Belt drive: main features

The mechanism that transfers the rotation by means of a belt fixed on two shafts (pulleys), and provides a flexible connection between them, is called a "belt drive". These processes occur due to the appearance of frictional forces between the pulleys and the belt belt stretched between them. This type of transmission of the driving force is one of the oldest types of power traction.

By the type of belt used, the belt drive can be carried out using a round, flat, serrated rectangular or tapered belt. Materials from which the belt tape can be made are quite diverse: leather, cotton cloth, rubberized fabric , etc.

The principle of operation is as follows: there are two shafts and a drive belt stretched between them. The pulley, from which the impact is transmitted, is called the leading shaft, and the one to which the traction comes, is driven. The part of the tape that goes to the drive pulley has a stronger tension than the one going to the driven pulley. Therefore, the transmission ratio of the belt drive is the difference in the degree of tension between the two parts of one belt. Thanks to this indicator, it is possible to determine the traction factor of the drive mechanism.

However, here there are a number of its features. For example, the belt tension should be kept constant within the specified limits, since exceeding this value can lead to a rupture of the belt, and an excessively weak tension, on the contrary, will lead to sagging of the belt, slippage may occur. The main function that the belt drive performs is a flexible connection between the two drive shafts without any rigid joints. At the same time, the same amount of force must be transmitted at each time.

If there is a sufficiently large distance between the pulleys, the belt drive may be subject to considerable elastic deformation. This entails stretching the belt and, as a consequence, its sagging. Therefore, in similar situations, the belt can be made of several components, which (due to their small size) will experience smaller stretches.

The efficiency of the belt drive is determined as follows. The power received at the output must be divided into the power that came to the drive, and multiply the result by 100%. The belt transmission can also be characterized by the amount of loss that directly affects the power on the driven shaft of the drive.

Belt drive has the following advantages: low cost, low noise pollution, smoothness, lack of lubrication, easy installation and others. Disadvantages - significant dimensions, the possibility of slippage, fragility and low load-bearing capacity.

The performance of the belt drive increases, if the possibility of slipping is excluded. This parameter depends on the angle of the girth and the degree of tension of the belt.

The angle of the girth is the central angle that pulls the arc formed at the points of contact between the belt and the pulley.