The friction and wear behaviors of polyimide bearing retainer under point-contact condition

Purpose Random point-contact between the space bearing retainer and the rolling elements may cause wear of the space bearing retainer. The paper aims to clarify the friction and wear behaviors of polyimide bearing retainer under point-contact condition. Design/methodology/approach Space bearing retainers were cut into flat specimens and the tribological behaviors of the specimens were studied under point-contact condition using a friction and wear testing machine. Different sliding velocities and normal loads were used to simulate the running state of space bearing retainer. The wear behaviors of the space bearing retainer were analyzed by SEM and white light interferometer. Findings The friction coefficient of the polyimide composites decreased with increase in sliding velocity from 1 to 5 mm/s. Moreover, with increase in sliding velocity and normal load, the wear rate of the polyimide composites decreased and increased, respectively. Moreover, the wear behaviors of the polyimide composites were mainly determined by the combined actions of ploughing friction and adhesive friction. The lubricating properties of transfer film and wear debris were limited under point-contact condition. Practical implications The paper includes implications for the understanding of the wear mechanism of the polyimide composites space bearing retainer under point-contact condition and then to optimize space bearing retainer materials further. Originality/value Under point-contact condition, wear debris can hardly participate in the friction process because of limited contact area. Consequently, the wear debris has limited impact on the wear process to decrease the friction and wear. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-01-2020-0017/