Abstract:

Taking the precision ball bearings in spacecraft mechanism as a research object, the wear law of space precision bearings is investigated by considering axis preload and assembly situation deviation. Based on the statics of the rolling bearing and the Archard wear model, wear condition is analyzed at each angular position of inner ring, and position of lubrication failure caused by wear of lubrication film is predicted. Firstly, the static equilibrium equation of bearing is established, the relationship between the bearing axial load and axial displacement is obtained, and the relationship of radial assembly variation and the introduced radial load is obtained as well. Then, by using the Archard wear model at the same time combining the force and the movement of ball in contact regional, the wear of the bearing is analyzed in different angle position. In addition, the evolution law of wear with the axial force, radial force and wear time is analyzed at each angle position, respectively. The results showed that: when axial force alone is considered, the wear of each angle position of the inner ring is the same. What’s more, there exists linear relationship between wear depth and axial force. However, internal radial force changes exponentially with the radial position deviation when axial preload and assembly situation deviation are comprehensively considered. Radial position deviation leads to great difference in wear depth at each angular position of the inner ring. When radial force increases, the wear near the deviation direction increases while that away from the deviation direction weakens. With the wear time coursing, the difference of wear depth at each position keeps widening. The difference in contact angle caused by radial deviation is very small while that in radial force is large at different angular positions.

Key words: assembly situation deviation, preload, wear, space bearing