Self-lockingonly occurs with worm gears. In a self-locking gear unit, the output shaft cannot be moved by a torque applied to this shaft. It behaves like a brake. A vivid example of a self-locking gear is a wiper motor for windscreens. When the motor is switched off, the wiper stops in place and cannot be moved in any direction.
A worm gear becomes self-locking when its degree of efficiency becomes less than 0.5. In such cases, we speak of static self-locking if the drive exhibits this behavior when idle. This static self-locking effect is indicated in the list of gears on our website. The friction coefficient at the point of contact can be affected through regular operation or occurring vibrations and the degree of efficiency can be improved. If a drive is self-locking even in this state, this is called dynamic self-locking.
Planetary gears that have a very high reduction ratio exhibit a similar behavior. Their output shaft cannot be moved seemingly. However, this is due to the high frictional torque in the gearbox. If the torque is increased, any planetary gear can be operated in reverse. Self-locking worm gears however cannot be operated in reverse, regardless of the force applied.
Our self-locking portfolio: