Effect of ball off size on fatigue life of deep groove ball bearing

Aiming at the inevitable machining errors in manufacturing processing, a modified life model, which is composed of regular Lundberg-Plamgren life model, Miner´s linear cumulative damage theory and the concept of equivalent load state, for deep groove ball bearing was presented. Based on the proposed model, the effects of ball off size under different working conditions were investigated. In combination with machining error distribution theory, statistical analysis of bearing life was conducted. At last, 16008 deep groove ball bearing was selected to illustrate the modified life model. Through numerical calculation, the following conclusions can be drawn : 1) The life factors are normally distributed when the ball off sizes have normal distribution; 2) With the increasing of external load, the effect of ball off size on bearing fatigue life is weakened; 3) The effect of ball off size on bearing fatigue life is most obvious when bearing operates in a small negative radial clearance.