What is a Chain Drive and How Does it Work?

Chain drives are a prominent means of power transmission, connecting components over short and long distances. They rank among the top 5 mechanical power transmission methods alongside shaft couplings, belt drives, gear drives, and lead screws. 

Learn more about chain drives, their types, applications, and their pros and cons. Let’s get started!

The working of a chain drive can be deduced as follows:

• Chain drive comprises two or more chains and sprockets. Typically, power is transmitted via a roller chain (a drive chain), which passes over a sprocket gear. 
• The gear’s teeth then engage with the chain’s links, resulting in the gear being turned. This pulls the chain putting mechanical force within the mechanism. 
• Chains also offer the advantage of being suitable for long centre lengths of up to 8 meters. They have the ability to handle speeds ranging up to 25m/s while power transmission up to 110 kW, combined with the potential for even higher power.  
• The teeth on the sprocket wheels are designed to fit the specially shaped cutouts present in the link of the chain. This arrangement ensures a secure connection when the chain is engaged with the sprocket. 
• It prevents the chain from disengaging from the sprocket during operation and maintains the desired velocity ratio.

The different types of chains from an industry standpoint are as follows:

1. Roller Chain

This is the most common type of chain used for mechanical power transmission in different industries, including automotive, construction, agriculture, and many others. A roller chain comprises interconnected short cylindrical rollers that are firmly fastened by side links and propelled by toothed sprockets.

2. Silent Chain

Also called an inverted tooth chain, the silent chain features gear-shaped tooth link plates that engage with sprocket teeth. It is used in different industrial drives where a high-speed, compact, and low-noise drive is required. 

3. Leaf Chain

Leaf chains are predominantly focused on lifting applications. They find their most common use in lifting trucks and are not designed with sprockets integrated into them. Instead, they are intended to run on pulleys, thus ensuring efficient lifting operations.

4. Flat-top Chain

Flat-top chain consists of steel top plates with hinged-like barrels connected by pins and acts as both bearing and beams. They are commonly used on specialised conveyors.

5. Engineering Steel Chain

Engineering steel chains are specially designed for tough conveying applications and are commonly used in bucket elevators, conveyors etc. The design factor in these types of chains includes tensile load capacity, and lubrication requirements, to name a few.

Chain drives find application in various industries due to their reliable power transmission. Some common applications include:

1. Bicycles and Motorcycles

Chain drives play a crucial role in the operation of bicycles and motorcycles. They provide efficient power transmission, enable gear shifting capabilities, and the ability to customise the riding experience in terms of gear ratios and chain length.

2. Automotive Industry

In automotive vehicles, chain drives are used to transmit power from the differential to the rear axle. Compared to driveshafts, chain drives are easy to design.

3. Agricultural Equipment

Chain drives are utilised in agricultural machinery like tractors and irrigation systems. They help to transmit power for operations such as driving wheels, moving conveyor systems etc. 

4. Industrial Machinery

Various industrial machinery, including conveyors, printing presses etc., rely on chain drives for power transmission and to facilitate the movement of materials/ components.

Chain drives offer several benefits. Some of them are listed below:

1. The installation of chain drive is fairly simple, making it a perfect choice for those looking for easy installation techniques. 
2. Chain drives are highly reliable and low wear, providing long-lasting performance. 
3. Chains are easily lubricated, contributing to smooth performance. 
4. Most chains are made of durable metal, offering a good balance between strength and weight. 
5. Chain drives provide smooth operation at various speeds owing to the operating load being evenly distributed among numerous teeth. 
6. Capable of achieving high transmission efficiency, with the potential to reach up to 98%.
7. Owing to its effective and robust design, chain drives can perform well under shock-loading conditions. 

Here are some of the disadvantages of chain drives: 

1. Improper lubrication can lead to wear and tear in chain drives, reducing their overall reliability.
2. Chain drives require regular maintenance to ensure smooth operation and premature wear and tear.
3. Chains have the potential to stretch over time, especially in harsh conditions, which can impact the overall performance. 
4. Accurate installation of chain drives is important for smooth performance. Any misalignment may lead to performance failure. 

Chain drives are quite versatile and provide easy use for power transmission in various applications, including automotive, machinery etc. By properly addressing the maintenance needs and understanding the unique requirements of the applications, chain drives can be a high-efficiency solution for power transmission needs.