JP4301086B2 - Fuel shut-off valve - Google Patents

Description

  The present invention relates to a fuel cutoff valve that is attached to an upper part of a fuel tank and that opens and closes a connection passage that connects the inside and outside of the fuel tank to cut off communication between the fuel tank and the outside.

  Conventionally, as this kind of fuel cutoff valve, patent document 1 etc. are known and it is a structure as shown in FIG. FIG. 9 is a cross-sectional view showing the fuel cutoff valve 100 mounted on the upper portion of the fuel tank. The fuel cutoff valve 100 includes a casing 110 having a valve chamber 110S that communicates the inside and outside of the fuel tank, a float 120 that is housed in the valve chamber 110S and moves up and down according to the liquid level in the fuel tank, and an upper part of the float 120. A spring 122 placed, a first valve body 124 placed on the upper end of the spring 122, and a second valve body 126 placed in the upper center of the float 120 are provided.

  In the configuration of the fuel shut-off valve 100, when the fuel level in the fuel tank exceeds the first fuel level due to refueling, the float 120 rises and the first valve body 124 becomes the first connection passage. 112b is closed, and when the second fuel liquid level that is higher than the first fuel liquid level is exceeded, the second valve body 126 resists the urging force of the spring 122 and the second fuel liquid level. The connection passage 131a is closed. The passage area of the second connection passage 131a is narrower than that of the first connection passage 112b, that is, the passage area is narrowed in two steps according to the fuel level, so that the fuel tank is not abruptly sealed. Further, it is possible to prevent the fuel from blowing back from the fuel filler opening.

  However, since the fuel cutoff valve 100 determines the second fuel liquid level at which the second valve body 126 is closed by the load of the spring 122, a great amount of labor is required for setting the load of the spring 122 and the assembly process. It was.

  As another technique, a configuration is known in which supercharging is prevented by sequentially opening and closing two connection passages with two rubber valve bodies (Patent Document 2). However, in this configuration, since two rubber valve bodies are used, the configuration becomes complicated, and the restart valve characteristics are not good.

JP 2000-130271 A JP-A-7-280117

  An object of the present invention is to provide a fuel shut-off valve that can prevent fuel blow-back during refueling with a simple configuration in view of the above-described problems of the conventional technology.

The present invention made to solve the above problems
In a fuel cutoff valve that is mounted on the upper part of the fuel tank and cuts off communication between the inside and outside of the fuel tank,
A casing having a valve chamber communicating with the fuel tank;
A float that is housed in the valve chamber and moves up and down according to the fuel level in the fuel tank, and a seat member that is formed of a flexible material and is mounted so as to form a float upper chamber above the float A valve body mechanism having
A connection passage that connects the valve chamber and the outside, and is opened and closed by raising and lowering the float;
With
The seat member has a valve body air hole that penetrates and connects the float upper chamber and the valve chamber,
The connection passage is provided at an upper portion of the casing and connects the valve chamber and the outside. The connection passage is connected to the first connection passage and has a smaller passage area than the first connection passage. A valve body vent hole and a second connection passage having the float upper chamber as a path,
When the fuel level rises to the first fuel level, the second connection passage is maintained in an open state and the first connection passage is closed by the seat member,
When the fuel liquid level rises to a second fuel liquid level higher than the first fuel liquid level, the seat member is elastically deformed and is in close contact with the upper part of the float so that the second connection passage is It is characterized by being closed.

  When the fuel is supplied to the fuel tank using the fuel shutoff valve according to the present invention, the fuel vapor accumulated in the upper part of the fuel tank as the fuel liquid level in the fuel tank rises escapes to the canister side through the connection passage. It is. When the fuel level in the fuel tank reaches a predetermined first fuel level, the float rises due to buoyancy, and the seat member closes a part of the first connection passage. At this time, since the second connection passage is maintained in an open state, the first connection passage is narrowed, that is, the tank internal pressure rises due to the influence of the narrowed portion, and the fuel liquid in the filler pipe increases. The rank rises.

  The sensor detects the increase in the tank internal pressure or detects that the fuel in the filler pipe has reached the fuel gun, so that an automatic stop for stopping the fuel supply of the fuel gun can be activated. Even if is closed, the second connection passage is secured, so that the tank internal pressure does not rise rapidly, and the accompanying fuel blowback from the fuel filler port can be prevented.

  When fuel is further supplied and the fuel level reaches the second fuel level, the float is further raised, and the seat member is elastically deformed to be in close contact with the upper portion of the float, thereby closing the second connection passage. Thereby, the inside of the fuel tank is sealed with respect to the canister side to prevent the fuel from flowing out.

  In the fuel shut-off valve according to the present invention, the seat member is formed of a flexible material. After the seat member is seated at a different fuel level and the passage area of the first connection passage is reduced, the second connection passage is provided. As described in the prior art, there is no need to use a two-stage float or a spring, and the structure is simple and the assembly process is simplified. In addition, there is no need to adjust the spring load.

  Further, since the opening area of the second connection passage is smaller than that of the first connection passage, the seat member is closed via the second connection passage when the fuel level in the fuel tank decreases. The pressure receiving area that receives the differential pressure in the valve direction is small. In addition, when the seat member is seated on the first and second seal portions, an elastic force is generated to lower the float by elastic deformation. Therefore, since the float descends quickly and the seat member opens the second connection passage, the fuel cutoff valve according to the present invention smoothly performs the valve opening operation of opening the first and second connection passages from the closed state. Excellent restart valve characteristics. In addition, a single sheet member may be used to improve the restart valve characteristics, and the two-stage structure of the float as described in the prior art is unnecessary, and the configuration can be simplified.

  As a preferred aspect of the present invention, the first connection passage has a first seal portion at an opening peripheral edge portion thereof, the float has a second seal portion at an upper portion thereof, and the seat member includes the valve A first seat portion that closes the first connection passage by being seated on the first seal portion and is provided on an opening peripheral portion of the lower portion of the valve body vent hole; And a second seat portion that closes the second connection passage by being seated on the second seal portion.

  Here, the second seal portion is a flat surface, and the second seat portion protrudes so as to surround an opening peripheral portion at the lower portion of the valve body vent hole and closely contacts the second seal portion. By adopting the configuration of the part, high sealing performance can be obtained with a simple 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.

(1) Schematic configuration of 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 shut-off valve 10 operates to automatically stop the fueling gun when the fuel in the fuel tank FT rises to the first fuel liquid level FL1 (full tank liquid level) during refueling, and the first fuel liquid level. The fuel is supplied over FL1 and closed when the second fuel liquid level FL2 (fully closed liquid level) is exceeded, and the outflow of fuel to the outside is regulated.

 The fuel tank FT includes a tank upper wall FTa whose surface is formed of a composite resin material containing polyethylene, and a mounting hole FTc is formed in the tank upper wall FTa. The fuel cutoff valve 10 is attached to the tank upper wall FTa in a state of entering the attachment hole FTc. The fuel cutoff valve 10 includes a casing 20, a valve body mechanism 50 having a float 51 and a seat member 55, and a spring 60, and a canister (illustrated) by raising and lowering the float 51 according to the fuel level in the fuel tank FT. Open and close the connection path to (omitted).

(2) Configuration of Each Part of Fuel Shutoff Valve 10 Hereinafter, the configuration and operation of each part of the fuel cutoff valve 10 will be described.

(2) -1 Casing 20
The casing 20 includes a casing body 30, a bottom support plate 35, and a lid body 40. The casing body 30 and the bottom support plate 35 are made of a synthetic resin polyacetal or nylon having fuel oil resistance. The lid 40 is made of a composite material mainly composed of polyethylene.

  FIG. 2 is an exploded cross-sectional view of the fuel cutoff valve 10. The casing body 30 includes a ceiling wall portion 32 and a side wall 33 extending in a cylindrical shape downward from the ceiling wall portion 32, and a cup-shaped valve chamber 30 </ b> S surrounded by the ceiling wall portion 32 and the side wall 33. The lower part is made the lower opening 30a. An upper projecting portion 32 a is formed at the center of the ceiling wall portion 32 downward. A first connection passage 32b passes through the upper protrusion 32a, and the valve chamber 30S side of the first connection passage 32b is an annular first seal portion 32c.

 The side wall 33 includes a communication hole 33a for communicating the valve chamber 30S and the fuel tank FT, an engagement hole 33b for attaching the bottom support plate 35 to the lower portion thereof, and a flange portion 33c for attaching the lid body 40 to the upper portion thereof. And. The bottom support plate 35 is a member that closes a part of the lower opening 30a of the casing body 30, and an engagement claw 35a formed on the outer periphery of the bottom support plate 35 engages with the engagement hole 33b. Mounted at the bottom of the. A communication hole 35 b for communicating with the valve chamber 30 </ b> S is formed at the center of the bottom support plate 35.

  The lid body 40 is formed on the lid body 41, a tube part 42 protruding in an L shape from the center to the top of the lid body 41, a flange 43 formed on the outer periphery of the lid body 41, and a lower surface of the lid body 41. And a welding surface 44, which are integrally formed. The tube portion 42 is formed with a tube passage 42a. One end of the tube passage 42a is connected to the first connection passage 32b of the casing body 30, and the other end is connected to the canister side. ing. Further, an annular welded portion 43 a that is welded to the tank upper wall FTa of the fuel tank FT is formed at the lower end portion of the flange 43. The welding surface 44 is formed so as to be welded to the flange portion 33c of the casing body 30, and for example, maleic acid-modified polyethylene is laminated by two-color molding or the like. The modified polyethylene has a heat-welding property to both polyacetal and polyethylene, and joins the lid body 40 and the casing body 30.

(2) -2 Valve body mechanism 50
The valve body mechanism 50 includes a float 51 and a seat member 55 mounted on the top of the float 51. The float 51 is formed in a container shape including an upper wall portion 52 and a cylindrical side wall portion 53 formed downward from the outer periphery of the upper wall portion 52, and the inner space generates buoyancy. Buoyancy chamber 51S. A plurality of guide protrusions 51 a are formed on the outer peripheral portion of the float 51 in the vertical direction. A spring 60 is disposed in the buoyancy chamber 51 </ b> S of the float 51. The spring 60 urges the float 51 upward by being interposed between one end of the float 51 and the upper surface of the bottom support plate 35.

  The float 51 includes a support portion 54 that supports the sheet member 55 on the top of the float 51. FIG. 3 is an enlarged cross-sectional view showing the vicinity of the support portion 54 and the sheet member 55. The support portion 54 is a chevron-shaped projecting portion provided with a conical second seal portion 54a on the upper surface so as to form the float upper chamber 55S, and the lower end of the support portion is an annular recess. A portion 54b is provided. FIG. 4 is a top view of the float 51. At the upper part of the float 51, a ventilation groove 54d for communicating the float upper chamber 55S surrounded by the seat member 55 to the valve chamber 30S of the seat member 55 is formed. That is, the ventilation grooves 54d are formed radially at four positions at intervals of 90 ° from the central axis of the support portion 54, and as shown in FIG. 3, go around the support lower portion 54b from the side of the support portion 54. Further, a radial direction is formed on the upper wall 52 of the float 51.

The sheet member 55 is formed in a cup shape that opens downward from a flexible material (rubber material, thermoplastic elastomer, etc.), that is, a sheet surface portion 55a, a side wall portion 55b, and an attachment portion 55c. And is attached to the upper portion of the float 51 in a state where the support portion 54 is disposed so as to enter the float upper chamber 55S. The seat surface portion 55a includes a first seat portion 56a that is attached to and detached from the first seal portion 32c. In the seat surface portion 55a, the first seat portion 56a is seated on the first seal portion 32c when the float 51 rises (see FIG. 5), and the first seat portion 56a becomes the first seal portion when the float 51 rises. When pushed by 32c, the sheet member 55 is formed so as to be elastically deformed as a whole (see FIG. 6). In addition, since the sheet member 55 is elastically deformed throughout and the stress is dispersed, it is excellent in durability. A valve body vent hole 57a is formed at the center of the seat surface portion 55a. A second seat portion 57b is formed at the lower end of the valve body vent hole 57a. The second seat portion 57b is formed so as to open and close the valve body vent hole 57a by being attached to and detached from the second seal portion 54a of the support portion 54.
The valve body vent 57a, the float upper chamber 55S, and the vent groove 54d constitute a second connection passage 58 connected from the valve chamber 30S to the first connection passage 32b.

(3) Operation of the fuel cutoff valve 10 Next, the opening / closing operation of the fuel cutoff valve 10 will be described. In FIG. 1, when fuel is supplied to the fuel tank FT, the fuel vapor accumulated in the upper part of the fuel tank FT as the fuel liquid level in the fuel tank FT rises is connected to the communication hole 33 a of the casing body 30, the valve chamber. 30S, the first connection passage 32b, and the tube passage 42a are escaped to the canister side. When the fuel level in the fuel tank FT reaches the predetermined first fuel level FL1, the fuel flows into the valve chamber 30S through the communication hole 35b of the bottom support plate 35. As a result, the float 51 rises when the former exceeds the latter due to the balance between the buoyancy of the float 51 and the upward force due to the load of the spring 60 and the downward force due to the weight of the float 51 and the seat member 55. As shown in FIG. 5, the first seat portion 56a of the seat member 55 is seated on the first seal portion 32c and closes a part of the first connection passage 32b.

  At this time, the second seat portion 57b of the seat member 55 is not seated on the second seal portion 54a, and the valve body vent hole 57a is kept open, that is, the second connection passage 58 is The first connection passage 32b and the valve chamber 30S are connected through the valve body vent 57a, the float upper chamber 55S, and the vent groove 54d. Therefore, the fuel tank FT communicates with the canister side through the first connection passage 32 b and the second connection passage 58. In this state, the second connection passage 58 is a throttle portion in which the flow passage area of the first connection passage 32b is narrowed, so that the tank internal pressure increases. This increase in tank internal pressure is detected by the fuel gun, and an auto-stop that stops the fuel supply of the fuel gun is activated. Thus, even when a part of the first connection passage 32b is closed when the fuel level in the fuel tank FT reaches the first fuel level FL1, the second connection passage 58 is secured. Therefore, the internal pressure of the tank does not rise suddenly, and the fuel does not blow back from the fuel filler port. As described above, when fuel is supplied to the fuel tank FT, the fuel vapor is allowed to escape from the fuel tank FT and the fuel can be prevented from flowing out from the fuel supply port.

  When the fuel level further reaches the second fuel level FL2 and the buoyancy of the float 51 increases, the seat member 55 is pushed by the first seal portion 32c as shown in FIG. The second sheet portion 57b is elastically deformed so as to bend toward the second seal portion 54a. Then, the second seat portion 57b is seated on the second seal portion 54a, and the valve body vent hole 57a is closed. As a result, the second connection passage 58 connected to the first connection passage 32b is closed and the inside of the fuel tank FT is sealed against the canister side, so that the tank internal pressure further rises and the fuel supply by the fuel supply gun is performed. Stops.

  Therefore, according to the fuel cutoff valve 10, the fuel tank FT is closed with respect to the canister side in two stages during refueling. Therefore, even if the fuel level reaches the first fuel level FL1, which is almost full. When the fuel pressure level reaches the second fuel liquid level FL2, which is a fully closed liquid level, fuel can be prevented from being blown back from the fuel filler port. Refueling with a gun can be stopped.

  On the other hand, when the fuel in the fuel tank FT is consumed and the fuel level is lowered, the float 51 reduces its buoyancy. In the state of FIG. 6, the pressure receiving area of the valve body vent hole 57 a is smaller than the pressure receiving area of the first connection passage 32 b, so that the force received by the seat member 55 in the valve closing direction is small, and the seat member 55 A force that lowers the float 51 is generated by the elastic force. Therefore, the seat member 55 quickly opens the valve body vent hole 57a. The pressure in the float upper chamber 55S surrounded by the seat member 55 due to the communication of the valve body vent hole 57a becomes the same pressure as the vicinity of the first connection passage 32b through the valve body vent hole 57a. As the pressure difference is reduced in this manner, the force with which the sheet member 55 is brought into close contact with the first seal portion 32c is weakened, so that the sheet member 55 is smoothly lowered. In this manner, the seat member 55 functions to promote the improvement of the restart valve characteristic that smoothly opens the valve body mechanism 50.

  The configuration of the fuel cutoff valve 10 of the above embodiment has the following effects.

(4) -1 The fuel shut-off valve 10 according to the above embodiment is seated at different fuel liquid levels because the seat member 55 including the first seat portion 56a and the second seat portion 57b is flexible. Thus, the first connection passage 32b and the second connection passage 58 can be configured to be sequentially closed, and there is no need to use a two-stage float or use a plurality of springs as described in the prior art. The structure is simple, the assembly process is simplified, and the adjustment of the spring load is not necessary.

(4) -2 When the fuel liquid level in the fuel tank FT is lowered, the seat member 55 applies an elastic force that lowers the float 51 by the curved elastic deformation, so that the float 51 is quickly lowered to the second position. Since the valve body vent 57a constituting a part of the connection passage 58 is opened, the restart valve characteristic for smoothly performing the valve opening operation for opening the first connection passage 32b from the closed state can be improved. In addition, in this embodiment, one seat member 55 may be used to improve the restart valve characteristic, and the two-stage structure of the float as described in the prior art is unnecessary, and the configuration can be simplified. .

  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.

(5) -1 FIGS. 7 and 8 are sectional views showing the upper part of the fuel cutoff valve according to the second embodiment. The second embodiment is characterized in that the second seal portion 54Ba of the support portion 54B of the float 51B is a flat surface. A second seat portion 57Bb protrudes downward from the periphery of the lower end opening of the valve body vent hole 57Ba of the seat member 55B.

  When the fuel level reaches the first fuel level FL1, the seat member 55B is seated on the first seal portion 32c, closes a part of the first connection passage 32b, and activates the fuel gun auto-stop. At this time, the second seat portion 57Bb of the seat member 55B is not seated on the second seal portion 54Ba and the inside of the fuel tank FT is connected to the outside through the second connection passage 58B. Can be performed. When the fuel level reaches the second fuel level FL2 due to supercharging, as shown in FIG. 8, the seat member 55B is pushed by the first seal portion 32c and the second seat portion 57Bb is moved downward. It bends down and sits on the second seal portion 54Ba. Thereby, the valve body ventilation hole 57Ba which comprises the 2nd connection channel | path 58B is closed, and the oil supply by an oil supply gun can be stopped.

(5) -2 The sheet member can take various shapes such as a hemisphere as long as the two seal portions are closed in stages and the float upper chamber is formed. In addition, slits may be formed radially from the center of the sheet surface portion of the sheet member, which makes it easier to dent the sheet surface portion.

(5) -3 In the above embodiment, the sheet member surrounded by the sheet surface portion and the side wall portion is configured to bend to the whole. However, the present invention is not limited to this, and a part of the thickness of the sheet member is changed. The sheet surface portion may be configured to be elastically deformed partly, for example, the thickness of the sheet surface portion is made thinner than the side wall portion so that the sheet surface portion is recessed, or the thickness of the sheet surface portion is heated from the side wall portion. However, the side wall portion may be elastically deformed so as to greatly expand in the radial direction while maintaining a flat surface.

(5) -4 The fuel cut-off valve according to the above embodiment has been described with respect to the structure that is welded to the upper surface of the tank upper wall of the fuel tank, but is not limited thereto, and is directly welded to the inner surface of the tank upper wall. The structure which fixes to a tank upper wall via the attachment member of may be sufficient.

It is sectional drawing which shows the fuel cutoff valve attached to the upper part of the fuel tank of the motor vehicle concerning the 1st Example of this invention. It is sectional drawing which decomposed | disassembled the fuel cutoff valve. It is sectional drawing which expands and shows the upper part of a float and the vicinity of a sheet | seat member. It is a top view of a float. It is explanatory drawing explaining operation | movement of a fuel cutoff valve. It is explanatory drawing explaining the operation | movement following FIG. It is sectional drawing which shows the upper part of the fuel cutoff valve concerning a 2nd Example. It is explanatory drawing explaining operation | movement of the fuel cutoff valve concerning a 2nd Example. It is sectional drawing which shows the fuel cutoff valve with which the upper part of the conventional fuel tank was mounted | worn.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fuel cutoff valve 20 ... Casing 30 ... Casing main body 30S ... Valve chamber 30a ... Lower opening 32 ... Ceiling wall part 32a ... Upper protrusion part 32b ... 1st 32c ... first seal part 33 ... side wall 33a ... communication hole 33b ... engagement hole 33c ... flange part 35 ... bottom support plate 35a ... engagement claw 35b ... Communication hole 40 ... Lid 41 ... Lid main body 42 ... Tube body 42a ... Tube passage 43 ... Flange 43a ... Annular weld 44 ... Weld surface 50 ... Valve body mechanism 51 ... Float 51B ... Float 51S ... Buoyancy chamber 51a ... Guide ridge 52 ... Upper wall part 53 ... Side wall part 54 ... Support part 54B ... support part 54a ... second seal part 54Ba ... second seal part 54b ... support lower end part 54d ... ventilation groove 55 ... sheet member 55B ... sheet member 55S. .. Float upper chamber 55a ... Sheet surface part 55Ba ... Sheet surface Part 55b ... Side wall part 55c ... Mounting part 56a ... First seat part 57a ... Valve body vent hole 57Ba ... Valve body vent hole 57b ... Second seat part 57Bb .. Second seat part 58 ... second connection passage 58B ... second connection passage 60 ... spring FT ... fuel tank FL1 ... first fuel liquid level FL2 ... second Fuel level of 2 FTa ... Tank upper wall FTc ... Mounting hole

Claims (3)

A fuel cutoff valve that is mounted on the upper part of the fuel tank (FT) and cuts off communication between the inside and outside of the fuel tank (FT)
A casing (20) having a valve chamber (30S) communicating with the fuel tank (FT);
A float (51) which is housed in the valve chamber (30S) and moves up and down in accordance with the fuel level in the fuel tank (FT), and is formed of a flexible material and is formed above the float (51). A valve body mechanism (50) having a seat member (55) mounted to form a float upper chamber (55S);
A connection passage that connects the valve chamber (30S) and the outside and is opened and closed by raising and lowering the float (51);
With
The seat member (55) has a valve body vent hole (57a) penetratingly connecting the float upper chamber (55S) and the valve chamber (30S),
The connection passage is connected to the first connection passage (32b) provided in the upper portion of the casing (20) and connecting the valve chamber (30S) to the outside, and the first connection passage (32b). A second connection passage (58) having a passage area smaller than that of the first connection passage (32b) and having the valve body vent hole (57a) and the float upper chamber (55S) as a route;
When the fuel level rises to the first fuel level (FL1), the second connection passage (58) is maintained in an open state and the first connection passage is provided by the seat member (55). (32b) is closed,
When the fuel liquid level rises to a second fuel liquid level (FL2) higher than the first fuel liquid level (FL1), the seat member (55) is elastically deformed and the upper part of the float (51). The second connection passage (58) is closed by being in close contact with
A fuel shut-off valve characterized by The fuel cutoff valve according to claim 1,
The first connection passage (32b) has a first seal portion (32c) at the periphery of the opening,
The float (51) has a second seal portion (54a) at the top thereof,
The seat member (55) is provided at the opening peripheral edge of the upper part of the valve body vent hole (57a) and is seated on the first seal portion (32c) to close the first connection passage (32b). The second connection passage (58) is formed by seating on the first seal portion (56a) and the second seal portion (54a) provided at the opening periphery of the lower portion of the valve body vent hole (57a). A fuel cutoff valve having a second seat portion (57b) for closing. The fuel cutoff valve according to claim 2,
The second seal portion (54Ba) is a flat surface, and the second seat portion (57Bb) is provided so as to surround the opening peripheral portion at the lower portion of the valve body vent hole (57Ba) and the second seal portion (54Ba). A fuel shut-off valve that is an annular protrusion that is in close contact with the seal portion (54Ba).

Images