Aballbearingisatypeofrolling-elementbearingthatusesballstomaintaintheseparationbetweenthebearingraces.
Thepurposeofaballbearingistoreducerotationalfrictionandsupportradialandaxialloads.
Itachievesthisbyusingatleasttworacestocontaintheballsandtransmittheloadsthroughtheballs.
Inmostapplications, oneraceisstationaryandtheotherisattachedtotherotatingassembly (fx ahuborshaft).
Asoneofthebearingracesrotatesitcausestheballstorotateaswell.Becausetheballsarerollingtheyhaveamuchlowercoefficientoffrictionthaniftwoflatsurfaceswereslidingagainsteachother.
Ballbearingstendtohavelowerloadcapacityfortheirsizethanotherkindsofrolling-elementbearingsduetothesmallercontactareabetweentheballsandraces.
Men theycantoleratesomemisalignmentoftheinnerandouterraces.
