| 摘要 |
PURPOSE:To enable covering the title tube with a substantially uniform thickness by locally heating melted resin adhering to the inner peripheral face of a metal tube. CONSTITUTION:A metal sheet 70 is shaped in a circularly tubular state during passage of a gap between a resin flowing tube 12 and an outer die 30, the side edges of the sheet 70 adhere by a welding machine 40 thereby to form a metal tube 71. Melted resin flows in a gap between the inner peripheral face of the tube 12 and the outer peripheral face of a core 13, and is extruded while extending outward. The extruded resin is into contact with the inner peripheral face of the tube 71, formed in a predetermined thickness between the end 13a of the core 13 and the inner peripheral face of the tube 71, strongly brought into pressure contact with the inner peripheral face of the tube 71 at the end 13a of the core 13 to adhere to the inner peripheral face of the tube 71. When a synthetic resin layer is in an irregularly thick state, a heater 51 opposed through the tube 71 in a heating device 50 to the thick part is operated to heat the thick part, thereby forming a circumferentially and substantially uniform thickness. |
