JP4270091B2 - Fuel shut-off valve - Google Patents

Description

  The present invention relates to a fuel cutoff valve that is mounted on an upper portion of a fuel tank and that cuts off the communication between the fuel tank and the outside according to the fuel level in the fuel tank.

  Conventionally, as a fuel shut-off valve of this type, the technique of Patent Document 1 is known. That is, the conventional fuel cutoff valve includes a casing having a connection passage connected to the outside of the fuel tank, a cylindrical float valve disposed in a valve chamber in the casing, and a spring that supports the float valve. When the fuel level exceeds a predetermined level, the connection passage is closed with a float valve. A bottom plate is mounted in the vertical direction on the lower part of the casing. The bottom plate is provided so as to close the communication hole that communicates with the valve chamber by moving up and down. When the fuel level rises abruptly when the vehicle suddenly turns, the fuel hits the bottom plate and closes the communication hole, thereby preventing the fuel from flowing out from the fuel tank to the canister.

  However, the conventional fuel shut-off valve has a problem that it is difficult to support the bottom plate so that it can be moved up and down smoothly, and that the fuel cannot be shut off quickly during a sudden turn.

Japanese Patent Laid-Open No. 11-254980

  The present invention solves the above-mentioned problems of the prior art, and is a fuel shut-off valve that closes quickly even when there is a sudden swing of fuel when the vehicle turns suddenly and does not allow the fuel in the fuel tank to flow outside. Is intended to be provided with a simple configuration.

The present invention made to solve the above problems
In the fuel shut-off valve that is mounted on the upper part of the fuel tank and cuts off the communication between the fuel tank and the outside according to the fuel level in the fuel tank.
A casing having a casing body forming a valve chamber communicating with the inside of the fuel tank, a bottom plate provided at a lower portion of the casing body , and a connection passage connecting the outside of the fuel tank and the valve chamber;
A first float disposed in the valve chamber so as to be movable up and down, and having a valve portion that opens and closes the connection passage by being raised and lowered by fuel in the valve chamber;
The float main body is disposed below the first float so as to be movable up and down and forms a buoyancy chamber, and has a vent hole formed in the upper portion of the float main body and venting the buoyancy chamber to the outside. A second float formed;
With
The first float has an upper plate portion having the valve portion, and protrudes downward from the outer peripheral portion of the upper plate portion, and surrounds the outer peripheral portion of the second float and is placed on the lower portion of the bottom plate. When the liquid level rises, it is configured to rise by its buoyancy and close the connection passage.
The second float is configured not to rise by filling the buoyancy chamber with fuel while the gas in the buoyancy chamber escapes to the valve chamber through the vent hole when the liquid level rises at a predetermined speed,
Further, when the liquid level rises larger than the predetermined speed, the second float rises due to the buoyancy of the buoyancy chamber due to the gas accumulated in the buoyancy chamber, and pushes up the first float, thereby The first float is configured to close the connecting passage;
It is characterized by.

  In the fuel shut-off valve according to the present invention, when the fuel level of the fuel tank rises when the vehicle is tilted, the fuel tank communicates with the outside via the valve chamber and the connection passage, and the fuel vapor in the fuel tank is discharged. Escape outside. On the other hand, when the fuel level in the fuel tank rises and buoyancy occurs in the first float, the first float rises and closes the connection passage to prevent the fuel in the fuel tank from flowing out. To do.

  At this time, since the specific gravity of the second float is larger than that of the fuel and the rising speed of the fuel liquid level is slow when tilted, the gas in the buoyancy chamber does not escape through the vent hole and does not increase the buoyancy of the buoyancy chamber. Therefore, since the connection passage can be opened and closed by raising and lowering only the first float at a liquid level higher than the liquid level at which the second float is submerged, it is preferable to set the valve closing liquid level to a high liquid level. It can also be applied to a system using a flat tank. On the other hand, when the rising speed of the fuel level is large, such as when the vehicle is turning sharply, the second float rises due to the buoyancy of the buoyancy chamber due to the gas accumulated in the buoyancy chamber, and pushes up the first float, thereby The float closes the connecting passage. Therefore, when the fuel level rises abruptly, such as when the vehicle turns sharply, it is possible to follow the rising speed of the fuel level and close the connection passage quickly.

As a preferred aspect of the present invention, the first float may be configured to be supported by a spring placed on the upper surface of the second float. Moreover, as a suitable aspect of the first float, an upper plate portion having a valve portion, and leg portions that protrude downward from the outer peripheral portion of the upper plate portion and are arranged so as to surround the outer peripheral portion of the second float It can take the composition provided with. Furthermore, the 1st float can be taken from the lower surface of an upper board part, and can take the structure which provides the guide mechanism supported by a casing.
As another preferred aspect of the present invention, the casing includes a bottom plate that supports the lower end of the second float, and the first float is supported by a spring placed on the upper surface of the bottom plate. it can.

  In order to further clarify the configuration and operation of the present invention described above, preferred embodiments of the present invention will be described below.

(1) Schematic configuration of the fuel cutoff valve 10
FIG. 1 is a cross-sectional view showing a fuel cutoff valve 10 attached to an upper portion of a fuel tank FT of an automobile according to a first embodiment of the present invention. The fuel cutoff valve 10 is a so-called in-tank type that is mounted in the fuel tank FT. In FIG. 1, a fuel shut-off valve 10 is a valve that regulates the outflow of fuel to the outside when the fuel in the fuel tank FT rises when the vehicle is tilted or when the vehicle is turning sharply. The fuel cutoff valve 10 includes a casing 20, a first float 40, a second float 50, and a spring 56 as main components. A valve mounting portion 21 is integrally formed on the upper portion of the casing 20 and is mounted in the fuel tank FT via a bracket BK welded to the lower surface of the tank upper wall FTa of the fuel tank FT.

(2) Configuration of Each Part Hereinafter, the configuration and operation of each part of the fuel cutoff valve 10 will be described. FIG. 2 is an exploded cross-sectional view of the fuel cutoff valve 10.
(2) -1 Casing 20
The casing 20 includes a casing body 30 and a bottom plate 35 attached to the lower part of the casing body 30. The casing body 30 includes a ceiling wall portion 32 and a side wall portion 33 extending in a cylindrical shape downward from the ceiling wall portion 32, and is a cup-shaped valve surrounded by the ceiling wall portion 32 and the side wall portion 33. A chamber 30S is formed, and a lower portion thereof is a lower opening 30a. A connection passage 32b passes through the center of the ceiling wall portion 32, and the valve chamber 30S side of the connection passage 32b is a seat portion 32c. An engaging claw 33 a is formed at the lower portion of the side wall portion 33. The engaging claw 33 a is for attaching the bottom plate 35. The bottom plate 35 is a member that closes the lower opening 30a of the casing main body 30. By engaging the engaging claws 33a of the casing main body 30 with the engaging holes 35a formed in the outer peripheral portion thereof, the bottom plate 35 It is mounted so as to close the opening 30a. A tubular body portion 37 protruding from the center to the side is formed on the upper portion of the casing body 30. A lid side passage 37a is formed in the tube part 37. One end of the lid side passage 37a is connected to the valve chamber 30S via the connection passage 32b of the casing body 30, and the other end is connected to the canister side. It is connected.

(2) -2 First float 40
FIG. 3 is a perspective view showing the first float 40, the second float 50, and the like. The first float 40 includes a disk-shaped upper plate portion 41 and a plurality of leg portions 42 (eight in the drawing) projecting downward from the outer periphery of the upper plate portion 41. The plurality of leg portions 42 are arranged at equal intervals in the circumferential direction of the upper plate portion 41. As shown in FIG. 2, a recess opened downward is formed on the lower surface of the upper plate portion 41, and this recess serves as a buoyancy chamber 40S. The first float 40 has a specific gravity (0.75 to 1.5) larger than the specific gravity of the fuel, and is made of, for example, polyacetal or polyamide. A substantially conical valve portion 41 a protrudes from the central portion of the upper plate portion 41. The valve portion 41a is formed to open and close the connection passage 32b by being attached to and detached from the seat portion 32c.

(2) -3 Second float 50
The second float 50 is disposed below and inside the first float 40. The second float 50 includes a float main body 51. The float body 51 includes an upper plate portion 52 and a cylindrical side wall portion 53 formed downward from the outer peripheral portion of the upper plate portion 52, has a cup shape opened downward, and is opened downward. The buoyancy chamber 50S is provided. A spring support portion 52b is formed on the upper surface of the upper plate portion 52, and the lower end of the spring 56 is supported by the spring support portion 52b, whereby the first float 40 is supported above the upper plate portion 52. . Further, the upper plate portion 52 has one vent hole 52a (hole area: 0.2 mm ² ) for ventilating the buoyancy chamber 50S and the valve chamber 30S in the center and four in the peripheral portion. The second float 50 has a specific gravity (0.75 to 1.5) larger than the specific gravity of the fuel, and is made of, for example, polyacetal, polyamide, and a foam thereof. Here, the specific gravity of the second float 50 is preferably slightly heavier than the specific gravity of the fuel of about 0.75 to 1.1. When the specific gravity is set as described above, the second float 50 operates even when the liquid level rises rapidly, and the first float 40 can quickly close the connection passage 32b by bending the spring 56.

(3) Operation of the fuel cutoff valve 10 (3) -1 Operation of the fuel cutoff valve 10 when the vehicle is tilted FIG. 4 is an explanatory diagram for explaining the operation of the fuel cutoff valve 10 when the vehicle is tilted. When the vehicle is tilted on an inclined road such as a slope from the opened state of the fuel cutoff valve 10 shown in FIG. 1, the fuel level gradually rises. When the liquid level reaches the fuel cutoff valve 10 and further rises, the liquid fuel flows into the valve chamber 30S through the communication hole 35b. At this time, since the rising speed of the fuel liquid level is not fast, the air in the buoyancy chamber 50S does not escape through the vent hole 52a even if the fuel liquid level rises, and does not function as the buoyancy chamber 50S. Since the specific gravity of 50 is larger than that of the fuel, the second float 50 does not rise. Then, as shown in FIG. 4, when the fuel reaches the predetermined liquid level FL1, the first float 40 is lifted by the buoyancy caused by the buoyancy chamber 40S and the leg portion 42, and the valve portion 41a is seated on the seat portion 32c. 32b is closed. On the other hand, when the fuel level in the fuel tank is lowered, the first float 40 is lowered with its buoyancy lowered and opens the connection passage 32b.

(3) -2 Operation of the fuel cutoff valve 10 when the vehicle swings FIG. 5 is an explanatory diagram for explaining the operation of the fuel cutoff valve 10 when the vehicle suddenly turns. When the fuel liquid level is close to the predetermined liquid level FL2 that is the full liquid level and the fuel tank FT is swung due to the sudden turning of the vehicle, the liquid level in the fuel tank FT is indicated by a two-dot chain line in FIG. Shake as shown. The fuel flows into the valve chamber 30 </ b> S through the communication hole 35 b of the bottom plate 35. At this time, the rising speed of the fuel liquid level is large, and since the amount of air passing through the vent hole 52a of the second float 50 is small, the buoyancy due to the air accumulated in the buoyancy chamber 50S increases. When the buoyancy exceeds the weight of the second float 50 and the force received from the spring 56, the second float 50 floats while the spring 56 is bent. The second float 50 is lifted to push up the first float 40 via the spring 56, whereby the valve portion 41a is seated on the seat portion 32c and the connection passage 32b is closed. Accordingly, it is possible to prevent the fuel from flowing out from the fuel tank FT when the vehicle turns suddenly.

(3) -3 Operation of the fuel shut-off valve 10 when the vehicle falls When the vehicle falls, the fuel shut-off valve 10 is turned upside down and submerged. At this time, the first float 40 and the second float 50 sink because they have a higher specific gravity than the fuel, and the second float 50 pushes the first float 40 downward via the spring 56. As a result, the valve portion 41a of the first float 40 is seated on the seat portion 32c and closes the connection passage 32b. Therefore, it is possible to prevent the fuel from flowing out at the time of falling.

(4) Operation / Effect of Fuel Shutoff Valve 10 The following operation / effect is achieved by the configuration of the above embodiment.
(4) -1 When the rising speed of the fuel level when the vehicle is tilted is small, the first float 40 rises quickly and closes the connection passage 32b, so that the fuel can be prevented from flowing out. Further, since the connection passage 32b can be opened and closed by raising and lowering only the first float 40 at a liquid level higher than the liquid level at which the second float 50 is submerged, the valve closing liquid level is set to a high liquid level. It is possible to cope with a system using a flat tank.

(4) -2 When the fuel liquid level suddenly rises, such as when the vehicle is turning sharply, the second float 50 is unable to vent through the vent hole 52a and the ascending force due to the collision of the fuel with its lower surface. The first float 40 can be pushed via the spring 56 and the connection passage 32b can be quickly closed by the valve portion 41a due to the rising force generated by the accompanying buoyancy.

(4) -3 The first float 40 is supported by placing the leg portion 42 of the first float 40 on the bottom plate 35, and the second float 50 is accommodated in the inner space. Therefore, as compared with the configuration in which the second float is supported on the first float via the spring, the first float 40 is directly supported by the bottom plate 35 via the leg portion 42, so that the height of the second float 50 is increased. The height of the fuel cutoff valve 10 can be determined without depending on the height. Therefore, the height of the fuel cutoff valve 10 itself can be reduced, which can contribute to flattening of the fuel tank FT.

(4) -4 When the vehicle suddenly turns, the rising force of the second float 50 is changed to the urging force of the spring 56 and the first float 40 is strongly pushed up in the valve closing direction. High sealing performance can be obtained.

(4) -5 The leg portion 42 of the first float 40 is submerged in the fuel when the vehicle is tilted and contributes to buoyancy, and the buoyancy chamber 40S can be reduced by that much, so the shape of the first float 40 can be reduced in size. This contributes to the miniaturization of the fuel cutoff valve 10 and the flattening of the fuel tank FT.

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

  FIG. 6 is a sectional view showing a fuel cutoff valve 10B according to the second embodiment. The second embodiment is characterized by the configuration of the guide mechanism 60 that supports the first float 40B and the second float 50B. That is, the guide mechanism 60 is a guide cylinder having a guide portion 61 projecting from the central lower surface of the first float 40B and a through hole 62a formed in the second float 50B and slidably supporting the guide portion 61. Part 62. According to the second embodiment, in addition to the effects of the first embodiment, the guide mechanism 60 can reliably perform positioning when the first float 40B and the second float 50B are moved up and down. Further, when the second float 50 </ b> B rises during a sudden turn, the upper end 62 b of the guide cylinder portion 62 pushes up the stepped portion 61 a of the guide portion 61. Therefore, since the second float 50B directly pushes up the first float 40B, a quick valve closing characteristic can be obtained.

  FIG. 7 is a sectional view showing a fuel cutoff valve 10C according to the third embodiment. The third embodiment is characterized by the configuration of a spring 56C and the like that support the first float 40C. That is, a guide portion 71 projects from the lower surface of the center of the first float 40C, and the guide portion 71 penetrates the through hole 52Ca of the second float 50C and further the bottom plate 35C constituting the casing 20C. The through hole 35Ca is slidably supported by the bottom plate 35C. Further, a spring 56C is placed on the upper surface of the bottom plate 35C and penetrates the through hole 52Ca of the second float 50C to support the lower portion of the first float 40C. When the second float 50C rises during a sudden turn, the upper plate portion 52C of the second float 50C pushes up the lower end of the upper plate portion 41C of the first float 40C. Therefore, according to the third embodiment, as in the second embodiment, the second float 50C directly pushes up the first float 40C during a sudden turn, so that quick valve closing characteristics can be obtained.

  In the above-described embodiment, the configuration in which the second float is not supported by the spring has been described. However, the present invention is not limited to this, and the second float may be supported by the spring to reduce the apparent specific gravity.

  In the above embodiment, the in-tank type in which the fuel shut-off valve is mounted in the fuel tank has been described. The present invention can also be applied to a type in which the lower part of the fuel cutoff valve is inserted. Moreover, although the fuel tank demonstrated the fuel cutoff valve attached to an iron fuel tank via a bracket, it is not restricted to this, It can apply to the various fuel tank formed with the composite material containing polyethylene. According to this configuration, the casing can be attached to the fuel tank without using a bracket by heat-welding the casing to the fuel tank, so that the number of parts can be reduced.

It is sectional drawing 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 sectional drawing which decomposes | disassembles and shows a fuel cutoff valve. It is a perspective view which decomposes | disassembles and shows the main components of a fuel cutoff valve. It is explanatory drawing explaining operation | movement of the fuel cutoff valve at the time of tilting of a vehicle. It is explanatory drawing explaining operation | movement of the fuel cutoff valve at the time of sudden turning of a vehicle. It is sectional drawing which shows the fuel cutoff valve concerning 2nd Example. 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 21 ... Valve mounting part 30 ... Casing main body 30S ... Valve chamber 30a ... Lower opening 32 ... Ceiling wall part 32b ... Connection passage 32c ... sheet part 33 ... side wall part 33a ... engagement claw 35 ... bottom plate 35a ... engagement hole 35b ... communication hole 37 ... tubular part 37a ... lid side Passage 40 ... first float 40S ... buoyancy chamber 41 ... upper plate part 41a ... valve part 42 ... leg part 50 ... second float 50S ... buoyancy chamber 51 ... Float body 52 ... Upper plate part 52a ... Vent hole 52b ... Spring support part 53 ... Side wall part 56 ... Spring 10B ... Fuel cutoff valve 40B ... First float 50B .. Second float 60 ... Guide mechanism 61 ... Guide part 61a ... Step part 62 ... Guide cylinder part 62a ... Through hole 62b ... Upper end 10C ... Fuel shut-off valve 20C ... Casing 35C ... Bottom plate 35Ca ... Through hole 40C ... No. Float 41C ... Upper plate part 50C ... Second float 52C ... Upper plate part 52Ca ... Through hole 56C ... Spring 71 ... Guide part BK ... Bracket FT ... Fuel tank FTa ... Tank upper wall

Claims (4)

A fuel cutoff valve that is mounted on the upper part of the fuel tank (FT) and that cuts off the communication between the fuel tank (FT) and the outside in accordance with the fuel level in the fuel tank (FT).
A casing body (30) forming a valve chamber (30S) communicating with the fuel tank (FT), a bottom plate (35) provided at a lower portion of the casing body (30), and an outside of the fuel tank (FT) And a casing (20) having a connection passage (32b) connecting the valve chamber (30S),
A first float (40) disposed in the valve chamber (30S) so as to be movable up and down, and having a valve portion (41a) for opening and closing the connection passage (32b) by moving up and down with fuel in the valve chamber (30S); ,
A float main body (51) which is disposed below the first float (40) so as to be movable up and down and forms a buoyancy chamber (50S), and an buoyancy chamber (50S) formed at the upper part of the float main body (51). A second float (50) having a ventilation hole (52a) for ventilating and formed with a specific gravity greater than the fuel,
With
The first float (40) includes an upper plate portion (41) having the valve portion (41a), and protrudes downward from an outer peripheral portion of the upper plate portion (41). A leg portion (42) that surrounds the outer peripheral portion and is placed on the lower portion of the bottom plate (35), and rises due to the buoyancy when the liquid level rises, and the connection passage (32b) is configured to close,
When the liquid level rises at a predetermined speed, the second float (50) allows the gas in the buoyancy chamber (50S ) to escape to the valve chamber (30S) through the vent hole (52a) while the buoyancy chamber (50S) 50S) is configured not to rise by filling the fuel ,
Furthermore, the second float (50) rises due to the buoyancy of the buoyancy chamber (50S) by the gas accumulated in the buoyancy chamber (50S) when the liquid level rises greater than the predetermined speed, The first float (40) is configured to close the connection passage (32b) by pushing up the first float (40);
A fuel shut-off valve characterized by The fuel cutoff valve according to claim 1,
The first float (40) is a fuel cutoff valve supported by a spring (56) placed on the upper surface of the second float (50). The fuel cutoff valve according to claim 1 or 2 ,
The first float (40B) is a fuel cutoff valve that protrudes from the first float (40B) and has a guide mechanism (60) supported by the second float (50B) and the casing (20). The fuel cutoff valve according to claim 1,
The casing (20C) includes a bottom plate (35C) that supports a lower end of the second float (50C). The first float (40C) is a spring (56C) placed on the upper surface of the bottom plate (35C). Fuel shut-off valve supported by

Images