topic Re: Constructing internal bevel gear in Inventor Forum

Constructing internal bevel gear

hyeock91 — Mon, 01 Apr 2019 15:27:07 GMT

I am new to Inventor and have some trouble with creating an internal gear.

https://forums.autodesk.com/t5/inventor-forum/internal-bevel-gears/td-p/5954862

This post helped me a lot with my work, so I was able to create the gear surface from the 2D sketch on the left.

My goal is to create the 3D solid of this internal bevel gear so that I can 3D print the prototype.

I simply tried to loft a solid from the 2D sketch but selecting two sketches on top and bottom for solid lofting was somehow not possible.

As...a result, the lofted surface on the right was the best result I could build.

Any suggestion to build a solid gear from here?

Thanks

Re: Constructing internal bevel gear

BrennanJWilkie — Mon, 01 Apr 2019 15:55:49 GMT

I went to try to open the file, but it seems you are on a newer version than I am (2016). As far as the loft not working, there are a few things to consider:

1) Are both drawings fully closed? Sometimes when a shape isn't closed, you will end up with it making a surface (your orange one on the right) instead of a solid. You can check this by zooming in on the points where two lines attach at a corner. If you find that they aren't attached, go to your constraints tab inside the sketch you are working on, and there will be a button that shows a 90 degree angle with a little box at the corner. Click on this button, then on each of the points you want to have on top of one another. Keep in mind that while doing this, it might affect other parts of the sketch.

2) Do the teeth need to get bigger at the bottom (I'm not used to working with bevel gears, so if this is one of the basic things about them, then ignore this)? Would it still be able to work if you had them be the same size?

I'm going to take a crack at making one and see if I can get a method that will work for you.

Re: Constructing internal bevel gear

Sergio.D.Suárez — Mon, 01 Apr 2019 15:56:48 GMT

hi, are you trying to do something like this?
Greetings, I hope you can solve your problem.

Re: Constructing internal bevel gear

graemev — Mon, 01 Apr 2019 19:37:23 GMT

Those are extraordinarily, and unnecessarily, complicated sketches. A simpler way is to either model one tooth and use a circular pattern or extrude the body, extrude-cut one tooth, and use a circular pattern for the rest.

Given that this is to become the actual part, not a graphical representation, you probably should extrude the tooth profile as an involute tooth form laid out perpendicular to the pitch line of the tooth. This will involve setting up an appropriate sketch plane, laying out a pair of involute curves based on the gear tooth profile and bevel gear parameters.

Been there, done that, for a pair of external bevel gears (also 3D printed) and doing so is substantially less than a trivial assignment for a novice. More power to you if you can handle it, but this is an elephant of many, many bites.

Pinion attached. (Drag the EOP marker to the bottom once loaded. Originally generated in 2014.) Take a peek at the parameters for an idea of what you're dipping your toes into.

Re: Constructing internal bevel gear

hyeock91 — Tue, 02 Apr 2019 02:22:28 GMT

Thanks for your support!

Fortunately, I got what I wanted from the other replies.

I am not sure if my sketches were not closed(though it does seem so taking other discussions in the forum) but I was able to overcome my problem with patch and stitch function.

Thank you again.

Re: Constructing internal bevel gear

hyeock91 — Tue, 02 Apr 2019 02:25:45 GMT

Thanks!

This was exactly what I wanted!

I didn't know about stitch and patch functions, and you gave me the answer.

I was able to regenerate your result with my ipt file.

Thank you again with your help!

Re: Constructing internal bevel gear

hyeock91 — Tue, 02 Apr 2019 02:36:20 GMT

Hi! Thank you for your answer.

I noticed that your approach is the usual one that people use to generate gear.

Just that, I have been utilizing the 'gear generator' implanted in inventor assembly.

I am also designing other gears with the gear generator, so I wanted to find a way to deal with my problem using sketches from 'gear generator'.

Thanks for your sketch you attached to your reply, but I was trying to build an internal bevel gear.

Fortunately, the other comment above gave me the answer I was looking for.

I really appreciated your support!