Overview of Suspension System Design悬架系统开发

悬架系统开发1OverviewofSuspensionSystemDesign2PurposesofSuspensionSystemsNoiseIsolation:20HzRide:Vertical,PitchandRoll20HzIsolatethebumps,harshnessandnoiseoftheroad;Maintainbodybounce,pitchandrollwithinacceptablelimits.Handling:responseofthevehicletodriverinput.Todesignvehiclesthathandlewell,theengineermustdesignsuspensionsthatAllowwheelstomaintaintheproperorientationrelativetotheroadsurfaceReacttotheforcesproducedbythetiresduringacceleration,brakingandcornering悬架系统开发SuspensionSystemDesign3OverallSuspensionDesignProcessDefinitionofSuspensionCharacteristicsFront/RearSuspensionTypeSelectionSuspensionSystemSynthesisForComponentTargetsSuspensionLayoutDesignSuspensionComponentDesignSuspensionPerformanceAnalysisandEvaluationMeetPackaging,Cost,WeightandObjectiveBuildFullVehicleModel,AnalysisandEvaluationNoYesMeetComponentWeight,CostandObjectiveYesNoNoMeetVehicleSystemObjectiveBuildNext-LevelVehicleCheckWithOtherSubsystemandModifyDesignYesSuspensionSystemDesign4AssemblyofChassisSubsystemSuspensionSystemDesign5CommonSuspensionTypesSuspensionSystemDesign6SuspensionDesignGuidelinesSelectsuspensiontypeforrightgeometrytotunerideandhandlingrelativelyindependently.(1.multi-linkSLA,2.DoubleA-armSLA,3.Strut,4.SolidAxle)Toeisolatenoise(1.Usesoftbushing,2.Usespringisolator,3.Useurethanematerialforisolatornotrubber,4.Achievejointstiffnessratiogreaterthan5)Toachieveagoodride,designforalowrecessionrateTomaximizehandlingpotential,designforahighlateralrateTominimizethefrictionwithlow-frictionmaterialsandthesuspensiondesignthatreducestheeffectsofloadsTocontrolcompliancesteerbystrategicplacementofpivotpointsandwithspecificofcombinationsofbushingstiffnessSuspensionSystemDesign7SuspensionSelectionCriteriaRideHandingNVHPackagingReliabilityAssemblyeaseAdjustmentcapacityPiececostInvestmentWeightServiceabilityBalanceandWeighting,DOESuspensionSystemDesign8Non-IndependentSuspensionsLowCostBetterGroundClearanceforOff-RoadVehicleDifficulttooptimizehandlingandrideToeandcamberarenotdirectlyaffectedbyloadsBeamaxleshavetheultimateincamberpatterninthatthetireisalwaysperpendiculartothesmoothroadandhasminimaltire-wearproblemsBeamaxleforpassengercarsRigidaxleforSUVandtrucksSuspensionSystemDesign9IndependentSuspensionsHighCostFlexibilityofDesignRelativelyeasytooptimizehandlingandrideToeandcamberaredirectlyaffectedbyloadsSuspensionSystemDesign10ExamplesofIndependentSuspensionsSLAMulti-linkSuspensionSystemDesign11ExamplesofIndependentSuspensionsStrutSuspensionSystemDesign12AssemblyofFrontSuspensionSubsystemSuspensionSystemDesign13AssemblyofRearSuspensionSubsystemSuspensionSystemDesign14ExamplesofSolidandBeamAxlesSolidBeamSuspensionSystemDesign15ExamplesofSolidandBeamAxlesTwistAxleSolidAxlewithPanhardRodSuspensionSystemDesign16ExamplesofSolidandBeamAxles5-LinkSolidAxleSuspensionSystemDesign17SuspensionSystemComponentsKnuckleorspindleControlarmsSpringsSpringseatisolatorShocksandstrutsJounceBumperStabilizerbarandlinkBushingsandballjointsSuspensionSystemDesign18ControlArm/Knuckle/SpindleSuspensionSystemDesign19SuspensionComponentsSuppliersmayproducethecomponentsofchassissystemSuspensionSystemDesign20PivotsofSuspensionSystemsSuspensionSystemDesign21PivotPointsofSuspensionSystemsSuspensionSystemDesign22OverviewofSuspensionKinematicsSuspensionSystemDesign23HierarchyofParametersToepatternCamberpatternRoll-centerheightRoll-centerheightchangeCastertrailScrubradiusAckermannScuffAnti-dive/Anti-tiffSteering-axisinclinationSuspensionSystemDesign24DevelopmentofParametersParametersHowtoDevelopToepatternControlledbytherelativelengthoftierodsandcontrolarmsandlocationofpivotpointsCamberpatternAffectedbycontrolarmlengthandlocationofpivotpoints.Increasecamberchangewithsmallercontrolarmratioandlessdistancebetweenthem;Designnegativecamberpatternsinboththefrontandrear;Strivefornegativecamberinjounceandpositivecamberinrebound;Suspensionselectionisimportant.TheMacphersonstrutprovidesverylittlecamberchangeandlittlelatitudefordesigninginchange.RollcenterheightCustomerpreferencesvaryinthewayavehiclerollsandundersteersinaturn.Rollstiffness,rollsteer,compliancesteerandroll-centerlocationaffectrollangleandnetsteeringeffect.Rollcenterlocationisaffectedbyraisingorloweringthepivotpoints.SteeringratioThesteeringratioaffectssteeringquickness.Vehicledevelopmentengineerswillspecifytheratio.AckermanStriveforahighpercentAckermanninwhichtheradiiofwheelpathsoriginatefromacommoncenter.ScuffScuffandcamberpatternarerelatedtoeachotherandtotherollcenterheight.Ofthethree,scuffisthelowestpriority.Antidive/Anti-liftRaisingorloweringtheSVICcontrolsthevehiclepitch.Itisaffectedbyraisingorloweringthepivotpoints.ScrubradiusScrubradiusisdeterminedbythefrontviewlocationofthesteeringaxis.Positionthesteeringaxistominimizethescrubradius.SteeringaxisinclinationPositionthelowerballjointandtheupperballjoint(SLA)orupperstrutmount(strut)toachievethespecifiedsteeringaxisinclination.SuspensionSystemDesign25EffectsofParametersCharacteristicsEffectonPerformanceToeangleTirewea