Abstract:
To address the occurrence of brake noise during the parking brake application in subway vehicles equipped with new type of lightweight friction pairs (aluminum-based composite brake discs and synthetic brake pads), field tests and analyses of the brake friction noise were conducted. Furthermore, by establishing a finite element model of the lightweight brake friction pair and conducting complex modal simulation analysis under braking conditions, the study explored the influence of parameters including friction coefficient, elastic modulus, and braking clamping force, and subsequently proposed measures to suppress brake noise. The results indicated that the main frequency of the brake friction noise was high-frequency brake squeal at around 3 000 Hz. The friction coefficient and elastic modulus of the friction pair had a significant impact on the negative modal characteristics of the brake noise, while the braking clamping force had a relatively smaller effect. Based on the simulation results and in accordance with engineering application requirements, the original brake pads were replaced with synthetic brake pads that had a moderate elastic modulus and a relatively low friction coefficient. Subsequent parking brake tests confirmed that there was no brake squeal during vehicle braking. Therefore, by adjusting the elastic modulus of the synthetic brake pads and reducing the friction coefficient, the brake squeal during the braking process could be effectively suppressed in lightweight friction pairs.