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The word BEARING The word BEARING derived from the word BEAR derived from the word BEAR which means TO SUPPORTwhich means TO SUPPORT

Which is what bearings do ...Which is what bearings do ...SUPPORT and GUIDE SUPPORT and GUIDE other machine elements other machine elements

The ball bearings in thisThe ball bearings in thiselectric motor supportelectric motor supportand guide the rotorand guide the rotor

Why bearings?Why bearings?What is a Rolling Bearing ?What is a Rolling Bearing ?What is a Rolling Bearing ?What is a Rolling Bearing ?

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Two types?Two types?

ANTI-FRICTION bearings so called because theyhave a lower coefficient offriction (0.00015 - 0.004) ascompared to that of journalbearings (0.008 to 0.020)

SLIDING or BUSH or JOURNAL bearings

ROLLING or ANTIFRICTION bearingsand

The lower coefficient offriction is achieved bythe super-finishing ofraceways

What is a Rolling Bearing ?What is a Rolling Bearing ?What is a Rolling Bearing ?What is a Rolling Bearing ?

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Plain bearings:sliding friction

Rolling bearings:rolling friction

Sliding Friction

Rolling Friction

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JOURNAL BEARINGSJOURNAL BEARINGS

Journal bearingJournal bearing

LubricantLubricant

TheThe shaftshaft whichwhich supportssupports thethe loadload isismountedmounted onon rollingrolling bearingsbearings whosewhoserollingrolling elementselements transmittransmit thethe loadloadrollroll throughthrough hardenedhardened ringsrings

ROLLING BEARINGSROLLING BEARINGS

The shaft which supports the loadThe shaft which supports the loadruns in a lubricated bushruns in a lubricated bush

Rolling elementRolling element

HardenedHardenedinner ringinner ring

HardenedHardenedouter ringouter ring

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1.1. Inner RingInner Ring2.2. Outer RingOuter Ring3.3. Rolling ElementsRolling Elements4.4. CageCage

Rolling Bearing ComponentsRolling Bearing Components

FullFull complementcomplement CylindricalCylindrical andandNeedleNeedle RollerRoller BearingsBearings withoutwithoutcagescages

Exceptions to the rule ...

CylindricalCylindrical RollerRoller BearingsBearings withoutwithoutinnerinner ringsrings forfor directdirect shaftshaft runningrunningarrangementsarrangements

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Pure Radial Load

Load ConditionsLoad ConditionsLoad ConditionsLoad Conditions

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Pure Axial Load

Load ConditionsLoad ConditionsLoad ConditionsLoad Conditions

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Combined LoadingRadial + Axial Load

Load ConditionsLoad ConditionsLoad ConditionsLoad Conditions

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The Load Zone and Contact Points

When a bearing is supporting a radial load,the load is distributed through only a portionof the bearingapproximately one-third(1/3)at any given time. This area supportingthe load is called the bearing load zone.

Every point or surface where loads aresupported by the bearing are load carryingcontact points or surfaces. These include theouter Ring O.D.,inner Ring I.D., the adjacentsurfaces that form right angles to each other,raceways and rolling elements.

Load ZoneLoad ZoneLoad ZoneLoad Zone

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Roller and Ball Raceway ContactRoller and Ball Raceway ContactRoller and Ball Raceway ContactRoller and Ball Raceway Contact

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RollingRolling bearingsbearings areare classifiedclassified asas BallBallBearingsBearings andand RollerRoller BearingsBearingsdependingdepending onon thethe shapeshape ofof theirtheirrollingrolling elementselements

Classification of Rolling Bearing ?Classification of Rolling Bearing ?Classification of Rolling Bearing ?Classification of Rolling Bearing ?

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Deep GrooveDeep GrooveBall BearingBall Bearing

Single RowSingle RowAngular ContactAngular ContactBall BearingBall Bearing

Four PointFour PointContactContact

Ball BearingBall BearingSelf AligningSelf AligningBall BearingBall Bearing

Double RowDouble RowAngularAngular

Contact BallContact BallBall BearingBall Bearing

Classification of Ball BearingsClassification of Ball BearingsClassification of Ball BearingsClassification of Ball Bearings

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Single RowSingle RowCylindricalCylindrical

Roller BearingRoller BearingBarrel RollerBarrel Roller

BearingBearing

Double RowDouble RowCylindricalCylindrical

Roller BearingRoller BearingTapered RollerTapered Roller

BearingBearingSpherical RollerSpherical Roller

BearingBearing

Classification of Roller BearingsClassification of Roller BearingsClassification of Roller BearingsClassification of Roller Bearings

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Classification of Thrust Ball BearingsClassification of Thrust Ball BearingsClassification of Thrust Ball BearingsClassification of Thrust Ball Bearings

Single Direction Thrust Ball BearingSingle Direction Thrust Ball Bearing

Double Direction Thrust Ball BearingDouble Direction Thrust Ball Bearing

Double Row Angular Contact Thrust Ball BearingDouble Row Angular Contact Thrust Ball Bearing

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Classification of Thrust Roller BearingsClassification of Thrust Roller BearingsClassification of Thrust Roller BearingsClassification of Thrust Roller Bearings

Spherical Roller Thrust BearingSpherical Roller Thrust Bearing

Cylindrical Roller Thrust Ball BearingCylindrical Roller Thrust Ball Bearing

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TheThe rollingrolling elementselements transmittransmit loadsloads fromfrom oneone bearingbearing ringring toto thethe otherother ininthethe directiondirection ofof thethe contactcontact lineslines.. TheThe contactcontact angleangle aa isis thethe angleangle formedformedbyby thethe contactcontact lineslines andand thethe radialradial planeplane ofof thethe bearingbearing..

Ball bearings and roller bearings with symmetrical rolling elements haveidentical contact angles at their inner rings and outer rings. In rollerbearings with asymmetrical rollers the contact angles at the inner ringsand outer rings are not identical.

Contact angleContact angleContact angleContact angle

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TheThe pressurepressure conecone apexapex isis thatthat pointpoint onon thethe bearingbearing axisaxis wherewhere thethecontactcontact lineslines ofof anan angularangular contactcontact bearing,bearing, ii..ee anan angularangular contactcontact ballballbearing,bearing, aa taperedtapered rollerroller bearingbearing oror aa sphericalspherical rollerroller thrustthrust bearingbearingintersectintersect.. TheThe contactcontact lineslines areare generatricesgeneratrices ofof thethe pressurepressure conecone apexapex..

Pressure Cone ApexPressure Cone ApexPressure Cone ApexPressure Cone Apex

InIn angularangular contactcontact bearingsbearings thethe externalexternal forcesforces FF act,act, notnot atat thethe bearingbearingcentre,centre, butbut atat thethe pressurepressure conecone apexapex.. ThisThis factfact hashas toto bebe takentaken intointoaccountaccount whenwhen calculatingcalculating thethe equivalentequivalent dynamicdynamic loadload PP andand thetheequivalentequivalent staticstatic loadload PP00 ..

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Misalignment properties of BearingsMisalignment properties of BearingsMisalignment properties of BearingsMisalignment properties of Bearings