Duralon® Self-Lubricating Composite Bearings

Category: Bearings

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agriculture

Bearing

duralon

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Agricultural equipment endures extremely dirty environments. Metallic sleeve bearings -- commonly used in pivoting (oscillating) applications – require external lubrication with grease or oil to function properly and efficiently. However, a film of oil on the shaft acts like a magnet for environmental dirt and other contaminants.

This dirt and oil combination can gum up your operation by accumulating in the clearances between the bearing I.D. and the shaft. It can also act as an abrasive, prematurely wearing out bearings or other components. Often, these contaminants are a byproduct of the application, such as a baler or combine, where bits of organic material from the crop being processed can be ground into fine particles and accumulate within the bearings.

Sometimes, it’s due to external applications, such as a walking beam, articulating towing hitch, seed planter or fertilizer. In these cases, in addition to the contamination created by crop residue, soil and chemical fertilizers may also contaminate the mechanism. And if the equipment is stored outdoors, weather may also play a role, with rain or snow washing off the lubricant (and, as a consequence, contaminating the ground on which it’s stored).

Another factor is downtime. When equipment sits idle (i.e., between harvests), it’s critical to relubricate all joints prior to using the machine.

With non-metallic, composite construction, Duralon^®bearings are designed to resist contamination. Made with a woven TEFLON^® fiber and polyester fiber self-lubricating fabric, this line of bearings is supported by a continuous fiberglass filament and epoxy resin-filament wound matrix.

While typical lubricant grease and oil films are limited to maximum bearing pressures of 5,000 psi, Duralon bearings are routinely used in applications dynamically loaded to 20,000 psi. The radial ultimate crush strength of the bearing material is a function of wall thickness. For a .125" wall section, the radial ultimate strength exceeds 77,000 psi. In addition, these bearings can sit static, under load, for extended periods without cold flow (creep), or requiring routine maintenance prior to startup.

Because there is no oil film, dirt and debris can’t accumulate on the shaft. In applications where dirt and debris can be trapped within the mechanism, we use seals to minimize the impact of contamination.

Duralon’s non-metallic material is resistant to water and many chemicals, including lubricants and hydraulic fluids. However, a corroded shaft may prematurely wear out a bearing. For situations where corrosion is an issue, we recommend using a corrosion-resistant shaft.

The bearing material is also an electrical insulator, and it’s lightweight, weighing 75% less than steel, and 30% less than aluminum. Originally designed to replace lubricated bronze bearings in pivoting applications, Duralon is also well-suited to linear applications and slow-speed, full-rotation applications.

If you have questions, email [email protected]. For videos and other demos, visit our YouTube channel.

TEFLON® brand fibers are manufactured by Toray Fluorofibers (America); TEFLON® is a registered trademark of the DuPont Company used under license by TFA.

Dennis Bozych

Dennis Bozych is Principal Engineer for the Rexnord Filament Bearing business. He has been with Rexnord 47 years in the commercial and aerospace bearing business. For the last 36 years he has been involved solely with the design, development and application of Rexnord’s Tuflite® and Duralon® self-lubricating non-metallic filament wound bearings.