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As soon as SRI explained how their new Abacus transmission worked, we were absolutely sure that it was cool enough to share. In a nutshell, here's why: It's the first new rotary transmission design since Harmonic Drive introduced its revolutionary gear system in the 1960s*, and it might give harmonic gears a literal run for their money.
Harmonic gears are great, but they're also super duper expensive, because they require all kinds of precision machining. Alexander Kernbaum, a senior research engineer at SRI International, has come up with an entirely new rotary transmission called the Abacus drive, and it's a beautiful piece of clever engineering that offers all kinds of substantial advantages:
The Abacus drive (named because it has components that look like the beads of an abacus) is what's called a pure rolling transmission: there are no parts that rub or slide against each other (like gear teeth), only parts rolling against other parts. Rubbing and sliding result in wasted energy, and in fact, conventional transmissions are typically only 50 percent efficient. Kernbaum says that Abacus has an efficiency "in the high 90s," a massive improvement.
[Video]: SRI Abacus Rotary Transmission [Javascript required]
* Harmonic drive gears are based on an ingenious mechanism known as a strain wave gear, which was invented in 1955 by a prolific engineer named C. Walton Musser (his other numerous inventions include the recoilless rifle and the ejection seat).
(Score: 5, Interesting) by physicsmajor on Thursday October 20 2016, @08:45PM
So... a couple things.
First: this was just announced. Not available yet. Hard to wield the slashvisemnt card in that context.
Second: I assume you aren't familiar with this entire field. And likely didn't read or watch the video. Rotary transmissions - which are basically an inline widget to downconvert a higher RPM to a lower one - are hugely important anywhere servos/motors are in use. This isn't a new transmission for your car, it's to improve what we can do with robotics and mechanical engineering. Where they aren't, the main reason is usually cost. Which brings me to...
Third: Have you SEEN the Harmonic Drive? That's the current state of the art, and it's bonkers more complicated and way harder to manufacture than this.
It's no IndieGoGo CGI hype video either, they've got a bunch of actual demos undergoing actual testing. I've played the armchair skeptic plenty enough, and sometimes it is appropriate. From what I'm seeing here, this isn't one of those times.
(Score: 1, Interesting) by Anonymous Coward on Friday October 21 2016, @02:11AM
Why are we calling these things transmissions? They don't switch gears.
The proper term is "reduction gear", or perhaps "reduction roller" for this one.
(Score: 3, Informative) by frojack on Friday October 21 2016, @05:17AM
Variable ratio reduction gear. Tapered roller thingies do that.
No, you are mistaken. I've always had this sig.
(Score: 2) by ledow on Friday October 21 2016, @03:56AM
1) Doesn't matter. It's a commercial pre-order, if you want to be fussy.
2) I watched and read. Their previous thing is on a Mars Rover. It's a limited-scope, fixed gearing reduction that seems to use or specialise in extremely high ratios in compact spaces (basically relying on the natural motion / sliding wobble of a metal band tied around the moving gears to form the outer "gear"). Specialist stuff exists and is boring precisely because it's limited in its scope to specialist uses. I'm sure I can find an ultra-efficient motor if I spend millions of pounds, it doesn't make it interesting - same kind of thing.
3) Yeah, I saw it. It looks fancy. This thing looks fancy. Like ultra-precision-milled double-conical bobbins running in a matching cut-out around the periphery of the gearing that - one slip - and the whole thing falls apart or jams. That kind of stuff is "pretty" but also so far into the "it costs money to get it THIS right" category that it's not interesting again.
"Actual demos"in "actual testing" just means a prototype to me.
It's a cool-looking, impractical, rare-use, specialist prototype that doesn't have a way to extend it to generic use such that you'll EVER see one in real-life. There's plenty of that kind of thing about. Like most of the stuff on the Mars rover.