To prevent the buckling of a cylindrical body 2 when performing outward curling work by pressing the end parts in both side parts 2b, 2c in the axial direction with curling dies 5, 5 after forming the cylindrical body 2 composed of a drop part having a small outside diameter and both side parts having a large outside diameter by expanding a cylindrical base stock consisting of an aluminum alloy.
When performing the curling work, the outer periphery of the drop part of the cylindrical body 2 is restrained with a buckling preventing die 3a. Because the pressurizing force of axial compression with the curling dies is received with the buckling preventing die, the buckling deformation of the cylindrical body 2 is prevented. For this buckling preventing die 3a, a divided die which is arranged on the outer peripheral side of the cylindrical base stock at electromagnetic forming is used as it is.
SATO JUNICHI
MASUMOTO DAIGO
HONDE KATSUHIRO
DAIDO KOGYO KK
| JP2005095982A | 2005-04-14 | |||
| JP2003236637A | 2003-08-26 | |||
| JP2005052884A | 2005-03-03 | |||
| JP2004160542A | 2004-06-10 |
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