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Add:1658# Jinshajiang Rd., Kunshan, Jiangsu, China 

PC:215300

Fax:+86-0512-57703924

Website： http://www.nichjo.com

E-mail： nichjo@nichjo.com

Business 1 Tel+86-512-57704998

Business 2 Tel:+86-512-57729081

Technical Support Tel:+86-512-57715918

Procurement 1 Tel:+86-512-57729087

 

Copyright：Jiangsu Risheng Bearing Co.,ltd  |  Copyright - 2018 All Rights Reserved.  苏ICP备19018804号   Powered by www.300.cn

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Rolling

Rolling bearing damage

Whentherollingbearingisdisassembledandinspected,thebearingfailureandthecauseofdamagecanbejudgedaccordingtothedamageofthebearing. 1.RacewaysurfaceMetalpeelingbearingrollingelementsandinnerandouterringracewaysaresubjectedtoperiodicpulsatingloads,resultingincyclicallyvaryingcontactstresses.Whenthenumberofstresscyclesreachesacertainvalue,fatiguepeelingoccursontherollingelementortheinnerandouterringraceways.Ifthebearingloadistoolarge,thisfatiguewillbeexacerbated.Inaddition,thebearingisnotinstalledcorrectly,theshaftisbent,andtheracewayispeeledoff.Fatiguespallingofthebearingracesreducestheaccuracyoftheshaftandcausesvibrationandnoiseinthemechanism. 2.Thebearingburnedandburnedhasatemperingcolorontheracewayandrollingelement.Thecausesofburnsaregenerallyinsufficientlubrication,thequalityofthelubricantdoesnotmeettherequirementsordeterioration,andthebearingassemblyistootight. 3.Unevenpitsappearonthecontactsurfacebetweentheracewayandtherolleroftheplasticdeformationbearing,indicatingthatthebearingisplasticallydeformed.Thereasonforthisisthatunderalargestaticloadorimpactload,thelocalstressoftheworkingsurfaceexceedstheyieldlimitofthematerial,whichgenerallyoccursonbearingsrotatingatlowspeed. 4.BearingringcrackThebearingringiscrackedbecausethebearingistootight,theouterringorinnerringofthebearingisloose,thebearingpartofthebearingisdeformed,andthesurfaceofthebearingispoorlyprocessed. 5.Thecageisbrokenduetoinsufficientlubrication,brokenrollingelements,andskewedraces. 6.Thereasonwhythemetalofthecageadherestotherollingelementsisthattherollingelementsarecaughtinthecageorinsufficientlylubricated. 7.Seriouswearoftheracewaymaybeduetoforeignmatterfallingintotherace,insufficientlubricantorimproperlubricantgrade.Themainfactorsaffectingrollingbearingsare:load,lubrication,assembly,environmentalconditionsandmaterialormanufacturingaccuracy.
2019-03-01 11:06
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Technology Center
Bearing

Bearing operation check and fault handling

Theinspectionitemsinoperationincludetherollingsound,vibration,temperature,andlubricationstatusofthebearing.Thedetailsareasfollows: 1.Rollingsoundofthebearing Thesounderisusedtocheckthesizeandsoundqualityoftherollingsoundoftherunningbearing.Evenifthebearingisslightlypeeledoff,abnormalsoundsandirregularsoundsareemitted,whichcanbedistinguishedbythesounder. 2.Bearingvibration Bearingvibrationisverysensitivetobearingdamage.Forexample,peeling,indentation,rust,crack,wear,etc.arereflectedinthebearingvibrationmeasurement.Therefore,vibrationcanbemeasuredbyusingaspecialbearingvibrationmeasuringdevice(frequencyanalyzer,etc.).Thesizeoftheabnormalitycanbeinferredbyfrequencyanalysis.Themeasuredvalues​​varydependingontheconditionsofuseofthebearingorthemountingpositionofthesensor.Therefore,itisnecessarytoanalyzeandcomparethemeasuredvalues​​ofeachmachineinadvancetodeterminethejudgmentstandard. 3.Bearingtemperature Thetemperatureofthebearingisgenerallyestimatedbythetemperatureoutsidethebearing.Iftheoilholecandirectlymeasurethetemperatureofthebearingouterring,itismoresuitable.Usually,thetemperatureofthebearingrisesslowlyastheoperationstarts,andreachesasteadystateafter1-2hours.Thenormaltemperatureofthebearingvarieswiththeheatcapacity,heatdissipation,speedandloadofthemachine.Ifthelubricationandinstallationpartsaresuitable,thebearingtemperaturewillrisesharplyandabnormaltemperaturewilloccur.Atthistime,itisnecessarytostoptheoperationandtakenecessaryprecautions. 4.Lubricate 4.1Theroleofbearinglubrication Lubricationhasanimportantinfluenceonthefatiguelifeofrollingbearingsandfriction,wear,temperaturerise,vibration,etc.Withoutnormallubrication,thebearingscannotwork.Analysisofthecauseofbearingdamageindicatesthatabout40%ofbearingdamageisassociatedwithpoorlubrication.Therefore,goodlubricationofthebearingsisaneffectivemeasuretoreducebearingfrictionandwear.Inaddition,thelubricationofthebearingalsohasvariousfunctionssuchasheatdissipation,rustprevention,sealing,andshockmitigation.Theroleofbearinglubricationcanbebrieflyexplainedasfollows: a.Forminganoilfilmbetweenthetworollingsurfacesorslidingsurfacesthatcontacteachothertoseparatethetwosurfaces,reducingfrictionandwearonthecontactsurface. b.Whenusingoillubrication,especiallywhenusingcirculatingoillubrication,oilmistlubricationandfuelinjectionlubrication,thelubricatingoilcantakeawaymostofthefrictionheatinsidethebearingandeffectivelydissipateheat. c.Whengreaselubricationisused,foreignmattersuchasdustcanbepreventedfromenteringthebearingandsealing. d.Lubricantshavetheeffectofpreventingmetalcorrosion. e.Extendthefatiguelifeofthebearing.   4.2Comparisonofgreaselubricationandoillubrication Thelubricationmethodofthebearingisroughlydividedintotwotypes:greaselubricationandoillubrication.Inordertogivefullplaytothefunctionofthebearing,itisimportanttousealubricationmethoddependingontheconditionsofuseandthepurposeofuse. 4.3Greaselubrication:Greaseisalubricantcomposedofbaseoil,thickenerandadditives.Whenselecting,youshouldchooseagreasethatisverysuitablefortheconditionsofuseofthebearing.Duetothedifferenttrademarks,therewillbegreatdifferencesinperformance,soyoumustpayattentionwhenchoosing.Commonlyusedgreasesforbearingsincludecalcium-basedgreases,sodium-basedgreases,calcium-sodium-basedgreases,lithium-basedgreases,aluminum-basedgreases,andmolybdenumdisulfidegreases.Theamountofgreasefilledinthebearingispreferably1/2-1/3oftheinternalspaceofthebearing.Itshouldbereducedto1/3athighspeed.Excessivegreasecausesthetemperaturetorise.   4.4Selectionofgrease:Whenselectinggreaseaccordingtoworkingtemperature,themainindicatorsshouldbedroppingpoint,oxidationstabilityandlowtemperatureperformance.Thedroppingpointcangenerallybeusedtoevaluatehightemperatureperformance.Theactualworkingtemperatureofthebearingshouldbelowerthanthedroppingpointof10-20°C..Syntheticgreaseshouldbeusedatatemperaturebelowthedroppointof20-30°C.Whenselectingthegreaseaccordingtothebearingload,thegreasewithasmallpenetrationshouldbeselectedfortheheavyload.Whenworkingunderhighpressure,inadditiontothesmallpenetration,italsohashigheroilfilmstrengthandextremepressureperformance.Whenselectinggreaseaccordingtoenvironmentalconditions,calcium-basedgreaseisnoteasilysolubleinwaterandissuitablefordryingandlowmoistureenvironments.   4.5Oillubrication:Underhigh-speedandhigh-temperatureconditions,oillubricationcanbeusedwhengreaselubricationisnotsuitable.Alargeamountofheatcanbetakenawaybythecirculationofthelubricatingoil.Viscosityisanimportantcharacteristicoflubricatingoil.Theviscositydirectlyaffectsthefluidityofthelubricatingoilandthethicknessoftheoilfilmformedbetweenthefrictionsurfaces.Theviscosityofthelubricatingoilattheworkingtemperatureofthebearingisgenerally12-15cst.Thehigherthespeed,thelowertheviscosity,andtheheaviertheload,thehighertheviscosity.Commonlyusedlubricatingoilsincludemechanicaloil,high-speedmechanicaloil,turbineoil,compressoroil,transformeroil,cylinderoil,andthelike.   Oillubricationmethodsinclude:   a.Oilbathlubrication:Oilbathlubricationisthemostcommonlubric
2019-03-01 11:06
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