| 摘要 |
PURPOSE:To reduce insertion resistance at the time of insertion of a tube of a molding material into a mandrel and pulling-out resistance also at the time of pulling-out after molding are reduced, by a method wherein the mandrel shaping into a hose possesses a plurality of grooves in the direction running parallel with a moving direction of the molding material. CONSTITUTION:A plurality of grooves 11 by knurling processing are formed in the surface of a column of a mandrel 10 in a longitudinal direction of a parallel direction with a moving direction of a tube 20 of a molding material. In addition, the groove 11 is not formed in a part corresponding to both end parts of the tube 20 by attaching importance to sealing properties of them and they are flattened. The claylike tube 20 of unvulcanized rubber or a resin molding material is inserted into the mandrel 10 and vulcanization and heat treatments are performed. A contacting area between the mandrel 10 and tube 20 is reduced and insertion and pulling-out resistance are mitigated. |
