Straight bevel gears are easy to process and do not produce axial force in transmission, so they are widely used in the transmission of intersecting axis gears. However, in the process of high-speed transmission, each pair of teeth engage rapidly at the same time, which is easy to produce impact, resulting in unstable transmission, poor bearing capacity and high noise. The spiral bevel gear is meshed continuously and smoothly from one end of the tooth to the other end, which avoids the above problems and can make up for the defects of the straight bevel gear.
Compared with the straight bevel gear, the pitch line of the tooth surface of the spiral bevel gear is curved, which can be roughly regarded as being formed by cutting the straight bevel gear into countless thin slices and twisting it to tilt with the bus. In the transmission process, the teeth of the spiral bevel gear pair are gradually in contact from one end to the other end. In the transmission, at least two or more teeth mesh at the same time. The number of teeth engaged is more than that of the straight bevel gear, which increases the contact ratio, that is, the overlap coefficient. Therefore, it has the characteristics of small impact, stable transmission, low noise and strong bearing capacity. It is widely used in aerospace, automobile and various precision machine tools. Therefore, the design and manufacture of spiral bevel gear has occupied a very important position in the machinery industry.
Due to the existence of helix angle, the overlap coefficient increases, the load specific pressure decreases, and the wear is more uniform. At the same time, it also increases the load capacity of the gear, that is, it prolongs the service life of the gear. Large transmission ratio can be realized, and the number of small wheel teeth can be reduced to five teeth. It can adjust the radius of the cutter head and correct the contact area by using the curvature of the tooth line. Tooth surface grinding can be carried out to reduce noise, improve contact area and improve tooth surface finish.