A Mechanism of Disc-Brake Squeal

Further results, obtained from a pin-disc system, are presented which support the theory that the generation of squeal noise in disc-brakes is caused by a geometrically induced or kinematic constraint instability. The unstable regions are shown to be dependent on the coefficient of friction between the interacting surfaces and the magnitudes of the physical parameters of the system elements. The relevance of certain system parameters is discussed in relation to a three degree-of-freedom, undamped model having linear characteristics. Some results which appear to contradict the proposed basic squeal generating mechanism are explained. The fugitive nature of squeal noise in disc-brakes is discussed and an explanation is given based on the proposed instability theory.