To meet the vibration isolation requirements, the twins torsion spring is placed between the pivot and the clutch, which can make the generator and front gear train run more stably, and improve the durability of the system. In this study, the twins torsion spring was winded by SUS 631 stainless steel, and was treated by medium-temperature tempering. The fatigue life of the twins torsion spring was investigated. The morphology of fatigue fracture of the twins torsion spring was examined by scanning electron microscopy (SEM). And the vickers micro-hardness of the spring was tested by micro-hardness tester. Large amount of shrinkage porosity can be found in the fatigue extension area and instantaneous fault zone. And the average micro-hardness was about 565.5 HV on the area near the fracture. In order to analyze the causes of the fracture, the fatigue life was simulated by finite element (FE) numerical analysis. The simulation results are consistent with the experimental test of fatigue.

为了满足隔振要求，将双扭簧置于枢轴与离合器之间，可以使发电机和前齿轮系更稳定地运行，并提高系统的耐用性。在这项研究中，双扭扭簧由SUS 631不锈钢缠绕，并经过中温回火处理。研究了双扭扭簧的疲劳寿命。通过扫描电子显微镜（SEM）检查了双扭扭簧的疲劳断裂形态。并用显微硬度计对弹簧的维氏显微硬度进行了测试。在疲劳扩展区域和瞬时断裂带中会发现大量的收缩孔隙。断裂附近区域的平均显微硬度约为565.5 HV。为了分析破裂的原因，通过有限元数值分析来模拟疲劳寿命。仿真结果与疲劳试验结果吻合。