What is Belt Drives: Type Advantages and Disadvantages

Belt drives transfer rotational motion from one shaft to another. In this, both shafts may rotate at the same or variable speed. In this article, we will discuss what is belt drive? it’s types, advantages, and disadvantages of belt drive. Click this link to know the various types of gear and their application.

What is Belt Drive?

belt drive are used in cars to deliver power to various components such as alternator, air conditioning system etc.
Example of the use of Belt Drive in an Automobile

Belt drive consists of two or more pulleys connected with a belt in tension. Similar to gears, belt and pulley drive applications is to transfer power from one shaft to another. For example, belt drives are used in automobiles to deliver power to various components such as an 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
Belt-Drive Working Principle

A simple belt pulley system consists of a driver pulley, driven pulley, and a belt. When the driver pulley rotates, it causes pulling action due to friction. The pulling effect rotates the driven pulley in the same direction as the driver pulley and results in the tight-side and slack-side on the belt pulley system.

Types of Belt used in Belt Drive

Here are the four different types of belts used to connect and rotate one shaft from another shaft. Each of these belt types has its advantages and limitations.

  1. Flat Belt
  2. V-Belt
  3. Round Belt
  4. Timing / Toothed Belt
Flat Belt

A flat belt has a rectangular cross-section and has application to transfer power from one shaft to another shaft at a relatively large distance. In this, the frictional force between the flat belt and pulley transfers power between shafts.

Flat Belt
Advantages of Flat Belt Drive
  • Low Cost and simple to manufacture.
  • Transfer Power at a relatively large distance.
  • Can withstand high load
Disadvantages of Flat Belt Drive
  • Not Suitable for small distances.
  • High Slippage and creep results in loss of power.
  • You can not achieve a constant Velocity ratio between driver and driven pulley.
  • High Noise
  • Low Mechanical Efficiency
V-Belt

V-Belt has a trapezoidal cross-section and is used in the grooved pulley. They have an application to transfer power from one shaft to another at small distances.

V-Belt
Advantage of V-Belt Drive
  • Transfer power between small distances.
  • Low slippage and alignment problem.
  • Can transfer high power at high speed.
Disadvantages if V-Belt Drive
  • High Cost compared to flat belt drive.
  • V-belts can not transfer power at a longer distance.
Round Belt

Round belts have a circular cross-section and are used in round groove pulleys.

Advantages of Round Belt
  • Transfer power at relatively larger distances.
  • Low cost
  • Less wear
  • High mechanical efficiency ~ 95%
Disadvantages of Round Belt
  • High slippage
Timing Belt

The timing belt has teeth that fit into the toothed pulley. They are also known as positive transfer belts. Click this link for more details on timing belts.

Timing belt is a type of synchronous belt consisting of teeth similar to gears. It is used to transfer synchronous motion from one shaft to another shaft.
Timing Belt
Advantages of Timing Belt
  • No slippage.
  • Constant velocity ratio.
  • Reduced noise.
  • High mechanical efficiency ~ 98 %
Disadvantages of Timing Belt
  • High cost.
  • Timing belt requires initial alignment with the timing pulley.

Types of Belt Drive

According to how motion transfers between two shafts and shaft arrangements. Here are the five different types of Belt drives.

  • Open Belt-Drive
  • Cross Belt-Drive
  • Stepped Cone Pulley
  • Jockey Pulley Drive
  • Fast and Loose Pulley Drive
Open Belt-Drives
Open belt drive is used to drive pulley in the same direction.
Open Belt Drive

As shown in the above image, In the open belt drive pulley and belts are arranged in a way, the driver and driven pulley rotate in the same direction.

Crossed Belt Drive
Crossed belt drive are used to drive shaft in opposite direction.
Cross Belt Drive

As shown in the above image, Crossed belt drive belts are arranged in a way the drive and driven shaft rotates in the opposite direction.

Stepped Cone Pulley
stepped cone pulley are used when speed of the driven shaft need to changed very frequently.
Stepped Cone Pulley Drive

As shown above, stepped cone pulleys consist of steps in the pulley. They have applications when the speed of the driven shaft needs to change very frequently.

Jockey Pulley Drive
Jockey are used when center to center distance between two shaft is small.

Jockey Pulley drives have applications where the center to center distance between two shafts is small.

Fast and Loose Belt Drive
Fast and Loose Pulley drive are used in applications when driven shaft need to stop or start quickly.
Fast and Loose Pulley Drive

The Fast and Loose Belt Drives have applications where the driven shaft needs to stop or start quickly. As shown in the image, the Fast and Loose belt drive consists of free and fast pulleys. The free pulley rotates freely on a machine shaft, whereas a fast pulley is connected with the machine shaft.

To sum up, belts and pulleys are cost-effective solutions to transfer power from one shaft to another at relatively small and larger distances. For example, pulley drives are used in cars to transfer power from the engine to other car parts.

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