It is a Freecad file, you have to open it with Freecad. (If I double click on it in a file manager on a Linux pc I get that list to.)
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: Tuesday, December 14, 2021 1:53 PM To: emc-users@lists.sourceforge.net Subject: Re: [Emc-users] Harmonic Drive [EXTERNAL EMAIL] Be sure links are safe. On Tue, 14 Dec, 2021 at 1:07 PM, Todd Zuercher <to...@pgrahamdunn.com> wrote: To: enhanced machine controller (emc) The "pinned" pinions are for if they are to be conventionally made metal gears to accommodate easy conventional manufacturing. If they were printed, they could simply printed as one piece. A metal set of gears would have be hobbed separately, then stacked and offset at the correct angles then drilled and pinned together so they turn as one gear. Playing with the cad some more I'm not even sure that it would even be necessary to fudge the modulus on the ring gears to make them both the same diameter. But it comes at the cost of getting the highest possible gear reduction. It is only 1.5 tooth/rev instead of 1 tooth, but it is still better than the 2 tooth/rev max possible with the true harmonic drives. (Although a true harmonic drive can get away with and probably works better with finer/smaller teeth.) For example if the fixed ring gear has 100 teeth, meshing with 3 pinions of 40 teeth on the driven spider. (see attached pic) Then on the output side adding one tooth to the ring gear(101) and pinions(41) The teeth still mesh perfectly at the same spider axel lengths. Then pin the 40 and 41 tooth pinions together. I think the final drive ratio would be 67-1/3:1. One revolution of the spider would turn the pinions 2.5 times, and advance the driven ring gear 1.5 teeth. (please correct me if I'm wrong in my calculations.) Also I think making the output ring and pinions one tooth smaller instead of larger keeps the ratio the same but reverses the output direction. Here is a link to the Freecad model. https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdrive.google.com%2Ffile%2Fd%2F1QX6cw-zHwiRNLSGqVZV_AoieQYPtvKRB%2Fview%3Fusp%3Dsharing&data=04%7C01%7Ctoddz%40pgrahamdunn.com%7C5ce70ebbb0d143330dd508d9bf32e1f5%7C5758544c573f47cebee96c3e0806fb43%7C0%7C0%7C637751048404394852%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=h1ePHRAQKLaTDCRlsHUxq3ODzsXgQAQEDzGg3nCfPyY%3D&reserved=0 This doesn't render here Todd, its a text list of colors. Making the difference between driven and output two teeth, still works out to mesh correctly but makes the output ratio 34:1. (100t/40t:102t/42t) Which I think might be about the perfect ratio for the rack and pinion drive on my router (to replace it's barely adequate 10:1 belt.) However I'd probably be better off simply buying a readily available off the shelf 30:1 planetary gear box for that. Were I to do that idea in openscad, I'd union the two different pinions and print 4 of them. Not having access to your model, probably a mimetype error here, do you have an axle bearing per gear, or could I just use one gear per unionized pair? It seems to me that both bearings would be needed to resist the twisting moment on the pinions under load. I've now installed freecad, and will dl the link and see if that will show me what you have. 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<mailto:jo...@autoartisans.com>> Sent: Tuesday, December 14, 2021 12:30 AM To: 'Enhanced Machine Controller (EMC)' <emc-users@lists.sourceforge.net<mailto:emc-users@lists.sourceforge.net>> Subject: Re: [Emc-users] Harmonic Drive [EXTERNAL EMAIL] Be sure links are safe. Todd, I'm not sure I 'get' how it works with the pinned gears. I built a different kind of flex cup drive based on a paper on what is called an HGD_EWG_Drive https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.geartechnology.com%2Fissues%2F1013x%2Fharmonic_drive.pdf&data=04%7C01%7Ctoddz%40pgrahamdunn.com%7C5ce70ebbb0d143330dd508d9bf32e1f5%7C5758544c573f47cebee96c3e0806fb43%7C0%7C0%7C637751048404404837%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=sqS9DyYADHEEp2K6XU98Jl%2FtEHd%2FuVsehu7vaajW8Fk%3D&reserved=0 Here's a really short video of the version of one I created. I used that earlier 3D print harmonic drive for the base tooth form although this type looks like you can use involute profile or even belt profile as the flex teeth follow a circular rather than elliptical gear. Something to play with now that I have some PETG. https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fyoutu.be%2Flb6shTgQ1wY&data=04%7C01%7Ctoddz%40pgrahamdunn.com%7C5ce70ebbb0d143330dd508d9bf32e1f5%7C5758544c573f47cebee96c3e0806fb43%7C0%7C0%7C637751048404404837%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=L1ZCbk4vQLNwth%2BjgY7JpQQh1a6LD9UN6ePO7Kk5Z2o%3D&reserved=0 I really need to bring in a bigger stepper to play with this. The surplus unit with about 1A at 36V will stall if I even look at it cross eyed. Here's the original I was playing with along side the new one. https://nam04.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.autoartisans.com%2Fharmonicdrive%2FHarmonicDrive-35.jpg&data=04%7C01%7Ctoddz%40pgrahamdunn.com%7C5ce70ebbb0d143330dd508d9bf32e1f5%7C5758544c573f47cebee96c3e0806fb43%7C0%7C0%7C637751048404404837%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=ee87%2FTZuN1zEfVCblcYSCnxYyJhVwGscGNyrzoy5M%2Bs%3D&reserved=0 I still don't have the right size bearings but did have these tiny ones I bought 20 years ago at a model aircraft show in the UK. So I created bearings that were 22mm diameter. Big issue there they were really only 21.3mm after printing and that caused all sorts of issues because I forgot that detail. I then printed some oversize, created an arbor for them on the lathe and turned them down to 22mm. Now I get 100% connection and zero backlash. This things spins so smoothly just by placing a finger on the wave cup driver and pushing it around. And you can't hold onto the output. https://nam04.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.autoartisans.com%2Fharmonicdrive%2FHarmonicDrive-29.jpg&data=04%7C01%7Ctoddz%40pgrahamdunn.com%7C5ce70ebbb0d143330dd508d9bf32e1f5%7C5758544c573f47cebee96c3e0806fb43%7C0%7C0%7C637751048404404837%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=98y0KPsDgP0XL%2FwerNJsD4C0iXkSYx3PIXPoI%2FNy1WU%3D&reserved=0 And here's a diagram of most of the bits and pieces. https://nam04.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.autoartisans.com%2Fharmonicdrive%2FHarmonicDrive-28.jpg&data=04%7C01%7Ctoddz%40pgrahamdunn.com%7C5ce70ebbb0d143330dd508d9bf32e1f5%7C5758544c573f47cebee96c3e0806fb43%7C0%7C0%7C637751048404404837%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=rdvZ%2B4gMMR8YZX4iZCMJnZQY41q82NsnTQCCcG8%2Faw4%3D&reserved=0 The main bearings are utility trailer 1" ID roller bearings. I'm waiting for 6101 and 6103 bearings to arrive. Most of the parts will be made from metal. John Dammeyer > -----Original Message----- > From: Todd Zuercher > [mailto:to...@pgrahamdunn.com<mailto:to...@pgrahamdunn.com>] > Sent: December-03-21 8:37 AM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] Harmonic Drive > > It was easier to model in Freecad than I expected. I'll try to attach a jpg > of it and see if it goes through. > > And if it doesn't go through a link to it on my Google drive. > https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdriv > e.google.com%2Ffile%2Fd%2F1_eSu-olALMsevTnOpzQ1o1r_rPjfexwU%2Fview%3Fu > sp%3Dsharing&data=04%7C01%7Ctoddz%40pgrahamdunn.com%7C5ce70ebbb0d1 > 43330dd508d9bf32e1f5%7C5758544c573f47cebee96c3e0806fb43%7C0%7C0%7C6377 > 51048404404837%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2l > uMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=kFLK8IVVRbugQyeTs > Zl77AYP%2BQsgwBuVgrvUjR9ysb4%3D&reserved=0 > > Here is a link to the Freecad file (Freecad v0.18). > https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdriv > e.google.com%2Ffile%2Fd%2F1GGwG9nzmYowKeuMAWMvOExeGrvSzZCnY%2Fview%3Fu > sp%3Dsharing&data=04%7C01%7Ctoddz%40pgrahamdunn.com%7C5ce70ebbb0d1 > 43330dd508d9bf32e1f5%7C5758544c573f47cebee96c3e0806fb43%7C0%7C0%7C6377 > 51048404404837%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2l > uMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=GePtOJMld%2FrrTNk > HQTQRqAUXh6OWIGDv8Ry8p2%2FoMTo%3D&reserved=0 > > > Todd Zuercher > P. Graham Dunn Inc. > 630 Henry Street > Dalton, Ohio 44618 > Phone: (330)828-2105ext. 2031 > > -----Original Message----- > From: Andy Pugh <bodge...@gmail.com<mailto:bodge...@gmail.com>> > Sent: Thursday, December 02, 2021 6:40 PM > To: Enhanced Machine Controller (EMC) > <emc-users@lists.sourceforge.net<mailto:emc-us...@lists.sourceforge.ne > t>> > Subject: Re: [Emc-users] Harmonic Drive > > [EXTERNAL EMAIL] Be sure links are safe. > > > On 2 Dec 2021, at 21:14, Todd Zuercher > > <to...@pgrahamdunn.com<mailto:to...@pgrahamdunn.com>> wrote: > > > > What if you used two outer ring gears of the same diameter one with > > one fewer teeth. Then have 4 sets of planetaries stacked in > pairs. Each pair would be pinned together > > You can just use pinions twice as long as the ring gears. I think I > have seen this done > > It would work with all-external gears too. > > > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net<mailto:Emc-users@lists.sourceforge.net > > > https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Flist > s.sourceforge.net%2Flists%2Flistinfo%2Femc-&data=04%7C01%7Ctoddz%4 > 0pgrahamdunn.com%7C5ce70ebbb0d143330dd508d9bf32e1f5%7C5758544c573f47ce > bee96c3e0806fb43%7C0%7C0%7C637751048404404837%7CUnknown%7CTWFpbGZsb3d8 > eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3 > 000&sdata=pqeO%2FLq%2FcybqqS5iWHkNI2aKp%2BeQi12xvTnziOJVgJA%3D& > ;reserved=0 > users&data=04%7C01%7Ctoddz%40pgrahamdunn.com%7Ce891b8fadd884297a79 > 608d9b5ed4669%7C5758544c573f47cebee9 > 6c3e0806fb43%7C0%7C0%7C637740852975732935%7CUnknown%7CTWFpbGZsb3d8eyJW > IjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJ > BTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=16s%2BM61vPdzTAtr3Qg6ttYn > RU6%2Fg4vkOsrYcbPRxmuY%3D&reserv > ed=0 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net<mailto:Emc-users@lists.sourceforge.net> https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.sourceforge.net%2Flists%2Flistinfo%2Femc-users&data=04%7C01%7Ctoddz%40pgrahamdunn.com%7C5ce70ebbb0d143330dd508d9bf32e1f5%7C5758544c573f47cebee96c3e0806fb43%7C0%7C0%7C637751048404404837%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=G2%2BTBO5nRNBAppBprf6PDt%2FR8nCJRCruQMI6o5%2FbeVY%3D&reserved=0 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.sourceforge.net%2Flists%2Flistinfo%2Femc-users&data=04%7C01%7Ctoddz%40pgrahamdunn.com%7C5ce70ebbb0d143330dd508d9bf32e1f5%7C5758544c573f47cebee96c3e0806fb43%7C0%7C0%7C637751048404404837%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=G2%2BTBO5nRNBAppBprf6PDt%2FR8nCJRCruQMI6o5%2FbeVY%3D&reserved=0 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
