车辆与动力工程外文翻译外文文献英文翻译自动变速器1504.docx

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1、外文资料Evaluation Warning: The document was created with Spire.Doc for .NET.How Automatic Transmissions WorkIf you have ever driven a car with an automatic transmission, then you know that there are two big differences between an automatic transmission and a manual transmission: There is no clutch peda

2、l in an automatic transmission car. Theere is no geaar sshifft iin aan aautoomattic traansmmisssionn caar. Oncce yyou putt thhe ttrannsmiissiion intto ddrivve, eveerytthinng eelsee iss auutommatiic. Both thee auutommatiic ttrannsmiissiion (pllus itss toorquue cconvvertter) annd aa maanuaal traansmmi

3、sssionn (wwithh itts ccluttch) acccommpliish exaactlly tthe samme tthinng, butt thhey do it in tottallly ddifffereent wayys. It turrns outt thhat thee waay aan aautoomattic traansmmisssionn dooes it is abssoluutelly aamazzingg!In thhis artticlle, well worrk oour wayy thhrouugh an auttomaaticc trrans

4、smisssioon. Well staart witth tthe keyy too thhe wwholle ssysttem: pllaneetarry ggearr setts. Theen wwelll ssee howw thhe ttrannsmiissiion is putt toogettherr, llearrn hhow thee coontrrolss woork andd disscusss ssomee off thhe iintrricaaciees iinvoolveed iin cconttrolllinng aa trranssmisssioon.Some

5、BassicssJust likke tthatt off a mannuall trranssmisssioon, thee auutommatiic ttrannsmiissiions pprimmaryy joob iis tto aalloow tthe engginee too opperaate in itss naarroow rrangge oof sspeeeds whiile prooviddingg a widde rrangge oof ooutpput speeedss. Witthouut aa trranssmisssioon, carrs wwoulld bbe

6、 llimiitedd too onne ggearr raatioo, aand thaat rratiio wwoulld hhavee too bee seelecctedd too allloww thhe ccar to traavell att thhe ddesiiredd toop sspeeed. If youu waanteed aa toop sspeeed oof 880 mmph, thhen thee geear rattio wouuld be simmilaar tto tthirrd ggearr inn moost mannuall trranssmisss

7、ioon ccarss. Youvve pprobbablly nneveer ttrieed ddrivvingg a mannuall trranssmisssioon ccar usiing onlly tthirrd ggearr. IIf yyou didd, yyoud qquiccklyy fiind outt thhat youu haad aalmoost no accceleerattionn whhen staartiing outt, aand at higgh sspeeeds, thhe eengiine wouuld be scrreammingg allongg

8、 neear thee reed-llinee. AA caar llikee thhis wouuld weaar oout verry qquiccklyy andd woouldd bee neearlly uundrrivee ablle. So thhe ttrannsmiissiion usees ggearrs tto mmakee moore efffecttivee usse oof tthe engginees torrquee, aand to keeep tthe engginee opperaatinng aat aan aapprroprriatte sspeeed

9、. The kkey diffferrencce bbetwweenn a mannuall annd aan aautoomattic traansmmisssionn iss thhat thee maanuaal ttrannsmiissiion loccks andd unnloccks diffferrentt seets of geaars to thee ouutpuut sshafft tto aachiievee thhe vvariiouss geear rattioss, wwhille iin aan aautoomattic traansmmisssionn, tth

10、e samme sset of geaars prooducces alll off thhe ddifffereent geaar rratiios. Thhe pplannetaary geaar sett iss thhe ddeviice thaat mmakees tthiss poossiiblee inn ann auutommatiic ttrannsmiissiion. GearssThis auttomaaticc trranssmisssioon uusess a sett off geearss, ccallled a ccomppounnd pplannetaary

11、geaar sett, tthatt loookss liike a ssinggle plaanettaryy geear sett buut aactuuallly bbehaavess liike twoo pllaneetarry ggearr setts ccombbineed. It hass onne rringg geear thaat iis aalwaays thee ouutpuut oof tthe traansmmisssionn, bbut it hass twwo ssun geaars andd twwo ssetss off plaanetts. Letss

12、loook at somme oof tthe parrts: Firstt GeearIn fiirstt geear, thhe ssmalllerr suun ggearr iss drriveen cclocckwiise by thee tuurbiine in thee toorquue cconvvertter. Thhe pplannet carrrieer ttriees tto sspinn coounttercclocckwiise, buut iis hheldd sttilll byy thhe oone-wayy cllutcch (whiich onlly aal

13、loows rottatiion in thee cllockkwisse ddireectiion) annd tthe rinng ggearr tuurnss thhe ooutpput. Thhe ssmalll ggearr haas 330 tteetth aand thee riing geaar hhas 72, soo thhe ggearr raatioo iss: Ratioo = -R/S = - 72/30 = -2.44:1So thhe rrotaatioon iis nnegaativve 22.4:1, whiich meaans thaat tthe out

14、tputt diirecctioon wwoulld bbe ooppoositte tthe inpput dirrecttionn. BBut thee ouutpuut ddireectiion is reaallyy thhe ssamee ass thhe iinpuut ddireectiion - thiis iis wwherre tthe triick witth tthe twoo seets of plaanetts ccomees iin. Thee fiirstt seet oof pplannetss enngagges thee seeconnd sset, an

15、nd tthe seccondd seet tturnns tthe rinng ggearr; tthiss coombiinattionn reeverrsess thhe ddireectiion. Yoou ccan seee thhat thiis wwoulld aalsoo caausee thhe bbiggger sunn geear to spiin; butt beecauuse thaat ccluttch is relleassed, thhe bbiggger sunn geear is freee tto sspinn inn thhe ooppoositte d

16、direectiion of thee tuurbiineSeconnd GGearrThis traansmmisssionn dooes sommethhingg reeallly nneatt inn orrderr too geet tthe rattio neeededd foor ssecoond geaar. It actts llikee twwo pplannetaary geaar setts cconnnectted to eacch othher witth aa coommoon pplannet carrrieer. The ffirsst sstagge oof

17、tthe plaanett caarriier acttuallly usees tthe larrgerr suun ggearr ass thhe rringg geear. Soo thhe ffirsst sstagge cconssistts oof tthe sunn (tthe smaalleer ssun geaar), thhe pplannet carrrieer, andd thhe rringg (tthe larrgerr suun ggearr). The iinpuut iis tthe smaall sunn geear; thhe rringg geear (

18、laargee suun ggearr) iis hheldd sttatiionaary by thee baand, annd tthe outtputt iss thhe pplannet carrrieer. so thee foormuula is: 1 + RR/S = 11 + 36/30 = 22.2:1The pplannet carrrieer tturnns 22.2 timmes forr eaach rottatiion of thee smmalll suun ggearr. AAt tthe seccondd sttagee, tthe plaanett caar

19、riier actts aas tthe inpput forr thhe ssecoond plaanettaryy geear sett, tthe larrgerr suun ggearr (wwhicch iis hheldd sttatiionaary) accts as thee suun, andd thhe rringg geear actts aas tthe outtputt, sso tthe geaar rratiio iis:1 / (1 + S/R) = 11 / (1 + 336/772) = 00.677:1 To gett thhe ooverralll re

20、educctioon ffor seccondd geear, wee muultiiplyy thhe ffirsst sstagge bby tthe seccondd, 22.2 x 00.677, tto gget a 11.477:1 redducttionn. TThiss maay ssounnd wwackky, butt itt woorkss. Thirdd GeearMost auttomaaticc trranssmisssioons havve aa 1:1 rratiio iin tthirrd ggearr. YYoull remmembber froom tth

21、e preevioous secctioon tthatt alll wwe hhavee too doo too geet aa 1:1 ooutpput is locck ttogeetheer aany twoo off thhe tthreee ppartts oof tthe plaanettaryy geear. Wiith thee arrranggemeent in thiis ggearr sett itt iss evven eassierr - alll wwe hhavee too doo iss enngagge tthe cluutchhes thaat llock

22、k eaach of thee suun ggearrs tto tthe turrbinne. If booth sunn geearss tuurn in thee saame dirrecttionn, tthe plaanett geearss loockuup bbecaausee thhey cann onnly spiin iin ooppoositte ddireectiionss. TThiss loockss thhe rringg geaar tto tthe plaanetts aand cauusess evveryythiing to spiin aas aa un

23、nit, prroduucinng aa 1:1 rratiio. OveerdrriveeBy deefinnitiion, ann ovverddrivve hhas a ffastter outtputt sppeedd thhan inpput speeed. Itts a sspeeed iincrreasse. In thiis ttrannsmiissiion, enngaggingg thhe ooverrdriive acccompplisshess twwo tthinngs at oncce. If youu reead Howw Toorquue CConvvertte

24、rss Woork, yoou llearrnedd abboutt loockuup ttorqque connverrterrs. In ordder to impprovve eeffiicieencyy, ssomee carrs hhavee a mecchannismm thhat loccks up thee toorquue cconvvertter so thaat tthe outtputt off thhe eengiine goees sstraaighht tto tthe traansmmisssionn. In thhis traansmmisssionn, ww

25、henn ovverddrivve iis eengaagedd, aa shhaftt thhat is atttachhed to thee hoousiing of thee toorquue cconvvertter (whhichh iss boolteed tto tthe flyywheeel of thee ennginne) is connnecctedd byy cllutcch tto tthe plaanett caarriier. Thhe ssmalll ssun geaar ffreeewheeelss, aand thee laargeer ssun geaar

26、 iis hheldd byy thhe ooverrdriive bannd. Notthinng iis cconnnectted to thee tuurbiine; thhe oonlyy innputt coomess frrom thee coonveerteer hhoussingg. LLets ggo bbackk too ouur ccharrt aagaiin, thiis ttimee wiith thee pllaneet ccarrrierr forr innputt, tthe sunn geear fixxed andd thhe rringg geear fo

27、rr ouutpuut. Ratioo = 1 / (11 + S/RR) = 1 / ( 1 + 336/772) = 00.677:1So thhe ooutpput spiins oncce ffor eveery twoo-thhirdds oof aa rootattionn off thhe eengiine. Iff thhe eengiine is turrninng aat 220000 rootattionns pper minnutee (RRPM), tthe outtputt speeed is 30000 RRPM. Thhis alllowss caars to

28、driive at freeewaay sspeeed wwhille tthe engginee sppeedd sttayss niice andd sllow. ReverrseReverrse is verry ssimiilarr too fiirstt geear, exxceppt tthatt innsteead of thee smmalll suun ggearr beeingg drriveen bby tthe torrquee coonveerteer tturbbinee, tthe bigggerr suun ggearr iss drriveen, andd t

29、hhe ssmalll oone freeewhheells iin tthe oppposiite dirrecttionn. TThe plaanett caarriier is helld bby tthe revversse bbandd too thhe hhoussingg. SSo, acccorddingg too ouur eequaatioons froom tthe lasst ppagee, wwe hhavee: Ratioo = -R/S = 722/366 = 2.00:1So thhe rratiio iin rreveersee iss a litttlee

30、leess thaan ffirsst ggearr inn thhis traansmmisssionn. Geaar RRatiios Thhis traansmmisssionn haas ffourr foorwaard geaars andd onne rreveersee geear. Leetss suummaarizze tthe geaar rratiios, innputts aand outtputts: GearInputtOutpuutFixeddGear Rattio1st30-tooothh suun72-tooothh riingPlaneet ccarrrie

31、rr2.4:112nd30-tooothh suunPlaneet ccarrrierr36-tooothh riing2.2:11Planeet ccarrrierr72-tooothh riing36-tooothh suun0.67:1Totall 2nnd1.47:13rd30- aand 36-toooth sunns72-tooothh riing1.0:11ODPlaneet ccarrrierr72-tooothh riing36-tooothh suun0.67:1Reverrse36-tooothh suun72-tooothh riingPlaneet ccarrrier

32、r-2.0:1Hydraauliic SSysttemThe aautoomattic traansmmisssionn inn yoour carr haas tto ddo nnumeerouus ttaskks. Youu maay nnot reaalizze hhow manny ddifffereent wayys iit ooperratees. Forr innstaancee, hheree arre ssomee off thhe ffeatturees oof aan aautoomattic traansmmisssionn: If thhe ccar is in ov

33、eerdrrivee (oon aa foour-speeed traansmmisssionn), thee trranssmisssioon wwilll auutommatiicallly sellectt thhe ggearr baasedd onn veehiccle speeed andd thhrotttlee peedall poosittionn. If yoou aacceelerratee geentlly, shiiftss wiill occcur at lowwer speeedss thhan if youu acccelleraate at fulll tth

34、roottlle. If yoou fflooor tthe gass peedall, tthe traansmmisssionn wiill dowwnshhiftt too thhe nnextt loowerr geear. If yoou mmovee thhe sshifft sseleectoor tto aa loowerr geear, thhe ttrannsmiissiion willl ddownnshiift unllesss thhe ccar is goiing tooo faast forr thhat geaar. If thee caar iis ggoin

35、ng ttoo fasst, it willl wwaitt unntill thhe ccar sloows dowwn aand theen ddownnshiift. If yoou pput thee trranssmisssioon iin ssecoond geaar, it willl nneveer ddownnshiift or up shiift outt off seeconnd, eveen ffromm a commpleete stoop, unllesss yoou mmovee thhe sshifft lleveer. Youuvee prrobaablyy

36、seeen sommethhingg thhat loooks likke tthiss beeforre. It is reaallyy thhe bbraiin oof tthe auttomaaticc trranssmisssioon, mannagiing alll off thhesee fuuncttionns aand morre. Thee paassaagewwayss yoou ccan seee rooutee flluidd too alll tthe diffferrentt coompoonennts in thee trranssmisssioon. Passs

37、aggewaays molldedd innto thee meetall arre aan eeffiicieent wayy too rooutee flluidd; wwithhoutt thhem, maany hosses wouuld be neeededd too coonneect thee vaarioous parrts of thee trranssmisssioon. Firrst, weelll diiscuuss thee keey ccompponeentss off thhe hhydrraullic sysstemm; tthenn weelll seee h

38、how theey wworkk toogettherr.The PPumppAutommatiic ttrannsmiissiionss haave a nneatt puump, caalleed aa geear pummp. Thee puump is usuuallly llocaatedd inn thhe ccoveer oof tthe traansmmisssionn. IIt ddrawws ffluiid ffromm a summp iin tthe botttomm off thhe ttrannsmiissiion andd feeedss itt too thhe

39、 hhydrraullic sysstemm. IIt aalsoo feeedss thhe ttrannsmiissiion cooolerr annd tthe torrquee coonveerteer.The iinneer ggearr off thhe ppumpp hoookss upp too thhe hhoussingg off thhe ttorqque connverrterr, sso iit sspinns aat tthe samme sspeeed aas tthe engginee. TThe outter geaar iis tturnned by the

40、e innnerr geear, annd aas tthe geaars rottatee, ffluiid iis ddrawwn uup ffromm thhe ssumpp onn onne ssidee off thhe ccresscennt aand forrcedd ouut iintoo thhe hhydrraullic sysstemm onn thhe ootheer ssidee. The GGoveernoorThe ggoveernoor iis aa clleveer vvalvve tthatt teellss thhe ttrannsmiissiion ho

41、ww faast thee caar iis ggoinng. It is connnecctedd too thhe ooutpput, soo thhe ffastter thee caar mmovees, thee faasteer tthe govvernnor spiins. Innsidde tthe govvernnor is a sspriing-loaadedd vaalvee thhat opeens in prooporrtioon tto hhow fasst tthe govvernnor is spiinniing - thee faasteer tthe gov

42、vernnor spiins, thhe mmoree thhe vvalvve oopenns. Fluuid froom tthe pummp iis ffed to thee gooverrnorr thhrouugh thee ouutpuut sshafft. The ffastter thee caar ggoess, tthe morre tthe govvernnor vallve opeens andd thhe hhighher thee prresssuree off thhe ffluiid iit lletss thhrouugh. Valvees aand Modd

43、ulaatorrsThrotttlee Vaalvee orr MoodullatoorTo shhiftt prropeerlyy, tthe auttomaaticc trranssmisssioon hhas to knoow hhow harrd tthe engginee iss woorkiing. Thheree arre ttwo diffferrentt waays thaat tthiss iss doone. Soome carrs hhavee a simmplee caablee liinkaage connnecctedd too a thrrotttle vall

44、ve in thee trranssmisssioon. Thee fuurthher thee gaas ppedaal iis ppresssedd, tthe morre ppresssurre iis pput on thee thhrotttlee vaalvee. OOtheer ccarss usse aa vaacuuum mmoduulattor to appply preessuure to thee thhrotttlee vaalvee. TThe moddulaatorr seensees tthe mannifoold preessuure, whhichh dro

45、ops wheen tthe engginee iss unnderr a greeateer lloadd. Manuaal VValvveThe mmanuual vallve is whaat tthe shiift levver hoooks up to. Deepenndinng oon wwhicch ggearr iss seelecctedd, tthe mannuall vaalvee feeedss hyydraauliic ccirccuitts tthatt innhibbit cerrtaiin ggearrs. Forr innstaancee, iif tthe

46、shiift levver is in thiird geaar, it feeeds a ccirccuitt thhat preevennts oveerdrrivee frrom enggagiing. Shiftt VaalveesShiftt vaalvees ssuppply hyddrauulicc prresssuree too thhe ccluttchees aand bannds to enggagee eaach geaar. Thee vaalvee boody of thee trranssmisssioon cconttainns sseveerall shhiftt vaalvees. Thee shhiftt vaalvee deeterrminnes wheen tto sshifft ffromm onne ggearr too thhe nnextt. FFor insstannce, thhe 11 too 2 shiift vallve dettermminees wwhenn too shhiftt frrom firrst to seccondd geear. Thhe sshifft vvalvve iis ppresssurrizeed