Increase of Traction Coefficient due to Microtexture (1st Repor, Effect of Orientation in Microtexture)

Abstract

Improving the traction coefficient of a traction drive system is a key factor in obtaining a smaller, lighter unit and also greater torque capacity. This study focused on the microtexture of the rolling elements, and effect of orientation in microtexture was examined with the aim of improving the traction coefficient in the viscous region. Three textures-dimple, transverse and longitudinal-were examined using a 4-roller tester that enabled tests to be conducted under high pressure and high rolling speed. As a result, it was found that the longitudinal surface texture is the best for improving the traction coefficient. The results obtained with EHL analysis showed that only the surface texture with longitudinal grooves improved the traction coefficient, just as in the tests conducted with the 4-roller tester.