The manufacturing methods of worms are roughly divided among cutting, heat treated and ground after cutting and rolling. And for worm wheels, they may be roughly divided among cutting teeth, cutting tooth after casting, and the teeth cutting after the outside rim is usually cast around the guts of the blank.
As for the products for worm gears, for worms: structural carbon steel (S45C, etc.), structural alloy metal (SCM415, etc.), stainless and cast iron will be utilized; and for worm tires: cast iron (FC200, etc.), non-ferrous metals such as phosphor bronze and specialized bronze (nickel bronze, metal bronze, etc.), engineering plastics such as for example MC Nylon, etc. As the combination of components for worms and worm wheels impacts the allowable transmission induce and lubrication methods, the decision of mating materials requires careful consideration. Also, related to the friction of tooth, a harder materials for worm than worm steering wheel is generally used.
Ordinarily the lead angles of the right and remaining tooth surface of a worm will be the same. However in duplex worm gears, they are made so that the tooth thickness of the worm improvements constantly in the axial course in order that by shifting the worm axially with shims, it becomes possible to adapt the backlash.
If a worm equipment is used, a huge speed decrease can be obtained in a compact space in comparison to using spur gears. Generally, the worm is utilized to turn the worm wheel. But when the lead angle is especially small, the worm wheel can not turn the worm in fact it is known as its self locking characteristic. This can be utilized effectively in a few applications but it can’t be called best preventative for reverse plastic worm gear driving. (When the business lead angle can be large, it is possible to flip the worm with the worm steering wheel.) Furthermore, there are many benefits to worm gears such as low noise and vibration, but due to the significant sliding at the tooth surfaces (sliding contact), the performance is low. (For cylindrical worm gears, the general efficiency is about 30-90%.) Also, there are cons such as for example they tend to suffer from tooth surface warmth seizure.