Machining Bevels.
Re: Machining Bevels.
I think all the calculations for a stanard involute are correct, just have to do one more function to them. Imagine a spur gear and the flat plane on the side of the spur gear, now all of a sudden that flat plane is spherical? Image the teeth. They are still an involute, just the world they live in is now a sphere. Now imagine 2 spur gears working together on parallel shafts, no imagine the flat plane on the side has become a sphere and the 2 shafts are now at right angles. Gives more meaning to me now of the work spherical involute. :-)
Re: Machining Bevels.
Damo:
To the first question: I cant imagine that piece of paper, though Im sure you can. Its the problem with such dicusions, their very hard
to describe in words. To the second comment.. exactly, I think when you take that spur tooth and fold it into a sphere you create a spherical
involute whos pattern of contact is then an octiod if its done correctly. Are mine? Christ only knows. I know they mesh very well, but if they pattern
on a figure 8... beats me.
When I do finish the non-circ's in GT, I will visit the Gcode generator to add bevels. Since we're speaking only of using a ground cutter for these
the GCode will work fine no matter if we're rigth or wrong..the entire issue will be the cutter shape.. so we'll see.. :)
Ill have the Gcode put out so that the blank will have to be tilted to root angle..
Art
To the first question: I cant imagine that piece of paper, though Im sure you can. Its the problem with such dicusions, their very hard
to describe in words. To the second comment.. exactly, I think when you take that spur tooth and fold it into a sphere you create a spherical
involute whos pattern of contact is then an octiod if its done correctly. Are mine? Christ only knows. I know they mesh very well, but if they pattern
on a figure 8... beats me.
When I do finish the non-circ's in GT, I will visit the Gcode generator to add bevels. Since we're speaking only of using a ground cutter for these
the GCode will work fine no matter if we're rigth or wrong..the entire issue will be the cutter shape.. so we'll see.. :)
Ill have the Gcode put out so that the blank will have to be tilted to root angle..
Art
Re: Machining Bevels.
Hi Art, I tried to draw what I meant. Sort of looks like a potato chip. The line passes through 2 sets of axes at the same angle. From the side it looks like a figure 8. Imagine the rack going around the circumference and 2 opposite tooth flanks are on the surface.
Cheers Damo
Not sure if this will work, am attaching 2 images
Cheers Damo
Not sure if this will work, am attaching 2 images
Re: Machining Bevels.
I see what you mean, it is a figure 8 on profile.. Im just not sure how that helps me in terms of getting the rigth profile..
Its interesting to note that the specification for the calculation of the bevel toothform produces a very bad looking curve in the
axial plane..its only once you fold that to spherical that the curve looks correct as a semi-evolute..
Art
Its interesting to note that the specification for the calculation of the bevel toothform produces a very bad looking curve in the
axial plane..its only once you fold that to spherical that the curve looks correct as a semi-evolute..
Art
Re: Machining Bevels.
Damo:
Just found this out there..
>>While gear manufacturing is well developed, with precision gears cut under
tight tolerances and producing smooth motions, the geometry of gear meshing
is not yet fully exploited in the industry. For example, bevel gears are
still designed using Tredgold?s approximation, under which the tooth profile
is designed so as to yield a projection onto the tangent plane of the back cone
that matches the profile of an equivalent involute spur gear.
This IS what Im doing. The tooth form IS created to be correct as a typical spur when viewed from the
tangent plane on the back face..
This link explains how to make the correct (if thats the correct word) method..
http://www.geometrie.tuwien.ac.at/stach ... g_Proc.pdf
As you can see, its not something Ill jump into lightly. :)
Art
Just found this out there..
>>While gear manufacturing is well developed, with precision gears cut under
tight tolerances and producing smooth motions, the geometry of gear meshing
is not yet fully exploited in the industry. For example, bevel gears are
still designed using Tredgold?s approximation, under which the tooth profile
is designed so as to yield a projection onto the tangent plane of the back cone
that matches the profile of an equivalent involute spur gear.
This IS what Im doing. The tooth form IS created to be correct as a typical spur when viewed from the
tangent plane on the back face..
This link explains how to make the correct (if thats the correct word) method..
http://www.geometrie.tuwien.ac.at/stach ... g_Proc.pdf
As you can see, its not something Ill jump into lightly. :)
Art
Re: Machining Bevels.
Out of those 5 theorems, they lost me at the first. :D
Cheers Damo
Cheers Damo
Re: Machining Bevels.
Actually, i'm just happy i understand the word "octoid" now.
Re: Machining Bevels.
Words just dont work..do they. :)
Art
Art
Re: Machining Bevels.
Hey Art, Anything new with the bevels or are You busy working on other things?
Re: Machining Bevels.
Hi:
Bevels will be dealt with in a waterline engraving module, but probably not till next fall.
Art
Bevels will be dealt with in a waterline engraving module, but probably not till next fall.
Art
Re: Machining Bevels.
Art,
Here is another paper on spiral bevel gear generation and inspection.
http://gear-net.com/report/rep-03.html
Also Klingelnberg method is in a spread sheet with macros that create tooth form for Solid Works IGES inport.
https://www.youtube.com/watch?v=k-WdPTxinZk
Chuck in Wyoming
Here is another paper on spiral bevel gear generation and inspection.
http://gear-net.com/report/rep-03.html
Also Klingelnberg method is in a spread sheet with macros that create tooth form for Solid Works IGES inport.
https://www.youtube.com/watch?v=k-WdPTxinZk
Chuck in Wyoming
Re: Machining Bevels.
Naively, it seems like the easiest way to cut bevel gears on a 3-axis CNC machine would be to generate a gear profile numerically, and then profile cut with a ball nose end mill, but I haven't seen any discussion of that in the thread. Is there some compelling reason not to take that approach?ArtF wrote: Hi:
Bevels will be dealt with in a waterline engraving module, but probably not till next fall.
...
Re: Machining Bevels.
Nate:
Thats the plan. Its not easy to cut bevels, but for beverls less than 45 degrees, the workbench shoudl be
able to profile them, for more than 45 degrees, he 4th axis shoudl eb able to profile them..
Art
Thats the plan. Its not easy to cut bevels, but for beverls less than 45 degrees, the workbench shoudl be
able to profile them, for more than 45 degrees, he 4th axis shoudl eb able to profile them..
Art
Re: Machining Bevels.
A bevel gear with lots of helicity, a small pressure angle, and large teeth can have both radial and axial overhangs. (That is to say, require a 'tilt' or 5th axis set up.) I'm not sure whether gears like that have any practical application.ArtF wrote: That's the plan. Its not easy to cut bevels, but for bevels less than 45 degrees, the workbench should be
able to profile them, for more than 45 degrees, he 4th axis should be able to profile them..
This is a section of a decorative bevel gear I modeled. If the pitch cone angle were larger, you can see that there would be a 'double undercut'.
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