23291499 bearing failure

8/4/2019 23291499 Bearing Failure

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ANALYSIS OF BEARINGANALYSIS OF BEARING

FAILUREFAILURE(ROLLING CONTACT BEARING)ROLLING CONTACT BEARING)

Prepared By: Mahida VivekPrepared By: Mahida VivekBEBE 44thth, 8, 8thth semester (mech)semester (mech)

Valia Institute Of Technology, ValiaValia Institute Of Technology, Valia

Guide: Sandeep DaveGuide: Sandeep Dave


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Introductionntroduction Bearing are among the most importantBearing are among the most important

component in industries.component in industries.

Unfortunately it sometimes happens that aUnfortunately it sometimes happens that a

bearing does not attain its calculatedbearing does not attain its calculated

rating life.rating life.

There may be many reasons for it.There may be many reasons for it.


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How is bearing life defined?How is bearing

life defined?

Bearing cannot rotate for ever.Bearing cannot rotate for ever.

The life of a bearing is defined as theThe life of a bearing is defined as the

number of revolutions the bearing cannumber of revolutions the bearing can

perform before incipient flaking occurs.perform before incipient flaking occurs.

This does not mean to say that theThis does not mean to say that the

bearing cannot be used after then.bearing cannot be used after then.


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Rolling Bearing PartsRolling Bearing Parts

The parts and nomenclaturefor a Ball Bearing

Outer Race

Inner Race

Ball

Cage or Separator

Bore


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True Brinell i lngrue Brinell i lng Using hammer toUsing hammer to

install.install.

Dropping a bearing.Dropping a bearing. Pressing a bearingPressing a bearing

onto a shaft byonto a shaft by

applying force to theapplying force to the

non-rotating ring.non-rotating ring.


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Contaminationontamination It includes airborneIt includes airborne

dust, dirt or anydust, dirt or any

abrasive substanceabrasive substancethat gets into thethat gets into the

bearing.bearing.

Contamination resultsContamination results

in bearing vibrationin bearing vibrationand wearand wear


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Electrical FlutingElectrical Fluting

It occurs when aIt occurs when a

current is passedcurrent is passed

through the bearing.through the bearing. Frequently seen inFrequently seen in

electric motors can beelectric motors can be

eliminated byeliminated by

ceramic-coating theceramic-coating theOD of the bearingOD of the bearing


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Misalignment FailureMisalignment Failure

Bent shaftBent shaft

Burrs or dirt on theBurrs or dirt on the

shaft or housingshaft or housingshoulders.shoulders.

Shaft threads are notShaft threads are not

square with the shaftsquare with the shaft

seats.seats.


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Reverse loadingeverse loading Occurs when loadsOccurs when loads

shift direction inshift direction inbearing that can onlybearing that can onlytake axial load in onetake axial load in onedirectiondirection

The thrust loadThe thrust loadapplied to the wrongapplied to the wrongbearing face result inbearing face result ina wear band on thea wear band on theballsballs


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Corrosion Failureorrosion Failure It result from theIt result from the

chemical attack onchemical attack onthe bearing materialsthe bearing materialsby hostile fluids orby hostile fluids oratmospheres.atmospheres.

It increased vibrationIt increased vibrationfollowed by wear,followed by wear,with subsequentwith subsequentincrease in radialincrease in radialclearance.clearance.


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Excessive load failurexcessive load fai lure Excessive loadExcessive load

normally causesnormally causes

premature bearingpremature bearingfailure.failure.

It show heavier ballIt show heavier ball

wear paths and morewear paths and more

widespread andwidespread anddeeper spalling.deeper spalling.


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Loose fit fai lureoose fit fai lure Caused by relativeCaused by relative

motion between partsmotion between parts

which, in turn, causeswhich, in turn, causesfrettingfretting

This normally occursThis normally occurs

through outer ringthrough outer ring

slippage in theslippage in thehousing due tohousing due to

improper fitsimproper fits


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Lubrication failureubrication failure Restricted lubricantRestricted lubricant

flow or excessiveflow or excessive

temperatures thattemperatures thatdegrade the lubricantdegrade the lubricant

property cause failureproperty cause failure

It lead to excessiveIt lead to excessive

wear, overheatingwear, overheatingand subsequentand subsequent

bearing failure.bearing failure.


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OverheatingOverheating

It discoloration of theIt discoloration of the

ring, balls/rollers andring, balls/rollers and

cages from gold tocages from gold toblueblue

Temperatures inTemperatures in

excess of 400 degreesexcess of 400 degrees

C.C. Result in deformationResult in deformation

of balls and ring.of balls and ring.


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Preload failurereload fai lure If interference fitsIf interference fits

exceed the internalexceed the internal

radial clearance, theradial clearance, therolling becomerolling become

preloaded.preloaded.

Continued operationContinued operation

can lead to rapid wearcan lead to rapid wearand fatigueand fatigue


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Fatigue fai luresatigue failures Metal fatigue is caused by repeatedMetal fatigue is caused by repeated

cycling of the load.cycling of the load.

Variation in the stress ratios canVariation in the stress ratios cansignificantly affect fatigue life.significantly affect fatigue life.

The most commonly used stress ratio ofThe most commonly used stress ratio of

the minimum stress to the maximumthe minimum stress to the maximumstress.stress.


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Preventing fatigue failurePreventing fatigue failure

To improvement in design.To improvement in design.

Avoid sharp surface tears.Avoid sharp surface tears.

Prevent the development of surfacePrevent the development of surface

discontinuities.discontinuities.

Reduce or eliminate tensile residualReduce or eliminate tensile residual

stresses caused by manufacturing.stresses caused by manufacturing.

Improve the fabrication procedures.Improve the fabrication procedures.


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Installation damageInstallation damage

Occurs when a sharpOccurs when a sharp

impact is appliedimpact is applied

incorrectly to aincorrectly to abearing duringbearing during

mounting ormounting or

dismountingdismounting

To prevent it useTo prevent it useproper method.proper method.


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Reducing bearing fai lureeducing bearing failure Proper bearing selection.Proper bearing selection.

Bearing handling and storage.Bearing handling and storage.

Bearing installation and handling.Bearing installation and handling.

Ongoing bearing lubrication.Ongoing bearing lubrication.

Bearing maintenances and care.Bearing maintenances and care.


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Conclusiononclusion By examining aBy examining a

damaged bearing, it isdamaged bearing, it ispossible, in thepossible, in themajority of cases, tomajority of cases, toform an opinion onform an opinion onthe cause of thethe cause of thedamage and to takedamage and to take

the requisite action tothe requisite action toprevent a recurrence.prevent a recurrence.


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23291499 bearing failure

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