Vehicle undercarriage

Abstract

To provide a vehicular lower part structure which inhibits battery units from being sandwiched between a connection member and a side sill to be deformed at a side collision of a vehicle and inhibits an underfloor travel wind from entering the battery units.SOLUTION: A vehicular lower part structure includes: a side sill 1 extending in a vehicle fore-and-aft direction on an outer side in a vehicle width direction; a first battery unit 21 and a second battery unit 22 which are provided adjacent to an inner side in the vehicle width direction of the side sill 1 and spaced apart from each other in the vehicle width direction below a floor panel 8; and a connection member 60 which connects between the first battery unit 21 and the second battery unit 22. The connection member 60 includes: a vertical wall part 62 extending in the vehicle width direction and protruding to a vehicle lower side; and a slope part 64 which inclines to the vehicle lower side as it goes rearward in the rear of the vertical wall part 62. A lower end of the slope part 64 is located at the vehicle lower side relative to a lower end of the vertical wall part 62.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a vehicle underbody structure in which a battery unit is mounted under a floor. [Background technology]

[0002] Conventionally, as disclosed in Patent Document 1, a tunnel member is known that is provided to prevent underfloor wind from flowing into the interior of the floor tunnel while the vehicle is moving, thereby improving aerodynamic performance.

[0003] This tunnel member has a front wall, a rear wall and a bottom wall, and connects the lower end of the floor tunnel section in the vehicle width direction. The front wall of the tunnel member acts as a vertical wall against the underfloor traveling wind, and guides the underfloor traveling wind that attempts to enter the inside of the floor tunnel section toward the bottom of the vehicle, improving aerodynamic performance.

[0004] On the other hand, in the case of a plug-in hybrid electric vehicle (PHEV), the left and right battery units must be spaced apart on the left and right sides of the floor tunnel in the vehicle width direction due to the location of the exhaust pipe.

[0005] In this case, by providing a connecting member with a front wall extending in the vehicle width direction, similar to the tunnel member described above, at the lower part of each of the left and right battery units, it is possible to separate the underfloor traveling wind generated between the left and right battery units.

[0006] However, if a connecting member is used with a vertical dimension that allows for separation of the wind from underfloor travel, a new problem arises in that, in the event of a side collision with the vehicle, the connecting member becomes stiff and the battery unit on the side receiving the side collision load becomes pinched between the connecting member and the side sill, causing the battery unit to deform. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2016-132399 A Summary of the Invention [Problem to be solved by the invention]

[0008] Therefore, an object of the present invention is to provide a vehicle underbody structure that can prevent the battery unit from being pinched and deformed between the connecting member and the side sill during a vehicle side collision, and can also prevent underfloor wind from entering between the battery units. [Means for solving the problem]

[0009] The understructure of a vehicle according to the present invention comprises a side sill extending in the fore-and-aft direction of the vehicle on the outer side in the vehicle width direction, a first battery unit and a second battery unit arranged adjacent to the inner side in the vehicle width direction of the side sill and spaced apart in the vehicle width direction below the floor panel, and a connecting member connecting between the first battery unit and the second battery unit, the connecting member comprising a vertical wall portion extending in the vehicle width direction and protruding below the vehicle, and a slope portion rearward of the vertical wall portion and inclined downwardly towards the vehicle as it approaches the rear, and the lower end of the slope portion is configured to be located lower than the lower end of the vertical wall portion.

[0010] According to the above configuration, the lower end of the slope portion is configured to be lower than the lower end of the vertical wall portion, so that underfloor traveling wind that cannot be completely separated by the vertical wall portion can be guided downward of the vehicle by the slope portion and separated therefrom.

[0011] In addition, since the vertical wall portion is not made high, the bending deformation of the connecting member during a vehicle side collision is not hindered, and the action of the connecting member bracing itself between the battery unit on the side of the side collision load input can be suppressed, thereby preventing the battery unit from being pinched and deformed between the connecting member and the side sill.

[0012] In one embodiment of the present invention, a protruding member is provided between the first battery unit and the second battery unit, protruding upward from between the bottoms of these battery units, and the vehicle width directional outer end of the rear end of the slope portion is located at the same position as the lower end position of the side wall extending in the vertical direction of the protruding member or at a vehicle width directional outer position. The above-mentioned protruding member may be a tunnel insulator that insulates the exhaust pipe from heat.

[0013] According to the above configuration, the position of the vehicle width direction outer end of the rear end of the slope portion can prevent the detached wind from the rear end of the slope portion from entering inside the above-mentioned protruding member.

[0014] In one embodiment of the present invention, the vertical wall portion is provided at a front portion thereof with a first inclined portion that is inclined downwardly toward the rear of the vehicle. According to the above configuration, the underfloor traveling wind is guided toward the bottom of the vehicle along the first inclined portion and is caused to flow to the lower end of the vertical wall portion. This reduces energy loss compared to when the underfloor traveling wind directly hits the vertical wall portion, and makes it possible to guide the underfloor traveling wind toward the bottom of the vehicle.

[0015] In one embodiment of the present invention, a notch extending in the vehicle width direction is provided rearward of the first inclined portion at the same position in the vehicle width direction as the first inclined portion. According to the above configuration, by providing the cutout portion, it is possible to promote bending deformation of the connecting member during a vehicle side collision. Also, since the underfloor traveling wind is guided to the vehicle bottom by the first inclined portion so that the underfloor traveling wind does not enter the cutout portion, it is possible to suppress turbulence of the underfloor traveling wind caused by the cutout portion.

[0016] In one embodiment of the present invention, the connecting member is provided at the front of the vehicle with an undercover that covers the underside of the vehicle, and a second inclined portion is provided at the rear end of the undercover, which slopes downward toward the rear, and the front end of the first inclined portion, which is located at the rear of the vehicle relative to the second inclined portion, is located rearward of the front end of the connecting member, and a guide portion is formed between the front end of the first inclined portion and the front end of the connecting member to guide the detached air detached by the undercover to the first inclined portion.

[0017] According to the above configuration, the wind detached by the under-cover is guided to the first inclined portion by the guide portion, and then guided toward the bottom of the vehicle by the first inclined portion, thereby preventing underfloor running wind from flowing into the space above the connecting member, thereby improving aerodynamic performance.

[0018] In one embodiment of the present invention, a ridge portion is formed between the slope portion and a flat portion adjacent to the slope portion on the vehicle width directional outer side, and the ridge portion is formed so as to extend toward the vehicle width directional outer side toward the rear of the vehicle.

[0019] According to the above configuration, the underfloor traveling wind flowing through the above-mentioned flat portion is guided along the ridge portion toward the outside in the vehicle width direction and flows toward the battery unit, thereby suppressing the flow of the underfloor traveling wind that attempts to flow inside the protruding member. Effect of the Invention

[0020] According to this invention, it is possible to prevent the battery unit from being pinched and deformed between the connecting member and the side sill during a vehicle side collision, and it is also possible to prevent underfloor wind from entering between the battery units. [Brief description of the drawings]

[0021] [Figure 1] 1 is a bottom view of a main portion of a vehicle equipped with a vehicle undercarriage structure of the present invention; [Diagram 2] FIG. 2 is a perspective view showing the structure of FIG. 1 as viewed from below the vehicle. [Diagram 3]Cross-sectional view taken along line AA in FIG. [Figure 4] FIG. 2 is a cross-sectional view taken along line BB in FIG. 1 . [Diagram 5] FIG. [Figure 6] FIG. [Figure 7] FIG. 6 is a cross-sectional view taken along line DD in FIG. 5 . [Figure 8] 6 is a cross-sectional view taken along line EE in FIG. 5 . [Figure 9] FIG. 2 is a bottom view of a main portion of the vehicle underbody structure with an undercover attached. [Figure 10] 10(a) is a cross-sectional view taken along line G-G in FIG. 9, and (b) is an enlarged view of a portion of FIG. 10(a). [Figure 11] FIG. 2 is a bottom view showing a state in which the undercarriage of the vehicle according to the embodiment is subjected to a side collision. [Figure 12] FIG. 12 is a longitudinal sectional view of the main part of FIG. [Figure 13] FIG. 4 is a bottom view showing the undercarriage of a vehicle according to a comparative example. [Figure 14] FIG. 4 is a bottom view showing a state in which a side collision occurs in the undercarriage of a vehicle of a comparative example. [Figure 15] FIG. 15 is a longitudinal sectional view of the main part of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] The objectives of preventing the battery unit from being pinched and deformed between the connecting member and the side sill in the event of a side collision of the vehicle, and preventing underfloor traveling wind from entering between the battery units, are achieved by a structure comprising a side sill extending in the fore-and-aft direction of the vehicle on the outer side in the vehicle width direction, a first battery unit and a second battery unit arranged adjacent to the inner side in the vehicle width direction of the side sill and below the floor panel, spaced apart in the vehicle width direction, and a connecting member connecting between the first battery unit and the second battery unit, the connecting member comprising a vertical wall portion extending in the vehicle width direction and protruding below the vehicle, and a slope portion behind the vertical wall portion that inclines downwardly towards the vehicle as it approaches the rear, and the lower end of the slope portion is configured to be located lower than the lower end of the vertical wall portion. EXAMPLES

[0023] An embodiment of the present invention will now be described in detail with reference to the accompanying drawings. The drawings show the undercarriage of a vehicle, with Fig. 1 being a bottom view of a key portion of the vehicle equipped with the undercarriage, more specifically, a bottom view showing the undercarriage at a position corresponding to the center pillar and its fore-and-aft surroundings, Fig. 2 being an oblique view showing the structure of Fig. 1 as seen from below the vehicle, Fig. 3 being a cross-sectional view taken along line AA in Fig. 1, and Fig. 4 being a cross-sectional view taken along line BB in Fig. 1.

[0024] 5 is a bottom view of the connecting member, FIG. 6 is a bottom oblique view of the connecting member, FIG. 7 is a cross-sectional view taken along line DD in FIG. 5, FIG. 8 is a cross-sectional view taken along line EE in FIG. 5, FIG. 9 is a bottom view of a key portion of the vehicle's lower structure with the undercover attached, FIG. 10(a) is a cross-sectional view taken along line G-G in FIG. 9, and FIG. 10(b) is a partially enlarged view of FIG. 10(a).

[0025] In the figure, arrow F indicates the front of the vehicle, arrow R indicates the rear of the vehicle, arrow LE indicates the left outer side in the vehicle width direction, arrow RI indicates the right outer side in the vehicle width direction, and arrow UP indicates the top of the vehicle.

[0026] As shown in Fig. 3, a side sill 1 is provided as a vehicle body strength member extending in the front-rear direction of the vehicle on both the left and right outer sides in the vehicle width direction. This side sill 1 has a side sill closed cross section 4 extending in the front-rear direction of the vehicle by joining and fixing a side sill outer 2 and a side sill inner 3. In this embodiment, a center pillar inner 5 is sandwiched between the side sill outer 2 and the side sill inner 3 at the center pillar installation site.

[0027] Instead of the structure in which the center pillar is sandwiched between the side sill outer panel 2 and the side sill inner panel 3, a structure in which a side sill reinforcement is sandwiched between these two panels 2, 3 may be adopted.

[0028] As shown in Figures 2 and 3, the center pillar 6 is a vehicle body strength component having a center pillar closed cross-section extending in the vertical direction of the vehicle by joining and fixing a center pillar inner 5 (see Figure 3) and a center pillar outer 7 (see Figure 2), and this center pillar 6 connects the roof side rail and the side sill 1 in the vertical direction.

[0029] As shown in Fig. 3, a floor panel 8 constituting the floor surface of the vehicle compartment is provided between the side sill inners 3, 3 of a pair of left and right side sills 1, and a tunnel portion 9 extending in the front-rear direction of the vehicle is provided in the center in the vehicle width direction of this floor panel 8. This tunnel portion 9 may be formed integrally with the floor panel 8, or a structure in which a separate tunnel portion 9 is attached to the floor panel 8 may be adopted.

[0030] As shown in Figures 3 and 4, tunnel reinforcements 10 (so-called high mount backbone frames) are attached to the upper left and right corners of the above-mentioned tunnel section 9, which protrudes into the vehicle interior and extends in the fore-and-aft direction of the vehicle, and an upper tunnel closed cross section 11 extending in the fore-and-aft direction of the vehicle is formed between this tunnel reinforcement 10 and tunnel section 9, thereby improving the rigidity of the tunnel section.

[0031] As shown in Figures 3 and 4, tunnel side members 12 are attached to the lower left and right corners of the above-mentioned tunnel section 9, and a lower tunnel closed cross section 13 extending in the fore-and-aft direction of the vehicle is formed between these tunnel side members 12 and the tunnel section 9, thereby improving the rigidity of the tunnel section.

[0032] As shown in Figures 1 and 2, an underfloor floor frame 14 with an inverted Hat-shaped cross section is attached to both the left and right sides of the floor panel 8 and on the inside of the side sill inner 3 in the vehicle width direction, and a floor frame closed cross section 14a (see Figure 3) extending in the fore-and-aft direction of the vehicle is formed between the underside of the floor panel 8 and the underfloor floor frame 14, thereby improving floor rigidity. The under-floor floor frame 14 described above extends in the front-rear direction of the vehicle from the front end of the floor panel 8 to a predetermined position on the floor panel 8 corresponding to the rear portion of the center pillar 6 .

[0033] 1 and 2, a pair of left and right rear side frames 15 are provided that extend rearward from the rear ends of the underfloor floor frames 14 to a rear end panel (not shown). The rear side frames 15 are vehicle body strength members provided on both sides of the rear seat pan 16 and the luggage compartment floor in the vehicle width direction, and a closed cross section of the rear side frames that extends in the front-rear direction of the vehicle is formed between the rear side frames 15 and the rear floor (rear seat pan 16, luggage compartment floor).

[0034] As shown in FIG. 1, the rear portion of the side sill 1 and the front portion of the rear side frame 15 are configured to overlap in the vehicle width direction. In this embodiment, a PHEV (plug-in hybrid electric vehicle) is exemplified as the vehicle, and the vehicle is provided with the above-mentioned tunnel section 9 in order to guide exhaust gas emitted from an engine mounted at the front of the vehicle to the rear of the vehicle.

[0035] As shown in FIG. 3, left and right battery units 21, 22, i.e., a first battery unit 21 and a second battery unit 22, are provided adjacent to the inner side in the vehicle width direction of the above-mentioned side sill 1 and below the floor panel 8, separated by a tunnel portion 9 and spaced apart in the vehicle width direction.

[0036] As shown in FIG. 3, each of the first and second battery units 21, 22 described above includes a battery 18 consisting of a plurality of battery modules 17, a battery tray 23 having a concave cross-section that covers the lower part of the battery 18, and a battery cover 24 having an inverted concave cross-section that covers the upper part of the battery 18.

[0037] That is, in each of the first and second battery units 21, 22, the battery 18 is supported by a battery tray 23, and the battery 18 is disposed in a battery storage space 25 surrounded by the battery tray 23 and a battery cover 24. Moreover, the bottom surface of the battery tray 23 in each of the battery units 21, 22 described above is formed to be approximately flat in consideration of aerodynamic performance (see FIG. 3).

[0038] As shown in Figures 1 and 2, a connector connection portion 26 is provided at the bottom of first battery unit 21, at the front inside in the vehicle width direction, and a high-voltage cable 28 is configured to connect between an inverter 27, which serves as a high-voltage device provided in front of first battery unit 21, and the above-mentioned connector connection portion 26.

[0039] The high-voltage cable 28 described above is equipped with an inverter-side connector 29 and a battery-side connector 30 at its front and rear ends, and the inverter-side connector 29 is connected to the inverter 27, and the battery-side connector 30 is connected to the connector connection portion 26. The high-voltage cable 28 described above is routed so as to extend from the front of the first battery unit 21 toward the inverter 27 toward the front of the vehicle.

[0040] The above-mentioned inverter 27 is a power conversion device that obtains AC power from DC power of the battery 18, and this is for driving the wheels with an AC motor in order to increase the efficiency of the motor drive system.

[0041] As shown in FIG. 1, a relay unit 31 that switches an electric circuit of the vehicle is fixed to at least one of the first battery unit 21 and the second battery unit 22. In this embodiment, a plurality of relays 33, 34, 35, and 36 are attached to the back surface of a junction box 32 that is erected at the rear of the first battery unit 21 located on the left side of the vehicle, and these relays 33 to 36 constitute the relay section 31 described above.

[0042] Here, the above-mentioned relay 33 is a negative side quick charging relay, relay 34 is a positive side quick charging relay, relay 35 is a negative side normal charging relay, and relay 36 is a positive side normal charging relay, but the types of relays 33 to 36 are not limited to this.

[0043] Next, the support structure for the battery units 21 and 22 will be described with reference to FIGS. The vehicle width direction outer sides of the above-mentioned first battery unit 21 and second battery unit 22, which are heavy objects, are fixed to the vehicle body by intermediate fixing member 37 and rear fixing member 38 shown in Figs. Furthermore, the inner sides of the first battery unit 21 and the second battery unit 22 in the vehicle width direction are suspended and supported by the vehicle body by suspension members 43 (see FIG. 4) described later.

[0044] As shown in Figures 1 to 3, the above-mentioned intermediate fixing member 37 fixes the vehicle fore-and-aft direction intermediate portion of each battery unit 21, 22 to the vehicle body, and as shown in Figures 1 to 3, the intermediate fixing member 37 has a battery side mounting portion 37a and a vehicle body side mounting portion 37b.

[0045] The battery-side mounting portion 37a of the intermediate fixing member 37 is fastened to the side surface of the battery tray 23 of each battery unit 21, 22 by using a plurality of fastening members 39 such as bolts (see Figs. 1 and 2). The vehicle-body-side mounting portion 37b is fastened to the underside of the underfloor frame 14, which is the vehicle body frame, by using a plurality of fastening members 40 such as bolts and nuts (see Fig. 3).

[0046] The intermediate fixing member 37 is formed by an extrusion molding of aluminum or an aluminum alloy, with the battery side mounting portion 37a being formed into a solid structure and the vehicle body side mounting portion 37b being formed into a hollow structure.

[0047] In addition, since the upper surface of the hollow structure vehicle body side mounting portion 37b described above is fastened to the underfloor floor frame 14, the lower surface of the hollow structure vehicle body side mounting portion 37b is formed with a plurality of openings 37c for inserting the fastening members 40 therethrough (see Figures 1 and 2).

[0048] In this embodiment, bolts and nuts are used as the above-mentioned fastening members 40, and the nuts are pre-welded and fixed to the upper surface of the bottom portion of the under-floor floor frame 14. The vehicle body side mounting portion 37b is attached to the under-floor floor frame 14 by screwing a bolt inserted from the opening 37c of the vehicle body side mounting portion 37b into the above-mentioned nut. Furthermore, the intermediate fixing member 37 also serves as an energy absorbing member that absorbs a side collision load during a vehicle side collision.

[0049] On the other hand, the above-mentioned rear fixing member 38 fixes the rear of each battery unit 21, 22 in the fore-and-aft direction of the vehicle to the vehicle body, and as shown in Figures 1 and 2, the rear fixing member 38 has a battery side mounting portion 38a and a vehicle body side mounting portion 38b.

[0050] 1 and 2, the battery-side mounting portion 38a of the rear fixing member 38 is fastened to the rear side surface of the battery tray 23 in each battery unit 21, 22 using fastening members 41 such as bolts. Moreover, the vehicle-body-side mounting portion 38b is fastened to the underside of the rear side frame 15, which is the vehicle body frame, using fastening members 42 such as bolts and nuts.

[0051] In this embodiment, a structure is exemplified in which the vehicle body side mounting portion 38b of the rear fixing member 38 is fixed to the underside of the rear side frame 15 using a single fastening member 42, but a structure in which the vehicle body side mounting portion 38b is fixed to the rear side frame 15 as the vehicle body frame using multiple fastening members 42, 42 may also be adopted. The inner sides of the above-mentioned first battery unit 21 and second battery unit 22, which are heavy objects, in the vehicle width direction are suspended and supported by the vehicle body by suspension members 43 shown in FIG.

[0052] Figure 4 is a cross-sectional view taken along line BB in Figure 1, where line BB in Figure 1 corresponds to the front side of center pillar 6, and line CC in Figure 1 corresponds to the rear side of center pillar 6. Also, while Figure 4 only shows the structure at line BB, at line CC, as at line BB, each battery unit 21, 22 is supported by being suspended from the vehicle body by hanging members 43, and therefore the cross-sectional view taken along line CC is omitted.

[0053] As shown in FIG. 4, the left and right hanging members 43, 43 that support the first battery unit 21 and the second battery unit 22 by suspending them from the vehicle body each have a battery side mounting portion 43a at the bottom of the hanging member 43 and a vehicle body side mounting portion 43b at the top of the hanging member 43.

[0054] As shown in FIG. 4, in each battery unit 21, 22, a flange portion 23b is integrally formed with the upper end of a side wall portion 23a extending upward from the inner side in the vehicle width direction of the battery tray 23, and a flange portion 24b is also integrally formed with the lower end of a side wall portion 24a extending downward from the inner side in the vehicle width direction of the battery cover 24.

[0055] With these flanges 24b, 23b abutting against each other in the vertical direction and the battery side mounting portion 43a at the bottom of the hanging member 43 placed on top of them, these three members 43a, 24b, 23b are fastened together using long bolts 44 and nuts 45 as fastening members. In other words, the three members 43a, 24b, 23b are fastened together by the bolts 44 and nuts 45 (fastening members).

[0056] As shown in FIG. 4, a bracket 46 is welded and fixed across the lower surface of the upper part of the tunnel portion 9 and the inner surface of the side of the tunnel portion 9, corresponding to the upper part of the battery hanging position by the hanging member 43. The vehicle body side mounting portion 43b at the top of the hanging member 43 is fastened and fixed to the mounting seat surface of the bracket 46 using fastening members such as bolts 47 and nuts 48.

[0057] In this embodiment, the above-mentioned nut 48 is preliminarily welded and fixed to the upper surface of the mounting seat of the bracket 46, and the bolt 47 is fastened to the above-mentioned nut 48 via the vehicle body side mounting portion 43b on the upper part of the hanging member 43, thereby fastening the vehicle body side mounting portion 43b to the mounting seat surface of the bracket 46.

[0058] As a result, the inner side of each battery unit 21, 22 in the vehicle width direction is suspended and supported by the tunnel section 9, which is a vehicle body strength member, via suspension members 43 at multiple points spaced apart in the front-rear direction middle of the vehicle.

[0059] Next, the insulator installation structure will be described with reference to FIGS. 1 to 4 and 8. FIG. 1 to 4, a front insulator 51, a middle insulator 52, and a rear insulator 53 are provided under the vehicle to cover the exhaust passage formed by the exhaust pipe. Each of these insulators 51, 52, and 53 is formed separately and attached to the vehicle body so as to be continuous in the front-to-rear direction of the vehicle.

[0060] 1 to 4, intermediate insulator 52 (so-called tunnel insulator) is located below tunnel portion 9 between first battery unit 21 and second battery unit 22. Front insulator 51 is located further forward of the vehicle than intermediate insulator 52 and offset to the right in the vehicle width direction from tunnel portion 9. Rear insulator 53 is located further rearward of the vehicle than intermediate insulator 52 and in the center in the vehicle width direction.

[0061] As shown in FIGS. 4 and 8, the intermediate insulator 52 is a protruding member that is located between the first battery unit 21 and the second battery unit 22 and protrudes upward from between the bottoms of the battery trays 23 of the battery units 21, 22.

[0062] This intermediate insulator 52 is integrally formed with a left side wall 52a, a right side wall 52b, an upper wall 52c connecting the upper parts of the side walls 52a, 52b in the vehicle width direction, and left and right flange portions 52d, 52e extending outward in the vehicle width direction from the lower ends of the side walls 52a, 52b.

[0063] The side walls 52a, 52b extend upward from the inner ends of the left and right flanges 52d, 52e in the vehicle width direction. That is, the side walls 52a, 52b extend in the vertical direction to connect the upper wall 52c to the left and right flanges 52d, 52e.

[0064] As shown in FIGS. 1 to 4, below the intermediate insulator 52, a connecting member 60 is provided to connect the first battery unit 21 and the second battery unit 22 in the vehicle width direction.

[0065] In detail, the above-mentioned connecting member 60 connects between the inner side in the vehicle width direction of the bottom wall of the battery tray 23 of the first battery unit 21 and the inner side in the vehicle width direction of the bottom wall of the battery tray 23 of the second battery unit 22 in the vehicle width direction (see FIG. 4).

[0066] Next, the arrangement structure of the under-cover will be described with reference to FIG. Fig. 1 is a bottom view showing the underbody structure of the vehicle with under-covers 54, 55, 56 removed, and Fig. 9 is a bottom view of the main parts of the underbody structure of the vehicle with under-covers 54, 55, 56 attached. As is clear from a comparison between Fig. 1 and Fig. 9, a front under-cover 54 that covers the underside of the vehicle is provided in front of the above-mentioned connecting member 60.

[0067] Further, a left undercover 55 is provided on the left side in the vehicle width direction of the connecting member 60, which covers the underside of the vehicle including the underside of the first battery unit 21. An inner end of the left undercover 55 in the vehicle width direction overlaps with a part of the left side of the connecting member 60 in the vehicle width direction (more specifically, each of the connecting portions 70, 71 described later).

[0068] Furthermore, a right undercover 56 is provided on the right side in the vehicle width direction of the connecting member 60, covering the underside of the vehicle including the underside of the second battery unit 22. An inner end of the right undercover 56 in the vehicle width direction overlaps a part of the right side of the connecting member 60 in the vehicle width direction (more specifically, right front connecting portions 72, 73 described later). As shown in FIG. 9, the connecting member 60 has a middle portion in the vehicle width direction, excluding a portion on the left side in the vehicle width direction and a portion on the right side in the vehicle width direction, exposed below the vehicle.

[0069] Next, the connecting member 60 and its surrounding structure will be described in detail. As shown in FIG. 5, the above-mentioned connecting member 60 is formed by pressing a plate-shaped base member 60B to integrally form the respective elements of the vertical wall portion 62 of the widthwise connecting portion 61, the diagonal connecting portion 63, the slope portion 64, the cutout portion 65, the guide portion 66, the flat portion 67, the plurality of first inclined portions 68, 69, and the plurality of ridge portions X1, X2.

[0070] That is, the above-mentioned connecting member 60 includes a vertical wall portion 62 of the vehicle width direction connecting portion 61, a diagonal connecting portion 63, a slope portion 64, a cutout portion 65, a guide portion 66, a flat portion 67, a plurality of first inclined portions 68, 69, and a plurality of ridge portions X1, X2.

[0071] 1 and 5, the vehicle width direction connecting portion 61 connects the front portions of these elements 21, 22 in the vehicle width direction so as to enable a side collision load to be transmitted in the vehicle width direction from the front portion of the first battery unit 21 to the front portion of the second battery unit 22. In this embodiment, the vehicle width direction connecting portion 61 is connected to the first battery unit 21 forward of the center of gravity of the first battery unit 21 via a left front connecting portion 70 described later.

[0072] As shown in Fig. 7, which is a cross section taken along line D-D in Fig. 5, the above-mentioned vehicle width direction connecting portion 61 is formed by a bead that protrudes downward, and this bead (vehicle width direction connecting portion 61) has a plurality of ridge lines X3, X4, X5, and X6, and the above-mentioned vertical wall portion 62 is formed between the two front ridge lines X3 and X4 among the plurality of ridge lines X3 to X6. This vertical wall portion 62 extends in the vehicle width direction and protrudes downward of the vehicle, as shown in Figs. 5 and 7.

[0073] 1 and 5, the above-mentioned diagonal connector 63 connects the second battery unit 22 to the rear of the first battery unit 21. In this embodiment, the above-mentioned diagonal connector 63 connects the front of the second battery unit 22 to the rear of the first battery unit 21 in a diagonal direction.

[0074] As shown in Figures 5 and 6, a left side front connecting portion 70 located at the left end in the vehicle width direction between the forward extension portion 61a on the first battery unit 21 side of the vehicle width direction connecting portion 61 and the rearward extension portion 61b is connected to the front of the first battery unit 21 by a plurality of bolts B1, B2 serving as fixing members spaced apart in the vehicle fore-and-aft direction.

[0075] Specifically, the left front connecting portion 70 is fixed to the bottom wall of the battery tray 23 in the front of the first battery unit 21 using a plurality of bolts B1, B2. More specifically, the left front connecting portion 70 is connected and fixed to the first battery unit 21 forward of the center of gravity of the vehicle.

[0076] As shown in Figures 5 and 6, the left side rear connecting portion 71, which is the rear connecting portion on the first battery unit 21 side of the diagonal connecting portion 63, is connected to the rear of the first battery unit 21 by a plurality of bolts B3, B4, B5, which serve as fixing members spaced apart in the fore-and-aft direction of the vehicle.

[0077] In detail, the above-mentioned left side rear connecting portion 71 is located rearward of the above-mentioned left side front connecting portion 70 in the vehicle fore-and-aft direction, and this left side rear connecting portion 71 is fixed to the bottom wall of the battery tray 23 at the rear of the first battery unit 21 using a plurality of bolts B3, B4, B5.

[0078] As shown in Figures 5 and 6, the right side front connecting portion 72, which is located at the right end portion in the vehicle width direction of the lateral extension portion 61c on the second battery unit 22 side of the vehicle width direction connecting portion 61, is connected to the front of the second battery unit 22 by a plurality of bolts B6, B7, B8 which serve as fixing members spaced apart in the vehicle fore-and-aft direction.

[0079] In detail, the right front coupling portion 72 is fixed to the bottom wall of the battery tray 23 in the front of the second battery unit 22 by a plurality of bolts B6, B7, B8.

[0080] Here, in this embodiment, the above-mentioned right side front coupling portion 72 also serves as a right side front coupling portion 73 that is the front coupling portion of the diagonal coupling portion 63 on the second battery unit 22 side. The above-mentioned slope portion 64 is formed in a so-called high-front-low-rear shape that slopes downward toward the rear of the vertical wall portion 62 (see FIG. 7).

[0081] As shown in FIG. 7, when the length of the connecting member 60 in the vehicle fore-and-aft direction, i.e., the overall length, is L2, the above-mentioned slope portion 64 is formed within a range of a fore-and-aft length L1 that is approximately 40% of the length L2 from the rear end 60a of the connecting member 60 toward the front middle portion of the connecting member 60.

[0082] 7, the lower end of the slope portion 64 (see the rear end 60a of the connecting member 60) is configured to be located lower on the vehicle than the lower end of the vertical wall portion 62. That is, as shown in the figure, there is a height difference ΔH between the lower end of the slope portion 64 and the lower end of the vertical wall portion 62. In other words, the lower end of the slope portion 64 is located lower than the lower end of the vertical wall portion 62 by the height difference ΔH.

[0083] In this way, by configuring the lower end of the slope portion 64 to be lower than the lower end of the vertical wall portion 62 by a height difference ΔH, the slope portion 64 is configured to guide underfloor traveling wind that cannot be completely separated by the vertical wall portion 62 downwards in the vehicle and separate it there.

[0084] In addition, since the height of the vertical wall portion 62 in the vehicle up-down direction is not increased, the vertical wall portion 62 does not hinder bending deformation of the connecting member 60 during a vehicle side collision. This suppresses the action of the connecting member 60 bracing itself against the battery unit on the side of the side collision load input (in this embodiment, the first battery unit 21), and suppresses deformation of the battery unit due to being pinched between the connecting member 60 and the side sill 1.

[0085] 8, the above-mentioned vehicle width direction outer end 64a on the right side of the rear end of the slope portion 64 is located at the same position in the vehicle width direction as the lower end 52g of the right side wall 52b extending in the up-down direction of the middle insulator 52 as a protruding member, or at a vehicle width direction outer position. In this embodiment, the vehicle width direction outer end 64a on the right side of the rear end of the slope portion 64 is located on the right side in the vehicle width direction outer side with respect to the position of the lower end 52g of the side wall 52b of the middle insulator 52.

[0086] The position of the vehicle width direction outer end 64a of the rear end of the slope portion 64 is configured to prevent the wind that has separated from the rear end of the slope portion 64 from entering inside the intermediate insulator 52.

[0087] As shown in Figures 5 and 6, the above-mentioned multiple first inclined portions 68, 69 are integrally formed in the front portion of the vertical wall portion 62 which serves as the front wall of the vehicle width direction connecting portion 61, and as shown in the same figures, the above-mentioned multiple first inclined portions 68, 69 are formed so as to incline downwardly on the vehicle as they approach the rear of the vehicle.

[0088] In this embodiment, the above-mentioned first inclined portions 68, 69 are formed by the hypotenuse of the triangle of beads 68B, 69B, which are deformation-promoting portions having an approximately right-angled triangular shape in a side view of the vehicle and are provided at the front of the vertical wall portion 62, and each of these beads 68B, 69B is provided in multiple places spaced apart in the vehicle width direction.

[0089] As a result, the underfloor traveling wind is guided toward the bottom of the vehicle along the multiple first inclined portions 68, 69 and is directed to the lower end of the vertical wall portion 62, thereby reducing energy loss compared to when the underfloor traveling wind directly hits the vertical wall portion 62, and is configured to guide the underfloor traveling wind toward the bottom of the vehicle.

[0090] In addition, by providing multiple beads 68B, 69B spaced apart in the vehicle width direction, during a vehicle side collision, such as a pole collision, the vehicle width direction connecting portion 61 of the connecting member 60 transmits the side collision load to the opposite side in the vehicle width direction, while the multiple beads 68B, 69B act as deformation triggers, bending and deforming the vehicle width direction connecting portion 61, thereby absorbing the side collision energy and suppressing deformation of the battery unit.

[0091] Furthermore, by providing multiple beads 68B, 69B as the deformation promoting portions, the vehicle width direction connecting portion 61 deforms at multiple locations in the vehicle width direction during a side collision of the vehicle, so that even if the battery unit is displaced relatively in the vertical direction, the connecting member 60 is not stiffened, and the load input to the battery unit is reduced.

[0092] In other words, the battery unit is configured to prevent being pinched between the connecting member 60 and the side sill 1, more specifically, between the connecting member 60 and the underfloor floor frame 14, in the event of a vehicle side collision, thereby suppressing deformation of the battery unit.

[0093] As shown in Figures 5 and 6, in this embodiment, two first inclined portions 68, 69 (in other words, beads 68B, 69B) are provided spaced apart in the vehicle width direction, and a notch portion 65 extending in the vehicle width direction is provided immediately behind the rear extension portion 61b rearward of the first inclined portion 68 at the same position in the vehicle width direction as one of the first inclined portions 68 located relatively to the left in the vehicle width direction. The provision of the above-mentioned notch 65 is configured to promote bending deformation of the connecting member 60 during a vehicle side collision.

[0094] As shown in FIG. 5, the above-mentioned cutout portion 65 is open on the outer left side in the vehicle width direction of the connecting member 60 and terminates at a position corresponding to the right end in the vehicle width direction of one bead 68B and is closed at that position.

[0095] In the event of a vehicle side collision, when the above-mentioned connecting member 60 is bent and deformed, if the above-mentioned cutout portion 65 does not exist, the portion further rearward of the rear extension portion 61b must also be bent, which requires a large amount of energy when bending, but due to the presence of the above-mentioned cutout portion 65, a large amount of energy is not required when bending, and the connecting member 60 can be easily bent. This allows the connecting member 60 to be configured to suppress tension without interfering with the bending behavior of the connecting member 60.

[0096] Furthermore, to prevent the underfloor traveling wind from entering the above-mentioned cutout portion 65, the above-mentioned first inclined portion 68 guides the underfloor traveling wind toward the bottom of the vehicle, thereby suppressing disturbance of the underfloor traveling wind caused by the cutout portion 65.

[0097] 5 and 6, the above-mentioned multiple ridge portions X1, X2 are formed between the above-mentioned slope portion 64 and the flat portion 67 adjacent to the left outer side in the vehicle width direction of the slope portion 64. These ridge portions X1, X2 extend parallel to each other in the vehicle front-rear direction from the rear wall 61d of the downwardly convex bead constituting the vehicle width direction connecting portion 61 to the starting point 64b of the slope portion 64 (see FIG. 7).

[0098] In addition, the above-mentioned multiple ridge portions X1, X2 are formed from the starting portion 64b to the rear end 60a of the connecting member 60 so as to extend toward the outside in the vehicle width direction toward the rear of the vehicle, and the distance between the multiple ridge portions X1, X2 is formed so as to gradually increase toward the rear of the vehicle. As a result, the portions between the ridge lines X1, X2 and the slope portion 64 are formed to have a shape that widens toward the left outer side in the vehicle width direction as it approaches the rear of the vehicle.

[0099] By forming the above-mentioned ridge portions X1, X2 so that they face outward in the vehicle width direction toward the rear of the vehicle, the underfloor traveling wind flowing along the above-mentioned flat portion 67 is guided outward in the vehicle width direction along the wall portion XW between the ridge portions X1, X2 and flows toward the first battery unit 21, thereby suppressing the flow of the underfloor traveling wind that attempts to flow into the inside of the middle insulator 52, which is a protruding member.

[0100] 9 and 10, a second inclined portion 54a that inclines downward toward the vehicle rear is provided at the rear end of the front under-cover 54 located in front of the connecting member 60. As shown in Fig. 10(a), in this embodiment, the second inclined portion 54a is inclined in a front-high, rear-low manner so that the angle between the main surface of the front under-cover 54 and the second inclined portion 54a is about 15 degrees, but is not limited to the above angle.

[0101] As shown in FIG. 10(b), front ends 68a, 69a of the first inclined portions 68, 69 located rearward of the second inclined portion 54a are positioned a distance ΔL rearward of the front end 60f of the connecting member 60 described above.

[0102] 10(a) and 10(b), a guide portion 66 is formed between the front ends 68a, 69a of the first inclined portions 68, 69 and the front end 60f of the connecting member 60, for guiding the separated airflow separated at the second inclined portion 54a of the front under-cover 54 to the first inclined portions 68, 69. The length of this guide portion 66 in the vehicle fore-and-aft direction corresponds to the distance ΔL.

[0103] Here, the above-mentioned guide portion 66 extends on the flat plate at the same height as the forward extending portion 61a. As a result, the wind detached by the second inclined portion 54a of the front under-cover 54 is guided by the above-mentioned guide portion 66 to the first inclined portions 68, 69, and then the underfloor running wind is guided downwardly by the first inclined portions 68, 69. As a result, the underfloor running wind is prevented from flowing into the space above the connecting member 60, specifically, into the hollow portion of the middle insulator 52 shown in FIG. 3, thereby improving the aerodynamic performance.

[0104] As shown in FIGS. 5 and 6, a plurality of bolts B3, B4, B5 serving as fixing members for connecting the left rear connecting portion 71 to the first battery unit 21 are provided spaced apart in the vehicle front-rear direction.

[0105] In the above-mentioned left side rear connecting portion 71, which is the connecting portion on the first battery unit 21 side of the diagonal connecting portion 63, a second bead 74 extending in the fore-and-aft direction of the vehicle is provided adjacent to the inner side in the vehicle width direction of the bolts B3, B4, B5 of the left side rear connecting portion 71, so as to avoid concentration of stress on a specific bolt B3 and to distribute the stress approximately evenly to each of the bolts B3, B4, B5, thereby ensuring the strength reliability of the connecting member 60.

[0106] 5 and 6, a plurality of bolts B6, B7, B8 serving as fixing members for connecting the right front connecting parts 72, 73 to the second battery unit 22 are also provided spaced apart in the vehicle front-rear direction.

[0107] As described above, the right front connecting portions 72, 73 serve both as the connecting portion of the vehicle width direction connecting portion 61 on the second battery unit 22 side and as the connecting portion of the diagonal direction connecting portion 63 on the second battery unit 22 side.

[0108] Furthermore, a third bead 75 extending in the fore-and-aft direction of the vehicle is provided adjacent to the inner side in the vehicle width direction of each of the above-mentioned bolts B6, B7, B8, thereby preventing concentration of stress on a specific bolt B8 and distributing the stress approximately evenly to each of the bolts B6, B7, B8, thereby ensuring the strength reliability of the connecting member 60.

[0109] As shown in Figures 5 and 6, a rigidity change portion 76 is provided extending in the vehicle width direction from the rear end portion of the above-mentioned third bead 75 along the rear wall 61d of the vehicle width direction connecting portion 61 to the corresponding position of the other first inclined portion 69.

[0110] As shown in Fig. 7, in this embodiment, the rigidity change portion 76 is formed by a bead that protrudes upward (a bead with a so-called upward convex structure). During a vehicle side collision, the left end of the rigidity change portion 76 in the vehicle width direction becomes a rigidity change point, and stress tends to concentrate at this rigidity change point, which effectively acts as a deformation hook. As a result, the rigidity change portion 76 can promote the bending deformation of the connecting member 60 during a vehicle side collision.

[0111] Next, the flow of underfloor running wind will be described with reference to FIG. As shown in Figure 10(a), the underfloor running wind e1 flowing along the underside of the front under-cover 54 from the front of the vehicle to the rear of the vehicle is guided under the vehicle by the second inclined portion 54a at the rear end of the front under-cover 54, and is separated at the separation point at the rear end of the second inclined portion 54a.

[0112] The detached wind e2 at the rear end of the above-mentioned front under-cover 54 abuts against the guide portion 66 in front of the front ends of the first inclined portions 68, 69, and the underfloor running wind e3 after abutment is guided toward the bottom of the vehicle along the inclination of the first inclined portions 68, 69, and the underfloor running wind e3 flows to the lower end of the vertical wall portion 62.

[0113] The underfloor running wind e4 that cannot be completely separated by the above-mentioned vertical wall portion 62 flows along the underside of the connecting member 60 from the front to the rear of the vehicle, is guided under the vehicle by the slope portion 64, and is then separated at the separation point at the rear end of the slope portion 64.

[0114] On the other hand, as shown in Figures 5 and 6, the underfloor traveling wind flowing through the flat portion 67 adjacent to the outside in the vehicle width direction of the slope portion 64 is guided outward in the vehicle width direction along the wall portion XW between the ridge portions X1, X2, and is guided toward the first battery unit 21 side, thereby suppressing the flow of the underfloor traveling wind that attempts to flow into the interior of the middle insulator 52.

[0115] Fig. 11 is a bottom view showing the state of the undercarriage of the vehicle of this embodiment in a side collision, Fig. 12 is a vertical cross-sectional view of the main parts of Fig. 11, Fig. 13 is a bottom view showing the undercarriage of the vehicle of the comparative example, Fig. 14 is a bottom view showing the state of the undercarriage of the vehicle of the comparative example in a side collision, and Fig. 15 is a vertical cross-sectional view of the main parts of Fig. 14. In Figs. 13 to 15, the same reference numerals are used to designate the same parts as in Figs. 1, 11 and 12, and detailed explanations thereof will be omitted.

[0116] Next, the operation during a side collision of a vehicle, such as a collision with a pole, will be described with reference to Figs. When a colliding object 80 such as a pole collides with the vehicle inward in the vehicle width direction in front of the center of gravity of the first battery unit 21 as shown in FIG. 11 from the normal state shown in FIG. 1, and a side impact load shown by arrow a in FIG. 11 is input, the side sill 1 deforms into a V-shape when viewed from the bottom of the vehicle.

[0117] As a result, a side impact load is input to the first battery unit 21 from a local location forward of its center of gravity position, causing the front of the first battery unit 21 to attempt to rotate and displace inward in the vehicle width direction, but the vehicle width direction connecting portion 61 of the connecting member 60 transmits the side impact load to the second battery unit 22, which is on the opposite side in the vehicle width direction.

[0118] The above-mentioned connecting member 60 has a vertical wall portion 62, but since the vertical height of this vertical wall portion 62 is not increased, the bending deformation of the connecting member 60 during a vehicle side collision is not hindered, and the vehicle width direction connecting portion 61 is bent and deformed into an inverted hat shape as shown in Fig. 12. As a result, the action of the connecting member 60 bracing itself against the first battery unit 21 can be suppressed, and the first battery unit 21 can be suppressed from being pinched and deformed between the connecting member 60 and the side sill 1.

[0119] In FIG. 11, reference numeral 81 denotes a catalytic converter, 82 denotes an exhaust pipe upstream of the catalytic converter 81, and 83 denotes an exhaust pipe downstream of the catalytic converter 81. 1, 11, and 12, in a comparative example shown in Figs. 13 to 15, the front of the first battery unit 21 and the front of the second battery unit 22 are connected by a front connecting member 91, and the rear of the first battery unit 21 and the rear of the second battery unit 22 are connected by a rear connecting member 92. That is, in the comparative example, the front and rear parts of the battery units 21, 22 are connected in the vehicle width direction by separate connecting members 91, 92 spaced apart in the vehicle front-rear direction. In addition, the front connecting member 91 described above has a front wall 91a extending in the vehicle width direction at a height that allows the separation of underfloor traveling wind.

[0120] In the structure of the comparative example, when a colliding object 80 such as a pole collides with the vehicle inward in the vehicle width direction in front of the center of gravity of the first battery unit 21 as shown in FIG. 14 from the normal state shown in FIG. 13 and a side impact load shown by arrow a in FIG. 14 is input, the side sill 1 deforms into a V-shape when viewed from the bottom of the vehicle.

[0121] As a result, a side collision load is input to the first battery unit 21 from a local portion forward of the center of gravity, causing the front of the first battery unit 21 to pivotally displace inward in the vehicle width direction. In this case, since the front portion of the first battery unit 21 and the front portion of the second battery unit 22 are connected in the vehicle width direction by the front connecting member 91 described above, the side collision load can be transmitted via the front connecting member 91 to the second battery unit 22 on the opposite side in the vehicle width direction.

[0122] However, as shown in FIG. 15, due to its high rigidity, the front connecting member 91 bends at one location in the middle in the vehicle width direction, forming a V-shape when viewed from the front of the vehicle, restricting the vertical displacement of the first battery unit 21. The bend point 91b shown in FIG. 15 and the fixed point 91c of the front connecting member 91 to the first battery unit 21 act to tension the first battery unit 21, causing the first battery unit 21 to be pinched between the front connecting member 91 and the side sill 1, and deforming the first battery unit 21, which is not preferable.

[0123] In contrast to the structure of the comparative example shown in Figures 13 to 15, in this embodiment shown in Figures 1, 11 and 12, the height of the vertical wall portion 62 is not increased, so that the bending deformation of the connecting member 60 during a vehicle side collision is not hindered, and the action of the connecting member 60 bracing itself against the first battery unit 21 can be suppressed, thereby absorbing the side collision energy and suppressing deformation of the first battery unit 21.

[0124] As described above, the undercarriage structure of the vehicle in the above embodiment comprises a side sill 1 extending in the fore-and-aft direction of the vehicle on the outer side in the vehicle width direction, a first battery unit 21 and a second battery unit 22 adjacent to the inner side in the vehicle width direction of the side sill 1 and spaced apart in the vehicle width direction below the floor panel 8, and a connecting member 60 connecting between the first battery unit 21 and the second battery unit 22, the connecting member 60 comprising a vertical wall portion 62 extending in the vehicle width direction and protruding downwardly of the vehicle, and a slope portion 64 behind the vertical wall portion 62 and inclined downwardly towards the vehicle as it approaches the rear, and the lower end of the slope portion 64 is configured to be positioned lower than the lower end of the vertical wall portion 62 (see Figures 1, 5, 6 and 7).

[0125] According to this configuration, the lower end of the slope portion 64 is configured lower than the lower end of the vertical wall portion 62, so that underfloor traveling wind that cannot be completely separated by the vertical wall portion 62 can be guided downwards in the vehicle by the slope portion 64 and separated therefrom.

[0126] Furthermore, since the vertical wall portion 62 is not made high, the bending deformation of the connecting member 60 during a vehicle side collision is not hindered, and the action of the connecting member 60 bracing itself against the battery unit (first battery unit 21) on the side of the side collision load input can be suppressed, thereby preventing the battery unit (first battery unit 21) from being pinched between the connecting member 60 and the side sill 1 and deforming.

[0127] In one embodiment of the present invention, a protruding member (middle insulator 52) is provided between the first battery unit 21 and the second battery unit 22, protruding upward from between the bottoms of these battery units 21, 22, and the vehicle width direction outer end portion 64a of the rear end of the slope portion 64 is located at the same position as the lower end 52g of the side wall 52b extending in the vertical direction of the protruding member (middle insulator 52) or at a vehicle width direction outer position (see Figure 8).

[0128] According to this configuration, the position of the vehicle width direction outer end 64a of the rear end of the slope portion 64 can prevent the detached wind from the rear end of the slope portion 64 from entering inside the above-mentioned protruding member (middle insulator 52).

[0129] In one embodiment of the present invention, the front portion of the vertical wall portion 62 is provided with first inclined portions 68, 69 that are inclined downward toward the rear of the vehicle (see Figs. 6 and 10). According to this configuration, the underfloor traveling wind is guided toward the bottom of the vehicle along the first inclined portions 68, 69 and is caused to flow to the lower end of the vertical wall portion 62. As a result, energy loss is reduced compared to when the underfloor traveling wind directly hits the vertical wall portion 62, and the underfloor traveling wind can be guided toward the bottom of the vehicle.

[0130] In one embodiment of the present invention, a notch 65 extending in the vehicle width direction is provided behind the first inclined portion 68 at the same position in the vehicle width direction as the first inclined portion (in this embodiment, one of the multiple first inclined portions 68, 69) (see Figures 5 and 6).

[0131] According to this configuration, by providing the above-mentioned cutout portion 65, it is possible to promote bending deformation of the connecting member 60 during a vehicle side collision. Also, since the above-mentioned first inclined portion 68 guides the underfloor traveling wind toward the bottom of the vehicle so that the underfloor traveling wind does not enter the above-mentioned cutout portion 65, it is possible to suppress turbulence of the underfloor traveling wind caused by the cutout portion 65.

[0132] In one embodiment of the present invention, the connecting member 60 is provided at the front of the vehicle with an undercover (front undercover 54) that covers the underside of the vehicle, and the rear end of the undercover (front undercover 54) is provided with a second inclined portion 54a that inclines downward toward the rear, and the front ends 68a, 69a of the first inclined portions 68, 69 that are located at the rear of the vehicle relative to the second inclined portion 54a are located rearward of the front end 60f of the connecting member 60, and a guide portion 66 is formed between the front ends 68a, 69a of the first inclined portions 68, 69 and the front end 60f of the connecting member 60 to guide the detached air that has detached from the undercover (front undercover 54) to the first inclined portions 68, 69 (see Figures 9 and 10).

[0133] According to this configuration, the wind detached by the undercover (front undercover 54) is guided by the guide portion 66 to the first inclined portions 68, 69, and then guided toward the bottom of the vehicle by the first inclined portions 68, 69, thereby preventing the underfloor running wind from flowing into the space above the connecting member 60 (see the hollow portion in the middle insulator 52), thereby improving aerodynamic performance.

[0134] In one embodiment of the present invention, ridge portions X1, X2 are formed between the slope portion 64 and a flat portion 67 adjacent to the slope portion 64 on the vehicle width direction outer side, and the ridge portions X1, X2 are formed so as to extend toward the outer side in the vehicle width direction toward the rear of the vehicle (see Figures 5 and 6).

[0135] According to this configuration, the underfloor traveling wind flowing through the above-mentioned flat portion 67 is guided outward in the vehicle width direction along the above-mentioned ridge portions X1, X2 (more specifically, the wall portion XW between the ridge portions X1, X2) and flows toward the battery unit side (the first battery unit 21 side), thereby making it possible to suppress the flow of the underfloor traveling wind that attempts to flow into the inside of the protruding member (the middle insulator 52).

[0136] In the configuration of the present invention and the above-mentioned embodiment, The protruding member of the present invention corresponds to the intermediate insulator 52 of the embodiment. Similarly, The under cover corresponds to the front under cover 54, The present invention is not limited to the configurations of the above-described embodiments. [Industrial Applicability]

[0137] INDUSTRIAL APPLICABILITY As described above, the present invention is useful for a vehicle understructure in which a battery unit is mounted under the floor. [Explanation of symbols]

[0138] 1...Side sill 8…Floor panel 21…1st battery unit 22…Second battery unit 52...Middle insulator (protruding member) 52b…Side wall 52g…Bottom edge of side wall 54...Front undercover (undercover) 54a…Second slope part 60...Connecting member 60f…front end 62...Vertical wall part 64…Slope section 64a…Outer end in the vehicle width direction 65…Notch 66…Guide section 67…Plane part 68,69...1st slope part 68a,69a...front end X1,X2…Ridge line part

Claims

1. A side sill extending in a vehicle front-rear direction on an outer side in a vehicle width direction; a first battery unit and a second battery unit provided adjacent to an inner side of the side sill in a vehicle width direction and spaced apart from each other in a vehicle width direction under a floor panel; a connecting member connecting the first battery unit and the second battery unit, The connecting member includes a vertical wall portion extending in the vehicle width direction and protruding downwardly of the vehicle; a slope portion inclined toward the vehicle downward toward the rear at the rear of the vertical wall portion, The lower end of the slope portion is configured to be located lower on the vehicle than the lower end of the vertical wall portion. The undercarriage of the vehicle.

2. a protruding member is provided between the first battery unit and the second battery unit, the protruding member protruding upward from between bottom portions of the first battery unit and the second battery unit; The outer end of the rear end of the slope portion in the vehicle width direction is located at the same position as the lower end position of the side wall extending in the vertical direction of the protruding member, or at an outer position in the vehicle width direction. The vehicle underbody structure according to claim 1 .

3. A first inclined portion is provided at the front of the vertical wall portion, the first inclined portion being inclined downward toward the rear of the vehicle.

3. The vehicle underbody structure according to claim 1 or 2.

4. A notch extending in the vehicle width direction is provided behind the first inclined portion at the same position in the vehicle width direction as the first inclined portion.

4. The vehicle underbody structure according to claim 3.

5. An undercover is provided on the front side of the connecting member to cover the underside of the vehicle, a second inclined portion inclined toward the vehicle downward as it approaches the rear end of the undercover; a front end of the first inclined portion, which is located rearward of the vehicle relative to the second inclined portion, is located rearward of a front end of the connecting member, A guide portion is formed between a front end of the first inclined portion and a front end of the connecting member, the guide portion guiding the air separated from the under-cover to the first inclined portion.

5. The vehicle underbody structure according to claim 3 or 4.

6. A ridge portion is formed between the slope portion and a flat portion adjacent to the slope portion on an outer side in a vehicle width direction, The ridgeline is formed so as to extend outward in the vehicle width direction toward the rear of the vehicle. The vehicle underbody structure according to any one of claims 1 to 5.

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