JP3389601B2 - Fuel tank - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel tank for storing fuel.

[0002]

2. Description of the Related Art If there is a space above the liquid surface of a fuel in a fuel tank, vaporized fuel is generated and this vaporized fuel may be released to the atmosphere. Therefore, a fuel storage chamber for storing fuel is formed by a stretchable envelope film, and the envelope film is expanded and contracted according to the amount of fuel in the fuel storage chamber to generate evaporated fuel above the fuel liquid level in the fuel storage chamber. A fuel tank which is not provided is disclosed in, for example, Japanese Patent Application Laid-Open No. 8-170568. Specifically, the envelope includes an upper wall and a lower wall, and a bellows-shaped side wall connecting the upper wall and the lower wall to each other, and the lower wall of the envelope is a flat bottom wall of the housing. Attached to. Then, the upper wall of the envelope film moves up and down in the housing according to the amount of fuel in the fuel storage chamber, and the side wall expands and contracts as the upper wall moves up and down, and the upper wall moves up and down and the side wall expands and contracts. As a result, the volume of the fuel storage chamber increases or decreases.

[0003]

However, in the above fuel tank, since the lower wall which constitutes the fuel storage chamber is fixed to the bottom wall of the housing, the lower wall affects the amount of fuel stored in the fuel storage chamber. It is not displaced or deformed accordingly. Therefore, the amount of fuel that can be stored in the fuel storage chamber becomes maximum when the bellows-shaped side wall is maximally extended, and the fuel storage amount cannot be further increased with this structure.

Therefore, the Japanese Patent Application No. 1 filed by the applicant earlier.
No. 0-53739, in order to increase the amount of fuel that can be stored in the fuel storage chamber, the lower wall and the upper wall increase the volume of the fuel storage chamber as the amount of fuel stored in the fuel storage chamber increases. That is, there is disclosed a fuel tank having a deformable wall in which the lower wall is deformed downward and the upper wall is deformed upward. Further, in such a fuel tank, a predetermined portion such as a valve and a fuel passage for supplying / discharging fuel is connected to the upper wall and the lower wall by welding or integral molding.

Since the upper wall and the lower wall are deformable walls, the rigidity of a predetermined portion such as a valve or a fuel passage is higher than those of these. By connecting predetermined parts such as valves and fuel passages with high rigidity to the upper and lower walls by welding or integral molding, stress concentrates around the specified parts of the upper and lower walls when the fuel storage chamber is deformed. However, the upper wall and the lower wall may be locally bent.

The present invention has been made in order to solve such a problem, and in a fuel tank having a fuel storage chamber that can be deformed according to the amount of fuel stored, a predetermined value is provided when the fuel storage chamber is deformed. An object of the present invention is to provide a fuel tank capable of relieving stress concentration acting on a wall having a portion and preventing breakage of the wall.

[0007]

A fuel tank according to a first aspect of the present invention is a fuel tank having a fuel storage chamber that can be deformed according to the amount of fuel stored, and has a deformable wall that constitutes the fuel storage chamber. The deformable wall includes a portion having higher rigidity than the deformable wall in the wall surrounded by the peripheral edge of itself, and the fuel storage is provided in the wall around the high rigidity portion. It is characterized in that it is provided with stress absorbing means capable of relaxing concentration of stress acting on the deformable wall when the chamber is deformed.

In the fuel tank according to the first aspect of the invention, the deformable wall forming the fuel storage chamber has a rigidity higher than that of the deformable wall in the wall surrounded by the peripheral edge of itself. When the fuel storage chamber is provided with a high portion, the concentration of stress acting on the deformable wall when the fuel storage chamber is deformed is mitigated by the stress absorbing means provided around the highly rigid portion in the wall. Like

Here, the stress absorbing means is specifically a concave bead or a convex bead or an uneven bead formed on the wall as in the second invention.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of a fuel tank according to the present invention will be described below with reference to the accompanying drawings. In each figure, the same elements are designated by the same reference numerals, and overlapping description will be omitted.

The fuel tank of the present invention is used, for example, as a tank for storing the fuel to be supplied to the internal combustion engine. Of course, it can also be used simply as a tank for storing fuel.

FIG. 1 is a partial sectional view showing a fuel storage device having a fuel tank according to the first embodiment. The fuel storage device 1 includes a housing (also referred to as a tank shell) 4 that forms an outer shell of the fuel storage device 1. The housing 4 is formed of a rigid member such as metal or synthetic resin, and is composed of an upper part 2 and a lower part 3 which are vertically divided. The upper part 2 is curved upward and the lower part 3 is curved downward.
Are flanges 2a, 3 formed on the entire circumference of each peripheral edge.
They are hermetically connected to each other at a.

Upper part 2 and lower part 3 of the housing 4
In the internal space defined by, there are separation walls 6 forming a hexahedron.
(See FIG. 2), and the separation wall 6 allows the internal space in the housing 4 to be separated from the fuel storage chamber 5 inside the separation wall 6.
Then, the space above the separation wall 6 is separated into upper space 61a and lower space 61b. Then, the separation wall 6 and the fuel storage chamber 5
The fuel tank 70 is constituted by.

As shown in FIG. 2, the separation wall 6 constituting the fuel tank 70 has a basic shape of a substantially rectangular parallelepiped shape, and a pair of substantially rectangular upper and lower walls 7 and 8 facing each other in the vertical direction. , Four substantially rectangular side walls (peripheral walls) 9 that connect (close) the corresponding sides of the upper wall 7 and the lower wall 8 with each other.
a to 9d. These side walls 9a to 9d are connected to the edge parts of the other side walls adjacent to each other at both end parts thereof, and connecting parts 9e to 9h are formed between the side walls 9a to 9d, respectively.

These upper wall 7, lower wall 8 and side walls 9a-9d.
The separating wall 6 having, for example, a multi-layer structure in which both surfaces of a flat core part made of a copolymer resin of ethylene and vinyl or nylon are covered with a skin part made of high-density polyethylene, It is rigid and deformable.

The area of the upper wall 7 or the lower wall 8 is larger than the area of one side wall, and the rigidity of the upper wall 7 and the lower wall 8 is
It is smaller than the side walls 9a-9d.

Here, the upper wall 7 and the lower wall 8 are not limited to rectangular walls, but may be a pair of polygonal walls. Therefore,
The upper wall 7 and the lower wall 8 correspond to polygonal walls, and the side walls 9a to 9d.
Corresponds to a connecting wall that connects the upper wall 7 and the lower wall 8. The shapes of the upper wall 7, the lower wall 8 and the side walls 9a to 9d are appropriately selected according to the shape of the space where the fuel tank 70 is to be installed.

As described above, the fuel storage chamber 5 having a substantially rectangular parallelepiped shape in the basic shape of the separation wall 6 is defined inside the separation wall 6, and the fuel is supplied to the fuel storage chamber 5.
When the fuel amount in the fuel storage chamber 5 exceeds a fuel amount capable of maintaining a rectangular parallelepiped shape (hereinafter, referred to as a predetermined amount), the upper wall 7 and the lower wall 8 are separated from each other as shown in FIGS. The side walls 9a to 9d are curved and deformed so that the side walls 9a to 9d approach each other and are recessed inward.

That is, when the amount of fuel in the fuel storage chamber 5 exceeds a predetermined amount, the upper wall 7 is curved and deformed so as to warp vertically upward, and the lower wall 8 is curved and deformed so as to warp vertically downward, and the side wall. 9a to 9d are curved and deformed so as to warp in the horizontal direction and inward. In this way, the amount of fuel that can be stored in the fuel storage chamber 5 gradually increases.

On the other hand, when the fuel in the fuel storage chamber 5 is discharged,
When the amount of fuel in the fuel storage chamber 5 decreases below a predetermined amount, as shown in FIGS. 5 and 6, the upper wall 7 and the lower wall 8 approach each other and are curved and deformed so as to be recessed inward, and the side walls 9a to 9a.
They are curved and deformed so that d approaches each other and is recessed inward.

That is, when the amount of fuel in the fuel storage chamber 5 decreases below a predetermined amount, the upper wall 7 is curved and deformed so as to be curved downward, and the lower wall 8 is curved and curved so as to be curved upward, and the side wall 9 is formed.
The a to 9d are curved and deformed so as to warp in the horizontal direction and inward. Then, as shown in FIG. 6, the upper wall 7 and the lower wall 8 are recessed so as to be in close contact with each other. In this way, the amount of fuel that can be stored in the fuel storage chamber 5 gradually decreases.

The amount of deformation of the upper wall 7 and the lower wall 8 is larger than the amount of deformation of the side walls 9a-9d. Therefore, the upper wall 7 and the lower wall 8 correspond to large deformation surfaces, and the side walls 9a to 9d correspond to small deformation surfaces.

Referring again to FIG. 1, a fuel pipe (predetermined portion) 60 for supplying or discharging fuel to or from the fuel storage chamber 5 is connected to a substantially central portion of the lower wall 8 constituting the separation wall 6.
As shown in FIGS. 1 and 10, the fuel pipe 60 is formed integrally with the separation wall 6, and its rigidity is higher than that of the lower wall 8.

The lower wall 8 having the fuel pipe 60 is shown in FIG.
And, as shown in FIG. 10, a convex bead 76 surrounding the vicinity of the fuel pipe 60 is integrally molded (the overall shape is similar to a bead 75 described later shown in FIG. 9).
In particular, as shown in FIG. 10, the bead 76 has the upper wall 7 curved downward and the lower wall 8 curved upward, so that the upper wall 7 and the lower wall 8 come into contact with each other substantially at the center and are in close contact with each other. It is provided on the lower surface side of the close contact portion of the lower wall 8 when it becomes. The bead 76 relaxes the stress concentrated around the fuel pipe 60 of the lower wall 8 when the lower wall 8 is curved and deformed,
It corresponds to a stress absorbing means for the lower wall 8.

Further, as shown in FIG. 1, the fuel pipe 60 is branched below the lower wall 8 into a fuel supply pipe 10 and a fuel introduction pipe 20 connected to an auxiliary fuel tank 14 described later. It Then, the fuel introduced from the fuel introduction port (not shown) is supplied to the fuel storage chamber 5 via the fuel supply pipe 10 and the fuel pipe 60, and is also supplied into the auxiliary fuel tank 14 via the fuel introduction pipe 20. To be done. In addition, the fuel storage chamber 5
The fuel of the fuel pipe 60, the fuel introduction pipe 20
Is sucked into the auxiliary fuel tank 14 via the.

These fuel supply pipe 10 and fuel introduction pipe 2
No. 0, in the connecting portion with the fuel pipe 60, the pipe wall has a bellows shape and is expandable and bendable, and allows the lower wall 8 to be curved and deformed. In the present embodiment, the fuel introduction pipe 20 has a bellows shape over the entire length.

A shut-off valve (predetermined portion) 12 is welded to the upper wall 7 of the separating wall 6 at substantially the center thereof. The shutoff valve 12 shuts off the inside of the fuel storage chamber 5 from the outside when the liquid level of the fuel in the fuel storage chamber 5 reaches the shutoff valve 12, and its rigidity is higher than that of the upper wall 7.

As shown in FIGS. 1, 9 and 10, a convex bead 75 surrounding the vicinity of the cutoff valve 12 is integrally formed on the upper wall 7 having the cutoff valve 12. In this bead 75, the upper wall 7 is curved and deformed downward and the lower wall 8 is curved and deformed upward as shown in FIG.
The upper wall 7 and the lower wall 8 are provided on the upper surface side of the close contact portion of the upper wall 7 when the upper wall 7 and the lower wall 8 are in contact with each other at substantially the center and are in a close contact state. The bead 75 is for relieving the stress concentrated around the shutoff valve 12 of the upper wall 7 when the upper wall 7 is curved and deformed, and corresponds to a stress absorbing means for the upper wall 7.

Note that, in FIGS. 2 to 6, in order to facilitate understanding of the drawings, the components constituting the separating wall 6 such as the beads 75 and 76, the fuel pipe 60, the shutoff valve 12 and the like are omitted.

The shut-off valve 12 is connected to an evaporated fuel discharge pipe 11 for discharging the gas in the fuel storage chamber 5, especially the evaporated fuel, to the outside of the fuel storage chamber 5. The vaporized fuel discharge pipe 11 has flexibility and allows the upper wall 7 to be curved and deformed.

The evaporative fuel discharge pipe 11 is connected to the check valve 1
3. Connected to an intake passage (not shown) of the internal combustion engine via a charcoal canister (not shown) for temporarily adsorbing the evaporated fuel. The evaporated fuel adsorbed by the charcoal canister is purged into the intake passage according to the engine operating state of the internal combustion engine, and burned in the engine.

Further, the check valve 13 is the check valve 13
And the pressure in the evaporated fuel discharge pipe 11 between the shutoff valve 12 and
The valve is opened when the positive pressure exceeds a preset value, and the valve is closed when the pressure becomes lower than the preset positive pressure. Due to such an action of the check valve 13, gas is prevented from entering the fuel storage chamber 5 after the shutoff valve 12 is shut off once.

Further, on the inner wall surface of the upper portion 2 of the housing 4, there is provided a fuel gauge 71 for detecting the displacement position or movement amount of the upper wall 7 in the vertical direction and calculating the fuel amount in the fuel storage chamber 5. There is. The fuel gauge 71 is a pendulum type gauge, and calculates the fuel amount from the displacement angle of the pendulum.

On the lower portion 3 of the housing 4 and below the lower wall 8 on the side wall 9c side of the fuel pipe 60, the auxiliary fuel tank 14 for temporarily storing the fuel in the fuel storage chamber 5 is provided. Are placed. A fuel pump 16 for delivering the fuel in the auxiliary fuel tank 14 to a fuel injection valve (not shown) of an internal combustion engine via a fuel feed pipe 15 is arranged in the auxiliary fuel tank 14. The fuel pump 16 sucks the fuel through a filter 17 for filtering dust contained in the fuel, regulates the fuel pressure to a predetermined fuel pressure, and sends the fuel to the fuel injection valve.

On the lower wall 50 of the auxiliary fuel tank 14, a partition wall 18 extending substantially vertically upward is provided upright.
As shown in FIG. 7, the partition wall 18 is provided for the fuel pump 16
And a fuel chamber 16 disposed so as to surround the filter 17 and the fuel pump 16 and the filter 17 are formed, and the auxiliary fuel tank 14 is inclined and the fuel liquid level in the auxiliary fuel tank 14 is inclined. At times, it prevents the fuel around the filter 17 from being depleted. Therefore, the separation wall 18 corresponds to a fuel depletion prevention means.

As shown in FIG. 1, the upper surface of the upper wall 52 of the auxiliary fuel tank 14 and the lower portion 3 of the housing 4 are also shown.
The upper surface of the lower wall 8 of the lower wall 8 on the side wall 9a side of the fuel pipe 60 (hereinafter, simply referred to as a predetermined portion of the lower wall 3) is the upper surface when the lower wall 8 of the separating wall 6 is curved downward. The lower wall 8
And the lower surface of the upper part 2 of the housing 4 corresponds to
This matches the shape of the upper wall 7 when the upper wall 7 of the separation wall 6 is curved upward.

Therefore, the lower wall 8 is curved and deformed downward, and the upper wall 52 of the auxiliary fuel tank 14 and the lower portion 3 of the housing 4 are deformed.
When the upper wall 52 and the predetermined portion 3a of the lower portion 3 come into contact with the upper surface of the predetermined portion 3a of the lower wall 8, the lower wall 8 is restrained from being bent and deformed further downward. When the upper wall 7 is bent and deformed upward and abuts against the lower surface of the upper portion 2 of the housing 4, the upper portion 2 is moved upward beyond the upper wall 7 by limiting the bending to the predetermined size. Curving deformation of the upper wall 7 is restricted to a predetermined size.

Therefore, the lower wall 8 and the upper wall 7 of the separating wall 6 are
Due to the upper wall 52 of the auxiliary fuel tank 14, the predetermined portion 3a of the lower portion 3 of the housing 4, and the upper portion 2 of the housing 4, the upper wall 7 is prevented from being excessively curved and deformed beyond a preset allowable value. The lower wall 8 and the lower wall 8 are protected during the bending deformation. In addition, the shapes of the upper wall 52 of the auxiliary fuel tank 14 and the predetermined portion 3a of the lower portion 3 of the housing 4 match the downward curved shape of the lower wall 8, and the upper portion 2 of the housing 4
Since the shape of the upper wall 7 corresponds to the upward curved shape of the upper wall 7, the upper wall 7 and the lower wall 8 are further protected during the bending deformation. By thus protecting the upper wall 7 and the lower wall 8, damage to the fuel tank 70 is prevented.

Regarding the fuel supply to the fuel storage chamber 5 through the fuel supply pipe 10, the lower wall 8 of the separation wall 6 is the upper wall 52 of the auxiliary fuel tank 14 and the lower portion 3 of the housing 4. It abuts on the upper surface of the predetermined portion 3a, and the upper wall 7 of the separation wall 6
Is stopped when it comes into contact with the lower surface of the upper portion 2 of the housing 4. That is, the predetermined portion 3 of the upper wall 52 of the auxiliary fuel tank 14 and the lower portion 3 of the housing 4
The maximum storage amount of fuel in the fuel storage chamber 5 is determined by the upper part 2 of the housing 4a.

It is to be noted that fuel is increased with respect to a portion of the upper portion 2 of the housing 4 facing the bead 75, a lower portion 3 of the housing 4 and a portion of the upper wall 52 of the auxiliary fuel tank 14 facing the bead 76. The bead at time 75,
It is more preferable to provide a groove that avoids interference with 76.

Further, as shown in FIGS. 1 and 8, the heights of the side walls 9a to 9d of the separation wall 6 are provided inside the entire circumference of the housing peripheral portion where the upper part 2 and the lower part 3 of the housing 4 are connected. A void 21 having substantially the same height is formed by the upper portion 2 and the lower portion 3. In the void 21, the side walls 9a to 9d and the connecting portion 22 of the upper and lower walls 7 and 8 connected to the side walls 9a to 9d are housed. On this, the connecting portion 22 of the lower walls 7 and 8 is regarded as a part of the side wall,
Below, the connecting portion 22 of the upper and lower walls 7 and 8 and the side wall 9a.
9d are collectively referred to as a side wall equivalent portion 62, which corresponds to the peripheral edge portion of the separation wall 6 (fuel tank 70).

In this way, the separation wall 6 has a side wall corresponding portion 62.
Are sandwiched by the upper portion 2 and the lower portion 3 of the housing 4 and supported so as to be slidable in the horizontal direction with respect to the housing 4. That is, by the housing peripheral portion connecting the upper part 2 and the lower part 3 of the housing 4, the separation wall 6
The sandwiching portion 23 is configured to sandwich the side wall-corresponding portion 62 so as to be horizontally slidable (see FIG. 8). This sandwiching portion 23
Corresponds to a support member that supports the separation wall 6.

According to the fuel tank 70 constructed as described above, the fuel is supplied through the fuel supply pipe 10 into the separation wall 6 having a substantially rectangular parallelepiped shape as shown in FIG. When the fuel amount of No. 5 exceeds the above-mentioned predetermined amount,
As shown in FIG. 5, the upper wall 7 is curved and deformed upward, the lower wall 8 is curved and deformed downward, and the side walls 9a to 9d are curved and deformed inward. These bends are not suppressed by the sandwiching portion (support member) 23 that supports the fuel tank 70,
It gradually increases as the amount of fuel increases, and
Is increased and the maximum amount of fuel is stored in the fuel storage chamber 5. At this time, the auxiliary fuel tank 14 is also filled with fuel.

As described above, in the present embodiment, as compared with the fuel tank in which the upper wall 7 does not curve upward and the lower wall 8 does not curve downward as the fuel amount increases, more fuel is added. The amount is stored in the fuel storage chamber 5. Therefore, the maximum amount of fuel that can be stored in the fuel storage chamber 5 can be maintained.

On the other hand, when the fuel is discharged, the fuel pump 1
The fuel in the fuel storage chamber 5 is driven by the fuel pipe 60,
It is delivered to the fuel injection valve of the internal combustion engine through the fuel introduction pipe 20, the filter 17, and the fuel feed pipe 15. As the fuel amount in the fuel storage chamber 5 decreases, the upward curve of the upper wall 7, the downward curve of the lower wall 8 and the inward curves of the side walls 9a to 9d are gradually eliminated. When the amount of fuel in the fuel storage chamber 5 decreases to a predetermined amount, the separation wall 6 returns to the substantially rectangular parallelepiped shape shown in FIG.

Further, when the fuel is delivered from the fuel storage chamber 5 and the fuel amount in the fuel storage chamber 5 decreases below a predetermined amount, as shown in FIG. 5, the upper wall 7 bends downward due to negative pressure due to suction. While being deformed, the lower wall 8 is curved and deformed upward, and further, the side walls 9a to 9d are curved and deformed inward. These bends are not suppressed by the sandwiching portion 23 that supports the fuel tank 70, and gradually increase as the fuel amount decreases, and as shown in FIG. 6, the upper wall 7 and the lower wall 8 are Abutting and contacting at substantially the center, further curving deformation is suppressed.

As described above, in this embodiment, as compared with the fuel tank in which the upper wall 7 does not curve downward and the lower wall 8 does not curve upward as the fuel amount decreases, the decrease due to the curve. The volume of the space of the fuel storage chamber 5 is reduced by an amount corresponding to the volume of the stored fuel storage chamber 5. Therefore, the evaporated fuel is greatly reduced.

By the way, the upper wall 7 is connected to the shut-off valve 12 having higher rigidity than the upper wall 7, and the lower wall 8 is connected to the fuel pipe 60 having higher rigidity than the lower wall 8. 7
And when the lower wall 8 is curved and deformed, the shutoff valve 1 of the upper wall 7
There is a risk that stress concentrates on the periphery of the second wall 8 and stress concentrates on the periphery of the fuel pipe 60 on the lower wall 8, and the upper wall 7 and the lower wall 8 are locally bent.

However, in this embodiment, as shown in FIG. 1, FIG. 9 and FIG.
2 and beads 75, 76 around the fuel pipe 60 on the lower wall 8
Since the respective beads are provided, the beads 75 and 76 alleviate the stress concentration. Therefore, the upper wall 7 and the lower wall 8 do not break. In addition, particularly when the fuel is reduced, the upper wall 7 and the lower wall 8 are in close contact with each other at substantially the center thereof, and stress is particularly concentrated in the close contact portion, but in the present embodiment, the beads 75, 76 are used. But Figure 1
As shown in 0, since it is provided in the close contact portion, stress concentration in the close contact portion is relieved, and the upper wall 7 and the lower wall 8 are
Is prevented from being broken.

In this embodiment, the beads 75 and 76 are used.
Although it is a convex bead, it may be a concave bead or an uneven bead.

FIG. 11 shows a fuel tank according to the second embodiment. (A) is a plan view and (b) is a bottom view.

The fuel tank 77 of the second embodiment is the first
The difference from the fuel tank 70 of the embodiment is that, as shown in FIG. 11A, a bead 75 a that surrounds the bead 75 and a bead 75 b that surrounds the bead 75 a on the upper wall 7.
11B, a bead 76a surrounding the bead 76 and a bead 76b surrounding the bead 76a are further provided on the lower wall 8 as shown in FIG. 11B.

That is, the beads surrounding the shutoff valve 12 on the upper wall 7 are multi-stage beads 75, 75a, 75b, and the beads surrounding the fuel pipe 60 on the lower wall 8 are multi-stage beads 76, 76a, 76b. .

According to the fuel tank 77 of the second embodiment having such a configuration, the bead 75 on the side of the added upper wall 7 is added.
a, 75b, the beads 76a, 76b on the lower wall 8 side,
Since the stress concentration on the upper wall 7 and the lower wall 8 is gradually relaxed as compared with the first embodiment, breakage of the upper wall 7 and the lower wall 8 is further prevented. The stress concentration may be gradually relieved by appropriately changing the width and shape of each bead.

FIG. 12 is a plan view showing the fuel tank according to the third embodiment, and FIG. 13 is a front view of the fuel tank shown in FIG.

In the fuel tank 80 of the third embodiment, the uneven beads 81, 8 surrounding the shutoff valve 12 are provided.
2, 83 are provided on the upper wall 7 in this order from the vicinity of the shutoff valve 12 toward the connecting portion with the side walls 9a to 9d, and the uneven beads 91, 9 surrounding the fuel pipe 60 are provided.
2, 93 are provided on the lower wall 8 in this order from the vicinity of the fuel pipe 60 toward the connecting portions with the side walls 9a to 9d.

These beads 81 to 83 are integrally formed with the upper wall 7, and the beads 91 to 93 are integrally formed with the lower wall 8. The bead 81 near the shutoff valve 12 and the bead 91 near the fuel pipe 60 are the beads 75 and 76 of the first embodiment, respectively.
It is located in the same position as. Also, the outer beads 83,
93 are respectively located in the vicinity of the connecting portions with the side walls 9a to 9d. As shown in FIG. 12, the beads 81 to 83 of the upper wall 7 and the beads 91 to 93 of the lower wall 8 are arranged so as to exclude the positions of the diagonal lines L1 and L2 of the upper wall 7 and the lower wall 8 which are substantially rectangular. Each is formed. That is, the beads 81 to 83 of the upper wall 7 and the beads 91 to 93 of the lower wall 8 are diagonal lines L to each other.
Each of them is a discontinuous bead lacking the positions of 1 and L2. Note that, in FIG. 13, in order to facilitate understanding of the drawing, the bead in the range on the front side and the range on the back side sandwiching the shutoff valve 12 and the fuel pipe 60 in a substantially triangular range surrounded by the diagonal lines L1 and L2. 81-83, 91-93 are omitted, and only the beads 81-83, 91-93 in the range on the left and right sides in the drawing are drawn.

In this way, the beads 81 to 83 of the upper wall 7 and the beads 91 to 93 of the lower wall 8 are discontinuous beads lacking the positions of the diagonal lines L1 and L2. Even if the bead 81 in the vicinity and the bead 91 in the vicinity of the fuel pipe 60 of the lower wall 8 are extended to the positions of the diagonal lines L1 and L2 of the upper wall 7 and the lower wall 8 to be continuous, the upper wall 7 and the lower wall 8 can be obtained. But does not hinder the curved deformation of the beads 82, 83 of the upper wall 7 and the beads 92, 9 of the lower wall 8.
3, that is, the bead at a position relatively distant from the shutoff valve 12 and the fuel pipe 60, the diagonal lines L1 and L2 of the upper wall 7 and the lower wall 8
If the beads are extended to the position of and are continuous, the portions of the upper wall 7 and the lower wall 8 at the positions of the diagonal lines L1 and L2 project when the upper wall 7 and the lower wall 8 are curved and deformed, and the portions bend. This is because there is a risk.

The beads 81 to 83 and the beads 91 to 93 having the above-mentioned shapes are formed when the upper wall 7 and the lower wall 8 are curved and deformed.
The stress concentrated around the shutoff valve 12 of the upper wall 7 and the stress concentrated around the fuel pipe 60 of the lower wall 8 are respectively relaxed, and the beads 81 to 83 correspond to the stress absorbing means for the upper wall 7, 91 to 93 correspond to stress absorbing means for the lower wall 8. Also, the side walls 9a to 9d of the upper wall 7 and the lower wall 8
The beads 83 and 93 in the vicinity of the connecting portion between and relax the stress acting on the connecting portion between the upper wall 7 and the lower wall 8 and the side walls 9a to 9d when the upper wall 7 and the lower wall 8 are curved and deformed. Is provided for other purposes.

According to the fuel tank 80 of the third embodiment having such a configuration, the beads 81 to 83 of the upper wall 7 and the beads 91 to 93 of the lower wall 8 are not cut at the positions of the diagonal lines L1 and L2. Since each of the beads is a continuous bead, the upper wall 7 and the lower wall 8 are favorably curved and deformed according to the amount of fuel.

At this time, stress concentration acting on the upper wall 7 due to beads 81 to 83 provided around the shutoff valve 12 of the upper wall 7 and beads 91 to 93 provided around the fuel pipe 60 of the lower wall 8 Stress concentration acting on the lower wall 8 is alleviated,
Similar to the first embodiment, breakage of the upper wall 7 and the lower wall 8 is prevented. In addition, the stress acting on the connecting portions is relaxed by the beads 83, 93 near the connecting portions of the upper wall 7 and the side walls 9a to 9d of the lower wall 8. Therefore, the connecting portion is not twisted, and the side walls 9a to 9d are prevented from being broken.

Moreover, in this embodiment, the uneven beads 82, 83 of the upper wall 7 and the uneven beads 92 of the lower wall 8,
By 93, the outer peripheral portions of the upper wall 7 and the lower wall 8 from the central portion can be deformed to a greater extent than in the first embodiment. Therefore, when the amount of fuel increases, the upper wall 7 and the lower wall 8 have their outer peripheral portions largely curved and deformed upward and downward as compared with the first embodiment, respectively, as shown by phantom lines in FIG. Upper wall 7 and lower wall 8 due to curved deformation
The central part of is flattened as compared with the first embodiment.

Therefore, the stress concentration in the vicinity of the shutoff valve 12 of the upper wall 7 and in the vicinity of the fuel pipe 60 of the lower wall 8 is relaxed as compared with the first embodiment, and the volume of the fuel storage chamber 5 is increased as compared with the first embodiment. The fuel storage amount is increased.

Although the present invention has been specifically described based on its embodiment, the present invention is not limited to the above embodiment. For example, in the above embodiment, the holding portion 23 of the housing 4 can be used. Although it is configured to support the entire side wall equivalent part 62, four corners of the side wall equivalent part 62 (four corners of the fuel tanks 70, 77, 80).
It may be configured to support only. Even with such a configuration, the corner portion has the upper wall 7, the lower wall 8, and the connecting portions 9e to 9h that connect the adjacent side walls, and the rigidity thereof is highest as compared with the other portions, and almost no deformation occurs. Since the side walls 9a to 9d and the upper wall 7 and the lower wall 8 are not deformed, the side walls 9a to 9d are not suppressed.
The a to 9d and the upper wall 7 and the lower wall 8 can be curved and deformed similarly to the above embodiment. Further, since the corner portion has high rigidity as described above, the fuel tanks 70, 77, 80 can be favorably supported even with the configuration in which only the corner portion is supported. Furthermore, it is needless to say that the structure supporting only the corners can simplify the structure as compared with the above-described embodiment in which the entire side wall corresponding part 62 is supported.

The present invention is composed of the upper wall 7 and the lower wall 8 which are polygonal and face each other, and the side walls 9a to 9d which close the upper wall 7 and the lower wall 8 as described above. It is not applied only to the fuel tanks 70, 77, 80,
The present invention can be applied to all fuel tanks including a fuel storage chamber that can be deformed according to the amount of fuel stored.

[0066]

In the fuel tank according to the present invention, the deformable wall forming the fuel storage chamber has a portion having higher rigidity than the deformable wall in the wall surrounded by the peripheral edge of itself. When the fuel storage chamber is deformed, the stress absorbing means provided around the highly rigid portion in the wall relieves the concentration of stress acting on the deformable wall, so that the deformable wall is broken. Can be prevented. As a result, the reliability of the fuel tank can be improved.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing a fuel storage device including a fuel tank according to a first embodiment.

FIG. 2 is a perspective view showing a basic shape of a fuel tank.

FIG. 3 is a perspective view showing a state of the fuel tank when the fuel is full.

FIG. 4 is a sectional view taken along line XX of FIG.

FIG. 5 is a perspective view showing a state of the fuel tank when the fuel is low.

6 is a cross-sectional view taken along line XX of FIG.

FIG. 7 is a cross-sectional plan view showing an auxiliary fuel tank.

FIG. 8 is a detailed cross-sectional view showing an enlarged part A in FIG.

9 is a plan view of the fuel tank shown in FIG. 1. FIG.

10 is a cross-sectional view showing a state of the fuel tank of FIG. 9 when the fuel in the fuel tank is low.

FIG. 11 shows a fuel tank according to a second embodiment, (a) is a plan view and (b) is a bottom view.

FIG. 12 is a plan view showing a fuel tank according to a third embodiment.

13 is a front view of the fuel tank shown in FIG.

[Explanation of symbols]

5 ... Fuel storage chamber, 7 ... Upper wall (wall), 8 ... Lower wall (wall), 1
2 ... Shut-off valve (predetermined part), 60 ... Fuel pipe (predetermined part), 7
0, 77, 80 ... Fuel tank, 75, 75a, 75b,
76, 76a, 76b, 81-83, 91-93 ... Beads (stress absorbing means).

Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B60K 15/03 F02M 37/00

Claims (2)

(57) [Claims] 1. A fuel tank having a fuel storage chamber that is deformable according to the amount of fuel stored therein, comprising a deformable wall that constitutes the fuel storage chamber, and the deformable wall is In the wall surrounded by the peripheral edge, a portion having higher rigidity than the deformable wall is provided, and in the periphery of the portion having high rigidity in the wall, the deformable wall when the fuel storage chamber is deformed. A fuel tank comprising a stress absorbing means capable of relaxing concentration of acting stress. 2. The fuel tank according to claim 1, wherein the stress absorbing means is a concave bead, a convex bead or an uneven bead formed on the wall.