Gearbox Maximum Torque

[Joe Johnson]

Originally Posted by Peter Johnson

But it's fun (and a good educational experience) to dig into the HOWs!

http://www.bostongear.com/pdf/gear_theory.pdf is a wonderful reference for gear theory. See page 6 of the PDF for the Lewis formula (Barth revision) for safe static stress on gear teeth, for example. Given the face width, diametral pitch, pitch diameter, pitch line velocity (or RPM), and material, the formulas and tables on that page will give you the max torque a gear can take (at least on the teeth).

Thanks for the reference.

I didn't mean to imply that we can't get into the HOWs a bit but I just wanted to be clear that ChiefDelphi.com is no substitute for an in depth engineering class.

And... ...Don't get me started on the Lewis formula! It is a good starting point but it is clearly too conservative for many many applications (including every FIRST robot I have ever encountered).

Bill Beatty and I agree (I can't find the thread but trust me, he does) on this point -- a simple beam bending stress calculation is a more appropriate estimate for FIRST gear teeth.

Joe J.