机械专业外文翻译自动变速器的工作原理分析解析

1、HowAutomaticTransmissionsWorkbyKarimNiceIntroductiontoHowAutomaticTransmissionsWorkIfyouhaveeverdrivenacarwithanautomatictransmission,thenyouknowthattherearetwobigdifferencesbetweenanautomatictransmissionandamanualtransmission:Thereisnoclutchpedalinanautomatictransmissioncar.Thereisnogearshiftinanau

2、tomatictransmissioncar.Onceyouputthetransmissionintodrive,everythingelseisautomatic.Boththeautomatictransmission(plusitstorqueconverter)andamanualtransmission(withitsclutch)accomplishexactlythesamething,buttheydoitintotallydifferentways.Itturnsoutthatthewayanautomatictransmissiondoesitisabsolutelyam

3、azing!AutomaticTransmissionImageGalleryAutomaticTransmissionInthisarticle,we'llworkourwaythroughanautomatictransmission.We'llstartwiththekeytothewholesystem:planetarygearsets.Thenwe'llseehowthetransmissionisputtogether,learnhowthecontrolsworkanddiscusssomeoftheintricaciesinvolvedincontro

4、llingatransmission.Justlikethatofamanualtransmission,theautomatictransmission'sprimaryjobistoallowtheenginetooperateinitsnarrowrangeofspeedswhileprovidingawiderangeofoutputspeeds.PhotocourtesyDaimlerChryslerMercedes-BenzCLK,automatictransmission,cut-awaymodelWithoutatransmission,carswouldbelimit

5、edtoonegearratio,andthatratiowouldhavetobeselectedtoallowthecartotravelatthedesiredtopspeed.Ifyouwantedatopspeedof80mph,thenthegearratiowouldbesimilartothirdgearinmostmanualtransmissioncars.You'veprobablynevertrieddrivingamanualtransmissioncarusingonlythirdgear.Ifyoudid,you'dquicklyfindoutth

6、atyouhadalmostnoaccelerationwhenstartingout,andathighspeeds,theenginewouldbescreamingalongnearthered-line.Acarlikethiswouldwearoutveryquicklyandwouldbenearlyundriveable.Sothetransmissionusesgearstomakemoreeffectiveuseoftheengine'storque,andtokeeptheengineoperatingatanappropriatespeed.Thekeydiffe

7、rencebetweenamanualandanautomatictransmissionisthatthemanualtransmissionlocksandunlocksdifferentsetsofgearstotheoutputshafttoachievethevariousgearratios,whileinanautomatictransmission,thesamesetofgearsproducesallofthedifferentgearratios.Theplanetarygearsetisthedevicethatmakesthispossibleinanautomati

8、ctransmission.Let'stakealookathowtheplanetarygearsetworks.PlanetaryGearsets&GearRatiosWhenyoutakeapartandlookinsideanautomatictransmission,youfindahuge Aningeniousplanetarygearset Asetofbandstolockpartsofagearset Asetofthreewet-plateclutchestolockotherpartsofthegearset Anincrediblyoddhydraul

9、icsystemthatcontrolstheclutchesandbands AlargegearpumptomovetransmissionfluidaroundThecenterofattentionistheplanetarygearset.Aboutthesizeofacantaloupe,thisonepartcreatesallofthedifferentgearratiosthatthetransmissioncanproduce.Everythingelseinthetransmissionistheretohelptheplanetarygearsetdoitsthing.

10、ThisamazingpieceofgearinghasappearedonHowStuffWorksbefore.Youmayrecognizeitfromtheelectricscrewdriverarticle.Anautomatictransmissioncontainstwocompleteplanetarygearsetsfoldedtogetherintoonecomponent.SeeHowGearRatiosWorkforanintroductiontoplanetarygearsets.Fromlefttoright:theringgear,planetcarrier,an

11、dtwosungearsAnyplanetarygearsethasthreemaincomponents: Thesungear Theplanetgearsandtheplanetgears'carrier TheringgearEachofthesethreecomponentscanbetheinput,theoutputorcanbeheldstationary.Choosingwhichpieceplayswhichroledeterminesthegearratioforthegearset.Let'stakealookatasingleplanetarygear

12、set.Oneoftheplanetarygearsetsfromourtransmissionhasaringgearwith72teethandasungearwith30teeth.Wecangetlotsofdifferentgearratiosoutofthisgearset.InputOutputStationaryCalculationGearRatioASun(S)PlanetCarrier(C)Ring(R)1+R/S3.4:1BPlanetCarrier(C)Ring(R)Sun(S)1/(1+S/R)0.71:1CSun(S)Ring(R)PlanetCarrier(C)

13、-R/S-2.4:1Also,lockinganytwoofthethreecomponentstogetherwilllockupthewholedeviceata1:1gearreduction.Noticethatthefirstgearratiolistedaboveisareduction-theoutputspeedisslowerthantheinputspeed.Thesecondisanoverdrive-theoutputspeedisfasterthantheinputspeed.Thelastisareductionagain,buttheoutputdirection

14、isreversed.Thereareseveralotherratiosthatcanbegottenoutofthisplanetarygearset,butthesearetheonesthatarerelevanttoourautomatictransmission.Youcantrytheseoutintheanimationbelow:>InputOutputStsticmaryOsarRath|Suri(S)PldrielCarrier(C)Ring(R3,4;1lPlanetGarner(C)Ring(R)Sun(S)0.71.1HSun(£)Rjng(R)Pl

15、anetCarrier(C)-2.4:1鬥T倔Rii-rttWfrh?.AnimationofthedifferentgearratiosrelatedtoautomatictransmissionsClickonthebuttonsontheleftinthetableabove.Sothisonesetofgearscanproduceallofthesedifferentgearratioswithouthavingtoengageordisengageanyothergears.Withtwoofthesegearsetsinarow,wecangetthefourforwardgea

16、rsandonereversegearourtransmissionneeds.We'llputthetwosetsofgearstogetherinthenextsection.CompoundPlanetaryGearsetThisautomatictransmissionusesasetofgears,calledacompoundplanetarygearset,thatlookslikeasingleplanetarygearsetbutactuallybehavesliketwoplanetarygearsetscombined.Ithasoneringgearthatis

17、alwaystheoutputofthetransmission,butithastwosungearsandtwosetsofplanets.Let'slookatsomeoftheparts:爭245HHwShdlWcrikiHowthegearsinthetransmissionareputtogetherLefttoright:theringgear,planetcarrier,andtwosungearsThefigurebelowshowstheplanetsintheplanetcarrier.Noticehowtheplanetontherightsitslowerth

18、antheplanetontheleft.Theplanetontherightdoesnotengagetheringgear-itengagestheotherplanet.Onlytheplanetontheleftengagestheringgear.«How曲jdmw打瀆.ThispFanetengagestfieotherpEanetancFfsengagedbythesmalrsunPlanetcarrier:Notethetwosetsofplanets.Nextyoucanseetheinsideoftheplanetcarrier.Theshortergearsa

19、reengagedonlybythesmallersungear.Thelongerplanetsareengagedbythebiggersungearandbythesmallerplanets.ew&u刼碍iw口屆iThisplanetis-engaieclbythe-smallersungearInsidetheplanetcarrier:Notethetwosetsofplanets.AutomaticTransmissionGearsFirstGearInfirstgear,thesmallersungearisdrivenclockwisebytheturbineinth

20、etorqueconverter.Theplanetcarriertriestospincounterclockwise,butisheldstillbytheone-wayclutch(whichonlyallowsrotationintheclockwisedirection)andtheringgearturnstheoutput.Thesmallgearhas30teethandtheringgearhas72,sothegearratiois:Ratio=-R/S=-72/30=-2.4:1Sotherotationisnegative2.4:1,whichmeansthattheo

21、utputdirectionwouldbeoppositetheinputdirection.Buttheoutputdirectionisreallythesameastheinputdirection-thisiswherethetrickwiththetwosetsofplanetscomesin.Thefirstsetofplanetsengagesthesecondset,andthesecondsetturnstheringgear;thiscombinationreversesthedirection.Youcanseethatthiswouldalsocausethebigge

22、rsungeartospin;butbecausethatclutchisreleased,thebiggersungearisfreetospinintheoppositedirectionoftheturbine(counterclockwise).ThehifrlvrtohowisrranniinlrhroiHihTherranniision.SecondGearThistransmissiondoessomethingreallyneatinordertogettherationeededforsecondgear.Itactsliketwoplanetarygearsetsconne

23、ctedtoeachotherwithacommonplanetcarrier.Thefirststageoftheplanetcarrieractuallyusesthelargersungearastheringgear.Sothefirststageconsistsofthesun(thesmallersungear),theplanetcarrier,andthering(thelargersungear).Theinputisthesmallsungear;theringgear(largesungear)isheldstationarybytheband,andtheoutputi

24、stheplanetcarrier.Forthisstage,withthesunasinput,planetcarrierasoutput,andtheringgearfixed,theformulais:1+R/S=1+36/30=2.2:1Theplanetcarrierturns2.2timesforeachrotationofthesmallsungear.Atthesecondstage,theplanetcarrieractsastheinputforthesecondplanetarygearset,thelargersungear(whichisheldstationary)

25、actsasthesun,andtheringgearactsastheoutput,sothegearratiois:1/(1+S/R)=1/(1+36/72)=0.67:1Togettheoverallreductionforsecondgear,wemultiplythefirststagebythesecond,2.2x0.67,togeta1.47:1reduction.Thismaysoundwacky,butitworks.ThirdGearMostautomatictransmissionshavea1:1ratiointhirdgear.You'llrememberf

26、romtheprevioussectionthatallwehavetodotogeta1:1outputislocktogetheranytwoofthethreepartsoftheplanetarygear.Withthearrangementinthisgearsetitiseveneasier-allwehavetodoisengagetheclutchesthatlockeachofthesungearstotheturbine.Ifbothsungearsturninthesamedirection,theplanetgearslockupbecausetheycanonlysp

27、ininoppositedirections.Thislockstheringgeartotheplanetsandcauseseverythingtospinasaunit,producinga1:1ratio.OverdriveBydefinition,anoverdrivehasafasteroutputspeedthaninputspeed.It'saspeedincrease-theoppositeofareduction.Inthistransmission,engagingtheoverdriveaccomplishestwothingsatonce.IfyoureadH

28、owTorqueConvertersWork,youlearnedaboutlockuptorqueconverters.Inordertoimproveefficiency,somecarshaveamechanismthatlocksupthetorqueconvertersothattheoutputoftheenginegoesstraighttothetransmission.Inthistransmission,whenoverdriveisengaged,ashaftthatisattachedtothehousingofthetorqueconverter(whichisbol

29、tedtotheflywheeloftheengine)isconnectedbyclutchtotheplanetcarrier.Thesmallsungearfreewheels,andthelargersungearisheldbytheoverdriveband.Nothingisconnectedtotheturbine;theonlyinputcomesfromtheconverterhousing.Let'sgobacktoourchartagain,thistimewiththeplanetcarrierforinput,thesungearfixedandtherin

30、ggearforoutput.Ratio=1/(1+S/R)=1/(1+36/72)=0.67:1Sotheoutputspinsonceforeverytwo-thirdsofarotationoftheengine.Iftheengineisturningat2000rotationsperminute(RPM),theoutputspeedis3000RPM.Thisallowscarstodriveatfreewayspeedwhiletheenginespeedstaysniceandslow.ReverseReverseisverysimilartofirstgear,except

31、thatinsteadofthesmallsungearbeingdrivenbythetorqueconverterturbine,thebiggersungearisdriven,andthesmallonefreewheelsintheoppositedirection.Theplanetcarrierisheldbythereversebandtothehousing.So,accordingtoourequationsfromthelastpage,wehave:Ratio=-R/S=72/36=20:1Sotheratioinreverseisalittlelessthanfirs

32、tgearinthistransmission.GearRatiosThistransmissionhasfourforwardgearsandonereversegear.Let'ssummarizethegearratios,inputsandoutputs:GearInputOutputFixedGearRatio1st30-toothsun72-toothringPlanetcarrier2.4:12nd30-toothsunPlanetcarrier36-toothring2.2:1Planetcarrier72-toothring36-toothsun0.67:1Total

33、2nd1.47:13rd30-and36-toothsuns72-toothring1.0:1ODPlanetcarrier72-toothring36-toothsun0.67:1Reverse36-toothsun72-toothringPlanetcarrier-2.0:1Afterreadingthesesections,youareprobablywonderinghowthedifferentinputsgetconnectedanddisconnected.Thisisdonebyaseriesofclutchesandbandsinsidethetransmission.Int

34、henextsection,we'llseehowthesework.ClutchesandBandsinanAutomaticTransmissionInthelastsection,wediscussedhoweachofthegearratiosiscreatedbythetransmission.Forinstance,whenwediscussedoverdrive,wesaid:Inthistransmission,whenoverdriveisengaged,ashaftthatisattachedtothehousingofthetorqueconverter(whic

35、hisboltedtotheflywheeloftheengine)isconnectedbyclutchtotheplanetcarrier.Thesmallsungearfreewheels,andthelargersungearisheldbytheoverdriveband.Nothingisconnectedtotheturbine;theonlyinputcomesfromtheconverterhousing.Togetthetransmissionintooverdrive,lotsofthingshavetobeconnectedanddisconnectedbyclutch

36、esandbands.Theplanetcarriergetsconnectedtothetorqueconverterhousingbyaclutch.Thesmallsungetsdisconnectedfromtheturbinebyaclutchsothatitcanfreewheel.Thebigsungearisheldtothehousingbyabandsothatitcouldnotrotate.Eachgearshifttriggersaseriesofeventslikethese,withdifferentclutchesandbandsengaginganddisen

37、gaging.Let'stakealookataband.BandsInthistransmissiontherearetwobands.Thebandsinatransmissionare,literally,steelbandsthatwraparoundsectionsofthegeartrainandconnecttothehousing.Theyareactuatedbyhydrauliccylindersinsidethecaseofthetransmission.OneofthebandsInthefigureabove,youcanseeoneofthebandsint

38、hehousingofthetransmission.Thegeartrainisremoved.Themetalrodisconnectedtothepiston,whichactuatestheband.Thepistonsthatactuatethebandsarevisiblehere.Aboveyoucanseethetwopistonsthatactuatethebands.Hydraulicpressure,routedintothecylinderbyasetofvalves,causesthepistonstopushonthebands,lockingthatpartoft

39、hegeartraintothehousing.Theclutchesinthetransmissionarealittlemorecomplex.Inthistransmissiontherearefourclutches.Eachclutchisactuatedbypressurizedhydraulicfluidthatentersapistoninsidetheclutch.Springsmakesurethattheclutchreleaseswhenthepressureisreduced.Belowyoucanseethepistonandtheclutchdrum.Notice

40、therubbersealonthepiston-thisisoneofthecomponentsthatisreplacedwhenyourtransmissiongetsrebuilt.OneoftheclutchesinatransmissionThenextfigureshowsthealternatinglayersofclutchfrictionmaterialandsteelplates.Thefrictionmaterialissplinedontheinside,whereitlockstooneofthegears.Thesteelplateissplinedontheou

41、tside,whereitlockstotheclutchhousing.Theseclutchplatesarealsoreplacedwhenthetransmissionisrebuilt.TheclutchplatesThepressurefortheclutchesisfedthroughpassagewaysintheshafts.Thehydraulicsystemcontrolswhichclutchesandbandsareenergizedatanygivenmoment.FROM:自动变速器的工作原理耐斯卡瑞姆介绍自动变速器的工作原理如果你驾驶过带有自动变速器的汽车，那么

42、你一定知道手动变速器与自动变速器之间存在两个很大的区别：自动变速器中没有离合器踏板自动变速器中没有换档手柄，一旦让变速器传递动力，那么接下来的一切都是自动完成的了。虽然自动变速器（包括液力变矩器）与手动变速器（包括离合器）完成的功能是相同的，但它们却是以完全不同的方式来实现的。最终证实，自动变速器的工作方式令人惊异。自动变速器概图变速器的工作赢I本文是通过一个具体的自动变速器来阐述其中的原理，我们从整个系统的关键一一行星齿轮系入手，然后我们将看到自动变速器是如何组装在一起的，学习控制装置是如何工作的，讨论在自动变速器控制方面的一些复杂的关系。自动变速器和手动变速器一样，主要功能就是允许发动机工

43、作在小范围变速的速度内，变速器却能够输出较大变速范围的速度。r:.Mercedes-奔驰CLK,自动变速器，剖面立体图如果没有变速器，汽车将被限制在一种传动比，并且那个传动必须被选择作为汽车的最高期望速度。如果您想要以80英里/小时的最高速度行驶，则传动比类似于手动变速器汽车的第三档。您大概从未尝试仅使用第三档驾驶一辆手动变速的汽车。如果您尝试过，您马上会发现启动时几乎没有加速过程，而是直接以很高的速度启动,引擎是工作在警戒线附近的。这样汽车很快就会损害，而且几乎无法驾驶。因此变速器是利用齿轮来更有效地利用发动的扭矩的，并且使得发动机工作在适当的速度。手动和自动变速器之间的关键性区别在于：手动

44、变速器采用锁止或打开不同的齿轮，从而使输出轴获得不同传动比，而在自动变速器中，同样是这些齿轮，但是能得到一定范围内所有的不同的传动比。而行星齿轮系是使此成为可能的装置。让我们来看一下行星齿轮系是如何工作的。行星齿轮系和齿轮传动比当您拆散自动变速器往里面观察，可以发现，在一个相对狭小的空间里布满了很多零件。在这些零件中有：一个精巧的行星齿轮系一套锁止齿轮的钢带三个锁住另外一些齿轮的湿式片式离合器控制离合器和钢带的复杂液压系统为变速器提供液压的齿轮泵关注的重点是行星齿轮系。变速器所产生的所有不同的传动比决定于齿轮系尺寸的大小。变速器里其他的零部件是协助行星轮系产生不同传动比的。这套装置曾经出现在材

45、料的工作方式中。您可以从电螺丝刀中找到。一个自动变速器中包含有由两套行星齿轮系组合在一起而成的一个部件。其介绍可以参见齿轮系工作方式。从左到右：内齿圈，行星架，和两个太阳轮行星齿轮系有三个主要的组成部分：太阳轮行星轮和行星架内齿圈这三个组成中的任何一组成都可以作为输入或输出，或者被固定。哪些组成充当何种角色取决于行星齿轮系的速度比。下面的动画可以显示出其中的关系。JInputOutputStationaryGesirRstkiiSun(S)PlanetCarrier(C)Ring(ft)3,4;1OPlanetCarrier(C)向Sun(S)0.71'lSun电)Rmg(R)Plan

46、etCarrier(C)-2.4:1单击左边的在钮这是变速器中其中的一个行星齿轮系，内齿圈齿数为72,太阳轮齿数为30。我们可以从中的到很多不同的速比。输入输出固定计算齿轮速比A太阳轮(s)行星架(C)内齿圈(R)1+R/S3.4:1b行星架(C)内齿圈(R)太阳轮(s)1/(1+S/R)0.71:1C太阳轮(s)内齿圈(R)行星架(0-R/S-2.4:1并且，锁住三个组成中的任何两个组成将锁止整个个行星系，而此时速比为1：1。从表中可以看出，第一个中方案的速比为减速输出速度小于输入。第二种方案为加速输出速度高于输入。最后一种方案也是减速，但输出速度的方向相反。这个行星齿轮系还可以得到其他很多

47、的速比，而刚才的这些速比仅和我们的自动变速器有关。因此这一套行星齿轮系可以产生所有需要的不同的齿轮传动比，却不需要接合或不接合其他齿轮。把两套行星齿轮系置于一行，我们可以得到四个前进档和一个后退档。下一部分内容我们将这两个齿轮系组装在一起。复合行星齿轮系自动变速器中使用了一系列的行星齿轮系，我们称之为复合行星齿轮系，看起来好像只有一个简单的行星齿轮系，实际上却实现这两套齿轮系的功能。其中包含一个总是作为输出的内齿圈、两个太阳和两套行星装置。让我们看其中的一些零件：爭汕血HewMkT*WctMig变速器中的齿轮的组装从左到右：内齿圈，行星架，和两个太阳轮下图中，行星轮装在行星架上，可以看到，右边

48、的行星轮低于左边的行星轮。右边的行星轮不与内齿圈啮合一一它和另一个行星轮啮合。而只有左边的行星轮与内齿圈啮合。此行星轮与内齿圈啮合，由大太阳轮紫歸轮爲疔星7行星架：两个行星轮在下个图中，您可看到在行星架的内部，短行星轮与小太阳轮啮合,长行星轮同时与大太阳轮和小太阳轮啮合。行星架内部：两个行星轮自动变速档位第一档在一档，小太阳轮在变矩器的涡轮驱动下顺时针旋转。行星架将自动做逆时针转动，但是被离合器阻止了（离合器只允许单向旋转），从而内齿圈变成了输出。小太阳轮有30齿，内齿圈72齿，则速比为：Ratio=-R/S=-72/30=-2.4:1因此旋转速率为负的2.4:1,这意味着输出方向同输入的方向

49、是相反的。但事实上，输出方向是与输入方向相同的，这就是要引入两套行星齿轮系的原因。第一套与第二套啮合，而第二套输出至内齿圈，这样的组合把方向转回原先输入的方向。这样还是使得大太阳轮自转，而这时的离合器是不作用的，大太阳轮以同涡轮相反的方向（逆时针）自转。第二档变速器做一些单独的事情来获得二档所需的传动比。它像相互连接的两套行星轮和共同的行星架相连接。行星架的第一级事实上是把大太阳轮用作内齿圈。所以第一级包括太阳轮（小太阳轮）、行星架和“内齿圈”（大太阳轮）。输入是小太阳轮，内齿圈（大太阳轮）由钢带保持静止，输出是行星架。对于一级，太阳轮作为输入，行星架作为输出，而内齿圈固定，其公式为：1+R/S=1+36/30=22:1小太阳轮旋转一圈，行星架则转过2.2圈。在第二级，行星架作为第二套行星齿轮系的输入，大太阳轮（被固定）作为太阳轮，而内齿圈则作为输出，其齿轮速比为：1/（1+S/R）=1/（1+36/72）=0.67:1要得到二档的减速比，我们把第一级减速比和第二级减速比相乘，2.2x0.67，得到1.47:1。这也许听起来有些怪，但却是这么运作的。第三档