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# new harmonic drive v2.xxxxxx

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## new harmonic drive v2.xxxxxx

 Greetings to all the math wizards here; I have redesigned this to use the elipse of the internal rotor as the shaping ring driver. Interposing 3 ball bearing assemblies to make the tooth bearing ring into the elipse desired But I am seeing, when I hold the parts up to the light to gauge the engagement, that the tipping of the teeth by 6 degrees a tooth as a circle of 60 are composed, the effects on the effective shape of the tooth, placing the tips of the teeth faceing out at a wider spacing than those facing inward, than the outer rings corresponding teeth facing inward, and this is creating a condition where the teeth do not slide on their mating faces, but the tips contact first, creating a high pressure, rapid wear point.  A wear point that will, as it wears in, create undesirable backlash in the assembly. So the equilateral triangles I'm using aren't quite the ideal shape. In composing the tooth, I'm doing it at 10x x-y then scaling it .1 x-y to generate the tooth.  That "scale" statement then is the ideal place to put the correction values. My question then is how much correction would be mathematically correct given that each tooth needs only the x tweek, the rotation is later. For rotation angles of 6 degrees for 60 teeth, and 5.8064516129 degrees for the 62 tooth, thereby restoring the equalatteraly that the triangles rotation destroys. FWIW. all rotations re done on center=true And equal but opposite would apply when the tooth is rotated 180 degrees to make its facing mate. So I'd need some +x for the teeth facing out and some -x for the teeth facing in.  But is it that simple? IDK. Thanks for any insight. 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 _______________________________________________ OpenSCAD mailing list To unsubscribe send an email to [hidden email]
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## Re: ***UNCHECKED*** new harmonic drive v2.xxxxxx

 A Google of gear tooth design displayed a link to https://www.engineersedge.com/gear_formula.htm Does this help? On 2021-05-06 10:12 a.m., Gene Heskett wrote: ```Greetings to all the math wizards here; I have redesigned this to use the elipse of the internal rotor as the shaping ring driver. Interposing 3 ball bearing assemblies to make the tooth bearing ring into the elipse desired But I am seeing, when I hold the parts up to the light to gauge the engagement, that the tipping of the teeth by 6 degrees a tooth as a circle of 60 are composed, the effects on the effective shape of the tooth, placing the tips of the teeth faceing out at a wider spacing than those facing inward, than the outer rings corresponding teeth facing inward, and this is creating a condition where the teeth do not slide on their mating faces, but the tips contact first, creating a high pressure, rapid wear point. A wear point that will, as it wears in, create undesirable backlash in the assembly. So the equilateral triangles I'm using aren't quite the ideal shape. In composing the tooth, I'm doing it at 10x x-y then scaling it .1 x-y to generate the tooth. That "scale" statement then is the ideal place to put the correction values. My question then is how much correction would be mathematically correct given that each tooth needs only the x tweek, the rotation is later. For rotation angles of 6 degrees for 60 teeth, and 5.8064516129 degrees for the 62 tooth, thereby restoring the equalatteraly that the triangles rotation destroys. FWIW. all rotations re done on center=true And equal but opposite would apply when the tooth is rotated 180 degrees to make its facing mate. So I'd need some +x for the teeth facing out and some -x for the teeth facing in. But is it that simple? IDK. Thanks for any insight. Cheers, Gene Heskett ``` ```-- Ron Wheeler Artifact Software 438-345-3369 [hidden email]``` _______________________________________________ OpenSCAD mailing list To unsubscribe send an email to [hidden email]
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## Re: new harmonic drive v2.xxxxxx

 In reply to this post by Gene Heskett Are you using the involute gear code available with the BOSL2 package? https://github.com/revarbat/BOSL2/wiki/gears.scad  On 5/6/2021 7:12 AM, Gene Heskett wrote: > Greetings to all the math wizards here; > > I have redesigned this to use the elipse of the internal rotor as the > shaping ring driver. Interposing 3 ball bearing assemblies to make the > tooth bearing ring into the elipse desired > > But I am seeing, when I hold the parts up to the light to gauge the > engagement, that the tipping of the teeth by 6 degrees a tooth as a > circle of 60 are composed, the effects on the effective shape of the > tooth, placing the tips of the teeth faceing out at a wider spacing than > those facing inward, than the outer rings corresponding teeth facing > inward, and this is creating a condition where the teeth do not slide on > their mating faces, but the tips contact first, creating a high > pressure, rapid wear point.  A wear point that will, as it wears in, > create undesirable backlash in the assembly. So the equilateral > triangles I'm using aren't quite the ideal shape. > > In composing the tooth, I'm doing it at 10x x-y then scaling it .1 x-y to > generate the tooth.  That "scale" statement then is the ideal place to > put the correction values. My question then is how much correction would > be mathematically correct given that each tooth needs only the x tweek, > the rotation is later. For rotation angles of 6 degrees for 60 teeth, > and 5.8064516129 degrees for the 62 tooth, thereby restoring the > equalatteraly that the triangles rotation destroys. FWIW. all rotations > re done on center=true > > And equal but opposite would apply when the tooth is rotated 180 degrees > to make its facing mate. So I'd need some +x for the teeth facing out > and some -x for the teeth facing in.  But is it that simple? IDK. > > Thanks for any insight. > > Cheers, Gene Heskett _______________________________________________ OpenSCAD mailing list To unsubscribe send an email to [hidden email]
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## Re: new harmonic drive v2.xxxxxx

 On Thursday 06 May 2021 15:25:57 Jeff Meeks wrote: > Are you using the involute gear code available with the BOSL2 package? > https://github.com/revarbat/BOSL2/wiki/gears.scad> > Not that I know of. Its all self contained in the .scad file, one of which I'll attach.  This one generates a 60 tooth spline, but changing the comment markers of the for loops will generate either a 62 or a 58 tooth version. > On 5/6/2021 7:12 AM, Gene Heskett wrote: > > Greetings to all the math wizards here; > > > > I have redesigned this to use the elipse of the internal rotor as > > the shaping ring driver. Interposing 3 ball bearing assemblies to > > make the tooth bearing ring into the elipse desired > > > > But I am seeing, when I hold the parts up to the light to gauge the > > engagement, that the tipping of the teeth by 6 degrees a tooth as a > > circle of 60 are composed, the effects on the effective shape of the > > tooth, placing the tips of the teeth faceing out at a wider spacing > > than those facing inward, than the outer rings corresponding teeth > > facing inward, and this is creating a condition where the teeth do > > not slide on their mating faces, but the tips contact first, > > creating a high pressure, rapid wear point.  A wear point that will, > > as it wears in, create undesirable backlash in the assembly. So the > > equilateral triangles I'm using aren't quite the ideal shape. > > > > In composing the tooth, I'm doing it at 10x x-y then scaling it .1 > > x-y to generate the tooth.  That "scale" statement then is the ideal > > place to put the correction values. My question then is how much > > correction would be mathematically correct given that each tooth > > needs only the x tweek, the rotation is later. For rotation angles > > of 6 degrees for 60 teeth, and 5.8064516129 degrees for the 62 > > tooth, thereby restoring the equalatteraly that the triangles > > rotation destroys. FWIW. all rotations re done on center=true > > > > And equal but opposite would apply when the tooth is rotated 180 > > degrees to make its facing mate. So I'd need some +x for the teeth > > facing out and some -x for the teeth facing in.  But is it that > > simple? IDK. > > Thanks for any insight. Thanks, Jeff Meeks 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 _______________________________________________ OpenSCAD mailing list To unsubscribe send an email to [hidden email] Outer2-60T-spline.scad (1K) Download Attachment
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## Re: new harmonic drive v2.xxxxxx

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## Re: new harmonic drive v2.xxxxxx

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## Re: new harmonic drive v2.xxxxxx

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## Re: new harmonic drive v2.xxxxxx

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## Re: new harmonic drive v2.xxxxxx

 If you have the full BOSL2 distribution you should have README.md at the top level, which contains installation instructions.   Gene Heskett wrote > > > Are you using the involute gear code available with the BOSL2 > > > package? https://github.com/revarbat/BOSL2/wiki/gears.scad> > > This I downloaded, but there is no INSTALL or README, so I wasn't able to make openscad AppImage aware of it. A question I've been meaning to ask. Sent from the OpenSCAD mailing list archive at Nabble.com._______________________________________________ OpenSCAD mailing list To unsubscribe send an email to [hidden email]
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## Re: new harmonic drive v2.xxxxxx

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## Re: new harmonic drive v2.xxxxxx

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## Re: new harmonic drive v2.xxxxxx

 In reply to this post by Gene Heskett Here's the link for BOSL2. https://github.com/revarbat/BOSL2Once you're there, click on 'Wiki" and bookmark it. There are a ton of great explanations and examples. Then download and install the code according to the README.md Gene Heskett wrote On Thursday 06 May 2021 22:08:34 adrianv wrote: > If you have the full BOSL2 distribution you should have README.md at > the top level, which contains installation instructions. > I must have gotten the wrong stuff, its named MCAD-master Sent from the OpenSCAD mailing list archive at Nabble.com._______________________________________________ OpenSCAD mailing list To unsubscribe send an email to [hidden email]
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## Re: new harmonic drive v2.xxxxxx

 On Friday 07 May 2021 00:23:17 lar3ry wrote: > Here's the link for BOSL2. > > https://github.com/revarbat/BOSL2> > Once you're there, click on 'Wiki" and bookmark it. There are a ton of > great explanations and examples. > > Then download and install the code according to the README.md > WoW!  Just rounding is many many pages.  Sweet.  Thank you. > > Gene Heskett wrote > > > On Thursday 06 May 2021 22:08:34 adrianv wrote: > >> If you have the full BOSL2 distribution you should have README.md > >> at the top level, which contains installation instructions. > > > > I must have gotten the wrong stuff, its named MCAD-master > > -- > Sent from: http://forum.openscad.org/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 _______________________________________________ OpenSCAD mailing list To unsubscribe send an email to [hidden email]
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## Re: new harmonic drive v2.xxxxxx

 In reply to this post by Msquare On Thursday 06 May 2021 19:51:13 Michael Möller wrote: I guess you will have to teach me how to use a library function from BOSL2. I have included: include include near the top of my file, and I gotten rid of the 10x render then scale, so I'm generating a regular triangle and it looks as good as ever. And I've tried to clip the outer tips with a round cylinder but seem to get unions in that the cylinder covers the triangle leaving the tips stickiong out. odd. So now I'm trying to use the BOSL2 library. But on inspection of the .local/share/OpenSCAD/libraries path, discovered that my installation was missing large parts of the .zip. fixed that, restarted OpenSCAD but apparently I don't understand the syntax example. I am getting a render abort blaming line 29, but the red dot is on line 28 for this code: for(\$fr=[ 0: 6 : 359 ]){ rotate([0, 0, \$fr]) translate([toothcirc, 0, 0]) // now lets try BOSL2. this comment Is line 28. has RED dot rounded_path=round_corners(cut=0.5) // worx w/o this line cylinder(d=toothdia, h=height, \$fn=3, center=true);         // make tall triangle }; from console window: Parsing design (AST generation)... ERROR: Parser error: syntax error in file final8-Loose_60T-inner.scad, line 29 What am I doing wrong? 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 _______________________________________________ OpenSCAD mailing list To unsubscribe send an email to [hidden email]
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## Re: new harmonic drive v2.xxxxxx

 You need a semicolon at the the end of this statement rounded_path=round_corners(cut=0.5) // worx w/o this line should be rounded_path=round_corners(cut=0.5); // worx w/o this line Gene Heskett wrote I guess you will have to teach me how to use a library function from BOSL2. I am getting a render abort blaming line 29, but the red dot is on line 28 for this code: for(\$fr=[ 0: 6 : 359 ]){ rotate([0, 0, \$fr]) translate([toothcirc, 0, 0]) // now lets try BOSL2. this comment Is line 28. has RED dot rounded_path=round_corners(cut=0.5) // worx w/o this line cylinder(d=toothdia, h=height, \$fn=3, center=true);         // make tall triangle }; Sent from the OpenSCAD mailing list archive at Nabble.com._______________________________________________ OpenSCAD mailing list To unsubscribe send an email to [hidden email]
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## Re: new harmonic drive v2.xxxxxx

 On Friday 07 May 2021 14:33:05 lar3ry wrote: > You need a semicolon at the the end of this statement > > rounded_path=round_corners(cut=0.5) // worx w/o this line > should be > rounded_path=round_corners(cut=0.5); // worx w/o this line > Made no difference. Same exact error.  Besides the semi-colon is the end of the chain marker for all the other keywords. AIUI of course.   > > Gene Heskett wrote > > > I guess you will have to teach me how to use a library function from > > BOSL2. > > I am getting a render abort blaming line 29, but the red dot is on > > line 28 for this code: > > > > for(\$fr=[ 0: 6 : 359 ]){ > > rotate([0, 0, \$fr]) translate([toothcirc, 0, 0]) > > // now lets try BOSL2. this comment Is line 28. has RED dot > > rounded_path=round_corners(cut=0.5) // worx w/o this line > > cylinder(d=toothdia, h=height, \$fn=3, center=true); > >         // make tall triangle > > }; > > -- > Sent from: http://forum.openscad.org/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 _______________________________________________ OpenSCAD mailing list To unsubscribe send an email to [hidden email]
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## Re: new harmonic drive v2.xxxxxx

 I did this and it seems to have worked. Clicked on line 40 to highlight. Then clicked on Edit -> Comment. Clicked on line 41 to highlight. Clicked Edit -> Comment. Clicked Design -> RenderI can now see an image. Trying to edit dimensions now. On Fri, May 7, 2021 at 3:40 PM Gene Heskett <[hidden email]> wrote:On Friday 07 May 2021 14:33:05 lar3ry wrote: > You need a semicolon at the the end of this statement > > rounded_path=round_corners(cut=0.5) // worx w/o this line > should be > rounded_path=round_corners(cut=0.5); // worx w/o this line > Made no difference. Same exact error.  Besides the semi-colon is the end of the chain marker for all the other keywords. AIUI of course. > > Gene Heskett wrote > > > I guess you will have to teach me how to use a library function from > > BOSL2. > > I am getting a render abort blaming line 29, but the red dot is on > > line 28 for this code: > > > > for(\$fr=[ 0: 6 : 359 ]){ > > rotate([0, 0, \$fr]) translate([toothcirc, 0, 0]) > > // now lets try BOSL2. this comment Is line 28. has RED dot > > rounded_path=round_corners(cut=0.5) // worx w/o this line > > cylinder(d=toothdia, h=height, \$fn=3, center=true); > >         // make tall triangle > > }; > > -- > Sent from: http://forum.openscad.org/ 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 _______________________________________________ OpenSCAD mailing list To unsubscribe send an email to [hidden email] _______________________________________________ OpenSCAD mailing list To unsubscribe send an email to [hidden email]
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## Re: new harmonic drive v2.xxxxxx

 In reply to this post by lar3ry On Friday 07 May 2021 14:33:05 lar3ry wrote: > You need a semicolon at the the end of this statement > > rounded_path=round_corners(cut=0.5) // worx w/o this line > should be > rounded_path=round_corners(cut=0.5); // worx w/o this line > in the docs, the shorthand example says: rounded_path = round_corners(path, , , , , , ); and "path" is not surrounded by a set of <>, what does that mean?   Everything else is an option and has a default? I don't see where path is defined by an example. A list of corners to round? Possibly in xyz order?, also tried and failed.   > > Gene Heskett wrote > > > I guess you will have to teach me how to use a library function from > > BOSL2. > > I am getting a render abort blaming line 29, but the red dot is on > > line 28 for this code: > > > > for(\$fr=[ 0: 6 : 359 ]){ > > rotate([0, 0, \$fr]) translate([toothcirc, 0, 0]) > > // now lets try BOSL2. this comment Is line 28. has RED dot > > rounded_path=round_corners(cut=0.5) // worx w/o this line > > cylinder(d=toothdia, h=height, \$fn=3, center=true); > >         // make tall triangle > > }; > > -- > Sent from: http://forum.openscad.org/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 _______________________________________________ OpenSCAD mailing list To unsubscribe send an email to [hidden email]
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