Compact 44:1 Harmonic Drive

44:1 Compact Harmonic Drive

I wanted to build a Harmonic Drive gearbox that was as small as possible and had the highest possible gear ratio, and that's what came out of it. Another goal was to design a flexspline that works almost stress-free. Here, the Flexspline was loosely inserted into a toothing that is connected to the housing with no play and torsion-proof.
The circular spline (output shaft) is held stable in ball bearings, so it does not deform under load. Last but not least, the direction of rotation is the same as that of the motor.



BOM:

2x Bearing 6810 2RS https://amzn.eu/d/19QKWSp
2x Bearing 606 ZZ https://amzn.eu/d/fdh3d0U
1x NEMA17 Motor with 5mm D-Cut shaft
4x M3x6 allen screws (for motor mounting)
2x M3x8 allen screws (for wavegenerator)
2x M3 hex nut
8x M3 Heatset inserts (optional)
Grease

Printsettings:

Flexspline: 0.25mm nozzle, layerheight 0.12mm, PETG
Flexspline_Outer_Ring: 0.25mm nozzle, layerhei