1 汽车专业英语课件-汽车基础知识部分-section 1汽车专业英语ppt课件-修改201702278 Chapter 4

复习,自动变速器英文专业词汇AT的组成，主要部件名称AMT组成、主要部件名称DCTCVT的基本结构翻译句子,学习内容,本节课学习内容、目标和重点难点,学习目标,难点重点,Chapter4SteeringandSuspensionSystems,1.掌握转向、悬架系统的基本组成、类型、各系统主要零件的英文名称2.提高翻译技巧，能较熟练翻译课文,1.重点：转向、悬架系统的基本组成、类型、各系统主要零件的英文名称2.难点：电动转向系统,Chapter4SteeringandSuspensionSystems,4.1SteeringSystem1.BasicPartsofSteeringSystem2.TypesofSteeringSystem3.PowerSteeringSystems4.2SuspensionSystems1.BasicPartsofSuspensionSystem2.Frontsuspension3.RearSuspension,Chapter4SteeringandSuspensionSystems4.1SteeringSystem,2.4.1NewWordsandPhrases,Chapter4SteeringandSuspensionSystems4.1SteeringSystem,Chapter4SteeringandSuspensionSystems4.1SteeringSystem,Chapter4SteeringandSuspensionSystems4.1SteeringSystem,Thesteeringsystemisdesignedtoallowthedrivertomovethefrontwheelstotherightorleftwithaminimumofeffortandwithoutexcessivemovementofthesteeringwheel.Althoughthedrivercanmovethewheelseasily,roadshocksarenottransmittedtothedriver.1.BasicPartsofSteeringSystemThebasicsteeringsystem(Figure4-1)canbedividedintothreemainassemblies:Thespindleandsteeringarmassemblies.Thelinkageassemblyconnectingthesteeringarmsandsteeringgear.Thesteeringwheel,steeringshaft,andsteeringgearassembly.,2.4.2Text,Chapter4SteeringandSuspensionSystems4.1SteeringSystem,Figure4-1Basicpartsofsteeringsystem,Chapter4SteeringandSuspensionSystems4.1SteeringSystem,2.TypesofSteeringSystemTherearetwotypesofsteeringsystems:manualsteeringandpowersteeringsystems.Inthemanualsteeringsystems,driverdoesalltheworkofturningthesteeringwheel,steeringgear,andtires.Inthepowersteeringsystems,hydraulicorelectricpower-assistedsteeringisusedtoreducetheeffortrequiredbyturningthesteeringwheel.Therearethreetypesofthesteeringgearsinuse:recirculatingballsteeringgear,worm-and-rollersteeringgearandrack-and-pinionsteeringgear.3.PowerSteeringSystemsHydrauliclack-and-pinionpowersteeringsystem.Thissystemconsistsofmechanicalrack-and-pinionsteeringgear,hydraulicworkingcylinderswithworkingplungers,rotaryslidevalve,oilpump,pressure-limitingvalveandoilreservoir(Figure4-2).,Chapter4SteeringandSuspensionSystems4.1SteeringSystem,Figure4-2Ahydraulicrack-and-pinionpowersteeringsystemwithrotaryslidevalve,Chapter4SteeringandSuspensionSystems4.1SteeringSystem,Electro-hydraulicpowersteeringsystem-Servotronic.Servotronicisanelectronicallycontrolledrack-and-pinionsteeringsysteminwhichthehydraulicassistingforcesareinfluencedbythedrivingspeed.Atlowdrivingspeeds,thefullassistingforceofthehydraulicrack-andpinionsteeringtakeseffect.Thehydraulicassistingforceisreducedasdrivingspeedincreases.So,Servotronicisaspeed-sensitivepowersteering.Servotronicconsistsofelectronicspeedometer,ECU,hydraulicrack-and-pinionsteeringgear,oilreservoir,electro-hydraulicconverterandoilpump(Figure4-3).,Chapter4SteeringandSuspensionSystems4.1SteeringSystem,Figure4-3Servotronic-aelectro-hydraulicpowersteeringsystem,Chapter4SteeringandSuspensionSystems4.1SteeringSystem,Electricpowersteering-Servolectric.WithServolectric(Figure4-4),theassistingforceisgeneratedbyanelectronicallycontrolledelectricmotor.Theelectricmotorisonlyswitchedonwhenrequired.Thesteeringtorqueappliedbythedriverismeasuredviaatorsionrodwithatorquesensorandinadditionthespeedismeasuredviaaspeedsensor.ThetwosignalsarefedtotheECU.TheECUcalculatesthetorquerequiredanditsforce-transferdirectionusingstoredprogrammapsandsendstherelevantoutputsignalstotheelectricmotor.Thelattergeneratesanassistingtorquewhichistransformedbyaworm-gearpairandtransmittedtotherackand-pinionsteeringgear.,Chapter4SteeringandSuspensionSystems4.1SteeringSystem,Figure4-4Servolectric-aelectricpowersteeringsystem,Chapter4SteeringandSuspensionSystems4.2SuspensionSystems,4.2.1NewWordsandPhrases,Chapter4SteeringandSuspensionSystems4.2SuspensionSystems,Ifavehiclesaxleswerebolteddirectlytoitsframeorbody,everyroughspotontheroadwouldtransmitaforcethroughoutthevehicle.Ridingwouldbeuncomfortable,andhandlingatfreewayspeedswouldbeimpossible.1.BasicPartsofSuspensionSystemSprings.Everyvehiclehasspringsofsomekindbetweentheframeorbodyandtheaxles.Therearethreetypesofspringsingeneralusetoday:leafspring,coilspring,andtorsionbar.Twodifferenttypesofspringscanbeusedononevehicle.ShockAbsorbers.Whenthevehicleistravelingforwardonalevelsurfaceandthewheelsstrikeabump,thespringisrapidlycompressed(coilsprings)ortwisted(leafspringsandtorsionbars).Thespringwillattempttoreturntoitsnormalloadedlength.,4.2.2Text,Chapter4SteeringandSuspensionSystems4.2SuspensionSystems,Insodoing,itwillrebound,causingthebodyofthevehicletobelifted.Theweightofthevehiclethenpushesthespringdownafterthespringrebounds.Thiscausesthespringtoreboundagain.Thisprocess,calledspringoscillation,graduallydiminishesuntilthevehicleisfinallystill.Springoscillationcanaffecthandlingandridequalityandmustbecontrolled.Shockabsorbersareusedtoattenuatetheoscillation.ControlArms.Allvehicleshaveeithercontrolarmsorstrutstokeepthewheelassemblyintheproperposition.Thecontrolarmsandstrutsallowthewheeltomoveupanddownwhilepreventingitfrommovinginanyotherdirection.,Chapter4SteeringandSuspensionSystems4.2SuspensionSystems,2.Frontsuspension前悬架Almostallmodernfrontsuspensionsystemsareindependent.Withanindependentsuspension,eachfrontwheelisfreetomoveupanddownwithaminimumeffectontheotherwheel.Inanindependentsuspensionsystem,thereisalsofarlesstwistingmotionimposedontheframethaninasystemwithasolidaxle.ThetwomajortypesofindependentfrontsuspensionaretheconventionalfrontsuspensionandtheMcPhersonstrutfrontsuspension.ConventionalFrontSuspension.Intheconventionalfrontsuspensionsystem,oneortwocontrolarmsareusedateachwheel(Figure4-5).Inmostsystems,thecoilspringsaremountedbetweenthevehiclesframeandthelowercontrolarm.Inatorsionbarfrontsuspensionsystem(Figure4-6),thelowerarmmovesupward,ittwiststhetorsionbar.,Chapter4SteeringandSuspensionSystems4.1SteeringSystem,Figure4-5Atypicalindependentfrontsuspension,Chapter4SteeringandSuspensionSystems4.1SteeringSystem,Figure4-6Atorsionbarfrontsuspensionsystem,Chapter4SteeringandSuspensionSystems4.1SteeringSystem,McPhersonStrutFrontSuspension.Mostmodernvehicles,especiallythosewithfront-wheeldrive,usetheMcPhersonstrutfrontsuspensionsystems(Figure4-7).TheentireMcPhersonstrutassemblyisattachedtothesteeringknuckleatthelowerpartofthepedestal.ThebottomoftheMcPhersonstrutassemblyisattachedtothesinglecontrolarmthroughaballjoint.TheadvantageoftheMcPhersonstrutisitscompactdesign,whichallowsmoreroomforserviceonsmallcarbodies.SolidAxleFrontSuspension.Theuseofthesolidaxlefrontsuspension(ordependentsuspension)isgenerallyconfinedtotrucksandoff-roadvehicles.Thissystemusesasoliddeadaxle(doesnotturnwithwheels)withaleafspringateachside.,Chapter4SteeringandSuspensionSystems4.1Steering