The manufacturing methods of worms are roughly divided among cutting, heat treated and ground after cutting and rolling. And for worm wheels, they can be roughly divided among cutting teeth, cutting teeth after casting, and pearly whites cutting after the outside rim is cast around the center of the blank.
As for the elements for worm gears, for worms: structural carbon metal (S45C, etc.), structural alloy metal (SCM415, etc.), stainless steel and cast iron happen to be applied; and for worm wheels: cast iron (FC200, etc.), nonferrous metals such as phosphor bronze and specialized bronze (nickel bronze, aluminium bronze, etc.), engineering plastics such as MC Nylon, etc. As the combination of products for worms and worm wheels impacts the allowable transmission power and lubrication methods, the decision of mating supplies requires consideration. Also, related to the friction of pearly whites, a harder materials for worm than worm steering wheel is generally used.
Ordinarily the business lead angles of the proper and left tooth surface of a worm will be the same. Yet, in duplex worm gears, they are made so that the tooth thickness of the worm improvements consistently in the axial direction in order that by shifting the worm axially with shims, it turns into possible to adapt the backlash.
If a worm gear is used, a huge speed decrease can be acquired in a concise space in comparison to using spur gears. Generally, the worm is employed to turn the worm wheel. But when the lead position is particularly small, the worm wheel can not turn the worm in fact it is referred to as its self locking feature. This can be utilized effectively in a few applications but it can not be called excellent preventative for reverse driving. (When the lead angle is definitely large, it is possible to switch the worm with the worm wheel.) In addition, there are many advantages to worm gears such as for example low noise and vibration, but because of the huge sliding at the tooth surfaces (sliding contact), the effectiveness is usually low. (For cylindrical worm gears, the overall efficiency is about 30-90%.) As well, there are cons such as they tend to suffer from tooth surface high gigi cacing plastik temperature seizure.