Tribology and Lubrication Requirements of Constant Velocity Joints

Ball and Tripod constant velocity joints are used in the majority of today's automobiles. The tribology of both types is complex. The low speed variable sliding and rolling motions with sinusoidal variation of amplitude and track surface conditions having typical Ra values of 0.4 to 4μm give rise to low λ-ratios. Contact conformities are above the level at which Hertz contact mechanics can normally be applied.

These factors, plus the introduction of new joints, demands from downsizing and the search for improved refinement has lead to the development of new high-performance greases to provide effective, filled-for-life lubrication.