The primary benefit for worm gears is their ability to provide high reduction ratios and correspondingly high torque multiplication. They can even be used as speed reducers in low- to medium-rate applications. And, because their decrease ratio is founded on the number of gear teeth by itself, they are smaller sized than other types of gears. Like fine-pitch business lead screws, worm gears are typically self-locking, which makes them well suited for hoisting and lifting applications.

Although the sliding contact decreases efficiency, it provides incredibly quiet operation. (The usage of dissimilar metals for the worm and gear also plays a part in quiet procedure.) This makes worm gears suited to use where sound should be minimized, such as in elevators. In addition, the application of a softer material for the gear means that it could absorb shock loads, like those experienced in serious equipment or crushing machines.

The meshing of the worm and the apparatus is an assortment of sliding and rolling actions, but sliding contact dominates at high reduction ratios. This sliding actions causes friction and high temperature, which limits the productivity of worm gears to 30 to 50 percent. In order to minimize friction (and therefore, heat), the worm and gear are constructed with dissimilar metals – for instance, the worm could be made of hardened steel and the gear made of bronze or aluminum.

Such as a ball screw, the worm in a worm gear may have a single start or multiple starts – and therefore there are multiple threads, or helicies, on the worm. For a single-start worm, each total flip (360 degrees) of the worm increases the gear by one tooth. Therefore a gear with 24 teeth provides a gear reduced amount of 24:1. For a multi-begin worm, the apparatus reduction equals the number of teeth on the gear, divided by the number of begins on the worm. (That is different from almost every other types of gears, where the gear reduction can be a function of the diameters of the two components.)

Worm Gear Shaft is a trend that is gradually growing.