Influence of an outer ring end offset on the service life and eccentric wear defects of self-lubricating spherical plain bearings

Abstract

Improving the service life of self-lubricating spherical plain bearings is important due to the wear failure of the self-lubricating layer is considered as the primary reason for their service life decreases. Currently, there remains a lack of research on the influence of the forming accuracy of radial symmetry on bearing service life. This study investigated the relationship between the forming accuracy of self-lubricating spherical plain bearings and bearings’ life, by proposing the concept of the outer ring end offset. Based on the influence of the offset on the contact stress and strain of the bearing, the range of reasonable offset was analyzed. The correctness of the range of offset was verified by bearing friction tests, and the wear mechanism of the bearing eccentric wear phenomena was described. Results show that the forming accuracy of the outer ring is an essential factor that affects bearing service life. The outer ring end offset can be used as a key indicator of forming accuracy. Considering the GE15DE1TK self-lubricating spherical plain bearing as an example, the outer ring end offset with an over-extrusion bearing should be less than 0.05 mm. However, the required offset for an insufficient-extrusion bearing does not easily produce eccentric wear defects even with an offset of 0.08 mm. This paper provides a new idea and indicator for improving the service life of self-lubricating spherical plain bearings.