Fuel tank having a sub-tank provided on the inside of the fuel tank body

A fuel tank includes: a tank body including a bottom wall, a lateral wall and an upper wall, the tank body storing fuel in an interior surrounded by the bottom wall, the lateral wall and the upper wall; and a sub-tank storing a part of the fuel, the sub-tank including a wall portion, an opening portion and a post portion, the wall portion standing on the bottom wall and extending toward the upper wall. The opening portion is provided in the wall portion and is a portion in which the fuel flows. The post portion is provided integrally with the wall portion. The post portion is extended along a height direction of the wall portion from the bottom wall and is joined to the bottom wall and the upper wall.

INCORPORATION BY REFERENCE

The disclosure of Japanese Patent Application No. 2016-215588 filed on Nov. 2, 2016 including the specification, drawings and abstract is incorporated herein by reference in its entirety.

BACKGROUND

1. Technical Field

The disclosure relates to a fuel tank.

2. Description of Related Art

Japanese Patent Application Publication No. 2011-236752 discloses a fuel tank in which a sub-tank is fixed to a bottom portion. The sub-tank is configured as a container for storing fuel around a fuel pump.

SUMMARY

In a fuel tank in which the sub-tank is provided on the inside of a tank body, when the pressure (internal pressure) on the inside of the tank body is a positive pressure or a negative pressure relative to atmospheric pressure, there is a possibility that the sub-tank is inclined by the inclination of a bottom wall of the tank body and it becomes difficult to hold the fuel in the sub-tank. Here, it is conceivable to adopt a configuration of suppressing the deformation of the tank body by providing a pole on the inside of the tank body. However, in this configuration, since a different member from the sub-tank is provided on the inside of the tank body, the number of components increases. Therefore, the structure of the fuel tank is complicated. Thus, in the fuel tank in which the sub-tank is provided on the inside of the tank body, an improvement is required to suppress the deformation of the tank body in a simple structure.

The disclosure provides a fuel tank that can suppress the deformation of the tank body in a simple structure, in a configuration in which the sub-tank is provided on the inside of the tank body.

A fuel tank according to an aspect of the disclosure includes: a tank body including a bottom wall, a lateral wall and an upper wall, the tank body storing fuel in an interior surrounded by the bottom wall, the lateral wall and the upper wall; and a sub-tank storing a part of the fuel, the sub-tank including a wall portion, an opening portion and a post portion. The wall portion stands on the bottom wall and extending toward the upper wall. The opening portion is provided in the wall portion and is a portion in which the fuel flows. The post portion is provided integrally with the wall portion, the post portion is extended along a height direction of the wall portion from the bottom wall and is joined to the bottom wall and the upper wall.

In the aspect, the sub-tank in the interior of the tank body stores some of the fuel. When the internal pressure of the tank body is a positive pressure or a negative pressure relative to atmospheric pressure, the tank body expands or contracts. When the tank body expands or contracts, a tensile force or a compressive force is applied to the post portion joined to the bottom wall and the upper wall, but the post portion resists the tensile force or the compressive force. Therefore, it is possible to suppress the deformation of the tank body. The post portion is formed integrally with the wall portion and is extended along the standing direction of the wall portion, and therefore, it is possible to suppress the deformation of the tank body in a simple structure, compared to a configuration in which the post portion and the wall portion are separately provided.

In the aspect, the post portion may include a fragile portion where an area of a section orthogonal to an extending direction of the post portion is smaller than a section area of parts of the post portion other than the fragile portion.

According to the configuration, in the case where a tensile force or a compressive force in a previously set allowable range is applied to the post portion, the post portion resists the tensile force or the compressive force. On the other hand, in the case where a high load beyond the allowable range is input to the tank body, the fragile portion cannot resist the load so that the fragile portion is broken, when the load is transmitted from the tank body to the post portion. Since the fragile portion is broken in this way in the case where a high load is input to the tank body, an excessive stress is prevented from being concentrated on a joining part between the post portion and the bottom wall and a joining part between the post portion and the upper wall. Thereby, it is possible to suitably maintain the durability of the joining parts between the post portion and the tank body.

In the aspect, the post portion may include a displacement allowing portion configured to allow displacement of the upper wall relative to the bottom wall when a load from the upper wall of the tank body is applied.

According to the configuration, when the load from the upper wall of the tank body is applied and the upper wall is displaced relative to the bottom wall of the tank body, the displacement allowing portion of the post portion allows the displacement of the upper wall relative to the bottom wall. Thereby, an excessive stress is prevented from being concentrated on the joining part between the post portion and the bottom wall and the joining part between the post portion and the upper wall. Therefore, it is possible to suitably maintain the durability of the joining parts between the post portion and the tank body.

In the aspect, the post portion may have a cylindrical shape, and an inflow port into which the fuel in the sub-tank flows may be provided on a wall of the post portion.

According to the configuration, the fuel flows into the interior of the post portion through the inflow port, and the fuel is stored also in the interior of the post portion. Therefore, it is possible to increase the amount of the fuel that is stored in the sub-tank, compared to a configuration in which the post portion is solid.

In the aspect, when a direction from the bottom wall toward the upper wall is an upward direction and a direction from the upper wall toward the bottom wall is a downward direction, the post portion may include a flange that is provided at an end portion of the post portion in the upward direction and that is joined to the upper wall.

In the aspect, when a direction from the bottom wall toward the upper wall is an upward direction and a direction from the upper wall toward the bottom wall is a downward direction, the post portion may include a first rib at a portion below the fragile portion and a second rib at a portion above the fragile portion, the first rib extending in an up-down direction, the second rib extending in the up-down direction.

In the aspect, when a direction from the bottom wall toward the upper wall is an upward direction and a direction from the upper wall toward the bottom wall is a downward direction, the fragile portion may be positioned above an upper edge portion of the wall portion.

In the aspect, a plurality of the post portions may be provided on the wall portion in the fuel tank.

In the configuration, the plurality of post portions are formed on the wall portion. Therefore, when the tank body expands or contracts, it is possible to suppress the deformation of the tank body, compared to a configuration in which a single post portion resists the tensile force or the compressive force.

DETAILED DESCRIPTION OF EMBODIMENTS

First Embodiment

In the following, a fuel tank10according to a first embodiment will be described based onFIG. 1toFIG. 4B. The fuel tank10is mounted in an unillustrated vehicle. In each diagram, an arrow FR indicates a vehicle forward direction, an arrow W indicates a vehicle width direction, and an arrow UP indicates a vehicle upward direction. Hereinafter, when an upward or downward direction is merely described, the upward or downward direction means the upward or downward direction in a vehicle vertical direction. Further, when right or left is merely described, the right or left means the right side or left side in the vehicle width direction in a state where the vehicle is oriented in a travelling direction. A vehicle front-back direction, the vehicle width direction and the vehicle vertical direction are orthogonal to each other.

The fuel tank10shown inFIG. 1includes a tank body20in which a liquid fuel A is stored, and a sub-tank30that is provided in the interior of the tank body20. The fuel tank10is provided with a supply pipe12and a pump module14that feeds the fuel A in the interior of the tank body20, to an unillustrated engine of the vehicle, through a fuel inlet12A at the lower end of the supply pipe12.

As an example, the tank body20includes a bottom wall22and an upper wall24that are a pair of wall portions facing each other in the vehicle vertical direction, and a lateral wall26that connects an outer edge portion of the bottom wall22and an outer edge portion of the upper wall24in the vehicle vertical direction, and is formed in a hollow and nearly rectangular parallelepiped shape. In the tank body20, the fuel A is stored in the interior surrounded by the bottom wall22, the lateral wall26and the upper wall24. As an example, the tank body20is composed of a thermoplastic resin. Further, the tank body20is disposed such that a long direction of the tank body20is the vehicle width direction and a short direction of the tank body20is the vehicle front-back direction.

The bottom wall22is extended in the vehicle width direction and the vehicle front-back direction. In other words, the bottom wall22is disposed along a nearly horizontal direction. The upper wall24is extended in the vehicle width direction and the vehicle front-back direction, and is disposed along a nearly horizontal direction. Further, a through-hole28passing in the vehicle vertical direction is formed at a central portion of the upper wall24in the vehicle width direction and the vehicle front-back direction. A lid member18is provided on the upper side of the through-hole28of the upper wall24. The lid member18covers the through-hole28. On the lid member18, a through-hole19passing in the vehicle vertical direction is formed. The supply pipe12is inserted into the through-hole19and the through-hole28, with no space. The fuel inlet12A of the supply pipe12is disposed at a position that is higher than a lower wall32of the sub-tank30described later and that is lower than an upper surface of a wall portion34, at an interval from the lower wall32.

As an example, the sub-tank30shown inFIG. 2is composed of a thermoplastic resin, and includes the lower wall32, the wall portion34standing on an outer edge portion of the lower wall32, an opening portion36formed in the wall portion34, and post portions40formed on the wall portion34.

The lower wall32is extended in the vehicle width direction and the vehicle front-back direction, and as an example, is formed in a nearly oblong shape in which the length in the vehicle front-back direction is longer than that in the vehicle width direction, as viewed from the vehicle vertical direction. The lower wall32is placed on an upper surface22A (seeFIG. 1) of the upper side of the bottom wall22in the vehicle vertical direction. In other words, the lower wall32is disposed along a nearly horizontal direction. Here, a lower surface32A of the lower side of the lower wall32in the vehicle vertical direction contacts with the upper surface22A, but is not fixed to the upper surface22A. That is, between the lower surface32A and the upper surface22A, fixing means such as bonding and welding is not used.

The wall portion34stands straight along the vehicle vertical direction, in a state where the sub-tank30is provided in the interior of the tank body20(seeFIG. 1). In other words, the wall portion34stands on the bottom wall22in the interior of the tank body20. As an example, the wall portion34stands along the vehicle vertical direction, at both end portions in the vehicle width direction and a back end portion in the vehicle front-back direction, on the outer edge portion of the lower wall32.

Specifically, the wall portion34is configured by a right wall37, a left wall38and a back wall39. The wall portion34is formed in a nearly U-shape in which the front side in the vehicle front-back direction is opened, as viewed from the vehicle vertical direction. As an example, the heights of the right wall37, left wall38and back wall39in the vehicle vertical direction are set so as to be nearly the same height as each other. Further, as an example, the heights of the right wall37, left wall38and back wall39in the vehicle vertical direction are about ⅓ of the height of the internal space of the tank body20in the vehicle vertical direction (seeFIG. 1). Here, a surface of the upper end of the wall portion34in the vehicle vertical direction is referred to as an upper end surface34A.

The right wall37is formed in a nearly rectangular shape in which the length in the vehicle vertical direction is shorter than that in the vehicle front-back direction, as viewed from the vehicle width direction. The right wall37is extended from the front end of the lower wall32to the back end in the vehicle front-back direction. The left wall38is formed in a nearly rectangular shape in which the length in the vehicle vertical direction is shorter than that in the vehicle front-back direction, as viewed from the vehicle width direction. The left wall38is extended from the front end of the lower wall32to the back end in the vehicle front-back direction. The right wall37and the left wall38face each other in the vehicle width direction.

The back wall39is formed in a nearly rectangular shape in which the length in the vehicle vertical direction is shorter than that in the vehicle width direction, as viewed from the vehicle front-back direction. The back wall39is extended from the left end of the lower wall32to the right end in the vehicle width direction, and is connected to a back end portion of the right wall37and a back end portion of the left wall38.

As shown inFIG. 1, since the wall portion34stands in the interior of the tank body20, a space portion that is in the interior of the tank body20and that is below the center in the vehicle vertical direction is partitioned into a main storage portion21A outside the sub-tank30and an auxiliary storage portion21B inside the sub-tank30. That is, in the interior of the tank body20, some of the fuel A is stored in the auxiliary storage portion21B of the sub-tank30.

As shown inFIG. 2, the opening portion36is configured by a front end portion of the lower wall32, a front end portion of the right wall37and a front end portion of the left wall38, and is a part formed in a nearly U-shape in which the upper side is opened, as viewed from the vehicle front-back direction. In other words, the opening portion36is formed at the front end of the wall portion34. The opening portion36allows the flow (inflow and outflow) of the fuel A (seeFIG. 1). In the sub-tank30, when the height of the liquid surface of the fuel A is lower than the height of the wall portion34, the fuel A flows into the interior of the sub-tank30through the opening portion36.

As an example, the post portions40are formed integrally with the wall portion34, at a front end portion of the right wall37, a front end portion of the left wall38and a central portion of the back wall39in the vehicle width direction. That is, as an example, three (a plurality of) post portions40are formed. As an example, the three post portions40have the same configuration, except difference in disposing angle. Therefore, the description will be made for the post portion40formed integrally with the left wall38, and the description of the other two post portions40will be omitted.

As an example, the post portion40is configured to include an upstanding portion42, a lower flange44formed at the lower end of the upstanding portion42in the vehicle vertical direction, an upper flange46formed at the upper end of the upstanding portion42in the vehicle vertical direction, and a rib47and rib48for reinforcement. On the upstanding portion42, a fragile portion50is formed. Details of the fragile portion50will be described later.

The upstanding portion42is a plate-shaped portion having nearly the same thickness as the thickness of the wall portion34, and is extended along the standing direction of the wall portion34(the vehicle vertical direction) Here, the upstanding portion42is divided into a lower-side upstanding portion42A and an upper-side upstanding portion42B. The lower-side upstanding portion42A is a part of the upstanding portion42that is positioned in a range from the upper surface22A (seeFIG. 1) of the tank body20to the upper end surface34A of the wall portion34, and is a part where the wall portion34and the post portion40are integrated. On the other hand, the upper-side upstanding portion42B is a part that is positioned in a range on the upper side of the upper end surface34A.

The lower flange44is a part that projects from a lower end portion of the lower-side upstanding portion42A toward the outside of the wall portion34. The lower flange44is formed in a nearly semi-elliptical shape whose major axis direction is the vehicle width direction, as viewed from the vehicle vertical direction. As an example, the thickness of the lower flange44in the vehicle vertical direction is nearly the same as the thickness of the lower wall32in the vehicle vertical direction.

The upper flange46is a part that projects from an upper end portion of the upper-side upstanding portion42B toward the outside of the upper-side upstanding portion42B. Similarly to the lower flange44, the upper flange46is formed in a nearly semi-elliptical shape whose major axis direction is the vehicle width direction, as viewed from the vehicle vertical direction. As an example, the size of the upper flange46is nearly the same as the size of the lower flange44. In other words, as an example, the thickness of the upper flange46in the vehicle vertical direction is nearly the same as the thickness of the lower flange44in the vehicle vertical direction.

As an example, a lower surface44A shown inFIG. 1, which is the surface on the lower side of the lower flange44in the vehicle vertical direction, is thermally welded to the upper surface22A of the bottom wall22. Further, as an example, an upper surface46A, which is the surface on the upper side of the upper flange46in the vehicle vertical direction, is thermally welded to a lower surface24A, which is the surface on the lower side of the upper wall24in the vehicle vertical direction. The thermal welding is a technology for joining thermoplastic resins to each other, and includes also ultrasonic welding, high-frequency welding and the like. In this way, the post portion40is joined to the bottom wall22and the upper wall24. In other words, the post portion40is erected between the bottom wall22and the upper wall24along the vehicle vertical direction.

The rib47shown inFIG. 2is a plate-shaped portion whose thickness direction is the vehicle front-back direction. The rib47connects the upper surface of the lower flange44and the outer surface of the lower-side upstanding portion42A. Furthermore, the rib47is formed in a nearly right triangular shape, as viewed from the vehicle front-back direction. The rib47suppresses the deformation of the lower flange44and the lower-side upstanding portion42A. In other words, the rib47resists an external force that is applied to the lower flange44and the lower-side upstanding portion42A.

The rib48is a plate-shaped portion whose thickness direction is the vehicle front-back direction. The rib48connects the lower surface of the upper flange46and the outer surface of the upper-side upstanding portion42B. Furthermore, the rib48is formed in a nearly right triangular shape, as viewed from the vehicle front-back direction. The rib48suppresses the deformation of the upper flange46and the upper-side upstanding portion42B. In other words, the rib48resists an external force that is applied to the upper flange46and the upper-side upstanding portion42B.

The fragile portion50is formed on the upper-side upstanding portion42B. Specifically, as an example, the fragile portion50is formed at a nearly central portion of the upper-side upstanding portion42B in the vehicle vertical direction. In other words, the fragile portion50is formed above the center of the post portion40in the vehicle vertical direction. As an example, the fragile portion50is formed such that a part of the upper-side upstanding portion42B in the vehicle vertical direction is depressed toward the center in the vehicle width direction. Further, as an example, the fragile portion50is formed as a curved concave portion that is formed by gradually reducing the width of the upper-side upstanding portion42B in the vehicle front-back direction.

Furthermore, as an example, the fragile portion50is formed such that the depression amount of one side in the vehicle front-back direction is nearly the same as the depression amount of the other side. Here, the above description is the description for the fragile portion50on the left wall38. As for the fragile portion50on the back wall39, the vehicle front-back direction as the depression direction is replaced with the vehicle width direction.

As shown inFIG. 3, the fragile portion50is a part where an area S1of a section52orthogonal to the standing direction of the post portion40(the vehicle vertical direction) is smaller than an area S2of a section54that is of sections orthogonal to the standing direction of the upper-side upstanding portion42B and that has the largest section area. The section52and the section54are formed in a nearly rectangular shape, as viewed from the vehicle vertical direction. Here, the section54is an example of the different part.

The shape and size of the fragile portion50are set such that the fragile portion50can resist a compressive force or a tensile force to be applied to the joining portions between the post portion40and the tank body20(seeFIG. 1) when the compressive force or the tensile force is a force having a magnitude in an allowable range. Further, the shape and size of the fragile portion50are set such that not the joining portions but the fragile portion50is broken when the compressive force or the tensile force to be applied to the joining portions between the post portion40and the tank body20has a magnitude beyond the allowable range.

Next, operations and effects of the fuel tank10according to the first embodiment will be described.

In the fuel tank10shown inFIG. 1, when the fuel A flows from an unillustrated supply port into the interior of the tank body20, some of the fuel A is stored in the auxiliary storage portion21B, and the remaining fuel is stored in the main storage portion21A. Further, in the fuel tank10, when the internal pressure of the tank body20fluctuates, the tank body20deforms. For example, when the temperature of the interior of the tank body20rises to higher than the external temperature, the fuel A evaporates and the interior of the tank body20becomes a positive pressure state where the internal pressure of the tank body20is higher than the atmospheric pressure, the tank body20expands as shown inFIG. 4B.

On the other hand, when the fuel A is fed by the pump module14and the internal pressure of the tank body20becomes a negative pressure state where the internal pressure of the tank body20is lower than the atmospheric pressure, the tank body20contracts (is depressed) as shown inFIG. 4A. Examples of the case where the interior of the tank body20becomes a negative pressure state include a case where the temperature of the interior of the tank body20decreases to lower than the external temperature, for example, in addition to the case where the fuel A is fed.

In the fuel tank10, the post portion40is erected between the bottom wall22of the tank body20and the upper wall24, and when the tank body20expands or is depressed, the post portion40resists the tensile force or the compressive force. Thereby, it is possible to suppress the deformation of the tank body20. Particularly, at the portions where the post portion40is joined to the tank body20, it is possible to suppress the fluctuation of the interval between the bottom wall22and the upper wall24. Further, by the suppression of the deformation of the tank body20, it is possible to suppress the removing of the sub-tank30from the bottom wall22. Therefore, when the fuel A is fed from the sub-tank30by the pump module14, it is possible to reduce the amount of the fuel A that cannot be fed.

Here, the post portion40is formed integrally with the wall portion34and is extended along the standing direction of the wall portion34, and therefore, it is possible to suppress the deformation of the tank body20in a simple structure, compared to a configuration in which the post portion40and the wall portion34are separately provided.

Further, in the fuel tank10, the post portion40includes the lower flange44and the upper flange46, and therefore, the area (welding area) of the joining portions of the post portion40to the bottom wall22and the upper wall24is wider compared to a configuration in which there is no flange. Thereby, it is possible to suppress the deformation of the tank body20, compared to the configuration in which there is no flange.

As shown inFIG. 2, in the post portion40, the rib47and the rib48are formed, and therefore, it is hard for the upstanding portion42to be displaced relative to the lower flange44and the upper flange46. Thereby, in the fuel tank10, compared to a configuration in which the rib47and the rib48are not provided, it is possible to suppress the inclination of the post portion40relative to the standing direction (the vehicle vertical direction), and therefore, it is possible to suppress the deformation of the tank body20to which the post portion40is joined.

Further, in the fuel tank10, the plurality of (three, as an example) post portions40are formed on the wall portion34. Therefore, when the tank body20expands or contracts, it is possible to suppress the deformation of the tank body20, compared to a configuration in which a single post portion40resists the tensile force or the compressive force.

Next, a case where a high load is input to the fuel tank10shown inFIG. 1, for example, due to collision of the vehicle will be described. In the fuel tank10, in the case where a high load beyond the allowable range is input to the tank body20, the fragile portion50(seeFIG. 2) cannot resist the load so that the fragile portion50is broken, when the load is transmitted from the tank body20to the post portion40. In the fuel tank10, since the fragile portion50is broken in this way in the case where a high load is input to the tank body20, an excessive stress is prevented from being concentrated on the joining part between the post portion40and the bottom wall22and the joining part between the post portion40and the upper wall24. Thereby, it is possible to suitably maintain the durability of the joining portions between the tank body20and the post portion40.

Second Embodiment

Next, a fuel tank10according to a second embodiment of the disclosure will be described. Here, for components and portions having the same functions as those of the above-described fuel tank10(seeFIG. 1) according to the first embodiment, reference characters identical to the reference characters used in the first embodiment are assigned, and the description will be omitted.

The fuel tank10according to the second embodiment includes the tank body20(seeFIG. 1) and a sub-tank60(seeFIG. 5). As an example, the sub-tank60is composed of a thermoplastic resin, and includes the lower wall32, the wall portion34, the opening portion36, and post portions70(seeFIG. 5).

As shown inFIG. 5, the post portions70, as an example, are formed integrally with the wall portion34, at the front end portion of the right wall37, the front end portion of the left wall38and the central portion of the back wall39in the vehicle width direction. That is, as an example, three post portions70are formed. As an example, the three post portions70have the same configuration, except difference in disposing angle. Therefore, the description will be made for the post portion70formed integrally with the left wall38, and the description of the other two post portions70will be omitted.

As an example, the post portion70is configured to include an upstanding portion72, the lower flange44formed at the lower end of the upstanding portion72in the vehicle vertical direction, and the upper flange46formed at the upper end of the upstanding portion72in the vehicle vertical direction. On the upstanding portion72, a displacement allowing portion80is provided. Details of the displacement allowing portion80will be described later. The post portion70is joined to the bottom wall22and the upper wall24(seeFIG. 1). In other words, the post portion70is erected between the bottom wall22and the upper wall24along the vehicle vertical direction.

As shown inFIG. 6, the upstanding portion72is extended along the standing direction of the wall portion34(seeFIG. 5). Here, the upstanding portion72is divided into a lower-side upstanding portion72A, a connecting portion72B and an upper-side upstanding portion72C. The displacement allowing portion80is provided at a part where the upper end of the lower-side upstanding portion72A and the lower end of the connecting portion72B are jointed and a part where the upper end of the connecting portion72B and the lower end of the upper-side upstanding portion72C are jointed.

The lower-side upstanding portion72A is a part of the upstanding portion72that is extended from the upper surface22A (seeFIG. 1) to the displacement allowing portion80above the upper end surface34A (seeFIG. 5) in the vehicle vertical direction, and is a part where the wall portion34(seeFIG. 5) and the post portion70are integrated. The lower-side upstanding portion72A is a plate-shaped portion having nearly the same thickness as the thickness of the wall portion34. Furthermore, a concave shape portion73in which the upper side is opened as viewed from the vehicle width direction is formed at the upper end of the lower-side upstanding portion72A. Two jointing portions74are formed at both outer sides of the concave shape portion73in the vehicle front-back direction. Each jointing portion74is formed in a nearly circularly cylindrical shape, as viewed from the vehicle front-back direction. In each jointing portion74, a through-hole74A that passes through the jointing portion74in the vehicle front-back direction is formed.

As an example, the connecting portion72B is configured as a member that integrally includes a jointed portion75, a columnar portion76and a jointed portion77.

The jointed portion75is formed in a nearly circularly cylindrical shape, as viewed from the vehicle front-back direction. In the jointed portion75, an unillustrated through-hole that passes through the jointed portion75in the vehicle front-back direction is formed. The length of the jointed portion75in the vehicle front-back direction is a length that allows the jointed portion75to be contained in the concave shape portion73.

The columnar portion76is extended in a columnar shape to the upper side in the vehicle vertical direction, from a part that is a top portion of a peripheral wall of the jointed portion75as viewed from the vehicle front-back direction and that is a central portion of the jointed portion75in the vehicle front-back direction. Further, the upper end of the columnar portion76is connected to a part that is a bottom portion of a peripheral wall of the jointed portion77as viewed from the vehicle front-back direction and that is a central portion of the jointed portion77in the vehicle front-back direction. Specifically, the columnar portion76is configured by a nearly circularly columnar axis portion76A that extends in the vehicle vertical direction and four ribs76B that connect an outer peripheral surface of the axis portion76A and the jointed portions75,77. The four ribs76B are disposed at regular intervals in the peripheral direction of the axis portion76A. Each rib76B is formed in a nearly right triangular shape, as viewed from the peripheral direction of the axis portion76A.

The jointed portion77is formed in a nearly circularly cylindrical shape, as viewed from the vehicle width direction. In the jointed portion77, an unillustrated through-hole that passes through the jointed portion77in the vehicle width direction is formed. As an example, the length of the jointed portion77in the vehicle width direction is nearly the same as the length of the jointed portion75in the vehicle front-back direction. The jointed portion77is disposed so as to be nearly orthogonal to the jointed portion75, as viewed from the vehicle front-back direction.

The upper-side upstanding portion72C is a part that is positioned in a range on the upper side of the displacement allowing portion80. The upper-side upstanding portion72C is a plate-shaped portion having nearly the same thickness as the thickness of the wall portion34(seeFIG. 5). Furthermore, the upper-side upstanding portion72C is disposed so as to be nearly orthogonal to the lower-side upstanding portion72A, as viewed from the vehicle vertical direction. Furthermore, a concave shape portion78in which the lower side is opened as viewed from the vehicle width direction is formed at the lower end of the upper-side upstanding portion72C. Two jointing portions79are formed at both outer sides of the concave shape portion78. The interval of the concave shape portion78in the vehicle front-back direction is set so as to have a length that allows the jointed portion77to be contained. Each jointing portion79is formed in a nearly circularly cylindrical shape, as viewed from the vehicle front-back direction. In each jointing portion79, a through-hole79A that passes through the jointing portion79in the vehicle front-back direction is formed.

The displacement allowing portion80is provided above the center of the post portion70in the vehicle vertical direction. As shown inFIG. 6, the displacement allowing portion80, as an example, is configured by a lower-side hinge portion82that is provided on the lower side in the vehicle vertical direction and an upper-side hinge portion84that is provided above the lower-side hinge portion82.

As an example, the lower-side hinge portion82is configured by the two jointing portions74, the jointed portion75and a pin83. The pin83is a circularly columnar member whose axial direction is the vehicle front-back direction, and has a size that allows the insertion into the through-hole74A and the through-hole of the jointed portion75. By inserting the pin83into the through-hole74A and the through-hole of the jointed portion75, the two jointing portions74and the jointed portion75are jointed. Thereby, the connecting portion72B can pivot around the pin83relative to the lower-side upstanding portion72A.

As an example, the upper-side hinge portion84is configured by the two jointing portions79, the jointed portion77and a pin85. The pin85is a circularly columnar member whose axial direction is the vehicle width direction, and has a size that allows the insertion into the through-hole79A and the through-hole of the jointed portion77. By inserting the pin85into the through-hole79A and the through-hole of the jointed portion77, the two jointing portions79and the jointed portion77are jointed. Thereby, the upper-side upstanding portion72C can pivot around the pin85relative to the connecting portion72B.

FIG. 7Bshows a post portion200according to a comparative example. The post portion200is extended in the vehicle vertical direction. The post portion200includes an upstanding portion202, a lower flange204that projects from the lower end of the upstanding portion202in the vehicle width direction, and an upper flange206that projects from the upper end of the upstanding portion202in the vehicle width direction. The lower flange204is welded to the bottom wall22. The upper flange206is welded to the upper wall24.

In the post portion200according to the comparative example, in the case where a load F from the upper wall24of the tank body20is applied due to the collision of the vehicle or the like and the upper wall24is displaced relative to the bottom wall22, the post portion200restricts the disposition of the upper wall24relative to the bottom wall22. Thereby, there is a possibility that an excessive stress is concentrated on the joining part between the post portion200and the upper wall24and the joining part between the post portion200and the bottom wall22. Here, the load F from the upper wall24includes a load from a direction perpendicular to a plane of the upper wall24(the vehicle vertical direction).

Next, operations and effects of the fuel tank10according to the second embodiment will be described. For the same effects as those of the fuel tank10according to the first embodiment, the description will be omitted in some cases.

In the fuel tank10according to the second embodiment shown inFIG. 5, when the tank body20(seeFIG. 1) expands or is depressed, the post portion70resists the tensile force or the compressive force, and therefore, it is possible to suppress the deformation of the tank body20. Further, the post portion70is formed integrally with the wall portion34and is extended along the standing direction of the wall portion34, and therefore, it is possible to suppress the deformation of the tank body20in a simple structure, compared to a configuration in which the post portion70and the wall portion34are separately provided.

Further, in the fuel tank10according to the second embodiment, in the case where a load is applied to the tank body20and the upper wall24(seeFIG. 1) is displaced relative to the bottom wall22of the tank body20, the displacement allowing portion80of the post portion70allows the displacement of the upper wall24relative to the bottom wall22. Specifically, in the displacement allowing portion80shown inFIG. 6, in the case where a load in the vehicle front-back direction is applied to the upper-side upstanding portion72C, the upper-side upstanding portion72C is displaced (pivots) relative to the connecting portion72B, while the lower-side upstanding portion72A and the connecting portion72B are integrated. In the case where a load in the vehicle width direction is applied to the upper-side upstanding portion72C, the upper-side upstanding portion72C and the connecting portion72B are displaced (pivot) relative to the lower-side upstanding portion72A, while the upper-side upstanding portion72C and the connecting portion72B are integrated.

FIG. 7A, in which the displacement allowing portion80is regarded as a single hinge portion, is a schematic view showing a state where the load F from the upper wall24(from the direction perpendicular to the plane of the upper wall24) is applied to the post portion70and the upper wall24is displaced relative to the bottom wall22, as an example. As described above, in the case where the load F is applied to the tank body20and the upper wall24is displaced relative to the bottom wall22of the tank body20, the displacement allowing portion80makes the part above the displacement allowing portion80of the post portion70pivot relative to the part below the displacement allowing portion80. That is, the displacement allowing portion80allows the displacement of the upper wall24relative to the bottom wall22. Therefore, an excessive stress is prevented from being concentrated on the joining part between the post portion70and the upper wall24and the joining part between the post portion70and the bottom wall22. Thereby, it is possible to suitably maintain the durability of the joining portions between the post portions70and the tank body20.

As described above, in the displacement allowing portion80shown inFIG. 6, the lower-side hinge portion82pivots around the pin83whose axial direction is the vehicle front-back direction, and the upper-side hinge portion84pivots around the pin85whose axial direction is the vehicle width direction. Thereby, regardless of whether the upper wall24(seeFIG. 1) is displaced relative to the bottom wall22(seeFIG. 1) in the vehicle front-back direction or in the vehicle width direction, it is possible to prevent an excessive stress from being concentrated on the joining portion between the post portion70and the tank body20(seeFIG. 1).

Third Embodiment

Next, a fuel tank according to a third embodiment of the disclosure will be described. Here, for components and portions having the same functions as those of the above-described fuel tank10according to the first or second embodiment, reference characters identical to the reference characters used in the first or second embodiment are assigned, and the description will be omitted.

A fuel tank10according to the third embodiment shown inFIG. 8includes the tank body20and a sub-tank90.

As an example, the sub-tank90shown inFIG. 9is composed of a thermoplastic resin, and includes the lower wall32, the wall portion34, the opening portion36, and post portions100.

As an example, the post portions100are formed integrally with the wall portion34, at the front end portion of the right wall37and the front end portion of the left wall38. That is, as an example, two post portions100are formed. The two post portions100have the same configuration. Therefore, the description will be made for the post portion100formed integrally with the right wall37, and the description of the post portion100on the left wall38will be omitted.

The post portion100is formed in a nearly circularly cylindrical shape in which the axial direction of the central axis is along the vehicle vertical direction, as an example of the cylindrical shape. Specifically, the post portion100is configured by a lower wall portion102, a peripheral wall portion104and an upper wall portion106. The lower wall portion102is formed in a nearly circular shape, as viewed from the vehicle vertical direction, and is a disk-shaped part that is integrated with the lower wall32.

The peripheral wall portion104is a part that upstands from the outer edge of the lower wall portion102in the vehicle vertical direction, as an example of the wall of the post portion100. The peripheral wall portion104is formed in a nearly ring shape, as viewed from the vehicle vertical direction. Furthermore, a lower portion of the peripheral wall portion104is integrated with the right wall37. In addition, an inflow port108into which the fuel A (seeFIG. 8) in the sub-tank90flows is formed on the peripheral wall portion104.

As an example, the inflow port108is formed from the lower end of the peripheral wall portion104to the upper end, and is opened toward the inside of the sub-tank90(the side of the auxiliary storage portion21B). The inflow port108is formed in a rectangular shape that is lengthened in the vehicle vertical direction, as viewed from the vehicle width direction. The upper wall portion106is formed in a nearly circular shape, as viewed from the vehicle vertical direction, and closes the upper end of the peripheral wall portion104. The post portion100stores the fuel A (seeFIG. 8) that flows from the auxiliary storage portion21B through the inflow port108into the inside of the peripheral wall portion104. That is, the post portion100configures a third storage portion for the fuel A.

As shown inFIG. 8, in the post portion100, the lower wall portion102is welded (joined) to the bottom wall22, and the upper wall portion106is welded (joined) to the upper wall24. In other words, the post portion100is erected between the bottom wall22and the upper wall24along the vehicle vertical direction.

Next, operations and effects of the fuel tank10according to the third embodiment will be described.

In the fuel tank10according to the third embodiment shown inFIG. 8, when the tank body20expands or is depressed, the post portion100resists the tensile force or the compressive force, and therefore, it is possible to suppress the deformation of the tank body20. Further, the post portion100is formed integrally with the wall portion34and is extended along the standing direction of the wall portion34, and therefore, it is possible to suppress the deformation of the tank body20in a simple structure, compared to a configuration in which the post portion100and the wall portion34are separately provided.

Furthermore, in the fuel tank10according to the third embodiment, the fuel A is stored also in the interior of the post portion100, and therefore, it is possible to increase the amount of the fuel A that is stored in the sub-tank90, compared to a configuration in which the post portion100is solid.

The disclosure is not limited to the above embodiments.

FIG. 10Ashows a fragile portion110in a first modification. The fragile portion110is configured by both outside portions114A,114B in the vehicle front-back direction with respect to a through-hole112that passes through the upper-side upstanding portion42B in the vehicle width direction. A total area 2×S3of sections that are of both outside portions114A,114B and that are orthogonal to the vehicle vertical direction is smaller than an area S2of a section that is of a different part of the upper-side upstanding portion42B and that is orthogonal to the vehicle vertical direction. In the fragile portion110, when a high load is input to the tank body20(seeFIG. 1), the fragile portion110is broken. Therefore, an excessive stress is prevented from being concentrated on the joining part between the post portion40and the bottom wall22(seeFIG. 1) and the joining part between the post portion40and the upper wall24(seeFIG. 1). Thereby, it is possible to suitably maintain the durability of the joining portions between the post portion40and the tank body20.

FIG. 10Bshows a fragile portion120in a second modification. The fragile portion120is configured by a longitudinal wall portion124excluding female beads122A,122B that are depressed from one side and the other side of the upper-side upstanding portion42B in the vehicle width direction toward the center in the vehicle width direction. An area S4of a section that is of the longitudinal wall portion124and that is orthogonal to the vehicle vertical direction is smaller than the area S2of a section that is of the upper-side upstanding portion42B and that is orthogonal to the vehicle vertical direction. In the fragile portion120, when a high load is input to the tank body20(seeFIG. 1), the fragile portion120is broken. Therefore, an excessive stress is prevented from being concentrated on the joining part between the post portion40and the bottom wall22(seeFIG. 1) and the joining part between the post portion40and the upper wall24(seeFIG. 1). Thereby, it is possible to suitably maintain the durability of the joining portions between the post portion40and the tank body20.

FIG. 11shows a fragile portion130in a third modification. The fragile portion130is a part configured to exclude the four ribs76B (seeFIG. 6) in the post portion70(seeFIG. 6) according to the second embodiment and to include only the axis portion76A. By making the axis portion76A function as the fragile portion130in this way, an excessive stress is prevented from being concentrated on the joining part between the post portion and the bottom wall22(seeFIG. 1) and the joining part between the post portion and the upper wall24(seeFIG. 1). Thereby, it is possible to suitably maintain the durability of the joining portions between the post portion70and the tank body20. Here, the configuration inFIG. 11is a configuration of including both the fragile portion130and the displacement allowing portion80. The displacement allowing portion80allows the relative displacement between the bottom wall22and the upper wall24, and when a high load is input to the fuel tank10(seeFIG. 1), the axis portion76A is broken.

The tank body20is not limited to a tank body made of a resin, and may be made of a metal (for example, iron).

The number of the post portions40,70,100is not limited to two or three, and may be one, or four or more.

In the post portion100of the sub-tank90according to the third embodiment, the post portion100may be provided below the center in vehicle vertical direction, and the upstanding portion42may be provided above the center. Further, on the upstanding portion42, the fragile portion130may be formed and the displacement allowing portion80may be provided.

The displacement allowing portion80is not limited to a configuration of including both the lower-side hinge portion82and the upper-side hinge portion84, and may be configured to include only one of them.

The sub-tank30,60,90may be configured such that the bottom wall22of the tank body20serves also as the lower wall32of the sub-tank30,60,90. That is, the sub-tank30,60,90may be configured such that the wall portion34stands on the bottom wall22and the lower wall32does not exist. In other words, the “configuration in which the wall portion34stands on the bottom wall22of the tank body20” includes a configuration in which the wall portion34stands directly on the bottom wall22and a configuration in which the lower wall32is provided on the bottom wall22and the wall portion34stands on the lower wall32.

Thus, the fuel tanks according to the embodiments and modifications of the disclosure have been described. Naturally, the embodiments and the modifications may be appropriately combined to be used, and various aspects can be carried out without departing from the spirit of the disclosure.