An idler sprocket is a gadget used to keep the tension in a chain or chain drive system. Often consisting of only a sprocket installed on a spring tensioned arm, the idler sprocket pulls against the chain in a constant way to keep carefully the chain limited all the time. The size of the sprocket found in an idler sprocket assembly does not have any influence on the functionality of the chain get; however; a more substantial sprocket will most likely last longer because of the slower velocity of the sprocket, which saves use on the sprocket’s bearings. Maintenance for the idler assembly is often only an intermittent greasing of the sprocket’s bearings.
When traveling a machine simply by chain, the tension of the chain should be kept at a constant in order to avoid the chain approaching off of the get sprockets. By setting up an idler sprocket in the drive system, the chain is normally kept taut without being over-tightened. Working a chain within an over-tight condition can result in premature bearing and chain failing while an idler sprocket placed in the system is often a method to greatly prolong the life of the 
chain, sprockets and the bearings on the machine’s sprocket shafts.
The ideal installing the idler sprocket is on the contrary side of the chain between your drive sprocket and the driven sprocket. The application should place the idler sprocket in a position that has the sprocket pushing or pulling the chain towards itself as it loops the two main sprockets in a form like the letter B. This style will allow the pulleys to pull 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 drive to exert extra pressure on the drive chain, the idler will flex against the chain, allowing it to expand while staying in touch with the travel sprockets.
While the vast majority of idler sprockets are manufactured of steel, many materials are used to manufacture an idler sprocket. Many poly or composite sprockets have already been used in combination with great achievement plus some wooden sprockets have also been applied to some machinery without issue. Many machines, in an attempt to reduce the wear on the drive chain, use an aluminum, cast iron or steel sprocket coated in a nylon materials. The metallic hub allows the idler sprocket to remain very strong while the nylon covering is definitely gentle on the chain links.