Abstract
Brake squeal is a serious problem of automobile brake noise. It is uncomfortable sound appearing sometimes when driver uses brakes. The brake squeal is too complex phenomenon to find out effective solution for preventing the noise. It has been said long time that one of dominant factor causing brake squeal is velocity dependence of friction coefficient between pad and disk, so called "dμ/dV". There is one of theories that a system become unstable dynamically when dμ/dV<0 and then brake squeal occurs. Many researchers reported about measurement results of dμ/dV, obtained by calculating friction coefficient gradient for sliding velocity. Although the sliding velocity is generally measured at steady sliding condition, it is seemed to be including minute vibration when brake squeal is occurring. In this paper, dμ/dV value was calculated by measured friction coefficient and sliding velocity between pad and disk including minute vibration at brake squeal frequency. The results indicated difference of dμ/dV between steady sliding condition and minute vibrating condition. Additionally, tendency of dμ/dV gradient variation differs by each brake pad.
