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

Wobble Ring Stepping Motor V2!!

by Ndrew, published

Wobble Ring Stepping Motor V2!! by Ndrew Feb 20, 2013


This is a snap together version (some glue) of my printable motor. It has been shrunk and uses only 9 pieces, air pistons included.

The bellowPiston part is printed with no infill and needs to be airtight. When inflated it extends outward to push the glued on bellowLink part. The bellowLinks then push the wobbleRing, meshing with the drivenGear. Each piston is inflated and deflated sequentially to "step" the motor 4 degrees forward or backwards.

This thing is the successor to this:

And uses sgcg's fastener library

Also uses mechadense's epi-hypocycloids from:

The bellows used are modeled after this general shape:

Though I hope this latest version shows much improvement, I realize there is always room for better design. Please, chime in if you see room for improvement.

I also have to mention that I have not printed this yet, so I don't know if it will work. Of biggest concern are the bellowPiston parts, because they need to extend at least 2mm to be productive. I also don't know how easy it will be print 45 degree overhangs that are airtight AND slightly flexible.

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I started to wonder :P
Right now I'm working on a gcode converter to polar coordinates for another project but after that I'm going to make a solenoid version that's parametric. That way anyone could test it.

... Sorry, tried replying earlier but clearly my comment didn't save :/

Turns out I gave the solenoids to a friend for another project, but I may be able to get some of them back... If not I'll look at reprapping solenoids for this motor.

Iomega external drives... I should be able to dig up the details for you tonight or tomorrow

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All parts are oriented for printing without support.

Print 1 each of the following:

Print 3 of both the bellowPiston.stl part (without infill) and the bellowLink.stl part.

Open the bellowPiston parts at the top end by taking off the last layer.

Glue together the bellowPistons and bellowLinks.

All pieces snap together downward from were they are seen in the exploded view.

The wrsmAssembled.stl file shows the completed thing, minus gluing.


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Anonymous on Feb 20, 2013 said:

Thanks! Just wish I could test the darn thing :P

AphoticJezter on Feb 20, 2013 said:

Awesome project!

Ndrew on Feb 20, 2013 said:

Thanks! Just wish I could test the darn thing :P heh