China’s gear manufacturing industry started in the 1950s. After more than ten years of development, it has initially laid the development foundation by the 1960s, and gradually formed a complete range of gear manufacturing industry system. In the following decades, with the introduction of a large number of complete sets of equipment and the influence of national policies, China has trained a number of specialized technical teams in the gear industry, with considerable technical force in design optimization and manufacturing process. The gear technology has been further improved and the gap with the advanced level of foreign countries has been gradually narrowed.
Zheng Jianshe successfully applied the precision die forging near net shape technology of spiral bevel gear to complete the precision die forging of spiral bevel gear of Fiat front axle. Using this technology, the gear bearing capacity and gear strength can be increased by 1.5 ~ 1.8 times, the material utilization rate can be more than 80%, the production efficiency can be increased by 3 ~ 5 times, the power energy can be saved by more than 200%, the service life of the gear is improved, and the economic and social benefits are significantly improved.
Zhang Meng and others conducted experimental research on the plastic forming process of the driving spiral bevel gear of the automobile differential, designed and processed the test die, carried out the plastic forming experiment relying on the universal tensile testing machine, studied the metal flow on the section and the filling process of the tooth profile in the gear forming process by using the method of grid experimental analysis, and revealed the trend and distribution of the internal metal fiber, The stroke pressure curve of lead specimen of plastic forming spiral bevel gear is obtained, which provides a reliable experimental basis for the structural design of forming die and the calculation of force and energy parameters.
On the basis of split forging, Zhang Qingping of Shandong University and others studied the tooth profile design method of die for cold precision forging process of two-step formed spur gear. The tooth profiles of final forging die and pre forging die were designed by modified modulus method and displacement method respectively, and optimized by orthogonal test and numerical simulation. The simulation results show that the new process improves the filling performance of metal.
Tian Fuxiang and others put forward the new process of “one fire and two forging” and the new die structure of closed precision forging of spiral bevel gear. This structure ensures the accurate positioning of the blank. Using the floating die and die core structure, the rough forging of gear without flash is realized. The concept of equivalent linear expansion rate and the linear expansion theorem of involute tooth profile are put forward. The main influencing factors are analyzed and the design formula is given. The test of the new process shows that with this structure, The material consumption and production cost are reduced, and the die life and production efficiency are improved.
Wang Huajun and others carried out three-dimensional rigid plastic finite element simulation and lead sample physical simulation on the precision forging process of driven spiral bevel gear, showed the forming process of tooth profile and the change trend of internal metal, and obtained the metal flow law, deformation force parameter characteristics, strain distribution state and tooth profile filling mode in the precision forging process of spiral bevel gear.
Kou Shuqing and others carried out finite element numerical simulation analysis and Research on the two-step forming process of car bevel gear with closed die forging as pre forging and closed die forging, hole shunting and constraint hole shunting as final forging respectively. The metal flow law and mechanical field distribution in the forming process were obtained. Shunting measures were taken to divert the constraint hole in the final forging stage, which reduced the forming load and improved the corner filling capacity. The research results show that the numerical analysis is accurate, The process design is reasonable.
Jiang Hongzhi and others carried out finite element numerical simulation analysis on the precision forging process of hollow spur gear, and obtained the metal flow law and deformation mechanical characteristics in the deformation process.