Optimal Design of EPB Caliper Using DOE 2017-01-2519
An Electrical Parking Brake (EPB) system is a device that operates to park the vehicle automatically with the push of a button instead of using conventional hand or foot levers which in some ways makes it the first by wire type of brake system. As such, it is being considered in some vehicle architectures as an automatic redundant backup for vacuum-less brake systems or autonomous cars.
The EPB system is generally divided into cable puller and motor on caliper (MOC) types. Recently, the MOC type EPB is being more widely applied in the global market due to product competitiveness and cost effectiveness. The MOC type EPB is composed of the caliper body, torque member, pad assembly, nut assembly and actuator. Among them, the caliper body and torque member play a main role in the robustness of the EPB system and occupy more than 80% of the total weight. Therefore, optimal design of the caliper body and torque member to maximize stiffness while minimizing weight is systematically important in the design of an EPB system.
In this paper, stiffness and weight optimization was carried out for an EPB caliper body and torque member starting out from basic shapes. The objective functions for the EPB caliper body and torque member were designated as its weight and stiffness. Also EPB specific characteristics such actuator weight, and mounting requirements were considered. Main dimensions considered critical from the existing design were taken as design variables. Design of experiments (DOE) procedure was used to set the levels of design variables and the effectiveness of each level was checked using CAE. Through discrete results, we were able to find continuous approximation models in a specified range. Based on the regressive model, design variables that could minimize weight under constant stiffness conditions were adopted. From this, it was possible to obtain an optimal design of an EPB caliper body and torque member.