Stick-slip motion of disc brake pads

In order to examine the brake noise occurring at very low speeds, disc brake pads were connected with coil springs, and the stick-slip motion at a low friction speed was measured. The stick-slip motion was relatively prompted with steel fibers contained in the pad material. The addition of graphite to the pads and the lubrication of the frictional surface with water or castor oil increased the amplitude of the stick-slip motion. On the other hand, the formation of the transferred films on the opposite surfaces and the addition of cashew nut resin to the pads decreased the amplitude of the stick-slip motion. These results were explained by using the friction model of the disc brake pad. Moreover, the amplitude of the stick-slip motion and the brake noise level were compared.