Design And Brake Performance Study Of Brake System Actuator For Commercial Bus

As one of the important systems of the vehicle,the brake system ensures the safety of it,and the actuator plays an important role as the component of the braking system.At present,the air disc brake used in the commercial bus has some problems,such as large volume,low braking efficiency and environmental hazards.This paper,considering auxiliary brake and main brake function,designs the auxiliary brake actuator-double stators eddy current brake and the main brake actuator-Electromechanical Brake?EMB?,and the braking performance is studied.The specific research contents are as follows:The background and significance of the research are expounded,and the research status of the eddy current brake and EMB actuator at home and abroad is analyzed.Combined with the commercial bus,considering auxiliary brake and main brake function,the general scheme of brake actuators is put forward.The auxiliary brake actuator is identified as double stators eddy current brake,and the main brake actuator is identified as EMB actuator.According to the scheme,the equation of braking torque of the actuator is derived.According to the performance evaluation index of the eddy current brake and the requirements of the brake design,the parameters design of auxiliary brake actuator is completed,including the magnetic circuit design,the brake disc parameters,the iron core parameters,and the air gap thickness.Then the 3D simulation model of the brake is established according to the determined parameters,and the influence of different magnetic circuits on braking torque is analyzed to optimize the magnetic circuit.On the basis of magnetic circuit optimization,the influence of electromagnetic parameters on braking torque of auxiliary brake actuator is analyzed.Based on Maxwell equations,the electromagnetic field equations and eddy current mathematical model suitable for finite element analysis are derived.The brake 3D model is introduced into the Maxwell,and the electromagnetic field and the distribution of the eddy current field are simulated and analyzed.Then the influence of the electromagnetic parameters on brake torque characteristics is analyzed,and some parameters of the eddy current brake are optimized.Main brake actuator-EMB actuator motor is designed.A 50W EMB permanent magnet brushless DC motor is designed based on the brake parameters of the air disc brake with the torque of 10.3N·m and the no-load speed of 370.rmin^-1.The performance of the motor in the clearance elimination and clamping force increasing stages is simulated and analyzed.Compared with the clamping force data of the mechanical brake test platform,the rationality of EMB actuator replacing air disc brake is verified.