Influence of Surface Roughness Topography on Properties of Water-Lubricated Polymer Bearings: Experimental Research

Abstract

Surface smoothness of journal and bushing has significant influence on properties of sliding bearings. Relevant literature contains a number of theoretical works connected with the subject of surface roughness pattern and height. Calculations based on various models indicate that the structure of sliding surface influences bearing's hydrodynamic properties. One of the main conclusions is that roughness transversal to the sliding direction can increase hydrodynamic capacity of a bearing (H. Christensen and K. Tonder, 1973, Journal of Lubrication Technology, Vol. 4, pp 166–172). In bearings lubricated by a low-viscosity liquid such as water, the influence of roughness is of particular importance. This is due to low hydrodynamic film thickness and the resulting limited hydrodynamic capacity of these types of bearings. In fact, these are the reasons for deciding to conduct experimental research aimed at verifying the influence of roughness pattern on bearing properties. Research conducted for a selected group of polymer materials demonstrates strong influence of roughness height on movement resistance and working properties of bearings. No significant influence of roughness pattern on working parameters was observed. Furthermore, the running-in process for this type of bearing material is rapid. The sliding surface becomes smoothed out in just a few hours of work, significantly reducing all of the coefficients of friction.