Brake squeal of the light vehicle disc brakes have been the subject of numerous studies in the last thirty years. Several analytical and numerical models as well as dynamometer and vehicle test procedures are widely used in the industry. The noise performance of many vehicles have been improved significantly over the last few years. On the other hand, the squeal noise of the heavy-duty vehicle drum brake has not been studied extensively. The noise performance of the heavy-duty drum brake has been lagging behind that of the light vehicle brakes. With the implementation of the revised FMVSS121 stopping distance requirement, higher friction materials are needed, which generally results in even more brake noises due to higher excitation. Public awareness of noise influence on the environment is forcing the heavy-duty vehicle brake industry to deliver better brake noise performance.
In this paper, an integrated approach for reducing heavy-duty vehicle drum brake squeal is presented and applied to an actual vehicle. The approach is based on the work on light vehicle brakes, which includes finite element simulation, dynamometer testing and vehicle testing. Differences in modeling and testing between light and heavy-duty vehicle brakes are discussed. Details of finite element modeling and test procedure development are presented. Possible counter measures for the heavy-duty vehicle drum brake squeal are investigated. An innovative friction block shape is presented as an effective solution for the squeal noise observed from the vehicle.