Performance improvement of a radial ball bearing using a micro-groove on stationary outer race

For achieving improved lubrication in a radial ball bearing (BB1B 420206), a circumferential micro-groove inside the stationary outer race has been conceived based on finite element analysis to facilitate the availability of grease and to reduce the stresses at the contacts and it has been fabricated to conduct the experiments. To understand the effect of this micro-groove filled with grease on the film formation, frictional torque, and bearing dynamics, experiments were performed for measuring these variables at different operating parameters ( p H = 0.35–1.2 GPa; speed = 1.4–4.2 m/s). Capacitance based approach, load cell, and miniature accelerometer have been employed to measure the film thickness, frictional load and vibrations, respectively. The results achieved with bearings with micro-groove on outer races have been compared with bearings having the conventional races at the identical operating parameters. Reductions of 14%–41% in vibrations, up to 11.2% increase in film thickness (i.e. 11% reduction in the capacitance), and in the range of 15%–30% reduction in the frictional torque have been obtained as compared to conventional bearing cases.