Lubricant seepage behavior of porous polyimide cage materials under sliding contact loading

Porous polyimide is a high-performance self-lubricating material widely used as an oil storage medium in aerospace bearing cages. This paper investigates the transient seepage behavior of oil-containing porous cage materials under sliding contact loading. It is found that there are multiple seepage regions within porous media during the seepage process, which interact to facilitate the inflow and outflow of lubricant. The extrusion effect plays a critical role in determining seepage behavior, while the centrifugal effect has a lesser impact on surface seepage rate and lubricant outflow in porous media. The extrusion effect also contributes to the formation of the “tribological rehydration” phenomenon. This study provides a theoretical foundation for understanding the continuous oil supply mechanism in aerospace bearing cage materials.