汽車專業(yè)英語4Brakingsystem

汽車專業(yè)英語

SpecialtyEnglishforAutomobile劉永剛E-mail:

andyliuyg@Telhapter4BrakingsystemFeature:adistinctiveattributeoraspectofsomethingEnergyisrequiredwhenavehicleisacceleratedfromresttoacertainspeed.A

proportion

ofthatenergyisnowstoredinthevehicleandiscalledkineticenergy.Inordertoreducethespeedofthevehicle,thebrakeshavetoconvertthekineticenergytoheatenergy;thespeedofconversiongovernstherateatwhichthevehicleslowsdown.汽車從原地起步(靜止)加速到某一速度需要能量，儲存在汽車中的那部分能量稱為動能。要降低車速,制動器必須把動能轉(zhuǎn)換為熱能；轉(zhuǎn)換的速度決定了汽車減速的快慢。Abrakingsystemconsistsofenergy-supplyingdevice,acontroldevice,atransmissiondeviceandthebrake.供能裝置、控制裝置、傳動裝置、制動器Thethreetypesofbrakingsystemsareinusetoday:servicebrakingsystem,parkingbrakingsystemandadditionalretarding-brakingsystem.Theservicebrakingsystemandtheparkingbrakingsystemhaveseparatecontrolandtransmissiondevices.Theservicebrakingsystemisnormallyfoot-operated,whiletheparkingbrakingsystemishand-operated.行車制動系、駐車制動系、（緩速式）輔助制動系Differentiate：recognizeorascertainwhatmakes(someoneorsomething)differentMuscular-energybrakingsystem:Energy-assistedbrakingsystempowerNon-muscular-energybrakingsystemInertiabrakingsystemGravitybrakingsystemVacuumHydraulicpower人力制動系助力制動系非人力制動系（動力制動系）慣性制動系重力制動系

Drum/discbrakeFrontrearBrakepedalMastercylinderBrakelines/hosesMeteringvalveProportioningvalveWheelvalveDisc//caliperDrumbrakeTwotypesofhydraulicbrakesystemsareused.Themanualbrakesystemisthesimplest.Here,theforceofthedriver’sfootonthepedalappliesalltheforcetothehydraulicsystem.Anothersystem,thepowersystem,usespartsthatassistadrivertothehydraulicsystem.Thereisalsoanantiskidsystemthatpreventsthebrakesfromlockingupthewheelsandcausingskidding.Single-circuitbrakingsystemMulti-circuitbrakingsystemMechanicalHydraulicPneumaticelectrical4.2TypesofbrakesDrumbrakeThesehavetwoshoes,anchoredtoastationaryback-plate,whichareinternallyexpandedtocontactthedrumbyhydrauliccylindersoramechanical

linkage.Anchor:錨泊（車船）；固定stall熄火拋錨LeadingshoeTrailingshoeDifferentdrumbrakedesignsresultfromconsiderationswithregardtoapplication,supportandadjustmentofthebrakeshoes.BrakesareassessedintermsofthebrakefactorC*whichexpressestheratiooflongitudinalforcetotensioningforceatthebrakeshoe.Thebrakefactortakesintoconsiderationtheeffectofthecoefficientoffrictionandtheinternaltransmissionratioofthebrake.Simplexdrumbrakes：單一的Duo-duplexdrumbrakes:雙雙重Duo-servodrumbrakes：伺副増力Incaseofhydraulicbrakingforceactuation,thebrakesareappliedbymeansoffloatingpressurepistonswhosetravelisnotfixed,andwhich

developtensioningforceswhichareequalinbothdirections.Oneofthetwoshoesistheleadingshoe,i.e.thefrictionalforcesbetweenthebrakeliningandthebrakedrumacttosupporttheapplicationforce,whereasthefrictionalforcesinthecaseofthetrailingshoeacttoopposethetensioningforce.Inthecaseofthesimplexbrake,C*(brakefactor)isthesumofthevaluesfortheindividualshoes,andis≈2.0（referredtoaspecificcoefficientoffriction)Adisadvantageofthisdesignisthegreatdifferenceinthebrakingeffectbetweenthetwobrakeshoes,andtheresultinggreatlyincreasedwearontheleadingshoe.

Forthisreason,thetrailingshoeisoftenequippedwithamuchthinnerliningthantheleadingshoe.就領(lǐng)從蹄而言，C*(制動因數(shù))表示各蹄的總和，且≈２.０(特指某一摩擦系數(shù)）．這種設(shè)計的缺點(diǎn)是兩個制動蹄的制動效果差別很大，結(jié)果大大增加了領(lǐng)蹄上的摩擦．因此，從蹄的摩擦襯片比領(lǐng)蹄?。甋implexdrumbrake領(lǐng)從蹄式制動器S-camsimplexdrumbrake凸輪式Advantages:uniformliningwearonleadingandtrailingshoesasaresultoffixedapplication,andresultinglonglininglife.Thistypeofdrumbrakehasanapplicationmechanismwhichissimpler,morereliableandinsensitivetotemperature.Itcomprisesdiaphragmcylinder,automaticslackadjuster,brakeshaftandS-cam.Mediumandheavy-dutytruckThistypeofdrumbrakeischaracterizedbyfloatingapplicationandthecorrespondingnecessaryslidingshoesupport.

Anadvantageofthistypeofbrakeisthenearlyequalbrakeliningwearonbothshoesandthehigherinternaltransmissionratioincomparisontosimplexbrakes.Withtwoleadingshoes,brakefactorsofC*≈3.0areachieved,however,thesefigurescannotbeheldconstantthroughoutalongperiodofbrakingduetothesusceptibilitytofadingofthistypeofbrake.

制動鉗體caliper活塞piston制動塊Frictionpad制動盤discDiscbrakewithfixedcaliper4.2.2DiscbrakeExposedtotheair,discbrakesradiatetheheattotheairbetterthandrumbrakes.Thismeansthatthebrakecanbeoperatedcontinuouslyforalongerperiod,i.e.theyhaveagreaterresistancetofade(fall-offinbrakeefficiencyduetoheat).由于暴露于空氣中，盤式制動器的散熱效果比鼓式好。這意味著盤式制動器能持續(xù)使用更長的時間，也就是說其抗熱衰退性（因受熱導(dǎo)致制動效能下降）要好得多。在許多乘用車上使用的盤式制動器逐漸開始應(yīng)用在商用車上。除快速客車外,盤式制動器在商用車的使用基本限制在的前橋制動系,且整車重量不超過7.5噸，這種商用車的驅(qū)動方式與乘用車相似。Discbrakesasusedinmostpassengercarsareslowlybeginningtobeusedincommercialvehiclesaswell.Asidefromtheiruseinfastcoaches,currentuseofdiscbrakesincommercialvehiclesisprimarilylimitedtofront-axlebrakesforcommercialvehiclesuptoaweightofapprox.7.5twhicharedriveninamannersimilartopassengercars.4.4AntilockbrakingsystemforpassengersAnanti-lockbrakingsystem,orABS(fromtheGerman,Antiblockiersystem)isasafetysystemwhichpreventsthewheelsonamotorvehiclefromlockingwhilebraking.Arotatingroadwheelallowsthedrivertomaintainsteeringcontrolunderheavybrakingbypreventingaskid.WhileABSoffersimprovedvehiclecontrolinsomecircumstances,itcanalsopresentdisadvantagesincludingincreasedbrakingdistanceonslipperysurfacessuchasice,packedsnow,gravel,steelplatesandbridges,oranythingotherthandrypavement.ABShasalsobeendemonstratedtocreateafalsesenseofsecurityindrivers,whomaydrivemoreaggressivelyasaresult.Sinceinitialwidespreaduseinproductioncars,anti-lockbrakingsystemshaveevolvedconsiderably.Recentversionsnotonlypreventwheellockunderbraking,butalsoelectronicallycontrolthefront-to-rearbrakebias.Thisfunction,dependingonitsspecificcapabilitiesandimple