| 摘要 |
PROBLEM TO BE SOLVED: To provide the manufacturing method by which the fin tube with bent parts bent to the side formed on the periphery of the fin, can be efficiently produced continuously. SOLUTION: While rotating the tube 57 at a constant speed and feeding it in the axial direction, after winding the band steel shape fin 58 in helical form on the periphery of the tube 57, they are welded. And, after that, a jig 55 is made to come into contact with the fin 58, and the jig 55 is rotated in the reverse direction to the tube 57. Consequently, while notches are produced on the outer periphery of the fin by blades 56, the bent parts 59 which are in the reverse direction each other, are formed on both sides of the notch.
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