An Experimental Set Up Development for Brake Squeal Basic Research

The vehicle requires high brake performance and mass reduction of disc brake for vehicle fuel economy. Then disc brake will be designed by downsizing of disc and high friction coefficient pad materials. It is well known that disc brake squeal is frequently caused by high friction coefficient pad materials. Disc brake squeal is caused by dynamic unstable system under disturbance of friction force variation. Today, disc brake squeal comes to be simulated by FEA, but it is very difficult to put so many dynamic unstable solutions into stable solutions. Therefore it is very important to make it clear the influence of friction force variation. This paper describes the development of experimental set up for disc brake squeal basic research. First, the equation of motion in low-frequency disc brake squeal around 2 kHz is derived. Second, the increase of kinetic energy per 1 cycle in minute vibration is derived, which represents the influence of coupled vibration between out of plane vibration and in-plane vibration in disc and pads with caliper. Based on this analysis, the experimental set up with pad-caliper consist of small pad fixed on cantilever is designed, and its experimental results of low-frequency disc brake squeal are shown in this paper.