Evaluation of Vibration-Preventive Properties of Lubricating Oils in Wet Friction Plates and Retention of Such Properties Using a Friction Tester

Use of a constant speed friction tester developed to investigate the vibration-preventive properties of oils in wet friction plates afforded better understanding of frictional properties in wet friction. It was found that the dissipation of the friction modifier effect during prolonged use was caused mostly by the change of properties of oils. Test procedures using the tester were validated by testing three automatic transmission fluids with known in-service performance characteristics. Vibrations, caused by the stick-slip between the friction plate and steel plate, were reproduced on the tester by varying its rigidity. The tester is expected to be effective in countering actual problems.