中英文文献翻译

TruckMainReductionGearInthehighlycompetitiveperiodfollowingtheenergycrisisoftheearly1970s,theautomotiveindustryhadtoshiftattentionincreasinglytowardsimprovementofthequalityoftheproduct,yetstillkeepingitspricesaslowaspossible.PriortothatGKNAxlesLtd,totakeoptimumadvantageofeconomiesofscale,hadbeenproducingathighlycompetitivepricesastandardrangeofaxlesofdifferenttypesandsizes,fromwhichallcustomersneedscouldbesatisfied.Becausevehiclemanufacturershadnothithertohadtoplacesuchagreatemphasisonfueleconomy,andthereforeonlightweight,thesestandardaxlescouldcaterreliablyforallconditionslikelytobemetinawidevarietyofapplications.Nowvehiclemanufacturersrequireaxlesdesignedanddevelopedfortheirspecificapplications.Asaxledesignisbecomingincreasinglyspecialised,customersareincreasinglyraisingtheiraspirationsintermsofperformaneeanreliability.Forthisreason,theyareturningtospecialistssuchasGKNAxlesLtdwhohavetheabilitytoprovideaxlesforawidevarietyofvehicles。Sincethe1970s,however,incommonwithvirtuallyallothersupplierstothehighvolumeproducersinthemotorindustry,GKNhasradicallymodifieditsapproachtosuittheprevailingconditionsastheychangethroughthe1980sandonintothe1990s.Itsaimnowisatsupplyingcompleteaxleassembles,including,forexample,thebrakes,alldesignedandfullydevelopedforandintegrated,asamatterofcourse,intospecificvehicledesignsincluding,inparticular,thoseforthespecialistmarket.Emphasisisnowonrationalizationofmaterials,methodsandcomponents.Thisoverallchangehasbeennecessarybecauseofthegreatlyincreasedsophisticationdemandedofthemodernvehicle,intermsofoverallefficiency,compactness,lightweight,reliability,durability,refinementandmaintenance-freeoperation.AnotherareaintowhichGKNAxleshasexpandedisthesupplyofcomponentsandassembliessuchaslimited-slipdifferentials,ball-joints,transferboxes,gearsandsometypesofsuspension.Foroff-roadoperation,thedutycyclesmaybeentirelydifferentinbothtorsionalandbeamloading-denpendingontheapplication.Forexample,sometypesofvehiclespendaconsiderableproportionoftheirrunningtimeathightorqueinlowgear.Inmostcircumstances,theterrainmaybesuchthatthetyrestendtoslipmorereadilythanontarmac;inothers,however,forexampleinfairlyfirmsandyscrees,itmayallowtyrestobiteintoit,andthusleadtotorsionalfatigueloadingsignificantlygreaterthanonsmoothroads.Verticalandlateralloading,too,maybemuchmoresevere,thoughthisdosedependtoamajorextentonspeeds.Shockloadingcanalsoaffectbrakingandaccelerationtorquesthough,again,sucheffectsarespeed-dependent.Hypoidgearsystemsaremorecommonlyusedthanspiralbevels.Theirprincipleadvantagesarethatpinionsofaspecificratioarebigger,theirteethprofilesareoflargeradius,theyareinherentlystrongerandmoredurable,theirmeshingareasarelarger,andtheygeneratelessnoiseHostreductiongeareffectistobeusedtoreducetherotationratethatthetransmissionshaftsendsinbuttoenhancerevolutionmomentoftorsion,changesdrivedirectionwithmomentoftorsion,passesontohalfaxesafterdifferentialmechanismand.Thehostreductiongearstructureformisthattheformisdifferentbutdifferentaccordingtogearwheeltype,reductiongearmainly.Hostreductiongeargearwheelhashelixconeformssuchasgearwheel,hypoidgear,columngearwheelandwormgearwormmainly.Pairoflevelhostreductiongeariscomparedwithsinglestage,thegapmaybe712transmissionratio,ioeachotheratthesametimeinsweartobeawayfromafield12.Butthedimension,massarewithoutexceptionbigger,costishigher.Itappliestomiddle,heavytypefreighttrain,go-anywherevehicleandmotorbusmainlygoahead.Dyadicoverallpairoflevelhostreductiongearhasthevariousstructurescheme:Firstorderisaconegearwheel,thesecondstageisacolumngearwheel;Firstorderisaconegearwheel,thesecondstageisepicyclicgear;Firstorderisepicyclicgear,thesecondstageisaconegearwheel;Firstorderisacolumngearwheel,thesecondstageisaconegearwheel.Horizontal,askew,faceanddroopovertothethreekindstofirstorderfortheconegearwheel,thesecondstagearethatpairofcolumngearwheellevelbetokensreductiongear,buthasdirectionarrangementscheme.Directionlevelarrangementcanusetheassemblydroopingovertooutlinedimensiondiminution,reducingtheautomobilequalityheartaltitudethereby,makesthedirectiondimensionincreasebybut,thattheuseonlongdistaneebetweenshaftsautomobilebutappropriatediminutiontransmissionshaftlength,isharmfulforshortdistaneebetweenshaftsautomobilestoputarrangementtogetherbut,maymakeatransmissionshaftshort,leadstoauniversaltransmissionshaftintersectionangleenlarge.Droopovertoarrangingamessengertodrivethebridgedirectiondimensiondiminution,maydiminishauniversaltransmissionshaftintersectionangle,sincebuthostreductiongearshellfixessuperjacentinbridgeshell,makenotonlydroopoverenhancetooutlinedimension,andhavereducedbridgeshellstiffness,havebeenharmfulforgearwheeltowork.Thisarrangementbuteasytobeversedinstyledrivingabridgearrangement.Arrangingbridgeshellstiffnessandimprovingtothetransmissionshaftisslantingtoarrangementadvantageous.Whenassigningatransmissionratioinpairoflevelhostreductiongearhavingtheconegearwheelandthecolumngearwheel,thecolumngearwheelis1.4liketheratioauxiliaryandboringsubsidiarygearwheeltransmissionratio2.0,andtheconegearwheelis1.7likesubsidiarytransmissionratio3.3,suchaxialloadingmaydiminishaconewhenthegearwheelisengagedandeffectloadingonthedrivenconegearwheelandthecolumngearwheel,maymaketheactiveconegearwheeltoothnumberappropriateincreasingbyatthesametime,makewhosesupportingaxisneckdimensionappropriateenlarge,Toimprovewhosesupportingstiffness,improvefalling-instationarityandthejobreliability.Formodernaxles,choiceofgearlubricantcanbecritical.Incarsoperatingathighspeedsonmotorways,axleoiltemperaturecanultimatelyriseevenhigherthan130C,soventingofthecasingisimportant.Inprinciple,theoilinthebaseofthecastingissweptaroundoverthecrownwheelandthenforwardsthroughthetwobearingsthatcarrythepinion.Consequently,boththeshapesanddimensionsoftheclearancesbetweenthecrownwheelandcasingcanbecritical,andadequatedrainagehastobeprovidedfortheoiltoflow,throughchannelscoredinthepinionbearinghousings,backtothebaseofthecasing.Withinthegearcarrierunit,taperrollerbearingsareemployedalmostuniversallyforcarryingtheinputpinion.Theyhavealargeloadcapacitywithinasmallenvelope,andcanbepreloadedforaccurateandstablepositioningofthegears.Forpinionflangesealswhereresistancetohightemperaturesatrelativelyhighspeedsisessential,polyarcylatemaybespecified,buttheabrasiveconditionsVitonisgenerallypreferred.Thattheconegearwheeltoothgoesoverwidthfacetofacecannotenhancegearwheelintensityandlife-span,isabletoleadtotoothditchunexpectedturnofeventssmallendbecauseofconegearwheelgearteethonthecontrarynarrowthecuttingknifethetopoftheheadfacewidtharousingistoonarrowandthepointofakniferoundangleistoosmall.Likethis,notonly,havediminishedthetoothradicalcircleradius,haveenlargedstrainalltogether,lifetimehavingreducedacutter.Besides,whenassembling,havelocationdeviationorwaitforcausesincefabrication,heattreatmentaredeformable,loadingconcentratesminoringearteethendwhenmakingagearwheelwork,isabletoarousegearteethholdinguntimelydamageandwearylossforashorttime.Thatbesides,thetoothgoesoverwidthfacetofacealsoisabletoarouseassemblingspacediminution.Theflankofatoothistoonarrowbut,thegearteethoutsideabrasionresistaneemeetingreduces.Fortherunning-inimprovingthenewgearwheel,preventthepersonfromdyinginworkingtoModelTwearappearoninitialstage,bruising,gluingtogetherorbarking,conegearwheelbonderizingbeing0.0050.020mminheattreatmentandfinishmachiningaftercrop,thicknesshandlesorthecopperfacing,thetinplatinghandle.Theballcarryingoutstrainontheflankofatoothgushingissoldatreducedprices,mayimprove25%sgearwheellife-span.Tothehighspeedgearwheelsliding,maybeinprogressasulfuroozinghandlingtoimproveabrasionresistanee.Rubafactorbutnotablesulfurqueenlesseningoozes,eveniflubricatingconditionisrelativelypoor,also,canpreventtheflankofatoothbruisefromfacing,barkstodieandgluetogether.重型卡车主减速器在能源竞争激烈的二十世纪七十年代初，汽车业不得不将注意力越来越多地定格在改进产品的质量上，但仍然维持其价格尽可能低。在此之前，吉凯恩车桥有限公司占据最佳经济规模的优势，在价格允许范围内生产极具竞争力的不同类型车轴，使所有客户的需求可以得到满足。但由于汽车制造商并没有经历过这样一个非常注重燃油经济性的时期，因此，对重量轻的要求，这些标准车轴似乎可满足所有条件，满足各种各样的应用。现在汽车制造商需要车轴设计和开发的具体应用。轴设计正变得越来越专业化，在性能的可靠性方面，客户越来越多地提高自己的期望。出于这个原因，他们在找一个能提供各种车辆轴的公司。然而自二十世纪七十年代以来，在几乎所有其他汽车行业供应商的技术里，GKN从根本上改变了它的办法，以适应当前的条件，他们在二十世纪八十年代和九十年代的生产目的是提供完整的轮轴安装，其中包括，刹车、所有的设计和整合、具体的汽车设计，以及为专业市场特别设计的。现在的重点是合理化的材料，方法和内容。总的改革是必要的，对于复杂性很大的现代汽车，考虑总体效率，紧凑，重量轻，可靠性，耐用性，完善和免维护运行。另一个领域，GKN提供的车轴是扩大了供应的部件和组件，如限滑差速器，球关节，齿轮和某些类型的悬挂架。对于越野车，某些车辆设计公司花费了相当多的时间在较低齿轮但高扭矩的设计上。在大多数情况下，地形可能使这样的轮胎打滑。例如，在相当坚硬的沙质路面，它可能允许轮胎咬进去，从而使扭转疲劳显著大于在平稳的道路行驶。虽然在大程度上这取决于速度，但纵向和横向打滑时将更严重。冲击负荷也会影响刹车和加速扭矩，这种影响是取决于速度的。准双曲面齿轮传动是锥齿轮传动中的普遍形式，螺旋锥齿轮是它的一种特殊情况。他们的优点是齿轮的具体比例较大，其啮合区较大，而且低噪音，他们本质上是更强大，更持久和更耐用。主减速器的作用是用来降低传动轴传来的转速而增大旋转扭矩，并将扭矩改变传动方向，经差速器传给半轴。主减速器的结构形式主要是根据齿轮类型、减速器形式不同而不同。主减速器的齿轮主要有螺旋锥齿轮、双曲面齿轮、圆柱齿轮和蜗轮蜗杆等形式。双级主减速器与单级相比，在保证离地间隙相同时可得到大的传动比，io般为712。但是尺寸、质量均较大，成本较高。它主要应用于中、重型货车、越野车和大客车上。整体式双级主减速器有多种结构方案：第一级为锥齿轮，第二级为圆柱齿轮；第一级为锥齿轮，第二级为行星齿轮；第一级为行星齿轮，第二级为锥齿轮；第一级为圆柱齿轮，第二级为锥齿轮。对于第一级为锥齿轮、第二级为圆柱齿轮的双级主减速器，可有纵向水平、斜向和垂向三种布置方案。纵向水平布置可以使总成的垂向轮廓尺寸减小，从而降低汽车的质心高度，但使纵向尺寸增加，用在长轴距汽车上可适当减小传动轴长度，但不利于短轴距汽车的总布置，会使传动轴过短，导致万向传动轴夹角加大。垂向布置使驱动桥纵向尺寸减小，可减小万向传动轴夹角，但由于主减速器壳固定在桥壳的上方，不仅使垂向轮廓尺寸增大，而且降低了桥壳刚度，不利于齿轮工作。这种布置可便于贯通式驱动桥的布置。斜向布置对传动轴布置和提高桥壳刚度有利。在具有锥齿轮和圆柱齿轮的双级主减速器中分配传动比时，圆柱齿轮副和锥齿轮副传动比的比值一般为1.42.0,而且锥齿轮副传动比一般为1.73.3,这样可减小锥齿轮啮合时的轴向载荷和作用在从动锥齿轮及圆柱齿轮上的载荷，同时可使主动锥齿轮的齿数适当增多，使其支承轴颈的尺寸适当加大，以改善其支承刚度，提高啮合平稳性和工作可靠性。现代车桥中，齿轮润滑油的选择是至关重要的。汽车运行在高速公路上，车桥油温可以最终上升，甚至高于130C，所以车桥外壳通风是很重要的。通过两个轴承携带的小齿轮来达到改善的目的。因此，形状和尺寸之间的间隙，套管等可能都是至关重要的，足够的排水必须提供的润滑油的流向，通过渠道流入小齿轮轴承座，再回到套管。在齿轮轴承中，圆锥滚子轴承普遍应用在齿轮。他们有大量的承载能力，通过稳定的、准确定位。法兰密圭寸的齿轮对于抗高温和相对较高的速度是至关重要的。锥齿轮齿面过宽并不能增大齿轮的强度和寿命，反而会导致因锥齿轮轮齿小端齿沟变窄引起的切削刀头顶面宽过窄及刀尖圆角过小。这样，不但减小了齿根圆半径，加大了应力集中，还降低了刀具的使用寿命。此外，在安装时有位置偏差或由于制造、热处理变形等原因，使齿轮工作时载荷集中于轮齿小端，会引起轮齿小端过早损坏和疲劳损伤。另外，齿面过宽也会引起装配空间的减小。但是齿面过窄，轮齿表面的耐磨性会降低。为改善新齿轮的磨合，防止其在运行初期出现早期的磨损、擦伤、胶合或咬死，锥齿轮在热处理及精加工后，作厚度为0.0050.020mm的磷化处理或镀铜、镀锡处理对齿面进行应力喷丸处理，可提高25%的齿轮寿命。对于滑动速度高的齿轮，可进行渗硫处理以提高耐磨性。渗硫后摩擦因数可显著降低，即使润滑条件较差，也能防止齿面擦伤、咬死和胶合。