外文翻譯--汽車懸架如何工作.doc_第1頁
外文翻譯--汽車懸架如何工作.doc_第2頁
外文翻譯--汽車懸架如何工作.doc_第3頁
外文翻譯--汽車懸架如何工作.doc_第4頁
外文翻譯--汽車懸架如何工作.doc_第5頁
已閱讀5頁,還剩6頁未讀, 繼續(xù)免費閱讀

付費下載

下載本文檔

版權(quán)說明:本文檔由用戶提供并上傳,收益歸屬內(nèi)容提供方,若內(nèi)容存在侵權(quán),請進行舉報或認領(lǐng)

文檔簡介

英文原文HowCarSuspensionWorkByWilliamHarrisUniversityofMichiganWhenpeoplethinlyofautomobileperformance,theynormallythinkofhorsepower,torqueandzero-to-60acceleration.Butallofthepowergeneratedbyapistonengineisuselessifthedriercantcontrolthecar.Thatswhyautomobileengineersturnedtheirattentiontothesuspensionsystemalmostassoonastheyhadmasteredthefour-Strokeinternalcombustionengine.Double-wishbonesuspensiononHondaAccord2005CoupeThejobofacarsuspensionistomaximizethefrictionbetweenthetiresandtheroadsurface,toprovidesteeringstabilitywithgoodhandlingandtoensurethecomfortofthepassengers.Inthisarticle,wellexplorehowcarSuspensionswork,howtheyreevolvedovertheyearsandwherethedesignofsuspensionsisheadedinthefuture.1.VehicleDynamicsIfaroadwereperfectlyt1at,withnoirregularities,suspensionswouldntbenecessary.Butroadsarefarfromt1at.Evenfreshlypavedhighwayshavesubtleimperfectionsthatcaninteractwiththewheelsofacar.Itstheseimperfectionsthatapplyforcestothewheels.AccordingtoNewtonslawsofmotion,allforceshavebothmagnitudeanddirection.Abumpintheroadcausesthewheeltomoveupanddownperpendiculartotheroadsurface.Themagnitude,ofcourse,dependsonwhetherthewheelisStrikingagiantbumporatinyspeck.Eitherway,theca.rwheelexperiencesaverticalaccelerationasitpassesoveranimperfection.Withoutaninterveningstructure,allofwheelsverticalenergyistransferredtotheframe,whichmovesintheSamedirection.Insuchasituation,thewheelscanlosecontactwiththeroadcompletely.Then,underthedownwardforceofgravity,wheelscanslambackintotheroadsurface.Whatyouneedisasystemthatabsorbtheenergyoftheverticallyacceleratedwheel,allowingtheframeandbodytorideundisturbedwhilethewheelsfollowbumpsintheroad.TheStudyofthefarcesatworkanamovingcariscalledvehicledynamics,andyouneedtosuspensionisnecessaryofneedtounderstandsameoftheseconceptsinordertoappreciatewhyanecessaryinthefirstplace.MastautomobileengineersconsiderthemovingcarPramtwoperspectives:1)Ride-acarsabilitytosmoothoutabumpyroad2)Handling-acarsabilitytosafelyaccelerate,brakeandcornerThesetwocharacteristicscanbefurtherdescribedinthreeimportantprinciples-roadisolation,roadholdingandcornering.Thetablebelowdescribestheseprinciplesandhowengineersattempttosolvethechallengesuniquetoeach.Acarssuspension,withitsvariouscomponents,providesalloftheSolutionsdescribed.2.TheChassisSystemThesuspensionofacarisactuallypartofthechassis,whichcomprisesalloftheimportantsystemslocatedbeneaththecarsbody.figure2-1ChassisThesesystemsinclude:1)Theframe-structural,load-carryingcomponentthatsupportsthecarsengineandbody,whichareinturnsupportedbythesuspension2)TheSuspensionsystem-setupthatsupportsweight,absorbsanddampensshockandhelpsmaintaintirecontact3)Thesteeringsystem-mechanismthatenablesthedrivertoguideanddirectthevehicle4)Thetiresandwheels-componentsthatmakevehiclemotionpossiblebywayofgripand/orfrictionwiththeroadSothesuspensionisjustoneofthemajorsystemsinanyvehicle.Withthisbig-pictureoverviewinmind,itstimetolookatthethreefundamentalcomponentsofanysuspension:springs,dampersandanti-swaybars.3.springsTodaysspringingsystemsarebasedononeoffourbasicdesign:1)Coilspring-Thisisthemastcommontypeofspringandis,inessence,aheavy-dutytorsionbarcoiledaroundanaxis.Coilspringscompressandexpandtoabsorbthemotionofthewheels.2)Leafspring-Thistypeofspringconsistsofseverallayersofmetal(calledleaves)boundtogethertoactasasingleunit.Leafspringswerefirstusedonhorse-drawncarriagesandwerefoundanmostAmericanautomobilesuntil1985.Theyarestillusedtodayonmosttrucksandheavy-dutyvehicles.3)Torsionbars-TorsionbarsusethetwistingpropertiesofasteelGartoprovidecoil-spring-likeperformance.Thisishowtheywork:Oneendofabarisanchoredtothevehicleframe.Theotherendi5attachedtoawishbone,whichactslikealeverthatmaresperpendiculartothetorsionbar.Whenthewheelhitsabump,verticalmotionistransferredtothewishboneandthen,throughtheleveringaction,tothetorsionbar.Thetorsionbarthentwistsalongitsaxistoprovidethespringfarce.Europeancaretakersusedthissystemextensively,asdidPackardandChryslerintheUnitedStates,throughthe1950sand1960s.4)Airsprings-AirSprings,whichconsistofacylindricalchamberofairpositionedbetweenthewheelandthecarsbody,usethecompres5irequalitiesofairtoabsorbwheelvibrations.Theconceptisactuallymorethanacenturyoldandcouldbefoundanhorse-drawnbuggies.Airspringsfromthiseraweremadefromair-filled,leatherdiaphragms,muchlikeabellows;theywerereplacedwithmolded-rubberairspringsinthe1930s.Basedonwherespringsarelocatedonacar-i.e.,betweenthewheelsandtheframe-engineersoftenfinditconvenienttotalkaboutthesprungmassandtheunsprungmass.4.SprungandUnsprungMassThesprungmassisthemassofthevehiclesupportedanthesprings,whiletheunsprungmassislooselydefinedasthemassbetweentheroadandthesuspensionSprings.Thestiffnessofthespringsaffectshowthesprungmassrespondswhilethecarisbeingdriven.Looselysprungcars,suchasluxurycarsthinkLincolnTawsCard,canSwallowbumpsandprovideasuper-smoothride;however,suchacarisprunetodiveandsquatduringbrakingandaccelerationandtendstoexperiencebodyawayorrollduringcornering.Tightlysprungcars,suchassportscars(thinkMazdaMiata),arelessforgivingonbumpyroads,buttheyminimizebodymotionwell,whichmeanstheycanbedrivenaggressively,evenaroundcorners.So,whilespringsbythemselvesseemlikesimpledevices,designingandimplementingthemonacartobalancepassengercomfortwithhandlingisacomplextask.Andtomakemattersmorecomplex,springsalonecantprovideaperfectlysmoothride.Why?BecauseSpringsaregreatatabsorbingenergy,butnotsogoodatdissipatingit.Otherstructures,knownasdampers,arerequiredtodothis.5.ShackAbsorbersUnlessadampeningstructureispresent,acarspringwillextendandreleasetheenergyitabsorbsfromabumpatanuncontrolledrate.Thespringwillcontinuetobounceatitsnaturalfrequencyuntilalloftheenergyoriginallyputintoitisusedup.Asuspensionbuiltanspringsalonewouldmakeforanextremelybouncyrideand,dependingantheterrain,anuncontrollablecar.Entertheshackabsorber,orsnubber,adevicethatcontrolsunwantedspringmotionthroughaprocessknownasdampening.Shockabsorbersslowdownandreducethemagnitudeofvibratorymotionsbyturningthekineticenergyofsuspensionmovementintoheatenergythatcanliedissipatedthroughhydraulicfluid.Tounderstandhowthisworks,itsbesttolookinsideashackabsorbertoseeitsstructureandfunction.Ashockabsorberisbasicallyanoilpumpplacedbetweentheframeofthecarandthewheels.Theuppermountoftheshockconnectstotheframe(i.e.,thesprungweight),whilethelowermountconnectstotheaxle,nearthewheel(i.e.,theunsprungweight).Inatwin-tubedesign,oneofthemostcommontypesofshock)absorbers,theuppermountisconnectedtoapistonrod,whichinturnisconnectedtoapiston,whichinturnsitsinatubefilledwithhydraulicfluid.Theinnertubeisknownasthepressuretube,andtheoutertubeisknownasthereservetube.Thereservetubestoresexcesshydraulicfluid.Whenthecarwheelencountersabumpintheroadandcausesthespringytocoilanduncoil,theenergyofthespringistransferredtotheshockabsorberthroughtheuppermount,downthroughthepistonrodandintothepiston-Orificesperforatethepistonandallowfluidtoleakthroughasthepistonmovesupanddowninthepressuretube.Becausetheorificesarerelativelytiny,onlyasmallamountoffluid,undergreatpressure,passesthrough.Thisslowsdownthepiston,whichinturnslowsdownthespring.Shockabsorberswor

溫馨提示

  • 1. 本站所有資源如無特殊說明,都需要本地電腦安裝OFFICE2007和PDF閱讀器。圖紙軟件為CAD,CAXA,PROE,UG,SolidWorks等.壓縮文件請下載最新的WinRAR軟件解壓。
  • 2. 本站的文檔不包含任何第三方提供的附件圖紙等,如果需要附件,請聯(lián)系上傳者。文件的所有權(quán)益歸上傳用戶所有。
  • 3. 本站RAR壓縮包中若帶圖紙,網(wǎng)頁內(nèi)容里面會有圖紙預覽,若沒有圖紙預覽就沒有圖紙。
  • 4. 未經(jīng)權(quán)益所有人同意不得將文件中的內(nèi)容挪作商業(yè)或盈利用途。
  • 5. 人人文庫網(wǎng)僅提供信息存儲空間,僅對用戶上傳內(nèi)容的表現(xiàn)方式做保護處理,對用戶上傳分享的文檔內(nèi)容本身不做任何修改或編輯,并不能對任何下載內(nèi)容負責。
  • 6. 下載文件中如有侵權(quán)或不適當內(nèi)容,請與我們聯(lián)系,我們立即糾正。
  • 7. 本站不保證下載資源的準確性、安全性和完整性, 同時也不承擔用戶因使用這些下載資源對自己和他人造成任何形式的傷害或損失。

最新文檔

評論

0/150

提交評論