Compared with other forms of gear transmission, worm gear transmission has the following advantages and disadvantages.

1. Advantages:

(1) High single-stage speed ratio:

The single-stage speed ratio of circular gear transmission and bevel gear transmission is generally around 1/10, while the worm gear transmission with a speed ratio of 1/70-1/100 is easy to choose. Therefore, worm gear transmission reducers can achieve large speed ratios with smaller external dimensions The comparison between worm gear reducers and helical gear reducers with speed ratios of 1/5, 1/25, 1/70, and 1/150 is shown in Figure 8-2. Their transmission power is 30 horsepower and the input shaft speed is 1200 revolutions per minute.

(2) Transport and transit. T has low noise and vibration:

When circular gears and bevel gears are aligned, they mainly have rolling contact, while worm gears mainly have sliding contact, so there are fewer factors that generate noise and vibration. For this reason, worm gear reducers are commonly used to drive escalators, elevators, moving sidewalks, and machines that have been used to prevent pollution in recent years.

Use a worm gear reducer.

(3) Axes can be arranged vertically without intersecting with each other:

The arrangement of worm shaft and worm gear shaft can sometimes achieve both saving the installation area of the prime mover and the driven machine while being convenient and reasonable.

(4) Can prevent reversal:

When the lead angle of the worm gear is less than the friction angle, theoretically, the worm gear cannot be driven by the worm wheel, which means that a self-locking worm gear transmission device can be designed. However, in reality, the friction coefficient of the tooth surface changes from static friction coefficient to dynamic friction coefficient due to vibration and other reasons, so it sometimes rotates slowly and it is difficult to achieve complete self-locking.