Abstract: Direct-connected range extender torque ripple of the engine is transmitted to the shaft of the coaxial generator. When the excitation frequency is coupled with the structural mode, the shaft resonance will be excited, obvious abnormal noise is heard. To address this issue, a combined finite element model of the rotor shaft and crankshaft is established using the finite element analysis method. Simulation calculate the modal and vibration mode of the shafting, and lock the problem mode in combination with the modal test; The modal contribution analysis identified a significant contribution from the rotor side. It proposes optimizing parameters such as the spoke angle, spoke thickness, and span of the rotor support bracket to achieve the optimal structure. Compared to the U-shaped structure, the T-shaped structure reduces modal strain energy by up to 50% and decreases the maximum vibration from impact by over 87% in vehicle testing. Subjective ratings improve by 1.5 points. It effectively solves the torsional vibration problem of the shafting caused by the direct connection structure of the range extender, which provides a reference for the design of the shafting structure of the direct connection range extender.

Key words: torsional vibration; range-extended generator; rotor bracket; strain energy; modal contribution

摘要： 直连式增程器发动机转矩脉动会传递到发电机转轴，当激励频率与结构模态耦合时， 会激起轴系共振，产生明显的异响。为了解决该问题，借助有限元分析方法，建立转子轴和 曲轴联合有限元模型。仿真计算轴系的模态及振型，结合模态测试，锁定问题模态；模态贡 献量识别到转子侧贡献较大。提出优化转子支架的辐条角度、辐条厚度和跨距等参数，得到 最优结构。相比 U 型结构，T 型结构模态应变最大能降低 50%，实车验证敲击振动最大降低 超 87%。主观评分提升 1.5 分，有效解决增程器直连结构产生的轴系扭振问题。这可为直连 增程器轴系结构设计提供参考。

关键词: 扭振；增程发电机；转子支架；应变能；模态贡献量