Minor glitches with non-circular (elliptical) gears

[Daniel B]

Hi,
I was just playing around and noticed two things that don't look right on the elliptica l gear generatio n.

The first is REALLY minor - like who cares - but I notice these things so I though you should know: the wheel teeth number is off by a factor of two compared to how many teeth are actually generated . So if you ask for 9 teeth, you get 18. Another oddity here is that the program restricts the entry to odd numbers. I noticed this because I was actually aiming for 36 teeth for a minute, and finally realized that I'd really need to ask for 18, and the closest I could get would be 17 or 19 giving me 34 or 38 actual teeth.

The second is that in super-close-up rotation, I noticed that at least on the screen, there's a slight overlap that happens once in a while. I'm attaching a screen-shot to illustrat e this.

I'm still really loving this program - just thought someone should know!

Daniel

[ArtF]

Hi Daniel:

  Non-circulalars are kinda special in the way they work. Firstly, the number of teeth is based on the order#1 gear the
gear is generated from. So if generatin g a Order#2 gear, there will be twice as many teeth. Mathmatic ally, an elliptica l gear with 10 teeth
but of order 3 is a gear with 30 teeth. The way they mesh requires special attention to the pressure angle, a round gear can have a
specified pressure angle and follow it, but an elliptica l gears pressure angle changes as it rotates, so its important to look at the
gear closely to make sure there is no overlap ( or as little as possible) by lowering the pressure angle requireme nt so that the overlaps
don't occur.
  In the next developme nt phase Ill be looking into new methods that are not as sensitive to such things, but elliptica ls presently
have those type of limitatio ns. Thankls for the comments though, proves your paying attention .

Art