The Influence of Finish Treatment on the Service Life of the Bearing

Abstract

Roughness in rolling bearings plays a very important role. Improving the reliability of rubbing parts of equipment is an urgent task. Finishing, superfinishing and laping were used as finishing operations. (Research purpose) The research purpose is in investigating the effect of various finishing operations on the durability of the needle bearing of the cardan joint. (Materials and methods) Needle bearings of the GPP 704702K model (with a nominal dynamic load capacity of 160 kilonewtons) were studied. Tests were carried out on a test rig for four cups and spikes of bearings made of 20KhVG high-carbon chromium bearing steel. The article presents the results of measuring the roughness in the axial direction of the spike and the working surface of the bearing, carried out using a T1000 Basic portable semi-automatic device for measuring surface roughness of first accuracy class. (Results and discussion) As the roughness of the raceway increases, the bearing life decreases. It has been noted a difference in the increasing bearing temperature depending on the roughness of the raceway surface and finishing methods. The sample subjected to superfinishing or laping had the smallest temperature increase and there was a tendency to increase the bearing temperature as the surface roughness increased. (Conclusions) The roughness of the raceway has a close relationship with the service life, with a decrease in roughness, the service life increases by about 1.8 times. It was found that superfinishing or lapping with a sand paper after finishing to a certain roughness nmach = 3 micrometers by grinding is more effective than processing a smooth surface by grinding alone. It was found that when the surface roughness of the raceway decreases, the bearing temperature decreases.