The level of gear precision forging technology represents the development of a country’s manufacturing industry to a certain extent. The research on spiral bevel gear abroad started earlier, especially in Germany, the United States, Japan and other countries with more developed industry. In the 1980s, Dana company and Batelle Research Institute in the United States jointly developed the precision forging technology of driven spiral bevel gears and effectively tried the flangeless die forging process. Japan first forged the steel sample of spiral bevel gear with small cone angle, and made some achievements in the experimental research of die forging.
In the 1970s, under the leadership of the Scientific Committee of mechanical industry, many research institutes in China carried out the research on the subject of “automatic production line of spiral bevel gear”. After in-depth and systematic research, the hot precision forging process of gear has achieved remarkable results. In the early 1970s, Shanghai automobile gear factory and Shanghai Mechanized Technology Research Institute jointly tackled key problems and studied the precision forging process of the driving and driven spiral bevel gears of automobile drive axle. The service life of the driven spiral bevel gears precision forged can be more than doubled, and the process results are close to the international level at that time. In the 1980s, Qingdao precision forging gear factory cooperated with Shandong University of technology to develop the precision forging process of large-diameter spiral bevel gear, which realized the direct forging of tooth profile without subsequent cutting.
At first, the research on precision forging technology was mostly based on theoretical analysis and process experiments to analyze the mechanical evolution law and metal flow law of gear in the forming process, and to study the effects of process parameters and die structure on filling and load. Most of the research on the deformation law is force energy analysis. The research on the metal flow law mainly observes the overall flow of the material, while the flow field of the blank surface and internal particles is difficult to observe and count, so only some deformation mechanical parameters can be obtained, It is difficult to visually observe the deformation flow law at each deformation moment in the precision forging process and the impact of changes in various process parameters on forging quality and die life. It is also difficult to optimize process parameters, die structure, blank shape and size, and due to high cost, long cycle and other reasons, It is far from meeting the needs of research and analysis. At the same time, the traditional forging process design is to gradually determine the process parameters through continuous “trial and error” on the basis of knowledge and experience. This way has been difficult to meet the needs of large-scale and personalized production.
With the continuous maturity of numerical simulation methods, the application scope of this technology is gradually expanded, and the ability to solve problems is also gradually enhanced. At present, the software used for numerical simulation of gear precision forging mainly includes deform, SuperForge, autoforge and so on. With the help of numerical simulation technology, the material flow law, forming quality and material defects, stress-strain distribution on the material surface and inside, die forming load, etc. in the precision forging process of spiral bevel gear can be analyzed in detail, so as to provide reliable technical and theoretical support for the formulation of process parameters and die design. Moreover, with the continuous progress of metalology, heat transfer and other disciplines, computer technology and finite element theory, the continuous and rapid development of numerical simulation technology has been promoted. The finite element technology began to develop from macro, single field and general simulation to micro, coupled field and specific special simulation, Finite element numerical simulation technology has become a powerful supporting tool for the research of gear precision forging.
For a long time, researchers at home and abroad
Through theoretical analysis, experimental research, numerical simulation and other methods, the researchers have deeply studied the gear precision forging technology, and achieved fruitful results. At present, the research on gear precision forging technology can be roughly divided into four aspects: forming process analysis, process design and optimization, die structure design, quality and precision control.