JP2007261384A - Fuel shutoff valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel shutoff valve 10 capable of rapidly shutting off a connection passage, and reducing the outflow of a fuel during that time. <P>SOLUTION: The fuel shutoff valve 10 comprises a casing 20, a float mechanism 50, and a spring 70. The float mechanism 50 comprises a float 51 and a seat part 55a is provided on an upper portion of the float 51 to open/close a connection passage 32a. The center of gravity of the float 51 is formed so as to be offset from the axis of the float 51 so that the float 51 is inclined when a buoyancy is generated in the float 51, and the float elevates while being brought into contact with an inner wall of the casing 20 and takes an inclined posture. While the float 51 is in the inclined posture, the seat part 55a is brought into contact with the seal part 32b in a parallel posture to close the connection passage 32a. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel cutoff valve that is attached to an upper portion of a fuel tank and opens and closes a connection passage that connects the inside and outside of the fuel tank, and more particularly relates to a shape of a float.

  Conventionally, patent document 1 etc. are known as this kind of a fuel cutoff valve. The fuel shut-off valve is mounted on the upper tank wall of the fuel tank, and includes a casing, a lid, a float, and a spring. The casing includes an upper wall, a side wall integrally formed on the outer peripheral portion of the upper wall, and a bottom plate attached to the lower end of the side wall, and uses an inner space as a valve chamber. The valve chamber houses a float having a conical valve portion at the top thereof. The valve portion opens and closes a connection passage connected to the outside of the fuel tank. The float is supported by a spring placed on the bottom plate. In addition, the float is configured such that its center of gravity is decentered from the axial center, and the impact force on the seal portion of the valve portion is mitigated.

  However, in this conventional technique, after the valve portion hits one end of the seal portion, the valve portion slides on the seal portion while returning the inclination of the float, and finally sits over the entire surface of the seal portion, thereby connecting the connection passage. It is shut off. For this reason, there is a problem that fuel is likely to leak until the valve portion slides on the seal portion and sits on the entire surface, that is, until the float posture returns.

JP-A-5-169987

  An object of the present invention is to provide a fuel cutoff valve in which the connection passage is shut off quickly and the outflow of fuel to the outside is reduced in the meantime, based on solving the problems of the conventional technology. .

The present invention made to solve the above 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 having a valve chamber communicating with the inside of the fuel tank and the connecting passage, and a seal portion provided facing the connecting passage;
A float mechanism that has a float that is housed in the valve chamber and moves up and down according to the fuel level in the fuel tank, and a seat portion that is provided on the float and opens and closes the connection passage;
With
The float's center of gravity is formed to be eccentric from the axis of the float so that when the buoyancy is generated in the float, the float is inclined and takes an inclined posture that rises while contacting the inner wall of the casing.
In a state where the float is in the inclined posture, the seat portion is formed so as to contact in a posture parallel to the seal portion and close the connection passage.

  When the fuel in the fuel tank using the fuel cutoff valve according to the present invention flows into the valve chamber and the fuel level rises, the float rises due to buoyancy. The center of gravity of the float is different from the direction in which the float receives buoyancy, that is, receives buoyancy at a position eccentric from the center of gravity of the float. The buoyancy applied in such an eccentric direction becomes a moment for rotating the float and tilts the float. The float is tilted until the upper end and the lower end opposite to the upper end are in contact with the inner wall of the casing at two locations, that is, tilted to a tilted posture that is the maximum allowable tilt. And a float raises with an inclination posture by buoyancy. Since the seat portion of the float is set so as to be parallel to the seal portion in an inclined posture, the float portion does not tilt further from the state in contact with the seal portion. Therefore, the seat portion does not slide with respect to the seal portion, and is seated uniformly on the seal portion to close the connection passage. As described above, the seat portion does not slide with respect to the seal portion, and the connection passage is quickly sealed. Therefore, not only is the response excellent, but also minute fuel leaks until the seal is sealed. be able to.

  On the other hand, when the fuel level in the valve chamber of the casing is lowered, the float is lowered, so that the seat part is separated from the seal part, the connection passage is opened, and the fuel tank communicates with the outside. At the time of the restart valve, the float descends while rotating in the direction of correcting the inclination. At this time, the seat portion is separated from the seal portion with a small force, and thus has excellent restart valve characteristics.

As a preferred aspect of the present invention, the casing includes a bottom plate that supports the float at a lower portion of the casing, and a lower surface of the float placed on the bottom plate and an upper surface provided with the seat portion are not The structure currently formed in parallel can be taken. In addition to the configuration in which the upper surface and the lower surface of the float are set to be non-parallel, the seat portion is inclined in the float by making the upper surface and the lower surface parallel and inclining one of the seat portion or the seal portion. And the seal portion may be parallel to each other.
Further, as a preferred aspect of the present invention, it is possible to adopt a configuration in which the center of the seat portion is set on the axial center of the seal portion in the inclined posture of the float.

  Furthermore, the sheet portion is formed integrally with the upper portion of the float, and further includes a sheet member formed of a flexible material and attached to the upper portion of the float. The structure currently formed in the upper surface of a member may be taken. In this case, even if the center axis of the connection passage does not coincide with the center axis of the float, the sealing performance is not impaired.

  Furthermore, as another preferred aspect, a spring that urges the float upward can be provided, and the urging force of the spring can be configured to be eccentric from the axis of the float. In this case, the float includes a spring storage chamber that is formed in a recess upward from the lower surface of the float to store the spring, and the casing includes a bottom plate that supports the float at a lower portion of the casing. The spring is supported by an upper support upper end of the spring storage chamber and the bottom plate, and the spring storage chamber has a configuration in which a surface passing through the entire circumference of the spring support end is set non-parallel to the bottom plate. be able to. With this configuration, the spring biasing force can be adjusted with a simple configuration so as to be eccentric.

  In addition, the float may be configured to be thinned upward from the lower surface of the float so that the center of gravity of the float is eccentric from the axis. With this configuration, the center of gravity and the axis of the float can be made different with a simple configuration.

As another aspect of the present invention,
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 having a valve chamber communicating with the inside of the fuel tank and the connecting passage, and a seal portion provided facing the connecting passage;
A float mechanism that has a float that is housed in the valve chamber and moves up and down according to the fuel level in the fuel tank, and a seat portion that is provided on the float and opens and closes the connection passage;
With
The float's center of gravity is formed to be eccentric from the axis of the float so that when the buoyancy is generated in the float, the float is inclined and takes an inclined posture that rises while contacting the inner wall of the casing.
In a state where the float is in the inclined posture, the seat portion is formed so as to contact the seal portion over the entire circumference of the seat portion and close the connection passage. .
In the aspect of the present invention, when the buoyancy is generated in the float, the float is inclined and rises while contacting the inner wall of the casing. When the float rises to the highest position in a state where the float is in the inclined posture, the seat portion contacts the seal portion over the entire circumference of the seat portion and closes the connection passage. As a preferred configuration of this aspect, the seat portion protrudes upward from the upper surface of the float and has a substantially conical shape, and the seal portion is a curved surface that is in close contact with the seat portion. As described above, the sheet portion and the seal portion can have various shapes such as a conical shape in addition to a flat surface as long as both are in close contact with each other.

  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 cutoff valve 10 FIG. 1 is a cross-sectional view showing a fuel cutoff valve 10 attached to an upper portion of a fuel tank FT of an automobile according to an embodiment of the present invention. The fuel shut-off valve 10 is a so-called in-tank type that is mounted in the fuel tank FT. When the fuel in the fuel tank FT rises when the vehicle is tilted or the vehicle suddenly turns, the fuel shut-off valve 10 It is a valve that regulates the outflow. The fuel cutoff valve 10 includes a casing 20, a float mechanism 50, and a spring 70 as main components. A valve mounting portion 21 is integrally formed on the upper portion of the casing 20 and is mounted in the fuel tank FT via a bracket BK welded to the lower surface of the tank upper wall FTa of the fuel tank FT.

(2) Configuration of Each Part of Fuel Shutoff Valve 10 FIG. 2 is an exploded sectional view showing the fuel cutoff valve. In FIG. 2, the casing 20 includes a casing body 30 and a bottom plate 35 attached to the lower portion of the casing body 30. The casing body 30 includes a ceiling wall portion 32 and a side wall portion 33 extending in a cylindrical shape downward from the ceiling wall portion 32, and is a cup-shaped valve surrounded by the ceiling wall portion 32 and the side wall portion 33. A chamber 30S is formed, and a lower portion thereof is a lower opening 30a. A connection passage 32a passes through the center of the ceiling wall portion 32, and the seal chamber 32b is provided on the valve passage 30S side of the connection passage 32a. A vent hole 33a for connecting the inside of the fuel tank FT and the valve chamber 30S is formed in the upper portion of the side wall portion 33, and an engaging claw 33b is formed in the lower portion thereof. The engaging claw 33 b is for attaching the bottom plate 35. The bottom plate 35 is a member that closes the lower opening 30a of the casing body 30, and the lower opening of the casing body 30 is engaged by engaging the engaging claw 33b of the casing body 30 with the engaging hole 35a formed in the outer peripheral portion thereof. It is mounted so as to close 30a. A communication hole 35c is formed through the bottom plate 35 so as to surround the central communication hole 35b and the communication hole 35b. These communication holes 35 b and 35 c are formed so as to face the lower surface of the float mechanism 50. A spring support portion 35 d for supporting the lower end of the spring 70 is formed on the upper surface of the bottom plate 35.

  A tubular body portion 37 protruding from the center to the side is formed on the upper portion of the casing body 30. A tube passage 37a is formed in the tube body portion 37. One end of the tube passage 37a is connected to the valve chamber 30S via the connection passage 32a of the casing body 30, and the other end is connected to the canister side. ing.

  FIG. 3 is a perspective view showing the float mechanism 50. 2 and 3, the float mechanism 50 includes a float 51 and a sheet member 55 mounted on the top of the float 51. The float 51 includes an upper wall portion 51a, a columnar side wall portion 51b formed downward from the outer periphery of the upper wall portion 51a, and a bottom wall portion 51c, that is, an upper wall portion 51a that is an upper surface of the column. The bottom wall 51c, which is the lower surface, is formed so as to be non-parallel. A spring accommodating chamber 51S for accommodating the spring 70 is formed inside the float 51 from the bottom wall 51c upward. That is, the spring 70 is disposed in the spring storage chamber 51S and urges the float 51 upward by being interposed between one end of the float 51 and the spring support portion 35d of the bottom plate 35.

  The seat member 55 is supported by an umbrella-shaped valve support projection 53 that projects from the upper center of the float 51. The sheet member 55 is formed of a flexible material (rubber material, thermoplastic elastomer, etc.), that is, includes a disk-shaped sheet portion 55a and a support hole 55b penetrating through the center of the sheet portion 55a. The valve support protrusion 53 is press-fitted into the support hole 55 b and engaged with the peripheral edge of the lower surface of the valve support protrusion 53 to be attached to the upper portion of the float 51.

  FIG. 4 is an explanatory diagram for explaining a state in which the float 51 is inclined. In the float 51, since the bottom wall portion 51c and the upper wall portion 51a are formed non-parallel, the center of gravity G of the float 51 moves in the direction in which the volume of the upper wall portion 51a is large. It is in an eccentric position with respect to the axial center CA. Now, if fuel flows into the valve chamber 30S and buoyancy is generated in the float 51, it can be assumed that the buoyancy vector is on the axis CA, so that a moment acts for the eccentric distance, and the upper end of the float 51 It tilts until the lower end side opposite to the upper end contacts the inner wall of the casing 20 (inclined posture). The seat portion 55a of the float 51 in the inclined posture is formed so as to contact in a posture parallel to the seal portion 32b and close the connection passage 32a. At this time, the center of the seat portion 55a is set to be positioned on the axial center of the seal portion 32b.

(3) Operation of the fuel cutoff valve 10 Next, the operation of the fuel cutoff valve will be described. In FIG. 1, when the fuel level in the fuel tank rises due to vehicle inclination or the like, the fuel vapor accumulated in the upper part of the fuel tank enters the valve chamber 30S through the vent hole 33a and the communication holes 35b and 35c. The valve chamber 30S is released to the canister side through the connection passage 32a and the pipe passage 37a. As the fuel level in the fuel tank FT rises, the fuel flows into the valve chamber 30S through the communication holes 35b and 35c. As shown in FIG. 5, when the fuel level reaches a predetermined level, the balance between the buoyancy of the float mechanism 50 and the upward force due to the load of the spring 70 and the downward force due to the weight of the float mechanism 50 is balanced. Thus, the float mechanism 50 is raised when the former exceeds the latter. At this time, since the float 51 can be assumed to have a buoyancy vector on the axis CA, a moment acts by the eccentric distance, and the upper end of the float 51 and the lower end opposite to the upper end contact the inner wall of the casing 20. (Tilt posture). Then, when the float mechanism 50 is lifted while keeping the tilted posture as described above and the seat member 55 is seated on the seal portion 32b, the connection passage 32a is closed. As a result, when the vehicle is inclined, the fuel vapor can escape from the fuel tank FT and the fuel can be prevented from flowing out of the fuel tank FT.

  On the other hand, when the fuel level in the fuel tank FT decreases and the fuel in the valve chamber 30S is discharged from the communication holes 35b, 35c, etc., the float mechanism 50 reduces its buoyancy and receives a downward force. The sheet member 55 is lowered while returning its inclination, and thereby the sheet member 55 is separated from the seal portion 32b and opens the connection passage 32a.

(4) Operation and effect of fuel cutoff valve The configuration of the above embodiment provides the following operation and effect.
(4) -1 The float 51 takes an inclined posture by receiving buoyancy at a position eccentric from the center of gravity, and ascends in a stable posture as it is. In the inclined posture of the float 51, the seat portion 55a is parallel to the seal portion 32b and sits uniformly on the entire seal portion 32b as the float 51 rises. That is, the seat portion 55a does not slide with respect to the seal portion 32b, and is seated uniformly on the seal portion 32b to close the connection passage 32a. In this way, the seat portion 55a does not slide with respect to the seal portion 32b, and the connection passage 32a is quickly sealed. It can eliminate leaks.

(4) -2 When the fuel shut-off valve is restarted, the float 51 descends while rotating in a direction to correct the inclination. At this time, the seat portion 55a is partially separated from the seal portion 32b with a small force, and thus has excellent restart valve characteristics.

(5) Other Embodiments 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.

(5) -1; FIG. 6 is a sectional view showing a fuel cutoff valve 10B according to another embodiment. The present embodiment is characterized in that the center of gravity of the float 51B is decentered by the biasing force of the spring 70B applied to the float 51B. That is, the spring storage chamber 51BS of the float 51B includes a spring support end 51BSa whose depth is not uniform over the entire circumference. FIG. 7 is an explanatory view for explaining the shape of the spring storage chamber 51BS of the float 51B, and is a perspective view of the float 51B taking a half section in the axial direction. That is, as shown in FIGS. 6 and 7, the spring support end 51BSa differs by a height L1 around the periphery, and a surface P1 passing through the entire circumference of the spring support end 51BSa is not parallel to the surface P2 of the bottom plate 35B. It has become. Therefore, as shown in FIG. 8, the spring 70 </ b> B applies a force that inclines the float 51 </ b> B with different amounts of compression in the circumferential direction. Thereby, the raising force which makes the float 51B eccentric can be easily realized by the arrangement of the spring 70B.

(5) -2; FIG. 9 is a cross-sectional view showing a fuel cutoff valve 10C according to another embodiment. In the float 51C, a lightening 51Cd is formed at a position different from the axial center from the bottom wall portion 51Cc upward. As a result, the center of gravity and the axis of the float 51C are decentered to facilitate the inclination of the float 51C.

(5) -3; FIG. 10 is a perspective view showing a float according to another embodiment. The float 51D in the above embodiment is characterized by a structure in which the guide protrusion 52D is formed on the side wall 51Db. That is, the guide ridges 52D are provided on the side wall 51Db of the float 51D at eight equal intervals in the circumferential direction and project in a rib shape in the vertical direction, and are guided in contact with the inner wall of the casing in the inclined posture of the float 51D. Is.

(5) -4; FIG. 11 is a cross-sectional view showing a fuel cutoff valve 10E according to another embodiment. The fuel cutoff valve 10E in the present embodiment is characterized by the shape of the seat portion 55Ea of the float 51E and the shape of the seal portion 32Eb facing the connection passage 32Ea. That is, the seat portion 55Ea protrudes upward in a conical shape from the upper surface of the float 51E of the float mechanism 50E. On the other hand, the seal portion 32Eb is a curved surface that is in close contact with the seat portion 55Ea.
As shown in FIG. 12, when the buoyancy is generated in the float 51E, the float 51E is inclined and inclines so as to rise while contacting the inner wall of the casing 20E. When the float 51E rises to the highest position in a state where the float 51E is in the inclined posture, the seat portion 55Ea contacts the seal portion 32Eb over the entire circumference of the seat portion 55Ea and connects the connection passage 32Ea. close. As described above, the sheet portion and the seal portion can have various shapes such as a conical shape in addition to a flat surface as long as both are in close contact with each other.

(5) -5; In the above embodiment, the center of gravity and the axis are decentered by changing the shape of the float. However, the present invention is not limited to this, and the float can be changed if the center of gravity of the float and the direction of buoyancy can be changed. You may provide the weight of another member in the edge part.

(5) -6; The fuel shut-off valve according to the above embodiment is used in a so-called in-tank type mounted inside the fuel tank, but is not limited to this, and is welded to the upper surface of the tank upper wall of the fuel tank. In addition, the present invention can be applied to a configuration in which the lower part is inserted into the mounting hole.

(5) -7; Although the sheet portion of the above embodiment is formed of rubber separately from the float, it is not limited thereto, and may be formed of resin integrally or separately from the float.

It is sectional drawing which shows the fuel cutoff valve attached to the upper part of the fuel tank of the motor vehicle concerning one Example of this invention. It is sectional drawing which decomposes | disassembles and shows a fuel cutoff valve. It is a perspective view which shows a float mechanism. It is explanatory drawing explaining the state which has taken the inclination attitude | position of the float. It is explanatory drawing explaining operation | movement of a fuel cutoff valve. It is sectional drawing which shows the fuel cutoff valve concerning another Example. It is explanatory drawing explaining the shape of the spring storage chamber of a float. It is explanatory drawing explaining operation | movement of the fuel cutoff valve concerning another Example. It is sectional drawing which shows the fuel cutoff valve concerning another Example. It is a perspective view which shows the float concerning another Example. It is sectional drawing which shows the fuel cutoff valve concerning another Example. It is explanatory drawing explaining operation | movement of the fuel cutoff valve of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fuel cutoff valve 10B ... Fuel cutoff valve 10C ... Fuel cutoff valve 10E ... Fuel cutoff valve 20 ... Casing 20E ... Casing 21 ... Valve attachment part 30 ... Casing Main body 30a ... Lower opening 30S ... Valve chamber 32 ... Ceiling wall 32a ... Connection passage 32b ... Sealing portion 32Ea ... Connection passage 32Eb ... Sealing portion 33 ... Side wall 33a ... Vent hole 33b ... Engagement claw 35 ... Bottom plate 35B ... Bottom plate 35a ... Engagement hole 35b, 35c ... Communication hole 35d ... Spring support 37 ... Pipe Body part 37a ... Pipe passage 50 ... Float mechanism 51 ... Float 51a ... Upper wall part 51B ... Float 51b ... Side wall part 51BS ... Spring storage room 51BSa ... Spring support End 51C ... Float 51c ... Bottom wall 51Cc ... Bottom wall 51D ... Float 51Db ... Side wall 51E ... Float 51S ... Spring storage 52D ... Guide protrusion 53 ... Valve support protrusion 55 ... Seat member 55a ... Sheet part 55b ... Support hole 55Ea ... Seat part 70 ... Spring 70B ... Spring G ... center of gravity CA ... axis BK ... bracket FT ... fuel tank FTa ... tank upper wall

Claims (9)

A fuel cutoff valve that is mounted on the upper part of the fuel tank (FT) and that opens and closes a connection passage (32a) that connects the inside of the fuel tank (FT) and the outside, thereby disconnecting the fuel tank (FT) from the outside. ,
A casing (20) having a valve chamber (30S) communicating the fuel tank (FT) with the connection passage (32a), and a seal portion (32b) provided facing the connection passage (32a). When,
A float (51) that is housed in the valve chamber (30S) and moves up and down in accordance with the fuel level in the fuel tank (FT), and opens and closes the connection passage (32a) provided at the top of the float (51). A float mechanism (50) having a seat portion (55a) to perform,
With
The center of gravity of the float (51) is such that the float (51) is inclined and rises while contacting the inner wall of the casing (20) when buoyancy is generated in the float (51). Formed to be eccentric from the axis of the float (51),
In a state where the float (51) is in the inclined posture, the seat portion (55a) is formed in contact with the seal portion (32b) in a posture parallel to the connection passage (32a). A fuel shut-off valve, characterized in that The fuel cutoff valve according to claim 1,
The casing (20) includes a bottom plate (35) that supports the float (51) at a lower portion of the casing (20),
A fuel cutoff valve in which a lower surface of the float (51) placed on the bottom plate (35) and an upper surface provided with the seat portion (55a) are formed non-parallel. The fuel cutoff valve according to claim 1 or 2,
A fuel cutoff valve that is set so that the center of the seat portion (55a) is positioned on the axial center of the seal portion (32b) when the float (51) is inclined. The fuel cutoff valve according to any one of claims 1 to 3,
A sheet member (55) formed of a flexible material and attached to the upper part of the float (51) is provided on the upper part of the float (51),
The seat part (55a) is a fuel cutoff valve formed on the upper surface of the seat member (55). The fuel cutoff valve according to claim 1,
A spring (70B) for urging the float (51B) upward is provided, and the urging force of the spring (70B) is eccentric from the axis of the float (51B) so as to tilt the float (51B). Fuel cutoff valve set to. The fuel cutoff valve according to claim 5,
The float (51B) includes a spring storage chamber (51BS) that is formed in a recess upward from the lower surface of the float (51B) and stores the spring (70B).
The casing (20B) includes a bottom plate (35B) that supports the float (51B) at the bottom of the casing (20B),
The spring (70B) is supported by the spring support end (51BSa) at the top of the spring storage chamber (51BS) and the bottom plate (35),
The spring support end (51BSa) is a fuel cutoff valve in which a surface passing through the entire circumference of the spring support end (51BSa) is set non-parallel to the bottom plate (35). The fuel cutoff valve according to any one of claims 1 to 6,
The float (51C) is a fuel cutoff valve that is formed so that the center of gravity of the float (51C) is eccentric from the axial center by being thinned upward from the lower surface of the float (51C). In a fuel cutoff valve that is mounted on the upper part of the fuel tank and that opens and closes a connection passage (32Ea) that connects the inside and outside of the fuel tank to cut off the communication between the fuel tank and the outside.
A casing (20E) having a valve chamber communicating the fuel tank and the connection passage (32Ea), and a seal portion (32Eb) provided facing the connection passage (32Ea);
A float (51E) which is housed in the valve chamber and moves up and down according to the fuel level in the fuel tank; and a seat portion (55Ea) which is provided at the top of the float (51E) and opens and closes the connection passage (32Ea). A float mechanism (50E) having
With
The center of gravity of the float (51E) is such that the float (51E) is inclined and rises while contacting the inner wall of the casing (20E) when buoyancy is generated in the float (51E). Formed to be eccentric from the axis of the float (51E),
In a state where the float (51E) is in the inclined posture, the seat portion (55Ea) contacts the seal portion (32Eb) over the entire circumference of the seat portion (55Ea) and connects the connection passage (32Ea). ) Is formed so as to be closed. The fuel cutoff valve according to claim 8,
The seat part (55Ea) protrudes upward from the upper surface of the float (51E) and has a substantially conical shape, and the seal part (32Eb) is a fuel cutoff valve that is a curved surface closely contacting the seat part (55Ea).

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