Belt Drives are a type of frictional drives used for transmitting powers. They are quite popular owing to their high durability and reliability. For most of the power transmission requirements, belt drives are also economical and financially viable. They are comparatively easy to install and maintain and generally are durable and viable in the long run.
Belt drives are used to transmit power between two shafts which do not have a common axis. The amount of power transmitted between the shafts is dependent upon the amount of friction between the two. Factors that determine the power transmission are the velocity of the belt, belt tension between the pulleys and the angle of contact between the pulleys.
For getting the optimal performance and the desired results from the belt drive the selection of the right belt according to the application becomes crucial.Selection of the right kind of belt for a given application will depend upon the type of drive used, operating RPM, Horsepower generation, Diameter of pulleys and center distance, take up design, space available for the setup, shock load conditions, issues with static dissipation, the service life of the belt etc.
Types of Belt Drives:
There are two broad classifications as far as types of belt drives are concerned, they are determined by the amount of power transmission required and arrangement of belts.
Belt Drives according to the power transmitted :
Used in agriculture machines and small machines. The belt speed generally remains in the range of 10 m/sec. Perfect for applications where small power transfer is required.
Used in industrial and semi-industrial applications the power delivery in this set up is of medium range. Highly utilized in machining and similar applications the belt speed in this type of setup ranges from 10 m/sec to 22m/sec.
As the name suggests these are big belt drives used for heavy power delivery. It finds wide application in processes where high transmission power is required. The belt speed in this format of the belt drive is in excess of 22 m/sec. It finds application in running of compressors and similar large machinery.
Belt Drives according to the arrangement of belt :
Open Belt Drive:
In this type of belt drive, the assembly of shafts is parallel and rotates in the same direction. The size of the shaft varies and has a large shaft connected to a small shaft. The power is transmitted from the larger shaft to the smaller shaft, the lower side is known as the tighter side.
Cross belt drive:
In this type of belt drive, the shafts are parallel to each other just like in open belt drive but the belts are in cross configuration and moving opposite to in each other in direction.In this configuration, the same layout of one shaft is bigger than the other is applied. Crossed belt drive has more tension on the side which is acting as the driver i.e. the direction in which the belt is being moved. The side being pulled in known as the tight side and the other one is known as the slack side.
Quarter Turn Belt Drive:
This type of belt drive is also known as right angle belt drive. In this configurations, the shafts are at the right angle and move in one direction.This provides for a unique problem and that is the belt running down the pulley, to overcome this problem the width of the shaft is quarter times more than the width of the belt. Hence the name quarter turns belt drive.
Compound Belt Drive:
As the name suggests, compound belt drive is a complex arrangement of shafts and pulleys where power is transmitted from more than one shaft utilizing a number of pulleys. It is generally used in a complex application environment.