Research On Influence Factors And Suppression Methods Of Disc Brake Squeal

Brake noise has become a concern for both industry and academia due to its contribution to environmental noise pollution and its impact on the competitiveness of automobiles in the marketplace.This thesis focuses on studying the problem of brake squeal in a floating caliper disc brake of the rear wheel of a passenger car,using a combination of complex eigenvalue analysis and vehicle road tests.First,a three-dimensional model based on the physical structure of the disc brake was constructed,and finite element mode analysis was performed on the main parts.Then,the hammering modal test was used to verify the analytical results and ensure the accuracy of the finite element model.Through finite element complex eigenvalue analysis,the unstable mode of the disc brake system was extracted,and its main frequencies were found to correspond to the squealing frequencies observed during vehicle road tests.The influence of various operating conditions on brake squeal was further analyzed,and it was found that the friction coefficient plays a significant role,while rotational speed and brake pressure have no significant effect.To address the problem of brake squeal,this thesis proposes three different suppression methods: grooving,chamfering,and adding brake shims.Complex eigenvalue analysis was performed on each method and it was found that straight chamfering measures and a single straight groove with a certain width and depth are effective in suppressing brake squeal.The effectiveness of different installation positions,thicknesses,and damping layer thicknesses of the brake shim on brake squeal suppression was also analyzed.Finally,the structure of the brake pad was modified based on a comprehensive evaluation of the above suppression methods.Complex eigenvalue analysis and vehicle road tests were conducted to verify the effectiveness of the modified structure,which was found to significantly suppress brake squeal.