Bevel Gear Construction

[Anonymous]

I am trying to create bevel gears.  As per this guide, I am starting with a 3d sketch and want to get the gear pictured on the right.

The  guide says:

"You can now create a scaled copy of each outline along the appropriate axis, using a 3D scaling operator with the origin set at the point where the axes intersect; be careful with this step, as using an incorrect origin will result in gears that would not mesh. With this step out of the way, the scaled copy and the original can be then lofted together, and each of them can be individually extruded toward any point behind the gear to create a cap surface. A few extra moves to trim and cap everything neatly, and you should have a final result in front of you:"

Does Inventor have a 3D scaling operator with a settable origin point? Can they be lofted together and create the caps?

[swalton]

For a "good-enough" representation of a bevel gear set, take a look at the Bevel Gear Generator.  See http://help.autodesk.com/view/INVNTOR/2014/ENU/?guid=GUID-CCF86460-FCBA-4647-9DD9-F11CA860936F

I'm not sure if the tooth profile on the models is exactly correct for real components, so if you plan to produce these gears, you may have to adapt the instructions from your guide to generate the correct profile on the Gear Generator parts.  The gear generators usually work fine for off-the-shelf gears.

Take a look at what you can get from Boston Gear, Stock Drive Components, or McMaster Carr.

[Anonymous]

Thanks, but I would still like to know of there is a way to do this in Inventor. 

[TheCADWhisperer]

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@Anonymous wrote:

Thanks, but I would still like to know of there is a way to do this in Inventor. 

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Yes.

Inventor is a Computer Aided Design (CAD) program.

[Anonymous]

>Yes.

>Inventor is a Computer Aided Design (CAD) program.

Would you care to share how?  I would like to get the workflow in Inventor then implement it in the API.  Thanks for any help.

[TheCADWhisperer]

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@Anonymous wrote:

>Yes.

>Inventor is a Computer Aided Design (CAD) program.

Would you care to share how?

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No.

I don't have the time.

Is there a school near you that offers classes on mechanical design?

[Anonymous]

Then your reply is unhelpful and unwanted.  

[Mark.Lancaster]

@Anonymous

Before anybody can show you anything..  How much experience do you have in Inventor and what version are you using?

[Anonymous]

I am using Inventor 2017.   I am new to Inventor, but I have been using Maya for 15 years and I know what I want to do in Inventor, I just don't know how to get what I want.

As mentioned in the link, I'm looking to scale the gear relative to an origin point, then enclose the two pieces to form a solid.

[WHolzwarth]

Best way is using a sample dataset.

- Number of Teeth for Bevel gear 1

- Number of Teeth for Bevel gear 2

- Pressure angle

- Module

- Axis angle (normally 90°)

- Tooth width

These above are the main inputs.

Tell us, what you want, and we can show you, what Inventor can do.

Walter

[Anonymous]

I have the gear outlines already created in 3D sketches.  As in the OP, I have two 3D sketches of the bevel gears that I would like to make solids.  I'm trying to figure out a way to extrude the 3D sketch to create the bevel gear.  One way is to make a scaled version from a reference point.  Another way is to extrude a 3D solid which Inventor does not support.

[WHolzwarth]

Can you attach your files?

[swalton]

The workflow you reference in the tutorial looks like it was intended for a surface modeler like Rhino. The workflow in Inventor will be a bit different. I would try lofting an individual tooth, then patterning it in a circle, then adding the web and hub of the gear with a revolve feature.

@graemev posted a pinon and driven gear set using that technique in this thread: http://forums.autodesk.com/t5/inventor-general-discussion/drawing-a-bevel-gear/td-p/5272861 Roll down the EOP marker to see the modeling technique. You can make changes with the parameters window to change the number of teeth, angle, diameters, etc. I think these models use an involute tooth form so they should mesh ok, but not carry as much power as a commercial set.

You haven't said if you need to manufacture the gears from your model or if you will be buying a commercial set. That answer will determine how much work you will have to do on your model. Spur gears use an involute tooth form, which seems like a good start, but according to wikipedia, commercial bevel gears use a stronger tooth form called an octoid. See: https://en.wikipedia.org/wiki/Bevel_gear

If you want an idea of how much detail goes into a commercial set, take a look at this page:http://www.geartechnology.com/articles/0315/A_Practical_Approach_for_Modeling_a_Bevel_Gear Note that the author does not recommend using this method if you are planning on performing detailed FEA of the gears.

My recommendation would be to use the Bevel Gear Generator to create a close-enough model of a commercial set and then purchase the set for your machine. If you can't find a commercial set that meets your requirements, I would contact a local gear manufacturer to make one to your specs, and make a quick-n-dirty set without teeth for your model. If you must make your own, use the models from @graemev and live with the weaker tooth form.  I don't see any advantage in trying to use the technique shown in your tutorial.

Edited for format.

[Anonymous]

Attached is the 3D sketch of one of the bevel gears.

[Anonymous]

Thanks you for the thoughtful reply.  I really appreciate it.

I really do not like the gear generators in Inventor.  I spend too much time fighting them.   The reason to make my own is to make them quickly and easily.

I will probably not be able to buy a commercial set due to the sizes I will need.

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@swalton wrote:

I would try lofting an individual tooth, then patterning it in a circle, then adding the web and hub of the gear with a revolve feature.

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I will try that.  Thank you.

[swalton]

I did not realize you were the author of the Gearbakery software from this post:  https://forums.autodesk.com/t5/inventor-general-discussion/gear-bakery-builds-spur-gears-internal-ge...  That looks like a neat program.

I agree that the gear generators (and all of the design accelerator programs) can be painful to use.  I think that Autodesk could do a better job explaining how the various settings and adjustments change the output.  I also don't like the fact that the gear generators do not make 3d models with real toothforms.  

Do you plan on linking your Gearbakery program with the Inventor part files so that the user can change gear parameters to update the Inventor model?  I would be disappointed if I had to fix broken constraints or downstream features because I decided that I needed to change from a 41 to a 43 tooth gear during the design process.

How do you plan to manufacture your own gears?  

[WHolzwarth]

Here's a possible way of doing (2017 IPT)

Walter

[Anonymous]

My initial thought was to make the Gear Bakery an Inventor plugin, but the
SDK is in such a bad shape, this is not an easy task. Many of the samples
do not build and the SDK has not been updated in three years.

I certainly want to make this useful. I had not considered the update
process. Is it possible to tie a third party program to a part? If not, I
will revisit the plugin option since I have become more familiar with the
Inventor API.

[Anonymous]

@WHolzwarth  Thanks for the completed part, but I need the steps to create the gear so I can implement it in the API.

[Anonymous]

@WHolzwarth  The completed part has a lot of good info.  I can dissect it to get what I need.  Now if I can the the API to perform the functions I need.