Composite bearings for agriculture

Greaseless Bearings

no grease gunBecause all Polygon composite bearings are permanently self-lubricated, greasing maintenance is eliminated and the prime candidate for premature bearing failure is removed.

In the example shown above, a larger Bourgault wheat seeder was made possible because accessibility for greasing was no longer needed.  Customers appreciated the reduced maintenance time as well not needing to crawl over equipment to find inaccessible greasing zerks.

No Grease Fittings

Zerk fittings and other grease retention and delivery systems are not needed and can be eliminated for cost savings.

High Temperature

Polygon's High Temperature bearings are designed for environments over 475°F (245°C) or where thermal expansion stability is critical. No specialized high temperature grease is required.

No Grease Contamination

Because lubricants are not needed, the danger of them producing contamination is removed. The foodservice industry will especially appreciate not needing to purchase food-grade lubricants, as well as the reduced maintenance required.

Corrosion Resistant

Because Polygon's composite bearings are made with high-grade polymers and fibers, there are no metal constituents. This eliminates corrosion and opens them to use in caustic environments.

PolySlide® composite pneumatic and hydraulic cylinders are also are highly corrosion resistant and are a perfect combination for use with guide rod bearings.

Bearing Break-in

ptfe bearing cutawayThe bearing surface is composed of a uniquely designed woven structure of PTFE super-filaments, which exhibit tensile strengths twenty times greater than PTFE resins. As a result, the bearing is not subject to cold flow under high loading conditions. These PTFE super-filaments are also the primary mechanism for allowing the PolyLube product to operate in a true self-lubricating mode. No secondary lubrication is necessary, even during start-up conditions, due to the film transfer self-lubrication process.

As the bearing joint begins service, the PTFE undergoes a phase change and smears around the mating pin surface. As the PTFE film develops, it transfers from the inner diameter to the outer diameter of the pin, smoothing out any macroscopic surface imperfections and allowing the bearing to have a very low coefficient of friction and minimal long term wear, even under high loading conditions.

In some conditions, as much as 0.001" of wear may occur during the break-in period, while in other operations, break-in wear may be negligible. The elapsed time for break-in is PV (Pressure and Velocity) dependent. The equilibrium wear rate varies from operation to operation, due to a number of factors including: loads, speeds, shaft hardness, material, and shaft surface finish. For more specific guidance on the break-in period to anticipate given your specific application, please contact a PolyLube application engineer.

Following the break-in period, the wear rate stabilizes, remaining relatively constant for the bearings’ life. Testing at 22,500 pounds with a 50° oscillation angle resulted in stable wear under 0.005" at over 1.5 million cycles.

PolyLube bearings are designed to minimize wear; however, the bearing wear is affected by the general operating conditions, such as speed, sliding distance and load. With intermittent rotation or oscillation, radial wear should be negligible over thousands of hours. Hard chrome plating gives excellent wear performance and protects the shaft from corrosion. Coatings such as chrome, electroless nickel, or nitro carbonizing are all common treatments for shaft materials used with PolyLube bearings.

As the bearing begins to cycle, the initial coefficient of friction will increase in relationship to the longer term, “broken-in” frictional values. This is due to the fact that a small layer of resin, generated by the manufacturing process of the composite backing, is being slowly worn away.

film transfer

The above schematic represents a detailed perspective on how the surface condition of the mating pin changes both before and after the PTFE film transfer process.


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Disclaimer

Any ratings are typical for design purposes. Your design parameters may affect final ratings. Consult with a Polygon sales engineer for guidance. Final testing and approval is the customer's responsibility for their application. This information is derived from our testing and published data. There is no assurance of these properties, or warranty provided that these products are suitable for any particular purpose or operational situation.

Polygon certifies that their product will be free from material defect. Polygon will not accept any liability for loss, damages, or costs from use or misuse of our products.

Specifications are subject to change, and may be affected by our continual process of improvement. Changes may be made without prior announcement.

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