The manufacturing ways of worms are roughly divided among cutting, heat treated and ground after cutting and rolling. And for worm wheels, they could be roughly divided among cutting the teeth, cutting tooth after casting, and the teeth cutting after the outside rim is cast around the center of the blank.
As for the supplies for worm gears, for worms: structural carbon steel (S45C, etc.), structural alloy steel (SCM415, etc.), stainless and cast iron will be employed; and for worm tires: cast iron (FC200, etc.), non-ferrous metals such as for example phosphor bronze and specialized bronze (nickel bronze, aluminum bronze, etc.), engineering plastics such as MC Nylon, etc. Because the combination of products for worms and worm tires affects the allowable transmission power and lubrication methods, the decision of mating materials requires consideration. Also, linked to the friction of teeth, a harder material for worm than worm wheel is generally used.
Ordinarily the lead angles of the right and remaining tooth surface of a worm will be the same. Yet, in duplex worm gears, they are created so that the tooth thickness of the worm adjustments continually in the axial route to ensure that by shifting the worm axially with shims, it becomes possible to change the backlash.
If a worm gear is used, a big speed decrease can be obtained in a compact space in comparison to using spur gears. Generally, the worm is employed to turn the worm steering wheel. But when the lead angle is particularly small, the worm wheel cannot turn the worm and it is known as its self locking feature. This can be used effectively in some applications but it can not be called ideal plastic worm gear preventative for invert driving. (When the lead angle is certainly large, you’ll be able to flip the worm with the worm steering wheel.) In addition, there are many advantages to worm gears such as for example low noises and vibration, but as a result of the huge sliding at the tooth surfaces (sliding contact), the performance is normally low. (For cylindrical worm gears, the general efficiency is approximately 30-90%.) As well, there are disadvantages such as for example they tend to have problems with tooth surface temperature seizure.