Influence of Micro-cavity Textured Surface on Tribological Property of Grease Lubricated Spherical Bearing

In order to study the influence of surface texture on tribological properties of grease lubricated spherical bearing, four kinds of specimens were designed and manufactured which have the same surface arithmetic average height and their area densities of micro-cavity were 7%, 10%, 15% and 21% respectively. The surfaces of specimens were measured by Talysurf CCI Lite 3D non-contact surface profiler and characterized with surface parameters defined in ISO25178. With the lubrication of lithium grease, a series of frictional experiments under operating conditions of different loads and velocities were conducted on a modified HDM-20 end-face tribo-tester. The correlations between surface parameters and friction coefficient were studied. Height parameters of arithmetical mean height and kurtosis, functional parameters of material volume in peak zone, void volume in core zone and void volume in valley zone of surface, feature parameter of mean dale volume were chosen to characterize surface topography. The results show that these surface parameters had different effects on friction factor. It is beneficial for the tribological design of surface topography of grease lubricated spherical bearing to characterize surface by the combination of height parameters, functional parameters and feature parameter.