会员注册 | 登录 | 微信快捷登录 QQ登录 微博登录 | 帮助中心 人人文库renrendoc.com美如初恋!
站内搜索 百度文库

热门搜索: 直缝焊接机 矿井提升机 循环球式转向器图纸 机器人手爪发展史 管道机器人dwg 动平衡试验台设计

   首页 人人文库网 > 资源分类 > DOC文档下载

外文翻译--卡车和货车.doc

  • 资源星级:
  • 资源大小:13.06MB   全文页数:26页
  • 资源格式: DOC        下载权限:注册会员/VIP会员
您还没有登陆,请先登录。登陆后即可下载此文档。
  合作网站登录: 微信快捷登录 支付宝快捷登录   QQ登录   微博登录
友情提示
2:本站资源不支持迅雷下载,请使用浏览器直接下载(不支持QQ浏览器)
3:本站资源下载后的文档和图纸-无水印,预览文档经过压缩,下载后原文更清晰   

外文翻译--卡车和货车.doc

附录1英文原文TrucksandWagons3.1GeneralTrucksarehaulingunitswhich,becauseoftheirhighspeedswhenoperatingonsuitableroads,havehighcapacitiesandproviderelativelylowhaulingcosts.Theyprovideahighdegreeofflexibility,asthenumberinservicemaybeincreasedordecreasedeasilytopermitmodificationsinthetotalhaulingcapacityofafleet.Mosttrucksmaybeoperatedoveranyhaulroadforwhichthesurfaceissufficientlyfirmandsmoothandonwhichthegradesarenotexcessivelysteep.Someunitsnowinusearedesignatedasoffhighwaytrucksbecausetheirsizesandtotalloadsarelargerthanthatarepermittedonhighways.Thesetrucksareusedforhaulingmaterialsonlargeprojects,wherethesizesandcostsarejustified.Trucksmaybeclassifiedaccordingtoagreatmanyfactors,includingthefollowing1.Sizeandtypeofenginegasoline,diesel,butane,propane.2.Numberofgears.3.Kindofdrivetwowheel,fourwheel,sixwheel,etc.4.Numberofwheelsandaxlesandarrangementofdrivingwheels.5.Methodofdumpingtheloadreardump,sidedump.6.classofmaterialhauledearth,rock,coal,ore,etc.7.Capacity,intonorcubicmetercubicyards.8.Methodofdumpingtheloadforreardumps,hydraulicorcable.Iftruckaretobepurchasedforgeneralmaterialhauling,thepurchasershouldselectunitsthatareadaptabletothepurposesforwhichtheywillbeused.However,iftruckaretobeusedonagivenprojectforagivenpurpose,thepurchasershouldselecttrucksthatmostnearlyfittherequirementoftheproject.1.RearDumpTrucks2.Reardumptrucksaresuitableforuseinhaulingmanytypesofmaterials.Theshapeofthebody,suchastheextentofsharpangles,corners,andthecontouroftherear,throughwhichthematerialsmustflowduringdumping,willaffecttheeaseordifficultyofdumpingj41.Thebodiesoftruckthatwillbeusedtohaulwetclayandsimilarmaterialsshouldbefreeofsharpanglesandcorners.Drysandandgravelwillfloweasilyfromalmostanyshapeofbody.Ifquarryrockistobehauled,bodiesshouldbeshallowwithslopingsideboards.2.BottomDumpWagonsIfunitsaretobeusedtohaulmaterials,suchassand,gravel,reasonabledryearth,coal,etc.whichfloweasily,theuseofbottomdumpwagonswillreducethetimerequiredtounloadtheunits.Suchunitsareparticularlysuitableforusewherethematerialsaredistributedinlayersonafilloraredischargedthroughgrizzliesintohoppers.Whendischargingtheloadontofills,thewagonscandumptheirloadswhilemoving.Whendischargingthroughgrizzlies,theywillneedtostopforonlyafewseconds.Therapidrateofdischargingtheloadgivesthesewagonsatimeadvantageoverreardumptrucks.Asthedoorsthroughwhichtheseunitsdischargetheirloadhavelimitedopenings,difficultiesmaybeexperiencedindischargingsuchmaterialsaswet,stickyclay,especiallyiftheyareinlargelumps.Thesewagonsaresatisfactoryhaulingunitsonprojectssuchasearthendams,levees,highwaysandairports,wherelargequantitiesofmaterialsaretobetransportedandhaulroadscanbekeptinreasonablygoodcondition.Theymaybeloadedbypowershovels,draglines,orportablebeltloaders.3.CapacitiesofTrucksandWagonsThereareatleastthreemethodsofexpressingthecapacitiesoftrucksandwagonsbytheloadwhichitwillcarry,expressedintonsbyitsstruckvolumeandbyitsheapedvolume。thelattertwoexpressedincubicmeterorcubicyards.Thestruckcapacityofatruckisthevolumeofmaterialwhichitwillhaulwhenitisfilledtothetopofthesides,withnomaterialabovethesides.Theheapedcapacityisthevolumeofmaterialwhichitwillhaulwhentheloadisheapedabovethesides.Thecapacityshouldbeexpressedincubicmeters.Whilethetruckcapacityremainsfixedforanygivenunit,buttheheapedcapacitywillvarywiththeheighttowhichthematerialmayextendabovethesidesandwiththelengthandwidthofthebody.Wetearthorsandyclaymaybehauledwithaslopeof11,whiledrysandorgravelmaynotpermitaslopegreaterthan31.Inordertodeterminetheprobableheapedcapacityofaunit,itisnecessarytoknowthestruckcapacity,thelengthandwidthofthebody,andtheslopeatwhichthematerialwillremainstablewhiletheunitismoving.Smoothhaulroadswillpermitalargeheapedcapacitythanroughhaulroads.Becauseofvariationsintheheapingcapacitiesofunitsitmaybebettertocomparethemonthebasisoftheirstruckcapacities.Inaneeventthecapacitiesshouldbedeterminedorcomparedinarealisticmanner.Theweightcapacitymaylimitthevolumeoftheloadwhenaunitisusedtohaulheavymaterial,suchasironore.However,whenthespecificgravityofthematerialissuchthatthesafeloadisnotexceeded,aunitmaybefilledtoitsheapedcapacity.Insomeinstancesitispossibletoaddsideboardstoincreasethedepthofthebodyofatruckorwagon,therebypermittingittohaulalargerload.Thispracticeprobablywillincreasethehourlycostofoperatingaunit,becauseofhigherfuelconsumption,reducedtirelife.morefrequentfailuresofparts,suchasaxles,gears,brakes,andclutches,andhighermaintenancecosts.However,ifthevalueoftheextramaterialhauledisgreaterthanthetotalincreaseinthecostofoperatingavehicle,theoverloadingisjustified.Inconsideringhaulinglargervolumesofmaterials,themaximumsafeloadsonthetiresshouldbecheckedtopreventexcessiveoverloading,whichmightresultinconsiderablelosttimeduetotirefailures.3.2DesignandPrincipalMechanismsofTracksTheprincipalmechanismsofmostmoderntruckshaveaverysimilardesignandlayout.Eachtruckconsistsessentiallyofthreecomponentpartsengine,chassisandbody.Trucksarepoweredmainlybycarburetorordieselengines.Thebodyisintendedtocarryloadorpeople.Thedriverscabisusuallyseparatedfromthebody,anditsformanddesignconformtothepurposethetruckistoserve.Thechassiscarriestheengine,body,transmission.runninggearandcontrols.Thepowertrainofatruckisacombinationofmechanismsfortransmittingthetorquedevelopedbytheenginecrankshafttothedrivingwheels.ThepowertrainofamassproducedtruckFig.31incorporatesthefollowingmainmechanisms,thepurposeanddesignofmostofwhichdonotdifferinprinciplefromthecorrespondingmechanismsintractorsengine1,clutch2,transmissionbox3,universaljointshaft4,finaldrive8withdifferential5anddrivingwheels6withaxleshafts7.Whentheresistancemetbythetruckincreases,forexampleinclimbinguphill,thetransmissionboxisusedtoincreasethetorqueattheexpenseofalowerspeed6j.Thetransmissionboxesoftrucksandtractorsaredesignedsimilarlyandthefunctionsperformedbytheengineclutcharethesame.Theuniversaljointshafttransmitstorquefromthetransmissionboxtothefinaldrive.Thetransmissionboxisattachedrigidlytothetruckframe,whilethefinaldriveandtherearaxleareconnectedtotheframebymeansofspring.Asthetyresofthetruckhitbumpsintheroadtherearaxleoscillatescontinuously,changingtheanglebetweenthetransmissionboxandfinaldriveshafts.Forthisreason,themainpurposeoftheuniversaljointshaftisthetransmissionoftorquebetweenshaftincludedatdifferentangles.Thefinaldriveamplifiesthetorqueandtransmitsitfromthelongitudinaluniversaljointshafttothedrivingaxleshaftsandthewheels.Thefinaldrivesintrucksandtractorsservethesamepurpose.Thedifferentialusedintruckfinaldrivesallowsthedrivingwheelstorotateatdifferentspeeds,whichisnecessarywhenthetruckturnsorgoesoverunevenroadandtherightandleftwheelstraveldifferentdistancesduringthesametime.InatruckmovingstraightonasmoothroadthismayOccurwhentheradiioftherightandleftwheelsareunequal.Phenomenoniscausedbyanunequalpressureinthetyres,nonuniformwearofthetyresordifferentloadactingonthewheels.Therunninggearofatruckcomprisesaframesupportingthebodyandallothermechanisms,aswellasthefrontandrearaxles.springsforanelasticsuspensionoftheaxlestotheframe,andairtyredwheels.Thespringsandtyrestransmitloadfromtheframetotheroad,andatthesametimedampjerksandshockswhenthetruckhitsbumpsintheroad.Theresultantoscillationsaredampedbyspecialshockabsorbers.Thesteeringcontrolincludessteeringgear,brakesystem,enginecontrolandpowertraincontro1.Thesteeringgearisusedtochangethedirectionofmotionbyturningthewheels.Whicharelinkedwiththesteeringwheelbyasystemofleversandrods.Thebrakesystemcontributestowardssafetyandslowsdownatruckgoingdownaslope.Thebrakesaremountedonthetruckwheelsandsometimesontheuniversaljointshaft.Thebrakesareconnectedwiththebrakepedalorleverbymeansofmechanical,hydraulicorairoperateddevices.Enginecontrolallowsachangeinthenumberofrevolutionstobeeffectedinaccordancewiththedemands,whilethepowertraincontrolboilsdowntoengaginganddisengagingtheclutchandchangingspeeds.Effortstoimprovethepropertiesoftrucksoradaptthemforspecialpurposescontinuouslychangeandimproveboththeindividualelementsandthegenerallayout.Forallthat,anddespitethegreatdiversityoftypes,alltrucksconsistessentiallyofthemainelementsdescribedabove.3.3PowerTrainofTrucks1、ClutchInconformitywithitsfunction,theclutchshouldsmoothlyengageandjustassmoothlyandrapidlycomeoutofengagement.Drydiskclutchesaremostwidespread.Thedesignoftheclutchpressureassemblysubdividesallclutchesintospringloadedandovercentreclutches.Intheformertypethepressuredisksareconstantlycompressedbyspringsandtheclutchcanbedisengagedbydepressingthepedalwhich,overcomingthespringtension,willdrawapartthefrictionsurfaces.Assoonasthepedalisreleasedthediskswillbeagainbroughtincontactbythesprings.Inthelattertypethedrivinganddrivendisksarepressedtogetherbyalevermechanismandtheclutchleverorpedalneednotbeconstantlydepresse.Effortisappliedtotheleveronlyduringengagementordisengagement.Theseclutchesareemployedmainlyingeneralpurposecrawleragriculturaltractorswhereshorttimestoppagesareaffectedbydisengagingtheclutch,becausethetransmissiongearcannotbechangedwhilerunningandaresomewhatdifficulttoengageanddisengageinviewoftheirlargesize.Springloadedclutchesareusedpredominantlyintrucks.Fig.32illustratesoneofthemostwidespreadandsimpletypesofsinglediskspringloadedclutch.Clutchshaft13transmissionboxdrivingshaftismountedintwoballbearings,itsfrontendrestingintheflywheelopeningandtherearendinthefrontwallofthetransmissionbox.Housing3isattachedtoengineflywheel1.Thepressureondrivendisk2fittedontothesplintedportionofshaft13isprovidedbysprings5installedbetweenthehousingandpressuredrivingdisk4.Threereleaselevers11aremountedonspindles12attachedtohousing3.Thepressuredisk,rotatingtogetherwiththehousingandflywheel,canbeshiftedtoeithersideofthedrivendisktoincreasetheforceoffrictionbetweenthedrivinganddrivendisks.Theclutchreleasemechanismoperatesasfollows.Whensleeve10movestowardstheflywheel,thrustbearing6pressesagainsttheendsofthereleaselevers11whichtherebyturnontheiraxlesandseparatethepressuredrivingdiskfromtheflywheel,releasingthedrivendiskfromtheactionofthespring.Thesleeveisshiftedbyfork9,connectedwithpedal7throughasystemofarmsandrods.Whenthepedalisreleased,sleeve10returnstoitsinitialpositionandthepressurediskisshiftedbythespringstowardstheflywheel.Althoughfrictionclutchesofthistypereduceimpactloadswhenthegearsarebeingchangedinthetransmissionbox,frequentengagementandcontinuousslippingtendtoheatthemexcessively.Insometrucksthepowertrainincorporatesaturboclutch,wherethehydrodynamiceffectofcirculatingfluidisutilizedtotransmittorque.Thispreventstheclutchfromheatingandwearingasaresultofcontinuousslippingandmakesitpossibletoreducethenumberofswitchingoveroperationsinthetransmissionbox.

注意事项

本文(外文翻译--卡车和货车.doc)为本站会员(英文资料库)主动上传,人人文库网仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对上载内容本身不做任何修改或编辑。 若此文所含内容侵犯了您的版权或隐私,请立即通知人人文库网([email protected]),我们立即给予删除!

温馨提示:如果因为网速或其他原因下载失败请重新下载,重复下载不扣分。

copyright@ 2015-2017 人人文库网网站版权所有
苏ICP备12009002号-5