this deserves more views this is incredible

I like the version with fixed gears on the wheels, in a bigger version, maybe the gears could spin with the change in wheel size to still be engaged with the belt but allow the gears to roll along the gear whilst the wheels change size if that makes sense

isn't CVT what's used in snowmobiles?

Great concept and execution, the automatic version is especially clever. My only concern is that, since the clips necessarily grab the chain in discrete intervals, this transmission does not appear to truly be continuously variable. Unfortunately a truly continuously variable transmission that does not rely on a friction drive (belt drive, pivoting rollers) is a bit of an unsolved problem in mechanical engineering.

Amazing concept, the variable size wheels are genius by themselves.

A massive improvement on your previous CVT design, and I also can't wait to see this in a car.

The expanding section reminds me of my toy truck from the 80's "The Animal" watch?v=Afofc_Jt86s

The expanding section reminds me of my toy truck from the 80's "The Animal" kzbin.info/www/bejne/d5fSl5aVf9lrbNU

hallelujah, the rial CVT works EXACTLY like that ( 10:25 )

One thing I always wonder when I see a Lego transmission where friction or tension are used to gauge output resistance: is the torque gain from changing ratios greater than the overall power loss from the friction/tension in the resistance measurement? And if so, by how much? Genuinely don’t know. I’m as far from an engineer you can get, but I love Lego technic. Regardless of how efficient this design ultimately is, it’s incredibly clever and undeniably solves the belt slip issue with the classic cone style CVT. Great work on the variable size wheel design, it’s brilliant!

One idea for a car it to try to put 2 of these in series giving more torque and greater spead ranges! Excellent work!

You should try building a lego car that uses this CVT to really show off the capabilities of this machine

This is so cool!

As soon as I saw the new system I immediately remembered Veer Shift Drive. It's very similar)

Lego now offers the slip gear, white boxy gears with a light grey axle collar in the center. These are useful for bypassing systems of extreme torque backlash, like, say, when the escapement is stuck for a second because that’s how it works. Because they escapement works by creating a brief moment of very high torque then releasing said torque, using a slip gear as an input point and a solid gear as the connection between the two, you can use a motor to power a chain which could be an infinite escapement force that never needs wound.

there is a cvt type like this although usually it uses a rubber belt, one side has fixed diameter and the other uses wheels on the end, it also uses hydraulic/pneumatics for expansion. your design is very cool with counter changing diameters for drive and driven giving a wider gear ratio change, although due to the size of lego pieces, this is slightly limited and is probably very hard to make smaller for lego cars. it will be cool to see that comes of this design in the future

about why the wider rubberband didnt improve as much as hoped: the formula to describe friction does not include the area of contact but instead the friction force f is calculated by multiplying the normal force N with the friction coefficiant μ between the two surfaces: f = N * μ this does not include the area of contact

This is such a beautiful mechanism

The Schmitt linkage (or however its spelled / named sorry memory bad) made me so excited cause I've watched so many "simple mechanisms" / "simple machines" in Lego videos and they always demonstrate the concept, but never show an application of it (which, to be fair, isn't the point on those videos) and I'm just so excited to finally see someone using them practically!

Better then a Nissan CVT

This channel is soo under-rated!!!

I think a lot of the problem is not the lack of friction but the stretch of the rubber bands. If you had a belt that had something to keep it contracted it would work far better as the side load of the torque transfer tightens the belt and makes it tensioned against the variable cones.

If you were willing to sacrifice the cones to live forever for a CVT, you could dip them in liquid rubber. Rubber on rubber is friction city. I think the auto CVT would need to live within a specific RPM range or the centrifugal forces will counter those bands.

I'm amazed at the simplicity of the chain drive automation, but as it stands the gear ratio is currently quite small. I'd be very interested to see a follow-up video that puts two of these stages in series, to see if you can automatically cover a much larger range of reduction speeds.

Whoa. Expandable dorito. Braaaaap! Rotary owners be like….. Very cool. Good job

This is better than what's in my hyundai

This man just solved the CVT problem in automobiles…

The wider belt didn’t do anything because contact area has nothing to do with friction

I seriously expected this channel to be at around a million subscribers like the other technic channels. But this lad is better for giving voiceovers. Keep it up!

idc about the legos his voices is so calming

next: use CVT & differential. make the output spin 0rpm in gear & the engine is runnning

That is such a cool invention! I think if this was made out of metal with many more circle segments it could actually viable for a car

Dud, you are so smart it is scary.

Watching these makes me feel the same as watching a Ben Eater video

Very elegant device

The automatic CVT blew my mind

Love the videos So much better with you talking

what's the flutter like on the output gear? given the gearing is effectively triangular won't the output speed vary over the course of a rotation, doubly so with the continuously variable design and having inconsistent alignment?

This is really cool! I love the design of the wheels with the variable diameter : )

Love the videos man!

in a realistic application you probably want it to always to default to the shorter ratio, that way you aren't stalling your input instantly, I know the belt drive CVTs for small displacement engines work like that, using centrifugal force to actuate them

thats so cool!! you make the mechanics seem so approachable and you explain stuff really well. great builds :)

You are so clever. Indeed the best lego transmisión i have ever seen

This is a solid build, probably the most impressive lego transmission I've seen!

I've seen a number of Lego CVTs/automatic transmissions and this is the first time I've seen someone use variable diameter wheels. I suppose there will be some irregularities in the output speed, similar to what you get with a universal joint. I'm definitely interested to see if it works in practice in a vehicle or something. It would be interesting to see if it will go to the highest mechanical advantage on acceleration from a stop of a heavier vehicle.

underrated af!

I wish I could whach this but I have homework 😢

Hi

First (sorry couldn't resist)

20:31 - 20:41,Didn't get it, pls explain.