Differences between Greaseless Bearings and Lubricated Bearings

October 11, 2016

When greasing the proverbial wheels of industry, maintenance engineers take note of bearing housings that require lubrication. In this manner, drive shafts and their associated bearings are optimized, frictional heat is minimized, and equipment lifespan is assured. Greaseless bearings add an interesting element to this engineering conundrum, for no lubrication maintenance schedule is required when these rolling elements are employed.

The Advantages of Greaseless Bearings 

If the majority of our hydrocarbon reserves are used to make fuels and plastics, the next heaviest application area has to be the lubrication agents that keep our machinery moving. But grease-free bearings remove this need from the friction-reducing equation, which means the environment receives a happy boost. Incidentally, a maintenance-free operation is also a fine feature to promote in this situation, for maintenance routines do incur lengthy periods of expensive downtime.

It’s Not All a One-Way Street 

Unfortunately, not every machine uses this design, not when plain ball bearings are so well established. Special alloys with graphite or polytetrafluoroethylene films are manufactured and added to the races of these bearings, and they exhibit special solid lubricating properties. Of course, even when less expensive variations use solid lubricants and special feed inlets to partially replicate this expensive film, well, complex variables enter the mix, and this introduces a degree of unpredictability to the fixture that no longer makes the system superior to the lubricated bearings. In short, purebred greaseless bearings are a fine addition to a working system, but they’re not always the most economically viable alternative.

New Technologies Work in Harmony with the Old

Coming down the pipeline soon, new greaseless bearings are literally freeing themselves of their cages. Cageless, the new rolling element design incorporates a series of divots and cutouts within the locking rings of the bearing. These special physical features stop contact points from rubbing against each other, so frictional behavior is attenuated. Meanwhile, traditional ball bearings still rule the roost thanks to lubricating compounds that are formulated with advanced additives. These oily mixes exhibit low viscosity ratings, which renders the compound drag-free. As drag is eliminated, the synthetic liquid also goes to work on creating a thin uninterruptible film between each contact point. The result is a cool-running rolling element that can handle the heavy loads of a turbine or other heavy mechanical cargo.

Again, even these improved lubricants make the difference by employing special fluorocarbons and other exotic additives, but they will work very well until greaseless bearings dominate every radially active application.

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