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Gizmag tells us about how a Japanese company, Coo Space, has developed an innovation in ball bearings that will allow the balls to automagically space themselves out. That will lead to vastly reduced friction which, in turn, will lead to the elimination of the necessity to grease the bearing to reduce the friction. This is potentially a huge development across all forms of industry.
The Autonomous Decentralised Bearing (ADB) puts a small indentation, or groove, into the outer bearing race. As the balls slide over this tiny groove, they slow down ever so slightly, and then speed back up. This does nothing to affect the bearing's regular performance, but if two balls are touching each other as they cross over the groove, the first ball's deceleration puts a tiny brake on the second ball, which separates the two as they go around the races.
It's an incredibly simple and tiny change, but it does a remarkable job.
...
Without the need for a cage, you can run these bearings un-lubricated, and that's where the real performance benefits come in. Coo Space claims the ADB experiences as little as 10 percent of the friction of a regular ball bearing
Here is a YouTube video of the bearings spacing themselves out within the races.
[Editor's Comment: Original Submission]
(Score: 3, Interesting) by carguy on Wednesday May 27 2015, @10:35AM
For anyone having trouble understanding how the addition of a groove can change the speed of the ball bearing, it might help to relate it to this once-popular toy, http://www.toysrus.com/buy/active/shoot-the-moon-4099084-2323497 [toysrus.com] As the rods are moved apart or together, the contact with the large ball bearing moves up and down relative to the center of the ball. For a constant rotation speed, moving the contact points higher on the ball slows the linear speed of the ball. Oddly, I couldn't find a Wikipedia page on this toy, which must be interesting to physics modelers?
Ball bearing manufacturers already change the shape of the groove depending on the intended use of the bearing. For example, angular contact bearings are designed to take axial thrust in one direction, a common use is for the headset (steering) bearings on a bicycle.
Changing the groove shape *locally* could be a game changer for other reasons too, not just this one? I predict that there will be other uses for the ability to tune or adjust the ball rotation speed at different places around the bearing. For example, something might be done to reduce or change the vibration induced by the rate that the balls pass (when the balls act somewhat like the planets in a planetary gear reducer.)