杨四军武科大教授单元四汽车底盘(课件)-《汽车专用英语 第三版》同步教学 （人交版）

汽车商标汽车及其历史汽车发动机汽车底盘单元一单元二单元三单元四汽车电气设备汽车车身汽车使用说明书及维修手册汽车检测与维修设备单元五单元六单元七单元八汽车维护汽车检测与维修新能源汽车概述汽车商务接待单元九单元十单元十一单元十二

单元四

活塞连杆组故障诊断与修复汽车底盘

学习目标

完成本学习任务后，你应该能：1.了解汽车底盘的基本结构与性能;2.掌握汽车底盘各结构术语的英语表达；3.对相关内容进行阅读和翻译；4.对汽车实物上英文单词或词汇进行辨认；5.正确完成课后练习。建议学时4

学时Text

Theautomobilechassisisusedtosupportandinstalltheautomobileengineanditsvariouscomponentsandassemblies,formingthecartheoverallstyling,andacceptingtheenginepowertoproducemovementtoensurethenormaldriving.Theautomotivechassis(Fig.4-1)canbecommonlydividedintofoursystems:thetransmissionsystem,thesuspensionsystem,thesteeringsystemandthebrakingsystem.AnOverviewofAutomobileChassisFig.4-1AutomotiveChassisText

TransmissionSystemThebasictaskoftransmissionsystem(Fig.4-2)istotransmitthepowerfromtheenginetothedrivingwheels.Itmainlyconsistsoftheclutch,transmission(gearbox),propellershaft(universaljoint),differentialanddrivingaxle,etc.AnOverviewofAutomobileChassisFig.4-2TransmissionSystemText

TransmissionSystemClutchisinstalledbetweentheengineandtransmission.Itisafrictiondeviceattachedtotheenginedirectlyinthedriveline.Itspurposeistoprovidesmoothengagementanddisengagementfortheengineandmanualtransmission.Itcontainsapressureplate,clutchdrivenplate,clutchcover,separationlever,releaseyoke,pressurespringandoperatingleversystem.Atransmissionisaspeedandpowerchangingdeviceinstalledatsomepointbetweentheengineanddrivingwheelsofthevehicle.Itisusedtochangetheratiobetweenenginerotatingspeedanddrivingwheelrotatingspeedtobestmeeteachparticulardrivingcondition.AnOverviewofAutomobileChassisText

TransmissionSystemTherearetwotypesoftransmissions：themanualtransmissionandtheautomatictransmission.Inacarwithamanualtransmission,adrivershiftsthegearsmanually,whileinacarwithanautomatictransmission,thegearsshiftautomatically.Thepropellershaft,orthedriveshaft,transmitsthedrivefromthegearboxmainshafttothefinaldrivepinion.Thedifferentialisadevicethatsplitstheenginetorquetwoways,allowingeachoutputtospinatadifferentspeed.Ithasthreefunctions:toaimtheenginepoweratthewhUnitFourAutomobileChassiseels;toactasthefinalgearreductioninthevehicleshowingtherotationalspeedofthetransmissiononefinaltimebeforeithitsthewheels;andtotransmitthepowertothewheelswhileallowingthemtorotateatdifferentspeeds.AnOverviewofAutomobileChassisText

SuspensionSystemThesuspensionsystem(Fig.4-3)coversalltheframestructureswhichareusedtoconnectthewheelsandthebody.Itsupportstheweightoftheengine,transmission,carbodyandwhateverthecarbodyiscarrying.Itsfunctionistoabsorbtheroadshocksandtopreventthemfrombeingtransmittedtotheothercomponentsofthevehicle.Duetothisprovision,othercomponentsbecomesafeduringworkingandtheirlifeisincreased.Thus,thesuspensionsystemmaintainsthestabilityofthevehicleduringpitchingorrollingwhileinmotion.AnOverviewofAutomobileChassisText

SuspensionSystem

AnOverviewofAutomobileChassisFig.4-3SuspensionSystemText

SuspensionSystemTherearetwobasicsuspensionsystemsusedinvehiclestoday.Oneistheintegralaxlswithleafspringtype,theotheristheindependentsuspensionwithlongandshortswingingarms.Therearevariousadaptationsofthesesystems,butallmeetthesamebasicprinciple.Theintegralsuspensioninstallsaleafspringinaone-pieceframesupportshaft(donotturnwiththewheel)ateachside.Thewheelsswiveloneachendviaapivotarrangementbetweentheaxleandthewheelspindle.Withindependentsuspension,eachfrontwheelisfreetomoveupanddownwithaminimum(leastattainable)effectontheotherwheel.Thereisalsofarlesstwistingmotionimposedontheframe.Andalmostallmodernfrontsuspensionsystemsareindependent,whiletherearsuspensionmaybeofthesolidaxleorindependentdesign.AnOverviewofAutomobileChassisText

SuspensionSystem

Mostsuspensionsystemshavethesamebasicparts—springsandshockabsorbersandoperatebasicallyinthesameway.Theydiffer,however,inthetypeandartgementoflinkageusedtoconnectthesepartstotheframeandwheelsandinstallationlocations.AnOverviewofAutomobileChassisText

SteeringSystem

Thesteeringsystem(Fig.4-4)isusedtochangeormaintainthedirectionofdriving.Thedirectionoftheautomobileunderwayischargedbyturningthefrontwheelswiththeaidofthesteeringsystem.Thesteeringsystemincludesasteeringgearandasteeringcontrollinkage.Therotationofthesteeringwheelisimpartedtotheleversandrodsofthelinkagebywhichthesteerablewheelsareturned.Thepurposeofthesteeringsystemisguidingthecarwherethedriverwantsittogo.Itconsistsofsteeringwheel,steeringshaft,worm,gearsector,pitmanarm,draglink,steeringknucklearm,kingpin,steeringarms,tierod,frontaxleandsteeringknuckle.Theyenablethecartochangethedirectionbymeansofturningandmovingforthandback.AnOverviewofAutomobileChassisText

SteeringSystem

AnOverviewofAutomobileChassisFig.4-4SteeringSystemText

SteeringSystem

Therearetwotypesofsteeringsystems:manualsteeringsystemsandpowersteeringsystems.Inthemanualtype,thedriverdoesalltheworkofturningthesteeringwheel,steeringgear,wheels,andtires.Inthepowertype,hydraulicfluidassiststheoperationsothatthedriver'seffortisreduced.AnOverviewofAutomobileChassisText

BrakeSystem

hebrakesystem(Fig.4-5)playsthemostvitalpartduringrunningandcontrolofthemodernvehicles.Inordertobringthemovingvehicletorestorslowdowninashortestpossibletime,theenergyofmotionpossessedbythevehiclemustbeconvertedintosomeotherformofenergy.Brakesystemisinfactanenergyconversiondevice.Whenthedriverforcedtopressdownthedrumbrakes,Thebrakeshoesmadeupoffrictionalmaterialconvertsthekineticenergyofvehiclemotionintothermalpower.AnOverviewofAutomobileChassisText

BrakeSystem

AnOverviewofAutomobileChassisFig.4-5BrakeSystemText

BrakeSystem

Therearetwocompletelyindependentbrakesystemsusedonanautomobile:theservicebrakesystemandtheparkingbrakesystem.Intermsoftheirpowersources,brakesarebasicallyoftwotypes:themechanicallyactuatedbrakesandthehydraulicbrakes.However,thehydraulicbrakeshavebeenuniversallyusedintheservicebrake.Themechanicalbrakesaremainlyusedintheparkingbrake.Mostcarsusedrumbrakesontherearwheels.Inbothdrumanddiscbrakes,ahydraulicsystemappliesthebrakes.Thehydraulicsystemconnectsthebrakepedaltothebrakepartsateachwheel.AnOverviewofAutomobileChassisText

BrakeSystem

Itiswillknownthattheautomobileengineisthepowersourceofanautomobile.Itburnsfuelwithinthecylindersandconvertstheexpandingforceofthecombustionintorotaryforcetopropelthecar.Whereaschassisjustreceivesenginepower,makesitmoveandrunproperlyunderdriver'soperation.Soautomobilechassiswhichiscomposedoftheabovefoursystemsisthemajorconstituentpartofavehicle.AnOverviewofAutomobileChassis参考译文汽车底盘用于支承、安装汽车发动机及其各部件、总成，形成汽车的整体造型，并接受发动机的动力，使汽车产生运动，保证正常行驶。汽车底盘（图4-1）一般可以分为四大系统：传动系统、行驶系统、转向系统和制动系统。汽车底盘概述图4-1汽车底盘参考译文

传动系统传动系统（图4-2）的基本功用是将发动机发出的动力传给汽车的驱动车轮。传动系统一般由离合器、变速器、万向传动装置、主减速器、差速器和半轴等组成。汽车底盘概述图4-2传动系统参考译文

传动系统离合器安装在发动机与变速器之间，是传动系统中与发动机直接连接的一个摩擦装置。它的作用是为发动机和手动换挡变速器提供平缓的啮合和分离。它包括压盘、从动盘、离合器盖、分离杠杆、分离叉、压力弹簧和操纵杆系等。变速器是安装在汽车发动机和驱动轮之间某个位置控制速度和动力的变化装置。它用以改变发动机转速与驱动轮转速间的比率关系使之尽可能地适应各种特定的行车条件。变速器主要有两种类型：手动变速器和自动变速器。在装有手动变速器的汽车上，驾驶员手动操纵挡位，而在装有自动变速器的车上，挡位自动转换。传动轴，又叫驱动轴，它的作用是将变速器主轴的转矩传递到主动齿轮上。差速器是把发动机传来的力矩分成两部分，允许每个输出端以不同的速度转动的装置。它要完成三大任务：将发动机动力传递给车轮；汽车的最后一级减速，将变速器的输出速度再次减速，然后传给车轮；传动到车轮时，允许车轮以不同的速度转动。汽车底盘概述参考译文

行驶系统行驶系统涵盖了用于连接车轮和车身的所有框架结构。它支撑发动机、变速器、汽车车身和一切车身所承载的各总成的质量。它的功用是吸收路面振动并阻止振动传递给汽车的其他零部件。正是由于这种保护作用，其他零部件在工作中才会使用安全从而延长使用年限。因而，行驶系统能使汽车在前进的颠簸或摇晃状态下保持汽车行驶的稳定性。汽车悬架装置（图4-3）主要有两种。一种是使用钢板弹簧的整体式车桥，另一种是使用长短摆臂的独立悬架。虽然分类方式各异，但运用的基本原则却一致。整体式悬架是将钢板弹簧安装在一根整体式的车架支撑轴（不随车轮转动）两端。通过装在车桥和轮轴之间的驱动轴，两端的车轮可以转动。对于独立悬架来说，前轮可以自由上下颠簸行驶而对后轮产生最小的（至少可以承受的）作用，而且车架的扭动也会大大减少。现在几乎所有前悬架系统均为独立式，而后悬架系可为整体式设计也可为独立式设计。汽车底盘概述参考译文

行驶系统大多数行驶系统均采用两种相同的部件——弹簧和减振器，并且工作原理基本一致，但它们用于连接车架和轮胎间各部件的型号以及安装位置上有所差异。汽车底盘概述图4-3悬架装置参考译文

转向系统转向系统（图4-4）用以改变和维持汽车行驶的方向。汽车行驶方向的变化是通过转向系统改变前轮的偏转角度实现的。它包括转向装置和转向控制联动装置。通过旋转转向盘，将偏转角度经联动装置的操作杆传递给转向轮从而改变转向轮的方向。转向系统的作用就是在驾驶员的操纵下控制汽车行驶的方向。它由转向盘、转向轴、万向节蜗杆、转向器、转向摇臂、直拉杆、转向节臂、转向主销、转向臂、横拉杆、前轴和转向节构成。通过这些部件的前后移动或转动，汽车就可以改变行驶方向。汽车的转向有两种：机械转向系统和动力转向系统。其中机械转向系统是完全通过驾驶员的体力转动转向盘、转向器和轮胎完成的。而动力转向系统通过液压助力来帮助汽车的转向操作从而减少驾驶员的体力消耗。汽车底盘概述参考译文

转向系统

汽车底盘概述图4-4转向系统参考译文

制动系统制动系统（图4-5）是现代汽车行驶和控制过程中最重要的系统。为了使行驶的汽车在一段尽可能短的时间内停止或减速，势必要使汽车所具有的动能转化成其他形式的能量。制动系统实际上就是一个能量转换装置。当用力踩下鼓式制动器时，由摩擦材料构成的制动蹄片就将汽车运动的动能转化为热能。汽车底盘概述图4-5制动系统参考译文

制动系统汽车上使用两套完全独立的制动系统：行车制动系统和驻车制动系统。而制动器根据其能量来源的不同又可分为两类：机械制动器和液压制动器。其中液压制动器被广泛运用于各类汽车行车制动系统中，而机械制动器主要用在驻车制动系统中。液压制动系统采用鼓式制动器和盘式制动器，它将制动踏板和每个车轮的制动器部件连在一起。众所周知，汽车发动机是汽车的动力装置，它的作用是使燃料燃烧而产出动力。而底盘则接受发动机的动力，使汽车产生运动，并能在驾驶员的操作下正常行驶。因此，由以上四大系统组成的底盘是汽车最主要的构成部分。汽车底盘概述ReadingMaterialTheanti-lockbrakeisconsideredtobethelatestinnovationandtechnologicalrevolutioninthefieldofamodernautomobilebrakesystem.ABSasitiscommonlyknown,functionswiththehelpofanautomatedandspecializedcomputertoactivatethebrakepumpsatthetimeofpowerfuldecelerationofthewheels.Duringthistime,thewheelswillnotgetlockedandautomobiledriverwillbeabletodrivesafelyandsecurely.Thistypeofsystemfunctionsextremelywellinwet,slipperyoricyconditions,preventingskidsandlossofdirectionalcontrol.Anti-lockBrakeSystem(ABS)ReadingMaterialTheanti-lockbrakesystemcomprisesfourchiefcomponentsnamelywheelspeedsensors,ABSelectroniccontrolunit(ECU),brakepressureregulatingdeviceandbrakecontrolcircuit.Thespeedsensorsaregenerallyinstalledateachwheelandsometimesinthedifferential.TheroleoftheABSECUistocontrolbrakepressureregulatoronthebasisofthespeedsensorsignal.Brakepressureregulatorisinstalledinthebrakemastercylinder,whichisbasedontheinstructionsoftheABSECU,automaticallyadjuststhesizeoftheenginesothatthewheelisinthebestbrakestatus.Brakecontrolcircuitreferstheconductorlinkingwheelspeedsensors,ABSECU,brakingpressureregulator.Anti-lockBrakeSystem(ABS)ReadingMaterialAtpresent,theautomobilemarketisfloodedwiththreebasictypesofABSsuchasfour-channelfour-sensorABS,three-channelthree-sensorABSandone-channelone-sensorABS.Themainfunctionofallofthethreesystemsistopreventwheelsfromgettinglockedupandoffertheshorteststoppingdistanceonslipperyareas.Inordertoenjoythemaximumadvantageofanti-lockbrakesystems,itismandatorytoknowhowtheyoperate.Keepinmindthatwheneveryouaredrivin