Belt drives are used to transfer rotational motion from one shaft to another. Both shafts may rotate at same or variable speed. In this article we will discuss what is belt drive, it’s types, advantages and limitations.
What is Belt Drives ?
Belt drive consist of two or more pulleys connected with belt in tension. Similar to gears, belt and pulley drive offers one of the best way to transfer power from one shaft to another.
For example, belt drives are used in cars to deliver power to various components such as alternator, air conditioning system etc.
Belt Drive Working Principle
A simple belt pulley system consist of a driver pulley and driven pulley. When driver pulley is rotated it causes pulling action due to friction. This pulling effect rotates the driven pulley in the same direction of driver pulley.
This Pulling effect results in the tight side and slack side on belt pulley system.
Types of Belt
Based of construction belts can be classified in following four types.
- Flat Belt
- Round Belt
- Timing / Teethed Belt
Flat belt has rectangular cross-section. They are used to transfer power from one shaft to another at relatively larger distance. Frictional force is used to transfer power from one shaft to another.
Advantages of Flat Belt Drive
- Low Cost and Simple to Manufacture.
- Transfer Power at relatively larger Distance.
- Can withstand High Load
Disadvantages of Flat Belt Drive
- Not Suitable for small distance.
- High Slippage and Creep results in loss of power.
- Constant Velocity ratio between driver and driven pulley can not be achieved.
- High Noise
- Low Mechanical Efficiency
V-Belt has trapezoidal cross section and used in grooved pulley. They are used to transfer power from one shaft to another at small distance.
Advantage of V-Belt Drive
- Used to transfer power at low distance.
- Low Slippage and alignment problem.
- Can transfer high power at high speed.
Disadvantages if V-Belt Drive
- High Cost compared to flat belt drive.
- Can not be used to transfer power at longer distance.
Round belt have a circular cross-section and used in pulley with round groove.
Advantages of Round Belt
- Used to transfer power at relatively larger distances.
- Low Cost
- Less Wear
- High Mechanical Efficiency ~ 95%
Disadvantages of Round Belt
- High Slippage
Timing belt have teeth that fits into toothed pulley. They are also known as positive transfer belts. We suggest you to read this article for more details on timing belt drive.
Advantages of Timing Belt
- No Slippage
- Constant velocity Ratio.
- Reduced Noise
- High mechanical efficiency ~ 98 %
Disadvantages of Timing Belt
- High Cost
- Initial alignment with timing pulley is required
Types of Belt Drive
Based on how motion is transferred between two shafts and shaft arrangements. Belt drives can be classified in following types.
- Open Belt-Drive
- Cross Belt-Drive
- Stepped Cone Pulley
- Jockey Pulley Drive
- Fast and Loose Pulley Drive
To sum up, belt and pulley is one of the cost effective solution to transfer power from one shaft to another at relatively small and larger distances. For example, pulley drive are used in car to transfer power from engine to other car parts.
Got Questions? We will be happy to help.
If you think we missed Something? You can add to this article by sending message in the comment box. We will do our best to add it in this post.