Worm Gear Gearbox

[Andy Baker]

Originally Posted by Max Lobovsky

What are "starts"? The number of threads? I thought the number of threads was equivalent to the number of teeth so more threads is less reduction (and i would assume more efficient)

Here is a product manual from Martin Spocket and Gear. On page 69 of this link, the worm gear has 1 start (a single thread). On page 70, it shows a worm gear with 2 starts (double thread). On page 71, a worm gear with 4 starts (quadruple thread) is shown.

On the shoulder joint of our elbow for last year's TechnoKat robot, we used a 40 tooth worm gear (Martin # W1240) and a single threaded worm gear (Martin # WG12).

This design worked well, except when the arm would bounce or hit something. The teeth on the worm gear would shear. If we ever need to use this sort gearing again for an arm, we will need to do two things: 1. use a gear with larger teeth 2. provide more of a counterbalance for this same sort of joint

Andy B.