Case IH PUMA 130 - Page 56

HYDRAULIC,PNEUMATIC,ELECTRICAL,ELECTRONICSYSTEMS-PRIMARYHYDRAULICPOWERSYSTEM
BAIL10CVT056AAB28
Operationoftheclosedcentrehighpressurehydrauliccircuitisasfollows:-
Thecomponentsinthehighpressurehydrauliccircuitareconnectedbytheirloadsensinglinestothehydraulicload
sensingvalvewhichcontrolstheoutputofthehydraulicpump.
Whenthetrailerbrakes,remotecontrolvalves,hydraulicliftorfrontaxlesuspension(wheretted)areoperating,the
loadsensingvalveonvariableowpistonpump,comparesthepressureinthecomponentloadsenselinewiththe
outputpressureofthehydraulicpump.
Ifpumpoutputpressureislessthanthecombinedpressureoftheloadsenselineandspringforceoftheowcon-
trolvalve,thenpumpoutputcontinuestoincrease.Whencircuitdemandissatisedpumppressureovercomesthe
combinedpressureoftheloadsenselineandowcompensatingvalvespring.Thismovesthespoolintheowcom-
pensatingvalvetotheright,allowingcontrolpressureoiltobedirectedtothevariableowswashplateservopiston,
whichde-strokesthepumptoadjustoutputtocircuitdemand.
HighPressureoilisfedtoasubplateatthebottomoftheremotevalvestackwhereitisdirectedtotheTrailerBrake
valvewhichhaspriorityforsafetyreasons.TheoilisthenredirectedtotheElectronicDraftControlValveandthe
Electro-HydraulicRemoteValves.Withinthesubplateisapressurecompensatingvalvewhichdivertstheoiltothe
lowpressuresystematapressureof18bar(261.00psi).
HighPressureoilisalsofedtothetopoftheRemoteValvestackthroughanendplatewhichincorporatesapressure
limitingvalveandthissuppliesoilat20-22bartothepilotlinegalleriesintheElectro-HydraulicRemoteValves.
Surplusoilfromthechargepumptothevariabledisplacementpumpisfedpastthe0.8barvalveandbooststhe
pressureinthelubricationcircuit.
Thetrailerbrakevalve(1)isunderthecabandismountedonthepriorityvalveatthetopofthemainpumpunit.The
trailerbrakevalveallowspressureoiltoowtothetrailerbrakesystem,whenbothofthetractor'sbrakepedalsare
depressed.
Thetrailerbrakehasabsolutepriorityoverotherservicesinthecircuit.
BAIL10CVT062AAB29
Theremotevalvesareavailableastwo,threeorfourvalvespertractor.
Thevalvescanbedouble-actingwithoatandkickout.
84479138A06/06/2011
A.10.A/28