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Manufacturing of Actuator Armature

As the armatures belong to the moving part of the EMVT, like the valves, their weight affects the Eigen frequency of the system, too. The aim is to reduce the overall moving mass as much as possible to achieve a high Eigen frequency. A high Eigen frequency means a short travelling time from the open to close position and vice versa. Such a fast system is necessary for proper operation of the engine at high rpm. The goal for the armatures is to reduce their weight from 0.77 kg down to 0.63 kg. In contrast to the valves a weight reduction by alternative materials is impossible, since only iron nickel and cobalt have the required magnetic properties. Weight reduction has to be achieved by an optimised design.

A solid silicon-iron is used as the armature plate to reduce eddy current losses since a lamination seems to be to fragile. A stem of valve steel is attached to the plate by friction welding. This manufacturing process is more cost effective and has a better rigidity than brazing. All necessary processes were developed and are well understood. The transfer of the sample production to mass production is meanwhile only a smaller step as similar technologies are applied for the production of valves.

Informations connexes

Reported by

TRW Automotive GmbH
Hannoversche Strasse 73
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