Fully referring to the idea of shunting method, it is decided to adopt the approximate trapezoidal tooth profile scheme with the size between 1 / 2 tooth height and full tooth height, so as to leave a certain shunting space between the gear blank and the hot forging die, so as to improve the material flow performance of spur gear blank, as shown in the figure.
In order to further study the influence of the tooth profile height of spur gear blank on the closed hot die forging process when the approximate trapezoidal tooth profile scheme is adopted, the design scheme is as follows:
| Scheme I | Scheme II | Scheme III | Scheme IV | Scheme V | |
| Tooth profile height d / mm | 4.9 | 5.2 | 5.5 | 5.8 | 6.1 |