JP2007253837A - Fuel shut-off valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel shut-off valve 10 smoothly filling up a fuel tank without lifting even when a high lift on a first valve mechanism 50 is generated in refueling. <P>SOLUTION: The fuel shut-off valve 10 has a first valve chest 31S and a second valve chest 35S in a casing 20, and stores a first valve mechanism 50 and a second valve mechanism 60 in each valve chest. A first float 51 of the first valve mechanism 50 is elevated when the fuel level reaches the first liquid level FL1, and closes a first connection passage 32a. The second valve mechanism 60 is elevated when the first float reaches the second liquid level FL2 higher than the first liquid level FL1, and closes a second connection passage 36a. An inter-valve passage 32c is provided between the first valve chest 31S and the second valve chest 35S so as to increase the internal pressure in a fuel tank FT when the first float 51 closes the first connection passage 32a. The first float 51 has an inclined face 52c on the entire lower circumference obliquely from a seat face 52a of the first float 51 so that the posture of the float is stable even by the gas flow during the refueling. <P>COPYRIGHT: (C)2008,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.

  2. Description of the Related Art Conventionally, as this type of fuel cutoff valve, a two-stage full tank regulating valve having a function of preventing blow-back from a fuel filler port and supercharging is known (Patent Documents 1 and 2). In these technologies, a lower valve chamber, an intermediate valve chamber, and an upper valve chamber are arranged in a casing from the lower side to the upper side, a lower float is accommodated in the lower valve chamber, and an upper float is accommodated in the upper valve chamber, By raising and lowering the lower float and the upper float sequentially, the above-described fuel blow-back and supercharging are prevented.

  In recent years, flattening of the fuel shut-off valve is also demanded along with the flattening of the fuel tank. However, according to the above-described conventional technology, an intermediate chamber is required between the upper chamber and the lower chamber. The shape of the shut-off valve in the height direction becomes large and cannot meet the demand for flattening of the fuel tank.

In addition, in Patent Document 3 as another conventional technique, a float having an inclined surface that descends obliquely downward is disposed in a portion facing the communication hole provided in the case side wall in order to suppress lift acting on the float during refueling. The structure to do is known. However, depending on the positional relationship between the float position (fin position) and the communication hole, the force acting on the inclined surface changes and becomes non-uniform, and the force pushing downward on the entire float becomes non-uniform.
JP-A-7-293384 US Pat. No. 5,535,772 JP 7-293382 A

  The present invention provides a fuel cutoff valve mechanism that contributes to the flattening of the fuel tank, smoothly fills the tank, and improves the accuracy of the full tank level, in light of solving the problems of the conventional technology. The purpose is to do.

The present invention made to solve the problems
In a fuel shut-off valve that is attached to the upper part of the fuel tank and that cuts off the communication between the inside and outside of the fuel tank according to the fuel level in the fuel tank.
A first valve chamber communicating with the fuel tank; a second valve chamber connected to the first valve chamber; a first connection passage connecting the first valve chamber and the second valve chamber; A casing having a second connection passage connecting the second valve chamber and the outside;
A first valve mechanism housed in the first valve chamber and rising when the fuel liquid level reaches the first liquid level and closing the first connection passage;
A second valve mechanism that is housed in the second valve chamber and rises when the fuel level reaches a second level higher than the first level, and closes the second connection passage;
The first valve mechanism is configured to reduce a flow rate from the first valve chamber to the second valve chamber so as to increase a tank internal pressure of the fuel tank when the first connection passage is closed, or the first valve mechanism A throttle part for reducing the flow rate into the fuel tank and the second valve chamber;
When the fuel liquid level reaches the first liquid level, a first float that rises due to buoyancy caused by the fuel flowing into the first valve chamber is provided, and the side communication is provided above the first float. An inclined surface that guides the airflow from the hole to the first connection passage and generates a component force that pushes the first float downward by the airflow is provided on the entire circumference obliquely downward from the seat surface of the first float. And

  When fuel is supplied to the fuel tank using the fuel shut-off valve according to the present invention and reaches the first liquid level, the fuel flows into the first valve chamber, and the first valve mechanism rises to pass through the first connection passage. close. In this state, the flow from the first valve chamber to the second valve chamber is reduced by the action of the throttle portion, and the tank internal pressure in the fuel tank increases. As the tank internal pressure rises, the liquid level in the inlet pipe rises, and an auto-stop functioning to stop refueling of the fuel gun is activated. In this way, the throttle portion reduces the flow rate from the inside of the fuel tank to the outside, but ensures the ventilation itself, so that the tank internal pressure can be prevented from rising rapidly and fuel blowback can be prevented. Further, when the fuel level reaches the second level, the second valve mechanism rises and closes the second connection passage, so that the fuel tank is sealed against the canister side. Can be prevented.

  In addition, when the throttle portion that reduces the flow rate from the first valve chamber to the second valve chamber is provided, the fuel cutoff valve includes the first valve chamber, the first connection passage, the throttle portion, and the second valve chamber. Since the fuel tank is connected in series to the outside through the second connection passage, it is not necessary to provide an intermediate chamber as described in the prior art, and downsizing can be realized. In addition, a so-called dead space in the tank where fuel does not accumulate near the upper wall of the fuel tank can be narrowed, the effective capacity of the fuel tank can be increased, and the second valve mechanism in the second valve chamber can be raised and lowered. Timing can be set easily and reliably. Furthermore, the fuel shut-off valve communicates with the outside of the fuel tank only through the second valve chamber, and only one seal connection is required in the second connection passage, so that the sealing performance is easily increased and the liquid leakage is prevented. Excellent effect.

  Further, an airflow from the side communication hole to the first connection passage is guided to the upper part of the first float, and an inclined surface that generates a component force that pushes the first float downward by the airflow is inclined from the seat surface of the first float. By providing the entire circumference downward, a force pushing downward acts on the entire float, the float does not tilt, and the auto-stop liquid level does not vary.

  As a preferred aspect of the present invention, the side wall of the first float includes a guide protrusion and a side wall extending part extending to an upper part of the guide protrusion, and the casing guides the guide protrusion. A hole is provided, and the guide protrusion and the guide hole can be configured to guide the first float in the vertical direction and prevent rotation. With this configuration, the inclined surface can be opposed to the side communication hole, air can be reliably ventilated, and the inclination of the first float can be prevented by arranging the side wall extending portion.

  As a preferred aspect of the present invention, the casing includes a first seal portion at an opening peripheral edge portion of the first connection passage, and the throttle portion is formed between the first valve mechanism and the first seal portion. The structure to do can be taken. The throttle portion is configured by an inter-valve passage that is connected to the first connection passage and has a part of the first seal portion cut out, or between the valves that has a part of the upper surface of the first valve mechanism cut out. It can consist of a passage. With these configurations, it is possible to prevent the inter-valve passage from being in close contact with the entire circumference of the first seal portion, and reduce the force with which the first valve mechanism is in close contact with the first seal portion. Can be prevented.

  As a preferred aspect of the present invention, the casing includes a side communication hole that is closed with fuel when the fuel liquid level reaches the second liquid level, and the side communication hole is formed in the tank. Due to the pressure difference between the internal pressure and the second valve chamber, the second valve mechanism can be configured to close the second connection passage by allowing fuel to flow from the first valve chamber to the second valve chamber. . With this configuration, the first liquid level can be set independently at the rising position of the first valve mechanism, and the second liquid level can be set independently at the position where the side communication hole is submerged. By doing so, the present invention can also be applied to a case where it is desired to reduce the amount of additional fuel supply in the flat fuel tank shape.

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 FIG. 1 is a side view showing a fuel cutoff valve 10 attached to the upper part of a fuel tank FT of an automobile according to a first embodiment of the present invention, and FIG. 10 is a plan view, and FIG. 3 is a cross-sectional view taken along line 3-3 in 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 regulates the outflow to the canister when the fuel in the fuel tank FT rises to the first liquid level FL1 during refueling, functions as an auto stop, and further exceeds when the fuel exceeds the second liquid level FL2. It prevents oiling.
(2) Configuration of Each Part of Fuel Shutoff Valve 10 In FIG. 3, the fuel cutoff valve 10 includes a casing 20, a first valve mechanism 50, and a second valve mechanism 60 as main components. The casing 20 includes a first casing part 30 and a second casing part 35 fixed on the first casing part 30, and the first valve mechanism is provided in the first valve chamber 31 </ b> S of the first casing part 30. 50 is accommodated, and the second valve mechanism 60 is accommodated in the second valve chamber 35 </ b> S of the second casing part 35.

  4 is an exploded cross-sectional view of the first casing portion 30 and the first valve mechanism 50, and FIG. 5 is an exploded perspective view of the first casing portion 30 and the first valve mechanism 50. The first casing part 30 is a cup surrounded by an upper wall 32 constituting a partition wall with the second casing part 35 (FIG. 3) and a side wall 33 formed in a cylindrical shape downward from the outer peripheral part of the upper wall 32. It is a shape and the lower part is made into the lower opening 30a. A first connection passage 32 a that communicates the first valve chamber 31 </ b> S and the second valve chamber 35 </ b> S (FIG. 3) is formed at the center of the upper wall 32. The opening periphery of the first connection passage 32a on the first valve chamber 31S side is a first seal portion 32b. The first seal portion 32b is formed with four inter-valve passages 32c in which a part of the first seal portion 32b is cut out at equal intervals of 90 ° in the circumferential direction. The side wall 33 is formed with four side communication holes 33a at equal intervals of 90 ° in the circumferential direction. The side communication hole 33a communicates the fuel tank FT and the first valve chamber 31S. On the upper surface of the upper wall 32, an upper plate 34a is supported by legs 34b, and a communication path 34c connected to the first connection path 32a is formed. A spring support portion 34d protrudes from the center upper surface of the upper plate 34a.

  The first valve mechanism 50 is housed in the first valve chamber 31 </ b> S and includes a first float 51. The first float 51 has a cup shape having a buoyancy chamber 51 </ b> S opened downward, and is formed of an upper wall 52 and a side wall 53 projecting in a cylindrical shape from the outer peripheral portion of the upper wall 52. The upper wall 52 includes a circular sheet surface 52a and an inclined surface 52c. The inclined surface 52c is formed on the entire circumference obliquely downward from the seat surface 52a of the first float 51, and a passage connected to the first connection passage 32a is formed along the space above the inclined surface 52c (see FIG. 3). ). On the side wall 53, a guide protrusion 53a and a side wall extending portion 53b are formed. The guide protrusion 53a enters the guide hole 33b to guide the vertical movement of the first float 51, and the inclined surface 52c faces the side communication hole 33a by the rotation of the first float 51. Is positioned. The side wall extending portions 53b are extended upward by four at equal intervals from the guide protrusion 53a, and prevent the first float 51 from being inclined. Further, the side wall extending portion 53b also serves to reliably guide the airflow flowing from the fuel tank FT to the first valve chamber 31S to the inclined surface 52c by suppressing the inflow of steam from the guide hole 33b.

  6 is an exploded sectional view showing the second casing part 35 and the second valve mechanism 60, and FIG. 7 is an exploded perspective view showing the second casing part 35 and the second valve mechanism 60. The 2nd casing part 35 is enclosed by the upper wall 36 and the cylindrical side wall 37, is a cup shape, and makes the lower part the lower opening 35a. A second connection passage 36a is formed in the upper wall 36, and an opening peripheral edge portion thereof serves as a second seal portion 36b. At the lower end of the side wall 37, a flange 37a projecting in the outer peripheral direction is formed. The flange 37a is integrated with the first casing part 30 by being welded to the upper stage part 32d of the first casing part 30 shown in FIG. A ventilation hole 37 b is formed in the upper part of the side wall 37. The air hole 37b is an air inlet for discharging the fuel accumulated in the second valve chamber 35S. A flange 38 for attaching to the tank upper wall FTa (see FIG. 3) extends from the outer peripheral portion of the upper wall 36. In addition, a tube portion 39 projects from the central portion of the upper wall 36. A lid side passage 39a connected to the second connection passage 36a is formed in the tube portion 39.

  The second valve mechanism 60 is housed in the second valve chamber 35 </ b> S, and includes a second float 62, an upper valve mechanism 65, and a spring 70. The second float 62 has a cup shape having a buoyancy chamber 62 </ b> S opened downward, and includes an upper wall 63 and a side wall 64 projecting in a cylindrical shape from the outer periphery of the side wall 64. A conical valve portion 63 a is formed at the center of the upper wall 63. On the side wall 64, four guide protrusions 64a are formed along the vertical direction and at equal intervals in the circumferential direction. The guide ridges 64a slide on the inner wall of the side wall 37 of the second casing portion 35 to guide the second float 62 so as to prevent the tilt when the second float 62 moves up and down. The second float 62 is supported by a spring 70 that spans between the lower surface of the upper wall 63 and the upper plate 34a (FIG. 4) of the first casing portion 30. The spring 70 is positioned by a spring support portion 34d on the upper plate 34a.

  The upper valve mechanism 65 is a valve for improving the restart valve characteristic, and is supported on the upper part of the second float 62 so as to be movable up and down. The valve support member 66 and the rubber valve body attached to the valve support member 66 are supported. 68. The valve support member 66 includes a disk-like support upper plate 66a. A valve passage projection 66b projects upward from the center of the valve support member 66, and a connection hole 66c passes through the valve passage projection 66b. A lower seal portion 66d is formed at the periphery of the lower opening of the connection hole 66c, and the valve portion 63a of the second float 62 is separated. On the outer periphery of the support upper plate 66a, four support arms 66e are protruded obliquely downward at an interval of 90 °. A guide hole 66f is formed in the support arm 66e, and the upper valve mechanism 65 is supported to be movable up and down by a predetermined distance with respect to the second float 62 by inserting the retaining protrusion 63b of the second float 62. .

A valve holding recess 66g is formed in the upper part of the valve support member 66 and on the outer periphery of the valve passage protrusion 66b. The rubber valve body 68 is supported by the valve support member 66 by press-fitting the support base 68a of the rubber valve body 68 into the valve holding recess 66g. The rubber valve body 68 includes a seat portion 68b on the outer peripheral portion of the support base portion 68a. The seat portion 68b is attached to and detached from the second seal portion 36b to open and close the second connection passage 36a.
(3) Operation of the fuel cutoff valve Next, the operation of the fuel cutoff valve 10 will be described. In FIG. 3, 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 as the fuel liquid level in the fuel tank FT rises is connected from the fuel cutoff valve 10 to the pipeline. It is escaped to the canister through. That is, while the fuel level in the fuel tank FT does not reach the first level FL1, the first float 51 and the second float 62 are respectively in the first valve chamber 31S and the second valve chamber 35S. Since the fuel vapor is separated from the seal portion 32b and the second seal portion 36b, the fuel vapor enters the second valve chamber 35S through the first valve chamber 31S and the first connection passage 32a, and then passes through the second valve chamber 35S. It flows into the canister through the connection passage 36a and the lid side passage 39a.

  As shown in FIG. 8, when the fuel level FL in the fuel tank FT further rises and reaches the first level FL1, the fuel flows into the first valve chamber 31S. When the buoyancy exceeds its own weight, the first float 51 quickly rises and sits on the first seal portion 32b to close the first connection passage 32a. In this state, the inter-valve passage 32c formed in the first seal portion 32b secures ventilation in a state where the passage area of the first connection passage 32a is narrowed, so that the fuel vapor in the fuel tank FT is in the side communication hole. 33a, through the passage above the inclined surface 52c of the first float 51, and further to the canister via the inter-valve passage 32c, the communication passage 34c, the second valve chamber 35S, the second connection passage 36a, and the lid side passage 39a. . At this time, the internal pressure of the fuel tank FT rises because it is throttled by the inter-valve passage 32c constituting the throttle portion. As the tank internal pressure rises, the liquid level in the inlet pipe rises, and an auto-stop functioning to stop refueling of the fuel gun is activated. However, the passage such as the inter-valve passage 32c secures the communication between the fuel tank FT and the canister at the time of auto-stop and avoids a sudden rise, thereby preventing the fuel from being blown back.

  Furthermore, as shown in FIG. 9, when the fuel level FL reaches the second level FL2, the side communication hole 33a is closed. In this state, the flow of fuel vapor to the second valve chamber 35S through the inter-valve passage 32c is cut off. The second valve chamber 35S is connected to the canister via the second connection passage 36a and the lid side passage 39a, and the internal pressure thereof is substantially equal to the atmospheric pressure. However, since the tank internal pressure of the fuel tank FT is higher than the atmospheric pressure, the fuel quickly flows into the second valve chamber 35S through the first valve chamber 31S and the inter-valve passage 32c due to the pressure difference. When the fuel level in the second valve chamber 35S reaches the height h1, the buoyancy of the second float 62 and the upward force due to the weight of the spring 70, the second float 62 and the upper valve mechanism 65 are provided. Due to the balance with the downward force due to the weight of the two-valve mechanism 60, when the former exceeds the latter, the second valve mechanism 60 rises and the seat portion 68b of the rubber valve body 68 is seated on the second seal portion 36b. Then, the second connection passage 36a is closed. Thereby, the passage connected to the canister is closed and the inside of the fuel tank FT is sealed with respect to the canister side, so that the supercharging by the fuel gun can be prevented.

Furthermore, as shown in FIG. 10, when the fuel in the fuel tank FT is consumed and the fuel level FL is lowered, the second float 62 is slightly lowered with its buoyancy reduced. As the second float 62 descends, the valve portion 63a of the second float 62 moves away from the lower seal portion 66d and opens the connection hole 66c. By connecting the connection hole 66c, the pressure below the upper valve mechanism 65 becomes the same pressure as the vicinity of the second connection passage 36a. Then, when the upper valve mechanism 65 is lowered, the seat portion 68b of the rubber valve body 68 is separated from the second seal portion 36b, the second connection passage 36a is opened, and the inside of the fuel tank FT is opened to the canister side. . Thus, the two-stage valve structure by the second float 62 and the upper valve mechanism 65 functions to promote the improvement of the restart valve characteristic. At this time, since the valve hole 63a is separated from the lower seal part 62d and the connection hole 66c having a small passage area is communicated first, the pressure at the lower part of the upper valve mechanism 65 is reduced and the upper valve mechanism 65 is closed in the valve closing direction. The force is reduced, so the restart valve characteristics are excellent.
(4) Actions and effects of the embodiment The following actions and effects are exhibited by the configuration of the above embodiment.
(4) -1 When the fuel level in the fuel tank FT exceeds the first liquid level FL1 due to refueling, the first float 51 closes a part of the first connection passage 32a and the tank internal pressure of the fuel tank FT increases. So, you can work auto stop. In this state, the inter-valve passage 32c releases the internal pressure of the fuel tank FT to the canister side through the second valve chamber 35S and the like, so that the fuel can be prevented from blowing back.
(4) -2 Since the fuel shut-off valve 10 does not require an intermediate chamber as described in the prior art, it is possible to narrow a tank space in which fuel does not accumulate near the upper wall of the fuel tank FT, a so-called dead space. Therefore, the effective capacity of the fuel tank FT can be increased.
(4) -3 When the fuel level FL reaches the second level FL2 higher than the first level FL1 due to refueling, the second valve mechanism 60 closes the second connection passage 36a and moves the fuel tank FT to the canister side. Therefore, supercharging can be prevented.
(4) -4 The first liquid level FL1 can be set independently at the rising position of the first float 51, and the second liquid level FL2 can be set independently at the position in the height direction of the side communication hole 33a. By setting the distance small, the shape in the height direction is not increased. Therefore, the present invention can be applied to a flat fuel tank shape where it is desired to reduce the additional amount of fuel.
(4) -5 The vent 37b shown in FIG. 10 discharges the fuel that has entered the second valve chamber 35S from the second valve chamber 35S into the fuel tank FT as the fuel level FL in the fuel tank FT decreases. Therefore, the fuel in the second valve chamber 35S is quickly discharged, the second valve mechanism 60 opens the second connection passage 36a, and vents the fuel tank FT to the canister side. Can be secured.
(4) -6 Since the passage from the fuel shut-off valve 10 to the canister side is only the second connection passage 36a and the seal portion is only one portion of the second seal portion 36b, the seal is made with a simple configuration. It is excellent in the effect of improving the property and preventing the liquid leakage.
(4) -7 As shown in FIG. 3, when the fuel level approaches the first liquid level FL1 and the first float 51 rises, the airflow flowing from the side communication hole 33a to the first connection passage 32a increases. . At this time, ascending force is applied by the Bernoulli theorem to suck the first float 51 toward the first connection passage 32a, but the force F0 pushing the inclined surface 52c by the airflow flowing from the side communication hole 33a to the first connection passage 32a is The force applied to the inclined surface 52c is divided into a component force F1 applied perpendicularly to the inclined surface 52c and a component force F2 along the inclined surface 52c, and the component force F1 further lowers the first float 51. Acts as a component force F1a. Further, since the inclined surface is formed on the entire circumference, the airflow can be spread over the entire inclined surface, and a force that pushes downward uniformly is applied to the entire first float, so that the posture of the first float 51 is stable. However, the auto-stop liquid level does not vary.
(4) -8 The inter-valve passage 32c of the first seal portion 32b is formed by cutting out a part of the first seal portion 32b, so that when the seat is seated on the seat surface 52a of the first float 51, The sheet surface 52a of the 1 float 51 can prevent sticking to the 1st seal | sticker part 32b.

  The present invention is not limited to the above embodiment, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

  In the above embodiment, the throttle portion is configured as the inter-valve passage 32c in which a part of the first seal portion 32b is cut out. However, the throttle portion may be provided on the upper wall 32 or the second valve chamber 35S may be formed. 2 You may provide in the side wall 37 of the casing part 35. FIG.

  Moreover, although the said Example demonstrated the structure attached so that the attachment hole formed in the tank upper wall might be plugged up, the structure attached to the upper part in a fuel tank by not only this but a so-called in-tank type may be sufficient.

It is a side view which shows the fuel cutoff valve attached to the upper part of the fuel tank of the motor vehicle concerning 1st Example of this invention. It is a top view of a fuel cutoff valve. FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 2. It is sectional drawing which decomposed | disassembled the 1st casing part and the 1st valve mechanism. It is the perspective view which decomposed | disassembled the 1st casing part and the 1st valve mechanism. It is sectional drawing which decomposed | disassembled the 2nd casing part and the 2nd valve mechanism. It is the perspective view which decomposed | disassembled the 2nd casing part and the 2nd valve 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 explanatory drawing explaining the operation | movement following FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fuel cutoff valve 20 ... Casing 30 ... 1st casing part 30a ... Lower opening 31S ... 1st valve chamber 32b ... 1st seal part 32 ... Upper wall 32a. .. First connection passage 32c ... Inter-valve passage 32d ... Upper step 33 ... Side wall 33a ... Side communication hole 33b ... Guide hole 34a ... Upper plate 34b ... Leg 34c ... Communication passage 34d ... Spring support portion 35 ... Second casing portion 35S ... Second valve chamber 35a ... Lower opening 36 ... Upper wall 36a ... Second connection passage 36b ... Second seal part 37 ... Side wall 37a ... Flange 37b ... Vent hole 38 ... Flange 39 ... Tube part 39a ... Cover side passage 50 ... First valve mechanism 51 ... first float 51S ... buoyancy chamber 52 ... upper wall 52a ... seat surface 52c ... inclined surface 53 ... side wall 53a ... guide protrusion 53b ... side wall extension Part 60 ... second valve mechanism 62S ... buoyancy chamber 62 ... second float 3 ... Upper wall 63a ... Valve part 63b ... Stop projection 64 ... Side wall 64a ... Guide projection 65 ... Upper valve mechanism 66 ... Valve support member 66a ... On support Plate 66b ... Valve passage protrusion 66c ... Connection hole 66d ... Lower seal part 66e ... Support arm 66f ... Guide hole 66g ... Valve holding recess 68 ... Rubber valve body 68a ... support base 68b ... seat part 70 ... spring FT ... fuel tank FTa ... tank upper wall FTb ... mounting hole FL1 ... first liquid level FL2 ... second liquid Place

Claims (5)

A fuel cutoff valve mounted on an upper portion of the fuel tank (FT) and configured to cut off communication between the inside of the fuel tank (FT) and the outside according to a fuel level in the fuel tank (FT);
A first valve chamber (31S) communicating with the fuel tank (FT); a second valve chamber (35S) connected to the first valve chamber (31S); the first valve chamber (31S); A casing (20) having a first connection passage (32a) connecting the second valve chamber (35S), and a second connection passage (36a) connecting the second valve chamber (35S) and the outside; ,
A first valve mechanism (50) housed in the first valve chamber (31S) and rising when the fuel liquid level reaches the first liquid level (FL1) and closing the first connection passage (32a); ,
The fuel is stored in the second valve chamber (35S) and rises when the fuel liquid level reaches a second liquid level (FL2) higher than the first liquid level (FL1) and passes through the second connection passage (36a). A second valve mechanism (60) for closing;
With
The casing (20) includes the first valve chamber (50) so as to increase the tank internal pressure of the fuel tank (FT) when the first valve mechanism (50) closes the first connection passage (32a). 31S) having a throttle part for reducing the flow rate from the second valve chamber (35S) or a throttle part for reducing the flow rate in the fuel tank (FT) and the second valve chamber (35S),
When the fuel level reaches the first level (FL1), a first float (51) that rises due to buoyancy generated by the fuel flowing into the first valve chamber (31S) is provided. An inclination that induces an airflow from the side communication hole (33a) to the first connection passage (32a) and pushes the first float (51) downward by the airflow at the upper part of one float (51). A fuel cutoff valve characterized in that a surface (52c) is provided obliquely downward and all around the seat surface (52a) of the first float (51). The fuel cutoff valve according to claim 1,
The side wall (53) of the first float (51) includes a guide protrusion (53a) and a side wall extension (53b) extending upward from the guide protrusion (53a), and the casing (20). Includes a guide hole (33b) for guiding the guide protrusion (53a), and the guide protrusion (53a) and the guide hole (33b) guide the first float (51) in the vertical direction. A fuel shut-off valve configured to prevent rotation. The fuel cutoff valve according to claim 2,
The casing (20) includes a first seal portion (32b) at an opening peripheral edge portion of the first connection passage (32a), and the throttle portion includes the first valve mechanism (50) and the first seal portion ( 32b) is a fuel shut-off valve. The fuel cutoff valve according to claim 2,
The throttle part is a fuel cutoff valve formed from an inter-valve passage (32c) that is connected to the first connection passage (32a) and cuts out a part of the first seal portion (32b). The fuel cutoff valve according to claim 2,
The casing (20) includes a side communication hole (33a) that is closed with fuel when the fuel level reaches the second liquid level (FL2), and the side communication hole (33a) Due to the pressure difference between the tank internal pressure and the second valve chamber (35S), fuel flows into the second valve chamber (35S) from the first valve chamber (31S), and the second valve mechanism (60) A fuel cutoff valve configured to close the second connection passage (36a).

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