Autodesk: Discussion Groups - True involute gear generation

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Replies: 10 - Last Post: Jul 24, 2009 5:49 PM Last Post By: 2grumpy

shona_narec

Posts: 7
Registered: 02/23/09

True involute gear generation
Posted: Apr 16, 2009 7:51 AM

Hi

I need to produce a true involute gear profile, (Mod 16, 11 tooth, 20deg pressure angle). The profile needs to be 'true' as it's going to be wire eroded, rather than hobbed, and the profile will be needed for the CAM software.

DA's gears are for appearance only - I was wondering if anyone knows of a program for creating true involutes. It's either that or get the Machinery's handbook out and start sketching.........

Thanks

Shona

Ales Ricar \(Au...

Re: True involute gear generation
Posted: Apr 16, 2009 10:19 AM

in response to: shona_narec

gear-profile.JPG (93.3 KB)

Hello Shona,

In fact, if you are using Inventor 2010 you may leverage new capabilities of
Design Accelerator and create precise spur gear model.

You just need a spur gear set inserted in your assembly. Then, you may use
RMB and select "Export tooth shape" command (see the picture enclosed). This
allows you export geometry of the tooth into a new part document. You can
also adjust desired clearance (backlash) of the profle during export. You
may complete the gear model as you need and use it instead of simplified
parametric model of the gear. You may also specify "No Model" option within
Spur Gears Component Generator panel as this allows you to don't create
simplified version of gear model.

Regards, Ales

wrote in message news:6163330@discussion.autodesk.com...
Hi I need to produce a true involute gear profile, (Mod 16, 11 tooth, 20deg
pressure angle). The profile needs to be 'true' as it's going to be wire
eroded, rather than hobbed, and the profile will be needed for the CAM
software. DA's gears are for appearance only - I was wondering if anyone
knows of a program for creating true involutes. It's either that or get the
Machinery's handbook out and start sketching......... Thanks Shona

2grumpy

Posts: 73
Registered: 11/26/07

Re: True involute gear generation
Posted: Jun 25, 2009 12:49 AM $in response to: Ales Ricar \(Au...$ in response to: Ales Ricar \(Au...

It is fantastic
In the future will you have similar facility for bevel gears?

MarcoA

Re: True involute gear generation
Posted: Apr 16, 2009 3:04 PM

in response to: shona_narec

shona_narec ha scritto:

Hi I need to produce a true involute gear profile, (Mod 16, 11 tooth,
20deg pressure angle). The profile needs to be 'true' as it's going to
be wire eroded, rather than hobbed, and the profile will be needed for
the CAM software. DA's gears are for appearance only - I was wondering
if anyone knows of a program for creating true involutes.

http://www.kisssoft.ch/

--
AIS 11 SP4
Pentium 4 3 GHz - 2 GB RAM
NVIDIA Quadro 330 6.14.10.9136

MarkC-UK

Posts: 264
Registered: 11/24/05

Re: True involute gear generation
Posted: Apr 16, 2009 8:58 PM

in response to: MarcoA

Spur Gear Tutorial.pdf (1.3 MB)

Is the attached tutorial any use to you? I grabbed it from mcadforums ages ago.

ifuks

Posts: 205
Registered: 07/02/07

Re: True involute gear generation
Posted: Apr 16, 2009 9:43 PM

in response to: shona_narec

I use this program I downloaded from Cadalog long time ago. It calls 3Dgear. Just a lisp file that works. Run it in AutoCAD and then transfer geometry to the sketch and extrude in IV

jjuhlin

Posts: 5
Registered: 04/16/09

Re: True involute gear generation
Posted: Apr 17, 2009 3:13 AM

in response to: shona_narec

I don't know of any canned application and the information in Machinery's handbook is not much good for drawing the involute curve. But Shigley's Machine Design has a very easy layout method that can be used to create as many discrete points along the curve as you wish to make. Plotting polyline to fit through the points will yield a very acceptably accurate curve. I draw the curve in ACAD and then import the sketch. I just had to do this the other day and and it only took a short time.

shona_narec

Posts: 7
Registered: 02/23/09

Re: True involute gear generation
Posted: Apr 17, 2009 10:40 AM

in response to: jjuhlin

Hi guys

Thanks for the replies - lots of good suggestions. I downloaded a IV2010 and installed it on a 30 day trial, and generated the 'true' profile from within there, then STEPed it out to IV2008, which seems to have done the trick.

Thanks again.

Shona

gearhead22

Posts: 2
Registered: 04/26/09

Re: True involute gear generation
Posted: Apr 26, 2009 2:52 PM

in response to: shona_narec

shona

There are only hand full of equation to define the involute. The trochoid is most demanding. Make sure you get true gear geometry that is including both True Involute Gear Profile + True Trochoid Profile. Some programs draws the true involute (that's the easy part), then connects at tangential curve from the involute curve to the center point. It would then just simply add a fillet radius at the root. That is NOT the right way to create the trochoid profile.

In order to create the troichoid profile, it would need to follow the hobbing action. If you don't get that right, you would not get the proper tip clearance. This problem is hugely magnified on pinions with few teeth.

As an active member of AGMA committee, I have spent lot of time studying this on my own. I can create the CAD model for you for a small fee. Please let me know if I could help you.
You can reach me at: true.involute.gear@gmail.com

Please feel free to visit my site and download a sample of my work at: http://gearhead22.netau.net/ or http://true-involute-gear.comxa.com/

I have exported the sample part to STEP and Para-Solid (.x_t) formats.

F099y

Posts: 2
Registered: 06/03/09

Re: True involute gear generation
Posted: Jun 3, 2009 8:14 PM

in response to: shona_narec

10tgear.jpg (121.6 KB)

I have software that i have written in Visual Basic that produces a perfect involute, it will save the involute in dxf format that you can open up in AutoCad and manipulate to produce a perfect gear with perfect involute form.

Data Needed:

No of Teeth
Mod or Dp
PA
Major Diameter
Minor Diameter
Tooth Thickness

Comes with full instructions.

You can produce the gear form in minutes.

If interested e-mail ......(gored5@aol.com)

F099y

Posts: 2
Registered: 06/03/09

Re: True involute gear generation
Posted: Jun 23, 2009 7:50 PM

in response to: shona_narec

www.f099y.webs.com

See a demo of my involute software here.

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