7.
SWING PRIORITY SYSTEM ARM CYLINDER BUCKET CYLINDER BOOM CYLINDER TRAVEL MOTOR P5 P4 Pi2 Rs MU Pi1 Pn1 Pn2 SH AU PG DR R/G MB MA MU PBa (CW)VB VA(CCW) PAb1 P02 P04 PDb2 RCV PEDAL P T TRAVEL P1 P2 Pu (4) (1) (2) (3) SWING ARM BUCKET BOOM P T PAtr PBtr P T Dr#, dr# A2 PUMP A1 PUMP PILOT PUMP (4) (1) (2) (3) (4) (1) (2) (3) P03 (MCV) A5 P (T/Joint) Pu (MCV) A1 A2 A3 a b d e f g h j A H G F E D B J Psv(Pump) P3 P2 PG(S/Motor) P4 P01(MCV) HYDRAULIC TANK PCsp PAk PDs PCs PCa h2 PS d1 c e2 PS PAb1 PBb1 h1 PS T P1 P(2-EPPR valve) PS PS PS PDa PBk LINE FILTER 330S3HC08 When carrying out the combined operation of swing and arm of the left control valve, the swing speed can be lowered than operating speed of arm.
PCsp pressure from the swing shuttle block change the swing priority spool and decreases the oil flow rate to the next section to make the swing operation most preferential. This is called the swing priority system. For details, refer to page 2-51. 3-13 BC1 N RV2 Cck DR9 Co P05 Do PCo PDo OPTION Ca BC2 NRV1 Cco CoR DoR AkR LCk1 LCk2 LCo CaR BUCKET BbkR PBa PCa PDa PAa2 P P Da DR7 CRa PaL ARM1 DaR LCa BbkR LCa2 ARM2 PAa2 DR6 P02 Csp Db2 BOOM2 Ccb SWING P/R LCar LCbk BbR ARM REGEN Cs Ds PCs PDs DR5 SWING LCs AbR LCb CRb BOOM1 P03 DR3 Ctl Dtl PCtl PDtl Patt (RIGHT) TRAVEL DR1 BtR AtR (RIGHT) TRAVEL (LEFT) TRAVEL MRV