A Japanese company figured out how to cut a lot of friction from a ball bearing.
From Gizmag:
Greaseless ball bearings: A revolutionary spin on a design that's been around for ages
While the ball bearing might be among Leonardo Da Vinci's less celebrated inventions, it's arguably one of his most important. Though it was initially designed as part of his failed helicopter invention, it has stood the test of time – there are ball bearings of a similar design to Leonardo's in just about every moving machine.
The basic design in simple: in order to reduce rotating friction between two pieces, the bearing has an inner and an outer race. A number of balls roll in between these two races, allowing the smallest possible contact points between the inner and outer races. The balls roll a lot easier than the two pieces would slide against each other.
The ball bearing can only work if the balls are kept separated and evenly spaced throughout the races. Touching each other would produce friction, and uneven spacing would cause the bearing to be weak under loads from a certain direction. So most bearings use cages to separate and evenly space the balls.
These cages cause friction and to reduce this friction, you generally need to lubricate your bearings, often with thick grease to ensure a long lifespan.
All of which is a long way of getting around to this: Japanese company Coo Space has come up with a way to reliably space the balls out without needing a cage.
Big difference and all they did was machine a small depression in part of the outside groove - it slows that one ball down a little bit so they do not bunch up.
More at the site including a couple videos - fascinating technology. The website for the company is here: Coo Space.
