Ball Bearings Fatigue Life Calculations and Load Ratings Calculation

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Fatigue life calculations assume the dispersion in life of identical ball bearings operating under identical conditions, a statistical result is obtained for bearing fatigue life. For most calculations, the life is that 90 percent of a group of apparently identical bearings will complete or exceed before the area of spalling reaches predetermined size criterion. If handled, mounted, maintained, lubricated and used in the right way, the life of the bearing will normally reach and even exceed the calculated L10 life.

In the case of single row ball bearings and where a, a2, a3 can be considered equal to one, the equations may be simplified as follows:

Ln = Life in hours

L10 = Life in hours

CE = Extended Basic Dynamic Load Rating Radial Ball bearings Pounds or Newton's

a1 = Life adjustment Factor for reliability (see vendor)

a2 = Life adjustment Factor for Ball Bearing Material

a3 = Life adjustment Factor for Application Conditions

N = Operating Speed (RPM).