Chains and sprockets: how they work together

Chains and sprockets are important elements in the design and mechanics of machines and systems. They are indispensable for mechanical transmission of movement and force. In this blog article, we delve deeply into this topic and take a detailed look at the specific properties of the different types of chains and sprockets.

Chains & sprockets

Chains and sprockets are a very important component in mechanics. They are a fundamental element of mechanics and have developed into an essential component in design over the years. Chain drives offer the option of transferring drive forces and torques in a slip-free, positive-locking and pre-tension-free way.

1. Transferring the drive force from a connected motor to another system.
2. Transporting workpieces by direct or indirect loading.

Chain accessories and tools

Our chain accessories reduce the time and effort required for maintenance in the event of extended chains.

Various tools for developing chain guides or chain suspension mechanisms that are difficult to establish in in-house production processes are also provided to help customers reduce time and costs.

Chains are mechanical parts that are designed to transmit the drive force as a tractive force. In this process, individual links are connected to each other and thus join together to form a continuous row, the length of which is determined by the number of individual links. Chains are available in a wide range of designs, which are selected depending on the application and demonstrate their advantages there. Chains can be used in different designs:

• Roller chain: The links of roller chains consist of an outer link and an inner link, which are connected to each other via a pin. There is a sleeve around the bolt, which in turn is surrounded by a roller. This design makes it possible to minimise friction between the chain and the sprocket and to improve the smooth running properties during movement.
• Block chain: Block chains consist of single-piece chain links that are connected to each other via a pin. They are characterised by high torsional stiffness, but also high weight compared to other chains types. Block chains in mechanics are therefore often made of plastic to reduce weight.
• Conveyor chain: The chain links of conveyor chains, also known as plate chains, have a flat plate on the outside, which ensures positive interlocking of the chain surface. Conveyor chains are often used as a device to transport small or loose materials and workpieces.
• Chain with attachments: Attachments can be mounted on roller chains for transporting smaller workpieces, which, in turn, have shackles attached to them. In this approach, the movement of the chain in transferred directly to the workpieces, which transports them along the running direction.
• Free conveyor chain: This form of chain with double speed is designed for fast transport of workpieces or pallets and, thanks to its special design, enables the pallets to travel at double the running speed of the chain. For this purpose, the chain is usually positioned in a profile on which the guide rollers of the chain rest. The rollers, on the other hand, are freely mounted between the chain guide and act as a support surface for the transported goods. When the transported goods accumulate, this only creates a slight rolling friction between the chain and workpieces, which ensures further transport after the accumulation has been cleared without the chain operation being interrupted.

What is a sprocket?

Sprockets (also called "pinions") are mechanical components used in combination with chains to enable drive forces to be transmitted in the form of a chain hoist. They are flat, disc-shaped components with a ring gear on the outer diameter. The sprocket teeth engage with the chain links to establish a connection between the sprocket and the chain.

How is a chain drive designed?

The design of chain drives is determined by a variety of factors that must be taken into account when selecting the correct chains and sprockets.

Design of roller chains under normal conditions

1. Determine the application specific coefficient. Determine the application-specific coefficient based on the joint design and motor characteristics.

1. Determine the corrected force transmission. The corrected force transmission consists of the force transmission in kilowatts multiplied by the application-specific coefficient. If multiple chains are used, the resulting value must subsequently be divided by the multi-row coefficient.

1. Determine the chain and the number of small sprocket teeth. The corrected power transmission and the speed of the high-speed shaft are used to determine the chain type and the number of required teeth of the small sprocket according to the performance diagram (e.g. DIN 8187) or corresponding efficiency tables. The chain pitch should be as small as possible in order to reduce noise and ensure uniform power transfer.
2. Calculate the number of large sprocket teeth. The number of small sprocket teeth, multiplied by the speed ratio gives the number of large sprocket teeth.
3. Take the shaft diameter into account. When selecting the sprockets, make sure that the diameter of the shaft bore is compatible with the diameter of the shaft it is to be mounted on. If the hole in the sprocket is too small for the shaft diameter, adjust the sprocket or chain accordingly.
4. Determine the intermediate shaft distance between the sprockets. The distance between the two shafts should be selected so that the wrap angle of the chain around the small chain sprocket is at least 120°. The intermediate shaft distance should also be 30 to 50 times the chain pitch. In case of pulsating load conditions, the distance should be reduced to 20 times the chain pitch or less.
5. Determine chain length and distance between shaft centre lines. The formula for calculating the chain length gives the number of chain links. For chain lengths with an odd number of links, the number of links should be increased to the next even number. If an odd number of links cannot be avoided for design reasons, a cranked link must be used.

Design of roller chains under special conditions

When designing roller chains for operation at low speed (with and without shock load) and for operation under special temperature conditions, special design requirements must be observed and included in the calculations. Speed, shock load and/or temperature coefficients must be determined and taken into account when selecting a suitable drive configuration depending on the application type.

How is a chain drive installed?

Chain drives are installed on the driving and driven shafts using the sprockets. Depending on the arrangement and course of the chain, tensioning and guide rollers must be used to prevent the chain from sagging and thus getting caught.

Vertical arrangement

This is a common cause of faults in the chain drive, particularly in the case of vertical shaft arrangement with a shaft offset of over 60°, compared to the horizontal. In vertical arrangement, the small chain sprocket must be installed above the large chain sprocket to prevent the chain from falling off. A suitable tensioner should also be used.

Deflection

The deflection of the chain between the two shafts should be between 2% and 4% depending on the application. A deflection of 4% is the rule, while a deflection of approx. 2% should typically be selected in the following applications:

• With almost vertical transmission.
• With a shaft distance of one meter or more.
• If the chain starts and stops frequently under heavy load.
• If the chain is used in both running directions.

Load change

If load changes take place regularly during use, pre-tensioning must be applied on the chain via suitable tensioning mechanisms (chain tensioners), which prevents vibrations and thus reduces noise and stress on the material.

How is maintenance carried out on a chain drive?

Regular maintenance of a chain drive, if correctly selected and designed, is usually limited to maintaining correct lubrication. There are different methods for lubrication.

In some cases, applying lubricating oils to the chain is not desirable or permissible, for example in the food industry. Maintenance-free versions of chains (usually made of technical plastics) are available for this purpose, which do not need to be lubricated for correct operation.

Apply oil manually with an oil can or brush. Usually at least once a day.

Evenly apply oil 3-4 times over the entire length of the chain while slowly moving the chain on. Make sure that limbs or clothing do not get caught between the chain and the sprocket. Excess oil is flung away during operation after lubrication.

Adjust the drip lubrication so that approximately 5-20 drops of oil per minute are applied to the chain.

It is advisable to place a simple container above the chain for splash protection.

Immerse the underside of the chain in the oil to approx. 10 mm.

Use a sealed oil container. Clean the tank carefully before assembly to remove dust, dirt and other foreign matter. Always ensure that the oil level is correct. Check the fill level regularly and do not overfill the oil container.

Turntable lubrication (skidding plate)

The chain is oiled with a skidding plate. Immerse the plate in the oil to approx. 20 mm. The rotation speed of the plate should be at least 200 m/min.

To prevent overheating, the oil quantity must be adjusted accordingly.

Sprockets

Our sprockets already have spring deflection and a threaded hole, and can be assembled with other parts immediately after delivery. Pre-drilled versions are also available, which allows additional deflections and threaded holes to be added.

Sprockets and chain tensioning wheels

A variety of sprockets and chain tensioning wheels are available, including lubrication-free chains for transferring drive force, chains with attachments for transfer and plastic chains.

Tension pulleys and guide rollers

We offer different types of tension pulleys and guide rollers, including the double bearing type for heavy loads and the small version for tight spaces.

Configure your components

You can configure shafts and other components freely with the MISUMI configurator.

Select the component type and set the desired specifications and characteristics.

CAD library

Use our extensive CAD library to select the optimal part for your components and applications.

Find inspiration in our inCAD library and edit your designs with our SolidWorks add-on “inCADcomponents”.