| 摘要 |
PROBLEM TO BE SOLVED: To provide a hot bending method for a metal tube, which can eliminate conventional constraint regarding a bending radius ratio by preventing stress imbalance accompanying the bending process from leading to irregular deformation, and a device therefor. SOLUTION: The front end of a metal tube 1 to be bent is gripped by a front clamping unit 15 of a bending arm 14 which turns with a central axis 12 as the center. The rear end of the metal tube 1 is gripped by a rear clamping unit 21 of a propulsion unit 18 placed at the rear of a heating/cooling apparatus 16. In the bending process, the metal tube 1 heated and cooled by the heating/cooling apparatus 16 is advanced by the propulsion unit 18 and is bent by the turn of the bending arm 14, with the metal tube 1 being clamped by the clamping units 15 and 21 with a clamping margin which produces elastic diameter shrinkage, whereby the metal tube 1 is bent in a state of lessening flattening stress generated in a plane intersecting with the locus of the center of the metal tube 1 at right angles, with the application of bending moment. COPYRIGHT: (C)2007,JPO&INPIT
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