Lower vehicle body structure of vehicle

Abstract

The purpose of the present invention is to provide a lower vehicle body structure for a vehicle, which can improve the energy absorption amount of a side member during a lateral collision of the vehicle and can improve the rigidity of the side member during normal travel. A lower vehicle body structure of a vehicle is provided with an outer reinforcement member (13) and an inner reinforcement member (14) inside a side member (2). Ridge lines (11f, 11g) extending in the front-rear direction (X) are respectively formed between an outer vertical wall part (11a) and an outer top plate part (11b) and between the outer vertical wall part (11a) and an outer bottom plate part (11c) of the side beam (2). The inner reinforcement member (14) is fixed to the inner vertical wall section (12a) and has a section (15) to be fitted to the outer reinforcement member (13) during a lateral collision of the vehicle. The outer reinforcement member (13) has a fitting section (18) that fits into the fitting section (15), and bracket sections (17a, 17b) that connect at least one of the outer vertical wall section (11a) and the outer top plate section (11b) and the outer vertical wall section (11a) and the outer bottom plate section (11c) across ridge lines (11f, 11g).

Description

Technical Field

[0001] The present invention relates to a lower body structure of a vehicle. Background Art

[0002] There are various known techniques that, when a vehicle collides with an obstacle such as a pillar from the side of the vehicle, i.e., in a vehicle side collision, crush a side sill that forms the lower part of the vehicle side to absorb the energy during the collision. Especially in an electric vehicle, a battery pack is arranged under the floor of the vehicle. Therefore, from the viewpoint of protecting the battery pack, it is particularly important to improve the energy absorption performance in the side sill.

[0003] In the structure described in Patent Document 1, in order to increase the energy absorption amount of the side sill, an outer reinforcing member and an inner reinforcing member are provided inside the closed cross-section of the side sill. In this structure, the outer reinforcing member is fixed to the longitudinal wall portion of the outer side beam, which is the vehicle outer side portion of the side sill. Similarly, the inner reinforcing member is fixed to the longitudinal wall portion of the inner side beam, which is the vehicle inner side portion of the side sill. The outer reinforcing member and the inner reinforcing member are in a contact state inside the closed cross-section of the side sill.

[0004]

Prior Art Documents

Patent Documents

Patent Document 1

[0005]

Technical Problem to be Solved by the Invention

[0006] Therefore, during a vehicle side collision, due to the angular displacement at the ridge line of the outer side beam, the outer reinforcing member deviates in the vertical direction, making it difficult to stably fit the outer reinforcing member and the inner reinforcing member. Therefore, there is a problem that it is difficult to increase the energy absorption amount of the outer reinforcing member and the inner reinforcing member.

[0007] In addition, in the above structure, even during normal driving, the outer reinforcing member fixed to the longitudinal wall alone cannot suppress the angular displacement at the ridge line on the cabin side of the side sill. Therefore, there is a problem that it is difficult to increase the rigidity of the side sill.

[0008] Moreover, since the outer reinforcing member and the inner reinforcing member are in a contact state inside the closed cross-section of the side sill, during normal driving, along with the minute angular displacement of the side sill, the outer reinforcing member moves up and down, which may cause abnormal noise.

[0009] In view of the above circumstances, an object of the present invention is to provide a lower body structure of a vehicle that can increase the energy absorption amount of side beams during a vehicle side collision and can increase the rigidity of side beams during normal driving.

[0010]

Technical means for solving technical problems

[0011] In the above structure, an outer reinforcing member and an inner reinforcing member are provided inside the side beams. Moreover, the outer reinforcing member has: a fitting portion that fits with the fitting portion of the inner reinforcing member when a vehicle side collision occurs, that is, when an impact load from the vehicle side is input to the side beams, and has a bracket portion. The bracket portion straddles the ridge line of the side beams and connects at least one of between the outer longitudinal wall portion and the outer top plate portion and between the outer longitudinal wall portion and the outer bottom plate portion.

[0012] In this structure, the angular displacement of the ridge line (such as the displacement of the angular part of the closed cross-section opening or closing, etc.) can be suppressed by the bracket portion. Therefore, during a vehicle side collision, the fitting portion of the outer reinforcing member is difficult to deviate in the up and down directions, and the fitting portion of the outer reinforcing member can be stably fitted with the fitting portion of the inner reinforcing member, enabling the outer reinforcing member and the inner reinforcing member to be sufficiently compressed and deformed. Thereby, the energy absorption amount can be increased.

[0013] In addition, during normal driving, the angular displacement of the ridge line can be suppressed by the bracket portion, and the body rigidity can also be increased.

[0014] Moreover, even if the outer reinforcing member and the inner reinforcing member are set to be in contact within the closed cross-section of the side beam, during normal driving, there will be no minor angular displacement of the side beam, nor will there be an accompanying up-and-down movement of the outer reinforcing member, so no abnormal noise will be generated.

[0015] Preferably, in the lower body structure of the above vehicle, one of the fitting portion and the fitted portion has a convex cross-section and extends in the front-rear direction, and the other has a concave cross-section corresponding to the convex cross-section and extends in the front-rear direction.

[0016] In the related structure, through the fitting of the recessed portion (i.e., groove) and the convex portion (i.e., rib) that extend in the front-rear direction respectively, the fitting portion and the fitted portion can be stably fitted. In addition, by roll-forming the metal sheet, one of the fitting portion and the fitted portion can be continuously formed into a shape with a convex cross-section and extending in the front-rear direction, and the other can be continuously formed into a shape with a concave cross-section and extending in the front-rear direction, and a shape that can achieve stable fitting can be easily formed.

[0017] Preferably, in the lower body structure of the above vehicle, the outer reinforcing member includes a first portion having the fitting portion and a second portion connected to the first portion and having the bracket portion.

[0018] According to the related structure, the first portion having the fitting portion and the second portion having the bracket portion can be separately roll-formed from the metal sheet to be continuously formed into the desired cross-sectional shape. Then, the formed first portion and the second portion are connected, whereby an outer reinforcing member having a fitting portion and a bracket portion can be easily manufactured.

[0019] Preferably, in the lower body structure of the above vehicle, the first portion is fixed to the side beam via the second portion.

[0020] According to the related structure, in the outer reinforcing member, the collision load input to the side beam during a side collision of the vehicle can be effectively transmitted from the second portion to the first portion. Thus, the load can be smoothly transmitted from the bracket portion of the second portion to the fitting portion of the first portion.

[0021] Preferably, in the lower body structure of the above vehicle, the first portion has an upper wall portion connecting the fitting portion and the second portion, and a lower wall portion located below the upper wall portion and connecting the fitting portion and the second portion, and the upper wall portion and the lower wall portion have a deformation promoting portion that partially promotes deformation during a side collision of the vehicle.

[0022] According to the related structure, during a side collision of the vehicle, in the first part of the outer reinforcing member, the fitting portion fits with the fitted portion of the inner reinforcing member during a side collision of the vehicle, and deformation is partially promoted in the deformation promoting portions of the upper wall portion and the lower wall portion, thereby further increasing the amount of energy absorption in the outer reinforcing member.

[0023] Preferably, in the lower body structure of the above vehicle, the first part is made of a sheet material, the deformation promoting portion is composed of a plurality of stepped portions, and the plurality of stepped portions are formed by partially bending and deforming the sheet material.

[0024] In the related structure, the deformation promoting portion is composed of a plurality of stepped portions, whereby the deformation promoting portion can be formed in a simple structure on the upper wall portion and the lower wall portion of the first part of the outer reinforcing member. During a side collision of the vehicle, folding deformation (so-called bellows-like deformation) occurs at the plurality of stepped portions, whereby the first part of the outer reinforcing member can be easily deformed. At the same time, the amount of energy absorption in the outer reinforcing member can be easily set or controlled by the stepped shape of the first part.

[0025] Preferably, in the lower body structure of the above vehicle, the bracket portion connects the outer longitudinal wall portion and the outer roof plate portion of the side beam across the ridge line and connects the outer longitudinal wall portion and the outer floor plate portion.

[0026] In the related structure, the bracket portion connects the outer roof plate portion, the outer longitudinal wall portion, and the outer floor plate portion of the side beam across two ridge lines formed between the outer roof plate portion, the outer longitudinal wall portion, and the outer floor plate portion of the side beam, so that the amount of energy absorption of the side beam during a side collision of the vehicle can be further increased, and the rigidity of the side beam during normal driving can be further increased.

[0027] Preferably, in the lower body structure of the above vehicle, the outer longitudinal wall portion has reinforcing ribs extending in the front-rear direction, and the bracket portion is fixed to the reinforcing ribs.

[0028] According to the related structure, the outer longitudinal wall portion of the side beam has reinforcing ribs extending in the front-rear direction, thereby increasing the rigidity of the outer longitudinal wall portion. And the bracket portion is fixed to the reinforcing ribs with high rigidity in the outer longitudinal wall portion, whereby the impact load during a side collision of the vehicle can be smoothly transmitted from the outer longitudinal wall portion of the side beam to the bracket portion of the outer reinforcing member, and the amount of energy absorption in the outer reinforcing member can be further increased.

[0029] Preferably, in the lower body structure of the above vehicle, the inner reinforcing member and the outer reinforcing member are formed by roll-forming a metal sheet.

[0030] According to the related structure, the inner reinforcing member and the outer reinforcing member are formed by roll-forming a metal sheet, so that they can be continuously formed into a desired cross-sectional shape easily and inexpensively. Moreover, since the inner reinforcing member and the outer reinforcing member are continuously formed by roll-forming, they can be applied to vehicles of various overall vehicle lengths, that is, they can adapt to changes in vehicle size.

[0031] Furthermore, the inner reinforcing member and the outer reinforcing member that are continuously formed by roll-forming reinforce the side beam in a relatively long section in the front-rear direction, so that a high energy absorption amount can be obtained regardless of which section in the front-rear direction of the side beam collides with an obstacle.

[0032] Preferably, in the lower body structure of the above vehicle, there is also a cross beam extending in the vehicle width direction, and the cross beam is connected to the inner longitudinal wall portion of the side beam in the vertical direction within a range including the overlapping portion of the inner reinforcing member and the side beam.

[0033] According to the related structure, during a side collision of the vehicle, the cross beam can support the overlapping portion of the inner reinforcing member and the side beam from the inside of the vehicle and effectively bear the collision load at the same time. Thereby, the energy absorption amount in the side beam and the inner reinforcing member can be further increased.

[0034]

Advantages of the Invention

[0035] Figure 1 is a perspective view of the overall structure of a body applicable to the lower body structure of a vehicle according to an embodiment of the present invention; Figure 2 is Figure 1 a left view of the body; Figure 3 is Figure 2 a sectional view taken along line III-III of, and is a sectional view showing an outer reinforcing member having a fitting portion with a relatively large convex cross section and an inner reinforcing member having a fitted portion with a relatively large concave cross section; Figure 4 shows a sectional view of an outer reinforcing member having a fitting portion with a relatively small convex cross section and an inner reinforcing member having a fitted portion with a relatively small concave cross section as a modification example of the present invention; Figure 5 shows a sectional view of an outer reinforcing member having a fitting portion with a relatively small concave cross section and an inner reinforcing member having a fitted portion and having two relatively small convex portions in the cross section of the fitted portion as another modification example of the present invention; Figure 6Figures (a) to (d) show the cross-sectional views of the crushing process of the side beams and the outer and inner reinforcing members inside them according to the present embodiment during a side collision of a vehicle. Figure 3 Figures (a) to (d) show the cross-sectional views of the crushing process of the side beams and the outer and inner reinforcing members inside them according to the comparative example during a side collision of a vehicle. In the structure of the comparative example, the outer and inner reinforcing members do not have fitting portions and fitted portions. Figure 7 Figures (a) to (d) show the cross-sectional views of the crushing process of the side beams and the outer and inner reinforcing members inside them according to the comparative example during a side collision of a vehicle. In the structure of the comparative example, the outer and inner reinforcing members do not have fitting portions and fitted portions. Figure 8 represents a comparative example Figure 7 and shows the cross-sectional view of the spot welds of two layers in the side beams and the outer and inner reinforcing members inside them. Figure 9 represents another comparative example of an existing structure and shows the cross-sectional view of the spot welds of two layers and three layers in the side beams, the outer and inner reinforcing members, and the partition members inside them. Detailed Embodiment

[0036] Hereinafter, the lower body structure of a vehicle according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0037] As Figures 1 - 2 shown, a vehicle body 1 to which the lower body structure of a vehicle according to an embodiment of the present invention is applied includes side beams 2 that form the side lower portions of the vehicle body 1 on both sides in the vehicle width direction Y. In the following drawings, arrow X represents the vehicle front-rear direction, arrow Y represents the vehicle width direction, and arrow Z represents the vertical direction.

[0038] Specifically, the vehicle body 1 includes: a pair of side beams 2 extending in the vehicle front-rear direction X, front pillars 3 (A pillars) extending upward from the front end portions of the side beams 2 on the vehicle front side, central pillars 4 (B pillars) extending upward at intermediate positions in the front-rear direction X of the side beams 2, rear pillars 5 (C pillars) extending upward from the vicinity of the rear end portions of the side beams 2 on the vehicle rear side, a roof rail 10 extending in the front-rear direction X and connecting the upper end portions of these three pillars 3 to 5, and four cross members 6 to 9 (first cross member 6, front intermediate cross member 7, second cross member 8, and third cross member 9) extending in the vehicle width direction Y between the pair of side beams 2 and connected to the side beams 2.

[0039] The side beams 2, the three pillars 3 to 5, and the roof rail 10 form a part of the vehicle frame on both sides in the vehicle width direction.

[0040] The four cross members 6 to 9 are separately arranged in the front-rear direction X. As Figure 3As shown in the front middle cross member 7, the four cross members 6 to 9 are connected to the inner longitudinal wall portion 12a of the inner beam 12 in the up-and-down direction Z within a range including the overlapping portion of the inner reinforcing member 14 and the side beam 2 described later. And the first cross member 6 and the second cross member 8 are respectively connected to the side beam 2 in the front-and-rear direction X within a range of the portions where the front pillar 3 and the center pillar 4 are connected to the side beam 2.

[0041] As Figure 3 shown, inside the side beam 2, two reinforcing members, namely, the outer reinforcing member 13 and the inner reinforcing member 14, are fixed to the inner side surface of the side beam 2. The outer reinforcing member 13 and the inner reinforcing member 14 are respectively arranged inside the side beam 2 and extend in the front-and-rear direction X. Compared with the outer reinforcing member 13, the inner reinforcing member 14 is arranged on the vehicle inner side in the vehicle width direction Y, that is, arranged in the vehicle width direction inner side Y2.

[0042] Hereinafter, the structure of the side beam 2 and the outer reinforcing member 13 and the inner reinforcing member 14 inside it will be further described in detail.

[0043] (Description of the side beam 2) As Figure 3 shown, the side beam 2 is a hollow cylinder extending in the vehicle front-and-rear direction X. The side beam 2 is composed of two hat-shaped members, namely, including the outer beam 11 and the inner beam 12. The side beam 2 has a closed cross-section C with a substantially rectangular cross-section. The side beam 2 is manufactured by joining the upper and lower paired flange portions 11d, 11e of the outer beam 11 and the upper and lower paired flange portions 12d, 12e of the inner beam 12 to each other.

[0044] The outer beam 11 has an outer longitudinal wall portion 11a, an outer top plate portion 11b, an outer bottom plate portion 11c, an upper flange portion 11d, and a lower flange portion 11e.

[0045] The outer longitudinal wall portion 11a is a flat plate portion facing the outer side in the vehicle width direction Y and extends in the vehicle front-and-rear direction X. The outer top plate portion 11b is a flat plate portion facing upward, and one end (the end on the vehicle width direction outer side Y1) thereof is connected to the upper end of the outer longitudinal wall portion 11a. The outer bottom plate portion 11c is a flat plate portion facing downward, and one end (the end on the vehicle width direction outer side Y1) thereof is connected to the lower end of the outer longitudinal wall portion 11a. The outer top plate portion 11b and the outer bottom plate portion 11c respectively extend substantially in the horizontal direction and are slightly inclined in the direction of moving away from each other as they approach the inner beam 12.

[0046] The upper flange portion 11d is a flat plate portion extending upward from the other end (the end on the vehicle width direction inner side Y2) of the outer top plate portion 11b. The lower flange portion 11e is a flat plate portion extending downward from the other end (the end on the vehicle width direction inner side Y2) of the outer bottom plate portion 11c.

[0047] Between the outer longitudinal wall portion 11a and the outer top plate portion 11b and between the outer longitudinal wall portion 11a and the outer bottom plate portion 11c, ridge lines 11f, 11g extending in the front-rear direction X are respectively formed (i.e., the corners on the outer side Y1 in the vehicle width direction in the closed cross-section C). That is, the ridge line 11f (in other words, the upper ridge line 11f or the first ridge line 11f) is formed between the outer longitudinal wall portion 11a and the outer top plate portion 11b. On the other hand, the ridge line 11g (in other words, the lower ridge line 11g or the second ridge line 11g) is formed between the outer longitudinal wall portion 11a and the outer bottom plate portion 11c and is disposed below the ridge line 11f.

[0048] The outer longitudinal wall portion 11a has a reinforcing rib 11h extending in the front-rear direction X ( Figure 3 a concave portion recessed toward the inner side Y2 in the vehicle width direction).

[0049] The inner beam 12 is disposed on the inner side Y2 in the vehicle width direction of the outer beam 11. The inner beam 12 has an inner longitudinal wall portion 12a, an inner top plate portion 12b, an inner bottom plate portion 12c, an upper flange portion 12d, and a lower flange portion 12e.

[0050] The inner longitudinal wall portion 12a is a flat plate-like portion located on the vehicle inner side relative to the above-mentioned outer longitudinal wall portion 11a and facing the inner side in the vehicle width direction Y, and extends in the vehicle front-rear direction X. The inner top plate portion 12b is a flat plate-like portion facing upward, and one end (the end on the inner side Y2 in the vehicle width direction) thereof is connected to the upper end of the inner longitudinal wall portion 12a. The inner bottom plate portion 12c is a flat plate-like portion facing downward, and one end (the end on the inner side Y2 in the vehicle width direction) thereof is connected to the lower end of the inner longitudinal wall portion 12a. The inner top plate portion 12b and the inner bottom plate portion 12c respectively extend substantially in the horizontal direction and are slightly inclined away from each other as they approach the outer beam 11.

[0051] The upper flange portion 12d is a flat plate-like portion extending upward from the other end (the end on the outer side Y1 in the vehicle width direction) of the inner top plate portion 12b. The lower flange portion 12e is a flat plate-like portion extending downward from the other end (the end on the outer side Y1 in the vehicle width direction) of the inner bottom plate portion 12c.

[0052] Between the inner longitudinal wall portion 12a and the inner top plate portion 12b and between the inner longitudinal wall portion 12a and the inner bottom plate portion 12c, ridge lines 12f, 12g extending in the front-rear direction X are respectively formed (i.e., the corners on the inner side Y2 in the vehicle width direction in the closed cross-section C).

[0053] The closed cross-section C of the side beam 2 is formed into a substantially rectangular shape by the above six flat plate-like portions, namely, the outer longitudinal wall portion 11a, the inner longitudinal wall portion 12a, the outer top plate portion 11b, the outer bottom plate portion 11c, the inner top plate portion 12b, and the inner bottom plate portion 12c. Therefore, the outer longitudinal wall portion 11a, the inner longitudinal wall portion 12a, the outer top plate portion 11b, and the outer bottom plate portion 11c form a part of the closed cross-section C. If the inner longitudinal wall portion 12a of the inner side beam 12 has a bent structure with a semi-circular cross-section, the inner top plate portion 12b and the inner bottom plate portion 12c may not be provided.

[0054] (Description of the outer reinforcing member 13 and the inner reinforcing member 14) Figure 3 The illustrated inner reinforcing member 14 and outer reinforcing member 13 are formed by roll-forming a metal plate. Roll-forming is a forming method in which a plate is fed between a pair or a plurality of pairs of rollers and compressed from both sides, thereby continuously forming a desired cross-sectional shape.

[0055] Figure 3 The illustrated inner reinforcing member 14 is fixed to the inner longitudinal wall portion 12a and has a fitting portion 15 that fits with the fitting portion 18 of the outer reinforcing member 13 when an impact load from the side of the vehicle is input to the side beam 2. Details of the fitting portion 15 will be described in the following section.

[0056] The cross-section of the inner reinforcing member 14 is in the shape of a cap. Specifically, it has: a main body portion 14a with a substantially U-shaped cross-section having the fitting portion 15, an upper flange portion 14b that extends upward from the end of the upper wall portion of the main body portion 14a and joins the inner longitudinal wall portion 12a and the inner top plate portion 12b of the inner side beam 12, and a lower flange portion 14c that extends downward from the end of the lower wall portion of the main body portion 14a and joins the inner longitudinal wall portion 12a and the inner bottom plate portion 12c of the inner side beam 12.

[0057] The upper flange portion 14b and the lower flange portion 14c of the inner reinforcing member 14 are joined to the inner longitudinal wall portion 12a, the inner top plate portion 12b, and the inner bottom plate portion 12c of the inner side beam 12 by spot welding or the like, thereby being able to suppress angular displacement of the ridges 12f, 12g (corners) of the inner side beam 12.

[0058] The outer reinforcing member 13 may have a structure with a fitting portion 18 that fits with the fitting portion 15 of the inner reinforcing member 14 and bracket portions 17a, 17b.

[0059] Specifically, Figure 3The shown outer reinforcing member 13 includes a first part 16 having a fitting portion 18 and a second part 17 connected to the first part 16 and having bracket portions 17a, 17b. The first part 16 and the second part 17 are respectively formed individually by roll forming of a metal sheet, and are joined to each other by welding or the like after forming. The first part 16 is fixed to the outer beam 11 via the second part 17.

[0060] Specifically, the first part 16 has: a front end face 16a extending in the vertical direction Z as the main part of the fitting portion 18, an upper wall portion 16b connecting the upper end of the front end face 16a to the bracket portions 17a, 17b of the second part 17, and a lower wall portion 16c located below the upper wall portion 16b and connecting the lower end of the front end face 16a to the bracket portions 17a, 17b of the second part 17.

[0061] The upper wall portion 16b and the lower wall portion 16c have stepped portions 16f, 16g as deformation promoting portions that partially promote deformation during a lateral collision of the vehicle.

[0062] Figure 3 The shown first part 16 is made of a sheet material. In Figure 3 the example, the deformation promoting portion is composed of a plurality of stepped portions 16f, 16g formed by partially bending and deforming (zigzagging or bending) the sheet material. Figure 3 The shown stepped portions 16f, 16g are reinforcing ribs or uneven portions extending in the front-rear direction X.

[0063] Hereinafter, the fitting portion 18 and the fitted portion 15 will be described in detail.

[0064] (Description of the fitting portion 18 and the fitted portion 15) When an impact load from the side of the vehicle is input to the side beam 2, the fitting portion 18 is fitted to the fitted portion 15 of the inner reinforcing member 14. Figure 3 The shown fitting portion 18 is separated from the fitted portion 15 before the collision load is input during a lateral collision of the vehicle, but may also be in contact with the fitted portion 15.

[0065] It is sufficient that one of the fitting portion 18 and the fitted portion 15 has a convex cross-section and extends in the front-rear direction X, and the other has a concave cross-section corresponding to the convex cross-section and extends in the front-rear direction X.

[0066] For example, in Figure 3In the fitting portion 18 and the fitted portion 15, a fitting portion 18 with a relatively large convex shape is formed by the front end face 16a of the first portion 16 of the outer reinforcing member 13 and the portions of the upper wall portion 16b and the lower wall portion 16c that are connected to the front end face 16a. Corresponding to this fitting portion 18, a fitted portion 15 with a relatively large concave shape is formed by the front end face 15a of the inner reinforcing member 14 and a pair of protrusions 15b that protrude outward in the vehicle width direction Y from the upper and lower ends thereof.

[0067] As Figure 6 shown in (a) to (d), during a side collision of the vehicle, the relatively large convex-shaped fitting portion 18 and the relatively large concave-shaped fitted portion 15 are fitted during a side collision of the vehicle, and the side beam 2 and the outer reinforcing member 13 and the inner reinforcing member 14 inside thereof are crushed. As a result, the fitting portion 18 does not deviate downward, and it is possible to stably receive loads in all directions (the vehicle width direction Y, the front-rear direction X, the up-down direction Z, the torsional direction about the X axis extending in the front-rear direction X, etc.) by the outer reinforcing member 13 and the inner reinforcing member 14. Accordingly, it is possible to suppress the bending deformation of the side beam 2 toward the inside in the vehicle width direction Y during a side collision of the vehicle. Thus, in a structure in which a battery is mounted on the inside in the vehicle width direction Y of the side beam 2, such as a battery electric vehicle, the battery can be reliably protected.

[0068] On the other hand, as a comparative example, as Figure 7 shown in (a) to (d), in a structure in which the outer reinforcing member 13 and the inner reinforcing member 14 do not have a fitting portion and a fitted portion, the first portion 16 of the outer reinforcing member 13 deviates downward, and thus it is not possible to stably receive loads by the outer reinforcing member 13 and the inner reinforcing member 14.

[0069] As other examples of the concave-convex shapes of the fitting portion and the fitted portion, in a combination of a fitting portion 28 having a relatively small convex portion 28a and a fitted portion 25 having a relatively small concave portion 25a as in Figure 4 , it is also possible to prevent the deviation of the outer reinforcing member 13 and the inner reinforcing member 14 by the concave-convex fitting. Or as Figure 5 shown, in a combination of a fitting portion 38 having a relatively small concave portion 38a and a fitted portion 35, the fitted portion 35 has a relatively small convex portion 35a that can be fitted into the concave portion 38a and a lower convex portion 35b that receives the lower corner portion of the fitting portion 38, and it is also possible to prevent the deviation of the outer reinforcing member 13 and the inner reinforcing member 14 by the concave-convex fitting. In addition, even in a combination of relatively small concave-convex shapes - the fitting portions 28, 38 and the fitted portions 25, 35 as in Figures 4 - 5 , as Figure 3 shown, the outer reinforcing member 13 has bracket portions 17a, 17b, and thus more stable fitting can also be achieved.

[0070] The above Figures 3 - 5The engaging portions 18, 28, 38 having a concavo-convex cross-sectional shape and extending in the front-rear direction X and the engaged portions 15, 25, 35 can be easily and continuously formed by roll forming of a metal sheet.

[0071] Next, the second portion 17 having the support portions 17a, 17b will be described in detail.

[0072] (Description of the second portion 17 having the support portions 17a, 17b) As Figure 3 shown, the second portion 17 is continuously formed by roll forming a metal sheet, and the overall shape is a bent < shape or an obtuse V shape. Specifically, the second portion 17 includes: upper and lower paired support portions 17a, 17b, and three fixing plate portions 17c, 17d, 17e (upper fixing plate portion 17c, middle fixing plate portion 17d, lower fixing plate portion 17e) separated from each other in the up-down direction Z.

[0073] The structures of the support portions 17a, 17b are to connect at least one of between the outer longitudinal wall portion 11a and the outer top plate portion 11b and between the outer longitudinal wall portion 11a and the outer bottom plate portion 11c across the ridge lines 11f, 11g (preferably linearly connected by welding). One of the support portions 17a, 17b may be omitted.

[0074] In the present embodiment, the support portions 17a, 17b connect between the outer longitudinal wall portion 11a and the outer top plate portion 11b and between the outer longitudinal wall portion 11a and the outer bottom plate portion 11c across the ridge lines 11f, 11g. Through these support portions 17a, 17b, the angular displacement at the ridge lines 11f, 11g of the outer side beam 11 during a lateral collision of the vehicle can be suppressed.

[0075] The angular displacement is in Figure 3 the closed cross-section C, the displacement of the angle opening or closing at the positions of the ridge lines 11f, 11g, and in some cases, it may also be the displacement that causes the outer side beam 11 to twist about the X-axis extending in the front-rear direction X.

[0076] Specifically, in order to connect the outer top plate portion 11b and the outer longitudinal wall portion 11a of the outer side beam 11, the upper support portion 17a extends obliquely inward in the vehicle width direction Y2 gradually upward across the upper ridge line 11f. The upper end of the upper support portion 17a is connected to the upper fixing plate portion 17c. The upper fixing plate portion 17c is joined to the outer top plate portion 11b by welding or the like. The lower end of the upper support portion 17a is connected to the middle fixing plate portion 17d. The middle fixing plate portion 17d is joined to the reinforcing rib 11h extending in the front-rear direction X of the outer longitudinal wall portion 11a by welding or the like.

[0077] In order to connect the outer bottom plate portion 11c and the outer longitudinal wall portion 11a of the outer side beam 11, the lower bracket portion 17b extends obliquely downward and inward in the vehicle width direction Y2 so as to straddle the lower side ridge line 11g. The lower end of the lower bracket portion 17b is connected to the lower fixing plate portion 17e. The lower fixing plate portion 17e is joined to the outer bottom plate portion 11c by welding or the like. The upper end of the lower bracket portion 17b is connected to the intermediate fixing plate portion 17d, and the intermediate fixing plate portion 17d is joined to the reinforcing rib 11h.

[0078] Therefore, Figure 3 The shown bracket portions 17a and 17b are fixed to the reinforcing rib 11h of the outer longitudinal wall portion 11a of the outer side beam 11 via the intermediate fixing plate portion 17d.

[0079] (Verification of the effects of the bracket portions 17a and 17b) Next, verify the effect of the above-mentioned bracket portions 17a and 17b in improving the torsional rigidity.

[0080] In order to verify the effects of the bracket portions 17a and 17b, consider Figure 8 The test model of the structure having the upper and lower paired bracket portions 17a and 17b as shown. This Figure 8 model is the same as Figure 7 the comparative example, and is a structure in which the outer reinforcing member 13 and the inner reinforcing member 14 do not have a fitting portion and a fitted portion, and the second portion 17 of the outer reinforcing member 13 has the upper and lower paired bracket portions 17a and 17b. Other structures are the same as Figure 3 the same. Figure 8 The shown number 2SW indicates that two-layer spot welding is performed at this place.

[0081] On the other hand, as a comparative example with respect to Figure 8 the test model, consider Figure 9 the existing structure shown. Figure 9 The shown existing structure does not have a bracket portion and corresponds to the structure described in Patent Document 1. Figure 9 In the structure shown, an outer reinforcing member 53, an inner reinforcing member 54, and a partition member 55 are arranged inside the side beam 50. The outer side beam 51 and the inner side beam 52 of the side beam 50 are joined by three-layer spot welding at the position 3SW together with the partition member 55 at the upper and lower flange portions. Two-layer spot welding is performed at the position 2SW at other positions. That is, the outer reinforcing member 53 is welded to the longitudinal wall portion 51a of the outer side beam 51, and the inner reinforcing member 54 is not welded to the inner side beam 52 but is welded to the partition member 55.

[0082] In Figure 8 the structure having the bracket portions 17a and 17b as shown, even when receiving the load input during a vehicle collision, the angular displacement at the ridge lines 11f and 11g of the outer side beam 11 can be suppressed by the bracket portions 17a and 17b. Therefore, whenFigure 8 In the evaluation test of applying torque about the X-axis extending in the front-rear direction X to the test model shown, a torsional rigidity of about 110,000 N / rad was measured, and the mass efficiency was about 40,000 N / rad·kg.

[0083] On the other hand, in Figure 9 the existing structure shown, since there is no bracket portion, angular displacement of the ridge line of the side beam 50 cannot be suppressed. Therefore, in the evaluation test of applying torque about the X-axis to the existing structure shown, it was found that only a torsional rigidity of about 92,000 N / rad could be obtained, and the mass efficiency was about 30,800 N / rad·kg, which was only about 77% of the mass efficiency compared with the structure having bracket portions 17a and 17b shown in Figure 9 From the above test results, it can be seen that the bracket portions 17a and 17b greatly contribute to improving the torsional rigidity. Figure 8 shown.

[0084] (Features of the present embodiment) (1) In the lower body structure of the vehicle of the present embodiment, an outer reinforcing member 13 and an inner reinforcing member 14 are provided inside the side beam 2. Moreover, the outer reinforcing member 13 includes: a fitting portion 18 that fits with the fitting portion 15 of the inner reinforcing member when a lateral collision of the vehicle occurs, that is, when an impact load from the side of the vehicle is input to the side beam 2, and includes bracket portions 17a and 17b. The bracket portions 17a and 17b connect across the ridge lines 11f and 11g of the side beam 2 between the outer longitudinal wall portion 11a and the outer top plate portion 11b of the outer side beam 11 constituting the outer portion in the vehicle width direction of the side beam 2 and at least one of connecting between the outer longitudinal wall portion 11a and the outer bottom plate portion 11c (in the present embodiment, the above two are connected).

[0085] One of the bracket portions 17a and 17b may be omitted.

[0086] In this structure, the angular displacement of the ridge lines 11f and 11g (for example, displacement such as the opening or closing of the corner portion of the closed cross-section C) can be suppressed by the bracket portions 17a and 17b. Therefore, during a lateral collision of the vehicle, the fitting portion 18 of the outer reinforcing member 13 is difficult to deviate in the up-down direction Z, and the fitting portion 18 of the outer reinforcing member 13 and the fitting portion 15 of the inner reinforcing member 14 can be more stably fitted. That is, a more stable crushing action of the outer reinforcing member 13 and the inner reinforcing member 14 can be achieved. Therefore, the outer reinforcing member 13 and the inner reinforcing member 14 can be sufficiently compressed and deformed, and thus the energy absorption amount can be increased.

[0087] Therefore, if the structure of the present embodiment is applied to an electric vehicle in which the battery pack extends under the vehicle floor, the energy absorption of the side beam 2 can be increased and the battery pack can be protected.

[0088] In addition, during normal driving, the angular displacement of the ridge lines 11f and 11g can be suppressed by the support portions 17a and 17b, so that the body rigidity (especially torsional rigidity) can also be improved. Thereby, the torsional deformation of the side beam 2 can be suppressed.

[0089] Moreover, even if the outer reinforcing member 13 and the inner reinforcing member 14 are set to be in contact with each other within the closed cross-section C of the side beam 2, during normal driving, there will be no small angular displacement of the side beam 2, nor will there be an accompanying up-and-down movement of the outer reinforcing member 13, so no abnormal noise will be generated. (2) In the lower body structure of the vehicle according to the present embodiment, one of the fitting portion 18 and the fitted portion 15 has a convex cross-section and extends in the front-rear direction X, and the other has a concave cross-section corresponding to the convex cross-section and extends in the front-rear direction X.

[0091] In the related structure, the fitting portion 18 and the fitted portion 15 can be stably fitted by the fitting of a concave portion (i.e., a groove) and a convex portion (i.e., a rib) that extend in the front-rear direction X respectively. In addition, by roll-forming a metal sheet, one of the fitting portion 18 and the fitted portion 15 can be continuously formed into a shape having a convex cross-section and extending in the front-rear direction X, and the other can be continuously formed into a shape having a concave cross-section and extending in the front-rear direction X, so that a shape capable of achieving stable fitting can be easily formed. (3) In the lower body structure of the vehicle according to the present embodiment, the outer reinforcing member 13 has: a first portion 16 having a fitting portion 18, and a second portion 17 connected to the first portion 16 and having support portions 17a and 17b.

[0093] According to the related structure, the first portion 16 having the fitting portion 18 and the second portion 17 having the support portions 17a and 17b can be separately and continuously formed into desired cross-sectional shapes by roll-forming a metal sheet. Then, the formed first portion 16 and the second portion 17 are connected, whereby the outer reinforcing member 13 having the fitting portion 18 and the support portions 17a and 17b can be easily manufactured. (4) In the lower body structure of the vehicle according to the present embodiment, the first portion 16 is fixed to the side beam 2 via the second portion 17.

[0095] According to the related structure, in the outer reinforcing member 13, the collision load input to the side beam 2 during a side collision of the vehicle can be effectively transmitted from the second portion 17 to the first portion 16. Thereby, the load can be smoothly transmitted from the support portions 17a and 17b of the second portion 17 to the fitting portion 18 of the first portion 16. (5) In the lower body structure of the vehicle according to the present embodiment, the first portion 16 has an upper wall portion 16b that connects the front end face 16a, which is the main portion of the fitting portion 18, to the bracket portions 17a and 17b of the second portion 17, and a lower wall portion 16c located below the upper wall portion 16b. The upper wall portion 16b and the lower wall portion 16c have stepped portions 16f and 16g (i.e., reinforcing ribs or concavo-convex portions extending in the front-rear direction X) that serve as deformation promoting portions that partially promote deformation during a side collision of the vehicle.

[0097] In the related structure, during a side collision of the vehicle, in the first portion 16 of the outer reinforcing member 13, the fitting portion 18 is fitted with the fitted portion 15 of the inner reinforcing member 14 during a side collision of the vehicle, and the stepped portions 16f and 16g, which are the deformation promoting portions of the upper wall portion 16b and the lower wall portion 16c, partially promote deformation, thereby further increasing the amount of energy absorption in the outer reinforcing member 13. (6) In the lower body structure of the vehicle according to the present embodiment, the first portion 16 is made of a plate material. The deformation promoting portion is composed of a plurality of stepped portions 16f and 16g formed by partially bending and deforming (zigzagging or bending) the plate material. In the related structure, since the deformation promoting portion is composed of a plurality of stepped portions 16f and 16g, the deformation promoting portion can be formed in the upper wall portion 16b and the lower wall portion 16c of the first portion 16 of the outer reinforcing member 13 with a simple structure (in other words, by a simple shape change). During a side collision of the vehicle, folding deformation (so-called bellows-like deformation) occurs at the plurality of stepped portions 16f and 16g, thereby enabling the first portion 16 of the outer reinforcing member 13 to deform easily. At the same time, the amount of energy absorption in the outer reinforcing member 13 can be easily set or controlled by the stepped shape of the first portion 16. (7) In the lower body structure of the vehicle according to the present embodiment, the bracket portions 17a and 17b connect between the outer longitudinal wall portion 11a and the outer roof portion 11b of the side beam 2 and between the outer longitudinal wall portion 11a and the outer floor portion 11c across the ridge lines 11f and 11g.

[0101] In the related structure, the bracket portions 17a and 17b connect them by straddling two ridge lines 11f and 11g formed between the outer roof portion 11b, the outer longitudinal wall portion 11a, and the outer floor portion 11c of the side beam 2, so that the amount of energy absorption of the side beam 2 during a side collision of the vehicle can be further increased, and the rigidity of the side beam 2 during normal driving can be further increased. (8) In the lower body structure of the vehicle according to the present embodiment, the outer longitudinal wall portion 11a has a reinforcing rib 11h extending in the front-rear direction X ( Figure 3In the middle is a recess that is recessed inward in the vehicle width direction Y). The bracket portions 17a and 17b are fixed to the reinforcing rib 11h.

[0103] According to the relevant structure, the outer longitudinal wall portion 11a of the side beam 2 has a reinforcing rib 11h extending in the front-rear direction X, thereby improving the rigidity of the outer longitudinal wall portion 11a (especially the bending stiffness in the vehicle width direction Y). Moreover, the bracket portions 17a and 17b are fixed to the highly rigid reinforcing rib 11h in the outer longitudinal wall portion 11a. Thus, the impact load during a vehicle side collision can be smoothly transmitted from the outer longitudinal wall portion 11a of the outer side beam 11 to the bracket portions 17a and 17b of the outer side reinforcing member 13, and the energy absorption amount in the outer side reinforcing member 13 can be further increased.

[0104] (9) In the lower body structure of the vehicle of the present embodiment, the inner side reinforcing member 14 and the outer side reinforcing member 13 are formed by roll-forming a metal sheet.

[0105] According to the relevant structure, since the inner side reinforcing member 14 and the outer side reinforcing member 13 are formed by roll-forming a metal sheet, they can be easily and inexpensively continuously formed into a desired cross-sectional shape. And since the inner side reinforcing member 14 and the outer side reinforcing member 13 are continuously formed by roll-forming, they can be applied to vehicles of various vehicle total lengths, that is, they can adapt to vehicle size changes.

[0106] Moreover, the inner side reinforcing member 14 and the outer side reinforcing member 13 that are continuously formed by roll-forming reinforce the side beam 2 in a relatively long section in the front-rear direction X. Therefore, a high energy absorption amount can be obtained regardless of which section in the front-rear direction X of the side beam 2 collides with an obstacle. Thus, the battery can be effectively protected in a battery electric vehicle. (10) In the lower body structure of the vehicle of the present embodiment, like Figure 3 the front side intermediate cross member 7, four cross members 6-9 (the first cross member 6, the front side intermediate cross member 7, the second cross member 8, the third cross member 9) extending in the vehicle width direction Y are connected to the inner longitudinal wall portion 12a of the inner side beam 12 in the up-down direction Z within a range including the overlapping portion of the inner side reinforcing member 14 and the side beam 2.

[0108] According to the relevant structure, during a vehicle side collision, the cross members 6-9 can support the overlapping portion of the inner side reinforcing member 14 and the side beam 2 from the inner side of the vehicle and effectively receive the collision load. Thereby, the energy absorption amount in the side beam 2 and the inner side reinforcing member 14 can be further increased. Therefore, in an electric vehicle where the battery pack extends under the vehicle floor, the battery pack can be effectively protected.

[0109] (Modification example) In the above-described embodiment, as an example of the deformation promoting portions in the upper wall portion 16b and the lower wall portion 16c of the first portion 16 of the outer reinforcing member 13, the stepped portions 16f, 16g obtained by bending deformation of the plate material are illustrated, that is, the reinforcing ribs or the concavo-convex portions extending in the front-rear direction X. However, the present invention is not limited thereto, and any structure that can promote the deformation of the upper wall portion 16b and the lower wall portion 16c is acceptable. The present invention includes deformation promoting portions of various shapes and structures. For example, as the deformation promoting portion, a cut may be formed in the upper wall portion 16b and the lower wall portion 16c, or a thin portion may be partially formed.

[0110]

Practicality

[0111]

Number Explanation

Claims

1. A lower body structure of a vehicle, characterized in that: have: a side member having a closed cross section and extending in the front-rear direction of the vehicle; an outer reinforcement member disposed inside the side beam and extending along the front-rear direction; The inner reinforcing member is arranged inside the side beam at a position closer to the vehicle inner side than the outer reinforcing member and extends along the front-rear direction; wherein, The side beam has: Outer longitudinal wall, an inner longitudinal wall portion, which is located on the vehicle inner side relative to the outer longitudinal wall portion, an outer top plate portion connected to the upper end of the outer vertical wall portion, an outer bottom plate portion connected to the lower end of the outer vertical wall portion, The outer longitudinal wall portion, the inner longitudinal wall portion, the outer top plate portion, and the outer bottom plate portion form at least a portion of the closed cross section of the side beam. A ridge line extending in the front-rear direction is formed between the outer vertical wall portion and the outer top plate portion and between the outer vertical wall portion and the outer bottom plate portion, respectively. The inner reinforcing member is fixed to the inner vertical wall portion and has an engaged portion that engages with the outer reinforcing member when an impact load from the side of the vehicle is input to the side member. The outer reinforcing member has: a fitting portion which fits with the fitted portion of the inner reinforcing member when an impact load from the side of the vehicle is input to the side beam, The bracket portion at least one of connects the outer vertical wall portion and the outer top plate portion across the ridge line and connects the outer vertical wall portion and the outer bottom plate portion.

2. The vehicle lower body structure according to claim 1, characterized in that : One of the fitting portion and the fitted portion has a convex cross section and extends in the front-rear direction, and the other has a concave cross section corresponding to the convex cross section and extends in the front-rear direction.

3. The lower body structure of a vehicle according to claim 1 or 2, characterized in that : The outer reinforcing member includes a first portion having the fitting portion and a second portion connected to the first portion and having the bracket portion.

4. The vehicle lower body structure according to claim 3, characterized in that : The first portion is fixed to the side member via the second portion.

5. The vehicle lower body structure according to claim 3, characterized in that : The first portion includes an upper wall portion connecting the fitting portion and the second portion, and a lower wall portion located below the upper wall portion and connecting the fitting portion and the second portion. The upper wall portion and the lower wall portion include a deformation promoting portion that partially promotes deformation when the vehicle collides sideways.

6. The vehicle lower body structure according to claim 5, characterized in that : The first part is composed of a plate. The deformation promoting portion is composed of a plurality of step portions formed by partially bending and deforming the plate material.

7. The vehicle lower body structure according to claim 1 or 2, characterized in that : The bracket portion connects between the outer vertical wall portion and the outer top plate portion and between the outer vertical wall portion and the outer bottom plate portion in the side sill across the ridge line.

8. The vehicle lower body structure according to claim 1 or 2, characterized in that : The outer longitudinal wall portion has a reinforcing rib extending along the front-rear direction, The bracket portion is fixed to the reinforcing rib.

9. The vehicle lower body structure according to claim 1 or 2, characterized in that : The inner reinforcing member and the outer reinforcing member are formed by roll forming a metal plate.

10. The vehicle lower body structure according to claim 1 or 2, characterized in that : It also has a crossbeam extending in the vehicle width direction. The cross member is connected to the inner vertical wall portion of the side sill in a range including an overlapping portion between the inner reinforcing member and the side sill in the up-down direction.

Images