Vehicle understructure

Abstract

To provide a vehicle understructure capable of minimizing an impact load, which is imposed on a battery, at a time of a vehicle collision.SOLUTION: An EA unit 42 disposed to be superposed on a floor cross member 34 and a battery pack 20 in a vehicle side view is incorporated in a rocker 16. A part of the EA unit 42 serves as a high rigidity part 48. Since the load transmission efficiency for an impact load F is enhanced by the high rigidity part 48, the impact load F can be guided in a predetermined direction toward inside in a vehicle width direction. In other words, since the inputted impact load F is guided toward the floor cross member 34, the impact load F to be imposed on the battery pack 20 can be minimized.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a vehicle undercarriage. [Background technology]

[0002] The following Patent Document 1 discloses a technology relating to a vehicle underbody structure that can mount a battery pack. This prior art discloses a structure in which a shock absorbing part is provided in a locker at a position that overlaps with the battery pack when viewed from the side of the vehicle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-006303 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above prior art, at least a portion of the side impact load (impact load) during a side impact of the vehicle (hereinafter referred to as "vehicle side impact") is absorbed by the impact absorbing section. However, since a battery pack (hereinafter referred to as "battery") is provided on the inside of the impact absorbing section in the vehicle width direction, the input load to the battery may be large.

[0005] SUMMARY OF THE PRESENT INVETION The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a vehicle underbody structure capable of reducing the impact load input to a battery in the event of a side collision of the vehicle. [Means for solving the problem]

[0006] The vehicle undercarriage structure of the invention described in claim 1 comprises a pair of rockers extending in the fore-and-aft direction of the vehicle on both outer sides in the vehicle width direction, a cross member extending in the vehicle width direction above the vehicle of a battery connected to the pair of rockers and between the pair of rockers, with both ends in the extension direction connected to the pair of rockers, and an impact absorbing section provided within the pair of rockers, arranged so as to overlap the cross member and the battery in a side view of the vehicle, and provided with a first guiding section that guides an impact load input from the outside in the vehicle width direction toward the cross member.

[0007] The vehicle underbody structure according to the invention recited in claim 1 includes a pair of rockers, a cross member, and an impact absorbing part. The pair of rockers extend in the front-rear direction of the vehicle on both outer sides in the vehicle width direction. The cross member extends in the vehicle width direction between the pair of rockers and above the battery connected to the pair of rockers, and both ends of the cross member in the extension direction are connected to the pair of rockers.

[0008] On the other hand, the impact absorbing parts are provided in each of the pair of rockers and are arranged so as to overlap with the cross member and the battery in a side view of the vehicle. Therefore, the impact load input from the outside in the vehicle width direction is absorbed by the impact absorbing parts. Here, in the present invention, the impact absorbing parts are provided with a first guiding part, and the first guiding part makes it possible to guide (transmit) the impact load to the cross member side. In other words, in the present invention, it is possible to control the transmission direction of the load.

[0009] In the present invention, the impact load input to the battery is relatively reduced by guiding the impact load to the cross member provided on the vehicle upper side of the battery by the first guiding portion. Note that "guiding" here means that the proportion of the load transmitted to the battery is greater than that of other portions.

[0010] The vehicle underbody structure of the invention described in claim 2 is the vehicle underbody structure of the invention described in claim 1, wherein the impact absorbing portion is configured to include a plurality of energy absorbing portions arranged along the vehicle vertical direction and vehicle width direction and capable of absorbing impact energy by plastic deformation, and the first guiding portion is configured by a portion of the energy absorbing portions.

[0011] In the vehicle underbody structure according to the invention described in claim 2, the impact absorbing portion includes a plurality of energy absorbing portions arranged along the vehicle vertical direction and the vehicle width direction, and impact energy is absorbed by plastic deformation of the energy absorbing portions. Here, the first guide portion is formed by some of the plurality of energy absorbing portions.

[0012] In other words, in the present invention, by making some of the same energy absorption parts as first inducing parts having higher rigidity than the other energy absorption parts, it is possible to transmit the impact load, and thereby it is possible to more effectively control the load transmission direction of the impact load.

[0013] The vehicle underbody structure of the invention recited in claim 3 is the vehicle underbody structure of the invention recited in claim 2, wherein the energy absorption portion has a closed cross-sectional shape when cut along the vehicle width direction.

[0014] In the vehicle underbody structure of the invention described in claim 3, the energy absorbing portion has a closed cross-sectional shape when cut along the vehicle width direction, and compared to a case in which the cross-sectional shape is an open cross-sectional shape, the impact absorbing portion itself can obtain higher rigidity, and the amount of impact energy absorbed by plastic deformation can be increased accordingly.

[0015] The vehicle underbody structure according to the invention recited in claim 4 is the vehicle underbody structure according to the invention recited in claim 2, wherein the energy absorbing portion constituting the first guide portion has a higher rigidity than other energy absorbing portions.

[0016] In the vehicle underbody structure according to the invention recited in claim 4, the energy absorbing portion constituting the first guide portion has higher rigidity than the other energy absorbing portions, thereby making it possible to control the load transmission direction of the impact load.

[0017] The vehicle underbody structure of the invention described in claim 5 is the vehicle underbody structure of the invention described in claim 1, wherein the battery is fastened to the rocker via a fastening portion, and the impact absorbing portion is configured to include a second guiding portion that guides the impact load toward the fastening portion.

[0018] In the vehicle underbody structure according to the invention recited in claim 5, the battery is fastened (connected) to the rocker via a fastening portion. The shock absorbing portion includes a second guiding portion, and the second guiding portion can guide an impact load input from the outside in the vehicle width direction to the fastening portion.

[0019] Since the fastening portion of the battery is made to have high rigidity, the impact load is guided to the fastening portion by the second guide portion, and thus the present invention makes it possible to reduce the impact load input to the battery. In addition, the impact load is guided to both the cross member and the fastening portion, so that the rocker as a whole can absorb the impact in a well-balanced manner, and as a result, it becomes possible to improve the strength of the rocker itself.

[0020] The vehicle underbody structure of the invention described in claim 6 is the vehicle underbody structure of the invention described in claim 5, in which the energy absorption portion constituting the second guiding portion has higher rigidity than other energy absorbing portions other than the first guiding portion.

[0021] In the vehicle underbody structure of the invention described in claim 6, the energy absorbing portion constituting the second guiding portion has higher rigidity than other energy absorbing portions other than the first guiding portion, making it possible to control the load transmission direction of the impact load.

[0022] The vehicle underbody structure according to the invention recited in claim 7 is the vehicle underbody structure according to the invention recited in claim 2, wherein the first guiding portion is arranged such that, among the energy absorption portions constituting the first guiding portion, the energy absorption portion provided on the inner side in the vehicle width direction is positioned further up the vehicle than the energy absorption portion provided on the outer side in the vehicle width direction.

[0023] In the vehicle underbody structure of the invention described in claim 7, the first guiding portion is arranged such that, among the energy absorption portions constituting the first guiding portion, the energy absorption portion provided on the inner side in the vehicle width direction is positioned higher on the vehicle than the energy absorption portion provided on the outer side in the vehicle width direction, thereby making it possible to guide the impact load input from the outer side in the vehicle width direction of the battery (the lower side of the rocker) to the upper side of the battery (the cross member side).

[0024] The vehicle underbody structure of the invention described in claim 8 is the vehicle underbody structure of the invention described in claim 2, wherein, in the first guiding portion, at least a portion of the energy absorbing portions adjacent to each other in the vehicle width direction overlap in the vehicle up-down direction.

[0025] In the vehicle underbody structure according to the invention recited in claim 8, in the first guide portion, at least a portion of the energy absorbing portions adjacent in the vehicle width direction overlap in the vehicle up-down direction, thereby increasing the load transmission efficiency of the impact load input along the vehicle width direction in the overlapping range. Therefore, according to the present invention, it is possible to transmit the impact load more effectively.

[0026] The vehicle underbody structure of the invention described in claim 9 is the vehicle underbody structure of the invention described in claim 1, wherein the first guiding portion includes an inclined portion that inclines toward the upper side of the vehicle as it moves inward in the vehicle width direction.

[0027] In the vehicle underbody structure according to the invention recited in claim 9, the first guiding portion includes an inclined portion that inclines toward the upper side of the vehicle as it approaches the inside in the vehicle width direction, and it is possible to transmit the impact load toward the upper side of the vehicle (toward the cross member) via the inclined portion. In this way, by providing the inclined portion, the degree of freedom in controlling the load transmission direction (degree of design freedom) is increased.

[0028] The vehicle underbody structure of the invention recited in claim 10 is the vehicle underbody structure of the invention recited in claim 9, wherein the outer end portion of the inclined portion in the vehicle width direction is located outside the fastening portion in the vehicle width direction, and the inner end portion of the inclined portion in the vehicle width direction is located above the vehicle than the fastening portion.

[0029] In the vehicle undercarriage structure of the invention described in claim 10, the outer end of the inclined portion is located outside the fastening portion between the battery and the rocker in the vehicle width direction, and the inner end of the inclined portion is located above the vehicle in the fastening portion, thereby making it possible to prevent impact loads from being transmitted beyond the fastening portion to the inside in the vehicle width direction. Effect of the Invention

[0030] As described above, the vehicle underbody structure according to the present invention can reduce the impact load input to the battery in the event of a side collision of the vehicle. [Brief description of the drawings]

[0031] [Figure 1] 1 is an enlarged cross-sectional view of a main part of a vehicle to which the vehicle underbody structure relating to the first embodiment is applied; FIG. [Diagram 2] FIG. 2 is an enlarged cross-sectional view of a main part showing a first modified example of a vehicle to which the vehicle underbody structure relating to the first embodiment is applied. [Diagram 3] FIG. 11 is an enlarged cross-sectional view of a main part of a vehicle to which a vehicle underbody structure relating to a second embodiment is applied. [Figure 4]FIG. 11 is an enlarged cross-sectional view of a main part of a vehicle to which the vehicle underbody structure relating to the third embodiment is applied. [Diagram 5] FIG. 11 is an enlarged cross-sectional view of a main part showing a first modified example of a vehicle to which the vehicle underbody structure relating to the third embodiment is applied. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] The vehicle underbody structure according to the embodiment of the present invention will be described with reference to the drawings. The arrows UP and RH shown in each drawing indicate the upward and rightward directions of the vehicle to which the vehicle underbody structure according to the present embodiment is applied, respectively. Hereinafter, when the directions of front-rear, left-right, and up-down are simply used for the description, they indicate front-rear in the vehicle front-rear direction, left-right in the vehicle left-right direction (vehicle width direction), and up-down in the vehicle up-down direction, unless otherwise specified. In addition, in each drawing, some members and some symbols may be omitted in order to make the drawings easier to see.

[0033] First Embodiment

[0034] (Vehicle underbody structure configuration) As shown in FIG. 1, a vehicle (vehicle body) 12 to which a vehicle underbody structure 10 according to a first embodiment of the present invention is applied includes a pair of left and right rockers 16 that form a vehicle frame and extend along the front-rear direction of the vehicle at the lower ends of both ends in the vehicle width direction of a passenger compartment 14. Although not shown, a front cross member (not shown) is provided along the vehicle width direction at the front end of the pair of left and right rockers 16, and a rear cross member (not shown) is provided along the vehicle width direction at the rear end of the pair of left and right rockers 16. In addition, the vehicle 12 according to this embodiment is an electric vehicle (BEV) that runs using the driving force of an electric motor (not shown), and a battery pack (battery) 20 that houses a plurality of battery cells 18 that supply driving power to the electric motor is provided under the vehicle 12. The vehicle 10 may be a plug-in hybrid vehicle (PHEV), a fuel cell vehicle (FCEV), or the like.

[0035] Here, the configuration of the vehicle underbody structure according to this embodiment will be described. 1, a vehicle underbody structure 10 according to this embodiment includes a battery pack 20. The battery pack 20 is made of a light metal such as an aluminum alloy, and includes a box-shaped battery case 22 that is rectangular in plan view with the vehicle front-rear direction as the longitudinal direction and that is open at the top. Note that the battery case 22 may be made of a resin material other than metal, such as carbon fiber reinforced plastic (CFRP) or glass fiber reinforced plastic (GFRP).

[0036] The battery case 22 is closed by a cover 24 having a rectangular plate shape in a plan view with the battery cells 18 housed therein. The cover 24 is made of a light metal such as an aluminum alloy, has a plate shape with its thickness direction aligned in the vertical direction of the vehicle, and is integrated with the battery case 22 by welding or the like.

[0037] For example, the battery case 22 includes a bottom wall 26 and a side wall 28 standing upright from the outer edge of the bottom wall 26. For example, a bracket 29 is integrally provided on the side wall 28, and the bracket 29 is fastened to the lower wall portion 16A of the rocker 16 via a fastening portion 32 such as a bolt 30. This allows the battery case 22 to be supported on the rocker 16. Meanwhile, the cover 24 forms a floor that constitutes the floor portion of the passenger compartment 14, and a floor cross member (cross member) 34 is disposed on the cover 24 along the vehicle width direction so as to span between a pair of left and right rockers 16. Although not shown, the bottom wall 26 may extend outward in the vehicle width direction beyond the side wall 28, and the extended portion may serve as the bracket to fasten the lower wall portion 16A of the rocker 16.

[0038] In this embodiment, the rocker 16 is configured to include an outer portion 36 and an inner portion 38, and the outer portion 36 and the inner portion 38 form a closed cross-sectional portion 40. An EA portion (shock absorbing portion) 42 is disposed (placed) within this closed cross-sectional portion 40. The closed cross-sectional portion 40 has a substantially hexagonal cross-sectional shape when cut along the vehicle width direction and the vehicle vertical direction, for example, and is formed so that the dimension in the vehicle vertical direction is longer than the dimension in the vehicle width direction.

[0039] The cross-sectional shape of the closed cross-sectional portion 40 is not particularly limited. In addition, while the rocker 16 is shown in Fig. 1 with the outer portion 36 and the inner portion 38 integrally formed, it goes without saying that the outer portion 36 and the inner portion 38 may be formed of separate members and integrated by joining them together. Furthermore, the EA portion 42 may be connected to the rocker 16 via a connecting portion (not shown), or may be formed integrally with the rocker 16 by extrusion molding or the like.

[0040] Here, in this embodiment, the EA section 42 is configured by a plurality of energy absorbing sections 44, each having a substantially rectangular closed cross-sectional shape when cut along the vehicle width direction and the vehicle up-down direction. In this embodiment, the energy absorbing sections 44 are arranged in a 3×3 grid pattern along the vehicle up-down direction and the vehicle width direction, for example. However, the central portion of the energy absorbing section 44 in the vehicle width direction is shaped so that four of them are provided in the vehicle up-down direction while protruding downward of the vehicle.

[0041] In this embodiment, the plate thickness of the energy absorbing portion 44 is partially changed in the EA portion 42. Specifically, in this embodiment, the energy absorbing portion 44 is configured to include an energy absorbing portion (another energy absorbing portion) 46 shown by hatching and an energy absorbing portion (first guiding portion, second guiding portion) 48 shown by cross-hatching.

[0042] The energy absorption part (hereinafter referred to as the "high-rigidity part") 48 is formed to have a greater plate thickness than the energy absorption part 46, and has a higher rigidity than the energy absorption part 46. Note that at the boundary between the energy absorption part 46 and the energy absorption part 48, a solid line is drawn on the drawing for clarity.

[0043] The high-rigidity part (first guiding part, second guiding part) 48A is disposed on the outer side and lower part in the vehicle width direction in the EA part 42. The high-rigidity part (first guiding part) 48B is disposed at the center in the vehicle width direction in the EA part 42 and on the upper side of the high-rigidity part 48A, and is disposed at a position overlapping with the floor cross member 34 in a side view of the vehicle.

[0044] Also, the high-rigidity part (second guiding part) 48C is disposed at the center in the vehicle width direction in the EA part 42 and on the lower side of the high-rigidity part 48A, and is disposed at a position overlapping with the fastening part 32 in a side view of the vehicle. Further, the high-rigidity part (first guiding part) 48D is disposed on the inner side in the vehicle width direction in the EA part 42 and on the upper side of the high-rigidity part 48A, and is disposed at a position overlapping with the floor cross member 34 in a side view of the vehicle.

[0045] And the high-rigidity parts 48A and 48C are disposed at positions overlapping with the battery case 22 in a side view of the vehicle, and the upper wall part 48D1 of the high-rigidity part 48D and the upper wall part 34A of the floor cross member 34 are disposed at positions overlapping (substantially flush) in a side view of the vehicle. Note that the positions of the upper wall part 48D1 of the high-rigidity part 48D and the upper wall part 34A of the floor cross member 34 in the height direction do not necessarily have to be substantially flush, and the upper wall part 48D1 of the high-rigidity part 48D may be disposed more on the upper side than the upper wall part 34A of the floor cross member 34.

[0046] In the present embodiment, in the EA section 42, starting from the high rigidity section 48A, high rigidity sections 48B, 48D having higher rigidity than the energy absorbing section 46 are formed toward the upper side as they move inward in the vehicle width direction. For this reason, in the event of a side collision of the vehicle 12, the impact load (side collision load) F input to the rocker 16 is absorbed by the plastic deformation of the EA section 42, and is transmitted to the floor cross member 34 side via the high rigidity section 48A, the high rigidity section 48B, and the high rigidity section 48D.

[0047] Furthermore, in this embodiment, a high rigidity portion 48C having higher rigidity than the energy absorbing portion 46 is formed downwardly and inwardly in the vehicle width direction starting from the high rigidity portion 48A. Therefore, in the event of a side collision of the vehicle 12, the impact load F input to the rocker 16 is transmitted to the fastening portion 32 side via the high rigidity portion 48A and the high rigidity portion 48C.

[0048] In other words, in this embodiment, the impact load F is transmitted to the floor cross member 34 side via high rigidity portion 48A, high rigidity portion 48B, and high rigidity portion 48D, and can also be transmitted to the fastening portion 32 side via high rigidity portion 48C.

[0049] In the present embodiment, in the EA section 42, the plate thickness of the high-rigidity section 48 is made thicker than that of the energy absorbing section 46, so that the high-rigidity section 48 has a higher rigidity than the energy absorbing section 46. However, it is sufficient that the rigidity of the high-rigidity section 48 is higher than that of the energy absorbing section 46, and the present invention is not limited to this.

[0050] For example, the high rigidity portion 48 may be integrated with the energy absorbing portion 46 by using a material having a higher rigidity than the energy absorbing portion 46, or the energy absorbing portion 46 may be provided with a reinforcing portion such as a diagonal brace to change the shape to a triangular or hexagonal shape. Furthermore, a reinforcing member may be used in the energy absorbing portion 46. The shape of the energy absorbing portion 46 itself is not limited to a substantially rectangular shape, and may be a triangular or hexagonal shape. This embodiment is similar to other embodiments described later.

[0051] (Action and effect of vehicle underbody structure) Next, the operation and effects of the vehicle underbody structure according to this embodiment will be described.

[0052] 1, in this embodiment, the vehicle underbody structure 10 is provided with a pair of left and right rockers 16, a floor cross member 34, and an EA section 42. The pair of left and right rockers 16 each extend in the front-rear direction of the vehicle on both outer sides in the vehicle width direction, and the floor cross member 34 is disposed between the pair of rockers 16, with both ends of the floor cross member 34 connected to the pair of left and right rockers 16, respectively.

[0053] The EA sections 42 are provided in the pair of left and right rockers 16, respectively, and are disposed so as to overlap the floor cross member 34 and the battery pack 20 in a side view of the vehicle. Therefore, the impact load F input from the outside in the vehicle width direction is reduced by the EA sections 42.

[0054] Here, in this embodiment, a high rigidity section 48 is provided in a part of the EA section 42, the high rigidity section 48 including a first guiding section that guides the impact load F input from the outside in the vehicle width direction toward the floor cross member 34 side and a second guiding section that guides the impact load F toward the fastening section 32 side. By increasing the load transmission efficiency of the impact load F by the high rigidity section 48, the impact load F can be guided in a predetermined direction toward the inside in the vehicle width direction. In other words, in this embodiment, it is possible to control the transmission direction of the load.

[0055] More specifically, in this embodiment, the EA section 42 includes a plurality of energy absorbing sections 44 arranged along the vehicle up-down direction and the vehicle width direction. The high rigidity section 48 constituting a part of the energy absorbing section 44 is formed to have a plate thickness greater than that of the other energy absorbing sections 46, and has a rigidity greater than that of the energy absorbing sections 46.

[0056] In this manner, in this embodiment, by making some of the energy absorbing parts 44 (high rigidity parts 48) have higher rigidity as so-called guide parts than the other energy absorbing parts 46, it becomes possible to transmit the impact load F and control the load transmission direction of the impact load F. This makes it possible to protect the battery pack 20 in this embodiment.

[0057] In this embodiment, the rigidity of the induction section is increased by making the plate thickness thicker than that of the other energy absorption sections 46. This makes it possible to reduce the number of work steps and lower costs, for example, compared to the case where a highly rigid member is integrated with the EA section 42.

[0058] In addition, in this embodiment, the energy absorption portion 44 has a closed cross-sectional shape when cut along the vehicle width direction, and the EA portion 42 itself can obtain higher rigidity than when the cross-sectional shape is an open cross-sectional shape, and the amount of impact energy absorbed by plastic deformation can be increased accordingly.

[0059] Furthermore, in this embodiment, the high rigidity portion 48 is configured to include high rigidity portions 48A, 48B, 48D as first guiding portions, and the high rigidity portion 48 is capable of guiding the impact load F input from the outside in the vehicle width direction to the floor cross member 34. In this manner, the high rigidity portions 48A, 48B, 48D control the load transmission direction to the floor cross member 34, thereby making it possible to guide the input impact load F to the upper side of the rocker 16.

[0060] Furthermore, in this embodiment, the impact load F is guided by the first guiding portion toward the floor cross member 34 provided on the vehicle upper side of the battery pack 20, so that the impact load input to the battery pack 20 is relatively reduced, thereby making it possible to protect the battery pack 20.

[0061] In this embodiment, the battery pack 20 is fastened to the locker 16 via a fastening portion 32. The high rigidity portion 48 is configured to include high rigidity portions 48A, 48C as second guiding portions, and the fastening portion 32 has high rigidity, so that the impact load F input from the outside in the vehicle width direction can be guided to the fastening portion 32 side by the high rigidity portions 48A, 48C.

[0062] Therefore, in this embodiment, the impact load F is guided toward the floor cross member 34 by the high rigidity portions 48A, 48B, 48D, and is also guided toward the high rigidity fastening portion 32 by the high rigidity portions 48A, 48C. That is, in this embodiment, the impact load F is transmitted toward the upper and lower sides of the rocker 16, so that the rocker 16 as a whole can absorb impact energy in a balanced manner, and as a result, the strength of the rocker 16 itself can be improved.

[0063] Furthermore, in this embodiment, the upper wall portion 48D1 of the high rigidity portion 48D and the upper wall portion 34A of the floor cross member 34 are disposed in a position where they overlap in a side view of the vehicle, making it possible to reliably transmit the impact load F guided toward the high rigidity portion 48C to the floor cross member 34. This makes it possible to transmit the impact load F via the floor cross member 34 to the rocker on the opposite side to the rocker to which the collision load F was input, making it possible to distribute the impact load F.

[0064] The shape of the present embodiment is not particularly limited. For example, as a first modification, in the EA section 50, as shown in Fig. 2, in a high-rigidity section (first guiding section) 54 having a higher rigidity than the other energy absorbing sections 52, a high-rigidity section 54A and a high-rigidity section 54B, and a high-rigidity section 54B and a high-rigidity section 54C adjacent to each other in the vehicle width direction overlap each other in the vehicle up-down direction.

[0065] In this embodiment, the lower parts of the high rigidity portion 54A and the high rigidity portion 54B are disposed at positions overlapping with the battery case 22 in a side view of the vehicle, and the upper part of the high rigidity portion 54B and the high rigidity portion 54C are disposed at positions overlapping with the floor cross member 34 in a side view of the vehicle. In addition, the upper wall portion 54C1 of the high rigidity portion 54C and the upper wall portion 34A of the floor cross member 34 are disposed at positions overlapping with each other in a side view of the vehicle.

[0066] In this way, in variant example 1, the high rigidity portions adjacent to each other in the vehicle width direction overlap in the vehicle up-down direction, so that the rigidity of the high rigidity portions 54A, 54B, 54C themselves is further improved compared to the high rigidity portions 48A, 48B, 48D shown in FIG. 1, and the load transmission efficiency of the impact load F input along the vehicle width direction in the overlapping area is improved, making it possible to transmit the impact load more effectively.

[0067] <Second embodiment>

[0068] In the first embodiment described above, for example, as shown in FIG. 1, the EA portion (impact absorbing portion) 42 arranged within the closed cross-sectional portion 40 is configured with a plurality of energy absorbing portions 44 each having a substantially rectangular closed cross-sectional shape when cut along the vehicle width direction and the vehicle up-down direction.

[0069] In contrast, in the second embodiment, the shape of a part of the EA section is significantly different from that of the other energy absorbing sections. For example, as shown in Fig. 3, the EA section 60 includes a plurality of energy absorbing sections 62 each having a substantially rectangular cross-sectional shape and an energy absorbing section 64 each having a triangular cross-sectional shape. Note that a description of the same contents as those in the first embodiment will be omitted.

[0070] In this embodiment, a high-rigidity portion (second guiding portion) 68 having higher rigidity than the other energy absorbing portions 66 among the multiple energy absorbing portions 62 is provided in the lower portion of the EA portion 60 and disposed at a position overlapping with the battery case 22 in a side view of the vehicle. This high-rigidity portion 68 makes it possible to guide the impact load F input from the outside in the vehicle width direction to the fastening portion 32 side. In this embodiment, the impact load F is guided to the fastening portion 32 side via the high-rigidity portion 68, thereby making it possible to reduce the impact load F input to the battery pack 20.

[0071] In this embodiment, an energy absorbing portion (first guiding portion) 64 is provided on the inside in the vehicle width direction of the high rigidity portion 68. This energy absorbing portion 64 is disposed above the fastening portion 32, and includes an inclined portion (first guiding portion) 70 that inclines toward the upper side of the vehicle as it moves toward the inside in the vehicle width direction.

[0072] Therefore, the impact load F can be transmitted toward the floor cross member 34 via the inclined portion 70. The provision of the inclined portion 70 increases the degree of freedom in controlling the load transmission direction, in other words, the degree of freedom in design. In this embodiment, the outer end 70A of the inclined portion 70 is provided on the outer side in the vehicle width direction than the fastening portion 32, and the inner end 70B of the inclined portion 70 is provided on the upper side of the vehicle than the fastening portion 32. As a result, in this embodiment, it is possible to prevent the impact load F from being transmitted beyond the fastening portion 32 to the inner side in the vehicle width direction, and it is possible to protect the battery pack 20.

[0073] <Third embodiment>

[0074] In the first embodiment described above, as shown in FIG. 1, among the multiple energy absorbing sections 44 constituting the EA section 42 in the closed cross-sectional section 40, high rigidity sections 48 are provided in some of the energy absorbing sections, the rigidity of which is increased by changing the plate thickness or the like, and the load transmission efficiency of the impact load F is increased via the high rigidity sections 48, making it possible to guide the impact load F in a predetermined direction toward the inside in the vehicle width direction.

[0075] In contrast, in the third embodiment, as shown in Fig. 4, the EA section 80 itself has a shape capable of guiding the impact load F in a predetermined direction. To specifically explain this embodiment, the EA section 80 is configured to include an upper stage section 82, a middle stage section 84, and a lower stage section 86 along the vertical direction of the vehicle.

[0076] In this embodiment, the upper stage 82 has an outer wall 82A located on the outer side in the vehicle width direction and an inner wall 82B located on the inner side in the vehicle width direction, which are set to be approximately the same length, forming a rectangular shape. In the middle stage 84, the inner wall 84B is formed shorter than the outer wall 84A, forming a trapezoidal shape. Therefore, the lower wall (inclined portion) 84C of the middle stage 84 is inclined upward as it approaches the inside in the vehicle width direction. In addition, the lower stage 86 has a triangular shape with the intersection with the inner wall 84B located on the inner side in the vehicle width direction as the apex, and the lower wall (inclined portion) 86B of the lower stage 86 forms the lower wall of the EA section 80, and is inclined upward as it approaches the inside in the vehicle width direction.

[0077] In this embodiment, the outer wall portion 82A of the upper stage 82 and the upper part of the outer wall portion 84A of the middle stage 84 are positioned in a position overlapping with the floor cross member 34 when viewed from the side of the vehicle, and the lower part of the outer wall portion 84A of the middle stage 84 and the outer wall portion 86A of the lower stage 86 are positioned in a position overlapping with the battery case 22 when viewed from the side of the vehicle.

[0078] Additionally, the inner wall portion 82B of the upper stage portion 82 and the inner wall portion 84B of the middle stage portion 84 are disposed at positions overlapping with the floor cross member 34 in a vehicle side view, and the lower stage portion 86 has a lower wall portion 86B. As a result, the impact load F can be transmitted from the outer side in the vehicle width direction to the floor cross member 34 disposed on the inner side in the vehicle width direction via the upper stage portion 82 and the middle stage portion 84, and can also be transmitted to the floor cross member 34 via the lower wall portion 84C of the middle stage portion 84 and the lower wall portion 86B of the lower stage portion 86. As a result, in this embodiment, it is possible to protect the battery pack 20.

[0079] However, this embodiment is not limited to this. For example, as a first modified example, as shown in Fig. 5, in the EA section 90, an outer wall portion 92A of an upper stage portion 92 and an outer wall portion 92A of a middle stage portion 94 are disposed at positions overlapping with the floor cross member 34 in a side view of the vehicle, and an outer wall portion 96A of a lower stage portion 96 is disposed at a position overlapping with the battery case 22 in a side view of the vehicle.

[0080] Also, the inner wall portions 92B, 94B, 96B may be formed shorter than the outer wall portions 92A, 94A, 96A of the upper stage portion 92, the middle stage portion 94, and the lower stage portion 96, respectively, to form a trapezoidal shape. As a result, the lower wall portion (inclined portion) 92C of the upper stage portion 92, the lower wall portion (inclined portion) 94C of the middle stage portion 94, and the lower wall portion (inclined portion) 96C of the lower stage portion 96 are each formed so as to incline toward the floor cross member 34 located above as they move inward in the vehicle width direction.

[0081] In the first modification, the outer wall portion 92A of the upper stage portion 92 and the upper portion of the outer wall portion 94A of the middle stage portion 94 are disposed in a position overlapping with the floor cross member 34 in a side view of the vehicle, and the lower portion of the outer wall portion 94A of the middle stage portion 94 and the outer wall portion 96A of the lower stage portion 96 are disposed in a position overlapping with the battery case 22 in a side view of the vehicle. Also, the inner wall portion 92B of the upper stage portion 92, the inner wall portion 94B of the middle stage portion 94, and the inner wall portion 96B of the lower stage portion 96 are disposed in a position overlapping with the floor cross member 34 in a side view of the vehicle.

[0082] Therefore, in this embodiment, the impact load F can be transmitted to the floor cross member 34 via the upper stage portion 92, the middle stage portion 94, and the lower stage portion 96, and can also be transmitted to the floor cross member 34 via the lower wall portion 92C of the upper stage portion 92, the lower wall portion 94C of the middle stage portion 94, and the lower wall portion 96C of the lower stage portion 96.

[0083] <Additional Notes> The vehicle underbody structure according to the present invention may be formed by appropriately combining the following configurations.

[0084] (Configuration 1) The vehicle comprises a pair of rockers extending in the fore-and-aft direction of the vehicle on both outer sides in the vehicle width direction, a cross member extending in the vehicle width direction above the vehicle of a battery connected to the pair of rockers and between the pair of rockers, with both ends in the extension direction connected to the pair of rockers, and an impact absorbing section provided within the pair of rockers, positioned so as to overlap the cross member and the battery in a side view of the vehicle, and provided with a first guiding section that guides impact loads input from the outside in the vehicle width direction toward the cross member.

[0085] (Configuration 2) The impact absorbing portion is configured to include a plurality of energy absorbing portions arranged along the vehicle vertical direction and vehicle width direction and capable of absorbing impact energy through plastic deformation, and the first guiding portion is configured by some of the energy absorbing portions.

[0086] (Configuration 3) The energy absorbing portion has a closed cross-sectional shape when cut along the vehicle width direction.

[0087] (Configuration 4) The energy absorbing portion constituting the first guide portion has higher rigidity than the other energy absorbing portions.

[0088] (Configuration 5) The battery is fastened to the locker via a fastening portion, and the impact absorbing portion further includes a second guiding portion that guides the impact load toward the fastening portion.

[0089] (Configuration 6) The energy absorbing portion constituting the second guide portion has higher rigidity than the other energy absorbing portions other than the first guide portion.

[0090] (Configuration 7) The first guiding portion is arranged such that, among the energy absorption parts constituting the first guiding portion, the energy absorption parts provided on the inner side in the vehicle width direction are positioned higher on the vehicle than the energy absorption parts provided on the outer side in the vehicle width direction.

[0091] (Configuration 8) In the first guiding portion, at least a portion of the energy absorbing portions adjacent to each other in the vehicle width direction overlaps with each other in the vehicle up-down direction.

[0092] (Configuration 9) The first guide portion includes an inclined portion that inclines toward the upper side of the vehicle as it approaches the inside in the vehicle width direction.

[0093] (Configuration 10) The outer end portion of the inclined portion in the vehicle width direction is located outside the fastening portion that is fastened to the rocker in the vehicle width direction, and the inner end portion of the inclined portion in the vehicle width direction is located above the vehicle than the fastening portion.

[0094] In addition, the present invention can be implemented in various modifications without departing from the spirit and scope of the present invention. Furthermore, the scope of the present invention is not limited to the above-described embodiment. [Explanation of symbols]

[0095] 10 Vehicle underbody structure 12 Vehicles 16 Rocca 20 Battery pack (battery) 32 Fastening Part 34 Floor cross member (cross member) 42 EA section (shock absorbing section) 44 Energy absorption section 46 Energy absorbing part (other energy absorbing part) 48 High rigidity part (1st guide part, 2nd guide part) 48A High rigidity part (1st guide part, 2nd guide part) 48B High rigidity part (1st induction part) 48C High rigidity part (second induction part) 48D High rigidity part (1st guidance part) 50 EA section (shock absorbing section) 52 Energy absorbing part (other energy absorbing part) 54 High rigidity part (1st guidance part) 54A High rigidity part (1st induction part) 54B High rigidity part (1st induction part) 54C High rigidity part (1st induction part) 60 EA section (shock absorbing section) 62 Energy absorption section 64 Energy absorption section (first induction section) 66 Energy absorbing part (other energy absorbing part) 68 High rigidity part (second induction part) 70 Inclined section (first guidance section) 70A Outer end (Outer end in the vehicle width direction at the inclined portion) 70B Inner end (inner end in the vehicle width direction at the inclined portion) 80 EA section (shock absorbing section) 82 Upper section (1st guidance section) 84 Middle part (1st guidance part) 84C Lower wall part (slanted part, first guide part) 86 Lower section (1st guidance section) 86B Lower wall part (slanted part, first guide part) 90 EA section (shock absorbing section) 92 Upper section (1st guidance section) 92C Lower wall part (slanted part, first guide part) 94 Middle part (1st guidance part) 94C Lower wall part (slanted part, first guide part) 96 Lower section (1st guidance section) 96C Lower wall part (slanted part, first guide part) F Impact load

Claims

1. A pair of rockers extending in a vehicle front-rear direction on both outer sides in a vehicle width direction; a cross member extending in a vehicle width direction between the pair of rockers and above the vehicle battery connected to the pair of rockers, the cross member having both ends in the extending direction connected to the pair of rockers, an impact absorbing portion provided in each of the pair of rockers and arranged so as to overlap the cross member and the battery in a vehicle side view, the impact absorbing portion including a first guide portion that guides an impact load input from the outside in the vehicle width direction toward the cross member; A vehicle undercarriage comprising:

2. 2. The vehicle undercarriage structure according to claim 1, wherein the impact absorbing portion includes a plurality of energy absorbing portions arranged along the vehicle vertical direction and the vehicle width direction and capable of absorbing impact energy by plastic deformation, and the first guiding portion is formed by a portion of the energy absorbing portions.

3. The vehicle underbody structure according to claim 2 , wherein the energy absorbing portion has a closed cross-sectional shape when cut along the vehicle width direction.

4. The vehicle underbody structure according to claim 2 , wherein the energy absorbing portion constituting the first guide portion has a higher rigidity than other energy absorbing portions.

5. The battery is fastened to the locker via a fastening portion, The vehicle underbody structure according to claim 1 , wherein the impact absorbing portion includes a second guide portion that guides the impact load toward the fastening portion.

6. The vehicle underbody structure according to claim 5 , wherein the energy absorbing portion constituting the second guide portion has a higher rigidity than other energy absorbing portions other than the first guide portion.

7. 3. The vehicle underbody structure according to claim 2, wherein, of the energy absorption portions constituting the first guiding portion, an energy absorption portion provided on an inner side in the vehicle width direction is disposed higher on the vehicle than an energy absorption portion provided on an outer side in the vehicle width direction.

8. The vehicle underbody structure according to claim 2 , wherein in the first guide portion, at least a portion of the energy absorbing portions adjacent to each other in a vehicle width direction overlaps with each other in a vehicle up-down direction.

9. The vehicle underbody structure according to claim 1 , wherein the first guide portion includes an inclined portion that inclines upwardly toward the vehicle as it extends inward in a vehicle width direction.

10. 10. The vehicle undercarriage structure according to claim 9, wherein an outer end portion of the inclined portion on the outer side in the vehicle width direction is provided outward in the vehicle width direction from a fastening portion fastened to the rocker, and an inner end portion of the inclined portion on the inner side in the vehicle width direction is provided above the vehicle from the fastening portion.

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