There are many types of gear transmission, which can be divided into different types according to different classification methods.
1.According to the transmission ratio
According to whether the transmission ratio of a pair of gear transmission is constant, it can be divided into fixed transmission ratio and variable transmission ratio gear transmission. In variable ratio gear transmission mechanism, the gear is generally non-circular, so it is also called non-circular gear transmission. It is mainly used in some machinery with special requirements. The gears in the gear transmission mechanism with fixed transmission ratio are round, so it is also called circular gear transmission.
There are many types of gear transmission with fixed transmission ratio. According to whether the rotation axes of the driving and driven wheels are parallel, it can be divided into two types, namely plane gear transmission and space gear transmission.
2.According to the tooth profile shape
According to the shape of tooth profile curve, it can be divided into involute gear transmission, cycloidal gear transmission, circular arc gear transmission and parabola gear transmission. Among them, involute gear transmission is the most widely used.
3.According to working conditions
According to different working conditions of gear transmission, it can be divided into closed gear transmission, open gear transmission and semi open gear transmission. In open gear transmission, the teeth are exposed, and the dust is easy to fall on the tooth surface; In closed gear transmission, the gear teeth are enclosed in the box, which can ensure good working conditions and is widely used; The working conditions of semi open gear transmission are better than that of open gear transmission. The large gear is partially immersed in the oil pool and has a simple protective cover, but there are still foreign objects invading.
4.According to tooth surface hardness
According to the hardness of tooth surface, it is divided into soft tooth surface gear transmission and hard tooth surface gear transmission. When the tooth surface hardness of two wheels (or one of them) is ≤ 350hbw, it is called soft tooth surface transmission; When the tooth surface hardness of both wheels is > 350hbw, it is called hard tooth surface transmission. Soft tooth surface gear transmission is often used in general medium and low-speed gear transmission with low precision requirements, and hard tooth surface gear transmission is often used in gear transmission with strong bearing capacity and compact structure.
Although there are many types of gear transmission, involute spur gear transmission is the simplest and most basic type.