| With the development of new energy vehicles,in-wheel motor driven vehicles have attracted widespread attention due to their high transmission efficiency and high chassis utilization.Due to the limited space of the wheel hub,the design structure of the wheel inwheel motor is compact,especially when operating under high load conditions for a long time,which generates a large amount of heat.Therefore,reducing the heat generated by the wheel in-wheel motor and retaining the original braking system of the car are currently the difficulties in achieving distributed drive of the wheel in-wheel motor.This article focuses on a new type of fan-shaped axial magnetic field in-wheel motor that can retain the original braking system of the car.The motor combines the rotor with the brake disc,and retaining the original braking system of the car will cause new changes in the electromagnetic and loss characteristics of the in-wheel motor,thereby affecting the temperature rise and mechanical characteristics of the motor.This article studies the electromagnetic,temperature rise,and mechanical characteristics of a brake caliper motor by constructing a magnetic thermal mechanical coupling model,and explores the loss suppression methods of this type of motor.The main research content is as follows:(1)Using Maxwell and Solid Works software to jointly construct a finite element model of an axial magnetic field in-wheel motor with a fan-shaped structure containing brake calipers,the effectiveness of the model was verified by constructing a prototype of an axial magnetic field in-wheel motor with a fan-shaped structure containing brake calipers.The no-load and load loss characteristics of the fan-shaped structure axial magnetic field motor with and without brake calipers were compared and analyzed under rated speed conditions,It was found that the torque fluctuation of the axial motor with a fan-shaped structure containing brake calipers under no-load conditions is a negative torque sine wave;Under rated current conditions,the output torque amplitude of motors with brake calipers fluctuates significantly compared to ordinary structure motors;The presence or absence of brake calipers has a significant impact on motor losses,with a relatively small impact on the loss values of traditional components of the motor.The copper loss amplitude of the motor with brake calipers fluctuates greatly,and the eddy current losses of the caliper bracket and back plate account for a relatively high proportion of the overall loss of the motor;When the current is constant,the higher the rotational speed,the higher the proportion of eddy current loss in the motor braking system.(2)Construct a magnetic thermal coupling analysis model to study the temperature rise distribution of a fan-shaped axial magnetic field motor under rated and peak operating conditions.Indicating that the maximum temperature rise component of the motor under both operating conditions is located at the back plate,and the temperature of the lower back plate is higher than that of the upper back plate.Among them,the temperature of the back plate is higher under rated operating conditions;The temperature rise of the core components of the motor under peak operating conditions is higher than that under rated operating conditions;The temperature rise of the motor meets the F-level insulation standard.(3)Construct a magnetic thermal mechanical three field coupled finite element model of the motor,and study the stress and axial deformation of various components of the motor under rated and peak operating conditions.Indicating that the stress and deformation of each component of the motor meet the service conditions;The maximum stress of the motor occurs at the clamp bracket;The axial deformation of the brake pad results in the deformation of the part center away from the rotor,increasing the braking distance.(4)Based on the block suppression eddy current method and material suppression eddy current method,three block methods,radial,circumferential,and axial,were used to simulate and analyze the eddy current losses of permanent magnets.Radial and circumferential block methods can effectively reduce eddy current losses,and the more blocks,the better the loss suppression effect;Axial blocking increases eddy current loss,with more blocks increasing the output torque of the motor;The circumferential block method has the best eddy current suppression ability.Using radial and axial partitioning methods for the backplate,it was found that both partitioning methods can reduce the eddy current loss of the backplate,while axial partitioning of the backplate can reduce the output torque of the motor;Using different materials,analysis was conducted on the back plate and caliper bracket,and it was found that using titanium alloy materials resulted in the best suppression of eddy current losses for the back plate and caliper bracket. |
