JP2943638B2 - Float valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a float valve which is disposed above a fuel tank of a vehicle and controls the outflow of fuel when the fuel tank is full and at the time of fuel filling. About.

[0002]

2. Description of the Related Art Hitherto, as this type of float valve, those disclosed in Japanese Patent Application Laid-Open No. Hei 5-185850 and Japanese Utility Model Publication No. Hei 4-39061 have been known, and have a configuration as shown in FIG.

[0003] That is, the float valve 100 is
02a, a bottomed cylindrical case 102 surrounded by a side wall portion 102b and a bottom wall portion 102c, and a float 110 stored in a float chamber 104 formed in the case 102
A valve portion 110a formed at the top of the float 110 and capable of closing the air outflow passage 111;
, And a coil spring 114 disposed between the bottom surface of the case 102 and the bottom wall 102c of the case 102. In the case 102, through holes 118 are formed in the side wall portion 102a and the bottom wall portion 102c, respectively, so that the air A can flow into the float chamber 104.

[0004] In the float valve 100 having such a configuration, when the fuel tank FT is refueled, the air A in the fuel tank FT flows out through the through hole 118 formed in the case 102, the float chamber 104, and the air outflow passage 111. I do. Then, when the fuel in the fuel tank FT is full
When the fuel cell reaches L, the fuel flows into the float chamber 104 through the through hole 118 and gives buoyancy to float the float 110. Float 110 is lifted by float 110
The valve portion 110a formed at the top of the air outlet passage 111
To prevent the fuel from flowing out of the fuel tank FT.

[0005]

However, in the above-mentioned float valve 100, the float 110 rises and the valve portion 1
The full tank level FL when the air outflow passage 111 is closed at 10a is uniformly determined by the spring force of the coil spring 114 of the float valve 100, the weight of the float 110, and the buoyancy generated in the float 110. Therefore, the fuel tank F
There is a disadvantage that the design of the float valve 100 itself needs to be changed in order to cope with the unique full liquid level of each T.

The present invention has been made to solve the above-mentioned problems of the prior art, and can cope with a unique full liquid level of each of various fuel tanks, without changing the configuration of the fuel tank itself. It is an object of the present invention to provide a float valve which may be used.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to a case in which a float chamber is formed above a fuel tank and a float chamber is formed, and an air outflow passage is provided in the upper part of the case. A float valve body having a float housed in a room, and having a valve portion capable of closing an air outflow passage at an upper portion of the float, the case surrounding the outer surface of the float, and having a lower opening at a lower portion. A side wall portion having a through hole that is detachably provided at a lower portion of the side wall portion so as to close the lower opening, and is opened at a position of a fuel liquid level when the fuel tank is properly filled with fuel. And a bottom plate.

[0008]

In the float valve according to the present invention, when fuel is supplied to the fuel tank, the air in the fuel tank flows out through a through hole formed in the bottom plate of the case, the float chamber, and the air outflow passage. When the fuel in the fuel tank is full and the fuel flows into the float chamber through the through hole in the bottom plate, the fuel gives buoyancy to float the float. When the float rises, the valve formed at the top of the float closes the air outflow passage, thereby preventing the fuel tank from flowing out of the fuel tank.

The rise of the float and the closing of the air outlet passage by the valve portion are determined by the position of the through hole through which the fuel flows into the float chamber. The through-hole is formed in a bottom plate, and the bottom plate is detachably provided on a side wall of the case. Therefore, by replacing the bottom plate with a different position of the through hole, the full tank level of the fuel tank can be changed.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to further clarify the structure and operation of the present invention described above, preferred embodiments of the present invention will be described below.

FIG. 1 is a sectional view showing a fuel vapor pressure control valve FV according to an embodiment of the present invention. Fuel vapor pressure control valve FV
Is mounted on the upper part of the fuel tank FT, and includes a case 16 composed of a case lower body 12 and a case upper body 14 fixed to the upper part of the case lower body 12. And a diaphragm valve 60 connected to the float valve 20 and a canister (not shown).

The float valve 20 is connected to the fuel tank F when refueling.
When the fuel in T rises to a predetermined full tank level FL1, the outflow to the outside is regulated. On the other hand, when the fuel vapor pressure in the fuel tank FT becomes equal to or higher than a predetermined pressure, the diaphragm valve 60 opens to discharge the fuel vapor to the canister side.

First, the float valve 20 will be described.
As shown in FIG. 2, the float valve 20 is connected to a fuel tank FT.
A float 40 which is mounted on the upper wall FTa of the case and is disposed in the float chamber 22 in the case lower body 12;
The coil spring 50 that assists the valve closing operation of the float 40 is configured as a main element.

The case lower body 12 is formed of a synthetic resin having a resistance to fuel oil, and has a ceiling wall portion 32 which constitutes a part of the diaphragm valve 60, and extends downwardly from the ceiling wall portion 32 in a cylindrical shape. And a bottom plate 34 which is detachably attached to a lower portion of the side wall portion 33 and closes the lower opening 12a.

The ceiling wall portion 32 has a steam communication passage 32a communicating with the diaphragm valve 60 at the center thereof, and a peripheral portion of the inlet of the steam communication passage 32a has a seat surface 32a.
b.

The side wall portion 33 has a flange portion 33a at an upper portion thereof, and the fuel tank FT is formed by the flange portion 33a.
Is mounted via a gasket GK or the like. A rectangular outer through hole 33b (see FIG.
), And an engagement through hole 33c for attaching the bottom plate 34 is formed below the lower portion. further,
A float 4 extending in the vertical direction is provided on the inner peripheral portion of the side wall portion 33.
A plurality of guide ridges 33d for guiding 0 are formed. The fine holes 34g formed in the outer peripheral bottom surface portion 34a have a role of discharging the fuel accumulated in the inner space of the bottom plate 34, and do not affect the full tank liquid level FL1.

The bottom plate 34 has an outer peripheral bottom portion 34a, and a cylindrical standing wall portion 34 which is erected upward from the outer peripheral portion of the outer peripheral bottom portion 34a and fitted on the inner peripheral side of the side wall portion 33.
b, and a pedestal portion 34c erected in a cylindrical shape on the inner peripheral side of the outer peripheral bottom surface portion 34a, and these are integrally formed.
The upright wall portion 34b has an engaging through hole 33 formed in the side wall portion 33.
c is formed, and the engagement protrusion 34d is engaged with the engagement through hole 33c.
This bottom plate 34 is mounted on the bottom of the side wall 33. A spring support projection 3 is provided at the upper center of the base 34c.
4e are formed. The spring support projection 34e supports the coil spring 50 between itself and the lower surface of the float 40.

As shown in FIG. 3 and FIG.
In the upper part of the upright wall part 34b, a rectangular inner through hole 34 located above the outer through hole 33b of the side wall part 33 is formed.
f is formed. Therefore, the inside of the fuel tank FT communicates with the inside of the float chamber 22 through the outer through hole 33b and the inner through hole 34f.

Returning to FIG. 2, the float 40 is formed in a container shape having a float upper surface portion 41 and a cylindrical float side wall portion 42 formed below the outer periphery of the float upper surface portion 41. The inner space is a buoyancy chamber 40S for generating buoyancy. The float 40 is
The float 40 is supported by the coil spring 50 so that its lower end is located above the height of the inner through hole 34f of the bottom plate 34.

An annular step 41a is provided on the float upper surface 41.
And a seal ring 43 is attached to the outer periphery of the annular step portion 41a. This seal ring 43
Opens and closes the steam communication passage 32a by being attached to and detached from a sheet surface 32b formed around the steam communication passage 32a. Considering the sealing property and fuel oil resistance, fluorine rubber, nitrile rubber, etc. Is formed from a rubber material. A guide ridge 42 a is formed in the outer peripheral portion of the float side wall portion 42 in a vertical direction, and the guide ridge 42 a is fitted to a guide ridge 33 d formed on the inner peripheral wall surface of the side wall portion 33. To guide the float 40 up and down.

Next, the operation of the float valve 20 will be described. When the fuel is supplied into the fuel tank FT by refueling, the fuel vapor accumulated in the upper part of the fuel tank FT becomes higher than a predetermined pressure when the fuel vapor becomes higher than a predetermined pressure.
3, the diaphragm valve 60 is further opened through the gap between the side wall 33 and the float side wall 42 of the float 40, the steam communication passage 32a through the outer through hole 33b of the bottom plate 34, and the flow through the canister. .

When the fuel level in the fuel tank FT reaches the full tank level FL1, the fuel flows into the float chamber 22 through the outer through hole 33b of the side wall 33 and the inner through hole 34f of the bottom plate 34. Thereby, the float 40
Of the steam communication passage 32a is closed by the seal ring 43 to prevent the fuel from flowing out to the canister side.

As described above, in the float valve 20, the float 40 is connected to the coil spring 5 so that the lower end of the float 40 is located above the height of the inner through hole 34f of the bottom plate 34.
Therefore, even if the flow velocity of the fuel vapor flowing through the inner through-hole 34f is high, the flow of the fuel vapor alone does not generate buoyancy enough to raise the float 40, and the fuel flows into the float chamber 22. Only when it enters, the float 40 is lifted and the valve is closed.

As described above, the full tank level FL1 when the float valve 20 is closed is determined by the position of the inner through hole 34f through which the fuel in the fuel tank FT flows into the float chamber 22. Therefore, by changing the height position of the inner through hole 34f, the full tank liquid level FL1 can be changed.

Accordingly, the float valve 20 having a different full liquid level can be handled by using the bottom plate 34B shown in FIGS. That is, the inner through hole 34Bf formed in the bottom plate 34B is
Is located below the inside through hole 34f of the bottom plate 34 in FIG. 3 and its full tank level is FL2. Since the bottom plate 34B has the same configuration as the bottom plate 34 of FIG. 3 except for the position of the inner through-hole 34Bf, the bottom plate 34B can be easily replaced with the bottom plate 34.

Therefore, if a bottom plate 34B having a different position of the inner through hole 34Bf is prepared and appropriately selected, the full tank level of the fuel tank FT can be changed, and the design of the fuel tank FT can be changed. Even if they are not provided, it is possible to support various fuel tanks FT.

Further, the bottom plates 34 and 34B are also simple in their structure, and are more advantageous in cost than replacing the case 16 having a different through hole position to determine the full tank level.

The shape of the bottom plate 34 is not particularly limited as long as the float chamber 22 is formed in the case 16 and can be attached to and detached from the case 16 in addition to those described above. As described above, the bottom plate 34C may have a shape protruding from the lower portion of the side wall portion 33C. In this case, it is not necessary to form a through hole in the side wall 33C, and the full tank level FL3 is determined at the position of the through hole 34Cf.

Further, the positions of the through holes formed in the bottom plate are as follows:
Not only the side surface but also the bottom surface may be used. In this case, the position of the through hole can be changed by forming a large-diameter hole that also serves as an air vent hole and changing the height of the bottom plate.

Next, regarding the diaphragm valve 60, FIG.
8 will be described in an enlarged manner and FIG. 9 which is a perspective view showing a main part thereof cut away. The diaphragm valve 60 is
A diaphragm valve body 62, a guide member 63 that holds the diaphragm valve body 62, and a coil spring 64 are provided in a diaphragm valve chamber 60 </ b> S formed by the upper part of the case lower body 12 and the case upper body 14. Have.

The diaphragm valve element 62 has a flat seating portion 62a, a mounting protruding portion 62b projecting from the seating portion 62a and attaching a guide member 63, and a seating portion 62a.
And a pressure receiving portion 62c provided on the outer periphery of the case upper portion 14 and the case lower portion 1
The diaphragm valve chamber 60S is divided into a reference pressure chamber 70S and a fluid pressure chamber 71S by being sandwiched between outer peripheral portions of the second flange portion 12b.

The reference pressure chamber 70S is provided with the case upper body 14.
Is connected to an outside air introduction passage 72S formed in an outside air introduction pipe portion 72 projecting horizontally from the side of the reference pressure chamber 70S. Therefore, the inside of the reference pressure chamber 70S is set to the atmospheric pressure.

Below the fluid pressure chamber 71S, there is formed a steam communication pipe portion 73 projecting above the lower case body 12. The steam communication pipe 73 forms a steam communication passage 32 a above the float valve 20. The fluid pressure chamber 71 is provided on both sides of the upper portion of the steam communication passage 32a.
Connected to S.

The lower portion of the fluid pressure chamber 71S is separated by a partition wall 74 and the flange portion 12 of the case lower body 12 is formed.
b, a disc-shaped discharge chamber 76S surrounded by the outer periphery of the case upper body 14. Also, at the upper center of the partition 74,
An annular seat portion 77 on which the seating portion 62a of the diaphragm valve body 62 is detached is formed. In the seat portion 77, when the diaphragm valve body 62 is separated from the seat portion 77, the fluid pressure chamber 71S is formed. An outflow passage 78S communicating with the disc-shaped discharge chamber 76S is formed.

An outer expansion chamber 79S is annularly connected to the outer periphery of the disk-shaped discharge chamber 76S. The outer expansion chamber 79S is formed by being surrounded by the side wall portion 14a of the case upper body 14 and the outer peripheral portion of the flange portion 12b of the case lower body 12. Height h1 of outer expansion chamber 79S
Is higher than the height h2 of the disc-shaped discharge chamber 76S, and is formed to have substantially the same thickness as the diaphragm valve 60.

Further, a discharge pipe 81 is protruded from a side portion of the case upper body 14, and a discharge passage 81S is formed in the discharge pipe 81. This discharge passage 81S
Has a circular cross section, is connected to the outer expansion chamber 79S, and has an inner diameter D slightly smaller than the height h1 of the outer expansion chamber 79S.

Next, the operation of the diaphragm valve 60 will be described. The fuel vapor pressure of the fuel tank FT is applied to the fluid pressure chamber 71S through the float valve 20 and the vapor communication passage 32a, but when the value exceeds the pressure of the reference pressure chamber 70S and the force of the coil spring 64, the diaphragm valve body 62 opens the outflow passage 78S apart from the sheet portion 77. Thereby, the steam communication passage 32a is connected to the fluid pressure chamber 71S and the outflow passage 7
8S, the disc-shaped discharge chamber 76S, and the outer expansion chamber 79S communicate with the discharge passage 81S.

In such a configuration, the outflow passage 78S, the disc-shaped discharge chamber 76S, and the outside expansion chamber 79S are
If the area of the passage connected to the valve member becomes small in the middle, a force for preventing the valve from closing is applied to the diaphragm valve body 62, and the opening and closing operation of the diaphragm valve body 62 becomes unstable, which is not preferable.

Therefore, in order to satisfy the condition that the passage area is not reduced in the middle, to make the passage area as large as possible and to make the diaphragm valve 60 thin and compact, first, the fluid pressure chamber 71S Is formed as a thin flat disk-shaped discharge chamber 76S.
If the discharge passage 81S having an inner diameter equal to the height h2 of the disc-shaped discharge chamber 76S thus thinned is simply connected, a sufficient passage area of the discharge passage 81S cannot be secured. By interposing the outer expansion chamber 79S having a height h1 expanded to the upper position of the pressure chamber 70S, it can be connected to the discharge passage 81S having a large inner diameter D. By adopting this configuration and passage arrangement, even if the inner diameter D of the discharge passage 81S is increased, the outer diameter of the discharge conduit portion 81 is substantially equal to the thickness of the diaphragm valve 60, and is smaller than that of the diaphragm valve 60. Become.

In the above embodiment, the outer expansion chamber 79S
Is formed over the entire outer periphery of the disc-shaped discharge chamber 76S, but is not limited thereto, and may be provided in a fan shape with a predetermined angle connected to the discharge passage 81S. What is necessary is just to intervene while ensuring a passage area that does not reduce the passage area of the discharge passage 81S from the discharge chamber 76S.

Further, in the above embodiment, the diaphragm valve is operated at the atmospheric pressure. However, the invention is not limited to this. For example, the diaphragm valve may be operated at another reference pressure. It may be operated with.

[0042]

As described above, according to the float valve of the present invention, the bottom plate is formed with a through hole for determining the full tank level of the fuel tank, and the bottom plate is attached to and detached from the lower portion of the side wall of the case. If the fuel tank is replaced with a bottom plate having a different position of the through hole, the full tank level of the fuel tank can be easily changed. Therefore, the float valve according to the present invention can cope with the unique full liquid level of each of the various fuel tanks, and the configuration of the float valve itself does not need to be changed.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a fuel vapor pressure control valve.

FIG. 2 is a sectional view showing a float valve.

FIG. 3 is an enlarged sectional view of a lower portion of the float valve of FIG. 2;

FIG. 4 is an enlarged sectional view of a lower portion of the float valve having a lower liquid level than that of FIG. 3;

FIG. 5 is an explanatory diagram for explaining a full tank level of the float valve of FIG. 3;

FIG. 6 is an explanatory diagram for explaining a full tank level of the float valve of FIG. 4;

FIG. 7 is a sectional view showing a float valve according to another embodiment.

FIG. 8 is a cross-sectional view showing a diaphragm valve.

FIG. 9 is a perspective view showing a main part of the diaphragm valve in a cutaway manner.

FIG. 10 is a sectional view showing a conventional float valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 12 ... Case lower body 12a ... Lower opening part 12b ... Flange part 14 ... Case upper body 14a ... Side wall part 16 ... Case 20 ... Float valve 22 ... Float room 32 ... Ceiling wall part 32a ... Steam communication path 32b ... Seat surface 33 ... Side wall 33C Side wall 33a Flange 33b Outside through hole 33c Engagement through hole 33d Guide ridge 34, 34B, 34C Bottom plate 34Bf Inside through hole 34Cf Through hole 34a Outer peripheral bottom surface 34b Standing wall Part 34c Base part 34d Engagement protrusion 34e Spring support protrusion 34f Inner through hole 34g Fine pore 40 Float 40S Buoyancy chamber 41 Float upper surface part 41a Annular step part 42 Float side wall part 42a Guide Ridge 43 ... Seal ring 50 ... Coil spring 60 ... Diaphragm valve 60S ... Diaphragm valve chamber 62 ... Diaphragm Valve body 62a ... Seat portion 62b ... Mounting protrusion 62c ... Pressure receiving portion 63 ... Guide member 64 ... Coil spring 70S ... Reference pressure chamber 71S ... Fluid pressure chamber 72 ... Outside air introduction pipe 72S ... Outside air introduction passage 73 ... Steam communication Pipe part 74 ... Partition wall 76S ... Disc-shaped discharge chamber 77 ... Seat part 78S ... Outflow passage 79S ... Outside expansion chamber 81 ... Discharge pipe part 81S ... Discharge passage FT ... Fuel tank FV ... Fuel vapor pressure control valve GK ... Gasket FL1 , FL2, FL3 ... Full tank level

Claims (1)

(57) [Claims] 1. A float disposed in an upper part of a fuel tank to form a float chamber and having an air outflow passage in an upper part thereof, and a float housed in the float chamber. A float valve body having a valve portion capable of closing the air outflow passage, wherein the case surrounds an outer side surface of the float, has a lower opening at a lower portion, and a side wall portion that closes the lower opening. And a bottom plate provided detachably at a lower portion and having a through hole opened at a position of a fuel liquid level when the fuel tank is fully refilled.