Effect of Grease Viscosity on Channeling Properties of Ball Bearings

Abstract

Grease-lubricated rolling bearings transition from the churning phase to the channeling phase. This transition property affects grease life and torque properties. Therefore, the relationship between grease yield stress and grease degradation during operation, which affects this transition, has been investigated. However, there have been few studies on grease flow that affects the transition. In this study, the mechanism of grease reduction on the races was investigated for small bearings operated at low speeds, where thermal degradation and softening of the grease are less likely to occur. It was inferred that the grease transfer to the cage affects the channeling transition and that the amount of transfer varies depending on the initial grease viscosity. These findings can be applied to grease composition and cage design and are useful in providing bearings with excellent low-torque characteristics, such as in industrial motor applications.