What is a Worm-Gear Reducer?

A worm-gear reducer is a reduction gear box type which consists of a helical output gear and a worm input gear. This type of reduction gearbox features a right angle output orientation and the highest reduction values in the smallest package of all gearbox types. The worm-gear reducer offers several other distinct advantages over bevel and helical gearboxes, which include lower costs and higher shock-loading tolerances. They also deliver high output torque values in relation to their sizes. This type of reduction gearbox is, however, generally only usable in applications featuring low-input power ratings.

Reduction gearboxes generally take a high speed, low-torque input and produce a low-speed output with a higher-torque value. The worm-gear reducer is one of the most useful of these, offering several notable advantages over other types. The first of these is space-saving, as this type is one of the sleekest reduction gearboxes available due to the small diameter of its output gear. They also offer one of the lowest reduction values and highest output torque ratios relative to the gearbox size. Worm gear reducers also exhibit outstanding shock-loading capabilities and low initial costs.

The worm-gear reducer consists of an input shaft which drives a fairly large worm gear. This gear, in turn, drives a helical gear-equipped output shaft at right angles to the drive orientation. Worm gears offer excellent mechanical advantage values for a relatively small gear, which allows these reducers to deliver very good reduction and torque values in a diminutive package. The design of worm gear leads or teeth also lends this type of gearbox good shock-loading qualities.

The only real disadvantage of the worm-gear reducer is the fact that they require low horsepower ratings in relation to the gearbox size. This tends to lead to slightly lower long-term efficiency ratings for these reducers when compared to high-input power types such as bevel and helical gear examples. This restriction is, however, more often than not offset by the small sizes of the reducers and their low costs. One characteristic of worm-gear trains which is often unreasonably relied on is their tendency to lock up if the drive direction is reversed. This is sometimes seen as a “self-locking” or braking feature, but is subject to too many outside influences to be considered reliable as a braking mechanism.