Development of gear precision forging technology

Precision forging technology has obvious advantages: low cost, high efficiency, energy and material saving, high precision and so on. There are many classification methods for precision forging, including high-speed precision forging, general precision forging, slow precision forging, etc. according to the flow condition of metal in the mold cavity, there are semi closed, closed and open precision forging processes; According to the forming temperature, there are superplastic, medium temperature, high temperature precision forging, etc; According to the classification of forming technology, it can be divided into shunt forging, isothermal forging, compound forming, etc.

As early as the middle of last century, BLW company in Germany obtained the patent of gear precision forging technology. The company uses friction press for precision forging, which can process gears with modulus of 2-12 and diameter of 25.4-300mm, reaching grade 6 accuracy. Subsequently, the United States, Britain, France, Japan and other countries successively began to introduce the gear precision forging technology of BLW company and apply it to mass production. In the 1970s, Mitsubishi Metal Co., Ltd. of Japan adopted precision forging technology to realize the mass production of driven spiral bevel gears for automobiles and tractors, and the maximum diameter of the gears can reach 180mm. Subsequently, BLW also mass produced driven spiral bevel gears with a diameter of about 220mm. In the 1990s, Japan forged steel samples of small cone angle spiral bevel gears. At the end of last century, Birmingham University, together with gear manufacturers, material suppliers and users, jointly developed the precision forging technology of cylindrical spur and helical gears. Today, National Corporation of the United States, Schmidt Corporation of Switzerland, Komatsu Corporation of Japan, Schuler Corporation of Germany and BLW corporation are all international well-known precision forging companies. Their spiral bevel gears are of superior quality The precision forging process of small and medium-sized spiral bevel gears has achieved mass production and began to be applied in the automotive industry.

The history of domestic gear precision forging technology can be traced back to 1967. Represented by Shanghai automobile gear factory and Shandong Institute of technology, friction presses are used to produce precision forged gears in large quantities. In the early 1970s, China has used this technology in the production of straight bevel gears for automobiles and tractors. In the late 1970s, the Ministry of machinery industry led Shanghai Institute of mechanical manufacturing technology, Shandong Institute of technology, Beijing Institute of electromechanical technology and other units to cooperate in the scientific research of spur bevel gears. After decades of development, at present, Chinese enterprises have mastered the relevant process and die technology. The domestic precision forging technology of spur bevel gear is gradually mature, and is developing in the direction of energy conservation, environmental protection, high precision and automation. China is the country with the largest production and use of bevel gears in the world. The core technologies such as die design and mass production have been mature, and the talent team is very strong. However, there are still many problems in the precision forging process and die of large spiral bevel gears, which are difficult to be widely popularized in the field of production and processing.