PURPOSE: To satisfactorily remove a binder at a degreasing process by a method wherein a plurality of concentric round coils are installed on one plane of a transformer core formed by injection-molding a mixture of a sintering ferrite powder and the binder and a plurality of pin gates are formed on its opposite face.
CONSTITUTION: A plate type rotary transformer core 1 where ring-shaped grooves 2 have been formed on one plane is formed by an injection molding operation; gate parts 4 of pin gates used as gates at the injection molding operation are arranged on a face 5 opposite to the plane where the ring-shaped grooves 2 are formed, and are arranged in the central part of elevated planes 3. At a degreasing process after the injection molding operation, the binder in the core can be removed holding up the core by parts of the elevated planes 3 where the pin gates have been installed. It is possible to prevent a crack and a break.
IKEMOTO OSAMU
TANAKA KATSUNORI
BABASAKI YASUNORI
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