Fuel hose for resin fuel tank and method of producing the same

A method of producing a fuel hose for a resin fuel tank, said method comprising the steps of:

• while circulating an upper die set including a plurality of upper dies coupled to each other in the form of an endless loop and a lower die set including a plurality of lower dies coupled to each other in the form of an endless loop, sequentially bringing the upper and lower dies in pairs together to form a generally cylindrical molding space;
• extruding a hose base body of a generally cylindrical configuration made of a material for production of the fuel hose from an extruder into the molding space to bring the hose base body into intimate contact with a die surface facing the molding space, thereby making the hose base body in the form of a continuous hose;
• and
• sequentially separating the upper and lower dies in pairs from each other to remove the continuous hose from the upper and lower dies,
• the die surface facing the molding space defined by a predetermined pair of upper and lower dies in the upper and lower die sets being formed with an increased diameter portion,
• the hose base body having a triple layer structure including a barrier layer base material of a generally cylindrical configuration, a first welding layer base material of a generally cylindrical configuration formed on an inner peripheral surface of said barrier layer base material, and a second welding layer base material of a generally cylindrical configuration formed on an outer peripheral surface of said barrier layer base material, said barrier layer base material being made of an alloy material consisting primarily of ethylene vinyl alcohol copolymer and modified high density polyethylene, said first and second welding layer base materials being made of high density polyethylene,
• the upper die set and the lower die set being adapted to circulate at a reduced speed when said hose base body is extruded from the extruder to the increased diameter portion of the die surface, to thereby configure the hose base body at a portion extruded into the increased diameter portion in the form of an increased diameter portion and in the form of a thick-walled portion,
• said method further comprising the step of
• cutting said increased diameter portion of the continuous hose in a circumferential direction after the continuous hose is removed.