汽车专业英语读译教程 第3版 课件 13-U8TA Clutches and Manual Transmissions

UNIT8

CLUTCHES,

MANUALTRANSMISSIONS

ANDDRIVELINE

TEXTA

ClutchesandManualTransmissions

PROFESSIONALENGLISHUNIT7

CLUTCHES,MANUALTRANSMISSIONS

ANDDRIVELINE

TEXTA

ClutchesandManualTransmissions

Clutches

ManualTransmission(M/T)

本次课学习内容本次课学习目标掌握离合器和手动变速器的有关英文专业词汇能够较好地用已知翻译技巧进行课文翻译具有较高的阅读速度NEWWORDStransaxle[ֽtrænz'æksl]n.变速驱动桥neutral['nju:trəl]a.中立的,中性的；n.空档throw-out['θrou'aut]n.抛开，断开，次品，分离bronze[brɔnz]n.青铜,铜像；a.青铜色的bushing['bu∫iŋ]n.轴衬,衬套，套管asbestos[æz'bestəs]n.石棉woven['wouvən]a.编成的，纺织的mold[mould]n.模子,铸型；v.铸[塑]造，模制rivet['rivit]n.铆钉；v.铆接，固定cup[kʌp]n.杯；v.使成杯状segment['segmənt]n.段,节,片，扇形cushion['ku∫ən]n.垫子,软垫,衬垫，缓冲垫[器]revolve[ri'vɔlv]v.(使)旋转,循环出现pinch[pint∫]v.夹紧，挤压，节省seize[si:z]v.挤住，卡住，抓住,逮住,夺取overdrive['ouvə'draiv]n.超速传动（常常简写为O/D）mileage['mailid]n.英里数，里程drop-forge['drɔp'fɔ:d]v.锤锻,落锤锻造spur[spə:]n.正齿washer['wɔ∫ə]n.垫圈,洗衣机,洗碗机，洗涤器clash[klæ∫]v.(使)发出撞击声,猛撞,冲突smash[smæ∫]v.碰撞，猛撞literally['litərəli]ad.照字面意义,逐字地，确确实实地

PHRASESANDEXPRESSIONS

driveline传动系统clutchdisc离合器从动盘pressureplate离合器压盘throw-outbearing分离轴承releasebearing分离轴承pilotbearing导向轴承ballbearing球轴承dualmassflywheel双质量飞轮beconstructedof用…制造splinedhub花键毂

PHRASESANDEXPRESSIONS

releaselever分离杆gearratio传动比reductiongear减速档directdrivegear直接档overdrivegear超速档differentialgear差速器reversegear倒档fuelmileage燃油经济性shiftingmechanism换档机构extensionhousing加长壳，后壳precisionmachinery精密机械

PHRASESANDEXPRESSIONS

endplay轴向间隙clustergear

齿轮组，塔齿轮thrustwasher止推垫片synchronizingmechanism同步机构synchronizedgear同步器，同步机构ClutchesThefunctionoftheclutchassemblyincarsandtruckswithmanualtransmissionsortransaxlesistoconnectordisconnecttheflowofpowerfromtheenginetothedriveline.Althoughtherearemanyvariationsinthedesignofclutches,allworkonthesamebasicprinciple.ClutchPurposeAclutchisamechanismdesignedtoconnectordisconnectpowerfromoneworkingparttoanother.Inavehicle,theclutchisusedtotransmitenginepowerandtodisengagetheengineandtransmissionwhenshiftinggears.Italsoallowstheenginetooperatewhenthevehicleisstoppedwithoutplacingthetransmissioninneutral(outofgear).

ClutchesandManualTransmissions

ClutchConstructionThemodernclutchisasingleplate,drydisc(seeFigure8-1).Itconsistsoffivemajorparts:flywheel,clutchdisc,pressureplateassembly,throw-outbearing,andclutchlinkage.Otherpartswhichmakeuptheclutchassemblyarethetransmissioninputshaftandclutchhousing.ClutchesandManualTransmissionsFigure8-1AtypicalclutchClutchesandManualTransmissionsClutchesandManualTransmissionsFlywheelInadditiontoprovidingabaseforthestarterringgear,theflywheelformsthefoundationonwhichtheotherclutchpartsareattached.Theflywheelusedwithmanualtransmissionsisthicktoenableittoabsorbalargeamountofheatgeneratedbyclutchoperation.Theclutchsideismachinedsmoothtoprovideafrictionsurface.Holesaredrilledintotheflywheeltoprovideameansofmountingtheclutchassembly.Aholeisusuallydrilleddirectlyintotherearofthecrankshaft.Thisholeallowsabearingtobeinstalledinthecenteroftheflywheel.Thebearinginthecenteroftheflywheelwillactasasupportfortheoutboardendofthetransmissioninputshaft.Itisreferredtoasapilotbearing.Thepilotbearingmaybeeitheraballbearingorabronzebushing.ClutchesandManualTransmissionsDualMassFlywheelAdualmassflywheelissometimesusedwithdieselengines.Tohelpabsorbenginepowerstrokepulsations,springsmountedinsidetheflywheelactasashockabsorbingunitwhentheflywheelsectionspartiallycompress,smoothingoutthepowerflow.Theyalsohelptoreducestressontheclutchandtransmissionparts.ClutchDiscTheclutchdiscisroundandconstructedofthin,highqualitysteelwithasplined(grooved)hubplacedinthecenter.Thehubsplinesengagesplinesonthetransmissioninputshaft.Theclutchdisccanmovebackandforthontheshaft,butwhenthediscisturned,theshaftmustturnalso.Bothsidesofitsouteredgearecoveredwithfrictionmaterial.Itisoftenmadeofasbestosorotherhightemperaturematerialandcopperwireseitherwovenormoldedtogether.Itisrivetedtothedisc.ClutchesandManualTransmissionsToassistinsmoothengagement,thediscouteredgesareoftensplitandeachpiececupped.Thefrictionmaterialisrivetedtothesesegments.Whenthedisciscompressed,thesecuppedsegmentsactasaspring-likecushion.PressurePlateTheclutchpressureplatediscisthesameineachtypeofpressureplateassembly.Itismadeofathickpieceofcastironformaximumheatabsorption.Itisroundandaboutthesamediameterastheclutchdisc.Onesideofthepressureplateismachinedsmooth.Thissidewillpresstheclutchdiscfacingareaagainsttheflywheel.Theoutersidehasvariousshapestofacilitateattachmentofspringsandreleasemechanisms.ClutchesandManualTransmissionsReleaseLeverOperatingMechanismThismechanismconsistsofaballbearingnormallyreferredtoasathrow-outbearingorreleasebearing.Thisbearingismountedonasleeveorcollarthatslidesbackandforthonahubthatisanintegralpartofthetransmissionfrontbearingretainer.Thethrow-outbearingisfilledwithgreaseatthefactoryanddoesnotneedserviceduringitsusefullife.Anothertypeofthrow-outbearingisthegraphitetype.Thisbearingemploysaringofgraphitetopressagainstasmoothplatefastenedtotheclutchlevers.Thethrow-outbearingsleeveismovedinandoutbyathrow-outforkorclutchfork.Thisforkisusuallypivotedonaballheadstud.Areturnspringpullstheforkawayfromthepressureplate.ClutchesandManualTransmissionsClutchOperationTheflywheel,clutchcover,releaselevers,andpressureplateallrevolveasasingleunit.Thetransmissioninputshaftandtheclutchdiscaresplinedtogether,forminganotherunit.Theonlytimetheclutchdiscwillturn(vehiclestandingstill)iswhenitispinchedbetweentheflywheelandpressureplate.Whenthereleaseleversdrawthepressureplateawayfromtheflywheel,theclutchdiscwillstandstillwhileeverythingelsecontinuestorevolve.Whenthepressureplatetravelsbacktowardtheflywheel,thediscisseizedandforcedtoturnthetransmissioninputshaft,Figure8-2.a)disengagedb)engagedFigure8-2ClutchoperationsimplifiedClutchesandManualTransmissionsManualTransmission(M/T)TransmissionGearRatiosThemodernmanualtransmissioncanprovidethedriverwithuptosixforwardgearratios.Thereductiongearsprovidegearratiosofapproximately3.5:1(statedas3.5to1)forthelowestgear,toabout1.5:1forthehighest.Thedirectdrivegearhasa1:1gearratio.Theoverdrivegearshaveagearratioofabout0.7:1.Byselectingoneoftheratios,itispossibletooperatethevehicleunderallnormalconditions.Inaddition,torqueismultipliedmorethroughthedifferentialgears.Ratiosvaryfromvehicletovehicle,dependingonenginehorsepowerandvehicleweight.Areversegearisalsoused.Thereverseratioisusuallyabout3:1.Thefive-speedtransmissionhasanoverdriveratio.Theoverdriveratioisincorporatedintonewertransmissionstoincreasefuelmileageandloweremissions.ClutchesandManualTransmissionsFigure8-3TherelativepositionsofthefourshaftsinthetransmissioncaseClutchesandManualTransmissionsClutchesandManualTransmissionsTransmissionConstructionAtypicaltransmissionconsistsofacase,fourshafts,bearings,gears,synchronizers,andashiftingmechanism.Figure8-3showstherelativepositionsofthefourshaftsandtheirgearsinthecase.TransmissionCaseThetransmissioncaseholdsthetransmissiongears,shafts,bearings,andwashers.Itisboltedtotherearoftheengine,ortotheclutchhousing.Manytransmissioncasesandclutchhousingsareone-pieceunits.Mosttransmissioncasesaremadeofcastironoraluminumandhaveaseparateextensionhousing,whichsupportstheoutputshaft.Thishousingmayalsocontainthespeedometergear.Therearenginemountisusuallyattachedtotheextensionhousing.ClutchesandManualTransmissionsTransmissionGearTransmissiongearsaremadeofhighqualitysteel,carefullyheat-treatedtoproducesmooth,hardsurfacegearteethwithasofter,butverytoughinterior[1].Theyaredrop-forged(machinehammeredintoshape)whileredhot.Theteethandothercriticalareasarecutonprecisionmachinery.Theteethontransmissiongearsarecutintospurandhelicalpatterns.Thehelicalgearissuperiorinthatitrunsmorequietlyandisstrongerbecausemoretoothareaisincontact[2].Helicalgearsmustbemountedfirmly,sincethereisatendencyforthemtoslideapartduetothespiralshape.Gearendplayintheclustergearandsomeothergearsandshaftsiscontrolledbytheuseofbronzeandsteelthrustwashers.Thesewashersareinstalledontheendofthegearshaftsbetweenthemovinggearsandthestationarytransmissioncase.ClutchesandManualTransmissionsTheremustbesomeclearancebetweenthegearteethtoallowforlubrication,expansionandpossiblesizeirregularity.Thisclearanceisverysmall(afewthousandthsofaninch).ClutchesandManualTransmissionsSynchronizingMechanismOncethevehicleisinmotion,thedrivelinewillturntheoutputshaftcontinuously.Asaresult,