JP2010274732A - Fuel cutoff valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cutoff valve 10 which prevents operation delay of a float by suppressing the entry of bubbles mixed in a fuel into a valve chamber 30S without increasing the number of parts. <P>SOLUTION: The fuel cutoff valve 10 includes a casing 20, which comprises a casing body 30 that forms the valve chamber 30S and a bottom member 35 having an opening 37b, and a float mechanism 50 accommodated in the valve chamber 30S. The bottom member 35 includes: a bottom plate 36, in which a circulation hole 36a is formed penetratingly; an introduction passage forming member 37, which forms an introduction passage 37a that connects the inside of a fuel tank to the circulation hole 36a and which has the opening 37b at lower part thereof; and a plurality of ribs 37c, which are provided protrusively in the vertical direction on the inner wall of the introduction passage forming member 37 to eliminate bubbles by enlarging contact areas with the bubbles in the fuel. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a fuel cutoff valve that is attached to an 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.

  Conventionally, a connection passage for allowing fuel evaporative gas to escape to the canister is provided in the upper portion of the fuel tank, and a fuel cutoff valve is mounted in this connection passage. The fuel shut-off valve generally contains a float that moves up and down with increasing or decreasing buoyancy depending on the fuel level in the valve chamber, and a valve body that opens and closes a valve seat is provided above the float. When the fuel level in the fuel tank rises, the float increases buoyancy and the valve body rises integrally with the float, thereby closing the connection passage and preventing the fuel from flowing out.

  In such a fuel shut-off valve, a large amount of air bubbles generated in the atmosphere or inlet (fuel injection pipe) entrained from the fuel supply port may be mixed in the fuel in the fuel tank during refueling. When these bubbles enter the valve chamber of the fuel shut-off valve, the buoyancy generated in the float is reduced, causing a delay in the operation of the float, and there is a problem that fuel leaks from the connection passage to the canister side. It was. In order to solve such a problem, a configuration is known in which bubbles are eliminated by providing a filter in the opening (Patent Document 1). However, the filter has a problem that the number of parts is increased, the assembly process is increased, and the productivity is not good.

JP2007-327417A

  The present invention provides a fuel cutoff valve that suppresses the invasion of bubbles mixed in fuel and prevents the delay of float operation, without increasing the number of parts, in light of solving the above-described problems of the prior art. For the purpose.

  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 part of the 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 casing main body that forms a valve chamber that communicates the inside of the fuel tank and the connecting passage; and a bottom member that is disposed at a lower portion of the casing main body and has an opening. 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 reaches a predetermined level;
A float that is housed in the valve chamber and moves up and down by increasing or decreasing buoyancy depending on the fuel level in the valve chamber, and a valve portion that is provided above the float and opens and closes the connection passage when the float moves up and down. A float mechanism;
With
The bottom member is disposed below the valve chamber and supports the float mechanism and has a through hole formed therethrough, and is provided in a cylindrical shape from the outer periphery of the bottom plate and connects the inside of the fuel tank to the through hole. And an introduction passage forming member for forming an introduction passage having the opening in the lower portion thereof, and a plurality of ribs provided on the inner wall of the introduction passage formation member in the vertical direction to increase the contact area with the fuel bubbles. And the introduction passage is disposed below the flow hole without detouring and has a larger passage area than the flow hole.

  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 is blocked with the fuel that has reached the fuel level. Then, 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 floated fuel is lifted by buoyancy due to the inflowed fuel, and the connection passage is closed at the valve portion, thereby shutting off the fuel tank from the outside and preventing the fuel from flowing out from the fuel tank.

  Further, when the above-described differential pressure is generated in the fuel shut-off valve, it is caught in the rapid flow of liquid fuel, and surrounding bubbles try to flow in a large amount into the introduction passage of the bottom member. When bubbles enter the introduction passage, many bubbles are generated near the surface of the liquid fuel, and in order to reduce the surface tension, the bubbles come into contact with ribs protruding from the inner wall of the introduction passage formation member. But rises. And most of the bubbles rising along the ribs are compressed and disappeared by the hydraulic pressure when they hit the lower surface of the bottom plate, and are prevented from flowing into the valve chamber from the flow holes. That is, the rib has an effect of sufficiently suppressing the intrusion of bubbles into the valve chamber, and prevents the buoyancy generated in the float due to the bubbles and delaying the operation of the valve element. Therefore, it is possible to prevent the fuel from leaking from the connection passage.

  Since these ribs are a plurality of protrusions integrally formed on the inner wall of the introduction passage forming member, the number of parts does not increase and the number of assembling steps does not increase as in the filter described in the prior art.

[Application Example 2]
The bottom plate of Application Example 1 may be configured to protrude downward from the peripheral edge of the flow hole and include a protrusion for eliminating the fuel bubbles. The protrusion is extinguished by applying a partial compressive force to the bubbles just before the bubbles enter the valve chamber from the flow hole. Therefore, inflow of bubbles into the valve chamber can be further suppressed. Further, the protrusion serves as a barrier when bubbles enter the valve chamber through the flow hole, and prevents the bubbles from entering the valve chamber.

[Application Example 3]
In Application Example 3, the inner wall of the introduction passage forming member of Application Example 1 is not provided with a plurality of ribs on the protrusions in the vertical direction, and the bottom plate protrudes downward from the peripheral edge portion of the flow hole, It is the structure which has the processus | protrusion for eliminating the bubble. This configuration can also reduce the amount of bubbles flowing into the valve chamber.

[Application Examples 4 and 5]
The bottom plate of Application Example 4 has a configuration in which a lower surface facing the introduction passage is an inclined surface that is inclined downward toward the flow hole. Even with this configuration, when the bubbles are directed from the inner wall of the introduction passage forming member to the flow hole, the bubbles are sufficiently extinguished by receiving a large compressive force on the inclined surface. Therefore, the amount of bubbles flowing into the valve chamber can be reduced. In this configuration, it is possible to further increase the disappearance of bubbles by providing ribs on the inner wall of the introduction passage forming body.

It is a schematic block diagram which shows the fuel supply apparatus of the fuel tank of a motor vehicle. It is sectional drawing which shows the fuel cutoff valve which concerns on one Example of this invention. It is sectional drawing which decomposed | disassembled the fuel cutoff valve. It is the perspective view which fractured | ruptured the bottom member partially. FIG. 5 is a cross-sectional view taken along line 5-5 in FIG. It is the perspective view which decomposed | disassembled the valve body. It is sectional drawing which decomposed | disassembled the 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 explaining the vicinity of the bottom member concerning another Example. It is sectional drawing explaining the vicinity of the bottom member 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 Tank FT FIG. 1 is a schematic configuration diagram illustrating a fuel tank fueling device for an automobile. As shown in the drawing, 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 fuel injection pipe IP is connected to the upper part of the fuel tank FT. The fuel injection pipe IP includes an injection port IPa that is opened and closed by a fuel cap, and fuel is supplied from the fuel gun to the fuel tank FT through the injection port IPa. Further, a mounting hole FTc is formed in the tank upper wall FTa at the upper part of the fuel tank FT, and the fuel cutoff valve 10 is mounted in a state where the lower part thereof enters the mounting hole FTc. The fuel cutoff valve 10 is connected to the canister CT through the canister communication pipe CP. The fuel shut-off valve 10 functions to prevent the canister from flowing into the canister when the fuel in the fuel tank rises to a predetermined liquid level FL1 during refueling and to function as an auto stop. 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 FIG. 2 is a cross-sectional view showing the fuel cutoff 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.

  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. The side wall portion 32 is formed with a first communication hole 32a that connects the inside of the fuel tank FT and the valve chamber 30S. 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 four circumferential rib shapes. 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, and FIG. 5 is a cross-sectional view taken along line 5-5 in FIG. The bottom member 35 is integrally formed with a bottom plate 36 and a cylindrical introduction passage forming member 37 projecting from the outer peripheral portion of the bottom plate 36, and is formed at the lower end of the casing body 30 (FIG. 3) at the outer peripheral portion of the bottom plate 36. It is welded. A flow hole 36 a is formed through the center of the bottom plate 36. A protrusion 36b is provided on the peripheral edge of the flow hole 36a so as to face downward and have a sharp tip. Further, on the upper surface of the bottom plate 36, a spring support portion 36c for supporting the lower end of the spring 70 (FIG. 3) is formed. The introduction passage forming member 37 includes an introduction passage 37a. The introduction passage 37a is a passage that guides the fuel vapor and liquid fuel taken in from the opening 37b at the lower end into the valve chamber 30S through the flow hole 36a, and is disposed without bypassing the flow hole 36a and the flow hole 36a. A larger passage area is formed. In addition, a plurality of ribs 37 c provided on the protrusion in the vertical direction are formed on the inner wall of the introduction passage forming member 37. A plurality of ribs 37c are formed at predetermined intervals in the circumferential direction (eight locations in the figure), and have the effect of extinguishing bubbles BB that have entered the introduction passage 37a together with the liquid fuel, as will be described later.

  Returning to FIG. 3, the lid body 40 includes a lid body 41, a tubular body portion 42 projecting laterally from the center of the lid body 41, and a flange 43 formed on the outer periphery of the lid body 41. It is integrally formed. The tube portion 42 is formed with a lid side passage 42a. One end of the lid side passage 42a is connected to the valve chamber 30S of the casing body 30 through the connection passage 31b, and the other end is connected to the canister communication pipe CP. Is done. 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. 2), which is a space between the first float portion 53 and the second float portion 54, and between the spring support portion 36c of the bottom member 35. I am passing.

  6 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. 7, rib-shaped guide portions 62f are projected in four vertical directions at equal intervals in the circumferential direction, and guide the second valve portion 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. 3), 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. Further, a spring 68 is interposed between the annular protrusion 57 of the float 52 and the bottom surface of the valve body 60, and the float 52 supports the valve body 60 via the spring 68.

  FIG. 8 is an explanatory view for explaining the operation of the float mechanism 50. As shown in FIG. 8, 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 cutoff valve 10 Next, the operation of the fuel cutoff valve 10 will be described. As shown in FIGS. 1 and 2, when fuel is supplied into the fuel tank FT by refueling, the fuel vapor that has accumulated in the upper portion of the fuel tank FT is introduced as the fuel level in the fuel tank FT rises. The fluid flows from the opening 37b of the passage forming member 37 through the introduction passage 37a into the valve chamber 30S through the flow hole 36a. Further, the fuel vapor is released from the valve chamber 30S to the canister CT side through the connection passage 31b and the lid side passage 42a. When the fuel liquid level in the fuel tank FT reaches the predetermined liquid level FL1 in the opening 37b, the fuel completely closes the opening 37b, thereby increasing the tank internal pressure of the fuel tank FT. 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 37a and the flow hole 36a, and the fuel level rises in the valve chamber 30S. .

  As shown in FIG. 9, when the fuel level in the valve chamber 30S reaches the height h0, the buoyancy of the float 52 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 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. At this time, when fuel accumulates in the fuel injection pipe IP (FIG. 1) and the fuel touches the fuel supply gun, the auto-stop is activated. Thereby, at the time of refueling 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.

  On the other hand, when the fuel in the fuel tank FT is consumed and the fuel level is lowered, 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.

(4) Operation and effect of the embodiment In addition to the above-described effect, the configuration of the above embodiment provides the following effect.
(4) -1 According to this embodiment, when the fuel is supplied to the fuel tank FT using the fuel cutoff valve 10 and the fuel liquid level in the fuel tank reaches the predetermined liquid level FL1, the opening 37b becomes the fuel liquid. Since the internal pressure of the fuel tank FT rises by being blocked by the fuel that has reached the upper limit, the auto-stop can be activated. Further, if the pressure difference between the tank internal pressure and the pressure in the valve chamber 30S increases due to the increase in the pressure in the fuel tank, the pressure difference causes the introduction passage of the introduction passage forming member 37 of the bottom member 35 from the fuel tank FT. The fuel flows into the valve chamber 30S through 37a and the flow hole 36a. The floated fuel 50 is lifted by the buoyancy due to the inflowed fuel, and the connection passage 31b is closed by the valve body 60, so that the fuel tank FT is shut off from the outside, and the fuel flows out from the fuel tank FT to the outside. To prevent. That is, the bottom member 35 is provided with the introduction passage forming member 37 at the lower portion of the casing body 30, and the full liquid level can be determined by the opening 37 b at the lower end of the introduction passage forming member 37.

(4) -2 In the fuel shut-off valve 10, when a differential pressure between the tank internal pressure and the pressure in the valve chamber 30S is generated, as shown in FIG. Bubbles BB tend to flow into the introduction passage 37a of the bottom member 35 in large quantities. The bubbles BB are generated in the vicinity of the liquid level of the liquid fuel when entering the introduction passage 37a, and are projected from the inner wall of the introduction passage forming member 37 in order to reduce the surface tension. It rises in contact with the rib 37c. Many of the bubbles BB rising along the ribs 37c are compressed by liquid pressure when they hit the lower surface of the bottom plate 36, disappear and become liquid fuel, and are returned to the introduction passage 37a. The flow into the chamber 30S is suppressed. That is, the rib 37c has an effect of sufficiently suppressing the intrusion of the bubble BB into the valve chamber 30S, and prevents the buoyancy generated in the float 52 from being lowered due to the bubble BB and delaying the operation of the valve body 60. . Therefore, it is possible to prevent the fuel from leaking from the connection passage 31b.

(4) -3 The protrusion 36b of the bottom plate 36 is projected at an acute angle downward toward the hole peripheral edge of the flow hole 36a, and the bubble partially enters the valve chamber 30S before entering the valve chamber 30S from the flow hole 36a. Appropriate compression force is applied to eliminate bubbles. Therefore, the protrusion 36b has a function of further suppressing the inflow of the bubble BB into the valve chamber 30S. Further, the protrusion 36b serves as a barrier when air bubbles enter the valve chamber 30S through the flow hole 36a, and prevents the air from entering the valve chamber 30S.

(4) -4 One through hole 36a is formed in the center of the bottom plate 36, and the passage area is the same as or larger than the passage area of the connection passage 31b (FIG. 3). Air bubbles are less likely to be generated than those in which a plurality of holes are formed, and the airflow resistance that is rate limiting with respect to the connection passage 31b is not increased.

(4) -5 Since the rib 37c is a plurality of protrusions integrally formed on the inner wall of the introduction passage forming member 37, it is assembled without increasing the number of parts as in the filter described in the prior art. There is no increase in man-hours.

(4) -6 A known fuel cutoff valve having a two-stage float structure, that is, a configuration in which a lower float is arranged in a space corresponding to the introduction passage 37a is also known. It cannot be avoided that a large amount of bubbles flow through the narrow space between the introduction passage forming member and the valve chamber through the flow hole. However, the introduction passage 37a of the introduction passage forming member 37 of the present embodiment is not a narrow space so as to generate a lot of bubbles, and also functions as a buffer chamber for eliminating the bubbles, so that the bubbles flow into the valve chamber 30S. Suppress.

(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. 11 is a cross-sectional view illustrating the vicinity of a bottom member 35B according to another embodiment. In the present embodiment, only the protrusion 36Bb protruding downward is provided on the peripheral edge of the flow hole 36Ba of the bottom plate 36B without providing a plurality of ribs of the protrusion in the vertical direction on the inner wall of the introduction passage forming member 37B. It is characterized by the structure provided. As described above, as a means for extinguishing the bubbles, even with only the protrusion 36Bb, it is possible to obtain a sufficient effect of eliminating the bubbles by making the tip shape an acute angle or making it a comb tooth.

  FIG. 12 is a cross-sectional view illustrating the vicinity of a bottom member 35C according to still another embodiment. In the present embodiment, the bottom surface of the bottom plate 36C is configured as an inclined surface 36Cd that is inclined downward toward the flow hole 36Ca. Even with this configuration, when the bubbles are directed from the inner wall of the introduction passage forming member 37C toward the flow hole 36Ca, it is possible to sufficiently obtain an action of disappearing by receiving a large compressive force at the inclined surface 36Cd. In addition, you may comprise so that the disappearance of a bubble may be increased further by providing a rib (example of FIG. 1) in the inner wall of the introduction channel | path formation member 37C concerning a present Example.

  The shape of the introduction passage forming member is not particularly limited as long as it can be provided with ribs and protrusions. The shape of the introduction passage forming member is not limited to a cylindrical shape as in the embodiment of FIG. By reducing the passage area of the opening 37Bb as a small-diameter portion having a smaller diameter at the lower portion, the present invention can also be applied to a shape that can increase the detection accuracy of the full liquid level.

DESCRIPTION OF SYMBOLS 10 ... 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 ... Sealing part 32 ... Side wall part 32a ... 1st communicating hole 34 ... Case side guide part 34a ... Lower guide rib 34b ... Upper guide rib 35 ... Bottom member 35B ... Bottom member 35C ... Bottom member 36 ... Bottom plate 36B ... Bottom plate 36C ... Bottom plate 36a ... Distribution hole 36b ... Projection 36c ... Spring support part 36Ba ... Distribution hole 36Bb ... Projection 36Ca ... Flow hole 36Cd ... Inclined surface 37 ... Introduction passage forming member 37B ... Introduction passage forming member 37C ... Introduction passage forming member 37a ... Introduction passage 37b ... Opening portion 37c ... Rib 37Bb ... Opening portion 40 ... Cover body 41 ... Lid Main body 42 ... Tube part 42a ... Cover side passage 43 ... Flange 43a ... Internal weld end 43b ... Outside Side welded portion 50 ... Float mechanism 52 ... Float 52a ... Spring storage gap 53 ... First float portion 53a ... First float body 53b ... Spring support portion 54 ... Second float portion 54a ... Storage hole 54b ... Second float body 55 ... Valve support portion 55a ... support portion 56 ... support projection 56a ... support surface 57 ... annular projection 60 ... valve element 61 ... first valve portion 62 ... valve body 62a ... upper surface portion 62b ... side wall 62c ... support hole 62d ... attachment portion 62e ... Vent hole 62f ... Guide part 62g ... Engagement claw 64 ... Sheet member 64a ... Seat part 64b ... Connection hole 64c ... Seat part 64d ... Mounting part 65 ... Second valve part 66 ... Second valve body 66a ... Guide part 66b ... supported part 66c ... second seal part 66d ... retaining claw 66e ... engagement claw 68 ... spring 70 ... spring CT ... canister CP ... Nista communication pipe IP ... Fuel injection pipe IPa ... Injection port FT ... Fuel tank FTa ... Tank upper wall FTc ... Mounting hole

Claims (5)

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 casing body (30) that forms a valve chamber (30S) that communicates the inside of the fuel tank (FT) and the connection passage (31b), and an opening (37b) that is disposed at a lower portion of the casing body (30). And the opening (37b) is closed by the fuel when the fuel level in the fuel tank (FT) reaches a predetermined level (FL1). A casing (20) formed to increase the differential pressure between the pressure in the fuel tank (FT) and the pressure in the valve chamber (30S);
A float (52) that is housed in the valve chamber (30S) and moves up and down by increasing or decreasing buoyancy depending on the fuel level in the valve chamber (30S), and the float (52) provided above the float (52). A float mechanism (50) having a valve portion that opens and closes the connection passage (31b) by moving up and down;
With
The bottom member (35) is disposed below the valve chamber (30S), supports the float mechanism (50) and has a through hole (36a) formed therein, and a bottom plate (36) of the bottom plate (36). An introduction passage forming member (37) which is provided in a cylindrical shape from the outer peripheral portion and connects the inside of the fuel tank to the flow hole (36a) and forms an introduction passage (37a) having the opening (37b) at the lower portion thereof; A plurality of ribs (37c) provided on the inner wall of the introduction passage forming member (37) in the vertical direction to increase the contact area with the fuel bubbles, and the introduction passage (37a) 36a) A fuel shut-off valve, which is arranged below the bypass hole 36a) and has a larger passage area than the flow hole (36a). The fuel cutoff valve according to claim 1,
The bottom plate (36) is a fuel shut-off valve having a protrusion (36b) protruding downward from a peripheral edge of the flow hole (36a) and extinguishing the fuel bubbles. In a fuel cutoff 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 to cut off communication between the fuel tank and the outside.
A casing body that forms a valve chamber that communicates the inside of the fuel tank and the connection passage; and a bottom member (35B) that is disposed at a lower portion of the casing body and has an opening. A casing formed so as to increase a pressure difference 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 that is housed in the valve chamber and moves up and down by increasing or decreasing buoyancy depending on the fuel level in the valve chamber, and a valve portion that is provided above the float and opens and closes the connection passage when the float moves up and down. A float mechanism;
With
The bottom member (35B) is disposed in the lower part of the valve chamber, supports the float mechanism, and has a bottom plate (36B) penetrating through the flow hole (36Ba), and is cylindrical from the outer periphery of the bottom plate (36B). An introduction passage forming member (37B) that is provided and connects the inside of the fuel tank to the circulation hole (36Ba) and forms an introduction passage having the opening at a lower portion thereof, and the circulation hole (36Ba) of the bottom plate (36B). ) Has a protrusion (36Bb) that protrudes downward and extinguishes the bubbles of the fuel, and the introduction passage is arranged without detouring below the circulation hole (36Ba). And a passage area equal to or larger than the passage area of the flow hole (36Ba). In a fuel cutoff 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 to cut off communication between the fuel tank and the outside.
A casing body that forms a valve chamber that communicates the inside of the fuel tank and the connection passage; and a bottom member (35C) that is disposed at a lower portion of the casing body and has an opening. A casing formed so as to increase a pressure difference 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 that is housed in the valve chamber and moves up and down by increasing or decreasing buoyancy depending on the fuel level in the valve chamber, and a valve portion that is provided above the float and opens and closes the connection passage when the float moves up and down. A float mechanism;
With
The bottom member (35C) is disposed in the lower part of the valve chamber, supports the float mechanism, and has a bottom plate (36C) formed through the flow hole (36Ca), and a cylindrical shape from the outer periphery of the bottom plate (36C). And an introduction passage forming member (37C) for forming an introduction passage having an opening in the lower portion thereof connected to the flow hole (36Ca) in the fuel tank, and facing the introduction passage of the bottom plate (36C). The fuel cutoff valve, wherein the lower surface is an inclined surface (36Cd) that is inclined downward toward the flow hole (36Ca). The fuel cutoff valve according to claim 4,
A fuel cutoff valve provided with a plurality of ribs provided on a plurality of protrusions in the vertical direction on the inner wall of the introduction passage forming member to increase the contact area with the fuel bubbles.

Images