Piston and Guide-Pin Rattle Noise Mitigation in Electro-Mechanical Brake Caliper

Brake caliper commonly utilizes rubber or spring components to maintain specific clearance range for sliding characteristics, rendering them susceptible to rattle noise. The Electro-Mechanical Brake (EMB) caliper has attracted attention for its advantageous features such as reduced brake drag, optimized vehicle layout, and precise brake control. However, the inclusion of additional components related to the dry-type pressurizing system results in increased caliper weight and susceptibility to rattle noise. This study thoroughly examines rattle noise characteristics in our prototype EMB caliper, identifying primary noise sources on the piston and guide-pin sides. Implementing piston seals and guide-pin boots tightening force proves the effectiveness in improving rattle noise characteristics. Collisions between the piston and ball-screw head can be mitigated by piston inner seal, significantly reducing rattle noise. The effectiveness of the piston outer seal is limited and can be sufficiently substituted through improved tightening force in the piston boot. Additionally, the guide-pin side is identified as significant source of rattle noise, with enhancements in guide-pin boot tightening force showing improved rattle noise characteristics, particularly under new pad conditions. These findings provide valuable insights for developing EMB calipers to minimize rattle noise, contributing to quieter and more efficient future braking systems.