PURPOSE: To prevent the shortage of pressure resistance caused by the thickness irregularity of a product or the frequent occurrence of an inferior product caused by shape irregularity, by a method wherein primary vulcanization is applied to a hose material in a straight state and a bent mandrel is subsequently inserted into the vulcanized hose material to perform secondary vulcanization.
CONSTITUTION: Primary vulcanization is performed in a straight state not inserting a bent mandrel. In the next step, the bent mandrel having a desired shape is inserted into the hose material vulcanized and cured to a certain degree and secondary vulcanization is performed to carry out habit-formation in a desired bent shape. Thereafter, the bent mandrel is pulled out to obtain a product. In the pulling-out of the mandrel in this case, difficulty is slightly increased but can be sufficiently compensated by properly using a release agent.
CHIYOUKAI HIROKI
NAKAMURA YASUTAKA
KITAYAMA HIROSHI
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