液压开心与闭心系统JOHN+DEERE+.ppt

JOHNDEEREOpen&ClosedCenter,BasicHydraulicsCertification,Module4,2,Tank,Tank,PUMP,PUMP,SPOOLVALVES,3,OPENCENTERVALVE,(INNEUTRAL),Hydraulicsystemwithgearpump,4,Reservoir,FixedPump,ControlValve,Cylinder,w,w,ReliefValve,OPENCENTERVALVE,RETRACT,(RETRACT),Hydraulicsystemwithgearpump,5,Directionalcontrolvalve(opencenter),RESERVOIR,RELIEFVALVE,FIXEDDISPL.PUMP,#1,#2,#3,Inneutraltheoilpassesthroughthevalvesinseriesandreturnstothereservoir.,4-Open&ClosedCenterSystems,5,6,Directionalcontrolvalve(opencenter),RESERVOIR,RELIEFVALVE,FIXEDDISPL.PUMP,#1,#2,#3,Whenthevalveisoperated,thereturnisclosed,Onlyonevalvewilloperatewithhighpressureoil,4-Open&ClosedCenterSystems,6,Note:Oildisplacedfromrodendofcylinderisavailabletothe#2valve,0PSI,LowPressureTovalve#2,*,*,*,7,OPENCENTERWITH,SERIES/PARALLEL,CONNECTION,RETURNWHENINNEUTRAL,PARALLELPATH,RESERVOIR,FIXEDDISPL.PUMP,#2,#1,x,Allvalvesinneutral,#3,4-Open&ClosedCenterSystems,7,8,Whenanyvalveisoperated,thereturnisclosedandoilisavailabletoallvalvesthroughtheparallelline.,RETURN,PARALLELPATH,RESERVOIR,FIXEDDISPL.PUMP,#3,x,#2,#1,OPENCENTERWITH,SERIES/PARALLEL,CONNECTION,4-Open&ClosedCenterSystems,8,9,Whentwoormorevalvesareactivatedatonce,thecylinderwiththesmallerloadoperatesfirst,RETURN,PARALLELPATH,RESERVOIR,FIXEDDISPL.PUMP,Whenthevalveisoperated,thereturnisclosed,RETURN,4-Open&ClosedCenterSystems,9,10,CLOSEDCENTERVALVE,(INNEUTRAL),11,CLOSEDCENTERVALVE,(RETRACT),12,CLOSEDCENTERSYSTEM,VariableDisplacementPump,ChargePump,Whentwoormore,valvesareactivated,atonce,thecylinder,withthesmal