Do worm gear drives typically require mechanisms to prevent reverse rotation?

Worm gear drives are known for their unique design that provides a high gear reduction in a compact form factor. One significant characteristic of worm gears is that they inherently prevent reverse rotation. This is due to the geometry of the worm and the worm wheel; the angle and shape of the teeth are such that the worm can turn the gear, but if you attempt to turn the gear in the opposite direction, it cannot effectively drive the worm back.

This self-locking feature means that additional mechanisms to prevent reverse rotation, such as brakes or locking devices, are generally unnecessary in systems utilizing worm gear drives. This makes worm gear drives particularly useful in applications where maintaining position under load is crucial, as they can hold their position without back-driving.

In contrast, other types of gear drives may not possess this feature and would require separate mechanisms to ensure they do not rotate in the opposite direction under certain conditions, such as during power loss or when subjected to external forces.