Do you notice any signs of wear on the inside of the chain side plates or on the sides of the sprocket teeth? Some wear and stretching of the roller chain is to be expected during operation. However, when the wear is excessive or abnormal, as in the previous case, we advise you to take a closer look.
Replacing parts more frequently than necessary is not a sustainable practice. Keeping your roller chain in tip-top shape is essential for a long service life. This is why it is essential to find the root cause of abnormal wear and fix it.
Unusual wear patterns on chain plates or sprocket teeth typically result from an alignment problem. When chain drive sprockets are not aligned correctly, the chain will move off-center and wear unevenly. Ultimately, this can lead to component failures, excessive noise and slow work.
Let's look at the things you should consider.
How was the chain drive installed?
When installing a chain drive, it is critical to ensure that the shafts and sprockets are aligned, with the sprockets securely locked onto the shaft. The axes must be angularly aligned, that is, they must be parallel to each other, which is checked by measuring between them at several points. The sprockets must be axially aligned, which means that the faces of the sprockets are aligned with each other. These alignments should be checked using a laser or ruler.
Neglecting to align the shafts or sprockets will force the roller chain to bend to accommodate any misalignment present. This will cause the face of the sprocket to touch the inside of the chain plate. This uneven contact will make it more difficult for the chain to disengage from the sprocket, resulting in increased friction and excessive wear.
Example of pinion tooth wear pattern:
The sprockets must be centered and parallel so that the roller chain moves smoothly over the teeth. Anything less will lead to excessive wear and eventual replacement before scheduled maintenance. In this case, remove the chain and realign the sprockets. If necessary, replace parts and make sure they are aligned correctly to prevent recurrences.
Check for interference in the chain
After checking the sprocket alignment, it's time to take a look at the roller chain. Even though the sprockets and shafts are aligned in each plane, a blockage can still push the roller chain out of position.
Examine your system carefully to see if there is anything that might be bothering you. Remove items that interfere with the current. In situations where the impediment is unclear or not movable, consider installing a chain guide.
Problems with the vibrating sprocket
One of the telltale signs of excessive vibration in the drive system is noise. When the roller chain creates an unusual noise and the sprocket appears to rotate in a non-linear path, there is an obvious problem. It is very likely that the pinion bore is no longer (or never was) completely perpendicular to the pinion face. This can occur on both a smoothbore sprocket and a socket version.
When this occurs on a sprocket, it was probably assembled incorrectly. Proper installation procedures will eliminate this problem. Regarding smooth bore sprockets, there are two possible causes. Inaccurate finishing of the sprocket hole will cause the sprocket to rotate imperfectly. An undersized shaft can also cause imbalance and vibration. When securing a sprocket with set screws, an undersized shaft can cause an inaccurate, yet slight, adjustment of the sprocket.
The solution will vary depending on the cause. Reinstalling the bushing in the pinion is an easy fix. However, for smooth bore sprockets or undersized shafts, a component replacement will be required to return the chain drive to normal operating conditions.
