Improving the tribological properties of radial shaft seal countersurfaces using experimental micro peening and classical shot peening processes

Abstract

Due to high requirements on the shaft counter-surface of radial shaft seals, the state of the art manufacturing process typically consists of pre-turning, case hardening and plunge grinding. Investigations of alternative surface finishing processes such as shot peening or rolling have shown a significant reduction of friction in the sealing contact compared to ground surfaces. In this paper, a new surface treatment process for such shaft seal counter surfaces is investigated and compared to shot peened and conventionally plunge ground surfaces regarding friction, shaft wear, sealing function and reverse pumping. The process is a modification of a cold spraying process, where microscale particles are used as shot material, which are intended to dent the surface and create small hydrodynamically active structures without sticking to the surface and can therefore be understood as micro shot peening of the surface. Results show a significant reduction in wear and friction compared to ground surfaces.