초록 ▼

A casing has a vessel portion, in which a float valve unit is arranged. A fuel drain through-hole having a small diameter is formed at a closed end bottom of the vessel portion. A cross sectional area of the fuel drain through-hole is extremely smaller than an opening area of an inlet port, so that

A casing has a vessel portion, in which a float valve unit is arranged. A fuel drain through-hole having a small diameter is formed at a closed end bottom of the vessel portion. A cross sectional area of the fuel drain through-hole is extremely smaller than an opening area of an inlet port, so that fuel discharging speed of the liquid fuel from the vessel portion through the fuel drain through-hole is suppressed to a small value. As a result, a fuel holding time of the liquid fuel in the vessel portion, which has entered into the vessel portion from the inlet port, is made longer.

대표청구항 ▼

1. A fill-up control valve device comprising: a casing attached to a fuel tank and having a ventilation passage communicating between an inside and an outside of the fuel tank, the casing including an inner wall and an outer wall both extending downward from the casing and a gap arranged between the

1. A fill-up control valve device comprising: a casing attached to a fuel tank and having a ventilation passage communicating between an inside and an outside of the fuel tank, the casing including an inner wall and an outer wall both extending downward from the casing and a gap arranged between the inner and outer walls;a float valve unit movably accommodated in a float guiding portion including the inner wall extending downward from the casing, the float valve unit being movable in a vertical direction in accordance with fuel liquid level in the casing and being brought into contact with an open end of the ventilation passage to operatively open and/or close the ventilation passage;wherein, when the fuel liquid level in the fuel tank is raised to reach a first predetermined level, the fuel liquid level in the casing is raised to a second predetermined level which is higher than the first predetermined level, so that the float valve unit is moved up to close the ventilation passage;wherein the casing has a ventilating aperture formed at a position higher than the second predetermined level, the ventilating aperture communicating between the inside of the fuel tank and the float guiding portion;wherein the casing has a vessel portion with a closed end bottom, in which the float valve unit is arranged;wherein the vessel portion further comprises: a side wall portion being arranged in the gap between the inner and outer walls extending from the casing, the side wall portion forming a liquid-fuel pooling space being configured to pool the liquid fuel and the float valve unit being arranged in the liquid-fuel pooling space;an inlet port formed at a portion higher than the closed end bottom and for introducing a part of the liquid fuel into an inside of the liquid-fuel pooling space of the vessel portion when the fuel liquid level reaches a third predetermined level higher than the second predetermined level; anda fuel drain through-hole formed at the vessel portion at a portion lower than the inlet port and for discharging the liquid fuel introduced into the inside of the vessel portion from the inlet port, and a cross sectional area of the fuel drain through-hole is smaller than an opening area of the inlet port. 2. The fill-up control valve device according to claim 1, wherein the fuel tank is mounted in a vehicle, and the casing further comprises: a fuel inlet aperture for communicating an inside of the liquid-fuel pooling portion with the inside of the vessel portion so that the liquid fuel may flow from the vessel portion into the liquid-fuel pooling portion;a fuel discharge aperture for discharging the liquid Mel pooled in the liquid-fuel pooling portion; anda valve member for closing the fuel discharge aperture when the vehicle is in its stopped condition and for opening the fuel discharge aperture when the vehicle starts its running operation,wherein the float valve unit opens the ventilation passage when a predetermined amount of the liquid fuel in the vessel portion flows into the liquid-fuel pooling portion. 3. The fill-up control valve device according to claim 2 wherein the fuel discharge aperture is formed at a lower surface portion of the liquid-fuel pooling portion,an upper surface of the lower surface portion is formed in a tapered surface, so that a surface portion away from the fuel discharge aperture becomes higher as a distance of the surface portion from the fuel discharge aperture becomes longer,the valve member has a specific gravity larger than that of the liquid fuel, andthe valve member has a ball shape and the valve member is movable in the liquid-fuel pooling portion of the casing. 4. The fill-up control valve device according to claim 2, wherein the liquid-fuel pooling portion is defined by walls of the vessel portion at a lower side of the vessel portion. 5. The fill-up control valve device according to claim 2, wherein the fuel discharge aperture is formed at a lower surface portion of the liquid-fuel pooling portion,an upper surface of the lower surface portion, which is adjacent to an upper end of the fuel discharge aperture, is formed in a first tapered surface, so that the first tapered surface portion away from the fuel discharge aperture becomes higher as a distance of the first tapered surface from the fuel discharge aperture becomes longer,another upper surface of the lower surface portion, which is located at an outer area of the first tapered surface, is formed in a second tapered surface, so that the first tapered surface away from the fuel discharge aperture becomes lower as a distance of the first tapered surface from the fuel discharge aperture becomes longer,a tapered angle of the second tapered surface is made smaller than a tapered angle of the first tapered surface,the valve member is made of such material, a specific gravity of which is larger than that of the liquid fuel, and the valve member is formed in a ball shape so that the valve member is movable in the liquid-fuel pooling portion, andan assist ball member is movably arranged in the liquid-fuel pooling portion, such that when a horizontal acceleration is applied to the assist ball member, the assist ball member pushes the valve member in a direction of opening the fuel discharge aperture, to thereby assist a valve opening operation of the valve member. 6. The fill-up control valve device according to the claim 1, wherein the cross sectional area of the fuel drain through-hole is gradually reduced from an inner side toward an outer side of the vessel portion. 7. The fill-up control valve device according to the claim 6, wherein an inner peripheral surface of the fuel drain through-hole is formed in a tapered surface. 8. The fill-up control valve device according to the claim 1, wherein a fuel guiding portion is formed at the fuel drain through-hole so that the liquid fuel flows along the fuel guiding portion. 9. The fill-up control valve device according to the claim 8, wherein the fuel guiding portion is composed of an annular projecting portion downwardly projecting from an outer periphery of a lower end of the fuel drain through-hole, anda lower end surface of the annular projecting portion is inclined with respect to an axial line of the fuel drain through-hole. 10. The fill-up control valve device according to claim 1, wherein the vessel portion further comprises: a liquid-fuel pooling portion arranged at a lower side of the closed end bottom of the vessel portion and configured for pooling liquid fuel; anda single fuel inlet aperture arranged in the closed end bottom of the vessel portion and communicating between an outside and an inside of the liquid-fuel pooling portion for liquid fuel to flow from an inside of the vessel portion into the liquid-fuel pooling portion.