永磁同步电机转子冲片疲劳仿真分析方法研究

余春祥，彭国民，郭丰

无锡星驱动力科技有限公司，江苏 无锡  214000

摘要：为解决某电驱总成转子冲片的疲劳断裂故障，建立冲片有限元模型，对冲片疲劳断裂现象进行模拟，分析冲片厚度、冲片材料各向异性、胶料、电磁力、磁钢与冲片接触不均匀性、温度等因素对冲片应力的影响；基于应力试验结果修正材料应力S-寿命N曲线；优化转子冲片结构，增大中间隔磁桥厚度和断裂处圆角半径，并对优化后冲片进行仿真与耐久试验验证。结果表明：冲片应力随着冲片厚度增大而下降，随磁钢与冲片接触不均匀性增大而显著增大；材料各向异性、胶料、电磁力对冲片应力的影响较小，而温度对冲片应力的影响较大；修正材料S-N曲线后，疲劳寿命的仿真结果与试验结果高度吻合，验证了模型的准确性；优化方案的仿真疲劳寿命为218万次循环，远高于3万次的要求，且通过了耐久试验验证。该方法成功解决了冲片断裂问题并提高了冲片疲劳寿命预测的精度。

关键词：电驱总成；永磁同步电机；冲片；应力分析；疲劳分析

Fatigue simulation method study on rotor punchings of a permanent magnet synchronous motor

YU Chunxiang, PENG Guomin, GUO Feng

Wuxi InfiMotion Propulsion Tcchnology Co., Ltd., Wuxi 214000, China

Abstract: In order to solve the fatigue fracture fault in the rotor punchings of an electric drive unit(EDU) assembly, a finite element model of the punchings is established to simulate the fatigue fracture phenomenon of the rotor punchings. The influence of punching thickness, punching material anisotropy, adhesive material, electromagnetic force, uneven contact between magnetic steels and punchings, temperature and other factors on punching stress are analyzed. The S-N curve of the material is refined based on stress test results. The rotor punching structure is optimized, the thickness of the intermediate magnetic bridge and the fillet radius at the fracture point are increased, and simulation and durability testing are conducted to verify the optimization scheme. The results show that the punching stress decreases continuously with the increase of punching thickness, and significantly increases with the increase of uneven contact between the magnetic steels and punchings. The influence of material anisotropy, adhesive, and electromagnetic force on the stress of the polarizer are relatively small, while temperature has a greater impact on the punching stress. After correcting the S-N curve of the material, the fatigue life simulation results are highly consistent with the experimental results, verifying the accuracy of the model. The simulated fatigue life of the optimized solution is 2.18 million cycles, far exceeding the requirement of 30 000 cycles, and has been verified by durability tests. This method successfully solve the problem of punchings fracture and improved the accuracy of punching fatigue life prediction.

Keywords: EDU assembly; permanent magnet synchronous motor; punching; stress analysis; fatigue analysis