Pressure container manufacturing method

1. A pressure container manufacturing method for manufacturing a pressure container by forming an outer shell made of a fiber reinforced composite material on a periphery of a liner, comprising:

preparing a first fiber bundle, and a second fiber bundle;

wherein a diameter of said first diameter fiber bundle is larger than that of said second diameter fiber bundle; and wherein the first fiber bundle is unimpregnated with a resin and the second fiber bundle is covered with a thermoplastic resin to form an impregnated second fiber bundle;

forming a body on the periphery of the liner by braiding the first fiber bundle and the impregnated second fiber bundle with a braider;

impregnating the first fiber bundle with the thermoplastic resin in the second fiber bundle which is heated and melted; and

curing the thermoplastic resin to form the outer shell,

wherein a tension applied to the first fiber bundle is larger than a tension applied to the impregnated second fiber bundle when forming the body and/or impregnating the thermoplastic resin onto the first fiber bundle.

2. The method as claimed in claim 1 , wherein the liner comprises a cylindrical portion, dome portions provided on both ends of the cylindrical portion and a mouth piece attached to a top portion of at least one of the dome portions, and when the body is formed to a root portion of the mouth piece of the liner, a movement of the liner is stopped, and a formation of the body is continued while moving the liner in a direction opposite to the mouth piece along an axis direction of the liner after rotating bobbins which provide the first fiber bundle and the second fiber bundle approximately a half-turn in a circumferential direction of the liner, in the forming of the body.

3. The method as claimed in claim 1 , wherein the thermoplastic resin is any one of a polyimide, a polyphenylene sulfite and a polyethylene terephthalate.

4. The method as claimed in claim 1 , wherein the thermoplastic resin is heated to melt by an annular heater arranged around the liner.

5. The method as claimed in claim 1 , wherein the liner comprises any one of a liquid crystal resin, a synthetic resin and a metallic material.

6. The method as claimed in claim 1 , wherein the first fiber bundle and the second fiber bundle comprise any one of a carbon fiber, a glass fiber and an aramid fiber.

7. The method as claimed in claim 1 , wherein the diameter of the first fiber bundle and the diameter of the impregnated second fiber bundle are set to be approximately the same.