For the belt idea, it might work better to invert the whole thing, So you have the belt teeth in and one gear with two fewer teeth than the belt, then the follower wheels on the outside of the belt compressing it to mesh with the smaller gear. The hardest part might be finding a belt wide enough to reliably flex between the two gear diameters. (Something tells me this sounds better than it can actually work in practice.) Todd Zuercher P. Graham Dunn Inc. 630 Henry Street Dalton, Ohio 44618 Phone: (330)828-2105ext. 2031
-----Original Message----- From: Sam Sokolik <[email protected]> Sent: Tuesday, January 26, 2021 2:41 PM To: Enhanced Machine Controller (EMC) <[email protected]> Subject: Re: [Emc-users] Maybe a minimally printed harmonic drive? plus - you fold one inside out - the pitch doesn't match up very well. On Tue, Jan 26, 2021 at 1:30 PM Gene Heskett <[email protected]> wrote: > On Tuesday 26 January 2021 13:04:11 Chris Albertson wrote: > > > The weak link on all 3D printed harmonic drives is the flex cup. The > > plastic fails after some hours of use. The best design I've seen to > > overcome this is to NOT print the flex cup. They used a wide double > > side timing belt for the inner teeth. > > > > The thing that very few You tubers do when designing 3D printed > > machines is to not simply copy the design of metal parts but start > > the design from the ground up knowing they will be using plastic. > > Plastic has very different strength and stiffness to volume ratios. > > So if your part looks like the metal equivalent it is a good clue > > you are doing "eyeball engineering" and your experience with metal > > is influencing your design. > > > > If you need to print a reduction gear and need a really big ratio > > the Cycloidic reduction system really does work better especially if > > the rolling parts are sealed bearing units that are press-fit into > > the plastic. > > > > That said, I've printed parts in plastic to directly replace metal > > or even rubber and I just have to accept the very short lifetime and > > low strength. Plastic is a good material to verify ideas quickly. > > > > In any case, use a timing belt for the flex wall and it might last > > 30 years. > > > But that brings up the tooth profile problem. I've not seen a timing > belt that resembles the triangular splines? > > > On Mon, Jan 25, 2021 at 8:47 PM Sam Sokolik <[email protected]> wrote: > > > I am sure the torque is limited - but I feel it might have > > > possibility... > > > > > > https://www.youtube.com/watch?v=QlpkmEEhFqc > > > > > > _______________________________________________ > > > Emc-users mailing list > > > [email protected] > > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > 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 > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
