The material utilization rate and productivity of the machining process are both low, and its blank also has the disadvantages of low strength caused by the cutting of metal streamline. The precision plastic forming process overcomes these disadvantages and has become a main method of gear machining innovation because of its high efficiency and high precision. Precision plastic forming of gears is a new technology with less and no cutting. It is an advanced manufacturing technology of mechanical parts. This technology has been paid more and more attention by researchers at home and abroad. It is one of the key research topics in the field of plastic forming.
In recent years, gear precision forging technology has been paid more and more attention in China. Since the 1990s, China has made rapid development in precision forging gear manufacturing. After more than 20 years of research in China, its application in spur bevel gear has been quite mature, and began to work on the precision forging manufacturing of spiral bevel gear. In terms of comprehensive R & D and application of precision forging technology for gear parts, Jiangsu Pacific precision forging company has established long-term cooperative relations with many universities, gear factories, research institutes and gear professional associations in China. Among them, it has jointly established the “precision forging technology research and development center” with the State Key Laboratory of die technology of Huazhong University of science and technology. At the same time, The company has also established good and stable cooperative relations with nichidai company of Japan and general motors of the United States. Due to the establishment of the system and mechanism of the combination of “production, learning and research”, the enterprise has developed continuously and rapidly. It can be said that the company has first-class technology, equipment and talents in the comprehensive development and application of precision forging technology of domestic automobile gear parts. Through a large number of design and tests, Luoyang Guanhua precision forging gear general factory successfully formed Fiat front axle spiral bevel gear by precision die forging with near net shape technology, and put it into mass production with good results. This technology has been successfully applied for national patent by Luoyang Guanhua Precision Forging Gear General Factory.
Watanabe m et al. Described the method of precision manufacturing spiral bevel gear by using electrode tooth profile meshing theory, and forged the corresponding spiral bevel gear. Kim sy et al. Simulated the gear precision forging process of automobile steering system by finite element method, and studied the die stress distribution and heat treatment process of forged gear. The simulation results of gear heat treatment surface are generally consistent with the test results. Jung s y et al. Focused on reducing the load of two-step precision forming helical gear, and compared the maximum load obtained by FEM with the load analyzed by the upper limit. This new process can significantly reduce the forming load. At the same time, domestic scholars have also done a lot of research work on gear precision forging. Wang Huajun and others carried out the open die forging process and closed die forging process of lead parts of driving spiral bevel gear at the same time. The results show that the closed die forming process is feasible, which is of great significance for the precision forming of gear parts.
Wang Huajun and others also carried out rigid plastic finite element simulation on the precision forging process of driven spiral bevel gear. The final simulated gear forging has a fully filled tooth profile. At the same time, they described the tooth profile filling mode and the classification of forming stage of precision forging of spiral bevel gear. The blank shape of spiral bevel gear before precision forging not only affects the precision forging process of gear, but also affects the internal quality of forged parts and the service life of forging die. In order to determine the shape, size and size of preform before precision forging of driven spiral bevel gear, Huang Kai and others used the simulation analysis software ADAMS to carry out the principle and steps of die design and dynamic simulation of demoulding process. On this basis, they explored the feasibility of demoulding of forgings. The motion mode, contact force and other parameters during demoulding are defined in ADAMS software. The demoulding motion simulation is carried out to verify that the demoulding of spiral bevel gear with spiral angle of 35 ° is feasible after forging. Zhou Lin of Hefei University of technology designed the centripetal bearing structure concave die to solve the key problem of difficult demoulding of spiral bevel gear forgings.
Zhao Jun and others analyzed the precision plastic forming process and demoulding process of spiral bevel gear with small cone angle by software. The analysis shows that the tooth shape is full and the demoulding process is smooth. Through the finite element analysis of the precision forging process of cylindrical spur gear, Liu Quankun carried out two-dimensional simulation calculation for three design schemes. Finally, the three-dimensional finite element simulation technology was used to verify the feasible scheme obtained by comparative analysis. This scheme has good filling and forming effect. Zhou jiekui and others optimized the punching and skinning structure of spiral bevel gear produced by cold closed precision forging, and obtained reasonable structural parameters. Aiming at the problem of flash in the original process of precision forging of driven spiral bevel gear of automobile rear axle, Tian Fuxiang applied the new process of gear blank precision forging and the new die of precision forging to actual production. The forging has no flash and saves material and energy. At the same time, he also proposed the “one fire two forging” process for rough precision forging of planetary gear, and gave the key points of precision forging die and blank design. The new process is of great significance in prolonging die life and energy saving.