Experimental study on reciprocation rolling-sliding contact with spin

This paper describes the development of a novel test rig to study mechanisms of surface failures and lives of constant velocity universal joints, CVJs, which are used in drive lines of automobiles. In order to simulate the rolling contact with slip and spin between a ball and inner and outer races of a CVJ, the test rig employed a crank mechanism that allowed a ball to make reciprocal linear and rotational motion relative to upper and lower specimens. Preliminary tests with greases showed that, by changing the test conditions, the rig was able to simulate various failure modes that occur in CVJs. They included the flaking by surface-initiated cracks, the flaking caused by sub-surface initiated cracks with structural changes including white etching areas, and the wear without flaking. Details of the failure processes were examined by the observation of track surfaces and cross sections. The results confirmed that the crack propagation depended on the driver-follower relationship between the specimens.