Optical Measurement of Roller Slip, Tilt, and Skew in a Spherical Roller Bearing

Abstract In this study, a novel test rig was designed and developed to investigate roller slip, tilt, and skew in a spherical roller bearing (SRB). The test rig utilized a double-row 22313 SRB and was designed to allow for direct visual access to each row. A high-speed camera was used to capture the motion and angular position of the various rollers as they traversed the bearing. Successive frames captured from the videos were analyzed to determine roller slip and the SRB load zone. Roller tilt and skew angles were also measured by inserting a nearly weightless pin into the center of a roller. In a similar manner, high-speed videography was used to assess the tilt and skew of the roller for a complete revolution of the roller around the inner race of the SRB. The dynamic behavior of the rollers was then corroborated with a previously developed SRB dynamic bearing model (DBM). The experimental and analytical results indicate that the roller tilt angle increases with axial load, remains constant with speed, and decreases with increasing radial load when the roller is located in the load zone. Further, roller skew in the load zone increases with axial load and shaft speed; however, it decreases with the radial load. The results indicate that when the radial-to-axial load ratio is greater than 4, roller tilt and skew are minimized. Due to roller intermittent slip and roller-cage pocket collision in the unload zone, tilt and skew become chaotic. The magnitude of the tilt and skew in the unload zone is directly related to the roller-race and roller-cage pocket clearances, respectively.