Experimental Studies on Friction Processes in Sliding Thrust Bearings

Abstract

A technique for conducting experiments on determining wear features for thrust slide bearings is presented. The friction coefficient depending on the load and on the rotation velocity of the samples, on the changes in the wear weight fraction, and on the surface roughness parameters are determined. The effect of thickness, propagation, and interaction on the oil film formed in a hydrodynamic friction mode on the wear of friction pairs is considered. An instrumental support of the experiment is described, the results and conclusions are presented. It is noted that the local maximum of the friction coefficient is reached at approximately 900 rpm for all the samples and, for each load level, a corresponding minimum of friction coefficient is observed, which increases with increasing rotation velocity. In the course of testing, the minimum values of friction coefficient have been observed in the ranges of 550–650 rpm and 1050–1150 rpm. For the used testing mode, the smallest change in the surface roughness of the samples amounted to R_a = 0.46–045 μm for steel samples and R_a = 0.75–0.89 μm for bronze samples, respectively. These roughness values have been subjected to changes to a lesser extent, being close to the equilibrium roughness in the course of the testing. It should be noted that the greatest weight wear level of the samples occurs under running-in, and, when equilibrium roughness and the minimum friction coefficient have been reached, the sample wear level exhibits a decrease. In addition, upon the experiments, the distribution of the hydrodynamic oil film pressure over the surfaces of the samples was revealed based on the wear scars in the outer circuit, and its high-pressure belt was expanded in the circumferential direction.