| 摘要 |
PROBLEM TO BE SOLVED: To provide a device and a method for manufacturing a tube with grooved inner face by which grooves can be uniformly formed less liable to break the tube during machining even when using a long tube. SOLUTION: Straightening rolls 25a-25e alternately press the side on the curved center side and the outer side of a stock tube 1 curved through the curl by straightening machines which are alternately disposed, i.e., disposed in a staggered manner on both sides of the stock tube 1, straighten the curl, and insert the stock tube into a holding die 3. Next, the shape and the wall thickness of the stock tube 1 are unified by the holding die 3 and a holding plug 2, and a first groove is formed by a form rolling unit 7a. Then, the stock tube 1 is contracted by a sizing die 8a, and a second groove is formed by a form rolling unit 7b. The stock tube is contracted by a sizing die 8b to form an inside groove tube. COPYRIGHT: (C)2005,JPO&NCIPI
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