JP4888370B2 - Fuel shut-off valve - Google Patents

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.

  Conventionally, as this type of fuel cutoff valve, the technique of FIG. 1 described in Patent Document 1 is known. A conventional fuel cutoff valve is mounted on the tank upper wall of the fuel tank FT, and includes a casing that forms a valve chamber and a connection passage that connects the valve chamber and the outside, a float that is housed in the valve chamber, A spring that biases the float upward, and the float moves up and down according to the fuel level in the valve chamber to open and close the connection passage, thereby ensuring ventilation between the inside and outside of the fuel tank and the outside of the fuel To prevent spillage.

The casing in the conventional fuel shut-off valve is composed of a cylindrical casing body having a seal portion facing the connection passage, a lid attached to the upper portion of the casing body, and a bottom plate attached to the lower portion of the casing body. In addition, high-density polyethylene welded to the fuel tank is used for the lid, and polyacetal whose fuel swelling is smaller than that of the high-density polyethylene is used for the casing body. Since these resin materials do not adhere to each other, the casing body is attached to the lid through mechanical engagement means such as claws, and a seal member such as an O-ring is interposed between the two members.
However, the conventional casing has four parts including an O-ring, and it has been studied to reduce the number of parts and simplify the configuration.

As a means for solving such a problem, the technique shown in FIG. 5 of Patent Document 1 is known. The casing of the fuel cutoff valve has a configuration in which a cylindrical casing body is integrally formed from the lower part of the lid, and a bottom plate is attached to the lower part of the casing body.
However, since the lid is formed of a resin material containing high-density polyethylene that can be welded to the fuel tank, the amount of fuel swelling is larger than that of polyacetal or the like. For this reason, the fuel vapor filled in the fuel tank causes large fuel swelling around the seal portion. Such swelling of the fuel causes a deformation in which the lid is raised and unevenly curved, particularly when the lid is welded to the fuel tank and restrained. For this reason, there has been a problem that the seal portion cannot maintain high sealing performance due to the displacement or deformation of the central axis accompanying the swelling of the fuel.

JP 2001-342922 A

  An object of the present invention is to provide a fuel shut-off valve that can reduce the number of parts and maintain high sealing performance, in view of solving the problems of the conventional technology.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

[Application Example 1]
Application Example 1 includes a casing having a valve chamber connected to the fuel tank, a valve chamber connected to the fuel tank, a connection passage connecting the valve chamber and the outside, and fuel contained in the valve chamber. In a fuel cutoff valve having a float that opens and closes the connection passage by moving up and down depending on the liquid level,
The casing includes a casing main body having a cylindrical side wall, and a lid disposed on the upper side of the side wall.
The lid body covers a part of the upper opening of the side wall portion and has the connection passage, and a weld portion that is formed on the outer periphery of the lid body and can be thermally welded to the upper portion of the fuel tank, A seal portion disposed facing the connection passage and on which an upper portion of the float is seated,
The lid body has a flat plate portion that covers an outer peripheral portion of the upper opening of the casing main body, and a raised portion that arranges the seal portion above the flat plate portion,
It is characterized by.

  The casing described in Application Example 1 includes a valve chamber communicating with the fuel tank, and the float stored in the valve chamber moves up and down according to the fuel level of the fuel tank. Thus, the float prevents the fuel from flowing out of the fuel tank by opening and closing the connection passage. The fuel shut-off valve is formed of a resin material whose lid can be thermally welded to the upper part of the fuel tank, and is attached to the upper part of the fuel tank by being thermally welded. Thereby, the fuel shut-off valve can be easily attached without requiring a fastening member or the like on the upper part of the fuel tank.

  Further, the seal portion is formed integrally with the raised portion of the lid, and the connection passage is closed when the float valve portion is seated, and the inside of the fuel tank is sealed to the outside. Therefore, compared with the conventional technique in which a sealing part is provided on the casing body and the casing body is assembled with the sealing member interposed between the casing body, this application example does not require a sealing member and reduces the number of parts. Can do.

  Furthermore, since the sealing part is formed in the raised part higher than the flat plate part of the lid body, the sealing performance does not deteriorate due to fuel swelling. That is, fuel swelling occurs in the lid body due to the fuel vapor filled in the fuel tank FT. At this time, since the lid body is welded and restrained to the fuel tank, the flat plate portion of the lid body is curved so as to rise upward, and may cause uneven deformation in the circumferential direction. The raised portion is separated from the welded portion constrained by the fuel tank, is not easily affected by such uneven deformation of the flat plate portion, and uniformly swells, so that the seal portion does not undergo a large shape change. . Therefore, the seal portion is less affected by the shift of the central axis and the change in shape due to the swelling of the fuel, and can maintain high sealing performance.

[Application Example 2]
In Application Example 2, the raised portion includes a cylindrical standing wall portion protruding upward from the flat plate portion, and a top plate portion that is integrally formed on the standing wall portion and provided with the seal portion. Can take. The raised portion only needs to have a configuration in which the seal portion can be disposed above the flat plate portion, and may be an inclined wall or a dome shape in addition to the application example described above.

  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 Shutoff Valve 10 FIG. 1 is a side view showing the fuel cutoff valve 10, and FIG. 2 is a sectional view showing the fuel cutoff valve 10. The surface of the fuel tank FT is made of a composite resin material containing high-density 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 cutoff valve 10 includes a casing 20, a float 50, and a spring 70 as main components. When the fuel in the fuel tank FT rises to a predetermined liquid level, the fuel cutoff valve 10 flows out to the outside (canister). Is to regulate. Hereinafter, the configuration and operation of each part of the fuel cutoff valve 10 will be described.

(2) Configuration of each part of fuel cutoff valve 10 (2) -1 casing 20
FIG. 3 is an exploded cross-sectional view of the fuel cutoff valve 10. The casing 20 includes a casing body 30 and a lid body 40. A space surrounded by the casing body 30 and the lid body 40 is a valve chamber 20S, and a float supported by a spring 70 in the valve chamber 20S. 50 is stored.

  The casing body 30 is made of polyacetal and includes a cylindrical side wall portion 32 and a bottom wall portion 34 formed integrally with a lower portion of the side wall portion 32, and is surrounded by the side wall portion 32 and the bottom wall portion 34. A cup-shaped valve chamber 20S is formed. A communication hole 32a is formed in the side wall portion 32, and a communication hole 34a is formed in the bottom wall portion 34 to communicate the fuel tank FT and the valve chamber 20S. A spring receiving portion 34 b that supports the lower end of the spring 70 is formed at the center upper portion of the bottom wall portion 34.

The lid 40 is made of high-density polyethylene having a larger fuel swelling amount than polyacetal, and covers a lid body 41 that covers the upper opening of the side wall portion 32, and a weld portion that is formed on the outer periphery of the lid body 41 and is welded to the fuel tank FT. A flange 42 having 42a, a tube part 43 having a tube passage 43a projecting in the horizontal direction from the upper part of the lid body 41, and a passage forming part 44 are provided. The lid body 41 includes a flat plate portion 41a that covers the outer peripheral portion of the upper opening of the side wall portion 32, and a raised portion 41b that protrudes upward from the flat plate portion 41a. The raised portion 41 b includes a cylindrical standing wall portion 41 c and a top plate portion 41 d formed on the upper portion of the standing wall portion 41 c and parallel to the lid body 41.
A cylindrical passage forming portion 44 is formed at the center of the top plate portion 41d of the lid body 41 so as to face downward. A connecting passage 44a passes through the passage forming portion 44, and an annular seal portion 44b is formed on the valve chamber 20S side of the connecting passage 44a.

(2) -2 Mounting means A mounting means is provided as a configuration for mounting the casing body 30 to the lid body 40. The mounting means includes a holding portion 36 provided in the casing body 30, a cylindrical insertion portion 45 provided in the lid body 40, and a coupling means for mechanically coupling the casing body 30 and the lid body 40 with claws. It has.
FIG. 4 is an exploded side view of the fuel cutoff valve. The holding portion 36 includes a plurality of (four in the embodiment) support leg portions 36a and an annular connection portion 36b that connects the upper portions of the support leg portions 36a. The support leg 36 a is projected from the outer wall of the side wall 32 in an L-shaped cross section. FIG. 5 is a cross-sectional view taken along line 5-5 of FIG. The annular coupling part 36 b forms a holding gap 38 </ b> S in which the insertion part 45 can be inserted between the annular part 36 b and the side wall part 32 by separating a predetermined gap from the outer peripheral wall of the side wall part 32 of the casing body 30.
In addition, a plurality of ribs 38 are formed on the inner peripheral portion of the annular coupling portion 36b in the vertical direction. The rib 38 is formed in the vertical direction so as to contact the insertion portion 45 across the holding gap 38S.

  3 and 4, the connecting means includes an engaging portion 36 c provided in the holding portion 36 and an engaging hole 45 a formed in the insertion portion 45. The engaging portion 36c is a cantilever member that is formed below the annular connecting portion 36b and has a slit 36e between the engaging leg 36a and is formed so that it can be bent with the upper portion as a fulcrum. An engaging claw 36d is formed at the tip of the engaging portion 36c. On the other hand, an engagement hole 45a is formed in the insertion portion 45, and the casing body 30 is supported by the lid body 40 when the engagement claw 36d engages with the engagement hole 45a. Further, the insertion portion 45 is formed with a notch 45b upward from the bottom. The notch 45b is disposed so as to coincide with the communication hole 32a, and communicates with the valve chamber 20S through the communication hole 32a.

(2) -3 Float 50
In FIG. 3, the float 50 includes a cylindrical float main body 51 and a valve portion 52 protruding from the upper portion of the float main body 51. The float main body 51 is configured in a container shape having an open bottom, and the inner space is a float chamber 50S for generating buoyancy.

(3) Installation Work to Fuel Tank FT Next, an operation for mounting the fuel cutoff valve 10 on the tank upper wall FTa of the fuel tank FT will be described. As shown in FIG. 2, the float 50 and the spring 70 are accommodated in the valve chamber 20 </ b> S of the casing body 30. Further, as shown in FIGS. 3 and 5, the insertion portion 45 of the lid body 40 is inserted into the holding gap 38 </ b> S of the holding portion 36 of the casing body 30. At this time, the engagement claw 36d is engaged with the engagement hole 45a of the insertion portion 45 of the lid 40. Thereby, the insertion part 45 is clamped by the holding part 36, and the engaging claw 36d is engaged with the engaging hole 45a, whereby the lid body 40 and the casing body 30 are integrated.

  Subsequently, as shown in FIG. 2, the lower end portion of the welded portion 42 a of the lid body 40 is melted by a hot plate (not shown), and the hot plate (not shown) is provided along the periphery of the mounting hole FTb of the fuel tank FT. To be a welded portion FTd. The casing body 30 is inserted into the mounting hole FTb from below, and the welded portion 42a is pressed against the welded portion FTd. Thereby, since the welding part 42a and the welding part FTd are formed with the same resin material, both will weld each other when it solidifies by cooling. As described above, when the lid 40 is welded to the tank upper wall FTa, the inside of the fuel tank FT is secured with high sealing performance against the outside.

(4) Operation of the fuel cutoff valve 10 Next, the operation of the fuel cutoff valve 10 will be described. In FIG. 2, when the fuel level in the fuel tank FT is below a predetermined level, the float 50 is in the lowered position, and the connection passage 44a is opened to ensure ventilation between the fuel tank FT and the outside. . When the fuel level in the vicinity of the fuel shut-off valve 10 rises due to the vehicle swinging or tilting, the fuel vapor accumulated in the upper part of the fuel tank FT passes through the communication hole 32a (FIG. 3) and the valve chamber 20S. , Escape to the canister side through the connection passage 44a and the tube passage 43a. When the fuel level in the fuel tank FT reaches a predetermined level, the fuel flows into the valve chamber 20S through the communication hole 34a of the bottom wall portion 34. As a result, buoyancy is generated in the float 50 and the valve portion 52 is seated on the seal portion 44b to close the connection passage 44a and prevent the fuel from flowing out to the canister side. Accordingly, it is possible to prevent the fuel vapor from escaping from the fuel tank FT and the fuel from flowing out of the fuel tank FT due to the rise of the fuel liquid level in the fuel tank FT.

(5) Operation and effect of embodiment The following operation and effect are achieved by the configuration of the above embodiment.
(5) -1 Since the lid 40 is formed of the same high-density polyethylene as the fuel tank FT, it does not require a fastening member or the like, and can be easily fixed to the upper portion of the fuel tank FT by heat welding.

(5) -2 The seal portion 44b is formed integrally with the raised portion 41b of the lid body 40, and the connection passage 44a is closed by the valve portion 52 of the float 50 being seated, so that the inside of the fuel tank FT is exposed to the outside. And sealed. Therefore, the present embodiment does not require a sealing member and reduces the number of parts compared to the conventional technique in which a sealing portion is provided in the casing body and the casing body is assembled with a sealing member interposed in the casing body. Can do.

(5) -3 As shown in FIG. 6, since the seal portion 44 b is formed in the raised portion 41 b higher than the flat plate portion 41 a of the lid body 41, the sealing performance is not deteriorated due to fuel swelling. That is, fuel swelling occurs in the lid main body 41 due to the fuel vapor filled in the fuel tank FT. At this time, since the lid 40 is welded and restrained to the fuel tank FT, the flat plate portion 41a of the lid body 41 is curved so as to rise upward as indicated by a two-dot chain line, and is not circumferentially oriented. Uniform deformation may occur. The raised portion 41b is separated from the welded portion 42a constrained by the fuel tank FT, and is not easily affected by such uneven deformation of the flat plate portion 41a, and the fuel swells uniformly, so that the seal portion 44b has a large size. No change in shape. Therefore, the seal portion 44b is less affected by the shift of the central axis and the change of the shape due to the swelling of the fuel, and can maintain high sealing performance.

(5) -4 As shown in FIG. 3 and FIG. 4, the mounting means can easily assemble the casing body 30 and the lid body 40 and hold them firmly. That is, when the insertion portion 45 of the lid 40 is inserted into the holding gap 38S of the holding portion 36, the insertion portion 45 is held in the holding gap 38S, and the engaging claw 36d of the connecting means is engaged with the engaging hole 45a. In combination, the casing body 30 and the lid body 40 are easily connected. At this time, since the insertion portion 45 is abutted and supported by the rib 38 projecting from the holding portion 36, the casing body 30 is mounted without being inclined with respect to the lid body 40, and the float 50 is misaligned. Therefore, a stable lifting operation can be performed.

(5) -5 The mounting means holds firmly even if the lid 40 is larger than the casing body 30 and the fuel swells. That is, the lid 40 is made of high-density polyethylene and has a larger fuel swelling amount than the casing body 30 made of polyacetal. For this reason, even if the insertion part 45 formed in the lid body 40 expands due to fuel swelling from the holding part 36 of the casing body 30, the swollen part expands in the holding gap 38 </ b> S, and the casing body 30 tilts. Does not produce a strong force. Therefore, the casing body 30 is not rattled with respect to the lid body 40, and there is a problem associated with rattling, that is, the float 50 does not move up and down in a tilted state, and a stable opening / closing characteristic can be obtained. .

(5) -6 When the insertion portion 45 is inserted into the holding gap 38S, the rib 38 is easily pushed and elastically deformed by the insertion portion 45, so that the allowable range of the dimensional tolerance of the holding gap 38S can be set large.

(5) -7 The annular connecting part 36b of the holding part 36 has a structure in which the upper part of the support leg part 36a is connected in an annular shape, and holds the base of the insertion part 45. Compared with the structure formed by dividing the insertion portion 45, it is possible to suppress the insertion portion 45 from expanding with fuel swelling with a large force.

(5) -8 Since the engaging portion 36c and the engaging hole 45a constituting the connecting means are formed integrally with the annular connecting portion 36b and the insertion portion 45, respectively, the configuration of the mold can be simplified.

(6) Other Embodiments The present invention is not limited to the above-described embodiments, and can be implemented in various modes without departing from the scope of the invention.
(6) -1 In the above embodiment, as shown in FIG. 5, the rib 38 protrudes from the inner wall of the annular coupling portion 36b. May be provided on the inner wall of the insertion part or the outer wall of the side wall part, or may be provided from both members. Good.
(6) -2 In the above embodiment, the casing main body constituting the casing is integrally formed with the side wall portion and the bottom wall portion. However, the present invention is not limited to this, and the same effects can be obtained even if formed separately. .

It is a side view which shows a fuel cutoff valve. It is sectional drawing which shows a fuel cutoff valve. It is sectional drawing which decomposed | disassembled the fuel cutoff valve. It is the side view which decomposed | disassembled the fuel cutoff valve. FIG. 5 is a cross-sectional view taken along line 5-5 of FIG. It is explanatory drawing explaining the effect | action of a fuel cutoff valve.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fuel cutoff valve 20 ... Casing 20S ... Valve chamber 30 ... Casing main body 32 ... Side wall part 32a ... Communication hole 34 ... Bottom wall part 34a ... Communication hole 34b ... Spring receiving part 36 ... Holding part 36a ... Support leg part 36b ... Ring shape Connecting portion 36c ... engaging portion 36d ... engaging claw 36e ... slit 38 ... rib 38S ... holding gap 40 ... lid body 41 ... lid body 41a ... flat plate portion 41b ... raised portion 41c ... standing wall portion 41d ... top plate portion 42 ... flange 42a ... welded portion 43 ... tube portion 43a ... tube passage 44 ... passage formation portion 44a ... connection passage 44b ... seal portion 45 ... insertion portion 45a ... engagement hole 45b ... notch 50 ... float 50S ... float chamber 51 ... float Main body 52 ... Valve part 70 ... Spring FT ... Fuel tank FTa ... Tank upper wall FTb ... Mounting hole FTd ... Welding part

Claims (2)

A casing (20) having a valve chamber (20S) attached to an upper portion of the fuel tank (FT) and connected to the fuel tank (FT) and a connection passage (44a) connecting the valve chamber (20S) and the outside. And a float (50) stored in the valve chamber (20S) and opened and closed by the fuel level in the valve chamber (20S) to open and close the connection passage (44a),
The casing (20) includes a casing body (30) having a cylindrical side wall (32), and a lid (40) disposed on the upper side of the side wall (32).
The lid (40) is formed on a lid body (41) that covers a part of the upper opening of the side wall (32) and has the connection passage (44a), and an outer peripheral portion of the lid body (41). A weld portion (42a) that can be thermally welded to the upper portion of the fuel tank (FT), and a seal portion (44b) that is disposed facing the connection passage (44a) and on which the upper portion of the float (50) is seated. ,
The lid body (41) includes a flat plate portion (41a) that covers the outer peripheral portion of the upper opening of the casing main body (30), and a raised portion that arranges the seal portion (44b) above the flat plate portion (41a). (41b)
A fuel shut-off valve characterized by The fuel cutoff valve according to claim 1,
The raised portion (41b) is integrally formed on a cylindrical standing wall portion (41c) projecting upward from the flat plate portion (41a) and the upper portion of the standing wall portion (41c), and the sealing portion (44b). A fuel cutoff valve having a top plate portion (41d) provided with

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