| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of manufacturing a bent hollow pipe by which a good pipe can be formed even when forming a three-dimensionally bent pipe. SOLUTION: This method is a method of manufacturing the bent hollow pipe which is bent and stretched three-dimensionally by butting two side sides of a material W to be worked by performing stepwise press working of a material W to be worked which is a plate with a plurality of forming dies and has a stage where extended parts 15 which are formed on both sides across an extruded part 13 of the material W to be worked which are receded each other while being extruded in the direction of the outside of the surface with the material W to be worked, also forming the extruded part 13 where is bent and stretched in a plane and collar parts 16 which are bent in the pressing direction are formed at the noses of the extended parts 15 by the press working, both the collar parts 16 are formed in the directions in which the collar parts 16 are faced each other by bending the bent parts 17 between the extended parts 15 and the collar parts 16 in the opposite direction as maintaining the bending between the extended parts 15 and the collar parts 16 and a stage where the noses of the collar parts 16 are butted. COPYRIGHT: (C)2008,JPO&INPIT
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