Abstract: To address the problem of resistance increase caused by the bending process of copper wires for hairpin motors, this paper proposes a resistance prediction model that comprehensively considers geometric deformation and microstructural evolution. Through theoretical derivation and experimental verification, the model quantifies the influence mechanism of bending angle and bending times on wire resistance, and reveals the contribution of plastic deformation-induced grain boundary proliferation and dislocation density increase to electrical resistivity. Experiments show that the resistance value increases significantly with the increase of bending times. The correction coefficient k=5.25×10-5 in the model, obtained by fitting experimental data, integrates the actual operating condition variable of bending times into the resistance calculation model. This model makes up for the limitation that traditional resistance formulas only rely on geometric dimensions and material resistivity, achieves accurate matching between the theoretical model and measured results, provides a quantitative tool for predicting resistance changes under complex deformation, and offers theoretical support for the process optimization of high-precision copper wires for hairpin motors.

Key words: hairpin motor; pure copper; copper wire; bending; process optimization; resistance performance

摘要： 针对扁线电机铜导线折弯工艺导致的电阻升高问题，文章提出了一种综合考虑几何形 变与微观结构演变的电阻预测模型。通过理论推导与实验验证，量化了弯折角度、次数对导 线电阻的影响机制，并揭示了塑性变形诱导的晶界增殖、位错密度升高对电阻率的贡献。实 验表明，电阻值随折弯次数增加呈显著上升趋势，模型中由实验数据拟合得到的修正系数 k=5.25×10-5，将折弯次数这一实际工况变量融入电阻计算模型，弥补了传统电阻公式仅基于 几何尺寸与材料电阻率的局限性，实现了理论模型与实测结果的精准对接，为预测复杂变形 下的电阻变化提供了量化工具，也为高精度扁线电机导线的工艺优化提供理论支持。

关键词: 扁线电机；纯铜；铜导线；折弯；工艺优化；电阻性能