"S" cam brake noise at low speed

Abstract

Noise and vibration characteristics of an "S" cam brake system is investigated. Experimental works include the modal testing of individual brake components, the impact test with the assembled brake system and the dynamic test during braking operation in the laboratory. It is found in the modal testing that the vibration modes of individual brake components are not directly related to the destructive noise and vibration characteristics detected in the field operation. It is suspected that two analytically and experimentally identified vibration modes of the assembled shoe may cause the destructive noise and vibration of the brake system. It is observed in the dynamic test that the secondary (primary) shoe of right (left)-hand brake assembly becomes unstable when the drum is driven backward and that the instability is mainly due to the cam geometry, the rotation direction and probably the lining property. An attempt is made to make the system stable by installing a damping device on the unstable shoe.