To improve the strength of a straight part without impairing the flexibility of a corrugated part.
The tube 10 has: a corrugated part 11; and a small diameter straight part 12 and a large diameter straight part 13 which constitute both ends of the tube 10. Thickness T3 of the large diameter straight part 13 is not less than thickness T2 of the small diameter straight part 12. Thickness of the corrugated part 11 is less than thickness T2. The tube 10 is molded by extrusion-supplying a thermoplastic resin into a moving molding die. Moving speed V1 of the molding die at the time of supplying the thermoplastic resin to a molding face corresponding to the corrugated part 11 is faster than moving speed V2 of a tube molding die at the time of supplying the thermoplastic resin to the molding face corresponding to the small diameter straight part 12. The moving speed V2 is faster than moving speed V3 of the tube molding die at the time of supplying the thermoplastic resin to the molding face corresponding to the large diameter straight part 13.
NISHIDE SHOJI
SAWAHIRA YOSHIHIRO
Hiroki Ogura
Tsuyoshi Nonaka
Shigeru Torayama
Tsubouchi Shin
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