JP3421828B2 - Check valve structure - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a check valve structure suitable for adjusting internal pressure in a fuel tank for automobiles.

[0002]

2. Description of the Related Art Conventionally, when injecting fuel into a fuel tank of an automobile, for example, means shown in FIG. 13 has been adopted to detect and adjust the amount of fuel in the fuel tank. In FIG. 13, 50 is a check valve, 51 is a fuel tank, 52 is a canister, 53 is a filler tube, 54 is a vent tube, and 55 is a cut valve.

At the time of refueling the fuel, the fuel is fully regulated, and the check valve 50 is closed and the ventilation pipe 56 is shut off so that the evaporated fuel does not escape to the canister 52. As a result, the evaporated fuel passes through the vent tube 54 and is discharged from the filler tube 53. When the fuel is refueled beyond the lower surface of the vent tube 54, it starts to accumulate in the vent tube 54 and the filler tube 53, and when it reaches the tip of a refueling gun (not shown), the sensor at the tip of the refueling gun operates to refuel. It is supposed to stop.

After the refueling, in order to prevent the internal pressure of the fuel tank 51 from rising, the positive pressure valve of the check valve 50 opens to let the evaporated fuel escape to the canister 52. Further, depending on the atmospheric pressure, temperature or running condition, In order to prevent a decrease in the internal pressure of the fuel tank 51, the negative pressure valve of the check valve 50 is opened and air is introduced into the fuel tank 51 from the canister 52 side.

However, in the past, for example, in Japanese Utility Model Publication No. 62-21.
The check valve disclosed in Japanese Utility Model Publication No. 183 and Japanese Utility Model Laid-Open No. 62-37677 and shown in FIG. 14 is used. In the check valve 50 of FIG. 14, the connecting pipe 60
Is connected to a fuel tank 51, a connecting pipe 61 is connected to a canister 52, and a rubber umbrella valve 62 as a positive pressure valve and a rubber cylindrical valve as a negative pressure valve are provided in the check valve 50. 63 is provided, and the tubular valve 63 is urged by the spring 64 and abuts on the peripheral edge of the opening of the connecting pipe 61.

When the internal pressure of the fuel tank 51 rises due to the evaporated fuel, the umbrella valve 62 of the check valve 50 opens and the evaporated fuel flows from the fuel tank 51 side toward the canister 52 side. And fuel tank 5
When the pressure inside 1 becomes negative, the cylindrical valve 63 is resisted against the spring 64.
Is opened, and air is supplied from the canister 52 side to the fuel tank 51.
It flows in to the side and returns the inside of the fuel tank 51 to the normal pressure.

FIG. 15 shows a check valve disclosed in Japanese Utility Model Laid-Open No. 5-79148. The check valve 70 also includes a rubber tubular valve 71 and an umbrella valve 72. The tubular valve 71 is designed to open against the spring 73, and its basic configuration and operation are the same as those of the conventional example.

Next, FIG. 16 shows another conventional example of the check valve. In this conventional example, the check valve 8 is used.
0 is a spherical valve 81 made of aluminum, a spring 82, and a valve seat 83.
By arranging a pair of valves consisting of and in parallel with their operating directions reversed, one of them functions as a positive pressure valve and the other functions as a negative pressure valve.

[0009]

However, in the conventional example provided with the above-mentioned tubular valve and umbrella-shaped valve, since the valve is made of rubber, the valve itself is likely to swell or its performance is deteriorated by fuel. , Performance is unstable,
There was a problem that abnormal noise was generated during operation. Further, since the valve is made of rubber, it is expensive, and it is difficult to assemble it with an automatic machine, resulting in poor assembly performance. Further, there is a problem that each component is large and the degree of freedom of layout is reduced.

On the other hand, in the conventional example using the above-mentioned aluminum spherical valve, the cost is high because the aluminum material is used, and the positive pressure valve and the negative pressure valve are arranged in parallel. Therefore, the entire valve became very large, and there were many problems in terms of arrangement space and layout. Further, since the pair of valves must be arranged so that their operating directions are opposite to each other, the assembling work needs to be performed from the two upper and lower directions, which has a drawback of poor workability. Further, even from the aspect of operability as a valve, when the vehicle body is tilted, the weight of the spherical valve acts in a direction tilted from the normal operating axis direction, so an eccentric load is applied to the spring and There was a risk of causing defects.

Further, in each of the above-mentioned conventional valves, only one inlet from the fuel tank side is formed. On the other hand, when the vehicle body leans, the fuel tank also leans accordingly. In the system as shown, the outlet from the fuel tank 51 to the ventilation pipe 56 may be blocked by the fuel. Therefore, a means for installing two ventilation pipes 56 from the fuel tank 51 at both ends of the fuel tank 51 so as not to be influenced by the inclination of the vehicle body is also adopted. There is a problem in that two valves are installed for each trachea, or a T-type connecting pipe for connecting two ventilation pipes to one at the valve position is separately required.

An object of the present invention is to solve the above problems of the prior art and to provide a check valve structure which is inexpensive, compact, has good assembling workability, and is free from the risk of swelling due to fuel. It is what

[0013]

In order to achieve the above-mentioned object, the invention according to claim 1 has a positive pressure valve and a negative pressure valve in a space formed by a first body and a second body. In the check valve, the connecting pipe formed in the first body is connected to the fuel tank via the first pipe line, and the connecting pipe formed in the second body is formed in the second pipe line. Is connected to the canister side via the positive pressure valve and the negative pressure valve are arranged on the same axis, and the positive pressure valve is composed of a substantially tubular valve body and a first spring, A first valve, which is provided on the upper portion of the valve body and has a communication hole formed on the top thereof, can be fitted and contacted with a first valve seat formed in the first body, and the valve body is Is biased in the direction of the first valve seat by one spring, The valve is composed of a second valve and a second spring, and the second valve is urged by the second spring and can be fitted into a second valve seat formed in a lower portion of the valve body. The valve body is slidable in the axial direction along the inner wall surface of the first body, and the valve body is slidable between the inner wall surface of the first body and the outer peripheral surface of the first valve body. A first passage is formed to feed evaporated fuel from the fuel tank side to the canister side, and the second passage is formed.
The valve is slidable along the inner peripheral surface of the valve body, and the fuel tank is inserted from the canister side between the outer peripheral surface of the second valve and the inner peripheral surface of the valve body. A second passage for supplying air to the side is formed, the valve body includes a first valve body and a second valve body, and the first valve is formed in the first valve body, The second valve seat is formed on the second valve body, and the first valve body and the second valve body are formed on the second valve body.
The valve body is characterized by the structure of a check valve in which the negative pressure valve is built in at the time of assembly and mutual joints are welded, fixed and integrated.

According to a second aspect of the invention, there is provided a first body and a second body.
In a check valve in which a positive pressure valve and a negative pressure valve are arranged in a space formed by a body,
The connecting pipe formed in the body is connected to the fuel tank via the first conduit, and the connecting pipe formed in the second body is connected to the canister side via the second conduit. A valve and a negative pressure valve are arranged on the same axis, and the positive pressure valve is composed of a substantially cylindrical valve body and a first spring, is provided on the upper part of the valve body, and has a communication hole at the top. The first valve having the above-mentioned structure can be fitted and contacted with the first valve seat formed in the first body, and the valve body is biased in the first valve seat direction by the first spring. The negative pressure valve includes a second valve and a second spring, and the second valve is fitted to a second valve seat formed in a lower portion of the valve body by being biased by the second spring. The valve body along the inner wall surface of the first body. Is slidable in the axial direction, and feeds evaporated fuel from the fuel tank side to the canister side between the inner wall surface of the first body and the outer peripheral surface of the first valve body. 1 passage is formed, the second valve is slidable along the inner peripheral surface of the valve body, and the outer peripheral surface of the second valve and the inner peripheral surface of the valve body are formed. A second passage for supplying air from the canister side to the fuel tank side is formed between the two, and the fuel tank side connecting pipe formed in the first body is branched into two. A first connecting pipe and a second connecting pipe are formed, and the first connecting pipe and the second connecting pipe are respectively arranged near the left and right ends in the fuel tank via the first pipe line. Characterized by the structure of the check valve in communication with the cut valve Than it is.

According to a third aspect of the present invention, based on the first and second aspects, the base end portion of the second valve body is
When a large flow rate or a large pressure is applied from the fuel tank side, it contacts the annular portion formed on the outer periphery of the second body against the first spring, and the annular portion Is characterized by the structure of a check valve in which a plurality of notches for releasing the pressure at the time of contact are formed.

According to a fourth aspect of the present invention, based on the first to third aspects, the outer peripheral surface of the second valve or
The check valve has a structure in which a plurality of second ribs are provided on the inner peripheral surface of the valve body, and the second passage is formed between the respective second ribs.

[0017]

[0018]

[0019]

With the structure of the check valve according to the present invention, when the internal pressure of the fuel tank rises, when the pressure difference between the fuel tank side and the canister side overcomes the biasing force of the first spring,
The entire valve body moves to the canister side, the first valve separates from the first valve seat and becomes an open state, and the first passage opens. Therefore, the pressure is released from the fuel tank side to the canister side via the first passage, and the evaporated fuel is also sent to the canister.

On the other hand, when the internal pressure of the fuel tank decreases, the second valve moves to the fuel tank side when the pressure difference between the fuel tank side and the canister side overcomes the urging force of the second spring, and the second valve moves. After being separated from the second valve seat, it is opened and the second passage is opened. Therefore, air can be introduced into the fuel tank from the canister side via the second passage, and the inside of the fuel tank can be returned to normal pressure.

Further, when a large flow rate or large pressure is applied from the fuel tank side, the entire valve body moves downward against the first spring, and the contact portion of the valve body is formed on the outer periphery of the second body. It comes into contact with the formed annular portion. However, since the annular portion is formed with a plurality of cutout portions for releasing the pressure at the time of contact, the large flow rate or the large pressure passes through the cutout portions from the first passage and is passed through the cutout portion. It is possible to reliably prevent the check valve from being locked due to the leak.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. 1 to 10 show an embodiment of the present invention, in which 1 is a check valve according to the present embodiment.

The check valve 1 according to this embodiment is shown in FIG.
It is arranged in the system as shown in FIG. 2 and is arranged in the middle of the conduit connecting the fuel tank 2 and the canister 3. That is, cut valves 4 and 4 are provided in the fuel tank 2 near the left and right ends, respectively, and the pair of cut valves 4 are connected to the check valve 1 via a pair of first pipe lines 5. On the other hand, the check valve 1 and the canister 3 are connected by the second conduit 6.

As shown in FIG. 1, the check valve 1 is
A positive pressure valve 9 and a negative pressure valve 10 are arranged in a space formed by a first body 7 and a second body 8 each having a cylindrical main body.

In the present embodiment, the connecting pipe on the fuel tank 2 side integrally formed from the cylindrical main body 7a of the first body 7 is bifurcated to form the first connecting pipe 11 and the first connecting pipe 11. Two
A connecting pipe 12 is formed, and the first connecting pipe 11 and the second connecting pipe 12 are connected to a pair of cut valves 4 and 4 arranged in the fuel tank 2 via a first pipe line 5, respectively. ing. Further, the first connecting pipe 11 and the second connecting pipe 12 are converged into one at the base end portion and are integrally connected to the first body body 7a, and the first valve is provided around the opening of this connecting portion. A seat 13 is formed.

On the other hand, the connecting pipe 14 on the canister 3 side, which is integrally formed by extending from the main body 8a of the second body 8,
It communicates with the canister 3 via the second conduit 6.

In the present embodiment, as shown in FIG. 1, the first component is that the components of the positive pressure valve 9 and the components of the negative pressure valve 10 are all arranged on the same axis. Is. The positive pressure valve 9 includes a valve body 15 and a first spring 16 as a compression spring. Further, in the present embodiment, the valve body 15 has two parts, a first valve body 17 and a second valve body 18. It consists of

In the first valve body 17, a main body 17a is formed in a substantially cylindrical shape, and the first valve 20 is formed in a dome shape so as to project from an upper portion of the main body 17a. A communication hole 19 is formed at the top. The first valve body 17 is biased by the first spring 16 so that the first valve 20 can be fitted and contacted with the first valve seat 13 formed in the first body 7.

The main body portion 18a of the second valve body 18 is also formed in a substantially cylindrical shape, a second valve seat 21 having an opening in the center is formed at the base end portion of the main body portion 18a, and the outer peripheral portion of the second body is formed. Abutting portion 2 that abuts the annular portion 29 of the main body 8a of
2 is formed. As shown in FIG. 2, one end of the first spring 16 is pressed against the base end portion of the main body portion 18a, and the other end thereof is the second end.
By being pressed against the main body 8a of the body 8, a predetermined biasing force in the upward direction in FIG. 1 acts on the valve body 15.

The first valve body 17 and the second valve body 18 are connected to the negative pressure valve 1 at the time of assembly as described later.
0 is built in, and the mutual joint portions 17b and 18b are welded, fixed, and integrated to form the valve body 15.

The negative pressure valve 10 has a second valve as shown in FIG.
It is composed of a valve 23 and a second spring 24 as a compression spring. The second valve 23 is formed in a substantially semi-spherical shape with an open top and a hollow interior. Also, the second spring 24 has one end having the first valve body 1 as shown in FIG.
The second valve 23 is formed on the second valve body 18 by being pressed against the inner surface of the second valve 7, and the other end of the second valve 23 against the opening peripheral edge of the second valve 23. It can be fitted into the second valve seat 21.

On the inner wall surface of the main body 7a of the first body 7, as shown in FIG. 3, a plurality of first ribs 25 are formed radially with respect to the circumferential surface, and the first valve body main body portion 17 is formed.
The outer peripheral surface of a comes into contact with each of the first ribs 25 and is slidable in the axial direction by the pressure difference between the biasing force of the first spring 16 and the pressure from the fuel tank 2 side described later. There is. Further, between the inner wall surface of the main body 7a of the first body 7 and the outer peripheral surface of the first valve body main body portion 17a, between the first ribs 25, the evaporated fuel from the fuel tank 2 side to the canister 3 side is formed. A first passage 26 for delivering

On the other hand, on the upper outer peripheral surface of the second valve 23,
As shown in FIG. 3, a plurality of second ribs 27 are formed so as to project radially, and each of the second ribs 27 is in contact with the inner peripheral surface of the second valve body 18, and a fuel tank to be described later. The second valve 23 can slide up and down along the inner peripheral surface of the second valve body 18 by the differential pressure between the negative pressure on the second side and the biasing force of the second spring 24. In addition, the plurality of second ribs 27 of the second valve 23 and the second valve body 18
A second passage 28 that supplies air from the canister 3 side to the fuel tank 2 side is defined between the inner peripheral surface and the inner peripheral surface of the.

Instead of forming the second ribs 27 on the outer peripheral surface of the second valve 23 as in this embodiment, a plurality of second ribs 27 are formed on the inner peripheral surface side of the second valve body 18. The second passage 28 may be formed between each of the second ribs 27 and the outer peripheral surface of the second valve 23.
Also in this case, the second passage 28 is defined in the same manner.

In this embodiment, however, the first body 7, the second body 8, the first valve body 17, the second valve body 18 and the second valve 23 are all made of synthetic resin material. This is the second feature. In terms of material, the polyacetal material is most suitable in that it can surely prevent the swelling of the fuel, but it is also possible to use a synthetic resin material of other appropriate material. In addition, the first spring 16 and the second
The springs 24 are all made of stainless steel in this embodiment.

Further, the contact portion 22 of the second valve body 18
When a large flow rate or large pressure is applied from the fuel tank 2 side, the circle moves downward against the first spring 16 as shown in FIG. 6 and is formed on the outer circumference of the second body 8. Ring part 2
It is designed to abut 9. Then, the annular portion 29
The third feature of the present embodiment is that a plurality of notches 31 for releasing the pressure at the time of contact are formed in the.

That is, the annular portion 2 of the second body 8 shown in FIG.
9, the contact portions 3 of the contact portion 22 of the second valve body 18, as shown in FIG.
No. 0 is provided, and the inner wall surface of the other portion in the circumferential direction is notched as shown in FIG. 9 to form a notch 31, so that the contact portion 22 of the second valve body 18 is provided.
The pressure can be leaked from the cutout portion 31 even when the contact portion is in contact with the contact portion 30 of the second body 8.

When assembling the check valve 1 of the present embodiment having the above-mentioned structure, first, in FIGS. 1 and 2, first, the negative pressure valve 10 is provided between the first valve body 17 and the second valve body 18. The constituent second spring 24 and the second valve 23 are fitted and inserted, and the first valve body 17 and the second valve body 18 are joined to each other at the joint portions 17b and 18b.
Weld and fix. Then, the entire valve body 15 including the negative pressure valve 10 is fitted into the main body 7a of the first body 7, and then the first spring 16 is interposed between the second valve body 18 and the second body 8. After that, the first body 7 and the second body 8 are fitted to each other, and the joint portions 7b and 8b are welded and fixed to each other to complete the process. Therefore, after assembling, the negative pressure valve 10 is incorporated in the positive pressure valve 9 to operate.

As described above, since the assembling work can be performed only from one direction (downward direction in the drawing), the assembling workability is extremely good. Moreover, since the component part is made of the synthetic resin material and the spring, it is automatic. It can be assembled by machine.

Next, an operation mode of the check valve 1 according to this embodiment will be described with reference to FIGS. 2 to 6. First, FIG. 2 shows a non-operating state of the check valve 1. In this state, the first valve 20 of the positive pressure valve 9 is
Is the first of the first body 7 due to the urging force of the first spring 16.
It is fitted on the valve seat 13. In addition, the second of the negative pressure valve 10
The valve 23 is fitted to the second valve seat 21 of the valve body 15 by the urging force of the second spring 24. Therefore, the first passage 26 and the second passage 28 of the check valve 1 are both closed.

Next, FIG. 4 shows a state when the internal pressure of the fuel tank 2 rises. In this state, the differential pressure between the first connecting pipe 11 and the second connecting pipe 12 side and the connecting pipe 14 side ( When the first and second connecting pipes 11 and 12 are large), the valve body 15 as a whole moves toward the connecting pipe 14 (downward in the figure) as shown in the drawing, when the urging force of the first spring 16 is overcome. When the 1st valve 20 is separated from the first valve seat 13 and is opened,
The passage 26 opens. Therefore, from the fuel tank 2 side, as shown by the arrow in FIG. 4, the first connecting pipe 11 and the second connecting pipe 1
2, the canister 3 through the first passage 26 and the connecting pipe 14.
The pressure is released to the side, and the evaporated fuel is also sent to the canister 3.

FIG. 5 shows a state when the internal pressure of the fuel tank 2 is reduced. In this state, the first connecting pipe 11 and the second connecting pipe 11 are connected.
When the differential pressure between the connecting pipe 12 side and the connecting pipe 14 side (the connecting pipe 14 side is large) overcomes the urging force of the second spring 24, the second valve 23 moves toward the first valve 20 (in the figure) as shown in the drawing. (Upward), the second valve 23 separates from the second valve seat 21 and becomes an open state, and the second passage 28 opens. Therefore, as shown by the arrow in FIG. 5, the connecting pipe 14, the second passage 28, the communication hole 19 and the first connecting pipe 1 are provided from the canister 3 side.
Air is introduced into the fuel tank 2 through the first and second connecting pipes 12 to return the inside of the fuel tank 2 to the normal pressure.

Next, FIG. 6 shows a state in which a large flow rate or a large pressure is applied from the fuel tank 2 side. In this case, the valve body 15 as a whole moves downward against the first spring 16 as shown in FIG.
The contact portion 22 of is in contact with the annular portion 29 formed on the outer periphery of the second body 8. Therefore, conventionally, there is a problem that the check valve is locked in this state, but in the present embodiment, as described above, the annular portion 29 is provided with a plurality of notches 31 for releasing the pressure at the time of contact. Since it is formed, the large flow rate or large pressure is leaked from the first passage 26 through the notch 31 toward the connecting pipe 14,
It is possible to reliably prevent the check valve 1 from becoming locked. As shown in FIG. 10, the stopper portion 32 is provided at the lower end of the first valve body 17 to prevent the valve body 15 from moving beyond the position shown in FIG. Are formed.

In the present embodiment having the above-mentioned structure, all the components other than the spring are made of synthetic resin and have a sealing structure of synthetic resin materials, so that the cost is remarkably low. Further, as described above, the assembling work can be performed only from one direction, so that the assembling workability is extremely good. Further, since the constituent parts are made of the synthetic resin material and the spring, the assembling work can be carried out by an automatic machine. . Further, as described above, since the constituent parts are all arranged on the same axis, the assembling workability is further improved.

Further, the positive pressure valve 9 and the negative pressure valve 10
Since the valve opening pressure is adjusted by springs, it is easy to fine-tune the valve opening pressure.
Further, since the negative pressure valve 10 is incorporated in the positive pressure valve 9, the entire valve becomes compact,
The layout of parts becomes very easy.

Furthermore, a polyacetal resin material is used as the synthetic resin material, and the first spring 16 and the second spring 16 made of stainless steel are used.
When combined with the spring 24, the swelling action of the fuel can be minimized and the performance deterioration can be effectively prevented.

Further, from the aspect of operability as a valve,
Even if the vehicle body is tilted, there is no spherical valve as in the above-mentioned conventional example, so there is no risk of malfunction. Also,
The connecting pipe on the fuel tank 2 side is bifurcated to form a first connecting pipe 11 and a second connecting pipe 12, and the first connecting pipe 11 and the second connecting pipe 12 are respectively the first connecting pipe 11 and the second connecting pipe 12. Pipeline 5
Since it is connected to the cut valve 4 in the fuel tank 2 via a check valve, a check valve can be installed in each pipeline as in the above-mentioned conventional example, or one check valve can be provided in the pipeline. It is possible to solve the problem that a separate T-type connecting tube is needed separately.

Further, even when a large flow rate or large pressure is applied from the fuel tank 2 side, the annular portion 29 is formed with a plurality of notches 31 for escaping the pressure at the time of contact, The large flow rate or the large pressure is supplied from the first passage 26,
It is possible to reliably prevent the check valve 1 from being locked by passing through the notch 31 and leaking toward the connecting pipe 14.

In the above embodiment, the check valve 1 according to the present invention is arranged in the system shown in FIG. 7 as in the conventional example. However, the present invention is not limited to this. Needless to say, the present invention can be applied to any appropriate system or mechanism.

Further, the first valve 20 of the valve body 15
And the shape of the second valve seat 21 and the corresponding second valve 2
The shape of No. 3 is not limited to the above-described first embodiment, and may be, for example, a shape almost opposite to that of the first embodiment as shown in FIG. 11 or a shape as shown in FIG. Further, in the first embodiment, the first valve body 1
7 and second joints 17b and 18b of the second valve body 18
However, the case where the welding is performed on the side of the contact portion 22 of the second valve body 18 is illustrated, but the present invention is not limited to this, and the configuration may be such that the welding is performed on the side of the upper end of the second valve body 18. .

Further, various modifications can be made within the scope not departing from the gist of the present invention, such as the shapes of other components, the formation pitch, the number of formations, etc., can be appropriately changed as necessary. .

[0051]

The present invention is configured as described above, and has the following effects. (1) Since the assembling work can be performed only from one direction, the assembling workability is extremely good, and the assembling by the automatic machine becomes possible. (2) Since all the constituent parts are arranged on the same axis, the assembling workability is further improved. (3) Since the opening pressures of the positive pressure valve and the negative pressure valve are both adjusted by springs, fine tuning of the valve opening pressure is easy. (4) Since the negative pressure valve is incorporated in the positive pressure valve, the entire valve becomes compact and the layout of parts becomes very easy. (5) Even if the vehicle body is tilted, there is no spherical valve as in the above-mentioned conventional example, so there is no risk of malfunction, and the connecting pipe on the fuel tank side is branched into a fork-like shape.
Since the connecting pipe and the second connecting pipe are formed, a check valve is installed in each pipe line as in the above-mentioned conventional example, or a T-type connecting pipe that is integrated with the pipe line on the way. It is possible to solve the problem that is required separately. (6) Even when a large flow rate or a large pressure is applied from the fuel tank side, the large flow rate or the large pressure is generated from the first passage because the plurality of cutouts are formed in the annular portion. It is possible to reliably prevent the check valve from being locked by being leaked to the canister side after passing through.

[Brief description of drawings]

FIG. 1 is an exploded explanatory view showing a first embodiment of a check valve according to the present invention.

FIG. 2 is an explanatory diagram showing a non-operating state of the check valve of the first embodiment.

3 is a cross-sectional view taken along line XX of FIG.

FIG. 4 is an explanatory diagram showing an operating state of the check valve of the first embodiment.

FIG. 5 is an explanatory diagram showing an operating state of the check valve of the first embodiment.

FIG. 6 is an explanatory diagram showing an operating state of the check valve of the first embodiment.

FIG. 7 is a conceptual diagram showing a vapor recovery system according to the first embodiment.

FIG. 8 is a plan view showing a configuration of a second body of the check valve of the first embodiment.

9 is a cross-sectional view taken along the line AA of FIG.

10 is a sectional view taken along line BB of FIG.

FIG. 11 is an explanatory view of a main part showing another embodiment of the present invention.

FIG. 12 is an explanatory view of a main part showing another embodiment of the present invention.

FIG. 13 is a conceptual diagram showing a conventional vapor recovery system.

FIG. 14 is a cross-sectional view showing a conventional example of a check valve.

FIG. 15 is a sectional view showing a conventional example of a check valve.

FIG. 16 is a sectional view showing a conventional example of a check valve.

[Explanation of symbols]

1 check valve 2 fuel tank 3 canister 4 cut valve 5 first pipeline 6 second pipeline 7 First body 7a First body body 7b junction 8 second body 8a Second body body 8b junction 9 Positive pressure valve 10 Negative pressure valve 11 First connection pipe 12 Second connection pipe 13 First valve seat 14 Connection pipe 15 valve body 16 First spring 17 1st valve body 17a main body 17b joint 18 Second valve body 18a main body 18b joint 19 communication holes 20 First valve 21 Second valve seat 22 Contact part 23 Second valve 24 Second spring 25 First rib 26 First Passage 27 Second rib 28 Second passage 29 Torus 30 contact part 31 Notch 32 Stopper

─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hiroki Isobe 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Nissan Motor Co., Ltd. (56) Bibliographic references Sho 53-132029 (JP, U) 86203 (JP, U) Actual flat 6-53869 (JP, U) Actual flat 6-40539 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) F16K 17/18 B60K 15 / 077

Claims (4)

(57) [Claims] 1. A check valve in which a positive pressure valve and a negative pressure valve are arranged in a space formed by a first body and a second body, wherein a connecting pipe formed in the first body is provided. The fuel tank is connected via a first conduit, the connecting pipe formed on the second body is connected to the canister side via a second conduit, and the positive pressure valve and the negative pressure valve are the same. The positive pressure valve, which is disposed on the axial center, includes a substantially cylindrical valve body and a first spring. The positive valve is provided on the upper portion of the valve body and has a communication hole formed at the top. A first valve seat formed in the first body, and the valve body is biased toward the first valve seat by the first spring; A second valve and a second spring, wherein the second valve is The valve body is urged by a second spring and can be fitted into a second valve seat formed in a lower portion of the valve body, and the valve body slides in an axial direction along an inner wall surface of the first body. A first passage is formed between the inner wall surface of the first body and the outer peripheral surface of the first valve body for feeding evaporated fuel from the fuel tank side to the canister side. The second valve is slidable along the inner peripheral surface of the valve body, and the canister is provided between the outer peripheral surface of the second valve and the inner peripheral surface of the valve body. A second passage for supplying air from the side toward the fuel tank is formed, the valve body includes a first valve body and a second valve body, and the first valve is the first valve. The second valve seat is formed on the body, The first valve body and the second valve body are formed in a tubular body, and the negative pressure valve is built into the first valve body and the second valve body at the time of assembly, and their joints are welded, fixed and integrated. Check valve structure. 2. A check valve in which a positive pressure valve and a negative pressure valve are arranged in a space formed by a first body and a second body, wherein a connecting pipe formed in the first body is provided. The fuel tank is connected via a first conduit, the connecting pipe formed on the second body is connected to the canister side via a second conduit, and the positive pressure valve and the negative pressure valve are the same. The positive pressure valve, which is disposed on the axial center, includes a substantially cylindrical valve body and a first spring. The positive valve is provided on the upper portion of the valve body and has a communication hole formed at the top. A first valve seat formed in the first body, and the valve body is biased toward the first valve seat by the first spring; A second valve and a second spring, wherein the second valve is The valve body is urged by a second spring and can be fitted into a second valve seat formed in a lower portion of the valve body, and the valve body slides in an axial direction along an inner wall surface of the first body. A first passage is formed between the inner wall surface of the first body and the outer peripheral surface of the first valve body for feeding evaporated fuel from the fuel tank side to the canister side. The second valve is slidable along the inner peripheral surface of the valve body, and the canister is provided between the outer peripheral surface of the second valve and the inner peripheral surface of the valve body. From the side to the fuel tank side, a second passage is formed, and the connection pipe on the fuel tank side formed on the first body is bifurcated to form a first connection pipe. A second connecting pipe is formed, and the first connecting pipe and the second connecting pipe are formed. Structure of the check valve, characterized in that it is contacted to each arranged cut valve through the respective said first conduit to the right and left ends vicinity in the fuel tank. 3. A base end portion of the second valve body is a circle formed on the outer periphery of the second body against the first spring when a large flow rate or a large pressure is applied from the fuel tank side. 3. The ring portion is adapted to abut, and the annular portion is formed with a plurality of notches for releasing the pressure at the time of the abutment. Check valve structure described in. 4. A plurality of second ribs are provided on an outer peripheral surface of the second valve or an inner peripheral surface of the valve body, and the second passage is formed between the respective second ribs. The check valve structure according to any one of claims 1 to 3, wherein: