Worm-gear. Principle of operation

The worm gear provides the conversion of motion according to the principle of the second pair or the inclined plane. In this case, diameters of long and initial cylinders are distinguished. The pole of the link is the point of tangency of the initial cylinders.

The worm gear includes a screw (which is called a worm) and a wheel. The angle of the cross between the shafts of the wheel and the screw can be different. However, as a rule, it is equal to ninety degrees. The worm gear has the advantage over the toothed-helical gear. It manifests itself in the fact that the initial contact of the links is not carried out at a point, but along a line. The rim of the wheel, which includes the worm gear, has a concave shape. The screw thread can be left or right, multi-threaded or single-threaded.

Worms are distinguished by the shape of the surface where the thread is formed. In accordance with this, there are globoidal and cylindrical. In view of the shape of the profile, curvilinear and rectilinear types are distinguished. The most common are cylindrical worms. In parts with a straight profile in the cross section, the turns are delineated by an archimedean spiral. Therefore they are called Archimedean worms. They are similar to threaded screws with trapezoidal threads. They can be cut on a thread-milling or conventional lathe.

Practice has shown that the worm gear motor differs in its increased capacity, provided that the hardness of the thread is increased. In recent years, more and more widespread high-strength polished parts. For the processing of products, special grinding wheels with a shaped profile are used. However, this complicates the processing and lowers the accuracy in manufacturing. In this regard, the production of archimedean worms is carried out with unpolished coils. For the processed high-hardness elements, involute parts having a corresponding profile in the end section are used. The main advantage of these worms is the ability to grind the turns with the help of the flat side of the circle. But with this special machines are necessary.

The worm gear motor NMRV is a special electric motor. Advantages of the detail in a compact size, quiet and smooth operation. Due to the unified connecting dimensions , this gearbox can be used instead of the units of other manufacturers. Due to the fact that the output shaft and the multi-purpose housing, which has been developed to a right angle, are somewhat modernized, the part can be placed in places where it is impossible to establish models with a coaxial shaft arrangement. Thanks to modern injection molding technology, advanced models of aggregates are being manufactured today.

The worm wheel is cut with suitable milling cutters. They are identical to the screws. However, the cutters have an outer diameter and the cutting edges are twice the size of the radial clearance. When cutting the workpiece, the wheel and the cutter reciprocate in the same way as the worm gear.