8. TRAVEL FORWARD AND REVERSE OPERATION ARM CYLINDER BUCKET CYLINDER BOOM CYLINDER R/H L/H REG Dr Ps Ps MU MB MA MB VA(FW) VB(BW) Dr P RCV PEDAL PAtr (2) SWING ARM P T (4) (1) (2) (3) A E D B Psv(Pump) P2 a b d e f g h j h2 PS SH d1 e1 c e2 PS h1 PS P(2-EPPR valve) PCsp PAk PDs PCs PCa PS PS PAb1 PBb1 T P1 LINE FILTER PS PDa PBk 330S3HC16 When the travel levers are pushed forward or reverse position, the travel spools in the main control valve are moved to the forward or reverse travel position by the pilot oil pressure from the remote control valve. The oil from the each pump flows into the main control valve and then goes to the each travel motor through the turning joint.
The return oil from both travel motors returns to the hydraulic oil tank through the turning joint and the travel spools in the main control valve. When this happens, the machine moves to the forward or reverse.
3-22 NRV2 Cck Bk Ak P04 PBk PAk BUCKET PCbc BbkR PBa2 PAa2 ARM2 DR6 P02 PBa Abk PBrc ARM REGEN PAbk DR4 BC2 Cco NRV1 CoR DoR AkR LCk1 LCk2 ION LCo CaR BUCKET BbkR DaR M1 LCa BbkR LCa2 ARM2 PAa2 DR6 Ccb OM2 SWING P/R LCar LCbk BbR ARM REGEN P02 Abk PBrc PAbk DR4 Cs AbR Ds PCs PDs DR5 SWING LCs LCb P03 DR3 Ctl BtR Dtl AtR PCtl PDtl SH Patt ( TR RIG AVH ET L) P T TRAVEL PS DR1 P01 PtrPS TS P1 P2 Pu 1) (4) (3) Btr PDtl PCtl Dr#, dr# BUCKET P T BOOM TRAVEL SPEED SOLENOID VALVE P03 P Pu (MCV) (T/Joint)(MCV) (3) (1) (2) (4) F G H J A5 A3 A2 A1 P4 P01(MCV) P3 PG(S/Motor) ING LCs AbR LCb CRb BOOM1 BtR AtR HT) VEL (LEFT) TRAVEL BUCKET P T BOOM TRAVEL SPEED SOLENOID VALVE P03 P Pu (MCV) (T/Joint)(MCV) (3) (1) (2) (4) F G H J A5 A3 A2 A1