《汽車專業(yè)英語》課件第3章

3.1Gears3.2ClutchPacks3.3AutomaticTransmission3.4SteeringGear3.5Brakes3.6Four-Wheel-Drive3.7DifferentialPARTⅢCHASSISPART?ⅢCHASSIS學習目標通過本章的學習，你應當能夠：掌握與汽車底盤有關的專業(yè)術語、專業(yè)詞匯和縮略語。掌握汽車底盤英語的習慣表達方法。能查閱汽車底盤的有關英文資料。能借助字典翻譯汽車底盤方面的文章。3.1Gears

Gearsareusedtotransmitpowerbetweenshaftsrotatingusuallyatdifferentspeeds.Gearsdoseveralimportantjobs,butmostimportant,theyprovideagearreductioninmotorizedequipment.Thisiskeybecause,often,asmallmotorspinningveryfastcanprovideenoughpowerforadevice,butnotenoughtorque.Withagearreduction,theoutputspeedcanbereducedwhilethetorqueisincreased.

Anotherthinggearsdoisadjustthedirectionofrotation.Forinstance,thedifferentialofcarhastoturnpower90degreestoapplyittothewheels.

Theratioisdeterminedbythedistancesfromthecenterofthegeartothepointofcontact.Forinstance,inadevicewithtwogears,ifonegearistwicethesizeoftheother,theratiowouldbe2:1.

Theproblemwiththistypeofgearisthatthedistancefromthecenterofeachgeartothepointofcontactchangesasthegearsrotate.Thismeansthatthegearratiochangesasthegearturns,meaningthattheoutputspeedalsochanges.Ifyouusedagearlikethisinyourcar,itwouldbeimpossibletomaintainaconstantspeed－youwouldbeacceleratinganddeceleratingconstantly.

Manymoderngearsuseaspecialtoothprofilecalledaninvolute.Thisprofilehastheveryimportantpropertyofmaintainingaconstantspeedratiobetweenthetwogears.Someofthemanytypesofgearsareillustratedbelow：

SpurGears(SeeFig.3.1.1)

Apairofspurgearsformountingonparallelshaftsarethemostcommontypeofgears，whichhavestraightteeth.Sometimes,manyspurgearsareusedatoncetocreateverylargegearreductions.

Thespurgearcanbereallyloud.Eachtimeageartoothengagesatoothontheothergear,theteethcollide,andthisimpactmakesanoise.Italsoincreasesthestressonthegearteeth.

Toreducethenoiseandstressinthegears,mostofthegearsinyourcararehelical.Fig.3.1.1Spurgears

HelicalGears(SeeFig.3.1.2)

Likespurgears

helicalgearsconnectparallelshafts,howevertheteetharenotparalleltotheshaftaxesbutliealonghelicesabouttheaxes.Fig.3.1.2

Helicalgears

Whentwoteethonahelicalgearsystemengage,thecontactstartsatoneendofthetoothandgraduallyspreadsasthegearsrotate,untilthetwoteethareinfullengagement.

Thisgradualengagementmakeshelicalgearsoperatemuchmoresmoothlyandquietlythanspurgears.Forthisreason,helicalgearsareusedinalmostallcartransmissions.Becauseoftheangleoftheteethonhelicalgears,theycreateathrustloadonthegearwhentheymesh.Devicesthatusehelicalgearshavebearingsthatcansupportthisthrustload.Fig.3.1.3Bevelgears

BevelGears(SeeFig.3.1.3)

Bevelgearsareusefulwhenthedirectionofashaft’srotationneedstobechanged.Theyareusuallymountedonshaftsthatare90degreesapart,butcanbedesignedtoworkatotheranglesaswell.

Theteethonbevelgearscanbestraight,spiralorhypoid.Straightbevelgearteethactuallyhavethesameproblemasstraightspurgearteeth－aseachtoothengages,itimpactsthecorrespondingtoothallatonce.

Justlikewithspurgears,thesolutiontothisproblemistocurvethegearteeth.Thesespiralteethengagejustlikehelicalteeth:thecontactstartsatoneendofthegearandprogressivelyspreadsacrossthewholetooth.Fig.3.1.4

Wormgears

Justlikewithspurgears,thesolutiontothisproblemistocurvethegearteeth.Thesespiralteethengagejustlikehelicalteeth:thecontactstartsatoneendofthegearandprogressivelyspreadsacrossthewholetooth.

Theteethonbevelgearscanbestraight,spiralorhypoid.Straightbevelgearteethactuallyhavethesameproblemasstraightspurgearteeth－aseachtoothengages,itimpactsthecorrespondingtoothallatonce.

WormGears(SeeFig.3.1.4)

Fig.3.1.4WormgearsAwormandwormwheelgivesalargespeedratiobutwithsignificantsliding.Itiscommonforwormgearstohavereductionsof20:1,andevenupto300:1orgreater.

Manywormgearshaveaninterestingpropertythatnoothergearsethas:thewormcaneasilyturnthegear,butthegearcannotturntheworm.Thisisbecausetheangleonthewormissoshallowthatwhenthegeartriestospinit,thefrictionbetweenthegearandthewormholdstheworminplace.Asinglepairmaybeinadequateforcertainsourcesandloads,inwhichcasemorecomplexcombinationssuchasthegearbox,knownasgeartrains,arenecessary.TechnicalWords

gear n. 齒輪

reduction n. 減少

torque n. 力矩，轉矩

differential n. 差速器

shaft n. 軸

involute n. 漸開線

spur n. 直齒

parallel

n.；adj. 平行線；平行的

collide

v. 碰撞

helical

n.；adj. 螺旋線；螺旋線的

angle

n. 角度

engagement n. 嚙合

thrust

n. 推力

mesh v. 嚙合

bevel n.；adj. 錐體；錐形的

spiral adj. 螺旋，螺旋的

hypoid n 準雙曲面

worm n. 蝸桿

friction n. 摩擦力PhrasesandExpressions

spurgears 直齒輪

helicalgears 斜齒輪

bevelgears 錐齒輪

wormgears 蝸輪蝸桿

hold…inplace 卡住，咬死NotesontheText

1．Theydoseveralimportantjobs,butmostimportant,theyprovideagearreductioninmotorizedequipment.齒輪有很多作用，但最重要的作用是動力設備的減速。

2．Eachtimeageartoothengagesatoothontheothergear,theteethcollide,andthisimpactmakesanoise.Italsoincreasesthestressonthegearteeth.每當一個齒輪的齒與另一齒輪嚙合時，輪齒間就發(fā)生碰撞，這種碰撞就發(fā)出了噪音，同時也增加了齒面上的壓應力。

3.Thisgradualengagementmakeshelicalgearsoperatemuchmoresmoothlyandquietlythanspurgears.逐步嚙合使斜齒輪在運轉時，比直齒輪更平滑、噪音更低。

4.Theteethonbevelgearscanbestraight,spiralorhypoid.Straightbevelgearteethactuallyhavethesameproblemasstraightspurgearteeth－aseachtoothengages,itimpactsthecorrespondingtoothallatonce.錐齒輪的齒形可以是直齒、螺旋形或準雙曲面。直齒錐齒輪和直齒輪存在著同樣的問題-——即嚙合時始終存在齒間碰撞。

5．Manywormgearshaveaninterestingpropertythatnoothergearsethas:thewormcaneasilyturnthegear,butthegearcannotturntheworm.很多蝸輪蝸桿具有其他齒輪傳動所沒有的一種有趣的性質：蝸桿能很容易地帶動蝸輪，但是蝸輪卻帶不動蝸桿。Exercises

Ⅰ.?AnswerthefollowingquestionsinEnglish.

1．Whatdeterminestheratioonanygears?

2．Whycanthespurgearmakeanoisewhenworking?

3．Whydospurgearscreateathrustloadonthegearwhentheymesh?

4．Howdowechangethedirectionofashaft’srotation?

5．Whatisthereasonwhycanthewormeasilyturnthegear,butthegearcannotturntheworm?

Ⅱ.?TranslatefollowingexpressionsintoEnglish.

1．齒輪中心到兩齒的嚙合點的距離

2．旋轉運動的傳遞方向

3．維持穩(wěn)定的傳動比

4．降低速度而增加力矩

5．完全嚙合

6．斜齒輪螺旋角

7．使輪齒變?yōu)榍€

8．蝸輪蝸桿間的摩擦力Ⅲ.?TranslatefollowingsentencesintoEnglish.

1．在后輪的差速器中，動力傳到中間后，差速器必須將其轉90度傳給車輪。

2．齒輪減速可以降低速度同時增加力矩。

3．很多現(xiàn)代齒輪使用斷面為漸開線的齒廓。

4．為了降低噪音，我們的大多數(shù)轎車使用斜齒輪。

5．錐齒輪的齒可以是直齒、螺旋或準雙曲面。

6．斜齒輪的齒有個角度，在嚙合時就會產生軸向推力。所以斜齒輪傳動機構均使用止推軸承。

7．螺旋錐齒輪的嚙合和斜齒輪是一樣的：齒的接觸從齒間的點接觸開始然后逐步過渡到全齒接觸。

8．當需要很大的降速比時，可以使用蝸輪蝸桿。通常蝸輪蝸桿的減速比可達到20∶1，甚至可以達到300∶1或更大。

Ⅳ.?Studythefollowinglistandname.*

gearbox—gearing:firstspeeddrivinggear,firstspeeddrivengear,reversedrivinggear,reversedrivengear,reverseidlergear,first-and-secondspeedsynchronizer,third-and-fourthspeedsynchronizer,neutralgear.

gearbox—gear-shiftmechanism:gearselectorfork,shifterfork,forkrod,selectorshaft,selectorinnerlever,selectorouterlever,speedchangeleverknob,angularlever,shiftbar,forklever,flatlever.

ReadingMaterialGearbox

Thefive-speedmanualtransmission(SeeFig.3.1.5)isfairlystandardoncarstoday.Itlookssomethinglikethisinternally:Therearethreeforkscontrolledbythreerodsthatareengagedbytheshiftlever.Lookingattheshiftrodsfromthetop,theylooklikethis(SeeFig.3.1.6)inneutral,reverse,firstandsecondgear:Fig.3.1.5Thefive-speedmanualtransmissionFig.3.1.6Thefive-speedmanualtransmission

The?“H”?patternallowsyoutomovetheshiftrodbetweenthecontrolrodsforthethreeforksandmovetherodsbackandforth.

Asequentialmanualtransmissionworksthesameway.Thereisstillasetofgearselectorforksthatmovecollarsthatengagegears.Theonlydifferenceisthewaythecontrolrodsaremanipulated.The?“H”?patterniseliminatedandreplacedwithadifferentmotion.

Inaracecar,themotionoftheshiftleveriseither?“pushforward”toup-shiftor“pullbackward”todownshift.Ifyouareinagearandyouwanttogotoahighergear(e.g.from2ndto3rd),youpushtheshiftleverforward.Togofrom3rdto4th,youpushtheleverforwardagain.Togofrom4thto5th,youpressitforwardagain.Itisthesamemotioneverytime.

Todropbackdownagear,sayfrom5thto4th,youpulltheleverbackward.(YoucanseeseveralvideosshowingtheshiftlevermotionontheSEQSHIFTvideopage).Onamotorcycle,youdothesamething,butinsteadofmovingaleverbackandforthwithyourhand,youmovealeverupanddownwithyourfoot.

Whatthesemotionsaredoingisrotatingaratchetingdrum.ThedrumlookslikeFig.3.1.7.Fig.3.1.7Thedrum

Youcanseethattherearegroovescutintothedrum.Thesegroovescandooneoftwothings:●?Ifthedrumislocatedawayfromthetransmission’sgears,thegroovescontrolstandardcontrolrods.●?Ifthedrumislocatednexttothegears,thegroovesdirectlymovethegearselectorfork,andnocontrolrodsareneeded.Thisseemstobethemorecommontechniquebecauseithasfewerpartsandismorecompact.

So,whenyoumovethelever,itrotatesthedrumoneincrement(forexample,50degrees).Thisrotationcausestherodsorforkstomoveaccordingtothegroovesinthedrum,changingthegears.

Becauseofthedrum,youhavetoshiftinsequence.Thereisnoskipping,forexample,fromfirstgeartothird.Youmustalwaysgothroughsecondgeartogettothirdgear.Itisthesamewhendownshifting.Theadvantageofthissystemisthatshiftingmistakesareimpossible.Youalwaysgotothenextgear.TechnicalWords

gearbox 變速箱，變速器

five-speedtransmission 五擋變速器，五速齒輪箱

shiftlever 變速桿

neutralgear 空擋

reversegear 倒擋

firstandsecondgear 一、二擋3.2

ClutchPacks

Aclutchisasubcomponentofanengine’stransmissiondesignedtoallowengagementordisengagementoftheenginetowhateverapparatusisbeingdriven.Aclutchmayalsobeadeviceonashaftthatwill?“slip”?whenhigherthannormalresistanceisencountered.

Therearemanydifferentclutchdesigns,butmostarebasedononeormorefrictiondiscs,pressedtightlytogetheroragainstaflywheelusingsprings.Thespringpressureisreleasedwhentheclutchpedalisdepressedandthediscsareheldlesstightlyandallowedtorotatefreely.

Clutchesareusefulindeviceswithtworotatingshafts.Inthesedevices,oneoftheshaftsistypicallydrivenbyamotororpulley,andtheothershaftisdrivinganotherdevice.Theclutchconnectsthetwoshaftssothattheycaneitherbelockedtogetherandspinatthesamespeed,orbedecoupledandspinatdifferentspeeds.

Inacar,theenginespinsallthetimeandthecarwheelsdon’t.Inorderforacartostopwithoutkillingtheengine,thewheelsneedtobedisconnectedfromtheenginesomehow.Theclutchsmoothlyengageaspinningenginetoanon-spinningtransmissionbycontrollingtheslippagebetweenthem.

IntheFig.3.2.1,theflywheelisconnectedtotheengine,andtheclutchplateisconnectedtothetransmission.Fig.3.2.1Diaphragmspringclutch

Whenyourfootisoffthepedal,thespringswillpushthepressureplateagainsttheclutchdisc,whichinturnpressesagainsttheflywheel.Thislockstheenginetothetransmissioninputshaft,causingthemtospinatthesamespeed.

Theamountofforcetheclutchcanholddependsonthefrictionbetweentheclutchplateandtheflywheel,andhowmuchforcethespringputsonthepressureplate.Thefrictionforceintheclutchworksjustliketheblocksinthefrictionsectionofbrake,exceptthatthespringpressesontheclutchplateinsteadofweightpressingtheblockintotheground.

Whentheclutchpedalispressed,acableorhydraulicpistonpushesonthereleasefork,whichpressesthethrow-outbearingagainstthemiddleofthediaphragmspring.Asthemiddleofthediaphragmspringispushedin,aseriesofpinsneartheoutsideofthespringcausesthespringtopullthepressureplateawayfromtheclutchdisc.Thisreleasestheclutchfromthespinningengine.

Notethespringsintheclutchplate.Thesespringshelptoisolatethetransmissionfromtheshockoftheclutchengaging.Themostcommonproblemwithclutchesisthatthefrictionmaterialonthediscwearsout.Thefrictionmaterialonaclutchdiscisverysimilartothefrictionmaterialonthepadsofadiscbrake,ortheshoesofadrumbrake－afterawhile,itwearsaway.

Whenmostorallofthefrictionmaterialisgone,theclutchwillstarttoslip,andeventuallyitwon’ttransmitanypowerfromtheenginetothewheels.

Theclutchonlywearswhiletheclutchdiscandtheflywheelarespinningatdifferentspeeds.Whentheyarelockedtogether,thefrictionmaterialisheldtightlyagainsttheflywheel,andtheyspininsync.Itisonlywhentheclutchdiscisslippingagainsttheflywheelthatwearingoccurs.Soifyouarethetypeofdriverwhoslipstheclutchalot,youwillwearoutyourclutchalotfaster.

Inacaritisoperatedbytheleft-mostpedal.Nopressureonthepedalmeansthattheclutchplatesareengaged(driving),whiledepressingthepedalwilldisengagetheclutchplates,allowingthedrivertoshiftgears.Whentheright-mostpedal(theaccelerator)ispressedwhiletheclutchpedalisbeingletout.

Carsequippedwithautomatictransmissionsnormallydonothaveaclutch.Onthese,thetransmissionoperatesautomaticalysothatthedriverisnotrequiredtouseaclutchtoshiftgears.TechnicalWords

clutch n. 離合器

transmission n. 變速器

cordless adj. 充電式的

chainsaw n. 鏈鋸

centrifugal adj. 離心力的

pulley n. 皮帶輪

chuck n.&v. (鉆)夾

engage v. 接合，嚙合

slippage n. 打滑

flywheel n. 飛輪

friction n. 摩擦系數(shù)，摩擦

cable n. 繩索

diaphragm n. 膜片

isolate v. 隔離PhrasesandExpressions

manualtransmission 手動變速器

automatictransmission 自動變速器

clutchplate 離合器盤

pressureplate 壓盤

hydraulicpiston 液壓活塞

throw-outbearing 分離軸承

diaphragmspring 膜片彈簧NotesontheText

1.?Inorderforacartostopwithoutkillingtheengine,thewheelsneedtobedisconnectedfromtheenginesomehow.為了在發(fā)動機不熄火的情況下使汽車停下來，車輪需要斷開與發(fā)動機的聯(lián)系。

2.?Whenyourfootisoffthepedal,thespringspushthepressureplateagainsttheclutchdisc,whichinturnpressesagainsttheflywheel.Thislockstheenginetothetransmissioninputshaft,causingthemtospinatthesamespeed.當你松開踏板，膜片彈簧將壓盤逐漸壓緊在離合器盤上，壓力依次傳到飛輪。這樣使發(fā)動機和傳動系輸入軸可靠地接合，使它們以相同的轉速運轉。

3.?Theamountofforcetheclutchcanholddependsonthefrictionbetweentheclutchplateandtheflywheel,andhowmuchforcethespringputsonthepressureplate.離合器能傳遞的力的大小取決于離合器盤和飛輪之間的摩擦系數(shù)，以及彈簧對壓盤的壓緊力的大小。

4.?Itisonlywhentheclutchdiscisslippingagainsttheflywheelthatwearingoccurs.Soifyouarethetypeofdriverwhoslipstheclutchalot,youwillwearoutyourclutchalotfaster.只有當離合器盤在飛輪上打滑時，才會出現(xiàn)磨損現(xiàn)象。因此，假如在你開車時，離合器常常打滑，那么，你的離合器就會迅速磨損。Exercises

Ⅰ.?AnswerthefollowingquestionsinEnglish.

1．Whydoyouneedaclutch?

2．Howdoestheclutchinyourcarwork?

3．Whatistheflywheelconnectedto?

4．Whatistheclutchplatelconnectedto?

5．Whatisthemostcommonproblemwithclutches?

Ⅱ.?TranslatefollowingexpressionsintoEnglish.

1．兩軸之間的聯(lián)結

2．兩軸分離

3．發(fā)動機與傳動系平穩(wěn)接合

4．以相同的轉速運轉

5．傳動系統(tǒng)的輸入軸

Ⅲ.?TranslatefollowingsentencesintoEnglish.

1．踩下踏板，離合器使發(fā)動機與傳動系統(tǒng)徹底分離。

2．松開踏板，離合器使發(fā)動機和傳動系輸入軸平穩(wěn)接合。

3．當離合器磨損后，就會打滑，最終，這個離合器將失去從發(fā)動機向車輪傳遞動力的能力。

4．假如你在開車時，常踏離合器，那么，你的離合器就會迅速磨損。

Ⅳ.?Readthefollowingtext,makingsureyouunderstandthemeaningof“clutch”.

clutch

v.?clutched,clutch·ing,clutch·es

v.

tr.

Tograspandholdtightly.

Toseize;snatch.

v.?

intr.

1．Toattempttograsporseize:clutchataliferaft.

2．Toengageordisengageamotorvehicle’sclutch.

3．Tofailinacriticalsituation,especiallyoutofnervousnessorfear.

n.

Ahand,claw,talon,orpawintheactofgrasping.

Atightgrasp.

Controlorpower.Oftenusedintheplural:caughtinthe

clutchesofsin.

Adeviceforgrippingandholding.

Anyofvariousdevicesforengaginganddisengagingtwoworkingpartsofashaftorofashaftandadrivingmechanism.

Theapparatus,suchasaleverorpedal,thatactivatesoneofthesedevices.

Atense,criticalsituation:camethroughintheclutch.

Aclutchbag.

ReadingMaterial

OtherClutchesinYourGarage

Therearemanyothertypesofclutchesinyourcarorinyourgarage:●?Anautomatictransmissioncontainsseveralclutches.Theseareusedtoengageanddisengagevarioussetsofplanetarygears.●?Anairconditioningcompressorinacarhasamagneticclutch.Thisallowsthecompressortoshutoffevenwhiletheengineisrunning.Whencurrentflowsthroughamagneticcoilintheclutch,theclutchengages.Assoonasthecurrentstops,suchaswhenyouturnoffyourairconditioning,theclutchdisengages.●?Mostcarsthathaveanengine-drivencoolingfanhaveathermostaticallycontrolledviscousclutch.Thisclutchispositionedatthehubofthefan,intheairflowcomingthroughtheradiator.Thistypeofclutchisaspecialviscousclutch,muchliketheviscouscouplingsometimesfoundinall-wheeldrivecars.Thefluidintheclutchgetsthickerasitheatsup,causingthefantospinfastertocatchupwiththeenginerotation.Whenthecariscold,thefluidintheclutchremainscoldandthefanspinsslowly,allowingtheenginetoquicklywarmuptoitsproperoperatingtemperature.●?Manycarshavelimitedslipdifferentialsorviscouscouplings,bothofwhichuseclutchestohelpincreasetraction.●?Agas-poweredchainsawandweedwackerhavecentrifugalclutches,sothatthechainsorstringscanstopspinningwithoutyouhavingtoturnofftheengine.3.3AutomaticTransmission

Boththeautomatictransmissionandthemanualtransmissionaccomplishexactlythesamething,andareidenticalineveryrespect,exceptthattheydoitintotallydifferentways.

Justlikethatofamanualtransmission,theautomatictransmission’sprimaryjobistoallowtheenginetooperateinitsnarrowrangeofspeedswhileprovidingawiderangeofoutputspeedstodrivethecar,whetheritisforwardsorbackwards.

Themaincomponentsthatmakeupanautomatictransmissionincludes:①PlanetaryGearSets,whicharethemechanicalsystemsthatprovidethevarious,forwardgearratiosaswellasreverse.②TheHydraulicSystem,whichcontrolstheClutchesandtheBandsinordertocontroltheplanetarygear,sets.③Seals,whichareusedtokeeptheoilwhereitissupposedtobeandpreventitfromleakingout.④TheTorqueConverter,whichactslikeaclutchtoallowthevehicletocometo,astopingearwhiletheengineisstillrunning.

Followingistheimportantpartofautomatictransmission:

Planetarygearsets(SeeFig.3.3.1).

Automatictransmissionscontainmanygearsinvariouscombinations.Inamanualtransmission,gearsslidealongshaftsasyoumovetheshiftleverfromonepositiontoanother,engagingvarioussizedgearsasrequiredinordertoprovidethecorrectgearratio.Inanautomatictransmission,however,thegearsareneverphysicallymovedandarealwaysengagedtothesamegears.Thisisaccomplishedthroughtheuseofplanetarygearsets.Fig.3.3.1Planetarygearset

Thebasicplanetarygearsetconsistsofasungear,aringgearandtwoormoreplanetgears,allremaininginconstantmesh.Theplanetgearsareconnectedtoeachotherthroughacommoncarrier,whichallowsthegearstospinonshaftscalled“pinions”whichareattachedtothecarrier.Theplanetarygearsystemgetsitsnamefromthefactthatthepinionsrevolvearoundthesungearandrotateatthesametime,justastheplanetsinoursolarsystemrotateandrevolvearoundthesun.

Oneexampleofawaythatthissystemcanbeusedisbyconnectingtheringgeartotheinputshaftcomingfromtheengine,connectingtheplanetcarriertotheoutputshaft,andlockingthesungearsothatitcan'tmove.Inthisscenario,whenweturntheringgear,theplanetswill“walk”alongthesungear(whichisheldstationary)causingtheplanetcarriertoturntheoutputshaftinthesamedirectionastheinputshaftbutataslowerspeedcausinggearreduction(similartoacarinfirstgear).

Ifweunlockthesungearandlockanytwoelementstogether,thiswillcauseallthreeelementstoturnatthesamespeedsothattheoutputshaftwillturnatthesamerateofspeedastheinputshaft.Thisislikeacarthatisinthirdorhighgear.

AnotherwaythatwecanuseaPlanetarygearsetisbylockingtheplanetcarrierfrommoving,thenapplyingpowertotheringgearwhichwillcausethesungeartoturnintheoppositedirectiongivingusreversegear.

Fig.3.3.2showshowthesimplesystemdescribedabovewouldlookinanactualtransmission.Theinputshaftisconnectedtotheringgear(Blue);TheOutputshaftisconnectedtotheplanetcarrier(Green)whichisalsoconnectedtoa“Multi-disk”clutchpack.Thesungearisconnectedtoadrum(yellow)whichisalsoconnectedtotheotherhalfoftheclutchpack.Surroundingtheoutsideofthedrumisaband(red)thatcanbetightenedaroundthedrumwhenrequiredtopreventthedrumwiththeattachedsungearfromturning.Fig.3.3.2Planetarygearsetsideview

Theclutchpackisused,inthisinstance,tolocktheplanetcarrierwiththesungearforcingbothtoturnatthesamespeed.Ifboththeclutchpackandthebandwerereleased,thesystemwouldbeinneutral.Turningtheinputshaftwouldturntheplanetgearsagainstthesungear,butsincenothingisholdingthesungear,itwilljustspinfreeandhavenoeffectontheoutputshaft.Toplacetheunitinfirstgear,thebandisappliedtoholdthesungearfrommoving.Toshiftfromfirsttohighgear,thebandisreleasedandtheclutchisappliedcausingtheoutputshafttoturnatthesamespeedastheinputshaft.

Manymorecombinationsarepossibleusingtwoormoreplanetarysetsconnectedinvariouswaystoprovidethedifferentforwardspeedsandreversethatarefoundinmodernautomatictransmissions.

Someoftheclevergeararrangementsfoundinfourandnow,five-speedautomaticsarecomplexenoughtomakeatechnicallyastutelayperson’sheadspintryingtounderstandtheflowofpowerthroughthetransmissionasitshiftsfromfirstgearthroughtopgearasthevehicleacceleratestohighwayspeed.Onnewervehicles,thevehicle’scomputermonitorsandcontrolstheseshiftssothattheyarealmostimperceptible.TechnicalWords

mechanical adj. 機械的

hydraulic adj. 液壓的，液體的

visualize v. 使具體化，使具形象，想象

band n. 帶

planetary adj. 行星的

governor n. 調速器，限速器

modulator n. 調制器，調節(jié)器

solenoid n. 電磁鐵

appropriate adj. 合適的，適當?shù)?/p>

mesh n. 嚙合，接合

carrier n. 行星齒輪架，承重構件

pinion n. 小齒輪，行星齒輪

scenario n. 順序

reverse n. 倒擋

astute adj. 精明的，機敏的

accelerate v. 使……加快，加速

imperceptible adj. 感覺不到的PhrasesandExpressions

consistof 由……組成

asymphonyof

……的混合

makeup 組成

planetarygear 行星齒輪

hydraulicsystem 液壓系統(tǒng)

sealsandgaskets 密封與襯墊

torqueconverter 液力變矩器

leakout 泄漏

gearratio 齒輪比

atthesamerateofspeed 以同樣的速率NotesontheText

1．Inamanualtransmission,gearsslidealongshaftsasyoumovetheshiftleverfromonepositiontoanother,engagingvarioussizedgearsasrequiredinordertoprovidethecorrectgearratio.在一個手動變速器里，當你操縱換擋桿從一個擋位換到另一個擋位時，齒輪沿軸向滑動，使大小不同的齒輪進行嚙合，從而滿足不同傳動比的需要。

2．Ifweunlockthesungearandlockanytwoelementstogether,thiswillcauseallthreeelementstoturnatthesamespeedsothattheoutputshaftwillturnatthesamerateofspeedastheinputshaft.如果我們松開太陽輪，把任意兩個構件連為一體，則三個構件就全部以同樣轉速運轉，那么輸出軸與輸入軸就會以相同的轉速運轉。

3．Manymorecombinationsarepossibleusingtwoormoreplanetarysetsconnectedinvariouswaystoprovidethedifferentforwardspeedsandreversethatarefoundinmodernautomatictransmissions.兩排或三排以上的簡單行星齒輪機構進行不同的組合，就形成了現(xiàn)代變速器各個前進擋和倒擋。

4．Onnewervehicles,thevehide’scomputermonitorsandcontrolstheseshiftssothattheyarealmostimperceptible.在較新型的汽車上，車上的計算機監(jiān)控這些擋位，使換擋操作幾乎感覺不到。Exercises

Ⅰ.?AnswerthefollowingquestionsinEnglish.

1．Whatdothemaincomponentsthatmakeupanautomatictransmissioninclude?

2．Whatareplanetarygearsetsdesignedtodo?

3．Inanautomatictransmission,howdoesitprovidethecorrectgearratio?

4．Whatdoesthebasicplanetarygearsetconsistof?

5．Howwilltheoutputshaftturnatthesamerateofspeedastheinputshaft?

Ⅱ.?TranslatefollowingexpressionsintoEnglish.

1．行星齒輪系統(tǒng)

2．保持油位防止泄漏

3．手動變速器和自動變速器的差別

4．從頭擋到高速擋

5．五擋自動變速器

6．輸出軸

Ⅲ.?TranslatefollowingsentencesintoEnglish.

1．液力變矩器像離合器一樣，允許發(fā)動機在運轉時換擋停車。

2．密封和襯墊可以防止泄漏。

3．在自動變速器中，無須通過操縱變速桿換擋。

4．行星齒輪組是提供各擋速比和倒擋的機械結構。

5．輸出軸與行星齒輪架連接。

6．在新型汽車中，計算機監(jiān)控換擋。ReadingMaterialAVerySimpleTwo-SpeedTransmission

Tounderstandthebasicideabehindastandardtransmission,Fig.3.3.3showsaverysimpletwo-speedtransmissioninneutral:

Let’slookateachofthepartsinFig.3.3.3tounderstandhowtheyfittogether:●?Thegreenshaftcomesfromtheenginethroughtheclutch.Thegreenshaftandgreengearareconnectedasasingleunit.(Theclutchisadevicethatletsyouconnectanddisconnecttheengineandthetransmission.Whenyoupushintheclutchpedal,theengineandthetransmissionaredisconnecteds