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 > PDF文档下载

外文翻译--发动机轴承设计的发展 英文版.pdf

  • 资源星级:
  • 资源大小:2.47MB   全文页数:18页
  • 资源格式: PDF        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--发动机轴承设计的发展 英文版.pdf

DevelopmentsinenginebearingdesignF.A.MartinSomeoftheimportantrecentdevelopmentsinenginebearingdesigntechniquesarehighlighted.Theavailabilityofincreasedcomputingpowerhasenabledmorerealisticassumptionsaboutbearingconditionstobeconsideredtheseincludeoilfeedfeatures,oilfilmhistory,noncircularbearings,inertiaeffectsduetojournalcentremovement,improvedpredictionofmainbearingloads,flexiblehousingsandspecialbearings.Referencestotheseadvancesaremade,togetherwithillustrationsofhowtheyaffectpredictedbearingperformance.Experimentalevidenceisalsobeingobtained,whichhelpstoverifyandgiveconfidenceintheanalyticalpredictionsKeywordsjournalbearings,bearingsdesign,hydrodynamiclubrication,bearingstress,bearinghousings,oilgroovesEnginebearingperformanceisdependentuponmanyfactors,fromthemechanicalconfigurationoftheenginetothehydrodynamicsoftheoilfilm.Thispaperhighlightsthemoreimportantfactorstobeconsidered,andrelatesthemtorecentadvances,bothpublishedandunpublished,throughouttheworld.Thereviewattemptsnotjusttoreferencetheseadvances,buttoillustratehowtheyextendtheareasofperformanceprediction,experimentalverificationandthedesignofspecialbearings.Historically,theearliestattemptsatthedesignofdynamicallyloadedbearingswerebasedonmaximumallowablespecificloaddefinedasmaximumappliedloaddividedbyprojectedbearingarea,andthisisstillavaluableparameter.Withtheadventofgraphicalandnumericaltechniquescapableofsolvingahydrodynamicbearingmodel,albeitstillhighlysimplified,estimatesofminimumoilfilmthicknesscouldbemade,andusedasacomparatortojudgethelikelihoodofproblemsonnewengines.Acomprehensivestudyofthoseearlypredictivemethodscanbefoundinthe1967reviewpaperbyCampbelletalIasastudycasethisusedthebigendbearingofaRustonandHornsbyVEBMkIII600hp,600r/mindieselengine.NearlytwentypredictedandexperimentaljournalorbitsfromvarioussourceswerediscussedinthevolumeofI.Mech.E.proceedingswhichcontainedthatpaper,andthesamestudycaseisstillbeingusedbyworkersinthisfieldtodaypolarloaddiagram,Fig1acompletedata,Ref1.Ithasbeenusedinthisreviewtoillustratesomeofthesubsequentadvancesinpredictioncapabilities.Manyofthemajorassumptionsusedintheearlypredictionmethodswerecertainlynotrealistic,butwereusedasexpedientstoobtainamathematicalmodelwhichcouldbesolvedwiththelimitedcomputingcapabilitiesthenavailable.TheseassumptionsincludedcircularrigidbearingsandaperfectsupplyofisoviscousNewtonianoil.Inmanycasesthebearingsurfacewasassumedtobeuninterruptedbyoilfeedfeaturesinthedevelopedfilmpressureregionsand,externaltothebearing,thecalculationofthemainbearingloadstooknoaccountofthecrankshaftandcrankcasestiffnesses.OverthelastdecadeincreasesincomputingpowerhavemeantthatmanyofthoseearlyassumptionsarenolongerDepartmentofApplicationsEngineering,TheGlacierMetalCompanyLimited,Alperton.Wembley,MiddlesexHAO1HD,UKnecessaryandworkhasbeencarriedoutonbearingshapes23elasticconnectingrodbearing4,oilfeedfeaturess6,oilfilmhistory7,andmorerealisticmainbearingloadsharing89.Thisisinkeeping,althoughalittlelate,withthe1967prophecyfromCampbell,whichstatedthatItistheauthorsbeliefthat,withthecontinuingrapidadvanceincomputationalmethodsandwiththegrowingawarenessofthepowerfuldesigntechniqueswhichareAABaDBk¢,,jbEC\\,4\ii\aTCvFig1PolarloaddiagramsforVEBconnectingrodbearingrelativetoaconnectingrodaxis,bcylinderaxis,ccrankpinaxisTRIBOLOGYinternational0301679X/83/0301471803.00©1983ButterworthCoPublishersLtd147MairEnginebearingdesignIi,//Iieaimingforfewerassumptionsdatapresentationforbetterunderstem.dingofresultsbetterpredictionofoperatingconditionsloadsharing,heatbalanceexperimentalverification.Progressineachofthesecategoriesisveryimportamandeachsectioncomplementstheothers.Withtheneedtoconserveenergyandwithfueleconomyamajorissue,manyenginesarenowbeingdesignedwithhigherpowertoweightratiosTheresultanteffectsonbearingsarereductioninbearingsize,higherspecificloadsandtheuseoflowerviscosityoils.AllthesechangesbringtheSimplifiedandquickmethodManydataoresentationtechniquesshowninthispaperelatingtotheVEBbigendstud},caseuseEooKersshortoearingMobilitysolution.TheMobiitycoTcoorqasbeensuccessfullyappliedoverthelastt5years,ano..zexplainedindetailelsewhereu°.itsgreatattractionisthewayLsplitsjournalmovementintotwocononentssqueezeandwhirl,whichenabeaFulIorbitobecaiculatedver/rapidlywithnoreiterativecaicuiationsaeachtimestep.ForcompletenesstheshortbearingVEBerhalcentreorbitisincludedinthenewurvevaforbitsinFig2asupplementingthoseinRefI,andthevariationfnminimumfilmthicknessatdifferenttimestLroughot.theloadcycledefinedbycrankangleisshowniFig3.148983Voi8N3AsecondpartofBookersworkwastoproduceaclearancecirclefilmpressuremap2givingtheratioofthemaximumhydrodynamicpressuretothespecificloadatanypointintheclearancecircle.TheinsetdiagraminFig4showstheclearancecirclefilmpressuremapwiththeVEBorbitsuperimposed.Notethatthisorbitisnotplottedrelativetospacetheconventionalmethodbutonaclearancemapwhichiseffectivelybeingmovedinanangularsensethroughoutthecycle,suchthatthedirectionoftheappliedloadisalwaysdownwards.ThisisanimportantandvaluabletechniquewhenusingtheMobilitymethod.ThemaximumoilfilmpressureisobtainedfromtheserelationshipsandNomenclatureCrradialclearance,mDbearingdiameter,mhminminimumfilmthickness,meeccentricityvectorFforcevectorJlOOfo21ecosO1dO0Lbearinglength,mMMobility,dimensionlessPfoilfeedpressure,NmPmaxmaximumfilmpressure,Nm2PnspecificloadW/LD,Nm2QFoilflowconsideringfilmhistory,m3srigoroussolutionQHhydrodynamicflow,m3s1rapidsolutionQpfeedpressureflow,m3s1rapidsolutionQRflownotconsideringfilmhistory,m3srigoroussolutionQxflowfromexperiments,m3s1Rshaftradius,mrldynamicviscosity,Nsm2eeccentricityratio,dimensionlesskfrictionfactor0angleofoilholefromcentrelineCFseeFig23coandcoarefunctionsofjournalandbearingangularvelocity0.50.40,3G.5E0.20.1F1.875,5o°,.,....,2/0,10.001\,,\\\mL__o90oso5,oCrankangle,degreesFig3ShortbearingfilmthicknessratioVEBdo720MartinEnginebearingdesignitsvariationthroughouttheloadcycleisshowninthemainpartofFig4.AtGECintheUKRitchiendevelopedanewsemianalyticalmethodforpredictingthejournalcentreorbititusesaneasilyobtainedoptimizedshortbearingsolutionwhichhasimprovedaccuracyathigheccentricitiesoverthestandardshortbearingmethodtheorbitoftheVEBbigendbearingisshowninFig2b.Thislooksverysimilartoageneralfinitebearingorbitandapparentlyonlytook16secondstorunonanIBM370/145computerseveralyearsago.Theminimumoilfilmthicknessof0.0033mm0.00013inchesiscomparedinTable1withvaluesfromothersourcesincludingtheresultsofaGECfinitebearingprogramusingthestoreddataapproachseenextsection.Itisseentobewithinthescatterbandofthemorerigorousfinitebearingmethods,butstillmaintainstheadvantageofarapidsolution.Theminimumoilfilmthicknessduringacompletecycleofoperationisoneofthemostsignificantparametersonwhichtojudgebearingperformance.Itisgenerallyusedasacomparatorandrepresentsamajorfactorinrelatingpredictedperformancewithexistingbearingexperienceonsimilartypeengines.Itisdifficulttogiveprecisevaluesofminimumfilmthicknessatwhichbearingdamagemightoccur,asotherfactorssuchashighbearingtemperature,misalignment,inadequateoilfeedarrangementsandadverseenvironmentalconditionswillallhaveaneffect.Bookerllgivessomeguidanceondangerlevelsforfilmthicknessinconnectingrodbearingsforusewithshortbearingpredictionmethods.FinitebearingtheoriesUsingafiniteelementmethodferntosolvethefinitebearingtheory,GeneralMotorsResearchLaboratories2havetheabilitytoconsiderdifferentshapesofbearingandalsotoallowforthepresenceofgrooving.ForaplaincircularbearingGMhavesuccessfullycurvefittedbasicdatafromtheirfembearingmodel,andusedthistodeveloparapidmethod,typicallyreducingcomputationaltimefromhourstoseconds.BothmethodshavebeenappliedtotheProlix1.6672Pn2.540,,350/l/i/25\\m2o_E15.E.E1I0e5iiI1IIi090180270560450540650720Crankangle,degreesFig4ShortbearingmaximumfilmpressureVEBTRIBOLOGYinternational149MartL,.EnginebearingdesignRustonVEBbigend,andFigs2canddshowthejournalcentreorbitforthefiniteelementprogramandcurvefitprogramrespectively.Thesetwoorbitslookverysimilar,Nthoughtherewasaremarkablesavingincomputationaltimeforthecurvefitprogram.Filmthicknessratioandmaximumfilmpressurefromthetwome,hodsarecomparedinFigs5aandb.AlsonotethatthefilmpressurefromtheshortbearingtheoryFig4isverysimilartothatfromthefinitebearingferntheoryFig5boManyestablistmentsnowhavefiniteelementorfinitedifference2Dsolutionscapableofallowingfortheeffectofoilfeedfeaturesonhydrodynamicpressuregeneration,ThetandardVEBstudycase,withitscircumferentialgroove,isnotsuitableforillustratingsucheffects,soinsteadtheintermainbearingofa1.8\itregasolineenginewillbeused.TheleaddiagramisshowninFig6andfurtherdatcanbefoundinReferences6and7oTheorbitsinthetorcdiagramofFig7showthefilmthicknessreducedlocailyasaresultofthepresenceofanoilhole.ttshouldbenotedhowever,thatthesmallestfilmthicknessduringthecyclemaynotnecessarilybeimpairedAdesignmethodhasbeendevelopedattheGlacierMetalCowhi.chaltows,inamorecompleteway,fortheeffectsoffeedfeaturesinthebearingoItconsiderstheseeffectstoflintotwocategories.Thefirstrelatestothedehnentaieffectofthedevelopedpressureregionpassingovertheoilfeedregionhole,grooveetcofthebearing°Thesecondinvolvesthestudyofoittransportwithinthebearo.47Curvfitprogram0.5Finiteelementorcgrarr.........\\o.i,\\\,4090t802705604504,6.30720g_50moE20.CurvefitprogramFmffeelementprogram....../m//I/t/t/W\,j1rC9080£70360450540630720bCroOngledegreesFig5GeneralMotorsrapidcurvefitprogramcomparedrorigorousfernprogramVEB}adimensioMessfilmthickness,b}maximumfilmpressureingoiifilm,andtakesintoaccoumthedeleteriouseffectwhentheoi1fimextentisdepletedduetoinsufficientelibeingavailabletofilItheioadcarryingareaofthebearind.ThissecondcategoryissometimesreferredtoascilfiNstory.elif\ImhistoryMuchofthefundamentalworkonelifilmhistoryandor.film.boundariesmdynamicallyloadedbearingswaspione.rcattheUZKNationalEngineeringLaboratorybytheiateA..AoMilnes16,whoseuntimelydeathleftavodintheknowledgeoftNsveryspecializedfbldoMilneapFroachconsideredaneverchangingan_dme,andmeshatemomach.hefilmboundaries.ArxthermethoddevelopedatGlacierbyJonesconsidered,.......,,.i,eritocaiflOWSusingJfixedfinitedifferencemesh,withcontrolspacebounda.,aroundeachnode.TNslatterapproachwaseasiertoadepandhasbeenusedintheanaGsisofLheintermainbearinwithaholefeedinthe1.8itreengine6,¢sshownvtherighthanddiagramofFig7,thegeneralorbitshapew,thfilmhiscryisqutedifferent{reinpredictionswhenfT.mistoryeffectsareignoredAlthoughthesmallestfimthicknessduringtheioadcycleisagainhardiyaffectedwhenconsideringoifilm.history,onecouldperceiveacasefbrinstancewithalowoilfeedpressurewherethexraradaiexcursionofthejournacentremayro,mcedangereuslsinaifilmthicknesses°TNsemphasizestk,Orectonoshftrotcfion\fg6goZarloaddiagram.rtezainbearingoSS/ftLengine50June1983Vo5o3

注意事项

本文(外文翻译--发动机轴承设计的发展 英文版.pdf)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