Analysis for Reducing Low Frequency Squeal of Disc Brake

The phenomenon of low frequency squeal of disc brake occurs only under special conditions and the occurrence rate is very small compared to high frequency squeal. Therefore it is very difficult to simulate and reproduce the squeal by bench test. There was no method established for evaluating and reducing the low frequency squeal before this paper. The detail methodology of the experimental analysis and Finite Element Modeling utilized to solve this problem in a short time frame is discussed in this paper. First, the squeal occurred on the vehicle must be simulated and reproduced on a laboratory bench by all means as an evaluation tool, so that the countermeasure for the squeal can be evaluated by the tool. In this example, a new bench test was successfully implemented from the vehicle conditions that generated the squeal. Second, the vibration mode of the squeal was estimated by an experimental oscillation test with disc brake assembly to identify key components for FEM analysis. The vibration mode of the carrier being fixed to the steering knuckle was analyzed with FEM. Through multiple geometry modifications of the carrier with knuckle FE model, one revised geometry was found to be effective to reduce the squeal phenomenon. Finally, the carrier with revised geometry model was then tested by the laboratory bench test with successful reduction of the low frequency disc brake squeal. In conclusion, the combined use of laboratory bench testing and FEM modeling significantly reduce the solution time for low frequency squeal of disc brake.