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 teeth, cutting pearly whites after casting, and the teeth cutting after the exterior rim is certainly cast around the guts of the blank.
As for the materials for worm gears, for worms: structural carbon metal (S45C, etc.), structural alloy steel (SCM415, etc.), stainless and cast iron are utilized; and for worm tires: cast iron (FC200, etc.), non-ferrous metals such as for example phosphor bronze and specialty bronze (nickel bronze, aluminum bronze, etc.), engineering plastics such as MC Nylon, etc. Because the combination of components for worms and worm tires affects the allowable transmission pressure and lubrication methods, the choice of mating products requires careful consideration. Also, related to the friction of teeth, a harder material for worm than worm wheel is generally used.
Ordinarily the lead angles of the right and still left tooth surface of a worm will be the same. Yet, in plastic worm gear duplex worm gears, they are created in order that the tooth thickness of the worm adjustments continually in the axial course in order that by shifting the worm axially with shims, it becomes possible to change the backlash.
If a worm equipment is used, a sizable speed lowering can be obtained in a concise space compared to using spur gears. Generally, the worm is used to turn the worm wheel. However when the lead angle is particularly small, the worm wheel can not turn the worm and it is known as its self locking characteristic. This can be utilised effectively in some applications but it can not be called perfect preventative for reverse driving. (When the business lead angle is certainly large, it is possible to turn the worm with the worm steering wheel.) Furthermore, there are many benefits to worm gears such as low noises and vibration, but as a result of the large sliding at the tooth areas (sliding contact), the proficiency is normally low. (For cylindrical worm gears, the general efficiency is approximately 30-90%.) Also, there are negatives such as they tend to have problems with tooth surface temperature seizure.