Rolling Bearing Damage - Ε. ΣΚΑΖΙΚΗΣ

1 Rolling Bearing Damage Recognition of Damage and Bearing inspectionRolling Bearing DamageRecognition of Damage and bearinginspectionPubl. No. WL 82 102/3 EAStatus 2001 PrefaceRolling bearings are machine elements found in a wide fieldof applications. They are reliable even under the toughest con-ditions and premature failure is very first sign of Rolling Bearing Damage is primarily un-usual operating behaviour of the bearings. The examination ofdamaged bearings reveals a wide and varied range of phenome-na. Inspection of the bearings alone is normally not enough topinpoint the cause of Damage , but rather the inspection of themating parts, lubrication, and sealing as well as the operatingand environmental conditions.

2 A set procedure for examina-tion facilitates the determination of the cause of brochure is essentially a workshop manual. It providesa survey of typical Bearing Damage , its cause and remedialmeasures. Along with the examples of Damage patterns thepossibility of recognising the Bearing Damage at an early stageare also presented at the which are not classified as damaged are also in-spected within the scope of preventive maintenance which is frequently carried out. This brochure therefore contains examples of bearings with the running features common to thelife in page: What may at first appear to be a photo of sanddunes taken at a high altitude is in fact the wave-shaped defor-mation-wear-profile of a cylindrical roller thrust Bearing .

3 There is less than just 1 micron from peak to valley. At a slowspeed mixed friction occurs in the areas stressed by slidingcontact. Rippling results from the stick-slip operating behaviourindicating Damage .. Damage recognition .. monitoring with technical devices .. Damage .. in certain spots .. of Bearing exchange remaining life ..72 Securing damaged bearings .. of operating data .. and evaluation of lubricant samples .. of Bearing environment .. of Bearing in mounted condition .. damaged Bearing .

4 Check .. of complete Bearing .. to FAG or assessment of individual parts of Bearing ..103 Evaluation of running features and Damage to dismounted bearings .. to be taken .. separate parts .. taken with complete Bearing .. Bearing into separate parts .. of Bearing parts .. condition of the seats .. corrosion .. marks or sliding wear .. support of Bearing rings .. grazing tracks .. of Rolling contact .. and significance of tracks .. Normal tracks .. Unusual tracks .. in raceways androlling element surfaces.

5 Fractures .. Corrosion Damage .. False brinelling .. Rolling element indentations .. Craters and fluting due topassage of electric current .. Rolling element edge running .. fractures .. Fatigue fractures as a result of raceway fatigue .. Axial incipient cracks and through cracksof inner rings .. Outer ring fractures in circumferentialdirection .. scratches and smear marks on thecontact surfaces .. Wear Damage with poor lubrication .. Scratches on Rolling element outside diameters.

6 Slippage tracks .. Score marks .. due to overheating .. of lip contact .. to lip and roller faces in roller bearings .. Scoring due to foreign particles .. Seizure in lip contact .. Wear in the lip contact area .. Lip fractures .. of cage guiding surfaces .. to seal running areas .. Worn sealing lip tracks .. Discolouration of sealing track .. Damage .. due to starved lubrication and contamination .. due to excess speed .. due to roller skewing .. in ball Bearing cages due to tilting.

7 Of cage connections .. fracture .. due to incorrect mounting .. Damage .. of sealing lips .. due to incorrect mounting ..594 Other means of inspection at FAG .. measuring of bearings and Bearing parts .. analyses and lubricant inspections .. inspection .. micro structure analysis .. electron microscope investigations .. tests .. of load conditions ..713 FAGPagePageSymptomsSources of troubleExamplesUneven runningDamaged ringsMotor vehicles:or Rolling elementsmore and more wheel wobblingincreased tilting clearancevibration of steering systemContaminationFans:growing Excessive Bearing clearancevibrationSaw mills:more knocks and blowsin connecting rodsReducedWear due Lathe:working accuracyto contaminantsgradual developmentor insufficient lubricationof chatter marks on workpieceDamaged ringsGrinders.

8 Or Rolling elementswavy ground surfaceChange in adjustmentCold Rolling mill:(clearance or preload)Periodic surface defects on rolled materialsuch as stretcher strains,ghost lines operating clearancerunning noise: whining or squealingnoiseElectric motorsrumblingExcessive clearanceGearsor irregularDamaged contact areas(the Bearing noisenoiseContaminationis hard to identifyUnsuitable lubricantsince it is generallydrowned by the noiseof the gears)gradual changeChange in operating clearancein running noisedue to temperatureDamaged running track( due to contamination or fatigue)

9 Unusual operating behaviour indicating damageSubjective Damage recognition Bearing monitoring with technical devicesGradual deterioration of the opera-ting behaviour is normally the first signof Bearing Damage . Spontaneous damageis rare, for example that caused by mount -ing errors or a lack of lubrication, which leads to immediate machine down-time. Depending on the operating con-ditions, a few minutes, or under somecircumstances even a few months, maypass from the time Damage begins to themoment the Bearing actually fails.

10 Thecase of application in question and theeffects of Bearing Damage on the ma -chine operation are taken as a basis whenselecting the type of Bearing monitoringto be provided. Subjective Damage recognitionIn the vast majority of Bearing appli-cations it is sufficient when machineoperators watch out for uneven runningor unusual noise in the Bearing system,see table Bearing monitoring with technical devicesBearings which could be hazardouswhen damaged or which could lead tolong production down-times require onthe other hand accurate and constantmonitoring.