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畢 業(yè) 設(shè) 計(jì)(論 文)外 文 參 考 資 料 及 譯 文譯文題目: The Automobile Steering System 汽車轉(zhuǎn)向系統(tǒng) 學(xué)生姓名: 專業(yè): 所在學(xué)院: 指導(dǎo)教師: 職稱: 2013年02月19日The Automobile Steering SystemAlongwithautomobileelectronictechnologyswiftandviolentdevelopment,thepeoplealsodaybydayenhancetothemotorturninghandlingqualityrequest.Themotorturningsystemchanged,thehydraulicpressureboostfromthetraditionalmachinerychanges(HydraulicPowerSteering,iscalledHPS),theelectricallycontrolledhydraulicpressureboostchanges(ElectricHydraulicPowerSteering,iscalledEHPS),developstheelectricallyoperatedbooststeeringsystem(ElectricPowerSteering,iscalledEPS),finallyalsowilltransittothelinecontrolsthesteeringsystem(SteerByWire,willbecalledSBW).Themachinerysteeringsystemisrefersbypilotsphysicalstrengthachievementchangestheenergy,inwhichallpowertransmissionallismechanical,theautomobilechangesthemovementisoperatesthesteeringwheelbythepilot,transmitsthroughthediverterandaseriesofmemberschangesthewheeltorealize.Themechanicalsteeringsystembychangesthecontrolmechanism,thediverterandmajorpartchangesthegearing3tobecomposed.Usuallymaydivideintoaccordingtothemechanicaldiverterform:Thegearracktype,followsroundtheworld-like,thewormbearingadjusterhooptype,thewormbearingadjusterreferssellsthetype.Isthegearracktypeandfollowsusingthebroadesttwokindsroundtheworld-like(usesinneedingtimebigsteeringforce).Infollowsroundtheworld-likeinthediverter,theinputchangesthecircleandtheoutputsteeringarmpivotangleisproportional;Inthegearracktypediverter,theinputchangestheturnandtheoutputrackdisplacementisproportional.Followsroundtheworld-likethediverterbecauseistherollingfrictionform,thusthetransmissionefficiencyisveryhigh,theeaseofoperationalsotheservicelifearelong,moreoverbearingcapacity,thereforewidelyappliesonthetruck.Thegearracktypediverterwithfollowsroundtheworld-likecompares,themostmajorcharacteristicistherigidityisbig,thestructurecompactweightislight,alsothecostislow.Becausethiswaypassesoneasilybythewheelthereactingforcetothesteeringwheel,thereforehastothepavementbehaviorresponsekeenmerit,butsimultaneouslyalso easytohavephenomenaandsoongoonandoscillation,alsoitsloadbearingefficiencyrelativeweak,thereforemainlyappliesonthecompactcarandthepickuptruck,atpresentthemajorityoflowendpassengervehicleusesisthegearracktypemachinerysteeringsystem.Alongwiththevehiclescarryingcapacityincreaseaswellasthepeopletothevehicleshandlingqualityrequestenhancement,thesimplemechanicaltypesteeringsystemwerealreadyunabletomeettheneeds,thepowersteeringsystemariseatthehistoricmoment,itcouldrotatethesteeringwheelwhilethepilottoprovidetheboost,thepowersteeringsystemdividesintothehydraulicpressuresteeringsystemandtheelectricallyoperatedsteeringsystem2kinds.Hydraulicpressuresteeringsystemisatpresentusesthemostwidespreadsteeringsystem.Thehydraulicpressuresteeringsystemincreasedthehydraulicsysteminthemechanicalsystemfoundation,includinghydraulicpump,Vshapebandpulley,drilltubing,feedinstallment,boostinstallmentandcontrolvalve.Itwiththeaidofinthemotorcarenginepoweractuationhydraulicpump,theaircompressorandthegeneratorandsoon,bythefluidstrength,thephysicalstrengthortheelectricpowerincreasesthepilottooperatethestrengthwhichthefrontwheelchanges,enablesthepilottobepossiblenimblytooperatemotorturningfacilely,reducedthelaborintensity,enhancedthetravelsecurity.Thehydraulicpressurebooststeeringsystemfrominventedalreadyhadabouthalfcenturyhistorytothepresent,mightsaywasonekindofmoreperfectsystem,becauseitsworkreliable,thetechnologymaturestillwidelyisapplieduntilnow.Ittakesthepowersupplybythehydraulicpump,afteroilpipe-linecontrolvalvestopowerhydrauliccylinderfeed,throughtheconnectingrodimpetusrotationgearmovement,maychangestheboostthroughthechangecylinderboreandtheflowingtubingheadpressuresizethesize,fromthisachievedchangestheboostthefunction.Thetraditionalhydraulicpressuretypepowersteeringsystemmaydivideintogenerallyaccordingtotheliquidflowform:Ordinaryflowtypeandatmosphericpressuretype2kindoftypes,alsomaydivideintoaccordingtothecontrolvalveformtransfersthevalvetypeandtheslide-valvetype.Alongwithhydraulicpressurepowersteeringsystemonautomobiledailypopularization,thepeopletooperateswhentheportabilityandtheroadfeelingrequestalsodaybydayenhance,howeverthehydraulicpressurepowersteeringsystemhasmanyshortcomingsactually:Becauseitsitselfstructurehaddecideditisunabletoguaranteevehiclesrotatesthesteeringwheelwhenanyoperatingmode,allhastheidealoperationstability,namelyisunablesimultaneouslytoguaranteetimethelowspeedchangestheportabilityandthehighspeedtimeoperationstability.Theautomobilechangesthecharacteristictodrivethepilottechnicaltheinfluencetobeserious;Thesteeringratioisfixed,causesthemotorturningresponsecharacteristicalongwithchangesandsoonvehiclespeed,transverseaccelerationtochange,thepilotmustaimatthemotorturningcharacteristicpeak-to-peakvalueandthephasechangeaheadoftimecarriesoncertainoperationcompensation,thuscontrolstheautomobileaccordingtoitswishtravel.Likethisincreasedpilotsoperationburden,alsocausesinthemotorturningtravelnottohavethesecurityhiddendanger;Buthereafterappearedtheelectricallycontrolledhydraulicboostersystem,itincreasesthevelocitygeneratorinthetraditionalhydraulicpressurepowersteeringsystemfoundation,enablestheautomobilealongwiththevehiclespeedchangeautomaticcontrolforcesize,hastoacertainextentrelaxedthetraditionalhydraulicpressuresteeringsystemexistencequestion.Atpresentourcountryproducesonthecommercialvehicleandthepassengervehicleusesmostlyistheelectricallycontrolledhydraulicpressurebooststeeringsystem,itisquitematureandtheapplicationwidespreadsteeringsystem.Althoughtheelectricallycontrolledhydraulicservoalleviatedthetraditionalhydraulicpressurefromcertaindegreetochangebetweentheportabilityandtheroadfeelingcontradiction,howeveritdidnothavefundamentallytosolvetheHPSsystemexistenceinsufficiency,alongwithautomobilemicroelectronictechnologydevelopment,automobilefueloilenergyconservationrequestaswellasglobalinitiativeenvironmentalprotection,itinaspectandsoonarrangement,installment,leak-proofquality,controlsensitivity,energyconsumption,attritionalreadymoreandmoreobvious,thesteeringsystemturnedtowardstheelectricallyoperatedbooststeeringsystemdevelopment.Theelectricallyoperatedbooststeeringsystemisthepresentmotorturningsystemdevelopmentdirection,itsprincipleofworkis:EPSsystemECUaftercomesfromthesteeringwheeltorquesensorandthevehiclespeedsensorsignalcarriesonanalysisprocessing,controlstheelectricalmachinerytohavethesuitableboosttorque,assiststhepilottocompletechangestheoperation.Inthelastfewyears,alongwiththeelectronictechnologydevelopment,reducesEPSthecosttobecomelargescalepossibly,Japansendsthecarcompany,MitsubishiCarcompany,thisfieldcarcompany,USsDelphiautomobilesystemcompany,TRWCorporationandGermanysZFCorporation.greatly.all.one.after.another.develops.EPS.Mercedes2Benz.and.SiemensAutomotiveTwobigcompaniesinvested65,000,000poundstouseindevelopingEPS,thegoalaretogetherloadacarto2002,yearlyproduce300tenthousandsets,becametheglobalEPSmanufacturer.Sofar,theEPSsystemintheslightpassengervehicle,onthetheaterboxtypevehicleobtainsthewidespreadapplication,andeveryyearby300tenthousandspeeddevelopment.Steeringisthetermappliedtothecollectionofcomponents,linkages,etc.whichallowforavessel(ship,boat)orvehicle(car)tofollowthedesiredcourse.Anexceptionisthecaseofrailtransportbywhichrailtrackscombinedtogetherwithrailroadswitchesprovidethesteeringfunction.Manymoderncarsuserackandpinionsteeringmechanisms,wherethesteeringwheelturnsthepiniongear;thepinionmovestherack,whichisasortoflineargearwhichmesheswiththepinion,.from.side.to.side.This.motion.applies.steering.torque.tothekingpinsofthesteeredwheelsviatierodsandashortleverarmcalledthesteeringarm.Olderdesignsoftenusetherecirculatingballmechanism,whichisstillfoundontrucksandutilityvehicles.Thisisavariationontheolderwormandsectordesign;thesteeringcolumnturnsalargescrew(thewormgear)whichmesheswithasectorofagear,causingittorotateaboutitsaxisasthewormgearisturned;anarmattachedtotheaxisofthesectormovesthepitmanarm,whichisconnectedtothesteeringlinkageandthussteersthewheels.Therecirculatingballversionofthisapparatusreducestheconsiderablefrictionbyplacinglargeballbearingsbetweentheteethofthewormandthoseofthescrew;ateitherendoftheapparatustheballsexitfrombetweenthetwopiecesintoachannelinternaltotheboxwhichconnectsthemwiththeotherendoftheapparatus,thustheyarerecirculated.Therackandpiniondesignhastheadvantagesofalargedegreeoffeedbackanddirectsteeringfeel;italsodoesnotnormallyhaveanybacklash,orslack.Adisadvantageisthatitisnotadjustable,sothatwhenitdoeswearanddeveloplash,theonlycureisreplacement.Therecirculatingballmechanismhastheadvantageofamuchgreatermechanicaladvantage,sothatitwasfoundonlarger,heaviervehicleswhiletherackandpinionwasoriginallylimitedtosmallerandlighterones;duetothealmostuniversaladoptionofpowersteering,however,thisisnolongeranimportantadvantage,leadingtotheincreasinguseofrackandpiniononnewercars.Therecirculatingballdesignalsohasaperceptiblelash,ordeadspotoncenter,whereaminuteturnofthesteeringwheelineitherdirectiondoesnotmovethesteeringapparatus;thisiseasilyadjustableviaascrewontheendofthesteeringboxtoaccountforwear,butitcannotbeentirelyeliminatedorthemechanismbeginstowearveryrapidly.Thisdesignisstillinuseintrucksandotherlargevehicles,whererapidityofsteeringanddirectfeelarelessimportantthanrobustness,maintainability,andmechanicaladvantage.Themuchsmallerdegreeoffeedbackwiththisdesigncanalsosometimesbeanadvantage;driversofvehicleswithrackandpinionsteeringcanhavetheirthumbsbrokenwhenafrontwheelhitsabump,causingthesteeringwheel tokicktoonesidesuddenly(leadingtodrivinginstructorstellingstudentstokeeptheirthumbsonthefrontofthesteeringwheel,ratherthanwrappingaroundtheinsideoftherim).Thiseffectisevenstrongerwithaheavyvehiclelikeatruck;recirculatingballsteeringpreventsthisdegreeoffeedback,justasitpreventsdesirablefeedbackundernormalcircumstances.ThesteeringlinkageconnectingthesteeringboxandthewheelsusuallyconformstoavariationofAckermannsteeringgeometry,toaccountforthefactthatinaturn,theinnerwheelisactuallytravelingapathofsmallerradiusthantheouterwheel,sothatthedegreeoftoesuitablefordrivinginastraightpathisnotsuitableforturns.Asvehicleshavebecomeheavierandswitchedtofrontwheeldrive,theefforttoturnthesteeringwheelmanuallyhasincreased-oftentothepointwheremajorphysicalexertionisrequired.Toalleviatethis,automakershavedevelopedpowersteeringsystems.Therearetwotypesofpowersteering.system.hydraulicandelectric/electronic.Thereisalsoahydraulic-electrichybridsystempossible.Ahydraulicpowersteering(HPS)useshydraulicpressuresuppliedbyanengine-drivenpumptoassistthemotionofturningthesteeringwheel.Electricpowersteering(EPS)ismoreefficientthanthehydraulicpowersteering,sincetheelectricpowersteeringmotoronlyneedstoprovideassistwhenthesteeringwheelisturned,whereasthehydraulicpumpmustrunconstantly.InEPStheassistleveliseasilytunabletothevehicletype,roadspeed,andevendriverpreference.Anaddedbenefitistheeliminationofenvironmentalhazardposedbyleakageanddisposalofhydraulicpowersteeringfluid.Anoutgrowthofpowersteeringisspeedadjustablesteering,wherethesteeringisheavilyassistedatlowspeedandlightlyassistedathighspeed.Theautomakersperceivethatmotoristsmightneedtomakelargesteeringinputswhilemanoeuveringforparking,butnotwhiletravelingathighspeed.ThefirstvehiclewiththisfeaturewastheCitronSMwithitsDiravilayout,althoughratherthanalteringtheamountofassistanceasinmodernpowersteeringsystems,italteredthepressureonacentringcamwhichmadethesteeringwheeltrytospringbacktothestraight-aheadposition.Modernspeed-adjustablepowersteeringsystemsreducethepressurefedtotheramasthespeedincreases,givingamoredirectfeel.Thisfeatureisgraduallybecomingcommonplaceacrossallnewvehicles.Four-wheelsteering(orallwheelsteering)isasystememployedbysomevehiclestoincreasevehiclestabilitywhilemaneuveringathighspeed,ortodecreaseturningradiusatlowspeed.Inmostfour-wheelsteeringsystems,therearwheelsaresteeredbyacomputerandactuators.TherearwheelsgenerallycannotturnasfarastheAlternatively,severalsystems,includingDelphisQuadrasteerandthesysteminHondasPreludeline,allowfortherearwheelstobesteeredintheoppositedirectionasthefrontwheelsduringlowspeeds.Thisallowsthevehicletoturninasignificantlysmallerradiussometimescriticalforlargetrucksorvehicleswithtrailers.隨著汽車電子技術(shù)的迅猛發(fā)展,人們對汽車轉(zhuǎn)向操縱性能的要求也日益提高。汽車轉(zhuǎn)向系統(tǒng)已從傳統(tǒng)機(jī)械轉(zhuǎn)向、液壓助力轉(zhuǎn)向(HydraulicPowerSteering,簡稱HPS)、電控液壓助力轉(zhuǎn)向(ElectricHydraulicPowerSteering,簡稱EHPS),發(fā)展到電動助力轉(zhuǎn)向系統(tǒng)(ElectricPowerSteering,簡稱EPS),最終還將過渡到線控轉(zhuǎn)向系統(tǒng)(SteerByWire,簡稱SBW)。機(jī)械轉(zhuǎn)向系統(tǒng)是指以駕駛員的體力作為轉(zhuǎn)向能源,其中所有傳力件都是機(jī)械的,汽車的轉(zhuǎn)向運(yùn)動是由駕駛員操縱方向盤,通過轉(zhuǎn)向器和一系列的桿件傳遞到轉(zhuǎn)向車輪而實(shí)現(xiàn)的。機(jī)械轉(zhuǎn)向系由轉(zhuǎn)向操縱機(jī)構(gòu)、轉(zhuǎn)向器和轉(zhuǎn)向傳動機(jī)械3大部分組成。通常根據(jù)機(jī)械式轉(zhuǎn)向器形式可以分為:齒輪齒條式、循環(huán)球式、蝸桿滾輪式、蝸桿指銷式。應(yīng)用最廣的兩種是齒輪齒條式和循環(huán)球式(用于需要較大的轉(zhuǎn)向力時(shí))。在循環(huán)球式轉(zhuǎn)向器中,輸入轉(zhuǎn)向圈與輸出的轉(zhuǎn)向搖臂擺角是成正比的;在齒輪齒條式轉(zhuǎn)向器中,輸入轉(zhuǎn)向圈數(shù)與輸出的齒條位移是成正比的。循環(huán)球式轉(zhuǎn)向器由于是滾動摩擦形式,因而正傳動效率很高,操作方便且使用壽命長,而且承載能力強(qiáng),故廣泛應(yīng)用于載貨汽車上。齒輪齒條式轉(zhuǎn)向器與循環(huán)球式相比,最大特點(diǎn)是剛性大,結(jié)構(gòu)緊湊重量輕,且成本低。由于這種方式容易由車輪將反作用力傳至轉(zhuǎn)向盤,所以具有對路面狀態(tài)反應(yīng)靈敏的優(yōu)點(diǎn),但同時(shí)也容易產(chǎn)生打手和擺振等現(xiàn)象,且其承載效率相對較弱,故主要應(yīng)用于小汽車及輕型貨車上,目前大部分低端轎車采用的就是齒輪齒條式機(jī)械轉(zhuǎn)向系統(tǒng)。隨著車輛載重的增加以及人們對車輛操縱性能要求的提高,簡單的機(jī)械式轉(zhuǎn)向系統(tǒng)已經(jīng)無法滿足需要,動力轉(zhuǎn)向系統(tǒng)應(yīng)運(yùn)而生,它能在駕駛員轉(zhuǎn)動方向盤的同時(shí)提供助力,動力轉(zhuǎn)向系統(tǒng)分為液壓轉(zhuǎn)向系統(tǒng)和電動轉(zhuǎn)向系統(tǒng)2種。其中液壓轉(zhuǎn)向系統(tǒng)是目前使用最為廣泛的轉(zhuǎn)向系統(tǒng)。液壓轉(zhuǎn)向系統(tǒng)在機(jī)械系統(tǒng)的基礎(chǔ)上增加了液壓系統(tǒng),包括液壓泵、V形帶輪、油管、供油裝置、助力裝置和控制閥。它借助于汽車發(fā)動機(jī)的動力驅(qū)動液壓泵、空氣壓縮機(jī)和發(fā)電機(jī)等,以液力、氣力或電力增大駕駛員操縱前輪轉(zhuǎn)向的力量,使駕駛員可以輕便靈活地操縱汽車轉(zhuǎn)向,減輕了勞動強(qiáng)度,提高了行駛安全性。液壓助力轉(zhuǎn)向系統(tǒng)從發(fā)明到現(xiàn)在已經(jīng)有了大約半個世紀(jì)的歷史,可以說是一種較為完善的系統(tǒng),由于其工作可靠、技術(shù)成熟至今仍被廣泛應(yīng)用。它由液壓泵作為動力源,經(jīng)油管道控制閥向動力液壓缸供油,通過活塞桿帶動轉(zhuǎn)向機(jī)構(gòu)動作,可通過改變缸徑及油壓的大小來改變助力的大小,由此達(dá)到轉(zhuǎn)向助力的作用。傳統(tǒng)液壓式動力轉(zhuǎn)向系統(tǒng)一般按液流的形式可以分為:常流式和常壓式2種類型,也可根據(jù)控制閥形式分為轉(zhuǎn)閥式和滑閥式。隨著液壓動力轉(zhuǎn)向系統(tǒng)在汽車上的日益普及,人們對操作時(shí)的輕便性和路感的要求也日益提高,然而液壓動力轉(zhuǎn)向系統(tǒng)卻存在許多的缺點(diǎn):由于其本身的結(jié)構(gòu)決定了其無法保證車輛在任何工況下轉(zhuǎn)動轉(zhuǎn)向盤時(shí),都有較理想的操縱穩(wěn)定性,即無法同時(shí)保證低速時(shí)的轉(zhuǎn)向輕便性和高速時(shí)的操縱穩(wěn)定性;汽車的轉(zhuǎn)向特性受駕駛員駕駛技術(shù)的影響嚴(yán)重;轉(zhuǎn)向傳動比固定,使汽車轉(zhuǎn)向響應(yīng)特性隨車速、側(cè)向加速度等變化而變化,駕駛員必須提前針對汽車轉(zhuǎn)向特性幅值和相位的變化進(jìn)行一定的操作補(bǔ)償,從而控制汽車按其意愿行駛。這樣增加了駕駛員的操縱負(fù)擔(dān),也使汽車轉(zhuǎn)向行駛中存在不安全隱患;而此后出現(xiàn)了電控液壓助力系統(tǒng),它在傳統(tǒng)的液壓動力轉(zhuǎn)向系統(tǒng)的基礎(chǔ)上增加速度傳感器,使汽車能夠隨著車速的變化自動調(diào)節(jié)操縱力的大小,在一定程度上緩和了傳統(tǒng)的液壓轉(zhuǎn)向系統(tǒng)存在的問題。目前我國生產(chǎn)的商用車和轎車上采用的大多是電控液壓助力轉(zhuǎn)向系統(tǒng),它是比較成熟和應(yīng)用廣泛的轉(zhuǎn)向系統(tǒng)。盡管電控液壓助力裝置從一定程度上緩解了傳統(tǒng)的液壓轉(zhuǎn)向中輕便性和路感之間的矛盾,然而它還是沒有從根本上解決HPS系統(tǒng)存在的不足,隨著汽車微電子技術(shù)的發(fā)展,汽車燃油節(jié)能的要求以及全球性倡導(dǎo)環(huán)保,其在布置、安裝、密封性、操縱靈敏度、能量消耗、磨損與噪聲等方面的不足已越來越明顯,轉(zhuǎn)向系統(tǒng)向著電動助力轉(zhuǎn)向系統(tǒng)發(fā)展。電動助力轉(zhuǎn)向系統(tǒng)是現(xiàn)在汽車轉(zhuǎn)向系統(tǒng)的發(fā)展方向,其工作原理是:EPS系統(tǒng)的ECU對來自轉(zhuǎn)向盤轉(zhuǎn)矩傳感器和車速傳感器的信號進(jìn)行分析處理后,控制電機(jī)產(chǎn)生適當(dāng)?shù)闹D(zhuǎn)矩,協(xié)助駕駛員完成轉(zhuǎn)向操作。近幾年來,隨著電子技術(shù)的發(fā)展,大幅度降低EPS的成本已成為可能,日本的大發(fā)汽車公司、三菱汽車公司、本田汽車公司、美國的Delphi汽車系統(tǒng)公司、TRW公司及德國的ZF公司都相繼研制出EPS。Mercedes2Benz和SiemensAutomotive兩大公司共同投資6500萬英鎊用于開發(fā)EPS,目標(biāo)是到2002年裝車,年產(chǎn)300萬套,成為全球EPS制造商。到目前為止,EPS系統(tǒng)在輕微型轎車、廂式車上得到廣泛的應(yīng)用,并且每年以300萬臺的速度發(fā)展。轉(zhuǎn)向是一個專業(yè)術(shù)語,適用于采集部件,聯(lián)系等,其中允許一艘(艦船)或汽車(轎車)按照預(yù)期的方向行駛.一個例外的情況是鐵路運(yùn)輸由路軌組合在一起鐵路道岔提供轉(zhuǎn)向功能。許多現(xiàn)代轎車使用齒輪齒條式轉(zhuǎn)向器,在方向盤末端有轉(zhuǎn)動齒輪;該齒輪帶動齒條移動,它是一種線性的齒輪緊密配合,從一邊到一邊。這種運(yùn)動把轉(zhuǎn)矩通過轉(zhuǎn)向橫拉桿和一種叫做轉(zhuǎn)向節(jié)臂的短形臂傳遞給轉(zhuǎn)向輪的主銷。以前的設(shè)計(jì)往往采用循環(huán)球式轉(zhuǎn)向器,而這種轉(zhuǎn)向器仍然應(yīng)用在卡車和多用途車輛。這是一種老式的螺母和齒扇設(shè)計(jì),該轉(zhuǎn)向管柱轉(zhuǎn)動大螺絲(蝸輪),它與一個齒扇齒輪嚙合,當(dāng)蝸輪轉(zhuǎn)動時(shí),齒扇也隨之轉(zhuǎn)動,一個安裝在齒扇軸上且與轉(zhuǎn)向聯(lián)動有關(guān)的搖臂帶動轉(zhuǎn)向節(jié)臂,從而使車輪轉(zhuǎn)動.循環(huán)球式轉(zhuǎn)向器通過安裝滾珠減少螺母和螺桿之間的摩擦;兩根導(dǎo)管和螺母內(nèi)的螺旋管狀通道組合成兩條各自獨(dú)立的封閉的鋼球“流到”。齒輪齒條式轉(zhuǎn)向器設(shè)計(jì)具有很大程度的反饋和直接轉(zhuǎn)向路感;它也通常不會有任何反彈,或呆滯。缺點(diǎn)是,它是不可調(diào)的,因此當(dāng)它磨損唯一的解決辦法更換。循環(huán)球式轉(zhuǎn)向器的優(yōu)點(diǎn)是機(jī)械優(yōu)勢,因此,它被使用在較大較重的車輛,而齒輪齒條式原本僅限于較小和較輕;由于幾乎普遍采用動力轉(zhuǎn)向系統(tǒng),不過,這已不再是一個重要的優(yōu)勢,導(dǎo)致越來越多地在新型汽車應(yīng)用齒輪齒條式轉(zhuǎn)向器。循環(huán)球式轉(zhuǎn)向器設(shè)計(jì)在中心也有明顯的沖擊,或死點(diǎn)。凡一分鐘交替方向盤出不來并不移動轉(zhuǎn)向機(jī)構(gòu);這是很容易可調(diào)螺桿的端部來減少磨損,但它并不能完全消除或機(jī)制開始磨損很快。這項(xiàng)設(shè)計(jì)目前仍在使用中,在卡車和其他大型車輛,也應(yīng)用于迅速轉(zhuǎn)向,路感與穩(wěn)健性,可維護(hù)性,和機(jī)械的優(yōu)勢相比不太重要的場合。較小程度的反饋,這樣的設(shè)計(jì)也有時(shí)是一種優(yōu)點(diǎn);當(dāng)前輪碰撞時(shí),使用齒輪齒條轉(zhuǎn)向的司機(jī)只有自己的大拇指受傷,造成方向盤揭開一邊突然(因?yàn)轳{駛教練告訴學(xué)生把自己的大拇指在前面的方向盤,而非放在左右的內(nèi)邊緣).這種效果在像卡車一樣的重型汽車更為明顯;循環(huán)球式轉(zhuǎn)向防止這種程度的反饋,只是因?yàn)樗梢栽谡G闆r下防止可取反饋。轉(zhuǎn)向連鎖連接轉(zhuǎn)向器和車輪通常符合一個阿克曼轉(zhuǎn)向幾何的變化,它交代了一個事實(shí):當(dāng)轉(zhuǎn)向是,內(nèi)輪轉(zhuǎn)過的半徑比外輪小得多,因此適合駕駛的直路,是不適合曲折。由于車輛已成為較重而改用前輪驅(qū)動,為了扭轉(zhuǎn)方向盤,通常的,主要的是體力。為了解決這一問題,汽車業(yè)發(fā)展的動力轉(zhuǎn)向系統(tǒng)。有兩種類型的助力轉(zhuǎn)向系統(tǒng)-液壓和電氣/電子。還有一種液壓-電動混合系統(tǒng)。液壓助力轉(zhuǎn)向系統(tǒng)(hps)利用油壓供應(yīng)的一個發(fā)動機(jī)驅(qū)動泵,以協(xié)助將方向盤轉(zhuǎn)轉(zhuǎn)動。電動助力轉(zhuǎn)向系統(tǒng)(EPS)方式,是較有效率的液壓助力轉(zhuǎn)向系統(tǒng),由于電動助力轉(zhuǎn)向汽車只需要提供協(xié)助時(shí),方向盤被轉(zhuǎn)動,而液壓泵必須不斷運(yùn)行。在EPS的幫助下是很容易調(diào)節(jié)車型,最高車速,甚至駕駛的喜好。另外一個好處是,通過泄漏和處置動力轉(zhuǎn)向液消除對環(huán)境構(gòu)成危險(xiǎn)。動力轉(zhuǎn)向的分支是速度可調(diào)轉(zhuǎn)向而轉(zhuǎn)向是大量輔助以低速行駛,稍微協(xié)助高速。汽車制造商認(rèn)為,當(dāng)要停車時(shí)駕駛?cè)丝赡苄枰龀龃罅哭D(zhuǎn)向投入,但當(dāng)時(shí)高速行駛時(shí)則不然。第一輛有這特點(diǎn)的汽車,是雪鐵龍與其diravi,雖然改變了現(xiàn)代汽車轉(zhuǎn)向系統(tǒng)資金的投入,但它改變了定心凸輪的壓力,使得方向盤盡力去回到原來的位置?,F(xiàn)代速度可調(diào)式動力轉(zhuǎn)向系統(tǒng),當(dāng)速度增長時(shí)減少了活塞的壓力,給予更直接的感受。這一特點(diǎn)在所有新車正逐漸成為司空見慣。四輪轉(zhuǎn)向(或全輪轉(zhuǎn)向)是一種系統(tǒng),當(dāng)高速行駛時(shí)能增加車輛穩(wěn)定型,而在低速行駛時(shí)可以減小轉(zhuǎn)彎半徑。大多數(shù)的四輪轉(zhuǎn)向系統(tǒng),后輪轉(zhuǎn)向通過單片機(jī)和驅(qū)動器實(shí)現(xiàn)。后輪一般不能反過來,有幾個系統(tǒng),包括Delphi的quadrasteer,該系統(tǒng)在本田的生產(chǎn)前線,當(dāng)前輪低速時(shí),允許后輪在相反方向轉(zhuǎn)向。這使得車輛轉(zhuǎn)彎半徑較小,有時(shí)應(yīng)用于大型卡車車輛及掛車。
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