ssp331_gb2

17HowitworksWhenthehydraulicfluidispumpedintothepressureaccumulatorviathenon-returnvalve,pressureinthesystemrisesinrelationtothevolumeoffluidpumped.Thenitrogengasiscompressedandthevolumeofthegaschamberdiminishes.Thefluidvolumerisesatthesamerateuntilthecut-offpressureisreached.Pressureintheaccumulatorismaintainedbythenon-returnvalveandissuppliedtotheanti-rollbarsviaaduct.NitrogengasDiaphragmHydraulicfluidS331_116Toprotectthepressureaccumulator,pressureinthesystemmustbeover70barduringthecouplingoperation.Hydraulicunitpressuresensorforanti-rollbaruncouplingPressureaccumulatorNon-returnvalveAnti-rollbaruncouplingmotorElectricmotorS331_15618DesignandfunctionHydraulicunitpressuresensorforanti-rollbaruncouplingG486Thehydraulicunitpressuresensorforanti-rollbaruncouplingmonitorssystempressureoverarangeof0barto250bar.S331_056S331_050DesignThesensorconsistsofthesensorelectronics(b)andapiezoelectronicelement(a)whichreactstothehydraulicfluidpressure.S331_104baThepressureaccumulatorisrechargedifthepressuredropsbelowaminimumof90barwhentheanti-rollbarsareuncoupled,orwhentheanti-rollbarsarecoupledandthegearboxisswitchedtolow.19HowitworksThehydraulicfluidpressingonthepiezoelectricelementchangesthechargedistributionintheelement.Withouttheactionofpressure,thechargeshaveanevendistribution(1).Ifpressurestartstoact,thechargeschangetheirphysicalposition(2).Thisgeneratesanelectricalvoltage.Thehigherthepressure,themorethechargesareseparated.Thevoltagerises.Itisamplifiedbytheelectroniccircuitsandsentasasignaltotheanti-rollbarcontrolunit.Thevoltageintensityisthereforedirectlyproportionaltothehydraulicpressure.S331_106S331_1082120DesignandfunctionAnti-rollbaruncouplingmotorV326S331_012S331_058CouplingpieceflangeTheanti-rollbaruncouplingmotorisdrivenbytheelectricmotorviathecouplingpiece.S331_102OilflowinthepumpCouplingpieceCouplingpieceflangeTopressureaccumulatorGearwheelsIntakeductfromexpansiontankItdrawshydraulicfluidoutoftheexpansiontankandpumpsittothepressureaccumulatorviaanon-returnvalve.21S331_080HowitworksTheanti-rollbaruncouplingmotorisagearpump.Theopposingrotarymotionofthetwogearwheelspumpsthehydraulicfluidalongtheoutsideofthehousingwall.Adefinitevolumeofhydraulicfluidistakenindependingonthevolumetricspacebetweentheteethandthehousingwall.Thisvolumeisthenpumpedinthedirectionofrotationofthegearwheel.Thetwogearwheelsintermeshinthemiddle.Thevolumetricspacebecomessmallerandthehydraulicfluidispressedoutofthevolumetricspace.Pressurethenrisesinthepressurechamber.Whenthepressurehasrisensufficiently,thenon-returnvalveopensandthehydraulicfluidispumpedtothepressureaccumulator.TopressureaccumulatorGearwheelsIntakeductfromexpansiontankHousingwallVolumetricspacePressurechamberS331_120S331_11822DesignandfunctionExpansiontankS331_056S331_016Theexpansiontankisinsertedontothesupplyunitandsecuredbyahoseclamp.Itisdesignedtopreventthepumpfromrunningdryinanydrivingsituation.Therearetwoconnectionsontopoftheexpansiontank:oneisfortheventlineandtheotherisforthesupplyline.ConnectionforventlineConnectionforsupplylineConnectiontosupplyunitThereisnomin./max.marking.Oillevelischeckedthroughthesupplylineusingamodifiedcustomarycommercialplasticbottle(refertotheServicesectiononpage33).23ElectricmotorTheelectricmotorisadirect-currentmotorwithapermanentmagnet.Itisalsotermedapermanentlyexcitedcollectormotor.S331_056S331_046Duetoitslinearcharacteristiccurves,itisanadaptableandreadilycontrollabledrive.Anti-rollbarcontrolunitJ742Thefittinglocationforthecontrolunitisintheluggagecompartmentunderthesparewheelcover.Itisinsertedonendinamouldedfoampackingwiththeconnectoroutputpointingupwards.Theanti-rollbarcontrolunitisconnectedtothevehicle'sdrivetrainCANdatabus.Itevaluatesthefollowingsignals:●systempressure●switchingstateoftheanti-rollbar●anti-rollbaruncouplingbuttonsignalS331_010Itreceivesthefollowingsignals:●roadspeed●lateralacceleration●gearboxmode(highorlow)Thecontrolunitsendsasignaltotheactuatorsdependingontheresultofevaluation.24DesignandfunctionAnti-rollbarThekeycomponentofthevariableanti-rollbaristhehydraulicallyoperatedactuator.Itispositionedinthemiddleoftheanti-rollbar.Frontaxleanti-rollbarActuatorAnti-rollbararmAnti-rollbararmTheactuatorcontainsaclawcouplingwhichcouplesanduncouplestheanti-rollbararms.S331_082Rearaxleanti-rollbarActuatorAnti-rollbararmAnti-rollbararmS331_08425Thehydraulicallyoperatedclawcouplingconsistsofinput-sideandoutput-sidecouplingelements,aswitchingelement,afail-safespringandananti-rollbaruncouplingsensorpositionedonthehousing.OpencouplingInput-sidecouplingelementOutput-sidecouplingelementSwitchingelementAxialneedlebearingAnti-rollbaruncouplingsensorClosedcouplingS331_088S331_086Twistangleapprox.34°Leftanti-rollbararmRightanti-rollbararmClawcouplingMagneticpininswitchingelementFail-safespringPressurechamber2Pressurechamber1Pressurechamber2Pressurechamber126DesignandfunctionTheswitchingelementisfreetomovealongitsaxis.Itsaxialpositionisdependentonthepressureappliedandinitsclosedposition,theinput-sideandoutput-sidecouplingelementsarefullyinter