基于奥氏体不锈钢磁钢护套对电机电磁性能影响的分析

Analysis of Influence of Austenitic Stainless Steel Magnetic Steel Sheath on Electromagnetic Properties of Motor

磁钢护套不仅对高频磁场起到屏蔽作用,而且对磁钢具有加固、保护和良好的散热功效,同时有助于电机装配工艺流程。由于非导磁性的磁钢护套不影响电机的电气隙尺寸和输出特性,因此无磁性的奥氏体不锈钢被广泛的应用于磁钢护套中。但不锈钢原材料在冶炼或锻压过程中材料成分的偏稀或热处理不当,使奥氏体中会出现少量铁素体或马氏体组织,导致磁钢护套呈现弱磁性,从而影响电机的电磁输出特性。本文分别以一台分装式有刷直流力矩电机和一台组装式无刷直流力矩电机为例,基于Flux建立有刷直流力矩电机和Ansys建立无刷直流力矩电机的二维有限元仿真物理模型求解域,分析奥氏体不锈钢磁钢护套对力矩电机的电磁性能影响,最后通过研制工程样机,进行仿真数据与实测数据对比分析,明确了应用奥氏体不锈钢磁钢护套电机的精确设计裕量,为电机方案研制初期阶段提供了一定的工程设计意义和理论依据。

Magnetic steel sheath not only plays a shielding role in high-frequency magnetic field,but also has a strengthening,protection and good heat dissipation effect on magnetic steel,and helps the motor assembly process.Since the non-magnetic magnetic steel sheath does not affect the electrical gap and output characteristics of the motor,non-magnetic austenitic stainless steel is widely used in the magnetic steel sheath.However,the thin material composition or improper heat treatment of stainless steel raw materials in the process of smelting or forging,so that a small amount of ferrite or martensitic organization will appear in austenite,resulting in weak magnetism of the magnetic steel sheath,thus affecting the electromagnetic output characteristics of the motor.In this paper,a distributed brushless DC torque motor and a packaged brushless DC torque motor were respectively taken as examples.The solution domain of the two-dimensional finite element simulation physical model of the brushless DC torque motor was established based on Flux and Ansys,and the influence of austenitic stainless steel magnetic steel sheath on the electromagnetic properties of the torque motor was analyzed.Finally,an engineering prototype was developed.By comparing the simulation data with the measured data,the precise design margin of austenitic magnetic steel sheathed torque motor was defined,which provided a certain engineering design significance and theoretical basis for the initial stage of the motor project development.