Effect of Stress during Press-Fitting on Tribological Behavior of Self-Lubricating Composite Liners in Spherical Plain Bearings

Self-lubricating spherical plain bearings are widely used in industry due to their high load capacity, excellent self-lubrication performance and superior impact resistance. The composite made of PTFE/Nomex fabrics and phenolic resin is selected as self-lubricating liners because of the great tribological properties. In this study, the effect of stress during press-fitting process on the tribological behavior of the composite liners in bearings was investigated. Five levels of stresses within a range of 0MPa~680MPa were firstly applied by upsetting process, and then ball-on-disk friction tests were conducted to evaluate the tribological properties. The variation of measured friction coefficient over testing time under different stresses was measured, and the microscopic surface morphology before and after friction tests was observed. Results show that the stress generated during the press-fitting process increases the friction coefficient, while decreases the fluctuation of friction coefficient. In addition, the fluctuation amplitude of the friction coefficients introduced by stress reaches 5.6%.