Abstract
Keywords:
Brake Squeal Noise, Laser Vibrometer
Abstract
Brake Squeal Noise, which is a noise phenomenon occurring from 20 ~ 20kHz, is becoming a must do issue in our days, rather than an important issue, which it used to be. Various approach such as the modal analysis using accelerometers, FEM analysis etc… was made to solve this kind of problem, but no technology other than the Laser Vibrometer was successful enough to deal with noise problem in moving parts. The Laser Vibrometer was used to identify the modal problem factors when the brake was squealing, and modal coupling of the pad/rotor as a result of geometrical alignment was found to be the key to produce the squeal noise problem. This pad induced noise, which is the most common type of squeal was studied by many, and several prescription was found to solve the problem ; changing the chamfers, shortening the pad length, rotor asymmetry, stiffening the rotor, rotor damping, using linings with a lower coefficient etc. Out of these, G company choosed to solve this problem by changing the noise shim and applying a 5mm deeper chamfer on the pad. As a result, noise problem almost disappeared, only leaving a minor problem when the pad was tested with an asymmetric bracket. This new approach to solve the noise squeal problem using the Laser Vibrometer was successful, and further rotor noise research on other vehicles and techniques will be studied in the near future.