We are continually amazed by the things people do with LEGO and Technics, especially those that require incredible engineering skill. There’s an entire community based around building Great Ball Contraptions, which are LEGO Rube Goldberg machines that move tiny basketballs and soccer balls from one place to another. Except for a few rules about the input and output, the GBC horizons are boundless.
Famed GBC creator [Akiyuki] recently built a GBC module that’s designed to show the movement of strain wave gear systems. These types of gear systems are used in industrial applications where precision is vital. Strain wave gears are capable of reducing gear ratios in a small footprint.
There are three parts to a strain wave gear: the wave generator, the flex spline, and the circular spline. [Akiyuki]’s wave generator is the elliptical gray disk in the center. It is attached to the input shaft. The flex spline is the piece around the gray disk that is transporting the little balls. It is called a flex spline because the wave generator forces it to flex into an ellipse. Industrial strain wave gears are of course made of metal, and the flex spline does not get quite as deformed by the wave generator as this one. The 1/8 reduction ratio also exaggerates the deformation.
We covered one of [Akiyuki]’s larger GBCs a few years ago. While that one is definitely impressive, this strain wave gearing module is quite the engineering marvel.
“The durability of the module has not yet been tested. It is envisaged that the durability of the module will be poor owing to the heavy load on the strain wave gearing.”
Shame, but it’s interesting to expose the public to mechanics like this.
Damn, I really miss my LEGO sets. Nice job, it looks like one of those ‘free energy’ attempts.
Man. When I was a kid I had a few technics kits and I thought I was amazing for making a zillion-to-one gear reduction box or something. This…. this is amazing.
Proper name is: harmonic gear.
Naw.
Look also at this new alternative to harmonic drive:
http://spectrum.ieee.org/automaton/robotics/robotics-hardware/sri-demonstrates-abacus-rotary-transmission
That’s a peice of work, would make a lot of money on eBay. Be many kids out there who would love that for xmas.
Anyway great job, just shows you can do anything which Lego if you put your mind to it.
By the way… It is just LEGO Technic, not Technics
Lego has now turned in to Marconi.
I imagine the company has done very well for themselves for what started as a children’s toy.
You know it’s a successful children’s toy when adults still play around with it and make discoveries.
$1000 worth of Legos.