Thermal contact resistance between balls and rings of a bearing under axial, radial, and combined loads

The thermal contact resistance between the balls and the inner and outer rings of a space-use deep groove ball bearing is investigated assuming that heat transfer between smooth contacting elements occurs through the elastic contact areas. It is also assumed that the stationary bearing sustains axial, radial, or combined loads under a steady-state temperature condition. The shapes and sizes of the contact areas are calculated using the Hertzian theory. In particular, the contact force for the axial load is determined with careful consideration of the change in the contact angle induced by elastic deformation at the contact area. The correlation between the experimental data and the calculated values confirms the validity of the prediction method for the thermal contact resistances between the elements of a dry bearing with a surface roughness of less than 0.5 x 10~ m under the mean temperature of less than 353 K, and temperature differences across the rings of less than 35 K.