Helical sweep of datum curve?

[mekaneck]

I am trying to model a helical gear using a true involute profile, but I cannot figure out how to create a helical sweep of a datum curve. I had to create the involute tooth profile using an equation, but now I cannot sweep it along a helical path because I cannot use the use edge in sketcher because it cannot move the geometry of the datum curve.



Below is a picture of my setup:



View attachment 148



I have tried a regular sweep, a VSS, a helical sweep, making one side of the tooth at a time with a surface, etc. but to no avail. I am using 2001.

 

[mekaneck]

I'd still like to find a way to do this. In the equation for the curves, I can control the angle of the curve about the axis of the gear, and I can control the depth (both with variables). I would think that this would be all that is needed to make this possible, but there is no way to get ProE to drive either of the variables in a sweep.



Here are some related questions that could help:



Is it possible to sketch an equation without using a datum curve (i.e. in sketcher)?



Is it possible to twist a surface or solid geometry (if I made a spur gear, could I somehow twist it to make it into a helical gear) ?



Thanks in advance for any help.

 

[mekaneck]

Well, I think I've got something that'll work -



I used the copy geometry tool in sketcher to copy my datum curve, then (while still in sketcher) I selected that copied curve and used the rotate/scale tool to rotate the curve, and then I used that angular dimension in conjunction with the trajpar variable in a VSS.



When I rotated the curve, it looks like it broke it up into a bunch of smaller arcs, but they all act as a single entity when I select it, so I don't know if this is still a true involute curve or just a representation, but it's as close as I'm going to get.



Any other ways to go about this would still be appreciated.

 

[tinag]

I downloaded a gear several days ago. It is a helical gear but the angle of the sweep is adjustable so that you can change it into a spur gear. If you want i can send you a copy of this gear.



It may help you to find out how it is done.



Tinag

 

[mekaneck]

I've looked at that one before. It helped me get started, but it doesn't have a true involute tooth, and it is also done with a swept blend. I am looking for a way to make the actual geometry, not an approximation.



I appreciate the help though.