汽车主减速器外文翻译Word文档格式.docx

汽车主减速器外文翻译Word文档格式.docx

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1.Manufacturersinstallarearaxleratiothatprovidesacompromisebetweenperformanceandeconomy.Theaveragepassengercarratiois3.50:

1.

Thehigheraxleratio,4.11:

1forinstance,wouldincreaseaccelerationandpullingpowerbutwoulddecreasefueleconomy.Theenginewouldhavetorunatahigherrpmtomaintainanequalcruisingspeed.

Theloweraxleratio.3:

1,wouldreduceaccelerationandpullingpowerbutwouldincreasefuelmileage.Theenginewouldrunatalowerrpmwhilemaintainingthesamespeed.

Themajorcomponentsofthefinaldriveincludethepiniongear,connectedtothedriveshaft,andabevelgearorringgearthatisboltedorrivetedtothedifferentialcarrier.Tomaintainaccurateandproperalignmentandtoothcontact,theringgearanddifferentialassemblyaremountedinbearings.Thebeveldrivepinionissupportedbytwotaperedrollerbearings,mountedinthedifferentialcarrier.Thispinionshaftisstraddlemounted.meaningthatabearingislocatedoneachsideofthepinionshaftteeth.Oilsealspreventthelossoflubricantfromthehousingwherethepinionshaftandaxleshaftsprotrude.Asamechanic,youwillencounterthefinaldrivegearsinthespiralbevelandhypoiddesign.

SpiralBevelGear

Spiralbevelgearshavecurvedgearteethwiththepinionandringgearonthesamecenterline.Thistypeoffinaldriveisusedextensivelyintruckandoccasionallyinolderautomobiles.Thisdesignallowsforconstantcontactbetweentheringgearandpinion.Italsonecessitatestheuseofheavygradelubricants.

HypoidGear

Thehypoidgearfinaldriveisanimprovementorvariationofthespiralbeveldesignandiscommonlyusedinlightandmediumtrucksandalldomesticrear-wheeldriveautomobiles.Hypoidgearshavereplacedspiralbevelgearsbecausetheylowerthehumpinthefloorofthevehicleandimprovegear-meshingaction.Asyoucanseeinfigure5-13,thepinionmesheswiththeringgearbelowthecenterlineandisataslightangle（lessthan90degrees）.

Figure5-13.—Typesoffinaldrives.

Thisangleandtheuseofheavier（larger）teethpermitanincreasedamountofpowertobetransmittedwhilethesizeoftheringgearandhousingremainconstant.Thetoothdesignissimilartothespiralbevelbutincludessomeofthecharacteristicsofthewormgear.Thispermitsthereduceddriveangle.Thehypoidgearteethhaveamorepronouncedcurveandsteeperangle,resultinginlargertoothareasandmoreteethtobeincontactatthesametime.Withmorethanonegeartoothincontact,ahypoiddesignincreasesgearlifeandreducesgearnoise.Thewipingactionoftheteethcausesheavytoothpressurethatrequirestheuseofheavygradelubricants.

Double-ReductionFinalDrive

Inthefinaldrivesshowninfigure5-13,thereisasinglefixedgearreduction.Thisistheonlygearreductioninmostautomobilesandlight-andsomemedium-dutytrucksbetweenthedriveshaftandthewheels.

Double-reductionfinaldrivesareusedforheavy-dutytrucks.Withthisarrangement（fig.5-14）itisnotnecessarytohavealargeringgeartogetthenecessarygearreduction.Thefirstgearreductionisobtainedthroughapinionandringgearasthesinglefixedgearreductionfinaldrive.Referringtofigure5-14,noticethatthesecondarypinionismountedontheprimaryringgearshaft.Thesecondgearreductionistheresultofthesecondarypinionwhichisrigidlyattachedtotheprimaryringgear,drivingalargehelicalgearwhichisattachedtothedifferentialcase.Double-reductionfinaldrivesmaybefoundonmilitarydesignvehicles,suchasthe5-tontruck.Manycommerciallydesignedvehiclesofthissizeuseasingle-ordouble-reductionfinaldrivewithprovisionsfortwospeedstobeincorporated

Figure5-14.—Double-reductionfinaldrive

Two-SpeedFinalDrive

Thetwo-speedordual-ratiofinaldriveisusedtosupplementthegearingoftheotherdrivetraincomponentsandisusedinvehicleswithasingledriveaxle（fig.5-15）.Theoperatorcanselecttherangeorspeedofthisaxlewithabuttonontheshiftingleverofthetransmissionorbyaleverthroughlinkage

Thetwo-speedfinaldrivedoublesthenumberofgearratiosavailablefordrivingthevehicleundervariousloadandroadconditions.Forexample,avehiclewithatwo-speedunitandafive-speedtransmission,tendifferentforwardspeedsareavailable.Thisunitprovidesagearratiohighenoughtopermitpullingaheavyloadupsteepgradesandalowratiotopermitthevehicletorunathighspeedswithalightloadornoload

Theconventionalspiralbevelpinionandringgeardrivesthetwo-speedunit,butaplanetarygeartrainisplacedbetweenthedifferentialdriveringgearandthedifferentialcase.Theinternalgearoftheplanetarygeartrainisboltedrigidlytothebeveldrivegear.Aringonwhichtheplanetarygearsarepivotedisboltedtothedifferentialcase.Amember,consistingofthesungearandadogclutch,slidesononeoftheaxleshaftsandiscontrolledthroughabuttonorleveraccessibletotheoperator

Wheninhighrange,thesungearmesheswiththeinternalteethontheringcarryingtheplanetarygearsanddisengagesthedogclutchfromtheleftbearingadjustingring,whichisrigidlyheldinthedifferentialcarrier.Inthisposition,theplanetarygeartrainislockedtogether.Thereisnorelativemotionbetweenthedifferentialcaseandthegearsintheplanetarydrivetrain.Thedifferentialcaseisdrivendirectlybythedifferentialringgear,thesameasintheconventionalsinglefixedgearfinaldrive.

Whenshiftedintolowrange,thesungearisslidoutofmeshwiththeringcarryingtheplanetarygears.Thedogclutchmakesarigidconnectionwiththeleftbearingadjustingring.Becausethesungearisintegralwiththedogclutch,itisalsolockedtothebearingadjustingringsandremainsstationary.Theinternalgearrotatestheplanetarygearsaroundthestationarysungear,andthedifferentialcaseisdrivenbytheringonwhichtheplanetarygearsarepivoted.Thisactionproducesthegearreduction,orlowspeed,oftheaxle

DIFFERENTIALACTION

Therearwheelsofavehicledonotalwaysturnatthesamespeed.Whenthevehicleisturningorwhentirediametersdifferslightly,therearwheelsmustrotateatdifferentspeeds.

Iftherewereasolidconnectionbetweeneachaxleandthedifferentialcase,thetireswouldtendtoslide,squeal,andwearwhenevertheoperatorturnedthesteeringwheelofthevehicle.Adifferentialisdesignedtopreventthisproblem.

DrivingStraightAhead

Whenavehicleisdrivingstraightahead,theringgear,thedifferentialcase,thedifferentialpiniongears,andthedifferentialsidegearsturnasaunit.ThetwodifferentialpiniongearsdoNOTrotateonthepinionshaft,becausetheyexertequalforceonthesidegears.Asaresult,thesidegearsturnatthesamespeedastheringgear,causingbothrearwheelstoturnatthesamespeed.

TurningCorners

Whenthevehiclebeginstoroundacurve,thedifferentialpiniongearsrotateonthepinionshaft.Thisoccursbecausethepiniongearsmustwalkaroundtheslowerturningdifferentialsidegear.Therefore,thepiniongearscarryadditionalrotarymotiontothefasterturningouterwheelontheturn..

Differentialspeedisconsideredtobe100percent.Therotatingactionofthepiniongearscarries90percentofthisspeedtotheslowingmoverinnerwheelandsends110percentofthespeedtothefasterrotatingouterwheel.Thisactionallowsthevehicletomaketheturnwithoutslidingorsquealingthewheels.

Figure5-15.—Twospeedfinaldrive

汽车主减速器

主减速器

主减速器是在传动轴和差速器之间的一个动力传动系统的组成部分。

它的作用是通过90°

传动轴改变传给驱动轴的动力传递方向。

同时，它提供了一个固定的减速，该值介于传动轴和驱动轮轴的速度之间。

主减速器的减速和齿轮传动比取决于环形齿轮齿数和小齿轮齿数。

客车的减速在3:

1到5:

1之间，卡车是在5:

1到11:

1之间。

计算后轴传动比要数每个齿轮上的齿数。

然后把小齿轮的齿数插入环形齿轮的齿数。

例如，如果小齿轮有10齿，齿圈有30（30除以10），后轴比率将3:

1。

生产厂家在安装后轴传动比时要考虑到性能和费用之间的协调。

客车平均的比率是3.50:

1

更高轴比，例如4。

11:

1，将增加加速度和动力但会降低燃油经济性。

发动机将不得不突然进攻一个更高转速保持一个能与之匹敌的速度。

较低级轴比如3:

1，将减少加速度和拉动力但是将会增加燃油里程。

发动机将突然进攻一个降低转速而维持同一速度。

主减速器的主要元件包括连接到传动轴上的小齿轮，和一个被啰嗦或是铆钉固定在差速器壳上的斜齿轮或者是圆柱齿轮。

为了保持轮齿之间准确，正确的接触，齿圈，差动总成被安装在一定的方位。

主动小锥齿轮由二对圆锥滚子轴承支撑，安装在差速器上。

这个小齿轮轴跨式组合安装。

意味着那是一个能被定位在每个小齿轮齿侧的轴齿。

油封是为了防止润滑剂，小齿轮轴，轴凸出的部分泄漏

弧齿锥齿轮

具有弯曲的轮齿的弧齿锥齿轮同小齿轮，齿圈在同一中心线。

这种主减速器形式被广阔使用在卡车上，偶尔用在年长的汽车上。

这个设计允许环形齿和小齿轮之间建立不断地联系。

它也因此有必要用高等级滑润剂。

双曲面齿轮

双曲面齿轮减速器是一个改进或变异的盘旋斜角设计，常用在轻型和中型卡车以及所有国内的四轮驱动汽车上。

双曲面齿轮已经取代了弧齿锥齿轮，因为他们降低了汽车底板上的凸起，改善轮齿啮合行动。

正如你看到的在5-13图中，小齿轮轴线在中心线的下方，在一个轻微角度（少于90°

）。

这个角度和用的重（大）的轮齿可以保证被传递的功率增加同时保持环形齿的大小和容积不变。

这种齿型设计类似盘旋斜角然而包括一些蜗轮的特征。

这个保证驱动器角的减小。

双曲线齿轮轮齿有一个更显著的弯曲和陡峭的角，导致了在大齿轮轮齿地区更多的轮齿在同时接触。

在不止一个轮齿在同时接触的情况下，一个双曲线设计能够增加齿轮的寿命和减少齿轮噪音。

轮齿的纵向滑动会引起很大的压力，所以要使用高等级的润滑油。

双级主减速器

在图5-13所示的主减速器中，有一个独立的固定减速齿轮。

这个独一无二的减速齿轮常用在大多数汽车和轻型和中型卡车的传动轴和车轮之间。

双极主减速器被用在重型卡车上。

有了这种安排（图：

5-14）我们就没必要用一个大直径的环形齿轮来使其获得必要的齿轮减速。

第一级齿轮减速是通过一个小齿轮，齿圈作为单固定齿轮减速来实现的主减速器。

提到图5-14，我们注意