Japanese company Coo Space says it has devised a way to space the balls in a ball bearing without a cage. Such cages are used to keep the balls separately and evenly spaced between their inner and outer bearing races.

The Autonomous Decentralized Bearing (ADB) puts a small indentation, or groove, into the outer bearing race. As the balls slide over this groove, they slow down slightly before speeding back up. The company says this does nothing to affect the bearing's regular performance. However, if two balls touch each other as they cross over the groove, the first ball's deceleration causes the second ball to brake. This, in turn, separates the two as they go around the races.

Without the need for a cage, the bearings can be run unlubricated. Coo Space claims that the ADB experiences as little as 10% of the friction of a regular ball bearing.