JP2007032507A - Fuel shut-off valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel shut-off valve 10 which has a small change in valve closing liquid level with a temperature change in a fuel tank and which has improved float forming accuracy and improved productivity. <P>SOLUTION: The fuel shut-off valve 10 comprises a casing 20 as part of a valve chest 30S, the float 52 elevatably stored in the valve chest 30S, and a spring 70 for supporting the float 52. The float 52 consists of a first float part 53 and a second float part 57 assembled together. The first float part 53 has an upper valve element 60 for opening/closing a connection passage 31b and a spring supporting portion 53a for supporting the spring 70 at one end. The second float part 57 is integrated with the first float part 53 to form a spring storage clearance 53b between the first float part 53 and itself along the axial direction. The spring storage clearance 53b is formed so that the spring 70 supported at one end by the spring supporting portion 54c is arranged therein. <P>COPYRIGHT: (C)2007,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, Patent Documents 1 and 2 are known as this type of fuel cutoff valve. The fuel shut-off valve is mounted on the upper part of the fuel tank, and is moved up and down by increasing / decreasing buoyancy in the valve chamber of the casing provided with a connection passage connected to the outside (canister) and the valve chamber of the casing. With a float. Then, the float rises due to an increase in buoyancy due to the rise in the fuel level in the fuel tank, thereby closing the connection passage and preventing the fuel from flowing out.

  The float of the conventional fuel cutoff valve is formed in a thin cup shape provided with a buoyancy chamber that opens downward, thereby preventing sink marks that are likely to occur during injection molding of the float and increasing the molding accuracy. In such a cup-shaped float, the buoyancy chamber is sealed when the fuel level rises above the lower end of the float. The air in the sealed buoyancy chamber expands and contracts as the temperature in the fuel tank changes, changing the buoyancy of the float. For this reason, the fuel shut-off valve has a problem that the valve closing liquid level varies due to a temperature change in the fuel tank. In order to solve this problem, when the buoyancy chamber is reduced, the float not only deteriorates the molding accuracy due to resin sink marks during injection molding, but also takes a long time to cool down, reducing productivity. There was a problem to do.

JP 2004-308838 A Japanese Utility Model Publication No.4-1547.

  The present invention is based on solving the above-described problems of the prior art, and the fluctuation of the valve closing liquid level is small due to the temperature change in the fuel tank, the float molding accuracy can be increased, and the fuel shut-off excellent in productivity. The purpose is to provide a valve.

The present invention made to solve the problems
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 forming a valve chamber communicating the inside of the fuel tank and the connection passage;
A float that is housed in the valve chamber, and opens and closes the connection passage by raising and lowering the buoyancy according to the fuel level in the valve chamber; and
A spring for biasing the float in the valve closing direction;
With
The float is
A first float part having a valve part for opening and closing the connection passage;
A spring housing that is formed so as to surround an outer peripheral portion of the first float portion, is integrated with the first float portion, and is located along the ascending / descending direction between the first float portion and the spring. A second float part forming a gap;
It is characterized by having.

When fuel is supplied to a fuel tank using the fuel cutoff valve according to the present invention and reaches a predetermined liquid level in the fuel tank, the float rises by buoyancy due to the fuel flowing into the valve chamber. When the float rises, the valve portion closes the connection passage, thereby blocking the fuel tank from the outside and preventing the fuel from flowing out from the fuel tank.
In addition, the float is composed of a plurality of members including the first float portion and the second float portion, that is, the first float portion having the valve portion is integrated with the second float portion to thereby form the second float portion. Buoyancy can be reliably increased by the capacity. In addition, the first float portion does not need to have a thick cup shape to increase buoyancy, and when formed by injection molding, sink marks near the valve portion of the first float portion can be reduced, Molding accuracy can be increased. In addition, in order to increase the buoyancy, the float can be assembled with the second float portion integrally with the first float portion, so that the sealed chamber in which the gas accumulates can be made smaller or eliminated. There is no fluctuation in buoyancy, and fluctuation in valve closing liquid level can be reduced.

Furthermore, when forming a float by resin injection molding, when forming a space for housing a spring inside the float as in the prior art, in order to make the space as small as possible, the outer shape of the spring must be It is preferable to copy and make a slightly larger cylindrical space. However, in order to form such a space, it is necessary to provide a narrow cylindrical mold, and to provide a cooling means having a thin cooling passage in order to cool the inside of the cylindrical shape quickly. Such a cooling means is difficult in terms of mold production. However, the present invention does not require such a mold because the float is formed of two members, the first float portion and the second float portion, and a spring accommodating gap is provided between them. That is, the first float part may be formed with emphasis on molding accuracy of the valve part and the like, and the arrangement of the cooling means is not limited by the shape. In addition, the second float portion only needs to mainly consider an increase in buoyancy, that is, both members do not have to have a shape that requires a long time for cooling. Therefore, the injection molding cycle can be shortened and the productivity is excellent.
Furthermore, the space for arranging the springs is not only simplified by providing the spring accommodating gap between the first float part and the second float part, but also the buoyancy of the float accompanying the temperature change described above. It does not have to be a shape that causes fluctuations.

As a preferred aspect of the present invention, the first float part and the second float part can be configured to be integrated by an engaging means using an engaging claw and an engaging hole. With this configuration, the assembly work of the first float part and the second float part can be simplified.
Further, the spring accommodating gap can be connected to the outside of the float. With this configuration, even if the fuel goes up the spring storage gap due to capillary action, the fuel is quickly discharged from the spring storage gap, so that the apparent weight of the float does not change and the valve closing liquid level changes. Not a factor.

As a preferred aspect of the float, the first float portion includes a columnar first float body, and the second float portion has a cylindrical shape arranged so as to surround an outer peripheral portion of the first float portion. Can be configured.
Further, the first float portion includes the valve portion integrally, and also includes a substantially cylindrical first float main body, and the valve portion is configured by an upper valve body placed on the upper portion of the first float main body. Good.
Furthermore, as a preferred aspect of the present invention, the location of the float that supports the spring may be either the first float portion or the second float portion. When the first float portion having the valve portion is configured to support the spring, the load of the spring is directly received by the first float portion and is not applied to the second float portion. Therefore, the size of the tolerance dimension generated between the first float part and the second float part does not act so as to increase backlash to the valve part on the upper part of the first float part that receives the load of the spring. , Seal failure does not occur.

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.
A. First Embodiment (1) Schematic Configuration of Fuel Shutoff Valve 10 FIG. In FIG. 1, the surface of the fuel tank FT is formed of a composite resin material containing polyethylene, and a mounting hole FTb is formed in the tank upper wall FTa. A fuel shut-off valve 10 is attached to the tank upper wall FTa in a state where the lower part thereof enters the attachment hole FTb. The fuel shut-off valve 10 controls the outflow to the canister when the fuel in the fuel tank FT rises to a predetermined liquid level FL1 during refueling and functions an automatic stop.
The fuel cutoff valve 10 includes a casing 20, a float mechanism 50, and a spring 70 as main components. The casing 20 includes a casing main body 30, a bottom plate 35, and a lid body 40. A space surrounded by the casing main body 30 and the bottom plate 35 is a valve chamber 30S, and the valve chamber 30S is supported by a spring 70. The float mechanism 50 is accommodated.

(2) Configuration of Each Part of Fuel Shutoff Valve 10 FIG. 2 is an exploded 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 first communication hole 32 a that connects the inside of the fuel tank FT and the valve chamber 30 </ b> S is formed in the side wall portion 32, and an engagement hole 32 b for attaching the bottom plate 35 is formed. The bottom plate 35 is a member that closes the opening 30 a of the casing body 30, and the engagement claw 35 a formed on the outer peripheral portion of the bottom plate 35 engages with the engagement hole 32 b of the casing body 30, thereby opening the opening 30 a of the casing body 30. It is mounted to close. The bottom plate 35 is formed with a second communication hole 35b that allows communication between the valve chamber 30S and the fuel tank FT. Therefore, the inside of the fuel tank FT communicates with the valve chamber 30S through the second communication hole 35b.

  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, and these are integrally formed. . The tube part 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 a canister (not shown). Connected to. An inner welding end 43a that welds the upper end of the casing body 30 is formed at the lower part of the lid body 41, and an outer welding portion 43b that is welded to the tank upper wall FTa of the fuel tank FT is formed at the lower end of the flange 43. Is formed.

  The float mechanism 50 has a two-stage valve structure with improved restart valve characteristics, and includes a float 52 and an upper valve body 60 disposed on the float 52. The float 52 includes a first float portion 53 and a second float portion 57, which are assembled together. The first float unit 53 includes a first float body 54. The first float body 54 includes a large-diameter portion 54a and a small-diameter portion 54b extending below the large-diameter portion 54a, and these are integrally formed. A valve support portion 55 projects from the upper portion of the first float body 54. The valve support portion 55 is a portion that supports the upper valve body 60 so that the upper valve body 60 can swing. The valve support portion 55 includes a support protrusion 55 a that is a substantially conical protrusion (convex shape). An annular protrusion 55b for preventing 60 from being removed is formed. A stepped portion between the large-diameter portion 54 a and the small-diameter portion 54 b on the outer peripheral portion of the first float main body 54 serves as a spring support portion 53 a and supports the upper end of the spring 70. The spring 70 is disposed between the spring housing gap 53b (FIG. 1), which is a space between the large diameter portion 54a and the small diameter portion 54b, and spans the spring between the spring support portion 35c of the bottom plate 35. .

  The second float portion 57 has a cylindrical shape and includes a second float body 58 having a storage chamber 58a. Guide ridges 57b for guiding the float 52 in the vertical direction are provided on the outer peripheral portion of the second float portion 57, and the guide ridges 57b are provided at four locations on the side walls at equal intervals in the circumferential direction. It protrudes in a rib shape in the vertical direction.

FIG. 3 is an exploded perspective view showing the float 52. An assembling means for integrating the first float portion 53 and the second float portion 57 is provided. That is, a fitting portion 56 a is formed on the upper portion of the first float portion 53. The fitting portion 56a includes fitting protrusions 56b and fitting recesses 56c that are alternately arranged in the circumferential direction of the upper portion of the first float body 54. A positioning groove 56d is formed below each fitting projection 56b. In addition, positioning step portions 56e and 56f project from the outer peripheral portion of the large-diameter portion 54a and the bottom of the fitting recess 56c, respectively, and increase the positioning accuracy by hitting a part of the second float portion 57. ing.
On the other hand, the second float portion 57 is provided with a fitted hole 59a formed similar to the fitting portion 56a of the first float portion 53. The fitted hole 59a includes a fitting recess 59b that fits into the fitting protrusion 56b, and an arc upper wall that fits into the fitting recess 56c and restricts the second float portion 57 from moving upward. 59c. Further, an engaging claw 59d protrudes from the wall surface of the storage chamber 58a. The engaging claw 59d is inclined and projected toward the central axis so as to engage with the upper end of the positioning groove 56d of the first float portion 53.

  In order to assemble the first float portion 53 to the second float portion 57, the fitting portion 56 a is aligned with the fitting hole 59 a, and the first float portion 53 is inserted into the storage chamber 58 a of the second float portion 57. At this time, the outer surface of the fitting portion 56a pushes the engagement claw 59d to bend it. Then, the engaging claw 59d is engaged with the upper end of the positioning groove 56d by releasing the elastic force in the positioning groove 56d. In this state, the fitting portion 56a is fitted into the fitting hole 59a, that is, the fitting protrusion 56b is fitted into the fitting recess 59b, and the fitting recess 56c is fitted into the arc upper wall 59c. When the engaging claw 59d is prevented from being pulled out at the upper end of the positioning groove 56d, the first float portion 53 and the second float portion 57 are assembled together. In this state, a spring accommodation gap 53b for accommodating the spring 70 is formed between the first float portion 53 and the second float portion 57 (see FIG. 1).

  Returning to FIG. 2, the upper valve body 60 is a valve for opening and closing the connection passage 31 b and improving the restart valve characteristics, and is supported by the valve support portion 55 of the float 52 so that it can be raised and lowered and swingable. . FIG. 4 is an exploded perspective view showing the first valve portion 61 and the second valve portion 65 constituting the upper valve body 60, and FIG. 5 is an exploded sectional view of the upper valve body 60. The first valve unit 61 includes a substantially cylindrical first valve body 62 and a seat member 64. A support hole 62 a is formed in the first valve body 62 in the axial direction. An attachment portion 62 b for attaching the seat member 64 is formed on the upper portion of the first valve body 62. An annular recess 62c is formed on the outer peripheral portion of the first valve body 62, and four vent holes 62d for connecting the support hole 62a to the outside are formed in the annular recess 62c. As shown in FIG. 4, a slit 62e is formed in the lower portion of the first valve body 62, and an engaging piece 62g is formed elastically deformable from the fixed piece 62i by the slit 62e. An engagement hole 62h is formed in the engagement piece 62g.

  The sheet member 64 includes a first sheet portion 64a that is attached to and detached from the seal portion 31c, a connection hole 64b that is connected to the support hole 62a, a seal portion 64c that is formed at the lower end portion of the connection hole 64b, and an attachment portion 64d. And is integrally formed of a rubber material. The seat member 64 is attached to the attachment portion 62b of the first valve main body 62 by the attachment portion 64d, and the first seat portion 64a has a gap with respect to the upper surface of the first valve main body 62. When seated, it is elastically deformed to improve sealing performance.

In FIG. 5, the second valve portion 65 includes a cylindrical second valve main body 66. The second valve main body 66 is formed with a bottomed hole that opens downward, and a concave supported portion 66b is formed at the bottom center of the bottomed hole. The supported portion 66b is placed on the valve support portion 55 of the float 52, so that the second valve portion 65 is supported so as to be able to swing with the valve support portion 55 as a fulcrum.
Further, a second seat portion 66c is formed on the upper surface of the second valve body 66, and the second seat portion 66c is separated from the seal 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 engagement holes 62h of the first valve body 62, 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 hole 66e is formed in the upper part of each retaining claw 66d. By engaging with the annular protrusion 55b of the float 52, the second valve portion 65 is supported and can be moved up and down with respect to the float 52. It has been removed. A guide protrusion 66f for guiding the second valve portion 65 in the vertical direction is formed on the outer peripheral portion of the second valve body 66. The guide protrusions 66f are provided on the side wall of the second valve main body 66 at four equal intervals in the circumferential direction and in a rib shape in the vertical direction, and are slidable on the inner wall surface of the support hole 62a.
The center of gravity of the upper valve body 60 is set below the supported portion 66b. As a configuration for this purpose, the fixed piece 62i is formed to increase the weight of the lower part. Further, by making the valve support portion 55 convex and the supported portion 66b concave, the upper valve body 60 and the float 52 can be easily centered, and the center of gravity is set downward with respect to the fulcrum. Since it becomes easy, the attitude | position of the upper valve body 60 is also stabilized.

  FIG. 6 is an explanatory view for explaining the operation of the float mechanism 50. Assume that the float 52 is tilted in the direction of the arrow as shown in FIG. Since the supported portion 66b is supported at one point by the support protrusion 55a of the valve support portion 55 of the float 52, the second valve portion 65 is balanced like a seesaw, and the upper valve body 60 has a horizontal posture. maintain.

(3) Operation of the fuel cutoff valve 10 Next, the operation of the fuel cutoff valve 10 will be described. As shown in FIG. 1, when fuel is supplied into the fuel tank FT by refueling, the fuel vapor accumulated in the upper portion of the fuel tank FT as the fuel liquid level in the fuel tank FT rises is It enters the valve chamber 30S through the two communication holes 35b and the first communication hole 32a of the side wall 32, and escapes from the valve chamber 30S to the canister side through the connection passage 31b and the lid side passage 42a. As shown in FIG. 7, when the fuel liquid level in the fuel tank FT reaches the predetermined liquid level FL1, the fuel closes the first communication hole 32a, thereby increasing the tank internal pressure in the fuel tank FT. When the sensor detects the increase in the tank internal pressure, an auto-stop functioning to stop the fueling of the fueling gun is activated. In this state, the differential pressure between the tank internal pressure and the pressure in the valve chamber 30S increases, and the fuel level rises in the valve chamber 30S. When the fuel level in the valve chamber 30S reaches the height h0, the former becomes the latter by balancing 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. The float mechanism 50 rises as a unit, and the seat member 64 of the first valve portion 61 is seated on the seal portion 31c to close the connection passage 31b. As a result, when fuel is supplied to the fuel tank, it is possible to escape the fuel vapor from the fuel tank and to prevent the fuel from flowing out of the fuel tank.

  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 shown in FIG. As the float 52 descends, the float 52 pulls down the second valve portion 65 through the engagement between the retaining pawl 66 d of the second valve portion 65 and the annular protrusion 55 b of the float 52. Thereby, the 2nd sheet | seat part 66c leaves | separates from the seal | sticker 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. Since the retaining pawl 66d is engaged with the engagement hole 62h, the first valve portion 61 is also pulled down via the second valve portion 65. And when the 1st valve part 61 descends, the seat member 64 leaves | separates from the seal part 31c, and the connection channel | path 31b is opened.

Here, the reason why the restart valve characteristic can be improved in the fuel cutoff valve 10 will be described. In FIG. 8, the flow path area of the connection hole 64b of the upper valve body 60 is S1, the tank side pressure is P1, the canister side pressure is P0, the spring load is K, and the total weight of the float 152 and the upper valve body 60 is W. Then, when the value satisfies the following expression (1), the upper valve body 60 is opened from the closed state.
(P1-P0) S1 ≦ W−K (1)
The right side of the formula (1) is a positive value due to the difference between the weight W and the spring load K, that is, a force applied to the upper valve body 60 in the valve opening direction. The left side is a force applied in the valve closing direction so that the upper valve body 60 is attracted to the seal portion 31c. Here, when the flow path area S1 is small, the valve opens even with a large differential pressure (P1-P0). That is, if the canister side pressure P0 is constant, the valve opens even at a large tank side pressure P1. Therefore, the upper valve body 60 is opened with a small force by setting the flow passage area S1 of the connection hole 64b to be smaller than the flow passage area of the connection passage 31b. Thus, the two-stage valve structure by the upper valve body 60 functions to promote the improvement of the restart valve characteristic.

(4) Operation and effect of embodiment According to the present embodiment, the following operation and effect can be obtained.
(4) -1 The float 52 is composed of a plurality of members including the first float part 53 and the second float part 57, that is, the first float part 53 holding the upper valve body 60 is replaced with the second float part 57. And the buoyancy can be reliably increased by the capacity of the second float portion 57.
(4) -2 The first float portion 53 does not need to have a thick cup shape in order to increase buoyancy, and when formed by injection molding, the valve support portion 55 that supports the upper valve body 60 is formed. Sinking can be reduced and molding accuracy can be increased.
(4) -3 Since the float 52 can increase the buoyancy, the second float part 57 can be assembled integrally with the first float part 53 and the sealed storage chamber 58a can be eliminated. There is no fluctuation in the buoyancy of the float 52 due to the temperature change, and the fluctuation in the valve closing liquid level can be reduced.

(4) -4 When forming a space for housing the spring 70 inside the float 52 as in the prior art when forming the float 52 by resin injection molding, to make the space as small as possible Is preferably a cylindrical space that follows the outer shape of the spring 70 and is slightly larger. However, in order to form such a space, it is necessary to provide a narrow cylindrical mold, and to provide a cooling means having a thin cooling passage in order to cool the inside of the cylindrical shape quickly. Such a cooling means is difficult in terms of mold production. However, since the float 52 is formed of two members, the first float portion 53 and the second float portion 57, and the spring accommodating gap 53b is provided between them, such a mold is not required. That is, the first float part 53 may be formed with emphasis on the molding accuracy of the valve support part 55 and the like, and the arrangement of the cooling means is not limited by the shape. In addition, the second float portion 57 need only take into account the increase in buoyancy and the shape for disposing the spring 70, that is, the two members need not take a long time for cooling. Therefore, the injection molding cycle can be shortened and the productivity is excellent.
(4) -5 The space for arranging the spring 70 is not only simplified by providing the spring accommodating gap 53b between the first float part 53 and the second float part 57, but also as described above. It is not necessary to have a size that causes fluctuations in the buoyancy of the float 52 due to temperature changes. Further, even if the fuel goes up the spring storage gap 53b due to capillary action, the spring storage gap 53b is quickly discharged from the spring storage gap 53b. It does not cause fluctuations in valve fluid level.
(4) -6 The second float portion 57 includes a spring support portion 53 a that supports one end of the spring 70, so that the load of the spring 70 is directly received by the first float portion 53 and applied to the second float portion 57. Absent. Therefore, the size of the tolerance dimension generated between the first float portion 53 and the second float portion 57 increases the backlash to the upper valve body 60 supported by the first float portion 53 that receives the load of the spring 70. It does not act like this, and a seal defect does not occur.
(4) -7 Since the first float portion 53 and the second float portion 57 are integrated by the engaging means by the engagement of the engaging claw 59d and the positioning groove 56d, the first float portion 53 and the second float portion 57 are integrated. The assembly work of the part 57 can be simplified.

B. Second Embodiment FIG. 9 is a cross-sectional view showing a fuel cutoff valve 100 according to a second embodiment. This embodiment is an example applied to a so-called rollover valve that prevents fuel from flowing out of the fuel tank FT when the vehicle swings or tilts. The float mechanism 150 of the fuel cutoff valve 100 includes a float 152 and an upper valve body 160 disposed on the top of the float 152. The float 152 includes a first float portion 153 and a second float portion 157 that surrounds the outer periphery of the first float portion 153.
According to the fuel shut-off valve 100, when the fuel level in the fuel tank FT rises due to the inclination of the vehicle or the like, the float mechanism 150 rises and closes the connection passage 131b, so that the fuel flows out to the outside. To prevent.

  FIG. 10 is an enlarged cross-sectional view of the periphery of the upper valve body 160 of FIG. The upper valve body 160 is a valve for improving the restart valve characteristic, and is supported by the valve support portion 155 of the float 152 so as to be movable up and down and tiltable. The upper valve body 160 includes a donut-shaped valve body 161 and a seat member 162 attached to the valve body 161. A through hole 161 a is formed in the center of the valve body 161. The seat member 162 is formed of a rubber material that covers a wall surface of the through hole 161a and a part of the upper surface and the lower surface of the valve body 161, and has a first seat portion 162a that is attached to and detached from the first seal portion 131c and a conical portion at the lower portion. A second sheet portion 162b protruding in a shape and a connection hole 162c formed by covering the through hole 161a are provided.

  FIG. 11 is an explanatory view for explaining the operation of the upper valve body 160. Since the second seat portion 162b of the upper valve body 160 is formed in a substantially conical shape, the connection hole 162c is closed on the flat seal portion 156a. Even if the upper valve body 160 is inclined on the seal portion 156a, the inclination angle is regulated by the outer peripheral portion 161b of the valve main body 161 coming into contact with the step portion 157b, so that the sealing performance is not impaired. The upper valve body 160 is restricted from moving upward by the outer peripheral portion 161b engaging the engaging claw 157c, and receives a downward force as the float 152 is lowered.

C. Third Embodiment FIG. 12 is a cross-sectional view showing a fuel cutoff valve 100C according to a third embodiment. This embodiment is a modification of the second embodiment. That is, the float mechanism 150C is configured by assembling the first float part 153C and the second float part 157C, and further, the upper valve body 160C is integrally formed on the upper part of the first float part 153C. As described above, the upper valve body may be configured integrally with or separately from the first float.

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.
The fuel cutoff valve of the above-described embodiment has been described with respect to the configuration for mounting so as to block the mounting hole formed in the upper wall of the tank. Also good.

It is sectional drawing of the fuel cutoff valve concerning 1st Example of this invention. It is sectional drawing which decomposed | disassembled the fuel cutoff valve concerning 1st Example. It is the perspective view which fractured | ruptured the float partially and was decomposed | disassembled. It is a perspective view which decomposes | disassembles and shows the 1st valve part which comprises an upper valve body, and a 2nd valve part. It is sectional drawing which decomposed | disassembled the upper 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 operation | movement following FIG. It is sectional drawing which shows the fuel cutoff valve concerning 2nd Example. FIG. 10 is an enlarged cross-sectional view of the periphery of the upper valve body in FIG. 9. It is explanatory drawing explaining an effect | action of an upper valve body. It is sectional drawing which shows the fuel cutoff valve concerning 3rd Example.

Explanation of symbols

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 ... Seal part 32 ... Side wall part 32a ... first communication hole 32b ... engagement hole 35 ... bottom plate 35a ... engagement claw 35b ... second communication hole 35c .. Spring support part 40 ... Lid body 41 ... Lid body 42 ... Tube part 42a ... Lid side passage 43 ... Flange 43a ... Internal weld end 43b ... Outer weld part 50 ... Float mechanism 52 ... Float 53 ... First float part 53a ... Spring support part 53b ... Spring storage gap 54 ... First float body 54a ... Large diameter part 54b .. .Small diameter part 55 ... valve support part 55a ... supporting protrusion 55b ... annular protrusion 56e, 56f ... positioning step part 56a ... fitting part 56b ... fitting protrusion 56c. ..Matching recess 56d ... Positioning 57 ... Second float portion 57b ... Guide protrusion 58 ... Second float main body 58a ... Storage chamber 59a ... Fitted hole 59b ... Fitting recess 59c ... Arc Upper wall 59d ... engaging claw 60 ... upper valve body 61 ... first valve portion 62 ... first valve body 62a ... support hole 62b ... mounting portion 62c ... annular recess Location 62d ... Vent hole 62e ... Slit 62g ... engagement piece 62h ... engagement hole 62i ... fixing piece 64 ... sheet member 64a ... first sheet portion 64b ... Connection hole 64c ... Seal part 64d ... Mounting part 65 ... Second valve part 66 ... Second valve body 66b ... Supported part 66c ... Second sheet part 66d ... Prevention Claw 66e ... engagement hole 66f ... guide protrusion 70 ... spring 100 ... fuel shutoff valve 100C ... fuel shutoff valve 131b ... connection passage 131c ... first seal part 150. ..Float mechanism 150C ... Float mechanism 152 ... Float 153 ... first float part 153C ... first float part 155 ... valve support part 156a ... seal part 157 ... second float part 157C ... second float part 157b ... stage 157c ... engagement claw 160 ... upper valve body 160C ... upper valve body 161 ... valve body 161a ... through hole 161b ... outer peripheral part 162 ... sheet member 162a ... 1st sheet part 162b ... 2nd sheet part 162c ... Connection hole FT ... Fuel tank FL1 ... Predetermined liquid level FTa ... Tank upper wall FTb ... Mounting hole

Claims (6)

In a fuel cutoff valve mounted on the upper part of the fuel tank (FT), which opens and closes a connection passage (31b) that connects the inside of the fuel tank (FT) and the outside to cut off the communication between the fuel tank (FT) and the outside.
A casing (20) forming a valve chamber (30S) communicating the fuel tank (FT) and the connection passage (31b);
A float (52) housed in the valve chamber (30S), which opens and closes the connection passage (31b) by raising and lowering the buoyancy according to the fuel level in the valve chamber (30S);
A spring (70) for biasing the float (52) in the valve closing direction;
With
The float (52)
A first float part (53) having a valve part for opening and closing the connection passage (31b);
It is formed so as to surround the outer periphery of the first float part (53), is integrated with the first float part (53), and moves up and down between the first float part (53) and the first float part (53). A second float portion (57) that forms a spring storage gap (54e) along and along which the spring (70) is stored;
A fuel cutoff valve characterized by comprising: The fuel cutoff valve according to claim 1,
The said 1st float part (53) and the said 2nd float part (55) are fuel cutoff valves integrated by the engaging means by an engaging claw and an engaging hole. The fuel cutoff valve according to claim 1 or 2,
The spring storage gap (54e) is a fuel cutoff valve connected to the outside of the float (52). The fuel cutoff valve according to any one of claims 1 to 3,
The first float portion (153) includes a columnar first float body (154), and the second float portion (157) is disposed so as to surround an outer peripheral portion of the first float portion (153). A fuel cut-off valve that has a cylindrical shape. The fuel cutoff valve according to any one of claims 1 to 4,
The first float portion includes a substantially cylindrical first float main body, and a fuel cutoff valve in which the valve portion is configured by an upper valve body placed on the upper portion of the first float main body. The fuel cutoff valve according to claim 1,
The first float part is a fuel cutoff valve provided with a spring support part for supporting the spring.

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