Toro Groundsmaster 5910 Series User Manual

TractionCircuitOperation
Avariabledisplacement,bi−directionalpistonpumpisdirectlycoupledtothe
engineywheeltoprovidehydraulicowforthetractioncircuit.Thepistonpump
swashplatemovementiscontrolledbyapumpmountedelectricaldisplacement
control.Pushingthetractionpedalrotatesapotentiometerthatprovidesan
inputtothemachinemasterToroElectronicController(TEC).Thecontrollerin
turnsendsacorrespondingPWM(PulseWidthModulation)outputsignaltothe
pistonpumpdisplacementcontroltorotatethepumpswashplateaccordingly
tocontrolthepump’soutputanddirection.Whenthetractionpedalispushed
intheforwarddirection,solenoidS1onthedisplacementcontrolisenergized.
SolenoidS1istheuppersolenoidonthepumpcontrolassembly.SolenoidS2is
energizedwhenthetractionpedalispushedinthereversedirection.
Thetractioncircuitprovidesoperationineitherlowrangetractionspeed
(mow/fourwheeldrive)orhighrangetractionspeed(transport/twowheeldrive).
Solenoidvalve(SV)inthetractionmanifoldisenergizedbytheslaveTEC
controllerwhenthehighrangetractionspeed(transport)isselected.
Frontandrearwheelmotorsarexeddisplacement,hightorque,lowspeed
radialpistonmotors.Frontmotorsare2−speeddesignandrearmotorsare
singlespeed.Theoilfromthepistonpumpisdirectedtothefrontandrearwheel
motorsthroughthetractionmanifold.
Operatingpressureonthehighpressuresideoftheclosedlooptractioncircuitis
determinedbytheamountofloaddevelopedatthewheelmotors.Astheload
increases,circuitpressurecanincreasetoreliefvalvesettings(350bar(5080
PSI)inbothforwardandreverse).Ifpressureexceedsthereliefsetting,oil
owsthroughtheunseatedreliefvalvetothelowpressuresideoftheclosed
looptractioncircuit.
Note:Thepiston(traction)pumphighpressurereliefvalvesincludethehigh
pressurereliefvalve,achargecircuitcheckvalveandabypassvalvetoallow
themachinetobetowedalimiteddistance.
Tractioncircuitpressure(forwardandreverse)canbemeasuredattestttings
attachedtothesidesofthepistonpump.Theforwardtractionportisontheright
sideofthepumpandthereversetractionportisontheleftside.
TheSmartPower
TM
featurepreventstheenginefromslowingdowninheavyload
conditions(e.g.cuttingtallgrass)byautomaticallydecreasingthetractionspeed
ifnecessary.Withareducedtractionspeed,thecuttingbladescancontinueto
beatoptimumspeed.
Tractionpumpowisdirectedtotherearwheelmotorsandtheoppositefront
wheelmotorstomaximizetraction.Toreducetirescufngwhenturning,traction
systempressureisequalizedinthetractionmanifoldwithanoriceandarelief
valve.Checkvalvesinthetractionmanifoldpreventcircuitcavitationifthefront
wheelmotorsshouldlosetraction.
Tofurtherenhancetractioncontrol,thecuttingdecklift/lowercircuitisequipped
withacounterbalancesystem.Counterbalanceisachievedbyapplyinga
constantpressuretotheliftcylinderstoliftthecuttingdecksslightly.This
actioncausessomeofthecuttingdeckweighttobetransferredtothetraction
unittoimprovetraction.Apre−setcounterbalancevalve(RV3)locatedinthe
steering/deckliftmanifoldcontrolstheamountofcounterbalancepressureinthe
liftcircuit.Thepressuresettingcanbemodiedforsnoworblowerattachments.
Thetractionpumpandwheelmotorsuseasmallamountofhydraulicuidfor
internallubrication.Fluidisdesignedtoleakacrossthepumpandmotorparts
andintothecomponentcasedrain.Thisleakageresultsinthelossofhydraulic
uidfromtheclosedlooptractioncircuitthatmustbereplaced.Thetraction
chargecircuitisdesignedtoreplacethistractioncircuitleakage.
HydraulicSystem:HydraulicFlowDiagrams
Page5–14
Groundsmaster
®
5900&5910
16227SLRevB

Toro Groundsmaster 5910 Series Specifications

General

Brand	Toro
Model	Groundsmaster 5910 Series
Category	Lawn Mower
Language	English