Common types of mechanical transmission include friction wheel transmission, belt transmission, chain transmission, gear transmission, worm gear transmission, spiral transmission and other types.

Belt transmission can be divided into flat belt transmission, V-belt transmission, V-belt, circular belt, toothed belt and other types of belt transmission according to the different cross-sectional shapes.

The wheel used to install the belt in the belt drive is called the belt wheel. Commonly known as pulleys. The pulleys are installed and used in pairs, one is the driving wheel and the other is the driven wheel.

According to the working principle of transmission, mechanical transmission can be divided into transmission and friction transmission.
The advantages are reliable work, long life, accurate transmission ratio, high transmission power, high efficiency (except worm drive), and wide speed range. The disadvantage is that the precision requirements for processing, manufacturing and installation are relatively high.
Friction transmission works smoothly, with low noise, simple structure, low cost, and overload protection. The disadvantages are external dimensions, inaccurate transmission ratio, reduced transmission efficiency, and component life loss.

Belt drive is a type of friction drive.

The working principle of the belt drive is that the belt is tightly sleeved on the driving wheel and the driven wheel, so there is a positive pressure on the contact surface of the belt and the wheel. When the prime mover drives the driving wheel to rotate, friction is generated between the contact surface of the belt and the driving wheel. , So that the driving wheel pulls the belt, and then the belt pulls the driven wheel to transmit the torque and motion on the driving shaft to the driven shaft.

From the principle of belt transmission, it can be known that the role of the pulley is to transmit torque and movement through the transmission belt.