The Inception Drive, just invented by SRI International, is an extremely compact, infinitely variable transmission developed for robotics, but which could have all sorts of other applications. You have to watch the video and think about it for a while to see what's going on and even then, you'll have to think a little more to picture it in your mind. When you watch the video, keep your eyes on the shafts in the center to see the output slow and change direction.
The point to remember is that it has no clutch and the input, an electric motor in the case of robotics, is always turning at a constant speed in one direction, but by varying the size of the pulleys, you get not only a variable transmission in one direction, but it can come to a complete stop and then reverse direction of the output without any change in speed or direction of the input! It's called an IVT or infinitely variable transmission instead of a CVT because it has a zero point, it can stop the output entirely within the transmission, no clutch necessary and then smoothly go in the other direction.
There are a few very important things going on here that are very hard to see, because they’re happening inside the drive itself. The first thing is how the two pulleys interact with each other. This happens through the V-belt, of course, but it’s not as though one pulley turns, which turns the belt, which causes the other pulley to turn, as in a conventional transmission. Rather, the outer pulley is fixed and doesn’t turn at all, while the inner pulley, which is nested inside the drive, has a wobble in it, since it’s mounted off-center to the input shaft.
It's still brand new so there are a lot of things to work out, but It's amazing to see what they've done here, the size and weight savings alone will get your attention, but I can't help but keep going back to how it actually works. I love it!
Source: Spectrum
JP Kalishek says
They certainly need to broaden their focus for uses of that excellent device.
Tons of automotive and manufacturing, uses immediately come to mind
Paul Crowe says
That’s one of those situations where the inventors are so focused on one application they never mention anything else, though I have to believe they’re not unaware of how widely applicable this is.
WillyP says
I don’t think the issue is that they don’t see the possible applications, but that they know in order to scale this up to the horsepower and speed requirements of a motorcycle, it would be very large and out of balance. That’s not to say those issues couldn’t be overcome, but that they are in an early stage of development.
Paul Crowe says
Well, since this is basically a “proof of concept” prototype, there’s no telling how far this can or can’t go. Will it even be practical in low power situations, let alone, high power and torque environments? No one knows yet, but now that they have demonstrated the idea works, they can focus on reliability, scale and everything else. It’s already amazing, I’m hoping this can be refined and put into some actual working environment. For a motorcycle, car or anything else? You’re right, that’s probably a long way down the road.
Rod Newstrom says
I’m developing a new rotating cylinder opposed-piston supercharged radial HCCI engine. It will yield 76 HP at 5252 RPM in a disk shaped engine of under 12″ diameter and 6″ depth (including everything but the fuel tank). This will be connected through a clutch to a motor/generator of similar diameter adding only 3″ of depth. A compact transmission such as this would faciliate an engine-per-wheel distributed hybrid power architecture. Hopefully they’ll have a real one by the time my engine is ready for testing. Thanks for pointing it out Paul!
Dokter says
Rod, great undertaking.
Keep us updated on the engine progress. What are your combustion chamber specs? Compression ratio? Spark-assisted? Fuel operability?
Cheers!
Viv says
Looks like its based on a Harmonic drive (just google it)