New technology for manufacturing preforms of part «CONICAL PINION SHAFT»

The part «conical pinion shaft» is widely used in the design of speed reducers.

Figure 1 - Pinion shaft

A specific feature in the design of «CONICAL PINION SHAFT» is a significant difference between the diameters of end and cone. The diameter of end part is usually 3…5 times smaller than the maximum diameter.

The most common way of manufacturing preforms for «conical pinion shaft» is longitudinal forging. High-powered equipment is required for application of this method. For example, the most popular transmission shafts for cars are manufactured by longitudinal forging on the presses with the force of 6000...8000 tons.

Beltechnologia&M JSC has developed a new method of manufacturing conical transmission shafts by means of reverse cross-wedge rolling with extrusion and edging.

The dies for reverse cross-wedge rolling are designed in such a manner that their inclined facets close in from the beginning of the die to its end. This way the inclined facets act on the billet in the counter axial direction.

During the process of end part forming via reverse rolling the metal is flowing towards the movement direction of the inclined facets of the dies, where the effect of material extrusion from the deformation zone towards the end of the billet is realized. The material gets thicker while flowing through the core of the billet.

The tension in the core is characterized by two compressing stresses and one tensile stress, which considerably lowers the probability of Mannesmann effect manifestation.

Figure 2 - Stress condition diagram

The presence of compressive counter-stresses, which make breaking of the rod during rolling impossible, is considered an important advantage of the reverse cross-wedge rolling. Significantly higher reduction under the rod breaking condition can be achieved with reverse cross-wedge rolling, compared to the direct cross-wedge rolling. The process of reverse cross-wedge rolling was simulated at a scale of 1:4.7. On the part pinion shaft.

Figure 3 - Preliminary drawing of the preform and pinion shaft

Figure 4 - Isometric view of the dies for reverse cross-wedge rolling of the part "PINION SHAFT"

As a result, the process was proven to be industrially applicable. The following figures were achieved during the simulation: - Material utilization ratio - 80% - Edging ratio — 1,2 . - Reduction ratio - 3 It was established that a preform for the part «pinion shaft» with cone diameter of up to 250 mm and end diameter of 50 mm can be rolled on the SP5000 machine with drive force of 75 tons a 10…20 sec. per piece rate. Beltechnologia&M JSC is ready to receive orders for equipment and technology.