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外文出处THEBRAKEBIBLEHTTP/WWWCARBIBLESCOM/BRAKE_BIBLEHTML附件2外文原文THEBRAKEBIBLEBRAKESWHATDOTHEYDOTHESIMPLEANSWERTHEYSLOWYOUDOWNTHECOMPLEXANSWERBRAKESAREDESIGNEDTOSLOWDOWNYOURVEHICLEBUTPROBABLYNOTBYTHEMEANSTHATYOUTHINKTHECOMMONMISCONCEPTIONISTHATBRAKESSQUEEZEAGAINSTADRUMORDISC,ANDTHEPRESSUREOFTHESQUEEZINGACTIONISWHATSLOWSYOUDOWNTHISINFACTISONLYPARTOFTHEEQUATIONBRAKESAREESSENTIALLYAMECHANISMTOCHANGEENERGYTYPESWHENYOURETRAVELLINGATSPEED,YOURVEHICLEHASKINETICENERGYWHENYOUAPPLYTHEBRAKES,THEPADSORSHOESTHATPRESSAGAINSTTHEBRAKEDRUMORROTORCONVERTTHATENERGYINTOTHERMALENERGYVIAFRICTIONTHECOOLINGOFTHEBRAKESDISSIPATESTHEHEATANDTHEVEHICLESLOWSDOWNITSTHEFIRSTLAWOFTHERMODYNAMICS,SOMETIMESKNOWNASTHELAWOFCONSERVATIONOFENERGYTHISSTATESTHATENERGYCANNOTBECREATEDNORDESTROYED,ITCANONLYBECONVERTEDFROMONEFORMTOANOTHERINTHECASEOFBRAKES,ITISCONVERTEDFROMKINETICENERGYTOTHERMALENERGYANGULARFORCEBECAUSEOFTHECONFIGURATIONOFTHEBRAKEPADSANDROTORINADISCBRAKE,THELOCATIONOFTHEPOINTOFCONTACTWHERETHEFRICTIONISGENERATEDALSOPROVIDESAMECHANICALMOMENTTORESISTTHETURNINGMOTIONOFTHEROTORTHERMODYNAMICS,BRAKEFADEANDDRILLEDROTORSIFYOURIDEAMOTORBIKEORDRIVEARACECAR,YOUREPROBABLYFAMILIARWITHTHETERMBRAKEFADE,USEDTODESCRIBEWHATHAPPENSTOBRAKESWHENTHEYGETTOOHOTAGOODEXAMPLEISCOMINGDOWNAMOUNTAINPASSUSINGYOURBRAKESRATHERTHANYOURENGINETOSLOWYOUDOWNASYOUSTARTTOCOMEDOWNTHEPASS,THEBRAKESONYOURVEHICLEHEATUP,SLOWINGYOUDOWNBUTIFYOUKEEPUSINGTHEM,THEROTORSORDRUMSSTAYHOTANDGETNOCHANCETOCOOLOFFATSOMEPOINTTHEYCANTABSORBANYMOREHEATSOTHEBRAKEPADSHEATUPINSTEADINEVERYBRAKEPADTHEREISTHEFRICTIONMATERIALTHATISHELDTOGETHERWITHSOMESORTOFRESINANDONCETHISSTARTSTOGETTOOHOT,THERESINSTARTSTOVAPOURISE,FORMINGAGASBECAUSETHEGASCANTSTAYBETWEENTHEPADANDTHEROTOR,ITFORMSATHINLAYERBETWEENTHETWOWHILSTTRYINGTOESCAPETHEPADSLOSECONTACTWITHTHEROTOR,REDUCINGTHEAMOUNTOFFRICTIONANDVOILACOMPLETEBRAKEFADETHETYPICALREMEDYFORTHISWOULDBETOGETTHEVEHICLETOASTOPANDWAITFORAFEWMINUTESASTHEBRAKECOMPONENTSCOOLDOWN,THEIRABILITYTOABSORBHEATRETURNSANDTHENEXTTIMEYOUUSETHEBRAKES,THEYSEEMTOWORKJUSTFINETHISTYPEOFBRAKEFADEWASMORECOMMONINOLDERVEHICLESNEWERVEHICLESTENDTOHAVELESSOUTGASSINGFROMTHEBRAKEPADCOMPOUNDSBUTTHEYSTILLSUFFERBRAKEFADESOWHYITSSTILLTODOWITHTHEPADSGETTINGTOOHOTWITHNEWERBRAKEPADCOMPOUNDS,THEPADSTRANSFERHEATINTOTHECALIPERSONCETHEROTORSARETOOHOT,ANDTHEBRAKEFLUIDSTARTSTOBOILFORMINGBUBBLESINITBECAUSEAIRISCOMPRESSIBLEBRAKEFLUIDISNTWHENYOUSTEPONTHEBRAKES,THEAIRBUBBLESCOMPRESSINSTEADOFTHEFLUIDTRANSFERRINGTHEMOTIONTOTHEBRAKECALIPERSVOILAMODERNBRAKEFADESOHOWDOTHEENGINEERSDESIGNBRAKESTOREDUCEORELIMINATEBRAKEFADEFOROLDERVEHICLES,YOUGIVETHATVAPOURISEDGASSOMEWHERETOGOFORNEWERVEHICLES,YOUFINDSOMEWAYTOCOOLTHEROTORSOFFMOREEFFECTIVELYEITHERWAYYOUENDUPWITHCROSSDRILLEDORGROOVEDBRAKEROTORSWHILEGROOVINGTHESURFACEMAYREDUCETHESPECIFICHEATCAPACITYOFTHEROTOR,ITSEFFECTISNEGLIGIBLEINTHEGRANDSCHEMEOFTHINGSHOWEVER,UNDERHEAVYBRAKINGONCEEVERYTHINGISHOTANDTHERESINISVAPOURISING,THEGROOVESGIVETHEGASSOMEWHERETOGO,SOTHEPADCANCONTINUETOCONTACTTHEROTOR,ALLOWINGYOUTOSTOPTHEWHOLEUNDERSTANDINGOFTHECONVERSIONOFENERGYISCRITICALINUNDERSTANDINGHOWANDWHYBRAKESDOWHATTHEYDO,ANDWHYTHEYAREDESIGNEDTHEWAYTHEYAREIFYOUVEEVERWATCHEDFORMULA1RACING,YOULLSEETHEFRONTWHEELSHAVEHUGESCOOPSINSIDETHEWHEELPOINTINGTOTHEFRONTSEETHEPICTUREABOVETHISISTODUCTAIRTOTHEBRAKECOMPONENTSTOHELPTHEMCOOLOFFBECAUSEINF1RACING,THEBRAKESAREUSEDVICIOUSLYEVERYFEWSECONDSANDSPENDALOTOFTHEIRTIMETRYINGTOSTAYHOTWITHOUTSOMEFORMOFCOOLINGASSISTANCE,THEBRAKESWOULDBEFINEFORTHEFIRSTFEWCORNERSBUTTHENWOULDFADEANDBECOMENEARUSELESSBYHALFWAYAROUNDTHETRACKROTORTECHNOLOGYIFABRAKEROTORWASASINGLECASTCHUNKOFSTEEL,ITWOULDHAVETERRIBLEHEATDISSIPATIONPROPERTIESANDLEAVENOWHEREFORTHEVAPOURISEDGASTOGOBECAUSEOFTHIS,BRAKEROTORSARETYPICALLYMODIFIEDWITHALLMANNEROFEXTRADESIGNFEATURESTOHELPTHEMCOOLDOWNASQUICKLYASPOSSIBLEASWELLASDISSAPATEANYGASFROMBETWEENTHEPADSANDROTORSTHEDIAGRAMHERESHOWSSOMEEXAMPLESOFROTORTYPESWITHTHEVARIOUSMODIFICATIONTHATCANBEDONETOTHEMTOHELPTHEMCREATEMOREFRICTION,DISPERSEMOREHEATMOREQUICKLY,ANDVENTILATEGASFROMLEFTTORIGHT1BASICBRAKEROTOR2GROOVEDROTORTHEGROOVESGIVEMOREBITEANDTHUSMOREFRICTIONASTHEYPASSBETWEENTHEBRAKEPADSTHEYALSOALLOWGASTOVENTFROMBETWEENTHEPADSANDTHEROTOR3GROOVED,DRILLEDROTORTHEDRILLEDHOLESAGAINGIVEMOREBITE,BUTALSOALLOWAIRCURRENTSEDDIESTOBLOWTHROUGHTHEBRAKEDISCTOASSISTCOOLINGANDVENTILATINGGAS4DUALVENTILATEDROTORSSAMEASBEFOREBUTNOWWITHTWOROTORSINSTEADOFONE,ANDWITHVANESINBETWEENTHEMTOGENERATEAVORTEXWHICHWILLCOOLTHEROTORSEVENFURTHERWHILSTTRYINGTOACTUALLYSUCKANYGASAWAYFROMTHEPADSANIMPORTANTNOTEABOUTDRILLEDROTORSDRILLEDROTORSARETYPICALLYONLYFOUNDANDTOBEUSEDONRACECARSTHEDRILLINGWEAKENSTHEROTORSANDTYPICALLYRESULTSINMICROFRACTURESTOTHEROTORONRACECARSTHISISNTAPROBLEMTHEBRAKESARECHANGEDAFTEREACHRACEORWEEKENDBUTONAROADCAR,THISCANEVENTUALLYLEADTOBRAKEROTORFAILURENOTWHATYOUWANTIONLYMENTIONTHISBECAUSEOFALOTOFPERFORMANCESUPPLIERSWILLSUPPLYYOUWITHDRILLEDROTORSFORSTREETCARSWITHOUTMENTIONINGTHISLITTLEFACTBIGROTORSHOWDOESALLTHISAPPLYTOBIGGERBRAKEROTORSACOMMONSPORTSCARUPGRADESPORTSCARSANDRACEBIKESTYPICALLYHAVEMUCHBIGGER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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