Patent ID: 7810474

Claim:
A fuel tank venting device comprising a fuel cutoff valve unit adapted to open and close a passage leading to a canister according to a fuel level in a fuel tank; and a fuel tank valve unit connected to the fuel cutoff valve unit through a pipe and adapted to open and close the passage according to tank internal pressure, wherein the fuel cutoff valve unit includes (i) a first fuel cutoff valve adapted to close a first connecting passage through uplift of a first float mechanism when the fuel level in the fuel tank has exceeded a first level, and (ii) a second fuel cutoff valve adapted to close a second connecting passage through uplift of a second float mechanism when the fuel level in the fuel tank has exceeded a second level higher than the first level, and the fuel tank valve unit includes (i) a first connector tube part that has a first flow passage connecting the first connecting passage with the canister, (ii) a second connector tube part that has a second flow passage connecting the second connecting passage with the first flow passage, and (iii) a pressure valve adapted to open and close the passage according to the tank internal pressure through the second flow passage, wherein the pressure valve includes (i) a casing that has a valve chamber situated facing the second flow passage, (ii) a valve body housed within the valve chamber to open and close a valve aperture that is formed in the casing and disposed facing the second flow passage, and (iii) a spring for urging the valve body towards a closed direction, wherein the valve body has (i) a valve part, (ii) a side wall projecting with tubular contours from an outer circumference of the valve part, (iii) a spring chamber bounded by the valve part and the side wall and adapted to receive the spring, and (iv) an orifice perforated in the valve part with smaller planar dimensions than the valve aperture.