Investigation on frictional characteristic of deep-groove ball bearings subjected to radial loads

Abstract

Radial load is of great significant influence on friction characteristic and fatigue life of rolling bearings. A frictional torque analysis was performed on the radially loaded SKF-6205 deep-groove ball bearings. The frictional torque formula was proposed as the sum of the frictional torques caused by elastic hysteresis, elastic hydrodynamic lubrication, differential slip, spinning friction of balls, friction between the balls and the cage pockets, and friction between the cages and the guiding lands. The experiments were carried out with the bearing with lubrication and the other one without lubrication under different radial loads and rotational speeds. In order to avoid the frictional torque measurement errors caused by the unequal length of arms, a positive-negative test method is employed to test bearing frictional torque. The experimental results showed that the frictional torque caused by radial loads played a leading role in all the frictional torque components of the bearing. Ultimately, a special theoretical model of frictional torque for deep-groove ball bearings was verified through comparing with the experimental results and SKF torque model. A reasonable correlation exists between the experiment results and the theoretical model.