汽车专业英语(幻灯片)chapter 5 mt(3.3.1)

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1、1)Themodernautomobileengineisapowerful,lightweight,anddependablepowerplant.However,itisnotperfectforthreereasons.First,modernenginesdonotproducemuchtorqueatlowenginespeeds.Second,enginesproducemaximumtorquebetween2000-3000r/min.Asaresult,enginesoperatebestonlywithin

2、thisfairlynarrowrange.Third,muchmoreforceisneededtomoveacarfromrestthantokeepitmovingonceitisstarted.Thus,thevehicleneedsawiderrangeoftorquethanisavailablefromtheengine.新型的汽车发动机动力强劲、质量轻便而且动力性能可靠。然而它美中不足的原因有三个。首先，新型发动机低速时产生的转矩较小．其次，发动机在每分钟2000-3000转时转矩最大．结果，发动机只能在这个相

3、当狭窄的转速范围内工作良好．第三，起动汽车比它起动后保持其运动需要的力大．因此，汽车需要的转距比发动机提供的转距范围大．Review1:Whyisatransmissionneededinanautomobile?Review2:What’sthefunctionoftransmission?ChangestheenginetorqueReversesthevehiclemovementDisengagesthedrive3.3transmissionReview3:Listthetypesoftransmission.Fin

4、iteInfiniteMT＝ManualTransmission（手动变速器）AT＝AutomaticTransmission（自动变速器）AMT＝AutomaticMechanicalTransmission（液力机械变速器）CVT＝ContinuouslyVariableTransmission（无级变速器）2)Insimpleterms,atransmissionmultipliesenginetorqueand---throughgears---sendsthatpowertothedriveaxle.Adrivers

5、hiftsorchangesthegearstoincreaseordecreasethetorqueproducedbytheengine.简而言之，变速器利用齿轮扩大发动机的扭矩，向驱动桥传递动力。驾驶员通过换挡来升高或降低发动机的输出扭矩。Review4:What’sthemeaningofgearratio?Gearratio=DrivegearteethnumberDrivengearteethnumberDriveGearDrivenGear3.3.1manualtransmissionReview5:Listth

6、emeshmethodsofmanualtransmission.Sliding-meshTransmissionConstant-meshTransmissionSynchro-meshTransimissionSliding-meshtransmission:Althoughthistypeisrarelyusedtoday,itisincludedbecausethegearlayoutformsthebasicconstructionofmostmodernmanualgearboxes.Thespurgearsare

7、mountedonfourshafts:primaryshaft(inputshaft),layshaft(countershaft),mainshaftandreverseidlershaft.尽管现在几乎不使用滑动啮合变速器，但在这里仍然要提及，因为它是目前大多数手动变速器的雏形。直齿圆柱齿轮装在四个轴上：输入轴，中间轴，输出轴和倒档轴．Review6:Listthetypesoftransmissiongear.Bevelgear锥齿轮Helicalgear斜齿轮Doublehelicalgear人字齿轮Pinionge

8、ar小齿轮Hypoidgear准双曲面齿轮Planetarygear行星齿轮Externalgear外啮合齿轮Internalgear内啮合齿轮4)Sliding-meshtransmission:Inthecaseofasliding-meshgearbox,gearcha