MakerBot Print is our newest print-prepration software, which supports native CAD files and STL assemblies,
allows you to interact with all your printers via the Cloud, and many other exciting new features.

Download Now

Hey! This thing is still a Work in Progress. Files, instructions, and other stuff might change!

FTC Tetrix / AndyMark Motor 9:1 Gearbox, Hypocycloidal single stage - V4

by cheer4ftc Nov 18, 2014
Download All Files

Thing Apps Enabled

Please Login to Comment

great job! Can this structure be accelerated in reverse?

I don't think so. Turning the "output shaft" part will result in a lot of forces that are not in the direction of rotation.

Also, usually "raw" DC motors are very fast and most motors have output gearboxes to slow them down. So if you want them faster, just remove the output gearbox. For example, AndyMark sells the motors with no gearbox (fast and weak), a 3.7:1 gearbox, a 20:1 gearbox, a 40:1 gearbox, and a 60:1 gearbox (slowest and strongest). The version with no gearbox is quite fast (e.g., it can run a small fan and create a breeze).

Thank you, but I actually want to see if I can do it with human or wind power^_^

A straightforward cascaded spur gear design would work to either slow down or speed up, like this one: https://www.thingiverse.com/thing:507641

Note that 3d printed parts may not be ideal at either super-high torque or at super-high speeds.

FTC Tetrix / AndyMark Motor 6:1 Gearbox - V7

Thank you very much, but I know that gear box only two teeth involved in the transmission, and movable teeth gear can have 50%, so would like to try , such as this video

Nice! An advancement in the Hypocycloid gear box state-of-the-art.

How did you generate the hypocycloidal profile you used? Do you have any problem keeping the motor shaft anchored to the eccentric piece so it spins the gear?

Since I was using OpenSCAD, I wanted my profile to be entirely constructed by adding and subtracting cylinders. Given the radius of the elements and the number of "bumps", I derived the radii of the additive and subtractive cylinders so that they'd be continuous and with a continuous derivative (slope) at the intersections. The equations for the radii are in the .scad file.

For the rotating cam, I was experimenting with a few other shapes (like in your other example project) which made me only put the additive cylindrical bumps on. Given the final result, I probably could have reverted to the additive/subtractive sinusoidal-like shape that the outer mountBottom has.

The ring and hub holder is just the shapes of the bump additive circles with the larger radius to account for the cycloidal rotation.

So far, the motor shaft has worked fine in the eccentric piece, but I haven't put the output under a lot of load yet (or stalled it). No doubt something will break if it's under a lot of load. :)

Thanks for your comment!