Analysis of the Effect of the Wedged Type Brake Caliper Piston on Brake Drag

Recently, there’s a massive flow of change in the automotive industry with the coming era of electric vehicles and self-driving (autonomous) vehicles. The automotive braking system field is not an exception for the change and there are not only lots of new systems being developed but also demands for researches for optimizations of conventional brake systems fitting to the newly appeared systems such as E-Booster and Electric Motor Brake (EMB) Caliper. Taking the Electric Motor Brake Caliper for example, it is considered as a very important and useful system for autonomous vehicles because the motor actuator of the caliper is much easier to control with ECUs compared to the conventional hydraulic pressure system. However, easy of control is not the only thing that excites brake system engineers. Since the whole actuating mechanism of the brake systems has been changed, engineers now can see some new ways to solve chronic problems in conventional brake systems such as brake residual drag, brake fade and so forth. Brake residual drag can be possibly solved by simply connecting the motor actuator of the caliper to the brake piston so that ECUs can actually control the whole life cycle of brake torque creation and extinction. However, there have to be a few more components needed on top of the fact that its structure inside the brake piston could be much more complex than it used to be and this could cause some side effects as well. With the reasons above, this study illuminates the concept for a way of reducing brake residual drag in the new systems by enhancing the capability of piston roll-back of the caliper without any complex structures. Several test results and CAE analysis are presented and discussed to get a better understanding of the concept.