The pinion pairs are 1 tooth different in size (40 and 41). I think If I were printing them I would print them as one piece instead of screwing them together. All three sets of pinions on the triple pinion design, would use the same angular offsets so all 3 pairs of pinion gears would be identical. All of the gears use the same module. As to the overall size it is 6" diameter and less than 2" tall. Other changes I would incorporate would be adding a ball bearing between the carrier shafts and the pinions.
I have no idea how much scaling down would affect the strength of it. Or even the overall strength of printed gear sets in general. So which tends to be stronger printed in plastic larger or smaller gear teeth. Also different numbers of teeth are possible and still work out to mesh correctly and can change the overall output ratio. I did a layout with 1.00 module gears 125/126 tooth rings and 50/51 tooth pinions and it all meshes the same and is the same overall dimensions as the version that John printed. This change increased the output ratio to 84:1. I'm very curious how strong this actually is and where the weak points might be. Todd Zuercher P. Graham Dunn Inc. 630 Henry Street Dalton, Ohio 44618 Phone: (330)828-2105ext. 2031 -----Original Message----- From: gene heskett <ghesk...@shentel.net> Sent: Thursday, December 16, 2021 3:48 PM To: Enhanced Machine Controller (EMC) <emc-users@lists.sourceforge.net> Subject: Re: [Emc-users] Harmonic Drive [EXTERNAL EMAIL] Be sure links are safe. On Thursday, December 16, 2021 1:10:30 PM EST John Dammeyer wrote: > A pencil line on both outer ring gears. The Blue 100 gear held tight. > Turn the Red Planetary cluster shaft and the Green 101 gear turns slowly. > > The assembly needs better mounting before backlash can be verified. > This design does look like it would be functional with a smaller 0.5 > module gear set with the ring gear holding at least 135T so that the > 'rack' cutter can be used. Largest set I have is 1.0module. > > I'm waiting for the Size 32 Chuck and collet set to connect onto my > brand name Harmonic Drive which is already connected as the 4th axis > for my LCNC system. It will be interesting to see if I can design a powered > tool to > hold the cutter for milling the ring gears. And maybe upgrade my pattern > for the Harmonic Drive to allow horizontal mounting. Something Andy > doesn't need because he's got the horizontal mill. > > Meanwhile, figure out how to mount this huge monstrosity. > > John Sweet John. Can you show us a pix from the blue side? And are the top and bottom pinions the same tooth count with the difference in the outer rings only? Thanks John. I am encouraged to see if I can make a smaller one when my printer is working again. > > > -----Original Message----- > > From: Todd Zuercher [mailto:to...@pgrahamdunn.com] > > Sent: December-16-21 8:19 AM > > To: Enhanced Machine Controller (EMC) > > Subject: Re: [Emc-users] Harmonic Drive > > > > DP is just the invers of module. > > > > 19tooth, 1.25module "should" be the right size sun gear for the > > 101/41 gear set, and 20tooth would be the one for the 100/40 set. > > But using them as ordinary planetary sets only gives a max gear > > ratio of about 37.9 to one running them compounded (6:1 * 6.316:1) > > Here is a nice site for playing with ordinary planetary gear sets. > > https://nam04.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww > > .thecatalystis.com%2Fgears%2F&data=04%7C01%7Ctoddz%40pgrahamdunn > > .com%7Ccf2a5ffcb0c744d46d1608d9c0d5999d%7C5758544c573f47cebee96c3e08 > > 06fb43%7C0%7C0%7C637752846476293126%7CUnknown%7CTWFpbGZsb3d8eyJWIjoi > > MC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&am > > p;sdata=jnRxmKvnfucjWz7k9Fl8oGZgKX2iDoMcug7I0SZ4zP0%3D&reserved= > > 0 > > > > However adding a sun gear to the input side of the original idea to > > turn the planet carrier instead of turning the carrier directly, > > might be a good idea (If you want huge gear reduction). That would > > add a 6:1 gear reduction multiplying the reduction significantly. > > (End result would be a whopping 404:1 gear reduction.) Holy crap > > that might just be getting a little out of hand. (How much > > reduction were we after in the beginning?) > > > > Here is a website that has the mathematical formulas for calculating > > a whole bunch of planetary gear arrangements. Including the two we > > are talking about here. The original idea is case#13 and this new > > one with the added sun gear input is case#15. > > https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fww > > w.engineersedge.com%2Fgears%2Fplanetary_epicyclic_gear_13736.htm& > > ;data=04%7C01%7Ctoddz%40pgrahamdunn.com%7Ccf2a5ffcb0c744d46d1608d9c0 > > d5999d%7C5758544c573f47cebee96c3e0806fb43%7C0%7C0%7C6377528464762931 > > 26%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBT > > iI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=AgDIT6T6W7LpgBRzSsaONGBPz > > fMl%2FsBDWdCxzDaHau4%3D&reserved=0 > > > > > > Todd Zuercher > > P. Graham Dunn Inc. > > 630 Henry Street > > Dalton, Ohio 44618 > > Phone: (330)828-2105ext. 2031 > > > > -----Original Message----- > > From: John Dammeyer <jo...@autoartisans.com> > > Sent: Thursday, December 16, 2021 2:54 AM > > To: 'Enhanced Machine Controller (EMC)' > > <emc-users@lists.sourceforge.net> > > Subject: Re: [Emc-users] Harmonic Drive > > > > [EXTERNAL EMAIL] Be sure links are safe. > > > > The AlibreCAM Gear generator doesn't accept module. Instead it > > wants number of teeth and pitch diameter. > > > > So I whipped up a spreadsheet that converts say the module 1.25 that > > Todd used and chose 19 teeth for the sun gear. That appears to be > > the right size pitch diameter for the test setup. At least when I > > check it out with my calipers. But of course 19T don't fit. It has > > to be 20T and that then physically doesn't fit. > > > > So creating a true planetary set with all the gears fitting appears > > to be a bit more difficult. > > > > John > > > > > -----Original Message----- > > > From: Gregg Eshelman via Emc-users > > > [mailto:emc-users@lists.sourceforge.net] > > > Sent: December-15-21 8:22 PM > > > To: Enhanced Machine Controller (EMC) > > > Cc: Gregg Eshelman > > > Subject: Re: [Emc-users] Harmonic Drive > > > > > > Does FreeCAD's gear wizard support both Diametral Pitch and Module > > > gears now?> > > > > On Wednesday, December 15, 2021, 04:36:00 PM MST, John > > > Dammeyer <jo...@autoartisans.com> wrote: > > > I still haven't been able to make a simple circle in FreeCAD. I > > > keep > > > > > > looking for the Alibre way of doing it which for my brain has > > > always been close to perfect. Never could use AutoCAD and I find> > > Fusion360 confusing . > > > > > However the gear tool is quite nice in FreeCAD. > > > > > > I'm still having some problem visualizing exactly how the gears > > > turn to create 67:1. So I thought I'd blow a bunch of money on > > > filament and print them. In hindsight I should have expanded the > > > pinion> > > holes to 22mm since that's a standard (cheap) bearing size. > > > > > Too late now. Just over 2 hours before the other 4 are done. I could > > > make some tubes that hold smaller diameter ones. Or just play with > > > the motion here first. See how it works and then decide if I want > > > to use my module 1.0mm cutters to make them out of metal. > > > > > > Or just print ones with inset relief to hold 8x22x7 standard bearings. > > > John > > > > > > > > > _______________________________________________ > > > Emc-users mailing list > > > Emc-users@lists.sourceforge.net > > > https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2F > > > list > > > s.sourceforge.net%2Flists%2Flistinfo%2Femc-users&data=04%7C01% > > > 7Cto > > > ddz%40pgrahamdunn.com%7Cf0e23e2e0c474d89921808d9c069626e%7C5758544 > > > c573 > > > f47cebee96c3e0806fb43%7C0%7C0%7C637752381126836342%7CUnknown%7CTWFpbGZ > > > sb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6M > > > n0%3 > > > D%7C3000&sdata=shhlXkCPj8ytCzxNUeNa5HZ3iPpEdTfuiLFMIzxvPhU%3D& > > > amp; > > > reserved=0 > > > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fli > > sts.sourceforge.net%2Flists%2Flistinfo%2Femc-users&data=04%7C01% > > 7Ctoddz%40pgrahamdunn.com%7Ccf2a5ffcb0c744d46d1608d9c0d5999d%7C57585 > > 44c573f47cebee96c3e0806fb43%7C0%7C0%7C637752846476293126%7CUnknown%7 > > CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJ > > XVCI6Mn0%3D%7C3000&sdata=PNhxzJYrLE%2BSJTRRBtqxVnxfx%2FmumnFxmPW > > TstHlCdk%3D&reserved=0 Cheers, Gene Heskett. -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. 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