JP2009227032A - Fuel shut-off valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the reliability of opening and closing accompanying the up and down movement of a float in a connection path connecting a fuel tank to the outside. <P>SOLUTION: The float 40 bringing the connection path 26 connecting to the outside opening and closing is configured to store an inner float 70 in a storage chamber 52 of an outer float 50. The outer float 50 has a projection 54 at its inside. The inner float 70 has a spring storage chamber 72 of a spring S at its lower end side, and a recessed slit 78 from which the projection 54 enters is formed to reach the spring storage chamber 72. Thereby, the projection 54 of the outer float 50 enters the inside of the spring storage chamber 72 of the inner float 70 side and interferes the spring storage chamber 72. Thus, the spring S directly applies energization force via the projection 54 to the outer float 50 having a seal member 56 concerned with the opening and closing of the connection path 26. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel cutoff valve that cuts off a communication between a fuel tank and the outside.

  This type of fuel shut-off valve is mounted on the upper part of the fuel tank, and is provided with a float in a casing valve chamber so that it can float and sink, and has a connection passage connecting the fuel tank and the outside (canister). The door is opened and closed. That is, the float receives a buoyancy that increases or decreases depending on the fuel liquid level in the valve chamber of the casing. Therefore, the float rises in the valve chamber by receiving this buoyancy and closes the connection passage at the valve portion that the float has. Thus, the fuel shut-off valve prevents the fuel from flowing out.

  In general, such a fuel shut-off valve has its casing and float, which are constituent materials, made of a resin molded product. Therefore, in order to improve float shape accuracy or productivity, the float should be a two-piece part of an outer float and an inner float. (For example, Patent Document 1).

JP 2007-30806 A

  In the above-mentioned patent documents, there are proposed a mode in which the urging force of the float for assisting the rise of the float is received by the inner float and a mode in which the float is received by the outer float. In the aspect in which the spring biasing force is received by the outer float, the biasing force is directly exerted on the outer float having the valve portion, so that the reliability of opening and closing of the connection passage by the valve portion is increased. However, since the outer float is provided with a recessed hole for accommodating the inner float, the spring is accommodated in the gap between the outer float and the inner float, and the spring is received by the recessed hole step portion of the outer float. It has been pointed out.

  In a vehicle equipped with a fuel cutoff valve, the fuel cutoff valve is vibrated or tilted in accordance with acceleration / deceleration, traveling on a curve or traveling on a rough road. When the spring is displaced in the gap as described above due to such vibration or inclination, the spring may be detached from the depression hole step portion described above. If the spring is removed from the depression hole step portion in this way, the spring bites into the depression hole or the spring contact becomes uneven, so the outer float is tilted by the urging force of the spring, and the valve portion when the float rises The reliability of opening and closing the connection passage due to is reduced. Such a situation can be avoided by widening the above-mentioned gap for accommodating the spring and widening the recessed hole step, but this gap does not act to receive buoyancy from the fuel. Can not be wide. Therefore, it may not be possible to avoid a situation in which the spring is detached from the depression hole step described above, and an improvement in the reliability of opening and closing of the connection passage accompanying the floating of the float has been required.

  In view of the above-described problems, an object of the present invention is to improve the reliability of opening and closing of a connection passage that accompanies the float.

  In order to achieve at least a part of the above object, the present invention adopts the following configuration.

[Application: Fuel shut-off valve]
A fuel shut-off valve that is mounted on the upper part of the fuel tank and that opens and closes a connection passage that connects the fuel tank and the outside to cut off the communication between the fuel tank and the outside.
A casing forming a valve chamber communicating the fuel tank and the connection passage;
A float that is contained in the valve chamber and has a valve portion that floats and sinks in response to a buoyancy that increases or decreases depending on a fuel liquid level in the valve chamber, and opens and closes the connection passage;
A spring for biasing the float in the valve closing direction;
A bottom lid that is installed at the lower end of the casing and supports the spring on the lower end side;
The float is
A cup-shaped outer float comprising the valve portion for opening and closing the connection passage, a storage chamber opened downward, and a protruding piece protruding from the ceiling wall of the storage chamber toward the lower end;
An annular spring accommodating chamber that is accommodated in the accommodating chamber and is integrated with the outer float, encloses and accommodates the spring with inner and outer peripheral walls inside and outside the spring, and the projecting piece of the outer float extends from the ceiling wall of the spring accommodating chamber. An inner float having a protruding piece insertion recess formed on the ceiling side of the spring accommodating chamber so as to enter the inside of the spring accommodating chamber;
The gist of the invention is that the spring housed in the spring housing chamber of the inner float exerts the urging force on the lower end of the protruding piece of the outer float.

  In the fuel cutoff valve configured as described above, when the fuel is supplied to the fuel tank using the fuel cutoff valve 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. When the float rises, the spring also exerts a biasing force on the float, so that the float rises quickly and the response of closing the connection passage is enhanced. On the other hand, when the fuel level in the valve chamber is lowered, the buoyancy acting on the float is reduced. However, since the urging force of the spring acts on the float, the drop of the float is delayed with respect to the drop in the liquid level. As a result, the release of the connection passage occurs after the fuel level is sufficiently lowered, so that inadvertent outflow of fuel can be prevented.

  The float is composed of a plurality of members including an outer float and an inner float. The inner float is housed in the outer float housing chamber and is integrated into a float that opens and closes the connection passage as described above. When the inner float is housed in the outer float housing chamber, the protruding piece of the outer float enters the projecting piece insertion recess of the inner float from the ceiling wall side of the spring housing chamber to the inside of the spring housing chamber of the inner float. Reach. Thereby, the protrusion piece of an outer float makes the lower end interfere with the inner-periphery wall of the said storage chamber in the inside of a spring storage chamber. In addition, the spring accommodated in the annular spring accommodating chamber exerts a biasing force on the lower end of the protruding piece of the outer float. Therefore, the urging force of the spring can be directly applied to the outer float having the valve portion, so that the reliability of opening and closing of the connection passage by the valve portion can be improved. Moreover, since the spring accommodating chamber is annular, the buoyancy acting according to the fuel liquid level can be prevented from being inadvertently reduced. In addition, since the spring is housed in the spring housing chamber of the inner float and is surrounded by the inner and outer peripheral walls, the inclination of the spring is limited by the inner and outer peripheral walls. Even if the spring is tilted, the tilted spring interferes with the inner and outer peripheral walls of the spring accommodating chamber and reliably exerts an urging force on the lower end of the protruding piece of the outer float that has entered the accommodating chamber. As a result, according to the fuel cutoff valve having the above-described configuration, the connection passage can be opened and closed with the rise and fall of the float with high reliability.

  The fuel shut-off valve described above can be configured as follows. For example, a plurality of protruding pieces of the outer float are provided on the ceiling wall of the storage chamber at equal pitches on the circumference, and the protruding pieces insertion recesses of the inner float are arranged on the ceiling wall of the spring storage chamber in accordance with the plurality of protruding pieces. It is possible to provide a plurality at equal circumferential pitches. In this way, the urging force of the spring extends from the lower end of the projecting piece with the same pitch on the circumference to the outer float, so that the urging force and the direction are almost equally divided on the circumference. Tilt can be suppressed.

  The protruding piece may be formed in a rib shape extending in the center direction of the storage chamber and hanging from the ceiling wall to the inner peripheral wall of the storage chamber. In this way, the outer float can be reinforced with the protruding piece, so that the thickness can be reduced.

  In these cases, the inner float can be formed of a material having a specific gravity smaller than that of the outer float. By doing so, the force obtained by subtracting the weight of the inner float from the resultant force of the buoyancy acting on the float and the urging force of the spring increases, so that the float rises quickly and the connection passage can be quickly closed. In addition, the release of the connection passage due to the biasing force of the spring when the fuel level is lowered is also delayed, which is desirable from the viewpoint of avoiding the outflow of the fuel itself.

  In general, light specific gravity resin material swells to gasoline, which is a vehicle fuel, and therefore, if the upper end of the spring is received by the ceiling wall of the spring accommodation chamber of the inner float, the connection passage opening / closing position of the casing to the upper end of the spring And the distance from the connecting passage to the valve portion that closes it varies depending on the difference in the degree of swelling between the casing and the inner float. However, in the fuel cutoff valve of the above aspect, since the upper end of the spring is received by the lower end of the protruding piece of the outer float, if the outer float is made of the same material as the casing, the distance from the connection passage opening / closing position of the casing to the upper end of the spring The distance from the connecting passage to the valve portion that closes it can be maintained. Therefore, the reproducibility and reliability of opening and closing of the connection passage accompanying the float ups and downs are increased.

  Hereinafter, embodiments of the present invention will be described based on examples. FIG. 1 is an explanatory view schematically showing an entire structure of a fuel cutoff valve 10 as an embodiment of the present invention. FIG. 2 is a sectional view of the fuel cutoff valve 10 in an assembled state taken along line 2-2 in FIG. 3 is an enlarged explanatory view showing a part of the main part of the fuel cutoff valve 10, and FIG. 4 is a sectional view showing the fuel cutoff valve 10 taken along line 4-4 in FIG. 5 is a cross-sectional view of the fuel cutoff valve 10 taken along the line 5-5 in FIG.

  As shown in the figure, the fuel cutoff valve 10 is mounted on the upper portion of the fuel tank FT. The surface of the fuel tank FT is formed of a composite resin material containing polyethylene, and the mounting hole FTb of the tank upper wall FTa is used as a mounting hole for the fuel cutoff valve 10. When the fuel cutoff valve 10 is mounted in the mounting hole FTb, the lower end portion 21 of the upper lid 20 is thermally welded to the tank upper wall FTa, and a casing 30 described later is positioned inside the fuel tank FT. The fuel cutoff valve 10 regulates the flow of fuel in the fuel tank FT to the canister when the vehicle is tilted or swings.

  The fuel shut-off valve 10 includes an upper lid 20 located outside the tank, a casing 30, a float 40, a spring S, and a bottom lid 90. The casing 30 is fitted and fixed to the lower end of the upper lid 20, and the casing A bottom lid 90 is attached to the lower end of 30. In the present embodiment, the above-described components excluding the spring S are provided as a resin molded product.

  The upper lid 20 is provided with a connecting pipe portion 22 of a pipe from a canister (not shown) protruding sideways, and a portion from the inside of the connecting pipe portion 22 to below the upper lid 20 is defined as a lid-side passage 24. The lid side passage 24 communicates with a valve chamber 33 of a casing 30 described later via a connection passage 26 at a substantially central position of the upper lid 20. Therefore, the connection passage 26 connects the fuel tank FT, specifically, the tank interior and an external canister.

  The casing 30 is a cylindrical body whose lower end is released, and has a connection passage 26 in the center of the casing ceiling wall 31, and the lower end edge of the passage is an annularly raised lip portion 32, and the space below the casing ceiling wall 31. Is a valve chamber 33. The valve chamber 33 communicates the inside of the fuel tank FT and the connection passage 26. In addition, the casing 30 is provided with a small-diameter vent 34 in the peripheral wall on the ceiling wall side, and is provided with four engagement windows 35 at equal pitches into which the mounting claws of the bottom lid 90 enter at the lower end side of the peripheral wall. Moreover, the lower end of the peripheral wall of the casing 30 is hung between adjacent engagement windows 35 to form a thick portion 36 for reinforcement when the bottom lid 90 is fitted.

  The float 40 is accommodated in the valve chamber 33 of the casing 30, and floats and sinks by receiving buoyancy that increases and decreases depending on the fuel liquid level in the valve chamber, and opens and closes the connection passage 26 described above. The float 40 includes an outer float 50 and an inner float 70, and the inner float 70 is accommodated in the outer float 50. The outer float 50 includes a bottomed cup-shaped main body 51 whose opening side faces downward, a storage chamber 52 that opens downward, and a protruding piece 54 that protrudes from the ceiling wall 53 of the storage chamber 52 toward the lower end, A seal mounting seat 55 protruding above the ceiling wall 53 and a rubber seal member 56 are provided. The projecting piece 54 extends in the center direction of the storage chamber 52 and has a rib shape extending from the ceiling wall 53 to the inner peripheral wall of the storage chamber 52 (that is, the inner peripheral wall of the main body 51). Are formed at four locations at equal circumferential pitches.

  As shown in FIG. 3, the seal mounting seat 55 is formed with a depressed center, so that the seal member 56 mounted on the seal mounting seat 55 can be bent and deformed at the center. Therefore, when the outer float 50 is raised as will be described later, the seal member 56 bends and deforms when it presses against the lip portion 32 around the connection passage 26, thereby more reliably closing the connection passage 26. Further, since the seal member 56 moves away from the lip portion 32 by releasing the outer float 50 and releases the connection passage 26, it functions as a valve portion that opens and closes the connection passage 26. Since the notch 55a is formed in the seal mounting seat 55, the air below the seal member 56 escapes from the notch 55a, so that the seal member 56 bends and deforms without hindrance.

  In addition, the outer float 50 includes a plurality of protrusions 57 around the outer peripheral wall of the main body 51, and includes two engagement windows 58 at equal pitches into which the engagement claws of the inner float 70 enter the lower end side of the main body 51. . The protrusion 57 on the outer peripheral wall of the main body 51 functions as a guide when the outer float 50 floats and sinks in the valve chamber 33 of the casing 30.

  The inner float 70 has a cylindrical shape with a through hole 71 at the center, and includes a spring accommodating chamber 72 around the through hole 71. The spring accommodating chamber 72 is formed in an annular shape and is surrounded by the outer peripheral wall 74 and the inner peripheral wall 76 to accommodate the spring S. The inner float 70 has two engaging claws 77 at an equal pitch on the outer peripheral wall of the lower end thereof. The inner float 70 is accommodated in the accommodating chamber 52 of the outer float 50, and the engaging claws 77 are engaged with the engaging window 58 of the outer float 50. By combining, the outer float 50 is integrated.

  Further, as shown in FIG. 1, the inner float 70 includes a concave slit 78 formed from the float top surface side to the lower side. The concave slits 78 are formed at four locations on the top surface of the float at an equal circumferential pitch, and this formation pitch is the same as the pitch of the protruding pieces 54 in the outer float 50. The concave slit 78 is wider than the protruding piece 54 and is formed with a depth closer to the center than the center side end surface 54S of the protruding piece 54. Further, the concave slit 78 is formed from the top surface of the float to a position lower than the ceiling wall of the spring accommodating chamber 72 as shown in FIG. For this reason, when the inner float 70 is accommodated in the accommodating chamber 52 of the outer float 50, the protruding pieces 54 of the outer float 50 enter the respective concave slits 78 of the inner float 70 from the float top surface side, and the spring accommodating chamber. It reaches to the inside of 72. Therefore, the lower end surface 54 </ b> D of the protruding piece 54 is positioned at a position lower than the ceiling wall of the spring accommodating chamber 72 and faces the open end of the spring accommodating chamber 72 cut out by the concave slit 78. Since the spring S is accommodated in the spring accommodating chamber 72 when the bottom cover 90 described later is mounted, the spring S comes into contact with the lower end surface 54D of each protruding piece 54 of the outer float 50 and is closed to the float 40. The urging force in the direction is directly applied to the protruding piece 54 from the lower end side.

  The relationship between the protruding piece 54 and the concave slit 78 and the relationship including the spring accommodating chamber 72 will be described in cross section. As shown in FIG. 4 which is a sectional view above the ceiling wall of the spring accommodating chamber 72, Each protruding piece 54 enters each concave slit 78 of the inner float 70. As shown in FIG. 5, which is a sectional view below the ceiling wall of the spring accommodating chamber 72, each concave slit 78 is formed closer to the center than the inner peripheral wall 76 of the spring accommodating chamber 72. Each projecting piece 54 that has entered the concave slit 78 interferes with the annular spring accommodating chamber 72 with its center side end face 54S positioned closer to the center than the inner peripheral wall 76 of the spring accommodating chamber 72. Become. That is, the spring S directly exerts its urging force on the protruding piece 54 at a location where it interferes with the spring accommodating chamber 72.

  The bottom cover 90 includes four engagement claws 92 at an outer peripheral edge at an equal circumferential pitch, and is fitted to the lower end of the casing 30 with the engagement claws engaged with the engagement windows 35 of the casing 30. . Accordingly, the lower end of the valve chamber 33 of the casing 30 is closed, and the lower end of the float / sink region of the float 40 is determined by the bottom lid 90. Further, the bottom lid 90 has a bottom through its center through hole 94, a plurality of small-diameter through holes 96 around it, and a base of the engaging claw 92 in order to allow fuel to flow into and out of the valve chamber 33. The spring seat 99 is provided with a hole 98 and is raised around the central through hole 94.

  In order to obtain the fuel cutoff valve 10 from the above components, first, the inner float 70 is accommodated in the outer float 50 and the floats are integrated to form the float 40. Next, after the float 40 is accommodated in the valve chamber 33 of the casing 30 to which the upper lid 20 has been attached, the spring S is accommodated in the spring accommodating chamber 72 of the inner float 70 and the bottom lid 90 is attached to the lower end of the casing 30. In the fuel cutoff valve 10 thus obtained, the spring S is supported at the lower end side by the spring seat 99 of the bottom cover 90 and always exerts its urging force directly on the outer float 50 via the protruding piece 54.

  As described above, in the fuel cutoff valve 10 of this embodiment, when fuel is supplied to the fuel tank FT and the fuel level reaches a predetermined level, the central through hole of the bottom cover 90 is formed inside the valve chamber 33. The float 40 is lifted by buoyancy due to the fuel flowing in from the through holes 94 and the like. As the float 40 rises, the seal member 56 on the top contacts the lip portion 32 around the connection passage 26. As a result, the connection passage 26 is closed, so the fuel cutoff valve 10 shuts off the fuel tank FT from the outside (canister) and prevents fuel from flowing out of the fuel tank FT to the outside. When the float rises, the spring S also exerts a biasing force on the float 40, so that the float 40 rises quickly and can close the connection passage 26 with high responsiveness. In addition, in this embodiment, since the seal member 56 is mounted on the seal mounting seat 55 of the outer float 50 so as to be able to bend and deform, the connection passage 26 can be closed with high reliability by the seal member 56.

  When the fuel consumption progresses and the fuel flows out from the valve chamber 33 and the fuel level is lowered, the buoyancy acting on the float 40 is reduced by the amount of the lowered liquid level. Since the urging force of the spring S is constantly acting on the float 40 as described above, the lowering of the float 40 is delayed with respect to the lowering of the fuel level. As a result, the release of the connection passage 26 occurs after the fuel level is sufficiently lowered, so that inadvertent fuel outflow from the fuel tank FT can be prevented. After the connection passage 26 is released, the fuel vapor is supplied to the connection passage 26. 26 to an external canister.

  The float 40 that opens and closes the connection passage 26 described above is configured by accommodating the inner float 70 in the accommodating chamber 52 of the outer float 50, and the protruding piece 54 of the outer float 50 is located on the side of the inner float 70 as described above. The inside of the spring housing chamber 72 interferes with the spring housing chamber 72, specifically the outer peripheral wall 74 and the inner peripheral wall 76 surrounding the spring S. Therefore, the spring S directly exerts a biasing force on the outer float 50 having the seal member 56 involved in opening / closing of the connection passage 26 via the protruding piece 54, so that the connection passage 26 is opened / closed by the seal member 56 of the outer float 50. Can be performed with high reliability. Moreover, since the spring accommodating chamber 72 that accommodates the spring S is annular, the buoyancy according to the fuel liquid level can be received at a portion closer to the center than the spring accommodating chamber 72, so that the buoyancy is not inadvertently reduced. You can In addition, since the spring S is accommodated in the spring accommodating chamber 72 of the inner float 70 and is surrounded by the outer peripheral wall 74 and the inner peripheral wall 76, the inclination of the spring S is limited by the inner and outer peripheral walls. Even if the spring S is inclined, the inclined spring S interferes with the inner and outer peripheral walls of the spring accommodating chamber 72 as described above, and the protruding piece 54 of the outer float 50 that has entered the spring accommodating chamber 72 enters the spring accommodating chamber 72. Ensuring that the lower end is energized. As a result, according to the fuel cutoff valve 10 of the present embodiment, the reliability of opening and closing of the connection passage 26 accompanying the float 40 sinking can be improved.

  Further, in the fuel cutoff valve 10 of the present embodiment, the protruding pieces 54 of the outer float 50 are provided at four positions on the ceiling wall 53 of the storage chamber 52 at equal circumferential intervals, and the concave slits 78 of the inner float 70 also protrude. Matching with the piece 54, it provided with the equal pitch on the circumference. Therefore, the spring S exerts its urging force equally on the outer float 50 from the lower end of the circumferentially equal pitch projecting piece 54 to the outer float 50 on the circumference. It is possible to suppress the hindrance of float floating and sinking due to the float inclination with high effectiveness. This contributes to an improvement in the reliability of opening and closing of the connection passage 26 accompanying the float 40 sinking.

  In addition, in this embodiment, as shown in FIG. 2, the protruding piece 54 is formed in a rib shape extending in the center direction of the storage chamber 52 and hanging from the ceiling wall 53 of the storage chamber 52 to the inner peripheral wall of the main body 51. did. Therefore, since the outer float 50 can be reinforced by the protruding piece 54, the outer float 50 can be thinned.

  Further, in this embodiment, when the constituent materials such as the casing 30 excluding the spring S, the outer float 50, the inner float 70, etc. are made into resin molded products, the casing 30 and the outer float 50 are polyacetal having a small degree of swelling with respect to gasoline. The inner float 70 was formed using a polyamide resin (PA12) having a lighter specific gravity than POM, although the degree of swelling with respect to gasoline was larger than that of POM. Therefore, since the force obtained by subtracting the weight of the inner float 70 from the resultant force of the buoyancy acting on the float 40 and the urging force of the spring S increases, the float 40 can be quickly raised and the connection passage 26 can be quickly closed. That is, the connection passage 26 is closed with high responsiveness according to the fuel liquid level, so that the outflow of fuel can be avoided quickly. Even when the fuel level is lowered, the release of the connection passage 26 by the urging force of the spring S can be further delayed, which is desirable from the viewpoint of avoiding the outflow of the fuel itself.

  In the fuel cutoff valve 10 of the present embodiment, the spring urging force is exerted on the outer float 50 having the seal member 56 via the lower end of the protruding piece 54, so the distance between the upper surface of the seal member 56 and the lower end surface 54D. VL is constant. Moreover, since the outer float 50 and the casing 30 are formed by the same POM, the outer float 50 and the casing 30 made of the same material cause the same degree of swelling when immersed in fuel. As a result, even if the inner float 70 swells greatly as the fuel is immersed, the distance VL and the distance from the upper surface of the seal member 56 to the distance 26 are maintained without being affected by this. Therefore, the reproducibility and reliability of opening and closing of the connection passage 26 associated with the floating and sinking of the float 40 in which the outer float 50 and the lighter specific gravity inner float 70 are integrated can be improved.

  Next, a fuel cutoff valve 10A according to another embodiment will be described. In this fuel cutoff valve 10A, the protruding piece 54 in the outer float 50 is different from the concave slit 78 formed in the inner float 70 in conformity therewith. FIG. 6 is an equivalent view of FIG. 1 and is an explanatory view schematically showing the entire structure of the fuel cutoff valve 10A of another embodiment. FIG. 7 is a view equivalent to FIG. 4 and shows the fuel cutoff valve 10A in the spring accommodating chamber. FIG. 8 is a cross-sectional view as viewed from above the ceiling wall, and FIG. 8 is a view corresponding to FIG. 5 and is a cross-sectional view as viewed from below the ceiling wall of the spring accommodating chamber.

  In this fuel shut-off valve 10A, the top cover 20, casing 30 and bottom cover 90 are the same as the fuel shut-off valve 10 described above, and the outer float 50A is the same in appearance but has a different protruding piece 54A inside, The inner float 70A is the same for the internal spring accommodating chamber 72 but is different in the concave slit 78A. That is, as shown in FIGS. 7 and 8, the outer float 50 </ b> A includes, in the main body 51, two protruding pieces 54 </ b> A that protrude from the ceiling wall 53 in a bridge shape. Even in the protruding piece 54A, it is formed so as to enter the inside of the spring accommodating chamber 72 of the inner float 70A, and each protruding piece 54A interferes with the spring accommodating chamber 72 as shown in FIG. On the other hand, as shown in FIG. 6, the inner float 70 </ b> A is notched and provided with a double-recessed concave slit 78 </ b> A into which the protruding piece 54 </ b> A of the outer float 50 </ b> A enters. The concave slit 78A is formed wider than the width of the projecting piece 54A, and has a depth reaching the spring accommodating chamber 72 from the float ceiling wall.

  Even in the above-described fuel cutoff valve 10A, the spring S accommodated in the spring accommodating chamber 72 of the inner float 70 has its urging force applied to the outer portion at the interference position between the spring accommodating chamber 72 and the concave slit 78A shown in FIG. It directly affects the float 50A through the protruding piece 54A. Therefore, the above-described effects can be achieved also by the fuel cutoff valve 10A.

  As mentioned above, although the embodiment of the present invention has been described in the embodiments, the present invention is not limited to the above-described embodiments and modifications, and can be implemented in various modes without departing from the gist thereof. Is possible.

It is explanatory drawing which decomposes | disassembles and shows roughly the whole structure of the fuel cutoff valve 10 as an Example of this invention. FIG. 2 is a cross-sectional end view showing the fuel cut-off valve 10 in the assembled state, taken along line 2-2 in FIG. FIG. 3 is an explanatory view showing an enlarged part of a main part of the fuel cutoff valve 10. FIG. 4 is a cross-sectional view of the fuel cutoff valve 10 taken along line 4-4 in FIG. FIG. 5 is a sectional view of the fuel cutoff valve 10 taken along line 5-5 in FIG. FIG. 2 is an explanatory view schematically showing the entire configuration of a fuel cutoff valve 10A of another embodiment, corresponding to FIG. FIG. 5 is a cross-sectional view of the fuel cutoff valve 10 </ b> A viewed from above the ceiling wall of the spring housing chamber, corresponding to FIG. 4. FIG. 6 is a cross-sectional view of the fuel cutoff valve 10 </ b> A viewed from below the ceiling wall of the spring housing chamber, corresponding to FIG. 5.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 10A ... Fuel cutoff valve 20 ... Upper lid 21 ... Lower end part 22 ... Connection pipe part 24 ... Cover side passage 26 ... Connection passage 30 ... Casing 31 ... Casing ceiling wall 32 ... Lip part 33 ... Valve chamber 34 ... Vent 35 ... Engagement window 36 ... Thick part 40 ... Float 50, 50A ... Outer float 51 ... Main body 52 ... Storage chamber 53 ... Ceiling wall 54, 54A ... Projection piece 54D ... Lower end surface 54S ... Center side end surface 55 ... Seal mounting seat 55a ... Notch 56 ... Seal member 57 ... Projection strip 58 ... Engagement window 70, 70A ... Inner float 71 ... Through hole 72 ... Spring accommodating chamber 74 ... Outer peripheral wall 76 ... Inner peripheral wall 77 ... Engaging claw 78, 78A ... Concave slit 90 ... Bottom cover 92 ... engaging claw 94 ... central through hole 96 ... through hole 98 ... through hole 99 ... spring seat S ... spring FT ... fuel tank FTa ... tongue The upper wall FTb ... mounting holes

Claims (4)

A fuel shut-off valve that is mounted on the upper part of the fuel tank and that opens and closes a connection passage that connects the fuel tank and the outside to cut off the communication between the fuel tank and the outside.
A casing forming a valve chamber communicating the fuel tank and the connection passage;
A float that is contained in the valve chamber and has a valve portion that floats and sinks in response to a buoyancy that increases or decreases depending on a fuel liquid level in the valve chamber, and opens and closes the connection passage;
A spring for biasing the float in the valve closing direction;
A bottom lid that is installed at the lower end of the casing and supports the spring on the lower end side;
The float is
A cup-shaped outer float comprising the valve portion for opening and closing the connection passage, a storage chamber opened downward, and a protruding piece protruding from the ceiling wall of the storage chamber toward the lower end;
An annular spring accommodating chamber that is accommodated in the accommodating chamber and is integrated with the outer float, encloses and accommodates the spring with inner and outer peripheral walls inside and outside the spring, and the projecting piece of the outer float extends from the ceiling wall of the spring accommodating chamber. An inner float having a protruding piece insertion recess formed on the ceiling side of the spring accommodating chamber so as to enter the inside of the spring accommodating chamber;
The fuel cutoff valve, wherein the spring accommodated in the spring accommodation chamber of the inner float exerts the urging force on a lower end of the protruding piece of the outer float. The fuel cutoff valve according to claim 1,
The outer float comprises a plurality of the protruding pieces at equal circumferential pitches on the ceiling wall of the storage chamber,
The inner float is provided with a plurality of protruding piece insertion recesses at equal circumferential pitches on the ceiling wall of the spring accommodating chamber in accordance with the plurality of protruding pieces.   3. The fuel cutoff valve according to claim 1, wherein the protruding piece extends in a center direction of the storage chamber and is formed in a rib shape from the ceiling wall to the inner peripheral wall of the storage chamber.   The fuel cutoff valve according to any one of claims 1 to 3, wherein the inner float is formed of a material having a specific gravity smaller than that of the outer float.

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