Effect of grease grades on the tribological and vibrational behaviours of a radial ball bearing: Conventional vs. micro-grooved outer races

Abstract

Comparative tribo-dynamic studies of radial ball bearings possessing micro-grooved and conventional outer races, employing three different grades of lithium soap-based greases (NLGI grade 000, 2 and 3), are presented in this paper. This research has been conducted to explore and understand the effectiveness of grease grades on the performance parameters in the presence of a circumferential micro-groove on the outer race as compared to conventional case. Indication of lubricating film thickness formation (in terms of capacitance), frictional torque, vibrations, and rise in temperature have been assessed for the conventional and micro-grooved outer race bearings at different operating parameters (p_H = 0.9 to 1.4 GPa; speed = 1.4 to 4.2 m/s). The micro-grooved bearings (MB) provided the indication of better lubricating film formation in terms of capacitance reduction in the range of 11–19% as compared to the conventional bearing (CB) cases. However, the reduction in frictional torque, vibration and rise in temperature magnitudes have been found in the range of 14–26%, 6–23%, and 10–24% respectively, as compared to the CB cases.