Compact Harmonic Drive

thingiverse

This is a very compact harmonic drive. The harmonic drive itself has a reduction ratio of 65:2 and the added pulleys (depending on the size) can make it vary from ~80 to ~250:1. I recommend using the 65T pulley and getting it SLS printed in nylon from a place like Shapeways because it is always under load and needs to be fairly accurate. The strain wave generator has 3 different diameter sets depending on printing accuracy (I use the middle on or the one with two dots). There are two types of harmonic drive (STL and Fusion360 files), one only has 2 contact bearings but has adjustable tolerances, the other has a full set of 8 contact bearings but the tolerances must be modified in Fusion360. I used the one with two contact bearings to find my tolerances and then used that to make the full oval have the right tolerances. I will not provide support or help for this buy you can look through the F3D files which will answer most questions. Assembly and Testing: https://www.youtube.com/watch?v=aDlfOQVmfpk&t=1212s