手动变速器基础外文文献翻译、中英文翻译、外文翻译.pdf

附录

附录A英语科技文献

ManualTransmissionBasics

It'snosecretthatcarswithtransmissionsmanualareusuallymorefuntodrivethan
theirautomatic-equippedcounterparts.Ifyouhaveevenapassinginterestintheactof
driving,thenchancesareyoualsoappreciateafine-shiftingmanualgearbox.Buthowdoes
amanualtransactuallywork?Withourprimeronautomatics(orslushboxes,asdetractors
callthem)availableforyourperusal,wethoughtitwouldbeagoodideatoprovidea
companionoverviewonmanualtrannies,too.
Abriefhistorylessonshowsthatmanualtransmissionsprecededautomaticsbyseveral
decades.Infact,upuntilGeneralMotorsofferedanautomaticin1938,allcarswereofthe
shift-it-yourselfvariety.Whileit'slogicalformanytypesoftoday'svehiclestobeequipped
withanautomatic--suchasafull-sizesedan,SUVorpickup--thefactremainsthat
nothingismoreofathrilltodrivethanatautlysuspendedsportsedan,sportcoupeor
two-seaterequippedwithaprecise-shiftingfive-orsix-speedgearbox.It'swhatmakescars
suchasaCorvette,Mustang,MiataoranyBMWsedanorcoupesomeofthemost
fun-to-drivecarsavailabletoday.
Weknowwhichtypesofcarshavemanualtrannies.Nowlet'stakealookathowthey
work.Fromthemostbasicfour-speedmanualinacarfromthe'60stothemosthigh-tech
six-speedinacaroftoday,theprinciplesofamanualgearboxarethesame.Thedrivermust
shiftfromgeartogear.Normally,amanualtransmissionboltstoaclutchhousing(orbell
housing)that,inturn,boltstothebackoftheengine.Ifthevehiclehasfront-wheeldrive,
thetransmissionstillattachestotheengineinasimilarfashionbutisusuallyreferredtoasa
transaxle.Thisisbecausethetransmission,differentialanddriveaxlesareonecomplete
unit.Inafront-wheel-drivecar,thetransmissionalsoservesaspartofthefrontaxleforthe
frontwheels.Intheremainingtext,atransmissionandtransaxlewillbothbereferredto
usingthetermtransmission.

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Thefunctionofanytransmissionistransferringenginepowertothedriveshaftandrear
wheels(oraxlehalfshaftsandfrontwheelsinafront-wheel-drivevehicle).Gearsinsidethe
transmissionchangethevehicle'sdrive-wheelspeedandtorqueinrelationtoenginespeed
andtorque.Lower(numericallyhi