JP2008062878A - Fuel tank mounting part - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To maintain high sealability by an O-ring even if a cover is swelled, and prevent the deformation of the cover such as a change in inner diameter. <P>SOLUTION: An inner tube 12 of an easy-to-swell cover 1 is held between an inner peripheral tube 20a and an outer peripheral tube 20b of a hard-to-swell case 2. An O-ring 4 is interposed at the overlapped part thereof. Even if the inner tube 12 is swelled by fuel, the swelling is restrained by both the outer diameter side and the inner diameter side. Consequently, the deterioration of sealing performance caused by the O-ring can be surely prevented. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a tank mounting component attached to a resin fuel tank such as a backflow prevention valve.

  Various valve devices such as a backflow prevention valve and an evaporation circuit valve are attached to a fuel tank of an automobile. In recent years, the fuel tank has been made of resin, and these valve devices are generally joined to the resin fuel tank by welding.

  For example, a backflow prevention valve for preventing the fuel in the fuel tank from flowing back into the fuel supply pipe is interposed between the fuel tank and the fuel supply pipe. Japanese Patent Application Laid-Open No. 11-078549 describes a backflow prevention valve in which a guide protrusion that extends toward the upstream side is formed on a valve body. This type of backflow prevention valve includes a valve body, a case having a sealing surface that contacts and seals the valve body, and a movably storing valve body, and a cover that is coupled to the case and covers the opening of the fuel tank. It is configured.

  The cover is generally joined to the fuel tank by thermal welding. Therefore, it is necessary to form the cover from a resin that can be welded to the resin constituting the outer surface of the fuel tank, and is formed from high-density polyethylene or the like. On the other hand, the case and the cover are formed separately because of the necessity to house and assemble the valve body, and are integrated by mechanical means such as claw engagement. Therefore, the case has a wide variety of resin types, and is therefore formed of polyacetal, polyamide, or the like that does not easily swell with fuel. An O-ring is interposed between the case and the cover to seal fuel leakage.

  However, a cover made of high-density polyethylene or the like has a problem that hydrocarbons are easily permeable and easily swelled by fuel. In order to make it difficult for hydrocarbons to permeate, there is a method of forming a so-called gas barrier layer by coating a poorly fuel permeable resin such as ethylene vinyl alcohol copolymer (EVOH). However, the gas barrier layer made of these resins has a problem that the bonding strength by heat welding is low, and it is desirable not to form the gas barrier layer on the welding surface of the cover with the fuel tank.

Therefore, in Japanese Patent Application Laid-Open No. 2003-002074, a through hole is formed on the side surface of a cylindrical primary molded body made of high-density polyethylene, and a gas barrier layer is molded on the inner periphery of the primary molded body. A fuel tank accessory is described in which a gas barrier layer bulges from the outer periphery to the outer peripheral side, and a connecting portion with other parts is formed at that portion. According to this technique, it is possible to achieve both heat weldability and gas barrier properties.
JP 11-0778549 JP 2003-002074 A

  In the backflow prevention valve described in Patent Literature 1, an O-ring is interposed between the inner peripheral surface of the cylindrical portion that advances from the cover into the fuel tank and the outer peripheral surface of the case inserted into the cylindrical portion. . For this reason, when the cylindrical portion of the cover is swollen by the fuel, the cylindrical portion expands in the radial direction, and there is a problem that the sealing performance by O-ring is lowered. The backflow prevention valve needs to reliably prevent the fuel from flowing back to the fuel filler port, and a reduction in the sealing performance between the cover and the case should be avoided.

  In addition, gas barrier layers such as EVOH are difficult to permeate hydrocarbons, but have the problem of being easily swelled by fuel, like high-density polyethylene. Therefore, in the structure described in Patent Document 2, a cylindrical primary molded body formed of high-density polyethylene and having a gas barrier layer on the inner periphery has an inner peripheral side that is constrained by the connecting portion (19) on the outer peripheral side. Since it is not restrained, it is incapable of swelling. Therefore, the primary molded body and the gas barrier layer may locally swell and the inner diameter may be locally small (circle → elliptical). When the inner diameter changes in this manner, uniform sealing is not achieved, and the O-ring tightening margin cannot be secured at locations where the inner diameter is locally reduced, resulting in a decrease in sealing performance.

  The present invention has been made in view of such circumstances, and an object to be solved is to maintain high sealing performance by O-ring even when the cover swells and to prevent deformation such as a change in inner diameter.

A feature of the fuel tank mounting part of the present invention that solves the above-described problem is a fuel tank mounting part that is attached to a resin fuel tank, and is protruded from the surface of the flange part that is joined to the outer surface of the fuel tank. A cover having an inner cylinder portion that advances into the fuel tank;
A ring-shaped gripping part that is formed from a resin that is hardly swellable with respect to the fuel, has an inner peripheral cylindrical part and an outer peripheral cylindrical part, and surrounds the inner and outer circumferences of the inner cylindrical part all around, and the gripping part into the fuel tank A cylindrical case main body that advances, and a case that is held by the cover with the gripping part gripping the inner cylindrical part,
And an o-ring interposed between the cover and the case at the overlapping position of the grip portion and the inner cylinder portion.

  When the cover has an outer cylinder part that protrudes from one surface of the flange part and extends to the outside of the fuel tank and is coupled to other parts, the inner peripheral cylinder part of the case extends to the inner periphery of the outer cylinder part of the cover. It is desirable that

  The O-ring is preferably interposed between the outer peripheral surface of the inner cylindrical portion of the cover and the inner peripheral surface of the outer peripheral cylindrical portion of the case.

  In the fuel tank mounting part of the present invention, the inner cylinder part of the cover is held by the holding part of the case, and an O-ring is interposed between the cover and the case at the overlapping position of the holding part and the inner cylinder part. That is, the inner and outer peripheral surfaces of the inner cylindrical portion of the cover are in a state of facing the inner peripheral cylindrical portion and the outer peripheral cylindrical portion of the gripping portion on the entire circumference, respectively. And the holding part is formed from resin which is hard to swell with respect to fuel.

  Therefore, even if the inner cylinder portion is swollen by the fuel, the expansion is restricted by both the outer diameter side and the inner diameter side by the grip portion. Thereby, since the compressive force exerted on the O-ring does not decrease, it is possible to reliably prevent a decrease in sealing performance due to the O-ring.

  The tank mounting component of the present invention includes a cover, a case, and an O-ring. The cover is joined to the outer surface of the fuel tank. The cover is preferably bonded to the outer surface of the fuel tank by welding, and is preferably formed of high-density polyethylene that can be welded to the fuel tank. It is also preferable to form a gas barrier layer made of EVOH or the like on the surface that is not bonded to the fuel tank and that contacts the fuel.

  The cover includes a flange portion that is joined to the outer surface of the fuel tank, an outer cylinder portion that protrudes from one surface of the flange portion and extends to the outside of the fuel tank and is coupled to other components, and a fuel that protrudes from the other surface of the flange portion. And an inner cylinder portion that advances into the tank. In many cases, the other surface of the cover is formed with pipes connected to a canister or the like, an outer cylinder portion connected to other parts, and the like.

  The case is formed from a resin such as polyacetal or polyamide that is difficult to swell in fuel. This case is held by the cover. The case and the cover are formed separately from each other from the necessity of housing and assembling the valve body and are integrated by mechanical engagement means.

  The case includes a ring-shaped gripping part having an inner peripheral cylindrical part and an outer peripheral cylindrical part, and a cylindrical case body that advances from the gripping part into the fuel tank. The inner cylinder portion of the cover is gripped by this grip portion. That is, the inner and outer peripheral portions of the inner cylindrical portion are surrounded by the inner peripheral cylindrical portion and the outer peripheral cylindrical portion.

  The O-ring is disposed at the overlapping position of the grip portion of the case and the inner cylinder portion of the cover. It may be interposed between the inner cylinder part and the inner cylinder part, or may be interposed between the outer cylinder part and the inner cylinder part. However, when the inner cylinder portion swells, a force in the direction of expanding the diameter acts on the inner cylinder portion. Therefore, it is preferable to interpose an O-ring between the inner peripheral surface of the outer cylindrical portion and the outer peripheral surface of the inner cylindrical portion. If it does in this way, the compressive force with respect to an O-ring will increase more at the time of swelling, and a sealing performance will improve further.

  In the case where the cover has an outer cylindrical portion that protrudes from one surface of the flange portion and advances to the outside of the fuel tank and is coupled to other components, the other components are generally coupled to the outer cylindrical portion. For example, in the case of a backflow prevention valve, an oil supply pipe is inserted into the outer cylinder portion and is fastened by a clamp or the like from the outside. In such a case, it is desirable that the inner peripheral cylindrical portion of the case extends to the inner periphery of the outer cylindrical portion of the cover. By configuring in this way, the outer cylinder part of the cover is sandwiched between the oil supply pipe and the inner peripheral cylinder part, and even if the outer cylinder part swells, deformation can be prevented, and the fastening strength Can be kept high.

  For example, in the case of a backflow prevention valve, a valve body is provided on the case body of the case. In this case, the arrangement of the valve body is appropriately designed according to the application, such as being arranged in the case body of the case so as to be movable in the axial direction. Further, the shape, material, etc. of the valve body are not particularly limited, and are appropriately designed according to the application. An urging member such as a spring that urges the valve body in a predetermined direction can also be used.

  The valve body has a function of sealing fuel from flowing out from the case body of the cover to the outside of the cover at a predetermined time, and a seal portion is provided in a part thereof. The position of the seal portion varies depending on the application and design. For example, a seal seat that contacts and seals the front end surface of the case may be provided, or a seal surface that contacts and seals a seat portion provided in the middle of the case may be formed.

  If the seat part is formed in the case that is difficult to swell with respect to the fuel, the grip part that suppresses the trouble due to the fuel swelling of the cover and the seal part on which the valve body is seated can be integrally formed. The increase can be suppressed.

  Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples.

(Example 1)
FIG. 1 is a component configuration diagram of a fuel tank mounting component of the present embodiment, and FIG. This fuel tank mounting part is a backflow prevention valve, and includes a cover 1, a case 2, a valve body 3, an O-ring 4, and a spring 5.

  The cover 1 is formed of high-density polyethylene, and includes a flange portion 10, an outer cylinder portion 11 protruding from one surface of the flange portion 10, and an inner cylinder portion 12 protruding from the other surface of the flange portion 10. . A ring-shaped welded portion 13 that is welded to the fuel tank is formed at the peripheral edge of the flange portion 10 on the inner cylinder portion 12 side.

  The inner cylinder portion 12 is formed with three claw portions 14 at equal intervals in the circumferential direction. The claw portion 14 is elastically deformable in the radial direction by slits (not shown) formed in the inner cylinder portion 12 on both sides thereof.

  The case 2 is made of polyacetal which is hardly swellable with respect to fuel, and includes a ring-shaped gripping portion 20 composed of an inner peripheral cylindrical portion 20a and an outer peripheral cylindrical portion 20b, and a cylindrical storage portion 21 extending downward from the gripping portion 20. And have. The inner peripheral cylindrical portion 20a extends long to the opposite side of the accommodating portion 21. Further, as shown in FIG. 3, three engaging holes 22 are formed at equal intervals in the circumferential direction at the bottom of the gripping portion 20. When the claw portion 14 of the cover 1 is engaged with the engagement hole 22, the cover 1 and the case 2 are integrally coupled.

  As shown in FIG. 3, three ribs 23 are formed at equal intervals in the circumferential direction inside the housing portion 21 of the case 2, and the ends of the three ribs 23 have a cylindrical boss 25 having a through hole 24. It is connected to. Further, a stepped portion 26 is formed on the outer peripheral surface of the inner peripheral cylindrical portion 20a so as to face the outer peripheral cylindrical portion 20b. The O-ring 4 is engaged and held on the stepped portion 26.

  Further, a ring-shaped seal protrusion 27 protruding downward is formed at the tip of the accommodating portion 21, and a semi-cylindrical portion 28 is formed on the outer periphery of the seal protrusion 27 so as to cover approximately half of the circumferential direction. Yes. The half cylinder portion 28 regulates the direction of fuel discharge during refueling in a predetermined direction.

  The valve body 3 includes a valve body body 30 made of polyacetal, a rubber ring-shaped seal seat 31, a polyacetal-made perforated disk-shaped holding plate 32, and a cap 33. The valve body 30 includes a flange portion 30a, a shaft portion 30b protruding from the center of the flange portion 30a, and an inner cylinder portion 30c protruding from the flange portion 30a to the opposite side of the shaft portion 30a. Three claw portions 30d are formed in the inner cylinder portion 30c at equal intervals in the circumferential direction. The claw portion 30d can be elastically deformed in the radial direction by slits (not shown) formed in the inner cylinder portion 30c on both sides thereof.

  In the valve body 30, the inner cylinder portion 30 c is inserted through the center hole of the seal seat 31 and further inserted through the center hole of the holding plate 32. The claw portion 30d is engaged with the holding plate 32, whereby the seal seat 31 is sandwiched between the flange portion 30a and the holding plate 32. The outer diameters of the seal seat 31 and the holding plate 32 are larger than the diameter of the flange portion 30a, and the seal seat 31 is exposed in a ring shape on the outer periphery of the flange portion 30a.

  In the valve body 3 configured as described above, the shaft portion 30a is inserted into the through hole 24 of the boss 25 of the case 2 from below, and the spring 5 is inserted into the shaft portion 30a passing through the through hole 24. The spring 5 is held in a compressed state between the cap 33 and the three ribs 23 by fitting and fixing the cap 33 to the head of the shaft portion 30a. That is, in the state where no external force is applied, the valve body 3 is urged by the spring 5 in the direction approaching the cover 1, and the seal seat 31 exposed on the outer periphery of the flange portion 30 a is pressed against the seal protrusion 27 and sealed. Yes.

  In the backflow prevention valve of this embodiment, first, the case 2, the valve body 3 and the spring 5 are assembled, and the O-ring 4 is inserted from the tip of the inner peripheral cylinder portion 21 and is locked to the step portion 26. Next, the cover 1 is assembled and integrated. At this time, in the gripping portion 20, the O-ring 4 is compressed between the inner peripheral surface of the inner cylindrical portion 12 of the cover 1 and the outer peripheral surface of the inner peripheral cylindrical portion 20a, and the O-ring 4 is compressed between the cover 1 and the case 2. Seal the gap.

  Next, the case 2 containing the valve body 3 is inserted from the opening provided in the fuel tank, and the welded portion 13 of the flange portion 10 of the cover 1 is welded to the peripheral portion of the opening. And the outer cylinder part 11 of the cover 1 is press-fitted in the oil supply pipe, and is fastened by a clamp from the outer periphery. When refueling, the valve body 3 is pushed down against the urging force of the spring 5 due to the refueling pressure, and the seal between the seal seat 31 and the seal protrusion 27 is released, so that refueling is possible. After the refueling is stopped, the seal seat 31 and the seal protrusion 27 are pressed against each other by the urging of the spring 5, and the backflow of fuel into the case 2 is prevented.

  Even if the cover 1 is swollen by the fuel, since the inner cylinder portion 12 is gripped between the inner peripheral cylinder portion 20a and the outer peripheral cylinder portion 20b, the deformation in the radial direction is restricted. Therefore, it is possible to prevent the force for compressing the O-ring 4 from being lowered, and it is possible to reliably prevent the sealing performance from being lowered.

  Further, in this embodiment, the length of the inner peripheral cylindrical portion 20a of the case 2 is extended to the distal end portion of the outer cylindrical portion 11 of the cover 1. An oil supply pipe is fastened to the outer cylinder portion 11 by a clamp. That is, the outer cylinder portion 11 is sandwiched between the oil supply pipe and the inner peripheral cylinder portion 20a. Therefore, even if the outer cylinder portion 11 is swollen by the fuel, it is possible to reliably prevent the deformation in the radial direction and to prevent a problem that the fastening strength is lowered.

(Example 2)
FIG. 4 shows the fuel tank mounting part of this embodiment. This fuel tank mounting component is the same as that of the first embodiment except that the arrangement position of the O-ring 4 is different. The O-ring 4 is sandwiched between the outer peripheral surface of the inner cylindrical portion 12 of the cover 1 and the inner peripheral surface of the outer peripheral cylindrical portion 20b of the case 2.

  When the inner cylinder part 12 is swollen with fuel, a force in the diameter increasing direction acts on the inner cylinder part 12. Therefore, according to the valve device of the present embodiment, when the inner cylinder portion 12 swells with fuel, the O-ring 4 is compressed more and more between the inner cylinder portion 12 and the outer peripheral cylinder portion 20b. The nature is further improved.

(Example 3)
FIG. 5 shows the fuel tank mounting part of this embodiment. This fuel tank mounting part is a full tank detection valve, and is composed of a cover 1, a case 7, an O-ring 4, a spring 5, a float valve 6, and a bottom plate 8.

  The cover 1 is formed of high-density polyethylene and includes a flange portion 10 and an inner cylinder portion 12 that protrudes from the other surface of the flange portion 10. A ring-shaped welded portion 13 to be welded to the fuel tank is formed on the peripheral edge portion of the flange portion 10. The inner cylinder portion 12 is formed with three claw portions 14 at equal intervals in the circumferential direction. The claw portion 14 is elastically deformable in the radial direction by slits (not shown) formed in the inner cylinder portion 12 on both sides thereof. The cover 1 is formed with a pair of pipes 19 communicating with a canister or the like.

  The case 7 is made of polyacetal that is hardly swellable with respect to fuel, and includes a ring-shaped gripping portion 70 composed of an inner peripheral cylindrical portion 70a and an outer peripheral cylindrical portion 70b, and a bottomed cylindrical housing that extends downward from the gripping portion 70. Part 71. A communication opening 72 that communicates the upper and lower spaces with each other is formed on the upper end surface of the case 7, and a ring-shaped seat portion 73 that projects downward (to the fuel tank side) is formed at the peripheral edge of the communication opening 72. Is formed.

  Three engaging holes 74 are formed at equal intervals in the circumferential direction at the bottom of the gripping portion 70. When the claw portion 14 of the cover 1 is engaged with the engagement hole 74, the cover 1 and the case 7 are integrally coupled. An O-ring 4 is interposed between the outer peripheral surface of the inner cylindrical portion 70a and the inner peripheral surface of the inner cylindrical portion 12, and seals between the two.

  The float valve 6 is configured by vertically superposing a float body 60 and a valve body 61 so that they can move relative to each other. The float body 60 is placed on the bottom of the accommodating portion 21 via the spring 5. A seal projection 62 is formed on the upper part of the float valve 5. A bottomed cylindrical valve element 61 is held on the upper part of the float body 60 so as to be relatively movable in the vertical direction.

  The valve body 61 has a through hole 63 having a diameter smaller than that of the communication opening 72 in the center, and a seal surface is formed on the lower portion of the through hole 63 so that the seal protrusion 62 contacts and seals. Further, a ring-shaped valve main body 64 made of rubber is held on the upper part of the float main body 60, and the communication opening 72 can be sealed by the valve main body 64 coming into contact with the seat portion 73. A claw portion 65 extends downward and protrudes from the valve body 61 and engages with an engagement groove 66 formed on the outer peripheral surface of the float body 60. The engagement groove 66 is formed longer than the claw portion 65, and the valve body 61 is slightly movable in the vertical direction with respect to the float body 60. The seal projection 62 of the float body 60 seals the through hole 63 when the float body 60 and the valve body 61 move relative to each other in the direction approaching each other.

  A bottom plate 8 made of polyacetal is engaged and held at the tip of the accommodating portion 71 of the case 7. A through hole 80 penetrating the front and back is formed in the bottom plate 8 to allow the fuel to pass into the accommodating portion 71. A spring 5 is disposed between the lower end portion of the float body 60 and the bottom plate 8, and is held between the two by being held between the spring 5 and the bottom plate 8. However, the urging force is smaller than the total weight of the float body 60 and the valve body 61. In the air and in the gasoline vapor, the float body 60 and the valve body 61 press the spring 5 by its own weight, and the float body 60 The lower end surface is seated on the bottom plate 8.

  The float body 60 and the valve body 61 are made of polyacetal, and are configured so that the apparent specific gravity is smaller than that of gasoline due to its shape and the urging force of the spring 5 and floats on liquid gasoline. Then, when the valve body 61 rises as the float body 60 rises, the valve body 64 comes into contact with the seat portion 73 to seal the communication opening 72.

  In the fuel tank mounting component of the present embodiment, the inner cylinder portion 12 is gripped between the inner peripheral cylinder portion 70a and the outer peripheral cylinder portion 70b, so that deformation in the radial direction is restricted. Therefore, it is possible to prevent the force for compressing the O-ring 4 from being lowered, and it is possible to reliably prevent the sealing performance from being lowered.

  Further, in the fuel tank mounting part of the present embodiment, the diameter of the communication opening 72 is reduced, the valve body 61 is omitted, and the periphery of the seal projection 62 of the float body 60 abuts on the seat portion 73. You may comprise so that it may seal.

  The tank mounting component of the present invention is not limited to the backflow prevention valve described in the above embodiment, but can be used for a flow regulating valve for a breather circuit or an evaporation circuit.

It is a disassembled perspective view of the tank mounting component which concerns on one Example of this invention. It is sectional drawing of the tank mounting component which concerns on one Example of this invention. It is a top view of the case used for the tank mounting component which concerns on one Example of this invention. It is sectional drawing of the tank mounting component which concerns on 2nd Example of this invention. It is sectional drawing of the tank mounting component which concerns on 3rd Example of this invention.

Explanation of symbols

1: Cover 2: Case 3: Valve body 4: O-ring 5: Spring 10: Flange
11: Outer cylinder part 12: Inner cylinder part 13: Welding part
14: Claw 20: Grip 20a: Inner cylinder
20b: Outer cylinder part 21: Housing part 23: Rib
25: Boss 26: Step 27: Sealing ridge
30: Valve body 31: Seal seat 32: Holding plate

Claims (5)

A fuel tank mounting part attached to a resin fuel tank,
A cover having a flange portion joined to the outer surface of the fuel tank, and an inner cylinder portion protruding from the surface of the flange portion and extending into the fuel tank;
A ring-shaped gripping part that is formed of a resin that is hardly swellable with respect to the fuel, has an inner peripheral cylindrical part and an outer peripheral cylindrical part, and surrounds the inner and outer periphery of the inner cylindrical part with the entire circumference; A cylindrical case main body that advances into the tank, and a case that is held by the cover in a state where the gripping part grips the inner cylindrical part,
A fuel tank mounting component comprising: an O-ring interposed between the cover and the case at a position where the grip portion and the inner cylinder portion overlap.   The cover has an outer cylinder portion that protrudes from one surface of the flange portion, advances to the outside of the fuel tank, and is coupled to other components, and the inner peripheral cylinder portion extends to the inner periphery of the outer cylinder portion. Item 2. A fuel tank mounting part according to Item 1.   The fuel tank mounting component according to claim 1, wherein the O-ring is interposed between an outer peripheral surface of the inner cylinder portion and an inner peripheral surface of the outer cylinder portion.   The fuel tank mounting component according to claim 1, wherein a valve body movable in the axial direction is disposed in the case main body of the case.   The fuel tank mounting component according to claim 1 or 4, wherein a seat portion on which the valve body is seated is formed in the case.

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