The worm drive is equivalent to a screw drive and is a multi-tooth meshing drive, so the transmission is smooth and the noise is small.
It has self-locking properties. When the lead angle of the worm is less than the equivalent friction angle between the meshing gear teeth, the mechanism is self-locking and can achieve reverse self-locking, that is, the worm can only drive the worm gear, but not the worm gear. For example, the self-locking worm mechanism used in other heavy machinery, its reverse self-locking can play a role in safety protection
The transmission efficiency is low and the wear is serious. When the worm gear is meshed for transmission, the relative sliding speed between the meshing gear teeth is large, so the friction loss is large and the efficiency is low. On the other hand, the relative sliding speed increases the tooth surface wear and heat seriously. In order to dissipate heat and reduce wear, more expensive materials with good friction reduction and anti-wear properties and good lubrication devices are often used, so the cost is high.