JP2011110953A - Fuel shutoff valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel shutoff valve in which the fluctuation of the valve closing level of fuel due to the swelling of the fuel is reduced. <P>SOLUTION: This fuel shutoff valve 10 includes a casing 20 having a casing body 30 and a bottom member 35 which is disposed at the bottom of the casing body 30 and has an opening 38d, a float mechanism 50 for opening and closing a connection passage 31b by lifting according to the level of the fuel in a valve chamber 30S, and a spring 70. The bottom member 35 includes a bottom plate 36 having a spring support part 36a for supporting the bottom end of the spring 70 and flow holes 37a, 37b connected to the valve chamber 30S, a weld part 36b which is formed on the outer peripheral part of the bottom plate 36 and welded to the bottom end of the casing body 30, and a plurality of ridge-shaped upper surface ribs 39a which are radially disposed on the upper surface of the bottom plate 36 so as to extend radially outward from the center of the bottom plate 36 starting at the spring support part 36a to the inner peripheral side of the weld part 36b. <P>COPYRIGHT: (C)2011,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.

  Conventionally, for example, the technique of Patent Document 1 is known as this type of fuel cutoff valve. The fuel shut-off valve has a cylindrical casing body and a casing that has a bottom member that closes an opening at a lower portion of the casing body, forms a valve chamber, a float that is housed in the valve chamber, and is supported by the bottom member and closes the float When the valve is normally open, it ensures ventilation to the outside of the fuel tank (canister) and closes when the fuel level reaches the full tank level when refueling. The tank internal pressure is raised to activate the auto-stop by the refueling gun, and when the fuel level reaches the cut-off level when the vehicle is tilted, Prevents the outflow of fuel.

  However, the conventional fuel shut-off valve has a problem that due to secular change, the valve closing liquid level such as the full tank liquid level and the cutoff liquid level varies, and the fuel leaks due to the valve closing delay.

JP 2009-174413 A

  An object of the present invention is to provide a fuel cutoff valve that reduces variations in the cut-off liquid level, in view of solving the above-described problems of the prior art.

  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 is a fuel cutoff valve that is attached to the upper portion 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 cylindrical casing body that forms a valve chamber that communicates the inside of the fuel tank and the connection passage; and a bottom member that is disposed at a lower portion of the casing body and has an opening. The opening is the fuel tank. A casing formed so as to increase a differential pressure between the pressure in the fuel tank and the pressure in the valve chamber by being clogged with the fuel when the fuel level in the tank reaches a predetermined liquid level; ,
A float mechanism that is housed in the valve chamber and opens and closes the connection passage by being raised and lowered by a fuel liquid level in the valve chamber;
A spring supported by the bottom member and biasing the float mechanism in a valve closing direction;
With
The bottom member includes a spring support portion that supports a lower end of the spring and a bottom plate that has a flow hole connected to the valve chamber, and a weld portion that is formed on the outer periphery of the bottom plate and is welded to the lower end of the casing body. A support standing wall that protrudes from the upper surface of the outer peripheral portion of the bottom plate and is supported along the lower opening of the casing body, and is an upper surface of the bottom plate that radiates from the outer peripheral side of the spring support portion around the bottom plate. And an upper surface rib connected to the support upright wall.

  In Application Example 1, when fuel is supplied to the fuel tank using the fuel cutoff valve and the fuel level in the fuel tank reaches a predetermined level, the opening provided in the bottom member is the fuel that has reached the fuel level. By being blocked, the pressure in the fuel tank rises and the differential pressure between the pressure in the fuel tank and the pressure in the valve chamber increases. Due to this differential pressure, fuel flows into the valve chamber from the fuel tank through the introduction passage and the circulation hole. The fuel that has flowed up rises due to buoyancy and closes the connection passage, thereby blocking the fuel tank from the outside.

  Further, the bottom member is welded to the lower end of the casing body at the welded portion, that is, is fixed to the lower end of the casing body by being restrained by the casing body at the outer peripheral portion thereof. For this reason, when the bottom plate swells the fuel, a bending force is generated in a direction in which the central portion is lowered. However, since the plurality of upper surface ribs on the upper surface of the bottom plate are formed radially outward from the center, the planar shape is maintained under the restraining force against the warp of the bottom plate, and the position of the spring support portion is lowered. Deformation is reduced. In addition, the bottom member has a support standing wall supported by the lower part of the casing body, and the upper surface rib is connected to the support standing wall, so that the upper surface rib is designed to increase the connection strength of the root of the cantilever beam. It is possible to increase the resistance against warping of the bottom plate. Further, the support standing wall is supported by the lower part of the casing body, so that the influence of the warp of the upper surface of the bottom member can be made uniform and minimal in the circumferential direction. Accordingly, there is no variation in the liquid level to be closed due to the displacement of the spring support portion, and it is possible to prevent the fuel from leaking from the connection passage due to the delay in the operation of the float mechanism.

[Application examples 2 and 3]
The application example 2 may be configured to include a lower surface rib disposed on the lower surface of the bottom plate, radially outward from the center of the bottom plate and below the spring support portion. Application Example 3 can be configured such that the inner end of the upper surface rib and the outer end of the lower surface rib overlap in the radial direction. With this configuration, the mechanical strength of the bottom plate can be increased.

[Application Example 4]
The bottom member of Application Example 4 may be configured to include an introduction passage forming member that protrudes in a cylindrical shape downward from the outer peripheral portion of the bottom plate and forms an introduction passage connected to the flow hole. With this configuration, the valve closing liquid level can be appropriately set according to the position of the opening of the introduction passage forming member.

[Application Example 5]
The casing body of Application Example 5 communicates the valve chamber with the inside of the fuel tank, and when the fuel level reaches a predetermined level other than during refueling, the fuel is supplied according to the level in the fuel tank. A structure having a communication hole having a ventilation area for reducing the differential pressure so as to be led to the valve chamber can be employed. Such a communication hole can prevent the tank internal pressure of the fuel tank from rising above a predetermined level.

[Application Example 6]
In Application Example 6, the bottom member may be made of polyamide, and the casing main body may be made of polyamide having higher mechanical strength than the bottom member by mixing glass fiber. In addition, the casing body to which glass fiber is added by such material selection has less influence of fuel swelling, and the float mechanism can be raised and lowered without rattling, while the bottom member to which glass fiber is not added is described above. As described above, since the mechanical strength is ensured by the upper surface rib, it is possible to avoid problems associated with warpage due to fuel swelling.

It is a top view which shows the fuel cutoff valve with which the upper part of the fuel tank of the motor vehicle was mounted | worn. FIG. 2 is a cross-sectional view taken along line 2-2 in FIG. It is sectional drawing which decomposed | disassembled the fuel cutoff valve. It is the perspective view which fractured | ruptured the bottom member partially. It is a top view of a bottom member. It is a bottom view of a bottom member. It is a perspective view which decomposes | disassembles and shows the 1st valve part and 2nd valve part which comprise a float and a valve body. It is sectional drawing which decomposes | disassembles and shows the 1st valve part and 2nd valve part which comprise a float and a valve body. It is explanatory drawing explaining the effect | action of a float mechanism. It is explanatory drawing explaining operation | movement of a fuel cutoff valve. It is explanatory drawing explaining the effect | action of a bottom member. It is sectional drawing which shows the fuel cutoff valve concerning another Example.

  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 plan view showing a fuel cutoff valve 10 mounted on the upper part of a fuel tank of an automobile, and FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. The fuel tank FT includes a barrier layer formed from an ethylene vinyl alcohol copolymer (EVOH) and an outer layer formed from polyethylene (PE). A mounting hole FTb is formed in the tank upper wall FTa above the fuel tank FT, and the fuel cutoff valve 10 is mounted with its lower part protruding into the mounting hole FTb, and is connected to a canister via a communication pipe (not shown). It is connected to the. The fuel shut-off valve 10 is closed when the fuel in the fuel tank reaches the full tank liquid level FL1 at the time of refueling, and the tank internal pressure is increased so as to function as an automatic stop. When it reaches, the valve is closed to prevent the fuel from flowing out. Hereinafter, the configuration and operation of each part of the fuel cutoff valve 10 will be described.

(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 member 35, and a lid body 40. A space surrounded by the casing main body 30 and the bottom member 35 is a valve chamber 30S. A spring 70 is provided in the valve chamber 30S. The float mechanism 50 supported by the housing is housed. Here, the resin material of each component of the fuel cutoff valve 10 is selected as follows in consideration of the mechanical strength, the weldability, the fuel swelling property, and the like. That is, the outer layer and the inner layer of the lid body 40 are each formed of modified polyethylene and polyamide in consideration of weldability with the fuel tank FT. The casing body 30 is made of polyamide mixed with 30% glass fiber in consideration of fuel swellability. The bottom member 35 is made of polyamide mainly considering the weldability with the casing body 30. The float mechanism 50 is formed of polyacetal mainly considering fuel swellability and sealability.

  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 side wall portion 32, and a lower portion thereof is an opening 30a. A passage forming projection 31a is formed in the center of the ceiling wall 31 so as to project downward. A connection passage 31b is formed through the passage forming projection 31a. The valve chamber 30S side of the connection passage 31b is a seal portion 31c. A communication hole 32 a that connects the inside of the fuel tank FT and the valve chamber 30 </ b> S is formed in the upper portion of the side wall portion 32. Further, on the inner wall of the side wall portion 32, case-side guide portions 34 for guiding the float mechanism 50 are provided in eight rib shapes in the circumferential direction. The case side guide portion 34 includes a lower guide rib 34a formed at the lower portion of the casing body 30, and an upper guide rib 34b formed on the axial center side from the lower guide rib 34a.

  The bottom member 35 is a member for closing a part of the opening 30a of the casing body 30 and introducing fuel vapor and liquid fuel into the valve chamber 30S. 4 is a perspective view in which the bottom member 35 is partially broken, FIG. 5 is a plan view of the bottom member 35, and FIG. 6 is a bottom view of the bottom member 35. The bottom member 35 is provided with a disc-shaped bottom plate 36 disposed at the lower end of the casing body 30, a central protrusion 37 protruding from the central portion of the bottom plate 36, and a cylindrical projection downward from the outer peripheral portion of the bottom plate 36. And an introduction passage forming member 38, which are integrally formed. The bottom plate 36 has a spring support portion 36a that supports a spring 70 (FIG. 3) on its upper surface, a weld portion 36b that is laser welded to the flange 33d of the casing body 30, and an inner peripheral side of the weld portion 36b. And a support standing wall 36c fitted in the opening 30a at the lower part of the casing body 30. The support standing wall 36c is formed with a slit 36d for facilitating fitting into the opening 30a. The central projection 37 is formed with through holes 37a, and four through holes 37b are formed so as to surround the through holes 37a. These flow holes 37a and 37b are connected to the valve chamber 30S. The introduction passage forming member 38 includes a cylindrical portion 38a, a disk portion 38b whose diameter is increased from the lower end of the cylindrical portion 38a, and an introduction passage 38c formed in the cylindrical portion 38a. The disc portion 38b has an effect of preventing air entrainment entering the introduction passage 38c together with the liquid fuel. The introduction passage 38c is a passage that guides the fuel vapor and liquid fuel taken from the opening 38d at the lower end into the valve chamber 30S through the flow holes 37a and 37b.

  Upper and lower ribs 39a and 39b are formed on the upper and lower surfaces of the bottom plate 36, respectively. That is, as shown in FIG. 5, the upper surface rib 39a is a plurality of protrusions that are radially arranged from the center of the bottom plate 36 to the radially outer side and from the outer peripheral edge of the spring support portion 36a to the inner peripheral side of the welded portion 36b. Is formed. The outer end of the upper surface rib 39a is connected to the support standing wall 36c, and increases the mechanical strength of the upper surface rib 39a. As shown in FIG. 6, the lower surface rib 39 b is formed on the lower surface of the bottom plate 36 with four protrusions in the same direction as the upper surface rib 39 a and is disposed below the spring support portion 36 a that supports the lower end of the spring 70. Yes. The outer peripheral end of the lower surface rib 39b overlaps the inner end of the upper surface rib 39a in the radial direction.

  Returning to FIG. 3, the lid body 40 includes a lid main body 41, a tube body portion 42 projecting laterally from the center of the lid main body 41, and a flange 43 formed on the outer periphery of the lid main body 41. Is 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 through the connection passage 31b, and the other end is connected to a canister communication tube (not shown). An inner welding end 43a for welding the upper end of the outer peripheral portion of the casing body 30 is formed at the lower part of the lid body 41, and the outer side welded to the tank upper wall FTa of the fuel tank FT is formed at the lower end of the flange 43. A welded portion 43b is formed.

  The float mechanism 50 has a two-stage valve structure with improved restart valve characteristics, and includes a float 52 and a valve body 60 disposed on the float 52. The float 52 includes a first float portion 53 and a second float portion 54, which are assembled together. The first float unit 53 includes a first float body 53a. The second float portion 54 has a cylindrical shape and includes a second float body 54b having a storage hole 54a. The first float portion 53 is integrated with the first float portion 53 by being inserted into the storage hole 54a. A step portion on the outer peripheral portion of the first float main body 53 a serves as a spring support portion 53 b and supports the upper end of the spring 70. The spring 70 is disposed between the spring accommodation gap 52a (FIG. 3), which is a space between the first float portion 53 and the second float portion 54, and between the spring support portion 36a of the bottom member 35. I am passing.

  FIG. 7 is an exploded perspective view showing the float 52 and the first valve portion 61 and the second valve portion 65 constituting the valve body 60, and FIG. 7 is a cross-sectional view showing the vicinity of the valve body 60. A valve support 55 projects from the upper part of the first float body 53a. The valve support portion 55 is a portion that supports the valve body 60 so as to swing, and includes a support protrusion 56 that is a columnar protrusion. The upper surface of the support protrusion 56 is a flat support surface 56a. An annular protrusion 57 for preventing the valve body 60 from being removed is formed on the outer peripheral portion of the valve support portion 55.

  The valve body 60 includes a first valve portion 61 and a second valve portion 65, and is supported by the valve support portion 55 of the float 52 so as to be movable up and down and swingable. The first valve unit 61 includes a valve main body 62 having a bottomed cylindrical shape and a seat member 64 attached to the valve main body 62. The valve main body 62 includes an upper surface portion 62a and a cylindrical side wall 62b protruding from the outer peripheral portion of the upper surface portion 62a, and an inner space thereof serves as a support hole 62c. An attachment portion 62d for attaching the sheet member 64 is formed at the center of the upper surface portion 62a. In addition, four vent holes 62e for connecting the support holes 62c to the outside are formed in the outer periphery of the upper portion of the valve body 62. On the inner peripheral wall of the side wall 62b shown in FIG. 8, rib-shaped guide parts 62f are projected in four vertical directions at equal intervals in the circumferential direction, and guide the second valve part 65 so that it can be raised and lowered. Further, an engaging claw 62g for engaging with the second valve portion 65 is formed on the inner peripheral wall of the side wall 62b so as to be elastically deformable.

  The sheet member 64 includes a sheet portion 64a that is attached to and detached from the seal portion 31c (FIG. 4), a connection hole 64b that passes through the central portion of the sheet portion 64a and is connected to the support hole 62c, and a lower end portion of the connection hole 64b. The sheet portion 64c formed and a mounting portion 64d formed on the outer peripheral portion of the connection hole 64b are provided and are integrally formed of a rubber material. The seat member 64 is attached by being press-fitted into the attachment portion 62d of the valve main body 62 by the attachment portion 64d, and the seat portion 64a has a gap with respect to the upper surface portion 62a of the valve main body 62, so that the seal portion 31c is provided. When seated, it is elastically deformed to improve sealing performance.

  The second valve portion 65 includes a cylindrical second valve main body 66. The second valve main body 66 is formed with a guide portion 66a that is a bottomed cylinder that opens downward. The guide portion 66 a prevents the second valve portion 65 from being greatly inclined with respect to the float 52 by being inserted into the support protrusion 56 with a predetermined gap. A convex supported portion 66b that is slightly curved downward is formed at the center of the upper surface of the guide portion 66a. Since the supported portion 66b is placed on the support surface 56a of the float 52, the second valve portion 65 is supported so as to be able to swing with the support portion 55a as a fulcrum.

  Further, a second seal portion 66c is formed on the upper surface of the second valve body 66, and the second seal portion 66c is separated from the seat portion 64c of the first valve portion 61, whereby the connection hole 64b is formed. It is formed to open and close. At the lower part of the second valve body 66, four retaining claws 66d are formed. By engaging with the engaging claws 62g of the first valve part 61, the first valve part 61 is connected to the second valve part 65. It is supported so that it can be raised and lowered. An engagement claw 66e is formed on the inner wall of the second valve main body 66. By engaging with the annular protrusion 57 of the float 52, the second valve portion 65 is supported and lifted up and down with respect to the float 52. It has been removed.

  Further, the center of gravity of the valve body 60 is set below the supported portion 66b. As a configuration for this purpose, each of the first valve portion 61 and the second valve main body 66 has a cylindrical shape and extends downward from the supported portion 66b supported by the support surface 56a.

  FIG. 9 is an explanatory view for explaining the operation of the float mechanism 50. As shown in FIG. 9, it is assumed that the float 52 is inclined in the direction of the arrow due to the inclination of the vehicle. The second valve portion 65 has a curved convex support portion 66b supported by a support portion 55a that is a flat surface of the float 52. The sheet member 64 maintains a horizontal posture.

(3) Operation of the fuel shut-off valve 10 (3) -1 Operation during refueling As shown in FIG. 2, when fuel is supplied into the fuel tank FT by refueling, the fuel level in the fuel tank FT increases. The fuel vapor accumulated in the upper part of the fuel tank FT flows into the valve chamber 30S from the flow holes 37a and 37b through the introduction passage 38c of the introduction passage forming member 38. Further, the fuel vapor is released from the valve chamber 30S to the canister side through the connection passage 31b and the pipe passage 42a. When the fuel level in the fuel tank FT reaches the full tank level FL1 determined by the lower end of the introduction passage forming member 38, the fuel completely closes the opening 38d, thereby increasing the tank internal pressure of the fuel tank FT. To do. In this state, the differential pressure between the tank internal pressure and the pressure in the valve chamber 30S increases, and liquid fuel flows into the valve chamber 30S through the introduction passage 38c and the flow hole 37a, and the fuel level rises in the valve chamber 30S. .

  Then, as shown in FIG. 10, when the fuel level in the valve chamber 30S reaches the height h0, the upward force due to the buoyancy of the float 52 and the load of the spring 70 and the downward force due to the weight of the float mechanism 50 are lowered. Due to the balance with the force, the former exceeds the latter and the float mechanism 50 rises integrally, and the seat member 64 of the valve body 60 is seated on the seal portion 31c to close the connection passage 31b. As a result, the internal pressure of the tank rises, fuel accumulates in the fuel injection pipe, and when the fuel touches the fuel gun, the auto-stop is activated. As described above, when fuel is supplied to the fuel tank FT, it is possible to escape the fuel vapor from the fuel tank FT and to prevent the fuel from flowing out of the fuel tank FT.

  After the auto-stop, when the pressure in the valve chamber 30S and the tank internal pressure become the same pressure through the communication hole 32a and the fuel level in the valve chamber 30S decreases, the float 52 descends with its buoyancy reduced. As the float 52 descends, the float 52 pulls down the second valve portion 65 through the engagement between the annular protrusion 57 of the float 52 and the engagement claw 66e of the second valve portion 65, as shown in FIG. . Thereby, the 2nd seal | sticker part 66c leaves | separates from the sheet | seat part 64c, and opens the connection hole 64b. Due to the communication of the connection hole 64b, the pressure below the first valve portion 61 becomes the same pressure as the vicinity of the connection passage 31b. And the 2nd valve part 65 also pulls down the 1st valve part 61 through engagement with 66 d of retaining claws, and the engagement claw 62g. And when the 1st valve part 61 descends, the sheet | seat member 64 leaves | separates from the seal part 31c, and the connection channel | path 31b is opened. Thus, the two-stage valve structure including the second valve portion 65 and the first valve portion 61 functions to promote the improvement of the restart valve characteristics. At this time, since the seat portion 64c is separated from the second seal portion 66c and the connection hole 64b having a small passage area communicates first, the pressure at the lower portion of the first valve portion 61 is reduced and the first valve portion 61 is closed. The force in the valve direction is reduced, and therefore the restart valve characteristics are excellent.

(3) -2 Operation when the vehicle is tilted In FIG. 2, the fuel cutoff valve 10 is externally (canister) through the fuel tank FT through the communication hole 32a, and further through the valve chamber 30S, the connection passage 31b, and the pipe passage 42a. It is connected to and secures ventilation to the outside. When the fuel level to the fuel tank FT exceeds the full tank level FL1 due to the inclination of the vehicle or the like, the differential pressure between the tank internal pressure and the pressure in the valve chamber 30S does not increase compared to when refueling. Due to the phenomenon, the fuel in the fuel tank FT is not sucked into the valve chamber 30S, and thus the liquid level in the valve chamber 30S does not rise rapidly. Due to the inclination of the vehicle, the fuel gradually flows into the valve chamber 30S through the introduction passage 38c and the flow holes 37a and 37b beyond the cut-off liquid level FL2, and the liquid level in the valve chamber 30S reaches the height h0. When it reaches, the float mechanism 50 rises and the valve body 60 closes the connection passage 31b, thereby preventing the fuel from flowing out from the fuel tank FT.

(4) Actions and effects of the embodiment The following actions and effects are exhibited by the configuration of the above embodiment.
(4) -1 When fuel is supplied to the fuel tank FT using the fuel shut-off valve 10, the fuel level in the fuel tank reaches the full tank level FL1, and the opening 38d is closed with fuel. As the pressure in the fuel tank increases, the differential pressure between the tank internal pressure and the pressure in the valve chamber 30S increases, and the fuel flows into the valve chamber 30S through the introduction passage 38c and the flow holes 37a and 37b due to this differential pressure. The floated fuel 50 is lifted by buoyancy due to the inflowed fuel, and the connection passage 31b is closed by the valve body 60, thereby shutting off the fuel tank FT from the outside and further increasing the tank internal pressure of the fuel tank FT. Then, fuel can be accumulated in the fuel injection pipe, and the fuel can come into contact with the refueling gun so that the auto-stop can be activated. Thus, the bottom member 35 can determine the full liquid level at the opening 38d provided in the introduction passage forming member 38.

(4) -2 As shown in FIG. 11, the bottom member 35 is welded to the lower end of the casing main body 30 by the welding portion 36 b, that is, the bottom member 35 is restrained by the casing main body 30 at the outer peripheral portion thereof. It is fixed. For this reason, when the bottom plate 36 swells the fuel, a force that bends in the direction in which the central portion is lowered is generated. However, since the plurality of upper surface ribs 39a on the upper surface of the bottom plate 36 are formed radially outward from the center, the planar shape is maintained by receiving the restraining force against the warp of the bottom plate 36, and the position of the spring support portion 36a. Is reduced (denoted by the two-dot chain line in the figure). Therefore, the variation in the cutoff liquid level FL2 (see FIG. 10) due to the displacement of the spring support 36a is eliminated, and the fuel can be prevented from leaking from the connection passage 31b due to the operation delay of the float mechanism 50.

(4) -3 The upper surface rib 39a is connected to the support standing wall 36c at its outer end, and can increase the resistance against warping of the bottom plate 36 by the action of increasing the connection strength at the base of the cantilever. In addition, since the support standing wall 36c is fitted and supported by the opening 30a of the casing body 30, the influence of warping of the upper surface of the bottom plate 36 can be made uniform and minimal in the circumferential direction.

(4) -4 The casing body 30 and the bottom member 35 are both difficult to weld when using a polyamide mixed with glass fibers, but glass fibers are mixed only in the casing body 30; It can be surely welded to ensure airtightness. Further, the casing body 30 to which the glass fiber is added by such material selection is less affected by the fuel swelling, and the float mechanism 50 can be moved up and down without rattling, while the bottom member 35 to which the glass fiber is not added is As described above, since the mechanical strength is ensured by the upper surface rib 39a, it is possible to avoid problems associated with warpage due to fuel swelling.

(4) -5 The lower surface rib 39b formed on the lower surface of the bottom plate 36 is disposed below the spring support portion 36a, and only increases the mechanical strength for supporting the spring 70, and does not cause warping. Further, since the outer end of the lower surface rib 39b overlaps the inner end of the upper surface rib 39a in the radial direction, the overall mechanical strength of the bottom plate 36 can be increased.

(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.

  FIG. 12 is a sectional view showing a fuel cutoff valve 10B according to another embodiment. The present embodiment is characterized by the shape of the bottom member 35B. In other words, the outer peripheral portion of the bottom plate 36B of the bottom member 35B is provided with a cylindrical introduction passage forming member 38B that is formed to be longer downward than in the embodiment of FIG. When the bottom plate 35B warps due to fuel swelling, the bottom member 35B tends to expand into a skirt that increases as the introduction passage forming member 38B moves downward. , Variation in the full tank liquid level FL1 can be suppressed.

  The support standing wall formed on the bottom plate of the above embodiment is formed in a cylindrical shape along the outer peripheral portion of the bottom plate, and is formed by a plurality of arc standing walls divided in the circumferential direction, and the top rib is connected to each arc standing wall It may be.

DESCRIPTION OF SYMBOLS 10 ... Fuel cutoff valve 10B ... Fuel cutoff valve 20 ... Casing 30 ... Casing main body 30S ... Valve chamber 30a ... Opening 31 ... Ceiling wall part 31a ... Passage formation protrusion 31b ... Connection passage 31c ... Seal part 32 ... Side wall part 32a ... Communication Hole 33d ... Flange 34 ... Case side guide portion 34a ... Lower guide rib 34b ... Upper guide rib 35 ... Bottom member 35B ... Bottom member 36 ... Bottom plate 36B ... Bottom plate 36a ... Spring support portion 36b ... Welding portion 36c ... Support standing wall 36d ... Split 37 ... Central protrusions 37a, 37b ... flow holes 38 ... introducing passage forming member 38B ... introducing passage forming member 38a ... cylindrical portion 38b ... disc portion 38c ... introducing passage 38d ... opening 39a ... upper surface rib 39b ... lower surface rib 39Ba ... upper surface rib DESCRIPTION OF SYMBOLS 40 ... Lid 41 ... Lid main body 42 ... Tube part 42a ... Pipe channel | path 43 ... Flange 43a ... inner welding end 43b ... outer welding part 50 ... float mechanism 52 ... float 52a ... spring storage gap 53 ... first float part 53a ... first float body 53b ... spring support part 54 ... second float part 54a ... housing hole 54b ... 2nd float main body 55 ... Valve support part 55a ... Support part 56 ... Support protrusion 56a ... Support surface 57 ... Annular protrusion 60 ... Valve body 61 ... First valve part 62 ... Valve main body 62a ... Upper surface part 62b ... Side wall 62c ... Support hole 62d ... Mounting part 62e ... Vent hole 62f ... Guide part 62g ... engaging claw 64 ... Seat member 64a ... Sheet part 64b ... Connection hole 64c ... Seat part 64d ... Mounting part 65 ... Second valve part 66 ... Second valve Main body 66a ... Guide part 66b ... Supported part 66c ... Second seal part 66d ... Retaining claw 66e ... engaging claw 70 ... Spring FT ... Fuel tank FT a ... Tank upper wall FTb ... Mounting hole

Claims (6)

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, thereby disconnecting the fuel tank (FT) from the outside. ,
A cylindrical casing body (30) that forms a valve chamber (30S) that communicates the inside of the fuel tank (FT) with the connection passage (31b), and an opening ( 38d), and when the fuel level in the fuel tank reaches a predetermined level (FL1) and the opening (38d) is closed with fuel, A casing (20) formed to increase a differential pressure between the pressure in the fuel tank and the pressure in the valve chamber (30S);
A float mechanism (50) housed in the valve chamber (30S) and opened and closed by the fuel level in the valve chamber (30S) to open and close the connection passage (31b);
A spring (70) supported by the bottom member (35) and biasing the float mechanism (50) in the valve closing direction;
With
The bottom member (35) includes a spring support (36a) that supports a lower end of the spring (70) and a bottom plate (36) having flow holes (37a, 37b) connected to the valve chamber (30S), A welded portion (36b) formed on the outer peripheral portion of the bottom plate (36) and welded to the lower end of the casing main body (30); and a casing main body (30) provided on the upper surface of the outer peripheral portion of the bottom plate (36). A plurality of radial protrusions centering on the bottom plate (36) from the outer peripheral side of the spring support portion (36a) on the upper surface of the support plate (36c) supported along the lower opening of the bottom plate (36) A fuel cutoff valve, comprising an upper surface rib (39a) provided and connected to the support standing wall (36c). The fuel cutoff valve according to claim 1,
A fuel cutoff valve having a lower surface rib (39b) disposed on the lower surface of the bottom plate (36), radially outward from the center of the bottom plate (36) and below the spring support (36a). The fuel cutoff valve according to claim 2,
A fuel cutoff valve in which an inner end of the upper surface rib (39a) and an outer end of the lower surface rib (39b) overlap in a radial direction. The fuel cutoff valve according to any one of claims 1 to 3,
The bottom member (35) protrudes in a cylindrical shape downward from the outer peripheral portion of the bottom plate (36) and forms an introduction passage (38c) connected to the flow holes (37a, 37b). (38) The fuel cutoff valve provided with. The fuel cutoff valve according to any one of claims 1 to 4,
The casing body (30) communicates the valve chamber (30S) and the fuel tank (FT), and supplies fuel when the fuel level reaches a predetermined level (FL1) except during refueling. A fuel shut-off valve provided with a communication hole (32a) having a ventilation area for reducing the differential pressure so as to lead to the valve chamber (30S) as the liquid level in the fuel tank (FT) rises. The fuel cutoff valve according to any one of claims 1 to 5,
The fuel cutoff valve, wherein the bottom member (35) is made of polyamide, and the casing body (30) is made of polyamide having a mechanical strength higher than that of the bottom member (35) by mixing glass fibers.

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