Influences of Surface Texture on the Friction Characteristics of Powder Metallurgy Clutch Disks

Abstract

Many studies have consistently demonstrated the positive effects of surface texture on the performance of friction couples. Circular dimple textures are made on the flat surfaces of the copper-based powder metallurgy friction disk samples from a multi-disk clutch with five different circular densities. Long-term pin-on-disk sliding experiments under different loads are conducted. Surface morphology analysis is also conducted to evaluate the wear characteristics of the sample disks. Results show that the working load does not significantly affect the coefficient of friction (COF) of the flat surface samples, but there exist significant differences of the COF at different radii with the same rotation speed. Compared with the flat surface samples, the textured samples have a 20–65% decrease of COF under light load conditions but have a more than 30% increase under heavy load conditions. Furthermore, the wear of the textured samples is substantially reduced by more than 19% and 40% respectively. Therefore, the circular dimple texture can significantly enhance the friction and wear performances of the copper-based powder metallurgy friction disks, especially under heavy load working conditions.