Lower body structure

Abstract

The present invention provides a lower body structure that can transmit loads applied to the vehicle body from the front to the side sills. [Solution] The lower body structure comprises a pair of side sills, reinforcements positioned inside each side sill and extending in the front-rear direction, and brackets connecting the side sills and reinforcements to each other. The side sill comprises a side sill inner and a side sill outer fixed to the outside of the side sill inner in the vehicle width direction and forming a closed cross section together with the side sill inner. The bracket comprises an upper wall extending in the vehicle width direction and fixed to the lower surface of the reinforcement, an inner wall extending downward from the inner end of the upper wall in the vehicle width direction and fixed to the side sill inner, and an outer wall extending downward from the outer end of the upper wall in the vehicle width direction and fixed to the side sill inner and the side sill outer.

Description

Technical Field

[0001] This disclosure relates to a lower body structure.

Background Art

[0002] Patent Document 1 describes a vehicle body structure including a side sill and a reinforcing member disposed in the internal space of the side sill and supported in the internal space by a support member joined to the side sill.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Patent Document 1 does not describe transmitting the load input to the vehicle body from the front side during a small overlap frontal collision to the side sill.

[0005] An object of this disclosure is to provide a lower body structure capable of transmitting the load input to the vehicle body from the front side to the side sill.

Means for Solving the Problems

[0006] One aspect of this disclosure is a floor panel, a pair of side sills respectively disposed at both ends in the vehicle width direction of the floor panel and extending in the front-rear direction, a reinforcement disposed inside each side sill and extending in the front-rear direction, and a bracket connecting the side sill and the reinforcement to each other and includes ; the side sill is a side sill inner, A side sill outer is fixed to the outer side of the side sill inner in the vehicle width direction and together with the side sill inner forms a closed cross section. Equipped with, The aforementioned bracket is An upper wall extending in the vehicle width direction and fixed to the lower surface of the reinforcement, An inner wall extending downward from the inner end in the vehicle width direction of the upper wall and fixed to the side sill inner, An outer wall extending downward from the outer end in the vehicle width direction of the upper wall and fixed to the side sill inner and the side sill outer, The lower body structure is provided, which includes the following features.

[0007] This configuration allows loads applied to the vehicle body from the front to be transmitted to the side sill. Because the bracket is fixed to both the reinforcement and the side sill inner, loads applied to the reinforcement from the front can be transmitted to the side sill inner via the bracket. [Effects of the Invention]

[0008] According to this disclosure, it is possible to provide a lower body structure that can transmit loads applied to the vehicle body from the front to the side sill. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a top view of a lower vehicle body structure according to one embodiment of the present disclosure. [Figure 2] Figure 2 is a cross-sectional view along the line II-II in Figure 1. [Figure 3] Figure 3 is a perspective view of the lower body structure shown in Figure 1, and the side sill outer is omitted from the illustration in Figure 3. [Figure 4] Figure 4 is a perspective view of the bracket shown in Figure 2. [Figure 5] Figure 5 shows the upper surface of the lower body structure around the reinforcement shown in Figure 2, and the side sills are not shown in Figure 5. [Modes for carrying out the invention]

[0010] The following description will explain the lower body structure of a vehicle according to one embodiment of the present disclosure with reference to the attached drawings. The following description is essentially illustrative and is not intended to limit the present disclosure, its applications, or its uses.

[0011] Figure 1 is a top view of a lower body structure 1 according to one embodiment of the present disclosure. The lower body structure 1 is mounted on a vehicle such as an automobile. In this embodiment, the lower body structure 1 is mounted on an electric vehicle. In this specification, the longitudinal direction, lateral direction, and vertical direction of the vehicle on which the lower body structure 1 is mounted may be referred to as the "longitudinal direction," the "vehicle width direction," and the "vertical direction," respectively. In this specification, the side of the vehicle's centerline in the vehicle width direction may be referred to as the "inside in the vehicle width direction," and the side opposite the vehicle's centerline in the vehicle width direction may be referred to as the "outside in the vehicle width direction."

[0012] Referring to Figure 1, the lower body structure 1 comprises a floor panel 10, a pair of side sills 20A and 20B, a first cross member 30, and a second cross member 40. In the following description, when it is not necessary to distinguish between the pair of side sills 20A and 20B, one of the pair of side sills 20A and 20B may simply be referred to as the side sill 20. Also, the first cross member 30 and the second cross member 40 in this embodiment are examples of cross members according to the present disclosure.

[0013] The floor panel 10 constitutes the floor surface of the passenger compartment of a vehicle on which the lower body structure 1 is mounted. The floor panel 10 is a press-formed product made of steel. The floor panel 10 is in a plate shape that extends in the front-rear direction and the vehicle width direction with the vertical direction as the thickness direction. Below the floor panel 10, a battery case 2 (shown in FIG. 2) for housing a vehicle battery (not shown) is arranged. The vehicle of the present embodiment is an electric vehicle and does not include an internal combustion engine and a transmission. Therefore, an exhaust pipe and a propeller shaft are not arranged below the floor panel 10, and a so-called tunnel that protrudes upward in the center of the vehicle width direction and extends in the front-rear direction is not formed in the floor panel 10.

[0014] A pair of side sills 20A and 20B are respectively arranged at both ends in the vehicle width direction of the floor panel 10. That is, the pair of side sills 20A and 20B are arranged at intervals in the vehicle width direction. The side sill 20 extends in the front-rear direction along the outer end in the vehicle width direction of the floor panel 10. The side sill 20 has a rectangular closed cross-section when viewed from the front-rear direction. The side sill 20 is made of steel. The side sill 20 is also a component called a rocker.

[0015] The first cross member 30 is arranged on the upper surface of the floor panel 10. The first cross member 30 extends in the vehicle width direction between the side sills 20A and 20B. The first cross member 30 connects the side sills 20A and 20B to each other. The first cross member 30 is a press-formed product made of a steel plate. The first cross member �0 has a hat shape that opens downward and forms a closed cross-section structure that extends in the vehicle width direction together with the floor panel 10. The first cross member 30 includes a front flange 30a arranged at the front edge and a rear flange 30b arranged at the rear edge. The first cross member 30 is joined to the floor panel 10 by spot welding via the front flange 30a and the rear flange 30b. The first cross member 30 is a seat cross member to which a front seat (not shown) is attached.

[0016] At both ends in the vehicle width direction of the first cross member 30, seat brackets 31 for fixing a front seat (not shown) are attached. The seat bracket 31 is a press-formed product made of a steel plate. The seat bracket 31 is joined to each of the first cross member 30 and the side sill 20 by spot welding. Thereby, the first cross member 30 is connected to a pair of side sills 20A and 20B via the seat bracket 31 at both ends in the vehicle width direction.

[0017] The second cross member 40 is disposed on the upper surface of the floor panel 10. The second cross member 40 is disposed behind the first cross member 30. That is, the second cross member 40 is disposed at an interval in the front-rear direction from the first cross member 30. The second cross member 40 extends in the vehicle width direction between the side sills 20A and 20B. The second cross member 40 connects the side sills 20A and 20B to each other. The second cross member 40 is a press-formed product made of a steel plate. The second cross member 40 has a hat shape opened downward and forms a closed cross-section structure extending in the vehicle width direction together with the floor panel 10. The second cross member 40 includes a front flange 40a disposed at the front edge and a rear flange 40b disposed at the rear edge. The second cross member 40 is joined to the floor panel 10 by spot welding via the front flange 40a and the rear flange 40b.

[0018] At both ends in the vehicle width direction of the second cross member 40, gussets 41 are attached. The gusset 41 is a press-formed product made of a steel plate. The gusset 41 is joined to each of the second cross member 40 and the side sill 20 by spot welding. The second cross member 40 is connected to a pair of side sills 20 via the gusset 41 at both ends in the vehicle width direction.

[0019] The second cross member 40 has lower rigidity against loads from the outside in the vehicle width direction (hereinafter sometimes referred to as side impact loads) compared to the first cross member 30. Furthermore, the second cross member 40 does not have a seat bracket for fixing a seat (not shown). In other words, the second cross member 40 does not have the function of supporting the load of the seat.

[0020] Figure 2 is a cross-sectional view along the line II-II in Figure 1. Figure 2 shows the area around the side sill 20A connected to the second cross member 40. Figure 3 is a perspective view of the lower body structure 1, in which the side sill 20 is not shown.

[0021] Referring to Figure 2, the side sill 20 comprises a side sill inner 21 and a side sill outer 22 positioned on the outside of the side sill inner 21 in the vehicle width direction. Both the side sill inner 21 and the side sill outer 22 are press-formed products made of steel plate.

[0022] The side sill inner 21 is a hat-shaped plate material that opens outward in the vehicle width direction. Specifically, the side sill inner 21 comprises an upper wall portion 21a extending in the vehicle width direction, a side wall portion 21b extending downward from the inner end of the upper wall portion 21a in the vehicle width direction, and a lower wall portion 21c extending outward in the vehicle width direction from the lower end of the side wall portion 21b. The side sill inner 21 comprises a flange 21d extending upward from the outer end of the upper wall portion 21a in the vehicle width direction, and a flange 21e extending downward from the outer end of the lower wall portion 21c in the vehicle width direction.

[0023] The side sill outer 22 is a hat-shaped plate material that opens inward in the vehicle width direction. Specifically, the side sill outer 22 comprises an upper wall portion 22a extending in the vehicle width direction, a side wall portion 22b extending downward from the outer end of the upper wall portion 22a in the vehicle width direction, and a lower wall portion 22c extending inward in the vehicle width direction from the lower end of the side wall portion 22b. The side sill outer 22 comprises a flange 22d extending upward from the inner end of the upper wall portion 22a in the vehicle width direction, and a flange 22e extending downward from the inner end of the lower wall portion 22c in the vehicle width direction.

[0024] The side sill inner 21 and the side sill outer 22 are joined together by spot welding, with a space defined between them. Specifically, the flange 21d of the side sill inner 21 and the flange 22d of the side sill outer 22 are joined to each other by spot welding, and the flange 21e of the side sill inner 21 and the flange 22e of the side sill outer 22 are joined to each other by spot welding. As a result, the side sill 20 is configured as a closed cross-sectional structure extending in the front-rear direction.

[0025] The lower body structure 1 includes a reinforcement 50 positioned inside each side sill 20 and a bracket 60 that secures the reinforcement 50 to the side sill 20. Figure 2 shows only one of the pair of side sills 20A, 20B, side sill 20A, but the other side sill 20B also has a reinforcement 50 and bracket 60 positioned inside it.

[0026] The reinforcement 50 is located inside the side sill 20. The reinforcement 50 extends in the longitudinal direction along the entire length of the side sill 20. In this embodiment, as shown in Figure 3, the reinforcement 50 extends forward beyond the front end of the side sill 20 (only the side sill inner 21 is shown in Figure 3). The front end of the reinforcement 50 is located below the hinge pillar 3 (only the inner pillar is shown in Figure 3).

[0027] As shown in Figure 2, the reinforcement 50 is aligned with the first cross member 30 and the second cross member 40 in the vertical direction. The reinforcement 50 is an extruded aluminum material. The reinforcement 50 has a longitudinal direction extending in the front-rear direction. In the cross-section shown in Figure 2, the reinforcement 50 has a narrow rectangular closed cross-sectional shape in the vehicle width direction. The reinforcement 50 has a generally uniform cross-sectional shape along its entire length in the longitudinal direction. The reinforcement 50 comprises a first vertical wall 51, a second vertical wall 52, a first horizontal wall 53, a second horizontal wall 54, a first inner wall 55, and a second inner wall 56.

[0028] The first vertical wall 51 is plate-shaped with its longitudinal direction in the front-rear direction, its transverse direction in the up-down direction, and its thickness direction in the vehicle width direction. In the cross-section shown in Figure 2, the first vertical wall 51 extends vertically as a whole. The first vertical wall 51 constitutes a part of the outer shape of the reinforcement 50. Specifically, the first vertical wall 51 constitutes the outer side wall of the reinforcement 50 in the vehicle width direction.

[0029] The second vertical wall 52 is plate-shaped with its longitudinal direction in the front-rear direction, its transverse direction in the up-down direction, and its thickness direction in the vehicle width direction. In the cross-section shown in Figure 2, the second vertical wall 52 extends vertically as a whole. The second vertical wall 52 constitutes a part of the outer shape of the reinforcement 50. Specifically, the second vertical wall 52 constitutes the inner side wall of the reinforcement 50 in the vehicle width direction. The second vertical wall 52 is positioned inward in the vehicle width direction relative to the first vertical wall 51. The second vertical wall 52 is positioned at a distance from the first vertical wall 51 in the vehicle width direction.

[0030] The first lateral wall 53 is plate-shaped with its longitudinal direction in the front-rear direction, its transverse direction in the vehicle width direction, and its thickness direction in the vertical direction. In the cross-section shown in Figure 2, the first lateral wall 53 extends in the vehicle width direction so as to connect the upper end of the first vertical wall 51 and the upper end of the second vertical wall 52 to each other. The first lateral wall 53 constitutes a part of the outer shape of the reinforcement 50. Specifically, the first lateral wall 53 constitutes the upper wall of the reinforcement 50.

[0031] The second lateral wall 54 is plate-shaped with its longitudinal direction in the front-rear direction, its transverse direction in the vehicle width direction, and its thickness direction in the vertical direction. In the cross-section shown in Figure 2, the second lateral wall 54 extends in the vehicle width direction so as to connect the lower end of the first longitudinal wall 51 and the lower end of the second longitudinal wall 52 to each other. The second lateral wall 54 constitutes a part of the outer shape of the reinforcement 50. Specifically, the second lateral wall 54 constitutes the lower wall of the reinforcement 50. The second lateral wall 54 is positioned below the first lateral wall 53. The second lateral wall 54 is positioned at a distance from the first lateral wall 53 in the vertical direction.

[0032] The first inner wall 55 is plate-shaped with its longitudinal direction in the front-rear direction, its transverse direction in the up-down direction, and its thickness direction in the vehicle width direction. In the cross-section shown in Figure 2, the first inner wall 55 extends vertically so as to connect the first transverse wall 53 and the second transverse wall 54 to each other. The first inner wall 55 is positioned between the first longitudinal wall 51 and the second longitudinal wall 52 in the vehicle width direction.

[0033] The second inner wall 56 is plate-shaped with its longitudinal direction in the front-rear direction, its transverse direction in the up-down direction, and its thickness direction in the vehicle width direction. In the cross-section shown in Figure 2, the second inner wall 56 extends vertically so as to connect the first transverse wall 53 and the second transverse wall 54 to each other. The second inner wall 56 is positioned between the second longitudinal wall 52 and the first inner wall 55 in the vehicle width direction. In other words, the second inner wall 56 is positioned inward in the vehicle width direction relative to the first inner wall 55.

[0034] Inside the reinforcement 50, a rectangular cross-sectional interior space is defined by the first vertical wall 51, the second vertical wall 52, the first horizontal wall 53, and the second horizontal wall 54. This interior space is divided into three closed cross-sectional spaces by the first inner wall 55 and the second inner wall 56.

[0035] The reinforcement 50 is divided into three regions in the vehicle width direction. Specifically, the reinforcement 50 is divided into three parts having an outer region R1, an intermediate region R2, and an inner region R3.

[0036] The outer region R1 is the region of the reinforcement 50 located between the first longitudinal wall 51 and the first inner wall 55 in the vehicle width direction. The outer region R1 includes the portion of the first transverse wall 53 and the second transverse wall 54 that extends in the vehicle width direction between the first longitudinal wall 51 and the second inner wall 56.

[0037] The intermediate region R2 is the region of the reinforcement 50 located between the first inner wall 55 and the second inner wall 56 in the vehicle width direction. The intermediate region R2 includes the portion of the first lateral wall 53 and the second lateral wall 54 that extends in the vehicle width direction between the first inner wall 55 and the second inner wall 56.

[0038] The inner region R3 is the area of ​​the reinforcement 50 located between the second longitudinal wall 52 and the second inner wall 56 in the vehicle width direction. The inner region R3 includes the portion of the first transverse wall 53 and the second transverse wall 54 that extends in the vehicle width direction between the second longitudinal wall 52 and the second inner wall 56.

[0039] The reinforcement 50 is fastened to the side sill inner 21. The second vertical wall 52 of the reinforcement 50 is bolted to the side wall portion 21b of the side sill inner 21 in the vehicle width direction.

[0040] The bracket 60 is located inside the side sill 20. The bracket 60 is located below the reinforcement 50 inside the side sill 20. The bracket 60 is made of steel. The bracket 60 is provided at multiple locations (two locations in this embodiment) located inside the side sill 20, spaced apart from each other in the front-rear direction. At least a portion of the bracket 60 is located in a position that overlaps with the hinge pillar 3 or center pillar 4 extending upward from the side sill 20 in a vehicle side view. Specifically, the two brackets 60 are provided so as to partially overlap with the lower portion 3a of the hinge pillar 3 that extends in the front-rear direction to connect to the side sill 20, and the lower portion 4a of the center pillar 4 that extends in the front-rear direction to connect to the side sill 20, respectively, in a vehicle side view.

[0041] As shown in Figure 2, the bracket 60 is U-shaped when viewed in the front-to-back direction. The bracket 60 comprises an upper wall 60a, an inner wall 60b, and an outer wall 60c.

[0042] The upper wall 60a is plate-shaped, with its thickness oriented vertically and extending in the front-rear and vehicle width directions. The upper wall 60a is positioned facing the second side wall 54 of the reinforcement 50 in the vertical direction. The upper wall 60a is fixed to the lower surface of the reinforcement 50.

[0043] The inner wall 60b extends downward from the inner end of the upper wall 60a in the vehicle width direction. The inner wall 60b is positioned facing the side wall portion 21b of the side sill inner 21. The inner wall 60b is fixed to the side sill inner 21.

[0044] The outer wall 60c extends downward from the outer end of the upper wall 60a in the vehicle width direction. The outer wall 60c faces the inner wall 60b and is positioned with a gap in the vehicle width direction. The outer wall 60c is fixed to the side sill inner 21 and the side sill outer 22.

[0045] Bracket 60 is fastened to reinforcement 50. The upper wall 60a of bracket 60 is bolted to the second lateral wall 54 in the inner region R3 of reinforcement 50. That is, the fixing portion, i.e., the fastening point, between the upper wall 60a and reinforcement 50 is located inward in the vehicle width direction from the center of reinforcement 50 in the vehicle width direction.

[0046] The bracket 60 is joined to the side sill 20 by spot welding. The inner wall 60b of the bracket 60 is joined to the side wall portion 21b of the side sill inner 21 in the vehicle width direction by spot welding. The outer wall 60c of the bracket 60 is sandwiched between the flange 21e of the side sill inner 21 and the flange 22e of the side sill outer 22 at its lower end, and is joined to the side sill inner 21 and the side sill outer 22 in a triple-layered spot welding configuration.

[0047] Figure 4 is a perspective view of the bracket 60. Referring to Figure 4, the bracket 60 of this embodiment has a divided structure comprising a first part 61 and a second part 62 that is separate from the first part 61.

[0048] The first part 61 is a press-formed product made of steel plate. The first part 61 is L-shaped when viewed in the front-to-back direction. The first part 61 comprises a first vertical plate 61a and a first horizontal plate 61b. The first vertical plate 61a is a plate shape with the vehicle width direction as the plate thickness direction and extending in the vertical and front-to-back directions. The first vertical plate 61a constitutes the inner wall 60b of the bracket 60. The first horizontal plate 61b is a plate shape with the vertical direction as the plate thickness direction and extending in the vehicle width direction and front-to-back directions. The first horizontal plate 61b extends outward in the vehicle width direction from the upper end of the first vertical plate 61a.

[0049] The second part 62 is a press-formed product made of steel plate. The second part 62 is L-shaped when viewed in the front-to-back direction. The second part 62 comprises a second vertical plate 62a and a second horizontal plate 62b. The second vertical plate 62a is plate-shaped with the vehicle width direction as the plate thickness direction and extending in the vertical and front-to-back directions. The second vertical plate 62a faces the first vertical plate 61a in the vehicle width direction and is positioned on the outside of the first vertical plate 61a in the vehicle width direction. The second vertical plate 62a constitutes the outer wall 60c of the bracket 60. The second horizontal plate 62b is plate-shaped with the vertical direction as the plate thickness direction and extending in the vehicle width direction and front-to-back directions. The second horizontal plate 62b extends inward in the vehicle width direction from the upper end of the second vertical plate 62a.

[0050] The first horizontal plate 61b of the first component 61 and the second horizontal plate 62b of the second component 62 are superimposed in the vertical direction. The first horizontal plate 61b and the second horizontal plate 62b are joined by welding while superimposed in the vertical direction. The second horizontal plate 62b, together with the first horizontal plate 61b, constitutes the upper wall 60a of the bracket 60.

[0051] In this embodiment, the inner wall 60b and the outer wall 60c are connected in the vehicle width direction only via the upper wall 60a. In other words, the bracket 60 does not have any members connecting the inner wall 60b and the outer wall 60c except for the upper wall 60a.

[0052] Figure 5 is a top view of the lower body structure 1 showing the area around the reinforcement 50, and the side sill 20 is not shown in Figure 5. Referring to Figure 5, the reinforcement 50 comprises a first part 57, a second part 58, and a third part 59.

[0053] The first part 57 is positioned to overlap with the first cross member 30 when viewed from the side of the vehicle. In other words, the first part 57 is the portion that overlaps with the first cross member 30 when viewed from the outside in the width direction of the vehicle. The first part 57 is aligned with the first cross member 30 in the longitudinal direction.

[0054] The second portion 58 is positioned so as not to overlap with either the first cross member 30 or the second cross member 40 when viewed from the side of the vehicle. In other words, the second portion 58 is a portion that does not overlap with either the first cross member 30 or the second cross member 40 when viewed from the inside in the vehicle width direction. The second portion 58 is positioned offset from the first cross member 30 and the second cross member 40 in the longitudinal direction. In this embodiment, the second portion 58 is divided into three sections, including a section 58a located in front of the first cross member 30, a section 58b located behind the first cross member 30 and in front of the second cross member 40, and a section 58c located behind the second cross member 40.

[0055] The third section 59 is positioned to overlap with the second cross member 40 when viewed from the side of the vehicle. In other words, when viewed from the outside in the width direction of the vehicle, the third section 59 and the second cross member 40 are aligned with the second cross member 40 in the longitudinal direction.

[0056] The rigidity of the second part 58 is lower than that of the first part 57. In this embodiment, a plurality of holes 70 are formed in the second part 58, and each hole 70 penetrates the first lateral wall 53 and the second lateral wall 54 in the vertical direction. When a load is applied to the reinforcement 50 from the outside in the vehicle width direction, stress concentration occurs around the plurality of holes 70 formed in the second part 58, making the plurality of holes 70 likely to become the starting point of deformation. As a result, the rigidity of the second part 58, in which the plurality of holes 70 are formed, is lower than that of the first part 57, in which no holes are formed.

[0057] In this embodiment, the plurality of holes 70 include a plurality of holes 70A formed in the outer region R1 and a plurality of holes 70B formed in the intermediate region R2. The plurality of holes 70A are arranged in a line in the front-to-back direction with spacing between them in the front-to-back direction. The plurality of holes 70B are arranged in a line in the front-to-back direction with spacing between them in the front-to-back direction.

[0058] The rigidity of the third section 59 is lower than that of the first section 57 and higher than that of the second section 58. In this embodiment, a plurality of holes 71 are formed in the third section 59, and each hole 71 penetrates the first lateral wall 53 and the second lateral wall 54 in the vertical direction. When a load is applied to the reinforcement 50 from the outside in the vehicle width direction, stress concentration occurs around the plurality of holes 71 formed in the third section 59, making the plurality of holes 71 likely to become the starting point of deformation. As a result, the rigidity of the second section 58, in which the plurality of holes 71 are formed, is lower than that of the first section 57, in which no holes are formed. Furthermore, the number, size, shape, and arrangement of the plurality of holes 71 formed in the third section 59 are set so that the rigidity of the third section 59 is higher than that of the second section. In this embodiment, the opening area of ​​each hole 71 formed in the third section 59 is smaller than the opening area of ​​each hole 71 formed in the second section 58.

[0059] The second portion 58 has a shape in which its rigidity increases toward the inside in the vehicle width direction. In this embodiment, the number, size, shape, and arrangement of the multiple holes 70 formed in the second portion 58 are set so that the rigidity of the second portion 58 increases toward the inside in the vehicle width direction. In this embodiment, no holes are formed in the inner region R3 of the second portion 58, and the opening area of ​​each hole 70B formed in the intermediate region R2 is smaller than the opening area of ​​each hole 70A formed in the outer region R1. As a result, the rigidity of the second portion 58 tends to increase in stages toward the inside in the vehicle width direction. Specifically, in the second portion 58, the rigidity of the inner region R3 is higher than the rigidity of the intermediate region R2, and the rigidity of the intermediate region R2 is higher than the rigidity of the outer region R1.

[0060] The second portion 58 has a shape in which its rigidity increases as it approaches that of the first portion 57 or the third portion 59. In this embodiment, the number, size, shape, and arrangement of the multiple holes 70 formed in the second portion 58 are set such that the rigidity of the second portion 58 increases as it approaches that of the first portion 57 or the third portion 59. In this embodiment, in section 58a, the opening area of ​​the hole 70 closer to the first portion 57 of two adjacent holes 70 in the front-rear direction is smaller than the opening area of ​​the hole 70 further from the first portion 57. Also, in section 58b, the opening area of ​​the hole 70 closer to the center of section 58b in the front-rear direction is larger than the opening area of ​​the hole 70 further from the center of section 58b in the front-rear direction. In section 58c, the opening area of ​​the hole 70 closer to the third portion 59 of two adjacent holes 70 in the front-rear direction is smaller than the opening area of ​​the hole 70 further from the first portion 57. As a result, in each section 58a to 58c, the rigidity of the second section 58 tends to increase as it approaches that of the first section 57 or the third section 59.

[0061] The lower body structure 1 according to this embodiment provides the following effects.

[0062] (1) The lower body structure 1 according to this embodiment is Floor panel 10 and A pair of side sills 20A and 20B are positioned at both ends of the floor panel 10 in the vehicle width direction and extend in the front-rear direction, A reinforcement 50 is positioned inside each side sill 20 and extends in the front-to-back direction, Bracket 60 connects the side sill 20 and the reinforcement 50 to each other. Equipped with, Side sill 20 is Side sill inner 21 and, The side sill outer 22 is fixed to the outer side in the vehicle width direction of the side sill inner 21 and together with the side sill inner 21 forms a closed cross section. Equipped with, Bracket 60 is, An upper wall 60a extending in the vehicle width direction and fixed to the lower surface of the reinforcement 50, An inner wall 60b extends downward from the inner end in the vehicle width direction of the upper wall 60a and is fixed to the side sill inner 21, An outer wall 60c extends downward from the outer end in the vehicle width direction of the upper wall 60a and is fixed to the side sill inner 21 and the side sill outer 22. It is equipped with.

[0063] According to the lower body structure 1 of this embodiment, loads input to the vehicle body from the front can be transmitted to the side sill 20. In this embodiment, since the bracket 60 is fixed to both the reinforcement 50 and the side sill inner 21, loads input to the reinforcement 50 from the front can be transmitted to the side sill inner 21 via the bracket 60.

[0064] In this embodiment, the reinforcement 50 is fastened to the side sill 20. The load applied to the reinforcement 50 from the front can be distributed and transmitted to the side sill 20 via two paths: one that transmits the load directly from the reinforcement 50 to the side sill 20, and another that transmits the load from the reinforcement 50 to the side sill 20 via the bracket 60. Therefore, compared to a configuration that has only one path that transmits the load directly from the reinforcement 50 to the side sill 20, the load acting on the fastening point between the reinforcement 50 and the side sill 20 can be reduced.

[0065] (2) The inner wall 60b and the outer wall 60c are spaced apart from each other in the vehicle width direction and are connected to each other only through the upper wall 60a.

[0066] According to the lower body structure 1 of this embodiment, the amount of energy absorbed by the reinforcement 50 against side impact loads can be increased. In a configuration in which the inner wall 60b and the outer wall 60c are connected by members other than the upper wall 60a that extends in the vehicle width direction, when the side sill 20 is subjected to a side impact load, the compression of the reinforcement 50 in the vehicle width direction is inhibited, and the amount of energy absorbed by the reinforcement 50 against side impact loads may be reduced. In contrast, in this embodiment, since the inner wall 60b and the outer wall 60c are connected to each other only via the upper wall 60a, the amount of energy absorbed by the reinforcement 50 against side impact loads can be increased compared to a configuration in which they are connected by members other than the upper wall 60a that extends in the vehicle width direction.

[0067] (3) The fixing portion between the upper wall 60a and the reinforcement 50 is positioned inward in the vehicle width direction from the center of the reinforcement 50 in the vehicle width direction.

[0068] According to the lower body structure 1 of this embodiment, the amount of energy absorbed by the reinforcement 50 against side impact loads can be increased. In a configuration where the fixing portion between the upper wall 60a and the reinforcement 50 is located outside the vehicle width direction of the center of the reinforcement 50 in the vehicle width direction, when the side sill 20 receives a side impact load, the compression of the reinforcement 50 in the vehicle width direction is inhibited by the bracket 60, and the amount of energy absorbed by the reinforcement 50 against side impact loads may be reduced. In contrast, in this embodiment, the fixing portion between the upper wall 60a and the reinforcement 50 is located inside the vehicle width direction of the center of the reinforcement 50 in the vehicle width direction, so the amount of energy absorbed by the reinforcement 50 against side impact loads can be increased compared to a configuration where the fixing portion is located outside the vehicle width direction of the center of the reinforcement 50 in the vehicle width direction.

[0069] (4) The lower body structure 1 is positioned on the upper surface of the floor panel 10 and further comprises a second cross member 40 that extends in the vehicle width direction and connects a pair of side sills 20A and 20B to each other. The bracket 60 is positioned such that, in the front-rear direction (i.e., in a side view of the vehicle), at least a portion of it overlaps with the second cross member 40.

[0070] According to the lower body structure 1 of this embodiment, the amount of energy absorbed by the reinforcement 50 against side impact loads can be increased. This is because at least a portion of the bracket 60 is positioned overlapping the second cross member 40 in the longitudinal direction. When a side impact load acts on the reinforcement 50, the bracket 60 is subjected to both the side impact load and the reaction force from the second cross member 40 against the side impact load. As a result, when a side impact load acts on the reinforcement 50, the bracket 60 does not remain crushed, which can be prevented from hindering the compression of the reinforcement 50. Consequently, the amount of energy absorbed by the reinforcement 50 against side impact loads can be increased.

[0071] (5) At least a portion of the bracket 60 is positioned to overlap with the hinge pillar 3 or center pillar 4 extending upward from the side sill 20 in the front-rear direction (i.e., in a side view of the vehicle).

[0072] (6) The inner wall 60b is joined to the side sill inner 21 by welding.

[0073] According to the lower body structure 1 of this embodiment, loads applied to the vehicle body from the front can be reliably transmitted to the side sill 20. Generally, the shear strength of welded joints is higher than that of fastened joints such as bolts. Therefore, when a load is applied to the reinforcement 50 from the front, the load can be more reliably transmitted from the reinforcement 50 to the side sill 20 via the bracket 60.

[0074] (7) The bracket 60 is a divided structure having a first component 61 that constitutes the outer wall 60c and a second component 62 that, together with the first component 61, constitutes the upper wall 60a and also constitutes the inner wall 60b.

[0075] According to this embodiment, a lower body structure 1 that can efficiently transmit the load applied to the vehicle body from the front to the side sill 20 can be easily manufactured.

[0076] (modified version) This disclosure is not limited to the configurations described in the embodiments above, and various modifications are possible.

[0077] [Note] The lower body structure relating to this disclosure provides the following embodiments.

[0078] [Aspect 1] Floor panel and A pair of side sills are positioned at both ends of the floor panel in the vehicle width direction and extend in the front-rear direction, Reinforcement is located inside each side sill and extends in the front-to-back direction, A bracket connecting the side sill and the reinforcement to each other. Equipped with, The aforementioned side sill is Side sill inner, A side sill outer is fixed to the outer side of the side sill inner in the vehicle width direction and together with the side sill inner forms a closed cross section. Equipped with, The aforementioned bracket is An upper wall extending in the vehicle width direction and fixed to the lower surface of the reinforcement, An inner wall extending downward from the inner end in the vehicle width direction of the upper wall and fixed to the side sill inner, An outer wall extending downward from the outer end in the vehicle width direction of the upper wall and fixed to the side sill inner and the side sill outer, A lower body structure equipped with this.

[0079] [Aspect 2] The lower body structure according to Embodiment 1, wherein the inner wall and the outer wall are spaced apart from each other in the vehicle width direction and are connected to each other only through the upper wall.

[0080] [Aspect 3] The lower body structure according to embodiment 1 or 2, wherein the fixing portion between the upper wall and the reinforcement is located inward in the vehicle width direction from the center of the reinforcement in the vehicle width direction.

[0081] [Aspect 4] The floor panel is further provided with a cross member positioned on the upper surface, extending in the vehicle width direction, and connecting the pair of side sills to each other. The lower body structure according to any one of embodiments 1 to 3, wherein the bracket is positioned such that at least a portion of it overlaps with the cross member in the front-rear direction (i.e., the bracket is positioned such that at least a portion of it overlaps with the cross member when viewed from the side of the vehicle).

[0082] [Aspect 5] The lower body structure according to any one of embodiments 1 to 4, wherein at least a portion of the bracket is positioned to overlap with a pillar extending upward from the side sill in the front-rear direction (i.e., at least a portion of the bracket is positioned to overlap with a pillar extending upward from the side sill in a side view of the vehicle).

[0083] [Aspect 6] The lower body structure according to any one of embodiments 1 to 5, wherein the inner wall is joined to the side sill inner by welding.

[0084] [Aspect 7] The lower vehicle body structure according to any one of embodiments 1 to 6, wherein the bracket has a divided structure comprising a first component that constitutes the outer wall and a second component that, together with the first component, constitutes the upper wall and also constitutes the inner wall. [Explanation of Symbols]

[0085] 1. Lower body structure 2 Battery Cases 3. Hinged pillar 10 Floor Panels 20 Side sill 21 Side sill inner 21a Upper wall part 21b Side wall part 21c Lower wall part 21d flange 22e flange 22 Side sill outer 22a Upper wall part 22b Side wall part 22c Lower wall part 22d flange 22e flange 30. First cross member (cross member) 31 Seat Bracket 40. Second cross member (cross member) 41 gusset 50 Reinforcement 51. First vertical wall 52 Second Vertical Wall 53. First side wall 54 Second side wall 55 First Inner Wall 56 Second Inner Wall 57 Part 1 58 Part 2 59 Part 3 60 bracket 60a Upper wall 60b inner wall 60c exterior wall 61 Part 1 61a First vertical board 61b 1st horizontal board 62 Part 2 62a Second vertical plate 62b 2nd horizontal board 70 holes 71 holes

Claims

1. Floor panel and A pair of side sills are positioned at both ends of the floor panel in the vehicle width direction and extend in the front-rear direction, Reinforcement is located inside each side sill and extends in the front-to-back direction, A bracket connecting the side sill and the reinforcement to each other. Equipped with, The aforementioned side sill is Side sill inner, A side sill outer is fixed to the outer side of the side sill inner in the vehicle width direction and together with the side sill inner forms a closed cross section. Equipped with, The aforementioned bracket is An upper wall extending in the vehicle width direction and fixed to the lower surface of the reinforcement, An inner wall extending downward from the inner end in the vehicle width direction of the upper wall and fixed to the side sill inner, An outer wall extending downward from the outer end in the vehicle width direction of the upper wall and fixed to the side sill inner and the side sill outer, A lower body structure equipped with this.

2. The lower body structure according to claim 1, wherein the inner wall and the outer wall are spaced apart from each other in the vehicle width direction and are connected to each other only through the upper wall.

3. The lower body structure according to claim 1 or 2, wherein the fixing portion between the upper wall and the reinforcement is positioned inward in the vehicle width direction from the center of the reinforcement in the vehicle width direction.

4. The floor panel is further provided with a cross member positioned on the upper surface, extending in the vehicle width direction, and connecting the pair of side sills to each other. The lower body structure according to claim 1, wherein the bracket is positioned such that at least a portion of it overlaps with the cross member in the front-rear direction.

5. The lower body structure according to claim 1, wherein at least a portion of the bracket is arranged to overlap with a pillar extending upward from the side sill in the front-rear direction.

6. The lower body structure according to claim 1, wherein the inner wall is joined to the side sill inner by welding.

7. The lower body structure according to claim 1, wherein the bracket has a divided structure comprising a first component that constitutes the outer wall and a second component that, together with the first component, constitutes the upper wall and also constitutes the inner wall.

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