汽车制动系统汽车车辆类外文翻译、中英文翻译、外文文献翻译.pdf

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外文翻译
AutomobileBrakeSystem
Thebrakingsystemisthemostimportantsystemincars.Ifthebrakesfail,theresultcan
bedisastrous.Brakesareactuallyenergyconversiondevices,whichconvertthekineticenergy
(momentum)ofthevehicleintothermalenergy(heat).Whensteppingonthebrakes,thedriver
commandsastoppingforcetentimesaspowerfulastheforcethatputsthecarinmotion.The
brakingsystemcanexertthousandsofpoundsofpressureoneachofthefourbrakes.
Twocompleteindependentbrakingsystemsareusedonthecar.Theyaretheservicebrake
andtheparkingbrake.
Theservicebrakeactstoslow,stop,orholdthevehicleduringnormaldriving.Theyare
foot-operatedbythedriverdepressingandreleasingthebrakepedal.Theprimarypurposeofthe
brakeistoholdthevehiclestationarywhileitisunattended.Theparkingbrakeismechanically
operatedbywhenaseparateparkingbrakefootpedalorhandleverisset.
Thebrakesystemiscomposedofthefollowingbasiccomponents:the“mastercylinder”
whichislocatedunderthehood,andisdirectlyconnectedtothebrakepedal,convertsdriver
foot’smechanicalpressureintohydraulicpressure.Steel“brakelines”andflexible“brakehoses”

connectthemastercylindertothe“slavecylinders”locatedateachwheel.Brakefluid,specially
designedtoworkinextremeconditions,fillsthesystem.“Shoes”and“pads”arepushedbythe
slavecylinderstocontactthe“drums”and“rotors”thuscausingdrag,which(hopefully)lowssthe
car.
Thetypicalbrakesystemconsistsofdiskbrakesinfrontandeitherdiskordrumbrakesin
therearconnectedbyasystemoftubesandhosesthatlinkthebrakeateachwheeltothemaster
cylinder(Figure).
Basically,allcarbrakesarefrictionbrakes.Whenthedriverappliesthebrake,thecontrol
deviceforcesbrakeshoes,orpads,againsttherotatingbrakedrumordisksatwheel.Friction
betweentheshoesorpadsandthedrumsordisksthenslowsorstopsthewheelsothatthecaris
braked.
Inmostmodernbrakesystems(seeFigure15.1),thereisafluid-filledcylinder,called
mastercylinder,whichcontainstwoseparatesections,thereisapistonineachsectionandboth
pistonsareconnectedtoabrakepedalinthedriver’scompartment.Whenthebrakeispushed
down,brakefluidissentfromt