Support structure for high-pressure gas tanks

Abstract

A support structure (1) for high-pressure gas tanks (3) which are respectively disposed on outer sides of left and right side-rails (5) in the left-right direction (D2) comprises: left and right tank frames (10); and a connection frame (20). The left and right tank frames (10) have supports (11) that are fixed to the side-rails (5) and support the high-pressure gas tanks (3). On the inner side of the high-pressure gas tanks (3) in the left-right direction (D2), the supports (11) extend downward below a chassis frame (4). The connection frame (20) connects the tank frames (10) to each other below the chassis frame (4).

Description

High-pressure gas tank support structure

[0001] This case relates to a support structure for a high-pressure gas tank mounted on a vehicle with a ladder frame structure.

[0002] Conventionally, there are vehicles that run on high-pressure gas as fuel. For example, fuel cell vehicles that run on electricity generated by a chemical reaction between high-pressure hydrogen gas and oxygen (air) are known. Such vehicles are equipped with a high-pressure gas tank that stores the high-pressure gas. Patent Document 1 discloses a structure for a fuel cell vehicle in which a fuel tank located laterally outboard of a vehicle body frame is supported by a tank frame having an L-shaped main body and a fixing portion that is fixed to the vehicle body frame.

[0003] Japanese Patent Application Laid-Open No. 2020-121656

[0004] As disclosed in Patent Document 1, in a tank frame that is fixed to the side rails (body frame) laterally inward of the high-pressure gas tank (fuel tank), a moment acts inward in the left-right direction due to the weight of the high-pressure gas tank, which may cause high stress in the portion of the tank frame that is fixed to the side rail (fixing portion).

[0005] The present invention was devised in view of the above-mentioned problems, and one of its objects is to suppress the stress acting on the tank frame that supports the high-pressure gas tank.

[0006] The present invention has been made to solve at least part of the above problems, and can be realized as the following aspects or application examples.

[0007] (1) The support structure for a high-pressure gas tank according to this application example is a support structure for a high-pressure gas tank that is disposed on the left and right outer side of left and right side rails that extend in the fore-and-aft direction of the vehicle in a chassis frame having a ladder frame structure, and has support parts that are fixed to the side rails and extend below the chassis frames on the left and right inner side of the high-pressure gas tank, and is equipped with left and right tank frames that support the high-pressure gas tank, and a connecting frame that connects the tank frames below the chassis frames.

[0008] According to this application example, since a connecting frame is provided that connects the left and right tank frames together, the connecting frame can counteract the moment acting on the left and right tank frames. In other words, the connecting frame functions as a tension rod between the left and right tank frames, thereby canceling out and suppressing the moment acting on the left and right tank frames. Therefore, it is possible to suppress stress occurring in the portions of the tank frame that are fixed to the side rails.

[0009] (2) In the support structure for a high-pressure gas tank according to this application example, the left and right tank frames may have base portions extending outward in the left-right direction from the lower ends of the support portions and on which the high-pressure gas tank is placed, and the connecting frame may connect the base portions to each other via the support portions. With this configuration, the connecting frame functions as a tension rod for the left and right base portions, thereby efficiently suppressing the moment acting on the left and right tank frames. As a result, displacement and deflection of the base portions due to the moment are suppressed, thereby stabilizing the position of the base portions. Therefore, the high-pressure gas tank can be supported more stably.

[0010] (3) In the support structure for a high-pressure gas tank according to this application example, the thickness of the connecting frame may be thinner than the thickness of the base portion. This configuration allows the connecting frame to be more easily deformed than the base portion. By intentionally designing the connecting frame to be more easily deformed than the base portion, the connecting frame can be deformed while maintaining the shape of the base portion when a lateral load is applied, for example, in a side collision. As a result, the high-pressure gas tank can be moved (rotated) below the chassis frame as the connecting frame deforms, while suppressing the impact on the high-pressure gas tank. This improves the protection performance of the high-pressure gas tank.

[0011] (4) In the support structure for a high-pressure gas tank according to this application example, the tank frame may have an upper portion extending outward in the left-right direction from an upper end of the support portion, and a connecting portion connecting the base portion and the upper portion outward in the left-right direction from the support portion, and the support portion, the base portion, the upper portion, and the connecting portion may form a box shape when viewed from the front-rear direction. This configuration increases the rigidity of the tank frame compared to a case where the tank frame does not have a box shape. Therefore, the tank frame can support the high-pressure gas tank more stably, and impact input to the high-pressure gas tank during a vehicle collision is suppressed, thereby improving the protection performance of the high-pressure gas tank.

[0012] (5) In the support structure for a high-pressure gas tank according to this application example, electrical equipment of the vehicle may be disposed between the side rails, and the connecting frame may have a weak portion provided on an upper surface facing the electrical equipment. With this configuration, the connecting frame is more likely to deform around the weak portion. Therefore, when a load is applied in the lateral direction, for example, the connecting frame is more likely to deform so as to form a downward convex shape around the weak portion. In other words, the connecting frame is more likely to deform in a direction away from the electrical equipment disposed between the side rails. This makes it easier to avoid contact of the connecting frame with the electrical equipment. Therefore, the protection performance of the electrical equipment is improved.

[0013] (6) In the support structure for a high-pressure gas tank according to this application example, the electrical device may be a battery that stores power for running the vehicle. With this configuration, contact of the connecting frame with the battery as the electrical device is more easily avoided as described above, thereby improving the protection performance of the battery. Therefore, reliability regarding vehicle running is improved.

[0014] (7) In the support structure for a high-pressure gas tank according to this application example, a cooling unit may be attached to the tank frame and positioned laterally outboard of the high-pressure gas tank. With this configuration, the weight of the cooling unit acts on the tank frame in addition to the weight of the high-pressure gas tank, increasing the moment. In contrast, with this application example, which includes a connecting frame, the moment acting on the left and right tank frames can be reduced, as described above, thereby suppressing stress generated in the portions of the tank frame that are fixed to the side rails. Furthermore, since there is no need to provide a bracket separate from the tank frame to support the cooling unit on the side rails, the number of parts can be reduced.

[0015] (8) In the support structure for a high-pressure gas tank according to this application example, the connecting frame may be disposed below the center of gravity of the high-pressure gas tank. This configuration can efficiently counteract the moment acting on the tank frame due to the weight of the high-pressure gas tank. This further reduces stress generated in the portion of the tank frame that is fixed to the side rail. As a result, the strength and rigidity required of the connecting frame can be reduced, thereby reducing the cost of the connecting frame.

[0016] (9) In the support structure for a high-pressure gas tank according to this application example, a sensor for detecting gas leakage from the high-pressure gas tank may be attached to the tank frame. This configuration eliminates the need to provide a bracket for attaching the sensor separately from the tank frame, thereby reducing the number of parts. Furthermore, by attaching the sensor related to the high-pressure gas tank to the tank frame that supports the high-pressure gas tank, the sensor can be easily located near the high-pressure gas tank. That is, by attaching both the high-pressure gas tank and the sensor to the same tank frame, relative displacement between the high-pressure gas tank and the sensor can be easily suppressed. As a result, for example, even during a vehicle collision, the relative position of the sensor to the high-pressure gas tank is more easily maintained (the high-pressure gas tank and the sensor are more likely to be displaced together). Therefore, the sensor can be more reliably activated.

[0017] According to the present invention, it is possible to suppress the stress acting on the tank frame that supports the high-pressure gas tank.

[0018] Fig. 1 is a top view schematically showing a vehicle undercarriage to which a support structure for a high-pressure gas tank according to one embodiment is applied. Fig. 2 is a front view schematically showing the undercarriage of Fig. 1. Fig. 3 is a front view (similar to Fig. 2) illustrating the operation of the support structure of Fig. 1. Fig. 4 is a front view (similar to Fig. 2) illustrating one deformation mode of the support structure of Fig. 1. Fig. 5 is a front view (corresponding to the partially enlarged view of Fig. 2) showing one modified example of a connecting frame provided in the support structure of Fig. 1. Fig. 6 is a front view (corresponding to Fig. 2) showing another modified example of a connecting frame provided in the support structure of Fig. 1.

[0019] The following describes embodiments (aspects, application examples) of the present invention with reference to the drawings. The following embodiments are merely examples, and are not intended to exclude various modifications or applications of techniques not explicitly described in the embodiments. The configurations of the following embodiments can be modified in various ways without departing from the spirit of the invention. Furthermore, they can be selected or combined as needed.

[0020] 1, a support structure 1 for a high-pressure gas tank according to this embodiment (hereinafter also simply referred to as the "support structure 1") is a structure for supporting a high-pressure gas tank 3 (hereinafter also simply referred to as the "tank 3") mounted on a vehicle 2. The vehicle 2 is, for example, a fuel cell truck (fuel cell vehicle), and is equipped with a chassis frame 4 having a ladder frame structure.

[0021] 1 shows the undercarriage of a vehicle 2, including a tank 3 and a chassis frame 4, and omits the body, cab, and other components mounted on the chassis frame 4. Hereinafter, the longitudinal direction D1, lateral direction D2, and vertical direction D3 of the vehicle 2 will also be referred to as the vehicle length direction D1, vehicle width direction D2, and vehicle height direction D3, respectively. In the drawing, the front, right, and top of the vehicle 2 are indicated by Fr, Rh, and Up, respectively.

[0022] The chassis frame 4 has left and right side rails 5 extending in the vehicle length direction D1 and multiple cross members 6 extending in the vehicle width direction D2. The left and right side rails 5 are spaced apart from each other in the vehicle width direction D2. Each side rail 5 has, for example, a channel shape formed by upper and lower flanges and a web connecting them. Each cross member 6 is disposed between the left and right side rails 5 to connect the side rails 5. However, the cross members 6 are not disposed in the mounting space for the battery 7 (described later) or in a position overlapping with the connecting frame 20 in the vehicle height direction D3. Note that FIG. 1 shows only two of the multiple cross members 6 provided on the vehicle 2.

[0023] The tank 3 is a container that stores high-pressure gas. The tank 3 installed in a fuel cell vehicle stores, for example, hydrogen gas as the high-pressure gas. The high-pressure gas in the tank 3 may be used as fuel for running the vehicle 2. Here, the tank 3 has, as an example, a cylindrical main body 31 and hemispherical end portions 32 that close both ends of the main body 31. The tank 3 is installed in an orientation in which the axis 33 of the main body 31 extends along the vehicle length direction D1. In this embodiment, the center of gravity 34 of the tank 3 is assumed to be located on the axis 33.

[0024] The tanks 3 are disposed outward in the vehicle width direction D2 from the left and right side rails 5. More specifically, the tanks 3 are disposed to the left of the left side rail 5 and to the right of the right side rail 5. In the vehicle 2 of this embodiment, the left and right tanks 3 are disposed adjacent to each of the left and right side rails 5. Each tank 3 is located, for example, between the front wheels and rear wheels (not shown) of the vehicle 2.

[0025] The left and right tanks 3 are formed identically and are arranged symmetrically. That is, the left and right tanks 3 have the same weight and are also arranged equally relative to the adjacent side rails 5. As shown in Figure 2, in this embodiment, the lower end of each tank 3 is located below the chassis frame 4 (side rails 5 and cross members 6).

[0026] Various devices of the vehicle 2 are arranged between the side rails 5. In the vehicle 2 of this embodiment, a battery 7 that stores power for running the vehicle 2 is mounted in the space between the side rails 5 in an area that overlaps with the left and right tanks 3 when viewed from the vehicle width direction D2. The battery 7 is mounted at approximately the same height as the left and right tanks 3. The battery 7 is an example of an electrical device of the vehicle 2. For example, the battery 7 may store power generated by a chemical reaction between hydrogen gas as a high-pressure gas supplied from the tanks 3 and oxygen (air). The battery 7 is supported by each of the left and right side rails 5 via brackets (not shown).

[0027] Cooling units 8 that cool devices mounted on the vehicle 2 are disposed outward of the left and right tanks 3 in the vehicle width direction D2. More specifically, the cooling units 8 are disposed to the left of the left tank 3 and to the right of the right tank 3. Each cooling unit 8 includes, for example, a radiator and a fan. Each cooling unit 8 may further include a pedestrian guard disposed outward of the radiator and the fan in the vehicle width direction D2.

[0028] [1-2. Support Structure] The support structure 1 includes left and right tank frames 10 that respectively support the left and right tanks 3, and a connecting frame 20 that connects the left and right tank frames 10 together below the chassis frame 4. Each tank frame 10 serves as a bracket for supporting the tank 3 on the side rails 5. Meanwhile, the connecting frame 20 serves as a support beam for resisting the moment acting on the tank frames 10 due to the weight of the tank 3. Note that the support structure 1 of this embodiment is provided independently of brackets (not shown) that support the battery 7 on the side rails 5.

[0029] <Tank Frame> The left and right tank frames 10 are configured approximately the same. Unless otherwise specified, the following description will focus on one of the left and right tank frames 10. That is, in the following description of the tank frame 10, the elements of the tank frame 10 (support portion 11, base portion 12, upper portion 13, etc.), the side rails 5, the tank 3, and other devices refer to the side on which the tank frame 10 in question is located, unless otherwise specified.

[0030] The tank frame 10 has a support portion 11 that extends in the vehicle height direction D3 and is fixed to the side rail 5. The support portion 11 extends further inward in the vehicle width direction D2 (toward the side rail 5) than the tank 3 and further downward than the chassis frame 4. The upper end of the support portion 11 is fastened to the outer surface (web) of the side rail 5 in the vehicle width direction D2 by, for example, a bolt and a nut.

[0031] The tank frame 10 of this embodiment further includes a base portion 12 extending outward in the vehicle width direction D2 from the lower end of the support portion 11, an upper portion 13 extending outward in the vehicle width direction D2 from the upper end of the support portion 11, and a connecting portion 14 connecting the base portion 12 and the upper portion 13 on a position outside the support portion 11 in the vehicle width direction D2. The tank frame 10 has a box shape (rectangle) when viewed from the vehicle length direction D1 with these support portions 11, base portion 12, upper portion 13, and connecting portion 14. Note that the method of connecting the support portions 11, base portion 12, upper portion 13, and connecting portion 14 to one another is not particularly limited, and may be, for example, fastening using bolts and nuts.

[0032] The base portion 12 extends in the vehicle width direction D2 below the tank 3. An inner end of the base portion 12 in the vehicle width direction D2 is connected to a lower end of the support portion 11. An outer end of the base portion 12 in the vehicle width direction D2 is connected to the cooling unit 8. The tank 3 is placed on the base portion 12. In this way, the base portion 12 supports the tank 3 from below.

[0033] The upper portion 13 extends in the vehicle width direction D2 above the tank 3. Here, an example is shown of the upper portion 13, whose inner end in the vehicle width direction D2 slopes obliquely downward toward the support portion 11 so as to fit along the cylindrical main body portion 31 of the tank 3. The inner end of the upper portion 13 in the vehicle width direction D2 is connected to the upper end of the support portion 11. The outer end of the upper portion 13 in the vehicle width direction D2 is connected to the cooling unit 8. The support portion 11, the base portion 12, and the upper portion 13 are arranged to surround the main body portion 31 of the tank 3.

[0034] 1, in this embodiment, a plurality of support portions 11, base portions 12, and upper portions 13 are arranged at intervals in the vehicle length direction D1 in an area overlapping with the tank 3 when viewed from the vehicle width direction D2. In the left and right tank frames 10, the positions (pitch) of the support portions 11, base portions 12, and upper portions 13 in the vehicle length direction D1 are equal.

[0035] The connecting portion 14 extends along the vehicle height direction D3, outside the axis 33 of the tank 3 in the vehicle width direction D2. The connecting portion 14 is formed, for example, in a substantially U-shape that protrudes forward or backward when viewed in the vehicle width direction D2, so as to fit along the hemispherical end portion 32 of the tank 3. The connecting portion 14 is disposed near the end portion 32 of the tank 3.

[0036] In this embodiment, a support structure 1 is exemplified in which the left tank frame 10 has one connecting portion 14 arranged near the rear end 32 of the tank 3, and the right tank frame 10 has two connecting portions 14 arranged near both ends 32 of the tank 3. In the left tank frame 10, one connecting portion 14 connects the rearmost base portion 12 and upper portion 13. On the other hand, in the right tank frame 10, one connecting portion 14 connects the forwardmost base portion 12 and upper portion 13, and another connecting portion 14 connects the rearmost base portion 12 and upper portion 13. However, the number and arrangement of the connecting portions 14 in the left and right tank frames 10 are not limited to those exemplified here.

[0037] The tank frame 10 of this embodiment further has upper connecting portions 15 that connect adjacent upper portions 13. The upper connecting portions 15 extend along the vehicle length direction D1 and further outward in the vehicle width direction D2 than the axis 33 of the tank 3. Here, a support structure 1 is shown as an example in which two upper connecting portions 15 are provided on each tank frame 10. The tank 3 is held on the tank frame 10 via belts, brackets, etc. (not shown).

[0038] As described above, the outer ends of the base portion 12 and the upper portion 13 in the vehicle width direction D2 are connected to the cooling unit 8, and therefore it can be said that the cooling unit 8 is attached to the tank frame 10. In this way, the tank frame 10 of this embodiment also serves as a bracket for supporting the cooling unit 8 on the side rails 5.

[0039] In addition, a sensor (not shown) that detects gas leakage from the tank 3 (hereinafter also referred to as a "leak sensor") is attached to the tank frame 10. In this way, the tank frame 10 of this embodiment also serves as a bracket for attaching the leak sensor near the tank 3 and supporting it on the side rail 5.

[0040] Furthermore, a replenishment unit 9 including a nozzle for replenishing high-pressure gas into each tank 3 from outside the vehicle 2 is also attached to either the left or right tank frame 10 (the right in this embodiment). Here, the replenishment unit 9 is illustrated as being attached to the front connecting portion 14 of the right tank frame 10 via front and rear auxiliary brackets 16. In this way, the right tank frame 10 in this embodiment also serves as a bracket for attaching the replenishment unit 9 near the tank 3 and supporting it on the side rail 5.

[0041] <Connecting Frame> The connecting frame 20 is a cross beam that extends in the vehicle width direction D2, and is disposed between the left and right tank frames 10. In the support structure 1 of this embodiment, a plurality of connecting frames 20 are disposed at intervals in the vehicle length direction D1. The positions (pitch) of the plurality of connecting frames 20 in the vehicle length direction D1 correspond to the positions (pitch) of the plurality of support portions 11 in the vehicle length direction D1, respectively. In other words, when viewed from the vehicle height direction D3, the connecting frame 20 is aligned on the same straight line (in the vehicle width direction D2) as the left and right support portions 11, the base portion 12, and the upper portion 13.

[0042] As shown in Figure 2, the connecting frame 20 of this embodiment connects the left and right base portions 12 via the left and right support portions 11. That is, the connecting frame 20 is positioned at the same position as the left and right base portions 12 in the vehicle length direction D1 and the vehicle height direction D3, and is aligned with the left and right base portions 12 on a straight line extending in the vehicle width direction D2. The connecting frame 20 is disposed below the axis 33 and center of gravity 34 of the tank 3 and the battery 7. Note that the upper surface portion 22 of the connecting frame 20 that faces the battery 7 may be disposed with a gap between it and the battery 7.

[0043] The connecting frame 20 is, for example, hollow and has a rectangular closed cross-section. The connecting frame 20 is formed so as to have lower strength and rigidity than both the cross member 6 and the base portion 12. In this embodiment, the thickness ta of the connecting frame 20 is thinner than the thickness tb of the base portion 12 (ta<tb), so that the strength and rigidity of the connecting frame 20 are lower than those of the base portion 12. Note that the thicknesses ta and tb referred to here are "thicknesses" corresponding to the dimensions in the vehicle height direction D3.

[0044] Both ends of the connecting frame 20 in the vehicle width direction D2 are attached to the lower ends of the support parts 11 via, for example, mounting brackets 21. Here, the mounting bracket 21 is shown as an example, having a substantially triangular shape made up of an L-shaped plate and a plate extending diagonally so as to connect both ends of the L-shaped plate. The mounting bracket 21 is disposed in the gap between the support parts 11 and the battery 7. The mounting bracket 21 is, for example, welded or fastened to both the upper surface 22 of the connecting frame 20 and the inner surface of the support parts 11 in the vehicle width direction D2 (the surface facing the battery 7).

[0045] <Modifications of connecting frame> The configuration of the connecting frame 20 is not limited to the above example. As illustrated in Fig. 5, the connecting frame 20 may have a weak portion 23 provided on the upper surface portion 22. The weak portion 23 is a portion of the upper surface portion 22 that is formed to have lower strength and rigidity than other portions. The weak portion 23 becomes a base point for deformation when a load L in the vehicle width direction D2 acts on the connecting frame 20. Here, an example of the weak portion 23 is shown, which is formed as a notch.

[0046] 6 , instead of the generally triangular mounting bracket 21 described above, the connecting frame 20 may be pin-connected to the support portion 11 via a support bracket 24 extending diagonally downward from the support portion 11. The support bracket 24 is a plate extending diagonally downward and inward in the vehicle width direction D2 from a position slightly above the lower end of the support portion 11. The support bracket 24 is disposed in the gap between the support portion 11 and the battery 7, and is welded or fastened to the inner surface of the support portion 11 in the vehicle width direction D2 (the surface facing the battery 7), for example.

[0047] Both end portions 27 of the connecting frame 20 in the vehicle width direction D2 are rotatably attached to the lower end portions of the support brackets 24 via pins 25. In this way, the connecting frame 20 of this modified example is not firmly fixed to the left and right tank frames 10 so that relative displacement is not possible, but is connected to them with a degree of freedom so that a certain degree of relative displacement (rotation) is allowed.

[0048] The connecting frame 20 illustrated in Figure 6 is substantially U-shaped when viewed in the vehicle length direction D1. More specifically, the connecting frame 20 of this modified example has an intermediate portion 26 in the vehicle width direction D2 that extends linearly, while both end portions 27 in the vehicle width direction D2 are curved upward. In the connecting frame 20 having this shape, the intermediate portion 26 is positioned below the battery 7, and both end portions 27 are positioned outside the battery 7 in the vehicle width direction D2, thereby avoiding interference with the battery 7. Note that in Figures 5 and 6, elements that are the same as or correspond to elements already described are designated by the same reference numerals, and redundant description will be omitted here.

[0049] 3, a moment M acting inward in the vehicle width direction D2 acts on the tank frame 10 due to the weight W of the tank 3. If the connecting frame 20 described above were not provided, the connecting frame 20 would not be able to withstand the moment M, and high stress would be generated in the portion of the tank frame 10 that is fixed to the side rail 5 (here, the upper end of the support portion 11).

[0050] In contrast, according to the support structure 1 described above, the connecting frame 20 that connects the left and right tank frames 10 is provided, so the connecting frame 20 can counteract the moment M acting on the left and right tank frames 10. In other words, the connecting frame 20 functions as a tension rod between the left and right tank frames 10, thereby canceling out and suppressing the moment M acting on the left and right tank frames 10. Therefore, stress generated in the portions of the tank frame 10 that are fixed to the side rails 5 can be suppressed.

[0051] In particular, when the weights W of the left and right tanks 3 are equal, the moment M acting on the left and right tank frames 10 due to the weights W of the tanks 3 is equal in magnitude and directed in opposite directions. In this case, the connecting frame 20 disposed between the left and right tank frames 10 can cancel out the moment M acting on the left and right tank frames 10. This makes it possible to efficiently suppress stress occurring in the portions of the tank frame 10 that are fixed to the side rails 5.

[0052] (2) The weight W of the tank 3 acts directly on the base portion 12 on which the tank 3 is placed. Therefore, if the connecting frame 20 connects the base portions 12 together via the support portion 11, the connecting frame 20 functions like a tension rod for the left and right base portions 12, thereby efficiently suppressing the moment M acting on the left and right tank frames 10. As a result, the displacement and deflection of the base portions 12 caused by the moment M is suppressed, and the position of the base portions 12 can be stabilized. Therefore, the tank 3 can be supported more stably.

[0053] (3) If the thickness ta of the connecting frame 20 is thinner than the thickness tb of the base portion 12, the connecting frame 20 can be made more deformable than the base portion 12. By intentionally designing the connecting frame 20 to be more deformable than the base portion 12, as shown in FIG. 4 , when a load L in the vehicle width direction D2 acts on the support structure 1 in a side collision, for example, the connecting frame 20 can be deformed while maintaining the shape of the base portion 12. As a result, the tank 3 can be moved (rotated) below the chassis frame 4 as the connecting frame 20 deforms, while suppressing the impact input to the tank 3 (see arrow A in FIG. 4 ). This improves the protection performance of the tank 3. Note that FIG. 4 illustrates one deformation mode of the connecting frame 20, but does not show the deformation of the chassis frame 4, and the mounting bracket 21 is omitted.

[0054] (4) As shown in Figure 2, if the tank frame 10 has a box shape with the support portion 11, base portion 12, upper portion 13, and connecting portion 14 when viewed from the vehicle length direction D1, the rigidity can be increased compared to when the tank frame 10 does not have such a box shape. Therefore, the tank 3 can be supported more stably by the tank frame 10, and the impact input to the tank 3 in the event of a collision of the vehicle 2 is suppressed, thereby improving the protection performance of the tank 3.

[0055] (5) As shown in FIG. 5 , if the connecting frame 20 has a weak portion 23 provided on the upper surface portion 22, the connecting frame 20 is more likely to deform around the weak portion 23. Therefore, for example, when a load L is applied in the vehicle width direction D2, the connecting frame 20 is more likely to deform so as to form a downward convex shape around the weak portion 23 (see the dashed dotted line in FIG. 5 ). In other words, the connecting frame 20 is more likely to deform in a direction away from the electrical equipment (battery 7 in this embodiment) arranged between the side rails 5. This makes it easier to prevent the connecting frame 20 from coming into contact with the electrical equipment. This improves the protection performance of the electrical equipment. Note that while FIGS. 4 and 5 illustrate an example of a load L applied from the left, a deformation mode symmetrical to that shown in FIGS. 4 and 5 is obtained for a load L applied from the right.

[0056] (6) If the electrical device disposed between the side rails 5 is a battery 7 that stores power for running the vehicle 2, contact of the connecting frame 20 with the battery 7 as electrical device can be easily avoided as described above, thereby improving the protection performance of the battery 7. Therefore, reliability regarding the running of the vehicle 2 can be improved.

[0057] (7) As shown in Figure 3, in a tank frame 10 to which a cooling unit 8 is attached that is positioned outboard of the tank 3 in the vehicle width direction D2, the weight W' of the cooling unit 8 acts in addition to the weight W of the tank 3, increasing the moment M. In this case, there is a risk that even higher stress will be generated in the portion of the tank frame 10 that is fixed to the side rail 5 (here, the upper end of the support portion 11).

[0058] In contrast, with the support structure 1 including the connecting frame 20, as described above, the moment M acting on the left and right tank frames 10 can be reduced, thereby suppressing stress generated in the portions of the tank frame 10 that are fixed to the side rails 5. Furthermore, if the cooling unit 8 is attached to the tank frame 10, there is no need to provide a bracket separate from the tank frame 10 to support the cooling unit 8 on the side rails 5, which reduces the number of parts.

[0059] (8) The connecting frame 20, which is positioned below the center of gravity 34 of the tank 3, can efficiently counteract the moment M acting on the tank frame 10 due to the weight W of the tank 3. This makes it easier to further suppress stress generated in the portions of the tank frame 10 that are fixed to the side rails 5. As a result, the strength and rigidity required of the connecting frame 20 are reduced, which allows for cost reduction of the connecting frame 20.

[0060] Furthermore, by arranging the connecting frame 20 as low as possible in the vehicle 2, it becomes easier to ensure space for arranging other devices (for example, the battery 7) above the connecting frame 20. This improves the layout performance of the devices in the vehicle 2.

[0061] (9) If a leak sensor that detects gas leakage from the tank 3 is attached to the tank frame 10, there is no need to provide a bracket for attaching this leak sensor separately from the tank frame 10, thereby reducing the number of parts. Also, by attaching the leak sensor related to the tank 3 to the tank frame 10 that supports the tank 3, it becomes easier to arrange the leak sensor near the tank 3. In other words, by attaching both the tank 3 and the leak sensor to the same tank frame 10, it becomes easier to suppress relative displacement between the tank 3 and the leak sensor. As a result, for example, even in the event of a collision of the vehicle 2, the relative position of the leak sensor to the tank 3 is more likely to be maintained (the tank 3 and the leak sensor are more likely to be displaced together). Therefore, the leak sensor can be operated more reliably.

[0062] (10) If the supply unit 9 for supplying high-pressure gas into the tank 3 is attached to the tank frame 10, it is not necessary to separately extend a bracket for attaching the supply unit 9 from the side rail 5, thereby reducing the number of parts. In this way, if the above-mentioned sensors, supply unit 9, and other devices related to the tank 3 are attached together to the tank frame 10, the number of parts can be reduced and the layout performance around the tank 3 can be improved.

[0063] (11) As shown in Figure 6, if both end portions 27 of the connecting frame 20 in the vehicle width direction D2 are attached to the left and right tank frames 10 so as to be rotatable, relative displacement (relative vibration and twisting between the left and right) of the left and right tank frames 10 and side rails 5 can be more easily tolerated. Therefore, even if the left and right tank frames 10 and side rails 5 move differently from each other during travel, for example, stress concentration can be suppressed by the connecting frame 20 rotating relative to the left and right tank frames 10. As a result, the strength and rigidity required of the support structure 1 and the chassis frame 4 can be reduced, thereby reducing the cost of the vehicle 2.

[0064] (12) As shown in Figure 6, if both end portions 27 of the connecting frame 20 in the vehicle width direction D2 are curved upward from the intermediate portion 26, the both end portions 27 can be connected to the tank frame 10 above the intermediate portion 26. This ensures space for arranging other devices (for example, the battery 7) above the connecting frame 20, while also allowing the both end portions 27 of the connecting frame 20 in the vehicle width direction D2 to be connected to the tank frame 10 by utilizing the gap between this device and the support portion 11. This improves space efficiency.

[0065] (13) If the support structure 1 is provided independently of the bracket that supports the battery 7 on the side rail 5, the battery 7 can be attached and detached independently of the support structure 1. This prevents the work of attaching and detaching the battery 7 from becoming complicated.

[0066] [3. Other] The above-described configuration of the support structure 1 is one example. The arrangement and number of the tank frames 10 and connecting frames 20 in the support structure 1 may be changed as appropriate depending on, for example, the shape, arrangement, and number of the tanks 3. The support structure 1 may include left and right (at least two) tank frames 10 and at least one connecting frame 20 that connects these tank frames 10 together.

[0067] The tank frame 10 only needs to have at least the support portion 11, and the base portion 12, upper portion 13, connecting portion 14, etc. may be omitted. The tank frame 10 may also be formed as a dedicated bracket for the tank 3. That is, the cooling unit 8, replenishing unit 9, and leak sensor may be attached to the side rails 5 by a bracket separate from the tank frame 10.

[0068] The connecting frame 20 may be connected directly to the tank frame 10 without using the mounting bracket 21 or the support bracket 24. Furthermore, the connecting frame 20 may be connected to a portion of the support portion 11 other than the lower end portion, or the tank frames 10 may be connected to each other by being directly connected to the left and right base portions 12 without using the left and right support portions 11.

[0069] The above-described relationship between the strength and rigidity of the connecting frame 20 and the base portion 12 and the cross member 6 is one example. Furthermore, instead of the above-described relationship between the thicknesses ta and tb (ta<tb), for example, by appropriately selecting the materials of the connecting frame 20 and the base portion 12, the strength and rigidity of the connecting frame 20 may be made lower than those of the base portion 12. The same applies to the cross member 6; for example, by adjusting the thickness of the members or selecting the materials, the strength and rigidity of the connecting frame 20 may be made lower than those of the cross member 6.

[0070] The weak portions 23 of the connecting frame 20 are not limited to the notches described above, and may have any structure as long as they are more easily deformed than other portions of the upper surface portion 22. The connecting frame 20 may also have a plurality of weak portions 23 provided on the upper surface portion 22 at intervals in the vehicle width direction D2. Note that various devices such as an on-board charger, a DC / DC converter, an electronic control device, a compressor, and an electric pump may be disposed in the space above the connecting frame 20 instead of or in addition to the battery 7 described above.

[0071] The shape, arrangement, and number of the tanks 3 described above are merely examples. At least one tank 3 may be provided on each side of the left and right side rails 5 in the vehicle width direction D2. The high-pressure gas stored in the tanks 3 is not limited to hydrogen gas. Furthermore, the vehicle 2 to which the support structure 1 described above is applied is not limited to a fuel cell vehicle.

[0072] [4. Supplementary Notes] Supplementary notes regarding the above embodiments are disclosed below.

[0073] (Note 1) A support structure for a high-pressure gas tank that is arranged on the left and right outer sides of left and right side rails that extend in the fore-and-aft direction of a vehicle in a chassis frame having a ladder frame structure, the support structure for a high-pressure gas tank comprising: left and right tank frames that are fixed to the side rails and have support parts that extend below the chassis frames and are laterally inward of the high-pressure gas tank, and support the high-pressure gas tank; and a connecting frame that connects the tank frames below the chassis frames.

[0074] (Supplementary Note 2) The support structure for a high-pressure gas tank according to Supplementary Note 1, characterized in that the left and right tank frames extend outward in the left-right direction from the lower ends of the support parts and have base parts on which the high-pressure gas tank is placed, and the connecting frame connects the base parts to each other via the support parts.

[0075] (Supplementary Note 3) The support structure for a high-pressure gas tank according to Supplementary Note 2, wherein the thickness of the connecting frame is thinner than the thickness of the base portion.

[0076] (Supplementary Note 4) The support structure for a high-pressure gas tank according to Supplementary Note 2 or 3, characterized in that the tank frame has an upper portion extending outward in the left-right direction from an upper end of the support portion, and a connecting portion connecting the base portion and the upper portion outward in the left-right direction from the support portion, and the support portion, the base portion, the upper portion, and the connecting portion form a box shape when viewed from the front-to-rear direction.

[0077] (Appendix 5) The support structure for a high-pressure gas tank according to any one of Appendices 1 to 4, characterized in that electrical equipment of the vehicle is arranged between the side rails, and the connecting frame has a weak part provided on an upper surface portion facing the electrical equipment.

[0078] (Supplementary Note 6) The support structure for a high-pressure gas tank according to Supplementary Note 5, wherein the electrical device is a battery that stores power for running the vehicle.

[0079] (Appendix 7) The support structure for a high-pressure gas tank according to any one of Appendices 1 to 6, characterized in that a cooling unit is attached to the tank frame and is positioned outward in the left-right direction from the high-pressure gas tank.

[0080] (Supplementary Note 8) The support structure for a high-pressure gas tank according to any one of Supplementary Notes 1 to 7, wherein the connecting frame is disposed below the center of gravity of the high-pressure gas tank.

[0081] (Appendix 9) The support structure for a high-pressure gas tank according to any one of appendices 1 to 8, characterized in that a sensor for detecting gas leakage from the high-pressure gas tank is attached to the tank frame.

[0082] REFERENCE SIGNS LIST 1 Support structure 2 Vehicle 3 Tank (high-pressure gas tank) 4 Chassis frame 5 Side rail 6 Cross member 7 Battery 8 Cooling unit 9 Replenishment unit 10 Tank frame 11 Support portion 12 Base portion 13 Upper portion 14 Connecting portion 15 Upper connecting portion 16 Auxiliary bracket 20 Connecting frame 21 Mounting bracket 22 Top surface portion 23 Weak portion 24 Support bracket 25 Pin 26 Middle portion 27 Both ends 31 Main body portion 32 End portion 33 Axis 34 Center of gravity A Arrow D1 Vehicle length direction (front-to-rear direction) D2 Vehicle width direction (left-to-right direction) D3 Vehicle height direction (up-down direction) L Load M Moment ta Wall thickness tb Wall thickness W, W' Weight

Claims

1. A support structure for a high-pressure gas tank that is located on the left and right outer sides of left and right side rails that extend in the fore-and-aft direction of a vehicle in a chassis frame having a ladder frame structure, characterized in that it comprises: left and right tank frames that are fixed to the side rails and have support parts that extend below the chassis frames and are laterally inward of the high-pressure gas tank, and support the high-pressure gas tank; and a connecting frame that connects the tank frames below the chassis frames.

2. The support structure for a high-pressure gas tank according to claim 1, wherein the left and right tank frames have base portions that extend outward in the left-right direction from the lower ends of the support portions and on which the high-pressure gas tank is placed, and the connecting frame connects the base portions together via the support portions.

3. The support structure for a high-pressure gas tank according to claim 2, characterized in that the thickness of the connecting frame is thinner than the thickness of the base portion.

4. The support structure for a high-pressure gas tank described in claim 2, characterized in that the tank frame has an upper portion extending outward in the left-right direction from the upper end of the support portion, and a connecting portion connecting the base portion and the upper portion outside the left-right direction of the support portion, and the support portion, the base portion, the upper portion, and the connecting portion form a box shape when viewed from the front-to-rear direction.

5. The support structure for a high-pressure gas tank according to claim 1, characterized in that electrical equipment of the vehicle is arranged between the side rails, and the connecting frame has a weak part provided on the upper surface facing the electrical equipment.

6. The support structure for a high-pressure gas tank according to claim 5, wherein the electrical equipment is a battery that stores power for running the vehicle.

7. A support structure for a high-pressure gas tank according to claim 1, characterized in that a cooling unit is attached to the tank frame and positioned outside the high-pressure gas tank in the left-right direction.

8. The support structure for a high-pressure gas tank according to claim 1, characterized in that the connecting frame is positioned below the center of gravity of the high-pressure gas tank.

9. The support structure for a high-pressure gas tank according to claim 1, characterized in that a sensor for detecting gas leakage from the high-pressure gas tank is attached to the tank frame.

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