A worm reducer is one of the least expensive and most compact gear reducers, used to increase torque while slowing output speed. Worm gears are used in a wide range of applications. They have a low initial cost and offer high ratios while also being able to tolerate shock loads better than helical gear reducers.
A Worm Reducer Overview
The basic components of a worm reducer are a worm, a pinion and a worm wheel. The worm is a screw that turns in the direction of the input shaft and pushes the teeth on the worm wheel when power is applied to it. The worm wheel has a tooth profile that is longer than the worm, which allows it to be more wear resistant. The worm and worm wheel work together to rotate the pinion, which is used to apply torque.
Unlike spur and bevel gears, a worm drive has no output-to-input reversibility. This is because the worm and worm wheel are in contact and, due to the friction between them, can not be driven backwards. This is especially important in hoisting operations, where a reversed direction of transmission may be dangerous or cause damage to the equipment.
Another disadvantage of a worm drive is its low performance. This is primarily because of its high friction and accompanying axial stresses, which can lead to wear that can affect the way the drive operates and the precision with which it can be controlled.
Some worm drives are self-locking, which is useful in situations in which the input and output cannot be switched when needed. This is usually the case in automotive steering systems, as well as some rotary blowers and wind governors that have single-start worms.
The lubrication used in a worm gear is typically mineral-based industrial extreme pressure (EP) type of lubricants. These oils are formulated with additives to prevent metals from wearing down and provide excellent frictional characteristics for the gear tooth surfaces.
Because worm gears have sliding contact, the use of a lubricant with a high viscosity is critical to prevent the worm from touching the worm wheel and causing damage. Most worm gear lubricants are designed to have a maximum viscosity of about 2,000.
This is because worm gears have a large contact surface area and a comparatively small number of teeth. As the worm moves across the worm wheel, it slowly wears away the lubricant layer that protects the worm surface from scratching the metal of the worm wheel. Once this lubricant is gone, the worm will continue to grind its way down the wheel tooth until it is no longer able to pick up lubricant and begin the process again on the next revolution.
Worm reducers can be made with a wide range of materials, including aluminum, cast iron and stainless steel. WorldWide Electric offers a variety of worm gear reducers in both metric and imperial sizes, with ratios from 25:1 to 900:1. These worm reducers are in stock and ready to ship to your location. If you are looking for more information about worm gears or want to know how to select an appropriate worm reducer for your application, contact us today!