Patent ID: 8424819

Claim:
A fuel tank unit comprising a support body formed of resin material and housed within a fuel tank; a tank component fastened to the support body; and a fastening mechanism adapted to fasten the tank component to the support body, wherein the tank component is a fuel cutoff valve adapted to open and close a passage that connects the fuel tank interior to outside, wherein the fuel cutoff valve includes (i) a casing that is formed of resin material and defines a valve chamber and (ii) a float mechanism housed within the valve chamber and adapted to rise and fall according to fuel level, the casing including a circular disk base cover supporting the float mechanism, and the fastening mechanism includes: first and second component engaging portions that protrude from a bottom of the base cover with a hook respectively, each bite portion of the hooks being situated in a mutually facing direction, and first and second support engaging portions including apertures formed at the support body and adapted to engage the hooks respectively, wherein a first hook engagement is greater than a second hook engagement prior to fuel swelling of the support body and the casing, whereas the second hook engagement is greater than the first hook engagement after fuel swelling of the support body and the casing, the first hook engagement is defined as a bite length of which the hook of the first component engaging portion is engaged with the first support engaging portion, and the second hook engagement is defined as a bite length of which the hook of the second component engaging portion is engaged with the second support engaging portion.