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I can't be that lucky..

A project log for MPRT - Modified planetary robotics transmission

The reduction of strain-wave, but using a 'single' stage planetary gearset.

daren-schwenkeDaren Schwenke 05/09/2019 at 20:432 Comments

For kicks I decided to add an idler gear. This is one way to prevent the output ring from pushing in on the planets. 

Either I'm incredibly lucky, or there must be something happening with the math here that I don't understand that makes this work.

It fits perfectly.  The idler as shown here is the gray transparent one.

I just used the output pitch, and added 3 teeth to the sun.

It's gotta be the math, but I had no idea it would be that easy.  I'll be using that.

I will need to adjust the model to have more squat gears though so I still have room for 2 6mm tall bearings on my motor shaft.  Working on it.

<EDIT> I also just realized how to solve for the actual output pitch required here.  Yay!</EDIT>

Discussions

Florian Festi wrote 05/09/2019 at 21:03 point

It is not that surprising: teeth_ringgear = teeth_sungear +  2 * teeth_planets. So unless you are using some fractions for the number of teeth anywhere...

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Daren Schwenke wrote 05/09/2019 at 21:25 point

Yep.  It would seem that way.  I just thought it would be harder for some reason.

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