Analysis of Brake Caliper Seal-Groove Design

It is well known that the design of the seal groove assembly in the brake caliper greatly influences the braking performance. The rubber seal performs the dual function of sealing the piston bore and retracting the caliper piston after a brake apply. However, the seal function is affected by the configuration of the seal groove, as well as the friction at the piston/seal and groove/seal interfaces. The material properties of the rubber seal are also important design parameters. Issues such as fluid displacement, piston retraction, piston sliding force, and brake drag are some of the critical brake performance parameters that must be considered in every caliper seal-groove design. Presently, the brake caliper seal groove design is still based on empirical rules established mainly from past experience and its performance is achieved through prototype testing. Indeed, an analytical model that offers some predictive estimate of the seal groove contributions to the braking performance is needed. This will enhance the optimization of the seal groove design, reduce the need for product prototyping and minimize costs. In this paper, we attempt to identify the critical design parameters in the seal/seal groove assembly and quantify their impact on the brake performance parameters.