JP2024087403A - Vehicle body structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle body structure capable of protecting a battery when a side-face collision occurs.

SOLUTION: A vehicle body structure 1A includes: a pair of side sills 10a and 10b that are present so as to extend along the back-and-forth direction of a vehicle; a battery case 30 which stores therein a battery module 40, and which is placed between the pair of side sills 10a and 10b; a bracket 50 which is placed between the battery case 30 and the pair of side sills 10a and 10b, and which connects the battery case 30 to the pair of side sills 10a and 10b; and a cross member 60 which is located above the battery case 30, and which is present so as to extend along the vehicle widthwise direction of the vehicle.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to the body structure of a vehicle such as an automobile.

The electric vehicle includes a pair of left and right side sills arranged on the sides of the vehicle body, a pair of left and right rear frames extending rearward from the rear ends of the left and right side sills, a floor panel connecting the inner members of the left and right side sills, and a battery box mounted below the floor panel (see, for example, Patent Document 1). The battery box has multiple mounting brackets that protrude outward in the vehicle width direction, and these mounting brackets are attached to the undersides of the inner members of the left and right side sills (see, for example, Patent Document 1 (Figure 8)).

JP 2021-142763 A

In the conventional electric vehicle body structure described above, mounting brackets are connected to the undersides of a pair of side sills, and while these mounting brackets allow the lower part of the side sill to absorb the collision energy generated by a side collision of the vehicle, the upper part of the side sill cannot fully absorb the collision energy. As a result, when the side of the electric vehicle collides with a pole such as a utility pole, the upper part of the side sill is crushed and deformed more than the lower part, causing the pole to intrude above the battery box, placing a large load on the battery.

The problem that this invention aims to solve is to provide a vehicle body structure that can protect the battery in the event of a side collision.

The present invention solves the above problem by providing a cross member that is positioned above the battery case and extends along the vehicle width direction, in addition to a bracket that is disposed between the battery case and a pair of side sills and connects the battery case to the pair of side sills.

According to the present invention, in addition to the bracket that is disposed between the battery case and the pair of side sills and connects the battery case to the pair of side sills, a cross member is provided that is positioned above the battery case and extends along the vehicle width direction, so that resistance against input during a side collision can be obtained from both the bracket and the cross member. This makes it possible to prevent poles and other objects from entering the vicinity of the battery case and protect the battery.

FIG. 1 is a plan view showing a first embodiment of a vehicle body structure according to the present invention. FIG. 2 is a cross-sectional view taken along line II-II in FIG. FIG. 3 is a side view showing a first embodiment of the vehicle body structure according to the present invention. FIG. 4 is an exploded perspective view showing an example of a vehicle body structure according to the present invention. FIG. 5 is a plan view showing a modified example of the vehicle body structure according to the present invention.

The first embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a plan view showing the first embodiment of the vehicle body structure 1A according to the present invention, Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1, Fig. 3 is a side view showing the first embodiment of the vehicle body structure 1A according to the present invention, and Fig. 4 is an exploded perspective view showing an example of the vehicle body structure 1A according to the present invention.

As shown in FIG. 1, the vehicle body structure 1A in this embodiment includes a pair of side sills 10a, 10b, a first bulkhead 15, a pair of rear side members 20a, 20b, a second bulkhead 25, a battery case 30, a bracket 50, a cross member 60, and a floor panel 70.

As shown in Figures 1 to 3, the side sills 10a and 10b have a closed cross section and extend in the fore-and-aft direction of the vehicle. The side sills 10a and 10b are composed of a side sill outer 11 and a side sill inner 12.

As shown in FIG. 2, the side sill outer 11 of the side sill 10a has a hat-shaped cross section that curves and protrudes toward the outside of the vehicle (the left side in FIG. 2). This side sill outer 11 has an upper flange 11a at its upper end and a lower flange 11b at its lower end.

On the other hand, the side sill inner 12 has a hat-shaped cross-sectional shape that curves and protrudes toward the inside of the vehicle (the right side in FIG. 2). Like the side sill outer 11, this side sill inner 12 also has an upper flange 12a at its upper end and a lower flange 12b at its lower end.

At the top of the side sill 10a, the upper flanges 11a and 12a are adjacent to each other along the vehicle width direction, and the opposing surfaces of the upper flanges 11a and 12a are welded to each other. At the bottom of the side sill 10a, the lower flanges 11b and 12b are adjacent to each other along the vehicle width direction, and the opposing surfaces of the lower flanges 11b and 12b are welded to each other. This results in a closed cross section of the side sill 10a. Although the side sill 10b is not shown in FIG. 2, the side sill 10b has the same structure as the side sill 10a.

As shown in Figures 1 and 3, a first bulkhead 15 is disposed inside each of the side sills 10a, 10b. As shown in Figure 4, the first bulkhead 15 has a U-shape that opens to the outside of the vehicle. This first bulkhead 15 reinforces the side sills 10a, 10b and is a member for transmitting lateral forces from the side sills 10a, 10b to the rear side members 20a, 20b. This first bulkhead 15 includes a first partition portion 16, a second partition portion 17, a connecting portion 18, and an intermediate portion 19.

The first partition 16 is a plate-shaped portion that divides the internal space of the side sills 10a, 10b in the front-rear direction. This first partition 16 extends left and right from the inner surface of the side sill outer 11 to the inner surface of the side sill inner 12. Similarly, the second partition 17 is a plate-shaped portion that divides the internal space of the side sills 10a, 10b in the front-rear direction, and is located further forward of the vehicle than the first partition 16. This second partition 17, like the first partition 16, also extends left and right from the inner surface of the side sill outer 11 to the inner surface of the side sill inner 12. In addition, the first partition 16 and the second partition 17 are inclined so as to move away from each other as they move toward the outside of the vehicle.

The connecting portion 18 is a plate-like member that is interposed between the first and second partition portions 16, 17 and connects the ends of the first and second partition portions 16, 17 on the inside in the vehicle direction. The connecting portion 18 extends in the vertical direction and faces the inner surface of the side sill inner panel 12. The interposed portion 19 is a plate-like member that connects the inner surfaces of the first partition portion 16, the second partition portion 17, and the connecting portion 18, and reinforces the first bulkhead 15. In other words, it prevents the first partition portion 16, the second partition portion 17, and the connecting portion 18 from moving relative to each other due to an input or the like, which would cause the first bulkhead 15 to deform.

As shown in Figures 1 to 3, a pair of rear side members 20a, 20b are connected to the inner side surfaces of a pair of left and right side sills 10a, 10b, respectively. As shown in Figures 1 and 2, the rear side members 20a, 20b have a closed cross section and extend in the fore-and-aft direction of the vehicle.

As shown in FIG. 2, the rear side members 20a and 20b are composed of a lower member 21 and an upper member 22. The lower member 21 of the rear side member 20a is connected to the side sill inner 12 of the side sill 10a by welding or the like. The lower member 21 has a cross-sectional shape that curves and protrudes downward. On the other hand, the upper member 22 is located above the lower member 21 and is connected to the lower member 21. In this embodiment, both ends of the lower member 21 in the vehicle width direction and both ends of the upper member 22 in the vehicle width direction are connected by welding or the like. Note that the rear side member 20b is not shown in FIG. 2, but the rear side member 20b has the same configuration as the rear side member 20a.

As shown in FIG. 1, a second bulkhead 25 is disposed inside each of the rear side members 20a and 20b. In this embodiment, the second bulkhead 25 is disposed adjacent to the first bulkhead 15 along the vehicle width direction, and the first and second bulkheads 15 and 25 are disposed substantially flush with each other in the vehicle front-rear direction.

As shown in FIG. 4, the second bulkhead 25 has a U-shape that opens downward. This second bulkhead 25 reinforces the rear side members 20a, 20b and is a member for transmitting the input transmitted from the side sills 10a, 10b to the cross member 60. This second bulkhead 25 has a third partition portion 26, a fourth partition portion 27, and a connecting portion 28.

The third partition portion 26 is a plate-shaped portion that divides the internal space of the rear side members 20a, 20b in the front-rear direction. This third partition portion 26 extends along the vehicle width direction in the internal space of the rear side members 20a, 20b. Similarly, the fourth partition portion 27 is a plate-shaped portion that divides the internal space of the rear side members 20a, 20b in the front-rear direction, and is located further forward of the vehicle than the third partition portion 26. This fourth partition portion 27, like the third partition portion 26, also extends along the vehicle width direction in the internal space of the rear side members 20a, 20b.

The connecting portion 28 is a plate-shaped member that is interposed between the third and fourth partition portions 26, 27 and connects the inner ends of the third and fourth partition portions 26, 27 in the vehicle direction. The connecting portion 28 extends in the left-right direction and faces the inner surface of the upper member 22.

A battery case 30 is disposed on the inner side of the pair of side sills 10a, 10b in the vehicle width direction. This battery case 30 is a box that houses a battery module 40 inside, and in this embodiment, two battery modules are arranged inside the battery case 30 along the vehicle width direction. The battery module 40 is formed by stacking multiple battery cells.

As shown in FIG. 2, the battery case 30 has a storage section 31 and a lid section 32. The storage section 31 is a section that stores the battery module 40, and the battery module 40 is mounted on the bottom surface of the storage section 31. The storage section 31 has a box shape with an open top. The opening on the top surface of the storage section 31 is closed by the lid section 32.

The battery case 30 is supported by a bracket 50. The bracket 50 extends along the front-rear direction of the vehicle and is formed integrally with the battery case 30. The bracket 50 is connected to the underside of the side sill inner 12 via fastening bolts or the like.

As shown in Figures 1 and 2, a cross member 60 is disposed above the battery case 30. This cross member 60 is a member for reinforcing the vehicle body structure 1A in the area above the battery case 30 of the vehicle body structure 1A.

The cross member 60 is provided between the rear side member 20a and the rear side member 20b, and extends along the vehicle width direction. The cross member 60 is also disposed between the battery case 30 and the floor panel 70. Both ends of the cross member are connected to the outer surfaces of the lower members 21 of the rear side members 20a and 20b by welding or the like.

As shown in Figures 2 and 4, the cross member 60 has a U-shaped cross section with an opening at the top, and forms a closed cross section together with the floor panel 70 and the lower member 21 of the rear side member 20a. Note that, although the cross member 60 of this embodiment forms a closed cross section together with the floor panel 70 and the lower member 21 of the rear side member 20a, this is not limited thereto, and the cross member 60 alone may form a closed cross section. In this case, although not particularly limited thereto, the closed cross section may be formed by two steel plates, such as the side sills 10a, 10b and the rear side members 20a, 20b.

As shown in Figures 1 and 2, the floor panel 70 forms the floor of the vehicle interior. This floor panel 70 is disposed between the rear side members 20a, 20b, and is connected to the upper members 22 of the rear side members 20a, 20b by welding or the like.

With the vehicle body structure 1A described above, when a pole such as a utility pole collides with the side sills 10a, 10b on the side of the vehicle, the collision energy can be absorbed by both the bracket 50 and the cross member 60. This prevents the upper parts of the side sills 10a, 10b from deforming more than the lower parts as in the above-mentioned conventional technology, preventing the pole from entering the battery case 30 from above, thereby protecting the battery.

In addition, in this embodiment, the first bulkhead 15 is disposed inside the side sills 10a, 10b, so that the force applied to the side sills 10a, 10b can be efficiently transmitted to the rear side members 20a, 20b, and as a result, the cross member 60 can efficiently absorb the collision energy.

Similarly, in this embodiment, the second bulkhead 25 is disposed inside the rear side members 20a, 20b, so that the force transmitted from the side sills 10a, 10b can be efficiently transmitted from the rear side members 20a, 20b to the cross member 60, and as a result, the collision energy can be efficiently absorbed by the cross member 60.

Furthermore, with such a vehicle body structure 1A, the second bulkhead 25 and bracket 50 can be deformed during a side collision. In this case, by balancing the plate thickness, material, and structure (cross-sectional shape) of the second bulkhead 25 and bracket 50 so that the deformation capacity of the second bulkhead 25 and bracket 50 is the same, the pole penetrates the vehicle in a generally parallel manner in the vertical direction during a side collision, so that the deformation stroke of the second bulkhead 25 and bracket 50 can be maximized, and the loading capacity of the battery module 40 can be maximized.

The above-described embodiments are described to facilitate understanding of the present invention, and are not described to limit the present invention. Therefore, each element disclosed in the above embodiments is intended to include all design modifications and equivalents that fall within the technical scope of the present invention.

For example, in the above embodiment, the rear side members 20a, 20b are disposed inside the side sills 10a, 10b, but this is not limiting. As in the modified example shown in FIG. 5 below, the rear side members 20a, 20b may be disposed at the rear ends of the side sills 10a, 10b.

Figure 5 is a plan view showing a modified vehicle body structure according to this embodiment. In this modified example, the rear side members 20a, 20b are disposed at the rear ends of the side sills 10a, 10b, and the cross member 60 is connected to the side sill inner members 12 of the side sills 10a, 10b by welding or the like.

Even in this modified vehicle body structure 1B, when the pole collides with the side sills 10a, 10b on the side of the vehicle, the collision energy can be absorbed by both the bracket 50 and the cross member 60, and the battery can be protected.

DESCRIPTION OF SYMBOLS 1A, 1B...Vehicle body structure 10a, 10b...Side sill 11...Side sill outer 11a...Upper flange 11b...Lower flange 12...Side sill inner 12a...Upper flange 12b...Lower flange 15...First bulkhead 16...First partition portion 17...Second partition portion 18...Connecting portion 19...Interposition portion 20a, 20b...Rear side member 21...Lower member 22...Upper member 25...Second bulkhead 30...Battery case 31...Storage portion 32...Lid portion 40...Battery module 50...Bracket 60...Cross member 70...Floor panel

Claims (6)

A pair of side sills extending along a front-rear direction of the vehicle;
a battery case that houses a battery and is disposed between the pair of side sills;
a bracket disposed between the battery case and the pair of side sills and connecting the battery case and the pair of side sills;
A cross member is located above the battery case and extends along a width direction of the vehicle. The vehicle body structure according to claim 1,
The vehicle body structure includes a pair of first rear side members disposed between the pair of side sills and connected to the pair of side sills;
A vehicle body structure further comprising a first bulkhead disposed inside the first rear side member and extending along a vehicle width direction of the vehicle. The vehicle body structure according to claim 2,
A vehicle body structure in which both ends of the cross member are connected to the pair of first rear side members. The vehicle body structure according to claim 1,
The vehicle body structure further includes a pair of second rear side members connected to rear ends of the pair of side sills,
A vehicle body structure in which both ends of the cross member are connected to the pair of side sills. The vehicle body structure according to claim 1,
The vehicle body structure further includes a second bulkhead disposed inside the side sill and extending along a vehicle width direction of the vehicle. The vehicle body structure according to any one of claims 1 to 5,
The vehicle body structure further includes a floor panel that constitutes a floor portion of a vehicle compartment,
The cross member is a vehicle body structure provided between the floor panel and the battery case.

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