Nema 17 Stepper Cycloidal Drive Gearbox 12:1

Disclaimer: This is a 3D-printed gearbox in the development phase! It won't withstand the same torque nor accuracy as a machined metal equivalent. This required some additional parts and depending on the application additional modelling to suit your application. Make sure your Nema 17 has a 5mm d-shape output shaft or design your own adapter. Output is 12:1 ie output is spinning 12 times slower than the Nema17.

 

With that said here is my take on a small cost effective Cycloidal Drive for Nema 17s. This has been developed over several month and a lot of work went into making this.

Boost MeTherefore I would really appreciate a boost to make all the work worth while. Thanks a lot!

 

There are a couple different tolerance sizes available depending on your material and printer (just a matter of trying them out; file name: NM17.03.004 Cycloidal Drive - Gear Wheel). You are looking for a very snug but not impossible to turn fit if that makes sense. Keep in mind it will wear a bit after printing and get a bit looser.
 

The NM17.11.001 Cycloidal Drive - Mounting Bracket Spacer is a spacer to test the design. The intention is that you replace it with whatever mounting bracket you need for your application (5mm space).

The encoder bracket on the back of the motor is optional (designed for AS5600). You do not need it for the gearbox.

 

Assembly Instructions:

Assembly as seen in photos. The M2 screws need to be screwed into the gear wheel (important as that is what gives the strength in the part). The 6706 bearing needs to be pushed over the Output Bracket and the 685 bearing goes inside. Make sure to assemble in the correct order (a bit finicky at first). I tried my best to show many photos and an explosive view. Make sure to grease the gear and housing to reduce friction and increase lifespan! I used PLA basic and PETG interchangeably. Ideally, something that is strong with a smooth surface finish (ie try to avoid matte and fibre-infused materials).

 

Parts list:

Bearings:
- 1x 6706 30x37x4mm Bearing

- 1x 6700 10x15x4mm Bearing

- 1x 685 5x11x5mm Bearing
 

Fasteners:

- 4x M3x22 Capscrews (I had to shorten some longer ones I had)

- 6x M2x12 Countersunk (recommend not slotted as its a pain to screw in, just what I had)

- 6x M3x4.2x3 (or similar length) Threaded Inserts

- 6x M3x6 Capscrews (for mounting to the output bracket; you may vary depending on what you mount)

 

Misc:
- 1x Silicone Grease (or what you prefer)

 

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