Characterization of abnormal lubricant film pressure distribution mechanisms in pure sliding AISI52100 ball bearing contacts using sliding contact fatigue distribution and wear behaviour

Ball bearings are a critical component of transmission systems whose operation depends on efficient lubrication. Moving surfaces in ball bearings are typically manufactured from AISI52100 martensitic steel material. During operation, a critical role of the lubricant is to generate film- pressure, which creates film thickness and separates the moving surfaces. There is lack of knowledge regarding abnormal film-pressure generating mechanisms occurring in ball bearings during pure sliding motions. In this study, sliding contact fatigue and wear behaviour are used to characterise abnormal film-pressure distribution behaviours, which reveal the appearance of abnormal film pressure generating mechanisms in pure sliding AISI5200 ball bearing contacts. A set of pure sliding experiments were conducted using a wear test machine with a ball bearing configuration. Abnormal plastic deformation and wear behaviour on the worm bearing surfaces indicate the appearance of an abnormal collaboration between two film pressure generating mechanisms i.e., the viscosity wedge effect (VWE) and the squeeze effect. The VWE is described where abnormal surface deformation is observed, and the squeeze effect, where deformation is influenced by the change in sliding speed. These findings reveal, for the first time, the domain of action of each effect in the ball bearing contact area.