Electric vehicle undercarriage

Abstract

This protects the battery pack, which is installed on the lower side of the floor, from impact loads. [Solution] The lower structure of the electric vehicle includes a battery pack 10 positioned between the side members, a hanger member 60 provided on the side member to which a trailing arm is connected, and a side bracket 70 extending from the hanger member 60 toward the side sill 40, wherein the rigidity of the side bracket 70 in the vehicle width direction is set lower than the rigidity of the hanger member 60 in the vehicle width direction.

Description

Technical Field

[0001] The present invention relates to a lower structure of an electric vehicle.

Background Art

[0002] An electric vehicle has a battery pack disposed on the lower side of a floor panel that constitutes a floor portion of the vehicle, as disclosed in, for example, Patent Document 1. Also, in this example, a drive electric motor is disposed on the front side of the vehicle of the battery pack.

[0003] Further, in order to extend the cruising range of an electric vehicle, the battery pack is required to have a larger capacity. As a result, the battery pack tends to become larger. As the battery pack becomes larger, the proportion of the space occupied by the battery pack in the space on the lower side of the floor portion increases.

[0004] Also, in an electric vehicle, it is necessary to secure a space for disposing a battery pack on the lower side of a floor panel. In the structure of the above example, the floor panel is disposed on the upper side of side members disposed on both sides in the vehicle width direction. The battery pack is disposed on the lower side of the floor panel and between the side members on both sides.

[0005] The side members in the above example are members for ensuring vehicle body rigidity, and for example, strength capable of withstanding an impact load acting on the vehicle body due to a side collision, a front collision, or the like is required. In order to set the dimension of the battery pack in the vehicle width direction as large as possible, the outer portion of the battery pack in the vehicle width direction and the inner portion of the side member in the vehicle width direction are disposed closer to each other.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] The sides of the underside of the vehicle body must have a certain level of strength against impact loads such as side collisions, and these sides must be equipped with a structure that absorbs the impact caused by such impacts. For example, the structure that absorbs the impact load absorbs the impact load by deforming the side of the vehicle body. Therefore, the side of the vehicle body must be provided with a stroke for deformation.

[0008] However, when attempting to provide an impact-absorbing structure on the outer side in the vehicle width direction of a highly rigid side member, the structure in the above example has limited space on the outer side of the side member in the vehicle width direction, making it difficult to secure sufficient stroke for the side of the vehicle body to deform in order to absorb the impact. Therefore, in the structure in the above example, there was room for improvement in effectively absorbing impact loads from side collisions, etc., in the space on the outer side of the battery pack in the vehicle width direction at the lower side of the vehicle body.

[0009] The present invention was made to solve the above problems, and its objective is to provide an understructure for an electric vehicle that can install a battery pack in a limited space below the vehicle floor and protect the battery pack from impact loads. [Means for solving the problem]

[0010] To achieve the above objective, the electric vehicle substructure according to the present invention comprises: a pair of side members arranged on the outer side in the vehicle width direction at the bottom of the vehicle and extending in the vehicle longitudinal direction; a side sill arranged on the outer side in the vehicle width direction of the side members and extending in the vehicle longitudinal direction; and a battery pack arranged between the side members. The electric vehicle substructure comprises a hanger portion provided on the side member to which a trailing arm is connected; and a bracket extending from the hanger portion toward the side sill, wherein the rigidity of the bracket in the vehicle width direction is set lower than the rigidity of the hanger portion in the vehicle width direction. [Effects of the Invention]

[0011] According to the present invention, a battery pack can be installed in the limited space below the vehicle floor and protected from impact loads. [Brief explanation of the drawing]

[0012] [Figure 1] This is a perspective view of the lower structure of the electric vehicle according to the present invention, as seen from above the floor portion of the electric vehicle. [Figure 2] Figure 1 is a perspective view of the left side of the electric vehicle with the side body outer panel attached, seen from below the vehicle. [Figure 3] Figure 1 is a bottom view of the undercarriage of the electric vehicle, as seen from below. [Figure 4] Figure 2 is an enlarged perspective view of the hanger member and side bracket, etc., as seen from the underside of the vehicle. [Figure 5] This is an enlarged bottom view showing the battery pack removed from Figure 3. [Figure 6] This is an enlarged perspective view showing a magnified view of section X in Figure 3. [Figure 7] Figure 3 is a perspective view of section AA as seen from the rear of the vehicle. [Figure 8] Figure 5 is an end view taken along the BB arrow, with the battery pack and battery suspension bracket added for clarity. [Figure 9] Figure 5 is a cross-sectional view taken along the BB arrow, with the battery suspension bracket added for illustration. [Modes for carrying out the invention]

[0013] Hereinafter, one embodiment of the understructure of the electric vehicle according to the present invention will be described with reference to the drawings (Figures 1 to 9). In the figures, the direction of arrow Fr indicates the front in the longitudinal direction of the vehicle. In the description of the embodiment, "front (front end) and rear (rear end)" correspond to the front and rear of the vehicle in the longitudinal direction. Arrows R and L indicate the right and left sides when an occupant looks forward of the vehicle. Arrow U indicates the upward direction in the vertical direction of the vehicle.

[0014] As shown in Figures 2 to 4, the lower structure of the electric vehicle in this embodiment has a battery pack 10 located below the floor. Furthermore, as shown in Figure 3, the lower structure includes a side member 20, a side sill 40, a hanger member 60 (hanger portion), and a side bracket 70 (bracket).

[0015] As shown in Figures 1 and 3, the battery pack 10 is a heavy object located below the floor panel 17 that constitutes the floor of the vehicle. A detailed explanation of the structure of the battery pack 10 will be omitted, but the external shape of the battery pack 10 is roughly rectangular, and it has a top surface 11, left and right side walls 12, a bottom surface 13, a front wall 14, and a rear wall 15 (Figures 3 and 4). The battery pack 10 is suspended from a vehicle body component such as a side member 20, for example, via a battery mount member 30 and a battery suspension bracket 35. The configuration in which the battery pack 10 is attached will be explained later.

[0016] The side member 20 is a highly rigid member that constitutes the vehicle body skeleton and is formed of a metallic material. As shown in FIG. 3, the side members 20 are arranged in a pair on both outer sides in the vehicle width direction at the lower part of the vehicle and extend in the vehicle longitudinal direction. In this example, they are arranged along the side wall portions 12 of the battery pack 10 with a space therebetween on the outer sides in the vehicle width direction of the left and right side wall portions 12 of the battery pack 10. In the vehicle longitudinal direction, the front portion of the side member 20 is arranged on the vehicle front side of the front wall portion 14 of the battery pack 10, and the rear portion of the side member 20 is arranged on the vehicle rear side of the rear wall portion 15 of the battery pack 10.

[0017] As shown in FIGS. 7 to 9, the side member 20 has a U-shaped cross-sectional shape that opens upward in the vehicle. That is, the side member 20 has an inner wall portion 21, an outer wall portion 22, and a bottom surface portion 23, and the bottom surface portion 23 has a substantially rectangular horizontal plane that extends in the vehicle longitudinal direction. The inner wall portion 21 projects upward from the inner end in the vehicle width direction of the bottom surface portion 23 and extends in the vehicle longitudinal direction. An inner flange portion 21a that projects inward in the vehicle width direction is provided at the upper end of the inner wall portion 21. The outer wall portion 22 projects upward from the outer end in the vehicle width direction of the bottom surface portion 23 and extends in the vehicle longitudinal direction. An outer flange portion 22a that projects outward in the vehicle width direction is provided at the upper end of the outer wall portion 22. The inner flange portion 21a and the outer flange portion 22a are joined to the lower surface of the floor panel 17 by spot welding. Further, two reinforcing plates 20a, 20b are joined inside the side member 20.

[0018] In addition, in the present embodiment, a plurality of cross members 25 and 26 extending in the vehicle width direction are provided so as to connect the side members 20 on both sides in the vehicle width direction. The cross members 25 and 26 are highly rigid members that constitute the vehicle body skeleton, similar to the side members 20, and are formed of a metal material. As shown in FIG. 5, the lower structure of the present embodiment has a rear cross member 25 and a center cross member 26. Although detailed description is omitted, the outer portion in the vehicle width direction of the rear cross member 25 is joined to a hanger member 60 described later, and the center cross member 26 is disposed at an interval in front of the rear cross member 25 in the vehicle front direction. Note that the cross members 25 and 26 are not limited to the rear cross member 25 and the center cross member 26.

[0019] Here, a configuration in which the battery pack 10 is suspended from the vehicle body will be described. The battery pack 10 is suspended from the vehicle body such as the side member 20 via a battery mount member 30 and a battery suspension bracket 35. The battery mount member 30 is a member extending in the vehicle front-rear direction, as shown in FIGS. 4 and 5, and is joined to the lower portion of the side member 20. As shown in FIGS. 4, 8, and 9, the battery mount member 30 has an inner wall portion 31, an outer wall portion 32, and a bottom surface portion 33, and has a U-shaped cross section similar to the side member 20. The upper portion of the inner wall portion 31 of the battery mount member 30 is joined to the inner wall portion 21 of the side member 20 by spot welding. Similarly, the upper portion of the outer wall portion 32 of the battery mount member 30 is joined to the outer wall portion 22 of the side member 20 by spot welding.

[0020] As shown in FIG. 5, a flange 31a for joining to the center cross member 26 is provided at an intermediate portion in the vehicle front-rear direction of the inner wall portion 31 of the battery mount member 30. The flange 31a is joined to the lower surface of the center cross member 26 by spot welding.

[0021] The battery suspension bracket 35 is suspended from the bottom surface 33 of the battery mount member 30 via a connecting member 35a and is positioned below the bottom surface 33 of the battery mount member 30. As shown in Figures 2 to 4, the battery suspension bracket 35 has a predetermined widthwise length and extends in the longitudinal direction of the vehicle. The inner end of the battery suspension bracket 35 in the vehicle width direction is connected to the side surface of the battery pack 10, as shown in Figures 7 and 8.

[0022] Next, the side sill 40 of this embodiment will be described. The side sill 40 is located below the door opening 27 provided on the side of the vehicle, extends in the longitudinal direction of the vehicle, and, like the side member 20, constitutes the vehicle body frame. The front part of the side sill 40 may bulge inward and be joined to the inner part of the side member 20 in the vehicle width direction. As shown in Figures 6 to 9, the side sill 40 has a lower inner panel 41, an upper inner panel 45, and an upper outer panel 50. The side sill 40 also has an outer part that is located on the outermost side of the vehicle. In this embodiment, as shown in Figures 2 and 4, the outer part of the side sill 40 is made up of a part of the side body outer panel 28 that constitutes the outermost part of the vehicle. The outer part of the side sill 40 may be arranged to cover the lower inner panel 41 and the upper inner panel 45 from the outside in the vehicle width direction.

[0023] As shown in Figures 1 and 7, the upper outer panel 50 extends horizontally in the longitudinal direction of the vehicle, and the upper surface of the upper outer panel 50 functions as a footrest when occupants get in and out of the door opening 27. In this embodiment, the battery pack 10 is mounted on the lower side of the floor, and the floor is set slightly higher, so the upper outer panel 50 is effective as a footrest. Although not shown, a bead may be provided on the upper surface of the upper outer panel 50 as an anti-slip measure, for example. In this case, the bead may be formed to extend in the vehicle width direction, or it may be formed to extend at a slight incline with respect to the vehicle width direction. A door rail 55 on which a sliding door (not shown) runs is joined to the lower surface of the upper outer panel 50.

[0024] An upper flange portion 51 projecting upward is provided on the inner side of the upper surface of the upper outer panel 50 in the vehicle width direction. The upper flange portion 51 is joined to the outer wall portion 22 of the side member 20 by spot welding. In addition, a rear flange portion 52 projecting upward is provided at the rear end of the upper surface of the upper outer panel 50. For example, as shown in Figures 7 and 9, the rear flange portion 52 is joined to the side panel 16, which is located on the outside of the upper floor panel 18, for example by spot welding. In this example, the cushion portion of the rear seat (not shown) is installed on the upper floor panel 18.

[0025] As shown in Figures 6 to 9, the upper inner panel 45 is a panel that covers the door rail 55 from the inside in the vehicle width direction and from the lower side of the vehicle. The upper inner panel 45 has a bottom surface portion 46, an inner wall portion 47, an upper flange portion 47a, and an outer wall portion 48. The bottom surface portion 46 is positioned below the lower surface of the upper outer panel 50 with a gap between them. The bottom surface portion 46 is approximately horizontal and extends in the longitudinal direction of the vehicle. The bottom surface portion 46 is positioned below the door rail 55 with a gap between them and the door rail 55, covering the door rail 55 from below.

[0026] The inner wall portion 47 extends upward from the inside in the vehicle width direction of the bottom surface portion 46 to the lower surface of the upper outer panel 50. The inner wall portion 47 is positioned at a distance from the inside in the vehicle width direction of the door rail 55, and is positioned to cover the door rail 55 from the inside in the vehicle width direction. The upper flange portion 47a is the portion that protrudes outward in the vehicle width direction from the upper end of the inner wall portion 47 and is joined to the lower surface of the upper outer panel 50 by spot welding. For example, the lower arm provided at the bottom of the sliding door is positioned in the space formed by the upper outer panel 50, the inner wall portion 47 of the upper inner panel 45, and the bottom surface portion 46, and travels on the door rail 55.

[0027] The outer wall portion 48 of the upper inner panel 45 is a wall portion that extends downward from the outer end in the vehicle width direction of the bottom surface portion 46. As shown in Figure 7, a stepped portion 48a is provided in the middle of the outer wall portion 48 in the vehicle vertical direction. The lower side of the stepped portion 48a is positioned further outward in the vehicle width direction compared to the upper side of the stepped portion 48a. By providing the stepped portion 48a, it is possible to improve the rigidity in the vehicle longitudinal direction. The outer wall portion 48 located below the stepped portion 48a is joined to the lower inner panel 41, for example, by spot welding.

[0028] Next, the lower inner panel 41 will be described. As shown in Figures 6 to 9, the lower inner panel 41 is a panel positioned below the upper inner panel 45. The lower inner panel 41 has an outer wall portion 42, an inclined surface portion 43, and an inner wall portion 44. The outer wall portion 42 is a side wall facing outward in the vehicle width direction and extends in the vehicle's longitudinal direction. The upper part of the outer wall portion 42 of the lower inner panel 41 is joined to the lower part of the outer wall portion 48 of the upper inner panel 45 by spot welding on the inside.

[0029] As shown in Figures 6 to 9, the inclined surface portion 43 of the lower inner panel 41 is the part that extends downward from the lower end of the outer wall portion 42 in the vehicle width direction, sloping downward from the vehicle. The inner wall portion 44 is a side wall that extends downward from the inner end of the inclined wall portion in the vehicle width direction. In the vehicle width direction, the inner wall portion 44 of the lower inner panel 41 is located below the door rail 55.

[0030] Next, the hanger member 60 will be described. The hanger member 60 is provided on the side member 20, and a trailing arm is connected to the hanger member 60. In this example, as shown in Figures 6 and 7, the hanger member 60 is a member that extends downward from the lower surface of the side member 20 to the lower part of the vehicle, and is a highly rigid member made of metal. A load is applied to the hanger member 60 via the trailing arm. Therefore, the hanger member 60 has the rigidity to withstand this load. In addition, the battery pack 10 is positioned on the inside of the hanger member 60 in the vehicle width direction. The configuration of the hanger member 60 will be described below.

[0031] The hanger member 60 has an inner wall portion 61, an outer wall portion 62, a front wall portion 63, and a clamping member 64 (clamping portion). The inner wall portion 61 is the portion having a wall surface facing inward in the vehicle width direction and extends downward from the lower part of the inner wall portion 61 of the side member 20 toward the vehicle. The upper part of the inner wall portion 61 of the hanger member 60 is joined to the inner wall portion 21 of the side member 20 by spot welding. The inner wall portion 61 of the hanger member 60 and the side wall portion 12 of the battery pack 10 are spaced apart from each other in the vehicle width direction.

[0032] The outer wall portion 62 is the part having a wall surface facing outward in the vehicle width direction, and extends downward from the lower part of the outer wall portion 22 of the side member 20 toward the vehicle. The upper part of the outer wall portion 62 of the hanger member 60 is joined to the outer wall portion 22 of the side member 20 by spot welding. The side sill 40 and the side bracket 70, which will be described later, are arranged on the outer side of the outer wall portion 62 in the vehicle width direction. Furthermore, a reinforcement 38 is joined to the outer wall portion 62 as shown in Figures 3, 8, and 9. The reinforcement 38 extends in the longitudinal direction of the vehicle, has an L-shaped cross-section, and is joined to the outer wall portion 62 of the hanger member 60 and the lower surface of the bottom surface portion 47 of the upper inner panel 45.

[0033] As shown in Figures 5 and 6, the front wall portion 63 is a wall portion that connects the front end of the outer wall portion 62 and the front end of the inner wall portion 61, and extends inclined toward the rear of the vehicle as it goes downwards towards the vehicle. That is, the front wall portion 63, the inner wall portion 61 and the outer wall portion 62 form a U-shaped closed cross section. The front part of the trailing arm is positioned inside the U-shaped closed cross section and is rotatably connected, for example, to the lower part of the inner wall portion 61 and the lower part of the outer wall portion 62.

[0034] As shown in Figure 6, the clamping member 64 is a portion that is clamped by the inner wall portion 61 and the outer wall portion 62 and extends in the vehicle width direction, and in this embodiment, it is a substantially rectangular plate-shaped member. In this embodiment, the hanger member 60 has a hanger body composed of the front wall portion 63, outer wall portion 62, inner wall portion 61, etc. described above, and a clamping member 64 that is separate from the hanger body. The clamping member 64 has a rectangular main surface portion 65, an inner flange portion 66, an outer flange portion 67, and an upper flange portion 68. The main surface portion 65 is inclined and extends toward the front of the vehicle as it is directed toward the lower part of the vehicle. In addition, the main surface portion 65 is provided with a plurality of width-direction beads 69 that extend in the vehicle width direction. The plurality of width-direction beads 69 are arranged at intervals from each other in the longitudinal direction of the main surface portion 65.

[0035] The upper flange portion 68 is the part that protrudes from the upper end of the main surface portion 65 toward the rear of the vehicle and is preferably joined to the lower surface of the bottom surface portion 23 of the side member 20 by spot welding. The lower end of the main surface portion 65 is located in the middle of the inner wall portion 61 and outer wall portion 62 of the hanger member 60 in the vehicle's vertical direction. In this example, the lower end is located approximately in the center of the inner wall portion 61 and outer wall portion 62 in the vehicle's vertical direction.

[0036] The inner flange portion 66 of the clamping member 64 protrudes toward the rear of the vehicle from the inner end in the vehicle width direction of the main surface portion 65 and extends along the inclination direction of the main surface portion 65. The inner flange portion 66 is joined to the inner surface of the inner wall portion 61 of the hanger member 60 by spot welding. Here, the inner surface is the wall surface facing the space between the inner wall portion 61 and the outer wall portion 62 of the hanger member 60.

[0037] The outer flange portion 67 of the clamping member 64 protrudes rearward from the outer end in the vehicle width direction of the main surface portion 65 and extends along the inclination direction of the main surface portion 65. The outer flange portion 67 is joined to the inner surface of the outer wall portion 62 of the hanger member 60 by spot welding. The outer flange portion 67 of the clamping member 64 is joined to the outer wall portion 62 at a position corresponding to the inner flange portion 73 of the side bracket 70, which will be described later. The positional relationship between the side bracket 70 and the clamping member 64 will be explained later.

[0038] Next, the side bracket 70 will be described. As shown in Figures 3 to 6, the side bracket 70 is a panel made of a metal material and extends from the hanger member 60 toward the side sill 40. The side bracket 70 is positioned in the longitudinal direction of the vehicle to correspond to the rear of the battery pack 10. In this example, as shown in Figures 3 and 4, the side bracket 70 is positioned on the outside in the vehicle width direction of the rear wall portion 15 of the battery pack 10.

[0039] In this embodiment, the rigidity of the side bracket 70 in the vehicle width direction is set lower than that of the hanger member 60 in the vehicle width direction. Since the side bracket 70 is a single panel formed from a metal material, it has lower rigidity than the hanger member 60. For example, the thickness of the side bracket 70 may be formed to be thinner than the thickness of the inner wall portion 61, the outer wall portion 62, and the front wall portion 63 of the hanger member 60.

[0040] As described above, the battery pack 10 is positioned on the vehicle side of the hanger member 60. For example, when subjected to an impact load such as a side collision, it is necessary to prevent the intrusion of the impacting object into the battery pack 10. In this embodiment, the high-rigidity hanger member 60 and side member 20 are positioned on the outside in the vehicle width direction of the battery pack 10. Therefore, the impact load can be received by the highly rigid members.

[0041] For example, impact loads resulting from side collisions are first applied to the side sill 40. If the impact load applied to the side sill 40 causes it to deform, for example, inward in the vehicle width direction, then that load is applied to the side bracket 70. In addition, a portion of the impact energy from the impact load is converted into deformation energy as the side sill 40 deforms.

[0042] When an impact load is applied to the side bracket 70, the side bracket 70 deforms so as to collapse in the vehicle width direction. The impact energy applied to the side bracket 70 is converted into deformation energy as the side bracket 70 deforms and collapses. As a result, a portion of the impact load is absorbed by the side bracket 70.

[0043] The side sill 40 and side bracket 70 absorb the impact load, thereby reducing the impact energy of the impact load input to the hanger member 60. Here, since the hanger member 60 has higher rigidity than the side bracket 70, it is able to withstand the impact load with reduced impact energy.

[0044] As shown in Figure 6, the hanger member 60 is joined to the side member 20, so that the side member 20 and the hanger member 60 can withstand impact loads. Since the side member 20 extends in the longitudinal direction of the vehicle, the load applied to the hanger member 60 is transmitted to the side member 20, and can be effectively transmitted to the front and rear of the vehicle, thereby effectively distributing the load. Therefore, according to the above configuration of this embodiment, it is possible to reduce the impact load transmitted to the rear of the battery pack 10, and the battery pack 10 can be protected from impact loads.

[0045] Furthermore, according to this embodiment, by providing the side bracket 70, impact loads can be effectively absorbed between the side sill 40 and the side member 20, so the side member 20 can be positioned outward in the vehicle width direction, and as a result, a larger battery pack 10 can be placed in the limited space below the floor.

[0046] Here, the details of the side bracket 70 will be described. As shown in Figures 7 and 9, the side bracket 70 of this embodiment has a main surface portion 71 and an extension portion 72, and further has flanges formed on the outer circumference of the main surface portion 71 and the extension portion 72, which function as reinforcing ribs. The flanges include an inner flange portion 73, an outer flange portion 74, and an upper flange portion 75.

[0047] The main surface portion 71 is the part that extends in the vehicle width direction and is positioned between the outer wall portion 62 of the hanger member 60 and the inner wall portion 47 of the upper inner panel 45 of the side sill 40. The main surface portion 71 is inclined towards the rear of the vehicle as it extends downwards towards the vehicle. The direction of inclination of the main surface portion 71 corresponds to the direction of inclination of the clamping member 64 of the hanger member 60.

[0048] The extension portion 72 extends downward from the lower part of the main surface portion 71 and outward in the vehicle width direction. The lower end of the extension portion 72 is positioned below the lower end of the side sill 40 (the lower end of the inner wall portion 44 of the lower inner panel 41). The extension portion 72 is positioned between the outer wall portion 62 of the hanger member 60 and the inner wall portion 44 of the lower inner panel 41 of the side sill 40, and extends in the vehicle width direction. In other words, the length of the extension portion 72 in the vehicle width direction is set to be longer than the length of the main surface portion 71 in the vehicle width direction.

[0049] Furthermore, the inclination angle of the main surface portion 71 with respect to the vertical direction (the angle formed downward by the main surface portion 71 and the vertical direction) is set to be greater than the inclination angle of the extension portion 72. Note that the extension portion 72 may extend along the vertical direction without inclination.

[0050] As shown in Figure 6, the inner flange portion 73 of the side bracket 70 protrudes toward the rear of the vehicle from the inner end in the vehicle width direction of the main surface portion 71 and the extension portion 72, and extends along the inclination direction of the main surface portion 71 and the extension portion 72. The inner flange portion 73 is joined to the outer wall portion 62 of the hanger member 60 by spot welding. In this embodiment, the inner flange portion 73 located on the main surface portion 71, the outer wall portion 62 of the hanger member 60, and the outer flange portion 67 of the clamping member 64 are joined in a triple-layered manner.

[0051] The outer flange portion 74 of the side bracket 70 protrudes rearward from the outer ends in the vehicle width direction of the main surface portion 71 and the extension portion 72, and extends along the inclination direction of the main surface portion 71 and the extension portion 72. The outer flange portion 74 located above the main surface portion 71 is joined to the outer wall portion 62 of the hanger member 60 by spot welding, and the outer flange portion 74 located on the extension portion 72 is joined to the inner wall portion 44 of the lower inner panel 41 by spot welding. The outer flange portion 74 located below the main surface portion 71 is inclined outward in the vehicle width direction as it extends downward towards the vehicle, and is positioned with a gap inward in the vehicle width direction from the outer wall portion 48 of the upper inner panel 45.

[0052] The upper flange portion 75 protrudes forward from the upper end of the main surface portion 71 and extends along the vehicle width direction. The upper flange portion 75 is joined to the lower surface of the upper outer panel 50 by spot welding.

[0053] In this embodiment, the outer flange portion 74 of the side bracket 70 is joined to the inside of the side sill 40, and the side bracket 70 has an extension portion 72, which expands the range in which impact energy due to impact loads in the vehicle width direction can be absorbed downwards of the vehicle. Therefore, the amount of impact energy absorbed by the side bracket 70 can be further improved.

[0054] Furthermore, as shown in Figures 6 and 9, the side bracket 70 is joined to the lower surface of the upper outer panel 50 of the side sill 40, so it is also possible to transmit the load from the extension portion 72 toward the floor portion of the vehicle. Since the side bracket 70 is joined to the hanger member 60, the rigidity in the vertical direction of the vehicle can be set to be high. Therefore, the side bracket 70 also functions stably as a contact point for jacking up.

[0055] Furthermore, the side bracket 70 of this embodiment is inclined as described above, and the inclination direction of the main surface portion 71 is inclined along the inclination direction of the clamping member 64 of the hanger member 60. In addition, since the clamping member 64 and the side bracket 70 are arranged side by side in the vehicle width direction via the outer wall portion 62 of the hanger member 60, it is possible to effectively receive the impact load transmitted from the side bracket 70.

[0056] As described above, when the side bracket 70 collapses, a portion of the impact energy is absorbed by the side bracket 70. The impact energy that the side bracket 70 could not absorb can be received by the hanger member 60, which includes a clamping member 64 having high rigidity. Furthermore, since the clamping member 64 extends along the inclination direction described above, it is also possible to transmit the load received by the clamping member 64 upwards.

[0057] Furthermore, in this embodiment, a reinforcing portion is provided in the middle of the side bracket 70 in the vehicle width direction, as shown in Figures 6 and 9, extending from the top to the bottom of the side bracket 70. In this example, the reinforcing portion consists of two vertical beads 76 that extend from the main surface portion 71 to the lower end of the extension portion 72, along the inclination direction of the main surface portion 71 and the extension portion 72. Also, in this embodiment, the rigidity of the clamping member 64 in the vehicle width direction is set higher than the rigidity of the side bracket 70 in the vehicle width direction.

[0058] By providing the vertical bead 76, the rigidity of the side bracket 70 in the vehicle's vertical direction is improved. Therefore, it can be effectively used as a jack-up as described above. Furthermore, the outer end of the vertical bead 76 in the vehicle width direction forms a curved or bent portion (ridge) relative to the upper surface of the main surface portion 71, thus creating a portion with reduced rigidity in the vehicle width direction. As a result, a portion that is more susceptible to crushing under load in the vehicle width direction is formed, improving the shock absorption effect.

[0059] Furthermore, in this embodiment, reinforcing ribs are provided on the outer circumference of the side bracket 70, and the outer flange portion 74, the inner flange portion 73, and the upper flange portion 75 are provided as part of the reinforcing ribs, so that the side bracket 70 can secure a predetermined rigidity. In addition, load is more easily transmitted to the outer flange portion 74, etc., making it easier for the side bracket 70 to absorb impact loads.

[0060] The description of this embodiment is illustrative for explaining the present invention and does not limit the invention as described in the claims. Furthermore, the configuration of each part of the present invention is not limited to the above embodiment, and various modifications are possible within the technical scope described in the claims.

[0061] For example, in this embodiment, the outer portion of the side bracket 70 in the vehicle width direction is joined to the side sill 40, but this is not limited to this. For example, the outer flange portion 74 of the side bracket 70 may be arranged on the side sill 40 with a gap in the vehicle width direction. In this case, when subjected to an impact load such as a side collision, the side sill 40 deforms toward the inside of the vehicle, and then the deformed side sill 40 presses against the side bracket 70, causing the side bracket 70 to deform and absorb the impact load.

[0062] In this embodiment, the upper outer panel 50 constituting the side sill 40 functions as a footrest when an occupant gets in and out of the door opening 27, as described above. Therefore, for example, the structure of the side sill 40 in this embodiment is effective for vehicles with a high floor. For example, in vehicles having a so-called cab-over structure in which the front seats (driver's seat and passenger seat) are located above the electric motor, the structure of the side sill 40 in this embodiment is effective as a countermeasure against side collisions. Furthermore, even in vehicles where the electric motor is located below the front seats, for example, a space R (Figure 1) is provided below the front seats and above the front of the battery pack 10, and any device can be placed there, the structure of the side sill 40 in this embodiment is effective as a countermeasure against side collisions. [Explanation of Symbols]

[0063] 10 Battery Packs 11 Top part 12 Side wall section 13 Bottom part 14 Front wall 15 Rear wall 16 Side Panels 17 Floor Panel 18 Rear floor panel 20 Side Members 20a Reinforcement plate 20b Reinforcement Plate 21 Inner wall section 21a Inner flange portion 22 Exterior wall 22a Outer flange portion 23 Bottom part 25 Rear cross member 26 Center Cross Member 27 Door opening 28 Side Body Outer Panel 30 Battery Mount Members 31 Inner wall section 31a Flange 32 Exterior wall 33 Bottom part 35 Battery suspension bracket 38 Reinforcement 40 Side Sill 41 Lower Inner Panel 42 Exterior wall 43 Slope section 44 Inner wall section 45 Upper Inner Panel 46 Bottom part 47 Inner wall section 47a Upper flange portion 48 Exterior wall 48a Stepped section 50 Upper Outer Panels 51 Upper flange section 52 Rear flange section 55 Door rails 60 Hanger component (hanger part) 61 Inner wall section 62 Exterior wall 63 Front wall 64 Clamping member (clamping part) 65 Main surface 66 Inner flange section 67 Outer flange section 68 Upper flange section 69 Width direction bead 70 Side Bracket (Bracket) 71 Main surface section 72 Extension part 73 Inner flange section 74 Outer flange section 75 Upper flange section 76. Vertical bead (reinforcement section) R space part

Claims

1. An understructure for an electric vehicle comprising: a pair of side members arranged on the outer side in the width direction of the vehicle's underside and extending in the longitudinal direction of the vehicle; a side sill arranged on the outer side in the width direction of the side members and extending in the longitudinal direction of the vehicle; and a battery pack arranged between the side members, A hanger portion provided on the side member to which the trailing arm is connected, A bracket extending from the hanger portion toward the side sill, It has, An understructure for an electric vehicle, characterized in that the rigidity of the bracket in the vehicle width direction is lower than the rigidity of the hanger portion in the vehicle width direction.

2. The vehicle understructure according to claim 1, characterized in that the bracket extends in the vehicle width direction, and the outer portion of the bracket in the vehicle width direction is joined to the side sill.

3. The lower structure of an electric vehicle according to claim 1 or claim 2, characterized in that the hanger portion has an inner wall portion facing inward in the vehicle width direction, an outer wall portion facing outward in the vehicle width direction, and a clamping portion that is sandwiched by the inner wall portion and the outer wall portion and extends in the vehicle width direction.

4. The bracket is inclined forward or backward as it extends downward towards the vehicle. The lower structure of an electric vehicle according to claim 3, characterized in that the clamping portion is inclined along the inclination direction of the bracket.

5. A reinforcing portion is provided in the middle of the bracket in the vehicle width direction, extending from the top to the bottom of the bracket. The lower structure of an electric vehicle according to claim 3, characterized in that the rigidity of the clamping portion in the vehicle width direction is set higher than the rigidity of the bracket in the vehicle width direction.

6. The lower structure of an electric vehicle according to claim 1 or claim 2, characterized in that a flange protruding forward or in the direction of the vehicle is provided on the inner side of the bracket in the vehicle width direction, and the flange is joined to the outer wall portion of the hanger portion.

7. The lower structure of an electric vehicle according to claim 1 or claim 2, characterized in that the bracket is provided with an extension portion that extends downward in the vehicle's vertical direction from the side sill.

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