JP2010006291A - Fuel shutoff valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the installability of a two-part float of a fuel shutoff valve. <P>SOLUTION: This fuel shutoff valve 10 has a casing 20 and a float 50. The casing 20 includes a casing body 30 having a cylindrical sidewall part 32 and a lid body 40 arranged in an upper part of the sidewall part 32. The lid body 40 includes a lid body 41 covering a part of an opening in the upper part of the sidewall part 32 and having a connection passage 44a, a welding part 42a formed in an outer peripheral part of the lid body 41 to be thermally weldable on an upper part of a fuel tank FT, and a seal part 44b arranged to face to the connection passage 44a and seated with an upper part of the float 50. The two-part float has an engaging claw and an annular engaging projection 56 in a first float on an outer peripheral side and in a second float on an inner peripheral side, respectively. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

  Conventionally, as the fuel cutoff valve of this type, the technique shown in FIG. 3 described in Patent Document 1 is known. A conventional fuel cutoff valve is mounted on the tank upper wall of the fuel tank FT, and includes a casing that forms a valve chamber and a connection passage that connects the valve chamber and the outside, a float that is housed in the valve chamber, A spring that biases the float upward, and the float moves up and down according to the fuel level in the valve chamber to open and close the connection passage, thereby ensuring ventilation between the inside and outside of the fuel tank and the outside of the fuel To prevent spillage.

  In the conventional float, in order to increase the volume of the float and prevent deformation due to sink marks at the time of injection molding, the float is separately molded in the first float and the second float and assembled. However, in order to engage the plurality of engagement holes formed at predetermined positions of the first float and the plurality of engagement claws of the second float corresponding to the engagement holes, the first float and the second float are surrounded. It was necessary to position and assemble in the direction.

JP 2007-30806 A

  An object of the present invention is to provide a fuel cutoff valve that can be assembled without positioning the first float and the second float in view of solving the above-described problems of the prior art.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

[Application Example 1]
A casing that is attached to the upper part of the fuel tank and has a valve chamber connected to the fuel tank and a connection passage that connects the valve chamber and the outside, and is moved up and down by the fuel level stored in the valve chamber. In the fuel cutoff valve having a float that opens and closes the connection passage and a spring that biases the float in the valve closing direction,
The casing includes a casing body having a cylindrical side wall portion, and a lid disposed on an upper portion of the side wall portion, and the lid body covers a part of the upper opening of the side wall portion and the connection passage. A lid body having a seal portion on which the upper part of the float is seated and arranged facing the connection passage,
The float is
A valve portion for opening and closing the connection passage, a float chamber opened downward, and a cup-shaped first float having an engagement portion;
A second float that is integrated with the first float by being housed in the float chamber and has an annular engagement protrusion;
The engagement portion and the annular engagement protrusion are integrated by engagement means.

  In the float described in Application Example 1, the first float and the second float are integrally formed, and the annular engagement protrusion of the second float is formed with an engagement protrusion on the entire circumference of the second float. Therefore, if the engaging portion of the first float is in a position facing the annular engaging protrusion, the second float is coaxially stored in the storage chamber of the first float and can be assembled in any circumferential direction. No circumferential positioning is required.

[Application Example 2]
In Application Example 2, the engagement portion may be configured with engagement claws formed along the lower sidewalls of the plurality of through holes that penetrate the sidewall of the first float. By using a through-hole, a slide core can be inserted from the outer periphery of the first float and injection molding can be performed. Therefore, there is no need to forcibly remove the float core in a small space and to configure the slide core in the core mold. Can be injection molded by configuration. Further, the shape of the engagement hole and the engagement claw may be any shape that engages with the annular engagement protrusion.

  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 Shutoff Valve 10 FIG. 1 is a side view showing the fuel cutoff valve 10, and FIG. 2 is a cross-sectional view showing the fuel cutoff valve 10. The surface of the fuel tank FT is made of a composite resin material containing high-density 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 includes a casing 20, a float 50, and a spring 70 as main components. When the fuel in the fuel tank FT rises to a predetermined liquid level, the fuel cutoff valve 10 flows out to the outside (canister). Is to regulate. Hereinafter, the configuration and operation of each part of the fuel cutoff valve 10 will be described.

(2) Configuration of each part of fuel cutoff valve 10 (2) -1 casing 20
FIG. 3 is an exploded cross-sectional view of the fuel cutoff valve 10. The casing 20 includes a casing body 30 and a lid body 40. A space surrounded by the casing body 30 and the lid body 40 is a valve chamber 20S, and a float supported by a spring 70 in the valve chamber 20S. 50 is stored.

  The casing body 30 is made of polyacetal and includes a cylindrical side wall portion 32 and a bottom wall portion 34 formed integrally with a lower portion of the side wall portion 32, and is surrounded by the side wall portion 32 and the bottom wall portion 34. A cup-shaped valve chamber 20S is formed. A communication hole 32a is formed in the side wall portion 32, and a communication hole 34a is formed in the bottom wall portion 34 to communicate the fuel tank FT and the valve chamber 20S. A spring receiving portion 34 b that supports the lower end of the spring 70 is formed at the center upper portion of the bottom wall portion 34.

The lid 40 is made of high-density polyethylene having a larger fuel swelling amount than polyacetal, and covers a lid body 41 that covers the upper opening of the side wall portion 32, and a weld portion that is formed on the outer periphery of the lid body 41 and is welded to the fuel tank FT. A flange 42 having 42a, a tube part 43 having a tube passage 43a projecting in the horizontal direction from the upper part of the lid body 41, and a passage forming part 44 are provided. The lid body 41 includes a flat plate portion 41a that covers the outer peripheral portion of the upper opening of the side wall portion 32, and a raised portion 41b that protrudes upward from the flat plate portion 41a. The raised portion 41 b includes a cylindrical standing wall portion 41 c and a top plate portion 41 d formed on the upper portion of the standing wall portion 41 c and parallel to the lid body 41.
A cylindrical passage forming portion 44 is formed at the center of the top plate portion 41d of the lid body 41 so as to face downward. A connecting passage 44a passes through the passage forming portion 44, and an annular seal portion 44b is formed on the valve chamber 20S side of the connecting passage 44a.

(2) -2 Mounting means A mounting means is provided as a configuration for mounting the casing body 30 to the lid body 40. The mounting means includes a holding portion 36 provided in the casing body 30, a cylindrical insertion portion 45 provided in the lid body 40, and a coupling means for mechanically coupling the casing body 30 and the lid body 40 with claws. It has.
FIG. 4 is an exploded side view of the fuel cutoff valve. The holding portion 36 includes a plurality of (four in the embodiment) support leg portions 36a and an annular connection portion 36b that connects the upper portions of the support leg portions 36a. The support leg 36 a is projected from the outer wall of the side wall 32 in an L-shaped cross section. FIG. 5 is a cross-sectional view taken along line 5-5 of FIG. The annular coupling part 36 b forms a holding gap 38 </ b> S in which the insertion part 45 can be inserted between the annular part 36 b and the side wall part 32 by separating a predetermined gap from the outer peripheral wall of the side wall part 32 of the casing body 30.
In addition, a plurality of first ribs 38 are formed in the vertical direction on the inner peripheral portion of the annular coupling portion 36b. The first rib 38 is formed in the vertical direction so as to contact the insertion portion 45 across the holding gap 38S.

  3 and 4, the connecting means includes an engaging portion 36 c provided in the holding portion 36 and an engaging hole 45 a formed in the insertion portion 45. The engagement portion 36c is a cantilever member formed below the annular coupling portion 36b and having a slit 36e between the engagement leg 36a and the upper portion of the engagement portion 36c. An engaging claw 36d is formed at the tip of the engaging portion 36c. On the other hand, an engagement hole 45a is formed in the insertion portion 45, and the casing body 30 is supported by the lid body 40 when the engagement claw 36d engages with the engagement hole 45a. Further, the insertion portion 45 is formed with a notch 45b upward from the bottom. The notch 45b is disposed so as to coincide with the communication hole 32a, and communicates with the valve chamber 20S through the communication hole 32a.

(2) -3 Float 50
In FIG. 3, the float 50 includes a cup-shaped first float 51 and a cylindrical second float 54. FIG. 7 is a perspective view of the first float 51. The 1st float 51 has the engaging part comprised by two or more places in the 1st float lower part by the valve part 53 protrudingly provided by the upper part, and the through-hole 52a and the engaging claw 52b. The through hole 52a is formed through the side wall of the first float 51, and an engaging claw 52b is formed along the lower wall of the through hole 52a that does not protrude from the first float inner peripheral wall to the inner peripheral side. The 1st float 51 is constituted by the shape of a container which opened the lower part, and forms float room 50S.

  FIG. 8 is a perspective view of the second float 54. FIG. 9 is a bottom view of the second float 54. The second float 54 has a cylindrical shape, and has an annular engagement protrusion 55 at the lower part of the outer periphery and an annular protrusion 56 having a diameter slightly smaller than the annular engagement protrusion 55 at the upper part. And a second rib 57 that connects the annular protrusion 56 in the axial direction. The outer diameter of the annular engagement protrusion 55 is larger than the second rib because it requires an engagement allowance, and the annular engagement protrusion 55 corresponds to the space between the plurality of second ribs 57. A discharge hole 59 is provided. The second float 54 penetrates from the bottom surface to the top surface, and a housing portion 58 capable of housing the spring 70 is formed.

  The first float 51 and the second float 54 are inserted into the float chamber 50S from the upper part of the second float 54. When the annular engagement protrusion 55 passes over the engagement claw 52b and is positioned in the through hole 52a, the first float 51 and the second float The assembly of the float 54 is completed. The spring 70 is accommodated in the accommodating portion 58 and directly biases the first float 51.

(3) Installation Work to Fuel Tank FT Next, an operation for mounting the fuel cutoff valve 10 on the tank upper wall FTa of the fuel tank FT will be described. As shown in FIG. 2, the float 50 and the spring 70 are accommodated in the valve chamber 20 </ b> S of the casing body 30. Further, as shown in FIGS. 3 and 5, the insertion portion 45 of the lid body 40 is inserted into the holding gap 38 </ b> S of the holding portion 36 of the casing body 30. At this time, the engagement claw 36d is engaged with the engagement hole 45a of the insertion portion 45 of the lid 40. Thereby, the insertion part 45 is clamped by the holding part 36, and the engaging claw 36d is engaged with the engaging hole 45a, whereby the lid body 40 and the casing body 30 are integrated.

  Subsequently, as shown in FIG. 2, the lower end portion of the welded portion 42 a of the lid body 40 is melted by a hot plate (not shown), and the hot plate (not shown) is provided along the periphery of the mounting hole FTb of the fuel tank FT. To be a welded portion FTd. The casing body 30 is inserted into the mounting hole FTb from below, and the welded portion 42a is pressed against the welded portion FTd. Thereby, since the welding part 42a and the welding part FTd are formed with the same resin material, both will weld each other when it solidifies by cooling. As described above, when the lid 40 is welded to the tank upper wall FTa, the inside of the fuel tank FT is secured with high sealing performance against the outside.

(4) Operation of the fuel cutoff valve 10 Next, the operation of the fuel cutoff valve 10 will be described. In FIG. 2, when the fuel level in the fuel tank FT is below a predetermined level, the float 50 is in the lowered position, and the connection passage 44a is opened to ensure ventilation between the fuel tank FT and the outside. . When the fuel level in the vicinity of the fuel shut-off valve 10 rises due to the vehicle swinging or tilting, the fuel vapor accumulated in the upper part of the fuel tank FT passes through the communication hole 32a (FIG. 3) and the valve chamber 20S. , Escape to the canister side through the connection passage 44a and the tube passage 43a. When the fuel level in the fuel tank FT reaches a predetermined level, the fuel flows into the valve chamber 20S through the communication hole 34a of the bottom wall portion 34. As a result, buoyancy is generated in the float 50 and the valve 50 is seated on the seal portion 44b to close the connection passage 44a and prevent the fuel from flowing out to the canister side. Accordingly, it is possible to prevent the fuel vapor from escaping from the fuel tank FT and the fuel from flowing out of the fuel tank FT due to the rise of the fuel liquid level in the fuel tank FT.

(5) Operation and effect of embodiment The following operation and effect are achieved by the configuration of the above embodiment.
(5) -1 Since the lid 40 is formed of the same high-density polyethylene as the fuel tank FT, it does not require a fastening member or the like, and can be easily fixed to the upper portion of the fuel tank FT by heat welding.

(5) -2 The seal portion 44b is formed integrally with the raised portion 41b of the lid 40, and the connection passage 44a is closed by the valve portion 53 of the float 50 being seated, so that the inside of the fuel tank FT is external to the outside. And sealed. Therefore, the present embodiment does not require a sealing member and reduces the number of parts compared to the conventional technique in which a sealing portion is provided in the casing body and the casing body is assembled with a sealing member interposed in the casing body. Can do.

(5) -3 As shown in FIG. 6, since the seal portion 44 b is formed in the raised portion 41 b higher than the flat plate portion 41 a of the lid body 41, the sealing performance is not deteriorated due to fuel swelling. That is, fuel swelling occurs in the lid main body 41 due to the fuel vapor filled in the fuel tank FT. At this time, since the lid 40 is welded and restrained to the fuel tank FT, the flat plate portion 41a of the lid body 41 is curved so as to rise upward as indicated by a two-dot chain line, and is not circumferentially oriented. Uniform deformation may occur. The raised portion 41b is separated from the welded portion 42a constrained by the fuel tank FT, and is not easily affected by such uneven deformation of the flat plate portion 41a, and the fuel swells uniformly, so that the seal portion 44b has a large size. No change in shape. Therefore, the seal portion 44b is less affected by the shift of the central axis and the change of the shape due to the swelling of the fuel, and can maintain high sealing performance.

(5) -4 As shown in FIG. 3 and FIG. 4, the mounting means can easily assemble the casing body 30 and the lid body 40 and hold them firmly. That is, when the insertion portion 45 of the lid 40 is inserted into the holding gap 38S of the holding portion 36, the insertion portion 45 is held in the holding gap 38S, and the engaging claw 36d of the connecting means is engaged with the engaging hole 45a. In combination, the casing body 30 and the lid body 40 are easily connected. At this time, since the insertion portion 45 is abutted and supported by the first rib 38 projecting from the holding portion 36, the casing body 30 is mounted without being inclined with respect to the lid body 40, and the float 50 is displaced. Therefore, it is possible to perform a stable raising / lowering operation.

(5) -5 The mounting means holds firmly even if the lid 40 is larger than the casing body 30 and the fuel swells. That is, the lid 40 is made of high-density polyethylene and has a larger fuel swelling amount than the casing body 30 made of polyacetal. For this reason, even if the insertion part 45 formed in the lid body 40 expands due to fuel swelling from the holding part 36 of the casing body 30, the swollen part expands in the holding gap 38 </ b> S, and the casing body 30 tilts. Does not produce a strong force. Therefore, the casing body 30 is not rattled with respect to the lid body 40, and there is a problem associated with rattling, that is, the float 50 does not move up and down in a tilted state, and a stable opening / closing characteristic can be obtained. .

(5) -6 When the insertion portion 45 is inserted into the holding gap 38S, the first rib 38 is easily elastically deformed by being pushed by the insertion portion 45, so that the allowable range of the dimensional tolerance of the holding gap 38S can be set large. .

(5) -7 The annular connecting part 36b of the holding part 36 has a structure in which the upper part of the support leg part 36a is connected in an annular shape, and holds the base of the insertion part 45. Compared with the structure formed by dividing the insertion portion 45, it is possible to suppress the insertion portion 45 from expanding with fuel swelling with a large force.

(5) -8 Since the engaging portion 36c and the engaging hole 45a constituting the connecting means are formed integrally with the annular connecting portion 36b and the insertion portion 45, respectively, the configuration of the mold can be simplified.

(5) -9 Since the annular engagement protrusion 55 is formed on the entire circumference of the lower part of the second float 54, the circumferential direction of the second float 54 is inserted in the first float 51 in any circumferential direction. Positioning is not required and can be assembled easily.

(5) -10 The spring 70 is accommodated in the accommodating portion 58 of the second float 54. However, since the spring 70 directly urges the first float 51, it is the same as when the float 50 is composed of one component. In addition, the opening / closing accuracy of the float 50 to the seal portion 44b can be maintained.

(5) -11 By using the second rib 57 on the outer periphery of the second float 54, it is possible to easily adjust the outer diameter by simply cutting a portion corresponding to the second rib of the mold.

(5) -12 By providing the discharge hole 59 in the annular engagement protrusion 55, the fuel that has flowed into the first float 51 and the second float 54 can be discharged from the discharge hole 59.

(5) -13 By forming the through hole 52a in the side surface of the first float 51, the slide core can be inserted from the outer periphery of the first float 51 and can be injection-molded. There is no need to configure a slide core in the core mold. Since the core mold is small, if a plurality of slide cores are configured in the core mold, it is difficult to make a mold and the mold structure is complicated. However, in the case of a structure in which the slide core is inserted from the outer peripheral side of the first float 51, the slide core can be attached to a wide part of the mother die, so that the mold configuration can be simplified.

(6) Other Embodiments 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.
(6) -1 In the above embodiment, as shown in FIG. 5, the first rib 38 protrudes from the inner wall of the annular coupling portion 36b. Or a holding gap between the side wall portion of the casing body and the insertion portion, and may be provided on the inner wall of the insertion portion or the outer wall of the side wall portion. May be.
(6) -2 In the above embodiment, the casing main body constituting the casing is integrally formed with the side wall portion and the bottom wall portion. However, the present invention is not limited to this, and the same effects can be obtained even if formed separately. .

It is a side view which shows a fuel cutoff valve. It is sectional drawing which shows a fuel cutoff valve. It is sectional drawing which decomposed | disassembled the fuel cutoff valve. It is the side view which decomposed | disassembled the fuel cutoff valve. FIG. 5 is a cross-sectional view taken along line 5-5 of FIG. It is explanatory drawing explaining the effect | action of a fuel cutoff valve. It is a perspective view of a 1st float. It is a perspective view of a 2nd float. It is a bottom view of the 2nd float.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fuel cutoff valve 20 ... Casing 20S ... Valve chamber 30 ... Casing main body 32 ... Side wall part 32a ... Communication hole 34 ... Bottom wall part 34a ... Communication hole 34b ... Spring receiving part 36 ... Holding part 36a ... Support leg part 36b ... Ring shape Connecting portion 36c ... engaging portion 36d ... engaging claw 36e ... slit 38 ... first rib 38S ... holding gap 40 ... lid body 41 ... lid body 41a ... flat plate portion 41b ... raised portion 41c ... standing wall portion 41d ... top plate portion 42 ... Flange 42a ... Welding part 43 ... Tube part 43a ... Tube passage 44 ... Passage forming part 44a ... Connection passage 44b ... Seal part 45 ... Insertion part 45a ... Engagement hole 45b ... Notch 50 ... Float 50S ... Float chamber 51 ... first float 52 ... engaging portion 52a ... through hole 52b ... engaging claw 53 ... valve portion 54 ... second float 55 ... annular engagement projection 56 ... annular projection 57 ... second rib 58 ... accommodating part 59 ... discharge hole 70 ... spring FT ... fuel tank FTa ... tank upper wall FTb ... mounting hole FTd ... welded part

Claims (2)

A casing (20) having a valve chamber (20S) attached to an upper portion of the fuel tank (FT) and connected to the fuel tank (FT) and a connection passage (44a) connecting the valve chamber (20S) and the outside. And a float (50) which is housed in the valve chamber (20S) and moves up and down by the fuel level in the valve chamber (20S) to open and close the connection passage (44a), and the float (50) is closed. In a fuel shut-off valve having a spring (70) for biasing a directional force,
The casing (20) includes a casing body (30) having a cylindrical side wall (32), and a lid (40) disposed on the upper side of the side wall (32). The lid (40 ) Covers a part of the upper opening of the side wall portion (32) and has the connection passage (44a) and the cover body (41), and faces the connection passage (44a). A seal part (44b) on which the upper part is seated,
The float (50)
A valve portion (53) for opening and closing the connection passage (44a), a float chamber (50S) opened downward, and a cup-shaped first float (51) having an engagement portion (52),
A second float (54) integrated with the first float (51) by being accommodated in the float chamber (50S) and having an annular engagement protrusion (55);
A fuel cutoff valve integrated by an engagement means in the engagement portion (52) and the annular engagement protrusion (55). The fuel cutoff valve according to claim 1,
The engagement portion (52) is a fuel cutoff valve configured with engagement claws (52b) formed along lower walls of a plurality of through holes (52a) penetrating the side wall of the first float.

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