Vehicle lower part structure

Abstract

To obtain a vehicle lower part structure capable of maintaining crashworthiness at the time of a side collision even when the size of a battery is increased.SOLUTION: A vehicle lower part structure includes: a rocker 36 that is arranged on an outer side of a battery in the vehicle width direction and extends in the vehicle front-rear direction; a cross member 34 that is arranged above the battery and connects the rocker 36 in the vehicle width direction; and a lower load transmission member 42 that is arranged below the battery and extends in the vehicle width direction. At both ends of the lower load transmission member 42 in the vehicle width direction, a bent portion 42A bent in the vehicle up-down direction along the rocker 38 is formed, and the bent portion 42A and the rocker 38 are overlapped and fastened in the vehicle width direction by a fastening members 62.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] Patent Document 1 discloses a vehicle side structure in which an under-reinforcement is placed between a rocker and a battery case and the rocker and the under-reinforcement are connected by a cross member. In addition, the vehicle side structure described in Patent Document 1 has a crash box extending from the rocker toward the battery frame, thereby absorbing collision energy. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-104602 Summary of the Invention [Problem to be solved by the invention]

[0004] However, there is a trend toward larger batteries to increase vehicle range, and a known structure is one in which the battery extends close to the locking door. However, this structure does not allow for the placement of crash boxes, and there is room for improvement in maintaining crashworthiness in the event of a side collision.

[0005] An object of the present invention is to provide a vehicle underbody structure that can maintain crashworthiness in the event of a side collision even when a battery is enlarged. [Means for solving the problem]

[0006] The vehicle undercarriage structure of claim 1 comprises a rocker that is arranged outside the battery in the vehicle width direction and extends in the front-to-rear direction of the vehicle, a cross member that is arranged above the battery and connects the rocker in the vehicle width direction, and a lower load transmission member that is arranged below the battery and extends in the vehicle width direction, and both ends of the lower load transmission member in the vehicle width direction have bent portions that are bent in the vehicle up-down direction along the rocker, and the bent portions and the rocker are fastened together in the vehicle width direction by fastening members.

[0007] In the vehicle undercarriage structure according to claim 1, a rocker is disposed on the vehicle widthwise outer side of the battery, and the rocker extends in the vehicle front-rear direction. A cross member is disposed above the battery, and the cross member connects the rocker in the vehicle width direction. A lower load transmission member is disposed below the battery, and this lower load transmission member extends in the vehicle width direction. At both ends of the lower load transmission member in the vehicle width direction, a bent portion is formed that bends in the vehicle up-down direction along the rocker, and the bent portion and the rocker are overlapped and fastened in the vehicle width direction by fastening members. This allows a collision load to be transmitted from the rocker to the opposite side of the vehicle during a side collision (side impact) via the cross member and the lower load transmission member.

[0008] In particular, because the collision load can be distributed to the cross member and the lower load transmission member, the collision load can be transmitted more effectively than in a configuration in which the collision load is transmitted only above or below the battery. Furthermore, because the bent portion and the rocker are fastened together in the vehicle width direction by the fastening members, the collision load is transmitted in the axial direction of the fastening members, which allows the fastened state to be maintained better than in a configuration in which the collision load is transmitted in the shear direction of the fastening members.

[0009] A vehicle underbody structure according to a second aspect of the present invention is the vehicle underbody structure according to the first aspect, wherein the bent portion is bent downward along the rocker.

[0010] In the vehicle undercarriage structure of claim 2, the bent portion is bent toward the lower side of the vehicle, and therefore, compared to a configuration in which the bent portion is bent toward the upper side of the vehicle, the general portion of the lower load transmission member can be positioned upward, thereby reducing interference with the road surface.

[0011] A vehicle underbody structure according to a third aspect of the present invention is the vehicle underbody structure according to the first aspect, wherein the lower load transmitting member includes a panel member that extends in the vehicle width direction and the vehicle front-rear direction and covers the battery from below.

[0012] In the vehicle underbody structure according to claim 3, the panel member can protect the battery over a wide area from below the vehicle, and the panel member can distribute the collision load in the event of a side collision in the vehicle width direction and the vehicle front-rear direction.

[0013] The vehicle underbody structure according to claim 4 is the same as claim 3, wherein a reinforcing member is provided on the lower surface of the panel member, extending in the vehicle front-rear direction and forming a closed cross section between the panel member and the reinforcing member.

[0014] In the vehicle underbody structure according to claim 4, the panel member is reinforced by the reinforcing member, and therefore, buckling of the panel member can be suppressed when a collision load is input.

[0015] The vehicle undercarriage structure of claim 5 is any one of claims 1 to 4, in which a battery frame is arranged between the cross member and the rocker, the battery is fastened to the battery frame, and the battery frame is fastened to the rocker.

[0016] In the vehicle undercarriage structure according to claim 5, the battery frame and the rocker can be fastened together with the battery fastened to the battery frame, which improves work efficiency during vehicle assembly compared to a configuration in which the battery is fastened directly to the rocker. [Effects of the Invention]

[0017] As described above, the vehicle underbody structure according to the present invention can maintain crashworthiness in the event of a side collision even when the battery is enlarged. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a perspective view showing a part of a vehicle undercarriage according to an embodiment; [Figure 2] FIG. 2 is a cross-sectional view showing a state cut along line 2-2 in FIG. [Figure 3] FIG. 3 is an enlarged cross-sectional view showing the main part of FIG. 2 in an enlarged manner. DETAILED DESCRIPTION OF THE INVENTION

[0019] A vehicle underbody structure according to an embodiment will be described with reference to the drawings.

[0020] 1 is a perspective view showing a part of a vehicle undercarriage according to an embodiment. Note that the arrows FR, UP, and RH in the figure respectively indicate the vehicle forward direction, vehicle upward direction, and vehicle right direction of a vehicle 10 to which the vehicle undercarriage is applied. In the following description, unless otherwise specified, when the front-rear, up-down, and left-right directions are used, they refer to the front-rear direction of the vehicle, the up-down direction of the vehicle, and the left-right direction (width direction) of the vehicle, respectively.

[0021] 1, the vehicle undercarriage structure of this embodiment is configured to include a battery frame 12. The battery frame 12 is a substantially frame-shaped member that surrounds a battery case 20, and is disposed below a vehicle interior (not shown).

[0022] The battery frame 12 is configured to include a front frame 14, a rear frame 16, and a pair of left and right side frames 18. The front frame 14, the rear frame 16, and the side frames 18 may be integrally formed from metal, or may be formed separately. In this embodiment, as an example, the front frame 14, the rear frame 16, and the side frames 18 are each formed by extrusion molding to have a closed cross-sectional structure, and are joined together to form the battery frame 12.

[0023] The front frame 14 is located at the front of the vehicle undercarriage and extends in the vehicle width direction along the front end of the battery case 20. A front module (not shown) that constitutes the front of the vehicle is joined to the front frame 14.

[0024] The rear frame 16 is located at the rear of the vehicle undercarriage and extends in the vehicle width direction along the rear end of the battery case 20. A rear module (not shown) that constitutes the rear of the vehicle is joined to the rear frame 16.

[0025] The right end of the front frame 14 and the right end of the rear frame 16 are connected in the fore-and-aft direction of the vehicle by a side frame 18. In addition, the left end of the front frame 14 and the left end of the rear frame 16 are connected in the fore-and-aft direction of the vehicle by the side frame 18.

[0026] A pair of left and right side frames 18 each extend in the longitudinal direction of the vehicle outside the vehicle width direction of the battery case 20, with the front ends of the side frames 18 connected to the front frame 14 and the rear ends of the side frames 18 connected to the rear frame 16.

[0027] Figure 2 is an enlarged cross-sectional view of a main part taken along line 2-2 in Figure 1. As shown in Figure 2, the battery case 20 includes an upper case 22 and a lower case 24, and a battery is housed inside the battery case 20.

[0028] The upper case 22 is formed in a roughly hat shape with the lower side of the vehicle open when viewed in cross section from the front-to-rear direction of the vehicle, and upper flanges 22A are formed at both ends of the upper case 22 in the vehicle width direction, and are superimposed on the undersides of the left and right side frames 18.

[0029] The lower case 24 is formed in a generally hat shape with an open upper side in a cross section seen from the vehicle front-rear direction, and lower flanges 24A are formed at both ends of the lower case 24 in the vehicle width direction, overlapping with upper flanges 22A of the upper case 22. The upper flanges 22A and the lower flanges 24A are mechanically fastened to the side frames 18.

[0030] In this embodiment, as an example, no floor panel is provided, and the upper case 22 of the battery case 20 forms the floor surface of the vehicle compartment. However, this is not limited to this, and a floor panel may be provided on the vehicle upper side of the upper case 22.

[0031] Cross members 34 are installed between the left and right side frames 18 that make up the battery frame 12. As shown in Fig. 1, in this embodiment, as an example, two cross members 34 are provided in the front-rear direction of the vehicle, and each extends in the vehicle width direction.

[0032] As shown in Fig. 2, both ends of the cross member 34 in the vehicle width direction are bent toward the upper side of the vehicle along the side frames 18 and fixed to the side frames 18. The method for fixing the cross member 34 to the side frames 18 is not particularly limited, and the cross member 34 may be mechanically fastened using bolts and nuts, or may be joined by welding, etc. Furthermore, the cross member 34 may be joined using an adhesive, a pressure-sensitive adhesive, or a combination of these methods.

[0033] Rockers 36 are arranged on the outer side of the battery case 20 in the vehicle width direction. A pair of rockers 36 are provided on the left and right, and each is a frame member extending in the front-to-rear direction of the vehicle. The rockers 36 are configured to include a rocker outer panel 38 arranged on the outer side in the vehicle width direction and a rocker inner panel 40 arranged on the inner side in the vehicle width direction.

[0034] The rocker outer panel 38 is formed in a roughly hat shape with the inner side in the vehicle width direction open when viewed in cross section from the vehicle's fore-and-aft direction, and outer flanges 38A extending in the vehicle's vertical direction are formed on both the upper and lower ends.

[0035] The rocker inner panel 40 is formed in a generally flat plate shape with its thickness direction aligned with the vehicle width direction, and inner flanges 40A are formed at the upper and lower ends of the rocker inner panel 40, overlapping the outer flange 38A of the rocker outer panel 38. The outer flange 38A and the inner flange 40A are joined in an overlapping state by welding or the like. Note that an energy absorbing material or the like may be disposed within the closed cross section formed by the rocker outer panel 38 and the rocker inner panel 40.

[0036] Here, the rocker inner panel 40 abuts against the outer surfaces of the side frames 18 of the battery frame 12 in the vehicle width direction, and the rocker outer panel 38 is mechanically fastened to the side frames 18. In this way, by fixing the rockers 36 to the side frames 18, the left and right rockers 36 are connected in the vehicle width direction by the cross members 34.

[0037] A panel member 42 serving as a lower load transmission member is provided on the vehicle lower side of the battery case 20. The panel member 42 extends in the vehicle width direction and the vehicle front-rear direction, and connects the left and right rockers 36 in the vehicle width direction. The panel member 42 is formed in a generally flat plate shape so as to cover the battery case 20 from the vehicle lower side. Here, a plurality of reinforcing members 44 are provided on the lower surface of the panel member 42.

[0038] Each of the reinforcing members 44 extends in the vehicle longitudinal direction and has a generally hat-shaped cross section that is open toward the upper side of the vehicle when viewed from the vehicle longitudinal direction. A closed cross section is formed between the panel member 42 and the reinforcing member 44. In this embodiment, as an example, the reinforcing members 44 are arranged at equal intervals in the vehicle width direction.

[0039] Next, with reference to FIG. 3, the fastening structure of the battery case 20, the battery frame 12, the rocker 36, and the panel member 42 will be described.

[0040] Fig. 3 is an enlarged cross-sectional view of a main part of Fig. 2. As shown in Fig. 3, the battery case 20 and the battery frame 12 are mechanically fastened together by a first bolt 50 and a first nut 52. Specifically, the first bolt 50 is inserted from the lower side of the battery case 20 and is screwed into the first nut 52 inside the battery frame 12. Note that the first bolt 50 may be a weld nut welded to the battery frame 12 in advance, or may be attached through an access hole (not shown) formed in the battery frame 12.

[0041] The battery frame 12 and the rocker 36 are mechanically fastened together by a second bolt 54, a third bolt 58, a second nut 56, and a third nut 60. Specifically, the upper part of the battery frame 12 and the rocker inner panel 40 are mechanically fastened together by the second bolt 54 and the second nut 56, and the lower part of the battery frame 12 and the rocker inner panel 40 are mechanically fastened together by the third bolt 58 and the third nut 60. The second bolt 54 and the second bolt 54 are inserted into the rocker inner panel 40 and the battery frame 12 through working holes (not shown) formed in the rocker outer panel 38, and are screwed into the second nut 56 and the third nut 60, respectively.

[0042] The panel member 42 and the rocker 36 are mechanically fastened by a fourth bolt 62 and a fourth nut 64. Specifically, a bent portion 42A that is bent toward the vehicle lower side along the rocker 36 is formed at both ends of the panel member 42 in the vehicle width direction, and the bent portion 42A and the rocker 36 are fastened in the vehicle width direction by the fourth bolt 62 and the fourth nut 64 while overlapping each other. Therefore, the three members, namely the rocker outer panel 38, the rocker inner panel 40, and the bent portion 42A, are mechanically fastened by the fourth bolt 62 and the fourth nut 64. Note that, as an example, in the present embodiment, the fourth bolt 62 is inserted from the outer side in the vehicle width direction, but this is not limited thereto, and the fourth bolt 62 may be inserted from the inner side in the vehicle width direction. In this case, the fourth nut 64 is disposed on the rocker outer panel 38 side.

[0043] (action) Next, the operation of the vehicle underbody structure according to this embodiment will be described.

[0044] In the vehicle undercarriage structure according to this embodiment, a rocker 36 is disposed on the outer side of the battery case 20 in the vehicle width direction, and the rocker 36 extends in the vehicle front-rear direction. A cross member 34 is disposed above the battery case 20, and the cross member 34 connects the rocker 36 in the vehicle width direction via the battery frame 12. A panel member 42 is disposed below the battery, and extends in the vehicle width direction. Bend portions 42A that bend in the vehicle up-down direction along the rocker 36 are formed at both ends of the panel member 42 in the vehicle width direction. The bend portions 42A and the rocker 36 are overlapped and fastened in the vehicle width direction by a fourth bolt 62 and a fourth nut 64, which are fastening members. This allows a collision load to be transmitted from the rocker 36 to the opposite side of the vehicle in a side collision via the cross member 34 and the panel member 42.

[0045] In particular, the cross member 34 and the panel member 42 can distribute the collision load above and below the battery frame 12, allowing the collision load to be transmitted more effectively than in a configuration in which the collision load is transmitted only to one of the upper and lower parts of the battery case 20. Furthermore, because the bent portion 42A and the rocker 36 are fastened together in the vehicle width direction by the fourth bolt 62 and the fourth nut 64, the collision load is transmitted in the axial direction of the fourth bolt 62, allowing the fastened state to be maintained more favorably than in a configuration in which the collision load is transmitted in the shear direction of the bolt. As a result, collision resistance in a side collision can be maintained even when the battery is enlarged.

[0046] Furthermore, in the vehicle undercarriage structure according to this embodiment, because the bent portion 42A is bent downward toward the vehicle, the general portion of the panel member 42 can be positioned higher, and interference with the road surface can be reduced, compared to a configuration in which the bent portion 42A is bent upward toward the vehicle. That is, when the bent portion bent from the general portion of the panel member toward the vehicle upper side is fastened to the rocker, the height of the general portion of the panel member is approximately the same as the height of the lower end of the rocker, which may cause interference with obstacles such as fallen objects on the road surface. In contrast, in this embodiment, a wide gap can be secured between the general portion of the panel member 42, excluding the bent portion 42A, and the road surface, thereby reducing interference with obstacles on the road surface.

[0047] Furthermore, in this embodiment, the battery case 20 can be widely protected from the underside of the vehicle by the panel member 42. Also, the panel member 42 can distribute the collision load in the event of a side collision in the vehicle width direction and the vehicle front-rear direction.

[0048] Furthermore, in this embodiment, as shown in FIG. 2, the panel member 42 is reinforced by the reinforcing member 44, which can prevent the panel member 42 from buckling when a collision load is input.

[0049] Furthermore, in this embodiment, the structure allows the battery frame 12 and the rocker 36 to be fastened together while the battery case 20 is fastened to the battery frame 12, thereby improving work efficiency when assembling the vehicle compared to a configuration in which the battery case 20 is fastened directly to the rocker 36.

[0050] Although the vehicle undercarriage structure according to the embodiment has been described above, it is needless to say that it can be embodied in various forms without departing from the spirit and scope of the present invention. For example, in the above embodiment, the rocker 36 and the battery frame 12 are fastened together by two bolts, the second bolt 54 and the third bolt 58, but this is not limited thereto. For example, they may be fastened together by a single bolt in the vertical direction.

[0051] In the above embodiment, the bent portion 42A is formed by bending it downwardly of the vehicle, but this is not limited thereto, and it may be bent upwardly of the vehicle. Furthermore, a substantially belt-shaped lower load transmission member may be provided instead of the panel member 42 of the above embodiment.

[0052] The following notes are provided regarding the above embodiment.

[0053] (Appendix 1) a rocker disposed on the outer side of the battery in the vehicle width direction and extending in the vehicle front-rear direction; a cross member disposed above the battery and connecting the rockers in the vehicle width direction; a lower load transmission member disposed below the battery and extending in the vehicle width direction; and a bent portion bent in the vehicle up-down direction along the rocker is formed at both end portions of the lower load transmission member in the vehicle width direction, The bent portion and the rocker are fastened together in the vehicle width direction by a fastening member in an overlapping state. Vehicle undercarriage. (Appendix 2) 2. The vehicle undercarriage structure according to claim 1, wherein the bent portion is bent downwardly along the rocker. (Appendix 3) 3. The vehicle undercarriage structure according to claim 1, wherein the lower load transmission member includes a panel member extending in the vehicle width direction and the vehicle front-rear direction and covering the battery from below. (Appendix 4) 4. A vehicle undercarriage structure as described in Appendix 3, wherein a reinforcing member extending in the vehicle fore-and-aft direction and forming a closed cross section between the panel member and the reinforcing member is provided on the underside of the panel member. (Appendix 5) A battery frame is disposed between the cross member and the rocker, the battery is fastened to the battery frame, 5. The vehicle underbody structure according to any one of claims 1 to 4, wherein the battery frame is fastened to the rocker. [Explanation of symbols]

[0054] 12 Battery Frame 20 Battery case (battery) 34 Cross member 38 Rocca 42 Panel member (lower load transmission member) 42A Bend part 44 Reinforcement member 62 Fourth bolt (fastening member) 64 Fourth nut (fastening member)

Claims

1. a rocker disposed on the outer side of the battery in the vehicle width direction and extending in the vehicle front-rear direction; a cross member disposed above the battery and connecting the rockers in the vehicle width direction; a lower load transmission member disposed below the battery and extending in the vehicle width direction; and a bent portion bent in the vehicle up-down direction along the rocker is formed at both end portions of the lower load transmission member in the vehicle width direction, The bent portion and the rocker are fastened together in the vehicle width direction by a fastening member in an overlapping state. Vehicle undercarriage.

2. The vehicle underbody structure according to claim 1 , wherein the bent portion is bent downward along the rocker.

3. 2. The vehicle underbody structure according to claim 1, wherein the lower load transmission member includes a panel member that extends in the vehicle width direction and the vehicle front-rear direction and covers the battery from below.

4. The vehicle underbody structure according to claim 3, wherein a reinforcing member is provided on the underside of the panel member, the reinforcing member extending in the vehicle longitudinal direction and defining a closed cross section between the panel member and the reinforcing member.

5. A battery frame is disposed between the cross member and the rocker, the battery is fastened to the battery frame, 5. The vehicle underbody structure according to claim 1, wherein the battery frame is fastened to the rocker.

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