Vehicle underbody

Abstract

Vehicle underbody structure comprising: a floor panel (16) formed on a lower section of a passenger compartment (19); a round, cylindrical high-pressure tank (18) arranged under the floor panel (16) and supported by a vehicle frame element (17); a box-shaped housing (22) in which a high-pressure tank (18) is received and which includes a bottom wall (44) formed by at least a part of a support panel (45), as well as a circumferential wall (46) projecting upwards from the bottom wall (44) in such a way as to surround the bottom wall (44), and a cover element (42) arranged on the side of the circumferential wall (46) opposite the bottom wall (44);and a force transmission element (70, 72) arranged between the base panel (16) and the high-pressure vessel (18), and which transmits a force from the base panel (16) to the high-pressure vessel (18), characterized in that the force transmission element (70, 72) comprises an upper coupling piece (72) arranged outside the housing (22) and connecting a top of the cover element (42) and the base panel (16), and a lower coupling piece (70) arranged inside the housing (22) and connecting a bottom of the cover element (42) and the high-pressure vessel (18).

Description

BACKGROUNDTechnical FieldThe present invention relates to a vehicle underbody structure.Prior ArtJP 2003-267067 A discloses a fuel tank mounting arrangement in which a fuel tank is formed by connecting a plurality of cylindrical tank bodies, and the fuel tank is mounted at an installation location in the vehicle. When a high-pressure container used as a fuel tank is installed on a vehicle, some degree of incidence is required in terms of effective binding of the high-pressure container with respect to the position of the high-pressure container and the relationship with other components. US 7 270 209 B2 discloses a vehicle lower part structure according to the preamble of claim 1.SUMMARYFor example, no consideration is given to the relationship with a floor panel when a high-pressure tank is disposed in a vehicle underbody. It is conceivable that the floor panel may be deformed when a large force acts on the floor panel from above. Therefore, it is an object of the present invention to provide a vehicle underbody structure in which the force receiving performance of the floor panel can be improved.A vehicle underbody structure according to a first aspect includes a floor panel, a high-pressure container, and a force transmission member. The floor panel is formed at a lower portion of a passenger compartment. The high pressure reservoir is round and cylindrical in shape, and is disposed below the floor panel and supported by a vehicle frame member. A box-shaped housing in which a high-pressure container is accommodated includes a bottom wall formed by at least a part of the support panel, a peripheral wall that protrudes upward from the bottom wall so as to surround the bottom wall, and a cover member disposed on the opposite side of the peripheral wall to the bottom wall. The force transmission member is disposed between the floor panel and the high-pressure container, and transmits a force from the floor panel to the high-pressure container. The power transmission member includes an upper coupling piece disposed outside the housing and connecting an upper surface of the cover member and the floor panel to each other, and a lower coupling piece disposed inside the housing and connecting a lower surface of the cover member and the high-pressure container to each other.The vehicle lower structure according to the first aspect includes the round cylinder-shaped high-pressure container disposed below the floor panel. The high pressure reservoir is supported by the vehicle frame member. The force transmission member is disposed between the floor panel and the high-pressure container. The force transmission member transmits a force from the bottom panel to the high-pressure container. Thus, when a force acts on the floor panel from above, the force is transmitted to the high-pressure container through the force transmission member. Since the high-pressure container is supported by the vehicle frame element, the force absorbed by the high-pressure container is transmitted to the vehicle frame element. This can improve the force receiving performance as compared with cases where the force is received only by the floor panel. Further, the high-pressure container is accommodated in the box-shaped housing. This can prevent foreign matter and the like from entering the housing, whereby the high-pressure container can be protected.In a vehicle lower structure according to a second aspect, the force transmission member is made of an elastic body having elastic properties.In the vehicle lower part structure according to the second aspect, since the force transmission member is made of an elastic body, the force can be transmitted from the floor panel to the high-pressure container while the force is absorbed by the elastic body.A vehicle lower structure according to a third aspect is arranged to cover a lower surface of the high-pressure container and store the high-pressure container. In addition, the vehicle frame member is composed of a pair of rocker members disposed on each outer side in the vehicle width direction and extending along a vehicle front-rear direction. The support panel is connected to the rocker members at both edge portions of the support panel in the vehicle width direction and is disposed between the two rocker members.In the vehicle lower part structure according to the third aspect, a lower surface of the high-pressure container is covered by the support panel. This makes it possible to protect the high-pressure container from an impact from under the vehicle or from impacts from foreign bodies.In a vehicle lower part structure according to a fourth aspect, a plurality of high-pressure tanks are arranged along the floor panel such that a cylinder axial direction of each high-pressure tank is in the same direction.In the vehicle lower structure according to the fourth aspect, a plurality of high-pressure tanks are arranged to extend in the same direction, thereby enabling a denser arrangement, so that a larger number of high-pressure tanks can be arranged under the floor panel.In a vehicle lower structure according to a fifth aspect, the high-pressure container is disposed such that the longitudinal direction thereof is in the vehicle front-rear direction.In the vehicle lower structure according to the fifth aspect, the longitudinal direction of the high-pressure container extends in the vehicle front-rear direction. Thereby, the length of a single high-pressure container can be increased as compared with cases where the high-pressure containers are arranged such that the longitudinal direction thereof is in the vehicle width direction. Thus, a higher capacity can be achieved with fewer high-pressure containers if high-pressure containers with the same diameter are arranged.As described above, with the vehicle lower structure according to the first aspect, the force receiving performance of the floor panel can be improved using the high-pressure container.The vehicle lower part structure according to the second aspect can absorb the force from the floor panel using the elastic body.The vehicle lower structure according to the third and fourth aspects can protect the high-pressure container.The vehicle lower structure according to the fifth and sixth aspects can improve space utilization efficiency under the floor panel.BRIEF DESCRIPTION OF THE DRAWINGSExemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which: FIG. 1 is a schematic side view of a fuel cell vehicle to which a vehicle underbody structure according to a first exemplary embodiment is applied; FIG. 2 is an exploded perspective view of a high-pressure container unit according to the first exemplary embodiment; FIG. 3 is a partial sectional view showing a vehicle lower part structure according to the first exemplary embodiment in a state in section along the vehicle width direction; FIG. 4 is a partial sectional view showing a vehicle lower part structure according to the first exemplary embodiment in a state in section along the vehicle front-rear direction; FIG. 5 is an exploded perspective view of a high-pressure container unit according to a modification of the first exemplary embodiment; FIG. 6 is an exploded perspective view of a high-pressure container unit according to a second first exemplary embodiment; and FIG. 7 is a partial sectional view showing a vehicle lower part structure according to the second exemplary embodiment in a state in section along the vehicle width direction.DETAILED DESCRIPTIONFirst Exemplary EmbodimentHereinafter, with reference to the drawings, a fuel cell vehicle 11 equipped with a vehicle underbody structure according to a first exemplary embodiment will be described. Note that in the drawings, the arrow FR, the arrow UP, and the arrow RH respectively show the front direction, the upper direction, and the right vehicle side of the fuel cell vehicle 11. In the following explanation, unless otherwise specified, the simple reference to front and rear, up and down, and left and right means the front and rear in the vehicle front-rear direction, the up and down in the vehicle vertical direction, and the left and right in the vehicle width direction as viewed in the traveling direction.As shown in FIG. 1, the fuel cell vehicle 11 of the present exemplary embodiment (hereinafter, also simply referred to as "vehicle 11") is configured to include a drive motor 12, a fuel cell stack (FC stack) 14, and a high-pressure tank unit 10.In the present exemplary embodiment, as an example, the drive motor 12 is installed in the vehicle rear portion. When the drive motor 12 is driven, the power output from the drive motor 12 is transmitted to the rear wheels 13 through a transmission mechanism not illustrated in the drawings.The FC stack 14 is disposed in the vehicle front portion. The FC stack 14 is a stack structure formed by stacking a plurality of individual cells each constituting a configuration unit. The FC stack 14 serves as a high voltage power source. Each individual cell constituting the FC stack 14 generates electricity by electrochemical reaction between hydrogen gas supplied from the high-pressure container unit 10, which will be described later, and compressed air supplied from an air compressor, which is not illustrated in the drawings. The vehicle 11 further includes a storage battery, which is not shown in the drawings. The storage battery is a rechargeable battery, and a nickel-hydrogen secondary battery, a lithium-hydrogen secondary battery, or the like may be used. Electric power is supplied from the storage battery to the drive motor 12 to drive the drive motor 12, and regenerative power is recovered from the drive motor 12 during deceleration and regeneration.A floor panel 16 forming a floor of a passenger compartment 19 is disposed in a lower portion of the passenger compartment 19 of the vehicle 11. A pair of rocker members 17 serving as vehicle frame members are disposed on both outer sides of the floor panel 16 in the vehicle width direction, extending along the vehicle front-rear direction. As shown in FIG. 3, each sill member 17 has a closed cross-sectional structure formed by connecting an outer portion 17A located on the vehicle width direction outer side and an inner portion 17B located on the vehicle width direction inner side. Edges 16A of the floor panel 16 on the vehicle outer side are joined to the inner portions 17B of the respective sill members 17 by welding. Front seats 15A and rear seats 15B are disposed above the floor panel 16.The high-pressure container unit 10 is disposed at the vehicle lower side of the floor panel 16. As shown in FIG. 2, the high-pressure container unit 10 is configured to include a plurality of container bodies 18, a first pipe 20, a second pipe 21, a housing 22, and an outward pipe 32.Each container body 18 is formed as an elongated substantially round cylindrical body whose axial direction extends along its longitudinal direction. The plurality of container bodies 18 are arranged side by side in the radial direction of the container bodies 18. In the present exemplary embodiment, as an example, eleven tank bodies 18 are arranged at a uniform interval along the vehicle width direction so that the axial direction thereof is in the vehicle front-rear direction.The positions of vehicle front end portions of the eleven container bodies 18 are aligned. The seven container bodies 18 closest to the center of the vehicle are all configured to have the same axial length. The vehicle front end portions of the container bodies 18 are disposed more forward than the front seats 15A. The two tank bodies 18 on the left side of the vehicle and the two tank bodies 18 on the right side of the vehicle have a shorter length than the remaining tank bodies 18 in the vehicle front-rear direction (axial direction).Thus, the rear end portions of these four tank bodies 18 are disposed more toward the vehicle front side than the rear end portions of the other tank bodies 18. The vehicle rear end portions of the container bodies 18 are disposed further toward the rear than the front end of the rear seat 15B.Of the tank bodies 18, those disposed at the both vehicle width direction edges are disposed more toward the vehicle outer side than the centers of the respective front seats 15A in the vehicle width direction. The plurality (eleven) of container bodies 18 are arranged to be horizontally packed under the bottom panel 16.As shown in FIG. 2, each of the container bodies 18 is composed of a housing body 24, caps 30, a first reinforcing layer 26, and a second reinforcing layer 28. In the present exemplary embodiment, the case body 24 is formed of, for example, an aluminum alloy.The caps 30 are disposed at both end portions in the axial direction of the case body 24. Each cap 30 has an axial direction extending in the vehicle front-rear direction, and is formed to project outward in the axial direction from the case body 24 substantially as a hemispherical dome. Both ends of the case body 24 are closed by the caps 30. Note that, in the present exemplary embodiment, the vehicle front end caps 30 are configured similarly to the vehicle rear end caps 30. A connecting piece 30A is disposed projecting outward in the axial direction from the front end portion of each cap 30. Each connector 30A includes an opening 30B. The first pipe 20 and the second pipe 21, which will be described later, are connected to the respective openings 30B.The first reinforcing layer 26 is provided on an outer circumferential surface of the case body 24. The first reinforcing layer 26 is made of a carbon fiber reinforced plastic (CFRP). Specifically, the first reinforcing layer 26 is formed using a sheet of CFRP that would be impregnated with a thermosetting resin, for example, epoxy resin. The CFRP is wound around the outer circumferential surface of the case body 24, and then heated to form the first reinforcing layer 26. Although not shown in the drawings, the fiber direction of the first reinforcing layer 26 corresponds to the circumferential direction of the case body 24.The second reinforcing layer 28 is formed on the outer circumferential surface of the first reinforcing layer 26. The second reinforcing layer 28 is made of CFRP. Specifically, CFRP fibers impregnated with a thermosetting resin such as epoxy resin are wound around the outer circumferential surface of the first reinforcing layer 26 and the caps 30, and then heated to form the second reinforcing layer 28. Although not shown in the drawings, the fiber direction of the second reinforcing layer 28 corresponds to the axial direction of the case body 24, or a direction at a predetermined angle relative to the axial direction of the case body 24.As shown in FIGS. 3 and 4, lower couplings 70 are disposed above the housing bodies 24. A plurality of lower couplings 70 are arranged along the axial direction of each container body 18. In the present exemplary embodiment, one lower coupling piece 70 is disposed near each of the front and rear caps 30, and four lower coupling pieces 70 are disposed therebetween, so that six lower coupling pieces 70 are provided per container body 18. Each lower coupling piece 70 has an arcuate lower surface on the side of the container body 18 following the outer periphery of the housing body 24 and contacting the outer periphery of the housing body 24. An upper surface of each lower coupling piece 70 has a flat profile and contacts a lower surface 42D of a cover member 42 to be described later. Each lower coupling piece 70 is connected to either one of the case body 24 and the cover member 42, and only contacts the other of the case body 24 or the cover member 42. In the present exemplary embodiment, the lower couplings 70 are connected to the housing bodies 24. The lower coupling pieces 70 may be made of an elastic material, for example, a resin such as rubber or an elastomer.The tank bodies 18 configured as described above are connected to each other in the vehicle width direction by the first pipe 20 and the second pipe 21. The first tube 20 is an elongated tube disposed to extend in the vehicle width direction (the arrangement direction of the tank bodies 18) on the vehicle front side of the tank bodies 18. The first tube 20 is provided with fixing portions 20A that are fixed to the joints 30A of the caps 30. A plurality of fixing portions 20A are provided corresponding to the positions of the container bodies 18. In the present exemplary embodiment, eleven fixing portions 20A are provided. An externally threaded portion protruding toward the container bodies 18 is formed at each fastening portion 20A. The openings 30B (joints 30A) of the caps 30 are screwed onto the male threaded portions, thereby fixing the container bodies 18 to the first tube 20. A flow path is formed in the first pipe 20, and the inside of the plurality of tank bodies 18 is communicated with each other through this flow path. In addition, a plurality of front fastening tabs 36 are formed on the first tube 20. The front attachment tabs 36 will be described in detail later.The outward pipe 32 is disposed at the vehicle width direction center portion of the first pipe 20 (a vehicle width direction center portion of the tank bodies 18). The outward pipe 32 is a pipe body protruding toward the vehicle front side from the first pipe 20, and is formed at the fixing portion 20A at the vehicle width direction center of the first pipe 20 in the present exemplary embodiment. The lead-out pipe 32 leads out through an opening 46A formed in a peripheral wall 46 of the housing 22, as will be described later. The outward pipe 32 has a valve 34 that can open and close the flow path through the first pipe 20.The second pipe is disposed on the vehicle rear side of the tank bodies 18, and the rear end portions of the tank bodies 18 in the vehicle width direction are connected to each other by the second pipe 21. The second pipe 21 includes a plurality (eleven in the present embodiment) of fixing portions 21A, similarly to the first pipe 20. The fixing portions 21A have insertion holes into which the connection pieces 30A of the caps 30 are inserted. As shown in FIG. 4, in a state where the joints 30A are inserted into the fixing portions 21A, screws 23 are screwed into the openings 30B (see FIG. 2 ) of the joints 30A from the axially outer side, thereby fixing the second tube 21 to the container body 18. A flow path is formed in the second pipe 21, and the inside of the plurality of tank bodies 18 is communicated with each other through the flow path. As further shown in FIG. 2, the second tube 21 has a plurality of rear attachment tabs 38.Note that the container bodies 18 and the first tube 20 are accommodated in the housing 22. The housing 22 is formed substantially as a rectangular box in plan view and is configured to include a housing body 40 and the cover member 42.The housing body 40 is an upwardly open box and is configured to include a bottom wall 44 and the peripheral walls 46. The bottom wall 44 is made of aluminum alloy or the like and has a substantially rectangular shape with rounded corners in plan view. Fastening holes 44 are formed spaced apart from each other around the outer periphery of the bottom wall 44, and fastening members such as bolts B 1 and nuts B 2 are used to fasten the bottom wall 44 to the sill members 17. The housing 22 is supported by the rocker members 17 by this type of attachment.The peripheral walls 46 protrude upwardly from the bottom wall 44 and are each formed by an extruded aluminum alloy component. The peripheral walls 46 form a rectangular frame in plan view. The outer profile formed by the circumferential walls 46 is formed large enough to surround the plurality of container bodies 18. In the present exemplary embodiment, the outer profile of the peripheral walls 46 is formed large enough to accommodate eleven container bodies 18.The peripheral walls 46 are configured to include a front wall 48 extending on the vehicle front side in the vehicle width direction, a rear wall 50 extending on the vehicle rear side in the vehicle width direction, and a right wall 52 and a left wall 53 connecting the both end portions of the front wall 48 and the both end portions of the rear wall 50 along the vehicle front-rear direction. The front wall 48, the rear wall 50, the right wall 52, and the left wall 53 are each formed in a closed cross-sectional structure. Hereinafter, this will be described in detail.As shown in FIG. 4, the cross-sectional profile of the front wall 48 is formed as a closed cross-sectional profile as viewed in the vehicle width direction. Specifically, the front wall 48 is composed of a pair of front and rear vertical front walls 48A that project upward from the bottom wall 48 and are spaced apart from each other in the vehicle front-rear direction, an upper front wall 48B that connects the upper ends of the vertical front walls 48A to each other from front to rear, and a front intermediate wall 48C that connects the vertical-direction central portions of the vertical front walls 48A from front to rear.As shown in FIG. 2, the opening 46A penetrating the front wall 48 in the vehicle front-rear direction is formed at the vehicle width direction center portion of the front wall 48. The outward pipe 42 formed on the first pipe 20 leads out of the housing 24 through the opening 46A. The outward pipe 32 has the valve 34 that can open and close the flow path of the first pipe 20. This allows the amount of fluid flowing in the flow path to be controlled. One end of a pipe, which is not shown in the drawings, is connected to the valve 34, and the other end of this pipe is connected to the fuel cell stack or the like.As shown in FIG. 4, the cross-sectional profile of the rear wall 50, similar to the front wall 48, is formed as a closed cross-sectional profile as viewed in the vehicle width direction. Namely, the rear wall 50 is configured to include a pair of front and rear vertical rear walls 50A that project upward from the bottom wall 44 and are spaced apart from each other in the vehicle front-rear direction, an upper rear wall 50B that connects the upper ends of the vertical rear walls 50A from front to rear, and a rear intermediate wall 50C that connects the vertical direction middle portions of the vertical rear walls 50A from front to rear.As shown in FIG. 3, the cross-sectional profiles of the right wall 52 and the left wall 53 similar to the front wall 48 and the rear wall 50 are formed as closed cross-sectional profiles as viewed along the vehicle front-rear direction. The right wall 52 is configured to include left and right pairs of right vertical walls 52 that protrude upward from the bottom wall 44 and are spaced apart from each other in the vehicle width direction, a right upper wall 52B that connects upper ends of the right vertical walls 52A in the vehicle width direction, and a right middle wall 52C that connects vertical-direction middle portions of the right vertical walls 52A in the vehicle width direction. The left wall 53 is configured to include left and right pairs of left vertical walls 53 that protrude upward from the bottom wall 44 and are spaced apart from each other in the vehicle width direction, a left upper wall 53B that connects upper ends of the left vertical walls 53A in the vehicle width direction, and a left middle wall 53C that connects middle portions in the vertical direction of the left vertical walls 53A in the vehicle width direction. The peripheral walls 46 thus form a frame member having a closed cross-sectional structure.As shown in FIG. 2, notches 51 recessed toward the vehicle front side in plan view are formed at rear end portions of the peripheral walls 46 on both sides in the vehicle width direction (FIG. 2 shows only one of the recesses 51 on the vehicle left side). The length of the inner region of the housing 22 in the vehicle front-rear direction is thus shorter at the vehicle width direction ends than at the vehicle width direction center. As described above, therefore, the tank bodies 18 accommodated on each side in the vehicle width direction are tanks having a shorter length in the vehicle front-rear direction (axial direction) than the other tank bodies 18.As shown in FIG. 2, the cover member 42 is formed in the shape of a flat plate of aluminum alloy or the like and has a profile corresponding to that of the circumferential walls 46. Thus, both ends of a rear end portion of the cover member 42 in the vehicle width direction are formed, corresponding to the circumferential walls 46A, with notches 42A recessed toward the vehicle front side in plan view. Moreover, as shown in FIGS. 3 and 4, a step 42B is formed extending along the outer circumferential edge portion of the cover member 42. A portion of the cover member 42 that is located further on the outer circumferential side than the step 42B overlaps the upper surfaces of the circumferential walls 46 and is fastened thereto using fastening means such as bolts B 3. In this way, the upper opening of the case body 40 is closed by the cover member 42. In this locked state, the lower side 42D of the cover member 42 abuts against the lower couplings 70. Gaps are formed between the cover member 42 and the container bodies 18 at the locations other than the locations where the lower couplings 70 are disposed.Upper couplings 72 are disposed between the cover member 42 and the floor panel 16. The upper couplings 72 are disposed at positions corresponding to the lower couplings 70, that is, at positions overlying the lower couplings 70 in plan view. Each upper coupling piece 72 is connected to one of the floor panel 16 and the cover member 42 and only contacts the other of the floor panel 16 and the cover member 42. In the present exemplary embodiment, the upper couplings 72 are connected to the cover member 42. The upper couplings 72 may be made of an elastic material, for example, a resin such as rubber or an elastomer.A power transmission member of the present invention is formed of the upper couplings 72 and the lower couplings 70. Force from the bottom panel 16 is transmitted to the container bodies 18 through the upper couplings 72 and the lower couplings 70.As shown in FIGS. 2 and 4, first mounting brackets 60 are formed on the vehicle front side of the bottom wall 44.A plurality of first fastening brackets 60 are provided spaced apart from each other in the vehicle width direction, and three first fastening brackets 60 are provided in the present exemplary embodiment. The first fixing brackets 60 are formed between mutually adjacent container bodies 18.As shown in FIG. 4, the first mounting brackets 60 are brackets connected to the bottom wall 44 and the front wall 48 (the peripheral walls 46) to support the first tube 20. Each first mounting bracket 60 is configured to include a bearing portion 60A, legs 60B, and a forwardly extending portion 60C.The support portion 60A is a flat plate-like location formed to be substantially rectangular in plan view, and is disposed at a location spaced from the bottom wall 44 toward the vehicle upper side. Three of the legs 60B extend from a rear end portion and both end portions of the support portion 60A in the vehicle width direction to the bottom wall 44 (only one leg 60B extending to the vehicle rear side and one leg 60B extending to the vehicle right side are shown in FIG. 4 ). Each of the legs 60B extends obliquely downward from the support portion 60A toward the bottom wall 44, and a lower end portion of each leg 60B is bent so as to follow the bottom wall 44 and connected to the bottom wall 44.The forward extending portion 60C extends obliquely upward from a front end portion of the support portion 60A toward the peripheral wall 46. a front end portion of the forward extending portion 60C is bent upward to follow the peripheral wall 46, and is connected to the front wall 48 (peripheral wall 46).The first tube 20 has the front attachment tabs 36. A lower end portion of each front fixing tab 36 is formed with a flange 36A bent toward the vehicle rear. Each flange 36A overlaps the bearing portion 60A of the first fixing bracket 60 and is fixed thereto using a bolt 100 and a nut 102.Second mounting brackets 62 are formed on the vehicle rear side of the bottom wall 44. A plurality of second fastening brackets 62 are provided spaced apart from each other in the vehicle width direction, and three second fastening brackets 62 are provided in the present exemplary embodiment (only two of the second fastening brackets 62 are shown in FIG. 2 ). The second fixing brackets 62 are disposed at positions in the vehicle width direction corresponding to the first fixing brackets 60 (between adjacent tank bodies 18).The second fixing brackets 62 are brackets connected to the bottom wall 44 and support the second pipe 21. Each second mounting bracket 62 is configured to include a bearing portion 62A and legs 62B.The support portion 62A is a flat plate-like location formed to be substantially rectangular in plan view, and is disposed at a location spaced from the bottom wall 44 toward the vehicle upper side. A first attachment hole 62C is formed penetratingly in a central portion of the support portion 62A in the thickness direction of the support portion 62A.Four legs 62B extend from front, right, left and rear edges of the support portion 60A downward toward the bottom wall 44. each leg 62B extends obliquely downward from the support portion 62A toward the bottom wall 44, and a lower end portion of each leg 62B is bent so as to follow the bottom wall 44 and is connected to the bottom wall 44.The rear fixing tabs 38 extend downward between adjacent fixing portions 21A of the second tube 21. A lower end portion of each rear fixing bracket 38 has a flange 38A bent toward the vehicle front side. The flanges 38A extend between adjacent tank bodies 18 in the vehicle front-rear direction.A second attachment aperture 38B is formed through each flange 38A. A bolt 104 is inserted through the first fastening hole 62C formed in the bearing portion 62A of each second fastening bracket 62 and the second fastening hole 38B in the flange 38A. The bolt 104 is screwed into a nut 106 at a lower side of the bearing portion 62A, thereby fastening the two components (the bearing portion 62A and the flange 38A) to each other.The container bodies 18 are supported above the bottom wall 47 by the front fixing tabs 36 and the first fixing brackets 60, and are supported above the bottom wall 44 by the rear fixing tabs 38 and the second fixing brackets 62, in a state where the container bodies 18 are spaced apart from the bottom wall 44.The function and advantageous effects of the present exemplary embodiment will be described below.As shown in FIG. 2, the present exemplary embodiment includes a plurality of round cylindrically shaped tank bodies 18 as an array of high pressure tanks storing hydrogen fuel. This provides a degree of freedom in, for example, height and width when the container bodies 18 are placed under the bottom panel 16, which is increased as compared with cases where hydrogen is stored in a single high-pressure container having a large capacity.An axial direction end portion of each container body 18 is connected to the first pipe 20. The other end portion in the axial direction of each container body 18 is connected to the second tube 21. The internal spaces of the tank bodies 18 are thereby connected to each other via the tubes 20, 21. As a result, the plurality of container bodies 18 can form a unit that functions as a single high-pressure container, whereby the required capacity can be easily secured.In addition, in the present exemplary embodiment, when a force is applied from above to the floor panel 16, for example, when an occupant gets in or off or cargo is loaded, a part of the force is received by the rocker members 17 through the edges 16A of the floor panel 16 on the vehicle exterior side. The rest of the force applied from above to the floor panel 16 is received by the container bodies 18 via the upper couplings 72, the cover member 42 and the lower couplings 70. Further, the force is transmitted to the bottom wall 44 via the first tube 20, the front attachment tabs 36, and the first attachment brackets 60, and similarly, the force is transmitted to the bottom wall 44 via the second tube 21, the rear attachment tabs 38, and the second attachment brackets 62. The force transmitted to the bottom wall 44 is then transmitted to the sill members 17.In this way, in the present exemplary embodiment, the force acting from above on the floor panel 16 is also transmitted to the rocker members 17 through the container bodies 18, instead of being transmitted to the rocker members 17 only through the edges 16A of the floor panel 16 on the vehicle exterior side. Thus, the force can be received by the container bodies 18 instead of only the bottom panel 16, whereby the force receiving performance can be improved.Further, in the present exemplary embodiment, the upper coupling pieces 72 and the lower coupling pieces 70 are formed of elastic bodies. Thereby, the applied force can be absorbed by the elastic deformation of the upper coupling pieces 72 and lower coupling pieces 70. In addition, the upper coupling pieces 72 and the lower coupling pieces 70 are mutually superposed on each other in plan view. The force is therefore transmitted uniformly through the elastic bodies.Further, in the present exemplary embodiment, the container bodies 18 are accommodated in the box-shaped housing 22. Thus, foreign matters and the like cannot enter the housing 22, whereby the container bodies 18 can be protected.Further, in the present exemplary embodiment, the plurality of container bodies 18 are arranged side by side such that the cylinder axial direction of each container body 18 corresponding to the longitudinal direction is in the same direction. Thereby, more container bodies 18 can be disposed under the bottom panel 16 in a space efficient manner.Moreover, in the present exemplary embodiment, the plurality of tank bodies 18 are arranged such that the cylinder axial direction of each tank body 18 corresponding to the longitudinal direction is in the vehicle front-rear direction. Thereby, the length of a single container body 18 can be made longer than in cases where the container bodies 18 are arranged such that the longitudinal direction thereof is in the vehicle width direction. Thus, a larger capacity can be ensured with fewer container bodies 18 when container bodies 18 having the same diameter are arranged.Note that in the present exemplary embodiment, the lower couplings 70 are formed on each container body 18. However, it is also possible that the lower couplings 70 are provided only on some of the container bodies 18. For example, as shown in FIG. 5, the lower couplings 70 may be formed on each second tank body 18 in the vehicle width direction, with the upper couplings 72 being formed at positions corresponding to the lower couplings 70.Moreover, the upper couplings 72 do not necessarily have to be disposed at the positions corresponding to the lower couplings 70. The upper couplings 72 may be disposed at positions not overlapping the lower couplings 70 in plan view.Second Exemplary EmbodimentHereinafter, a second exemplary embodiment of a vehicle underbody structure of the present invention will be described with reference to FIGS. 6 and 7. Note that elements similar to those of the first exemplary embodiment are denoted by the same reference numerals, and description thereof is omitted accordingly.As shown in FIG. 6, in the present exemplary embodiment, a support panel 45 is formed only by a plate-shaped member that forms the bottom wall 44 of the housing 22, and neither the peripheral walls 46 (front wall 48, rear wall 50, right wall 52, left wall 53) nor the cover member 42 are provided. Attachment holes 45A are formed spaced apart from each other along the outer peripheral portion of the support panel 45, and the support panel 45 is attached to the rocker members 17 similarly to the bottom wall 44 of the first exemplary embodiment. The support panel 45 is supported by the sill members 17 due to this type of attachment.The lower couplings 70 are disposed above the container bodies 18. The lower couplings 70 abut a lower side of the floor panel 16. In the present exemplary embodiment, the force is transmitted from the bottom panel 16 to the container bodies 18 through the lower couplings 70.The function and advantageous effects of the present exemplary embodiment will be described below.In the present exemplary embodiment, similarly to the first embodiment, the degree of freedom in, for example, height and width in disposing the container bodies 18 under the floor panel 16 can be increased, and also the force receiving performance of the floor panel 16 can be improved. The lower couplings 70 are made of elastic bodies, whereby the applied force can be absorbed by the elastic deformation of the lower couplings 70.Moreover, in the present exemplary embodiment, the support panel 45 is disposed so as to cover the bottom of the container bodies 18, and the support panel 45 supports the container bodies 18.Note that, in the first and second exemplary embodiments, the container bodies 18 are supported by the rocker members 17. However, the container bodies 18 may be supported by another vehicle frame member. For example, the container bodies 18 may be supported by cross members (not shown in the drawings) extending between the sill members 17.Exemplary embodiments of the present invention have been described above. However, the present invention is not limited thereto, and can be obviously modified in various ways without departing from the spirit of the present invention.

Claims

A vehicle lower part structure comprising: a floor panel (16) formed at a lower portion of a passenger compartment (19); a round cylinder-shaped high-pressure container (18) disposed below the floor panel (16) and supported by a vehicle frame member (17); a box-shaped housing (22) accommodating a high-pressure container (18) and including a bottom wall (44) formed by at least a part of a support panel (45), and a peripheral wall (46) projecting upward from the bottom wall (44) so as to surround the bottom wall (44), and a cover member (42) disposed at the opposite side of the peripheral wall (46) to the bottom wall (44); and a power transmission member (70, 72) that is disposed between the bottom panel (16) and the high-pressure container (18) and that transmits a power from the bottom panel (16) to the high-pressure container (18), characterized in that the power transmission member (70, 72) includes an upper coupling piece (72) that is disposed outside the housing (22) and connects an upper side of the cover member (42) and the bottom panel (16) to each other, and a lower coupling piece (70) that is disposed inside the housing (22) and connects a lower side of the cover member (42) and the high-pressure container (18) to each other.The vehicle lower structure according to claim 1, wherein the force transmission member (70, 72) is made of an elastic body.The vehicle lower part structure according to claim 1 or 2, wherein: the support panel (45) is disposed so as to cover a lower side of the high-pressure container (18) and that supports the high-pressure container (18), the vehicle frame member (17) is composed of a pair of rocker members (17), and the support panel (45) is connected to the rocker members (17) at both edge portions of the support panel (45) in the vehicle width direction and is disposed between the two rocker members (17).The vehicle lower part structure according to any one of claims 1 to 3, wherein a plurality of high-pressure tanks (18) are disposed along the floor panel (16) such that a cylinder axial direction of each high-pressure tank (18) is in the same direction.The vehicle lower part structure according to any one of claims 1 to 4, wherein the high-pressure container (18) is disposed such that the longitudinal direction thereof is in the vehicle front-rear direction.

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