Vehicle undercarriage

Abstract

The objective is to obtain a vehicle understructure that suppresses the impact of side collision loads applied to the rocker section on the passenger compartment while also suppressing an increase in the vehicle's overall weight. [Solution] In the lower part of the vehicle body 12A, a reinforcing panel 50 is arranged between a pair of rocker sections 24 on the front and rear sides of the cross member section 30, so as to overlap with these rocker sections 24 when viewed from the vehicle width direction. The reinforcing panel 50 is provided with alternating recesses 50A that are convex toward the lower side of the vehicle and extend in the vehicle width direction, and protrusions 50B that are convex toward the upper side of the vehicle and extend in the vehicle width direction, in the vehicle front-rear direction.

Description

Technical Field

[0001] The present invention relates to a vehicle rear lower structure.

Background Art

[0002] Patent Document 1 below discloses an invention related to a vehicle structure. In this vehicle structure, a cross member portion is disposed between a pair of rocker portions extending in the vehicle front-rear direction, and a side collision load input to the vehicle can be supported by the cross member portion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in the above prior art, when a side collision load is input to the rocker portion, it is conceivable that at a portion of the rocker portion not supported by the cross member portion, the rocker portion is deformed inward in the vehicle width direction and the side collision load also affects the vehicle interior side.

[0005] To avoid this, it is conceivable to increase the plate thickness of the rocker portion to ensure the rigidity of the rocker portion against the side collision load. However, if such a configuration is adopted, the vehicle body is likely to become heavier. That is, the above prior art has room for improvement in suppressing the influence of the side collision load input to the rocker portion on the vehicle interior side while suppressing the weight increase of the vehicle body.

[0006] In consideration of the above facts, an object of the present invention is to obtain a vehicle lower structure capable of suppressing the influence of a side collision load input to the rocker portion on the vehicle interior side while suppressing the weight increase of the vehicle body.

Means for Solving the Problems

[0007] The vehicle understructure according to the first embodiment includes a pair of rocker sections arranged on both sides in the vehicle width direction at the underside of the vehicle body and extending in the vehicle longitudinal direction, at least one cross member section extending in the vehicle width direction and having both ends connected to the rocker sections, and a reinforcing panel section arranged between the pair of rocker sections on the front or rear side of the cross member section so as to overlap with the rocker sections when viewed from the vehicle width direction, and having a recess that is convex toward the vehicle downwards and extends in the vehicle width direction, and a protrusion that is convex toward the vehicle upwards and extends in the vehicle width direction, which are alternately provided in the vehicle longitudinal direction.

[0008] According to the first embodiment of the vehicle understructure, a pair of rocker sections are arranged on both sides in the vehicle width direction at the underside of the vehicle body, and these rocker sections each extend in the vehicle longitudinal direction. At least one cross member section extending in the vehicle width direction has both ends connected to the rocker sections. Therefore, in this embodiment, the cross member section can support the side impact load applied to the rocker sections.

[0009] Incidentally, when a side impact load is applied to the rocker section, in areas of the rocker section that are not supported by the cross member, the rocker section may deform inward in the vehicle width direction, and the side impact load may also affect the inside of the passenger compartment.

[0010] In this regard, one might consider increasing the thickness of the rocker section to ensure its rigidity against side impact loads. However, adopting such a configuration would increase the weight of the vehicle, which is undesirable from the standpoint of reducing vehicle weight.

[0011] In this embodiment, a reinforcing panel is arranged between a pair of rocker sections on the front or rear side of the cross member section, so as to overlap these rocker sections when viewed from the vehicle width direction. The reinforcing panel is provided with alternating recesses that protrude downwards towards the vehicle and extend in the vehicle width direction, and protrusions that protrude upwards towards the vehicle and extend in the vehicle width direction, in the vehicle front-rear direction.

[0012] Therefore, in this embodiment, the second moment of area of ​​the cross-section of the reinforcing panel section as viewed from the vehicle width direction is secured, and when a side collision load is input to the rocker section, the side collision load can be distributed and supported by the reinforcing panel section at the points in the rocker section that are not supported by the cross member section.

[0013] As a result, it is possible to suppress the deformation of the rocker section inward in the vehicle width direction due to the side impact load without increasing the thickness of the rocker section.

[0014] The vehicle understructure according to the second embodiment is characterized in that, in the vehicle understructure according to the first embodiment, a flat plate-shaped flat panel portion is arranged on the upper side of the vehicle of the reinforcing panel portion.

[0015] According to the vehicle understructure of the second embodiment, a flat plate-shaped flat panel is arranged on the upper side of the reinforcing panel, and the load from the inside of the vehicle can be received by the flat panel and distributed to the reinforcing panel. Therefore, in this embodiment, equipment and the like arranged on the underside of the flat panel and reinforcing panel can be protected from load from the inside of the vehicle.

[0016] The vehicle understructure according to the third embodiment is a vehicle understructure according to the second embodiment in which the flat panel portion is joined to the convex portion and together with a part of the reinforcing panel portion including the concave portion, the cross section when viewed from the vehicle width direction is a closed cross section, forming a concave closed cross section structure.

[0017] According to the third embodiment of the vehicle understructure, the flat panel portion is joined to the convex portion of the reinforcing panel portion, thereby forming a concave closed-section structure portion together with a part of the reinforcing panel portion including a concave portion, resulting in a closed cross-section when viewed from the vehicle width direction. As a result, loads from the inside of the vehicle can be absorbed by deforming the concave closed-section structure portion, and the likelihood of protecting equipment and other items located on the underside of the vehicle of the flat panel portion and reinforcing panel portion from loads from the inside of the vehicle can be increased.

[0018] The vehicle understructure according to the fourth embodiment further comprises a battery located between the pair of rocker sections on the underside of the vehicle of the cross member section, in the vehicle understructure according to any one of the first to third embodiments, and the reinforcing panel section is located above the battery section.

[0019] According to the vehicle understructure of the fourth embodiment, when a side collision load is applied to the rocker section, the reinforcing panel section can support the side collision load and protect the battery in areas where the cross member section is not located above the battery.

[0020] The vehicle understructure according to the fifth embodiment is such that, in the vehicle understructure according to the fourth embodiment, the reinforcing panel portion is attached to the upper surface of the battery case that constitutes the outer casing of the battery.

[0021] According to the vehicle understructure of the fifth embodiment, since the reinforcing panel is attached to the upper surface of the battery case that constitutes the outer shell of the battery, a degree of freedom in the mounting position of the reinforcing panel can be ensured. As a result, even if the position of the cross member is changed according to the vehicle specifications, the position of the reinforcing panel can be set to a position suitable for supporting side collision loads.

[0022] The vehicle understructure according to the sixth embodiment is configured such that, in the vehicle understructure according to the fifth embodiment, the recess and the upper surface are joined together to form a convex-side closed-section structure in which a part of the reinforcing panel including the protrusion and a part of the battery case have a closed cross-section when viewed from the vehicle width direction.

[0023] According to the sixth embodiment of the vehicle understructure, the recess of the reinforcing panel and the upper surface of the battery case are joined together to form a convex-side closed-section structure in which a part of the reinforcing panel including a protrusion and a part of the battery case have a closed cross section when viewed from the vehicle width direction. Therefore, when a side impact load is applied to the rocker section, the side impact load can be distributed and supported by the convex-side closed-section structure in areas of the rocker section that are not supported by the cross member, thereby suppressing the application of the side impact load to the battery side.

[0024] The vehicle underbody structure according to the seventh aspect is the vehicle underbody structure according to the fourth aspect that cites the first aspect, in which a flat panel portion is arranged above the vehicle of the reinforcing panel portion, the flat panel portion is joined to the convex portion, the reinforcing panel portion is attached to the upper surface of a battery case that constitutes an outer shell of the battery, and the width in the vehicle front-rear direction of the upper surface portion joined to the flat panel portion in the convex portion is larger than the width in the vehicle front-rear direction of the lower surface portion joined to the upper surface in the concave portion.

[0025] According to the vehicle underbody structure according to the seventh aspect, the width in the vehicle front-rear direction of the upper surface portion joined to the flat panel portion in the convex portion of the reinforcing panel portion is larger than the width in the vehicle front-rear direction of the lower surface portion joined to the upper surface of the battery case in the concave portion of the reinforcing panel portion. For this reason, it is possible to secure an area for receiving a load from the vehicle interior side in the reinforcing panel portion, disperse this load in the reinforcing panel portion, and reduce the influence of this load on the battery.

[0026] The vehicle underbody structure according to the eighth aspect is the vehicle underbody structure according to any one of the fifth to seventh aspects, further including a plurality of longitudinal members provided inside the battery case and extending in the vehicle front-rear direction so as to intersect the concave portion and the convex portion when viewed from the vehicle up-down direction and spaced apart in the vehicle width direction, and a load transmission portion arranged inside the battery case and capable of transmitting a load between the upper portion of the battery case and the longitudinal members.

[0027] According to the vehicle underbody structure according to the eighth aspect, a plurality of longitudinal members are provided inside the battery case. These longitudinal members extend in the vehicle front-rear direction so as to intersect the concave portion and the convex portion of the reinforcing panel portion when viewed from the vehicle up-down direction, and are arranged at intervals in the vehicle width direction.

[0028] Furthermore, a load transmission unit is located inside the battery case, and this load transmission unit is capable of transmitting load between the upper part of the battery case and the front-rear member. As a result, loads from the inside of the vehicle interior can be transmitted and supported to the front-rear member via the load transmission unit from the recesses and protrusions of the reinforcing panel, thereby reducing the impact of this load on the inside of the battery case.

[0029] The vehicle understructure according to the ninth embodiment is configured such that, in the vehicle understructure according to the eighth embodiment, the load transmission section includes an end plate section of a battery cell which constitutes part of the battery and is arranged along the longitudinal member section.

[0030] According to the vehicle understructure of the ninth embodiment, the load transmission section is configured to include an end plate portion of a battery cell that constitutes part of the battery and is arranged along the longitudinal member section. Therefore, it is possible to configure part of the load transmission path from the reinforcing panel section to the longitudinal member section without arranging a separate member inside the battery case.

[0031] The vehicle understructure according to the tenth embodiment is a vehicle understructure according to any one of the first to ninth embodiments, wherein the end of the reinforcing panel portion in the vehicle width direction is in contact with the inner side surface of the rocker portion in the vehicle width direction.

[0032] According to the tenth embodiment of the vehicle understructure, the vehicle width direction end of the reinforcing panel portion is in contact with the inner side surface of the rocker portion in the vehicle width direction, and the side impact load applied to the rocker portion can be directly supported by the reinforcing panel portion. [Effects of the Invention]

[0033] As described above, the vehicle understructure according to the present invention has the excellent effect of suppressing the effect of side collision loads applied to the rocker section on the passenger compartment side, while also suppressing an increase in the weight of the vehicle body. [Brief explanation of the drawing]

[0034] [Figure 1] This is a schematic plan view showing the configuration of a vehicle to which the vehicle understructure according to this embodiment is applied. [Figure 2] This is a schematic cross-sectional view showing the configuration of a vehicle to which the vehicle understructure according to this embodiment is applied (a cross-sectional view showing the state when cut along line 2-2 in Figure 1). [Figure 3] This is a schematic cross-sectional view showing the configuration of a vehicle to which the vehicle understructure according to this embodiment is applied (a cross-sectional view showing the state when cut along line 3-3 in Figure 1). [Figure 4] This is a schematic cross-sectional view (showing a state cut along line 4-4 in Figure 1) illustrating the configuration of the main parts of a vehicle to which the vehicle understructure according to this embodiment is applied. [Figure 5] This is a schematic cross-sectional view (a cross-sectional view showing the state when cut along line 5-5 in Figure 1) of a battery pack and its surrounding parts mounted on a vehicle to which the vehicle understructure according to this embodiment is applied. [Modes for carrying out the invention]

[0035] An example of a vehicle understructure according to the present invention will be described below with reference to Figures 1 to 5. In each figure, arrows FR indicate the front of the vehicle, UP indicates the upper side of the vehicle, and RH indicates the right side in the vehicle width direction.

[0036] First, the general configuration of the vehicle 10 to which the vehicle understructure according to this embodiment is applied will be described using Figures 1 and 2. In this embodiment, the vehicle 10 is basically symmetrical, so in the following, when describing parts common to both sides in the vehicle width direction, the configuration of the right side of the vehicle 10 in the vehicle width direction will be described, and the configuration of the right side in the vehicle width direction will be omitted as appropriate.

[0037] The vehicle body 12 of the vehicle 10 comprises an aluminum die-cast front part 14 that forms the front of the vehicle, a center part 20 that forms the center of the vehicle in the front-rear direction and includes a battery pack 16 and a center frame 18 that holds the battery pack 16, and an aluminum die-cast rear part 22 that forms the rear of the vehicle. The front part 14 is equipped with a power unit (not shown) including a motor, and the vehicle 10 moves when this power unit is driven by electricity supplied from the battery pack 16.

[0038] To describe the configuration of the center frame 18 in more detail, the center frame 18 is composed of a pair of rocker sections 24 that are arranged on both sides in the vehicle width direction at the lower part of the vehicle body 12A and extend in the vehicle longitudinal direction, a front cross section 26 that connects the front ends of the rocker sections 24, and a rear cross section 28 that connects the rear ends of the rocker sections 24.

[0039] The rocker section 24 is made of an extruded aluminum alloy, and its outer circumference 24A is shaped like a rectangular tube extending in the longitudinal direction of the vehicle. The inside of the outer circumference 24A is divided into multiple sections by partition walls 24B.

[0040] Furthermore, the front cross section 26 is made of an extruded aluminum alloy and is shaped like a rectangular tube extending in the vehicle width direction.

[0041] The rear cross section 28 is made of an extruded aluminum alloy and is curved in a convex shape towards the rear of the vehicle.

[0042] Furthermore, a pair of cross member sections 30 are connected to the central parts of the pair of rocker sections 24. These cross member sections 30 are made of extruded aluminum alloy, and their outer circumference is shaped like a rectangular tube extending in the vehicle width direction, while the inside of this outer circumference is partitioned in the vehicle front-rear direction by a bulkhead.

[0043] The cross member sections 30 are arranged at predetermined intervals from one another in the vehicle's longitudinal direction, and both ends are connected to the rocker section 24 via connecting members (not shown). The cross member sections 30 also support front and rear seats (not shown), and the cross member sections 30 can be considered to constitute a part of the floor section 12B1 of the passenger compartment 12B.

[0044] On the other hand, the main part of the battery pack 16 is located on the underside of the rocker section 24 of the vehicle and is positioned between the pair of rocker sections 24 when viewed from the vertical direction of the vehicle. As also shown in Figure 5, the battery pack 16 is composed of a battery case 32 that forms its outer shell and a plurality of battery cells 34 housed in the battery case 32.

[0045] The battery case 32 is primarily made of an aluminum alloy and comprises a case upper 36 which forms the upper part of the vehicle and a case lower 38 which forms the lower part of the vehicle.

[0046] As shown in Figure 3, the case upper 36 is composed of an upper wall portion 36A that constitutes the upper part of the vehicle and extends in the vehicle width direction and the vehicle longitudinal direction, a peripheral wall portion 36B provided along the peripheral edge of the upper wall portion 36A, and a flange portion 36C that extends from the lower edge of the peripheral wall portion 36B to the outside of the battery case 32.

[0047] On the other hand, the case lower 38 is composed of a lower wall portion 38A that constitutes the lower part of the vehicle and extends in the vehicle width direction and the vehicle longitudinal direction, a peripheral wall portion 38B provided along the peripheral edge of the lower wall portion 38A, and a flange portion 38C that extends from the lower edge of the peripheral wall portion 38B to the outside of the battery case 32.

[0048] The case upper 36 and case lower 38 are integrated by the flange portion 36C and flange portion 38C being attached by mounting members (not shown). The flange portions 36C and 38C are located on the underside of the rocker portion 24 and are attached to the rocker portion 24 via fastening members (not shown).

[0049] Returning to Figure 5, inside the battery case 32, multiple (three as an example) longitudinal member portions 40 extending in the longitudinal direction of the vehicle are provided on the upper surface of the lower wall portion 38A of the case lower 38, spaced apart in the vehicle width direction. The three longitudinal member portions 40 are arranged symmetrically with respect to the center in the vehicle width direction when viewed from the vertical direction of the vehicle (see Figure 1).

[0050] More specifically, the front-rear member portion 40 has a hat-like cross-sectional shape when viewed from the front-rear direction of the vehicle, with the underside of the vehicle open, and its flange portion 40A is joined to the lower wall portion 38A by a joint (not shown) such as welding.

[0051] Furthermore, cell holding sections 42, which have an L-shaped cross-section when viewed from the front-rear direction of the vehicle, are provided on one side and the other side in the vehicle width direction of the front-rear member section 40, and battery cells 34 are held in these cell holding sections 42.

[0052] The battery cell 34 is composed of a rectangular tubular cell case portion 44 that forms its outer shell and has the vehicle width direction as its longitudinal direction, an end plate 46 that serves as a load transmission portion that seals the end of the cell case portion 44, and an electrode body (not shown) arranged inside the cell case portion 44.

[0053] The battery cells 34 configured as described above are arranged in multiple stacks in the vehicle's longitudinal direction, with their thickness direction being the vehicle's longitudinal direction, and along the longitudinal member portion 40. The upper portion of the battery cell 34 is housed inside the case upper 36, and the lower portion of the battery cell 34 is housed inside the case lower 38.

[0054] Furthermore, with the battery cell 34 positioned in the battery case 32 as described above, the end plate 46 is positioned so as to overlap with the flange portion 40A of the front-rear member portion 40 when viewed from the top-down direction of the vehicle. In other words, the end plate 46 is positioned along the front-rear member portion 40. The upper end of the end plate 46 on the vehicle side is in close proximity to the upper wall portion 36A of the case upper 36.

[0055] Furthermore, in this embodiment, as shown in Figure 1, reinforcing boards 48 are arranged on the front and rear sides of the vehicle of a pair of cross member sections 30, between a pair of rocker sections 24 when viewed from the vehicle width direction above the battery case 32.

[0056] As shown in Figure 4, the reinforcing board 48 is composed of a reinforcing panel section 50 and a flat panel section 52 positioned on the vehicle side of the reinforcing panel section 50.

[0057] The reinforcing panel section 50 is, for example, constructed by press-forming a steel plate, and is rectangular in shape when viewed from the top or bottom of the vehicle. It has a recess 50A that is convex on the lower side of the vehicle and extends in the vehicle width direction, and a protrusion 50B that is convex on the upper side of the vehicle and extends in the vehicle width direction, which are alternately provided in the front-rear direction of the vehicle. The recess 50A and the protrusion 50B are formed from one end in the vehicle width direction to the other end in the vehicle width direction of the reinforcing panel section 50.

[0058] More specifically, the recess 50A is composed of a lower surface portion 50A1 that constitutes the lower part of the vehicle, and a pair of vertical wall portions 50A2 that extend upward from the lower surface portion 50A1.

[0059] On the other hand, the protruding portion 50B is composed of an upper portion 50B1 which constitutes the upper part of the vehicle and whose width in the vehicle longitudinal direction is greater than the width of the lower portion 50A1 in the vehicle longitudinal direction, and a pair of vertical wall portions 50B2 which extend downward from the upper portion 50B1 to the vehicle.

[0060] Furthermore, since the recessed portion 50A and the convex portion 50B are provided continuously in the longitudinal direction of the vehicle, there is no visible boundary between them. In other words, although the vertical wall portion 50A2 and the vertical wall portion 50B2 are given different reference numerals for convenience, they refer to the same part.

[0061] Furthermore, as shown in Figure 1, the recessed portion 50A and the protruding portion 50B are perpendicular to the front-rear member portion 40 of the battery case 32 when viewed from the vertical direction of the vehicle.

[0062] Returning to Figure 4, the flat panel section 52 is, for example, made of steel plate and is a rectangular flat plate when viewed from the vertical direction of the vehicle. This flat panel section 52 is joined to the upper surface 50B1 of the convex section 50B by a joint (not shown) made by spot welding or the like, and together with a part of the reinforcing panel section 50 including the concave section 50A, it forms a concave closed section structure 53 in which the cross section when viewed from the width direction of the vehicle is a closed section.

[0063] Furthermore, the lower surface 50A1 of the recess 50A and the upper surface 36A1 of the upper wall 36A of the case upper 36 are joined by a joint 54 made of adhesive or the like, thereby forming a convex-side closed-section structure 56 in which a part of the reinforcing panel 50 including the convex portion 50B and a part of the upper wall 36A have a closed cross-section when viewed from the vehicle width direction.

[0064] As shown in Figure 3, the reinforcing board 48 configured as described above is positioned to overlap with the rocker section 24 when viewed from the vehicle width direction. Furthermore, the outer end of the reinforcing board 48 in the vehicle width direction is spaced at a predetermined distance from the inner side surface 24C of the rocker section 24 in the vehicle width direction.

[0065] (Operation and effects of this embodiment) Next, the operation and effects of this embodiment will be described.

[0066] In this embodiment, as shown in Figure 1, a pair of rocker sections 24 are arranged on both sides in the vehicle width direction of the lower part 12A of the vehicle body, and these rocker sections 24 each extend in the vehicle longitudinal direction. The ends of the cross member section 30, which extends in the vehicle width direction, are connected to the rocker sections 24. Therefore, in this embodiment, the cross member section 30 can support the lateral collision load input to the rocker sections 24.

[0067] Incidentally, when a side impact load is applied to the rocker section 24, in areas of the rocker section 24 that are not supported by the cross member section 30, the rocker section 24 may deform inward in the vehicle width direction, and the side impact load may also affect the inside of the passenger compartment 12B.

[0068] In this regard, one might consider increasing the thickness of the rocker section 24 to ensure the rigidity of the rocker section 24 against side impact loads. However, adopting such a configuration would increase the weight of the vehicle body 12, which is undesirable from the standpoint of reducing the weight of the vehicle body 12.

[0069] In this embodiment, as shown in Figures 3 and 4, a reinforcing panel 50 is arranged between a pair of rocker sections 24 on the front and rear sides of the cross member section 30, so as to overlap with these rocker sections 24 when viewed from the vehicle width direction. The reinforcing panel 50 is provided with alternating recesses 50A that are convex toward the lower side of the vehicle and extend in the vehicle width direction, and protrusions 50B that are convex toward the upper side of the vehicle and extend in the vehicle width direction, in the vehicle front-rear direction.

[0070] Therefore, in this embodiment, the second moment of area of ​​the cross section of the reinforcing panel 50 as viewed from the vehicle width direction is secured, and when a side collision load is input to the rocker section 24, the side collision load can be distributed and supported by the reinforcing panel 50 at the portion of the rocker section 24 that is not supported by the cross member section 30.

[0071] As a result, without increasing the thickness of the rocker section 24, it is possible to suppress deformation of the rocker section 24 inward in the vehicle width direction due to the side impact load.

[0072] Furthermore, in this embodiment, a flat panel section 52 is positioned on the upper side of the reinforcing panel section 50, allowing the flat panel section 52 to receive loads from inside the passenger compartment 12B (for example, concentrated loads from stiletto heels, etc.) and distribute these loads to the reinforcing panel section 50. Therefore, in this embodiment, equipment and the like positioned on the lower side of the flat panel section 52 and the reinforcing panel section 50 can be protected from loads from inside the passenger compartment 12B.

[0073] Furthermore, in this embodiment, the flat panel portion 52 is joined to the convex portion 50B of the reinforcing panel portion 50, thereby forming a concave closed-section structure portion 53 together with a part of the reinforcing panel portion 50 including the concave portion 50A, resulting in a closed cross-section when viewed from the vehicle width direction. As a result, the load from inside the passenger compartment 12B is absorbed by deforming the concave closed-section structure portion 53, increasing the likelihood that equipment and other items placed on the underside of the vehicle of the flat panel portion 52 and the reinforcing panel portion 50 are protected from loads from inside the passenger compartment 12B.

[0074] Furthermore, in this embodiment, when a side impact load is input to the rocker section 24, the reinforcing panel section 50 can support the side impact load and protect the battery pack 16 in areas where the cross member section 30 is not located above the battery pack 16.

[0075] Furthermore, in this embodiment, since the reinforcing panel 50 is attached to the upper surface 36A1 of the battery case 32 that constitutes the outer shell of the battery pack 16, a degree of freedom in the mounting position of the reinforcing panel 50 can be ensured. As a result, even if the position of the cross member 30 is changed according to the specifications of the vehicle 10, the position of the reinforcing panel 50 can be set to a position suitable for supporting side collision loads.

[0076] Furthermore, in this embodiment, the recess 50A of the reinforcing panel 50 and the upper surface 36A1 of the battery case 32 are joined together to form a convex-side closed-section structure 56, in which a part of the reinforcing panel 50 including the convex portion 50B and a part of the battery case 32 have a closed cross section when viewed from the vehicle width direction. Therefore, when a side collision load is input to the rocker portion 24, the side collision load can be distributed and supported by the convex-side closed-section structure 56 at the parts of the rocker portion 24 that are not supported by the cross member portion 30, thereby suppressing the input of the side collision load to the battery pack 16.

[0077] Furthermore, in this embodiment, the width in the vehicle longitudinal direction of the upper surface portion 50B1 joined to the flat panel portion 52 at the convex portion 50B of the reinforcing panel portion 50 is greater than the width in the vehicle longitudinal direction of the lower surface portion 50A1 joined to the upper surface 36A of the battery case 32 at the concave portion 50A of the reinforcing panel portion 50. Therefore, an area of ​​the reinforcing panel portion 50 that can receive the load from the inside of the passenger compartment 12B is secured, and this load is distributed to the reinforcing panel portion 50, thereby reducing the influence of this load on the battery pack 16.

[0078] Furthermore, in this embodiment, a plurality of front-to-rear member portions 40 are provided inside the battery case 32. As shown in Figure 1, these front-to-rear member portions 40 extend in the front-to-rear direction of the vehicle so as to intersect with the recesses 50A and protrusions 50B of the reinforcing panel portion 50 when viewed from the vertical direction of the vehicle, and are arranged with spacing in the vehicle width direction.

[0079] Furthermore, an end plate 46 for the battery cell 34 is positioned inside the battery case 32, and this end plate 46 is capable of transmitting load between the case upper 36 of the battery case 32 and the front-rear member portion 40. As a result, the load from inside the vehicle compartment 12B can be transmitted and supported to the front-rear member portion 40 via the end plate 46 from the recess 50A and protrusion 50B of the reinforcing panel portion 50, thereby reducing the effect of this load on the inside of the battery case 32.

[0080] In addition, in this embodiment, as described above, the end plate 46 functions as a load transmission unit that transmits the load from the inside of the passenger compartment 12B from the reinforcing panel 50 to the longitudinal member 40. Therefore, it is possible to constitute part of the load transmission path from the reinforcing panel 50 to the longitudinal member 40 without having to separately arrange a member that functions as a load transmission unit inside the battery case 32.

[0081] As described above, in this embodiment, it is possible to suppress the effect of the side impact load input to the rocker section 24 on the passenger compartment 12B side while suppressing the increase in weight of the vehicle body 12.

[0082] <Supplementary explanation of the above embodiment> In the embodiment described above, the reinforcing board 48 is joined to the battery case 32, and its outer end in the vehicle width direction is spaced apart from the inner side surface 24C of the rocker section 24 in the vehicle width direction. However, the reinforcing board 48 may be directly supported by the center frame 18. For example, depending on the specifications of the vehicle 10, the reinforcing board 48 may be stretched between a pair of rocker sections 24, and the outer end of the reinforcing board 48 in the vehicle width direction may be attached to the side surface 24C by mounting members or welding.

[0083] With this configuration, the vehicle-width end of the reinforcing panel 50 is in contact with the side surface 24C of the rocker section 24, and the side impact load applied to the rocker section 24 can be directly supported by the reinforcing panel 50.

[0084] Furthermore, it becomes possible to install the reinforcing board 48 even without the battery pack 16, and the vehicle understructure according to this embodiment can be applied to engine vehicles and the like that are not equipped with a battery pack 16.

[0085] Furthermore, in this embodiment, two cross member sections 30 are provided with respect to the center frame 18, but depending on the specifications of the vehicle 10, a configuration in which only one cross member section 30 is provided with respect to the center frame 18 may be adopted.

[0086] Furthermore, depending on the specifications of the vehicle 10, if the distance between the cross member sections 30 becomes large, a reinforcing board 48 may be placed between the cross member sections 30. For example, the reinforcing board 48 may be stretched between a pair of cross member sections 30, and the front and rear ends of the reinforcing board 48 may be attached to the cross member sections 30 by mounting members or welding.

[0087] In addition, in this embodiment, the reinforcing panel portion 50 was joined to the upper surface 36A1 of the upper wall portion 36A of the case upper 36. However, depending on the specifications of the vehicle 10, a configuration may be adopted in which a portion corresponding to the reinforcing panel portion 50 is provided on the upper wall portion 36A. For example, a configuration may be adopted in which a plurality of bulging portions extending in the vehicle width direction and bulging outwards on the upper or lower side of the vehicle are formed at predetermined intervals in the vehicle longitudinal direction, thereby providing the upper wall portion 36A with alternating recesses and protrusions in the vehicle longitudinal direction. [Explanation of Symbols]

[0088] 10 vehicles 12 car bodies 12A Underbody 16 Battery pack (batteries) 24 Locker Department 24C side 30 Cross member section 32 Battery Case 34 battery cells 36 Case Upper (Top) 36A1 Top 40 Front and rear direction member section 46 End plate (load transmission section) 50 Reinforcement panel section 50A recess 50A1 Bottom part 50B protrusion 50B1 Top part 52 Flat panel section 53 Concave side closed section structure 56 Convex side closed section structure

Claims

1. A pair of rocker sections are positioned on both sides in the vehicle width direction at the lower part of the vehicle body and extend in the vehicle longitudinal direction, A cross member portion that extends in the vehicle width direction and has both ends connected to the rocker portion, A reinforcing panel is provided on the front or rear side of the cross member portion between the pair of rocker portions, so as to overlap with the rocker portions when viewed from the vehicle width direction, and has a recess that is convex downwards and extends in the vehicle width direction, and a protrusion that is convex upwards and extends in the vehicle width direction, which are alternately provided in the vehicle front-rear direction. A vehicle understructure having the following characteristics.

2. A flat panel section is positioned on the upper side of the vehicle where the reinforcing panel section is located. The vehicle understructure according to claim 1.

3. The flat panel portion, when joined with the convex portion, together with a part of the reinforcing panel portion including the concave portion, forms a concave-side closed-section structure whose cross-section, as viewed from the vehicle width direction, is a closed section. The vehicle understructure according to claim 2.

4. The cross member portion further comprises a battery positioned between the pair of rocker portions on the underside of the vehicle, The reinforcing panel portion is located on the upper side of the vehicle above the battery. The vehicle understructure according to any one of claims 1 to 3.

5. The reinforcing panel is attached to the upper surface of the battery case that constitutes the outer casing of the battery. The vehicle understructure according to claim 4.

6. By joining the recess and the upper surface, a convex-side closed-section structure is formed, in which a part of the reinforcing panel including the protrusion and a part of the battery case have a closed cross-section when viewed from the vehicle width direction. The vehicle understructure according to claim 5.

7. A flat panel section is positioned on the upper side of the vehicle above the reinforcing panel section. The flat panel portion is joined to the protrusion portion, The reinforcing panel portion is attached to the upper surface of the battery case that constitutes the outer shell of the battery. The width of the upper surface portion joined to the flat panel portion in the convex portion in the vehicle longitudinal direction is greater than the width of the lower surface portion joined to the upper surface in the concave portion in the vehicle longitudinal direction. The vehicle understructure according to claim 4, referencing claim 1.

8. Multiple front-to-rear member portions are provided inside the battery case and extend in the front-to-rear direction of the vehicle so as to intersect with the recess and the protrusion when viewed from the vertical direction of the vehicle, and are spaced apart in the vehicle width direction. The battery case is further comprising a load transmission unit disposed inside the battery case and capable of transmitting load between the upper part of the battery case and the front-rear member portion. The vehicle understructure according to claim 5.

9. The load transmission section is configured to include an end plate portion of a battery cell that constitutes part of the battery and is arranged along the front-rear member portion. The vehicle understructure according to claim 8.

10. The end of the reinforcing panel portion in the vehicle width direction is in contact with the inner side surface of the rocker portion in the vehicle width direction. The vehicle understructure according to any one of claims 1 to 3.

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