fuel shutoff valve

Abstract

A fuel cutoff valve capable of suppressing the surface pressure of the valve in contact with the valve seat. [Solution] The fuel cutoff valve comprises a cylindrical valve seat provided in a valve chamber, wherein the through hole is located within the valve seat when the valve seat and the through hole are viewed in the axial direction of the valve seat, and a valve provided in a position opposite the tip face of an extension portion, wherein the tip face of the valve seat is large enough to overlap the valve when the valve seat and the valve are viewed in the axial direction of the valve seat, and when the tip face of the extension portion presses against the valve, the valve elastically deforms so that the valve is in contact with the tip face of the valve seat around the entire circumference.

Description

[Technical Field]

[0001] The present disclosure relates to a fuel shutoff valve. [Background technology]

[0002] Patent Document 1 discloses a fuel cutoff valve to be installed in a fuel tank. This fuel cutoff valve has a case with a raw fuel inlet / outlet port at the bottom and a fuel evaporative gas outlet port at the top. A valve portion is formed at the top end of the case and a float valve is housed therein so that it can move up and down, with a valve seat opening fixed opposite the top of the valve portion. With this fuel cutoff valve, under normal conditions when the fuel level in the fuel tank is dropping, the float valve drops and fuel evaporative gas is discharged through the outlet port and the valve opening into a communication passage (outside the fuel tank). When the fuel level in the fuel tank rises to the fuel cutoff valve in a substantially horizontal position, the float valve rises and the valve portion closes the valve seat opening, preventing raw fuel from leaking into the communication passage (outside the fuel tank). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 09-151819 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the fuel cutoff valve disclosed in Patent Document 1, the outer diameter of the valve portion is small, so the surface pressure of the valve portion (valve) that blocks the valve seat opening becomes high, and if the fuel oil level in the fuel tank rises to the fuel cutoff valve in a substantially horizontal state, there is a risk that the valve portion (valve) will become stuck to the valve seat opening (valve seat).

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and an object of the present disclosure is to provide a fuel cutoff valve that can suppress the surface pressure of the valve that contacts the valve seat. [Means for solving the problem]

[0006] A fuel cutoff valve according to at least one embodiment of the present invention is a fuel cutoff valve installed in a fuel tank, and includes a housing in which a float chamber communicating with the inside of the fuel tank and a valve chamber communicating with the outside of the fuel tank are arranged adjacent to each other vertically, a partition wall separating the float chamber and the valve chamber, the partition wall having a through-hole penetrating from the float chamber to the valve chamber, a float having a floating body portion accommodated in the float chamber and an extension portion extending from the floating body portion through the through-hole to the float chamber, and a cylindrical valve seat provided in the valve chamber. a valve seat in which the through hole is located within the valve seat when the valve seat and the through hole are viewed in the axial direction of the valve seat; and a valve provided in a position opposite a tip end face of the extension portion of the valve chamber, the tip end face of the valve seat being sized so that the entire tip end face of the valve seat overlaps the valve when the valve seat and the valve are viewed in the axial direction of the valve seat, wherein when the tip end face of the extension portion presses the valve, the valve elastically deforms so that the valve is in contact with the entire circumference of the tip end face of the valve seat. [Effects of the Invention]

[0007] According to the fuel cutoff valve of the present disclosure, the surface pressure of the valve that contacts the valve seat can be suppressed. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a diagram illustrating a fuel tank and a charcoal canister. [Figure 2A] 1 is a cross-sectional view schematically showing the configuration of a fuel cutoff valve according to an embodiment, illustrating a state in which the fuel cutoff valve is open; [Figure 2B] 2B is a diagram showing a state in which the fuel cutoff valve shown in FIG. 2A is closed. FIG. [Figure 3A] FIG. 2C is a diagram showing an example of the valve shown in FIGS. 2A and 2B. [Figure 3B]3B is a diagram showing a state in which the valve shown in FIG. 3A is pressed and deformed by an extension portion. FIG. [Figure 4A] FIG. 3 is a diagram showing another example of the valve shown in FIGS. 2A and 2B. [Figure 4B] 4C is a diagram showing a state in which the valve shown in FIG. 4B is pressed and deformed by an extension portion. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of components described as embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the present invention.

[0010] As shown in Fig. 1, a fuel cutoff valve 1 according to this embodiment is a fuel cutoff valve installed in a fuel tank 3 mounted on a vehicle. The fuel cutoff valve 1 is connected to a charcoal canister 7 installed outside the fuel tank 3 via an evaporation pipe 5. The fuel cutoff valve 1 is installed on the top surface of the fuel tank 3, but is not limited to this. For example, the fuel cutoff valve 1 may be installed to the side of the fuel tank 3, away from the fuel tank 3.

[0011] [Configuration of fuel shutoff valve] As shown in FIGS. 2A and 2B, the fuel cutoff valve 1 according to the embodiment includes a housing 12, a partition wall 14, a float 16, a valve seat 18, and a valve 20.

[0012] The housing 12 is cylindrical, and a float chamber 22 and a valve chamber 24 are provided inside the housing 12, adjacent to each other vertically. The float chamber 22 is a space that communicates with the interior of the fuel tank 3 and is provided below the valve chamber 24. The float chamber 22 is a cylindrical space, and is provided inside the fuel tank 3, but is not limited to this. A communication port 28 is provided in the floor 26 of the float chamber 22, through which liquid fuel in the fuel tank 3 flows in and out, and a communication port 32 is provided in the wall 30 of the float chamber 22, through which air containing evaporated fuel in the fuel tank 3 flows in and out. As a result, liquid fuel in the fuel tank 3 flows in and out of the float chamber 22, and air containing evaporated fuel in the fuel tank 3 flows in and out of the float chamber 22. The valve chamber 24 is a space that communicates with the outside of the fuel tank 3 and is provided above the float chamber 22. The valve chamber 24 is, for example, a cylindrical space and is provided outside the fuel tank 3, but is not limited to this. A communication pipe 34 that communicates with the outside of the valve chamber 24 is connected to the valve chamber 24. The communication pipe 34 is connected to the charcoal canister 7 via an evaporation pipe 5, and air containing evaporated fuel flows into the charcoal canister 7.

[0013] The partition wall 14 separates the float chamber 22 and the valve chamber 24. The partition wall 14 according to this embodiment is located at the same position as the upper wall portion 4 of the fuel tank 3 in the height direction of the fuel tank 3, but may be located lower or higher than the upper wall portion 4 of the fuel tank 3. The partition wall 14 is provided with a through-hole 36 that penetrates from the float chamber 22 to the valve chamber 24. The through-hole 36 is a hole with a circular cross section, but may also be a hole with a polygonal cross section. The through-hole 36 is a straight hole with a uniform cross section from the float chamber 22 to the valve chamber 24, but may also be a tapered hole with a cross section that gradually decreases in size from the float chamber 22 to the valve chamber 24.

[0014] The float 16 has a floating body portion 38 and an extension portion 40. The floating body portion 38 is housed in the float chamber 22. The floating body portion 38 is intended to float the float 165 in the liquid fuel flowing in and out of the float chamber 22. For example, the floating body portion 38 may be cylindrical, with air sealed inside, but this is not limited to this. The extension portion 40 extends from the floating body portion 38 through the through hole 36 to the valve chamber 24. The extension portion 40 has a cross-section similar to that of the through hole 36 and includes a tapered portion 42 that gradually expands toward the floating body portion 38 beyond the size of the through hole 36. The extension portion 40 is not limited to having a cross-section similar to that of the through hole 36, but in this case, the tapered portion 42 is not necessary.

[0015] The valve seat 18 is cylindrical and provided in the valve chamber 24. When the valve seat 18 and the through hole 36 are viewed in the axial direction of the valve seat 18, the through hole 36 is located within the valve seat 18. The valve seat 18 is, for example, cylindrical, and when the valve seat 18 and the through hole 36 are viewed in the direction of the axis AX of the valve seat 18, the center of the through hole 36 is located at the center of the valve seat 18, but the center of the through hole 36 may be located at a position deviated from the center of the valve seat 18. The valve seat 18 is provided so as to be continuous with the partition wall 14, but may also be provided so as to be continuous with a wall portion 44 of the valve chamber 24.

[0016] The valve 20 is provided at a position facing the tip surface (pressure surface) 46 of the extension portion 40 of the valve chamber 24. The valve 20 is made of an elastomer material such as rubber. The valve 20 is sized so that the tip surface (seat surface) 48 of the valve seat 18 entirely overlaps the valve 20 when the valve seat 18 and the valve 20 are viewed in the direction of the axis AX of the valve seat 18. The valve 20 is, for example, disc-shaped, and when the valve seat 18 and the valve 20 are viewed in the direction of the axis AX of the valve seat 18, the center of the valve 20 is located at the center of the valve seat 18.

[0017] The valve 20 has a protrusion 52 housed in a recess 50 provided in the valve chamber 24. The protrusion 52 is movable up and down relative to the recess 50. The recess 50 is provided in a position facing the extension 40 of the valve chamber 24 so as to be recessed in the opposite direction from the extension 40. The recess 50 is provided in a protrusion 56 extending from the ceiling 54 of the valve chamber 24 toward the valve 20, but may also be provided in the ceiling 54 of the valve chamber 24. The protrusion 56 has a cylindrical shape that forms a circle when viewed in the direction of the axis AX of the valve seat 18, but this is not limited to this. Furthermore, by providing the protrusion 56 in the ceiling 54 of the valve chamber 24, the upper surface of the housing 12 may protrude. For example, the recess 50 has a cylindrical space, and when the valve 20 and the recess 50 are viewed in the direction of the axis AX of the valve seat 18, the center of the recess 50 is located at the center of the valve 20. The protrusion 52 is, for example, cylindrical, and is located at the center of the valve 20 when the valve 20 is viewed in the direction of the axis AX of the valve seat 18.

[0018] The valve 20 is supported by the ceiling 54 of the valve chamber 24 with the protrusion 52 housed in the recess 50. A spring 58 is attached between the inner peripheral surface of the recess 50 and the outer peripheral surface of the protrusion 52. The spring 58 is a compression spring (e.g., a compression coil spring), and when the protrusion 52 rises relative to the recess 50, the spring 58 contracts, and when the spring 58 returns to its original position, the protrusion 52 returns to its original position relative to the recess 50.

[0019] 2B , when the tip surface 46 of the extension 40 presses against the valve 20, the valve 20 elastically deforms so that the valve 20 comes into contact with the tip surface 48 of the valve seat 18 over the entire periphery. For example, when the tip surface 46 of the extension 40 presses against the valve 20, the convex portion 52 rises relative to the concave portion 50, and the valve 20 deforms so that the valve 20 comes into contact with the tip surface 48 of the valve seat 18 over the entire periphery. Furthermore, when the float 16 descends relative to the float chamber 22, the convex portion 52 descends to its original position relative to the concave portion 50, and the valve 20 returns to its original shape with the assistance of the elastic restoring force of the spring, the valve 20 separates from the tip surface 48 of the valve seat 18, and a gap (passage) is formed between the tip surface 48 of the valve seat 18 and the valve 20.

[0020] 3A , in the valve 20 according to this embodiment, when the recess 50 is viewed in the direction of the axis AX of the valve seat 18, a thin-walled portion 62 is provided around the entire periphery of the distal end surface 46 of the extension portion 40, at a position that is outer than the distal end surface 46 of the extension portion 40 and inner than the distal end surface 60 of the recess 50. The thin-walled portion 62 is provided on the surface of the valve 20 facing the extension portion 40, but may also be provided on the surface of the valve 20 facing the recess 50, or may be provided on both the surface of the valve 20 facing the extension portion 40 and the surface of the valve 20 facing the recess 50. When the thin-walled portion 62 is provided in this manner, as shown in FIG. 3B , when the distal end surface 46 of the extension portion 40 presses against the valve 20, the valve 20 is pushed against the inlet of the recess 50, and the valve 20 can be deformed so that it contacts the distal end surface 48 of the valve seat 18 around the entire periphery.

[0021] As shown in FIG. 4A , the housing 12 according to this embodiment has a cylindrical deformation assisting portion 64 that is provided around the entire circumference of the valve seat 18 at a position that overlaps with the valve 20 and is outside the valve seat 18 when the valve 20 is viewed in the direction of the axis AX of the valve seat 18. The deformation assisting portion 64 is cylindrical, and when the deformation assisting portion 64 and the recess 50 are viewed in the direction of the axis AX of the valve seat 18, the center of the deformation assisting portion 64 is located at the center of the recess 50. The deformation assisting portion 64 is provided so as to continue from the ceiling portion 54 of the valve chamber 24, but may also be provided so as to continue from the wall portion 44 of the valve chamber 24. When the deformation assisting portion 64 is provided in this manner in the valve chamber 24, as shown in FIG. 4B , when the tip surface 46 of the extension portion 40 presses against the valve 20, the valve 20 is supported by the deformation assisting portion 64, allowing the valve 20 to deform so as to contact the tip surface 48 of the valve seat 18 around the entire circumference.

[0022] [Fuel shutoff valve operation] 2A, when the liquid fuel level in the fuel tank 3 is lower than the fuel cutoff valve 1, air containing evaporated fuel in the fuel tank 3 flows from the communication ports 28, 32 provided in the floor 26 and wall 30 of the float chamber 22 of the fuel cutoff valve 1 through the float chamber 22, the through-hole 36, the valve seat 18, the valve chamber 24, and the communication pipe 34 to the outside of the fuel cutoff valve 1. Then, the air containing evaporated fuel flows from the communication pipe 34 of the fuel cutoff valve 1 through the evaporative pipe 5 to the charcoal canister 7.

[0023] Meanwhile, when the liquid fuel level in the fuel tank 3 becomes higher than the bottom surface of the fuel shutoff valve 1 and liquid fuel enters the float chamber 22 of the fuel shutoff valve 1, the float 16 floats on the liquid fuel and begins to rise. As the float 16 continues to rise and the extension 40 of the float 16 presses against the valve 20, the valve 20 deforms so that it contacts the entire periphery of the tip surface 48 of the valve seat 18. As a result, as shown in FIG. 2B , the gap (passage) between the valve seat 18 and the valve 20 is blocked, blocking the flow of air containing evaporated fuel and also blocking the flow of liquid fuel. This prevents the liquid fuel in the fuel tank 3 from flowing through the fuel shutoff valve 1 into the charcoal canister 7.

[0024] On the other hand, when the liquid fuel level in the fuel tank 3 falls below the predetermined position of the fuel shutoff valve 1, the float 16 begins to descend. As a result, the extension 40 of the float 16 that had been pressing against the valve 20 gradually descends, and the valve 20 gradually returns to its original shape, gradually separating from the valve seat 18. As a result, a gap (passage) opens between the valve seat 18 and the valve 20, as shown in Figure 2A, and the flow of air containing evaporated fuel resumes.

[0025] [Effect of fuel shutoff valve] According to the fuel cutoff valve 1 of the embodiment, when the tip surface 46 of the extension portion 40 presses against the valve 20, the valve 20 elastically deforms so that the valve 20 contacts the tip surface 48 of the valve seat 18 around the entire circumference, thereby suppressing the surface pressure of the valve 20 contacting the valve seat 18.

[0026] Furthermore, extension portion 40 has a cross section similar to that of through opening 36 and has tapered portion 42 that gradually expands beyond the size of through opening 36 toward floating portion 38, so that tapered portion 42 can close through opening 36. This makes it possible to prevent liquid fuel from leaking from inside fuel tank 3 through fuel shutoff valve 1 to the outside of fuel tank 3 even if the vehicle on which fuel tank 3 is mounted rolls over.

[0027] The present invention is not limited to the above-described embodiments, but also includes modifications to the above-described embodiments and appropriate combinations of these modifications. [Explanation of symbols]

[0028] 1 Fuel shutoff valve 3 fuel tanks 4 Upper wall 5 Evaporative pipe 7 Charcoal Canister 12. Case 14 Bulkhead 16 Float 18 Valve seat 20 valves 22 Float Chamber 24 Valve chamber 26 Floor 28 Connecting port 30 Wall 32 Connecting port 34 Communication pipe 36 Through hole 38 Floating body section 40 Stretching section 42 Tapered section 44 Wall 46 Tip surface (pressure surface) 48 Tip surface (seat surface) 50 recess 52 Convex part 54 Ceiling 56 Protrusion 58 Spring 60 Tip surface 62 Thin-walled section 64 Transformation support part AX Axis of the valve seat

Claims

1. A fuel shutoff valve installed in a fuel tank, a housing in which a float chamber communicating with the inside of the fuel tank and a valve chamber communicating with the outside of the fuel tank are arranged adjacent to each other vertically; a partition wall separating the float chamber and the valve chamber, the partition wall having a through-hole extending from the float chamber to the valve chamber; a float having a floating body portion accommodated in the float chamber and an extension portion extending from the floating body portion through the through hole into the float chamber; a cylindrical valve seat provided in the valve chamber, wherein the through hole is located within the valve seat when the valve seat and the through hole are viewed in the axial direction of the valve seat; a valve provided in a position facing a tip end surface of the extension portion of the valve chamber, the tip end surface of the valve seat being sized so that the entire tip end surface of the valve seat overlaps with the valve when the valve seat and the valve are viewed in the axial direction of the valve seat; Equipped with When the tip end surface of the extension portion presses the valve, the valve elastically deforms so that the valve contacts the tip end surface of the valve seat over the entire periphery. Fuel shutoff valve.

2. the housing has a recessed portion recessed in a direction opposite to the extension portion of the valve chamber at a position facing the extension portion, The valve has a protrusion that is accommodated in the recess.

2. The fuel shutoff valve of claim 1.

3. The fuel cutoff valve according to claim 2 , further comprising a spring mounted between an inner circumferential surface of the recess and an outer circumferential surface of the protrusion.

4. 4. The fuel cutoff valve according to claim 2, wherein the valve has a thin-walled portion provided around the entire circumference of the tip end surface of the extension portion, at a position that is outer than the tip end surface of the extension portion and inner than the tip end surface of the recessed portion when the extension portion and the recessed portion are viewed in the axial direction of the valve seat.

5. 4. The fuel cutoff valve according to claim 1, wherein the housing has a cylindrical deformation assisting portion that is provided around the entire circumference of the valve seat at a position that overlaps with the valve outside the valve seat when the valve seat and the valve are viewed in the axial direction of the valve seat.

6. The fuel cutoff valve according to claim 1 , wherein the extension portion has a tapered portion that gradually expands beyond the size of the through-hole toward the floating body portion.

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