Performance Evaluation of Automotive Wheel Bearing Greases.

The lubrication characteristics of five candidate greases for use in non-driven wheel bearings of U.S. Army vehicles have been experimentally evaluated. The lubrication capability of each grease was established in a laboratory environment on a machine designed to simulate the general configuration of an automotive front wheel bearing hub under highly accelerated test conditions designed to precipitate a lubricant related bearing failure. A pair of tapered roller bearings of the size typically used in an automotive application were run at an inner ring speed of 800 rpm, equivalent to 105 kph, and loaded under a continuous radial force equivalent to 150 of the vehicle curb weight and cyclic axial cornering force equal to 30 of the radial force applied for 1-12 minutes out of every 5. The ambient environment was also artificially elevated to 394 k 121 C to further accelerate the test cycle. Each lubricant was rated on the basis of the experimental life achieved, the condition of the residual grease within the bearings and the condition of contact surfaces. The performance of these greases was subsequently compared to that of greases tested in previous programs.