| 摘要 |
PROBLEM TO BE SOLVED: To provide a manufacturing method for a metallic bent tube, by which, when manufacturing a metallic bent tube that is joined to an object to be joined via an O-ring, an O-ring groove is formed and the rising height from the object can be made lower by preventing roll over caused by press work at the end part of the tube, even in the case that a bent part with an extremely small bend radius is formed contiguously to the end part of a straight tube. SOLUTION: A bent part 10 with an extremely small bend radius is formed by bending a portion contiguous to the end part of a straight tube. Then, the end part is slantwise cut so that a cut end part 19', where the side connecting to an outside bent part 10b of the bent part 10 is projected further than the side connecting to an inside bent part 10a, is formed. Next, a cylindrical expanded tube part 21 with an approximately constant wall thickness is formed by press-forming the cut end part 19' in the tube axial direction of the cut end part 19'. Finally, an O-ring groove is formed by applying roll forming to the outer peripheral face of the expanded tube part 21. COPYRIGHT: (C)2006,JPO&NCIPI
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