汽车专业英语 教学课件 黄星 刘春波 黄汽驰 6.ppt

《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 ITechnicalandPracticalReadingPassageABrakeSystem(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