| 摘要 |
<p>PROBLEM TO BE SOLVED: To reduce the number of stages and to manufacture a bent/turned tube at low cost by forming an outward curled part at a tube end and, after that, forming a bent/turned part by moving by pressing the curled part to the side of the tube part in the axial direction of a tube. SOLUTION: After situating the curled part 4 on a die hole 5a, load P3 by which a tube stock 1 can be bent at the other end 1b of a tube stock 1 is added to the side of a die 5 for working a turnover in the axial direction of the tube. The tube stock 1 is bent and turned over by this load P3 and plastically deformed bent/turned part 6 is formed. By the moving amount of the tube stock 1 in the axial direction by this load P3 , that is, the lowering amount, the length of the bent/turned part 6 is set and, by lengthening the lowering amount, the bent/turned part 6 is lengthened. By releasing the tube stock from the die with the die 5 for working the turnover, the bent/turned tube whose one end is a double tube and which has the curled part 4 in the end part of the outer tube is obtained. Consequently, the forming die and forming equipment are simplified and the cost of die and cost of equipment are reduced.</p> |
