How Does an Idler Sprocket Work?
Most components in power transmission systems have very straightforward names. An idler sprocket is a bit of an exception. Its name implies it does no work, but that isn’t true. It would be more accurate to say it provides no power, but it does plenty of work.
So what does an idler sprocket do? They help maintain a constant tension in the chain that passes over them. A big part of this job is taking slack out of the chain; regulating tension, so to speak. They can do this by having a bearing that rotates independent of the sprocket’s teeth. This enables the movement of the chain to decouple from the movement of the shaft, which lets the sprocket “pull” any excess chain out of the system.
Specific to industrial applications, any time the system moves the chain over a series of sprockets in order to generate the appropriate amount of torque, idler sprockets are there to take the slack out of the chain and restore the necessary chain tension, which is especially useful in systems where the chain makes multiple turns in a system. Without an idler sprocket, the lack of tension in a roller chain could result in slippage and a loss of efficiency, or a failure and necessary downtime for repair.
In addition to systems that make multiple turns, oftentimes there will be ongoing changes in speed or force. Idler sprockets keep the tension in the appropriate range, ensuring minimal losses in the system’s power transmission.
The type of idler sprocket you need depends on the size of the shaft (bore size), the type of chain that will be passing over it (#35, #40, #80, etc.), and the diameter of the sprocket, which is typically measured by number of teeth. Most sprocket selections, including our own, will include more detailed dimensions.
If you’re unsure which idler sprocket you need, request information from MDS and we will help find the solution.
