JP2008232113A - Fuel cut-off valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cut-off valve 10 capable of flowing a large flow rate of fuel even if the passage area of a connecting passage 31c is reduced. <P>SOLUTION: The fuel cut-off valve 10 is provided with a casing 20 and a float 51. The casing 20 is provided with a casing main body 30 forming a valve chamber 30S establishing communication between a connection passage 31c and an inside of a fuel tank FT, and a cover body 40 including a pipe passage 43a connected to the connection passage 31. The casing 20 is provided with a connection part 33 formed at an upper part of the casing main body 30 and having the connection passage 31c formed through the same, a connected part 42 connected to the connection part 33, and a seal member SR put between the connection part 33 and the connected part 42. A pipe passage 43a has a straight passage 43b arranged in a horizontal direction and a curved passage 43c having roughly same passage area as the connection passage 31c. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel cutoff valve that is attached to an upper portion of a fuel tank and connects the inside and outside of the fuel tank.

  Conventionally, as a fuel shut-off valve of this type, the technique of Patent Document 1 is known. FIG. 7 is a sectional view showing a fuel cutoff valve 100 according to the prior art. The fuel shut-off valve 100 is mounted on the upper part of the fuel tank FT, and a casing 104 provided with a connection passage 102 connected to the outside (canister) in the upper part thereof, and the valve chamber 106 of the casing 104 in the valve chamber 106 depending on the fuel liquid level. And a float 108 that raises and lowers buoyancy. At the time of refueling, the ventilation between the inside and outside of the fuel tank FT is ensured, and the float 108 rises due to the increase in the buoyancy due to the increase in the fuel level in the fuel tank FT, thereby closing the connection passage 102 to the outside of the fuel. Prevents outflow.

  In the conventional fuel cutoff valve 100, the connection passage 102 is formed through the protrusion 110 at the top of the casing 104 and the upper end of the protrusion 110 is formed into a taper 112 so that the fuel vapor flows smoothly into the pipe passage 114. Is formed. However, the fuel vapor flowing out of the connection passage 102 flows to the pipe passage 114 through the connection space 116 that is widened by the taper 112 with respect to the pipe passage 114. It has been found by the present inventor that such a connection space 116 is larger than the width of the connection passage 102, thereby generating a turbulent flow and increasing a ventilation resistance.

JP 2000-266208 A

  An object of the present invention is to provide a fuel cutoff valve capable of flowing a large flow rate even if the passage area of the connection passage is reduced, in view of solving the problems of the conventional technology.

The present invention made to solve the problems
In 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 inside and outside of the fuel tank so as to cut off communication between the fuel tank and the outside.
A casing body provided with the connection passage in the vertical direction and forming a valve chamber communicating the connection passage with the inside of the fuel tank, and a pipe passage mounted on the casing body and connected to the connection passage. A casing having a lid,
A float that is housed in the valve chamber and opens and closes according to the fuel level in the fuel tank to open and close the opening on the valve chamber side of the connection passage;
With
The casing is connected to the connection passage by being formed at the upper portion of the casing body and penetrating the connection passage, and formed at the lower portion of the lid and being fitted to the connection portion. A connected portion having a pipe passage, and a seal member interposed between the connected portion and the connected portion,
The pipe passage has a straight passage arranged in a horizontal direction, and a curved passage having a passage area substantially the same as the connection passage,
The connecting portion includes a lower fitting protrusion protruding from the upper portion of the casing body, an upper fitting protrusion protruding from the upper portion of the lower fitting protrusion and having a smaller diameter than the lower fitting protrusion, and a lower fitting protrusion. And an annular stepped portion that holds the sealing member formed between the upper fitting protrusion and
The connected portion positions a lower fitting hole that fits into the lower fitting projection, an upper fitting hole that fits into the upper fitting projection, and an upper end of the upper fitting projection, and the connection A positioning protrusion formed so that the passage and the curved passage are continuous surfaces;
It is characterized by having.

  When fuel is supplied to a fuel tank using the fuel cutoff valve according to the present invention and reaches a predetermined liquid level in the fuel tank, the float rises by buoyancy due to the fuel flowing into the valve chamber. As the float rises, the valve portion at the top of the float closes the connection passage, thereby blocking the fuel tank from the outside and preventing the fuel from flowing out from the fuel tank.

  In the fuel shut-off valve according to the present invention, the fuel vapor in the fuel tank is bent from the valve passage from the connecting passage arranged in the vertical direction to the curved passage of the pipe passage, and through the straight passage arranged in the horizontal direction. It flows to the outside. Since the curved passages of the connection passage and the tube passage are formed with substantially the same passage area, there are few turbulent flows that hinder the flow, and the pressure loss is small. Therefore, even if the connection passage has a small passage area, a large flow rate can flow, and the height of the connection passage of the fuel shut-off valve is reduced, contributing to flattening of the tank device when attached to the fuel tank. Can do.

  In addition, the positioning protrusion formed on the connected portion of the lid body acts as a positioning at the upper end of the connecting portion, and acts so as to reduce the pressure loss by making the connecting passage and the curved passage of the pipe passage continuous. To do. Further, in the case of resin injection molding of the lid, generally, two slide molds are inserted into the mold cavity as means for forming the lower fitting hole and the upper fitting hole of the connected portion and the pipe passage. It is done by. The two slide molds have a gap between them in order to avoid colliding with each other during insertion. Such a gap is filled with resin, but a portion formed by this resin is effectively used as a positioning protrusion.

  Furthermore, as a suitable connection passage of the present invention, it is possible to adopt a configuration including a small diameter passage connected to the valve chamber and a large diameter passage connecting the small diameter passage and the curved passage. With this configuration, among the connection passages, the small-diameter passage can reduce the passage area of the opening and reduce the force in the valve closing direction of the valve portion, so that excellent restart valve characteristics can be obtained, and the large-diameter passage can be obtained. Since the passage has a passage area larger than that of the small-diameter passage, the passage acts as a liquid pool, so that the liquid fuel flowing out from the valve chamber to the connection passage stays here and can be prevented from flowing out.

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 an embodiment of the present invention. 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 cutoff valve 10 regulates the flow of fuel in the fuel tank FT to the canister when the vehicle is tilted or swings.

(2) Configuration of Each Part of Fuel Shutoff Valve 10 The fuel cutoff valve 10 includes a casing 20, a float mechanism 50, and a spring 70 as main components. The casing 20 includes a casing main body 30, a bottom plate 35, and a lid body 40. A space surrounded by the casing main body 30 and the bottom plate 35 is a valve chamber 30S, and the valve chamber 30S is supported by a spring 70. The float mechanism 50 is accommodated.

  FIG. 2 is an exploded cross-sectional view of the fuel cutoff valve 10. The casing body 30 has a cup shape surrounded by a ceiling wall portion 31 and a side wall portion 32, and a lower portion thereof is an opening 30a. At the center of the ceiling wall portion 31, there is formed a passage forming protrusion 31a projecting downward, and the tip of the passage forming protrusion 31a is a seal portion 31b. The side wall portion 32 is formed with a vent hole 32a for connecting the inside of the fuel tank FT and the valve chamber 30S, and an engagement hole 32b for attaching the bottom plate 35 is formed.

  3 is a cross-sectional view showing the upper part of the casing 20, and FIG. 4 is a cross-sectional view showing the upper part of the casing 20 in an exploded manner. A connecting portion 33 projects upward from the center of the ceiling wall portion 31. The connecting portion 33 includes a lower fitting protrusion 33a protruding from the upper portion of the ceiling wall portion 31, an upper fitting protrusion 33b protruding from the upper portion of the lower fitting protrusion 33a and having a smaller diameter than the lower fitting protrusion 33a, and a lower portion An annular step 33c is formed between the fitting protrusion 33a and the upper fitting protrusion 33b and holds the seal member SR. A seal member SR is held on the annular step portion 33c. A connection passage 31c passes through the connection portion 33 so as to be concentric with the passage formation protrusion 31a. That is, the connection passage 31c includes a small diameter passage 31d that penetrates the passage formation protrusion 31a and a large diameter passage 31e that penetrates the connection portion 33 and is connected to the upper portion of the small diameter passage 31d.

  Returning to FIG. 2, the bottom plate 35 is a member that closes the opening 30 a of the casing body 30, and an engagement claw 35 a formed on the outer peripheral portion of the bottom plate 35 engages with the engagement hole 32 b of the casing body 30. It mounts | wears so that the opening 30a of 30 may be closed. On the upper surface of the bottom plate 35, a spring support portion 35 c for supporting the communication hole 35 b and the lower end of the spring 70 is formed.

  The lid 40 is formed on the outer periphery of the lid main body 41, the connected portion 42 formed at the lower center of the lid main body 41, the tubular body 43 projecting laterally from the center of the lid main body 41, and the lid main body 41. The flange 44 and the support part 45 are provided, and these are integrally formed. 3 and 4, the connected portion 42 includes a lower fitting hole 42a that fits into the lower fitting projection 33a, an upper fitting hole 42b that fits into the upper fitting projection 33b, and a positioning projection. 42c and is fitted to the connecting portion 33. A tube passage 43a is formed in the tube body portion 43. The tube passage 43a includes a straight passage 43b disposed in the horizontal direction and a curved passage 43c that connects the direct passage 43b and the connection passage 31c. . The passage area S1 of the curved passage 43c is formed substantially the same as the passage area S2 of the connection passage 31c.

  The support portion 45 shown in FIG. 2 is a cylindrical body that is formed at the lower portion of the lid main body 41 and that fits and supports the upper portion of the casing main body 30. An engagement hole 45 a is formed in the support portion 45. The engagement hole 45 a is engaged with an engagement claw 32 c formed in the side wall portion 32 of the casing body 30, so that the lid body 40 holds the casing body 30. Further, an outer welded portion 44 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 44.

  The float mechanism 50 includes a float 51 and a conical valve portion 55 protruding from the top of the float 51. The float 51 is configured in a container shape including an upper wall portion 51a and a cylindrical side wall 51b formed downward from the outer periphery of the upper wall portion 51a, and the buoyancy for generating buoyancy in the inner space. It is chamber 51S. A guide protrusion 51 c is formed on the outer periphery of the float 51. The guide protrusions 51c are provided on the side wall 51b of the float 51 so as to protrude in eight ribs at equal intervals in the circumferential direction and in a rib shape in the vertical direction. A spring 70 is disposed in the buoyancy chamber 51 </ b> S of the float 51. The spring 70 urges the float 51 upward by being interposed between one end of the float 51 and the upper surface of the bottom plate 35.

  In order to assemble the fuel cutoff valve 10, the float 51 and the spring 70 are accommodated in the valve chamber 30 </ b> S of the casing body 30, and the lower end of the spring 70 is aligned with the spring support portion 35 c of the bottom plate 35. The bottom plate 35 is attached to the casing body 30 by engaging the engaging claws 35 a with the engaging holes 32 b of the side wall portion 32. Further, the seal member SR is inserted into the connection portion 33 and held on the annular step portion 33c. In this state, the support portion 45 is fitted to the upper portion of the casing body 30, and the connection portion 33 is attached to the lid body 40. It fits into the connected part 42. At this time, the engagement hole 45 a of the support portion 45 engages with the engagement claw 32 c of the casing body 30. Thereby, the cover body 40 and the casing main body 30 are integrated.

(3) Operation of the fuel cutoff valve 10 Next, the operation of the fuel cutoff valve 10 will be described. In FIG. 1, when the fuel level in the fuel tank FT rises due to vehicle inclination or the like, the fuel vapor accumulated in the upper part of the fuel tank FT enters the valve chamber 30S through the communication hole 35b and the vent hole 32a. The valve chamber 30S is released to the canister side through the connection passage 31c and the pipe passage 43a. As the fuel level in the fuel tank FT rises, the fuel flows into the valve chamber 30S through the communication hole 35b. When the fuel level reaches a predetermined level, 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 70 and the downward force due to the weight of the float 51. Sometimes the float 51 rises. As a result, when the vehicle is inclined, the fuel vapor can escape from the fuel tank FT and the fuel can be prevented from flowing out of the fuel tank FT. On the other hand, when the fuel level in the fuel tank FT decreases and the fuel in the valve chamber 30S is discharged from the communication hole 35b or the like, the float 51 reduces its buoyancy and receives a downward force, 55 leaves the seal portion 31b and opens the connection passage 31c.

(4) Operation and effect of the embodiment The configuration of the fuel cutoff valve 10 of the above embodiment provides the following effects.
(4) -1 As shown in FIG. 1, when the fuel level in the fuel tank FT rises due to refueling, the fuel vapor in the fuel tank flows from the valve chamber 30S to the outside through the connection passage 31c and the pipe passage 43a. As shown in FIG. 3, the connecting passage 31c is formed to have substantially the same passage area as the curved passage 43c, so there is little turbulent flow that hinders the flow and the pressure loss is small.
Next, the effect of the shape of the passage of the connection passage 31c on the increase of the flow rate was examined. FIG. 5 is an explanatory diagram for explaining the relationship between the flow rate and the tank internal pressure when the fuel cutoff valve is opened. In FIG. 5, the vertical axis indicates the tank internal pressure which is a differential pressure with respect to the pressure (outside air) of the pipe passage 43a in a state where the fuel cutoff valve 10 is attached to the upper part of the fuel tank, and the horizontal axis indicates the tank internal pressure. The flow rate which flows out from pipe passage 43a is shown. Here, the solid line indicates the present embodiment, and the broken line corresponds to a comparative example (conventional example). From FIG. 5, it was found that the flow rate of the present example was larger over the entire range of the tank internal pressure than the conventional example. In particular, as a target specification of the fuel cutoff valve 10, 35 L / min at a pressure of 9.8 kPa could be achieved.

(4) -2 The connection passage 31c has a small pressure loss, and can flow a large flow rate even in a small passage area. Therefore, the connection passage 31c and the pipe passage 43a can be narrowed, which contributes to the miniaturization of the fuel cutoff valve 10, and can contribute to the flattening of the tank device when attached to the fuel tank.

(4) -3 The positioning protrusion 42c formed on the connected portion 42 of the lid body 40 functions as a member for positioning the upper end of the connecting portion 33, and continuously connects the connecting passage 31c and the curved passage 43c of the tube passage 43a. And acts to reduce pressure loss. FIG. 6 is an explanatory diagram for explaining a process of injection molding the lid body 40. As shown in FIG. 6, in the case of resin injection molding of the lid 40, the lower fitting hole 42a and the upper fitting hole 42b of the connected portion 42 and the pipe passage 43a are formed in the cavity CT of the mold MD. Further, the first slide type SM1 and the second slide type SM2 are respectively inserted into the cavities CT. At this time, the front end of the second slide type SM2 moves by a distance La along the end portion of the first slide type SM1 before being fitted to the first slide type SM1, but the end portion of the first slide type SM1 In order to avoid hitting, a gap Gp is provided between them. Such a gap Gp is filled with resin, but a portion formed by this resin is effectively utilized as the positioning protrusion 42c.

(4) -4 As shown in FIGS. 3 and 4, the connection passage 31c includes a small diameter passage 31d connected to the valve chamber 30S, and a large diameter passage 31e connecting the small diameter passage 31d and the curved passage 43c. It has. The small-diameter passage 31d of the connection passage 31c is an opening that closes the valve portion 55 of the float 51, has a small area, and reduces the force in the valve closing direction of the valve portion 55, so that excellent restart valve characteristics can be obtained. The large-diameter passage 31e acts as a liquid reservoir having a larger capacity than the small-diameter passage 31d, and the liquid fuel flowing out from the valve chamber 30S to the connection passage 31c stays here and can be prevented from flowing out.
The present invention is not limited to the above-described embodiments, and can be implemented in various modes without departing from the scope of the invention.

It is sectional drawing which shows the fuel cutoff valve 10 attached to the upper part of the fuel tank FT of the motor vehicle concerning one Example of this invention. 3 is an exploded cross-sectional view of the fuel cutoff valve 10. FIG. FIG. 3 is a cross-sectional view showing the upper part of the casing 20. FIG. 3 is an exploded cross-sectional view showing an upper part of a casing 20. It is explanatory drawing explaining the relationship between the flow volume at the time of valve opening of a fuel cutoff valve, and a tank internal pressure. It is explanatory drawing explaining the process of injection-molding the cover body. It is sectional drawing which shows the fuel cutoff valve 100 concerning a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fuel cutoff valve 20 ... Casing 30 ... Casing main body 30S ... Valve chamber 30a ... Opening 31 ... Ceiling wall part 31a ... Passage formation protrusion 31b ... Sealing part 31c ... Connection passage 31d ... Small diameter passage 31e ... Large diameter passage 32 ... Side wall Portion 32a ... Vent hole 32b ... engagement hole 32c ... engagement claw 33 ... connection portion 33a ... lower fitting projection 33b ... upper fitting projection 33c ... annular step 35 ... bottom plate 35a ... engagement claw 35b ... communication hole 35c ... Spring support part 40 ... Lid body 41 ... Lid main body 42 ... Connected part 42a ... Lower fitting hole 42b ... Upper fitting hole 42c ... Positioning projection 43 ... Tube part 43a ... Pipe passage 43c ... Curved passage 44 ... Flange 44a ... Outer welding part 45 ... Supporting part 45a ... Engagement hole 50 ... Float mechanism 51 ... Float 51S ... Buoyancy chamber 51a ... Upper wall part 51b ... Side wall 51c ... Guide protrusion 5 ... valve portion 70 ... spring SR ... sealing member CT ... cavity FT ... Fuel tank FTa ... tank upper wall FTb ... mounting hole MD ... die SM1 ... first slide die SM2 ... second slide die

Claims (2)

A fuel cutoff valve that is mounted on the upper portion of the fuel tank (FT) and that opens and closes a connection passage (31c) that connects the inside of the fuel tank (FT) and the outside, thereby disconnecting the fuel tank (FT) from the outside. ,
The casing main body (30) in which the connection passage (31c) is provided in the vertical direction to form a valve chamber (30S) communicating the connection passage (31c) and the fuel tank (FT), and the casing main body (30 ), And a casing (20) having a lid (40) having a pipe passage (43a) connected to the connection passage (31c),
A float (51) which is housed in the valve chamber (30S) and opens and closes the opening of the connection passage (31c) on the valve chamber (30S) side by raising and lowering according to the fuel level in the fuel tank (FT). When,
With
The casing (20) is formed at the upper part of the casing body (30) and formed at the lower part of the lid (40) and the connecting part (33) passing through the connecting passage (31c). A connected portion (42) having a pipe passage (43a) connected to the connecting passage (31c) by being fitted to the connecting portion (33), the connecting portion (33), and the connected portion ( 42) and a sealing member (SR) interposed therebetween,
The pipe passage (43a) has a straight passage (43b) arranged in the horizontal direction and a curved passage (43c) having substantially the same passage area as the connection passage (31c),
The connecting portion (33) includes a lower fitting protrusion (33a) protruding from the upper portion of the casing body (30) and a lower fitting protrusion (33a) protruding from the upper portion of the lower fitting protrusion (33a). A smaller diameter upper fitting projection (33b) and an annular step (33c) formed between the lower fitting projection (33a) and the upper fitting projection (33b) and holding the sealing member (SR). )
The connected portion (42) includes a lower fitting hole (42a) that fits into the lower fitting projection (33a) and an upper fitting hole (42b) that fits into the upper fitting projection (33b). And a positioning protrusion (42c) formed so as to position the upper end of the upper fitting protrusion (33b) and make the connection passage (31c) and the curved passage (43c) continuous.
A fuel cutoff valve characterized by comprising: The fuel cutoff valve according to claim 1,
The connection passage (31c) includes a small diameter passage (31d) connected to the valve chamber (30S) and a large diameter passage (31e) connecting the small diameter passage (31d) and the curved passage (43c). Equipped with a fuel shut-off valve.

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