JP3419194B2 - Liquid shutoff 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 liquid cutoff valve provided in, for example, a fuel tank of an automobile or the like,
The present invention relates to a liquid cutoff valve that functions to prevent gas such as fuel vapor from being discharged from a discharge path connected to a valve but prevent liquid such as fuel from leaking to the discharge path.

[0002]

2. Description of the Related Art As a conventional liquid cutoff valve of this type, there is one which is mounted on a fuel tank 101 of a vehicle as shown in FIG. 6, for example. That is, the liquid cutoff valve 102 is provided above the fuel tank 101,
The fuel vapor G101 generated inside is exhausted to the exhaust path 103. The discharge path 103 is provided with a canister 104 that absorbs the exhausted fuel vapor G101 to prevent the fuel vapor G101 from being released into the atmosphere.

Further, the liquid cutoff valve 102 discharges the fuel L101 when the water level of the fuel L101 rises or the vehicle leans or falls due to the shaking of the vehicle.
It also has a liquid shut-off function that prevents it from leaking out.

FIG. 7 is a sectional view showing the basic structure of the liquid cutoff valve 102 and its operation. 110 is a case part, and the inside is a float chamber 110a for accommodating the float 111. Float 111 is communication hole 1
Fuel L10 flowing into the float chamber 110a from 12
1 causes buoyancy to move upward in the state shown in this figure. Reference numeral 113 is a spring that functions as a biasing means for adjusting the buoyancy of the float 111.

On the upper part of the float 111, there is an annular seal portion 111a which functions as a valve body, and the float chamber 11
0a and the valve seat portion 110b on the outside of the region to which the discharge path 103 is connected to contact the valve seat portion 110b to shut off the inside of the fuel tank 101 from the discharge path 103.

Therefore, the state of FIG. 7 is the float chamber 110a.
The fuel L101 flows into the valve, the float 111 moves upward, and the discharge path 103 is blocked. Then, as the water level of the fuel L101 in the float chamber 110a lowers, the float 111 also moves downward and the discharge path 10
3 returns to a normal state in which the fuel tank 101 communicates with the fuel tank 101.

In recent years, such a liquid cutoff valve 10 has been used.
In No. 2, there was a demand for smoother fuel vapor discharge. Therefore, the liquid cutoff valve 102 shown in FIG. 7 is provided with a seal portion 111a having a relatively large diameter as the discharge passage has a larger cross-sectional area.

However, the float 111 provided with the seal portion 111a having such a large diameter has a discharge path when the pressure inside the fuel tank 101 is high even when the fuel L101 returns from the float chamber 110a to the fuel tank 101. There is a problem in that the upward biasing force generated in the float 111 exceeds the weight of the float 111 due to the pressure difference from the side, and the discharge path remains closed without being opened.

Therefore, the structure shown in FIG.
A liquid cutoff valve 121 in which a float 122 and a valve body 123 on the upper part of the float 122 are relatively movable is disclosed.
-112658.

The valve body 123 of the liquid cutoff valve 121
Comes into contact with the valve seat portion 110b and is discharged through the discharge path 103.
And a second seal portion 123b that abuts on the upper surface 122a of the float 122.

The second seal portion 123b has an opening area smaller than that of the first seal portion 123a, and the valve body 12
A communication hole 123c that communicates the first seal portion 123a and the second seal portion 123b is formed in 3.

In the normal state, the liquid cutoff valve 121 has a float 122 and a valve body 123 located below as shown in FIG. 8A so that the fuel vapor G101 in the fuel tank floats from the communication hole 112. Room 110
The first seal portion 1 in a valve opened state by communicating the gap inside a
It is discharged to the discharge path 103 via 23a.

Then, as shown in FIG. 8B, the float chamber 11
When the fuel L101 flows into the inside of 0a, the float 122
Moves upward so that the valve body 123 is also pushed up by the buoyancy and closes the first seal portion 123a and the second seal portion 123b. Therefore, in this state, the fuel L1
01 does not leak to the discharge path 103 from any of the seal portions.

Next, the fuel L101 in the float chamber 110a
8C, the float 122 first moves downward, as shown in FIG. 8C. Float 1 at this time
Since 22 is in contact with the second seal portion 123b having a small opening area with respect to the valve body 123, even when the pressure inside the fuel tank 101 is high, upward pressure is generated in the float 122 due to the pressure difference from the discharge path side. The biasing force is extremely small, and the weight of the float 122 causes the second seal portion 123b to
To open the valve easily.

In the state of FIG. 8 (c), the fuel vapor G101 inside the fuel tank 101 is generated on the upper surface side and the lower surface side of the valve body 123 by communicating the fuel vapor G101 from the communication hole 123c to the discharge path 103 side. The pressure difference is eliminated, and the first seal portion 123a is also opened to move it downward.

Further, 123d is a valve guide which engages with the engaging portion 122b of the float 122, and the valve body 12
3 and the float 122 can be moved relative to each other within a certain range in the vertical direction. In the state of FIG. 8C, the float 122 hangs on the valve body 123, and the weight of the float 122 is loaded on the valve body 123 when the water level of the fuel L101 in the float chamber 110a drops. It assists the valve opening of the seal portion 123a.

[0017]

In the prior art liquid cutoff valve 121 of FIG. 8 configured as described above, the fuel returns from the float chamber to the fuel tank when compared with the liquid cutoff valve 101 of FIG. 7. When the float 122 is moved, the downward movement of the float 122 itself is performed quickly.

However, in the valve body 123, the valve seat portion 110b is kept until the fuel vapor in the fuel tank flows out from the small-diameter communication hole 123c to the discharge path 103 side and the pressure inside the fuel tank is reduced to eliminate the pressure difference. However, there is a problem that the valve opening response of the first seal portion 123a is low because it takes time to open the first seal portion 123a (the state of FIG. 8A).

Further, in the liquid cutoff valve 121 of FIG. 8, the valve body 123 and the float 122 need to move relative to each other as movable bodies in a separate structure, and moreover, they must be engaged in a fixed relationship. However, in order to achieve a reliable operation, more precise parts and assembly precision were required.

The present invention was made in order to solve the above-mentioned problems of the prior art. The object of the present invention is to discharge gas at a large flow rate and to have a high valve opening response and a simple structure. And to provide a highly reliable liquid cutoff valve.

[0021]

In order to achieve the above object, according to the present invention, a float chamber for accommodating a float therein is provided at the upper part of a sealed container for accommodating a liquid, and this float chamber. A liquid provided with an opening connection part of a discharge path for discharging the gas generated in the sealed container at the upper part of the above, and a valve for opening and closing the opening connection part by a float that moves by generating buoyancy by the liquid flowing into the float chamber In a shutoff valve, the valve is a first valve formed around the opening connection.
First valve having a valve seat portion and a first valve body portion provided in the float that abuts against the first valve seat portion, and pressure introduction for introducing the pressure of gas inside the sealed container. A second valve seat portion connected to the path, and a second valve seat portion formed in a region surrounded by the first valve seat portion of the first valve body portion that abuts against the second valve seat portion.
And a second valve that opens and closes at substantially the same time as the first valve is moved by the movement of the float.

Therefore, the first valve and the second valve prevent the liquid from leaking to the discharge path by moving the float and closing the valve almost at the same time when the liquid flows into the float chamber. Further, at the time of opening the valve when the water level of the liquid in the float chamber is lowered, the biasing force in the valve closing direction due to the pressure difference between the discharge passage and the gas inside the sealed container, which is applied to the closed first valve Since the pressure is canceled by the gas pressure inside the sealed container applied to the second valve body portion by the path, it is possible to open the valve even when the gas pressure inside the sealed container is high, and the valve opening response is improved.

Further, either the first or the second valve body portion is provided with an elastic lip that abuts on the valve seat, and the valve body portion having the elastic lip abuts on the valve seat and closes the valve, It is also preferable that the other valve body is closed by the bending of the elastic lip. According to this, the permissible range of the opening / closing timing difference between the first valve and the second valve can be increased to be equal to or less than the bending amount of the elastic lip, and the operation reliability of the liquid cutoff valve is improved.

Further, it is also preferable that the pressure introducing path connects the second valve seat portion and the float chamber.

According to this, in the valve closed state in which the liquid flows into the float chamber, the amount of gas acting on the second valve body is extremely small, and the stable valve closed state is maintained.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on the illustrated embodiments.

(Embodiment 1) The liquid cutoff valve 1 according to the first embodiment of the present invention is mounted as a hermetically sealed container on the upper portion of a fuel tank of, for example, an automobile, as in the case of the prior art. Normally, fuel vapor or the like (G1) as a gas is discharged from the discharge path connected to the liquid cutoff valve 1, but for example, the vehicle shakes and the liquid fuel (L1) is discharged.
It functions to prevent the liquid fuel from leaking to the discharge path when the water level in 1) rises or the vehicle leans or falls.

FIG. 1 is a diagram for explaining a characteristic structure of a liquid cutoff valve 1 to which the present invention is applied. FIG. 1A is a sectional structure explanatory view, and FIG. 1B is a perspective view of a valve 13. 1C is an enlarged cross-sectional explanatory view of the valve 13.

The main structure of the liquid cutoff valve 1 will be described with reference to FIG. A lower body 2 has a float chamber 2a inside, and a flange portion 2b is attached to an upper wall T1 of the fuel tank via a gasket 3. Reference numeral 4 is a cover plate that covers the flange portion 2b.

An upper body 5 forming an upper end surface of the float chamber 2a is hermetically connected to the upper end portion of the lower body 2 by an O-ring 6, and a lower end portion of the lower body 2 forms a lower end surface of the float chamber 2a. 7 is attached.

Further, the upper body 5 is provided with a discharge passage 9 for discharging the fuel vapor in the fuel tank through the opening connection portion 8 so as to be connected to the float chamber 2a. The discharge path 9 is formed from the nipple 9a by a discharge pipe not shown in FIG.
Connected to a canister similar to that shown in. Reference numeral 10 is a plug for sealing the upper portion of the upper body 5.

The cap 7 is provided with a predetermined number of communication holes 7a for communicating the float chamber 2a with the inside of the fuel tank.

Reference numeral 11 denotes a float accommodated in the float chamber 2a of the lower body 2, and a buoyancy force is generated by the fuel L1 flowing into the float chamber 2a from the communication hole 7a to move upward in the state shown in this figure. 12 is float 1
It is a spring that adjusts the buoyancy of 1a and that also functions as a biasing means for biasing a valve 13 (described later) provided in the float 11a in a closing direction even when the posture of the float 11a is inclined or inverted.

The opening connecting portion 8 has a float chamber 2a around it.
The first valve seat portion 8a is provided on the side. And
The valve 13 that enters the opening of the opening connecting portion 8 has the float 1
It is provided on the upper part of 1a.

The valve 13 is shown in a perspective view in FIG. 1 (b). The valve 13 has a configuration that functions as two valves, a first valve V1 and a second valve V2.

The first valve V1 includes a first valve seat portion 8
a and a seal lip 14 made of an elastic material as a first valve body portion that abuts on the valve seat portion 8a.

Further, the second valve V2 has a columnar portion 13 projecting in a region surrounded by the seal lip 14 as a second valve body portion.
It is composed of a part of the spherical top surface portion 13b of a (a shaded area in FIG. 1B) and the second valve seat portion 15a.

However, the second valve seat portion 15a comes into contact with the top surface portion 13b, and the float chamber 2a.
From the fuel vapor G1 inside the fuel tank through the communication hole 5a
Bypass path 1 as a pressure introduction path for introducing the pressure of
Connected to 5.

FIG. 1 (c) is an enlarged view of a region near the valve 13, showing a state in which the valve 13 is fitted in the opening connecting portion 8 (the first and second valves V1 and V2 are closed). The state in which the first and second valves V1 and V2 are connected is specifically described.

The size of the valve area of the first valve V1 is the diameter D1.
The size of the valve area of the second valve V2 is obtained from D2, and in this embodiment, D1> D2.
And have a relationship. The seal lip 14 is slightly bent when both the first and second valves V1 and V2 are closed.

Due to the bending of the seal lip 14, it is possible to increase the allowable range of deviation of the opening and closing timings of the first and second valves V1 and V2, which are opened and closed at substantially the same time, to the lip bending amount or less.

Next, the operation of the liquid cutoff valve 1 will be described. The liquid cutoff valve 1 has a fuel L1 inside the float chamber 2a.
In the normal state in which the gas does not flow in, the fuel vapor G1 inside the fuel tank is discharged from the float chamber 2a to the discharge path 9 through the opening connection portion 8 (state of FIG. 1A).

Then, when the fuel L1 flows into the float chamber 2a when the water level of the fuel L1 rises, tilts or falls, for example when the vehicle shakes, buoyancy is generated in the float 11 and is shown in FIG. It will be in the state of moving upward.

In the state shown in FIG. 2, the opening connecting portion 8 has the valve 13
Is closed by the first and second valves V
Both 1 and V2 are in the closed state. In this state, the fuel L1 is prevented from leaking to the discharge route 9.

Here, the bypass path is connected to the float chamber 2a in the valve closed state in which the fuel L1 is flowing into the float chamber 2a, and the top surface portion 1 which is the second valve body portion.
This is because the amount of the fuel G1 acting on 3b is an extremely small amount because it is the space volume between the float 11 and the float 11 in the upper part of the float chamber 2a, so that a stable valve closed state is maintained.

FIG. 3 is a diagram showing a state when the fuel L1 in the float chamber 2a returns to the fuel tank and the water level drops, and FIG. 3 (a) shows the liquid cutoff valve 1 in that state. 3B is an enlarged view of the vicinity of the valve 13. FIG.

When the fuel L1 does not exist in the float chamber 2a, the fuel vapor G1 enters from the fuel tank into the inside of the float chamber 2a and flows into the bypass passage 15 through the communication hole 5a and the valve of the second valve V2. Pressure is applied to the top surface portion 13b which is the body portion.

Therefore, the pressure receiving area that the valve 13 receives when the valve is opened is equal to the valve area of the first valve V1 minus the valve area of the second valve V2, so that the restart valve pressure can be set high. You can

That is, the biasing force in the valve closing direction due to the pressure difference between the discharge path 9 applied to the first valve V1 in the valve closed state and the fuel vapor G1 inside the fuel tank is changed by the pressure applied to the top surface portion 13b by the bypass path 15. It cancels out and falls, and it becomes possible to open the valve 13 even when the gas pressure inside the sealed container is high.

As shown in FIG. 1C, the seal lip 14
In the case where the valve 13 is closed while the valve is bent, the second valve V2 is opened as shown in FIG. 3 (b) as the first stage when the valve is opened. There may be a state in which the first valve V1 is closed for a short time.

In this state, the biasing force in the valve closing direction due to the pressure difference generated in the first valve body portion V1 overcomes the force of moving downward due to the weight of the float 11 or the like. However, the opening of the second valve V2 causes the fuel vapor G1 to flow out to the discharge path 9 and the pressure difference is eliminated, so that the first valve V1 is also quickly opened.

The valve area of the second valve V2 is shown in FIG. 1 (c).
As described above, it is possible to set at a ratio that is considerably larger than the opening area of the opening connection portion 8, and the second valve V2 is opened but the first valve V1 is closed. The fuel vapor G1 is smoothly discharged while the fuel vapor G1 is being discharged.

The conditions for closing the liquid cutoff valve 1 will be described with reference to FIG. FIG. 4A shows a state in which the water level of the fuel L1 inside the fuel tank has reached the float chamber 2a due to vehicle sway or the like.
3 is closed.

FIG. 4 (b) shows a state in which the fuel tank is tilted. The force that moves in the valve closing direction due to the buoyancy of the float 11 decreases in accordance with the tilted angle, but the spring 12 closing direction. The valve 13 is closed by the biasing force of.

FIG. 4 (c) shows a state in which the vehicle or the like falls, and the float chamber 2a is filled with the fuel L1. By setting the urging force of the spring 12 to be larger than the buoyancy of the float 11, the float 11 is urged in the valve closing direction (the lower side in the case of FIG. 4C) and the valve 13 is pressed.
Close the valve.

Therefore, as described above, as shown in FIG.
In any of the states (b) and (c), the fuel L1 does not leak to the discharge path 9.

(Second Embodiment) FIG. 5 shows a second embodiment in which the configuration of the valve 13 of the first embodiment is changed. Since the other configurations are the same as those described in the first embodiment, the description thereof will be omitted.

The valve 23 shown in FIG. 5A is in a closed state, and a gasket portion 24 serving as the valve body portion of the first valve is provided on the upper surface of the float 11, and a second valve is provided at the center of the gasket portion 24. The hemispherical protruding portion 25 serving as the valve body is integrally molded of a rubber-like elastic material. Reference numeral 26 is a first valve seat portion corresponding to the gasket portion 24, and 27 is a second valve seat portion corresponding to the protruding portion 25.

The feature of this embodiment is that the valve 23 has substantially the same function as the valve 13 according to the first embodiment, but the axial dimension is shortened, and the gasket portion 24 is reduced.
It is possible to integrally form the hemispherical projection 25 and the valve 23 with a simple structure.

The valve 33 of FIG. 5 (b) is flat as the second valve body portion, whereas the first embodiment has the spherical top surface portion 13b as the second valve body portion. A top surface portion 34 and a second valve seat 35 corresponding to the top surface portion 34.

In this embodiment, since the top surface portion 34 and the valve seat 35 are in planar contact with each other, even if the top surface portion 34 is deformed by contacting with high pressure, the top surface portion 34 and the valve seat 35 are closely fitted. There is no match.

In the valve 43 of FIG. 5 (c), the first valve body portion and the second valve body portion are constituted by one gasket 44. In this embodiment, the opening area of the opening connection portion is limited by the second valve seat 45, but the structure of the valve body portion is extremely simple and the reliability is improved.

[0063]

According to the present invention described above, when the valve is opened, the discharge path applied to the closed first valve and the valve closing direction due to the pressure difference between the gas inside the sealed container The urging force is offset by the pressure of the gas inside the sealed container that is applied to the second valve body portion by the pressure introduction path, and the valve opening response is improved.

Therefore, it is possible to easily open the first valve even in a state where the gas pressure inside the sealed container is high, and it is necessary to enlarge the first valve in order to increase the flow rate. It is achieved without impairing sex.

Further, the valve bodies of the first valve and the second valve are integrally formed, and the reliability of the liquid cutoff valve is improved by the simple structure.

With the valve body portion having the elastic lip, the allowable range of the opening / closing timing difference between the first valve and the second valve can be increased to less than the bending amount of the elastic lip. Compensation for variations in accuracy and assembly accuracy improves the operational reliability of the liquid cutoff valve.

According to the structure in which the pressure introducing path connects the second valve seat portion and the float chamber, the amount of the gas acting on the second valve body portion in the valve closed state in which the liquid flows into the float chamber is It is an extremely small amount and a stable valve closed state is maintained.

[Brief description of drawings]

FIG. 1 is a diagram of a liquid cutoff valve according to an embodiment of the present invention, in which (a) is a sectional view thereof (b) is a perspective view of a valve 13 and (c) is an enlarged sectional view of the valve 13. Fig.

FIG. 2 is a diagram when the liquid cutoff valve of the present invention is closed.

FIG. 3 is a diagram when the liquid cutoff valve of the present invention is opened.

FIG. 4 is a diagram for explaining a valve closing condition of the liquid cutoff valve according to the present invention.

FIG. 5 is a view showing various variations of the liquid cutoff valve according to the second embodiment of the present invention.

FIG. 6 is a diagram showing an example of use of a conventional liquid cutoff valve.

FIG. 7 is a diagram of a conventional liquid cutoff valve.

FIG. 8 is a view of a conventional liquid cutoff valve.

[Explanation of symbols]

1 Liquid cutoff valve 2 Lower body 2a float chamber 2b Flange part 3 gasket 4 cover plate 5 Upper body 6 O-ring 7 cap 7a communication hole 8 Open connection 8a First valve seat portion 9 discharge routes 10 plugs 11 floats 12 springs 13 valves 13a cylindrical part 13b Top part 14 seal lip 15 Bypass route (pressure introduction route) 15a Second valve seat portion D1, D2 diameter G1 Fuel vapor (gas) L1 fuel (liquid) V1 first valve V2 second valve

Claims (3)

(57) [Claims] 1. A float chamber, which is provided at the upper part of a hermetically-sealed container for containing a liquid, and which houses a float therein,
An opening connection part of a discharge path for discharging the gas generated in the sealed container is provided above the float chamber, and a valve that opens and closes the opening connection part by a float that moves by generating buoyancy by the liquid flowing into the float chamber. In the liquid cutoff valve provided, the valve includes a first valve seat portion formed around an opening connection portion, and a first valve body portion provided in the float that abuts on the first valve seat portion. A first valve having: a second valve seat portion connected to a pressure introducing path for introducing the pressure of the gas inside the sealed container; and the first valve abutting against the second valve seat portion. A second valve body portion formed in a region surrounded by the first valve seat portion of the body portion, the second valve opening and closing at substantially the same time as the first valve by the movement of the float; Liquid shield characterized by having Valve. 2. An elastic lip that abuts a valve seat on either the first or the second valve body portion, and after the valve body portion having the elastic lip abuts the valve seat and closes the valve, The liquid cutoff valve according to claim 1, wherein the other valve body is closed by the bending of the elastic lip. 3. The liquid cutoff valve according to claim 1, wherein the pressure introduction path connects the second valve seat portion and the float chamber.