May 18, 2015
Greaseless bearings that eliminate sliding friction
Coo Space has developed revolutionary bearings that eliminate sliding friction.
Bearings are components used to reduce friction so objects can rotate more smoothly. Bearings have a long history; their principle is even illustrated in ancient Egyptian paintings. As bearings are essential for making machinery run consistently, they’re widely used in familiar items such as cars and electrical appliances.
"Bearings have balls that roll between an inner ring and an outer ring. There are retainers to stop the balls sticking to each other. Leonardo da Vinci designed bearings like this 500 years ago, and the design hasn’t changed since then. The problem with bearings is that sliding occurs between the retainers and the balls, so grease has been essential. But the ADB, or autonomous decentralized bearing, that we’ve developed doesn’t need retainers."
In bearings, retainers have been essential, to prevent contact between balls. But Coo Space has succeeded in separating the balls without using retainers, by making indentations in the outer ring where the balls touch it.
"Ordinary bearing balls roll while in contact with the ring directly underneath. If you make holes in the part directly underneath, so the balls roll while making contact horizontally, the amount of forward motion per revolution is less. That makes the balls slow down, and then speed up, so behind an accelerated ball, there’s always a gap. That’s the principle here: The balls are separated by slowing them down and speeding them up very slightly."
By separating the balls, friction can be reduced by up to a factor of ten. This method is also expected to alleviate early failure due to inadequate lubrication or low attachment precision. In addition to a standard product, Coo Space has started to provide samples of specific bearings.
"Outside Japan, a big steelmaker is interested in these products, so we’ve concluded a technology transfer agreement with one of its subsidiaries. We’ve also had other inquiries from overseas, and we can supply prototypes, so we’d like to expand this business."
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