- The cold / hot forging drawing is determined by the helical gear part drawing.
- The influence of the tooth shape and size of cold precision forging preform on the cold precision forging process of helical gear is studied. Two tooth profile schemes of cold precision forging preform with uniform diffusion tooth profile and non-uniform diffusion tooth profile are designed respectively; The finite element analysis of each scheme is carried out by DEFORM-3D software. The numerical simulation results show that when the uniform diffusion tooth profile scheme is adopted, the forming load stress distribution of the gear blank with the cold precision forging amount of helical gear tooth profile of 0.2mm is relatively good, but the cold precision forging amount is too small to meet the expected requirements of improving the surface forming quality and dimensional accuracy of helical gear. When the non-uniform diffusion tooth profile scheme is adopted, the forming load of helical gear blank with the maximum cold precision forging amount of tooth profile of 0.6mm is more reasonable, the material flow is more intense, and the forming quality of tooth profile surface is good, which meets the expected goal of cold precision forging step; Thus, the optimized tooth shape and size of cold precision forging preform are determined.
- The influence of the tooth shape and taper of the preform of closed hot die forging on the closed hot die forging process of helical gear is studied. Based on the diversion theory, an approximate trapezoidal tooth profile scheme is proposed. The numerical simulation shows that when the tooth height of the helical gear blank is 5.8mm, the forming load and stress-strain distribution of the workpiece are the most ideal. However, by observing the metal flow direction in the forming process of the helical gear blank, it is found that the tooth profile of the helical gear blank is not formed at the same time, and the large end tooth profile on the outer diameter side of the helical gear blank begins to form before the small end tooth profile on the inner diameter side, This will affect the forming quality of helical gear; Using the concept of equivalent blank, reduce the bevel angle of the gear blank root and let the small end of the tooth shape begin to form first. Through simulation, it is found that when the taper of the helical gear blank is 3 ° smaller than the bevel angle of the tooth die root, the tooth shape of the helical gear blank can be filled with the cavity at the same time. Thus, the optimized tooth shape and taper of the preform of closed hot die forging are determined.