| 摘要 |
PURPOSE:To reduce fluid resistance in the tube and to improve strength of the tube by providing a groove of axial direction on inner peripheral side of bend of a form guide or mandrel etc. and forming a projected vein of axial direction on the tube wall. CONSTITUTION:The plaited bent tube manufacturing device 1 has a form guide 3 attached to a turning driving shaft 2, and a groove 5A extending in peripheral direction is provided on its forming face 5. When a guide 3 is rotated by driving the turning driving shaft 2, a tube 4 is bent constrained by the forming face 5 of the guide 3. Consequently, a projected vein 13 of axial direction is formed on outer face of tube wall of inner peripheral side of bending by rolling effect of the form guide 3 and mandrel 11. As the bellows do not form on inner wall of the tube, the fluid resistance in the tube is reduced, and the mechanical strength of the tube is increased by the projected vein 13. |
