Small progress report on Todd's version of the harmonic drive. I added a back mount that holds a 19x40x12 bearing. A cap to hold the bearing in place. Then a new drive arm sized to 19mm and a 19x1.25mm thread along with a nut. The end of the drive shaft has an 8mm hole for the stepper motors that arrived last week. Will likely require a metal collar around that part with threaded holes to clamp the flats on the motor shaft. The plastic just isn't strong enough to hold these types of threads.
http://www.autoartisans.com/harmonicdrive/BearingDriveShaft-1.jpg http://www.autoartisans.com/harmonicdrive/BearingDriveShaft-2.jpg http://www.autoartisans.com/harmonicdrive/BearingDriveShaft-3.jpg Now to contain the green output gear. Here's one idea. I have a bag of 5.5mm steel balls meant for keeping model paint mixed. With 80 of them held in place by the bearing spacer (which I would probably make out of metal for this project) it should theoretically capture the gear and reference it to the mounted frame. A dual row of balls might be better. http://www.autoartisans.com/harmonicdrive/BearingPath.jpg http://www.autoartisans.com/harmonicdrive/BearingSpacer.jpg http://www.autoartisans.com/harmonicdrive/MountFrame.jpg Commercial units look like they use rollers set at angles but even a 32mm one from aliexpress is over $200. Probably the next best step to create something like this is to down size it to brass or steel gears small enough to fit into a much lower cost set of bearings. The key with this system will be the bearings. Anyway, other than printing a conversion base for motor to bearing assembly I'm not sure this warrants further work unless I can come up with an inexpensive method to contain the front gear. Suggestions, as always are welcome. John _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
