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  #1  
Old 10-18-2002, 12:25 PM
Michel Gendron Michel Gendron is offline
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Location: LeMoyne, Québec, Canada
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Exclamation Gears calculation

Hi folk,
I'm searching for some macro/software that can generate the real teeth profil of a gear. I need to play with the "involute" function to create "undercut" and so on on the gear.

Anybody got Idea where I can find this tool (for free or for sale...)

Michel
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  #2  
Old 10-18-2002, 12:36 PM
Mike Robbins Mike Robbins is offline
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I know of some software that will make the complete gear, it makes several different types of gears. I heard that the next release of it will include undercuts.

nagatool located at:
http://www.nagasoftware.com
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  #3  
Old 10-21-2002, 07:30 AM
bfisher bfisher is offline
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Michel,

I was given this info a few years ago from a company that we built some gear stamping tooling for. It's a formula for creating an approximation of a gear tooth, and I have found that it does a reasonably good job. I have compared it to the spline geometry that is generated from the Mastercam gear tooth program and found the maximum error to be wothin .001. This may or may not be good enough for your application, but it will at least give you a start. Good Luck,
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  #4  
Old 10-22-2002, 04:56 AM
jkramer's Avatar
jkramer jkramer is offline
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I wrote a lisp routine that models one tooth of the desired gear by cutting it with a "straight tooth profile" (sorry, don't know the english word).
Here's the lisp code:

(use-package :OLI)

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;


(sd-defdialog 'gear

:dialog-title "Gear"

:variables
'(
(mdl :initial-value nil :value-type :number :title "modul")
(z :initial-value nil :value-type :number :title "no of teeth")
)

:local-functions
'(
(doit ()
(create_workplane :new)
(c_line_inf :horizontal 0,0)
(c_line_inf :vertical 0,0)
(geometry_mode :real)

(circle :cen_rad
(gpnt2d 0 0)
(gpnt2d (+ mdl (* 0.5 (* mdl z))) 0)
)
(extrude :auto_direction :yes :sel_part "/gear" :distance 5 :direction :-W :keep_profile :no)
;
(polygon
(gpnt2d (* -1 (* mdl 1.2403609563)) (- (* 0.5 (* mdl z)) (* 1.25 mdl)) )
(gpnt2d 0 (+ (* 0.5 (* mdl z)) (* mdl 2.157863719)) )
(gpnt2d (* mdl 1.2403609563) (- (* 0.5 (* mdl z)) (* 1.25 mdl)) )
(gpnt2d (* mdl 1.570796327) (- (* 0.5 (* mdl z)) (* 1.25 mdl)) )
(gpnt2d (* mdl 1.570796327) (+ 1 (+ (* 0.5 (* mdl z)) (* mdl 2.157863719))) )
(gpnt2d (* -1 (* mdl 1.570796327)) (+ 1 (+ (* 0.5 (* mdl z)) (* mdl 2.157863719))) )
(gpnt2d (* -1 (* mdl 1.570796327)) (- (* 0.5 (* mdl z)) (* 1.25 mdl)) )
:CLOSE)
;
(MOVE_2D :SELECT :edge_2d :all_2d :HORIZONTAL (* -6.283185307 mdl) )
;
(dotimes (counter 80 "done")
(punch :parts "/gear")
(MOVE_2D :SELECT :edge_2d :all_2d :HORIZONTAL (* 0.05 (* 3.141592654 mdl)) )
(position_pa :part_assembly "/gear" :rotate :axis :two_pta 0,0,0 0,0,1 :rotation_angle (/ -360 (* 20 z)) :done)
)
;
(circle :cen_rad
(gpnt2d 0 0)
(gpnt2d (- (* 0.5 (* mdl z)) (* 1.25 mdl)) 0)
)
(C_LINE_INF :ANGLE 0,0 (- 90 (/ 900 z)) )
(C_LINE_INF :ANGLE 0,0 (- 90 (/ 720 z)) )
(C_LINE_INF :ANGLE 0,0 (- 90 (/ 540 z)) )
))
:ok-action
'(doit)
)


Hope this works!
Regards,
Jaap Kramer
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  #5  
Old 10-22-2002, 12:50 PM
Michel Gendron Michel Gendron is offline
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Location: LeMoyne, Québec, Canada
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Thumbs up Thanks all

Thanks for you reply. I wrote an e-mail to Naga's support and they will support undercutting, tooth thickening, pinion expansion, and various non-agma tooth profiles such as PTG profiles in v12. So I think it's the best investment I can do.

Thanks again for your reply

Michel
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  #6  
Old 10-30-2002, 07:51 AM
ChrisE's Avatar
ChrisE ChrisE is offline
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Location: Grünstadt, Pfalz, Germany
Posts: 121
Wink

Hi there,

I'd like to add two notes to the LISP code of JKramer:

a) You should ALWAYS be using "sd-call-cmds" when calling SD commands from within a user-defined dialog.
Example:
(sd-call-cmds (create_workplane :new))
or
(sd-call-cmds (progn
(create_workplane :new)
(rectangle (gpnt2d 0 0) (gpnt2d 50 100))
))

(as SD commands are "terminating commands" - they tend to terminate your dialog. So even if your code seems to be successful - don't rely on it)

b) LISP has a constant named PI
(so you don't have to key in these akward numbers)

Cheers,

Chris
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  #7  
Old 11-14-2006, 04:04 PM
Joe Chang Joe Chang is offline
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Posts: 24
Re: Gears calculation

Quote:
Originally Posted by bfisher View Post
Michel,

I was given this info a few years ago from a company that we built some gear stamping tooling for. It's a formula for creating an approximation of a gear tooth, and I have found that it does a reasonably good job. I have compared it to the spline geometry that is generated from the Mastercam gear tooth program and found the maximum error to be wothin .001. This may or may not be good enough for your application, but it will at least give you a start. Good Luck,
Thank you Bfishsher for post this useful data.
But I am sorry that I still did not know relationship about "B" distance and R "F" can you explain more detail or plot a 2D file for my reference please

Thank you again!
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  #8  
Old 11-15-2006, 04:23 AM
tom kirkman's Avatar
tom kirkman tom kirkman is offline
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Location: Perrysburg, Ohio
Posts: 397
Re: Gears calculation

Michel

I have a program that was written for us several years ago that does true involute gear profiles to AGMA standards.

It was written for spur gears. The spur gear portion has been proven to be accurate. Later helical, bevel and pinion options were added. The company that wrote it went out of business, so they sent me the full code for it. I reworked the bevel gear for accuracy and wrote a mathcad program for the correct inputs. I have not had a need yet for the helical gear to see if it works properly.

The code has no copyright so I can get you a copy if you would like.

Tom
Attached Files
File Type: lsp GearDesigner.lsp (183.6 KB, 1340 views)
File Type: doc GearDesigner.doc (194.5 KB, 1566 views)
File Type: zip Bevel Gear.zip (25.8 KB, 1458 views)

Last edited by tom kirkman; 11-16-2006 at 04:25 AM. Reason: Added File
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  #9  
Old 11-19-2006, 10:03 AM
filippide_mf filippide_mf is offline
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Location: Rome
Posts: 2
Red face Re: Gears calculation

Quote:
Originally Posted by tom kirkman View Post
Michel

I have a program that was written for us several years ago that does true involute gear profiles to AGMA standards.

It was written for spur gears. The spur gear portion has been proven to be accurate. Later helical, bevel and pinion options were added. The company that wrote it went out of business, so they sent me the full code for it. I reworked the bevel gear for accuracy and wrote a mathcad program for the correct inputs. I have not had a need yet for the helical gear to see if it works properly.

The code has no copyright so I can get you a copy if you would like.

Tom
Bye

I have try the lisp gear designer but the model is very small, i use solid designer in MM. The bore is coretly but the diameter pitch i very small .
Where is the problem

Thanks

Marco
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  #10  
Old 11-20-2006, 04:56 AM
tom kirkman's Avatar
tom kirkman tom kirkman is offline
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Location: Perrysburg, Ohio
Posts: 397
Re: Gears calculation

Marco

The metric setup still uses diametral pitch and not module of the gear. Diametral pitch is the inverse of module.

Module = pitch diameter/number of teeth.
diametral pitch = number of teeth/pitch diameter.

If the module is 5, then the diametral pitch is 1/5 or .2.

Try this to see if it helps.

Tom
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  #11  
Old 11-21-2006, 02:05 AM
filippide_mf filippide_mf is offline
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Re: Gears calculation

Quote:
Originally Posted by tom kirkman View Post
Marco

The metric setup still uses diametral pitch and not module of the gear. Diametral pitch is the inverse of module.

Module = pitch diameter/number of teeth.
diametral pitch = number of teeth/pitch diameter.

If the module is 5, then the diametral pitch is 1/5 or .2.

Try this to see if it helps.

Tom
Very thanks Tom
now is good

thankssssssss

bye
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  #12  
Old 11-29-2006, 08:16 AM
fjsa fjsa is offline
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Re: Gears calculation

Hallo
Problem mit Gear Designer V1.6 von tom kirkman.
Ich habe den im Modeling geladen, aber es kommt diese Fehlermeldung.
Meine Umgebung OSDModeling V14.50.
Ich kann leider die englische Sprache nicht.
Gruß aus München
Achim
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  #13  
Old 11-29-2006, 09:09 AM
tom kirkman's Avatar
tom kirkman tom kirkman is offline
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Re: Gears calculation

Hallo Ich benutze babelfish, um zu übersetzen, also hoffe ich, daß dieses verständlich ist.

Erscheint diese fehler, wenn sie GearDesigner lädt?

Erscheint diese fehler wenn sie ein Zahnrad bildet?

welche Art vom Zahnrad bilden Sie?

Tom

"Hello

I am using babelfish to translate so I hope this is understandable.

Do the errors appear when loading GearDesigner?

Do the errors apper when creating a gear?

What type of gear are you trying to create?

Tom
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  #14  
Old 11-29-2006, 11:54 PM
fjsa fjsa is offline
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Re: Gears calculation

Hello
I thank the translation understood, Babelfish am a good tip.
The errors message appears if I a gear wheel to form wants.
The inputs of the Pinion from GearDesigner.doc used.
Then the following geometry is formed. From Lisp programming I do not have notion.
Can't it be the LISP of the GearDesigner with LISP of the Modeling V14.5 is compatible?
Greeting from Munich
Achim
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  #15  
Old 11-30-2006, 03:35 AM
Henk Stokkel Henk Stokkel is offline
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Re: Gears calculation

Sie gebrauchen metric and inches ducheinander.
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