unable to add spur gear

[Anonymous]

Hi everyone,

I'm having problem adding spur gear to a project. I have a part of a circle/ring and I want to be able to move it through a gear on a shaft. Both of the structures are circular so in my (uninformed) opinion I should be able to make spur gear. But I'm never allowed to select the green part. The idea is that by rotating the shaft the green part will move. It is my first time making any gear connection so I might be overlooking some basics. Could anyone help me make this rotational movement possible? 

Thank you

[JDMather]

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@Anonymous wrote:

It is my first time...

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An assembly must include parts.

In Inventor, these are of the form *.ipt files.

[Anonymous]

sorry about that, here they are

[JDMather]

What gear ratio do you want?

What is you desired center to center distance?

What is your current center to center distance?

[Anonymous]

I would like the gear ratio to be 3

[JDMather]

Do you have any other critical information to share?

Are you working off of an existing design?

[Anonymous]

No, I'm the one who is making the design. The gear ratio is not that important,  I just had an idea how this device should look/work and I'm trying to implement it but since I'm not that familiar with Inventor the process is slow and I'm adjusting the design as I go. In my first design the rotor was on a side, but i couldn't make that work so i thought i would try different approach (the one I send).  In other words everything expect for the size and shape of the green part can be changed/ adjusted. I just need to get the green part to move via gear and I was not able to put the teeth on the green part 

[JDMather · Accepted solution]

@Anonymous 

Examine the Attached files very carefully to figure out what I did.

The Gear Generator creates simplified Wellman's Odontograph toothforms rather than true Involute toothforms.

Next we will need to investigate how to export true involute toothforms so that there is no interference.

[Anonymous]

I'm really sorry to bother you. I really did try to understand how you put the spur gears there, I studied your file and tried to recreate it but with no success. I understood that you drew a new sketch which represents the diameter pitch of those gears in relation to the gear ratio. Then you extruded them as a surface, and you also thickened the pin. Don't understand why you embossed something (might have been mistake since the sketch in not constrained and doesn't seem to do anything). I understand that you also altered the holds so the center distance is 72 mm and the stand so the gear would fit.  I do understand these steps now, but when I want to create the spur gears it always creates a Calculation failure and it wont let me create the gears. It appears even in the file you attached, at least when I opened it.  Could you please tell me how exactly did you create the spur gears, I know this must be basics for you but I'm a novice and really don't know how to do it.

Thank you

[JDMather]

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@Anonymous wrote:

1. Don't understand why you embossed something (might have been mistake since the sketch in not constrained and doesn't seem to do anything). 

2. ...it always creates a Calculation failure and it wont let me create the gears. It appears even in the file you attached, at least when I opened it.   

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1. Yeah, that was just an index mark that I created when I first started working on this so that I could clearly see how the shaft was rotating (before I had any gear teeth).

2. I ignored the Calculation failure as I was going to specify my own material and use Exported Tooth form to create true involute tooth forms.  I didn't see a need to track down the load, materials, or whatever else caused the calculation failure.  I assume this isn't going into the International Space Station.  As long as there is no interference in the completed gears - I was not concerned.

[Anonymous]

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2. I ignored the Calculation failure as I was going to specify my own material and use Exported Tooth form to create true involute tooth forms.  I didn't see a need to track down the load, materials, or whatever else caused the calculation failure.  I assume this isn't going into the International Space Station.  As long as there is no interference in the completed gears - I was not concerned.

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Alright thank you I was worried I did something wrong. Could you please go through how to do the export of the tooth form. I know I click export tooth form then I select whether I want to export pinion or gear. I export it and it creates new part, there I cut out the tooth form and do the circular pattern with the same number of teeth as in the gear/pinion. But I don't know what to do next how to go back into assembly and apply these changes on the parts in my project. Thank you for your patience with me

[JDMather]

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@Anonymous wrote: But I don't know what to do next how to go back into assembly and apply these changes on the parts in my project. 

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No Easy Button (or associative) solution.  Do them over using the new gears.

Somewhere I have an Involute Gear iPart that I use rather than the Gear Generator, but it is a bit fidgety as I didn't take the time to make it robust and would take me too much effort to explain how to fix things when it acts up.

[Anonymous]

That is not the answer I was hoping for I really wanted an easy button. Thank you very much for all your help I just have one small question, in your sketch for pitch diameter you are using (for the big gear) a formula to calculate the pitch diameter using the center distance. Could you please write it down?

It was this:

(27 mm *center distance)/36 mm
I figured that could 27 stands for numer of teeth for the gear, but not sure what the 36 stands for, is it 9 (number of teeth for pinion) * 4 (module)? or is it something else? Thank you

[JDMather]

Stated Ratio 3

Pick any number of the pinion:gear teeth resulting 1:3 ratio.

Pinion t=9

Gear T=27

Given a known center-to-center distance: 

C=72

r radius of pinion

R radius of gear

R=(T*C)/(t+T)

Module will determine number of teeth for this ratio.

I simply exerimented visually in the Gear Generator till I got something that looked appropriate for this problem.

[Anonymous]

Thank you very much for all your help