Fuel tank valve device

Abstract

To provide a valve gear for a fuel tank enabling a filling-up restriction position to be set high.SOLUTION: A valve gear for a fuel tank 10 includes: a housing 15 having a partition wall 22 and an opening 25; and a float valve 19. The float valve 19 includes a lower member 40, an intermediate valve element 50 and an upper member 60. The lower member 40 has an attachment part 43, and a plurality of first projections 45 and second projections 47 are provided on the outer periphery of the lower member. The upper member 60 has first elastic engagement pieces 70 engaging with the first projections 45. The intermediate valve element 50 has second elastic engagement pieces 51 engaging with the second projections 47. An engagement surface of the second projection 47 with the second elastic engagement piece 51 is positioned within a range of an axial height of the first projection 46.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a valve device for a fuel tank that is attached to a fuel tank of an automobile or the like and used as a fuel outflow prevention valve, a full tank regulation valve, or the like.

Background Art

[0002] In a fuel tank of an automobile, there are installed a full tank regulation valve that prevents overfilling of fuel into the fuel tank so that the liquid level in the fuel tank does not rise above a preset full tank liquid level, and a fuel outflow prevention valve that prevents fuel in the fuel tank from leaking out when the automobile turns or tilts.

[0003] Generally, these valve devices have a structure including a housing having a partition wall with an opening and a valve chamber, and a float valve that is disposed in the valve chamber so as to be able to move up and down and opens and closes the opening. Also, when the float valve rises obliquely, the sealing performance with the opening decreases, so a structure in which an upper member that can swing above the float is provided is also adopted.

[0004] For example, in Patent Document 1 below, a housing is provided with a valve chamber communicating downward with a fuel tank and a ventilation chamber communicating upward with a fuel vapor discharge port via a partition wall, and an opening communicating the valve chamber and the ventilation chamber is provided in the partition wall. A valve device for a fuel tank including a float valve that is accommodated in the valve chamber so as to be able to move up and down and opens and closes the opening is disclosed.

[0005] The float valve is composed of a lower member forming a float body, an upper member that is assembled above the lower member so as to be able to move up and down and tilt by a predetermined distance with respect to the lower member, a seal member attached to the upper member, and an intermediate valve body that is attached to the lower member so as to be able to tilt and is disposed between the lower member and the upper member.

[0006] Furthermore, an upper member assembly section is provided above the lower member, and an annular projection, smaller in diameter than the upper member assembly section, is continuously provided from the upper center of this section. In addition, an engaging section is provided on the upper outer circumference of the upper member assembly section, and an annular projection is provided on the upper outer circumference of the intermediate valve body assembly section.

[0007] Furthermore, the elastic engaging piece of the upper member engages with the engaged portion, thereby mounting the upper member to the upper member assembly portion so that it can move up and down and tilt by a predetermined distance, and the locking frame of the intermediate valve body engages with the annular projection, thereby mounting the intermediate valve body to the intermediate valve body assembly portion so that it can tilt. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2019-74022 [Overview of the Initiative] [Problems that the invention aims to solve]

[0009] In the case of the fuel tank valve device described in Patent Document 1, the lower member has an engaged portion for engaging the upper member and an annular projection for engaging the intermediate valve body, which are provided in two stages in the axial direction on the upper member assembly portion and the intermediate valve body assembly portion of the lower member. Therefore, the lower member needs to have a predetermined length.

[0010] However, increasing the axial length of the lower member increases the axial length of the entire float valve, which presents the disadvantage of making it difficult to raise the fuel height when the opening is closed by the float valve, that is, the position where the fuel supplied to the fuel tank is full (the so-called lock point, SOH: Shut Off Height).

[0011] Therefore, an object of the present invention is to provide a fuel tank valve device that can shorten the axial length of the lower member, and consequently the axial length of the entire float valve, thereby raising the full tank limit position. [Means for solving the problem]

[0012] To achieve the above objective, the valve device for a fuel tank according to the present invention comprises a housing having a valve chamber communicating with a fuel tank at the bottom via a partition wall, a ventilation chamber communicating with a fuel vapor outlet at the top, and an opening in the partition wall connecting the valve chamber and the ventilation chamber; and a float valve housed in the valve chamber so as to be vertically movable and opening and closing the opening, wherein the float valve comprises a lower member forming a float body, an upper member assembled to the lower member above the lower member, and an intermediate valve body disposed between the lower member and the upper member, and the lower member has above it, The upper member and the intermediate valve body are assembled to an assembly portion, the outer circumference of the assembly portion is provided with a plurality of first protrusions that project radially outward and have a predetermined height in the axial direction, and a second protrusion is provided positioned between the plurality of first protrusions, the upper member has a first elastic engaging piece that engages with the first protrusions of the lower member, and the intermediate valve body has a second elastic engaging piece that engages with the second protrusions of the lower member, and the engagement surface of the second protrusion with respect to the second elastic engaging piece is located within the range of the axial height of the first protrusion. [Effects of the Invention]

[0013] According to the present invention, the intermediate valve body has a second elastic engaging piece that engages with the second projection of the lower member, and the engagement surface of the second projection with respect to the second elastic engaging piece is located within the axial height range of the first projection, so that the axial height of the engagement surface of the second projection with respect to the second elastic engaging piece and the engagement surface of the first projection with respect to the first elastic engaging piece can be brought closer together.

[0014] As a result, in a state where the upper member and the intermediate valve body are assembled to the lower member, the axial length of the float valve can be shortened. Therefore, compared with a float valve having a long axial length, the float valve can be raised to a higher position in the valve chamber, so that the full-tank regulation position can be raised.

Brief Description of the Drawings

[0015] [Figure 1] FIG. 8 is an exploded perspective view showing one embodiment of a fuel tank valve device according to the present invention. [Figure 2] FIG. 9 is an enlarged perspective view of a lower member constituting the valve device. [Figure 3] FIG. 10 shows an upper member constituting the valve device, where (a) is a perspective view thereof and (b) is a perspective view when viewed from a direction different from (a). [Figure 4] FIG. 11 is a perspective view of a state where the lower member and the intermediate valve body constituting the valve device are assembled. [Figure 5] FIG. 12 is a perspective view of a state where the lower member, the intermediate valve body, and the upper member constituting the valve device are assembled, with a part broken away. [Figure 6] FIG. 13 is a cross-sectional view of a float valve constituting the valve device. [Figure 7] FIG. 14 is a cross-sectional view of a state where the float valve in the valve device has descended and the opening is open. [Figure 8] FIG. 15 is a cross-sectional view of a state where the float valve in the valve device has risen and the opening is closed.

Mode for Carrying Out the Invention

[0016] (One Embodiment of a Fuel Tank Valve Device) Hereinafter, referring to FIGS. 1 to 8, one embodiment of a fuel tank valve device according to the present invention will be described.

[0017] In the following description, "fuel" means liquid fuel (including fuel droplets), and "fuel vapor" means evaporated fuel.

[0018] As shown in FIGS. 1 and 7, the fuel tank valve device 10 (hereinafter referred to as "valve device 10") in this embodiment has a housing 15 including a housing main body 20 having a substantially cylindrical shape with a partition wall 22 provided upward, an upper cover 30 mounted above the housing main body 20, and a lower cap 35 mounted below the housing main body 20.

[0019] Then, as shown in FIG. 7, by mounting the lower cap 35 below the housing main body 20, a valve chamber V communicating with a fuel tank (not shown) below the housing is formed via the partition wall 22, and by mounting the upper cover 30 above the housing main body 20, a ventilation chamber R communicating with a fuel vapor discharge port (not shown) above the housing is formed via the partition wall 22.

[0020] As shown in FIG. 1, the housing main body 20 has a substantially cylindrical shape with an open bottom, and has a main body peripheral wall 21 in which a ventilation groove 21a is formed at an intermediate portion in the axial direction. A plurality of locking claws 21b project from the outer peripheral lower edge portion of the main body peripheral wall 21. Further, a substantially annular flange portion 23 projects from above the main body peripheral wall 21, and a plurality of insertion holes 23a are formed in the flange portion 23. A plurality of locking claws 21c project at a position on the outer periphery of the main body peripheral wall 21 near the flange portion 23 and aligned with the insertion holes 23a.

[0021] Also, a ring mounting groove 24 is formed on the inner periphery of the flange portion 23, and the disk-shaped partition wall 22 is disposed inside the ring mounting groove 24. A circular opening 25 is formed at the center of the partition wall 22. Further, a substantially cross-shaped rib 25b is formed inside the opening 25. The rib 25b prevents the seal flange 83 (see FIGS. 6 to 8) from protruding from the inner peripheral edge on the front side of the opening 25.

[0022] Furthermore, as shown in Figures 7 and 8, a valve seat 25a, which is roughly circular in shape, is provided protruding from the rear (lower) edge of the opening 25. In addition, multiple thin, plate-like guide ribs 27 are formed on the inner circumference of the main body peripheral wall 21, from a point midway in its height direction to the partition wall 22.

[0023] On the other hand, the upper cover 30 has a roughly hat-like shape with its top closed, and a connecting pipe 32 extends outward from a predetermined location on the peripheral wall 31 of the cover. The connecting pipe 32 is connected to a tube that is connected to a canister (not shown) located outside the fuel tank.

[0024] The connecting pipe 32 extends from a fuel vapor outlet (not shown) provided in the cover peripheral wall 31. A frame-shaped locking piece 33 extends from below the cover peripheral wall 31, and each locking piece 33 has an engagement hole 34. The upper cover 30 is attached to the top of the housing body 20 by inserting the locking piece 33 into the corresponding insertion hole 23a of the housing body 20 and engaging the engagement hole 34 of the locking piece 33 with the corresponding locking claw 21c.

[0025] Then, as shown in Figure 7, the seal ring 17 fitted in the ring mounting groove 24 seals the gap between the inner circumference of the lower edge of the cover peripheral wall 31 of the upper cover 30 and the outer peripheral surface of the partition wall 22 of the housing body 20.

[0026] Furthermore, as shown in Figure 1, the lower cap 35 has a bottomed cap shape, having a substantially circular plate-shaped bottom wall 36 and a cap peripheral wall 37 that extends in a circle from the outer edge of the bottom wall 36. Multiple locking holes 37a are formed in the cap peripheral wall 37, and the locking claws 21b of the housing body 20 engage with these locking holes 37a, thereby attaching the lower cap 35 to the bottom of the housing body 20.

[0027] Furthermore, the bottom wall 36 has multiple passages 36a that connect the inside of the fuel tank to the valve chamber V. In addition, a spring support portion 39, which is roughly cross-shaped, is provided protruding from the center of the bottom wall 36 to support one end of the spring 38.

[0028] Furthermore, within the valve chamber V, a float valve 19 is positioned to be vertically movable between it and the lower cap 35 via a spring 38, opening and closing the opening 25 of the housing 15.

[0029] The float valve 19 in this embodiment mainly consists of a lower member 40 which forms a float body that generates buoyancy when immersed in fuel, an upper member 60 which is assembled above the lower member 40 so as to be able to move up and down by a predetermined distance relative to the lower member 40 and to be able to tilt, a sealing member 80 which is attached to the upper member 60, and an intermediate valve body 50 which is arranged between the lower member 40 and the upper member 60.

[0030] As shown in Figures 1 and 2, the lower member 40 has a lower body 41 which is cylindrical in shape with a predetermined diameter, and an assembly portion 43 which protrudes from the upper center of the lower body 41 and has a smaller diameter than the outer diameter of the lower body 41.

[0031] As shown in Figure 2, the assembly section 43 has a cylindrical assembly perimeter wall 44. Referring to Figures 2 and 6, this assembly perimeter wall 44 has a base portion 44a erected with a predetermined diameter, a shelf-like surface 44b that is flat and located at the end of the base portion 44a in the direction of erection, and a tip portion 44c that is erected from the shelf-like surface 44b and has a smaller diameter than the base portion 44a. That is, the base portion 44a is located below the assembly perimeter wall 44, and the tip portion 44c is located above it. In addition, a ceiling surface 44d is located at the end of the tip portion 44c in the direction of erection.

[0032] Furthermore, from the outer circumference of the tip portion 44c of the assembly peripheral wall 44, multiple first projections 45 are provided at equal intervals in the circumferential direction and facing radially outward, so as to protrude beyond the outer circumference of the base portion 44a (in this embodiment, there are four first projections 45, forming a roughly cross shape when viewed from the axial direction).

[0033] Each first projection 45 is provided at a predetermined height in the axial direction (it can also be said that it has a predetermined height in the axial direction), and its upper end in the axial direction (upper end at the tip in the protruding direction) has a tapered portion 45a that gradually increases in protrusion amount toward the lower member.

[0034] Furthermore, a first engagement surface 45b is formed on the lower side of the first projection 45, oriented perpendicular to the axis of the lower member 40. The first elastic engagement piece 70 of the upper member 60 can engage with this first engagement surface 45b of the first projection 45 (see Figure 5), and the upper member 60 is attached to the assembly portion 43.

[0035] The number of first projections 45 is not particularly limited, and the shape of the first projections 45 is also acceptable as long as they can engage with the first elastic engaging piece 70 provided on the upper member 60 as shown in Figure 3, etc.

[0036] Furthermore, a second projection 47 is provided on the upper outer circumference of the tip portion 44c of the assembly peripheral wall 44, between the first projections 45, 45, extending in a substantially arc shape along the circumferential direction of the tip portion 44c and projecting radially outward. This second projection 47 has a smaller diameter than the outer diameter of the base portion 44a.

[0037] Furthermore, a tapered surface is formed at the upper end of the second projection 47, and a second engagement surface 47a is formed on the lower side of the second projection 47, oriented perpendicular to the axis of the lower member 40. This second engagement surface 47a constitutes the "engagement surface of the second projection with respect to the second elastic engagement piece" in the present invention.

[0038] Then, as shown in Figure 6, the claw portion 51a of the intermediate valve body 50 engages with the second engagement surface 47a of the second projection 47, and the intermediate valve body 50 is mounted on the assembly portion 43.

[0039] Furthermore, the first projection 45 and the second projection 47 are arranged alternately along the circumferential direction of the assembly circumferential wall 44 when viewed from the axial direction of the float valve 19, and the second engagement surface 47a of the second projection 47 is positioned above the engagement surface 45b of the first projection 45.

[0040] Incidentally, a recess 46 is formed between the circumferentially adjacent first protrusions 45, 45 and the second protrusion 47 located between them, recessed to a predetermined depth in the circumferential direction (see Figure 2). It can also be said that the second protrusion 47 is formed above it via the recess 46. Furthermore, the second protrusion 47 connects multiple circumferentially adjacent first protrusions 45 of the assembly circumferential wall 44.

[0041] The shape of the second projection 47 is only required to be able to engage with the second elastic engaging piece 51 provided on the intermediate valve body 50 as shown in Figures 5 and 6.

[0042] Furthermore, as shown in Figures 2 and 6, a support projection 48 is provided protruding from the radial center of the ceiling surface 44d of the assembly portion 43, which pivotably supports the intermediate valve body 50.

[0043] As shown in Figure 6, the second engagement surface 47a of the second projection 47, which is the engagement surface with respect to the second elastic engagement piece 51, is located within the range of the axial height W1 of the first projection 45. Furthermore, in this embodiment, the second engagement surface 47a is located within the range of the axial height W2 of the tapered portion 45a formed on the first projection 45. Note that the axial height W1 of the first projection 45 and the axial height W2 of the tapered portion 45a refer to the length of the float valve 19 in the axial direction (direction along the axis).

[0044] Furthermore, as shown in Figure 2, the upper surface of the first projection 45 and the upper surface of the second projection 47 are located on the same plane.

[0045] Furthermore, as shown in Figures 4 and 6, a ventilation hole 49 is formed in the upper part of the lower body 41, penetrating axially through the lower body 41 and connecting the inside and outside of the lower body 41. The presence of this ventilation hole 49 allows air inside the lower body 41 to escape to the outside when the liquid level in the fuel tank reaches the lower end of the lower body 41, preventing excessive buoyancy from being generated in the lower body 41 and, consequently, the float valve 19. Multiple ventilation holes 49 may be formed.

[0046] Furthermore, as shown in Figure 4, a groove 49a is formed radially outward from a location above the lower body 41 that is radially opposite to the assembly portion 43. Through this groove 49a, a communication hole 49b is formed at the boundary between the assembly portion 43 and the upper surface of the lower body 41, penetrating the lower body 41 laterally and connecting the inside and outside of the lower body 41. This communication hole 49b allows internal air to be discharged from the lower body 41, thereby adjusting the buoyancy of the lower body 41.

[0047] Next, the intermediate valve body 50 will be described.

[0048] As shown in Figures 1, 4, 5, and 6, the intermediate valve body 50 of this embodiment has a roughly hat-like shape, with its upper end closed and a plurality of frame-shaped second elastic engagement pieces 51 provided around its outer circumference. Each second elastic engagement piece 51 has a claw portion 51a (see Figure 6) protruding from the inner side of its lower end, which engages with the second projection 47 of the lower member 40.

[0049] Each second elastic engaging piece 51 fits between circumferentially adjacent first projections 45, 45 provided on the mounting portion 43 of the lower body 41 (see Figure 4) and is also capable of engaging with the second projection 47 (see Figure 6).

[0050] Furthermore, as shown in Figure 6, a tapered surface 51b is formed on the inner side of the lower end of the claw portion 51a. This tapered surface 51b comes into contact with the tapered surface of the second projection 47 when the intermediate valve body 50 is pushed in and the second elastic engaging piece 51 is bent during assembly of the intermediate valve body 50 to the assembly portion 43, thereby facilitating the bending of the second elastic engaging piece 51.

[0051] Furthermore, a circumferential wall 53 is provided between a plurality of circumferentially adjacent second elastic engaging pieces 51, and a notch 55 is formed in this circumferential wall 53 that has a roughly arched shape (gate-shaped) with openings at the axial lower end and both radial sides. In addition, when the intermediate valve body 50 is attached to the assembly portion 43, the first projection 45 of the lower member 40 is inserted through the notch 55 and protrudes radially outward.

[0052] The notch 55 only needs to have an open lower end in the axial direction and a shape that allows the first projection to protrude radially outward. For example, it may be not only an arch shape as shown in Figure 4, but also rectangular or square frame-shaped. Furthermore, the minimum inner diameter of the multiple second elastic engaging pieces 51 is sized to match the outer diameter of the second projection 47 of the lower member 40.

[0053] Then, when attaching the intermediate valve body 50 to the assembly portion 43 of the lower member 40, the intermediate valve body 50 is pushed into the assembly portion 43 with each notch 55 aligned with the corresponding first projection 45.

[0054] Then, as shown in Figures 4 and 5, the first projection 45 fits into the notch 55 of the peripheral wall 53, forming a push guide (the notch 55 slides and guides the first projection 45), and the second elastic engaging piece 51 fits between the first projections 45, 45 of the lower body 41, and the claw portion 51a is pressed against the second projection 47 via the tapered surface 51b, causing each second elastic engaging piece 51 to bend and deform outward.

[0055] Subsequently, the claw portion 51a overcomes the second engagement surface 47a of the second projection 47, and each second elastic engagement piece 51 elastically returns to its original position, causing the claw portion 51a to engage with the second engagement surface 47a of the second projection 47, and the closed upper center of the intermediate valve body 50 is supported by the support projection 48, so that the intermediate valve body 50 is tiltably mounted on the lower member 40. In the state in which the intermediate valve body 50 is mounted on the assembly portion 43, the first projection 45 of the lower member 40 protrudes radially outward through the notch 55.

[0056] As shown in Figure 6, the intermediate valve body 50 normally abuts against the lower end of the shaft portion 81 of the sealing member 80, which will be described later, thereby closing the orifice hole 81b.

[0057] Next, the upper member 60 will be described.

[0058] As shown in Figures 3, 5, and 6, the upper member 60 of this embodiment has a ceiling portion 61 that moves toward and away from the valve seat 25a of the opening 25 provided in the partition wall 22, a substantially cylindrical outer wall 63 extending from the back surface (bottom surface) of the outer peripheral edge of the ceiling portion 61, and a frame-shaped first elastic engaging piece 70 that is on the back surface of the ceiling portion 61 and extends downward from the inside of the outer wall 63.

[0059] As shown in Figure 3(a), the ceiling portion 61 is roughly disc-shaped, with a slightly raised portion 65 formed in its radial center, and a circular support hole 67 formed inside this raised portion 65.

[0060] As shown in Figure 6, the shaft portion 81 of the sealing member 80 is inserted into the support hole 67. The sealing member 80 consists of a shaft portion 81 with a projection 81a on the outer circumference of its tip (lower end) and a sealing flange 83 that spreads out in an annular shape from the periphery of the base end (upper end) of the shaft portion 81, and is integrally formed from an elastic material such as rubber or elastic elastomer. The shaft portion 81 is also axially penetrating on its inside, and a small-diameter orifice hole 81b is formed in the center of the lower end.

[0061] Then, the shaft portion 81 is inserted from the front side of the support hole 67, and the projection 81a is locked to the back side periphery of the support hole 67, thereby attaching the seal member 80 to the upper member 60 with the seal flange 83 positioned on the surface (upper) side of the ceiling portion 61.

[0062] As shown in Figure 7, the orifice hole 81b connecting the upper and lower parts of the upper member 60 is normally closed by the intermediate valve body 50. Then, as shown in Figure 8, when the float valve 19 rises and the seal flange 83 of the seal member 80 contacts the valve seat 25a, closing the opening 25, the fuel level drops down, first the lower member 40 and the intermediate valve body 50 descend, opening the orifice hole 81b.

[0063] When the orifice hole 81b is opened, the open ventilation chamber R and the valve chamber V are connected, the pressure in the valve chamber V decreases, and the weight of the lower member 40 acts on the upper member 60, causing the seal flange 83 to smoothly detach from the valve seat 25a, opening the opening 25, and the entire float valve 19 to descend and return to the state shown in Figure 7.

[0064] Furthermore, as shown in Figures 3 and 5, multiple through-holes 69 are provided in the ceiling portion 61 at positions aligned with the first elastic engaging piece 70, and the inner surface of these through-holes 69 and the inner surface of the engaging hole 71 provided in the first elastic engaging piece 70 (see Figure 5) are formed to be continuous. In other words, the engaging hole 71 is formed via the through-holes 69.

[0065] The holes 69 may be, for example, round holes, square holes, or elongated holes extending along the circumferential direction of the ceiling, and their shape is not particularly limited, nor is their number particularly limited.

[0066] On the other hand, as shown in Figures 3 and 5, the outer wall 63 is substantially cylindrical in shape, extending downward for a predetermined length from the outer peripheral edge on the back side of the substantially disc-shaped ceiling portion 61. This outer wall 63 is positioned close to a plurality of guide ribs 27 (see Figures 7 and 8) provided on the inner circumference of the main body peripheral wall 21, and serves as a lifting guide for the upper member 60 when the float valve 19 is raised or lowered.

[0067] However, the outer wall is not limited to the cylindrical shape described above. For example, multiple columnar pieces may be extended downward from the back surface of the ceiling portion 61, and these may also serve as the outer wall, as long as they have guiding properties relative to the inner circumferential wall of the housing.

[0068] Furthermore, the first elastic engaging piece 70, which is on the back surface of the ceiling portion 61 and extends from the inside of the outer wall 63, extends from a position on the back surface of the ceiling portion 61 that is aligned with the hole 69. As shown in Figures 3(b) and 5, this first elastic engaging piece 70 extends from both side edges of the back surface of the hole 69, straddling the hole 69, and an elongated engaging hole 71 is provided inside it, extending for a predetermined length so as to be continuous with the hole 69.

[0069] Therefore, the first elastic engaging piece 70 has a roughly U-shaped frame. As shown in Figure 3(b), multiple adjacent first elastic engaging pieces 70 are connected by connecting walls 73 to ensure strength.

[0070] Furthermore, each first elastic engaging piece 70 extends beyond the leading edge in the extending direction of the outer wall 63. As shown in Figure 5, the minimum inner diameter of the multiple first elastic engaging pieces 70 is sized to match the outer diameter of the assembly peripheral wall 44 of the assembly portion 43 of the lower member 40.

[0071] Then, the first projection 45, which protrudes radially outward through the notch 55, fits inside the engagement hole 71 (see Figure 6), and the upper member 60 is assembled to the lower member 40 so that it can move up and down by a predetermined distance and can also tilt.

[0072] As shown in Figures 3(b) and 5, an R-shaped surface 75 with a predetermined curvature is formed on the inner surface of the leading end of each first elastic engaging piece 70 in the extending direction. This R-shaped surface 75 facilitates contact with the tapered portion 45a of the first projection 45 when the upper member 60 is pushed in and the first elastic engaging piece 70 is bent during assembly of the upper member 60 to the assembly portion 43, thereby facilitating the bending of the first elastic engaging piece 70.

[0073] Furthermore, chamfered portions 77, cut at a predetermined angle, are formed on both sides of the extending tip of each first elastic engaging piece 70. These chamfered portions 77 facilitate tilting when the upper member 60 tilts relative to the lower member 40.

[0074] (modified version) The shape, structure, layout, etc., of the housing, housing body, lower cap, upper cover, lower cap, lower member, intermediate valve body, upper member, sealing member, etc., that constitute the present invention are not limited to the above-described embodiments.

[0075] Furthermore, although the housing 15 in the above embodiment is composed of a housing body 20, an upper cover 30, and a lower cap 35, the housing only needs to have a structure that has at least a partition wall.

[0076] Furthermore, although the main body periphery wall 21 of the housing body 20 and the cover periphery wall 31 of the upper cover 30 in this embodiment are substantially cylindrical, they may also be elliptical or rectangular in shape.

[0077] Furthermore, in this embodiment, one float valve 19 is housed in one valve chamber V formed within the housing 15. However, for example, multiple float valves may be housed in one valve chamber (including valves that function as fuel cut-off valves, pressure regulating valves, etc., in addition to the full tank regulation valve), or multiple valve chambers may be defined within the housing, with a float valve housed in each valve chamber.

[0078] (Effects and Benefits) Next, the effects and advantages of the valve device 10 according to the present invention, which has the above configuration, will be explained.

[0079] Figure 7 shows a state where there is little fuel in the fuel tank (not shown), no buoyancy from the fuel acts on the float valve 19, and the opening 25 of the partition wall 22 is open.

[0080] From this state, when fuel is supplied to the fuel tank and the float valve 19 is immersed in the fuel, the float valve 19 rises due to the buoyancy of the float valve 19 itself and the biasing force of the spring 38, and as shown in Figure 8, the seal flange 83 of the seal member 80 attached to the upper member 60 comes into contact with the valve seat 25a of the opening 25, thereby closing the opening 25.

[0081] As a result, the air in the fuel tank loses its escape route, the pressure inside the fuel tank rises, and fuel rises through the fuel supply pipe. The fuel detection sensor in the fuel gun then detects the fuel level, stopping the refueling process and resulting in what is known as a full-tank restriction.

[0082] In this case, the buoyancy of the float valve 19 is mainly obtained by the lower member 40 being submerged below the fuel level. Therefore, the axial length of the lower member 40, and consequently the overall height of the float valve 19, affects the fuel level when the sealing member 80 reaches the valve seat 25a of the opening 25.

[0083] In other words, if the axial length of the lower member 40 is long, the overall height of the float valve 19 increases, so the timing at which the sealing member 80 of the float valve 19 contacts the valve seat 25a of the opening 25 and closes the opening 25 becomes earlier, and the liquid level that restricts the amount of fuel supplied to the fuel tank, i.e., the full tank restriction position, becomes lower, so the amount of fuel supplied to the fuel tank is reduced by that amount.

[0084] On the other hand, shortening the axial length of the lower member 40 delays the timing at which the sealing member 80 of the float valve 19 contacts the valve seat 25a of the opening 25 and closes the opening 25, causing the full tank restriction position to rise and increasing the amount of fuel supplied to the fuel tank by that amount.

[0085] Furthermore, in this valve device 10, the height of the lower member 40 can be reduced, which in turn reduces the overall height of the float valve 19 and allows the full tank restriction position to be raised.

[0086] In other words, in this valve device 10, at the assembly portion 43 of the lower member 40, the engagement surface (second engagement surface 47a) of the second projection 47 that engages with the intermediate valve body 50 is located within the axial height range of the first projection 45 that engages with the upper member 60, and the second elastic engagement piece 51 of the intermediate valve body 50 fits between the first projections 45 and engages with the second projection 47 (see Figures 2 and 6), while the first elastic engagement piece 70 of the upper member 60 engages with the first projection 45 that extends from between the second elastic engagement pieces 51 of the intermediate valve body 50 (see Figure 5).

[0087] Therefore, when the float valve 19 is assembled by attaching the intermediate valve body 50 and the upper member 60 to the lower member 40, the axial height of the engagement surface of the second projection 47 with respect to the second elastic engagement piece 51 (second engagement surface 47a), which is the engagement surface between the lower member 40 and the intermediate valve body 50, and the engagement surface of the first projection 45 with respect to the first elastic engagement piece 70 (first engagement surface 45b), which is the engagement surface between the lower member 40 and the upper member 60, can be brought closer together.

[0088] Therefore, compared to the structure described in Patent Document 1 above, in which the engaging portion for locking the upper member and the annular projection for locking the intermediate valve body are arranged in two stages, the axial length of the lower member and the axial length (total height) of the entire float valve assembled to the lower member with the intermediate valve body and upper member attached can be shortened.

[0089] As a result, the height of the lower member 40 can be reduced, thus reducing the overall height of the float valve 19. This allows the full tank restriction position to be raised, increasing the amount of fuel supplied to the fuel tank. Furthermore, because the full tank restriction position can be raised, the full tank detection liquid level of the fuel tank can be set higher up on the tank, making it easier to apply to thin tanks and improving tank layout flexibility.

[0090] In this embodiment, the valve device 10 functions as a so-called full-tank regulating valve, which closes the opening 25 to prevent further over-fueling when the liquid level in the fuel tank reaches a set full-tank level, as described above. However, it may also function as a so-called fuel spill prevention valve, which closes the opening 25 to prevent fuel from leaking out when the liquid level in the fuel tank rises abnormally due to fuel oscillation or the like.

[0091] For example, if a vehicle turns a curve, travels on uneven roads or slopes, or overturns or flips over due to an accident, causing the fuel in the fuel tank to oscillate and the fuel level to rise, the float valve 19 rises due to the biasing force of the spring 38 and the buoyancy of the float valve 19 itself. The seal flange 83 of the seal member 80 then contacts the rear peripheral edge of the opening 25, closing the opening 25. This prevents fuel from flowing into the ventilation chamber R through the opening 25, thus preventing fuel leakage to the outside of the fuel tank.

[0092] Furthermore, in this embodiment, a tapered portion 45a is formed at the upper axial end of the first projection 45, and the engagement surface (second engagement surface 47a) of the second projection 47 with respect to the second elastic engagement piece 51 is located within the range of the axial height W1 of the tapered portion 45a (see Figure 6).

[0093] According to the above embodiment, since a tapered portion 45a is formed at the upper end of the first projection 45 in the axial direction, when assembling the upper member 60 to the lower member 40, the first elastic engaging piece 70 is pressed against the tapered portion 45a of the first projection 45 and bends in the outer diameter direction of the upper member 60, making it easier to overcome the first projection 45. This improves the ease of assembling the upper member 60 to the assembly portion 43 of the lower member 40.

[0094] Furthermore, since the second engagement surface 47a is located within the axial height range of the tapered portion 45a, the axial heights of the engagement surface of the second projection 47 with respect to the second elastic engagement piece 51 (second engagement surface 47a) and the engagement surface of the first projection 45 with respect to the first elastic engagement piece 70 (first engagement surface 45b) can be brought closer together, thereby shortening the axial length of the float valve 19.

[0095] Therefore, the full tank limit position can be raised while improving the ease of assembly of the upper member 60 to the lower member 40.

[0096] Furthermore, in this embodiment, the intermediate valve body 50 has a plurality of second elastic engaging pieces 51, and a peripheral wall 53 is provided between the plurality of second elastic engaging pieces 51. The peripheral wall 53 has a notch 55 that is open at its axial lower end, and the first projection 45 protrudes radially outward through the notch 55 (see Figure 4).

[0097] According to the above embodiment, the intermediate valve body 50 has a plurality of second elastic engaging pieces 51, and a peripheral wall 53 is provided between the plurality of second elastic engaging pieces 51. The peripheral wall 53 has a notch 55 that is open at its axial lower end. Therefore, when assembling the intermediate valve body 50 to the lower member 40, the notch 55 provided in the peripheral wall 53 acts as a guide, further improving the ease of assembling the upper member 60 to the lower member 40.

[0098] Furthermore, in this embodiment, the upper surface of the first projection 45 and the upper surface of the second projection 47 are arranged on the same plane (see Figure 2).

[0099] According to the above embodiment, since the upper surface of the first projection 45 and the upper surface of the second projection 47 are located on the same plane, the shape of the assembly portion 43 of the lower member 40 can be simplified, and the moldability of the lower member 40 can be improved.

[0100] Furthermore, since the upper surface of the first projection 45 and the upper surface of the second projection 47 are on the same plane, the axial height of the lower member can be reduced, and the full tank restriction position can be raised further.

[0101] It should be noted that the present invention is not limited to the embodiments described above, and various modified embodiments are possible within the scope of the gist of the present invention, and such embodiments are also included in the scope of the present invention. [Explanation of Symbols]

[0102] 10. Valve device for fuel tank (valve device) 15 Housing 19. Float valve 20 Housing body 40 Lower Member 43 Assembly section 45 1st protrusion 45a Tapered section 47 Second protrusion 50 Intermediate valve body 51 Second elastic engaging piece 53 Peripheral wall 55 Notches 60 Upper component 61 Ceiling 70 First elastic engaging piece

Claims

1. A housing is provided with a valve chamber communicating with a fuel tank at the bottom via a partition wall, and a ventilation chamber communicating with a fuel vapor outlet at the top, and an opening is provided in the partition wall connecting the valve chamber and the ventilation chamber. The valve chamber is housed in a vertically movable manner and comprises a float valve that opens and closes the opening, The float valve comprises a lower member forming the float body, an upper member mounted to the lower member above the lower member, and an intermediate valve body positioned between the lower member and the upper member. The lower member has an assembly portion above it to which the upper member and the intermediate valve body are assembled. The outer circumference of the assembly portion is provided with a plurality of first protrusions that project radially outward and have a predetermined height in the axial direction, and a second protrusion is provided positioned between the plurality of first protrusions. The upper member has a first elastic engaging piece that engages with the first projection of the lower member, The intermediate valve body has a second elastic engaging piece that engages with the second projection of the lower member, A valve device for a fuel tank, characterized in that the engagement surface of the second projection with respect to the second elastic engagement piece is located within the axial height range of the first projection.

2. A tapered portion is formed at the upper end of the first projection in the axial direction. The valve device for a fuel tank according to claim 1, wherein the engagement surface of the second projection with respect to the second elastic engagement piece is located within the axial height range of the tapered portion.

3. The intermediate valve body has a plurality of second elastic engaging pieces, and a peripheral wall is provided between the plurality of second elastic engaging pieces. The valve device for a fuel tank according to claim 1 or 2, wherein the peripheral wall has a notch with an axial lower end that is open, and the first projection protrudes radially outward through the notch.

4. The valve device for a fuel tank according to claim 1 or 2, wherein the upper surface of the first projection and the upper surface of the second projection are located on the same plane.

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