Fuel tank opening and closing device

A fuel tank opening and closing device for opening and closing a path for supplying fuel to a fuel tank, the fuel tank opening and closing device comprising:

• a tank opening forming member that forms (i) a fuel path connected to the fuel tank, (ii) an insertion path for inserting as fueling nozzle, the insertion path having an introduction port and connecting the introduction port to the fuel path and (iii) an inlet disposed between the fuel path and the insertion path;
• a flap valve mechanism that is arranged inside the tank opening forming member, and has an opening and closing member for opening and closing the inlet by being pressed by an end of the fueling nozzle and by pivoting about an axis of a spring biasing the opening and closing member toward closing;
• and
• a nozzle positioning guide mechanism that guides the fueling nozzle from the introduction port to an insertion completion position through the insertion path, the inlet opened by the opening and closing member in the fuel path, and positions the fueling nozzle at the insertion completion position, wherein the insertion completion position is a position at which fuel is supplied by the fueling nozzle into the fuel path,
• wherein the nozzle positioning guide mechanism includes:
• a first support mechanism being formed on an opening peripheral edge of the introduction port, the first support mechanism guiding the fueling nozzle in an insertion direction while contacting with an outer periphery part of the fueling nozzle and positioning the fueling nozzle at the insertion completion position,
• a second support mechanism that has an introduction guide surface and a positioning ridge line formed on an upper surface of the opening and closing member respectively, wherein the introduction guide surface is a recess with a radius of curvature greater than a curvature of a radius of the fueling nozzle and conveys force in a direction for opening the opening and closing member while the end of the fueling nozzle slides thereon, and wherein the positioning ridge line is formed on a part of the introduction guide surface and contacts the outer periphery surface of the fueling nozzle at the insertion completion position, the positioning ridge line having almost the same curvature as the curvature of the radius of the fueling nozzle and positioning the end of the fueling nozzle in a horizontal direction, and the radius of curvature of the introduction guide surface extends in a plane that is parallel to the axis of the spring,
• a third support mechanism that is formed on the opening and closing member, and has a valve positioning member which regulates a degree of openness of the opening and closing member by touching an inner wall of the tank opening forming member at the insertion completion position, and
• the opening and closing member includes a pressing member receiving the pressure force of the fuel nozzle, a value chamber forming member forming a valve chamber with the pressing member, a pressure regulating valve housed in the value chamber and a sidewall in which a ventilation hole is formed to pass air to the pressure regulating valve.