Effects of Surface Dimples on Friction Coefficient of Reciprocating Model Lip Seals

In order to investigate the effect of surface dimples on the friction coefficient of a rod seal, model lip seals including six patterns of dimples and plane one were used to investigate the effect on friction coefficients. The differences of the friction coefficients between a plane model and models with dimples, and the effect of the specification of dimples are discussed. Furthermore, in order to explain the mechanism of the effect of dimples, the processes of oil film formation on the contact surface have been observed by an optical interferometric method. It was found that the effects of dimples on the friction coefficient could be explained by the oil film formation on the contact surface.