会员注册 | 登录 | 微信快捷登录 QQ登录 微博登录 | 帮助中心 人人文库renrendoc.com美如初恋!
站内搜索 百度文库

热门搜索: 直缝焊接机 矿井提升机 循环球式转向器图纸 机器人手爪发展史 管道机器人dwg 动平衡试验台设计

外文翻译---汽车制动系统.doc外文翻译---汽车制动系统.doc -- 5 元

收藏

编号:201311171054075581    大小:332.00KB    格式:DOC    上传时间:2013-11-17
  【编辑】
5
关 键 词:
教育专区 外文翻译 精品文档 外文翻译
资源描述:
1附录1外文翻译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,fillsthe2system.“Shoes”and“pads”arepushedbytheslavecylinderstocontactthe“drums”and“rotors”thuscausingdrag,which(hopefully)slowsthecar.Thetypicalbrakesystemconsistsofdiskbrakesinfrontandeitherdiskordrumbrakesintherearconnectedbyasystemoftubesandhosesthatlinkthebrakeateachwheeltothemastercylinder(Figure).Basically,allcarbrakesarefrictionbrakes.Whenthedriverappliesthebrake,thecontroldeviceforcesbrakeshoes,orpads,againsttherotatingbrakedrumordisksatwheel.Frictionbetweentheshoesorpadsandthedrumsordisksthenslowsorstopsthewheelsothatthecarisbraked.Inmostmodernbrakesystems(seeFigure15.1),thereisafluid-filledcylinder,calledmastercylinder,whichcontainstwoseparatesections,thereisapistonineachsectionandbothpistonsareconnectedtoabrakepedalinthedriver’scompartment.Whenthebrakeispusheddown,brakefluidissentfromthemastercylindertothewheels.Atthewheels,thefluidpushesshoes,orpads,againstrevolvingdrumsordisks.Thefrictionbetweenthestationaryshoes,orpads,andtherevolvingdrumsordisksslowsandstopsthem.Thisslowsorstopstherevolvingwheels,which,inturn,sloworstopthecar.Thebrakefluidreservoirisontopofthemastercylinder.Mostcarstodayhaveatransparentrreservoirsothatyoucanseethelevelwithoutopeningthecover.Thebrakefluidlevelwilldropslightlyasthebrakepadswear.Thisisanormalconditionandnocauseforconcern.Iftheleveldropsnoticeablyoverashortperiodoftimeorgoesdowntoabouttwothirdsfull,haveyourbrakescheckedassoonaspossible.Keepthereservoircoveredexceptfortheamountoftimeyouneedtofillitandneverleaveacamofbrakefluiduncovered.Brakefluidmustmaintainaveryhighboilingpoint.Exposuretoairwillcausethefluidtoabsorbmoisturewhichwilllowerthatboilingpoint.Thebrakefluidtravelsfromthemastercylindertothewheelsthroughaseriesofsteeltubesandreinforcedrubberhoses.Rubberhosesareonlyusedinplacesthatrequireflexibility,suchasatthefrontwheels,whichmoveupanddownaswellassteer.Therestofthesystemusesnon-corrosiveseamlesssteeltubingwithspecialfittingsatallattachmentpoints.Ifasteellinerequiresarepair,thebestprocedureistoreplacethecompeteline.Ifthisisnotpractical,alinecanberepairedusingspecialsplicefittingsthataremadeforbrakesystemrepair.Youmustneverusecoppertubingtorepairabrakesystem.Theyaredangerousandillegal.Drumbrakes,itconsistsofthebrakedrum,anexpander,pullbacksprings,astationarybackplate,twoshoeswithfrictionlinings,andanchorpins.Thestationarybackplateissecuredtotheflangeoftheaxlehousingortothesteeringknuckle.Thebrakedrumismountedonthewheelhub.Thereisaclearancebetweentheinnersurfaceofthedrumandtheshoelining.Toapplybrakes,thedriverpushespedal,the3expanderexpandstheshoesandpressesthemtothedrum.Frictionbetweenthebrakedrumandthefrictionliningsbrakesthewheelsandthevehiclestops.Toreleasebrakes,thedriverreleasethepedal,thepullbackspringretractstheshoesthuspermittingfreerotationofthewheels.Diskbrakes,ithasametaldiskinsteadofadrum.Aflatshoe,ordisk-brakepad,islocatedoneachsideofthedisk.Theshoessqueezetherotatingdisktostopthecar.Fluidfromthemastercylinderforcesthepistonstomovein,towardthedisk.Thisactionpushesthefrictionpadstightlyagainstthedisk.Thefrictionbetweentheshoesanddiskslowsandstopsit.Thisprovidesthebrakingaction.Pistonsaremadeofeitherplasticormetal.Therearethreegeneraltypesofdiskbrakes.Theyarethefloating-calipertype,thefixed-calipertype,andthesliding-calipertype.Floating-caliperandsliding-caliperdiskbrakesuseasinglepiston.Fixed-caliperdiskbrakeshaveeithertwoorfourpistons.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,haveledonemanufacturetostatethatthenumberoftrafficaccidentscouldbe4reducedbysevenandahalfpercentifallcarshadanti-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.Modulatorassembly
温馨提示:
1: 本站所有资源如无特殊说明,都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
2: 本站的文档不包含任何第三方提供的附件图纸等,如果需要附件,请联系上传者。文件的所有权益归上传用户所有。
3.本站RAR压缩包中若带图纸,网页内容里面会有图纸预览,若没有图纸预览就没有图纸。
4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
5. 人人文库网仅提供交流平台,并不能对任何下载内容负责。
6. 下载文件中如有侵权或不适当内容,请与我们联系,我们立即纠正。
7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。
  人人文库网所有资源均是用户自行上传分享,仅供网友学习交流,未经上传用户书面授权,请勿作他用。
0条评论

还可以输入200字符

暂无评论,赶快抢占沙发吧。

当前资源信息

4.0
 
(2人评价)
浏览:25次
英文资料库上传于2013-11-17

官方联系方式

客服手机:13961746681   
2:不支持迅雷下载,请使用浏览器下载   
3:不支持QQ浏览器下载,请用其他浏览器   
4:下载后的文档和图纸-无水印   
5:文档经过压缩,下载后原文更清晰   

相关资源

相关资源

相关搜索

教育专区   外文翻译   精品文档   外文翻译  
关于我们 - 网站声明 - 网站地图 - 友情链接 - 网站客服客服 - 联系我们
copyright@ 2015-2017 人人文库网网站版权所有
苏ICP备12009002号-5