資源描述：
《汽車專業(yè)英語 黃星 劉春波 黃汽馳 6》由會員上傳分享，免費(fèi)在線閱讀，更多相關(guān)內(nèi)容在教育資源-天天文庫。
1、UNIT6IntroductiontoBrakeSystemPart?ITechnicalandPracticalReading?PassageABrakeSystem(I)Thebreakingsystemisthemostimportantsystemincars.Ifthebrakesdon’tworkeffectively,theresultcanbedisastrous.Sogoodbrakesareessentialforsafety.Thebrakesystemmakesamovingcaronroadslo
2、wdownandstop.Thetypicalbrakesystemconsistsofdiskbrakesinfrontandeitherdiskordrumbrakesintherearconnectedbyasystemoftubesandhosesthatlinkthebrakeateachwheeltothemastercylinder.Seefigure6-1.Figure6-1DiskBrakeThediskbrakesarethebestbrakewehavefoundsofar,andisfastrepl
3、acingdrumbrakesontherearwheelsofmoderncars.Thefunctionistocausetwofrictionpadstopressoneithersideofadiskrotatingalongwiththewheel.Thegreatestadvantageofdiskbrakesisthattheyprovidesignificantlybetterresistanceto“brakefade”comparedtodrumtypebrakingsystem.Themaincomp
4、onentsofadiskbrakeare:diskorrotor,whichismountedtothehub,brakepads,andcaliper,whichcontainsapiston.Seefigure6-2.Figure6-2DiskBrakeModuleAbrakediskorrotorusuallyismadeofcastironwithhighlymachinedsurfaceswherethebrakepadscontactit.Therearetwobrakepadsthataremountedi
5、nthecaliper,oneoneachsideofrotor.Seefigure6-3.Figure6-3Thebrakeliningusedtobemadeprimarilyofasbestosbecauseofitsheatabsorbingpropertiesandquietoperation.Asbestos,however,hasbeenoutlawedduetohealthrisk,sonewmaterialsarebeingused.Therearetwomaintypesofcalipers:float
6、ingcalipersandfixedcalipers.Thesingle-pistonfloating-caliperdiscbrakeisself-centeringandself-adjusting.Thecaliperisabletoslidefromsidetosidesoitwillmovetothecentereachtimethebrakesareapplied.Also,sincethereisnospringtopullthepadsawayfromthedisk,thepadsalwaysstayin
7、lightcontactwiththerotor.Twopiston-floatingcalipersarefoundonmoreexpensivecarsandcanprovideanimprovedbraking“feel”.Seefigure6-4.Figure6-4Four-piston-fixedcalipersaremountedrigidlytothesupportandarenotallowedtomove.Instead,therearetwopistonsoneachsidethatpressthepa
8、dsagainsttherotor.Fourpistoncalipershaveabetterfeelandaremoreefficient,butaremoreexpensivetoproduceandcostmoretoservice.ThistypThistypeofcaliperisusuall
