| 摘要 |
PROBLEM TO BE SOLVED: To provide a pipe bending device with a simple device constitution and a pipe bending method where, in the bending of a pipe with a relatively large bend radius, the reduction of the wall thickness in the outside of a bend is suppressed and the buckling at the inside of the bend is not generated without using tools such as a core bar and a buckling preventor. SOLUTION: The device comprises: a bending die 1 having grooves 1U, 3U having shape corresponding to bending shape; a pressure die 3; a clamp 2; a pressurizing means 8; and a tension means 13. The pressurizing means 8 pressurizes the intersection between the straight line L1 obtained by shifting a straight line L0 passing through the abutted point of the pipe p in the bending die 1 and the rotary center o by a distanceδ(0 to D) to the inlet side of the pipe with the pressure die to the direction of the straight line L1. The tension means 13 applies tension to the pipe p in the pipe axis direction. By making the total of the circumferential lengths of the grooves 1U, 3U shorter than the circumferential length of the pipe, so as to apply drawing to the pipe, and also, performing the bending as tension is applied to the direction of the pipe axis, when a thin pipe is subjected to bending, so as to be a relatively large bend radius, the generation of buckling at the inside of the bend can be effectively suppressed. COPYRIGHT: (C)2007,JPO&INPIT
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