冲焊型液力变矩器叶片回弹规律及抑制技术

冲压焊接型液力变矩器由于便于量产而被广泛应用于汽车，其是自动变速箱的核心部件. 液力变矩器性能直接由叶片形状决定，由于叶片在冲压过程中存在回弹变形，因此针对叶片冲压回弹规律及其对性能的影响开展研究. 首先利用有限元方法对冲压过程及回弹变形进行仿真，并采用流场数值模拟研究了不同回弹程度对变矩器外特性的影响规律，然后通过在叶片中间流线处开设拉延筋抑制叶片冲压起皱和回弹现象，最后制造叶片样件验证回弹抑制有效性，并通过液力变矩器样机试验验证流场数值模型计算精度. 研究结果表明涡轮出口回弹对变矩器性能影响显著，最高效率和起动泵轮能容分别增大了0.067%、8.18%，起动变矩比减小了1.41%. 样机实验验证表明冲压回弹仿真模型与计算流体动力学模型准确度高，其计算结果与实际结果吻合度较好，拉延筋结构可以较好的抑制叶片最大回弹偏差并改善回弹分布. 

Springback Characteristics of Stamped Torque Converter Blades and Its Suppression Technique

Stamping welded hydrodynamic torque converter, the core part of automatic transmission, is widely used in automobiles because of easy to mass-produce. Its performance is directly determined by the shape of the blade. Because the blade occurs springback deformation in the stamping process, this article focuses on the blade stamping springback rule and its effect on performance. First, the stamping process and springback deviation were simulated by finite element method and the influence of different springback deviations on torque converter external characteristic was studied by numerical simulation of flow field. Then the blade wrinkling and springback were inhibited by setting draw-beads in the middle streamline of the blade. Finally, the blade sample was manufactured to verify the effectiveness of springback suppression, and the calculation accuracy of flow field numerical model was verified by the hydraulic torque converter prototype test.. The results show that, the turbine outlet springback has a significant effect on the performance of torque converter. The maximum efficiency and the stall pump capacity increase by 0.067% and 8.18% respectively, and stall torque ratio decreases by 1.41%. The prototype experiment shows that the accuracy of simulation model and the computational fluid dynamics model is higher, and the calculated results have high coincidence degree with the actual results. The draw-bead can better inhibit the maximum springback deviation of blades and improve the springback distribution.