汽车制动NVH

AutomotiveBrakeNVH汽车制动NVHSeongK.RheeSKRConsulting,LLCIntroductiontoBrakeNoise&Vibration25001K10K20KL.F.Squeal低频尖叫声HighFrequencySqueal高频尖叫声Frequency频率(HZ)Groan低沉噪音Moan低沉噪音Roughness粗糙度(5-60Hz)DTVFrequencyRangeforDiscBrakeNoiseandVibration盘式制动器的噪音和振动的频率范围IntroductiontoBrakeNoise&Vibration3SOUND声音Rapidlyfluctuatingairpressurecausedbyvibratingsurface由表面振动引起的空气压力的迅速振荡IntroductiontoBrakeNoise&Vibration4HIGHFREQUENCYSQUEAL高频尖叫声CausedbyVibrationofDisc由制动盘振动引起IntroductiontoBrakeNoise&Vibration5LOWFREQUENCYSQUEAL低频尖叫声CausedbyVibrationofCaliperBody,AnchorBracket,orKnuckle由卡钳,挂钩或者关节的振动引起IntroductiontoBrakeNoise&Vibration6VibrationExcitationOfDisc/CaliperAssembly制动盘/卡钳总成振动的激发zCausedbyPadandBackingPlateVibration/Impactz由刹车片和钢背的振动/冲击引起zPad-DiscModalCouplingz刹车片和刹车盘的结合方式zBackingPlate-CaliperInteractionsz钢背和卡钳的相互作用zContactPressureDistributionz接触压力的分配IntroductiontoBrakeNoise&Vibration7PracticalSquealSolutions;Excitationvs.Response实际尖叫的解决办法;激发和响应zDe-CouplingofDisc,PadandCaliperz判定耦合的因素:制动盘,刹车片和卡钳的zDampedDisc软质制动盘zDampedPad软质刹车片zPadChamfer刹车片倒角zLowerFriction(Humidity)低摩擦系数(湿度)zNoMetalPick-uponPad(Lubricants)刹车片无金属(润滑剂)IntroductiontoBrakeNoise&Vibration8zAnti-NoiseShimandClip消音片和夹子zSmoothSlidingofPadAssembly刹车片总成流畅滑动zFlatnessofBackingPlate钢背的平面zCaliperDesignforUniformContactPressure均匀接触压力的卡钳设计zPartVariabilityReduction(Modals)部分可变性的减少(程式)PracticalSquealSolutions;Excitationvs.Response实际尖叫的解决办法;激发和响应IntroductiontoBrakeNoise&Vibration9BrakeSqueal制动尖叫声zBrakesquealisaphenomenonofdynamicinstabilitythatoccursatoneormoreofthenaturalfrequenciesofthebrakesystem.z制动尖叫声是一种动态不稳定性现象，发生于制动系统的一个或者更多的固有频率上。zTheexcitationcomesfromthefrictioncouple.受摩擦力偶激发。zPadsandrotorcouplinghasmajorimpactonmidtohighfrequency(4~16kHz)squeal.z刹车片和刹车盘接合主要产生中等到高频(4~16kHz)尖叫声。-Thediscrotorisactinglikea“speaker”(soundwaveradiatedfromtherotorsurfaces).-刹车盘类似于一个喇叭（声波从刹车盘表面辐射开去）。zLowfrequency(1~4kHz)squealtypicallyinvolvescaliper,anchorbracket,knuckleandsuspension,inadditiontopadsandrotor.z低频(1~4kHz)尖叫除了来自于刹车片和刹车盘外，主要来自卡钳，挂钩，关节和悬挂。IntroductiontoBrakeNoise&Vibration10FactorsInfluencingLowFrequencyBrakeNoise影响低频制动噪音的因素ThicknessVanepatternHatsectionMaterialRotorBridgeAnchorbracketClipsRailslippersCaliperStiffness/massKnuckleStiffness/massDampingSuspensionMulevel/variationMaterialGeometryInsulatorPadLowfrequencybrakeIntroductiontoBrakeNoise&Vibration11FactorsInfluencingHighFrequencyBrakeNoise影响高频制动噪音的因素ThicknessVanepatternHatsectionMaterialRotorMulevelMaterialGeometryInsulatorCaliperAnchorbracketPadHighfrequencysquealIntroductiontoBrakeNoise&Vibration12VehicleTest整车测试zTheultimatejudgeforsuccessfulnoisesolutions.z成功解决噪音问题的最终判断。zTestprocedures测试程序(NorthAmerica北美):yLosAngelesCityTraffic(LACT)-Standardbrakenoiseandwearvalidationtest;DifferentroutesforeachOEy洛杉矶市交通测试(LACT)–标准制动噪音和磨耗确认测试；对每个原装车辆不同路线的测试yDetroitSuburbanTraffic(DST)-MainlyforDTVy底特律郊区交通测试(DST)–主要用于DTV测试yOthertestsfromdifferentOEMsandsuppliers-Fornoiseinvestigationandquickvalidationy来自主机厂和供应商的其他测试–用于噪音研究和快速确认zDriver’snoiseratings,noisecounts,soundpressureand/oraccelerationdataarecollectedthroughoutthetest.z驾驶员收集了整个测试过程中的噪音出现机率，噪音点，声音强度和/或加速度数据IntroductiontoBrakeNoise&Vibration13DynamometerTest台架测试zProvidesnoisevalidationwithinacontrolledenvironment.z在可以控制的环境下确认噪音。zLowercostandquickertorunthanvehicletest.z和整车测试比，成本低并且时间短。zTestprocedures测试程序:ySAEJ2521-DevelopedafterAKwiththeadditionofinertiastopsySAEJ2521–AK测试基础上增加了增加了惯量制动yAK-Europeanoriginatedprocedure(mainlydragstops)yAK–起源于欧洲的测试程序（主要拖曳制动）ySimulatedLACT-AseriesofstopssimilartoLACTdrivingconditionsy模拟LACT–一系列类似LACT驾驶条件的制动yThecombinationoftheabovey以上几种相结合的测试zSoundpressuredataaretypicallycollectedthroughoutthetest.z测试收集了整个过程有代表性的声音强度数据。IntroductiontoBrakeNoise&Vibration14RepeatabilityandReproducibilityofBrakeNVHTesting制动NVH测试的可重复性和再现性zTheunderliningmechanismsofbrakesquealinvolvemultipleaspectsinthebrakesystem.Itisnotuncommontofacethefollowingproblems:z制动尖叫声关键的机理包括制动系统的方方面面。通常会见到以下问题：yCorrelationbetweenvehicleanddynamometertestsy整车和台架测试的关系yRepeatabilityandreproducibilitybetweenvehiclesordynamometersy整车和台架测试的可重复性和再现性zCorrelationismoredifficulttoachieveforlowfrequencysquealsincemorecomponentscomeintoplay.z低频尖叫声更难完成分析，因为起作用的因素更多。zEnvironmentalfactorssuchasweather,ambienttemperature,humidityandroaddustmayalsoinfluencetestresults.z环境因素，例如：天气，周围的温度，湿度和陆上灰尘都可能影响测试结果。zBestpracticestoimproverepeatabilityandreproducibilityinbrakeNVHtesting:z提高制动NVH测试可重复性和再现性的最佳操作是：yUsethecorrectlevelofhardware采用正确等级的硬件ySetthecorrecttestparameters设定正确的测试参数yEnsureconsistencyoftestparts确保测试组件的连贯性yDocumentallvariationsandsignificanteventsduringthetest记录测试中所有的变化和重要事件yProperlycollectandanalyzedata适当的收集和分析数据IntroductiontoBrakeNoise&Vibration15ModalTest程式测试zProvidesunderstandingofstructuraldynamiccharacteristicsofthecomponentsandbrakesystem.z提供对部件和制动系统的结构动力学特性的理解zComponentmodaltestmeasuresnaturalfrequencies,modaldampingratios,and/ormodeshapesofpad,rotor,insulator,caliper,anchorbracket,knuckle,etc.z部件程式测试测量了固有频率，程式阻尼比，和/或刹车片，刹车盘，隔振体，卡钳，挂钩，关节等的模态振型。zSystemmodaltestisconductedonbrakesystemonvehicleordynamomet