Search Results

High friction often involves high wear and power loss. The speed-temperature-dependence of grease lubricated contact ball bearings showed a variety of effects. The test apparatus is an axially-loaded angular contact ball bearing instrumented to measure the frictional torque as well as the transient temperature of the raceway. Effects of friction torque were examined at different speeds, operating temperatures and greases. Torque measurements and transient temperatures were compared for each grease, depending on the operating conditions. After experimental results, the grease formulation under different operation temperatures and different speeds showed significant influence on starting and rotating torques. Moreover the torque showed significant increase during the angular acceleration phase and decreased rapidly after the speed stabilization in all investigated greases.

The wear of thrust 51100 rolling bearings was investigated and their dissipative responses in a bench test rig were associated to their heating, elastic energy of mechanical vibration and Sound Pressure Level [dB], regarding two greases, both from the same supplier, being one with graphite and the other with Molybdenum Disulfide. The samples were commercially acquired and submitted to a normal load of 450±5N and 3100±30 CPM, determined after the screening tests. Four variables were measured: temperature [K], electrical power [W], global velocity vibration [mm/s] and Sound Pressure Level [dB]. After 106 cycles, the tracks were analyzed by Optical Microscopy. The bearings lubricated with the grease with graphite showed different responses in relation to the ones lubricated with MoS2 thrust bearings. The signal of the signatures and the damage morphology are presented and discussed.