Abstract: For deep groove ball bearing, the rolling contact model of ball, inner and outer raceways is established. The motion characteristics of rolling bearing are considered in the calculation of fatigue life. A more accurate load distribution calculation model is proposed by considering the number of rolling elements loaded in the ball bearing. Effects of different clearance and speed on load distribution inside the bearing under the same external load are analyzed. For four different motion states of deep groove ball bearing, contact stress variation of points on inner ring, outer ring and ball was computed, and the load sequences are analyzed. The Lundberg-Palmgren (L-P) life model is modified to consider the influences of different motion states on the number of stress cycles in the bearing. The lives of inner race, outer race, rolling elements and the overall bearing are calculated. The lives under different motion states are compared with both the L-P model and the new modified L-P model, which show well agreement under the situation when one of the races is rotating; however, when both of the races are rotating, the lives of bearings calculated with the modified L-P model and the L-P model are quite different from each other.

Key words: deep groove ball bearing, fatigue life, load distribution, load sequence, modified fatigue model