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

外文资料--Dynamic Analysis of Fo ur -Bar Be ating -upMechanismwith Joint Cle arance.pdf外文资料--Dynamic Analysis of Fo ur -Bar Be ating -upMechanismwith Joint Cle arance.pdf -- 1 元

宽屏显示 收藏 分享

资源预览需要最新版本的Flash Player支持。
您尚未安装或版本过低,建议您

DynamicAnalysisofFourBarBeatingupMechanismwithJointClearance¹XUEWenliangÏÓ1,CHENGuozhençS2,CHENGeçê3,ZHUZhangchenc71,CHENGLongdiñHš11KeyLaboratoryofTextileScienceTechnology,MinistryofEducation,DonghuaUniversity,Shanghai201620,China2ShanghaiShenAnTextileCo.,Ltd.,Shanghai200020,China3CollegeofMechanicalEngineering,DonghuaUniversity,Shanghai201620,ChinaAbstractForthefourbarbeatingupmechanismofairjetloom,theplainbearingoflinkageisthebearingwithdynamicload,andisimmersedinthelubricantbox.Ifthejointclearanceisconsidered,theresearchonlinkagemovementcouldbeverycomplicated.Inthispaper,thekinematiccharacteristicsoffourbarbeatingupmechanismwithjointclearancewerestudiedbyanalyzingthetraceofjournalcenterandthebalanceofradial,tangentialforces,andbearingload.Theregionofprincipalvibrationanditsformingcauseswerediscussed.Andtheresultscouldinterpretthemeasuringcurvesoffourbarbeatingupmechanismcompletely.KeywordsdynamicanalysisfourbarlinkagebeatingupmechanismjointclearanceCLCnumberTS193.3DocumentcodeAArticleID16725220201004055907IntroductionForthefourbarbeatingupmechanism,thecrankshaftbearingandrockshaftbearingaretheballbearing,andthecouplejournalbearingandcrankjournalbearingarethejournalbearing.Thecrank,coupler,rocker,andtwojournalbearingsareallimmergedinthelubricant,andthereistheradialclearancebetweentheringandpinofjournalbearing.Theclearanceishelpfultotherelativemotionoflinksbyprovidingthespaceofmovingandlubricating,butitalsoleadstothediscontinuousmotionofkinematicpair,whichisthemainreasontoaffectthemechanismdynamiccharacteristics13.Forthemechanismstransferringtheforceandmomentappliedintheindustrymanufacturing,asthejointclearanceenlargingthedynamiccharacteristicswillbedestructiveundertheconditionofhighspeedandhighload.Thejointclearanceoffourbarbeatingupmechanismiswithintherangeoftolerance.Ifrunningsmoothlysomeclearanceinthejointofmechanismisalwaysnecessary.Buttheclearanceisoftenincreasedbywearing,thentheimpactforcescouldcausethevibration,noise,bearingdeterioration,andthewearcouldalsobeincreased.Therefore,thevibrationsbecomeonebasicstudycontentaboutmechanismkinetics.Xietal.studiedtherelationbetweenthedynamicbalanceandthevibration4,andSoongetal.studiedthedynamiccharacteristicsofcranksliderwithjointclearance5.Thedynamicalternatingloadisenduredbythejournalbearingoffourbarbeatingupmechanism.Theforcesoflinksaretransferredbytheoilfilm,andthepincenterofcouplejournalmovesonthetrace.Whentheeccentricityislittle,themotionofrockerisunstable,whichshouldleadtotheinstantaneousimpactbetweentheringandthepinandmoreseriouswear,sothestrongvibrationwillhappenmorefrequently.1FourBarLinkagewithJointClearanceIfthejointclearanceofmechanismiszero,thecentersofbearingandjournalareinthesameposition.Butiftheclearanceappears,twocenterswillbeseparated,whichcanresultintheeccentricity,andthereistheextradegreeoffreedomforthemechanism.ThebeatingupmechanismwithjointclearanceisshowninFig.1,whichisthecrankrockerinversion.ThebearingBismadeupofcrankandcoupler,thebearingCismadeupofcouplerandrocker,therockershaftbearingDismadeupofrockerandgroundlink,andthecrankshaftbearingAismadeupofgroundlinkandcrank.Forthebeatingupmechanism,theconnectingarmpinbearingCiseasiesttobeworn,soitisassumedthatthereisonlytheclearancebetweenthecouplerpinandring,andnoclearanceinotherthreebearings.Inthispaper,themeasuringloomistheZA203airjetloomanditsspeedis450r/min.XYreferencecoordinateframeofmechanismshowninFig.1issetaccordingtothepracticalworkingposition.TheoriginisthebearingcenterofcrankshaftA,andthecoordinateofrockershaftbearingDcenterarexD8mmandyD159.8mm.Theotherparametersare559JournalofDonghuaUniversityEng.Ed.Vol.27,No.42010¹Receiveddate20090115CorrespondenceshouldbeaddressedtoXUEWenliang,Emailxwldhu.edu.cnshowninTable1.Fig.1FourbarlinkageusedforbeatingweftupintoclothTable1MainparametersoffourbarmechanismLinkageLength/mmMass/kgMomentofinertial/kgcm2CrankAB3535.80155CouplerBC752.27114RockerCD14510.42528SleyandsleyswordDE64.953728GroundlinkAD160ThesleyandsleyswordDEistheworkinglinkoffourbarmechanism,whichisintegratedwiththerocker.Whenthesleyreciprocates,thereedpushestheweftintothefellofclothfortheinertiaofsleyandsleysworddrivenbytherockerandelbowpositionofmechanism.Forthelinksoffourbarbeatingupmechanism,themassofsleyandsleyswordincludingtherockerismuchheavierthanotherlinks.Themainbodyofrockingshaftisthesteeltubeoflargediameter.Themotionofrockerisstableanditspropertyofantijammingiswell,sothesleyswordischosenasthemeasuringobjectiveofbeatingupmechanismaccelerationcurve.Apiezoelectricaccelerometerisadsorbedonthesleysworddirectlybythemagneticseat,whichisshowninFig.2.Thesleyswordisshortandstrong,whichoutputsignalcouldreflectsensitivelythedynamiccharacteristicsoffourbarlinkage.ThemeasuringaccelerationcurveofsleyswordisshowninFig.3,whichaccordswiththetheoreticalaccelerationcurve,andcharacterizedin.1Thecurveisnotsmooth,whichmeansthatthetheoreticalsmoothcurvehasbeenaddedbytheoscillationswithdifferentfrequenciesandamplitudesseeFig.4.Fig.2SketchofmeasuringpositionFig.3MeasuringcurveFig.4Contrastbetweenmeasuringcurveandtheoreticalsmoothcurve2Theoscillationswithdifferentfrequenciesexpressstrictperiodical,andthedifferenceisonlytheamplitudesseeFig.3.Forthefourbarbeatingupmechanismwithfixedgeometricalandkinematicparameters,inthefirsttwoor560JournalofDonghuaUniversityEng.Ed.Vol.27,No.42010threeyearstheoutputaccelerationsignalofmechanismwillappearagaincorrectlyinthenextperiod,andthevibrationpulsewithfixedfrequencyandamplitudewillalsoappearagaineveryperiodofcrankangle.Sotheoutputaccelerationsignaloffourbarbeatingupmechanismwithjointclearanceisnottherandomsignal,butthemainbodyofsignalisthesignalwiththestrictperiodicity.Theoutputcurveofmechanismismainlymadeupofsignalswiththestrictperiodicity,andalsoincludessomerandomcomponent.3Therandomcomponentofvibrationwillincreaseastheworkingtimeofloom.Thatistosayastheworkingtimeofmechanismincreases,therandomcomponentofoutputcurvewillbegraduallyimproved.ShowninFig.5,Bistheincludedangleofcoupleroritsextendedlineandcrank.WhenB0bor180b,thecrankandthecouplerareinthesameline,andwhentheaccelerationofcrankiszero,themechanismisinthepositionofelbowlink.WhenB90bor270b,thecrankandthecouplerareverticaleachother,andtheaccelerationofcrankislarge.Accordingtothefourspecialpositionsabove,theswingprocessofsleycouldbedividedintofourregions.Fig.5Bangleoffourbarmechanism2RelativeTraceofCouplerPinCenterwithJointClearanceatStaticBalancePositionAccordingtothemeasuringcurve,thereistheimpactoflinksinthejointclearance.Bymeasuringtheclearanceofcrankbearingis2Lm,andtheclearanceofcouplerpinjournalis42Lm.Soitcouldbeconcludedthattheimpactinthejointclearancewillhappenmainlyinthecouplerpinjournal.2.1CouplerpinjournalwithclearanceTherearetwocylindersofpinholeandjournalshowninFig.6.TheradiusofjournalbearingholeisR,theradiusofjournalisr,andtheradiusclearanceiscRr.ThedistancebetweentwocentrallinesofcylindersistheeccentricityeC1C2.Thecouplerandtherockerconnectedbythecouplerjournalbearingarebothmovableparts,sothebearingandthejournalarealsobothturning.Thereistheoilbetweentwocylinders,andthethicknesshofextrusionfilmishcesinHc1EsinH,1whereEe/cistheeccentricityHistheangleincludedbetweenhandC1C2intheverticaldirection.Fig.6GeometricdimensionofjournalforradialloadFisthetotalloadofjournalbearing,Ubcisthelinearvelocityofpinalongthepinsurface,andUcdisthelinearvelocityofjournalalongtheringsurfaceseeTable2.Table2MainparametersofcouplerpinbearingNominaldimensionofjournalbearingholeandjournal2R/mmWidthofplainjournalbearingL/mmViscositycoefficientoflubricantG/Nsm1RadiusclearancecRr/mm40420.01750.0212.2JournalcentertraceofstaticbalancepositionThecrankandthecouplerarebothimmersedinthelubricantbox.Thelubricantinthejointclearanceofjournalandbearingwillturnwiththem.Thereisthehigherhydrodynamicpressureintheregionoflessclearance,andthelowerhydrodynamicpressureintheregionoflargerclearance,whichleadstothedeliveryhead.Thebearingloadisenduredbythehydrodynamicpressureoflubricantfortheeffectofoilwedge.Thestaticbalancepositionofjournalcenteristhebalancepositionofoilfilmforceandbearingforce.Thereisthedifferencebetweencouplerpinjournalandordinaryradialbearing.1Thedirectionandintensityofloadonthecouplerpinjournalalternateasthetime.2Theswingvelocityofjournalandbearingchangesasthetime.TherelationbetweenbearingloadFanddimensionlessoilfilmforce–isshowninEq.26.5Fc/R2GUbcUcdL,2561JournalofDonghuaUniversityEng.Ed.Vol.27,No.42010whereFisthebearingload,Gisthedynamicviscosity,andUbcandUcdareshowninFig.6.AccordingtothedatainTable3,thebalanceposition7NF,C1C2couldbesolvedbytheinterpolation.Table3BearingparametersofcircularcylinderratioofwidthandradiusL/2R1.0EccentricityE0.100.200.300.400.500.600.70Eccentricangle7/b75.1163.5955.5550.0845.3240.5436.02Oilfilmforce–X0.1970.4150.6801.0291.5242.2963.654Thejournalcentertracecouldbedrawnaccordingtotheeccentricangleandtheeccentricity.Thejournalcentertraceofbearingwiththestaticloadusuallyissemicircle.Buttheloadofcouplerpinjournalwillvaryinthesizeanddirectionastheturningofcrank,sothejournalcenterwillmovealongthetraceofstaticbalanceposition.TherelativetraceofjournalcenterstaticbalancerelativetothecouplerpinjournalholeshowninFig.7is8shaped.ThepolarangleshowninFig.7isthedirectionangleofhole,andthepolarradiusistheeccentricity.Accordingtothefigure,therearethreetimesforthejournalcentercomingintothecircleofE0.1.Whenthecrankangleisat72b114b,itisthefirsttimeforthejournalcentercomingintothecircle,andtheleasteccentricityis0.001.Lesseccentricity,Fig.7Relativetraceofjournalcenterstaticbalancerelativetoholethemargentangleisthecrankanglethesystemstabilityisworseandworse.Whenthecrankangleisat178b192b,itisthesecondtimeforthejournalcentercomingintothecircle,andtheleasteccentricityis0.098.Whenthecrankangleisat302b338b,itisthethirdtimeforthejournalcentercomingintothecircle,andtheleasteccentricityis0.001.AndtherearetwotimesforthecentertouchingtheoutercircleofE1,wheretheangularvelocitiesofcouplerandrockerrelativetothebearingloadFarethesame,buttheirdirectionsarereverse,andtheimpactwillhappenbetweentwolinks.2.3BalancebetweenoilfilmforceandbearingloadFnisthereactionforcecomponentinthedirectionoflinkBClength,andFtisthereactionforcecomponentintheverticaldirectionoflinkBC.Between80band150b,Ftisclosetozero,andat92bFnistheleast.Thebearingreactionforceisenduredmainlybytheoilfilmthicknessh,andifaverticalloadwasplacedonthejournal,theoilwouldsqueezeandthereisthesufficientpressuretosupporttheload.ThepressurecouldbedividedintotheradialforceF0ninthedirectionoftielineandthetangentialforceF0tintheverticaldirectionoftieline.F0nGUbcUcdL5c2E21E22,MC1C2F0t14GUbcUcdL5c2PE1E25/2,LC1C23whereUbcistherelativelinearvelocityofholesurface,Ucdistherelativelinearvelocityofjournalsurface.Thereactionforceofjournalfortheoilfilmwillchangeastheturningofcrank.Thebearingloadistheconcentratedforce,andthereactionforceisthedistributionforce.ThefunctionofradialforceF0nistosupportthejournal.Inthedirectionofturning,thejournalcenterwillmovefortheactionoftangentialforceF0t,andtheeccentricitywillincrease.Thetangentialforcewilldestroythebalanceofjournal.Whenthemainbearingloadisinthedirectionofcouplerlength,thecomponentofforceFtintheverticaldirectionisverylittle.ThepressurecurvesofF0ninthedirectionofcoupleandF0tintheverticaldirectionareshowninFig.8.BecausetheoilfilmforceF0tisnotlikethebearingforceFtwhichisaroundzero,inthisconditionF0tiseasytodestroythestabilityofjournalmotion.562JournalofDonghuaUniversityEng.Ed.Vol.27,No.42010
编号:201311070933463291    大小:699.86KB    格式:PDF    上传时间:2013-11-07
  【编辑】
1
关 键 词:
外文资料 外文翻译
温馨提示:
1: 本站所有资源如无特殊说明,都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
2: 本站的文档不包含任何第三方提供的附件图纸等,如果需要附件,请联系上传者。文件的所有权益归上传用户所有。
3.本站RAR压缩包中若带图纸,网页内容里面会有图纸预览,若没有图纸预览就没有图纸。
4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
5. 人人文库网仅提供交流平台,并不能对任何下载内容负责。
6. 下载文件中如有侵权或不适当内容,请与我们联系,我们立即纠正。
7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。
  人人文库网所有资源均是用户自行上传分享,仅供网友学习交流,未经上传用户书面授权,请勿作他用。
0条评论

还可以输入200字符

暂无评论,赶快抢占沙发吧。

当前资源信息

5.0
 
(3人评价)
浏览:52次
英文资料库上传于2013-11-07

官方联系方式

客服手机:13961746681   
2:不支持迅雷下载,请使用浏览器下载   
3:不支持QQ浏览器下载,请用其他浏览器   
4:下载后的文档和图纸-无水印   
5:文档经过压缩,下载后原文更清晰   

相关资源

相关资源

相关搜索

外文资料   外文翻译  
关于我们 - 网站声明 - 网站地图 - 友情链接 - 网站客服客服 - 联系我们
copyright@ 2015-2017 人人文库网网站版权所有
苏ICP备12009002号-5