"The first working version of a years-long project to create a Continuously Variable Transmission design that can be 3d printed and used as a desk model or possibly in an RC vehicle. I also have the notion that eventually I could 3d print a tranmission that could be usedul to build something larger like an electric bike or scooter. Currently I am about 3 years into the design process, with about 15 different itterations of the mechanism. This version was deemed unworkable due to the complexity of the design, lack of compactness, inability to handle higher torque loads, and it was basically more of a prototype design concept than anything else.

This version has not been mathematically profiled and I don't know off-hand what kind of shift forces or gear ratios are happening, but geometrically it should actually work without load, in theory. The latest version, still in development, has been completely profiled and has a gear ratio from 10:1 to 1:10, even with a relatively small transfer wheel angle range!

Over time, the CVT went from this open half-toroidal cavity type design with 2 transfer "wheels" to an enclosed, full-toroid design with 4 transfer wheels and limited slip capabilities. Unfortunately it also blew up to nearly 100 moving parts, using gears and linkages to adjust and hold all 4 transfer/shift wheel elements while keeping their angles consistent with one another. On a 3d printed model, this simply would not do except for a desk toy curiosity.

The current design cuts the number of moving parts down to less than 20 and uses a voice coil to adjust the shift angle of the inner transfer wheels, though this version still only exists on paper. Hopefully a fully operational 3d printed physical model will be realized relatively soon!


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