Measurements of EHL film temperature between sapphire disk and longitudinally grooved steel ball under high slip ratio conditions

This paper describes results of temperature measurements using longitudinally grooved steel balls and a sapphire disk under high slip EHL conditions. The authors measured the temperatures of both the sliding surfaces and the oil film, furthermore, estimated the temperature profiles across the oil film with experimental results. The experimental results show that the temperature of the ball surface with textured balls increase considerably in compared with that with a flat surface ball. The shape of the temperature distribution of both the surface and the oil film have higher value at the land zones and lower one at the grooved ones. The film thickness with increasing slip ratios decreases while previous results have indicated a constant thickness. The decrease of the thickness can be explained by the viscosity wedge action due to the temperature variations across the oil film.