| 摘要 |
PCT No. PCT/JP96/02214 Sec. 371 Date Mar. 17, 1998 Sec. 102(e) Date Mar. 17, 1998 PCT Filed Aug. 5, 1996 PCT Pub. No. WO98/05447 PCT Pub. Date Feb. 12, 1998A method of forming a cylindrical portion of a cylindrical member made of a sheet metal according to the present invention relates to steps of rotating a cylindrical member fitted into rotating dies with the rotating dies while pressing the cylindrical portion against the rotating dies by the forming roller. In the present invention, a pressed portion of the cylindrical portion, pressed by a forming roller is moved from an opening end side of the cylindrical portion to a root portion side thereof according to each phase. For example, the pressed portion of the cylindrical portion pressed by the forming roller includes two sections, namely a first phase-pressed portion positioned on the opening end side of the cylindrical portion and a second phase-pressed portion positioned on the root portion side thereof. Previously, the first phase-pressed portion was pressed by the forming roller to be thinned and extended, and after that, the second phase-pressed portion is pressed by the forming roller to be thinned and extended, so that the cylindrical portion obtained by the above steps is not widened toward the end.
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