| 摘要 |
PROBLEM TO BE SOLVED: To provide a method and an apparatus for manufacturing a spiral pipe, by which method and apparatus, the shape of the spiral portion is formed on the outer portion of a blank pipe material without being affected by the variation of a twisting torque due to the dispersion of the thickness of the blank pipe and the run-out due to the rotation of the blank pipe in manufacturing the spiral pipe. SOLUTION: In the method for manufacturing the spiral pipe, a plurality of recessed portions is formed on the peripheral surface of a smooth pipe material 5 as origins, and then the periphery of the pipe material is formed into a spiral corrugated shape by turning the portions separated from the recessed portions by a required distance so as to twist the portions. A forming member 4 formed beforehand according to the corrugation to be achieved is brought into pressure contact with the recessed portions to be the origins. After that, the forming member is moved along the spiral recessed portion interlocking with the turning motion. COPYRIGHT: (C)2008,JPO&INPIT
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