| 摘要 |
PROBLEM TO BE SOLVED: To maintain hermetically sealing property of a steel drum shaped case for accommodating a transformer, and to maintain strength and rigidity of a steel-made disk by erecting a cable post fitting and other cylindrical members at predetermined positions on the thin plate of the steel-made disk so that the axis of the cylinder is orthogonal to the steel-made disk. SOLUTION: In a welding method, the lid of a steel drum shaped case for accommodating the transformer is formed of a ductile steel-made thin plate, a circular hole of the predetermined diameter is opened at the predetermined position on the thin plate of the steel-made disk, the circular hole is deep-drawn by a die to form an annular projection on the inner surface of a steel drum lid, and the entire circumference of an outer surface of one end of the cable post fitting and other cylindrical members is welded to the inner face of the annular projection. COPYRIGHT: (C)2007,JPO&INPIT
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