The manufacturing ways of worms are roughly divided among cutting, heat treated and ground after cutting and rolling. And for worm wheels, they are often roughly divided among cutting the teeth, cutting teeth after casting, and pearly whites cutting after the exterior rim is definitely cast around the guts of the blank.
As for the components for worm gears, for worms: structural carbon steel (S45C, etc.), structural alloy steel (SCM415, etc.), stainless and cast iron will be used; and for worm wheels: cast iron (FC200, etc.), non-ferrous metals such as phosphor bronze and specialty bronze (nickel bronze, aluminium bronze, etc.), engineering plastics such as MC Nylon, etc. As the combination of products for worms and worm tires influences the allowable plastic worm gear transmission force and lubrication strategies, the decision of mating resources requires careful consideration. Also, linked to the friction of the teeth, a harder materials for worm than worm steering wheel is generally used.
Ordinarily the lead angles of the proper and left tooth surface of a worm will be the same. Yet, in duplex worm gears, they are made to ensure that the tooth thickness of the worm alterations continually in the axial course so that by shifting the worm axially with shims, it becomes possible to change the backlash.
If a worm gear is used, a big speed lowering can be acquired in a concise space in comparison to using spur gears. Generally, the worm is employed to carefully turn the worm wheel. But when the lead angle is especially small, the worm wheel can not turn the worm and it is named its self locking feature. This can be used effectively in some applications but it can’t be called ideal preventative for reverse driving. (When the lead angle is certainly large, it is possible to switch the worm with the worm wheel.) In addition, there are many benefits to worm gears such as for example low noises and vibration, but as a result of the significant sliding at the tooth floors (sliding contact), the performance is certainly low. (For cylindrical worm gears, the general efficiency is approximately 30-90%.) Likewise, there are negatives such as for example they tend to have problems with tooth surface heating seizure.