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首页 轴瓦乌金碎裂与碾压(Bearing and crushing of bearing)

轴瓦乌金碎裂与碾压(Bearing and crushing of bearing).doc

轴瓦乌金碎裂与碾压(Bearing and crushing …

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2018-05-02 0人阅读 举报 0 0 0 暂无简介

简介:本文档为《轴瓦乌金碎裂与碾压(Bearing and crushing of bearing)doc》,可适用于社会民生领域

轴瓦乌金碎裂与碾压(Bearingandcrushingofbearing)轴瓦乌金碎裂与碾压(Bearingandcrushingofbearing)BearingandcrushingofbearingBearingshellsharplyfractureiscommoninsmallandmediumsizedunits,sharplyrollingonthelargeunitisrelativelycommon,onceappear,andthesefailuresbeforedidnotfindoutthecauseoftheproblemandfindoutsomeeffectivemeasures,willhappenfrequently,whichhavetofrequentdowntimecheckandreplacethebearingshellTherefore,thesefaultsarenotmalignant,buthavegreatinfluenceontheutilizationrateandsafetyoftheunitthegeneralsituationandcharacteristicsoftheaxialandcrushingaccidentsThecrushingandcrushingofaxialujinisgenerallyfoundinthenewmachine,andsomeoftheunitshavebeenrepairedTheRCCcanbeformedatatimewhentheunitisstoppedThefracturingoftheujinisusuallyformedbytheoperationofweeks,andthefewunitswithspecialfaultscanbeformedinoneortwodaysTheimageshowsaMWbackpressureturbinewithwattsoflowertiles,andthenewtileisbrokenaftermonthsofoperationItcanbeseenfromthefigurethattheaxialfragmentationisevenlydistributedalongtheaxiallength,andtheujinfractureoccursinthehighestoilfilmpressureregionintheworkingstate,andthedamagededgeisevenlydistributedalongtheboundarylineoftheoilcapsuleFromthefragments,someofthepieceshadfallenoffcompletelyfromthetile,andalargegaphadbeenformedbetweenthemThisphenomenonshowsthatafterthefracturingoftheujin,afteralongtimerunning,themarginalsmallcracksdevelopandformthegranulesandarewashedawaybytheoilflowIngeneral,thebearingofthegroupisnotinstalledinthetemperaturemeasuringpoint,sothefracturingoftheujinisdifficulttofindintheoperationoftheunitHowever,evenifthetemperaturemeasurementpointsareinstalledontheujin,ifthemeasuringpointisnotinthezoneofujin,thentheujintemperatureisnotabnormalafterthefracturingAndeventhoughthetemperaturemeasurementpointsareintheujinfragmentationarea,theujintemperatureisnoabnormalafterthefracturingOnlywhentheshaftneckandthetemperaturemeasurementpointaredirectlytouchingtheextremelyshortmomentAsthetemperaturerises,thetemperaturemeasurementpointsarequicklydamagedduetogrindingTemperaturemeasurementpointdamageisacommonfaultoftherunningunit,anditisnotusuallycausedbythedisintegrationoftheuljinSosomeunitsbearingcataclasticcontinuestorun,afterthedebrisareaisdecreasing,thejournalwithtiledirectlytouchingground,thusnotonlymakethejournalseriouswearandtear,andastherotor,severewearonflowpassageThebearingpressureofthebearingisthattheujinissubjectedtoexcessivecompressivestress(dynamic,staticload),orthetemperatureoftheujinisraisedandsoftened,resultinginextrusiondeformationundernormalpressureTheextrudedujinfirstblockstheoilholeinthetopoftheroof,thensqueezestheujinintothinslices,whicharebroughttoandaccumulatedinthemidsectionoilgapbytherotatingshaftneckWhenthetemperatureoftheujinistoohigh,andthesofteningproducesplasticdeformationorwear,thehightemperatureoftheujinisattachedtotheshaftneck,whichcausesagnawingoftheujin,whichcausesmoreseriousdamagetothebearingIfsharplyplasticdeformationandweardamagethenormaloilwedge,loweroiltoreduceorblockcanmakesharplytemperaturerisesharply,sothiskindoffaulthandlingabitnotintime,cancausebearingshellburnedThefallingoftheujinrotorscausessevereminegrindingandaseriesoffailuresandaccidents,butthisfailurecanbeeffectivelypreventedbymonitoringtheujintemperaturemechanismandcauseofthebearingfractureofthebearingInordertocorrectlyunderstandthecausesofujinandtoformulateeffectivecountermeasures,itisnecessarytofindoutthemechanismofthefracturingoftheujinthemechanismandprocessofujinfragmentationIntheworkingspeedoftherotor,theoilfilmwithathicknessofmumbetweentheshaftneckandtheujinisdeterminedbythediameteroftheshaft,theshapeoftheshaft,therotationalspeed,etc,andthereisarelativevibrationbetweentheshaftneckandtheshaftFurther,theexcitationforceontherotorpassesthroughtheshaftneckandtheoilfilmtothebearingseat,causingtheoilfilmtoproducealternatingforceWhenthestressistoohigh,thesurfaceoftheujinwillformasmallfatiguecrack,andthenthepressureoftheoilfilmpressurewillcrackintothesmallcrack,sothatthesmallcrackswillexpandandpenetrate,andtheujinwillformthebrokenpiecesThesefragments,undertheinfluenceofalternatingoilwedgeforces,fallofffromthetile,causingthebrokenpiecestocollideandchangethepressureoilwedgeintothesmallcrackThedebrisiscontinuetobreakintopieces,smallpiecesareconstantlyflowwashedaway,decliningsharplybearingarea,andfinallysothepressureistoohigh,softentemperaturerisesharply,theremainingbearingsharplyextrusionintothinslices,squeezedoutfromtheoilgap,rotor,shaftneckandtyresaremilldirectlyThisissharplyduringtheprocessoffracturedamage,butbecauseofthesharplyafterfracture,journaloncataclasticsharplystillcancontinuetorunalongtime,somostoftheunitbeforethefracturedsharplyaftermelting,stopcheckthebearingshellcanbefoundasshowninthesituation,therebypreventingthedamageofjournallaterTherefore,itismorecommoninthefield,buttheaccidentsoftheshaftneckandtheflattirearesmallerreasonsforthefracturingoftheujinTheresultsshowthattherearetworeasonsforthefracturingofthebearing:oneisthattherelativedisplacementoftheshaftneckistoolarge,whichcausesthepressureofthelargeralternatingoilfilmThesecondisthestiffnessandresistanceofoilfilm,whichcannoteffectivelycushionanddamptheoilfilmThereasonsfortherelativedisplacementoftheaxialradialrelativedisplacement,thestiffnessoftheoilfilmandthesmalldampingarediscussedTheaxialradialrelativedisplacementistoolargeThereasonsfortherelativedisplacementofaxialradialrelativedisplacementare:()therotationaxisisexcessivelyvibratingTherelativeamplitudeoftherotationaxisisproportionaltotheexcitationforceandthebearingstiffnessofthebearing,whichisinverselyproportionaltothestiffnessoftheoilfilmTheaxialamplitudeisproportionaltotheexcitationforceandinverselyproportionaltothedynamicstiffnessofthebearingUnitshaftamplitudecommonlyso,Janegroundreflectstherelativevibrationshaftsize,butforsmallandmediumsizedturbinebearing,assmallerqualityofrotor,bearingsupportdynamicstiffnessrelativequality(rotor)islarger,andunderthesmallshellamplitude,axisrelativevibrationislargerInstead,largeunitsteamturbine,especiallythelowpressurerotorandgeneratorrotorbearing,bearingsupportdynamicstiffnessislow,underthesmallshellamplitude,axisrelativevibrationcannottoobig,sothebearingshellsharplyruptureoccursmostlyinsmallandmediumsizedturbinebearing,largegeneratorshaftfracturedsharplyraredefectCausesoftheshaftrelativevibrationexcitingforceistoolarge,therelativevibrationcausedbytherotationofexcitingforceandbearingvibrationexcitingforce,thefailurecauseoftheseexcitingforcewithitsdiagnosismethod,inthesecondchapterhasintroducedindetailinsectionTherearetwomainkindsofexcitationforcethatcausetherelativevibrationoftheaxisofrotation,oneistherotorunbalanceforce,whichincludestherotorthermalvariationandthepermanentbendingThesecondistheaxialhalfspeedvortex()theoriginalswingofthebearingistoolargeTheoriginalpendulumvalueoftheshaftistoolarge,andtherotationoftherotorisliketherelativevibrationoftherotatingshaft,whichcanalsoleadtothelargepressureofthealternatingoilfilmThereasonsfortheexcessivependulumswingare:)axialmachiningerrorTheshaftneckprocessingisbad,makeitsellipsepassesbig,sometimesintheneckaxiallengthofasmallellipsethroughthebig,willcausetheujintobreakupFromalargenumberofmeasureddata,whentheellipticityexceedsmm,itwillresultinthedisintegrationofujinTherefore,theellipticityshouldbelessthanmmfortheaxialneckandtherunningofthenewunitduetowearCheckshaftneckovality,willontilepeel,axiallengthuniformlydistributedalongtheaxisneckmeasuringplane,andthecircumferenceofeachmeasurementplanecanbedividedintoeightparts,measuredwithadialindicatoralongtheverticaldirectioninturneachpointofthecircularflatmachineshakependulumvalue,andthencalculateeachplaneinthedirectionofmaximumdiameterdifference,thedifferenceiscalledtheovalityEachplaneellipseshouldbelessthanmm)rotorbendingTheunbalancecausedbypermanentbendingorthermalbendingoftherotorcanbecompensatedbyaggravation,butitwillincreasethependulumvalueoftheshaftTherearesomerotorsthatarebent,andbyaggravating,theaxisvibrationissatisfied,butthenthebearingisbrokenThepermanentbendingoftherotorcausestherotationoftheaxlestobechecked,whichisthesameastheconcentricitymethodinthefourthsectionofthesecondchapterTheheatbendingoftherotorcausestheaxialwobbletoincrease,andtherelativevibrationoftherotorisincreasedornot)axialconnectionconcentricitybiasShaftconnectionconcentricitydeviation,ismainlyduetothecouplingreaminginstallationandoverhaul,thetworotorhasfailedtocausetheconcentric,sowhentheshaftafterthebolttightening,causedbythedifferentheartoftworotorshaftnecksetvalueistoolargeThestiffnessanddampingofaxialoilfilmareinsufficientPantilenormalcircleandellipseofoilfilmhasgoodbufferanddampingaction,butforsomeneedsandtraditionalhabitsofscrapingtile,oftenunderthewillofthetwobearingstilescrapingintoshapeasshowninfigureoilcapsuleAlargenumberoffieldtestsprovedthatthiskindofbearingvibrationresistancelessoilscrapercapsuleshellismuchlower,sosomeunitsafterstartupandcommissioningwasputintooperation,frequentsharplyfracture,butthemeasuredaxisrelativevibrationislessthanmicrons,thejournaleachpointsetvalueislessthanmmThevibrationoftherotatingshaftwasfoundinthenormalloadprocess,andthevibrationincreasedtomum,whichlastedonlyminAlso,someoftheunitsundertherminandcarryingloadprocess,therotorvibrationarelessthanmicrons,onlyintheprocessoftheunitstartstop,throughthecriticalspeed,rotorshaftvibrationofmicrons,onlytotimesofstartstop,jietileinspection,foundthatsharplyhasobviousfracture,thefracturezoneasshowninfigure,alongtheoilsacborderFortheseunits,itismoredifficulttoreducetherelativevibrationoftheshaftAsimpleandeffectivemeasureistoimprovethebearingvibrationresistance,increasetheoilfilmthicknessanddamping,thespecificmeasuresarebearingshellafterthecar,thefluctuationoftileedgingslightlyrevised,slipsdonotmakeanyrepairsThroughtheexperimentofmultiplemachines,anewtilecouldonlybeusedforhalfamonthtobreakupandreplacethebearingofoilfreefolliclesAfteryearsofoperation,therewasnosuchaccidentItisprovedthatthereasonofthefracturingoftheshaftoftheoilbladderiscausedbytherelativevibrationofthesmallaxialneck,whichisduetothesignificantdecreaseintheantivibrationperformanceofthebearingthecausesandmechanismofthebearingofthebearingIfthefracturingoftheujiniscausedbythedynamicload,thesqueezingoftheujiniscausedbythestaticloadandtheexcessivetemperatureoftheujinHowever,furtherresearchhasfoundthattherelativevibrationoftheshorttimeaxialneckcancausethecrushingofujininadditiontothesimplestaticloadoverloadThereasonsandmechanismofthetwokindsofloadingarediscussedindetailbelowstaticloadTheaxialstaticloadmainlycomesfromtherotorThesecondisthepreloadontherotorThepreloadingsourceontherotorhasbeenintroducedinsectionofchapterTheoperationoflargesetsofimported,importedanddomesticsteamturbinelowpressurerotorbearing,duetothedesignpressureisquitehigh,sothedesignthoughchosepantilecarryingcapacityofthehighestcircle,buttheruntimethesesharplyrollingbearingoftenoccurThegenerationofthisrollerissuspectedtobeduetothefailureoftheoilfilmtoestablishtheoilfilminthediskandatlowspeed,andtheshaftoildoesnotlifttherotorItisprovedbythemeasuredaxialbuoyancythatitisnotFIGshowstherelationshipbetweenthevolumeandrotationalspeedofadomesticMWunit(thefronttileoflowpressurerotorII)Byfigure,barring(startjackingoilpump)whentheshaftneckfloatamounttomicrons,bearingshelltemperaturesharplywithimportedoiltemperatureverycloseto,ranaftertheturnspeedofmorethanrmin,shaftneckfloatamountismorethanmicrons,atthistimewasnotsignificantlyelevatedtemperaturesharply,clearlyverysharplytemperatureisaboverminandafterloading,thegeneralisCFromthebearingpressureanalysis,lowpressurerotorbearingpressureareusuallyonthehighside,numericalMpa,andthanthepressureofthebearingsurfaceareaiscalculatedbyjournal(LD)projectionarea,itismuchbiggerthantheshaftneckconfinedarea,sosharplyactualbearisbiggerthanpressureiscalculatedAssumethatjournalandthebearingcontactAngle,bearingandthebearingcontactarclengthisD,consideringbothsidesofthebearingcontactwiththejournaltheexistenceoftheoilfilmpressure,alsocanundertakepartoftheload,toaconservativeestimate,TheactualpressureareaoftheaxialneckisDL,sotherealratioofujinisMpa,whichishigherthanthecalculatedvalueGeneralsharplyatroomtemperatureunderthecompressivestresswillnotproduceplasticdeformation,thatistosay,intheoperationofbusbarsharplyrollingdeformation,temperaturewillrise,strengthdecreaseafterplasticdeformationAfterthelongdriveandlowspeedheatingmachine,themachineischeckedandtheujinisintact,whichindicatesthattheaboveanalysisisrealisticThetemperatureriseofthegeneralassemblyismostlyatahigherspeedThisisduetoincreasedpressure,increasesignificantlyunderthehighspeedbearingfrictioncalorificvalue,whenitscalorificvaluecannotbeoilflowawayentirely,heataccumulation,asspeedincreasessharplytemperaturesignificantlyhigherWhenthetemperatureroseto,thesharply,thoughnotsoften,butitsstrengthwilldecrease,whichwillproduceacertainrollingdeformationIfthedeformationcausesthewedgetobedamaged,theoilcontentofthelowertilewilldecrease,thetemperatureoftheujinwillriserapidly,andtheujinwillproducealargerplasticdeformationWhentheoilwedgeisseverelydamaged,thetemperaturewillincreasesharplyEvenifthebrakestops,thetemperatureofujinwillcontinuetoriseRunalotofexperiencehasshownthatwhensharplyraisedtoCtemperature,hitsthebrake,eventuallysharplytemperaturesoftenexceedC,andC,sharplyinevitablyproduceseverewhenrollingandwearSharplyaboveCtemperature,finally,becauseofthesharplyseriouswearandtear,damageoftemperaturemeasuringpoint,thusthefinaltemperaturesharplytherehaschecked,butfromtheaccidentsharplyafteralargenumberofmeltingolowphenomenonanalysis,sharplytemperaturehasmorethanCintheendSharplytoavoidabearingsrolling,wear,melting,axlebushsharplyintheequipmentoperationtemperatureshouldnotbeonlyamaximumvalue,atthesametimeshouldalsobestipulatedtemperaturereachesacertainlimitofallowabletemperatureriserate,thustoensurethatwhenthetemperaturerisesharplytoacertainlimit,hitsthebrakeprocessisstillwithinthepermittedtemperaturecontinuestoriseFieldandsomeunitsbearingpressureisnothigh,butalsocanformsharplyseverecrushandwearandtear,thisisduetothebearingrepairdamagedthenormalafterscrapingoilwedgeorbearinggapistoosmall,causedbylowersignificantlyreducetheamountoftheoilthatisscrapingtileprocessandimpropermaintenanceAtpresent,thelowpressurerotorofthelargeunitistoohigh,anditisaprominentproblemthatthefrictionandweararefrequentlyproducedIntermsofeliminatingcountermeasures,thefactorieshavemademoreattempts,buttheeffectisnotsatisfactoryThesemeasuresinclude:LowerthanpressureAtpresent,itisusedtoreducethestaticloadofthistileHowever,theadjustmentisnotlargeduetothepressurelimitationoftheadjacentbearingReducetheoiltemperatureofthebearingAccordingtoseveralunittests,thetemperatureoftheujintemperaturedecreaseswiththedecreaseoftheoiltemperatureoftheimportedoil,buttheadjustmentamountisnotlargeLowertheoilscraperExperimentsonseveralunits,loweroilscrapercapsulehassomeeffectstosharplylowertemperature,butnotsignificantly,andcanmakelargermechanicalimpurityparticlesinoilintothenexttile,tilesharplyandshaftneckunderseriousscratchesImprovethescrapingprocess,butthebearingisnottobeshavenAlthoughtherearealotofoperatingexperienceshowsthatsharplytemperaturehasgreatinfluencewithscrapingtileprocess,butifimprovescrapingtileprocess,sharplytoreducetemperature,thentheoriginalhightemperatureiscausedbyimproperscrapingtiletechnology,and,arguably,itisagoodblowabricklayer'stechniquewithbearingbushisbetterthanmachinefinishingcartoensureoilwedge,thustheuseofbearingbushshouldimprovemachiningqualityandtechnology,toimprovethejournalcontactwithsharply,trynottoblowbybuildingtoimprovethejournalcontactwithsharplyButatthemoment,inadditiontothethreeoilwedgeandtiltingatthescenenotblowingoutside,otherbearingshellarebydifferentdegreeofrepair,andmanybearingbushonceuse,thereforescrapingtilethistechnologyindomesticinarelativelylongperiodoftimewillalsocontinuetobeusedInadditiontoensuringthattheaxialaxialandujincontactsareevenlydistributed,itismoreimportanttoensurethatagoodoilwedgeisestablishedintheoperationTherefore,theaxialradialcontactshouldtaketheweightofthelowertilecenterlineandtheprincipleofgradualreductiononbothsidestheaxialvibrationistoolargeJournalofrelativevibrationlimitvalueisequaltothebearingclearancevalue,thisphenomenoniscalledthelimitcycleinvibration,itsphysicalmeaningisdirectcontactwiththeshaftneckandsharplyandwhenthecontactpressureoversharplymaterialpressurecanbesharplyrollingdeformation,deformationoccursfirstonthebadoilfilmformationandaxialends,duetothelargevibrationtimeisnotlong,soshaftneckislessvibrationvalueisformedsharplyruptureismuchlarger,butnotsharplygeneralfracture,andthereisnoimpactbearingshellinput,sowillnotrisesharplytemperature

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