Friction Coefficient Variation between Brake Pad and Disc Rotor with Moisture

- Variation Mechanism Focusing on Wear Debris Behavior -

Abstract

This paper deals with the friction coefficient μ variation of a disc brake system with moisture. In our previous studies, it was experimentally found that wet wear debris between the brake pad and the disc rotor affect μ variation and μ of the wet wear debris increases with decreasing their moisture content. Based on the experimental results, we propose a hypothesis that clusters composed of the wet wear debris induce μ variation when the clusters stand between friction surfaces. In this paper, for supporting the hypothesis, we tested the shear properties with different kinds of liquid, and simulated the wear debris behavior under wet condition between friction surfaces using the discrete element method. From these results, we clarified that the wet wear debris made the clusters due to the capillary force, and their behavior contributed the increase of μ.