| 摘要 |
PURPOSE:To provide an expansion-contraction mandrel, in which no crease is generated in the resin layer of an innermost layer, which can manufacture a molded hose having high quality and is easily inserted and extracted and workability of which can be improved and which can be used repeatedly, and the manufacture of the molded hose employing the mandrel. CONSTITUTION:A hose body 14 as a semi-finished product under an un-vulcanized or semi-vulcanized state having a resin layer 13 on an inner surface is cut in specified length, and a rubber hose-shaped mandrel 11 or a rubber tubular mandrel 12 having a small diameter smaller than the inside diameter (d) of the hose by a clearance of 0.3mm or more is inserted into the hollow section of the hose body 14. The mandrels 11, 12 are inserted, the mandrels 11, 12 are expanded and the diameters of the mandrels 11, 12 are made approximately the same as the inside diameter (d) of the hose, the mandrels are stuck fast on the inner surface of the hose body 14, and the hose body 14, into which the mandrels 11, 12 are inserted, is fitted to an outer die 15 for molding and shaped and heated, thus molding a molded form, in which there is no crease in the resin layer 13 of an innermost layer. |
