Idler Roller Bearings: Living the Good Long Life?

Published: July 01, By Timothy J. Walker Contributing Editor

Idler roller bearings are often overlooked, yet they hold the potential for impressively long service lives, thanks to their relatively easygoing tasks compared to high-speed motor bearings. These often work on coating lines or slitter/rewinders, presenting an opportunity to understand their longevity better.

Joyroll provides professional insights into ensuring that your idler roller bearings can live long and productive lives.

Note

When handling extremely high-tension materials such as steel or heavy paper products, roller drag might be the last thing on your mind. However, for those utilizing idler rollers under less extreme conditions, understanding the life span of bearings can be eye-opening.

Consider this: it's feasible to install an idler roller and not replace its bearing. Diving into engineering handbooks to calculate a bearing's life expectancy using process RPMs along with roller weight and web tension might reveal surprising results—lifespan expectations of 10 to 100 years are not unrealistic! Achieving such longevity requires attention to five key factors:

Size

The right inner diameter of the idler bearing should surpass your shaft's diameter while remaining smaller than the roller's outer shell. A larger diameter bears lesser deflection and promises longer life but may introduce friction. A 1/4 inch diameter is generally the best starting point unless working with very light loads.

Lubricants

In terms of minimal drag, one might think no lubricant is optimal, but this perspective comes with risks. The best options to consider are:

• 5%-25% fill with light oil lubricant
• Using PTFE-based, low-viscosity lubricants over petroleum-based options

It is critical to avoid Zerk fittings on idler rollers as they might lead to a thick grease buildup inside.

Seals

While contact seals can increase friction, without any seals, contamination becomes a risk. Labyrinth seals, which require particles to travel an intricate path to necessarily reach the bearing balls, provide a preferable solution. Some innovative low-drag bearings leverage lubricated felt seals to prevent contamination.

Environment

For bearings, environmental factors like heat, humidity, ozone, and contamination matters significantly. Sufficient lubrication, avoidance of petroleum-based lubricants, and labyrinth seals are crucial for their longevity.

Loads

While bearings are adept at supporting loads perpendicular to their rotation axis, unexpected side loads from misalignment or thermal expansion can jeopardize their lifespan. Strategically designing the mounts can significantly reduce the risks associated with these loads.

I’d like to express my gratitude to Cal Couillard of Componex and Pete Eggen of Webex for their invaluable discussions which contributed to this article. They, like myself, are open to calls about your specific idler roller bearing challenges.

Timothy J. Walker is a web handling expert with over 20 years of experience in web processes, development, and troubleshooting. For personalized advice, feel free to reach out through Idler Roller Manufacturer.

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