JP2003139002A - Fuel shut-off valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel shut-off valve 20 for preventing the flow of a fuel to the outside even in the case of receiving great transversal waves or push-up waves while turning a vehicle. SOLUTION: The fuel shut-off valve 20 comprises a casing body 30, a first float 40 formed with its specific gravity smaller than that of the fuel, a second float 52 formed with its specific gravity larger than that of the fuel, and a spring 56 for energizing the second float 52 to the direction of a second connection passage 46d. The first float 40 moves up with buoyancy to close a first connection passage 32d when a fuel liquid level in a fuel tank FT exceeds a first liquid level FL1. The second float 52 moves up with buoyancy to close the second connection passage 46d when the fuel liquid level exceeds a second liquid level FL2 higher than the first liquid level FL1, and it moves down to open the second connection passage 46d before the fuel liquid level is lower than the second liquid level FL2 and lower than the first liquid level FL1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cutoff valve which is mounted on an upper portion of a fuel tank and cuts off the communication between the fuel tank and the outside according to the fuel level in the fuel tank.

[0002]

2. Description of the Related Art Conventionally, as a fuel cutoff valve of this type, for example, the technique disclosed in Japanese Patent Laid-Open No. 6-297968 is known. That is, the conventional fuel cutoff valve includes a casing having a connection passage connected to the outside of the fuel tank, a cylindrical first float valve arranged in a valve chamber in the casing, and a first float valve in the first float valve. The second, which can be moved up and down in the storage room
It is equipped with float valves and springs that support them,
When the fuel level exceeds the first level, the first float valve closes the connection passage, and when the fuel level exceeds the second level, the second float valve closes the connection passage. This prevents the fuel from flowing out of the fuel tank to the canister when refueling or when the vehicle swings.

[0003]

However, in the above fuel cutoff valve, since the first and second float valves made of a material having a larger specific gravity than the fuel liquid are moved up and down by the spring, the float valve has a rising speed. Cannot follow the rising speed of the fuel level. For this reason, it has not been possible to sufficiently prevent the outflow of fuel by quickly closing a large transverse wave or a wave that pushes up when the vehicle turns.

The present invention solves the above-mentioned problems of the prior art. It closes quickly even when it receives a large transverse wave generated when the vehicle turns, or a wave that pushes up from below, and goes outside the fuel tank. An object of the present invention is to provide a fuel cutoff valve that does not allow fuel to flow out.

[0005]

Means for Solving the Problems and Their Actions / Effects The present invention, which has been made to solve the above problems, is mounted on the upper portion of a fuel tank, and is connected to the outside of the fuel tank depending on the fuel level in the fuel tank. In the fuel cutoff valve that shuts off the communication,
A casing provided with a casing body forming a valve chamber communicating with the inside of the fuel tank, an external passage arranged outside the fuel tank, and a first connection passage connecting the external passage and the valve chamber, and the valve described above. Has a storage chamber that is vertically movable in the chamber and has a lower opening, and a second connection passage that connects the first connection passage and the storage chamber and has a flow passage area narrower than that of the first connection passage. And a second float formed in a storage chamber so as to be able to move up and down, open and close the second connecting passage, and have a specific gravity larger than that of the fuel.
The first float includes a float and a spring that biases the second float toward the second connection passage, and the first float is lifted by buoyancy when the fuel level in the fuel tank exceeds the first level. Is configured to close the first connection passage,
The second float has a second liquid level higher than the first liquid level.
When the liquid level is exceeded, it rises due to buoyancy to close the second connecting passage, and it descends before the fuel liquid level is lower than the second liquid level and lower than the first liquid level to open the second connecting passage. It is characterized by having been constituted.

In the fuel cutoff valve according to the present invention, when the fuel liquid level in the fuel tank is lower than the first liquid level during refueling, the fuel cutoff valve communicates with the outside (canister) side to let the fuel vapor in the fuel tank escape to the outside. On the other hand, when the fuel level in the fuel tank exceeds the first level, the first float floats and closes the first connection passage, temporarily increasing the pressure in the fuel tank and automatically stopping the refueling gun. Prompt and prevent the fuel in the fuel tank from flowing out.

At this time, the second connecting passage remains open through a passage having a smaller flow passage area than the first connecting passage,
The inside of the fuel tank is connected to the outside. Thus, even if the pressure inside the fuel tank rises or falls when the first float is closed, the tank internal pressure is adjusted by ventilating the outside. Further, when the fuel liquid level exceeds the second liquid level higher than the first liquid level when the vehicle rolls over or leans, the second float floats and closes the second connection passage.

In the fuel cutoff valve according to the present invention, the first
Since the float is formed smaller than the specific gravity of the fuel,
When the liquid level of the fuel rapidly rises when the liquid level fluctuates when the vehicle turns, it is possible to follow the rising speed of the fuel level.
The connection passage can be closed promptly.

Further, since the second float has a larger specific gravity than the fuel, when the fuel level falls below the second level, the second float quickly separates from the first float. Therefore, the pressure difference between the inside and the outside of the fuel tank is promptly eliminated, so that the light-weight first float does not stick to the seat of the first connection passage, and excellent reopening valve characteristics can be obtained.

Further, when the vehicle rolls over or falls, the first float is pushed by the second float having a large specific gravity,
Since the first connection passage is closed by being submerged or the like and the first float is closed, the fuel in the fuel tank does not flow out.

Further, as a preferred mode, the storage chamber can be configured to communicate with the valve chamber through a narrow passage provided in an upper portion of the first float. With this configuration, the narrow passage is provided on the upper part of the first float,
If the liquid level of the fuel does not reach the upper part of the float, the fuel does not flow into the storage chamber, so that the fuel can be prevented from flowing out through the first and second connecting passages.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described below in order to further clarify the constitution and operation of the present invention described above.

(1) Schematic Structure of Fuel Cutoff Valve 20 FIG. 1 is a sectional view showing a fuel cutoff valve 20 mounted on an upper portion of a fuel tank FT of an automobile according to an embodiment of the present invention. In FIG. 1, the fuel tank FT has a surface formed of a composite resin material containing polyethylene, and a mounting hole FTc is formed in the tank upper wall FTa. The fuel cutoff valve 20 is attached to the tank upper wall FTa with its lower portion protruding into the attachment hole FTc.

The fuel cutoff valve 20 is a valve for restricting the outflow of fuel to the outside (canister) when the fuel in the fuel tank FT rises to a predetermined liquid level during refueling or the like. Here, the predetermined liquid level means a first liquid level FL1 which means that the fuel is full at the time of refueling, and a first liquid level FL1 which is higher than the first liquid level FL1 which regulates the outflow of fuel when the vehicle is tilted. It is a two-level FL2. Hereinafter, the configuration and operation of each part of the fuel cutoff valve 20 will be described.

The fuel cutoff valve 20 includes a casing body 30.
, Bottom plate 35, first float 40, second float 5
2, a spring 56, and a lid 60 are provided as main components. The casing body 30, the bottom plate 35, and the second float 52 constituting the rollover valve 50 are made of synthetic resin polyacetal having excellent fuel oil resistance. The first float 40 is made of a material having a specific gravity smaller than that of the fuel, as will be described later. FIG. 2 shows a fuel cutoff valve 2
It is sectional drawing which decomposes | disassembles and shows 0.

(2) Casing main body 30 The casing main body 30 includes a ceiling wall portion 32 having a flange 32a and a side wall portion 33 extending downward from the ceiling wall portion 32 in a cylindrical shape. 32 and side wall 3
A cup-shaped valve chamber 30S surrounded by 3 is formed, and the lower portion thereof is a lower opening 30a. A first connecting passage 32b penetrates through the central portion of the ceiling wall portion 32, and the valve chamber 30S side of the first connecting passage 32b is a first seat portion 32d.

The first communication hole 3 is formed in the upper portion of the side wall portion 33.
3a is formed, and the second communication hole 33b is formed in the lower part thereof. The 1st communicating hole 33a is the 1st float 40 when the 1st float 40 shown in FIG. 1 is located below.
Is located above the upper surface of the first float 40 and is formed so that the first float 40 is not pushed up by the airflow flowing from the first communication hole 33a. The second communication hole 33b is a hole that communicates with the valve chamber 30S and allows the fuel to flow into the valve chamber 30S. In addition, the lower part of the side wall portion 33 has an engaging claw 33c.
Are formed. The engagement claw 33c is for attaching the bottom plate 35 as described later.

(3) Bottom Plate 35 The bottom plate 35 is a member that closes the lower opening 30a of the casing body 30, and the engagement hole 35 formed in the outer peripheral portion thereof.
By engaging the engaging claw 33c with a, the casing body 30 is mounted so as to close the lower opening 30a.
In addition, the spring support portion 35 is provided on the central upper surface of the bottom plate 35.
c is projected in a cylindrical shape. This spring support 3
5c supports the spring 56 between itself and the inner recess of the second float 52. A cylindrical bent wall 35d is formed on the outer periphery of the bottom plate 35. The folding wall 35d is
As shown in FIG. 1, it is arranged at a position facing the second communication hole 33b, and an air passage 35e is secured between it and the side wall portion 33. Therefore, when fuel vapor flows through the air passage 35e and the second communication hole 33b during refueling, the air flow is diverted,
The force that pushes up the first float 40 is reduced.

(4) First Float 40 In FIG. 2, the first float 40 is a container having an upper wall portion 41 and a cylindrical side wall portion 42 formed below the outer periphery of the upper wall portion 41. A storage chamber 40 configured to have a shape and an inner space for storing the second float 52.
It is S. In addition, the guide ridge 40a is formed on the outer peripheral portion of the first float 40, and the casing main body 30
Is guided by the side wall portion 33 of the. First float 40
Is a butadiene-acrylonitrile copolymer (NBR)
Is independently foamed, and its surface is formed into a hard skin layer, and the specific gravity is 0.2 to 0.4.
It is lighter than fuel.

A through hole 41a is formed at the center of the upper wall portion 41, and a rubber valve element 46 is projected into and supported by the through hole 41a. FIG. 3 shows the rubber valve element 46 on the first float 40.
It is explanatory drawing explaining the state before attaching. The rubber valve body 46 includes a disc-shaped seat portion 46a and a seat portion 46a.
A support portion 46b protruding from the lower part of the is integrally formed of rubber. On the other hand, an engaging portion 41b for supporting the rubber valve body 46 is formed around the through hole 41a of the upper wall portion 41, and a narrow passage 41c is formed between the engaging portions 41b. The rubber valve body 46 is mounted on the upper portion of the first float 40 by the support portion 46b engaging with the engaging portion 41b. In this mounted state, the narrow passage 41c communicates the valve chamber 30S with the storage chamber 40S. The upper surface of the rubber valve body 46 is a seating surface 46c, which is attached to and detached from the first seat portion 32d (see FIG. 2) when the first float 40 is moved up and down. Also,
A second connection passage 46d is formed in the center of the rubber valve body 46, and communicates the storage chamber 40S and the first connection passage 32b.

(5) Second Float 52 In FIG. 2, the second float 52 has a seat surface 5 on its upper surface.
It is formed in a cylindrical shape having 2a, and is provided with an open buoyancy chamber 52S at the lower part thereof. A guide protrusion 52b is formed on the outer periphery of the second float 52, and is guided by the wall of the storage chamber 40S of the first float 40 by the guide protrusion 52b. A spring support recess 52c is formed in the upper part of the buoyancy chamber 52S, and the upper part of the spring 56 is supported in the spring support recess 52c.
The second float 52 is supported by the bottom plate 35. The second float 52 is made of polyacetal having a larger specific gravity than the fuel.

(6) Lid body 60 The lid body 60 includes a lid body 61, a tube portion 62 projecting from the center of the lid body 61 to an upper portion in an L shape, and a flange 63 formed on the outer periphery of the lid body 61. , And these are integrally formed. A lid fitting portion 61 for fitting the flange 32a of the casing body 30 is provided at the center of the lower portion of the lid body 61.
a is formed. A lid side passage 62a is formed in the tubular body portion 62, one end of the lid side passage 62a is connected to the first connection passage 32b of the casing body 30, and the other end is connected to the canister side. ing. Further, an annular welded portion 63a is formed at the lower end of the flange 63. The lid 60 is made of polyethylene having excellent fuel oil resistance, and is welded to the upper portion of the fuel tank FT made of the same polyethylene at the annular welding portion 63a.

(7) Operation of Fuel Cutoff Valve 20 During Refueling Next, the operation of the fuel cutoff valve 20 will be described. When the fuel is supplied to the fuel tank FT by the fuel gun (not shown) from the opened state of the fuel cutoff valve 20 shown in FIG. 4, the fuel vapor accumulated in the upper portion of the fuel tank FT becomes the fuel in the fuel tank FT. As the liquid level rises, the first communication hole 33a of the side wall portion 33, the valve chamber 30S, the first connection passage 32b, and the second communication hole 33b, the valve chamber 30S, the first connection passage 32b to the canister side through the lid side passage 62a. Escaped.
At this time, the first communication hole 33a is arranged above the upper surface of the first float 40 in the state of FIG.
The airflow flowing in from the connection passage 32b is the first float 40
Does not act as a force to close the first float 40. Further, since the bent wall 35d is formed on the outer peripheral side of the second communication hole 33b, the second communication hole 3b is formed.
The airflow flowing into 3b bypasses the air passage 35e and is weakened, and the force for raising the first float 40 is small. Therefore, the first float 40 does not unexpectedly close due to the air flow during refueling.

As the fuel liquid level in the fuel tank FT rises, as shown in FIG. 5, the liquid fuel flows into the second communication hole 3
3b into the valve chamber 30S, and the first float 40
Increase the buoyancy of. The fuel level is the first level FL
When it exceeds 1, the first float 40 rises and the rubber valve body 4
At 6 the first connection passage 32b is closed. First connection passage 32
Since the pressure in the fuel tank FT rises due to the blockage of b, the refueling gun detects the pressure and stops refueling.
In this way, the fuel cutoff valve 20 allows the fuel vapor to escape from the fuel tank FT and prevents the liquid fuel from flowing out of the fuel tank FT when fueling the fuel tank FT.

At this time, the second float 52 of the rollover valve 50 does not rise because the upward force of the buoyancy and the spring 56 does not exceed the weight of the second float 52, and the second connection passage 46d does not rise. Remains open. Therefore, the inside of the fuel tank FT is connected to the canister side through the first communication hole 33a, the upper portion of the valve chamber 30S, the narrow passage 41c (see FIG. 3) on the outer periphery of the rubber valve body 46, the storage chamber 40S, and the second connection passage 46d. Has been done. At this time, the narrow passage 41
Since c is a narrow flow passage area, the outflow of fuel on the canister side can be suppressed even at a fuel liquid level close to full.

Further, continue refueling from the refueling gun,
As shown in FIG. 6, when the fuel liquid level of the fuel tank FT rises to the second liquid level FL2, the valve chamber 30S and the storage chamber 40
The second float 52 rises due to the fuel that has entered the lower portion of S, the seat surface 52a is seated on the seat surface 46f of the rubber valve body 46, and the second connection passage 46d is closed. In this way, the rollover valve 50 closes the second connection passage 46d to prevent the fuel from flowing out to the canister when the second liquid level FL2 that exceeds the first liquid level FL1 is reached.

On the other hand, when the fuel in the fuel tank FT is consumed or the inclination of the vehicle is eliminated and the liquid level of the fuel drops, the second float 52 decreases its buoyancy and descends to the second connection. The passage 46d is opened (state from FIG. 6 to FIG. 5). At this time, the second float 52 has a large weight, and since air is not introduced into the storage chamber 40S through the narrow passage 41c and a negative pressure is not generated, the second float 52 quickly descends to open the second connection passage 46d. Due to the communication of the second connection passage 46d, the inside of the storage chamber 40S has the same pressure as the vicinity of the first connection passage 32b through the second connection passage 46d. Since the pressure difference is reduced, the force with which the rubber valve element 46 is brought into close contact with the first seat portion 32d is weakened, so that the first float 4
0 descends smoothly (state of FIG. 4). As described above, the second float 52 functions not only as the rollover valve 50 but also as a function of promoting the improvement of the reopening valve characteristic for smoothly opening the first float 40.

(8) The operating fuel liquid level of the fuel cutoff valve 20 when the vehicle swings is near the first liquid level FL1, and when the vehicle swings, the liquid level in the fuel tank FT swings. At this time, the first float 40 has a specific gravity of 0.
Because it is light weight of 2 to 0.4, it is greatly affected by buoyancy,
Moreover, since the frictional force generated by the force pressed against the inner wall of the casing main body 30 is small, the frictional force rises quickly and the first
The connection passage 32b is closed. Therefore, it is possible to prevent the fuel from flowing out during rocking.

(9) Operation of the fuel cutoff valve 20 when the vehicle rolls over When the vehicle rolls over, as shown in FIG.
Turns sideways and submerges. At this time, the second float 5
Since No. 2 gains buoyancy and becomes lighter, it moves to the left side in the figure by the urging force of the spring 56, and pushes the first float 40 to move it in the same direction. This allows the second
The seat surface 52a of the float 52 is seated on the seat surface 46f to close the second connection passage 46d. Therefore, it is possible to prevent the fuel from flowing out when the vehicle rolls over.

(10) Operation of the fuel cutoff valve 20 when the vehicle falls over When the vehicle falls, as shown in FIG.
Turns upside down and submerges. At this time, the second float 5
In No. 2, since the specific gravity is heavier than the fuel, the fuel sinks and sinks the first float 40 downward. As a result, the second float 5
The second seat surface 52a is seated on the seat surface 46f to close the second connection passage 46d. Therefore, it is possible to prevent the fuel from flowing out at the time of falling.

(11) Effects of the fuel cutoff valve 20 Since the specific gravity of the first float 40 is much smaller than that of the fuel, when the liquid level of the fuel rises rapidly when the liquid level fluctuates during turning of the vehicle, The rising speed of the fuel liquid level can be followed, and the first connection passage 32b can be closed quickly.

Since the second float 52 has a larger specific gravity than the fuel and does not receive a negative pressure in the storage chamber 40S, when the fuel level falls below the second level FL2, the first float 40 Quickly leave from. Therefore, the pressure difference between the inside and the outside of the fuel tank is promptly eliminated, so that the light-weight first float 40 does not stick to the first seat portion 32d, and excellent reopening characteristics can be obtained.

When the vehicle rolls over or falls, the first
Since the first connecting passage 32b and the second connecting passage 46d are closed by pushing or sinking the float 40 with the second float 52 having a large specific gravity, the fuel in the fuel tank does not flow out.

Since the first float 40 is formed of a closed-cell foam, it retains high mechanical strength against a large external force when the vehicle falls.

The present invention is not limited to the above-mentioned embodiments, but can be carried out in various modes without departing from the scope of the invention, and the following modifications can be made.

(1) In the above embodiment, the first float is formed of foam, but the present invention is not limited to this, and it may be formed of a hollow body in consideration of impact resistance when the vehicle falls. .

(2) In the above embodiment, the case where the structure such as the second float is applied to the rollover valve for preventing the outflow of fuel when the vehicle rolls over or tilts is described, but the invention is not limited to this. It may be applied to a super-lubrication prevention valve that prevents super-lubrication by setting the second liquid level to the full liquid level.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a fuel cutoff valve 20 attached to an upper portion of a fuel tank FT of an automobile according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an exploded view of a fuel cutoff valve 20.

FIG. 3 is an explanatory diagram illustrating a state before the rubber valve body 46 is assembled to the first float 40.

FIG. 4 is an explanatory diagram for explaining a fuel cutoff valve 20 during refueling.

FIG. 5 is an explanatory diagram illustrating an operation of the fuel cutoff valve 20 when the fuel liquid level exceeds the first liquid level FL1.

FIG. 6 is an explanatory diagram illustrating an operation of the fuel cutoff valve 20 when the fuel level exceeds the second liquid level FL2.

FIG. 7 is an explanatory diagram illustrating an operation of the fuel cutoff valve 20 when the vehicle rolls over.

FIG. 8 is an explanatory diagram illustrating an operation of the fuel cutoff valve 20 when the vehicle falls.

[Explanation of symbols]

20 ... Fuel cutoff valve 30 ... Casing body 30S ... valve chamber 30a ... Lower opening 32 ... Ceiling wall 32a ... flange 32b ... first connecting passage 32d ... 1st seat part 33 ... Side wall 33a ... first communication hole 33b ... Second communication hole 33c ... engaging claw 35 ... Bottom plate 35a ... Engagement hole 35c ... Spring support 35d ... Bent wall 35e ... Ventilation path 40 ... First float 40S ... storage room 40a ... Guide ridge 41 ... Upper wall 41a ... through hole 41b ... Engagement part 41c ... narrow passage 42 ... Side wall 46 ... Rubber valve body 46a ... Seat section 46b ... Support section 46c ... seat surface 46d ... second connecting passage 46f ... Seat surface 50 ... Rollover valve 52 ... Second float 52S ... buoyancy chamber 52a ... seat surface 52b ... Guide ridge 52c ... Spring support recess 56 ... Spring 60 ... Lid 61 ... Lid body 61a ... Lid fitting part 62 ... Tube 62a ... lid side passage 63 ... Flange 63a ... Annular weld FL1 ... first liquid level FL2 ... second liquid level FT ... Fuel tank FTa ... tank top wall FTc ... Mounting hole

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Koji Miwa             1 Toyota Town, Toyota City, Aichi Prefecture Toyota Auto             Car Co., Ltd. (72) Inventor Takashi Ishikawa             1 Toyota Town, Toyota City, Aichi Prefecture Toyota Auto             Car Co., Ltd. F-term (reference) 3D038 CA22 CB01 CC04                 3H055 AA02 AA22 BA04 BA12 CC20                       CC21 GG01 JJ03 JJ04 JJ05                       JJ08

Claims (3)

[Claims] 1. A fuel cutoff valve mounted on an upper part of a fuel tank, which cuts off communication between the fuel tank and the outside according to a fuel level in the fuel tank, the casing body forming a valve chamber communicating with the inside of the fuel tank. A casing having an external passage arranged outside the fuel tank, and a first connecting passage connecting the external passage and the valve chamber, and a storage chamber that is vertically movable in the valve chamber and opens downward. And a first float having a second connection passage connecting the first connection passage and the storage chamber and having a flow passage area narrower than that of the first connection passage, and having a specific gravity smaller than that of the fuel; A second float formed to have a specific gravity larger than that of the fuel, and a spring for urging the second float toward the second connection passage. , The first flow The float is configured to rise by buoyancy to close the first connecting passage when the fuel liquid level in the fuel tank exceeds the first liquid level, and the second float has a fuel liquid level of the first liquid level. Second higher than rank
When the liquid level is exceeded, it rises due to buoyancy to close the second connecting passage, and it descends before the fuel liquid level is lower than the second liquid level and lower than the first liquid level to open the second connecting passage. A fuel cutoff valve comprising: 2. The fuel cutoff valve according to claim 1, wherein the first float is formed of a closed-cell foam having fuel resistance. 3. The fuel cutoff valve according to claim 1, wherein the storage chamber is configured to communicate with the valve chamber through a narrow passage provided in an upper portion of the first float.