Method of manufacturing high pressure gas tank

A method of manufacturing a high pressure gas tank including a fiber layer formed by mounting nozzles on apexes of dome sections of both ends of a liner in an axial direction and repeatedly winding a fiber bundle on an external surface of the liner, the method comprising:

• preparing the liner having pedestal sections having outer surfaces on which the dome sections are installed along an uniform stress surface and concave surfaces on which the nozzles are mounted on the apexes of the dome sections;
• mounting the nozzles having nozzle flanges entering the pedestal sections and nozzle main bodies protruding from the nozzle flanges toward end sides of the liner on the apexes such that the nozzle flanges enter the pedestal sections;
• mounting ring-shaped caps on boundary portions between flange outer circumferential edges of the nozzle flanges entering the pedestal sections and inner circumferential walls of the pedestal sections, and covering boundary gaps of the boundary portions with the caps;
• and
• forming the fiber layer by repeatedly winding the fiber bundle impregnated with a thermosetting resin on the external surface of the liner when the nozzles and the caps are mounted;
• wherein
• the caps having same linear expansion coefficients as the liner and inner surfaces in a curved surface shape of outer surfaces of the dome sections and outer surfaces of the nozzle flanges are used as the ring-shaped caps when the boundary gaps are covered with the caps, and a helical winding layer is formed first by winding the fiber bundle while including the nozzle flanges to cover the dome sections such that the fiber bundle is disposed on the dome sections of both ends in the axial direction when the fiber layer is formed.