Experimental Evaluation of Ball Bearing Performance Using Nanoflake-Blended Greases

Ball bearings encounter grease being pushed aside from the concentrated contact of their rolling elements and races due to the continuous motion of balls. This yields lubricant starvation at the contacts inside the bearings. In this situation, the tribological and vibration performances of ball bearings deteriorate. Therefore, improving the performance behaviors of ball bearings despite starvation is a vital research task. Thus, the objective of this paper was set to explore improving the performance behaviors of a ball bearing employing nanoflake (molybdenum disulfide (MoS2), tungsten disulfide, and hexagonal boron nitride)-blended greases. This paper reports the comparisons of frictional torque, temperature rise, and vibrations of test bearings lubricated with fresh and nanoflake-blended greases. The surfaces of races were examined after the experiments using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). The surface topographies of races and balls were captured using a 3-D profilometer for comparison. The blended greases yielded significant reductions of 17-33, 16-23, and 8-64 % in frictional torque, temperature rise, and vibration, respectively. Surface analyses of races also revealed better tribofilm formation in the presence of MoS2 in grease compared with the other cases.