Jump to content
spinecad

How to 2D Draw A Tooth of Gear?

Recommended Posts

spinecad

Hi,

 

Could anybody please give me an easy example of how to create a 2D drawing (standard mechanical engineering drawing) of one tooth of gear such as below image?

 

http://i47.tinypic.com/fbi82g.png

 

Thank you

Share this post


Link to post
Share on other sites
ReMark

One way is to get yourself a book that explains the process or look it up on line.

 

A second option would be to use a custom lisp routine that draws 2D gears, input the required data, let the routine draw the complete gear, take what you need and erase the remainder.

 

This was ridiculously easy to find...http://www.cartertools.com/involute.html

Share this post


Link to post
Share on other sites
JD Mather

Metric or inch?

Are you willing to work through the entire process - beginning to end (read, not so easy)?

What textbook are you using?

Do you have a specific size?

Information like

# of teeth?

pitch?

 

Do you have MS Excel?

Share this post


Link to post
Share on other sites
spinecad
Metric or inch?

Are you willing to work through the entire process - beginning to end (read, not so easy)?

What textbook are you using?

Do you have a specific size?

Information like

# of teeth?

pitch?

 

Do you have MS Excel?

 

Inch.

 

Yes.

 

Mechanical Design of Machine Elements and Machines – A Failure Prevention Perspective by Jack A. Collins.

 

No.

 

Just the one.

 

Any.

 

Yes I have.

Share this post


Link to post
Share on other sites
JD Mather

 

Just the one.

 

 

I understand that you only want to draw one tooth, but in order to draw that one tooth you must know how many total teeth are on the gear.

 

There are two ways to draw the gear (tooth), the more complex involute curve and a simplified representation using the Wellman's Odontograph method.

 

I will start with the Wellman's technique and make up parameters since you don't seem to have any starting information.

Let me go find my spreadsheet.

Share this post


Link to post
Share on other sites
JD Mather

I do not have any idea of your training or experience with AutoCAD - so I will start out very basic and slow.

Once I know you are following along OK, then I will post the spreadsheet.

 

Draw 3 circles and one vertical line with the dimensions shown (I recommend you color-code these even though I didn't).

Attach your dwg file of what you have completed so far.

 

Gear Start.jpg

 

(I have to do it this step-by-step method as students frequently ask questions like this and then disappear after a couple of steps.) I am taking this information from the texbook by Giesecke, et al Technical Drawing.

Share this post


Link to post
Share on other sites
spinecad
I do not have any idea of your training or experience with AutoCAD - so I will start out very basic and slow.

Once I know you are following along OK, then I will post the spreadsheet.

 

Draw 3 circles and one vertical line with the dimensions shown (I recommend you color-code these even though I didn't).

Attach your dwg file of what you have completed so far.

 

[ATTACH=CONFIG]39367[/ATTACH]

 

(I have to do it this step-by-step method as students frequently ask questions like this and then disappear after a couple of steps.) I am taking this information from the texbook by Giesecke, et al Technical Drawing.

 

My AutoCAD skill is good.

 

Next I will attached the .dwg file.

Share this post


Link to post
Share on other sites
spinecad
I do not have any idea of your training or experience with AutoCAD - so I will start out very basic and slow.

Once I know you are following along OK, then I will post the spreadsheet.

 

Draw 3 circles and one vertical line with the dimensions shown (I recommend you color-code these even though I didn't).

Attach your dwg file of what you have completed so far.

 

[ATTACH=CONFIG]39367[/ATTACH]

 

(I have to do it this step-by-step method as students frequently ask questions like this and then disappear after a couple of steps.) I am taking this information from the texbook by Giesecke, et al Technical Drawing.

This is the .dwg file.

Gear.dwg

Share this post


Link to post
Share on other sites
JD Mather
My AutoCAD skill is good.

 

You have exploded dimensions - a sure way to fail my class. :(

 

I forgot about this thread - I will post the next couple of steps in a few minutes.

Share this post


Link to post
Share on other sites
JD Mather

Draw these two red lines at 20° angle and then draw red circle tangent to the angled line.

pressure angle.jpg

Share this post


Link to post
Share on other sites
JD Mather

Next draw this cyan (blue) arc and yellow arc.

The centers of these arcs are on the red circle.

There is a bit of a trick to locating the center points - post back if you don't know the trick.

 

involute.jpg

 

Post your file here when you have finished this step.

Share this post


Link to post
Share on other sites
spinecad
Next draw this cyan (blue) arc and yellow arc.

The centers of these arcs are on the red circle.

There is a bit of a trick to locating the center points - post back if you don't know the trick.

 

[ATTACH=CONFIG]39374[/ATTACH]

 

Post your file here when you have finished this step.

 

I don't know the trick.

Gearb.dwg

Share this post


Link to post
Share on other sites
JD Mather

The trick is to simply draw a circle with the desired radius (in this case big_R or r.2675) with the center at a location that you do know. Where that circle passes through the reference circle is one of two possible locations for the desired centerpoint. The one of the two possible points you need is visually obvious.

 

Center Trick.PNG draw second yellow arc at rightmost intersection of yellow arc shown and red arc. Delete the original yellow circle and trim the second yellow circle beween the pitch circle and the addendum circle as shown in my earlier post.

Repeat for little_r

Share this post


Link to post
Share on other sites
spinecad
The trick is to simply draw a circle with the desired radius (in this case big_R or r.2675) with the center at a location that you do know. Where that circle passes through the reference circle is one of two possible locations for the desired centerpoint. The one of the two possible points you need is visually obvious.

 

[ATTACH=CONFIG]39378[/ATTACH] draw second yellow arc at rightmost intersection of yellow arc shown and red arc. Delete the original yellow circle and trim the second yellow circle beween the pitch circle and the addendum circle as shown in my earlier post.

Repeat for little_r

 

This is my gear in the attached .dwg file.

 

Why the shape of the tooth is different compared to the attached image?

Gear.jpg

Gearc.dwg

Share this post


Link to post
Share on other sites
spinecad

Where is its epicycloid and the hypocycloid?

Share this post


Link to post
Share on other sites
JD Mather

Where did that come from.

I didn't instruct you to do that?

In my first reponse I asked if you could follow instructions!

 

I guess I didn't write it exactly like that, but

Are you willing to work through the entire process - beginning to end (read, not so easy)?

 

I was walking you to the solution step-by-step. You missed my last step.

Post file that looks like #13.

Edited by JD Mather

Share this post


Link to post
Share on other sites
spinecad
Where did that come from.

I didn't instruct you to do that?

In my first reponse I asked if you could follow instructions!

 

I guess I didn't right it exactly like that, but

 

I was walking you to the solution step-by-step. You missed my last step.

Post file that looks like #13.

 

I thought that was the last step.

 

I will post the .dwg file that looks like #13.

Share this post


Link to post
Share on other sites
ReMark

Got to pay attention in class.

Share this post


Link to post
Share on other sites
spinecad

This is the .dwg file that looks like #13.

Geard.dwg

Share this post


Link to post
Share on other sites
JD Mather

Now draw circle with center at intersection of yellow circle and red circle as shown.

 

Big_R.PNG

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×