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Technical Papers
HMP Group
Mono Tubular Rotor Shafts, produced by Rotary Swaging
In automotive engineering, a fun- damental change will take place in the coming years. Digitiza- tion, networking with its impact on safety systems, autonomous driving and new drive architec- tures will lead to the replacement of established components and the demand for new ones. It can be expected that the number of installed components will drop signi cantly as well as the pro-
portion of steel components. However, the remaining com- ponents typically ful ll several functions, are weight-optimized and often have the closest man- ufacturing tolerances. Cold metal forming will be faced to major challenges.
In the drive architecture, there is much evidence that the electric drive will prevail sooner or later. In the electric motors for this
application, rotor shafts made of steel are used. These components are exposed to high dynamic and thermal stress. Typically for new-generation components, rotor shafts ful ll several func- tions:
• Torque transmission • Cooling
• Sensor placement
• Rotor package t
HMP offers the possibility to realize these shafts weight-op- timized. From our point of view, a mono tubular solution is to be favored. Multi-part, assembled solutions are subject to the risk that the joints could adversely affect the component strength.
Starting from a xed to length tube, a preform is rst produced by rotary swaging. This is con- verted into the nished state by soft turning, axial pressforming, heat treatment and hard working.
Rotary Swaging, a powerful forming process
Rotary swaging is an incremen- tal metal forming process for the reduction of cross-sections of bars, tubes and wires. Sets of two, three, four or six dies perform small, high-frequency, simulta- neous radial movements (oscilla- tions). With every stroke of the die, a part of the workpiece is formed. Die movement is gener- ated by means of cams. The kine- matics are equivalent to those of a planetary gear. This is completely accessible, which makes it easy to carry out any maintenance work.
ITAtube Journal No2/July 2018
30