Fatigue Life Evaluation of Small Ball Bearings which Considered Load Distribution of Balls

Abstract

Generally, a fatigue life of rolling bearing can be calculated using a load summing up of external load and deadweight. However, since the load distribution for rolling elements inside the bearing differs considerably due to the design of housing, it is known that each fatigue life differs according to the different load distribution. In this study, the fatigue life was calculated with setting up load distributions for three different kinds of housings by FEM analysis, assuming that the external (radial) load was constant. Consequently, the calculated fatigue life was 0.7 to 1.1 times of the existing rated life which used a condition of zero internal clearance. Though life endurance tests were performed in order to verify this calculated results, flaking cannot be observed with revolutions for ten times longer than the rated life. On the other hand, when the raceway surface (loading area) of the outer ring was observed, it was made sure that the raceway surface fatigue of the outer ring progressed with enlarging load of rolling element.