Toro Reelmaster 3100-D - Page 98

LowerCuttingUnits
Thegearpump(P2)isdirectlycoupledtothehydrostatthroughgearpump
(P1).Itsupplieshydraulicpressure(chargepressure)forraisingandlowering
thecuttingunits,operatingthesidewinderunit,andreplenishingtheclosed
looptractioncircuit(chargepressure).Thepumptakesitssuctiondirectlyfrom
thehydraulictank.
Duringconditionsofnotliftingorloweringcuttingunits,owfromthegear
pump(P2)isby−passedthroughthepowersteeringvalve,2−spoolvalve,and
hydraulicmanifolddirectlytothehydrostatandthechargereliefvalve.Flowthen
returnstothehydraulictank.
Circuitoperationforloweringthecuttingunitsissimilartoraisingthem.However,
pressureisrelievedfromtheliftcylinders,andthisactionallowsthemtolower.
Whenthecuttingunitsaretobelowered,the2−spoolvalveispositionedby
movingthecuttingunitshiftlevertoLOWER.Pressurefromgearpump(P2)is
usedtoshiftthepilotvalveinthe2−spoolvalve.Thisshiftingofthepilotvalve
allowshydraulicpressuretorelievefromthecapendoftheliftcylinders.Flow
fromthecapendoftheliftcylinderscausesthecuttingunitstolower.Atthe
sametime,theuidrelievedfromthecapendoftheliftcylindersgoesintothe
rodendofthecylindersandbackthroughthehydraulicmanifoldtothehydrostat.
Whenthecuttingunitshiftleverisreleased,springactionreturnsanddetents
thevalveintotheoatpositionwhileby−passingowbacktothehydrostat.The
pilotvalvethenshiftstoitsoriginalpositionandstopsliftcylindermovement.The
cylinderpositionislockedinplacesincethereisnocompletecircuitofow
toandfromtheliftcylinders.
HydraulicSystem:HydraulicFlowDiagrams
Page5–22
Reelmaster
®
3100-D/3105-D
20252SLRevA