1. Spur gear and helical gear:

Cylindrical helical gear is used for parallel shaft transmission. The meshing and withdrawing of the gear are carried out along the tooth width at the same time, which is easy to produce impact, vibration and noise.

Cylindrical helical gear can be used not only for parallel transmission, but also for cross shaft transmission (helical gear mechanism). Its characteristics are: large coincidence coefficient, stable transmission, high gear strength, suitable for heavy load. Compared with straight gear, helical gear has axial force.

2. Bevel spur gear and Bevel Helical Gear (bevel gear)

Bevel gear transmission is mainly used for: two shafts intersect transmission, (usually 90 degrees)

The difference between spur gear and helical gear is basically the same as "cylindrical spur gear and cylindrical helical gear", but both have axial force.