A worm gear set actually looks a lot like it sounds — there's a worm that drives a gear. The worm — a shaft with a spiral thread — engages with and drives the gear — a toothed wheel. The worm screw and worm wheel are aligned at a 90-degree angle, forming the simplest kind of right angle gearbox. In fact, a worm gear was one of the original six simple machines. No matter how simple, though, the worm gear is an effective, time-honored way to manage power and torque.
Uses for Worm Gears
Worm drives create a compact means to substantially decrease speed and increase torque.A worm gear can have a massive reduction ratio with little effort — by simply adding more circumference to the wheel. That technique can either greatly increase the torque, or greatly reduce the speed. By comparison, it would take multiple reductions of a conventional gear set to achieve the same results — so worm gears have fewer moving parts and fewer places for failure.