Abstract
This study discusses the benefit of holes opened on frictional surface of brake disc for preventing the stick-slip and squeal at braking. At first, the change of stability of the brake pad passing on hole was analyzed by 2-D simplified brake system model. To reveal the influence of configuration of the hole, three types of discs were prepared whose size of holes was different. Effect of the holes diameter on the squeal behavior was investigated by the bench test. The sound pressure levels and the frequencies of three types of discs were measured when the brake squeal was happened at low speed condition. Observed fluctuation in the brake torque was analyzed with FFT to estimate exciting force at squeal. To investigate the behavior of the pad when the pad passed through hole, strain variation near the contact area of the pad was measured. This study found that, the stable region was extended when large hole was opened on the disc, whereas the pad was unstable on the entirely flat surface of the original model without hole. The sound pressure level of the brake squeal at significant peak of SPL around 700Hz was reduced when the diameter of holes was increased. The peak of brake torque amplitude in low frequency was decreased, when the large hole was opened on the disc. Brake squeal was reduced on the hole opened disc by that intensive contact of the pad was promoted near the trailing edge by passing over the hole. Keywords: brake disc, brake squeal, motorcycle, stick slip, pad, strain