Abstract: The self-lubricating radial spherical plain bearings with steel/PTFE fabric friction pairs are taken as the research objects, studying from the wear mechanisms, basing on the combined wear theory and the stability characteristic of the linear wear rate in stage of steady wear, new analytical life model formulas for such bearings are derived from the movement analysis, contact and velocity analysis, force analysis, wear loss analysis under combined swivel and tilt motion condition. With the formulas, the bearing wear lives respectively for swivel motion, tilt motion, and combined swivel and tilt motion can be obtained, the calculation methods are also put forward. Through the numerical examples, the life ratios close to the existing theories results and the experimental results for the three kinds of motions under different working conditions are obtained, the results differ more smaller with the theoretical results especially for the combined motion, the relative errors are less than 6%. New life model provides a new life calculation method for the self-lubricating radial spherical plain bearings and can make up for the deficiencies of the existing life formulas which mostly only consider swivel condition.

Key words: combined swing and tilt motion, combined wear theory, self-lubricating radial spherical plain bearing, swivel motion, tilt motion, wear life