Due to the complex metal flow in the cold extrusion of sun gear, the teeth accuracy of formed sun gear is poor. In order to improve the accuracy of extruded sun gear, a precision sizing method was proposed in this study. Finite element simulation for predicting tooth deviations of finished sun gear was performed using DEFORM, and the influences of key process parameters such as the sizing amount of external gear, interference value of internal spline, die bearing length, and friction factor on gear deviations were examined. The simulation results reveal that the accuracy of extruded sun gear can be significantly improved with the sizing amount of external gear as 0.2 mm, spline interference value as 0.10 mm, die bearing length as 19 mm, and friction factor as 0.12. Finally, experimental investigation was carried out by the developed precision shaping method. The experimental results show that the profile accuracy of external gear after cold shaping operation is the seventh, the gear lead accuracy is the eighth, and the total M value deviation of internal spline is reduced to 0.07 mm, which proves the feasibility of precision sizing method and the correctness of numerical simulation results.

由于太阳轮冷挤压过程中金属流动复杂，成型的太阳轮齿形精度较差。为了提高挤压太阳轮的精度，本研究提出了一种精密定型方法。利用DEFORM对太阳轮成品齿偏进行有限元模拟，考察了外齿轮定径量、内花键过盈量、模具轴承长度、摩擦系数等关键工艺参数对齿轮偏差的影响. 仿真结果表明，外齿轮定径量为0.2 mm，花键干涉值为0.10 mm，模具轴承长度为19 mm，摩擦系数为0.12时，挤压太阳轮的精度可以得到显着提高。最后，实验研究是通过开发的精密成形方法进行的。实验结果表明，冷成形后外齿轮齿廓精度为第七位，齿距精度为第八位，总内花键M值偏差减小到0.07 mm，证明了精密定径法的可行性和数值模拟结果的正确性。