| Spiral bevel driven gear is an important driving part of the automobile rear axle main reducer. With the increasing demand of spiral bevel gear, the improvement of quality standards, the control of manufacturing costs, it needs an innovative production technology to meet the market demands. So the precision forging technology of spiral bevel gear has become a research direction of the entire automotive industry. This paper studied on the precision forging technology of automobile rear axle spiral bevel driven gear, which can not only save material, improve machining efficiency, but also can improve the internal microstructure and performance of gear, to ensure the quality of the forging precision forging got can meet the quality requirements of the automobile rear axle spiral bevel driven gear.The main research contents and conclusions are as follows:(1) Studied on the mathematical modeling of automobile rear axle spiral bevel driven gear using CATIA V5R21 three-dimensional modeling software, established a three-dimensional mathematical model of forgings, calculated its volume of 3.15×10-4m3, designed the shape and size of the billet and mold according to the principle of constant volume during plastic deformation.(2) Simulated and analyzed the precision forging technology of automobile rear axle spiral bevel driven gear of using DEFORM-3D finite element simulation software. Systematically analyzed the influence of billet size, forming temperature, forming speed, friction coefficient and the die structure on the forming process, and got the optimal processing scheme. Conclusion: when the selected material was 20 Mn Cr5, the billet size was 125 mm(inner diameter) 175 mm(external diameter) 33.5 mm(height), the slope angle of upper surface was 18 degrees, the forming temperature was 800 ℃, the forming speed was 12.5 mm/s and the lubricant was colloidal graphite, the forming effect was best.(3) Studied on the numerical simulation of warm precision forging process of the optimal processing scheme, and synthetically analyzed the forming process from grid partitioning, the stroke-load curve, equivalent stress, equivalent strain, metal flowing law and temperature. The precision forging technology of automobile rear axle spiral bevel driven gear could be divided into four stages. The four stages were die into blank stage, upsetting stage, tooth forming stage and material overflow stage. We could divide the gear into the large deformation zone(tooth portions) and the small deformation zone(gear) two parts to analysis, then respectively studied the law of the two parts during the forming stage and the feasibility of the technology.(4) Studied on the numerical simulation of cold finishing process, and synthetically analyzed the cold finishing process from grid partitioning, the stroke-load curve, equivalent stress, equivalent strain and metal flowing law. Conclusion: The deformation of cold finishing process mainly occurred in tooth portions, and the biggest deformation area were mainly concentrated on the tooth surface. So cold finishing process could improve the dimensional precision of the gear tooth portions. The load, equivalent stress and equivalent strain of cold finishing process could increase along with the augment of stoke. The maximum load and maximum equivalent stress were both larger than warm precision forging process, but the maximum equivalent strain was smaller than warm precision forging process... |
