Equation Curve Involute

jmfowler1996
Advocate

Equation Curve Involute

jmfowler1996
Advocate
Advocate

Hi, guys. I am trying to create a true involute curve for a gear tooth.

 

Strangely, when I use the equation curve function and input the equation, I seem to get the involute of some other circle.

 

The equation I used was as follows:

 

X(t) = d2 * ( cos(t) + t * sin(t) )

Y(t) = d2 * ( sin(t) - t * cos(t) )

 

taken from Wolfram


Capture3.PNGCapture4.PNG

 

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Anonymous
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Accepted solution

You are using degrees instead of radians as input to sin and cos.

 

Open the part

Edit the sketch

Right click on curve->Edit Equation Curve

Select 'Show Units'

 

note that cos and sin have degrees, not radians   -> "d2 * ( sin(1 deg * t) - t * cos(1 deg * t)"

 

You can manually replace 'deg' with 'rad' in the edit box.

 

Also, reduce the 't' value upper evaluation down from 900 to 20 or so, or you will be waiting a while.

 

 

 involute.jpg

jmfowler1996
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Haha, what a rookie mistake!

 

I really never considered that. I just assumed Wolfram's equation would be in degrees.

 

Thanks for the solution. I'll make sure to check for things like this in future!

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