Effect of surface texture on the frictional properties of grease lubricated spherical plain bearings under reciprocating swing conditions

Surface texturing is a widely used method to improve the tribological performance of the mechanical systems. To introduce the surface texture into the mechanical components, this study experimentally examined the frictional behaviors of grease lubricated spherical plain bearings under mixed lubrication conditions on an electro-hydraulic servo tribological test rig. The effects of the surface texture parameters and roughness parameters on the frictional properties of bearings were investigated. The results showed that higher dimple depths and lower dimple densities would result in a distinct improvement on the friction coefficients. A maximum reduction of 55% was gained for the textured sample under running conditions compared with the untextured one. In addition, the surface roughness parameters also influence the frictional behaviors. In the high load conditions, the friction coefficient decreases while the S sk value gets more negative, even though the S a value is much higher. On the other hand, in the low load conditions, when the value of S sk varies between −5 and −1, the influence of the value of S a on the friction coefficient becomes obvious, a higher S a value results in a higher friction coefficient.