The shaft-mounted worm gear reducer can obtain a large transmission ratio, and its load carrying capacity is much higher than the staggered shaft helical gear mechanism. The worm drive is equivalent to a helical drive and is a multi-tooth meshing drive. . When the lead angle of the worm is smaller than the equivalent friction angle between the teeth of the meshing gear, the mechanism is self-locking and can achieve reverse self-locking, that is, the worm can only be driven by the worm, but not by the worm. Such as the self-locking worm mechanism used in its heavy machinery, its reverse self-locking can play a safety protection role, transmission efficiency is low, wear is more serious. When the worm gear is engaged and driven, the relative sliding speed between the teeth of the meshing gear is large, so the friction loss is large and the efficiency is low. On the other hand, the relative sliding speed ambassador has serious wear on the tooth surface and severe heat generation. In order to dissipate heat and reduce wear, more expensive materials with good friction reduction and wear resistance and good lubrication devices are often used, so the cost is higher. .