| 摘要 |
PURPOSE:To improve adhering strength of the inner peripheral surface of a metal tube to a synthetic resin layer by covering the inner peripheral surface of the tube with melted resin while reducing pressure in a gap between the inner peripheral surface of the tube and the melted resin to be radially extruded in the interior of the tube. CONSTITUTION:When a metal sheet 11 is passed at the disposing position of an inner peripheral surface resin covering metal mold 30, the side edges are superposed to mold a circular tube, the superposed part is welded by a welding machine 20 as a metal tube 12. When molted resin 50 is radially extruded along the enlarged part 32d of the core 32 from a nozzle 33a at the end of a cylinder 33, it is introduced to a gap between the inner part 32e of the end of the core 32 and the inner peripheral surface of the tube 11 to cover the inner peripheral surface of the tube 11. In this case, the air in a space surrounded by the inner peripheral surface of the tube 11, the outer peripheral surface of the cylinder 33, a shielding plate 43, and the resin 50 is sucked by a suction tube 45 connected to a vacuum pump to reduce under pressure in the space. Thus, the gap between the resin 50 and the inner peripheral surface of the tube 11 is reduced under pressure, and the resin 50 rigidly adheres to the all inner peripheral surface of the tube 11 in close contact. |
