Relationship between statistical parameters of lip surface microtopography and coefficient of friction of radial shaft seals

The influence of lip surface topography on lubrication of radial shaft seals was studied experimentally. Lip surface profiles taken in the direction of sliding for four different lip materials were analyzed using conventional surface texture parameters. The parameters from the four categories including height, spatial, hybrid and functional parameters, for twelve profiles obtained at four circumferential positions on each specimen were calculated. Distribution and median of each parameter were compared among the materials. Each parameter had a different distribution depending on the materials. The median of each parameter was compared with the coefficient of friction. It was found that density of peaks and correlation distance correlated well with the coefficient of friction in the fully flooded conditions. This is in agreement with the theoretical analysis of hydrodynamic lubrication using deterministic models of surface topography.