On Saturday 16 May 2020 15:09:08 Chris Albertson wrote: > One interesting and fun option is to make your own cycloidical > reduction. These are completely buildable on a CNC mill that can do 2 > 1/2 D machining on mild steel. Unlike most other gears, these can be > cut from plate stock with just an end mill. THey can be 3D printed > too. > > See the wiki link below. In a real system, the purple and grey parts > are made from sealed bearing units and you'd have two moving plates > stacked 180 degrees out of phase so as to counterbalance each other. > But the good points are (1) high torque, (2) very low backlash, (3) > compact size, (4) very simple 2D geometry > https://en.wikipedia.org/wiki/Cycloidal_drive > There are 100 Youtube videos about people making these with 3D > printers but they work better with metal. These have become popular > with people building robot arms and robot legs but could also be > driven with a servo motor and used as a rotational axis for a machine > tool. > > In a machine tool application, you would place a rotational sensor on > the axis and close the servo loop inside the controller. A cycloidal > system can be back-driven (just like spur gears or timing belts) so > they MUST be used in a closed-loop
Which then brings up the need for some math. So how would one go about getting from a 3 phase stepper motors holding power, say 3 NM to lbs/ft at the output of a 12/1 cycloidal gear? Assuming zero losses in the bearings, which I'd guess at 5% if decent bearings. Could that 3NM motor hold it, or even move it under cutting loads? > > Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/gene> _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
