For a long time, researchers and scholars all over the world have made unremitting efforts on the deformation law analysis, die design and process, quality and precision control of gear precision forging through theoretical derivation and experimental research, and achieved fruitful and gratifying results.
Dohamann f applied the numerical approximation method and principal stress method to analyze the stress and flow in each stage of gear cold forging. Chitkara N R, from the College of science and technology, Manchester University, UK, used the upper bound method to analyze the forging process of spur gear. Then, the numerical simulation analysis was made on the stress-strain law of the incremental forging process of spur gear. 1992 knoerr M et al. Simulated various forging processes such as aluminum alloy forging and bevel gear forging by using the two-dimensional finite element simulation software deform, analyzed the stress of the forming die, successfully predicted the possible forming defects according to the simulation results, and optimized the process parameters. In 1996, Choi J C and Choi y used the upper bound method to analyze the forging process of spur gear, obtained the dynamic admissible velocity field of the forming process, analyzed and calculated the influence of gear tooth number, modulus, radial displacement coefficient, friction and other factors on the forging process of gear, and obtained a conclusion consistent with the experimental results.
In China, in 1990, Huang Liangju and others used the grid method to analyze the metal flow law during the closed precision forging of cylindrical gear blank, and theoretically analyzed the forming force in each deformation stage. Li Hongbo of Yanshan University used the upper bound method to analyze the precision forging process of spur gear, and obtained the deformation force in the forming process and the change law of boundary shape when the blank is filled in the die bore. In 1997, Jiang Hongzhi and Lin Zhiping of Nanchang University analyzed the precision forging process of spur cylindrical gear by using the upper bound method, and numerically simulated its forming process. The optimal blank overall dimension and load stroke curve of precision forging process were obtained. This result is consistent with the subsequent experimental results. Zhang Qingping of Shandong University put forward the method of combining closed die forging and shunting method to form spur gear, and carried out numerical simulation by using finite element simulation software to obtain the optimal forming scheme. Based on the principle of floating die, Tan Xianfeng and others used the three-dimensional forming simulation software DEFORM-3D to optimize the skinning position in the precision forging process of spur gear.