iteration equation in relations

[ptc-2614450]

hi all, i am designing a gear in pro-e. I use parameters, relations, family table to automate the gear modelling. i have to write a equation to find the working pressure angle which could be done by newton's iteration procedure.There is 'solver' option in Excel to do this. Do we hav a function like that in pro-e?
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[ptc-230676]

I think the functionality you are looking for is part of the behavioral modeling module in Pro/Engineer. Also: If Excel already have this functionality you can let Excel do the calculations using the excel analysis option in Pro/Engineer.

[ptc-2614450]

thanks for ur response, i'll try this in behaviour modeling and get back to you...

[DavidButz]

Mohamed, Actually, nothing fancy is required. You can do a "solve" operation within relations. See the article "Suggested Technique for Creating an Involute Gear" in the Pro/E Knowledge Base. http://www.ptc.com/cs/cs_24/howto/agf652/agf652.htm in which the following relations create the involute geometry: rbase=A1 todeg=180/pi solve a*todeg-atan(a)=trajpar*A2 for a sd4=rbase*(1+a^2)^0.5 If you are not familiar with it, trajpar is a parameter associated with a Variable Section Sweep which varies continuously from 0 to 1 as the geometry develops, following the principal trajectory. David

[ptc-2614450]

"solve ----- for " thanks for this david.. can u get solution for this "solve 0.0149=tan(a)-((pi/180)*a) for a"

[DavidButz]

M. I'm not immediately sure what your "a" is. However, there is no reason you can't successfully solve for it. What you need to do is use trajpar to get your "iterated" solution over the geometric range of interest. If you look carefully at the model in the linked article and the form of the equations, you should be able to do the equivalent with your formulae. What you will need to create is an appropriate trajectory. Your tooth profile will be created by a mathematically swept surface generally following (not attached to) the trajectory and governed by your equations which will be iteratively and continuously solved as trajpar changes continuously from 0 to 1 while the geometry is being swept. D.

[DavidButz]

A little more detail. The attached drawing should make things a little clearer. (Click on the thumbnail, then click on the image again in imageshack to see it clearly.) Also, there seems to be an error in the PTC article; I believe DTM1 should be set at 10 degrees, not 30, according to the values shown in the illustrations. Another thing you can explore if you're interested is creating a Datum Curve by Equation. If you do, you will be creating parametric equations which depend on a parameter t which (like trajpar) varies from 0 to 1 to establish the range of evaluation. If you create such a curve, you will have to copy it with a Sketched Curve to generate additional geometry. Finally, it is a good idea to use the Quilt technique suggested in the article to produce the numerous teeth on your gear. If you create the teeth with solid cuts or protrusions and pattern them, Regeneration will be much slower. David

[DavidButz]

To create the same geometry with a Curve By Equation, use the Cylindrical Option and the Following Input: a=1 solve a*180/pi-atan(a)=14*t for a r=8*(1+a^2)^.5 theta=14+6*t z=0

[ptc-2512492]

The above messages are right, of course. There are multiple ways to do "design study" type things. Since Pro/E files are, really, programs... they have all variety of programming functionality you can use. In my case, I like doing this using the MathCAD interface... but that's just personal preference.