What Is an Idler Sprocket?

An idler sprocket is a gadget used to maintain the strain in a chain or chain drive system. Often comprising nothing more than a sprocket mounted on a springtime tensioned arm, the idler sprocket pulls against the chain in a continuous way to keep the chain tight at all times. The size of the sprocket used in an idler sprocket assembly does not have any influence on the functionality of the chain travel; however; a more substantial sprocket will most likely last longer due to the slower speed of the sprocket, which saves wear on the sprocket’s bearings. Maintenance for the idler assembly is often no more than an occasional greasing of the sprocket’s bearings.

When traveling a machine by chain, the tension of the chain must be kept at a constant to avoid the chain coming from the drive sprockets. By installing an idler sprocket in the get program, the chain is usually kept taut without being over-tightened. Working a chain in an over-restricted condition can result in premature bearing and chain failing while an idler sprocket positioned in the system is often a way to greatly extend the life of the chain, sprockets and the bearings on the machine’s sprocket shafts.

The ideal installation of the idler sprocket is on the contrary side of the chain between the travel sprocket and the driven sprocket. The application should place the idler sprocket ready which has the sprocket pressing or pulling the chain towards itself since it loops the two major sprockets in a form like the letter B. This design allows the pulleys to draw the chain hard without hindering the idler at all as the drive chain passes over the sprocket. If a condition presents itself which needs the get to exert surplus strain on the drive chain, the idler will flex against the chain, allowing it to expand while remaining in contact with the travel sprockets.

While the vast majority of idler sprockets are manufactured of steel, many materials are used to produce an idler sprocket. Many poly or composite sprockets have been used with great success and some wooden sprockets have also been used on some machinery without concern. Many machines, in an attempt to reduce the use on the drive chain, use an light weight aluminum, cast iron or steel sprocket coated in a nylon materials. The metallic hub allows the idler sprocket to remain very strong as the nylon covering is certainly gentle on the chain links.