Study on Rolling Process Analysis and Experiment of Small Cone Angle Spiral Bevel Gear

Gear rolling process is a continuous rolling process by rotating and radial feeding motion of rolling wheel. It has advantages of low manufacturing cost, high gear strength and low forming load. The rolling processes of extrusion forming, gear splitting, continuous rolling and reshaping were analyzed by finite element method. The kinematic relationship between the rolling wheel and the forming gear during rolling deformation was studied. The results showed that the meshing motion between the rolling wheel and the billet could be guaranteed when the initial extrusion of the billet was not less than 1 mm. At the rolling gear splitting stage, the equivalent strain of the billet was shown to be related to the deformation of the material, which attained the largest at the root of the tooth. However, the equivalent stress of the billet was found to be dependent on the contact position of the rolling wheel, which has the maximum value at the root of the tooth in the contact area. During the continuous rolling forming stage, the forming load varied regularly and increased continuously with the rolling feed. The tooth profile of the gear was complete after the rolling reshaping process. According to the analysis and calculation results, the structure of rolling forming device was designed. Experiments showed that spiral bevel gears were able to be formed by rolling, and the billet size had an effect on the rolling process. When the size of billet was about 2 mm larger than the dividing circle radius of target gear, the quality of rolled gear was better. The results have important guiding significance for further research rules of rolling forming processes.