1. Field of the Invention
The present invention relates to a fuel tank structure for a saddle-ride type vehicle.
2. Description of Background Art
In order to limit the discharge of vaporized fuel in the fuel tank toward the outside of the tank, fuel tanks have heretofore been increased and are designed not to release tank inner pressure to the atmosphere when pressure in the fuel tank is equal to or lower than a predetermined pressure.
In this case, although the pressure in the fuel tank is equal to or lower than the predetermined pressure, a certain level of pressure is released from around a tank cap when a filler neck of the fuel tank is opened. Therefore, a quantity of fuel may possibly leak out from the filler neck.
On the other hand, Japanese Patent Laid-Open No. Hei 10-236366 discloses the structure wherein a cover member covers the periphery of a filler neck of a fuel tank of a saddle-ride type vehicle to make the upwardly projection of a tank cap inconspicuous. In addition, a passage for discharging downwardly the fuel and the like coming from a breathing hole provided in the tank cap is formed by a gap between the upper surface of the fuel tank and the cover member.
In this case, the tank cap has a second seal member for closing the gap between the outer circumferential portion of the tank cap and the cover member in addition to a first seal member for closing the filler neck. The second seal member is designed to efficiently lead the fuel leaking from the filler neck to the gap between the cover member and the fuel tank for discharge.
The second seal member for closing the gap between the tank cap and the cover member is provided in addition to the first seal member for closing the filler neck as in the above conventional technology. In such a case, however, there is a problem in that it is necessary to set tightening margins, loads and the like accurately so as to allow both the seal members to function appropriately, which easily leads to an increase in the cost.