The driven spiral bevel gear of an automobile rear axle is taken as the research object, and its part structure and entity are shown in Fig. 1 and Fig. 2 respectively. The tooth profile parameters are shown in table.
End modulus M/mm | Number of teeth | Average pressure angle | Midpoint helix angle | Spiral direction |
3.7 | 41 | 20 | 35 | Dextral |
The pitch line of the tooth surface of spiral bevel gear is curved, which is different from other spur gears in mechanical transmission. Its transmission is characterized by gradual meshing from one end of the gear to the other end, and the teeth close to it are also gradually transiting during meshing. On the one hand, it increases the contact ratio, on the other hand, it also increases the overlap coefficient. This meshing method can alleviate the impact, make the transmission more stable, have strong bearing capacity and increase the service life of the gear. Because the spiral bevel gear often bears large impact force when transmitting power at the rear axle, it has high requirements for the selection of materials. The spiral bevel gear studied in this paper is made of 20CrMo low carbon alloy structural steel.
According to the structural characteristics of the driven spiral bevel gear shown in Figure 1, the tooth shape of the gear can be directly formed by precision forging. The gear end face requires high precision and is accompanied by 8 M10 threaded holes, which can be machined later. Therefore, the precision forging is designed as the structure shown in figure 3.