液壓開心與閉心系統(tǒng)JOHNDEERE

1、JOHN DEEREOpen & Closed Center BasicHydraulics CertificationModule 41OPEN CENTER VALVECLOSED CENTER VALVETankTankPUMPPUMPSPOOL VALVES2OPEN CENTER VALVEReservoirFixedPumpControl ValveCylinderwwReliefValveHOLD(IN NEUTRAL)Hydraulic system with gear pump3ReservoirFixedPumpControl ValveCylinderwwReliefVa

2、lveOPEN CENTER VALVERETRACT(RETRACT)Hydraulic system with gear pump4Directionalcontrol valve(open center)RESERVOIRRELIEF VALVEFIXEDDISPL.PUMP#1#2#3OPEN CENTER WITHSERIES CONNECTIONIn neutral the oil passes through the valves in series and returns to the reservoir.4 - Open & Closed Center Systems55Di

3、rectionalcontrol valve(open center)RESERVOIRRELIEF VALVEFIXEDDISPL.PUMP#1#2#3OPEN CENTER WITHSERIES CONNECTIONWhen the valve is operated, the returnis closedOnly one valve will operate withhigh pressure oil 4 - Open & Closed Center Systems6Note: Oil displaced from rod end of cylinder is available to

4、 the #2 valve0 PSILow Pressure To valve #2*6OPEN CENTER WITHSERIES / PARALLELCONNECTIONRETURN WHEN IN NEUTRALPARALLEL PATHRESERVOIRFIXEDDISPL.PUMP#2#1xAll valves in neutral#34 - Open & Closed Center Systems77When any valve is operated, the returnis closed and oil is available to all valves through t

5、he parallel line. RETURNPARALLEL PATHRESERVOIRFIXEDDISPL.PUMP#3x#2#1OPEN CENTER WITHSERIES / PARALLELCONNECTION4 - Open & Closed Center Systems88When two or more valves are activatedat once, the cylinder with the smaller load operates firstCONNECTIONOPEN CENTER WITHSERIES / PARALLEL RETURNPARALLEL P

6、ATHRESERVOIRFIXEDDISPL.PUMPWhen the valve is operated, the returnis closed RETURN4 - Open & Closed Center Systems99CLOSED CENTER VALVEReservoirControl ValveCylinderHOLDVariableDisplacementPump(IN NEUTRAL)10CLOSED CENTER VALVE(RETRACT)ReservoirControl ValveCylinderRETRACTVariableDisplacementPump11CLOSED CENTER SYSTEMVariable Displacement PumpCharge PumpWhen two or morevalves are activatedat once, the cy