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ID:50328959
大小:4.45 MB
页数:86页
时间:2020-03-08
《汽车专业英语 教学课件 黄星 刘春波 黄汽驰 6.ppt》由会员上传分享,免费在线阅读,更多相关内容在应用文档-天天文库。
1、UNIT6IntroductiontoBrakeSystemPart ITechnicalandPracticalReadingPassageABrakeSystem(I)Thebreakingsystemisthemostimportantsystemincars.Ifthebrakesdon’tworkeffectively,theresultcanbedisastrous.Sogoodbrakesareessentialforsafety.Thebrakesystemmakesamovingcaronroadslowdownandstop.Thetypicalbrakesyste
2、mconsistsofdiskbrakesinfrontandeitherdiskordrumbrakesintherearconnectedbyasystemoftubesandhosesthatlinkthebrakeateachwheeltothemastercylinder.Seefigure6-1.Figure6-1DiskBrakeThediskbrakesarethebestbrakewehavefoundsofar,andisfastreplacingdrumbrakesontherearwheelsofmoderncars.Thefunctionistocausetwo
3、frictionpadstopressoneithersideofadiskrotatingalongwiththewheel.Thegreatestadvantageofdiskbrakesisthattheyprovidesignificantlybetterresistanceto“brakefade”comparedtodrumtypebrakingsystem.Themaincomponentsofadiskbrakeare:diskorrotor,whichismountedtothehub,brakepads,andcaliper,whichcontainsapiston.
4、Seefigure6-2.Figure6-2DiskBrakeModuleAbrakediskorrotorusuallyismadeofcastironwithhighlymachinedsurfaceswherethebrakepadscontactit.Therearetwobrakepadsthataremountedinthecaliper,oneoneachsideofrotor.Seefigure6-3.Figure6-3Thebrakeliningusedtobemadeprimarilyofasbestosbecauseofitsheatabsorbingpropert
5、iesandquietoperation.Asbestos,however,hasbeenoutlawedduetohealthrisk,sonewmaterialsarebeingused.Therearetwomaintypesofcalipers:floatingcalipersandfixedcalipers.Thesingle-pistonfloating-caliperdiscbrakeisself-centeringandself-adjusting.Thecaliperisabletoslidefromsidetosidesoitwillmovetothecenterea
6、chtimethebrakesareapplied.Also,sincethereisnospringtopullthepadsawayfromthedisk,thepadsalwaysstayinlightcontactwiththerotor.Twopiston-floatingcalipersarefoundonmoreexpensivecarsandcanprovideanimprovedbraking“feel”.Seefigure6-4.Figure6-4Four-piston-fixedcalipersaremountedrigidlytothesupportandaren
7、otallowedtomove.Instead,therearetwopistonsoneachsidethatpressthepadsagainsttherotor.Fourpistoncalipershaveabetterfeelandaremoreefficient,butaremoreexpensivetoproduceandcostmoretoservice.ThistypThistypeofcaliperisusuall
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