The characteristics of the worm gear mechanism

Worm gear mechanisms are often used to transmit motion and power between two staggered shafts. The worm wheel and the worm are equivalent to the gear and the rack in their mid-plane, and the worm is similar in shape to the screw.

The characteristics of the worm gear mechanism:

1. A large transmission ratio can be obtained, which is more compact than the staggered shaft helical gear mechanism.

2. The meshing tooth surfaces of the two wheels are in line contact, and its bearing capacity is much higher than that of the staggered shaft helical gear mechanism.

3. The worm drive is equivalent to a screw drive, which is a multi-tooth meshing drive, so the drive is stable and the noise is small.

4. It is self-locking. When the lead angle of the worm is less than the equivalent friction angle between the meshing gear teeth, the mechanism has self-locking properties and can achieve reverse self-locking, that is, only the worm can drive the worm gear, but the worm cannot be driven by the worm gear. For example, the self-locking worm mechanism used in hoisting machinery, its reverse self-locking can play a role in safety protection.

5. The transmission efficiency is low and the wear is more serious. When the worm gear is engaged in the 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 causes serious wear and heat generation of the tooth surface. In order to dissipate heat and reduce wear, more expensive materials with good anti-friction and anti-wear properties and good lubricating devices are often used, so the cost is high. .

6. The axial force of the worm is large.