JP7613264B2 - Vehicle undercarriage - Google Patents

Description

This invention relates to a vehicle undercarriage structure in which a battery unit is mounted under the floor.

As disclosed in Patent Document 1, a tunnel member is known that is provided to prevent underfloor wind from flowing into the floor tunnel while the vehicle is moving, thereby improving aerodynamic performance.

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 tries to enter the interior of the floor tunnel section downwards in the vehicle, improving aerodynamic performance.

On the other hand, in the case of a PHEV (plug-in hybrid electric vehicle), 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.

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 bottom of each of the left and right battery units, it becomes possible to separate the underfloor traveling wind that occurs between the left and right battery units.

However, if a connecting member with a vertical dimension large enough to allow for separation of the wind from underfloor travel is used, a new problem arises in that in the event of a vehicle side collision, the connecting member becomes tense and the battery unit on the side receiving the side impact load becomes pinched between the connecting member and the side sill, causing the battery unit to deform.

JP 2016-132399 A

Therefore, the purpose of this invention is to provide a vehicle undercarriage structure that prevents the battery unit from being pinched and deformed between the connecting member and the side sill during a vehicle side collision, and also prevents underfloor wind from entering between the battery units.

The vehicle undercarriage structure according to the present invention comprises a side sill extending in the front-rear direction of the vehicle on the outer side in the vehicle width direction, a first battery unit and a second battery unit 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 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 downwardly of the vehicle, and a slope portion behind the vertical wall portion that slopes downwardly on the vehicle as it approaches the rear, the lower end of the slope portion being configured to be located lower on the vehicle than the lower end of the vertical wall portion.

With the above configuration, the lower end of the slope section is configured to be lower than the lower end of the vertical wall section, so that the underfloor running wind that cannot be completely separated by the vertical wall section can be guided to the bottom of the vehicle by the slope section and separated therefrom.

In addition, because the vertical wall portion is not made taller, the bending deformation of the connecting member during a vehicle side collision is not hindered, and the action of the connecting member bracing itself against the battery unit on the side where the side collision load is input can be suppressed, and the battery unit can be prevented from being pinched and deformed between the connecting member and the side sill.

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 the 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.

With the above configuration, the position of the outer end of the rear end of the slope section in the vehicle width direction can prevent the wind that has separated from the rear end of the slope section from entering inside the protruding member described above.

In one embodiment of the present invention, the front portion of the vertical wall portion is provided 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 under 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 under the vehicle.

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-mentioned configuration, by providing the cutout portion, it is possible to promote bending deformation of the connecting member in the event of a vehicle side collision. Also, since the underfloor traveling wind is guided to the underside of the vehicle by the first inclined portion so that the underfloor traveling wind does not enter the cutout portion, it is possible to suppress disturbance of the underfloor traveling wind caused by the cutout portion.

In one embodiment of the present invention, the vehicle front of the connecting member is provided with an undercover that covers the underside of the vehicle, and the rear end of the undercover is provided with a second inclined portion that inclines downward toward the rear, and the front end of the first inclined portion, which is located rearward 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 wind that has been detached by the undercover to the first inclined portion.

According to the above configuration, the wind detached by the undercover is guided to the first inclined portion by the guide portion, and then guided to the bottom of the vehicle by the first inclined portion, so that the wind caused by running under the floor is prevented from flowing into the space above the connecting member, improving the aerodynamic performance.

In one embodiment of the present invention, a ridgeline is formed between the sloped portion and the flat portion adjacent to the sloped portion on the outer side in the vehicle width direction, and the ridgeline is formed so as to extend outward in the vehicle width direction toward the rear of the vehicle.

According to the above configuration, the underfloor traveling wind flowing along the above-mentioned flat portion is guided outward in the vehicle width direction along the ridge line portion and flows toward the battery unit, thereby suppressing the flow of the underfloor traveling wind that attempts to flow into the inside of the protruding member.

This invention has the effect of preventing the battery unit from being pinched and deformed between the connecting member and the side sill during a vehicle side collision, and also preventing underfloor wind from entering between the battery units.

1 is a bottom view of a main portion of a vehicle equipped with a vehicle undercarriage structure of the present invention; FIG. 2 is a perspective view showing the structure of FIG. 1 as viewed from below the vehicle. 2 is a cross-sectional view taken along line AA in FIG. 1 . FIG. 2 is a cross-sectional view taken along line BB in FIG. 1 . FIG. FIG. 6 is a cross-sectional view taken along line DD in FIG. 5 . 6 is a cross-sectional view taken along line E-E of FIG. 5 . FIG. 2 is a bottom view of a main portion of the vehicle underbody structure with an undercover attached. 10A is a cross-sectional view taken along line G-G in FIG. 9, and FIG. 10B is a partially enlarged view of FIG. 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. FIG. 12 is a vertical cross-sectional view of the main part of FIG. 11 . FIG. 4 is a bottom view showing the undercarriage of a vehicle according to a comparative example. 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. FIG. 15 is a longitudinal sectional view of the main part of FIG. 14 .

The objectives of preventing the battery unit from being pinched between the connecting member and the side sill and deforming during a vehicle side collision, and preventing underfloor traveling wind from entering between the battery units, are achieved by a structure that includes a side sill extending in the front-rear direction of the vehicle on the outer side in the vehicle width direction, a first battery unit and a second battery unit that are 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 that connects the first battery unit and the second battery unit, the connecting member including a vertical wall portion that extends in the vehicle width direction and protrudes downwardly of the vehicle, and a slope portion that is inclined downwardly toward the rear of the vertical wall portion, the lower end of the slope portion being configured to be located lower than the lower end of the vertical wall portion.

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 viewed from below the vehicle, Fig. 3 being a cross-sectional view taken along line A-A in Fig. 1, and Fig. 4 being a cross-sectional view taken along line B-B in Fig. 1.

In addition, Figure 5 is a bottom view of the connecting member, Figure 6 is a bottom perspective view of the connecting member, Figure 7 is a cross-sectional view taken along line D-D in Figure 5, Figure 8 is a cross-sectional view taken along line E-E in Figure 5, Figure 9 is a bottom view of the main parts of the vehicle lower structure with the undercover attached, Figure 10(a) is a cross-sectional view taken along line G-G in Figure 9, and Figure 10(b) is a partially enlarged view of Figure 10(a).

In the figure, arrow F indicates the front of the vehicle, arrow R indicates the rear of the vehicle, arrow LE indicates the left outward direction in the vehicle width direction, arrow RI indicates the right outward direction in the vehicle width direction, and arrow UP indicates the top of the vehicle.

As shown in FIG. 3, a side sill 1 is provided as a vehicle body strength member extending in the longitudinal 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 that extends in the longitudinal 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.

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

As shown in Figures 2 and 3, the center pillar 6 is a vehicle body strength member that is made by joining and fixing the center pillar inner 5 (see Figure 3) and the center pillar outer 7 (see Figure 2) together and has a closed cross section that extends in the vertical direction of the vehicle. This center pillar 6 connects the roof side rail and the side sill 1 in the vertical direction.

As shown in FIG. 3, a floor panel 8 that constitutes the floor surface of the vehicle compartment is provided between the side sill inner panels 3, 3 of the pair of left and right side sills 1, and a tunnel section 9 that extends in the front-rear direction of the vehicle is provided in the center of the floor panel 8 in the vehicle width direction. This tunnel section 9 may be formed integrally with the floor panel 8, or a structure may be adopted in which a separate tunnel section 9 is attached to the floor panel 8.

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 tunnel section 9, which protrudes into the passenger compartment and extends in the fore-and-aft direction of the vehicle, and an upper closed cross section 11 of the tunnel is formed between the tunnel reinforcement 10 and the tunnel section 9, extending in the fore-and-aft direction of the vehicle, improving the rigidity of the tunnel section.

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

As shown in Figures 1 and 2, an underfloor floor frame 14 having 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 longitudinal 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 .

As shown in Figures 1 and 2, a pair of left and right rear side frames 15 are provided that extend rearward from the rear end of the above-mentioned underfloor floor frame 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 frame that extends in the fore-and-aft direction of the vehicle is formed between the rear side frames 15 and the rear floor (rear seat pan 16, luggage compartment floor).

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 portion 9 in order to guide exhaust gas discharged from an engine mounted at the front of the vehicle to the rear of the vehicle.

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

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

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

As shown in Figures 1 and 2, a connector connection part 26 is provided at the bottom of the 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 as a high-voltage device provided in front of the first battery unit 21 and the above-mentioned connector connection part 26.

The high-voltage cable 28 described above has an inverter-side connector 29 and a battery-side connector 30 at both front and rear ends. 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.

The inverter 27 mentioned above is a power conversion device that obtains AC power from the DC power of the battery 18. This is to drive the wheels with an AC motor in order to increase the efficiency of the motor drive system.

As shown in FIG. 1, a relay unit 31 for switching 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 above-mentioned relay section 31.

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.

Next, the support structure for the battery units 21, 22 will be described with reference to FIGS.
The outer sides in the vehicle width direction 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.
Further, 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.

As shown in Figures 1 to 3, the intermediate fixing member 37 described above fixes the intermediate portion of each battery unit 21, 22 in the vehicle front-rear direction 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.

The battery side mounting portion 37a of the intermediate fixing member 37 is fastened to the side of the battery tray 23 of each battery unit 21, 22 using multiple fastening members 39 such as bolts (see Figures 1 and 2). The vehicle side mounting portion 37b is fastened to the underside of the underfloor frame 14, which is the vehicle body frame, using multiple fastening members 40 such as bolts and nuts (see Figure 3).

The intermediate fixing member 37 is made of an aluminum or aluminum alloy extrusion, with the battery side mounting portion 37a being formed as a solid structure and the vehicle side mounting portion 37b being formed as a hollow structure.

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

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.

On the other hand, the rear fixing member 38 mentioned above fixes the rear of each battery unit 21, 22 in the vehicle front-rear direction 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.

As shown in Figures 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 multiple fastening members 41 such as bolts. The vehicle side mounting portion 38b is fastened to the underside of the rear side frame 15, which is the vehicle frame, using fastening members 42 such as bolts and nuts.

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 insides of the first battery unit 21 and the second battery unit 22 in the vehicle width direction, which are heavy objects, are suspended and supported by the vehicle body by suspension members 43 shown in FIG.

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

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 side mounting portion 43b at the top of the hanging member 43.

As shown in FIG. 4, in each battery unit 21, 22, a flange portion 23b is integrally formed at the upper end of the side wall portion 23a that extends upward from the inside in the vehicle width direction of the battery tray 23, and a flange portion 24b is integrally formed at the lower end of the side wall portion 24a that extends downward from the inside in the vehicle width direction of the battery cover 24.

These flanges 24b, 23b are abutted vertically, and the battery side mounting part 43a at the bottom of the hanging member 43 is placed on top of them. With this in place, the three parts 43a, 24b, 23b are fastened together using long bolts 44 and nuts 45 as fastening members. In other words, the three parts 43a, 24b, 23b are fastened together by the bolts 44 and nuts 45 (fastening members).

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 43 b at the top of the hanging member 43 is fastened and fixed to the mounting seat surface of the bracket 46 by using fastening members such as bolts 47 and nuts 48 .

In this embodiment, the above-mentioned nut 48 is preliminarily welded 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 part 43b at the top of the hanging member 43, thereby fastening the vehicle body side mounting part 43b to the mounting seat surface of the bracket 46.

As a result, the inside of each battery unit 21, 22 in the vehicle width direction is supported by hanging members 43 at multiple points spaced apart in the front-rear direction middle of the vehicle to the tunnel section 9, which is a vehicle body strength member.

Next, the insulator arrangement 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.

As shown in Figures 1 to 4, the middle insulator 52 (so-called tunnel insulator) is located below the tunnel section 9 between the first battery unit 21 and the second battery unit 22. The front insulator 51 is located further forward of the vehicle than the middle insulator 52 and offset to the right in the vehicle width direction from the tunnel section 9. The rear insulator 53 is located further rearward of the vehicle than the middle insulator 52 and in the center in the vehicle width direction.

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

The intermediate insulator 52 is integrally formed with a left side wall 52a, a right side wall 52b, an upper wall 52c that connects the upper parts of the side walls 52a, 52b in the vehicle width direction, and left and right flanges 52d, 52e that extend outward in the vehicle width direction from the lower ends of the side walls 52a, 52b.

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 upward and downward to connect the upper wall 52c to the left and right flanges 52d, 52e.

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

More specifically, the above-mentioned connecting member 60 connects the inside of the bottom wall of the battery tray 23 of the first battery unit 21 in the vehicle width direction to the inside of the bottom wall of the battery tray 23 of the second battery unit 22 in the vehicle width direction (see FIG. 4).

Next, the arrangement structure of the under-cover will be described with reference to FIG.
Fig. 1 is a bottom view showing the undercarriage of the vehicle with under-covers 54, 55, 56 removed, and Fig. 9 is a bottom view of the main part of the undercarriage 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.

In addition, a left undercover 55 is provided on the left side of the connecting member 60 in the vehicle width direction, covering the underside of the vehicle including the underside of the first battery unit 21. The 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 parts 70, 71 described later).

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.

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.

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 notch 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.

As shown in Figures 1 and 5, the above-mentioned vehicle width direction connecting portion 61 connects the front portions of these elements 21, 22 in the vehicle width direction so as to enable the transfer of a side collision load from the front portion of the first battery unit 21 to the front portion of the second battery unit 22 in the vehicle width direction. In this embodiment, the above-mentioned vehicle width direction connecting portion 61 is connected forward of the center of gravity of the first battery unit 21 via the left front connecting portion 70 described later.

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 multiple 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 of the multiple 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.

As shown in Figures 1 and 5, the diagonal connecting portion 63 connects the second battery unit 22 to the rear of the first battery unit 21. In this embodiment, the diagonal connecting portion 63 connects the front of the second battery unit 22 to the rear of the first battery unit 21 in a diagonal direction.

As shown in Figures 5 and 6, the left front connecting portion 70, which is 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 that serve as fixing members spaced apart in the vehicle front-rear direction.

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

As shown in Figures 5 and 6, the left 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, and B5, which serve as fixing members spaced apart in the vehicle front-rear direction.

In more detail, the left rear connecting part 71 is located rearward of the left front connecting part 70 in the vehicle longitudinal direction, and the left rear connecting part 71 is fixed to the bottom wall of the battery tray 23 at the rear of the first battery unit 21 using a number of bolts B3, B4, and B5.

As shown in Figures 5 and 6, the right-side front connecting portion 72, which is located at the right end 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, and B8 that serve as fixing members spaced apart in the vehicle front-rear direction.

More specifically, the right front connecting portion 72 is fixed to the bottom wall of the battery tray 23 at the front of the second battery unit 22 using a number of bolts B6, B7, and B8.

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

As shown in FIG. 7, when the length of the connecting member 60 in the vehicle longitudinal direction, i.e., the overall length, is L2, the above-mentioned slope portion 64 is formed within a range of a longitudinal 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.

Moreover, as shown in FIG. 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. In other words, 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.

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 to be separated.

In addition, because the height of the vertical wall portion 62 in the vertical direction of the vehicle is not increased, the vertical wall portion 62 does not hinder the bending deformation of the connecting member 60 during a vehicle side collision. This prevents the connecting member 60 from bracing against the battery unit on the side of the side collision load input (in this embodiment, the first battery unit 21), and prevents the battery unit from being pinched and deformed between the connecting member 60 and the side sill 1.

As shown in FIG. 8, the vehicle width direction outer end 64a on the right rear end of the slope portion 64 is located at the same position as the vehicle width direction position of 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 rear end of the slope portion 64 is located on the right outer side in the vehicle width direction relative to the lower end 52g of the side wall 52b of the middle insulator 52.

The position of the outer end 64a in the vehicle width direction of the rear end of the slope section 64 described above is configured to prevent the wind that has separated from the rear end of the slope section 64 from entering inside the intermediate insulator 52 described above.

As shown in Figures 5 and 6, the above-mentioned multiple first inclined portions 68, 69 are integrally formed with the front portion of the vertical wall portion 62 that serves as the front wall of the vehicle width direction connecting portion 61, and as shown in the figures, the above-mentioned multiple first inclined portions 68, 69 are formed so as to incline downward on the vehicle as they move toward the rear.

In this embodiment, the first inclined portions 68, 69 are formed by the hypotenuses of the beads 68B, 69B, which are deformation promoting portions that are provided at the front of the vertical wall portion 62 and have a substantially right-angled triangular shape in a side view of the vehicle, and these beads 68B, 69B are provided in multiples and spaced apart in the vehicle width direction.

This allows the underfloor wind to be guided downward along the first inclined portions 68, 69 and flow toward the lower end of the vertical wall portion 62, so that energy loss is reduced compared to when the underfloor wind hits the vertical wall portion 62 directly, and the underfloor wind is guided downward toward the vehicle.

In addition, by providing multiple beads 68B, 69B spaced apart in the vehicle width direction, in the event of 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 a deformation trigger, bending and deforming the vehicle width direction connecting portion 61, absorbing the side collision energy and suppressing deformation of the battery unit.

Furthermore, by providing multiple beads 68B, 69B as the deformation promoting portion, the vehicle width direction connecting portion 61 deforms at multiple points in the vehicle width direction during a vehicle side collision, so that even if the battery unit is displaced relative to the vehicle in the vertical direction, the connecting member 60 does not become stiff, and the load input to the battery unit is reduced.

In other words, the battery unit is prevented from 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, during a vehicle side collision, and deformation of the battery unit is prevented.

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 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.

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

When the above-mentioned connecting member 60 is bent and deformed during a vehicle side collision, if the above-mentioned cutout portion 65 does not exist, it is necessary to also break the portion further to the rear of the rear extension portion 61b, which requires a large amount of energy when folding. However, due to the presence of the above-mentioned cutout portion 65, it does not require a large amount of energy when folding, and it can be folded easily. This is configured to suppress tension of the connecting member 60 without hindering the folding behavior of the connecting member 60.

Moreover, to prevent the underfloor traveling wind from entering the above-mentioned notch 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 notch 65.

As shown in Figures 5 and 6, the above-mentioned multiple ridges X1 and X2 are formed between the above-mentioned slope portion 64 and the flat portion 67 adjacent to the slope portion 64 on the left outer side in the vehicle width direction. Each of these ridges X1 and X2 extends parallel to each other in the vehicle front-rear direction from the rear wall 61d of the downwardly convex bead that constitutes the vehicle width direction connecting portion 61 to the starting point 64b of the slope portion 64 (see Figure 7).

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 gradually increases 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.

By forming the above-mentioned ridge portions X1 and 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 and X2, and flows toward the first battery unit 21, thereby suppressing the flow of underfloor traveling wind that would otherwise flow into the middle insulator 52, which is a protruding member.

As shown in Figures 9 and 10, the rear end of the front undercover 54, which is located in front of the connecting member 60, is provided with a second inclined portion 54a that is inclined downward toward the rear of the vehicle. As shown in Figure 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 undercover 54 and the second inclined portion 54a is approximately 15 degrees, but this is not limited to the above angle.

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

As shown in Figures 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 wind detached at the second inclined portion 54a of the front undercover 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.

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.

As shown in Figures 5 and 6, a plurality of bolts B3, B4, and B5 are provided spaced apart in the fore-and-aft direction of the vehicle as fixing members that connect the left rear connecting portion 71 to the first battery unit 21.

The left rear connecting part 71 described above, which is the connecting part on the first battery unit 21 side of the diagonal connecting part 63, is provided with a second bead 74 extending in the longitudinal direction of the vehicle adjacent to the inside of the bolts B3, B4, and B5 of the left rear connecting part 71 in the vehicle width direction. This prevents stress from concentrating on a specific bolt B3, distributes the stress approximately evenly to each of the bolts B3, B4, and B5, and ensures the strength reliability of the connecting member 60.

As shown in Figures 5 and 6, a plurality of bolts B6, B7, and B8 are provided at intervals in the vehicle front-rear direction as fixing members that connect the right front connecting parts 72, 73 to the second battery unit 22.

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

A third bead 75 is provided adjacent to the inner side of each of the bolts B6, B7, and B8 in the vehicle width direction and extends in the vehicle front-rear direction, to prevent stress concentration on a specific bolt B8 and distribute the stress approximately evenly to each of the bolts B6, B7, and B8, thereby ensuring the strength reliability of the connecting member 60.

As shown in Figures 5 and 6, a stiffness change portion 76 is provided that extends in the vehicle width direction from the rear end of the 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.

As shown in FIG. 7, in this embodiment, the stiffness change portion 76 is formed by an upwardly protruding bead (a bead with a so-called upwardly convex structure). During a vehicle side collision, the left end of the stiffness change portion 76 in the vehicle width direction becomes a stiffness change point, and stress tends to concentrate at this stiffness change point, effectively acting as a deformation hook. As a result, the stiffness change portion 76 can promote the bending deformation of the connecting member 60 during a vehicle side collision.

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 detached at the detachment point at the rear end of the second inclined portion 54a.

The detached wind e2 at the rear end of the front undercover 54 contacts the guide portion 66 in front of the front end of the first inclined portions 68, 69, and the underfloor running wind e3 after contact is guided downward 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.

The underfloor running wind e4 that cannot be completely separated by the 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.

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

Figure 11 is a bottom view showing the state of the vehicle undercarriage of this embodiment in a side collision, Figure 12 is a vertical cross-sectional view of the main parts of Figure 11, Figure 13 is a bottom view showing the vehicle undercarriage of a comparative example, Figure 14 is a bottom view showing the state of the vehicle undercarriage of a comparative example in a side collision, and Figure 15 is a vertical cross-sectional view of the main parts of Figure 14. Note that in Figures 13 to 15, the same parts as in Figures 1, 11, and 12 are given the same reference numerals and detailed explanations are omitted.

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 from the normal state shown in FIG. 1 toward the inside in the vehicle width direction in front of the center of gravity of the first battery unit 21 as shown in FIG. 11 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.

As a result, a side impact load is input to the first battery unit 21 from a local area forward of its center of gravity, and the front of the first battery unit 21 attempts 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.

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 is not hindered during a vehicle side collision, 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 being stretched between 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.

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 the comparative example shown in Fig. 13 to 15, the front part of the first battery unit 21 and the front part of the second battery unit 22 are connected by a front connecting member 91, and the rear part of the first battery unit 21 and the rear part of the second battery unit 22 are connected by a rear connecting member 92. That is, in the comparative example, the front 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 above-mentioned front connecting member 91 has a front wall 91a extending in the vehicle width direction at a height that allows the separation of underfloor traveling wind.

In the comparative example structure, 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.

As a result, a side impact load is input to the first battery unit 21 from a localized area forward of its center of gravity, causing the front of the first battery unit 21 to pivotally displace inward in the vehicle width direction. In this case, because the front part of the first battery unit 21 and the front part of the second battery unit 22 are connected in the vehicle width direction by the front connecting member 91 described above, the side impact load can be transmitted via the front connecting member 91 to the second battery unit 22, which is on the opposite side in the vehicle width direction.

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, and the bending point 91b shown in FIG. 15 and the fixing point 91c of the front connecting member 91 to the first battery unit 21 act as a tension, so that the first battery unit 21 is pinched between the front connecting member 91 and the side sill 1, causing the first battery unit 21 to deform, which is not preferable.

In contrast to the comparative example structure 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, and the side collision energy can be absorbed and deformation of the first battery unit 21 can be suppressed.

In this way, the vehicle undercarriage structure of the above embodiment includes a side sill 1 extending in the vehicle front-rear direction 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 the first battery unit 21 and the second battery unit 22, the connecting member 60 including 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 that slopes downwardly on the vehicle as it approaches the rear, and the lower end of the slope portion 64 is configured to be located lower than the lower end of the vertical wall portion 62 (see Figures 1, 5, 6, and 7).

With 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 the underfloor running wind that cannot be completely separated by the vertical wall portion 62 can be guided to the bottom of the vehicle by the slope portion 64 and separated therefrom.

In addition, because the vertical wall portion 62 is not made taller, 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, and the battery unit (first battery unit 21) can be prevented from being pinched and deformed between the connecting member 60 and the side sill 1.

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 the battery units 21, 22, and the vehicle width direction outer end 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 FIG. 8).

With this configuration, the position of the outer end 64a in the vehicle width direction of the rear end of the slope section 64 can prevent the wind that has separated from the rear end of the slope section 64 from entering inside the protruding member (middle section insulator 52) described above.

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

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 first inclined portions 68, 69) (see Figures 5 and 6).

According to this configuration, by providing the above-mentioned notch portion 65, it is possible to promote the bending deformation of the connecting member 60 in the event of a vehicle side collision. In addition, since the above-mentioned first inclined portion 68 guides the underfloor traveling wind downwards of the vehicle so that the underfloor traveling wind does not enter the above-mentioned notch portion 65, it is possible to suppress the disturbance of the underfloor traveling wind caused by the notch portion 65.

In one embodiment of the present invention, the vehicle front of the connecting member 60 is provided 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. The front ends 68a, 69a of the first inclined portions 68, 69, which are located rearward of 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 wind detached from the undercover (front undercover 54) to the first inclined portions 68, 69 (see Figures 9 and 10).

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

In one embodiment of the present invention, ridges X1 and X2 are formed between the slope portion 64 and the flat portion 67 adjacent to the slope portion 64 on the vehicle widthwise outer side, and the ridges X1 and X2 are formed so as to extend toward the vehicle widthwise outer side toward the rear of the vehicle (see Figures 5 and 6).

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 and X2 (more specifically, the wall portion XW between the ridge portions X1 and X2) and flows toward the battery unit side (first battery unit 21 side), thereby suppressing the flow of the underfloor traveling wind that attempts to flow into the inside of the protruding member (middle insulator 52).

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.

As described above, the present invention is useful for vehicle undercarriage structures in which a battery unit is mounted under the floor.

1...Side sill 8...Floor panel 21...First battery unit 22...Second battery unit 52...Middle insulator (protruding member)
52b: Side wall 52g: Lower end of side wall 54: Front undercover (undercover)
54a... second inclined portion 60... connecting member 60f... front end 62... vertical wall portion 64... slope portion 64a... vehicle width direction outer end portion 65... notch portion 66... guide portion 67... flat portion 68, 69... first inclined portion 68a, 69a... front ends X1, X2... ridge portion

Claims (6)

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,
A vehicle underbody structure, characterized in that a lower end of the slope portion is positioned lower on the vehicle than a lower end of the vertical wall portion. 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;
2. The vehicle underbody structure according to claim 1, wherein the vehicle width direction outer end of the rear end of the slope portion is located at the same position as the lower end position of the vertically extending side wall of the protruding member or at a vehicle width direction outer position. 3. The vehicle underbody structure according to claim 1, further comprising a first inclined portion inclined downwardly toward the rear of the vehicle, the first inclined portion being provided at a front portion of the vertical wall portion. 4. The vehicle underbody structure according to claim 3, wherein a notch extending in the vehicle width direction is provided rearward of the first inclined portion at a position identical in the vehicle width direction to that of the first inclined portion. 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,
5. A vehicle underbody structure as described in claim 3 or 4, wherein a guide portion is formed between the front end of the first inclined portion and the front end of the connecting member, for guiding detached air detached from the undercover to the first inclined portion. 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,
6. The vehicle underbody structure according to claim 1, wherein the ridge portion is formed so as to extend outward in a vehicle width direction toward the rear of the vehicle.

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