Cycloidal drives have an entrancing movement, in addition to a number of different benefits – excessive torque and effectivity, low backlash, and compactness amongst them. Nonetheless, a lot as [Sergei Mishin] likes them, it may be tough to 3D-print high-torque drives, and it’s typically inconvenient to have the enter and output shafts in-line. When, due to this fact, he got here throughout a video of an industrial three-ring lowering drive, which works on the same precept, he naturally designed his personal 3D-printable drive.
The primary challenge with 3D-printing a traditional cycloidal drive is with the eccentrically-mounted cycloidal plate, for the reason that pins which run by means of its holes want bearings to maintain them from shortly carrying out the plastic plate at excessive torque. This places some unlucky constraints on the scale of the drive. A 3-ring drive additionally makes use of an eccentric drive shaft to trigger cycloidal plates to oscillate round a set of pins, however the enter and output shafts are offset in order that the plates embody each the pins and the eccentric driveshaft. This simplifies building considerably, and likewise makes it attainable so as to add multiple enter or output shaft.
Because the title signifies, these drives use three plates 120 levels out of part with one another; [Sergei] tried a design with solely two plates 180 levels out of part, however since there was a degree at which the plates might rotate simply as simply in both path, it jammed simply. Not like customary cycloidal gears, these plates use epicycloidal reasonably than hypocycloidal profiles, since they transfer across the exterior of the pins. [Sergei] helpfully wrote a Python script that may generate profiles, animate them, and export to DXF. The ultimate efficiency of those drives will rely upon their design parameters and printing materials, however [Sergei] examined a 20:1 drive and reached a decent 9.8 Newton-meters earlier than it began skipping.
Even with out this design’s benefits, it’s nonetheless attainable to 3D-print a cycloidal drive, its cousin the harmonic drive, or much more unique drive configurations.
