Precise Simulation and Test Closed-Loop Verification of Drag Torque for Brake Caliper of In-Wheel Electric Motor

Aiming at the industrial pain points of high control difficulty of drag torque, low precision of traditional simulation and lack of authoritative test closed-loop verification for the special brake caliper of in-wheel electric motor, taking the YF3501S73 front brake caliper and YF3502S73 rear brake caliper as the research objects, a high-precision finite element simulation method coupling the nonlinearity of piston seal material with bilateral parallel return springs was proposed, and the simulation boundary conditions were calibrated by finely matching the bench test working conditions. To ensure the authority and engineering practicability of the research results, the drag torque bench test was carried out in strict accordance with QC/T 592-2013 Performance Requirements and Bench Test Methods for Hydraulic Brake Caliper Assemblies, and in alignment with the international brake drag test specifications of SAE J2923 and JASO C448, thus realizing a complete closed loop of simulation modeling and test verification. The research results show that the error between the calibrated simulation model and the experimental measured results is only 1.37%, which is much lower than the 8.57% error of the traditional simulation; the measured maximum drag torque of the front brake caliper at the 10th circle is 1.30 N·m, and that of the rear brake caliper is 0.66 N·m, which is far better than the industry standard limit (≤3.5 N·m). This study solves the technical bottleneck that the simulation of brake caliper drag torque is divorced from the actual working conditions, takes into account the characteristics of micro components and the adaptability of vehicle integration working conditions, and provides a replicable simulation-test joint verification idea for the research and development of supporting brake components for in-wheel electric motors of new energy vehicles, which has strong engineering promotion value. Keywords: Brake Caliper; In-Wheel Electric Motor; Drag Torque; Finite Element Simulation; Third-Party Bench Test; Parallel Return Spring