hirth joint
Since a new thread was requested, I'm starting a new thread. I completed
an implementation based on the principles I previously described of tilting
the triangle. One thing that I didn't make clear is that even though the
errors are small at high tooth counts, those errors can make the polyhedron
invalid. Part of the intention of my approach was to construct the hirth
joint as a single polyhedron. If you're willing to accept that a 30 tooth
joint is a 60 sided polyhedron then you don't need the extra complications
of intersecting with a tube.
I thought it would be a simple matter to round the valleys, but I was
wrong. I can round the tooth tips, but not the valleys because the tilt of
the triangle causes a rounding profile to stick out and create a funny
ridge along the valley. Perhaps the approach can be adapted to use
projection instead of tilt?
Here's a 16 tooth example:
[image: image.png]
Here's 8 teeth:
[image: image.png]
Code is attached. A significant amount of complication arose from
calculating the location of the bottoms of the valleys in the case where
you crop the part with a cylinder. Code attached.
I have posted my explanation here:
https://github.com/sprabhakar2006/openSCAD/blob/main/explanation%20of%20approaches/explanation%20hirth%20coupling.pdf
because the file size became 1.5 mb
On Mon, 4 Nov 2024 at 07:38, Adrian Mariano via Discuss <
discuss@lists.openscad.org> wrote:
Since a new thread was requested, I'm starting a new thread. I completed
an implementation based on the principles I previously described of tilting
the triangle. One thing that I didn't make clear is that even though the
errors are small at high tooth counts, those errors can make the polyhedron
invalid. Part of the intention of my approach was to construct the hirth
joint as a single polyhedron. If you're willing to accept that a 30 tooth
joint is a 60 sided polyhedron then you don't need the extra complications
of intersecting with a tube.
I thought it would be a simple matter to round the valleys, but I was
wrong. I can round the tooth tips, but not the valleys because the tilt of
the triangle causes a rounding profile to stick out and create a funny
ridge along the valley. Perhaps the approach can be adapted to use
projection instead of tilt?
Here's a 16 tooth example:
[image: image.png]
Here's 8 teeth:
[image: image.png]
Code is attached. A significant amount of complication arose from
calculating the location of the bottoms of the valleys in the case where
you crop the part with a cylinder. Code attached.
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
And the YouTube video is here in case anyone is interested :
https://youtu.be/Wp8q71eMqrE?si=fY1AxbXp8itbZRm7
On Mon, 4 Nov 2024, 08:10 Sanjeev Prabhakar, sprabhakar2006@gmail.com
wrote:
I have posted my explanation here:
because the file size became 1.5 mb
On Mon, 4 Nov 2024 at 07:38, Adrian Mariano via Discuss <
discuss@lists.openscad.org> wrote:
Since a new thread was requested, I'm starting a new thread. I completed
an implementation based on the principles I previously described of tilting
the triangle. One thing that I didn't make clear is that even though the
errors are small at high tooth counts, those errors can make the polyhedron
invalid. Part of the intention of my approach was to construct the hirth
joint as a single polyhedron. If you're willing to accept that a 30 tooth
joint is a 60 sided polyhedron then you don't need the extra complications
of intersecting with a tube.
I thought it would be a simple matter to round the valleys, but I was
wrong. I can round the tooth tips, but not the valleys because the tilt of
the triangle causes a rounding profile to stick out and create a funny
ridge along the valley. Perhaps the approach can be adapted to use
projection instead of tilt?
Here's a 16 tooth example:
[image: image.png]
Here's 8 teeth:
[image: image.png]
Code is attached. A significant amount of complication arose from
calculating the location of the bottoms of the valleys in the case where
you crop the part with a cylinder. Code attached.
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
A lot of discussion but it doesn't look like a useful coupling to me as it
will always try to force itself apart. Wouldn't straight sided teeth with a
chamfer to aid initial engagement be better.
On Mon, 4 Nov 2024 at 02:47, Sanjeev Prabhakar via Discuss <
discuss@lists.openscad.org> wrote:
And the YouTube video is here in case anyone is interested :
https://youtu.be/Wp8q71eMqrE?si=fY1AxbXp8itbZRm7
On Mon, 4 Nov 2024, 08:10 Sanjeev Prabhakar, sprabhakar2006@gmail.com
wrote:
I have posted my explanation here:
because the file size became 1.5 mb
On Mon, 4 Nov 2024 at 07:38, Adrian Mariano via Discuss <
discuss@lists.openscad.org> wrote:
Since a new thread was requested, I'm starting a new thread. I
completed an implementation based on the principles I previously described
of tilting the triangle. One thing that I didn't make clear is that even
though the errors are small at high tooth counts, those errors can make the
polyhedron invalid. Part of the intention of my approach was to construct
the hirth joint as a single polyhedron. If you're willing to accept that a
30 tooth joint is a 60 sided polyhedron then you don't need the extra
complications of intersecting with a tube.
I thought it would be a simple matter to round the valleys, but I was
wrong. I can round the tooth tips, but not the valleys because the tilt of
the triangle causes a rounding profile to stick out and create a funny
ridge along the valley. Perhaps the approach can be adapted to use
projection instead of tilt?
Here's a 16 tooth example:
[image: image.png]
Here's 8 teeth:
[image: image.png]
Code is attached. A significant amount of complication arose from
calculating the location of the bottoms of the valleys in the case where
you crop the part with a cylinder. Code attached.
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
I think the point is that it wedges together with good alignment and no
slop. Square teeth would need a clearance gap and then there would be
backlash.
On Mon, Nov 4, 2024 at 04:49 nop head via Discuss <
discuss@lists.openscad.org> wrote:
A lot of discussion but it doesn't look like a useful coupling to me as it
will always try to force itself apart. Wouldn't straight sided teeth with a
chamfer to aid initial engagement be better.
On Mon, 4 Nov 2024 at 02:47, Sanjeev Prabhakar via Discuss <
discuss@lists.openscad.org> wrote:
And the YouTube video is here in case anyone is interested :
https://youtu.be/Wp8q71eMqrE?si=fY1AxbXp8itbZRm7
On Mon, 4 Nov 2024, 08:10 Sanjeev Prabhakar, sprabhakar2006@gmail.com
wrote:
I have posted my explanation here:
because the file size became 1.5 mb
On Mon, 4 Nov 2024 at 07:38, Adrian Mariano via Discuss <
discuss@lists.openscad.org> wrote:
Since a new thread was requested, I'm starting a new thread. I
completed an implementation based on the principles I previously described
of tilting the triangle. One thing that I didn't make clear is that even
though the errors are small at high tooth counts, those errors can make the
polyhedron invalid. Part of the intention of my approach was to construct
the hirth joint as a single polyhedron. If you're willing to accept that a
30 tooth joint is a 60 sided polyhedron then you don't need the extra
complications of intersecting with a tube.
I thought it would be a simple matter to round the valleys, but I was
wrong. I can round the tooth tips, but not the valleys because the tilt of
the triangle causes a rounding profile to stick out and create a funny
ridge along the valley. Perhaps the approach can be adapted to use
projection instead of tilt?
Here's a 16 tooth example:
[image: image.png]
Here's 8 teeth:
[image: image.png]
Code is attached. A significant amount of complication arose from
calculating the location of the bottoms of the valleys in the case where
you crop the part with a cylinder. Code attached.
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
@nop head nop.head@gmail.com
, these type of joints are typically loaded, so they cannot just pop off.
Another take on the theme, if someone develops a profile they like on one
side, they should be able to use a geometrical diff operation to form the
mating surface without slop. That said, the profile has to be symmetric to
accommodate the adjustment.
Hope this helps.
On Mon, Nov 4, 2024 at 8:24 AM Adrian Mariano via Discuss <
discuss@lists.openscad.org> wrote:
I think the point is that it wedges together with good alignment and no
slop. Square teeth would need a clearance gap and then there would be
backlash.
On Mon, Nov 4, 2024 at 04:49 nop head via Discuss <
discuss@lists.openscad.org> wrote:
A lot of discussion but it doesn't look like a useful coupling to me as
it will always try to force itself apart. Wouldn't straight sided teeth
with a chamfer to aid initial engagement be better.
On Mon, 4 Nov 2024 at 02:47, Sanjeev Prabhakar via Discuss <
discuss@lists.openscad.org> wrote:
And the YouTube video is here in case anyone is interested :
https://youtu.be/Wp8q71eMqrE?si=fY1AxbXp8itbZRm7
On Mon, 4 Nov 2024, 08:10 Sanjeev Prabhakar, sprabhakar2006@gmail.com
wrote:
I have posted my explanation here:
because the file size became 1.5 mb
On Mon, 4 Nov 2024 at 07:38, Adrian Mariano via Discuss <
discuss@lists.openscad.org> wrote:
Since a new thread was requested, I'm starting a new thread. I
completed an implementation based on the principles I previously described
of tilting the triangle. One thing that I didn't make clear is that even
though the errors are small at high tooth counts, those errors can make the
polyhedron invalid. Part of the intention of my approach was to construct
the hirth joint as a single polyhedron. If you're willing to accept that a
30 tooth joint is a 60 sided polyhedron then you don't need the extra
complications of intersecting with a tube.
I thought it would be a simple matter to round the valleys, but I was
wrong. I can round the tooth tips, but not the valleys because the tilt of
the triangle causes a rounding profile to stick out and create a funny
ridge along the valley. Perhaps the approach can be adapted to use
projection instead of tilt?
Here's a 16 tooth example:
[image: image.png]
Here's 8 teeth:
[image: image.png]
Code is attached. A significant amount of complication arose from
calculating the location of the bottoms of the valleys in the case where
you crop the part with a cylinder. Code attached.
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
Hi Adrian,
the rounding of the valleys is a manufacturing requirement, (couldn't
get long lasting grinding disks with sharp corners) the flat tops to the
crests, is so they don't bottom out.
The initial code I submitted worked fine with the parameters I gave, but
no others.
My second, version, which I used to generate the images, worked fine as
parametric, but I have not been on line for a day or so, and I am
reconstructing that code, having not saved it, and it seems file history
is not working.
If you can generate bevel gears, then you should be able to make Curvic
couplings.
On 04/11/2024 02:07, Adrian Mariano via Discuss wrote:
Since a new thread was requested, I'm starting a new thread. I
completed an implementation based on the principles I previously
described of tilting the triangle. One thing that I didn't make clear
is that even though the errors are small at high tooth counts, those
errors can make the polyhedron invalid. Part of the intention of my
approach was to construct the hirth joint as a single polyhedron. If
you're willing to accept that a 30 tooth joint is a 60 sided
polyhedron then you don't need the extra complications of intersecting
with a tube.
I thought it would be a simple matter to round the valleys, but I was
wrong. I can round the tooth tips, but not the valleys because the
tilt of the triangle causes a rounding profile to stick out and create
a funny ridge along the valley. Perhaps the approach can be adapted
to use projection instead of tilt?
Here's a 16 tooth example:
image.png
Here's 8 teeth:
image.png
Code is attached. A significant amount of complication arose from
calculating the location of the bottoms of the valleys in the case
where you crop the part with a cylinder. Code attached.
OpenSCAD mailing list
To unsubscribe send an email todiscuss-leave@lists.openscad.org
@Raymond West raywest@raywest.com, actually, I think the rounded corners
is generally an engineering requirement. Sharp edges are stress-risers,
causing cracks and breaks. That said, not having to grinding into a
sharp corner makes things a LOT easier ;-)
On Mon, Nov 4, 2024 at 11:41 AM Raymond West via Discuss <
discuss@lists.openscad.org> wrote:
Hi Adrian,
the rounding of the valleys is a manufacturing requirement, (couldn't get
long lasting grinding disks with sharp corners) the flat tops to the
crests, is so they don't bottom out.
The initial code I submitted worked fine with the parameters I gave, but
no others.
My second, version, which I used to generate the images, worked fine as
parametric, but I have not been on line for a day or so, and I am
reconstructing that code, having not saved it, and it seems file history is
not working.
If you can generate bevel gears, then you should be able to make Curvic
couplings.
On 04/11/2024 02:07, Adrian Mariano via Discuss wrote:
Since a new thread was requested, I'm starting a new thread. I completed
an implementation based on the principles I previously described of tilting
the triangle. One thing that I didn't make clear is that even though the
errors are small at high tooth counts, those errors can make the polyhedron
invalid. Part of the intention of my approach was to construct the hirth
joint as a single polyhedron. If you're willing to accept that a 30 tooth
joint is a 60 sided polyhedron then you don't need the extra complications
of intersecting with a tube.
I thought it would be a simple matter to round the valleys, but I was
wrong. I can round the tooth tips, but not the valleys because the tilt of
the triangle causes a rounding profile to stick out and create a funny
ridge along the valley. Perhaps the approach can be adapted to use
projection instead of tilt?
Here's a 16 tooth example:
[image: image.png]
Here's 8 teeth:
[image: image.png]
Code is attached. A significant amount of complication arose from
calculating the location of the bottoms of the valleys in the case where
you crop the part with a cylinder. Code attached.
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
found it-
// clutch.scad
ind = 50; // overall diameter
num = 46; // number of teeth
back = 5; //thickness of back
bore = 8.3; // diameter of hole
recess = 30;// diameter of recess in centre
////////////////////////////////////////////
diam = ind/cos (180/num);
chord = diam*sin(180/num);
ridge= chord sqrt(3)/4; // or set to whatever
// Basic parameters
radius = diam / 2;
angle_per_tooth = 360 / num;
yp =radius * tan(angle_per_tooth / 2);
rp = sqrt((ypyp)+(radius*radius)); //radius to point
points = [
[0, 0, ridge / 2], // Center
[radius, -yp, 0], // Left base
[radius, yp, 0], // Right base
[radius , 0, ridge] // Peak of the ridge
];
faces=[
[0,1,2],
[0,1,3],
[0,2,3],
[1,2,3]
];
module wedge(){
polyhedron(points,faces,convexity=10);
}
//rotate wedge
module clutch(){
difference(){
intersection(){
translate([0,0,-back])
cylinder(d=ind,h=200,$fn=100);
union(){
for (j=[0:1:num-1])
rotate([0,0,j360/num]) wedge();
rotate([0,0,180/num])
cylinder(r1=rp,r2=0,h=ridge/2,$fn=num);
translate([0,0,-back])
cylinder(d=diam,h=back,$fn=num);
}
}
cylinder(d=recess,h=ridge3);
translate([0,0,-back-ridge])
cylinder (d=bore,h=(back+ridge)*3);
}
}
$fn=100;
clutch();
/*
translate([50,0,0])
// rotate([0,180,360/(num*2)])
import("P:/Docs/openscad/clutch.stl");
cube(ind,true);
*/
On 04/11/2024 16:41, Raymond West via Discuss wrote:
Hi Adrian,
the rounding of the valleys is a manufacturing requirement, (couldn't
get long lasting grinding disks with sharp corners) the flat tops to
the crests, is so they don't bottom out.
The initial code I submitted worked fine with the parameters I gave,
but no others.
My second, version, which I used to generate the images, worked fine
as parametric, but I have not been on line for a day or so, and I am
reconstructing that code, having not saved it, and it seems file
history is not working.
If you can generate bevel gears, then you should be able to make
Curvic couplings.
On 04/11/2024 02:07, Adrian Mariano via Discuss wrote:
Since a new thread was requested, I'm starting a new thread. I
completed an implementation based on the principles I previously
described of tilting the triangle. One thing that I didn't make clear
is that even though the errors are small at high tooth counts, those
errors can make the polyhedron invalid. Part of the intention of my
approach was to construct the hirth joint as a single polyhedron. If
you're willing to accept that a 30 tooth joint is a 60 sided
polyhedron then you don't need the extra complications of
intersecting with a tube.
I thought it would be a simple matter to round the valleys, but I was
wrong. I can round the tooth tips, but not the valleys because the
tilt of the triangle causes a rounding profile to stick out and
create a funny ridge along the valley. Perhaps the approach can be
adapted to use projection instead of tilt?
Here's a 16 tooth example:
image.png
Here's 8 teeth:
image.png
Code is attached. A significant amount of complication arose from
calculating the location of the bottoms of the valleys in the case
where you crop the part with a cylinder. Code attached.
OpenSCAD mailing list
To unsubscribe send an email todiscuss-leave@lists.openscad.org
OpenSCAD mailing list
To unsubscribe send an email todiscuss-leave@lists.openscad.org
You have a steeper angle, and higher tension on the centre fixing to
improve grip, I guess. The idea of the tapered sides is for ease of
manufacturing. To get vertical sides, then it would involve more passes
of the grinding wheel/mill. With a 'V' shape, you get more strength at
the root, compared to square, (acme thread is stronger than square, plus
can use a split nut - not relevant in this case).
On 04/11/2024 09:48, nop head via Discuss wrote:
A lot of discussion but it doesn't look like a useful coupling to me
as it will always try to force itself apart. Wouldn't straight sided
teeth with a chamfer to aid initial engagement be better.
On Mon, 4 Nov 2024 at 02:47, Sanjeev Prabhakar via Discuss
discuss@lists.openscad.org wrote:
And the YouTube video is here in case anyone is interested :
https://youtu.be/Wp8q71eMqrE?si=fY1AxbXp8itbZRm7
On Mon, 4 Nov 2024, 08:10 Sanjeev Prabhakar,
<sprabhakar2006@gmail.com> wrote:
I have posted my explanation here:
https://github.com/sprabhakar2006/openSCAD/blob/main/explanation%20of%20approaches/explanation%20hirth%20coupling.pdf
because the file size became 1.5 mb
On Mon, 4 Nov 2024 at 07:38, Adrian Mariano via Discuss
<discuss@lists.openscad.org> wrote:
Since a new thread was requested, I'm starting a new
thread. I completed an implementation based on the
principles I previously described of tilting the
triangle. One thing that I didn't make clear is that even
though the errors are small at high tooth counts, those
errors can make the polyhedron invalid. Part of the
intention of my approach was to construct the hirth joint
as a single polyhedron. If you're willing to accept that
a 30 tooth joint is a 60 sided polyhedron then you don't
need the extra complications of intersecting with a tube.
I thought it would be a simple matter to round the
valleys, but I was wrong. I can round the tooth tips, but
not the valleys because the tilt of the triangle causes a
rounding profile to stick out and create a funny ridge
along the valley. Perhaps the approach can be adapted to
use projection instead of tilt?
Here's a 16 tooth example:
image.png
Here's 8 teeth:
image.png
Code is attached. A significant amount of complication
arose from calculating the location of the bottoms of the
valleys in the case where you crop the part with a
cylinder. Code attached.
_______________________________________________
OpenSCAD mailing list
To unsubscribe send an email to
discuss-leave@lists.openscad.org
_______________________________________________
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
OpenSCAD mailing list
To unsubscribe send an email todiscuss-leave@lists.openscad.org
