汽车英语.docx

汽车英语.docx

《汽车英语.docx》由会员分享，可在线阅读，更多相关《汽车英语.docx（17页珍藏版）》请在冰点文库上搜索。

汽车英语

AutomotiveBelts,Fittings,andHoses

INTRODUCTION

Ontheautomobile,especiallyontheengine,therearemanytypesofbelts,fittings,andhoses.BeltsareusedtoconnecttworotatingshaftstogetheiVarioustypesoffit-tingsarealsousedtoconnecttubesandhosestogether.Thischapterintroducesyoutothebasictypesofbelts,fit-tings,andhosesusedontoday’sautomobiles.Inaddition,serviceinformationisincludedthatshowshowtocheckandchangebelts,fittings,hoses,andtubing.

7.1AUTOMOTIVEBELTS

PURPOSEOFAUTOMOTIVEBELTS

Automotivebeltshavebeenusedforyearstoconnectonerotatingshafttoanother.Astechnologyimproves,stronger,moreflexiblebeltsweredevelopedfornewuses.Thebasicpurposeofusinganautomotivebeltistoconnecttwoshaftsthatarenotnecessarilynexttoeachother.Forexample,iftwoshaftsarenexttoeachotherandoneneedstobedrivenfromtheother,gearscouldbeused.Butwhentheshaftsarefartherapart,beltswillbeused.Inaddition,beltsarequietascomparedtogearsorchains.Theyarealsomuchlessexpensive.

Theuseofautomotivebeltsgivesflexibilitytowhererotatingshaftscanbeplaced.Ontoday’sautomotiveengine,beltsareusedtoturnalternators,powersteeringpumps,waterpumps,air-conditioningcompressors,andvariouspollutionequipment.Figure7-1showsanexampleofcommoncomponentsthatcanbedrivenbybeltsonthefrontofanautomotiveengine.

TYPESOFBELTS

Thereareseveraltypesofbeltsusedonautomotiveengin

Theexacttypeuseddependsonseveralconsideration&

Theseincludethefollowing:

（1）Thedistancebetweenthetworotatingshafts

（2）Thespeedofthebelts.

（3）Theloadonthehelts

FIGURE7-1Thebeltonthefrontofanautomotiveenginecanbeusedtodrivemanycomponentsandaccessories.

FIGURE7-3Dependingonthecarmanufacturer,fromonetofourbeltsmaybeusedtodrivevariouscomponents.

FIGURE7-4Beltsareconstructedwithrubber,FIGURE7-5Thiscoggedtimingbelt

fabric,andmetalcordsstrength.keepthecamshaftandcrankshaftthe

witheachother.

FIGURE7-2Varioustypesofbeltsareusedonautomofiveengines.

（1）Theneedfortimingorkeepingthetwoshaftsintimewitheachother

（2）Thedirectionofrotationbetweenthetwoshafts

（3）Thecostsoftheapplication

（4）Thelengthofservicerequired

CommonbeltsusedontheautomobileareshowninFigure7-2.TheconventionalVbeltisusedtodrivealternatorsonsomecars.Thealternatorneedstobedrivenbythecrankshaftoftheengine.TodothisasimpleVbeltmaybeused.NotethattheVbeltwillnotkeepthetworotatingshaftstimedtogether.Theremaybeslippagebetweenthetwo.TheVbeltisalow-costandeffectivewaytoconnecttworotatingshaftstogether.

ThecoggedVbelthasaseriesofribscutintoit.Theseribshaveatendencytoreduceslippagebetweentworotatingshaftsduringheavierloads.Theserpentinebeltiscorn-montodayonenginesthatrequireseveralrotatingshaftstobeturnedbyasinglebelt.Theserpentinebeltissonamedbecauseitcanbesnakedaroundseveralrotatingshafts.Theserpentinebelthasseveral（usuallyfourtoseven）angledgroovesinthebeltsurface.Thenumberofgroovesisdeterminedbythewidthandloadonthebelt.Thesegroovesincreasethesurfaceareaofthebeltsoslippageisreduced.Inaddition,theserpentinebeltiswideenoughsothatpulleyscanrunoneithersideofthebelt.

BELTSYSTEMS

Eachcarmanufacturermayuseadifferentbeltsystem.Figure7-3showsaone-,two-,three-,andfour-beltsystem.Dependingontheshaftsthatmustberotated,aserpentine/belt,Vbelt,orotherbeltmaybeused.Ineachcase,thecrankshaftisthedrivecomponent,whiletheothercornponentsarethedrivencomponents.Notethatsimilardiagramscanusuallybefoundintheservicemanualorunderthehoodofthecartohelptheservicetechnicianservicebeltsandpulleys...

CUSTOMERCONCERN:

AlternatorLightComesOn

Adriversaysthatwhiledrivinghomefromwork,thealternatorlightcameonsuddenly.Beingonlyafewblocksfromhome,thedrivercontinuedhomeandshutthecaroff.Whatcouldbetheproblem?

SOLUTION:

Oftenthealternatorbeltisdrivenfromthecrankshaft.Sometimesthisbeltisveryhardtosee.ltisaserpentine-typebeltand,ifnotcheckedforcracksandotherdamage,mayeasilybreak.Themostlikelycauseofthisproblemisthatthealternatorbeltbroke.Replacingthealternatorbeltwithanewonewilleasilyfixtheproblem.Inthisparticularcasetheair-conditioningcompressorbeltwillalsohavetoberemovedbecauseitridesontheouterendofthecrankshaftpulley.Thealternatorbeltridesonthecenterofthecrankshaftpulley.

BELTCONSTRUCTION

Variousmaterialsareusedtoensurethatautomotivebeltsarestrong.Allbeltsareconstructedofseveralmaterialsincludingrubber,fabric,andrubber-impregnatedfabric（rubberandfabricmixedtogether）.Also,somebeltsarestrengthenedbyusingreinforcingfabricorsteelcordsin-sidethebelt.Thesematerialshelptoreducestretchandslippageunderheavierloadssuchasaircompressors.Fig-ure7-4showstheinternalmakeupofatypicalVbelt.Notethattherearefiberormetalreinforcementsections,rubber-impregnatedsections,andlaminatedfabricsections.

TIMINGBELTS

Inadditiontothebeltsjustmentioned,manyautomotiveenginesalsouseacoggedtimingbelt.Thepurposeofthecoggedtimingbeltistokeepthecamshaftexactlyintimewiththecrankshaft.Thisisimportantsothatthevalveskeepintimewiththepositionofthepistonduringnormaloperation.Figure7-5showsoneexampleofatimingbeltinplaceontheengine.Thecogsinthebeltactlikeachain,keepingthetworotatingshaftsfromslippingoutoftimewitheachother.

SERVICINGBELTS

Therearemanyimportantthingstoknowaboutservicing.belts.Forexample,whenorderingVbeltsitisveryimportanttoreplaceanexistingdamagedbeltwiththecorrectbelt.Vbeltstypicallyhaveacertainwidthandacertain

FIGURE7-6Alwaysmakesurethereplacementbeltisthecorrectsizerecommendedbythemanufacturer.

pitchorangleoftheV.Figure7-6showsthreeexamplesofVbeltsfittingintoapulley.NotethatthebeltistoonarrowindiagramA,toowideindiagramB,andthecorrectsizeindiagramC.

AVbeltmaybeidentifiedasA,B,C,orD.Theselettersindicatethewidthofthebelt.Aisthenarrowest;Disthewidest.Abeltmayalsobeidentifiedbyitslength.Forexample,A35meansanarrowbeltthatis35inchesinlength.Inaddition,vehiclemanufacturersalwaysprovidepartnumbersforspecificbeltapplications.

Wheninstallingserpentinebeltsalwaysmakesurethebeltisplacedcompletelyonthepulley.ItisveryeasytohavethebeltslightlyoffthepulleyasshowninFigure7-7.Inthetopdrawing,thebeltisinstalledcorrectly.Inthemiddledrawing,thebeltisinstalledtoofarintowardtheengine.Inthebottomdrawing,thebeltisinstalledtoofarout,awayfromtheengine.

FIGURE7-8AlwayscheckbeltsforcrackspeelingOiltearsmsingteethandsoOn.

FIGURE7-7Wheninstallingaserpentinebelt,besuretoinstaWitcorrectlyasshown.

Itisalwaysimportanttochecktheconditionofbeltsontheautomobileengine.Figure7-8showstypicaldamagetoloolcforonautomobilebelts.Problemstolookforin-dudethefollowing:

（1）Cracksinthebelt

（2）Oilsoakedintothebelt

（3）-Glazingcausedbyexcessiveslippage

（4）Tearsorsplits

（5）Peeling

（6）Outerwear

（7）Missingteeth

（8）Insidecracks

（9）.Outsidecracks

Ifthereareanyvisiblecracksinthebelt,itshouldbereplacedimmediately.Infact,mostmanufacturersrecommendthatifonebeltneedsreplacement,allotherbeltsshouldbereplaced.Oftendamagetothebeltcanbebetterobservedifitisheldinbothhandsandthentwisted.Thetwistinghelpstoexposesomeofthepossibleproblemswithabelt.

ADJUSTINGBELTS

Somebeltsmayhaveatensiondevicethatkeepsthematthecorrecttension.Therearemanydesignsofbelt-tensiondevices.Inmostcases,thesetensionersworkagainstthebeltunderspringpressure.Thespring-loadedbelttensionerkeepsaconstantpressureonthebeltduringitsoperation.Itismostcommonlyusedonserpentinebelts.

Otherbelts,however,needtobeadjusted.Itisveryimportantforbeltstobeadjustedcorrectly.Ifabeltistooloose,itislikelytoslip.Thiscausesexcessivewearonthesidesofthebeltandoperatingproblemswiththedrivencomponent.Ontheotherhand,ifabeltistootight,itmaydamagebearingsthatareinthealternator,aircompressor,waterpump,andsoon.Whenabeltistootight,itputspressureonthebearingsinthesecomponents.Thiscausesthebearingstofailprematurely.

CUSTOMERCONCERN:

BeltSqueal

AdriverinaToyotasaysthatwhentheengineisaccelerated,thereisanoticeablesquealfromtheen-ginearea.Whatcouldbeapossibleproblem?

SOLUTION:

Whentheengineisaccelerated,thisputsmoreloadonthebelts.Ifabelthasbecomelooseovertime,itmaybegintosliponlyduringacceleration.Thesquealiscausedbythebeltslippingonthepulleys.Ifthisisthecase,readjustmentofthebeltsmaybenecessary.Alsocheckthebeltsforcracks,oil,peeling,andotherdamage.Theproblemwillmostlikelybesolvedbycorrectlyadjustingthetensiononallofthebelts.Rememberthattheaveragelifespanofabeltisabout5yearsor60,000miles,dependingontheexactapplication,ageofbelt,andsoon.

Belttensioncanbecheckedseveralways.Figure7-9showsonesimplewaytocheckthetensionofat,’picalbelt.Findthelon