JP2002321537A - Fuel tank for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simply structured fuel tank for vehicle with increased rigidity while preventing weight increase. SOLUTION: A lower tank panel 7 of the lower part of the fuel tank comprises an inclined sidewall 12 formed in the circumference of a bottom surface 9, a substantially vertical sidewall 13 formed continuous from the inclined sidewall 12, and a vessel 8 fastened to the bottom surface 9. A spot line C for fastening the vessel 8 is parallel to a substantially horizontal line of the inclined sidewall 12. A concave bead 14 and a convex bead 15 are arranged in a straight line. A maximum deformation part (a maximum sinking part) B is placed inside the area circumscribed by a plurality of spot welds A so that stress can be evenly distributed to all of the spot welds A. The maximum deformation part (the maximum sinking part) and a plurality of spot welds do not overlap each other, and the stress to the spot welds A is dispersed under vertical G, and thus durability of the lower tank panel with the vessel 8 fastened to it is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION Generally, a fuel tank to be mounted on an automobile is often determined after giving priority to a place where other parts are installed. The present invention relates to a fuel tank for a vehicle that is installed at a place where it does not interfere with other components.

[0002]

2. Description of the Related Art A fuel tank mounted on a vehicle is laid out so as not to interfere with other parts. For example, as shown in FIG.
A fuel pump 3 and a fuel filter 4 are installed, and a fuel tank 5 is attached to the lower rear part of the vehicle body.

As shown in FIG. 6, a fuel tank 5 mainly comprises
The outer shape is composed of an upper tank panel 6 and a lower tank panel 7, and a square tray-shaped vessel (auxiliary tank) 8 is built in. The vessel 8 is attached to the bottom surface 9 of the lower tank panel 7 by spot welding (welding location A), and the upper tank panel 6 and the lower tank panel 7 are seam-welded to flanges 10 formed on the respective outer circumferences to form a tank.
The lower tank panel 7 is formed in a concave shape by a bottom surface 9 and a peripheral wall 11 continuous with the bottom surface 9.

[0004] Since the fuel tank 5 is mounted so as not to interfere with other parts, the surface shape of the lower tank panel 7 is complicated, and the installation place of the vessel 8 is also limited. Ideally, the location of the vessel is good at the center of the bottom surface 9 of the lower tank panel 7.
Due to the shape described above, the vessel 8 has to be set so as to be offset from the central portion, and the rigidity is increased by other means.

[0005]

As shown in FIG. 7, the lower tank panel 7 has a substantially rectangular shape in a plan view, and the bottom surface is shifted to the left in accordance with a part of the left side wall (upper left position in the drawing). 9 is formed, the bottom surface 9 is formed in a substantially trapezoidal shape. When the vessel 8 is spot-welded to the bottom surface 9, the spot position A is conventionally made uniform.

The most severe condition of the strength of the fuel tank 5 in an actual vehicle is when a vertical G (pitch vibration) acts, as shown in FIG. At this time, the weight of the fuel in the fuel tank 5 acts on the bottom surface 9 of the lower tank panel 7 (a deformation line is indicated by a dotted line). That is, as shown in FIG. 7, when the vessel 8 is not arranged at the center of the lower tank panel 7 due to the positional relationship with the peripheral parts, the maximum position of the lower tank panel 7 in the conventional spot uniform arrangement at the time of the vertical G action is obtained. The deformed portion (pan sinking amount) B overlaps the spot portion A, which is not preferable in terms of strength. For this reason, conventionally, the strength has been increased by increasing the number of spots between the vessel 8 and the lower tank panel 7 or increasing the thickness of the vessel 8 and the lower tank panel 7. However, this countermeasure increases costs and weight, and other solutions are desired.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a fuel tank for a vehicle, which prevents weight increase and has a simple structure and has an enhanced mounting of the vessel.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, according to the present invention, a closed space is formed by joining an upper tank panel and a lower tank panel having a bottom surface and side walls. A fuel tank for a vehicle having an auxiliary tank fixed to the bottom surface of the closed space, wherein at least one of a plurality of welding points between the bottom surface and the auxiliary tank is closer to one of the side walls of the lower tank panel; A plurality of welding points between the lower tank panel and the auxiliary tank are arranged substantially in parallel with a substantially horizontal line on a side wall on one side of the lower tank panel. That is, the rigidity is improved by not adjusting the position of the spot welding to the location of the stress generated at or near the bottom surface of the lower tank panel.

According to a second aspect of the present invention, in the first aspect of the present invention, the lower tank panel is formed in a substantially rectangular shape in plan view, and at least one of the long side walls constituting the rectangle is closer to the auxiliary tank. The side wall is divided into a substantially vertical wall and an inclined side wall formed continuously with the substantially vertical wall, and the inclined side wall is formed so as to form an obtuse angle with respect to the substantially vertical wall.

[0010] The invention of claim 3 is claim 1 or claim 2.
In the invention, the bottom shape of the lower tank panel is:
Two sides sandwiching the acute-angled corner of both ends of the long side of the bottom surface connected to the inclined side wall are continuous with an arc having a large radius of curvature. When the lower tank panel is regarded as a rectangle in a plan view, the bottom shape is set to a shape closer to a rectangle by making the corresponding two sides and two corners the same.

According to a fourth aspect of the invention, there is provided a vehicle fuel tank in which an upper tank panel is joined to a lower tank panel having a bottom surface and side walls to form a closed space, and an auxiliary tank is fixed to the bottom surface of the closed space. A vertical bead is provided on an outer surface of the lower tank panel from a side wall to a bottom surface of the lower tank panel, and a convex bead is provided on a bottom surface on which the auxiliary tank is mounted. A fifth aspect of the present invention is characterized in that, in the fourth aspect of the present invention, the concave beads are formed on both ends of the convex beads to form one bead line.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings. The fuel tank attached to the vehicle body is formed by joining the upper tank panel and the lower tank panel. As shown in FIGS. 1 and 2, the lower tank panel 7 has a bottom surface 9. The inclined side wall 12 divided by the plane of FIG. 1 is formed, a substantially vertical wall 13 is formed continuously on the upper side of the inclined side wall 12, and a flange 10 for mounting an upper tank panel is formed on the upper edge of the substantially vertical wall 13. are doing.

In FIG. 1, a vessel (auxiliary tank) 8 is fixed to the bottom surface by spot welding A so as to be offset to the left inclined side wall 12. The spot position A (spot line C) on the side closer to the left inclined side wall 12a is arranged in parallel with the horizontal line of the inclined side wall 12a. The position of the bottom surface 9 of the lower tank panel 7 has a large width on the right side in FIG. 1, and the corners a and b at both ends of the long side of the bottom surface 9 connected to the inclined side wall 12 are the conventional corners a on the lower acute angle side in FIG. 'Loosen. That is, when the two sides sandwiching the corner a are continuous with an arc of the corner a having a large radius of curvature, and the lower tank panel 7 is regarded as a rectangle in a plan view, the bottom shape is the same as the corresponding two sides and two corners. To make the shape closer to a rectangle. The slope of the inclined side wall 12b connected to the arc is lower than that of the conventional one.

As shown in FIGS. 1 to 3, the lower tank panel 7 has a bottom surface 9 and an inclined side wall 12 divided by a plurality of planes around the bottom surface 9.
All the sloped side walls 12 are located in a frame (flange 10) formed by the upper edge of the lower side, and form a downward slope (90 degrees or less).

Further, on the outer surface of the lower tank panel 7,
A concave bead 14 extending from the intermediate portion of the substantially vertical wall 13 to the bottom surface 9 through the inclined side wall 12 forms a substantially rectangular lower tank panel 7.
Are formed at two corresponding positions along the longitudinal direction.
Since the concave bead 14 is formed by pressing, the concave bead 14 is protruded inside the lower tank panel 7. On the bottom surface 9, a convex bead 15 is formed on the outer surface of the lower tank panel 7, and the three bead portions are arranged on a straight line.

With the above configuration, first, the spot welded portion A of the vessel 8 is fixed to the bottom surface 9 of the lower tank panel 7.
Is aligned with the horizontal line of the adjacent side wall 12, the maximum deformed portion (maximum sinking) B can be brought to a position surrounded by a plurality of spot welds A.
This makes it possible to reduce the stress of the spot weld A by approximately 30%.

Further, the trapezoidal shape of the bottom surface 9 is enlarged to increase the radius of curvature of the corner a ', which is a narrow angle, to the radius of curvature of the corner a, virtually approaching a rectangle, and changing the shape of the bottom surface 9 of the lower tank panel 7. This makes it possible to move the maximum deformed portion (maximum sinking) B to the inside surrounded by the plurality of spot welds A, and to distribute the stress evenly to all the spot welds A. In addition, the peripheral wall is constituted by the inclined side wall 12 and the substantially vertical wall 13 so as to buffer when the upper and lower sides G act.

Further, by forming the concave bead 14 and the convex bead 15 passing through the central portion and the bottom surface 9 on the outer peripheral surface of the tank lower panel 7 and arranging them in a straight line, the surface rigidity of the side wall is strengthened, and In order to prevent sinking of the bottom surface 9 of the lower tank panel 7 when G acts. The end portions 14a of the two concave beads 14 shown in FIG. 3 can be marked and pinched because the concave beads 14 are arranged on a straight line, and are used for fixing a jig (for assembling the upper tank panel 6 and the lower tank panel 7 and performing seam welding). ) Can be used. In addition, the convex bead 1 is provided on the bottom surface 9.
The formation of 5 does not hinder the welding of the vessel 8.

Accordingly, the bottom surface 9 on which the vessel 8 of the lower tank panel 7 is installed is in a deformation mode in which the bottom surface 9 sinks when the upper and lower sides G act, but the arrangement of the spot welds A and the uneven beads 14 and 15 are combined. This increases the effect of increasing strength and improves durability. In addition, since there is no increase in spot welds and no other parts are used, weight reduction,
Cost can be reduced. Also, since there is no increase in the number of work steps, it can be manufactured at low cost.

[0020]

The present invention is as described above. According to the first aspect of the present invention, the plurality of welding points between the bottom surface near the side wall of the lower tank panel and the auxiliary tank are substantially horizontal lines on the side wall. The stress from the side wall is uniformly applied to the welding point, and the concentration of the stress on the bottom surface of the lower tank panel is reduced. This improves the durability of the weld.

According to the second aspect of the present invention, of the peripheral wall of the lower tank panel, the long side wall is divided into a substantially vertical wall and an inclined side wall formed continuously therewith, and the inclined side wall is formed with respect to the substantially vertical wall. Since they intersect at an obtuse angle, the stress is absorbed, and the stress applied to the welding point is evened. This makes it possible to suppress deformation of the lower tank panel. According to the third aspect of the present invention, the bottom surface of the rectangular shape of the lower tank panel is trimmed with an arc having a larger radius of curvature by giving priority to the sharper corners, and the bottom surface is made more rectangular. The position is moved so that it does not overlap with the welding point, thereby improving the durability of the lower tank panel. In the invention described in claim 4, the rigidity is improved by the concave bead and the convex bead formed from the side wall to the bottom surface of the lower tank panel, so that the effect of the vertical G can be reduced. Also, the concave bead can be used as a jig fixing bead, and the convex bead is formed on the outside of the bottom surface, so that the auxiliary tank can be easily welded to the inside of the bottom surface. According to the fifth aspect of the present invention, the concave beads are formed on both ends of the convex bead to form one bead line, thereby improving the rigidity of the lower tank panel.

[Brief description of the drawings]

FIG. 1 is a plan view of a lower tank panel of a fuel tank according to an embodiment of the present invention.

FIG. 2 is a perspective view of a lower tank panel shown in FIG.

FIG. 3 is a perspective view of the lower tank panel shown in FIG. 1 as viewed from below.

FIG. 4 is a plan view showing a modified example of the lower tank panel shown in FIG.

FIG. 5 is a schematic diagram showing a conventional fuel system of an automobile.

FIG. 6 is an exploded perspective view of a conventional fuel tank mounted on an automobile.

FIG. 7 is a plan view of a lower tank panel of the fuel tank shown in FIG.

FIG. 8 is a side view of a lower tank panel of the fuel tank shown in FIG.

[Explanation of symbols]

 Reference Signs List 5 fuel tank 6 upper tank panel 7 lower tank panel 8 auxiliary tank 9 bottom surface 12 inclined side wall 13 substantially vertical wall 14 concave bead 15 convex bead

Claims (5)

[Claims] 1. A closed space is formed by joining an upper tank panel and a lower tank panel having a bottom surface and a side wall,
In a vehicle fuel tank in which an auxiliary tank is fixed to a bottom surface of the closed space, at least a plurality of welding points between the bottom surface and the auxiliary tank, a bottom surface on a side closer to any one of side walls of the lower tank panel. A plurality of welding points with the auxiliary tank,
A fuel tank for a vehicle, wherein the fuel tank is arranged substantially in parallel with a substantially horizontal line of a side wall on one side of the lower tank panel. 2. The lower tank panel is formed in a substantially rectangular shape in plan view, and at least a side wall of the long side constituting the rectangle which is closer to the auxiliary tank is connected to a substantially vertical wall. 2. The fuel tank for a vehicle according to claim 1, wherein the inclined side wall is formed so as to form an obtuse angle with respect to the substantially vertical wall. 3. The bottom shape of the lower tank panel is characterized in that two sides sandwiching an acute-angled corner of both ends of a long side of the bottom surface connected to the inclined side wall are connected by an arc having a large radius of curvature. The vehicle fuel tank according to claim 1. 4. A closed space is formed by joining an upper tank panel and a lower tank panel having a bottom surface and side walls,
In a vehicle fuel tank having an auxiliary tank fixed to the bottom surface of the closed space, a vertical concave bead is provided on an outer surface of the lower tank panel from a side wall to a bottom surface of the lower tank panel, and a convex surface is provided on a bottom surface where the auxiliary tank is mounted. A vehicle fuel tank provided with a bead. 5. The vehicle fuel tank according to claim 4, wherein the concave beads are formed on both ends of the convex beads, and one bead line is formed.