On the Interaction of a Two-Pin-Disc System with Reference to the Generation of Disc-Brake Squeal 780331
Previous investigations using a single-pin-disc system have suggested that the mechanism of disc brake squeal is explainable in terms of a geometrically induced or kinematic constraint instability. The experimental results and theoretical analysis to be presented further endorse this idea while demonstrating that interactive coupling effects using a two-pin system can produce both enlarged and reduced regions of noise generation.
Two steel pins independently supported on flexible cantilevers are pressed into contact with a steel disc which rotates at a constant speed. Assuming the system to be undamped and having linear characteristics, the pin sub-systems are each modelled to have three degrees-of-freedom and the disc to have a single degree-of-freedom. The unstable regions are shown to depend primarily on the orientations of the pins to the disc surface. For similar orientation angles the unstable regions are comparable with those produced for a single pin while for dissimilar angles there are configurations of the system which develop reduced regions of instability.
Experimental recordings of squeal noise generation are in general agreement with the theoretical prediction, which leads to the conclusion that the occurrence of disc-brake squeal noise may be reduced by arranging the pads to react in a dissimilar manner on the disc.