A worm gear is a type of gear system that consists of a worm (also known as a screw) and a gear wheel (also known as a worm wheel). The worm is a cylindrical shaft with a helical thread that meshes with the teeth of the gear wheel.

When the worm rotates, it drives the gear wheel, which rotates at a right angle to the worm. This results in a compact and efficient gear system that can achieve high gear ratios, making it useful in applications where space is limited, and high torque is required.

Worm gears are commonly used in machinery and mechanical devices such as lifting equipment, conveyor systems, and automobile steering mechanisms. They are also used in power transmission systems, where they are employed to transmit power between two shafts that are perpendicular to each other. One of the key advantages of worm gears is that they provide a high degree of mechanical advantage, which makes them well-suited to applications requiring heavy loads or precise motion control.