JP2003072824A - Fuel tank seal structure - Google Patents

Abstract

(57) [Problem] To provide a fuel tank seal structure having low cost and waterproofness and fuel permeation prevention properties at low cost. SOLUTION: In a seal structure 1 in an opening 3a formed in a fuel tank main body 3 for incorporating a pump module 2a and the like, a seal used for a lid 4 for closing the opening 3a is made of a waterproof material (NBR). / PVC) and a fuel permeation prevention seal 6 made of a fuel permeation prevention material (FKM or the like).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel tank seal structure in an opening formed in a fuel tank body.

[0002]

2. Description of the Related Art Fuel tanks used in automobiles, etc.
There is a type in which a pump module for supplying fuel such as gasoline is housed in a fuel tank body. In this type of fuel tank, an opening is formed in the upper part of the fuel tank main body in order to install the pump module. This opening is closed by a lid to which the pump module is attached. In addition, in the seal structure in this opening, one annular seal is provided between the lid and the fuel tank main body, and this annular seal prevents fuel leakage from the fuel tank main body, and Prevents ingress of water. This annular seal is
It is molded from a blend material (hereinafter referred to as NBR / PVC) of acrylonitrile-butadiene rubber and polyvinyl chloride which is generally used as a fuel sealing material.

A seal structure shown in FIG. 5 will be described as an example of a conventional fuel tank seal structure. Figure 5
FIG. 8 is a front sectional view of a conventional fuel tank seal structure. In the seal structure 51 of the fuel tank 52, an opening 53a opened at an upper portion of the fuel tank main body 53 is closed by a lid 54, and the NB is provided between the fuel tank main body 53 and the lid 54.
An annular seal 55 formed of R / PVC is provided. At the periphery of the opening 53a of the fuel tank body 53,
The mounting portion 53b is welded, and a female screw portion 53d is engraved on the mounting portion 53b. The lid 54 has a disc-shaped lid 54a that covers the opening 53a and has the pump module 52a attached thereto, and the mounting portion 54b presses the outer periphery of the lid 54a from above. There is. A plurality of bolt insertion holes 54c are opened in the attachment portion 54b. The seal 55 has a fuel leakage prevention portion 55a having a substantially square shape in a cross-sectional view on the inner peripheral side and a thin plate-shaped waterproof portion 55b on the outer peripheral side, and a mounting portion 53b is provided at an intermediate portion thereof. An insertion hole 55c to be inserted is opened.

A bolt 56 having a plurality of flanges 57 is screwed into the mounting portion 54b to fasten the lid 54 to the fuel tank body 53, and the lid 54 seals the seal 55 to the fuel tank body 53. It is holding down. In this seal structure 51, in order to prevent the fuel from leaking to the outside, the fuel leak prevention portion 55a has the fuel tank main body 5
It is deformed by being sandwiched between the flange portion 53c of No. 3 and the outer end of the lid portion 54a of the lid 54, and the elastic force of the rubber against the deformation prevents the fuel from leaking from the fuel tank main body 53. Further, in this seal structure 51, in order to prevent corrosion of the iron fuel tank main body 53 (unpainted portion), the bolt 56, etc., and prevent water from entering the fuel tank main body 53, the waterproof portion 55b is formed. Is pressed against the fuel tank main body 53 by the pressing portion 54e at the outer end of the mounting portion 54b of the lid 54, and the end of the waterproof portion 55b is pressed against the fuel tank main body 53 to prevent water from entering from the outside. is doing.

[0005]

However, since the seal 55 is made of NBR / PVC, the NBR
Due to the characteristics of / PVC, the evaporated fuel in the fuel tank main body 53 permeates the seal 55, and the permeated evaporated fuel seals the seal 5.
After passing through 5, it is released into the atmosphere. Therefore, when a seal having a shape and function like the seal 55 is formed of a fluororubber (hereinafter, referred to as FKM) having a property of not permeating fuel, the FKM has a high unit price, and therefore, compared with the seal 55. It is very expensive. Also, FKM
Since the moldability is poor, it is difficult to mold the seal 55 into a complicated shape.

SUMMARY OF THE INVENTION An object of the present invention is to provide a fuel tank sealing structure which is waterproof and has fuel permeation preventive properties at low cost.

[0007]

A seal structure for a fuel tank according to claim 1 of the present invention, which has solved the above-mentioned problems, is a seal structure in an opening formed in a fuel tank main body, and the opening is closed. It is characterized in that the seal used for the lid body has a divided structure of a waterproof seal made of a waterproof material and a fuel permeation preventive seal made of a fuel permeation preventive material.

According to this seal structure for the fuel tank, in the seal used for the lid, the fuel permeation preventive seal is provided at the position where the fuel or the evaporated fuel coming out of the opening comes into contact, and the part where water from the outside enters By providing a waterproof seal on the inside, the fuel permeation preventive material with a use amount as small as possible can prevent the permeation of the fuel and the evaporated fuel and also prevent the intrusion of water. In addition, in this seal structure, by forming a portion having a complicated shape with a waterproof material, the shape of the fuel permeation preventive material can be made simple.

A fuel tank sealing structure according to a second aspect of the present invention is the fuel tank sealing structure according to the first aspect, wherein the waterproof material is NBR / PVC or hydrogenated acrylonitrile-butadiene rubber (hereinafter, hydrogenated). N
BR)), and the fuel permeation preventive material is fluororubber (FKM).

According to this fuel tank seal structure, the fuel permeation preventive seal is formed of FKM which is a high unit price material, and the waterproof seal is formed of NBR / PVC or hydrogenated NBR which is a low unit price material. Waterproofness and fuel permeation prevention can be realized at low cost.

The waterproof material is a material that is impermeable to water among the fuel resistant materials, and is, for example, NBR / PVC or hydrogenated NBR. Further, the fuel permeation preventive material is a material that does not allow fuel or vaporized fuel to pass through among the fuel resistant materials, and is, for example, FKM.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a fuel tank seal structure according to the present invention will be described below with reference to the drawings.

The fuel tank seal structure according to the present invention is
In order to reduce the usage of high-price fuel permeation preventive material as much as possible, the fuel permeation preventive seal is installed only in the parts where the fuel and evaporated fuel from the fuel tank body come into contact, and the waterproof seals are installed in other parts. The seal used for the lid that closes the opening of the fuel tank body is configured by the divided structure. In particular, in this fuel tank seal structure, FKM is used as the optimal material for preventing fuel permeation, and NBR / PVC or hydrogenated NBR is used as the waterproof material.

In the present embodiment, the fuel tank seal structure according to the present invention is applied to a pump tank type fuel tank seal structure in an automobile. The seal structure according to the present embodiment is provided with a fuel permeation preventive seal formed of FKM on the inner peripheral side between the fuel tank main body and the lid, and a waterproof seal formed of NBR / PVC on the outer peripheral side. Is provided.

Now, the structure of the seal structure 1 will be described with reference to FIGS. FIG. 1 is a front sectional view of a fuel tank seal structure. FIG. 2 is the waterproof seal of FIG. 1, (a) is a plan view, (b) is a front view, and (c) is a sectional view taken along the line AA in (a).
3 is the fuel permeation preventive seal of FIG. 1, (a) is a plan view, (b) is a front view, and (c) is a sectional view taken along line BB in (a). FIG. 4 is an exploded perspective view of the seal structure of the fuel tank. It should be noted that the pump module in the drawing shows a schematic external shape, and does not show a detailed shape that is not directly related to the present invention. Further, in FIG. 4, the pump module is omitted.

First, with reference to FIGS. 1 and 4, the structure of the fuel tank 2 necessary for describing the seal structure 1 will be described. The fuel tank 2 includes a fuel tank body 3 that stores fuel (gasoline), and an opening 3 a of the fuel tank body 3 is closed by a lid 4. Further, the fuel tank 2 is provided with a pump module 2a for pumping fuel, and the pump module 2a
Is built in the fuel tank body 3. Further, the fuel tank 2 has a waterproof seal 5 as a seal used in the lid body 4.
Also, a fuel permeation preventive seal 6 is provided. The waterproof seal 5 prevents water from entering from the outside, and the fuel permeation preventive seal 6 prevents fuel leakage and permeation of fuel and evaporated fuel. In the fuel tank 2, the waterproof seal 5 and the fuel permeation preventive seal 6 are arranged between the fuel tank main body 3 and the lid body 4, and the lid body is secured by the bolts 7, ... Through the seal rings 8 ,. 4 is fastened to the fuel tank body 3.

Next, the fuel tank body 3 will be described with reference to FIGS. 1 and 4. The fuel tank body 3 is made of iron and is formed in an appropriate shape according to the storage space (not shown) of the fuel tank 2 in the automobile. A circular opening 3a for accommodating the pump module 2a is opened in the upper portion of the fuel tank body 3, and a waterproof seal 5 and a fuel permeation preventive seal 6 are placed around the opening 3a. A peripheral flat portion 3b is formed. In addition, a flange portion 3c that obliquely rises from the peripheral flat surface portion 3b is formed on the peripheral edge forming the opening 3a.
Further, the peripheral flat portion 3b is welded with a mounting portion 30 which is a mounting portion with the lid body 4. The mounting portion 30 is formed by corrugating a donut-shaped iron plate, and has eight female screw portions 30a, into which the bolts 7, ... Are screwed into the protruding portions 30b ,.・ Is carved at approximately equal intervals. It should be noted that since the female screw portions 30a, ... Can be assembled in the wrong direction by setting them at equal intervals, the intervals are deliberately made unequal in order to eliminate mistakes during assembly.

Next, referring to FIGS. 1 and 4, the lid 4
Will be described. The lid 4 is made of resin and has an opening 3
a lid 40 for covering a, and a mounting portion 4 on the outer periphery of the lid 40.
1 and. The lid portion 40 has a disc shape, and has a diameter that covers a part of the peripheral flat surface portion 3b when the lid body 4 is attached to the fuel tank body 3. The end portion of the lid portion 40 is formed with a stepped engagement portion 40 a and engages with the end portion of the waterproof seal 5. The pump module 2a is integrally attached to the lower surface of the lid 40. On the other hand, the attachment portion 41 is made of thin annular iron and has a diameter that substantially covers the peripheral flat surface portion 3b when the lid body 4 is attached to the fuel tank body 3. The outer peripheral side of the mounting portion 41 has a slanted portion 4 bent from a bolt fastening flat surface portion 41a extending from the inner peripheral side.
A pressing portion 41c is formed continuously with 1b, and the pressing portion 41c presses the outer end portion of the waterproof seal 5. In addition, the bolt fastening flat surface portion 41a of the mounting portion 41,
Eight bolt holes 41d into which the bolts 7 ...
・ ・ Are opened at almost equal intervals. In the lid body 4, the lower surface on the inner peripheral side of the bolt fastening flat surface portion 41a presses the upper surface on the outer peripheral side of the lid portion 40 from above.

Next, referring to FIGS. 1, 2 and 4,
The waterproof seal 5 will be described. The waterproof seal 5 is a seal whose main purpose is to prevent entry of water from the outside, and is made of NBR / PVC as a material. The waterproof seal 5 is annular and has a diameter such that when assembled, the inner peripheral side has a diameter that engages with the engaging portion 40a of the lid 4, and the outer peripheral side is pressed to the pressing portion 41c of the lid 4. Have a diameter.

The inner peripheral side of the waterproof seal 5 has a peripheral flat surface portion 3b.
The side to be placed on is slightly long in cross-section
Is formed and engages with the engaging portion 40a of the lid portion 40. A semicircular protrusion 5b is formed on the upper surface of the engaging portion 5a when viewed in cross section, and when assembled, the protrusion 5b is formed.
Is pressed against the mounting portion 41 to be deformed, and is sealed by the elastic force of the protrusion 5b.

Further, a bolt fastening portion 5c is continuously formed above the engaging portion 5a of the waterproof seal 5, and the mounting portion 3 is formed.
Eight quadrangular holes 5d are provided so as to correspond to the zero convex portion 30b. As a result, the mounting portion 41 becomes the mounting portion 30.
It is tightened directly with bolts 7, ...

Further, on the outer peripheral side of the waterproof seal 5, a mounting portion 5f is formed continuously from the bolt fastening portion 5c to the bent slant portion 5e, and the mounting portion 5f is mounted on the peripheral flat surface portion 3b. And is pressed against the pressing portion 41c. A semicircular protrusion 5g is formed in a cross-sectional view at the outer end of the upper surface of the mounting portion 5f, and the protrusion 5g is formed when assembled.
Is pressed against the pressing portion 41c and deforms, and the protrusion 5g
Seal with the elastic force of.

NBR / PVC is a material that has been generally used as a fuel resistant material for automobiles, and is excellent in heat resistance, oil resistance, durability and the like under various environments in automobiles. It is also waterproof. Further, NBR / PVC is superior in moldability to FKM and has a low unit price.

Next, referring to FIGS. 1, 3 and 4,
The fuel permeation preventive seal 6 will be described. The fuel permeation preventive seal 6 is a seal whose main purpose is to prevent fuel leakage from the fuel tank body 3 and permeation of fuel and evaporated fuel, and is made of FKM. The fuel permeation preventive seal 6 is annular and has a diameter longer than the flange portion 3c of the fuel tank body 3 and shorter than the inner diameter of the waterproof seal 5 when assembled.

The fuel permeation preventive seal 6 has a thick H-shape when viewed in cross section, and has two protrusions 6a, 6a at the upper portion,
It has two protrusions 6b, 6b at the bottom. Protrusion 6a,
6a, 6b, 6b, when assembled, cover 40
It is pressed against and deformed and sealed by its elastic force.

As a fuel resistant material, FKM is excellent in heat resistance, oil resistance, durability and the like under various environments in automobiles, and is also excellent in the property of preventing permeation of fuel and evaporated fuel. By the way, the fuel permeation preventive seal 6 is
It is designed to have a simple shape in consideration of the formability of FKM and to be used in the smallest possible amount in consideration of the unit price of FKM.

The seal ring 8 will be described with reference to FIGS. 1 and 4. The seal ring 8 prevents water from entering from the outside and also functions as a washer.
It is molded from rubber such as BR / PVC. The seal ring 8 includes a washer having a U-shaped cross section and a rib-shaped seal member inside a washer.
It is used by inserting the bolt 7 into a.

Next, referring to FIGS. 1 to 4, the lid 4,
A procedure for assembling the waterproof seal 5 and the fuel permeation preventive seal 6 to the fuel tank body 3 will be described.

First, the fuel permeation preventive seal 6 surrounds the flange portion 3c of the fuel tank body 3 so as to surround the peripheral flat surface portion 3.
Place on b. Further, the waterproof seal 5 is placed on the peripheral flat surface portion 3b so as to surround the fuel permeation preventive seal 6. At this time, the waterproof seal 5 is placed so that the square holes 5d, ... Fit into the convex portions 30b ,.

Subsequently, the lid body 4 is attached to the engaging portion 40 of the lid portion 40.
It is placed on the waterproof seal 5 and the fuel permeation preventive seal 6 while engaging a with the engaging portion 5a of the waterproof seal 5. At this time, the lid portion 40 is placed on the fuel permeation preventive seal 6 while the engaging portion 40a engages with the engaging portion 5a. On the other hand, in the mounting portion 41, the bolt fastening flat surface portion 41a is in contact with the protrusion 5b of the waterproof seal 5, and the pressing portion 41c is in contact with the protrusion 5g of the waterproof seal 5.

Further, each seal ring 8 is inserted into each bolt 7, and the lid 4 is fastened to the female screw portion 30a of the mounting portion 30 by the bolt 7. The tightening with the bolts 7, ... Through the seal rings 8, ... Is performed at eight locations.

By tightening with the bolts 7, ..., The lid 4 is firmly fastened to the fuel tank body 3 through the waterproof seal 5 and the fuel permeation preventive seal 6.
At this time, the waterproof seal 5 and the fuel permeation prevention seal 6
Is pressed against the fuel tank body 3 by the lid 4.

Therefore, in the waterproof seal 5, the bolt fastening portion 5c functions only as a seal around the bolt fastening flat portion 41a of the lid 4 and the mounting portion 30 of the fuel tank main body 3 which is in direct contact with this portion. However, the lower surface of the engaging portion 5a and the lower surface of the mounting portion 5f are not attached to each other.
It is in close contact with the peripheral flat surface portion 3b. Further, in the waterproof seal 5, the protrusion 5b is crushed and deformed by the lid 40 of the lid 4, and the protrusion 5g is crushed and deformed by the pressing portion 41c of the lid 4. On the other hand, in the bolts 7, ..., The rib shape of the seal member inside the seal rings 8, ... Is vertically sandwiched and deformed. As a result, in the seal structure 1, the contact between the respective parts of the waterproof seal 5 and the protrusions 5b, 5
Since the invasion path of water from the outside is blocked by the elastic force of g, water does not enter the fuel tank main body 3 and the unpainted portion of the fuel tank main body 3 and the bolts 7 are not rusted.

On the other hand, in the fuel permeation preventive seal 6, the protrusion 6
The a, 6a, 6b and 6b are sandwiched between the lid portion 40 of the lid body 4 and the peripheral flat surface portion 3b of the fuel tank body 3 and are crushed and deformed. As a result, in the seal structure 1, the elastic force of the projections 6a, 6a, 6b, 6b of the fuel permeation preventive seal 6 blocks the fuel discharge passage from the fuel tank body 3, so that the fuel does not leak outside. . Further, in the seal structure 1, since fuel and vaporized fuel cannot permeate due to the material characteristics of the fuel permeation preventive seal 6, the fuel and vaporized fuel are not released into the atmosphere.

According to this seal structure 1, since the waterproof seal 5 and the fuel permeation preventive seal 6 are divided according to the purpose of sealing, it is possible to prevent the permeation of fuel or evaporated fuel with a very small amount of FKM. . Further, according to the seal structure 1, since the complex-shaped portion is molded by NBR / PVC, the shape of the fuel permeation preventive seal 6 made of FKM having poor moldability can be made simple.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-mentioned embodiments and can be carried out in various forms. For example, in the present embodiment, the fuel tank seal structure according to the present invention is applied to the fuel tank seal structure of an automobile, but it is also applicable to other fuel tank seal structures of special vehicles and the like. Further, although NBR / PVC is used as the waterproof material and FKM is used as the fuel permeation preventive material in the present embodiment, any material having the above-mentioned characteristics as the waterproof material or the fuel permeation preventive material may be used. However, other materials such as hydrogenated NBR may be used. Further, although the waterproof seal and the fuel permeation preventive seal are shaped as described above in the present embodiment, they may be shaped appropriately according to the shape of the lid and the shape around the opening of the fuel tank body.

[0037]

The fuel tank seal structure according to the first aspect of the present invention has a structure in which the waterproof seal and the fuel permeation preventive seal are divided, so that the amount of the fuel permeation preventive material used is reduced as much as possible. The permeation of evaporated fuel can be prevented, and the shape of the fuel permeation preventive seal can be simplified. Furthermore, in this seal structure, the waterproof seal can prevent water from entering from the outside, and the fuel permeation preventive seal can prevent fuel leakage.

In the fuel tank seal structure according to claim 2 of the present invention, the fuel permeation preventive seal is formed of FKM which is a high unit price material, and NBR / P which is a low unit price material.
Since the waterproof seal is formed of VC or hydrogenated NBR, it has both waterproofness and fuel permeation prevention at low cost.
Also, since the shape of the fuel permeation prevention seal can be simplified,
Even FKM, which has relatively poor moldability, can be easily molded.

[Brief description of drawings]

FIG. 1 is a front sectional view of a fuel tank seal structure according to an embodiment.

2 is a waterproof seal of FIG. 1, (a) is a plan view, (b) is a front view, (c) is A in (a)
FIG.

3 is a fuel permeation preventive seal of FIG. 1, (a) is a plan view, (b) is a front view, (c) is a sectional view taken along line BB in (a).

FIG. 4 is an exploded perspective view of a fuel tank seal structure according to the present embodiment.

FIG. 5 is a front sectional view of a conventional fuel tank seal structure.

[Explanation of symbols]

1 ... Seal structure 2 ... Fuel tank 2a ... Pump module 3 ... Fuel tank body 3a ... opening 4 ... Lid 5: Waterproof seal 6 ... Fuel permeation prevention seal

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kiyofumi Shida             1-4-1 Chuo Stock Market, Wako City, Saitama Prefecture             Inside Honda Research Laboratory F-term (reference) 3D038 CA07 CA15 CA22 CA25 CB01                       CC06                 3E084 AA05 AB04 BA02 CA01 CC03                       FA09 FD20 GA08 GB12 HA03                       HA04 HB09 HC03 HD01

Claims (2)

[Claims] 1. A seal structure for an opening formed in a fuel tank main body, wherein a seal used for a lid closing the opening is a waterproof seal made of a waterproof material and a fuel made of a fuel permeation preventive material. A seal structure for a fuel tank, characterized in that the seal structure is separated from the permeation-preventing seal. 2. The waterproof material is a blend material (NBR) of acrylonitrile-butadiene rubber and polyvinyl chloride.
/ PVC) or hydrogenated acrylonitrile-butadiene rubber (hydrogenated NBR), and the fuel permeation preventing material is fluororubber (FKM). 3. The fuel tank seal structure according to claim 1, wherein