Measurement and assessment of noise caused （测量和评估引起的噪声）.pdf

Measurement and assessment of noise caused by vehicle brake systems a b Günter Mauer and Michael Haverkamp a HEAD acoustics GmbH 52134 Herzogenrath-Kohlscheid b Ford-Werke GmbH Köln 50725 Köln Germany ABSTRACT During the last years the overall sound level inside of modern vehicles continuously de- scended. In consequence an increasing variety of low level noises is not masked any longer. A specific noise, however, can lead to annoyance of the driver, even if its level is low. Thus customers frequently claim about sound quality problems. While the customers’ request on performance and durability of brake systems increases, naturally causing increased noise propensity, the sensitivity towards brake noise increases in-parallel. As a result of rising customers’ claims and expectations, car manufacturers and brake sys- tem suppliers started to extend the scope of their performance and durability tests for acoustical examinations. Up to now these examinations focus on the perception of brake noises inside the car. But since brake noise can attract the attention of potential customers, also the reduction of exterior noise emissions is of rising importance. Additionally, among the various vehicle sounds brake noise plays an important role for the overall acoustical env