Brake noise analysis on tractive axle of 6x2 tractor vehicle 2019-36-0008

This study aims at analyzing the causes of noise in a heavy vehicle brake system (6x2 tractor) and proposing solutions to improve comfort during braking as it is known that, during the activation of the automotive brakes, noise can be generated in different frequency bands that can cause discomfort to the user and the study of how to reduce it is considerably important to bring more comfort in its use. As a working methodology, firstly, comparative analysis of dimension and material were performed between the axle assembly that presented noise and another axle assembly of a vehicle with no noise adopted as reference. This information was used as the basis for the frequency and acceleration virtual analysis that were validated with vehicle instrumentation and data acquisition. In parallel, vehicle tests with different brake friction materials were conducted. The answers of the dimension and material analysis from the axles assemblies highlighted the specificities of each of them but did not show great influence in the observed noise incidence. The vehicle instrumentation and data acquisition besides validate the virtual data, also showed the system amplitude of vibration which, through comparative tests with the same vehicle with the reference axle and similar vehicles, showed high variation in the acceleration and amplitude of vibration. The vehicle tests with different brake friction material varied the stiffness of the brake system, however, showing no evolution in its integrality but causing the noise at different braking pressure of the presented in those conditions. It is concluded that the difference between the axles assemblies is the assembly of the brake system “S” cam axle which, when actuated, has the rotation contrary to the wheel rotation, which can originate the variations in the acceleration and amplitude of vibration verified in the data acquisition and, therefore, may influence in the noise appearance.