| 摘要 |
PURPOSE:To enhance the circular degree of a frame and improve radiating property, pressing a cylindrical main frame unit formed with a plate member being formed round, from outside, and by pressure-shaping the frame unit from the inner diameter side at a specified dimension after radiation fins are welded on the outer peripheral surface. CONSTITUTION:First, a specified plate member 1 is made round and formed in a roughly cylindrical shape, and the butted end surfaces are welded to form a cylindrical main frame unit 2. Then, on the outer diameter side of the main frame unit 2, metallic molds 23 with the inner diameter section formed on the cylindrical surface of desired dimension are arranged and are pressed from the outer diameter side, and the main frame unit 2 is cylindrically shaped. After that, on the outer peripheral surface of the main frame unit 2, radiation fins 11 are welded. Finally, inside the main frame unit 2, extension clicks 3 are inserted and pressed from inside to enhance the roundness degree of the main unit 2. As a result, contacting property between the frame unit 2 and a core 6 is improved, thereby heat radiating characteristic is improved.
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