汽車制動(dòng)系統(tǒng)外文翻譯

I中英文文獻(xiàn)翻譯姓名：王奎所在院系：機(jī)械與動(dòng)力工程系專業(yè)班級(jí)：機(jī)械設(shè)計(jì)08-3班學(xué)號(hào)：0828070005指導(dǎo)教師：趙武原文標(biāo)題：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.Finallyin1954Citro?nlaunchedtheway-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.汽車制動(dòng)系統(tǒng)制動(dòng)系統(tǒng)是汽車中最重要的系統(tǒng)。如果制動(dòng)失靈，結(jié)果可能是損失慘重的。制動(dòng)器實(shí)際就是能量轉(zhuǎn)換裝置，它將汽車的動(dòng)能（動(dòng)量）轉(zhuǎn)化成熱能（熱量）。當(dāng)駕駛員踩下制動(dòng)踏板，所產(chǎn)生的制動(dòng)力是汽車運(yùn)動(dòng)時(shí)動(dòng)力的10倍。制動(dòng)系統(tǒng)能對(duì)四個(gè)剎車系統(tǒng)中的每個(gè)施加數(shù)千磅的力。每輛汽車上使用兩個(gè)完全獨(dú)立的制動(dòng)系統(tǒng)，即行車制動(dòng)系和駐車制動(dòng)系。行車制動(dòng)起到減速、停車、或保持車輛正常行駛。制動(dòng)器是由司機(jī)用腳踩、松制動(dòng)器踏板來(lái)控制的。駐車制動(dòng)器的主要作用就是當(dāng)車內(nèi)無(wú)人的時(shí)候，汽車能夠保持靜止。當(dāng)獨(dú)立的駐車制動(dòng)器—踏板或手桿，被安裝時(shí)，駐車制動(dòng)器就會(huì)被機(jī)械地操作。制動(dòng)系統(tǒng)是由下列基本的成分組成:位于發(fā)動(dòng)機(jī)罩下方，而且直接地被連接到制動(dòng)踏板的“制動(dòng)主缸”把駕駛員腳的機(jī)械力轉(zhuǎn)變?yōu)橐簤毫?。鋼制的“制?dòng)管路”和有柔性的“制動(dòng)軟管”把制動(dòng)主缸連接到每個(gè)輪子的“制動(dòng)輪缸”上。制動(dòng)液,特別地設(shè)計(jì)為的是工作在極端的情況，填充在系統(tǒng)中?！爸苿?dòng)盤”和“襯塊”是被制動(dòng)輪缸推動(dòng)接觸“圓盤”和“回轉(zhuǎn)體”如此引起緩慢的拖拉運(yùn)動(dòng),(希望)使汽車減慢速度。典型的制動(dòng)系統(tǒng)布置有前后盤式，前盤后鼓式，各個(gè)車輪上的制動(dòng)器通過一套管路系統(tǒng)連接到制動(dòng)主缸上?；旧现v，所有的汽車制動(dòng)器都是摩擦制動(dòng)器。當(dāng)司機(jī)剎車時(shí)，控制裝置會(huì)迫使制動(dòng)蹄，或制動(dòng)襯片與車輪處的旋轉(zhuǎn)的制動(dòng)鼓或制動(dòng)盤接觸。接觸后產(chǎn)生的摩擦使車輪轉(zhuǎn)動(dòng)減慢或停止，這就是汽車的制動(dòng)。在最基本的制動(dòng)系統(tǒng)中，有一個(gè)制動(dòng)主缸，這個(gè)主缸內(nèi)部填充制動(dòng)液，并包含兩個(gè)部分，每個(gè)部分里都有一個(gè)活塞，兩個(gè)活塞都連接駕駛室里的制動(dòng)踏板。當(dāng)制動(dòng)踏板被踩下時(shí)，制動(dòng)液會(huì)從制動(dòng)主缸流入輪缸。在輪缸中，制動(dòng)液推動(dòng)制動(dòng)蹄或制動(dòng)襯片與旋轉(zhuǎn)的制動(dòng)鼓或制動(dòng)盤接觸。靜止的制動(dòng)蹄或制動(dòng)襯片與旋轉(zhuǎn)的制動(dòng)鼓或制動(dòng)盤之間產(chǎn)生摩擦力使汽車的運(yùn)動(dòng)逐漸減緩或停止。制動(dòng)液的裝置位于主缸的頂部。目前大多數(shù)的車都有一個(gè)容易看見的裝制動(dòng)液的裝置，為的是不用打開蓋子就可以看得見制動(dòng)液的油面。隨著制動(dòng)踏板的運(yùn)動(dòng)制動(dòng)液就會(huì)緩慢的下降，正常情況下是這樣的。如果制動(dòng)液在很短的時(shí)間內(nèi)下降得明顯或者下降了三分之二，那么就要盡快的檢查你的制動(dòng)系統(tǒng)了。保持制動(dòng)液裝置充滿制動(dòng)液除非你需要維修它，制動(dòng)液必須保持很高的沸點(diǎn)。位于在空氣中的制動(dòng)液就會(huì)吸收空氣中的潮氣引起制動(dòng)液低于沸點(diǎn)。制動(dòng)液通過一系列的管路從主缸到達(dá)各車輪。橡膠軟管只用在需要彈力的地方，比如應(yīng)用在前輪。在車的行進(jìn)中上下來(lái)回運(yùn)動(dòng)。系統(tǒng)的其它部分在所有的連接點(diǎn)上都應(yīng)用了無(wú)腐蝕性的無(wú)縫鋼管。如果鋼線需要修理的話，最好的方法就是代替這條線。如果這不符合實(shí)際，那么為了制動(dòng)系統(tǒng)可以用特殊的裝置修理它。你不可以用銅管來(lái)修理制動(dòng)系。它們是危險(xiǎn)也是不正確的。鼓式制動(dòng)器包括制動(dòng)鼓，一個(gè)輪缸，回拉彈簧，一個(gè)制動(dòng)底版，兩個(gè)帶摩擦層的制動(dòng)蹄。制動(dòng)底版固定在輪軸外部的法蘭或轉(zhuǎn)向節(jié)。制動(dòng)鼓固定在輪轂上。制動(dòng)鼓的內(nèi)部表面與制動(dòng)蹄的內(nèi)層之間有空隙。要使用制動(dòng)器時(shí)，司機(jī)就要踩下踏板，這時(shí)輪缸擴(kuò)大制動(dòng)片，對(duì)其施加壓力，是制動(dòng)蹄觸碰制動(dòng)鼓。制動(dòng)鼓與摩擦片之間產(chǎn)生的摩擦制動(dòng)了車輪，從而使汽車停止。要釋放制動(dòng)器時(shí)，司機(jī)松開踏板，回拉彈簧拉回制動(dòng)片，這樣車輪會(huì)自由轉(zhuǎn)動(dòng)。盤式制動(dòng)器包括制動(dòng)盤而不是鼓，在它的兩面上各有一個(gè)薄的制動(dòng)片或叫盤式制動(dòng)器的制動(dòng)片。制動(dòng)片是靠擠住旋轉(zhuǎn)的制動(dòng)盤來(lái)停住汽車。制動(dòng)主缸里流出的制動(dòng)液迫使活塞向里部的金屬盤移動(dòng)，這便使摩擦片緊緊地貼住制動(dòng)盤。這時(shí)制動(dòng)片與制動(dòng)盤產(chǎn)生的摩擦使汽車減速、停止，出現(xiàn)了制動(dòng)行為?；钊纸饘倩蛩芰稀１P式制動(dòng)器主要有三種，即：浮動(dòng)卡鉗型、固定卡鉗型和滑動(dòng)卡鉗型。浮動(dòng)卡鉗型和滑動(dòng)卡鉗型盤式制動(dòng)器使用單活塞。固定卡鉗型盤式制動(dòng)器既可以使用兩個(gè)活塞有可以使用四個(gè)活塞。制動(dòng)器：它們的作用是什么呢？簡(jiǎn)單的說(shuō)：它會(huì)使你的汽車慢下來(lái)。復(fù)雜的說(shuō)：制動(dòng)器被用來(lái)讓你的車減速，但可能不是你所想的意思。普遍的誤解是，制動(dòng)器擠壓制動(dòng)鼓或制動(dòng)片，擠壓的壓力的作用使你的車慢下來(lái)。但這只是制動(dòng)的一部分。制動(dòng)系統(tǒng)本質(zhì)上是改變能量的類型。當(dāng)你在全速行駛時(shí)，你的汽車獲得動(dòng)能。當(dāng)你踩下剎車，墊子或鞋子對(duì)制動(dòng)鼓和轉(zhuǎn)子的作用轉(zhuǎn)化為摩擦熱能。剎車的冷卻使車的熱能消散，減慢車速。這是熱力學(xué)第一定律，有時(shí)被視為能量守恒定律。也是就說(shuō)：能量不能被創(chuàng)造也不能被消滅，只能由一種形式轉(zhuǎn)換成另一種。制動(dòng)情況下，它是動(dòng)能轉(zhuǎn)化為熱能。角向力因?yàn)樵诒P式制動(dòng)器的剎車片和轉(zhuǎn)子的位置，摩擦產(chǎn)生的接觸點(diǎn)的位置也產(chǎn)生了一個(gè)機(jī)械的抵御轉(zhuǎn)子的回轉(zhuǎn)運(yùn)動(dòng)。熱力學(xué)，制動(dòng)失效，鉆孔轉(zhuǎn)子。如果你騎摩托車或駕駛一輛賽車，你或許熟悉制動(dòng)失效，描述當(dāng)制動(dòng)器太熱，他發(fā)生了什么。一個(gè)很好的例子就是從山上下來(lái)使用剎車制動(dòng),而不是你的引擎使你減速。當(dāng)汽車開始滑動(dòng)下來(lái)時(shí)，剎車使汽車產(chǎn)生熱能,使你減速。但是如果你持續(xù)使用他們，轉(zhuǎn)子或鼓留熱并沒有機(jī)會(huì)冷卻。從某種意義上說(shuō)他們不能吸收更多的熱量，使剎車墊熱了起來(lái)。在每一個(gè)墊子的摩擦材料有某種共同的樹脂一旦開始變得太熱，該樹脂開始蒸發(fā)，形成氣。由于氣體之間不能待在墊層及轉(zhuǎn)子，而是形成薄薄的一層在兩個(gè)之間準(zhǔn)備排走。墊失去與轉(zhuǎn)子的接觸，減少摩擦和熱量。這是完全的制動(dòng)失效。典型的補(bǔ)救辦法，將車停了下來(lái)，等待幾分鐘。由于制動(dòng)部件降溫，吸收熱量的原因，下一次您使用剎車的能力，似乎會(huì)好一點(diǎn)。這種類型的制動(dòng)失效在舊車輛更常見。新的車輛往往從剎車墊中減少排氣，但他們?nèi)杂兄苿?dòng)失效。為什么呢？它仍然因?yàn)閯x車墊太熱。猶由于新的剎車墊合成，襯墊的熱傳遞到卡鉗一旦轉(zhuǎn)子太熱了，制動(dòng)液開始沸騰冒泡。因?yàn)榭諝馐强蓧嚎s的(制動(dòng)液不是)當(dāng)你踩剎車，氣泡的壓縮代替了流體轉(zhuǎn)移到制動(dòng)卡鉗。這就是現(xiàn)代制動(dòng)失效。工程師們是怎樣設(shè)計(jì)減少或消除剎車制動(dòng)失效的?年長(zhǎng)的車輛，是使氣化的氣體有地方排掉。新的車輛，找到一些方式來(lái)冷卻轉(zhuǎn)子更為有效。無(wú)論如何你最終獲得交叉鉆孔或溝槽剎車盤。當(dāng)槽表面是可以減少比熱容量的轉(zhuǎn)子，其效果可以忽略不計(jì)的。然而當(dāng)大力剎車時(shí)一旦一切都是熱和樹脂材料蒸發(fā)，槽讓氣體排去，所以墊可以繼續(xù)接觸轉(zhuǎn)子，讓車減速停下來(lái)。整個(gè)的理解能量轉(zhuǎn)換的關(guān)鍵是，剎車他們?cè)撟鍪裁?以及為什么它們?cè)O(shè)計(jì)成這樣。如果你曾看過一級(jí)方程式賽車，你就可以看到向前的前輪里面有很大的洞（如上圖所示）。這是管道空氣剎車部件，以幫助他們冷卻下來(lái)，因?yàn)樵贔1賽車中，剎車每隔幾秒鐘頻繁使用，花很多時(shí)間預(yù)留熱量。如果沒有某種冷卻協(xié)助，剎車就可能在最開始的幾個(gè)轉(zhuǎn)角失靈，最后剎車失效賽車在一半路程出局。轉(zhuǎn)子技術(shù)如果制動(dòng)轉(zhuǎn)子是一個(gè)單一的鋼鐵鑄塊，這將有嚴(yán)重的散熱性能和氣化氣無(wú)法排去。因此，剎車盤通常使用各種額外的設(shè)計(jì)特點(diǎn)的方式來(lái)改進(jìn)幫助他們冷卻下來(lái)，盡快使墊和轉(zhuǎn)子之間的任何氣體排走。這里的圖表顯示了轉(zhuǎn)子類型的各種修改，可以改進(jìn)幫助他們創(chuàng)造更多的摩擦力，更迅速地驅(qū)散更多的熱量，通風(fēng)氣體的一些例子。從左至右。1：基本制動(dòng)轉(zhuǎn)子。2：溝槽轉(zhuǎn)子-溝槽給予更多口，他們之間產(chǎn)生更多的摩擦，還允許氣體從墊和轉(zhuǎn)子之間的排走。3：溝槽鉆孔轉(zhuǎn)子-再給多一點(diǎn)口，但也讓氣流(渦旋)通過制動(dòng)盤協(xié)助冷卻和通風(fēng)。4：雙通風(fēng)轉(zhuǎn)子-以前一樣，然而現(xiàn)在有了兩個(gè)轉(zhuǎn)子而不是一個(gè)，和他們之間葉片產(chǎn)生渦流將進(jìn)一步冷卻轉(zhuǎn)子同時(shí)試圖實(shí)際上從襯墊中排掉任何氣體。重要的一點(diǎn)：鉆孔轉(zhuǎn)子通常只使用于賽車。鉆孔使得轉(zhuǎn)子變?nèi)?，通常?huì)導(dǎo)致轉(zhuǎn)子產(chǎn)生各類裂縫。在賽車中這不是一個(gè)問題——在每場(chǎng)比賽或者每周都會(huì)更換剎車盤。但在路上的車，最終會(huì)導(dǎo)致剎車轉(zhuǎn)子失靈的，不是你能想象的。我只提這件事，因?yàn)橛性S多供應(yīng)商將為您提供鉆孔轉(zhuǎn)子，沒有直接提到這個(gè)事實(shí)。大轉(zhuǎn)子這是如何適用于更大的剎車轉(zhuǎn)子-一種普遍的跑車升級(jí)？汽車和自行車運(yùn)動(dòng)比賽通常有比一般的家庭汽車更大的盤或轉(zhuǎn)子。一個(gè)更大的轉(zhuǎn)子有更多的材料在里面，因此它可以吸收更多的熱量。更多的物質(zhì)也意味著更大的表面積，墊片產(chǎn)生摩擦,和更好的散熱。較大的角度也將轉(zhuǎn)子接觸墊進(jìn)一步遠(yuǎn)離軸旋轉(zhuǎn)。這提供了一個(gè)更大的機(jī)械優(yōu)勢(shì)抵抗旋轉(zhuǎn)的轉(zhuǎn)子本身。這個(gè)工作最好的說(shuō)明，設(shè)想一種紡紗鋼軸上的閥瓣在你的面前。如果你夾緊你的大拇指任何一方的閥瓣靠近中間，你的大拇指將熱得非常快，你會(huì)需要推動(dòng)相當(dāng)大的摩擦力使閥瓣慢下來(lái)?，F(xiàn)在想象做同樣的事情，但是你的大拇指夾在一起接近外緣的閥瓣。閥瓣將停止旋轉(zhuǎn)得特別快，你的大拇指也不會(huì)很熱。簡(jiǎn)單地說(shuō)解釋整個(gè)原理就是更大轉(zhuǎn)子=更好的制動(dòng)原則。不同類型的制動(dòng)器所有制動(dòng)器都產(chǎn)生摩擦力。摩擦力是熱的一部分動(dòng)能轉(zhuǎn)換過程。他們是如何不同的設(shè)計(jì)產(chǎn)生了摩擦的。自行車車輪制動(dòng)器我想我講述這些，因?yàn)樗鼈兪亲罨绢愋偷闹苿?dòng)方式，你可以看到，看工作了解。設(shè)計(jì)非常簡(jiǎn)單，在外部。一雙橡膠塊連接到一雙卡鉗，能在機(jī)架上旋轉(zhuǎn)。當(dāng)你拉剎車線，剎車墊壓向一側(cè)或自行車輪輞的內(nèi)側(cè)邊緣。橡膠產(chǎn)生摩擦，產(chǎn)生熱量，這是動(dòng)能轉(zhuǎn)移使車慢下來(lái)。自行車制動(dòng)實(shí)際上只有兩個(gè)類型-自行車剎車制動(dòng)蹄上有相同的摩擦點(diǎn)，并有兩個(gè)摩擦點(diǎn)。如果你可以看了自行車制動(dòng)，不明白發(fā)生了什么事情，本頁(yè)面的其余部分你理解起來(lái)有麻煩了。鼓式制動(dòng)器——單前沿下一個(gè)，更加復(fù)雜的類型的制動(dòng)是鼓式制動(dòng)器。這是簡(jiǎn)單的概念。兩個(gè)半圓形的剎車片裝在里面連接一個(gè)旋轉(zhuǎn)的車輪的鼓。當(dāng)你踩下剎車,剎車片向