会员注册 | 登录 | 微信快捷登录 支付宝快捷登录 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--内燃机.doc

  • 资源星级:
  • 资源大小:52.50KB   全文页数:9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--内燃机.doc

英文原文ConnectingrodInareciprocatingpistonengine,theconnectingrodorconrodconnectsthepistontothecrankorcrankshaft.Theconnectingrodwasinventedsometimebetween1174and1200whenaMusliminventor,engineerandcraftsmannamedalJazaribuiltfivemachinestopumpwaterforthekingsoftheTurkishArtuqiddynastyoneofwhichincorporatedtheconnectingrod.Transferringrotarymotiontoreciprocatingmotionwasmadepossiblebyconnectingthecrankshafttotheconnectingrod,whichwasdescribedintheBookofKnowledgeofIngeniousMechanicalDevices.Thedoubleactingreciprocatingpistonpumpwasthefirstmachinetoofferautomaticmotion,butitsmechanismsandotherssuchasthecam,wouldalsohelpinitiatetheIndustrialRevolution.InternalcombustionenginesInmodernautomotiveinternalcombustionengines,theconnectingrodsaremostusuallymadeofsteelforproductionengines,butcanbemadeofaluminiumforlightnessandtheabilitytoabsorbhighimpactattheexpenseofdurabilityortitaniumforacombinationofstrengthandlightnessattheexpenseofaffordabilityforhighperformanceengines,orofcastironforapplicationssuchasmotorscooters.Theyarenotrigidlyfixedateitherend,sothattheanglebetweentheconnectingrodandthepistoncanchangeastherodmovesupanddownandrotatesaroundthecrankshaft.Thesmallendattachestothepistonpin,gudgeonpintheusualBritishtermorwristpin,whichiscurrentlymostoftenpressfitintotheconrodbutcanswivelinthepiston,afloatingwristpindesign.Thebigendconnectstothebearingjournalonthecrankthrow,runningonreplaceablebearingshellsaccessibleviatheconrodboltswhichholdthebearingcapontothebigendtypicallythereisapinholeboredthroughthebearingandthebigendoftheconrodsothatpressurizedlubricatingmotoroilsquirtsoutontothethrustsideofthecylinderwalltolubricatethetravelofthepistonsandpistonrings.Theconrodisundertremendousstressfromthereciprocatingloadrepresentedbythepiston,actuallystretchingandrelaxingwitheveryrotation,andtheloadincreasesrapidlywithincreasingenginespeed.Failureofaconnectingrod,usuallycalledthrowingarodisoneofthemostcommoncausesofcatastrophicenginefailureincars,frequentlyputtingthebrokenrodthroughthesideofthecrankcaseandtherebyrenderingtheengineirreparableitcanresultfromfatiguenearaphysicaldefectintherod,lubricationfailureinabearingduetofaultymaintenance,orfromfailureoftherodboltsfromadefect,impropertightening,orreuseofalreadyusedstressedboltswherenotrecommended.Despitetheirfrequentoccurrenceontelevisedcompetitiveautomobileevents,suchfailuresarequiterareonproductioncarsduringnormaldailydriving.Thisisbecauseproductionautopartshaveamuchlargerfactorofsafety,andoftenmoresystematicqualitycontrol.Whenbuildingahighperformanceengine,greatattentionispaidtotheconrods,eliminatingstressrisersbysuchtechniquesasgrindingtheedgesoftherodtoasmoothradius,shotpeeningtoinducecompressivesurfacestressestopreventcrackinitiation,balancingallconrod/pistonassembliestothesameweightandMagnafluxingtorevealotherwiseinvisiblesmallcrackswhichwouldcausetherodtofailunderstress.Inaddition,greatcareistakentotorquetheconrodboltstotheexactvaluespecifiedoftentheseboltsmustbereplacedratherthanreused.Thebigendoftherodisfabricatedasaunitandcutorcrackedintwotoestablishprecisionfitaroundthebigendbearingshell.Therefore,thebigendcapsarenotinterchangeablebetweenconrods,andwhenrebuildinganengine,caremustbetakentoensurethatthecapsofthedifferentconrodsarenotmixedup.Boththeconrodanditsbearingcapareusuallyembossedwiththecorrespondingpositionnumberintheengineblock.RecentenginessuchastheFord4.6literengineandtheChrysler2.0literengine,haveconnectingrodsmadeusingpowdermetallurgy,whichallowsmoreprecisecontrolofsizeandweightwithlessmachiningandlessexcessmasstobemachinedoffforbalancing.Thecapisthenseparatedfromtherodbyafracturingprocess,whichresultsinanunevenmatingsurfaceduetothegrainofthepowderedmetal.Thisensuresthatuponreassembly,thecapwillbeperfectlypositionedwithrespecttotherod,comparedtotheminormisalignmentswhichcanoccurifthematingsurfacesarebothflat.Amajorsourceofenginewearisthesidewaysforceexertedonthepistonthroughtheconrodbythecrankshaft,whichtypicallywearsthecylinderintoanovalcrosssectionratherthancircular,makingitimpossibleforpistonringstocorrectlysealagainstthecylinderwalls.Geometrically,itcanbeseenthatlongerconrodswillreducetheamountofthissidewaysforce,andthereforeleadtolongerenginelife.However,foragivenengineblock,thesumofthelengthoftheconrodplusthepistonstrokeisafixednumber,determinedbythefixeddistancebetweenthecrankshaftaxisandthetopofthecylinderblockwherethecylinderheadfastensthus,foragivencylinderblocklongerstroke,givinggreaterenginedisplacementandpower,requiresashorterconnectingrodorapistonwithsmallercompressionheight,resultinginacceleratedcylinderwear.CompoundrodsManycylindermultibankenginessuchasaV12layouthavelittlespaceavailableforthatmanyconnectingrodjournalsonalimitedlengthofcrankshaft.Thisisadifficultcompromisetosolveanditsconsequencehasoftenledtoenginesbeingregardedasfailures.Thesimplestsolution,almostuniversalinroadcarengines,istousesimplerods.Thisrequirestherodbearingstobenarrower,increasingbearingloadandtheriskoffailureinahighperformanceengine.Thisalsomeanstheopposingcylindersarenotexactlyinlinewitheachother.Incertaintypesofengine,themasterrodcarriesoneormoreringpinstowhichareboltedthemuchsmallerbigendsofslaverodsonothercylinders.Radialenginestypicallyhaveamasterrodforonecylinderandslaverodsforalltheothercylindersinthesamebank.CertaindesignsofVenginesuseamaster/slaverodforeachpairofoppositecylinders.Adrawbackofthisisthatthestrokeofthesubsidiaryrodisslightlyshorterthanthemaster,whichincreasesvibrationinaveeengine.Theusualsolutionforhighperformanceaeroenginesisaforkedconnectingrod.Onerodissplitintwoatthebigendandtheotheristhinnedtofitintothisfork.Thejournalisstillsharedbetweencylinders.TheRollsRoyceMerlinusedthisstyle.CranklinkageofthetypeandcharacteristicsTheuseoftheinternalcombustionenginecranklinkageofmanytypes,accordingtokinematicsperspectivecanbedividedintothreecategories,namelyHeartcranklinkage,theeccentriccranklinkageandthemainvicelinkcranklinkage.Centrecranklinkageischaracterizedbythecylinderthroughthecenterlineofthecrankshaftrotationcentreandperpendiculartotheaxisofrotationofthecrank.Thistypeoflinkageintheinternalcombustionenginecrankinthemostwidelyused.Thesingleenginegeneral,tiedforlinkagewiththeuseoftheVshapedchaxinglinktheinternalcombustionengine,andthehomeofthepistoninternalcombustionenginecranklinkagefallintothiscategory.Eccentriccranklinkageischaracterizedbyverticalcylindercenterlineofthecrankshaftrotatinginthecenter,butnotbycrankshaftrotarycentre,thecylindercenterlinedistancebetweenthecrankshaftwitharotaryaxisoffsete.Thiscranklinkageinstitutionscanreducetheswellingintheitineraryofthepistonandcylinderintramurallargestlateralpressuresothatthepistonsintheexpansionprogrammeandpressurereductionprogrammeinthecylinderwallattheroleoflateralpressureonbothsidesoftherelativelyuniformsize.Vicelinkthemaincranklinkageischaracterizedbytheinternalcombustionenginecylinderwithamainlink,theotheroutvicelinkcylinderused,thesearenotdirectlinktothebottomofthecrankpins,butonsalethroughthedeputylinkwithinthemainlinkofthebigheads,formedajointmovement,suchinstitutionsalsosometimesreferredtoasjointsongstalklinkage.Cranklinkageinthejoint,acrankcanputafewofconnectingrodandpiston,Thisstructurewillshortenthelengthoftheinternalcombustionengine,compactandwidelyusedinhighpowerlocomotivesusedtanksandVshapedinternalcombustionengine.BoringInmachining,boringistheprocessofenlargingaholethathasalreadybeendrilledorcast,bymeansofasinglepointcuttingtoolorofaboringheadcontainingseveralsuchtools,forexampleasinboringacannonbarrel.Boringisusedtoachievegreateraccuracyofthediameterofahole,andcanbeusedtocutataperedhole.Thetermboringisalsosometimesusedfordrillingahole.MachineBoringTheboringprocesscanbecarriedoutonalatheforsmalleroperations,butforlargerproductionpiecesaspecialboringmillworkpiecerotationaroundaverticalaxisorahorizontalboringmachinerotationaroundhorizontalaxisareused.Ataperedholecanalsobemadebyswivelingthehead.TheboringmachinessimilartothemillingmachinessuchastheclassicVanNormancomeinalargevarietyofsizesandstyles.Workpiecediametersarecommonly14m312ftbutcanbeaslargeas20m60ft.Powerrequirementscanbeasmuchas200hp.Thecontrolsystemscanbecomputerbased,allowingforautomationandincreasedconsistency.Becauseboringismeanttodecreasetheproducttolerancesonpreexistingholes,severaldesignconsiderationsmustbemade.First,largelengthtoborediametersarenotpreferredduetocuttingtooldeflection.Next,throughholesarepreferredoverblindholesholesthatdonottraversethethicknessoftheworkpiece.Interruptedinternalworkingsurfaceswherethecuttingtoolandsurfacehavediscontinuouscontactshouldbeavoided.Theboringbaristheprotrudingarmofthemachinethatholdscuttingtools,andmustbeveryrigid.ForgingForgingisthetermforshapingmetalbyusinglocalizedcompressiveforces.Coldforgingisdoneatroomtemperatureornearroomtemperature.Hotforgingisdoneatahightemperature,whichmakesmetaleasiertoshapeandlesslikelytofracture.Warmforgingisdoneatintermediatetemperaturebetweenroomtemperatureandhotforgingtemperatures.Forgedpartscanrangeinweightfromlessthanakilogramto170metrictons.Forgedpartsusuallyrequirefurtherprocessingtoachieveafinishedpart.TheselectionofbaseandpositioningThebasepositionisprotocolmachiningline,determinetheprocessingplanoftheimportantworktodofirstMake.Choosecorrectly,theyankeeswilldirectlyinfluencethereasonableornot,themachiningofqualityandproductivity.Whenselectingpositionintheplane,needtoconsiderthefollowingquestions1inwhichasurfaceastheessenceandsurfaceorunifiedstandards,2toensuremachiningprecision,3Makethemachiningprocesssmoothly4forprocessingthepureplaneorunity,5shouldbeadoptedasaroughsurfaceplane6whetherindividualprocessesforspecialprocessingrequirements,7needtoemployunifiedstandardsofplaneoutsideAccordingtotheessenceandtheyankeeschoicefine,fineandselectionprinciplesshouldbeconsideredwhenthefirst,thebenchmarkoverlapInmay,namely,underthesituationofthemachinedsurfaceshouldbechosenforthelocatingdatumdesignstandards.Intheprocessofconnectingthemachiningprocess,mostofaspecifiedprocessselectionofendandsmallheadholeAsthemainbase,withbigholeinthesideoutsidethedesignatedasanotherroundfaceincludessurface.Thisisduetotheface.Largearea,morestable,Withlittleheadpositioncandirectlycontrolsizeholeholecenterdistanceofthehead.ItmakesTheprocessoflocatingdatum,reducepositioningerror.Furtherstudyagain,Accordingtothedrawing,thesizeoftheconnectingpartshaveaheadholesurfacenamelytherightendinaflatsurface,Therefore,butcanalsobeprocessedanotherendleftisnotanend,fortheplaneasItisdisadvantageouspositiondatum.Therefore,intheprocessofthelocalizationplantoidea.Astheyankeesroundholesmallhead,solittleheadoutsidesurfaceprocessingroundholearrangementearly.InsmallheadandlargeBeforetheyankeesheadholeasorientationofthemachiningprocessesanddrilling,reaming,theseproceduresforprocessingaftertheholeTheholeisparallelwiththatsometimesaffectstheprocessingprecisionfollowupprocesses,therefore,shouldbeinprocessingNotethatchoosesreas

注意事项

本文(外文翻译--内燃机.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