Articles on: Learning & FAQ

Self-locking of Worm Gear

The self-locking worm gear is a mechanical transmission method, which is characterized by preventing reverse rotation and maintaining the same position even when the power supply is stopped.

The principle of worm gear self-locking is that the friction between the slope of the worm and the tooth surface of the worm wheel makes the worm wheel unable to rotate in reverse after the power supply is stopped.

When the worm rotates, there will be friction between the tooth surface of the worm wheel and the slope of the worm, which will make the worm wheel unable to rotate freely. When the lead angle of the worm is smaller than the equivalent friction angle between the teeth of the meshing gear, the mechanism has Self-locking, reverse self-locking can be realized, that is, only the worm can drive the worm wheel, but the worm wheel cannot drive the worm.

In STEPPERONLINE products, generally the worm gear box with a speed ratio above 40:1 has the self-locking function.

The self-locking of the worm gear drive can replace the function of the brake to a certain extent, but in the occasions that require high precision and high safety, other safety mechanisms such as brakes are required to ensure the safety of the equipment. Because the self-locking of worm gear and worm drive can only play a role when the load is reversed, but it has no self-locking effect when it is moving forward. Therefore, in the occasion where safety control is required, it is necessary to use other safety mechanisms such as brakes to ensure the safety of the equipment.

Updated on: 02/08/2023

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