Ball Bearings Fatigue Life Calculations and Load Ratings Calculation

Bearings Application Knowledge Menu

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.

Open Bearing Fatigue Life Calculator #1

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:

Open Bearing Fatigue Life Calculator #2

L_n = Life in hours

L₁₀ = Life in hours

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

f_B = Dynamic Load rating Adjustment factor for Number of Adjacently Mounted Bearings

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).

P = Equivalent Radial Load on Bearing Pounds or Newton's