JP3389600B2 - 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.

However, in such a fuel tank, since the deformation mode of the upper wall and the lower wall is different from the deformation mode of the side wall closing the upper wall and the lower wall, the deformation occurs when the upper wall and the lower wall are deformed. Different wall connecting portion connecting walls having different modes, that is, a connecting portion between the upper wall and the side wall, a connecting portion between the lower wall and the side wall, the different deformation modes interfere with each other and twist, In the worst case, the side wall may be broken locally. In addition, the transformation mode referred to here is
It is the amount of deformation inherent to the material, rigidity, shape, and thickness of the wall member forming the fuel storage chamber, the deformed shape (deformation direction), the plastic force, and the restoring force.

Incidentally, in the fuel tank having the above-mentioned structure, the connecting portion between the upper wall and the side wall and the connecting portion between the lower wall and the side wall each have a deformed side, and the number of the deformed sides corresponds to the corresponding portion. 1
It is an individual.

The present invention has been made to solve the above problems, and in a fuel tank having a fuel storage chamber that can be deformed according to the amount of fuel stored, the fuel tank is deformed when the fuel storage chamber is deformed. Provided is a fuel tank capable of preventing mutual interference between different deformation modes at different wall connecting portions connecting walls having different modes, preventing twisting at the different wall connecting portions, and preventing wall breakage. The purpose is to

[0008]

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 the fuel storage chamber has a plurality of walls connected to each other by a connecting portion. Walls that are connected to each other and are deformed in response to a change in the amount of fuel in the fuel storage chamber and that have different deformation modes are connected to each other via a different wall connection portion, and the different wall connection portion is connected to the fuel storage chamber. It is characterized by having deformation mode interference prevention means for preventing mutual interference between different deformation modes at the time of deformation.

According to the fuel tank of the first aspect of the invention, the fuel tank is provided for the different-wall connecting portion that connects the walls having different deformation modes and deforms each other according to the change of the fuel amount in the fuel storage chamber. The deformation mode interference prevention means prevents mutual interference between different deformation modes at the different wall connection portion when the fuel storage chamber is deformed.

Here, the fuel storage chamber is specifically
As in the second aspect of the invention, walls having different polygonal deformation modes, each of which is composed of an upper wall and a lower wall which are polygonal and are opposed to each other, and a peripheral wall which closes the upper wall and the lower wall via deformation mode interference preventing means. Are an upper wall, a lower wall and a peripheral wall.

Further, the fuel tank of the third invention is characterized in that, in addition to the first or second invention, the deformation mode interference prevention means is constituted to have two or more deformation sides.

According to the fuel tank of the third aspect, the deformation mode interference prevention means configured to have two or more deformation sides has walls having different deformation modes when the fuel storage chamber is deformed. The amount of deformation in the different deformation modes is adjusted while allowing the deformation of No. For this reason, mutual interference between different deformation modes at different wall connection portions is prevented, and the deformation stroke of the deforming wall (for example, the deformation stroke of the upper wall and the lower wall with respect to the peripheral wall) is increased, so that the fuel storage chamber The volume is increased and the fuel storage amount is increased.

Here, the deformation mode interference prevention means is
Specifically, as in the fourth aspect of the invention, it has a step shape or a bellows shape provided between walls having different deformation modes.

Various methods can be adopted as the method for manufacturing the fuel tank. For example, a parison (a tubular shaped plastic shape material used for blow molding) is inflated in a mold with compressed gas. Blow molding can be used to mold hollow objects.

By this blow molding, when a fuel tank, for example, a rectangular parallelepiped fuel tank in which different wall connecting portions connecting walls having different deformation modes are connected to each other has a single deforming edge, the connecting portion having the deforming edge is used as a fuel. It becomes the peripheral corner portion of the tank, for example, the parison of the upper wall, the lower wall and the peripheral wall other than the peripheral corner portion is extended toward the peripheral corner portion to form the connecting portion having the deformed side. The thickness of the connecting portion having the wall thickness becomes thinner than the wall thickness (for example, the upper wall, the lower wall, and the peripheral wall), but the deformation mode interference prevention means has a stepped shape. When manufactured by blow molding, the step shape has
Since it is a structure that is recessed inward as compared to the structure when it is made individual and approaches the parison side, for example, the amount of stretching the parison other than the above peripheral corner portions of the upper wall, the lower wall and the peripheral wall is reduced, and uneven thickness Is prevented from occurring. For this reason, the wall thickness of the fuel tank is made uniform, and the strength (buckling force) of the wall is increased. In addition, since the strength of the wall is increased in this way, the wall thickness can be reduced as compared with the case where only one deformation side is provided, and the volume of the fuel storage chamber is further increased to further increase the fuel storage amount. Will be increased. Therefore, as in the fifth aspect of the invention, it is preferable that the deformation mode interference prevention means has a recessed shape provided between the walls having different deformation modes. Further, the deformation mode interference preventing means may be an inclined wall provided between walls having different deformation modes as in the sixth aspect of the invention.

[0016]

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
A separation wall 6 (see FIG. 2) having a substantially rectangular parallelepiped shape is disposed in the internal space defined by the separation wall 6,
The internal space in the housing 4 includes a fuel storage chamber 5 inside the separation wall 6 and upper and lower space portions 61 a, 61 outside the separation wall 6.
and b. The separation wall 6 and the fuel storage chamber 5 constitute a fuel tank 70.

As shown in FIG. 2, the separation wall 6 which constitutes the fuel tank 70 has a basic shape in which the peripheral edge of a rectangular parallelepiped is recessed at a substantially right angle over the entire peripheral edge (hereinafter referred to simply as a substantially rectangular parallelepiped). Upper side step walls G1 to G4 that form a recess at the upper peripheral edge of the substantially rectangular parallelepiped shape.
And lower step walls H1 to H4 that form the recess at the lower peripheral edge of the substantially rectangular parallelepiped shape, a pair of substantially rectangular upper and lower walls 7 and 8 facing each other in the vertical direction, and the upper wall 7 and Lower wall 8
Of the four side walls (peripheral walls) 9a to 9d, which are substantially rectangular and connect (close) the corresponding sides to each other via the upper step walls G1 to G4 and the lower step walls H1 to H4, respectively. 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.

Further, as shown in FIGS. 3 and 4, the upper step walls G1 to G4 have concave shapes formed by vertical walls I1 to I4 and lateral walls J1 to J4, respectively. These vertical walls I1 to I
4 and the lateral walls J1 to J4 are respectively formed with connecting portions B1 to B4, and between the upper wall 7 and the vertical walls I1 to I4 of the upper stepped portion, a connecting portion A1 that connects them. ~ A
4 are formed respectively, and the connecting portions C1 to C connecting the lateral walls J1 to J4 of the upper step wall and the side walls 9a to 9d.
4 are formed respectively. In addition, in this embodiment, these connection parts A1-A4, C1-C4 are upper step walls G1-G4.
It is defined as included in.

Further, the lower step walls H1 to H4 have concave shapes constituted by vertical walls K1 to K4 and horizontal walls L1 to L4, respectively. Between the vertical walls K1 to K4 and the horizontal walls L1 to L4, connecting portions E1 to E4 are formed to connect them, respectively.
Between the lower wall 8 and the vertical walls K1 to K4 of the lower step walls, connecting portions D1 to D4 are formed, respectively, and between the lateral walls L1 to L4 of the lower step walls and the side walls 9a to 9d. Are formed with connecting portions F1 to F4, respectively. In addition,
In the present embodiment, these connecting portions D1 to D4, F1 to F
4 is defined as included in the lower step walls H1 to H4.

The separation wall 6 having the upper wall 7, the lower wall 8, the side walls 9a to 9d and the step walls G1 to G4 and H1 to H4 is
For example, a flat core part made of a copolymer resin of ethylene and vinyl or nylon is covered with a skin part made of high-density polyethylene on both sides to form a multi-layer structure, which has substantially rigidity and It can be transformed. A specific method for manufacturing the separation wall 6 will be described later.

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.
Defines the upper wall 7 and the lower wall 8 as step walls G1 to G4 and H1 to H4.
Corresponds to a connecting wall that connects each of them. Further, the upper wall 7, the lower wall 8, the side walls 9a to 9d and the step walls G1 to G4, H.
The shape of the separation wall 6 having 1 to H4 is appropriately selected according to the shape of the space in which the fuel tank 70 is to be installed.

As described above, inside the separation wall 6, the fuel storage chamber 5 having a substantially rectangular parallelepiped shape in the basic shape of the separation wall 6 is defined, and the fuel is supplied to the fuel storage chamber 5.
When the amount of fuel in the fuel storage chamber 5 exceeds the amount of fuel capable of maintaining a substantially rectangular parallelepiped shape (hereinafter referred to as a predetermined amount), the upper wall 7 and the lower wall 8 are separated from each other and bulge outward as shown in FIG. In addition to the curved deformation, the side walls 9a to 9d approach each other and are curved 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 FIG. 7, the upper wall 7 and the lower wall 8 approach each other and are curved and deformed inwardly, and the side walls 9a to 9d approach each other. It is bent and deformed so as to be depressed 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. 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.

Thus, the upper wall 7 and the lower wall 8 are curved and deformed so as to be largely warped in the vertical direction, and the side walls 9a to 9d are curved and deformed so as to be slightly warped inward. Therefore, the deformation modes of the upper wall 7 and the lower wall 8 are different from the deformation modes of the side walls 9a to 9d. The deformation mode referred to here is, as described above, the amount of deformation inherent to the material, rigidity, shape, and thickness of the wall member forming the fuel storage chamber 5, the deformed shape (deformation direction), the plastic force, It is the resilience.

By the way, as shown in FIG. 11, the shape of the separating wall 6 is the upper wall 7 without the step walls G1 to G4 and H1 to H4.
In the case of the separation wall 95 in which the lower wall 8 and the lower wall 8 are closed by the side walls 9a to 9d, that is, a rectangular parallelepiped shape, the number of deformed sides of the different wall connecting portion connecting the upper wall 7 and one side wall is changed. Side P
The number of deformation sides of the different-wall connecting portion between the lower wall 8 and one side wall is one of the deformation sides Q.

As described above, when the number of deformation sides of the different-wall connecting portions connecting the walls having different deformation modes is one, the upper wall 7 and the lower wall 8 are largely curved and deformed in the vertical direction.
Due to the small inward bending deformation of the side walls 9a to 9d, the different deformation modes interfere with each other on the deformation sides P and Q, and the deformation sides P and Q are twisted. In the worst case, the side walls are locally deformed. There is a risk of breaking.

However, in this embodiment, the upper step walls G1 to G4 are provided between the upper wall 7 and the side walls 9a to 9d, and the lower step part H1 is provided between the lower wall 8 and the side walls 9a to 9d. By providing H4 to H4, the number of deformation sides between the upper wall 7 and one side wall is increased to three (including the inner deformation side), and the lower wall 8 and one side wall are provided. The number of deformation sides between is increased to three. That is, FIG.
Corresponding to Fig. 3B, the description will be given for the side wall 9a. The deformation side between the upper wall 7 and the side wall 9a is defined by the connecting portions A1, B.
The number of deformation sides between the lower wall 8 and the side wall 9a is increased to three at the connecting portions D1, E1, and F1 as well as three at 1 and C1.

As described above, when the number of deformation sides of the different wall connecting portion connecting the walls having different deformation modes is increased (to two or more), the deformation sides are included when the separation wall 6 is deformed. As shown in FIGS. 6 and 8, the step walls G1 to G4 and H1 to H4 are deformed so as to allow the walls having different deformation modes to be deformed, and the deformation amounts according to the different deformation modes are adjusted. Therefore, mutual interference between different deformation modes on the step walls G1 to G4 and H1 to H4 is prevented.

Therefore, the connecting portions A1 to A having deformed sides
4, upper side step walls G1 to G4 including C1 to C4, and lower side step walls H1 to H4 including connecting portions D1 to D4 and F1 to F4 having deformation sides are different from each other for connecting walls having different deformation modes. They correspond to the wall connecting portions and to the deformation mode interference preventing means for preventing mutual interference between different deformation modes.

Referring again to FIG. 1, a fuel pipe 60 for supplying or discharging fuel to or from the fuel storage chamber 5 is connected to substantially the center of the lower wall 8 constituting the separation wall 6. This fuel pipe 60 is provided below the lower wall 8 with the fuel supply pipe 10.
And a fuel introduction pipe 20 connected to an auxiliary fuel tank 14 described later.

The fuel introduced from the fuel inlet (not shown) passes through the fuel supply pipe 10 and the fuel pipe 60, and the fuel storage chamber 5
And is supplied into the auxiliary fuel tank 14 via the fuel introduction pipe 20. Further, the fuel in the fuel storage chamber 5 is sucked into the auxiliary fuel tank 14 via the fuel pipe 60 and the fuel introduction pipe 20 when the fuel is discharged.

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.

Further, at a substantially central portion of the upper wall 7 constituting the separation wall 6, an evaporated fuel discharge pipe 11 for discharging gas in the fuel storage chamber 5, particularly evaporated fuel, to the outside of the fuel storage chamber 5 is a shutoff valve. It is connected via 12. This evaporated fuel discharge pipe 11 is
It has flexibility and allows bending deformation of the upper wall 7. Further, the shutoff valve 12 has the fuel liquid level in the fuel storage chamber 5
When it reaches, the evaporative fuel discharge pipe 11 is shut off to prevent the fuel from leaking to the outside of the fuel storage chamber 5.

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.

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, below the fuel pipe 60 of the lower wall 8 on the side wall 9c side, 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 dividing wall 18 extending substantially vertically upward is provided upright.
As shown in FIG. 9, 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 separation 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.

As shown in FIG. 1 and FIG. 10, the side walls 9a to 9d of the separation wall 6 are provided inside the entire periphery of the housing peripheral portion where the upper portion 2 and the lower portion 3 of the housing 4 are connected.
The upper portion 2 and the lower portion 3 form a void 21 having a height substantially the same as the height. In the void 21, the side walls 9a to 9d and the connecting portions 22 of the lateral walls J1 to J4 and L1 to L4 of the step walls connected to the side walls 9a to 9d are connected.
Is housed. Lateral walls J1 to J4 and L1 to L of this step wall
The connecting portion 22 of No. 4 is regarded as a part of the side wall, and hereinafter, the connecting portion 22 of the lateral walls J1 to J4 and L1 to L4 of the step walls and the side walls 9a to 9d are collectively referred to as a side wall corresponding portion 62.

In this way, the separation wall 6 has the side wall equivalent 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 slidable in the horizontal direction. The sandwiching portion 23 corresponds to a support member that supports the separation wall 6.

The side wall-corresponding portion 62 is displaced by sliding the holding portion 23 in the horizontal direction when the upper wall 7 and the lower wall 8 are curved and deformed. Further, when the upper wall 7 and the lower wall 8 are curved and deformed, the side walls 9a to 9d of the lateral walls J1 to J4 and L1 to L4 of the stepped wall.
The upward and downward displacement of the connecting part 22 with respect to 9d is very small. Therefore, as shown in FIG.
3, the upper wall 7, the lower wall 8 and the step walls G1 to G4, H1
Upward and downward curving deformation of ~ H4 is not suppressed.

As described above, the separation wall 6 is the side wall corresponding portion 6
2, the upper wall 7, the lower wall 8 and the step walls G1 to G4 and H1 to H4 are supported by the holding portion 23 of the housing 4 in FIG.
It is possible to bend and deform in the vertical direction according to the amount of fuel in the fuel storage chamber 5.

In order to dampen and cut the vertical or horizontal vibration input from the outside of the fuel storage chamber 5,
A vibration damping unit made of an elastic member may be additionally provided between the side wall corresponding portion 62 and the holding unit 23.

Next, a method of manufacturing the fuel tank 70 having the above structure will be briefly described. As described above, since the separation wall 6 forming the fuel tank 70 has a multilayer resin structure, the separation wall 6 is obtained by blow molding in this embodiment. In this blow molding, a parison (a tubular shaped plastic shape material used for blow molding) is fully inflated in a mold with a compressed gas to mold a hollow object.

By this blow molding, if a rectangular parallelepiped separating wall 95 shown in FIG. 11, that is, one deformed side of the different wall connecting portion is manufactured at one place, the connecting portion P having the deformed side is produced. , Q are the peripheral corners of the separation wall 95,
Since the parison of the upper wall 7, the lower wall 8 and the side walls 9a to 9d other than the peripheral corner portion is extended toward the peripheral corner portion to form the connecting portions P and Q having the deformed sides, the connecting portion P is concerned. , Q has an uneven thickness in which the wall thickness of each of the upper wall 7, the lower wall 8 and the side walls 9a to 9d is smaller than that of the upper wall 7, the lower wall 8 and the side walls 9a to 9d. 6, that is, the upper wall 7, the lower wall 8 and the side walls 9a to 9d are connected to the step walls G1 to G4.
When the substantially rectangular parallelepiped separation wall 6 connected through H1 to H4 is manufactured by blow molding, the step walls G1 to G4 and H1
˜H4 is a structure that is recessed inward as compared with the connecting portions P and Q of the separation wall 95 having the rectangular parallelepiped shape, and approaches the parison side, and therefore the peripheral edges of the upper wall 7, the lower wall 8 and the side walls 9a to 9d. The amount of stretching the parison other than the corners is reduced, and uneven thickness is prevented.

As described above, in this embodiment, the separation wall 6 has a uniform thickness, and the upper wall 7 and the lower wall 8 are the step walls G.
Side walls 9a to 9d supported through 1 to G4 and H1 to H4
The buckling strength of, that is, the buckling strength of the side wall corresponding portion 62 is strengthened.

For this reason, the side wall-corresponding portion 62 is attached to the holding portion 2
Even in the configuration of the present embodiment in which it is slidably supported in the horizontal direction by No. 3, the side wall corresponding portion 62 does not buckle.

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, FIG.
As shown in FIG. 6 and FIG. 6, the upper wall 7 is curved and deformed upward and the lower wall 8 is curved and deformed downward, and the side walls 9a to 9a.
d is curved and deformed inward, and step walls G1 to G4 and H1
To H4 are deformed while allowing the upper wall 7, the lower wall 8 and the side walls 9a to 9d to be curved and deformed. These curved deformations are
Without being restrained by the sandwiching portion 23 that supports the fuel tank 70, it gradually increases as the amount of fuel increases, the volume of the fuel storage chamber 5 increases, and the maximum amount of fuel is stored in the fuel storage chamber 5. It 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 amount of fuel increases, a larger amount of fuel is supplied. The amount is stored in the fuel storage chamber 5.

When the fuel amount increases, the step walls G1 to G
4, H1 to H4 are the upper wall 7, the lower wall 8 and the side walls 9a to 9d.
Of the stepped walls G1 to G4 and H1 to adjust the amount of deformation in different deformation modes while allowing the curved deformation of
Mutual interference between different deformation modes in H4 is prevented,
The step walls G1 to G4 and H1 to H4 are not twisted, and the side walls 9a to 9d are prevented from being broken.

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 the predetermined amount, as shown in FIG. 7 and FIG. Is curved and deformed downward, the lower wall 8 is curved and deformed upward, the side walls 9a to 9d are curved and deformed inward, and the step walls G1 to G4 and H1 to H4 are the upper wall 7, the lower wall 8, and the side wall. It deforms while allowing the curved deformations of 9a to 9d. These curving deformations are not suppressed by the sandwiching portion 23 that supports the fuel tank 70, but gradually increase as the amount of fuel decreases, and as shown in FIG.
The lower wall 8 and the lower wall 8 come into contact with each other at substantially the center thereof to be in close contact with each other, and further curving deformation is suppressed.

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

Even when the fuel amount is reduced, the step walls G1 to G1
G4, H1 to H4 are the upper wall 7, the lower wall 8 and the side walls 9a to 9
Since the step walls G1 to G4 and H1 to H4 are deformed while allowing the curved deformation of d, the side walls 9a to 9d are prevented from being broken. That is, the side walls 9a to 9d are not broken by the curved deformation of the upper wall 7, the lower wall 8 and the side walls 9a to 9d according to the increase or decrease of the fuel amount.

In the rectangular parallelepiped separating wall 95 shown in FIG. 11, the upper wall 7 will be described.
11 is curved and deformed upward to the position of the upper wall 7C shown by the dotted line in FIG. 11, and is curved and deformed downward to the position of the upper wall 7D shown by the dotted line, but the separation of the substantially rectangular parallelepiped shape of the present embodiment shown in FIG. In the wall 6, the number of deformed sides is increased as compared with the above rectangular parallelepiped shape, so that the upper wall 7 is the upper wall 7 of FIG.
It is curved and deformed to the position of the upper wall 7A shown by the dotted line in FIG. 10 above the position of C, and to the position of the upper wall 7B shown in the dotted line in FIG. 10 below the position of the upper wall 7D in FIG. . Of course, the same applies to the lower wall 8.

As described above, the deformation strokes of the upper wall 7 and the lower wall 8 in the case of the present embodiment in which the separating wall has a substantially rectangular parallelepiped shape are as follows.
Larger than the deformation stroke of. Therefore, the volume of the fuel storage chamber 5 is increased and the fuel storage amount is further increased, as compared with the case where the separation wall has a rectangular parallelepiped shape.

Moreover, as described above, since the wall thickness of the entire separation wall 6 is made uniform and the buckling strength is increased, the separation wall 6 is different from the separation wall 95 shown in FIG. Can be made thinner, the volume of the fuel storage chamber is further increased, and the fuel storage amount is further increased. Therefore, the fuel storage chamber 5
It is possible to maintain the maximum amount of fuel that can be stored in.

In this embodiment, the step walls G1 to G are formed.
Although the number of steps (number of steps) of H4 and H1 to H4 is one step, it is of course possible to have multiple steps.

FIG. 12 is a sectional view showing the peripheral portion of the fuel tank according to the second embodiment. In the separation wall 80 of the second embodiment which constitutes the fuel tank 70, the inclined walls M1 to M4 are replaced with the step walls G1 to G4 and H1 to H4 of the first embodiment.
The upper wall 7, the lower wall 8 and the side walls 9a to 9d are connected by N1 to N4. Therefore, the connecting parts A1 to 1 having the deformed sides
Upper inclined walls M1 to M4 including A4 and C1 to C4 and lower inclined wall step walls N1 to N4 including connecting portions D1 to D4 and F1 to F4 having deformation sides connect walls having different deformation modes. And different deformation mode interference prevention means for preventing mutual interference between different deformation modes. In addition, in FIG.
The inclined walls corresponding to 2 to M4 and N2 to N4 are omitted in the drawing.

According to the separating wall 80 thus constructed, the number of deformation sides between the upper wall 7 and one side wall is two, and the number of deforming sides between the lower wall 8 and one side wall is small. The number of deformation sides of is set to two. Explaining with reference to the side wall 9a shown in FIG. 12, the number of deformation sides between the upper wall 7 and the side wall 9a is two, that is, the connecting portions A1 and C1 having the deformation side, and the lower wall. The number of deformation sides between the side wall 8 and the side wall 9a is two, that is, the connecting portions D1 and F1 having the deformation sides.

That is, the number of deformed sides is increased as compared with the case where the rectangular parallelepiped separating wall 95 shown in FIG. 11 has one deformed side at a corresponding point.
Therefore, it goes without saying that the same action and effect as those of the first embodiment are achieved.

FIG. 13 is a sectional view showing the peripheral portion of the fuel tank according to the third embodiment. In the separation wall 90 of the third embodiment that constitutes the fuel tank 70, the upper wall 7 is formed by curved walls O1 to O4 and P1 to P4 that are curved inward instead of the step walls G1 to G4 and H1 to H4 of the first embodiment. The lower wall 8 and the side walls 9a to 9d are connected to each other. Therefore, the upper curved wall O including the connecting portions A1 to A4 and C1 to C4 having the deformed sides
1 to O4, connecting portions D1 to D4 and F1 to F having deformed sides
The lower curved walls P1 to P4 including 4 respectively correspond to different wall connecting portions connecting walls having different deformation modes, and
They correspond to deformation mode interference prevention means for preventing mutual interference between different deformation modes. Note that, in FIG. 13, curved walls corresponding to reference numerals O2 to O4 and P2 to P4 are omitted in the drawing.

In the separating wall 90 having such a structure, as in the second embodiment, the number of deformed sides between the upper wall 7 and one side wall is two, and the number of the deforming sides is lower. The number of deformation sides between one side wall is two. Therefore,
It goes without saying that the same action and effect as those of the second embodiment are obtained.

In the third embodiment, the curved walls O1 to O are provided.
Although 4, P1 to P4 are formed in one step, they may be formed in a wavy (concave and convex) shape to form multiple steps. According to this structure, the multi-stage curved wall becomes a so-called bellows.

Although the present invention has been specifically described based on its embodiments, the present invention is not limited to the above embodiments. For example, in the above embodiments, the holding portion 23 of the housing 4 may be used. Although the entire side wall-corresponding portion 62 is supported, only the four corner portions of the side wall-corresponding portion 62 (four corner portions of the fuel tank 70) may be supported. Even with this configuration, the corners
Since the side walls 9a to 9d and the upper and lower walls 8 and 9 have connection portions 9e to 9h that connect adjacent side walls and have the highest rigidity as compared with other portions and almost no deformation, deformation of the side walls 9a to 9d and the upper wall 7 and the lower wall 8 is suppressed. The side walls 9a to 9d, the upper wall 7, and the lower wall 8
Can be curved and deformed similarly to the above embodiment. In addition, since the corner portion has high rigidity as described above and has high buckling strength as described above, the fuel tank 70 can be favorably supported even with a 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 are opposed to each other, and the side walls 9a to 9d which close the upper wall 7 and the lower wall 8 as described above. The present invention is not limited to the fuel tank 70, but can be applied to all fuel tanks including a fuel storage chamber that can be deformed according to the amount of fuel stored.

[0078]

In the fuel tank according to the present invention, the deformation mode interference preventing means provided for the different wall connecting portion that deforms each other according to the change in the fuel amount in the fuel storage chamber and connects the walls having different deformation modes. However, when the fuel storage chamber is deformed, mutual interference of different deformation modes in the different wall connecting portion is prevented, so that twisting in the different wall connecting portion can be prevented and wall breakage 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.

3A and 3B are views for specifically explaining a connecting portion of the step wall of the fuel tank shown in FIG. 2, where FIG. 3A is a front view of the fuel tank and FIG.

4A and 4B are diagrams for explaining step walls, particularly vertical walls and horizontal walls, of the fuel tank shown in FIG. 2, in which FIG. 4A is a front view of the fuel tank, and FIG.

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

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

FIG. 7 is a perspective view showing a state of the fuel tank when the fuel is low.

FIG. 8 is a cross-sectional view taken along line XX of FIG.

FIG. 9 is a cross-sectional plan view showing an auxiliary fuel tank.

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

FIG. 11 is a detailed cross-sectional view similar to FIG. 10, showing a fuel storage device including the fuel tank when the basic shape of the fuel tank is a rectangular parallelepiped.

FIG. 12 is a sectional view showing a peripheral portion of a fuel tank according to a second embodiment.

FIG. 13 is a cross-sectional view showing a peripheral portion of a fuel tank according to a third embodiment.

[Explanation of symbols]

5 ... Fuel storage chamber, 6, 80, 90 ... Separation wall, 7 ... Upper wall,
8 ... Lower wall, 9a-9d ... Side wall (peripheral wall), 70 ... Fuel tank, A1-A4, B1-B4, C1-C4, D1-D
4, E1 to E4, F1 to F4 ... Connecting portion (deformed side), G1
~ G4, H1 to H4 ... Step walls, M1 to M4, N1 to N4
... Inclined walls, O1 to O4, P1 to P4 ... Curved walls.

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B60K 15/03 F02M 37/00 301

Claims (6)

(57) [Claims] 1. A fuel tank including a fuel storage chamber that is deformable according to the amount of fuel stored, wherein the fuel storage chamber is configured by connecting a plurality of walls to each other at a connecting portion. Walls that are deformed according to the change in the fuel amount and have different deformation modes are connected to each other through different wall connection portions, and the different wall connection portions are different from each other when the fuel storage chamber is deformed. A fuel tank having deformation mode interference prevention means for preventing mutual interference between the fuel tanks. 2. The wall forming the fuel storage chamber has an upper wall and a lower wall that are polygonal and face each other, and a peripheral wall that closes the upper wall and the lower wall via the deformation mode interference prevention means. 2. The fuel tank according to claim 1, wherein a deformation mode of the upper wall and the lower wall and a deformation mode of the peripheral wall are different from each other. 3. The fuel tank according to claim 1, wherein the deformation mode interference prevention means is configured to have two or more deformation sides. 4. The fuel tank according to claim 3, wherein the deformation mode interference prevention means has a step shape or a bellows shape provided between walls having different deformation modes. 5. The fuel tank according to claim 3, wherein the deformation mode interference prevention means has a recessed shape provided between walls having different deformation modes. 6. The fuel tank according to claim 3, wherein the deformation mode interference prevention means is an inclined wall provided between walls having different deformation modes.