| 摘要 |
PROBLEM TO BE SOLVED: To provide a temperature-difference bending method for a metal tube which is executed by an adequate pusher thrust and is free of arm revolution. SOLUTION: A course on a fore end side of a metal tube 1 is regulated in an arc shape by a freely turnably arm 4, and the metal tube 1 is bent by executing the induction heating of a short section in the longitudinal direction in an annular shape by a heating device 3 while pushing the metal tube by a pusher 6 from a rear end side. Before the bending, when determining the values for setting the temperature range and the temperature related to an annularly heated section to the heating device 3, the target neutral axis θe is calculated from the required value of the wall thickness reduction ratio, the required value of the bending radius, and the shape value of the metal tube. When determining the set values of the temperature range and the temperature, the additional condition that a low-temperature range θt is limited to a back side T from the target neutral axis θe in addition to the condition of balance of forces. COPYRIGHT: (C)2010,JPO&INPIT
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