Although the production efficiency of cross wedge rolling forming active spiral bevel gear blank is very high, the material utilization rate is not very high due to the existence of material head. At the same time, due to the fact that cross wedge rolling is not fully constrained in the circumferential direction, the radial dimension error of the tie piece is large, the surface quality is not high, and the workpiece has slight bending. The material utilization rate of driving spiral bevel gear blank formed by cross wedge rolling vertical forging method is higher than that of cross wedge rolling. The surface quality, coaxiality, dimensional accuracy and defects of gear blank have been improved compared with cross wedge rolling process. However, because the shaft is still manufactured by cross wedge rolling, the dimensional error of the shaft still exists. At the same time, due to the pit at the end of the workpiece during cross wedge rolling, it needs to be filled in the vertical forging process, which affects the quality of the product to a certain extent.
In order to improve the dimensional accuracy of the formed shaft and avoid the pit filling process, the feasibility of producing driving spiral bevel gear blank by extrusion vertical forging is considered. This process studies the effect of hot forming and cold forming to produce driving spiral bevel gear blank.
The forming technology of driving spiral bevel gear blank by extrusion vertical forging is studied. The forming effects of hot forming and cold forming are studied. During forming, the step shaft of the driving spiral bevel gear blank is extruded by extrusion process in two times. By comparing and analyzing the forming effect, it is concluded that both cold and hot extrusion methods can form a better shaft of driving bevel gear blank. During cold extrusion, there are high requirements for equipment and die quality. After vertical forging, the conical head of gear blank is forged, and the forming quality is also good. By analyzing the die load, equivalent stress, metal flow and damage value in the forming process, it is concluded that the driving spiral bevel gear blank formed by extrusion vertical forging method is the best one of the three processes studied in this paper. The material utilization rate is basically similar to that of cross wedge rolling vertical forging method. However, the production efficiency is far lower than that of cross wedge rolling and cross wedge rolling vertical forging.