First, it has a relatively large transmission ratio and a very compact structure. If it is transmitting power, i=8~80; if it is transmitting motion, the maximum i can reach 1000.
Secondly, it can drive smoothly and the noise is very small. This is mainly because the meshing of the worm and worm gear teeth is continuous, and the number of meshing tooth pairs is relatively large, so the transmission is relatively smooth and the noise is relatively low.
Third, it can use self-locking performance. If the helix angle of the worm is not as large as the equivalent friction angle between the gears, the worm drive will start to self-lock. In other words, only the worm drives the worm gear, and the worm gear cannot drive the worm.
Fourth, worm transmission still has its own shortcomings. The most obvious one is that the transmission friction loss is relatively large and the efficiency is also very low. Usually the efficiency is only 0.7~0.8. If the worm drive also has a self-locking function, its efficiency will be below 0.5. Therefore, the worm drive is not suitable for transmitting high power and long-term continuous operation.
Fifth, another major disadvantage of worm drive is that it is relatively expensive. Sometimes in order to reduce its friction loss, the worm gear will be made of precious anti-friction material (bronze). This is certain. Increases its manufacturing cost to a certain extent.
So, from the above five aspects, we know that although worm drive has outstanding characteristics, its shortcomings are also obvious. From this aspect we can conclude that the worm drive device is suitable for machinery with large transmission ratio and low transmission power.