Mechanism of dent initiated flaking and bearing life enhancement technology under contaminated lubrication condition: Part I: Effect of tangential force on dent initiated flaking

In this paper, we have clarified experimentally the mechanism of dent initiated flaking as observed in rolling element bearings operating under contaminated lubrication conditions. A characteristic of dent initiated flaking is the initiation of cracks on the trailing edge of dents relative to the rolling direction. Based on the results of twin-disk testing and ball-on-rod rolling contact fatigue (RCF) testing conducted, we have confirmed that the crack initiation at the edge of a dent is strong influenced by the tangential force. The tangential force leads to the generation of a large tensile stress at the trailing edge of dents, which in turn leads to crack initiation.