In this paper, friction behavior of brake friction material was experimentally examined to investigate the correlation between groan noise and friction coefficient of brake pad. Pin-on-disk type brake dynamometer and experiment modes were developed and 10 brake pads with different relative amount of ingredient were tested by using this friction tester. By comparing the test results of each brake pad with results of vehicle test, the correlation between groan noise and friction coefficient of brake pad was investigated.
The result showed that the tendency of groan noise became higher as the difference between maximum friction coefficient in acceleration and friction coefficient in constant speed after acceleration became larger. Also the difference between maximum static friction coefficient and kinetic friction coefficient after the end of slip had good correlation with groan noise.
