10.
COMBINED BOOM UP AND ARM OPERATION ARM CYLINDER BUCKET CYLINDER BOOM CYLINDER TRAVEL MOTOR P5 P4 Pi2 Rs MU Pi1 Pn1 Pn2 SWING MOTOR PBa PAb1 P02 P04 PDb2 A2 PUMP A1 PUMP PILOT PUMP HYDRAULIC TANK 330S3HC26 BC1 NRV2 Cck R9 Co 05 Do Co Do OPTION Ca Holding valve Da BC2 NRV1 Cco CoR AkR LCk1 LCk2 Arm flow limit spool DoR LCo Relief valve CaR DaR BUCKET BbkR R7 CRa aL ARM1 Make up valve LCa LCa2 ARM2 PAa2 DR6 sp b2 BOOM2 Ccb SWING P/R LCar LCbk BbR ARM REGEN P02 Abk PBrc PAbk DR4 P P D Cs Ds Cs Ds R5 SWING LCs AbR LCb CRb BOOM1 P03 DR3 Ctl Dtl PCtl PDtl SH Patt ( TR RIG AVH ET L) PS DR1 P01 PtrPS TS 03 R3 tl tl Ctl Dtl att (RIGHT) TRAVEL R1 BtR AtR (LEFT) TRAVEL MRV When the boom up and arm functions are operated, simultaneously each spool in the main control valve is moved to the functional position by the pilot oil pressure from the remote control valve.
The oil from the A1 pump flows into the boom cylinders and arm cylinder through the boom 2 spool and arm 1 spool in the left control valve. The oil from the A2 pump flows into the boom cylinders and arm cylinder through the boom 1 spool, arm 2 spool and the parallel and confluence oil passage in the right control valve. Also, when the boom up and arm in functions are operated simultaneously, the boom up operation preference function is operated by the pilot pressure P02 and then the flow into arm 2 spool is reduced by shifting of the arm in flow limit spool. Therefore, the most of pressurized oil flows into boom 1 spool than the arm 2 spool to make the boom up operation more preferential.
The boom and arm are operated. 3-33