| CPC B29C 48/10 (2019.02) [B29C 48/151 (2019.02); B29L 2023/005 (2013.01)] | 5 Claims |
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1. A flexible tube production apparatus for extrusion molding a flexible tube, the flexible tube production apparatus comprising:
a first extruder that extrudes a first resin;
a second extruder that extrudes a second resin more flexible than the first resin;
a third extruder that extrudes a third resin more flexible than the first resin and the second resin;
a die that has a first penetrating hole through which a braded wire is inserted, an extrusion port extruding the resins onto a surface of the braded wire passing through the first penetrating hole, and a flow passage in communication with the extrusion port;
a first valve that is switchable between a state in which the first extruder and the flow passage of the die are in communication and a state in which the first extruder and the flow passage of the die are interrupted from each other;
a second valve that is switchable between a state in which the second extruder and the flow passage of the die are in communication and a state in which the second extruder and the flow passage of the die are interrupted from each other; and
a third valve that is switchable between a state in which the third extruder and the flow passage of the die are in communication and a state in which the third extruder and the flow passage of the die are interrupted from each other; and
wherein a first supply passage connecting the first valve and the flow passage, a second supply passage connecting the second valve and the flow passage, and a third supply passage connecting the third valve and the flow passage are provided inside the die,
the die has:
an inner die that has a straight portion of circular columnar outer shape and a convergent tapered portion provided closer to the extrusion port side than the straight portion; and
an outer die that has a hollow portion and houses the inner die in the hollow portion with there being a predetermined interval, serving as the flow passage, from an outer surface of the inner die, and
downstream side end portions of the first supply passage and the second supply passage are connected to a portion of the flow passage formed between the straight portion and the outer die, and a downstream side end portion of the third supply passage is connected to a portion of the flow passage formed between the tapered portion and the outer die.
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