For the manufacturing industry, the core of competition in the 21st century will be the competition of new products. How to realize the development of new products with high quality, low cost and short cycle is the key to win this competition. The simulation technology of metal plastic forming process of spur bevel gear is also a multidisciplinary technology under the development of science, technology and economy in the world. At present, the simulation technology of metal plastic forming process has also become one of the important core technologies of die CAD / CAM / CAE technology. In recent ten years, with the rapid development of computer hardware and software technology and the in-depth study of material forming law, the computer numerical simulation technology of material forming process of spur bevel gear has made great progress.
Computer numerical simulation is to obtain the unknown quantities such as the velocity field (or displacement field), strain field, stress field and temperature field of spur bevel gear and die in the specific material forming problem described by the boundary value problem of differential equation through numerical calculation, infer the changes of microstructure and properties and possible defects in the workpiece, and present these analysis results intuitively and dynamically in front of researchers by using computer graphics technology, Through this virtual material processing process, they can understand and test whether the final size and performance of the material meet the design requirements, and optimize and improve the process scheme of spur bevel gear. By using simulation technology, the material forming process design and die design of spur bevel gear can be tested immediately after the preliminary completion, so as to find a feasible or even optimal design scheme, and then complete the detailed design and die manufacturing. In this way, when developing new products of spur bevel gears, the related work such as product design, tooling and die design and manufacturing can be carried out at the same time, that is, concurrent engineering and virtual manufacturing can be realized.
Numerical simulation enriches the research means of plastic forming mechanism, makes the plastic forming technology develop in the direction of intelligence, improves the engineer’s test environment, saves the test cost, shortens the product R & D cycle, makes the forming process of spur bevel gear controllable, and makes the forming process from “technology” to “Engineering Science”. It is an effective means to improve product quality and manufacturing technology of spur bevel gears, and an effective way to improve the competitiveness of enterprises.
The analysis methods of numerical simulation in metal plastic forming of spur bevel gears can be divided into two categories: one is approximate analytical calculation methods, including principal stress method, slip line method, boundary method, upper and lower limit method, work balance method, etc; The other is numerical method, including finite difference method, finite element method and boundary element method. Among them, the finite element method is the most powerful tool for nonlinear analysis and the most popular method for simulating the metal plastic forming process of spur bevel gears.
For the metal plastic forming of spur bevel gears, the finite element method can be roughly divided into four categories: small deformation elastic-plastic finite element method, large deformation elastic-plastic finite element method, rigid plastic finite element method and rigid viscoplastic finite element method. Small deformation elastoplastic finite element method and large deformation elastoplastic finite element method consider elastic deformation and plastic deformation at the same time, while rigid plastic finite element method and rigid viscoplastic finite element method ignore elastic deformation and only consider plastic deformation. The metal plastic forming of spur bevel gear can be divided into volume forming and sheet metal forming. The extrusion forming of spur bevel gear belongs to volume forming. Metal materials produce large plastic deformation and relatively little elastic deformation. It is often solved by rigid plastic or rigid viscoplastic finite element method, which can obtain satisfactory accuracy.
In volume forming, some strain rate sensitive materials of metal at high temperature or normal temperature show material viscosity, which has a great influence on the plastic deformation law of spur bevel gear materials. It is simulated by rigid viscoplastic finite element method; On the contrary, the material is insensitive to the strain rate and is simulated by rigid plastic finite element method. During cold extrusion of gear, the material is not sensitive to the strain rate, which can be simulated by rigid plastic finite element method.