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. http://www.thecatalystis.com/gears/
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://www.engineersedge.com/gears/planetary_epicyclic_gear_13736.htm 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%2Flist > s.sourceforge.net%2Flists%2Flistinfo%2Femc-users&data=04%7C01%7Cto > ddz%40pgrahamdunn.com%7Cf0e23e2e0c474d89921808d9c069626e%7C5758544c573 > f47cebee96c3e0806fb43%7C0%7C0%7C637752381126836342%7CUnknown%7CTWFpbGZ > sb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3 > D%7C3000&sdata=shhlXkCPj8ytCzxNUeNa5HZ3iPpEdTfuiLFMIzxvPhU%3D& > reserved=0 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
