Toro Groundsmaster 360 - Page 74

ForwardDirection(continued)
Intheforwarddirection,pilotdirectionalvalvesPD1andPD2inthetraction
manifoldassemblyareshifted.Theseshiftedvalvesalongwiththecheckvalves
(CV1andCV2)helptoprovideuidwhereneededinthetractioncircuitsfor
optimaltractionoperationwhenturning.
The2transmissiontractioncircuitsincludeushingvalves(oneforeachtraction
circuit)inthepistonpumpthatbleedoffasmallamountofhydraulicuidfor
coolingoftheclosedlooptractioncircuits.Theushingvalvesareopenedonly
duringforwarddirectionoperation.Whentheushingvalvesareunseated,some
uidfromthelow-pressuresideofthetractionloopisreturnedtothehydraulic
tank.Theuidlossfromtheclosedloopsthroughtheushingvalvesisreplaced
bythechargepump.
Thetractionmanifoldassemblyincludesabi-directionalreliefvalve(CRV)and
oricettingstopreventpressuredifferencesinthe2circuitsreducingtire
scufngwhenturning.
Toprovide4-wheeldynamicbrakingwhenthetractionpedalisreleased,the
pilotdirectionalvalvesPD1andPD2inthetractionmanifoldassemblyshiftto
theirnormallyclosedposition.Thisdisablesthecheckvalves(CV1andCV2)
ensuring4-wheelhydrostaticbraking.
ReverseDirection
g036058
Figure26
1.PortA4.PortD
2.PortB5.Balancinghose
3.PortC
Thetractioncircuitoperatesessentiallythesameinreverseasitdoesinthe
forwarddirection.
Whenatractionpedalispushedforreverse,thelinkageconnectedtothe
pedalpositionstheswashplatesinbothtransmission-pistonpumpstoprovide
hydraulicuidowfromthetransmission(portBandD).Thisuidowstothe
frontwheelmotorsandthenontotherearwheelmotorsturningthemotorsin
thereversedirection.Theuidowfromtherearwheelmotorsreturntothe
transmission(portAandportC)andiscontinuouslypumpedwhilethetraction
pedalispushedforreverse.
Inthereversedirection,transmissionpumpowisroutedtoafrontwheelmotor
andthentotheoppositerearwheelmotor(e.g.,therightfrontandthentotheleft
rear).Thereversetractioncircuitreliefvalvesettingis27,600kPa(4,000psi).
HydraulicSystem:HydraulicFlowDiagrams
Page4–16
Groundsmaster360
16225SLRevC