pulley with elliptical rays

[Mito125]

Good morning, I should draw a pulley whose rays (they are not sicuurrro call themselves rays) are elliptical. this is the photo taken from the jaw pozza discarded:If it had not had the elliptical rays I would have performed a rotation around the central axis of the section, getting a full pulley, I would have lowered through removal the central hub and executed the quarry of the wrench, I would have carried out the removal to obtain so 4 rays.
Unfortunately I can't pull out a solution regarding this elliptical section, I don't know if I should do the external and internal part of the pulley and then do an extrusion with an elliptical auxiliary plan. I don't think of anything else.
What is the best solution? Thank you.

 

[cacciatorino]

Unfortunately I can't pull out a solution regarding this elliptical section, I don't know if I should do the external and internal part of the pulley and then do an extrusion with an elliptical auxiliary plan.

Exactly, this is the road to follow. make the hub and the outer circular crown, and then a radial extrusion with a profile + strip angle, or two elliptical props with sweep type extrusion, using in this last case two different ellipses. once you make one of the "races" (they call themselves that), then make an angular series to get the others.

 

[MassiVonWeizen]

I'll get you the file I did.
to use the strip angle you must first calculate it, which can be done with an equation*, so I used the second method indicated by the hunter that is the loft**.

* creating a global variable, which inserts the equation that returns the angle, this can be recalled within the extrusion function
** when lofting is preferable to select points (in this case I have selected ellipses centers) instead of lines or curves so as to have better geometry control

note in margin: please write the software version in the profile for file compatibility; Moreover if you have modeling problems attach files so as to check that there are no problems upstream or still have indications or corrections on modeling

 

[Mito125]

Thanks, I'll look at the file right away to see how you made it. I will update the version in the profile immediately. I don't think I have problems in modeling, sometimes I have doubts about the roads to follow, I hoped there was an automatic system to make the races (and I learned a new term not to make any figures). .

 

[MassiVonWeizen]

to a better analysis one realizes that it is not possible to make the race with an angle of deformity because this is not constant between greater section and minor section
In fact, there is an ellipse of 38x16 and at the end of 27x11; therefore, on the greater section, there is a difference of 5.5 (38-27/2) and on the smaller one of 2.5 (16-11/2) making evident that the corners of the two sections are different as seen from the image.

 

[Mito125]

I'm sorry, but today I couldn't find a moment to see the file, I didn't understand what you mean with a sform angle. Isn't the sweep solution okay?

 

[MassiVonWeizen]

Primary

a radial extrusion with a profile + strip angle

and I later

to use the strip angle you must first calculate it

you mentioned the idea of performing a normal extrusion by adding the deformed angle which is an option of the function.

I wanted to try to make it through a global variable to recall in the function I took over the model and therefore I realized that it was not a feasible method for the reason I described. the sform angle is often used in mold patterns or in those cases where a particular is modeled which will be made by fusion as in this case.
the function used however is the loft and does not sweep it because the latter does not allow to change the profile section.

I was just a supplementary post

 

[Mito125]

Thanks, I still confuse the two functions loft and sweep (confuse only the name, then use them without confusing them). Today I hope to see your model to understand how it looks.