JP2008184093A - Fuel cutoff valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cutoff valve 10 for reducing leakage of fuel to an external part, even if a liquid level suddenly lowers when becoming near a submerged state under liquid, without submerging the opening vicinity of a connecting passage 31b under the liquid by an inclination of a fuel tank FT. <P>SOLUTION: This fuel cutoff valve 10 has a casing body 30 forming a valve chest 30S, and a float mechanism 50 stored in the valve chest 30S and having a valve part 52. The connecting passage 31b is opened and closed by the valve part 52 by lifting of the float mechanism 50. A ventilation passage forming projection part 37 is projected toward an opening of the connecting passage 31b in a side wall part 32 of the casing body 30, and a ventilation passage 38 is penetrated through the ventilation passage forming projection part 37. The ventilation passage 38 has a ventilation inlet 38a formed in the side wall part 32 and facing the fuel tank FT, and a ventilation outlet 38b arranged under a seal part 31c. When the ventilation outlet 38b is submerged under the liquid, an upper space USp of a sealed state surrounded by a ceiling wall part 31 and a side wall part 32 is formed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel cutoff valve that is attached to an upper part of a fuel tank and that opens and closes a connection passage that connects the inside and outside of the fuel tank to cut off communication between the fuel tank and the outside.

  A fuel shut-off valve (rollover valve) is provided at the top of the fuel tank to ensure ventilation to the outside of the fuel tank and to prevent liquid fuel from flowing out when the vehicle is tilted. ing. By the way, in recent years, flattening of fuel tanks has been studied in order to cope with various and large living spaces of vehicles. In such flattened fuel tanks, in order to reduce the proportion of dead space above the fuel tanks. In addition, it is preferable to set the fuel level to be closed as high as possible. However, when the fuel level is set high when the valve is closed, the fuel cutoff valve is liable to be submerged. As a configuration for making it difficult to submerge such liquid, as shown in Patent Document 1, there is known means for providing a cylindrical barrier wall projecting downward on the outer peripheral portion of the opening of the connection passage. However, this cylindrical barrier becomes a narrow space when the valve portion of the float enters the barrier, so that even if the fuel level drops with this space filled with fuel, it is difficult for the fuel to be discharged from the space. . For this reason, when air flows by opening the valve, the fuel in the space is easily involved and flows out to the outside.

JP-A-4-201718

  The present invention solves the above-mentioned problems of the prior art, and does not cause the vicinity of the opening of the connection passage to be submerged. Even if the liquid level suddenly falls close to the submerged state, the outside of the fuel is removed. An object of the present invention is to provide a fuel shut-off valve with reduced leakage.

The present invention made to solve the problems
In a fuel shut-off valve that is mounted on the upper part of the fuel tank, and that opens and closes a connection passage that connects the inside and outside of the fuel tank so as to cut off communication between the fuel tank and the outside.
A casing body that is surrounded by a ceiling wall portion that penetrates the connection passage and a cylindrical side wall portion and forms a valve chamber that communicates with the connection passage, and the ceiling wall portion that faces the connection passage A casing having a formed seal portion and a vent passage forming projection that projects from the inner wall of the side wall portion toward the opening of the connection passage and forms a vent passage that communicates the inside of the fuel tank and the valve chamber. When,
A float mechanism that is housed in the valve chamber and moves up and down according to the fuel level in the fuel tank; and a valve portion that is provided above the float and opens and closes the connection passage;
With
The vent path includes a vent inlet formed on the side wall portion and facing the fuel tank, and a vent outlet disposed below the seal portion,
The casing body is provided with an upper space that is surrounded by the ceiling wall portion and the side wall portion, and becomes airtight when the ventilation outlet is submerged,
It is characterized by.

  When the fuel tank using the fuel cutoff valve according to the present invention is inclined and reaches a predetermined liquid level in the fuel tank, the float mechanism is raised by buoyancy by the fuel flowing into the valve chamber. By raising the float mechanism, the valve portion is seated on the seal portion and the connection passage is closed, thereby shutting off the fuel tank from the outside and preventing the fuel from flowing out from the fuel tank.

 Further, the air passage formed in the air passage forming protrusion reduces the outflow of fuel from the connection passage when the vehicle is inclined or swings. That is, when the vehicle is tilted, fuel enters the valve chamber, but the ventilation path ensures ventilation between the fuel tank and the outside until the ventilation outlet is submerged. When the float rises, the valve portion closes the connection passage, and the vent outlet is submerged, a sealed upper space is formed in the upper portion of the casing body. Since this upper space makes it difficult for the seal portion to be submerged, it is possible to prevent the fuel from flowing out from the connection passage even if the float is slightly opened by vibration of the vehicle.

  On the other hand, when the vehicle is further inclined and the seal portion is in a state near the liquid submerged state, when the vehicle is slightly inclined from this state, the fuel level is lowered and the connection passage is opened by the lowering of the float mechanism. . Thereby, air goes from a ventilation outlet to a connection channel. At this time, since the space from the ventilation outlet toward the connection passage is an upper space having a large capacity, the flow velocity of air toward the connection passage is weakened, and it is difficult to entrain the fuel in the vicinity thereof.

Furthermore, as another preferred aspect, a plurality of the air passage forming protrusions may be arranged radially and at equal intervals from the seal portion toward the side wall portion. With this configuration, an upper space can be ensured regardless of the direction of inclination.
Moreover, as another aspect, the ventilation outlet can be configured to open downward. With this configuration, even if the fuel enters the ventilation path, the fuel flowing out from the ventilation outlet of the ventilation path does not go directly to the connection path, so that fuel leakage can be further prevented.

  In order to further clarify the configuration and operation of the present invention described above, preferred embodiments of the present invention will be described below.

(1) Schematic configuration of fuel shut-off valve 10 FIG. 1 is a plan view showing a fuel shut-off valve 10 according to one embodiment of the present invention, and FIG. 2 is a top view of a fuel tank FT of an automobile along line 2-2 in FIG. It is sectional drawing which shows the fuel cutoff valve 10 attached to. In FIG. 2, the surface of the fuel tank FT is formed of a composite resin material containing polyethylene, and a mounting hole FTb is formed in the tank upper wall FTa. A fuel shut-off valve 10 is attached to the tank upper wall FTa in a state where the lower part thereof enters the attachment hole FTb. The fuel shut-off valve 10 regulates that the fuel in the fuel tank FT flows out to the canister when the vehicle is tilted or swings.

(2) Configuration of Each Part of Fuel Shutoff Valve 10 The fuel cutoff valve 10 includes a casing 20, a float mechanism 50, and a spring 70 as main components. The casing 20 includes a casing main body 30, a bottom plate 35, and a lid body 40. A space surrounded by the casing main body 30 and the bottom plate 35 is a valve chamber 30S, and the valve chamber 30S is supported by a spring 70. The float mechanism 50 is accommodated.

  FIG. 3 is an exploded cross-sectional view of the fuel cutoff valve 10. The casing body 30 has a cup shape surrounded by a ceiling wall portion 31 and a cylindrical side wall portion 32, and a lower portion thereof is an opening 30a. A passage forming protrusion 31a is formed in the center of the ceiling wall 31 so as to project downward. A connection passage 31b connected to the valve chamber 30S is formed through the passage forming protrusion 31a. Yes. An annular seal portion 31c is provided on the valve chamber 30S side of the passage forming projection 31a. An engagement hole 32 a for attaching the bottom plate 35 is formed in the side wall portion 32. The bottom plate 35 is a member that closes the opening 30 a of the casing body 30, and the engagement claw 35 a formed on the outer peripheral portion of the bottom plate 35 engages with the engagement hole 32 a of the casing body 30, thereby opening the opening 30 a of the casing body 30. It is mounted to close. A spring support portion 35 c for supporting the communication hole 35 b and the lower end of the spring 70 is formed on the upper surface of the bottom plate 35.

  In addition, a ventilation path forming protrusion 37 projects from the inner wall of the side wall 32 of the casing body 30 toward the opening of the connection passage 31b. 4 is a cross-sectional view taken along line 4-4 of FIG. The ventilation path forming protrusion 37 is formed in a plate shape so as to radially divide the space surrounded by the ceiling wall part 31 and the side wall part 32 at an interval of 180 ° with the connection passage 31b as the center. A ventilation passage 38 is formed through the ventilation passage forming protrusion 37 so as to communicate the fuel tank FT and the valve chamber 30S. The ventilation path 38 includes a ventilation inlet 38a that is formed in the side wall 32 and faces the fuel tank FT, and a ventilation outlet 38b that is disposed on the seal portion 31c side. The fuel tank FT is connected to the outside via the connection passage 31b. Ensure ventilation.

  In FIG. 3, the lid body 40 includes a lid body 41, a tube body portion 42 that protrudes laterally from the center of the lid body 41, a flange 43 formed on the outer periphery of the lid body 41, and a support portion 44. These are integrally formed. A tube passage 42a is formed in the tube portion 42. One end of the tube passage 42a is connected to the valve chamber 30S of the casing body 30 through the connection passage 31b, and the other end is connected to the canister (not shown) side. Is done. The support portion 44 is a cylindrical body that is formed at the lower portion of the lid main body 41 and that fits and supports the upper portion of the casing main body 30. An engagement hole 44 a is formed in the support portion 44. The engaging body 44 holds the casing body 30 by engaging the engaging holes 44 a with engaging claws 32 c formed on the side wall portion 32 of the casing body 30. Further, an outer welded portion 43a that is welded to the tank upper wall FTa (see FIG. 2) of the fuel tank FT is formed at the lower end of the flange 43.

  The float mechanism 50 includes a float 51 and a valve portion 52 formed on the top of the float 51. The float 51 is configured in a container shape including an upper wall portion 51a and a cylindrical side wall 51b formed downward from the outer periphery of the upper wall portion 51a, and the buoyancy for generating buoyancy in the inner space. It is chamber 51S. A guide protrusion 51 c is formed on the outer periphery of the float 51. The guide protrusions 51c are provided on the side wall 51b of the float 51 so as to protrude in eight ribs at equal intervals in the circumferential direction and in a rib shape in the vertical direction. A spring 70 is disposed in the buoyancy chamber 51 </ b> S of the float 51. The spring 70 urges the float 51 upward by being interposed between one end of the float 51 and the upper surface of the bottom plate 35.

  FIG. 5 is a cross-sectional view showing the vicinity of the upper part of the float mechanism 50 and the casing body 30. The valve portion 52 includes a valve support portion 53 projecting from the upper center of the float 51 and a seat member 55 attached to the valve support portion 53. The valve support 53 includes a support protrusion 54 protruding from the upper part of the float 51. The support protrusion 54 includes a columnar support base 54a, a disk part 54b formed on the upper part of the support base 54a, and a cylindrical part 54c protruding upward from the outer periphery of the disk part 54b. The space surrounded by the support base portion 54a and the cylindrical portion 54c is a bending space 53S. In the disc part 54b of the valve support part 53, two or three liquid draining grooves (not shown) are formed. The liquid draining groove discharges the fuel accumulated in the bending space 53S and makes the sheet member 55 easily bent by venting air in the bending space 53S.

  The sheet member 55 is formed in a cup shape that opens downward from a flexible material (rubber material, thermoplastic elastomer, etc.), that is, the sheet member 56 and the outer periphery of the sheet member 56 downward. It is formed from a projecting supported portion 57, and the inside thereof is a mounting space 55S. The seat portion 56 includes a seat surface 56a that is attached to and detached from the seal portion 31c, and an elastic deformation portion 56b that is formed along the outer periphery of the seat surface 56a. When the seat surface 56a is pushed by the seal portion 31c, the elastic deformation portion 56b is elastically deformed so as to be recessed in the bending space 53S and is seated on the seal portion 31c. The supported portion 57 is formed by a cylindrical side wall portion 57a and a retaining portion 57b. The seat member 55 is attached to the valve support 53 by press-fitting the valve support 53 into the mounting space 55S.

(3) Operation of the fuel cutoff valve 10 Next, the operation of the fuel cutoff valve 10 will be described. In FIG. 2, the fuel vapor generated by the evaporation of fuel in the fuel tank FT enters the valve chamber 30S through the communication hole 35b and the vent passage 38, and from the valve chamber 30S through the connection passage 31b and the pipe passage 42a to the canister side. Escaped. Now, as shown in FIG. 6, when the fuel level FL in the fuel tank FT rises due to the inclination of the vehicle and exceeds the liquid level FL1 (cut-off point), the fuel flows not only through the communication hole 35b but also through the air. It flows into the valve chamber 30S through the passage 38. The float mechanism 50 ascends when the former exceeds the latter by the balance between the upward force due to the buoyancy of the float 51 and the load of the spring 70 and the downward force due to the weight of the float 51 and the seat member 55. . Accordingly, in the float mechanism 50, the seat member 55 of the valve portion 52 is seated on the seal portion 31c. The sheet member 55 is elastically deformed so as to bend toward the bending space 53S when pressed by the seal portion 31c, and the sheet surface 56a of the sheet member 55 closes the connection passage 31b. At this time, even if the fuel enters the valve chamber 30S and the seal portion 31c is submerged, the state in which the seat member 55 presses the seal portion 31c by its elastic force is maintained, so the fuel is stored in the fuel tank FT. It is possible to prevent outflow.

  Then, as shown in FIG. 2, when the vehicle is not inclined and the fuel tank FT returns to the horizontal posture from the state where the seal portion 31c is submerged, the fuel in the valve chamber 30S is discharged from the communication hole 35b or the like. Is done. As a result, the float mechanism 50 receives the downward force by reducing its buoyancy, and the sheet member 55 is separated from the seal portion 31c to open the connection passage 31b. At this time, the gas accumulated in the upper space of the fuel tank FT flows from the vent passage 38 through the valve chamber 30S to the outside through the connection passage 31b, and ensures ventilation with the outside.

(4) Operation and effect of the embodiment The configuration of the fuel cutoff valve 10 of the above embodiment provides the following effects.
(4) -1 As shown in FIG. 6, the air passage 38 formed in the air passage formation protrusion 37 reduces the outflow of fuel from the connection passage 31b when the vehicle swings. That is, when the vehicle is tilted, fuel enters the valve chamber 30S, but the ventilation path 38 ensures ventilation between the fuel tank FT and the outside until the ventilation outlet 38b is submerged. When the fuel level FL exceeds the predetermined liquid level FL1, the float 51 rises, the valve portion 52 closes the connection passage 31b, and the ventilation outlet 38b is submerged, the upper part of the casing body 30 is in a sealed state. An upper space USp is formed. Since the upper space USp extends the air passage 38 from the side wall to make it difficult for the seal portion 31c to be submerged, the fuel flows out from the connection passage 31b even if the float 51 is slightly opened by vibration of the vehicle. Can be prevented.

  On the other hand, when the vehicle is further tilted and the seal portion 31c is close to the liquid immersion state, as shown in FIG. 7A, when the vehicle tilts slightly, the fuel liquid level FL decreases. As the float mechanism 50 is lowered, the connection passage 31b is opened. Thereby, air goes to the connection channel | path 31b from the ventilation outlet 38b. At this time, the space from the ventilation outlet 38b toward the connection passage 31b is an upper space USp having a large capacity. Therefore, the flow velocity of air toward the connection passage 31b is weakened, and it is difficult to entrain fuel in the vicinity thereof. Moreover, only a part of the air passage forming projection 37 protrudes downward from the ceiling wall portion 31 and the space therebetween is an upper space USp, so that fuel is quickly discharged from the vicinity of the seal portion 31c. On the other hand, in the fuel cutoff valve shown in the prior art in FIG. 7B, the gap between the fuel liquid level FL and the lower end of the cylindrical barrier PW becomes the throttle RT, and the air flow rate is not weakened. Thus, the air entrains the fuel in the vicinity thereof, the fuel easily flows out to the outside, and the fuel easily stays in the cylindrical barrier PW.

(4) -2 The air passage forming protrusion 37 that forms the air passage 38 can be formed integrally with the casing body 30, and thus the configuration is simple.

(4) -3 As shown in FIG. 4, a plurality of the air passage forming protrusions 37 are arranged radially and equidistantly from the seal portion 31c toward the side wall portion 32, so that the vehicle is inclined in any direction. In addition, the upper space USp can be secured, and the seal portion 31c becomes difficult to be submerged.

  The present invention is not limited to the above-described embodiments, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

  FIG. 8 is a sectional view showing a fuel cutoff valve 10B according to another embodiment. This embodiment is characterized by the structure of the air passage that opens downward. In other words, the air passage forming protrusion 37B is projected from the side wall 32B of the casing body 30B. The ventilation path 38B of the ventilation path forming protrusion 37B is bent in an L shape, and the ventilation outlet 38Bb is opened downward. With this configuration, since the airflow flowing out from the ventilation outlet 38Bb of the ventilation path 38B does not go directly to the connection passage 31Bb, fuel leakage can be further prevented.

  In the above embodiment, the valve portion of the float mechanism is formed separately from the float by the seat member. However, the present invention is not limited to this and may be formed integrally with the float.

It is a top view which shows the fuel cutoff valve concerning one Example of this invention. It is sectional drawing which shows the fuel cutoff valve along the 2-2 line of FIG. 1, and was attached to the upper part of the fuel tank of a motor vehicle. It is sectional drawing which decomposed | disassembled the fuel cutoff valve. FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. It is sectional drawing which shows the vicinity of the upper part of a float mechanism and a casing main body. It is explanatory drawing explaining operation | movement of a fuel cutoff valve. It is explanatory drawing explaining the effect | action of a fuel cutoff valve. It is sectional drawing which shows the fuel cutoff valve concerning another Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fuel cutoff valve 10B ... Fuel cutoff valve 20 ... Casing 30 ... Casing main body 30B ... Casing main body 30S ... Valve chamber 30a ... Opening 31 ... Ceiling wall part 31a ... passage forming protrusion 31b ... connection passage 31c ... seal portion 31Bb ... connection passage 32 ... side wall portion 32B ... side wall portion 32a ... engagement hole 32c ... engagement Claw 35 ... Bottom plate 35a ... Engagement claw 35b ... Communication hole 35c ... Spring support part 37 ... Airflow path forming protrusion 37B ... Airflow path forming protrusion 38 ... Airflow path 38B ... Ventilation path 38a ... Venting inlet 38b ... Venting outlet 38Bb ... Venting outlet 40 ... Cover body 41 ... Cover body 42 ... Tube body part 42a ... Pipe passageway 43 ... Flange 43a ... Outer welding part 44 ... Support part 44a ... Engagement hole 50 ... Float mechanism 51 ... Float 51S ... Buoyancy chamber 51a ... Upper wall part 51b. .. Side wall 51c ... Guide protrusion 52 ... Valve 53 ... Valve support portion 53S ... Deflection space 54 ... Support protrusion 54a ... Support base portion 54b ... Disc portion 54c ... Cylindrical portion 54d ... Liquid drain groove 55 .. .Seat member 55S ... Installation space 56 ... Sheet part 56a ... Seat surface 56b ... Elastic deformation part 57 ... Supported part 57a ... Side wall part 57b ... Retaining part 70. .. Spring FT ... Fuel tank FTa ... Tank upper wall FTb ... Mounting hole USp ... Upper space

Claims (3)

A fuel cutoff valve that is mounted on the upper part of the fuel tank (FT) and that opens and closes a connection passage (31b) that connects the inside of the fuel tank (FT) and the outside to cut off the communication between the fuel tank (FT) and the outside. ,
A casing body (30) that forms a valve chamber (30S) that is surrounded by a ceiling wall portion (31) formed through the connection passage and a cylindrical side wall portion (32) and communicates with the connection passage (31b). And a seal portion (31c) formed on the ceiling wall portion (31) facing the connection passage (31b), and from the inner wall of the side wall portion (32) toward the opening of the connection passage (31b). A casing (20) having an air passage forming protrusion (37) that protrudes and forms an air passage (38) that connects the inside of the fuel tank (FT) and the valve chamber (30S),
A float (51) which is housed in the valve chamber (30S) and moves up and down according to the fuel level in the fuel tank (FT), and the connection passage (31b) provided at the upper part of the float (51). A float mechanism (50) having a valve part (52) for opening and closing;
With
The ventilation path (38) includes a ventilation inlet (38a) formed in the side wall (32) and facing the fuel tank (FT), and a ventilation outlet (38b) disposed below the sealing part (31c). Prepared,
The casing body (30) includes an upper space (USp) that is surrounded by the ceiling wall portion (31) and the side wall portion (32) and that becomes airtight when the ventilation outlet (38b) is submerged. That
A fuel shut-off valve characterized by The fuel cutoff valve according to claim 1,
A plurality of the air passage forming protrusions (37) are arranged radially and equidistantly from the seal portion (31c) toward the side wall portion (32). The fuel cutoff valve according to claim 1 or 2,
The ventilation outlet (38Bb) is a fuel cutoff valve that opens downward.

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