汽车制动系统外文翻译

I中英文文献翻译姓名：王奎所在院系：机械与动力工程系专业班级：机械设计08-3班学号：0828070005指导教师：赵武原文标题：AutomobileBrakeSystem2012年5月25日AutomobileBrakeSystemThebrakingsystemisthemostimportantsystemincars.Ifthebrakesfail,theresultcanbedisastrous.Brakesareactuallyenergyconversiondevices,whichconvertthekineticenergy(momentum)ofthevehicleintothermalenergy(heat).Whensteppingonthebrakes,thedrivercommandsastoppingforcetentimesaspowerfulastheforcethatputsthecarinmotion.Thebrakingsystemcanexertthousandsofpoundsofpressureoneachofthefourbrakes.Twocompleteindependentbrakingsystemsareusedonthecar.Theyaretheservicebrakeandtheparkingbrake.Theservicebrakeactstoslow,stop,orholdthevehicleduringnormaldriving.Theyarefoot-operatedbythedriverdepressingandreleasingthebrakepedal.Theprimarypurposeofthebrakeistoholdthevehiclestationarywhileitisunattended.Theparkingbrakeismechanicallyoperatedbywhenaseparateparkingbrakefootpedalorhandleverisset.Thebrakesystemiscomposedofthefollowingbasiccomponents:the“mastercylinder”whichislocatedunderthehood,andisdirectlyconnectedtothebrakepedal,convertsdriverfoot’smechanicalpressureintohydraulicpressure.Steel“brakelines”andflexible“brakehoses”connectthemastercylindertothe“slavecylinders”locatedateachwheel.Brakefluid,speciallydesignedtoworkinextremeconditions,fillsthesystem.“Shoes”and“pads”arepushedbytheslavecylinderstocontactthe“drums”and“rotors”thuscausingdrag,which(hopefully)slowsthecar.Thetypicalbrakesystemconsistsofdiskbrakesinfrontandeitherdiskordrumbrakesintherearconnectedbyasystemoftubesandhosesthatlinkthebrakeateachwheeltothemastercylinder.Basically,allcarbrakesarefrictionbrakes.Whenthedriverappliesthebrake,thecontroldeviceforcesbrakeshoes,orpads,againsttherotatingbrakedrumordisksatdestroyed,itcanonlybeconvertedfromoneformtoanother.Inthecaseofbrakes,itisconvertedfromkineticenergytothermalenergy.

Angularforce.Becauseoftheconfigurationofthebrakepadsandrotorinadiscbrake,thelocationofthepointofcontactwherethefrictionisgeneratedalsoprovidesamechanicalmomenttoresisttheturningmotionoftherotor.Thermodynamics,brakefadeanddrilledrotors.Ifyourideamotorbikeordrivearacecar,you'reprobablyfamiliarwiththetermbrakefade,usedtodescribewhathappenstobrakeswhentheygettoohot.Agoodexampleiscomingdownamountainpassusingyourbrakesratherthanyourenginetoslowyoudown.Asyoustarttocomedownthepass,thebrakesonyourvehicleheatup,slowingyoudown.Butifyoukeepusingthem,therotorsordrumsstayhotandgetnochancetocooloff.Atsomepointtheycan'tabsorbanymoreheatsothebrakepadsheatupinstead.Ineverybrakepadthereisthefrictionmaterialthatisheldtogetherwithsomesortofresinandoncethisstartstogettoohot,theresinstartstovapourise,formingagas.Becausethegascan'tstaybetweenthepadandtherotor,itformsathinlayerbetweenthetwowhilsttryingtoescape.Thepadslosecontactwiththerotor,reducingtheamountoffrictionandvoila.Completebrakefade.

Thetypicalremedyforthiswouldbetogetthevehicletoastopandwaitforafewminutes.Asthebrakecomponentscooldown,theirabilitytoabsorbheatreturnsandthenexttimeyouusethebrakes,theyseemtoworkjustfine.Thistypeofbrakefadewasmorecommoninoldervehicles.Newervehiclestendtohavelessoutgassingfromthebrakepadcompoundsbuttheystillsufferbrakefade.Sowhy?It'sstilltodowiththepadsgettingtoohot.Withnewerbrakepadcompounds,thepadstransferheatintothecalipersoncetherotorsaretoohot,andthebrakefluidstartstoboilformingbubblesinit.Becauseairiscompressible(brakefluidisn't)whenyousteponthebrakes,theairbubblescompressinsteadofthefluidtransferringthemotiontothebrakecalipers.Voila.Modernbrakefade.

Sohowdotheengineersdesignbrakestoreduceoreliminatebrakefade?Foroldervehicles,yougivethatvapourisedgassomewheretogo.Fornewervehicles,youfindsomewaytocooltherotorsoffmoreeffectively.Eitherwayyouendupwithcross-drilledorgroovedbrakerotors.Whilegroovingthesurfacemayreducethespecificheatcapacityoftherotor,itseffectisnegligibleinthegrandschemeofthings.However,underheavybrakingonceeverythingishotandtheresinisvapourising,thegroovesgivethegassomewheretogo,sothepadcancontinuetocontacttherotor,allowingyoutostop.

Thewholeunderstandingoftheconversionofenergyiscriticalinunderstandinghowandwhybrakesdowhattheydo,andwhytheyaredesignedthewaytheyare.Ifyou'veeverwatchedFormula1racing,you'llseethefrontwheelshavehugescoopsinsidethewheelpointingtothefront(seethepictureabove).ThisistoductairtothebrakecomponentstohelpthemcooloffbecauseinF1racing,thebrakesareusedviciouslyeveryfewsecondsandspendalotoftheirtimetryingtostayhot.Withoutsomeformofcoolingassistance,thebrakeswouldbefineforthefirstfewcornersbutthenwouldfadeandbecomenearuselessbyhalfwayaroundthetrack.Rotortechnology.Ifabrakerotorwasasinglecastchunkofsteel,itwouldhaveterribleheatdissipationpropertiesandleavenowhereforthevapourisedgastogo.Becauseofthis,brakerotorsaretypicallymodifiedwithallmannerofextradesignfeaturestohelpthemcooldownasquicklyaspossibleaswellasdissapateanygasfrombetweenthepadsandrotors.Thediagramhereshowssomeexamplesofrotortypeswiththevariousmodificationthatcanbedonetothemtohelpthemcreatemorefriction,dispersemoreheatmorequickly,andventilategas.Fromlefttoright.1:Basicbrakerotor.2:Groovedrotor-thegroovesgivemorebiteandthusmorefrictionastheypassbetweenthebrakepadsTheyalsoallowgastoventfrombetweenthepadsandtherotor.3:Grooved,drilledrotor-thedrilledholesagaingivemorebite,butalsoallowaircurrents(eddies)toblowthroughthebrakedisctoassistcoolingandventilatinggas.4:Dualventilatedrotors-sameasbeforebutnowwithtworotorsinsteadofone,andwithvanesinbetweenthemtogenerateavortexwhichwillcooltherotorsevenfurtherwhilsttryingtoactually'suck'anygasawayfromthepads.

Animportantnoteaboutdrilledrotors:Drilledrotorsaretypicallyonlyfound(andtobeusedon)racecars.Thedrillingweakenstherotorsandtypicallyresultsinmicrofracturestotherotor.Onracecarsthisisn'taproblem-thebrakesarechangedaftereachraceorweekend.Butonaroadcar,thiscaneventuallyleadtobrakerotorfailure-notwhatyouwant.Ionlymentionthisbecauseofalotofperformancesupplierswillsupplyyouwithdrilledrotorsforstreetcarswithoutmentioningthislittlefact.Bigrotors.Howdoesallthisapplytobiggerbrakerotors-acommonsportscarupgrade?Sportscarsandracebikestypicallyhavemuchbiggerdiscsorrotorsthanyouraveragefamilycar.Abiggerrotorhasmorematerialinitsoitcanabsorbmoreheat.Morematerialalsomeansalargersurfaceareaforthepadstogeneratefrictionwith,andbetterheatdissipation.Largerrotorsalsoputthepointofcontactwiththepadsfurtherawayfromtheaxleofrotation.Thisprovidesalargermechanicaladvantagetoresisttheturningoftherotoritself.Tobestillustratehowthisworks,imagineaspinningsteeldisconanaxleinfrontofyou.Ifyouclampedyourthumbseithersideofthediscclosetothemiddle,yourthumbswouldheatupveryquicklyandyou'dneedtopushprettyhardtogeneratethefrictionrequiredtoslowthediscdown.Nowimaginedoingthesamethingbutclampingyourthumbstogetherclosetotheouterrimofthedisc.Thediscwillstopspinningmuchmorequicklyandyourthumbswon'tgetashot.That,inanutshellexplainsthewholeprinciplebehindwhybiggerrotors=betterstoppingpower.Thedifferenttypesofbrake.Allbrakesworkbyfriction.Frictioncausesheatwhichispartofthekineticenergyconversionprocess.Howtheycreatefrictionisdowntothevariousdesigns.BicyclewheelbrakesIthoughtI'dcoverthesebecausethey'reaboutthemostbasictypeoffunctioningbrakethatyoucansee,watchworking,andunderstand.Theconstructionisverysimpleandout-in-the-open.Apairofrubberblocksareattachedtoapairofcaliperswhicharepivotedontheframe.Whenyoupullthebrakecable,thepadsarepressedagainstthesideorinneredgeofthebicyclewheelrim.Therubbercreatesfriction,whichcreatesheat,whichisthetransferofkineticenergythatslowsyoudown.There'sonlyreallytwotypesofbicyclebrake-thoseonwhicheachbrakeshoesharesthesamepivotpoint,andthosewithtwopivotpoints.Ifyoucanlookatabicyclebrakeandnotunderstandwhat'sgoingon,therestofthispageisgoingtocauseyouabitofaheadache.Drumbrakes-singleleadingedgeThenext,morecomplicatedtypeofbrakeisadrumbrake.Theconcepthereissimple.Twosemicircularbrakeshoessitinsideaspinningdrumwhichisattachedtothewheel.Whenyouapplythebrakes,theshoesareexpandedoutwardstopressagainsttheinsideofthedrum.Thiscreatesfriction,whichcreatesheat,whichtransferskineticenergy,whichslowsyoudown.Theexamplebelowshowsasimplemodel.Theactuatorinthiscaseistheblueellipticalobject.Asthatistwisted,itforcesagainstthebrakeshoesandinturnforcesthemtoexpandoutwards.Thereturnspringiswhatpullstheshoesbackawayfromthesurfaceofthebrakedrumwhenthebrakesarereleased.Seethelatersectionformoreinformationonactuatortypes.The"singleleadingedge"referstothenumberofpartsofthebrakeshoewhichactuallycontactthespinningdrum.Becausethebrakeshoepivotsatoneend,simplegeometrymeansthattheentirebrakepadcannotcontactthebrakedrum.Theleadingedgeisthetermgiventothepartofthebrakepadwhichdoescontactthedrum,andinthecaseofasingleleadingedgesystem,it'sthepartofthepadclosesttotheactuator.Thisdiagram(right)showswhathappensasthebrakesareapplied.Theshoesarepressedoutwardsandthepartofthebrakepadwhichfirstcontactsthedrumistheleadingedge.Theactionofthedrumspinningactuallyhelpstodrawthebrakepadoutwardsbecauseoffriction,whichcausesthebrakesto"bite".Thetrailingedgeofthebrakeshoemakesvirtuallynocontactwiththedrumatall.Thissimplegeometryexplainswhyit'sreallydifficulttostopavehiclerollingbackwardsifit'sequippedonlywithsingleleadingedgedrumbrakes.Asthedrumspinsbackwards,theleadingedgeoftheshoebecomesthetrailingedgeandthusdoesn'tbite.Drumbrakes-doubleleadingedgeThedrawbacksofthesingleleadingedgestyleofdrumbrakecanbeeliminatedbyaddingasecondreturnspringandturningthepivotpointintoasecondactuator.Nowwhenthebrakesareapplied,theshoesarepressedoutwardsattwopoints.Soeachbrakepadnowhasoneleadingandonetrailingedge.Becausetherearetwobrakeshoes,therearetwobrakepads,whichmeanstherearetwoleadingedges.Hencethenamedoubleleadingedge.DiscbrakesSomebackground.Discbrakeswereinventedin1902andpatentedbyBirminghamcarmakerFrederickWilliamLanchester.Hisoriginaldesignhadtwodiscswhichpressedagainsteachothertogeneratefrictionandslowhiscardown.Itwasn'tuntil1949thatdiscbrakesappearedonaproductioncarthough.TheobscureAmericancarbuilderCrosleymadeavehiclecalledtheHotshotwhichusedthemorefamiliarbrakerotorandcalipersthatweallknowandlovetoday.Hisoriginaldesignwasabitcrapthough-thebrakeslastedlessthanayeareach.Finallyin1954Citroënlaunchedtheway-ahead-of-its-timeDSwhichhadthefirstmodernincarnationofdiscbrakesalongwithotherniftystufflikeself-levellingsuspension,semi-automaticgearbox,activeheadlightsandcompositebodypanels.(allthingswhichwerere-introducedas"new"bycarmakersinthe90’s).Discbrakesareanorderofmagnitudebetteratstoppingvehiclesthandrumbrakes,whichiswhyyou'llfinddiscbrakesonthefrontofalmosteverycarandmotorbikebuilttoday.Sportiervehicleswithhigherspeedsneedbetterbrakestoslowthemdown,soyou'lllikelyseediscbrakesontherearofthosetoo.Thebrakesystemassembliesareactuatedbymechanical,hydraulicorpneumaticdevices.Themechanicalleverageisusedintheparkingbrakesfittedinallautomobile.Whenthebrakepedalisdepressed,therodpushesthepistonofbrakemastercylinderwhichpressesthefluid.Thefluidflowsthroughthepipelinestothepowerbrakeunitandthentothewheelcylinder.Thefluidpressureexpandsthecylinderpistonsthuspressingtheshoestothedrumordisk.Ifthepedalisreleased,thepistonreturnstotheinitialposition,thepullbackspringsretracttheshoes,thefluidisforcedbacktothemastercylinderandbrakingceases.Theprimarypurposeoftheparkingbrakeistoholdthevehiclestationarywhileitisunattended.Theparkingbrakeismechanicallyoperatedbythedriverwhenaseparateparkingbrakinghandleverisset.Thehandbrakeisnormallyusedwhenthecarhasalreadystopped.Aleverispulledandtherearbrakesareapproachedandlockedinthe“on”position.Thecarmaynowbeleftwithoutfearofitsrollingaway.Whenthedriverwantstomovethecaragain,hemustpressabuttonbeforethelevercanbereleased.Thehandbrakemustalsobeabletostopthecarintheeventofthefootbrakefailing.Forthisreason,itisseparatefromthefootbrakeusescableorrodsinsteadofthehydraulicsystem.Anti-lockBrakeSystemAnti-lockbrakesystemsmakebrakingsaferandmoreconvenient,Anti-lockbrakesystemsmodulatebrakesystemhydraulicpressuretopreventthebrakesfromlockingandthetiresfromskiddingonslipperypavementorduringapanicstop.Anti-lockbrakesystemshavebeenusedonaircraftforyears,andsomedomesticcarwereofferedwithanearlyformofanti-lockbrakinginlate1990’s.Recently,severalautomakershaveintroducedmoresophisticatedanti-locksystem.InvestigationsinEurope,whereanti-lockbrakingsystemshavebeenavailableforadecade,haveledonemanufacturetostatethatthenumberoftrafficaccidentscouldbereducedbysevenandahalfpercentifallcarshadanti-lockbrakes.Sosomesourcespredictthatallcarswillofferanti-lockbrakestoimprovethesafetyofthecar.

Anti-locksystemsmodulatebrakeapplicationforceseveraltimespersecondtoholdthetiresatacontrolledamountofslip;allsystemsaccomplishthisinbasicallythesameway.Oneormorespeedsensorsgeneratealternatingcurrentsignalwhosefrequencyincreaseswiththewheelrotationalspeed.Anelectroniccontrolunitcontinuouslymonitorsthesesignalsandifthefrequencyofasignaldropstoorapidlyindicatingthatawheelisabouttolock,thecontrolunitinstructsamodulatingdevicetoreducehydraulicpressuretothebrakeattheaffectedwheel.Whensensorsignalsindicatethewheelisagainrotatingnormally,thecontrolunitallowsincreasedhydraulicpressuretothebrake.Thisrelease-applycycleoccursseveraltimepersecondto“pump”thebrakeslikeadrivermightbutatamuchfasterrate.Inadditiontotheirbasicoperation,anti-locksystemshavetwootherthingsincommon.First,theydonotoperateuntilthebrakesareappliedwithenoughforcetolockornearlylockawheel.Atallothertimes,thesystemstandsreadytofunctionbutdoesnotinterferewithnormalbraking.Second,iftheanti-locksystemfailinanyway,thebrakescontinuetooperatewithoutanti-lockcapability.Awarninglightontheinstrumentpanelalertsthedriverwhenaproblemexistsintheanti-locksystem.ThecurrentBoschcomponentAnti-lockBrakingSystem(ABSⅡ),isasecondgenerationdesignwildlyusedbyEuropeanautomakerssuchasBWM,Mercedes-BenzandPorsche.ABSⅡsystemconsistsof:fourwheelspeedsensor,electroniccontrolunitandmodulatorassembly.Aspeedsensorisfittedateachwheelsendssignalsaboutwheelrotationtocontrolunit.Eachspeedsensorconsistsofasensorunitandagearwheel.Thefrontsensormountstothesteeringknuckleanditsgearwheelispressedontothestubaxlethatrotateswiththewheel.Therearsensormountstherearsuspensionmemberanditsgearwheelispressedontotheaxle.Thesensoritselfisawindingwithamagneticcore.Thecorecreatesamagneticfieldaroundthewinding,andastheteethofthegearwheelmovethroughthisfield,analternatingcurrentisinducedinthewinding.Thecontrolunitmonitorstherateochangeinthisfrequencytodetermineimpendingbrakelockup.Thecontrolunit’sfunctioncanbedividedintothreeparts:signalprocessing,logicandsafetycircuitry.Thesignalprocessingsectionistheconverterthatreceivesthealternatingcurrentsignalsformthespeedsensorsandconvertsthemintodigitalformforthelogicsection.Thelogicsectionthenanalyzesthedigitizedsignalstocalculateanybrakepressurechangesneeded.Ifimpendinglockupissensed,thelogicsectionsendscommandstothemodulatorassembly.ModulatorassemblyThehydraulicmodulatorassemblyregulatespressuretothewheelbrakeswhenitreceivescommandsfromthecontrolutuit.Themodulatorassemblycanmaintainorreducepressureoverthelevelitreceivesfromthemastercylinder,italsocanneverapplythebrakesbyitself.Themodulatorassemblyconsistsofthreehigh-speedelectricsolenoidvalves,twofluidreservoirsandaturndeliverypumpequippedwithinletandoutletcheckvalves.Themodulatorelectricalconnectorandcontrollingrelaysareconcealedunderaplasticcoveroftheassembly.Eachfrontwheelisservedbyelectricsolenoidvalvemodulatedindependentlybythecontrolunit.Therearbrakesareservedbyasinglesolenoidvalveandmodulatedtogetherusingtheselect-lowprinciple.Duringanti-brakingsystemoperation,thecontrolunitcyclesthesolenoidvalvestoeitherholdorreleasepressurethebrakelines.Whenpressureisreleasedfromthebrakelinesduringanti-brakingoperation,itisroutedtoafluidreservoir.Thereisonereservoirforthefrontbrakecircuit.Thereservoirsarelow-pressureaccumulatorsthatstorefluidunderslightspringpressureuntilthereturndeliverypumpcanreturnthefluidthroughthebrakelinestothemastercylinder.汽车制动系统制动系统是汽车中最重要的系统。如果制动失灵，结果可能是损失惨重的。制动器实际就是能量转换装置，它将汽车的动能（动量）转化成热能（热量）。当驾驶员踩下制动踏板，所产生的制动力是汽车运动时动力的10倍。制动系统能对四个刹车系统中的每个施加数千磅的力。每辆汽车上使用两个完全独立的制动系统，即行车制动系和驻车制动系。行车制动起到减速、停车、或保持车辆正常行驶。制动器是由司机用脚踩、松制动器踏板来控制的。驻车制动器的主要作用就是当车内无人的时候，汽车能够保持静止。当独立的驻车制动器—踏板或手杆，被安装时，驻车制动器就会被机械地操作。制动系统是由下列基本的成分组成:位于发动机罩下方，而且直接地被连接到制动踏板的“制动主缸”把驾驶员脚的机械力转变为液压力。钢制的“制动管路”和有柔性的“制动软管”把制动主缸连接到每个轮子的“制动轮缸”上。制动液,特别地设计为的是工作在极端的情况，填充在系统中。“制动盘”和“衬块”是被制动轮缸推动接触“圆盘”和“回转体”如此引起缓慢的拖拉运动,(希望)使汽车减慢速度。典型的制动系统布置有前后盘式，前盘后鼓式，各个车轮上的制动器通过一套管路系统连接到制动主缸上。基本上讲，所有的汽车制动器都是摩擦制动器。当司机刹车时，控制装置会迫使制动蹄，或制动衬片与车轮处的旋转的制动鼓或制动盘接触。接触后产生的摩擦使车轮转动减慢或停止，这就是汽车的制动。在最基本的制动系统中，有一个制动主缸，这个主缸内部填充制动液，并包含两个部分，每个部分里都有一个活塞，两个活塞都连接驾驶室里的制动踏板。当制动踏板被踩下时，制动液会从制动主缸流入轮缸。在轮缸中，制动液推动制动蹄或制动衬片与旋转的制动鼓或制动盘接触。静止的制动蹄或制动衬片与旋转的制动鼓或制动盘之间产生摩擦力使汽车的运动逐渐减缓或停止。制动液的装置位于主缸的顶部。目前大多数的车都有一个容易看见的装制动液的装置，为的是不用打开盖子就可以看得见制动液的油面。随着制动踏板的运动制动液就会缓慢的下降，正常情况下是这样的。如果制动液在很短的时间内下降得明显或者下降了三分之二，那么就要尽快的检查你的制动系统了。保持制动液装置充满制动液除非你需要维修它，制动液必须保持很高的沸点。位于在空气中的制动液就会吸收空气中的潮气引起制动液低于沸点。制动液通过一系列的管路从主缸到达各车轮。橡胶软管只用在需要弹力的地方，比如应用在前轮。在车的行进中上下来回运动。系统的其它部分在所有的连接点上都应用了无腐蚀性的无缝钢管。如果钢线需要修理的话，最好的方法就是代替这条线。如果这不符合实际，那么为了制动系统可以用特殊的装置修理它。你不可以用铜管来修理制动系。它们是危险也是不正确的。鼓式制动器包括制动鼓，一个轮缸，回拉弹簧，一个制动底版，两个带摩擦层的制动蹄。制动底版固定在轮轴外部的法兰或转向节。制动鼓固定在轮毂上。制动鼓的内部表面与制动蹄的内层之间有空隙。要使用制动器时，司机就要踩下踏板，这时轮缸扩大制动片，对其施加压力，是制动蹄触碰制动鼓。制动鼓与摩擦片之间产生的摩擦制动了车轮，从而使汽车停止。要释放制动器时，司机松开踏板，回拉弹簧拉回制动片，这样车轮会自由转动。盘式制动器包括制动盘而不是鼓，在它的两面上各有一个薄的制动片或叫盘式制动器的制动片。制动片是靠挤住旋转的制动盘来停住汽车。制动主缸里流出的制动液迫使活塞向里部的金属盘移动，这便使摩擦片紧紧地贴住制动盘。这时制动片与制动盘产生的摩擦使汽车减速、停止，出现了制动行为。活塞分金属或塑料。盘式制动器主要有三种，即：浮动卡钳型、固定卡钳型和滑动卡钳型。浮动卡钳型和滑动卡钳型盘式制动器使用单活塞。固定卡钳型盘式制动器既可以使用两个活塞有可以使用四个活塞。制动器：它们的作用是什么呢？简单的说：它会使你的汽车慢下来。复杂的说：制动器被用来让你的车减速，但可能不是你所想的意思。普遍的误解是，制动器挤压制动鼓或制动片，挤压的压力的作用使你的车慢下来。但这只是制动的一部分。制动系统本质上是改变能量的类型。当你在全速行驶时，你的汽车获得动能。当你踩下刹车，垫子或鞋子对制动鼓和转子的作用转化为摩擦热能。刹车的冷却使车的热能消散，减慢车速。这是热力学第一定律，有时被视为能量守恒定律。也是就说：能量不能被创造也不能被消灭，只能由一种形式转换成另一种。制动情况下，它是动能转化为热能。角向力因为在盘式制动器的刹车片和转子的位置，摩擦产生的接触点的位置也产生了一个机械的抵御转子的回转运动。热力学，制动失效，钻孔转子。如果你骑摩托车或驾驶一辆赛车，你或许熟悉制动失效，描述当制动器太热，他发生了什么。一个很好的例子就是从山上下来使用刹车制动,而不是你的引擎使你减速。当汽车开始滑动下来时，刹车使汽车产生热能,使你减速。但是如果你持续使用他们，转子或鼓留热并没有机会冷却。从某种意义上说他们不能吸收更多的热量，使刹车垫热了起来。在每一个垫子的摩擦材料有某种共同的树脂一旦开始变得太热，该树脂开始蒸发，形成气。由于气体之间不能待在垫层及转子，而是形成薄薄的一层在两个之间准备排走。垫失去与转子的接触，减少摩擦和热量。这是完全的制动失效。典型的补救办法，将车停了下来，等待几分钟。由于制动部件降温，吸收热量的原因，下一次您使用刹车的能力，似乎会好一点。这种类型的制动失效在旧车辆更常见。新的车辆往往从刹车垫中减少排气，但他们仍有制动失效。为什么呢？它仍然因为刹车垫太热。犹由于新的刹车垫合成，衬垫的热传递到卡钳一旦转子太热了，制动液开始沸腾冒泡。因为空气是可压缩的(制动液不是)当你踩刹车，气泡的压缩代替了流体转移到制动卡钳。这就是现代制动失效。工程师们是怎样设计减少或消除刹车制动失效的?年长的车辆，是使气化的气体有地方排掉。新的车辆，找到一些方式来冷却转子更为有效。无论如何你最终获得交叉钻孔或沟槽刹车盘。当槽表面是可以减少比热容量的转子，其效果可以忽略不计的。然而当大力刹车时一旦一切都是热和树脂材料蒸发，槽让气体排去，所以垫可以继续接触转子，让车减速停下来。整个的理解能量转换的关键是，刹车他们该做什么,以及为什么它们设计成这样。如果你曾看过一级方程式赛车，你就可以看到向前的前轮里面有很大的洞（如上图所示）。这是管道空气刹车部件，以帮助他们冷却下来，因为在F1赛车中，刹车每隔几秒钟频繁使用，花很多时间预留热量。如果没有某种冷却协助，刹车就可能在最开始的几个转角失灵，最后刹车失效赛车在一半路程出局。转子技术如果制动转子是一个单一的钢铁铸块，这将有严重的散热性能和气化气无法排去。因此，刹车盘通常使用各种额外的设计特点的方式来改进帮助他们冷却下来，尽快使垫和转子之间的任何气体排走。这里的图表显示了转子类型的各种修改，可以改进帮助他们创造更多的摩擦力，更迅速地驱散更多的热量，通风气体的一些例子。从左至右。1：基本制动转子。2：沟槽转子-沟槽给予更多口，他们之间产生更多的摩擦，还允许气体从垫和转子之间的排走。3：沟槽钻孔转子-再给多一点口，但也让气流(涡旋)通过制动盘协助冷却和通风。4：双通风转子-以前一样，然而现在有了两个转子而不是一个，和他们之间叶片产生涡流将进一步冷却转子同时试图实际上从衬垫中排掉任何气体。重要的一点：钻孔转子通常只使用于赛车。钻孔使得转子变弱，通常会导致转子产生各类裂缝。在赛车中这不是一个问题——在每场比赛或者每周都会更换刹车盘。但在路上的车，最终会导致刹车转子失灵的，不是你能想象的。我只提这件事，因为有许多供应商将为您提供钻孔转子，没有直接提到这个事实。大转子这是如何适用于更大的刹车转子-一种普遍的跑车升级？汽车和自行车运动比赛通常有比一般的家庭汽车更大的盘或转子。一个更大的转子有更多的材料在里面，因此它可以吸收更多的热量。更多的物质也意味着更大的表面积，垫片产生摩擦,和更好的散热。较大的角度也将转子接触垫进一步远离轴旋转。这提供了一个更大的机械优势抵抗旋转的转子本身。这个工作最好的说明，设想一种纺纱钢轴上的阀瓣在你的面前。如果你夹紧你的大拇指任何一方的阀瓣靠近中间，你的大拇指将热得非常快，你会需要推动相当大的摩擦力使阀瓣慢下来。现在想象做同样的事情，但是你的大拇指夹在一起接近外缘的阀瓣。阀瓣将停止旋转得特别快，你的大拇指也不会很热。简单地说解释整个原理就是更大转子=更好的制动原则。不同类型的制动器所有制动器都产生摩擦力。摩擦力是热的一部分动能转换过程。他们是如何不同的设计产生了摩擦的。自行车车轮制动器我想我讲述这些，因为它们是最基本类型的制动方式，你可以看到，看工作了解。设计非常简单，在外部。一双橡胶块连接到一双卡钳，能在机架上旋转。当你拉刹车线，刹车垫压向一侧或自行车轮辋的内侧边缘。橡胶产生摩擦，产生热量，这是动能转移使车慢下来。自行车制动实际上只有两个类型-自行车刹车制动蹄上有相同的摩擦点，并有两个摩擦点。如果你可以看了自行车制动，不明白发生了什么事情，本页面的其余部分你理解起来有麻烦了。鼓式制动器——单前沿下一个，更加复杂的类型的制动是鼓式制动器。这是简单的概念。两个半圆形的刹车片装在里面连接一个旋转的车轮的鼓。当你踩下刹车,刹车片向