helical gear with the trajpar feature

[dibloff]

Hi everyone

I'd like to model a helical gear with ProE. For this first I'll create a datum curve for the evolvent, second another datum curve for the helical trajectory. And third an advanced cut - variable section sweep using parameter "trajpar".
Does anyone know how to make it?
I know only the idea, but I never manage to model it.

THX

 

[3dlogix]

Trajpar (trajectory parameter) is used in a skecther relationship to control a variable section sweep (VSS). Things to remember:
Trajpar goes from 0 to 1 (think of it as 0 to 100%).
Trajpar must only exist in s sketcher relation such as;

sd1=evalgraph("graphname",100*trajpar)

The only variables you put in are the "graphname" that must be created earlier, and the value of the graph x-axis length. In this case, it was 100. If the actual graph x-axis is say, 175, then, any number upto but not over 175 is valid. So if you want to evaluate the trajpar at half the graph x-axis, then it would be 87.5 in this case.


You can also enter relations such as: sd5=(R1-TRAJ_RADIUS)+(R2-R1)*(trajpar-1/(2*pi)*sin(360*trajpar)) [from PTC]
to create cam surfaces.


Steve

http://www.3dlogix.com

 

[dibloff]

I'm creating an evolvent curve with cylindrical coordinate system with the following relations

alfay=t*50
r=db/(2*cos(alfay))
fiy=tan(alfay)-(alfay*PI/180)
theta=fiy*180/PI

where
db - is the base diameter, calculated previously.
Then I'm creating a helical curve, also parametrically, for that length which is necessary for the cut. The problem is, that Pro Engineer does not rotate the sketch through the curve, the sketch will be always vertical. (or as it was in the sketch).
The problem could be solved if we rotate the sketch along the curve by help of the trajpar parameter. But the sketch is connected to the datum curve (evolvent).

So this is the problem. Do somebody know how to solve it?