JPH08291875A - Structure for stop valve - Google Patents

Abstract

PURPOSE: To provide a stop valve in which no blowout of fuel gas from a filler pipe is caused in oil feeding, a sealing property in a valve closing part is improved, and adhesion of a valve element to a valve port is prevented. CONSTITUTION: The first float 13 and the second float 21 are arranged inside a case 12 movably in the vertical direction, and the first valve port 19 and the second valve port 20B are closed by two steps at a certain time interval by means of the two floats 13, 21. As a cross sectional area of the second valve port 20B is small, adhesion of the second valve element 21A is prevented, and as a result, pressures of the inside and the outside of the first valve element 14 are balanced with each other, so that adhesion of the first valve element 14 is also prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stop valve provided in a breathing system of a fuel tank of an automobile internal combustion engine,
More specifically, it relates to an improvement of the stop valve of the float type.

[0002]

2. Description of the Related Art A breathing system communicating with the atmosphere is provided in a fuel tank of an internal combustion engine for an automobile. A canister is provided in the breathing system so that the vaporized gas is not released into the atmosphere as it is. By the way, if the breathing system is constantly open to the atmosphere, the fuel may leak to the outside when the vehicle (fuel tank) is greatly inclined or the vehicle (fuel tank) falls. Therefore, the breathing system of the fuel tank is provided with a stop valve that closes the breathing system when the vehicle tilts or falls. The stop valve is generally a float type valve that floats on the fuel and closes the breathing system depending on the height of the liquid surface of the fuel.

An example of a conventionally known stop valve (see Japanese Patent Application Laid-Open No. 2-112658) will be described below with reference to FIGS. 6 and 7. FIG. 6 is a sectional view showing a conventionally known stop valve,
FIG. 7 is an exploded perspective view of the float shown in FIG.

A float 2 is provided inside the valve casing 1. The float 2 is biased toward the valve port 5 side by a spring 4 provided between the float 2 and the partition wall 3. A breathing port 6 is formed in the valve casing 1, and an inlet portion of the breathing port 6 serves as a valve port 5. The valve body 7 that closes the valve opening 5 is attached to the attachment member 8, and the attachment member 8 is attached to the float 2. A communication hole 9 is provided at the center of the valve body 7, and the communication hole 9 is closed by the recess of the float 2.

The conventionally known stop valve described above operates as follows. The breathing port 6 communicates with the atmosphere via a canister (not shown). Therefore, when the fuel gas flows out by breathing, the fuel gas itself is adsorbed by the canister (not shown) and is not released to the atmosphere. Now, when the fuel tank is greatly inclined, the float 2 floats and the valve body 7 closes the valve opening 5 and at the same time the float 2
Closes the communication hole 9. Therefore, the fuel in the fuel tank 1 does not leak outside through the breathing system. Next, when the inclination of the fuel tank 1 disappears, the float 2 moves downward due to its own weight. what if,
Even if the pressure in the fuel tank 1 is high, since the joint area between the float 2 and the communication hole 9 is small, the blockage of the communication hole 9 by the float 2 is easily released, and as a result, the valve element 7 is acted. The pressure applied is balanced and the blockage of the valve opening 5 by the valve element 7 is released.

In recent years, it has become necessary to increase the breathing ability, and the diameter of the valve opening 5 is increasing. When the area of the valve opening 5 is increased in this way, the diameter of the valve body 7 is also increased and the force in the closing direction acting on the valve opening 5 is also increased. When the internal pressure of the fuel tank becomes large, the force of the closing direction acting on the valve body 7 may prevent the float 2 from falling, and the valve body 7 may be stuck to the valve opening 5. I will end up.

In order to prevent such a situation, in the stop valve having the structure shown in FIGS. 6 and 7, the communication hole 9 is formed at the center of the valve body 7.
Is provided, and the communication hole 9 is closed by the float 2 and at the same time closed by the peripheral edge of the valve body 7, which is a so-called two-point closed structure. That is, as described above, even when the internal pressure of the fuel tank is high, the blockage of the communication hole 9 by the float 2 is easily released, so that the vaporized gas leaks to the breathing side through the communication hole 9, and as a result, the valve is closed. The body 7 also easily separates from the valve opening 5.

On the other hand, since it is necessary to improve the sealing performance of the breathing system, the valve body 7 is usually made of an elastically deformable material such as rubber. On the other hand, when the valve body 7 is made of an elastically deformable material such as rubber, the valve body 7 is deformed and the position of the communication hole 9 becomes uncertain. Therefore, there is a possibility that the communication hole 9 may not be sufficiently closed.

Therefore, in the previously known stop valve, the valve body 7 is once attached to the attachment member 8 and then the attachment member 8 is attached to the float 2, whereby the position of the communication hole 9 formed in the valve body 7 is increased. Is supported so that it does not change much.

[0010]

However, the stop valve provided in the above-mentioned conventionally known breathing system has the following problems. First, when the float 2 rises as the fuel level rises during refueling, the breathing port 6 and the communication hole 9 are closed at the same time, so the evaporative gas in the fuel tank blows out from the filler pipe during refueling. It may end up.

Next, even if the valve body 7 is attached to the attachment member 8, the deformation of the valve body 7 is still not sufficiently prevented, so that the central portion of the valve body 7 is deformed and the communication is established. It is unavoidable that the sealing performance of the holes 9 is deteriorated.

Therefore, an object of the present invention is to improve the above-mentioned drawbacks of the conventionally known stop valve, to prevent the valve body from sticking, to prevent the vaporized gas from being blown out from the filler pipe, and to improve the sealing property of the communication hole. It is to provide the structure of the stop valve.

[0013]

A feature of the present invention is that a case, a first float having a space inside which is vertically movable in the case, and an upper surface of the first float are provided. A first valve body, a first valve opening formed on the upper surface of the case, a first valve seat formed around the first valve opening, and the first valve opening. A breathing passage provided downstream of the valve opening, a second valve opening provided inside the first valve opening, a tubular body partitioning and forming the second valve opening, and the tubular shape A second valve seat and a third valve seat provided at the open end of the body, a through-hole provided at the first valve body, and a through-hole end provided at the first valve body, A third valve portion that opens and closes the third valve seat by the vertical movement of the first valve body, a second float provided inside the first float, and the second float. A second valve body, which is provided on the upper surface of the funnel and opens and closes the second valve seat of the tubular body by vertically moving the through-hole, communicates the inside of the tubular body with the breathing passage. A stop valve provided in the fuel tank, the first float and the second float rising to raise the first valve body when the liquid level of the fuel tank rises. And a third valve portion closing the first valve seat and the third valve seat, and the second valve body of the second float closing the second valve seat, or At the first liquid surface position of the fuel tank, the first float moves upward to move the first valve body and the third valve body.
Valve portion closes the first valve seat and the third valve seat, and the second float of the second float is at a second liquid level position higher than the first liquid level position of the fuel tank. The valve body of the second
The valve seat is closed.

Another feature of the present invention is that the outer peripheral edge of the end portion of the cylindrical body is the third valve seat, and the inner peripheral edge of the end portion of the cylindrical body is the above-mentioned. The second valve seat is formed, and further, the end portion of the cylindrical body is formed of a conical recess.

Further, another feature of the present invention is that
The cylindrical body is provided so as to hang down from the upper surface of the case.

[0016]

According to the present invention, since the breathing passage is closed in two stages in sequence by the first float and the second float, the breathing passage is not suddenly closed and the fuel evaporative gas is not blown out from the filler pipe.

Further, the second float is provided separately from the first float, and the second valve body of the second float closes the second valve seat, so that the second valve seat is not blocked. It will not happen.

Further, since the blockage between the second valve body and the second valve seat is easily released, it is possible to prevent the first valve body from sticking to the valve opening.

[0019]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing the overall structure of a stop valve according to an embodiment of the present invention, and FIG.
FIG. 3 is a sectional view taken along line BB of FIG.

The stop valve 11 of the present invention includes a case 12, a first float 13 provided in the case 12 so as to be vertically movable, and a first float 13 provided on an upper surface of the first float 13.
The valve body 14, the breathing passage 15 provided on the upper surface of the case 12, and the second float 21 provided in the space defined by the interior of the first float.

The case 12 has a cylindrical shape, and a plurality of guide ribs 12A for the float 13 are provided on the inner wall of the case 12. Further, a plurality of through holes 12B are formed through the peripheral surface of the case 12 in order to allow the fuel and the vaporized gas to flow into the case 12. Further, a bottom plate 16 is attached to the lower end of the case 12. Through holes (not shown) are also formed in the bottom plate 16 so that fuel can flow into the lower sides of the first float 13 and the second float 21. A spring accommodating projection wall 16A is circumferentially formed at the center of the bottom plate 16, and a plurality of engagement legs 16B are formed around the bottom plate 16. The engaging leg 16B has a key-like tip, and the key-like tip of the engaging leg 16B is fitted into an engaging hole 12C formed in the case 12, whereby the bottom plate 16 is attached to the case 12. It has become a thing.

The first float 13 has an inverted cup shape, and has a space inside. First float 1
A first valve body 14 is mounted on the upper surface of 3. The first valve body 14 is made of an elastically deformable material such as rubber, and has a through hole 14A vertically penetrating the substantial center thereof. In this embodiment, the first float 13
The first valve body 1 is attached to the mounting portion 13B formed at the center of the
4 is attached, and the through hole 14A is formed at the center of the attaching portion 13B. In addition, the through hole is formed in the valve body itself, and the valve body is provided with the first float 13A. The structure can be attached to the upper surface of the. On the outer peripheral edge of the upper surface of the first float 13, an upwardly extending arc wall-shaped fuel droplet flow prevention wall 13A is formed.

A partition pendant 17 that hangs downward is provided inside the upper surface of the first float 13, and a spring-accommodating protruding wall formed in the space defined by the partition pendant 17 and the bottom plate 16. A spring 18 is housed between the spring 18 and 16A. The spring 18 causes the first float 1 to move in a direction in which the first valve body 14 closes a first valve opening 19 described later.
3 is urged to help the first float 13 float by the fuel, so that the urging force is smaller than the total weight of the first float 13 and the first valve body 14. There is. A third valve portion 14B that closes a third valve seat 20C, which will be described later, is provided near the center of the first valve body 14.

The first valve opening 19 is formed in the center of the upper surface of the case 12, and a first valve seat 19A is formed around the first valve opening 19. A breathing passage 15 is provided downstream of the first valve port 19. A second valve opening 20B is provided at the center of the first valve opening 19. The second valve opening 20B is defined by the lower end of the opening of the tubular body 20 that hangs downward from the upper wall of the case 12. A conical recess 20A is formed on the lower end surface of the tubular body 20.
Is formed, and the outer peripheral edge of the recess is the third valve seat 20C, and the inner peripheral edge of the recess is the second valve seat 20D. The tubular body 20 is provided with a through hole 20E for communicating the inside and the outside. The first valve seat 19A is formed by slightly projecting the peripheral edge of the first valve opening 19 provided in the case 12, which ensures that the first valve body 14 is secured over the entire circumference. It is designed to be seated and have a secure seal.

The cylindrical second float 21 is arranged in the space inside the first float 13, and a second valve body 21A is provided on the upper surface of the second float 21. The second valve body 21A is inserted into the through hole 14A provided in the first valve body 14, and the second float 21 moves up and down to open and close the second valve mouth 20B. . A spring 22 is provided to assist the upward movement of the second float 21.

A fuel droplet outflow prevention plate 23 is provided in the lower half of the breathing passage 15. Since the fuel droplets mainly flow in the lower half of the breathing passage 15,
If the shape of the fuel droplet outflow prevention plate 23 is a half moon shape or a crescent shape, the effect of preventing the fuel droplet outflow is sufficiently exerted. The stop valve 11 configured as described above is the fuel tank 2
It is attached to 4.

The operation of the stop valve of the present invention constructed as above will be described with reference to FIGS. 4 and 5. First, in the steady state, as shown in FIG. 1, the first float 13 and the second float 21 are located below, and the first valve body 1
4 has opened the 1st valve opening 19. Therefore, in the fuel tank 24, the first valve opening 19, the breathing passage 15,
It communicates with the outside air via a canister (not shown).

When the fuel tank 24 tilts or the vehicle falls and the liquid level of the fuel rises, the first float 13 and the second float 21 float in the order shown in FIGS. 4 and 5, respectively. First provided on the float 13
Valve body 14 closes the first valve opening 19 and the second valve body 21
A closes the second valve opening 20B. That is, when the liquid level of the fuel reaches the level indicated by H1, the first float 13 rises and the first valve body 14 closes the first valve opening 19. In this case, since the second float 21 does not float sufficiently, the second valve body 21A does not yet close the second valve opening 20B.
Then, when the liquid level of the fuel further rises to the level indicated by H2, the second float 21 also floats sufficiently high, so that the second valve body 21A closes the second valve opening 20B.

In the changes shown in FIGS. 4 and 5, when the height of the liquid surface of the fuel changes rapidly, the first valve port 19
And the second valve opening 20B are closed almost at the same time,
When the increase in the liquid level of the fuel is slow, such as during refueling,
The first valve body 14 first closes the first valve opening 19 (see FIG.
State), and then the second valve body 21B becomes the second valve opening 20B.
Is closed (state of FIG. 5). Therefore, it is possible to prevent the pressure in the fuel tank from rapidly increasing during refueling, and prevent the fuel from being blown out from the filler pipe.

Now, assume that in the state shown in FIG. 5, the pressure inside the fuel tank becomes high, and the increase in the fuel level due to the inclination of the fuel tank is canceled and the fuel level becomes low. Then, the first valve body 14 is biased by the own weight of the first float 13 in the direction of opening the first valve opening 19, but
Since the inner pressure of the fuel tank 24 acts on the lower surface of the valve body 14, the first valve body 14 is stuck to the first valve port 19. However, since the acting force by the internal pressure of the fuel tank 24 acting on the second valve body 21A is small,
The valve body 21A is easily separated from the second valve seat 20D by the weight of the second float 21 and opens the second valve opening 20B. Then, the evaporative gas in the fuel tank 24 will pass through the through-hole 1
The pressure applied to the breathing passage 15 via 4A, the second valve opening 20B, and the communication opening 20E and acting on the first valve body 14 is balanced. Therefore, the first valve body 14 is
The valve opening 19 of is opened. Therefore, the first valve body 14 does not stick to the first valve opening 19.

Further, returning to FIG. 1 and FIG. 2, as in the case of refueling, the spray of fuel will pass through the valve port 19 and the breathing passage 15
Even if you try to scatter to the
When the fuel splash hits A and the fuel splash outflow prevention plate 23,
Further, the outflow of fuel droplets to the outside is reduced.

The present invention is not limited to the structure of the embodiment shown above, but includes all structures which do not violate the spirit of the present invention. For example, the operation of the first float 13 and the second float 21 is not limited to the above-described embodiment, and for example, when the liquid level of the fuel tank 24 becomes high, the first float 13 and the second float 21 The float 21 rises, and the first valve body 14 and the third valve portion 14B move the first valve seat 19A and the third valve seat 20C.
At the same time as or before closing the second
The second valve body 21A of the float 21 also includes one that closes the second valve seat 20D. Further, the tubular body 20 is not limited to the structure that hangs from the upper wall of the case 12 as in the illustrated embodiment, but may be fixed by a holding frame extending from the side wall of the case 12.

[0033]

EFFECTS OF THE INVENTION According to the present invention, which is constructed and operates as described above, the following effects can be obtained. Since the breathing passage is easily opened by the second valve body,
The sticking of the first valve body due to the internal pressure of the fuel tank is eliminated. Since the breathing passage is not suddenly closed by the stop valve, the pressure in the fuel tank suddenly rises and fuel gas does not blow out from the filler pipe during refueling. Since the second valve body is moved up and down by the second float, the sealability of the second valve opening due to the second valve body does not deteriorate.

Further, there is no possibility that fuel splashes will directly reach the canister side from the valve opening through the breathing passage at the time of refueling or the like, and the breathing system can be designed to have a short length. The layout is simple.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a stop valve showing an embodiment of the present invention.

FIG. 2 is a front view taken along the line AA of FIG.

FIG. 3 is a sectional view taken along line BB in FIG.

FIG. 4 is a cross-sectional view illustrating the operation of the stop valve of the present invention, showing a state in which the first valve body closes the first valve opening.

FIG. 5 is a cross-sectional view illustrating the operation of the stop valve of the present invention, showing a state in which the second valve body closes the second valve port.

FIG. 6 is a cross-sectional view showing a conventionally known stop valve.

FIG. 7 is an exploded perspective view of the float portion of the stop valve shown in FIG.

[Explanation of symbols]

 11 Stop Valve 12 Case 12A Guide Rib 12B Through Hole 12C Engagement Hole 13 First Float 13A Fuel Splash Outflow Prevention Wall 13B Attachment 14 First Valve 14A Through Port 14B Third Valve 15 Breathing Passage 16 Bottom Plate 16A Spring accommodation protruding wall 16B Engagement leg 17 Compartment pendant 18 Spring 19 First valve opening 19A First valve seat 20 Cylindrical body 20A Recess 20B Second valve opening 20C Third valve seat 20D Second valve seat 20E through hole 21 second float 21A second valve body 22 spring 23 fuel splash out prevention plate 24 fuel tank

Claims (5)

[Claims] 1. A case, a first float provided inside the case so as to be vertically movable and having a space therein, a first valve element provided on an upper surface of the first float, and the case. A first valve opening formed on the upper surface of the first valve opening, a first valve seat formed around the first valve opening, a breathing passage provided downstream of the first valve opening, and A second valve opening provided inside the first valve opening, a tubular body that defines and forms the second valve opening, a second valve seat provided at the open end of the tubular body, and A third valve seat, a through hole provided in the first valve body, and a through hole end of the first valve body, and the third valve is provided by vertical movement of the first valve body. A third valve portion that opens and closes the seat, a second float provided inside the first float, and an upper surface of the second float that moves up and down the through hole. A stop valve provided in the fuel tank, comprising a second valve body for opening and closing the second valve seat of the tubular body, and an opening for communicating the inside of the tubular body with the breathing passage. Then, when the liquid level of the fuel tank rises, the first float and the second float rise, and the first valve body and the third valve portion move to the first valve seat and the third valve portion. A structure of a stop valve, characterized in that a third valve seat is closed, and the second valve body of the second float closes the second valve seat. 2. A case, a first float provided inside the case so as to be vertically movable and having a space inside, a first valve element provided on an upper surface of the first float, and the case. A first valve opening formed on the upper surface of the first valve opening, a first valve seat formed around the first valve opening, a breathing passage provided downstream of the first valve opening, and A second valve opening provided inside the first valve opening, a tubular body that defines and forms the second valve opening, a second valve seat provided at the open end of the tubular body, and A third valve seat, a through hole provided in the first valve body, and a through hole end of the first valve body, and the third valve is provided by vertical movement of the first valve body. A third valve portion that opens and closes the seat, a second float provided inside the first float, and an upper surface of the second float that moves up and down the through hole. A stop valve provided in the fuel tank, comprising a second valve body for opening and closing the second valve seat of the tubular body, and an opening for communicating the inside of the tubular body with the breathing passage. At the first liquid surface position of the fuel tank, the first float rises and the first valve body and the third valve portion close the first valve seat and the third valve seat. However, the second valve element of the second float closes the second valve seat at a second liquid surface position higher than the first liquid surface position of the fuel tank. The structure of the stop valve. 3. An outer peripheral edge of an end portion of the tubular body is the third valve seat, and an inner peripheral edge of the tubular body is the second valve seat. Claim 1 or Claim 2
Structure of stop valve described. 4. The structure of the stop valve according to claim 3, wherein the end portion of the tubular body is a conical recess. 5. The structure of the stop valve according to claim 1, wherein the cylindrical body is provided so as to hang from an upper surface of the case.