The Effect of Retainer Geometry on the Stability of Ball Bearings

Low-frequency torque variations in the support bearings of the Intelsat IV communications satellite were found large enough to cause significant spacecraft pointing error. Laboratory and computer studies indicated that the geometry of the (phenolic) retainers was a major contributor to the instability of the bearings. Two parameters were found to be critical: the ball pocket cone angle and cone depth. For these two parameters, the computer analysis predicted dimensional tolerances which would result in stable retainers. In dynamic torque tests under a variety of conditions, retainers within the computer-predicted range were found to be stable. Several retainers beyond these dimensional tolerances exhibited instability. Presented at the 30th Annual Meeting in Atlanta, Georgia, May 5–8, 1975