MS Thesis Presentation by Daniel Osorno
Tuesday, August 23, 2005

(Dr. Steven Danyluk, Chair)

"Rolling Element Skew Measurement in a Spherical Roller Bearing Utilizing a CPD Probe"


This thesis incorporates an array of Contact Potential Difference (CPD) sensors to measure and monitor the degree of skew in the rolling elements of a spherical roller bearing. Skewing is the motion of a roller as it turns about an axis normal to the roller race interface. Roller skew is generated as part of the kinematic effects of roller bearings. Skew monitoring is important for bearing design as it is an indirect measure of bearing life.

For the purpose of this thesis, roller skew was measured utilizing multiple pairs of CPD probes located around the bearing's outer raceway at varying points of the loading zone. These CPD probes are not in direct contact with the rollers, but in close proximity to their surface (through the bearing outer ring). The skew angle measured is related to different operating conditions such as applied load, shaft speed, and lubrication.

The pair of CPD probes detected a signal as the roller surface passed by and the phase difference between the two distinct signals measured the skew angles in the range of 0.016° to 1.10°. The shaft is rotated both clockwise and counterclockwise to capture any probe misalignment which was in the range of 0.5° up to 2.0° . This thesis also provides a model for the probe signal as a spherical roller surface passes the probe surface.