日立辅助002主液压泵

MainHydraulicPump

SMCSCode:5070-MV

Construction

Illustration30

Mainpumps

Proportionalreducingvalve(powershiftpressure)

Casedrainport

Outletport(rightpump)

Outletport(leftpump)

Outletport(pilotpressure)

Port(negativeflowcontrolpressureforrightpump)

Port(powershiftpressureforrightpump)

Port(pilotoiltoproportionalreducingvalve)

Housing

Port(pressuresensor)

Inletport(pilotpump)

Port(pressuresensor)

Rightpump

Inletport(supplyoilfromthehydraulictank)

Leftpump

Port(powershiftpressureforleftpump)

Port(negativeflowcontrolpressureforrightpump)

(71)Pilotpump

Themainpumpsconsistofrightpump(13)andleftpump(15).Therightpumpandtheleftpumparecontainedinanintegralhousing.Bothpumpsarevariabledisplacementpistonpumps.Therightpumpandtheleftpumpareidenticalinconstructionandoperation.

Supplyoilfromthehydraulictankentersinletport(14).Thesingleinletportiscommontobothpumps.Therightpumpdeliversoilthroughoutletport(3).Theleftpumpdeliversoilthroughoutletport(4).Supplyoilforpilotpump(71)entersthroughinletport(11).Thepilot

pumpdeliversoilthroughoutletport(5).

Boththerightpumpandtheleftpumphavearegulatoraspartofthepumpcontrolsystem.Theflowcontrolofthepumpsisperformedbytheoperationoftheregulators.Thecontrolsystemisidenticalforbothpumps.

Proportionalreducingvalve(1)forthepowershiftpressureislocatedintherightpumpregulator.Theproportionalreducingvalveiscontrolledbytheengineandpumpcontroller.Theproportionalreducingvalvecontrolsthepowershiftsignalforboththerightpumpandtheleftpump.

Negativeflowcontrolpressurefromthemaincontrolvalveenterstherightpumpregulatoratport(6).Negativeflowcontrolpressurefromthemaincontrolvalveenterstheleftpumpregulatoratport(17).

Casedrainoilfromthepumphousingflowsfromport(2)tothecasedrainfilter.

Operation

Illustration31

Mainpumps(sectionalview)

(4)Outletport(leftpump)

(9)Housing

(14)Inletport(supplyoilfromthehydraulictank)

(15)Leftpump

Gear

Driveshaft

Swashplate

Driveshaft

Gear

Plate

Retainer

Pistonslipper

Pin

Piston

Barrel

Portplate

Passage

(70)Portblock

(71)Pilotpump

Gear(22)ofdriveshaft(21)mesheswithgear(18)ofdriveshaft(19).Gear(18)andgear(19)havethesamenumberofteeth.Driveshaft

(21)ofrightpump(13)isconnectedtotheenginebyacoupling.Whentheengineisrunning,driveshaft(19)anddriveshaft(21)rotateatthesamespeed.Therefore,rightpump(13)andleftpump(15)rotateatthesamespeed.

Barrel(28)containsninepistons(27).Pistonslippers(25)areconnectedtopistons(27)byretainers(24).Thepistonslippersarepressedagainstplate(23).Plate(23)liesonswashplate(20).Barrel(28)issplinedtodriveshaft(21).Asdriveshaft(21)rotates,thebarrel,thepistonsandthepistonslippersrotatearoundswashplate(20).

Theangleofswashplate(20)determinesthelengthofstrokeofpiston(27).Astheangleoftheswashplateincreases,thelengthofstrokeofthepistonsincreasesandtheoutputflowofthepumpincreases.Aspistonslipper(25)rotatesaroundtheswashplate,thepistonmovesoutofbarrel(28).Thepistondrawsoilfrompassage(30)ofportplate(29)duringthismovement.Asthepistonslippercontinuestorotatearoundthes