kanan. Untuk membuat TURN KANAN, arah motor hidrolik berlawanan dengan arah untuk TURN KIRI. Motor sekarang mengirimkan tenaga ke pembawa planetary steering yang menyebabkan peningkatan kecepatan pembawa planetary steering, drive ring planetary gear, dan gandar luar kiri. Secara bersamaan, ketiga gigi matahari, poros tengah, dan poros luar kanan melambat. Penurunan kecepatan gandar luar kanan sama dengan peningkatan kecepatan gandar luar kiri.



CATATAN: Selama operasi normal, sistem ini tidak menyediakan kapabilitas "putaran poros". INSTRUCTOR NOTE: For more information about differential steering operation, see STMG 547 "D8N Track-type Tractor—Power Train and Implements" (Form SESV1547).



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



POWER TRAIN



2-35



This slide shows the advantage the two pump system has over the one pump system. The former system had a larger turning radius when the operator made a turn while using an implement. The two pump system provides the operator with a tighter turn radius with or without using the implements.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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POWER TRAIN



2-36



Differential Steering System This block diagram shows the steering and implement hydraulic system. The two systems are functionally separate, but they are connected at two points. Charge pressure is used to move the ripper diverter valve, and the implement pump output is sent to the bypass and pressure control group to supplement charge flow if the pressure decreases below a specified value. A single quick-drop valve is used for both lift cylinders.



The various color codes which will be used in this section of the presentation to identify oil flow and pressures are:



Red



- Drive loop or high pressure



Red and White Stripes



- First reduction of supply pressure



Red Dots



- Second reduction of supply pressure



Blue



- Blocked oil



Orange



- Charge pressure



Orange and White Stripes



- Pilot pressure



Orange Dots



- Pump control pressure



Green



- Tank or case drain oil



Yellow



- Activated valve envelopes or moving parts



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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POWER TRAIN



2-37



The steering pump is controlled by a pilot valve connected to the bottom of the steering tiller. The valve contains two pressure reducing valves that convert charge pressure to pilot pressure. The two pressure taps are for the right (1) and left (2) steer pilot pressures. The hoses (3 and 4) are for the return oil and charge pressure, respectively.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



POWER TRAIN



2-38



The steering pump circuit is a closed loop hydraulic system which includes an axial piston pump with over-center capability. The steering pump contains the charge pump (1), the pressure compensator (cutoff) valve (2), the charge pressure relief valve (3), and the right and left crossover relief and makeup valves (4 and 5).



The charge pump (1) is contained in the end of the steering pump. The pump control spool (6) and the pump control piston (7) use charge pressure oil to move the swashplate for left and right turns.



The pressure taps on the top of the pump control piston are for troubleshooting steering problems and adjusting the neutral setting of the steering pump.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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POWER TRAIN



2-39



The bypass and pressure control group (arrow) is a collection manifold for the charge pressure and cooling circuit of the steering system. The control valve group is mounted on the transmission case directly to the right of the steering motor.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



POWER TRAIN



2-40



The bypass and pressure control group directs oil from the charge pump to the filter, the pressure control valve and then to the cooler. The oil then returns to the pressure control valve and enters the steering closed loop. The valve group also contains the cooler and cold oil bypass valves and controls the makeup functions for the steering charge pump oil circuit.



The three pressure taps are: - Steering pump case drain (1) - Charge pump discharge pressure (2) - Charge pump relief pressure (3)



The pilot and ripper diverter valve use charge oil from the upstream side of the cooler. This pressure is lower than the charge pump discharge pressure but higher than the charge pump relief pressure.



The check valve (4) is used to block oil flow from the steering circuit into the implement circuit. If the steering system charge pressure decreases below 2000 kPa (290 psi), oil from the implement pump flows through the check valve to replenish the charge circuit.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



POWER TRAIN



2-41



The hydraulic tank (1) serves as a reservoir for the steering and implement hydraulic oil. The hydraulic tank contains a 165 micron screen filter for the implement circuit, while the steering system return oil is filtered by the case drain reverse flow element (2). The return filter and the bypass valve, the fill strainer, the Electronic Monitoring System temperature switch, the oil level sight glass, the vacuum breaker relief valve, and the ecology drain are additional features of the tank. The tank holds 70 L (18.5 gal.) of oil which represents a 21% increase in oil capacity from the former model. The steering charge circuit oil filter (3) is located behind a hinged access door on the right side of the machine and in front of the tank. The filter has a spin-on canister, an oil pressure tap (6), an oil sampling port (7), a bypass switch (5), and a temperature override switch (4). If either system overheats, the Electronic Monitoring System will register a Category 3 Warning.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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POWER TRAIN



2-42



The drain plug for the hydraulic tank is located below the tank directly above the right track. To drain the oil, remove the cover (arrow) to access the ecology drain valve. Install a 25.4 mm (1 in.) pipe with 1 11 1/2 NPTF threads to unseat the valve (not shown) to start the flow of oil. To stop the flow of oil, remove the pipe and a spring will close the valve.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



POWER TRAIN



2-43



The hydraulic oil cooler (1) is an air-to-oil design located on the front left side of the engine directly behind the radiator guard. The charge pump oil is filtered and sent through the cooler to the steering pump. The cooler has a heat rejection rating of 14 kW (13 Btu/sec.) at 57 Lpm (14.8 gpm) and dissipates the heat from the steering and implement systems. Located at the bottom of the cooler is the cooler pressure tap (2). The bypass and pressure control valve contains the cooler bypass relief valve. This valve is set to open and bypass charge pump oil around the cooler if the pressure differential is higher than 345 kPa (50 psi). The cooler is the same part number used in the previous model, but the system pressure is higher, approximately 2500 kPa (365 psi).



Steering System Operation This schematic shows the components and conditions of the steering system with the engine started and the dual twist tiller in NEUTRAL (no turn).



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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2-44



The major components of this system are: the steering pump, the steering motor, the pilot valve, the bypass and pressure control group, the steering charge circuit filter, and the cooler. Flow to the closed loop steering system is supplied by an axial piston pump with over-center capability. Components included in the pump are: Charge pump : Fills the system with oil during start-up and provides cool oil for the drive loops and steering pilot valve. This oil is called "charge pump discharge pressure" and is 345 to 550 kPa (50 to 80 psi) higher than charge pressure. Pressure compensator (cutoff) valve: When the pressure in either side of the loop reaches 40000 kPa (5800 psi), this valve destrokes the pump by draining the charge pressure sent to the pump control spool to move the pump control piston. Charge pressure relief valve : This valve limits the charge pressure to 2500 kPa (365 psi) after the charge pump oil is filtered and cooled. Charge oil is then sent to the drive loop, pilot valve, ripper diverter valve, and pump control piston. Crossover relief and makeup valves: Each side of the drive loop has a valve that limits the pressure spikes and also directs the charge pressure through the internal check valve to fill the low pressure side of the loop. Pump control spool and pump control piston:



Oil pressure from the pilot valve moves the



spool a small distance and directs charge pressure to either end of the pump control piston. As the pump control piston moves and changes the angle of the swashplate, the feedback link of the pump control spool follows up and maintains the correct pressure to the pump control piston for the amount of steering flow requested. In the NEUTRAL (or no turn) position, a small amount of pressure is present on both ends of the pump control piston. Other components included in the steering system are: Pilot valve: Contains two pressure reducing valves which control the displacement of the steering pump. Pressure from the pilot valve is set to begin upstroking the pump at 600 kPa (87 psi) and provide maximum displacement at 1800 kPa (261 psi).



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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POWER TRAIN



2-45



Steering motor with flushing valve : Uses flow from the steering pump to turn the motor clockwise or counterclockwise for either left or right turns. A flushing valve that meters oil from the low pressure side of the loop is contained in the port plate to help keep the motor cool during operation. Steering charge circuit filter: Spin-on filter housing with a bypass valve rated at 175 kPa (25 psi). The normally open bypass switch is installed in the inlet passage and held closed by the bypass valve. When the bypass valve opens to bypass oil flow around the filter element, the switch opens and the Electronic Monitoring System provides a Category 3 Warning. The alert indicator and action lamp flash and the action alarm sounds. Bypass and pressure control group : This valve group serves as a collection manifold for the charge pressure and cooling circuit of the steering system. The valve group directs oil from the charge pump, through the filter and the cooler, and then back to the steering pump. The bypass and pressure control group also provides the oil cooler bypass and makeup functions for the charge circuit.



Components included in the bypass and pressure control group are: Cold oil bypass valve: This valve protects the charge circuit and opens at 3200 kPa (460 psi) when the oil is cold. Cooler bypass valve: This valve protects the cooler from differential pressures higher than 345 kPa (50 psi). Pressure reducing and check valve: If the charge pump pressure decreases below 2000 kPa (290 psi), oil from the implement pump flows through the check valve and the pressure reducing valve to replenish the charge circuit. Cooling orifice: As the case drain oil from the steering pump flows into the pressure control group, the flow is restricted and directed into the steering motor for additional cooling.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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POWER TRAIN



2-46



The pilot signal to the pump control spool originates at the pilot control valve. This valve contains two pressure reducing valves that use charge pressure for the source of oil. The pump swashplate angle is directly related to the amount of oil pressure sent from the pilot valve to the pump control spool. The pump control spool acts as a servo valve to direct charge pressure oil in and out of the pump control piston to mechanically move the swashplate. A feedback lever which connects the pump control piston to the pump control spool helps maintain pump flow for any given pilot signal.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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POWER TRAIN



2-47



This slide shows a close view of the steering pump in the NEUTRAL (no turn) condition. Charge pressure oil from the bypass and pressure control group enters the steering pump and flows to the charge pressure relief valve, the right and left crossover relief valves, and the pressure compensator valve. Charge oil also flows through the orifice to the pump control spool and pressurizes both ends of the pump control piston. After the pump control piston is pressurized, a drain passage in the pump control spool constantly bleeds a small amount of charge pressure oil to the tank. Most of the charge pressure oil flows to the tank through the charge pressure relief valve.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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POWER TRAIN



2-48



In the NEUTRAL (no turn) condition, charge pressure is prevented from flowing through the steering motor because the flushing valve is centered. The flushing valve permits oil to flow from the low pressure side of the loop through the valve when a right or left turn is initiated. Two sources of cooling oil are provided to the motor: The first is the internal flushing valve in the port plate and the second is the steering pump case drain oil that is routed through the bypass and pressure control group to the motor. On many systems, a case drain pressure test for the steering motor is a good diagnostic check, but with the two sources of flow going through the motor, a pressure tap is not provided.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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2-49



The flushing valve is contained within the port plate of the steering motor. This valve is designed to bleed off approximately 4 Lpm (1 gpm) of flow from the motor when the steer pressure increases to 2500 kPa (262 psi). When the pressure in the drive side of the loop is 2500 kPa (262 psi) higher than the return side, the higher pressure moves the pin and allows oil to flow through the port plate into the motor case. This oil combines with the steering pump case drain oil for more cooling. The combined flow is directed through the bypass and pressure control group to the tank.



NOTE: Longitudinal slots are machined into the round pin in the port plate.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



POWER TRAIN



2-50



This schematic shows the operation of the steering system when the operator moves the dual twist tiller for a LEFT TURN. The dual twist tiller moves linkage that causes the left steering plunger to retract and send pilot oil to the pump control spool in the steering pump. Pressure from the pilot valve is set to begin upstroking the pump at 600 kPa (87 psi) and provide maximum displacement at 1800 kPa (261 psi).



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



POWER TRAIN



2-51



This slide shows the steering pump during a LEFT TURN. The pilot valve sends oil to the left end of the pump control spool which directs charge pressure oil to the pump control piston. The control piston mechanically moves the swashplate to the desired pump angle. Steering pump flow is then sent to the steering motor which provides a mechanical input to steer the machine. As the pressure increases in the drive side of the steer loop, the left crossover relief valve closes. The right crossover relief valve opens and lets charge pressure oil flow into the return side to provide makeup oil to replenish leakage in the loop. During a stall condition, the pressure spike which occurs in the drive side of the loop is relieved by the crossover relief valve and sent to the return side of the loop. If the operator continues to hold the tiller in the same position, the pressure compensator valve, which is set at 40000 kPa (5800 psi), opens and drains the oil sent by the pump control spool to the pump control piston. The piston causes the swashplate to move toward a minimum angle and maintain maximum pressure. PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



POWER TRAIN



2-52



NOTE: Charge pressure (orange) and low pressure return oil (red and white stripes) are equal. The respective flows are shown this way to help keep the circuits separate. This slide shows the steering pump during a LEFT TURN. The left crossover relief valve is closed, and the drive loop pressure (red) is sent to the steering motor. The right crossover relief valve is in the makeup mode, allowing charge pressure oil (orange) to replenish the return side of the loop. If a pressure spike occurs in the drive side of the loop, the left crossover relief valve opens and directs excess oil into the return side of the loop. The pressure compensator valve destrokes the pump if the pressure exceeds the valve setting by draining the charge pressure oil (orange) that is sent to the pump control spool and the pump control piston. The orifice plug just above the left crossover relief valve helps maintain the charge pressure when the pressure compensator drains the charge oil to the pump control spool and the pump control piston. The charge pressure relief valve limits the charge pressure (orange) used in the steering system and continually drains the excess oil that is not required in any of the circuits.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



POWER TRAIN



2-53



The high pressure oil sent to the steering motor causes the motor to rotate and provide a mechanical input to the steer planetary in the bevel gear case. The high pressure oil moves the flushing valve. When the valve moves, low pressure (return) oil flows into the motor housing and then to the bypass and pressure control group.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



POWER TRAIN



2-54



The pump control spool uses pilot oil (orange and white stripes) to control the amount of charge pressure oil (orange dots) that is sent to the pump control piston. The movement of the pump control spool is approximately 2.00 mm (.078 in.) in each direction. This spool constantly meters the charge oil to maintain the correct pressure at the pump control piston and the correct swashplate angle. This slide shows the pilot valve moved to the LEFT TURN position. Pilot pressure is proportional to the amount of lever movement that is directed to the upper end of the pump control spool. As the spool moves down, a passage opens and sends charge pressure oil to the upper end of the pump control piston. At the same time, the spool control arm shifts the left lever arm. This movement increases the tension of the compression spring proportional to the force created by the pilot oil from the pilot valve. The lever arms and the feedback lever pivot on the eccentric screw (pivot point). An adjustment screw can be used to adjust the center position of the spool.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



POWER TRAIN



2-55



Charge pressure oil directed to the upper end of the pump control piston compresses the large springs and moves the pump control piston down. As the pump control piston moves, the feedback lever pivots at the pivot point and the stop on the feedback lever opens the right lever arm to cause more compression on the spring. The spring force moves the spool back toward the neutral position. As the spool moves toward neutral, the opening to the passage for charge pressure oil to the pump control piston is reduced. The charge pressure at the upper end of the piston is decreased and the large springs move the swashplate toward minimum angle to maintain the turn. If the operator stalls the steer motor, the pressure compensator valve destrokes the pump by bleeding off charge pressure oil at the pump control piston. The large springs in the pump control piston move the swashplate toward minimum angle to reduce pump output. This condition occurs automatically and prevents the operator from stalling the steering system at maximum flow. If the operator holds the tiller at the full left turn position with the brakes engaged, the crossover relief valve will limit the pressure spike and the pressure compensator will bleed the charge pressure oil from the upper end of the control piston to decrease the angle of the swashplate. Pump flow is at minimum, but the system pressure is at the setting of the pressure compensator.



NOTE: In NEUTRAL (no turn), the pump control spool (if centered) will send equal pressure to each end of the pump control piston. Since 600 kPa (87 psi) is needed to move the pump control piston, a difference of more that 600 kPa (87 psi) will cause the machine to move when the parking brake lever is moved to the released position. The adjustment screws on the pump control spool are used to adjust the pressures on each end of the pump control piston. If the spool needs adjustment, follow the procedure in the Service Module Supplement (Form SENR4983). Loosening and tightening the locknuts will change the center position of the pump control spool. The small adjustment screws on both ends of the pump control piston are not adjustable and have factory installed tamper proof caps. Any attempt to adjust the screws will cause the valve to react differently to pilot oil directed from the tiller lever. Replace the valve if the caps have been tampered with and if the valve is damaged.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



POWER TRAIN



2-56



This slide shows a side view of the steering pump. The following components are visible: the right and left crossover relief valves, the charge pump, the pump control valve, the feedback lever, the pump control piston, the swashplate, and the pistons.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



POWER TRAIN



2-57



The main purpose of the bypass and pressure control group is to direct charge pump discharge oil through the steering charge circuit filter and cooler. After the oil has been filtered and before it is cooled, the charge pressure oil is available for the ripper diverter valve and steering pilot valve. After the oil goes through the cooler, the flow is directed to the steering pump control spool and to the drive loop for makeup oil. The cold oil bypass valve protects the filter and charge pump during start-up and the cooler bypass valve protects the cooler. The cold oil bypass valve is set to open at 3200 kPa (460 psi). The cooler bypass valve will open when the pressure differential is 345 kPa (50 psi). The charge circuit makeup valve is a pressure reducing valve that directs implement pump oil to the charge circuit if the charge pressure decreases below 2000 kPa (290 psi).



The cooling orifice restricts the flow of steering pump case drain oil. This restriction forces some of the steering pump case drain oil through a line to the steering motor case. This oil adds to the oil from the steering motor flushing valve for cooling and lubrication of the steering motor.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



UNDERCARRIAGE



3-1



BAB 3 UNDERCARRIAGE



The D8R suspended undercarriage is designed to absorb impact loads to reduce the shock loads transferred to the machine frame. Two types of undercarriage are available: a suspended undercarriage (shown) that provides up to 15% more ground contact and a non-suspended undercarriage for applications involving moderate impact or highly abrasive materials. The main components of the undercarriage are: the front idler (1), the front roller frame (2), the rear roller frame (3), the pivot shaft (4), the rear idler (5), the track (6), the major bogies (7), the minor bogies (8), the cover plate (9) for the track adjuster, and the cover (10) for the guides. The pivot shaft connects the right and left rear roller frames and transmits the ground shocks directly to the main frame rather than through the power train components. The roller frames can oscillate PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



UNDERCARRIAGE



3-2



around the pivot shaft. The equalizer bar (not shown) is an additional component of the undercarriage. The equalizer bar is pinned in the center of the tractor and can rotate around the center pin joint. The equalizer bar connects the two rear track roller frames and controls the degree that the roller frames can oscillate around the pivot shaft. The front roller frame slides inside the rear roller frame. Pumping grease into a cylinder inside the rear roller frame increases the recoil spring tension. A key and slot mechanism in the front and rear track roller frames allows the front roller frame to slide in and out of the rear roller frame, but prevents the front roller frame from rotating inside the rear.



To increase track tension, remove the adjusting valve cover plate (9) and add grease through the adjusting valve. To decrease track tension, loosen the relief valve and allow grease to escape. Then, close the relief valve and add additional grease through the adjusting valve.



NOTE: The D8R Operation and Maintenance Manual (Form SEBU6891) shows the correct track adjustment procedure.



The pivot shaft oil can be checked by removing the dipstick (arrow) from the container in the compartment just behind the batteries. The oil level should be maintained to the FULL mark.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



UNDERCARRIAGE



3-3



This slide shows the location of the equalizer bar end pin grease fitting (1). Using a hand operated grease gun filled with 80w90 EP gear oil, fill the joint through the grease fitting until the oil flows from the relief valves (2).



The joint can be filled with 5P0960 Multipurpose Molybdenum Grease (MPGM) if current maintenance practices make filling with EP oil difficult. The joint is filled at the factory with EP oil due to its greater load carrying capabilities and lubricating qualities. The combination of EP oil and MPGM grease will not be detrimental.



The equalizer bar has limited slip end pin seals (3). NOTE: The D8N can be modified to accept these improvements if the machine is updated to reduce oscillation, and the equalizer bar is modified to provide pressure relief during the grease fill



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



IMPLEMENT HYDRAULIC SYSTEM



4-1



BAB 4 IMPLEMENT HYDRAULIC SYSTEM



The implement hydraulic system consists of a variable displacement pump, three control valves with an inlet manifold, and a single quickdrop valve. The steering and implement systems are connected at one point. The implement pump output is sent to the bypass and pressure control group to supplement the steering charge pump if the discharge pressure decreases below a specified value.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



IMPLEMENT HYDRAULIC SYSTEM



4-2



The hydraulic tank serves as a reservoir for the implement and steering hydraulic oil and is located on the right fender. The oil cap and fill tube (1) are located on the top of the tank. Inside the fill tube is a fine mesh screen which removes large particles of dirt or foreign material from the oil as the tank is filled. A vacuum breaker/relief valve (2) is also located on the top of the tank. The oil level sight gauge (3) on the front of the tank permits an easy check of the hydraulic system oil level. Always clean the sight gauge to be sure the oil level is visible. Dirt and stains on the glass frequently give the appearance of a full tank.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



IMPLEMENT HYDRAULIC SYSTEM



4-3



The implement hydraulic system is load sensing and pressure compensated with a variable displacement slipper-type pump (1). The pump is very similar to many other models in the Caterpillar equipment line. Mounted on the left side of the pump are the flow compensator valve (2) and the pressure compensator valve (3). The implement hydraulic pump maintains a low standby pressure between 2100 kPa (305 psi) and 3600 kPa (520 psi). Margin pressure is 2100 kPa (305 psi) and high pressure cutoff is 26200 kPa (3800 psi). Contained in the inlet manifold of the implement valve stack are the main relief valve and the charging valve. The main relief valve protects the system from pressure spikes over 27000 kPa (3900 psi). The charging valve restricts return flow to the tank that helps prevent cavitation in the cylinders.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



IMPLEMENT HYDRAULIC SYSTEM



4-4



The implement control valve consists of three parallel valve sections: ripper, dozer lift, and dozer tilt. The ripper control valve is standard on all machines even if the machine is purchased without a ripper. The ripper hardware may be added in the future along with the ripper diverter valve.



Pressure taps are provided on the inlet manifold for signal oil (1) and pump discharge (2). By using these pressure taps, margin pressure, low pressure standby and high pressure stall can be tested. The inlet manifold includes the main relief valve (3) and the return oil charging valve (4). The main relief valve is set at 27000 kPa (3900 psi), which is 2750 kPa (400 psi) higher than the pressure compensator (cutoff) valve. The main purpose of the main relief in the system is to eliminate pressure spikes. If the system is in a stall condition, the pressure cutoff valve will cause the implement pump to destroke toward a minimum angle. The charging valve restricts the cylinder return oil flow to the tank. This valve keeps oil pressure in the cylinder return oil passage of the implement control valves and is used with the makeup valves to prevent cavitation in the cylinders. A typical function when the charging valve assists PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



IMPLEMENT HYDRAULIC SYSTEM



4-5



the makeup valve and the quick-drop valve for the lift cylinders is when the dozer control lever is moved to the full lower position (quick-drop) and the dozer is lowered rapidly.



The supply line (5) goes to the bypass and pressure control group and connects to the external check valve. This line supplies implement pump oil to the internal pressure reducing valve in the valve group. The pressure reducing valve in the bypass and pressure control valve provides implement pump oil to supplement the steering charge pump discharge oil if the charge pressure decreases below 2000 kPa (290 psi). Implement system pressure will be felt in this line at all times.



NOTE: To connect the 1U5796 Differential Pressure Gauge Group to these two pressure taps, remove only the floor plate in the operator's station. Both hydraulic hose couplings can be connected to the pressure taps by laying down on the outside of the right side of the operator's station and using the right hand to secure them. The operator's seat and seat plate need not be removed for this test.



The threaded gland lift cylinders (1) have built-in bypass plungers that prevent high pressure loads at either end of the stroke. The single quickdrop valve (2) replaces the former quick-drop valves which were located on the head end of each lift cylinder.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



IMPLEMENT HYDRAULIC SYSTEM



4-6



The D8R is available with single or dual tilt cylinders (arrows). If the machine is equipped with a single cylinder, the left cylinder is replaced with a brace. The tilt control valve will operate either the single or dual tilt cylinder arrangement. The dozer tilt cylinders have the conventional bolt-on head design. This view of the rear of the machine shows the main components of a single shank ripper. The



visible components include: the carriage (1), the shank and tooth assembly (2), the ripper frame (3), the lift cylinders (4), the tip cylinders (5), and the diverter valve (6). NOTE: The ripper shank and tooth assembly is mounted in the machine travel position. For the ripper to be used, the shank must be mounted in the carriage with the tooth pointing toward the ground. The machine can also be equipped with a multi-shank ripper for other ripping applications.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



IMPLEMENT HYDRAULIC SYSTEM



4-7



The optional ripper diverter valve group (2) is mounted on the rear of the machine. The control lever has been redesigned to accommodate the diverter valve switch (1). When the switch is depressed and the lever is moved left and right, the ripper tip will move in or out. Releasing the switch and moving the lever left and right will raise or lower the ripper. The switch activates a solenoid on the ripper diverter valve that sends steering system charge pressure oil to move the spool in the diverter valve. The diverter valve permits a single ripper control valve to be used for both operations. The single shank ripper can be equipped with an optional hydraulically operated pin puller (5). The pin puller control valve (4) allows the operator to release and engage the pin for the ripper shank with the toggle switch (3) without leaving the operator's station. Oil for operation of the pin puller circuit is supplied by the power train hydraulic system.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



IMPLEMENT HYDRAULIC SYSTEM



4-8



Implement System Operation This diagram shows the hydraulic system with all the implements in HOLD.



Oil is sent from the common steering and implement



hydraulic tank to the variable displacement, piston-type pump. Supply oil is directed to the closed-center control valves. Return oil and pump case drain oil are sent to the tank.



When a control lever is moved, oil from the implement control valve is directed to double acting implement cylinders.



The signal network line (orange) is in series with each control valve and passes through each valve body. The signal network terminates at the pump control valve. When an implement is activated, a signal is generated by the work port load. This signal is sent through the signal network. A resolver network inside the implement valves consists of a series of check valves which compare the signals from the implements and send the highest signal to the pump control valve.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



IMPLEMENT HYDRAULIC SYSTEM



4-9



This schematic shows the components and conditions in the implement system with the engine started and the implements in HOLD.



The major components in this system are: the implement pump, the inlet manifold, the ripper, lift and tilt control valves, the quick-drop valve, and the ripper diverter valve.



Three changes have occurred from the D8N: a single quick-drop valve, an electrically actuated ripper diverter valve, and the flow control spool in the control valve is solid rather than hollow. In addition to the implement oil being used to move the cylinders, it also is sent to the bypass and pressure control group to supplement the charge pump if the discharge pressure decreases below 2000 kPa (290 psi). The ripper diverter valve uses steering charge pressure to move the ripper diverter spool when the operator selects the RIPPER TIP or LIFT functions. PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



IMPLEMENT HYDRAULIC SYSTEM



4-10



Implement Pump Shown here is the pressure compensator valve used on the implement pump. Two spools are installed in the valve: 1. The flow compensator (or margin) spool is on the left. This valve controls margin pressure and low pressure standby. Margin pressure is set at 2100 kPa (305 psi) above the signal pressure. Low pressure standby is approximately 3000 kPa (435 psi). If this pressure is below 2100 kPa (305 psi) or above 3600 kPa (520 psi), margin pressure should be checked. Adjusting the margin pressure to specification allows the standby pressure to be maintained within specification. 2. The pressure compensator (or cutoff) spool (on the right) controls the stall pressure. The valve is set at 24100 kPa (3500 psi).



NOTE: Each spring has an individual adjustment screw.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



IMPLEMENT HYDRAULIC SYSTEM



4-11



When the engine is OFF, the bias spring holds the swashplate at maximum angle.



When the engine is started, the pump drive shaft starts to rotate. Oil is drawn into the piston bores. As the piston and barrel assembly rotates, the oil is forced out into the system.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



IMPLEMENT HYDRAULIC SYSTEM



4-12



When no flow is demanded from the implements, no signal pressure is generated. System pressure (red and white stripes) generated by the pump is called "low pressure standby." The pump produces enough flow to compensate for system leakage at sufficient pressure to provide for instantaneous implement response when an implement is actuated. At machine start-up, the bias spring holds the swashplate at maximum angle. As the pump produces flow, system pressure begins to increase because the flow is blocked at the implement control valves. This pressure is felt under both the margin spool and the pressure cutoff spool. The margin spool moves up against the low spring force and permits system oil to go to the large actuator piston in the pump.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



IMPLEMENT HYDRAULIC SYSTEM



4-13



As pressure in the large actuator piston increases, the large actuator piston overcomes the force of the bias spring and the pressure in the small actuator piston and moves the swashplate to a reduced angle. The large actuator piston moves to the right until the cross-drilled passage in the stem is uncovered. Oil in the large actuator piston then bleeds off to the pump case. At this minimum angle, the pump will produce just enough flow to make up for system leakage. The system pressure at this time is called "low pressure standby" and is approximately 3000 kPa (435 psi).



Low pressure standby is higher than margin pressure. This characteristic is due to a higher back pressure created by the oil which is blocked at the closed-center valves when all the valves are in HOLD. Pump supply oil pushes the margin spool up and further compresses the margin spring. More supply oil then goes to the large control piston and flows through the cross-drilled hole in the stem to the pump case.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



IMPLEMENT HYDRAULIC SYSTEM



4-14



When an implement requires flow, a signal is sent to the pump control valve. This signal causes the force (margin spring plus signal pressure) at the top of the margin spool to become higher than the supply pressure at the bottom of the spool. The spool then moves down, blocks oil to the large actuator piston and opens a passage to drain. Pressure at the large actuator piston is reduced or eliminated, which allows the bias spring to move the swashplate to an increased angle. The pump will now produce more flow. This condition is called "upstroking."



The following conditions can result in upstroking the pump: 1. An implement control valve is activated when the system is at low pressure standby. 2. The control valve directional spool is moved for additional flow. 3. An additional circuit is activated. 4. Engine rpm decreases. In this case, pump speed decreases which causes a decrease in flow and pump supply pressure. The pump must then upstroke to maintain the system flow requirements. NOTE: Signal pressure does not necessarily have to increase for the pump to upstroke. For example, if one implement is activated and is operating at 13800 kPa (2000 psi), the system PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



IMPLEMENT HYDRAULIC SYSTEM



4-15



supply pressure is 15900 kPa (2305 psi) due to the maximum signal pressure of 13800 kPa (2000 psi) plus the margin spring force. Now, if the operator activates another implement at an initial operating pressure of 6900 kPa (1000 psi), the maximum signal pressure is still 13800 kPa (2000 psi), but the supply pressure decreases momentarily to provide the increased flow now needed at the implements. The force at the top of the margin spool (now higher than the force at the bottom of the margin spool) pushes the spool down and allows oil in the pump control to drain. The swashplate angle increases and the pump provides more flow.



As pump flow increases, pump supply pressure also increases. When the pump supply pressure (red) increases and equals the sum of the load pressure plus the margin spring pressure, the margin spool moves to a metering position and the system becomes stabilized. The difference between the signal pressure and the pump supply pressure is the value of the margin spring, which is 2100 kPa (305 psi).



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



IMPLEMENT HYDRAULIC SYSTEM



4-16



When less flow is needed, the pump is destroked. The pump destrokes when the force at the bottom of the margin spool becomes higher than at the top. The margin spool then moves up and allows more flow to the large actuator piston. Pressure in the large actuator piston then overcomes the combined force of the small actuator piston and bias spring and moves the swashplate to a reduced angle. The pump will now produce less flow.



The following conditions can result in destroking the pump: 1. All implement control valves are moved to the HOLD position. The pump returns to low pressure standby. 2. The control valve directional stem is moved to reduce flow. 3. An additional circuit is deactivated. 4. Engine rpm increases. In this case, pump speed increases causing an increase in flow. The pump destrokes to maintain system flow requirements.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



IMPLEMENT HYDRAULIC SYSTEM



4-17



As pump flow decreases, pump supply pressure also decreases. When the pump supply pressure (red) decreases and becomes the sum of load pressure plus margin pressure, the margin spool moves to a metering position and the system stabilizes.



NOTE: Signal pressure does not necessarily have to decrease for the pump to destroke. For example, if two implements are activated with one at 13800 kPa (2000 psi) and the other at 6900 kPa (1000 psi), the system supply pressure is 15900 kPa (2305 psi) due to the maximum signal pressure of 13800 kPa (2000 psi) plus the margin spring force. Now, if the operator returns the implement at 6900 kPa (1000 psi) to HOLD, maximum signal pressure is still 13800 kPa (2000 psi), but the supply pressure increases due to reduced flow needed at the implements. The supply pressure will push the margin spring up and allow more oil to go to the pump control which causes the pump to destroke.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



IMPLEMENT HYDRAULIC SYSTEM



4-18



The pressure compensator (or cutoff) spool is in parallel with the flow compensator (or margin) spool. The pressure compensator limits the maximum system pressure at any given pump displacement. The spool is held down during normal operation by the pressure compensator spring. During stall or when system pressure is maximum, signal pressure is equal to pump supply pressure. The combination of the signal pressure and the margin spring forces the margin spool down. This movement of the margin spool normally opens a passage in the pump control valve for the oil in the large actuator piston to drain and causes the pump to upstroke. However, if the supply pressure is high enough, the pressure cutoff spool is forced up against the spring. This movement of the pressure cutoff spool blocks the oil in the large actuator piston from going to drain and allows supply oil to go to the large actuator piston. The increase in pressure allows the large actuator piston to overcome the combined force of the small actuator piston and bias spring to destroke the pump. The pump is now at minimum flow and pump supply pressure is at maximum. This condition is maintained for a single implement in a stall condition.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



IMPLEMENT HYDRAULIC SYSTEM



4-19



This system also incorporates a main relief valve located in the inlet manifold. The pressure cutoff spool can be adjusted in the machine to destroke the pump at 24100 kPa (3500 psi). The main relief valve must be removed from the machine and adjusted to 27000 kPa (3900 psi) using the 1U5216 Test Block Manifold. This valve is set higher to limit pressure spikes in the system. When operating two or more implements with one in stall, the pump will produce flow to meet the needs of the other implements operating at a lower work port pressure. In this case, the pump could be producing up to maximum flow while the supply pressure is at the maximum of 24100 kPa (3500 psi).



NOTE: Contained within the pump is a case drain relief valve. If the internal pressure exceeds 170 kPa (25 psi), excess flow will be directed to the inlet of the pump. The relief valve is designed to protect the pump shaft seals.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



IMPLEMENT HYDRAULIC SYSTEM



4-20



The implement valve group consists of an inlet manifold, the ripper, lift, and tilt control valves and an end cover. All machines are equipped with this valve group. Even though the customer may not order the ripper, the valve is included in the stack. The signal line is connected from the inlet manifold to the pump compensator valve. Another line from the inlet manifold sends implement pump oil to the bypass and pressure control group in the steering system. The inlet manifold contains a system relief valve and a charge relief valve. The system relief valve limits pressure spikes and is set higher than the pressure compensator spool. The charge relief valve restricts return oil going to the tank when the pump is not upstroked. This restriction keeps oil pressure in the cylinder return oil passage of the implement control valves. This oil pressure can be used with the makeup valves to prevent cylinder cavitation.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



IMPLEMENT HYDRAULIC SYSTEM



4-21



The dozer lift valve is the second valve in the stack. The lift control valve is a closed-center, manually operated valve controlled through mechanical linkage. The lift valve has four positions: RAISE, HOLD, LOWER, and FLOAT. A centering spring keeps the spool in the HOLD position when the blade lift cylinders are not in use. To operate in the FLOAT condition, the operator must move the control lever forward until the detent balls hold the valve spool. The operator must manually release the lift control lever from the FLOAT position. This slide shows the lift control valve in HOLD. In HOLD, the center axial passage is open to the tank through a drain passage in the valve body. With the engine not running, the spring behind the flow control spool holds the flow control spool to the left. When the operator starts the machine, the pump sends oil through the inlet manifold to the flow control spool, out the throttling slots on the left side of the spool, through the load check valve, and to the main control spool. With the control spool in the HOLD position, oil cannot flow to the cylinders, and oil pressure will begin to increase.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



IMPLEMENT HYDRAULIC SYSTEM



4-22



The increasing pressure in the chamber to the right of the load check valve pushes the flow control spool to the right against the force of the spring. Moving the flow control spool to the right closes the throttling slot on the left side of the spool. Oil can continue to flow to the remaining control valves in the system. In HOLD, pressure at the main control spool is equal to the flow control spool spring. Flow control spool: Receives all the oil flow from the inlet valve group. The flow control spool provides the "pressure compensating" feature of the lift circuit by controlling the maximum pressure drop across the lift control spool. This operation results in a constant implement speed for a given lever displacement. Load check valve: Prevents reverse implement flow when the operator moves a valve from HOLD and system pressure is lower than the cylinder or work pressure. Without the load check valve, the implement would drift down. The load check valve will open to allow supply oil to flow through the control valve when the system pressure is higher than the work port pressure. Resolver:Also called a double check valve. The resolver compares the signal between the valves and sends the highest resolved working pressure to the implement pump flow compensator. Although this slide shows theresolver and signal lines as external components, the resolver is actually inside the control valve, and the signal lines are internally drilled passages.



Main control spool:Controls oil flow to the implement and contains three cross-drilled holes that connect to an axial drilled passage in the center of the control spool. The cross-drilled holes sense work port pressure in both the head and rod ends of the cylinders.



Makeup valve:Allows pressure in the tank to fill voids in the head end of the cylinders during times when cylinder supply pressure decreases below the tank pressure. PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



IMPLEMENT HYDRAULIC SYSTEM



4-23



Orifice: Provides smoother implement operation by delaying the rate that the signal pressure in the flow control spring cavity decreases when the operator changes implement directions. NOTE: The throttling slot near the left end of the flow control spool spool is never completely closed, and the check valve does not completely block oil from reaching the main control spool. A small amount of oil meters through the flow control spool and past the load check valve to maintain a pressure at the main control spool that is equal to the flow control spool spring force. Maintaining pressure at the main control spool improves implement response. If the flow control spool is explained as a pressure reducing valve with a variable spring rate due to changes in signal pressure, the operation of the spool is easier to understand. The spool will limit the maximum pressure difference across the control spool to the value of the flow control spool spring and cylinder pressure to provide constant flow for a given lever displacement. INSTRUCTOR NOTE: For more information about the valve components and operation, refer to STMG 591 "446 Backhoe Loader--Steering and Implement Hydraulic System" (Form SESV1591).



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



IMPLEMENT HYDRAULIC SYSTEM



4-24



As the operator moves the lift control lever to the RAISE position, the control valve spool shifts to the left allowing pump supply to go through the quick-drop valve to the rod end of the cylinders and opens the head end of the cylinders to the tank. The oil will begin filling the rod end of the lift cylinders and begin raising the blade.



Shifting the spool also opens the supply passage drilled in the center of the control valve spool to the rod end port. Pump pressure going to the lift cylinder or pressure from the rod end goes through the drilled passage in the control spool and this signal oil goes to two places. First, the oil travels through the orifice and fills the spring chamber of the flow control spool moving the spool to the left. As the control valve spool shifts to the left, the opening at the throttling slots near the left end of the spool increases so more oil can flow to the work port, while the throttling slots toward the right end of the control valve spool are open to the head end of the cylinder and to the tank. The amount of flow from the pump, combined with the amount of flow the lift work port needs, determines the distance that the flow control valve shifts. Also, the signal oil is sent to the resolver valve. If the lift circuit is producing the highest signal pressure, oil is sent through the manifold to the implement pump flow compensator valve. The pump will then upstroke to maintain the margin pressure, approximately 2100 kPa (305 psi) above the pressure of the signal oil.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



IMPLEMENT HYDRAULIC SYSTEM



4-25



This slide shows the operation of the lift control valve when the operator has selected the dozer LOWER position. The main control spool has shifted to the right opening a passage for supply oil to flow through the quick-drop valve to the head end of the cylinders and a passage for oil from the rod end of the cylinders to return to the tank. The main control spool movement allows the cylinder pressure to become signal oil that is directed to the resolver and the flow control spool spring chamber through the drilled passages in the main control spool. System pressure controls the upstroking of the pump by means of the resolver signal pressure and is the same as described in the dozer RAISE operation.



The passage to the head end of the lift cylinders contains a makeup valve for the lift circuit. When the pressure in the cylinder supply passage decreases below the pressure in the tank, the makeup valve opens and allows return oil from the tank to fill voids in the head end of the cylinders. The makeup valve is needed because the weight of the blade tends to force oil out of the rod end of the cylinders faster than the pump can fill the head end of the cylinders. By including a makeup valve in the head end passage, the possibility of cavitation is greatly reduced. PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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IMPLEMENT HYDRAULIC SYSTEM



4-26



The dozer lower operation can function in two conditions. If the control lever is moved up to 75% of its maximum non-float travel, the valve operates as previously described. However, if the operator continues to move the lever past this position, the quick-drop mode is activated. In FLOAT, detents are used to hold the control valve spool in the FLOAT position. No signal pressure is generated, which keeps the pump destroked. Both the rod and head ends of the lift cylinders are open to the tank, which allows the cylinder rods to move freely in either direction according to the amount and direction of the force on the blade.



NOTE: Quick-drop valve operation will be discussed in greater detail later in this presentation.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



IMPLEMENT HYDRAULIC SYSTEM



4-27



The blade tilt valve is the third valve in the stack. The blade tilt control valve is a closed-center, manually operated valve controlled through mechanical linkage. The valve has three positions: TILT LEFT, HOLD, and TILT RIGHT. The valve has a centering spring to return the spool to the HOLD position when the operator releases the dozer control lever. This slide shows the position of the blade tilt control valve components during TILT LEFT operation. This valve functions basically the same as the blade lift control valve with several differences. When the valve spool shifts to the right, pump supply oil is directed to the head end of the cylinder, and the rod end of the cylinder is opened to drain. The load check valve and the resolver valve operate the same as the dozer lift valve.



One major difference in the blade tilt valve is that no makeup valves are included in either the head end or rod end circuit. Since the pump can supply the necessary amount of oil to fill cylinder without cavitation, makeup valves are not necessary.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



IMPLEMENT HYDRAULIC SYSTEM



4-28



The ripper control valve is the first valve in the stack. The ripper control valve is a closed-center, manually operated valve controlled through mechanical linkage. The valve is used to raise and lower the ripper or to move the ripper shank IN and OUT. Both functions are controlled by the operator through the use of a switch located in the ripper control handle. The switch shifts a spool in the ripper diverter valve which directs oil to the correct circuit. The ripper control valve has a centering spring to return the valve spool to the HOLD position when the operator releases the lever. This slide shows the position of the ripper control valve components in HOLD. This valve functions basically the same as the blade lift control valve with several differences. When the main control spool shifts to the right, pump supply oil is directed to the head end of the ripper lift cylinders or to the head end of the ripper tip cylinders, and the rod end of the cylinders are opened to drain. The load check valve and the resolver valve operate the same as the dozer lift valve.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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IMPLEMENT HYDRAULIC SYSTEM



4-29



The passage to the head ends of either the ripper lift or tip cylinders in the control valve contains a makeup valve. When the pressure in the cylinder supply passage decreases below the pressure in the tank, the makeup valve opens and allows return oil from the tank to fill voids in the head end of the cylinders. The makeup valve is needed because the weight of the ripper tends to force oil out of the rod end of the cylinders faster than the pump can fill the head end of the cylinders. By including a makeup valve in the head end, the possibility of cavitation is greatly reduced.



Quick-drop Valve Shown in this slide is the schematic of the single quick-drop valve that replaces the two quick-drop valves that were mounted on the head end of both lift cylinders in the earlier machines. The valve (arrows) is mounted on top of the engine hood at the front of the machine. In the schematic, components in the quick-drop valve are shown with the dozer blade on the ground. The variable orifice sleeve is the essential component in the valve and functions to create the pressure necessary to move the valve spool to direct rod end oil to the head end in the QUICKDROP mode. PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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IMPLEMENT HYDRAULIC SYSTEM



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Shown in this view are the components of the single quick-drop valve: the orifice sleeve, the plunger, the valve spool, the right and left covers, and the spring.



As shown in the previous slide, the valve components are shown with the dozer blade on the ground. Both the orifice sleeve and the plunger can float in the valve and their positions in HOLD depend on the previous action of the lift control valve: RAISE, LOWER, or FLOAT.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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IMPLEMENT HYDRAULIC SYSTEM



4-31



When the dozer control valve is moved to the RAISE position, supply oil enters the quick-drop valve through the passage on the left and moves the orifice sleeve to the right. The oil then flows out to the rod end of the cylinders. Return oil from the head end of the cylinders enters the valve and flows past the valve spool to the lift control valve. Return oil pressure then enters the passage to the plunger end inside the valve spool and is felt on the right end of the plunger. However, the blade RAISE pressure felt on the left end of the plunger is higher than the return oil pressure and keeps the plunger shifted to the right. Blade RAISE pressure also enters the passage to the right end of the spool. Since the same pressure is felt on the left end of the spool, the spring keeps the spool shifted to the right.



NOTE: The orifice sleeve floats on the valve spool and is kept on the spool by a retaining ring.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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IMPLEMENT HYDRAULIC SYSTEM



4-32



As the operator moves the lever to LOWER the blade (less than 75% of maximum travel), return oil from the rod end of the cylinders enters the quick-drop valve. The return oil flows past the orifice sleeve to the control valve and moves the orifice sleeve to the left against the retaining ring. This oil flow creates a pressure differential across the orifice sleeve. Supply oil (red) from the control valve enters the quick-drop valve and flows past the valve spool to the head end of the cylinders. Supply oil pressure enters the passage to the plunger end and is felt on the right end of the plunger. However, the return oil pressure (red dots) on the left end of the plunger is higher and keeps the plunger shifted to the right. Rod end return oil pressure (red and white stripes) enters the passage to the right end of the spool. This pressure is also felt on the major diameter at the left end of the spool just to the right of the orifice sleeve. In addition, return oil pressure, after the pressure drop across the orifice sleeve, is felt on the minor diameter at the left end of the spool. The net result is that the spool and plunger are kept to the right because of the spring and return pressure. The major diameters of the spool (the effective area at the right end and the effective area just to the right of the orifice sleeve) cancel each other. The pressure on the right end of the spool is not high enough to overcome the spring and return oil pressure on the minor diameter at the left end on the spool.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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IMPLEMENT HYDRAULIC SYSTEM



4-33



When the dozer blade is rapidly lowered to the ground, the control valve lever has been moved more than 75% of the maximum travel, and the quick-drop valve operates in the QUICK-DROP mode. The increased lever travel results in higher cylinder rod end flow and a higher pressure drop across the orifice sleeve. The only difference from the dozer LOWER position is that the pressure drop across the orifice sleeve that is felt on the minor diameter of the right end of the spool overcomes the resistance of the spring, and the spool starts to move. The minimum flow that causes the necessary pressure drop across the orifice sleeve to begin spool movement is referred to as the "trigger point" and occurs at 75% of maximum lever travel. When the spool starts to move, the effective area of the orifice sleeve decreases and the pressure drop increases to shift the spool even farther. The result is that the spool shifts completely to the left.



This



movement connects the rod end of the cylinders to the head end of the cylinders across the slots in the spool. This connection provides even less resistance and the downward blade velocity and flow from the rod ends increase. This connection also provides a "filling" function to minimize the pause time. Some of the oil from the rod ends still flows across the orifice sleeve causing a pressure drop to keep the spool shifted.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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IMPLEMENT HYDRAULIC SYSTEM



4-34



When the blade contacts the ground and stops, flow from the rod end of the cylinders stops. With no pressure drop across the orifice, the spring shifts the spool to the right. After the pump fills the head end of the cylinders (pause time) and the head end cylinder pressure starts to increase, the blade begins to move down. Supply oil pressure (red) enters the passage to the right end of the plunger. Return oil pressure (red and white stripes) from the rod end of the cylinders is felt on the left end of the plunger. This pressure is lower than the oil pressure (red) on the right end of the plunger, and the plunger moves to the left. The pressure drop (red and white stripes) across the orifice sleeve that is felt on the minor diameter of the right end of the spool works to move the spool to the left. However, this movement is resisted by the spring and the supply oil pressure (red) acting on the plunger. Therefore, the spool stays shifted to the right.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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IMPLEMENT HYDRAULIC SYSTEM



4-35



Diverter Valve This slide shows the ripper diverter valve (arrow) with the control lever in the HOLD position. The operator can select any of the four ripper functions (RAISE, LOWER, TIP IN and TIP OUT) by using the control lever, which is equipped with a trigger switch. The trigger switch controls a solenoid on the ripper diverter valve that sends steering charge pressure oil to one end of the valve spool to shift the spool against the springs on the other end. Steering charge pressure at 2500 kPa (365 psi) is the same oil pressure used in the charge circuit for the steering pump and steering pilot valve. The charge pressure test port at the rear of the ripper diverter valve is used to diagnose ripper actuation problems. When the trigger switch is used, the solenoid is energized and charge pressure oil moves the diverter valve spool. Ripper TIP IN or TIP OUT can then be selected.



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IMPLEMENT HYDRAULIC SYSTEM



4-36



The letters below the ripper diverter valve spool relate directly to the ripper TIP IN, TIP OUT, RAISE and LOWER ports. The spool is shown in the solenoid DE-ENERGIZED position. If the operator moves the control lever, the ripper will RAISE or LOWER. For example, when the operator moves the lever to the RAISE position, oil from the control valve enters the ripper diverter valve through the RAISE/TIP OUT passage. Oil then flows into Passage D, goes through the valve body and flows out Port D to the rod end of the ripper raise cylinders. Return oil flows into Port C from the head end of the ripper cylinders, goes through the valve, flows out Passage C and returns to the ripper control valve through the LOWER/TIP IN passage.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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ELECTRICAL SYSTEM



5-1



BAB 5 ELECTRICAL SYSTEM



STARTING AND CHARGING SYSTEMS This schematic shows the components of the D8R starting and charging system. The basic starting system consists of the four batteries, the disconnect switch, the key start switch, the starter relay, and the main relay. With the disconnect switch closed, the negative potential of the batteries is connected to ground (frame). When the operator moves the key start switch to START, power is sent through the key start switch from the 105 RED wire to the 307 ORANGE and 308 YELLOW wires to energize the starter relay and main relay respectively. With the starter relay energized, power is sent to the starter motor through the 304 WHITE wire. After the engine has started, the key start switch is moved to ON and the main relay remains energized, which then provides power to five fuses through the 112 PURPLE wire. PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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After the engine is started and running, the alternator will charge the batteries by directing power through the 109 RED wire, the alternator breaker, and the bus bar to the batteries. The bus bar is used as a junction block for the starter motor, the alternator, and the batteries.



The D8R starting and charging system uses four 3000 CCA 12-Volt maintenance free batteries (1) to provide the electrical power to the starter (2). A 50 amp alternator (3) is used to maintain the charge level of the batteries. An optional 75 amp alternator is available for additional accessories and when more than eight lights are required.



The disconnect switch (4) is used to open and close the ground connection between the negative terminal of the batteries and the machine frame. The switch is convieniently located to the left of the operator's station.



Next to the disconnect switch is the 24-Volt power outlet receptacle (5) that can be used to power service tools. Use the 4C9031 Battery to Tool Cable that has the standard cigarette lighter plug with an integral 1 amp fuse on one end and a standard MS 2-pin connector on the other.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



ELECTRICAL SYSTEM



5-3



If the machine needs to be jump started, an auxiliary start receptacle (1) is standard equipment and is located on the left side of the engine. Two Plug Assemblies are available: the 8S2632 Plug Assembly is 2.45 m (10 ft.) long and the 9S3664 Plug Assembly is 3.81 m (15 ft.) long. If the plug assemblies are not available, refer to the procedure in the Operation Section of the Operation and Maintenance Manual for the D8R Track-type Tractor.



A bus bar (2), located just below the operator's station on the left inside of the frame, is used as a junction to connect the positive power cable from the batteries to the starter. The auxiliary start receptacle and the pre-lubrication timer/solenoid are connected to the bus bar. Located on the left side of the operator's station just above the battery compartment is the fuse panel (3). The fuse panel contains fuses for the following circuits:



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



ELECTRICAL SYSTEM



5-4



- Side and rear flood lamps and radio (15 amp) - Operator monitor (10 amp) - Gauges and service meter (10 amp) - Wiper motor (15 amp) - Cigar lighter (15 amp) - Horn (10 amp) - Back-up alarm (10 amp) - Front dash dome (10 amp) - Key start switch (10 amp) - Blower motor (20 amp circuit breaker) - Alternator (60 amp circuit breaker) In the center of the panel is the diagnostic connector (4).



The



diagnostic connector can be used with the 6V2150 Starting/Charging Analyzer Group to analyze starting and charging problems. Use the Service Manual module "Systems Operation, Testing and Adjusting Starting and Charging Systems for Machines Equipped with Diagnostic Connector" (Form SENR2947) when diagnosing problems in these systems. The main relay (5) is located just below the fuse panel. When the key start switch is moved to the ON position, the main relay is energized. Behind the fuse panel is the starter relay. When the key start switch is moved to START, the starter relay is activated and permits the starter to engage.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



ELECTRICAL SYSTEM



5-5



The key start switch (1) is located on the dash. If the dual twist tiller is in either FORWARD or REVERSE, the engine will not start because a neutral-start switch is installed in the dual twist tiller housing (3). The back-up alarm switch is also contained within the tiller housing. The ether starting aid group (4) is standard equipment. The group is located on the left side of the engine in front of the fuel injection pump. The operator can activate the system by depressing the start aid switch (2) on the dash. A coolant temperature switch (5) is located on the top right rear of the engine head. This system is not functional above 38°C (100°F). For the correct operating procedure, refer to the Operation Section of the D8R Track-type Tractor Operation and Maintenance Manual.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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ELECTRICAL SYSTEM



5-6



ELECTRONIC MONITORING SYSTEM The Electronic Monitoring System (EMS) is designed to alert the operator of an immediate or impending problem in one or more of the machine systems. The system includes the following components: EMS Panel (1): contains eight fault lights, one for each machine system. Master Fault Light (2): flashes to indicate a Category 2 or 3 fault. Panel Test Switch (3): used to test the panel lights, the master fault light, and the fault alarm (not shown because it is located in the compartment with the pilot valve for the dual twist tiller). With the battery disconnect switch ON and the key start switch ON, holding the test switch in the UP position will allow all the panel lights and master fault light to flash. With the engine running, moving the test switch to the UP position will allow all the lights to flash and the fault alarm to sound. If any of the lights or alarm do not function, perform the necessary repairs before starting the engine again.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



ELECTRICAL SYSTEM



5-7



The EMS panel has three warning categories: Category 1:For the first level of warning, only an LED indicator flashes. This alert informs the operator that a system requires attention, but a failure in the system will not endanger the operator or seriously damage any machine components. - Alternator Category 2:For the second level of warning, both an LED indicator flashes and the master fault light flashes on and off. Second level warnings are caused by overheating and requires operator response. They inform the operator to change his method of operation to prevent high temperature damage to one or more systems. - Coolant Temperature - Power Train Oil Temperature - Hydraulic Oil Temperature Category 3: For the third level of warning, an LED indicator will flash, the master fault light will flash, and the fault alarm will sound. This alert requires the operator to immediately shut down the machine as safely and quickly as possible until the problem is corrected. -



Engine Oil Pressure Power Train Oil Filter Coolant Flow Hydraulic Oil Filter



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



ELECTRICAL SYSTEM



5-8



Category 1 Components: The alternator (1) is located on the right front of the engine. The "R" terminal (2) on the alternator provides an AC signal to the EMS control. The EMS control measures the frequency (Hz) of the AC signal and determines the speed at which the alternator is rotating. If the frequency measured is below 94 Hz ± 10%, the alternator alert indicator will FLASH. Category 2 Components: The 7N9785 Coolant Temperature Switch (3) is located at the left rear of the engine head. The switch opens at 107.2°C (225°F).



The 3T8525 Power Train Oil Tmperature Switch (4) is located on the torque converter outlet relief valve. The switch opens at 129.4°C (265°F) and closes at 118.3°C (245°F).



The 8N2248 Hydraulic Oil Temperature Switch (5) is located on the left side of the hydraulic tank. The switch opens at 101.7°C (215°F) and closes at 93.3°C (200°F).



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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ELECTRICAL SYSTEM



5-9



Category 3 Components: The 6T4949 Engine Oil Pressure Switch (1) is located at the right rear of the engine block. The switch opens at 93 kPa (13.5 psi) and closes at 69 kPa (10 psi). The 9X7781 Power Train Oil Filter Switch (4) is located at the front of the power train oil filter (2). The switch is normally open before installation. If the filter element becomes full of debris, the restriction will cause the pressure to increase inside the filter. If the pressure differential increases to 175 kPa (25 psi), the bypass valve will move and the power train oil filter switch will open causing the Category 3 Warning. Located on the rear of the filter is the 9G3341 Power Train Oil Filter Temperature Switch (5). The switch is normally closed below 52°C (125°F), which disables the Category 3 Warning. After the system is warm and if the filter is plugged, the fault will alert the operator.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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ELECTRICAL SYSTEM



5-10



The 9X7781 Hydraulic Oil Filter Switch (6) is located at the rear of the hydraulic oil filter (3). The switch is normally open before installation. If the filter element becomes full of debris, the restriction will cause the pressure to increase inside the filter. If the pressure differential increases to 175 kPa (25 psi), the bypass valve will move and the power train oil filter switch will open causing the Category 3 Warning. Located on the front of the filter is the 8C3569 Hydraulic Oil Filter Temperature Switch (7). The switch is normally closed below 52°C (125°F), which disables the Category 3 Warning. After the system is warm and if the filter is plugged, the fault will alert the operator. The 3E2030 Coolant Flow Switch (8) is located at the right front side of the engine. The switch is normally open and, when the engine is running, coolant flow from the water pump moves the switch paddle closing the switch. If a loss of coolant flow causes the switch to open, the fault will alert the operator.



The EMS Category 3 alarm is activated by the 9W3187 Fuel Pressure Switch (arrow) located on the filter housing. During normal operation (engine running), the fuel pressure switch is open. When the engine is stopped, the fuel pressure switch closes the alarm inhibit input to ground. With this input grounded, the alarm will NOT SOUND.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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ELECTRICAL SYSTEM



5-11



On the dash are four gauges for the operator to monitor the following systems: Hydraulic Oil Temperature (1): Monitors the temperature of the hydraulic oil system (implement and steering). Normal operating temperature is between 75°C and 96°C (167°F and 205°F). If the gauge indicator reaches 102°C (215°F), the temperature in the hydraulic system is too high. Move the cylinders without a load to reduce the temperature.



Fuel Level (2): Monitors the amount of fuel in the tank.



Power Train Oil Temperature (3): Monitors the temperature of the power train oil system. Normal operating temperature is between 82°C and 113°C (180°F and 235°F). If the gauge indicator reaches 129°C (265°F), the temperature in the power train oil system is too high. Move the tiller to NEUTRAL and maintain the engine rpm at HIGH IDLE to reduce the temperature.



Engine Coolant Temperature (4): Monitors the temperature of the engine. Normal operating temperature is between 75°C and 93°C (167°F and 200°F). If the gauge indicator reaches 107°C (225°F) with the cooling system pressurized, the temperature is too high.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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ELECTRICAL SYSTEM



5-12



The 8N2248 Hydraulic Oil Temperature Sender (1) is located on the left side of the hydraulic tank. The 118-0690 Fuel Level Sender (2) is located in the top center of the fuel tank and, if an electrical problem occurs, a mechanical needle on the top of the sender shows the fuel level. The 8N3844 Power Train Oil Temperature Sender (3) is located on the torque converter outlet relief valve. The 6N5926 Engine Coolant Temperature Sender (4) is located on the top front of the engine cylinder head.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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ELECTRICAL SYSTEM



5-13



The optional air conditioning system on the D8R contains the following components:



Evaporator: Low pressure liquid refrigerant boils and collects heat from the surrounding area. Compressor: Increases the pressure and temperature of the refrigerant vapor. Condenser: Removes heat from the high pressure/high temperature refrigerant vapor causing the vapor to change into high pressure liquid refrigerant. Orifice tube/dryer:Regulates the flow of refrigerant to the evaporator coil and the dryer section contains the desiccant for moisture removal. Accumulator: Functions as a liquid/vapor separator and ensures that only vapor will reach the compressor. The optional air conditioning system in the D8R uses the Orifice Tube System. Instead of a thermostatic expansion valve used in earlier systems, an orifice tube is used. The orifice tube is installed in the dryer in the evaporator coil inlet line. The orifice tube has a fixed diameter and does not have the regulating capability of the expansion valve. Therefore, some refrigerant will leave the evaporator in the liquid form. The liquid refrigerant leaving the PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



ELECTRICAL SYSTEM



5-14



evaporator can damage the compressor. Therefore, an accumulator is located in the suction line after the evaporator. The accumulator acts as a liquid/vapor separator and ensures that only vapor will reach the compressor. In this system, the orifice tube is inserted into one end of the dryer. The orifice tube/dryer combination is commonly called the "in line dryer." The accumulator on the in line dryer system does not contain desiccant. The color codes for refrigerant used throughout this section are: Red



- High pressure liquid



Red and White Stripes



- Low pressure liquid



Purple



- High pressure gas



Purple and White Stripes



- Low pressure gas



Green



- Refrigerant oil



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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ELECTRICAL SYSTEM



5-15



The orifice tube/dryer (1) is located on the left side of the engine just below the air cleaner housing. This group contains the orifice tube and the desiccant which dries the liquid refrigerant. Located on the left side of the orifice tube/dryer is the moisture indicator (2). The moisture indicator should be checked at the end of each shift. To check the moisture indicator, look at the color through the sight glass. If the color is blue, the system is dry. If the color is pink, the system has moisture. The moisture must be removed and the orifice tube/dryer must be changed.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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ELECTRICAL SYSTEM



5-16



The orifice tube contains a small tube which extends through the center of a plastic body. The two screens (one on each end) filter the refrigerant that flows through the small tube. The two o-rings are positioned to seal against leakage past the outside of the orifice tube. The two tabs engage the tooling when installing and removing the orifice tube.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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ELECTRICAL SYSTEM



5-17



The compressor (1) is located at the left front of the engine. The refrigerant switch (2) is mounted on the compressor. The refrigerant switch is the low pressure sensing switch that is used to protect the system from damage due to the lack of oil. Located in the electrical circuit to the magnetic clutch, the switch opens and shuts off the compressor when the system pressure decreases below 175 kPa (25 psi). The arc suppressor (3) is used to suppress the high voltage that is created each time the magnetic clutch on the compressor is engaged and released.



The clutch is driven by the engine crankshaft through a belt to the pulley assembly on the magnetic clutch. The pulley assembly turns on the bearing and is not connected to the shaft. The drive plate is splined through the hub to the shaft. The coil assembly is mounted on the frame of the compressor and does not rotate. The electrical current from the thermostat creates a magnetic field in the coil assembly. The magnetic field pulls the drive plate against the pulley assembly. The pulley assembly then turns the drive plate, hub and shaft to operate the compressor. PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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ELECTRICAL SYSTEM



5-18



The accumulator (1) is located just above and to the left of the compressor. The condenser coil (2) is located in front of the hydraulic system oil cooler (3) and behind the radiator.



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ELECTRICAL SYSTEM



5-19



The accumulator contains a diverter cap to keep the liquid away from the vapor line and an oil bleed line to allow oil to flow back to the compressor.



The heating and air conditioning controls are located on the bottom left of the dash. The heating and air conditioning fan speed switch (1) has seven positions. Heating Positions: Off (2), Low (3), High (4), and Defrosting (5) Air Conditioning Positions: Low (6), High (7), and Defogging (8)



The heater temperature control (9) can be rotated from OFF (left) to MAXIMUM (right) heat. The air conditioning temperature control (10) can be rotated from OFF (left) to MAXIMUM (right) cooling.



NOTE: The heating system will be explained later in this presentation.



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ELECTRICAL SYSTEM



5-20



The evaporator coil (1) is located in front of the operator's station. The capillary tube (2) for the thermostatic switch is inserted into the evaporator coil. Moisture that drips off the evaporator coil is collected in a pan. This pan has a vinyl drip tube (3) that directs the water below the machine.



On top of the evaporator coil is the filter (4) that must be cleaned every 10 service hours or daily.



Inside the cab is a filter element (5) that must be cleaned every 10 service hours or daily.



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ELECTRICAL SYSTEM



5-21



The thermostatic switch in the compressor electrical circuit cycles the compressor, allowing the operator to adjust the amount of coolness desired and prevent the evaporator from freezing. The thermostatic switch consists of a pivoting frame attached to a capillary bellows assembly. The capillary tube is filled with refrigerant. The capillary tube is inserted between the evaporator core fins. The gas in the capillary tube expands or contracts, depending on the temperature of the evaporator. The expanding and contracting gas in the capillary tube causes the bellows to expand and contract. The expanding and contracting bellows cause the frame to pivot. Half of the evaporator clutch coil contact is connected to the pivoting frame, and the other half is attached to the body of the switch. The contacts must come together to operate the compressor clutch. The operator regulates the evaporator cooling by varying the space between the contacts. Moving the contacts farther apart (decreasing cooling) causes the bellows to expand farther before closing the contacts. Moving the contacts closer together (increasing cooling) causes the contacts to close with less bellows movement. Adjustable thermostats have provisions for regulating the range between the opening and closing of the contacts. An adjustment screw is located below a removable cover. If an adjusment screw is not found in this location, the thermostat is non-adjustable.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



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ELECTRICAL SYSTEM



5-22



The D8R air conditioning electrical system is very basic. Power for the air conditioner clutch comes from the refrigerant switch which is connected to terminal 2 on the blower motor switch. The thermostat switch is the control for the clutch. To increase or decrease the operator's station temperature, the operator rotates the thermostat switch on the dash to change the compressor cycling. The arc suppressor is used to suppress the high voltage that is created each time the magnetic clutch is engaged or released.



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ELECTRICAL SYSTEM



5-23



To check the air conditioning system, start and operate the engine at HIGH IDLE. Set the air conditioner control for maximum cooling and the fan control on HIGH. Allow two minutes for the system to stabilize. Feel the suction line (1) and the discharge line (2). If the system contains refrigerant, the discharge line will be warmer than the suction line. If the system does not contain or is very low on refrigerant, poor cooling output will result.



Before faulting the refrigerant, check the condition and tightness of the compressor belt. The belt should deflect 14 to 20 mm (.56 to .81 in.) under a 110 N (25 lb.) force.



If the belt tension is acceptable and the system still does not cool, the air conditioner system must be serviced.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



ELECTRICAL SYSTEM



5-24



OPERATOR'S STATION HEATING SYSTEM The optional heating system on the D8R contains the following components:



Heater core: Source of heat to the operator from the engine coolant. Gate valves:Two valves, supply and return, that are used to control the flow of coolant to the heater core. Blower motors and fans: Provide forced air for both heating and cooling. Fan speed control: Seven position switch that controls the blowermotors for heating and air conditioning. The switch uses a largeresistor to provide the LOW speed. HIGH speed does not use theresistor. Heater temperature control:Controls the amount of coolant flow through the heater core.



PT MADHANI TALATAH NUSANTARA MECHANICAL TRAINING SECTION



D8R



ELECTRICAL SYSTEM



5-25



The heating controls are located on the bottom left corner of the dash. The heating fan speed switch (1) has seven positions. Heating Positions:



Off (2), Low (3), High (4), and Defrosting (5)



The heater temperature control (6) can be rotated from OFF (left) to MAXIMUM (right) heat.



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ELECTRICAL SYSTEM



5-26



The blower motors (1) have two speeds through the use of a power resistor (2). When the fan speed switch is moved to the LOW SPEED position, the resistor is connected in series and lowers the voltage to the motors, which decreases the speed of the motors.



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ELECTRICAL SYSTEM



5-27



The D8R heating electrical system is also very basic. Power for the two dual blower motors comes from the blower motor breaker, which is connected to the main relay. The blower motor switch can be wired for both heating and air conditioning. By using the resistor, two speeds are available: LOW and HIGH.



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ELECTRICAL SYSTEM



5-28



The heater control valve (arrow) is located in the return line of the heater core.



When the heater control knob (arrow) is rotated, the torsion cable, which connects the knob to the heater control valve, varies the amount of coolant that flows through the heater core.



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ELECTRICAL SYSTEM



5-29



The heater core shutoff valves are used when the ambient temperature is high enough that the operator does not need any cab heating. The upper valve (1) is the supply gate valve and the lower valve (2) is the return gate valve.



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ELECTRICAL SYSTEM



5-30



CONCLUSION This presentation has discussed the major changes between the D8R and the D8N Track-type Tractors. All the systems of the machine were discussed and included the component locations and functions. For service repairs, adjustments, and maintenance, always refer to the Operation and Maintenance Manual, Service Manuals, and other related service publications. SLIDE LIST.



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6-1



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6-2



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6-3



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6-4



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6-5



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6-6



D8R



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6-7



D8R



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6-8



D8R



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6-9



D8R



LATIHAN SOAL



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6-10



D8R



LATIHAN SOAL



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6-11



D8R



LATIHAN SOAL



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6-12



D8R



LATIHAN SOAL



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6-13



D8R



LATIHAN SOAL



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6-14



D8R



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6-15



D8R



LATIHAN SOAL



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6-16



D8R



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6-17



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6-18



D8R



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6-19



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6-20



D8R



LATIHAN SOAL



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6-21



D8R



LATIHAN SOAL



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6-22



D8R



LATIHAN SOAL



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6-23



D8R



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6-24



D8R



LATIHAN SOAL



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6-25



D8R