Vehicle side sill reinforcement structure

Abstract

To provide a side sill reinforcement structure for vehicles characterized in that an absorption quantity of impact energy is upgraded.SOLUTION: A reinforcement member 40 that reinforces a side sill 20 includes plural closed section parts 51 to 54 that are concatenated in a vehicle width direction. The plural closed section parts 51 to 54 are defined with a pair of webs 41 and 42 that are opposed to each other in a vertical direction, and plural side walls 47a to 47e that are arranged in the vehicle width direction with a space between adjoining ones and connect the pair of webs 41 and 42. Thicknesses tw2 and tw3 of webs 44A and 44B of intermediate closed section parts 59A and 59B are larger than a thickness tw1 of a web 43A of an outermost closed section part 58A, and are larger than a thickness tw4 of a web 43B of an innermost closed section part 58B.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a side sill reinforcement structure for a vehicle.

Background Art

[0002] Conventionally, improvement of the safety of vehicle occupants has been demanded. For this purpose, improvement of the collision safety performance has been achieved by improving the strength of the vehicle body. In particular, a side collision (hereinafter also referred to as a side impact) is likely to apply a strong impact to the passenger compartment, and high impact absorption performance is required for a side impact. That is, when an object such as a pole collides with the side portion of the vehicle body due to the vehicle body spinning or the like, it is necessary to absorb the impact energy and protect the passenger compartment. On the other hand, against the backdrop of the intensification of problems such as global warming, the movement to improve the fuel efficiency of automobiles is accelerating. It is known that weight reduction of the vehicle body is effective for improving the fuel efficiency.

[0003] For example, Patent Document 1 discloses a vehicle body lower structure that achieves both improvement of safety performance against side impacts and weight reduction. In this vehicle body lower structure, a reinforcing member is disposed under a skeletal member disposed on a side portion of the vehicle body called a rocker or a side sill, and the reinforcing member absorbs impact energy during a side impact.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In a side impact of a vehicle, the impact load tends to increase as the amount of deformation (displacement) of the reinforcing member in the vehicle width direction increases. In the above-described reinforcing member, there is room for improvement in the amount of impact energy absorbed.

[0006] The present invention aims to improve the absorption of impact energy and reduce the weight of the vehicle body in a vehicle side sill reinforcement structure. [Means for solving the problem]

[0007] One aspect of the present invention provides a vehicle side sill reinforcement structure comprising a side sill extending in the vehicle length direction on the side of a vehicle, and a reinforcing member that reinforces the side sill, wherein the reinforcing member has a plurality of closed sections connected in the vehicle width direction in a cross section perpendicular to the vehicle length direction, the plurality of closed sections are defined by a pair of webs arranged opposite to each other in the vertical direction, and a plurality of side walls arranged at intervals in the vehicle width direction and connecting the pair of webs, and the plurality of closed sections include an outermost closed section located on the outermost side in the vehicle width direction, an innermost closed section located on the innermost side in the vehicle width direction, and one or more intermediate closed sections located between the outermost closed section and the innermost closed section, wherein the thickness of the web of the intermediate closed section is greater than the thickness of the web of the outermost closed section and greater than the thickness of the web of the innermost closed section.

[0008] With the above configuration, when a side impact occurs and the deformation of the reinforcing member in the vehicle width direction becomes large, the deformation area expands in the vehicle length direction, and the load required to break the reinforcing member also increases. When the outermost closed section is sufficiently deformed, deformation of the intermediate closed section begins. The web of this intermediate closed section is relatively thick. Coupled with the expansion of the deformation area, the load required to break the intermediate closed section becomes even larger. The load increases efficiently with increasing thickness. As a result, the amount of load required to displace the entire reinforcing member, i.e., the amount of impact energy absorbed by the reinforcing member, increases. The webs of the outermost closed section and the innermost closed section are relatively thin. Therefore, the weight increase of the reinforcing member can be suppressed, and furthermore, it is possible to reduce weight while maintaining or improving energy absorption performance compared to a reinforcing member with uniform thickness.

[0009] Multiple intermediate closed sections may be provided, and the thickness of the web of each of the multiple intermediate closed sections may increase sequentially from the outside to the inside in the vehicle width direction.

[0010] With the above configuration, as the thickness increases towards the inside in the vehicle width direction, the deformation area also expands, which in turn allows for an efficient increase in the amount of impact energy absorbed in the inner portion of the reinforcing member in the vehicle width direction.

[0011] Multiple intermediate closed sections may be provided, and the thickness of the web of the multiple intermediate closed sections may gradually decrease from the outside to the inside in the vehicle width direction.

[0012] The above configuration makes it easier to achieve weight reduction. Furthermore, as described above, as the deformation of the reinforcing member in the vehicle width direction increases, the load required for the reinforcing member to break increases based on the expansion of the deformation area in the vehicle length direction. Therefore, even if the thickness is progressively reduced, the amount of energy that can be absorbed by the inner portion of the reinforcing member in the vehicle width direction can be secured.

[0013] The thickness of the web in the innermost closed section may be greater than the thickness of the web in the outermost closed section.

[0014] According to the above configuration, deformation of the inner end of the reinforcing member in the vehicle width direction can be suppressed. Components located further inside the reinforcing member in the vehicle width direction (for example, a battery) can be protected.

[0015] The reinforcing member may be placed inside the side sill.

[0016] According to the above configuration, the internal space of the reinforcing member can be effectively utilized, and the vehicle side sill reinforcement structure can be made smaller.

[0017] The reinforcing member may be positioned adjacent to the side sill.

[0018] According to the above configuration, the side sill can be easily reinforced. Note that "adjacent to the side sill" means being arranged close to the side sill regardless of whether it is in any of the upper, lower, left, or right positions in a cross-section perpendicular to the vehicle length direction of the side sill.

Effects of the Invention

[0019] According to the present invention, in the vehicle side sill reinforcement structure, the amount of absorbed impact energy can be improved, and the vehicle body can be lightweight.

Brief Description of the Drawings

[0020] [Figure 1] Side view of the vehicle. [Figure 2] Cross-sectional view of the vehicle side sill reinforcement structure according to the first embodiment. [Figure 3] Cross-sectional view of the reinforcing member in the first embodiment. [Figure 4] Graph showing the load against displacement. [Figure 5] Graph showing the energy absorption efficiency against displacement. [Figure 6] Cross-sectional view of the reinforcing member according to the first modification. [Figure 7] Cross-sectional view of the reinforcing member according to the second modification. [Figure 8] Cross-sectional view of the reinforcing member according to the third modification. <元素符号 [Figure 9] Cross-sectional view of the vehicle side sill reinforcement structure according to the second embodiment. [Figure 10] Cross-sectional view of the vehicle side sill reinforcement structure according to the third embodiment. [Figure 11] Cross-sectional view of the vehicle side sill reinforcement structure according to the fourth embodiment. [Figure 12] Cross-sectional view of the vehicle side sill reinforcement structure according to the fifth embodiment. [Figure 13] Cross-sectional view of the reinforcing member in the fifth embodiment. [Figure 14] Cross-sectional view of the vehicle side sill reinforcement structure according to the sixth embodiment.

Modes for Carrying Out the Invention

[0021] Embodiments will be described below with reference to the drawings. The same reference numerals are used throughout the drawings for identical or corresponding elements to avoid redundant detailed explanations. In each drawing, the front-rear direction (vehicle length direction) of vehicle 1 is indicated by the X direction, the vehicle width direction by the Y direction, and the up-down direction by the Z direction.

[0022] (First Embodiment) Referring to Figure 1, Vehicle 1 is equipped with a battery unit 10 as a power supply for the motor (not shown) used for driving. The battery unit 10 is located in the center of the vehicle body, under the floor of the passenger compartment R, and is positioned over almost the entire surface.

[0023] Vehicle 1 may be, for example, an electric vehicle or a plug-in hybrid vehicle. The type of vehicle 1 is not particularly limited and may be a passenger car, a truck, a work vehicle, or other mobility device. In the following, the vehicle side sill reinforcement structure according to this embodiment will be described using the case of a passenger car type electric vehicle as shown in Figure 1 as an example.

[0024] Referring to Figure 2, the battery unit 10 includes a battery 11 and a battery case 12 that houses the battery 11. The battery case 12 has an upper case 13 and a lower case 14. The upper case 13 has a housing portion 13a that is concave upwards and a flange portion 13b provided around the housing portion 13a in a plan view. The lower case 14 has a housing portion 14a that is concave downwards and a flange portion 14b provided around the housing portion 14a in a plan view. The upper case 13 and the lower case 14 are joined by the flange portions 13b and 14b being bonded together. The battery 11 is housed in a housing space S1 defined by the housing portion 13a of the upper case 13 and the housing portion 14a of the lower case 14.

[0025] On the outer side of the battery unit 10 in the vehicle width direction (left side in Figure 2), a side sill 20 is positioned on the side of the vehicle 1, extending in the vehicle length direction. The side sill 20 is a structural member that constitutes the outer surface of the lower part of the vehicle 1.

[0026] The side sill 20 is hollow. In this embodiment, the side sill 20 is composed of a side sill outer 21 positioned on the outside in the vehicle width direction and a side sill inner 22 positioned on the inside in the vehicle width direction. Both the side sill outer 21 and the side sill inner 22 are formed by bending sheet metal into a hat shape, and they are bonded together to form an internal space S2. The side sill 20 may be made of steel.

[0027] A floor panel 30 is positioned above the battery unit 10. The floor panel 30 is a plate material that forms the underside of the passenger compartment R. Above the floor panel 30, a cross member 31 is positioned extending in the vehicle width direction. Although not shown in detail, multiple cross members 31 are provided at intervals in the vehicle length direction.

[0028] Below the side sill 20, a reinforcing member 40 is positioned to reinforce the side sill 20. The reinforcing member 40 is positioned adjacent to the side sill 20. The reinforcing member 40 extends along the side sill 20 in the vehicle-length direction and connects the side sill 20 to the battery unit 10. The reinforcing member 40 is made of, for example, an extruded aluminum alloy.

[0029] Referring to Figure 3, the reinforcing member 40 has a pair of webs 41 and 42 that are arranged opposite each other in the vertical direction, and a plurality of side walls 47a to 47e that are spaced apart in the vehicle width direction and connect the pairs of webs 41 and 42 to each other.

[0030] The side walls 47a to 47e include an outermost wall 48A that connects the outer ends of a pair of webs 41 and 42 in the vehicle width direction in the vertical direction, and an innermost wall 48B that connects the inner ends of a pair of webs 41 and 42 in the vehicle width direction in the vertical direction. The dimensions of the webs 41 and 42 in the vehicle width direction are longer than the distance between the webs 41 and 42 (the height of the side walls 47a to 47e). The pair of webs 41 and 42, the outermost wall 48A, and the innermost wall 48B form a rectangular closed cross section that is elongated in the vehicle width direction.

[0031] The side walls 47a to 47e include one or more intermediate side walls 49A, 49B, 49C that connect the inner surfaces of a pair of webs 41, 42 vertically between the outermost wall 48A and the innermost wall 48B in the vehicle width direction. As a result, the above-mentioned horizontally elongated rectangular closed section is subdivided in the vehicle width direction by one or more intermediate side walls 49A, 49B, 49C. In other words, the reinforcing member 40 has a plurality of closed section portions 51 to 54 that are connected in the vehicle width direction in a section perpendicular to the vehicle length direction.

[0032] Each closed section 51-54 is defined by two adjacent side walls in the vehicle width direction and a portion of a pair of webs 41, 42 connecting the two side walls. Each closed section 51-54 is square or rectangular in shape and has a hollow enclosed by walls forming its four sides. The hollows of two adjacent closed sections are separated by one intermediate side wall. That is, two adjacent closed sections share one intermediate side wall.

[0033] The multiple closed sections 51 to 54 can be classified into an outermost closed section 58A located on the outermost side in the vehicle width direction, an innermost closed section 58B located on the innermost side in the vehicle width direction, and one or more intermediate closed sections 59 (59A, 59B) located between the outermost closed section 58A and the innermost closed section 58B in the vehicle width direction.

[0034] In this embodiment, as merely an example, there are three intermediate side walls 49A, 49B, and 49C. In the following, each of the five side walls 47a to 47e may be described by assigning ordinal numbers sequentially from the outside to the inside in the vehicle width direction. The first side wall 47a corresponds to the outermost wall 48A, the fifth side wall 47e corresponds to the innermost wall 48B, and the second to fourth side walls 47b, 47c, and 47d correspond to the intermediate side walls 49A, 49B, and 49C. In the following, each of the multiple intermediate side walls 49A, 49B, and 49C may be described by assigning ordinal numbers sequentially from the outside to the inside in the vehicle width direction. The second side wall 47b corresponds to the first intermediate side wall 49A, the third side wall 47c corresponds to the second intermediate side wall 49B, and the fourth side wall 47d corresponds to the third intermediate side wall 49C.

[0035] The number of closed sections 51-54 is one more than the number of intermediate side walls 49A, 49B, and 49C (and one less than the total number of side walls 47a-47e, including the outermost wall 48A and the innermost wall 48B). In this embodiment, as merely an example, there are four closed sections 51-54. In the following, each of the four closed sections 51-54 may be described by assigning an ordinal number sequentially from the outside to the inside in the vehicle width direction. The first closed section 51 corresponds to the outermost closed section 58A, the fourth closed section 54 corresponds to the innermost closed section 58B, and the second and third closed sections 52 and 53 correspond to the intermediate closed sections 59. In the following, each of the multiple intermediate closed sections 59 may be described by assigning an ordinal number sequentially from the outside to the inside in the vehicle width direction. The second closed section 52 corresponds to the first intermediate closed section 59A, and the third closed section 53 corresponds to the second intermediate closed section 59B.

[0036] The upper web 41 includes a first upper web 41a defining the first closed section 51 (outermost closed section 58A), a second upper web 41b defining the second closed section 52 (first intermediate closed section 59A), a third upper web 41c defining the third closed section 53 (second intermediate closed section 59B), and a fourth upper web 41d defining the fourth closed section 54 (innermost closed section 58B). The first to fourth upper webs 41a to 41d are sequentially connected in the vehicle width direction to constitute the upper web 41.

[0037] The lower web 42 includes a first lower web 42a defining the first closed section 51 (outermost closed section 58A), a second lower web 42b defining the second closed section 52 (first intermediate closed section 59A), a third lower web 42c defining the third closed section 53 (second intermediate closed section 59B), and a fourth lower web 42d defining the fourth closed section 54 (innermost closed section 58B). The first to fourth lower webs 42a to 42d are sequentially connected in the vehicle width direction to constitute the lower web 42.

[0038] The first side wall 47a (outermost wall 48A) defines the first closed section 51 (outermost closed section 58A). The second side wall 47b (first intermediate side wall 49A) defines the first closed section 51 (outermost closed section 58A) and also defines the second closed section 52 (first intermediate closed section 59A) adjacent to it in the vehicle width direction. The third side wall 47c (second intermediate side wall 49B) defines the second closed section 52 (first intermediate closed section 59A) and also defines the third closed section 53 (second intermediate closed section 59B) adjacent to it in the vehicle width direction. The fourth side wall 47d (third intermediate side wall 49C) defines the third closed section 53 (second intermediate closed section 59B) and also defines the fourth closed section 54 (innermost closed section 58B) adjacent to it in the vehicle width direction. The fifth side wall 47e (innermost wall 48B) defines the fourth closed section 54 (innermost closed section 58B).

[0039] In this embodiment, in each closed section 51 to 54, the thickness of the upper web and the thickness of the lower web (vertical dimension) are equal to each other. Therefore, in the following description, when simply referred to as "web thickness," it refers to both the thickness of the upper web and the thickness of the lower web. In each closed section 51 to 54, the web thickness is uniform in the vehicle width direction. The thickness of each side wall 47a to 47e (vehicle width dimension) is uniform in the vertical direction. The reinforcing member 40 is symmetrical with respect to the axis of symmetry C extending in the vehicle width direction, with respect to the center in the vertical direction in a section perpendicular to the vehicle length direction.

[0040] Hereinafter, the first upper web 41a and the first lower web 42a may be collectively referred to as the "web 43A" of the outermost closed section 58A. The fourth upper web 41d and the fourth lower web 42d may be collectively referred to as the "web 43B" of the innermost closed section 58B. The second upper web 41b and the second lower web 42b may be collectively referred to as the "web 44A" of the first intermediate closed section 59A. The third upper web 41c and the third lower web 42c may be collectively referred to as the "web 44B" of the second intermediate closed section 59B.

[0041] Returning to FIG. 2, the fourth blocking surface portion 54 (the innermost blocking surface portion 58B) is joined by the battery unit 10 and the bolt 60. The bolt 60 extends in the vertical direction and penetrates the fourth upper web 41d, the fourth lower web 42d, the flange portion 13b of the upper case 13, the flange portion 14b of the lower case 14, and the floor panel 30, joining them. From the perspective of battery replacement efficiency, the bolt 60 is preferably inserted and fastened from bottom to top. Also, in order to ensure high joining strength, it is preferable to use a cylindrical collar 61 that covers the periphery of the bolt 60 to suppress deformation of the fastening portion of the bolt 60.

[0042] The first blocking surface portion 51 (the outermost blocking surface portion 58A) is joined by the side sill 20 and the bolt 70. The bolt 70 extends in the vertical direction, penetrates the first upper web 41a and the first lower web 42a, and the side sill outer 21, terminates within the internal space S2, and joins them. Similarly to the above, the bolt 70 is preferably inserted and fastened from bottom to top, and it is preferable to use a cylindrical collar 71 that covers the periphery of the bolt 70.

[0043] Returning to FIG. 3, the thicknesses tw2, tw3 of the webs of the intermediate blocking surface portion are thicker than the thickness tw1 of the web of the outermost blocking surface portion and thicker than the thickness tw4 of the web of the innermost blocking surface portion.

[0044] In this embodiment, the thicknesses tw2, tw3 of the webs of the plurality of intermediate blocking surface portions are equal to each other. Also, the thickness tw1 of the web of the outermost blocking surface portion and the thickness tw4 of the web of the innermost blocking surface portion are equal to each other. That is, the web thicknesses tw1 to tw4 satisfy the following formula: tw1 = tw4 < tw2 = tw3.

[0045] The thicknesses tw2 and tw3 of the webs 44A and 44B of the intermediate blocking surfaces 59A and 59B are 1.1 times or more, preferably 1.3 times or more, and 2.5 times or less, preferably 1.8 times or less, and most preferably 1.5 times the thickness tw1 of the web 43A of the outermost blocking surface 58A. The thicknesses tw2 and tw3 of the webs 44A and 44B of the intermediate blocking surfaces 59A and 59B are 1.1 times or more, preferably 1.3 times or more, and 2.0 times or less, preferably 1.8 times or less, and most preferably 1.5 times the thickness tw4 of the web 43B of the innermost blocking surface 58B.

[0046] The thickness tw1 of the web 43A of the outermost blocking surface 58A is 2 to 5 mm, and the thickness tw4 of the web 43B of the innermost blocking surface 58B is also the same. The thicknesses tw2 and tw3 of the webs 44A and 44B of the intermediate blocking surfaces 59A and 59B are 2.2 to 6 mm.

[0047] Also, the thicknesses ts2 to ts4 of the intermediate side walls 49A, 49B, and 49C are thicker than the thickness ts1 of the outermost side wall 48A and thicker than the thickness ts5 of the innermost side wall 48B.

[0048] In this embodiment, the thicknesses ts2 to ts4 of the intermediate side walls 49A, 49B, and 49C are equal to each other. Also, the thickness ts1 of the outermost side wall 48A and the thickness ts5 of the innermost side wall 48B are equal to each other. That is, the thicknesses ts1 to ts5 of the side walls 47a to 47e satisfy the following formula: ts1 = ts5 < ts2 = ts3 = ts4. Note that the thicknesses ts2 to ts4 of the intermediate side walls 49A, 49B, and 49C may be approximately equal to the thicknesses tw2 and tw3 of the webs 44A and 44B of the intermediate blocking surfaces 59A and 59B. The thicknesses ts1 and ts5 of the outermost side wall 48A and the innermost side wall 48B may be approximately equal to the thicknesses tw1 and tw4 of the webs 43A and 43B of the outermost blocking surface 58A and the innermost blocking surface 58B.

[0049] Figures 4 and 5 are graphs evaluating the performance of the reinforcing member 40 according to this embodiment. In Figures 4 and 5, the solid line represents this embodiment, and the dashed line represents the comparative example. In the comparative example, the thickness of the web and side walls is uniform. The cross-sectional area of ​​the reinforcing member perpendicular to the vehicle length direction is the same between this embodiment and the comparative example, and the material is also the same. That is, the weight is the same between this embodiment and the comparative example.

[0050] Referring to Figure 4, the amount of energy absorbed is expressed as the integral value (J) of the graph shown by displacement S (mm) and load P (kN). Displacement S represents the amount of deformation of the reinforcing member 40 in the vehicle width direction. Load P represents the impact load received by the reinforcing member 40 during a side collision. In both this embodiment and the comparative example, four peaks are observed. At each peak, one closed cross-section is fractured or crushed.

[0051] In the comparative example, as the displacement increases (i.e., as the multiple closed sections are sequentially crushed from the outside to the inside in the vehicle width direction), the peak load value increases slowly and linearly. This is because the deformation region due to a side impact expands in the vehicle length direction as it moves inward in the vehicle width direction. Even if the wall thickness is uniform and the strength is the same across multiple closed sections in a section perpendicular to the vehicle length direction, the load required to crush a closed section increases as it moves inward in the vehicle width direction.

[0052] In contrast, in this embodiment, the web 43A and outermost wall 48A (first side wall 47a) of the outermost closed section 58A are thin. Furthermore, the thickness tw1 of the web 43A of the outermost closed section 58A is thinner than that of the comparative example. Therefore, the peak value of the initial load, i.e., the load that crushes the outermost closed section 58A, is lower than that of the comparative example.

[0053] However, in this embodiment, the thicknesses tw2 and tw3 of the webs 44A and 44B of the intermediate closed sections 59A and 59B are greater than the thickness tw1 of the web 43A of the outermost closed section 58A. Furthermore, the thicknesses of the webs 44A and 44B of the intermediate closed sections 59A and 59B are greater than the wall thickness of the comparative example. Consequently, the second peak value, i.e., the load required to crush the first intermediate closed section 59A, is higher than that of the comparative example. The same applies to the third peak value; the difference between the peak value and that of the comparative example is greater for the third peak than for the second peak.

[0054] As described above, as the displacement increases, the deformation region expands, so the load required to crush the closed sections 51-54 increases towards the inside in the vehicle width direction. Here, if the wall thickness of the closed sections 51-54 increases, the load required to crush the closed sections 51-54 over a wide deformation region increases dramatically compared to the case where the wall thickness is uniform. This embodiment focuses on this point.

[0055] Even if the outermost closed section 58A is made thinner, as long as the thickness is maintained in the intermediate closed sections 59A and 59B, the second and subsequent peak values ​​can be efficiently increased. Therefore, compared to the case where the wall thickness is uniform, the integral value can be increased even if the weight (cross-sectional area perpendicular to the vehicle length direction when the material is the same) is reduced. In other words, the energy absorption performance of the side sill structure can be improved while reducing the weight of the reinforcing member 40.

[0056] Figure 5 illustrates this. In this embodiment, in the initial stages of deformation (when the displacement S is small), the web 43A of the outermost closed section 58A is thin, making it difficult to generate sufficient load, resulting in a lower energy absorption per unit weight compared to the comparative example. However, as the displacement increases and the deformation extends to the intermediate closed sections 59A and 59B, the effect of increased load due to the increased thickness becomes apparent. Despite the increased thickness, the energy absorption per unit weight significantly exceeds that of the comparative example.

[0057] Since the web 43B of the innermost closing portion 58B is thinner than the webs 44A and 44B of the intermediate closing portions 59A and 59B, in this embodiment, the last peak value (the fourth peak value) is smaller than the nearest peak value (the third peak value). However, even if the web 43B is thin, the load required for crushing the innermost closing portion 58B increases due to the spread of the deformation region, so the last peak value (the fourth peak value) is higher than the first peak value. That is, even with thinning, the load can be increased, and the compatibility between weight reduction and improvement of energy absorption performance can be further achieved. Also, by thinning the innermost closing portion 58B, it is possible to prevent the load from becoming excessively high. For this reason, it is possible to suppress the input of a high load to the configuration further inward in the vehicle width direction of the innermost closing portion 58B, that is, the battery unit 10, and protect the battery unit 10.

[0058] (Modification of the First Embodiment) FIG. 6 shows a cross section of the reinforcing member 40 according to the first modification. In the first modification, the thicknesses of the webs 44A and 44B of the plurality of intermediate closing portions 59A and 59B gradually increase from the outside to the inside in the vehicle width direction. In this example, the number of intermediate closing portions 59A and 59B is two. The thickness tw3 of the web 44B of the second intermediate closing portion 59B is thicker than the thickness tw2 of the web 44A of the first intermediate closing portion 59A. That is, the thicknesses tw1 to tw4 of the webs satisfy the following formula: tw1 = tw4 < tw2 < tw3.

[0059] Since the thickness increases toward the inside in the vehicle width direction, taking into account that the load required for deformation also increases, the energy absorption amount can be effectively increased on the inside in the vehicle width direction.

[0060] FIG. 7 shows a cross-section of the reinforcing member 40 according to the second modification. In the second modification, the thickness of the webs of the plurality of intermediate blocking portions gradually decreases from the outer side to the inner side in the vehicle width direction. In this example, the number of intermediate blocking portions is two. The thickness tw3 of the web of the second intermediate blocking portion (the third blocking portion) is thinner than the thickness tw2 of the web of the first intermediate blocking portion (the first blocking portion). That is, the web thicknesses tw1 to tw4 satisfy the following formula: tw1 = tw4 < tw3 < tw2.

[0061] As the displacement of the reinforcing member 40 increases, the load required for deformation increases. Therefore, even if the wall thickness is gradually reduced, the amount of energy that can be absorbed on the inner side in the vehicle width direction can be ensured. Therefore, according to this example, in addition to achieving weight reduction of the reinforcing member 40, it is effective when it is desired to absorb energy at a stage where relatively little deformation occurs.

[0062] FIG. 8 shows a cross-section of the reinforcing member 40 according to the third modification. In the third modification, the thicknesses of the webs 44A and 44B of the plurality of intermediate blocking portions 59A and 59B are equal to each other, similar to the first embodiment. The thickness of the web 43B of the innermost blocking portion 58B is thinner than the thicknesses of the webs 44A and 44B of the intermediate blocking portions 59A and 59, while being thicker than the thickness of the web of the outermost blocking portion 58A. That is, the web thicknesses tw1 to tw4 satisfy the following formula: tw1 < tw4 < tw2 = tw3.

[0063] The amount of energy that can be absorbed at the inner end portion of the reinforcing member 40 in the vehicle width direction increases, and this inner end portion becomes difficult to deform. Therefore, components arranged on the inner side in the vehicle width direction of the reinforcing member 40, such as the battery unit 10 (see FIG. 2), can be protected. Deformation can be suppressed.

[0064] (Second Embodiment) Referring to Figure 9, in the side sill reinforcement structure according to the second embodiment, the reinforcing member 40 is in an inverted L shape when viewed from the vehicle length direction and has a protruding closed section portion 58C positioned below and adjacent to the innermost closed section portion 58B. The protruding closed section portion 58C is rectangular in cross-section perpendicular to the vehicle length direction. The protruding closed section portion 58C is located below the lower case 14 of the battery case 12. On the other hand, a cross member 32 extending in the vehicle width direction is provided along the lower surface of the lower case 14. The protruding closed section portion 58C is provided with a support wall 40a extending inward in the vehicle width direction from its lower wall. The support wall 40a supports the cross member 32 from below.

[0065] With this configuration, when a side impact occurs, the load is transmitted from the protruding closed section 58C to the cross member 32. As a result, the reinforcing member 40 is less likely to deform, and the components located on the inside of the reinforcing member 40 in the vehicle width direction, namely the battery unit 10, can be protected.

[0066] (Third embodiment) Referring to Figure 10, in the side sill reinforcement structure according to the third embodiment, the cross member 32 positioned below the battery case 12 has a mounting portion 32a at its outer end in the vehicle width direction. The mounting portion 32a is a flat plate with its thickness direction oriented vertically and is in surface contact with the lower surface of the fourth lower web 42d that defines the innermost closed cross section 58B. The mounting portion 32a is fixed to the reinforcing member 40 with bolts 60.

[0067] In this configuration as well, if a side impact occurs, the load can be transferred to the cross member 32. This protects the battery unit 10.

[0068] (Fourth Embodiment) Referring to Figure 11, in the side sill reinforcement structure according to the fourth embodiment, the reinforcing member 40 has a protruding closed section portion 58C, similar to the second embodiment. In this embodiment, the protruding closed section portion 58C is trapezoidal in a cross section perpendicular to the vehicle length direction. Thus, the shape of the closed section portion is not limited to a rectangle. The housing portion 14a of the lower case 14 is deeper than in the embodiments described above, and the lower surface of the lower case 14 is at approximately the same height in the vertical direction as the lower surface of the protruding closed section portion 58C.

[0069] In this configuration, when a side impact occurs, the load can be transferred from the innermost closed section 58B and the protruding closed section 58C to the lower case 14 of the battery case 12. Because the lower case 14 is enlarged, the load can be absorbed by the lower case 14, making the reinforcing member 40 less prone to deformation.

[0070] (Fifth embodiment) Referring to Figure 12, in the side sill reinforcement structure according to the fifth embodiment, the lower part of the side sill inner 22 is cut out in an L-shape when viewed from the vehicle length direction. The outermost closed section 58A of the reinforcing member 40 is positioned in this cutout. The bolt 70 is screwed into the side sill inner 22 by passing through the first lower web 42a and the first upper web 41a. The bolt 60 does not reach the floor panel 30, but is screwed into the nut 62 on the flange portions 13b and 14b. Thus, the reinforcing member 40 does not necessarily have to be connected to the lower surface of the side sill 20, nor does it necessarily have to be connected to a vehicle body structure such as the floor panel 30. Referring to Figures 12 and 13, the number of closed sections can be appropriately changed depending on the arrangement space of the reinforcing member 40, and may be three. In this case, the central closed section 52 of the three closed sections 51 to 53 functions as an intermediate closed section 59. The thickness tw2 of the web 44A of the intermediate closed section 59 (second closed section 52) is thicker than the thickness tw1 of the web 43A of the outermost closed section 58A (first closed section 51) and thicker than the thickness tw3 of the web 43B of the innermost closed section 58B (third closed section 53). This provides the same effects as in the above embodiment.

[0071] (Sixth Embodiment) Referring to Figure 14, in the side sill reinforcement structure according to the sixth embodiment, the reinforcing member 40 is located inside the side sill 20. The outermost wall 48A is close to the inner surface of the side sill outer 21, and the innermost wall 48B is close to the inner surface of the side sill inner 22.

[0072] With this configuration, the reinforcing member 40 is placed in the internal space S2 of the side sill 20, so the internal space S2 is effectively utilized and the vehicle side sill structure can be made smaller.

[0073] (modified version) While embodiments have been described above, the above configuration can be modified, added to, or deleted as appropriate within the scope of the present invention.

[0074] For example, the number of closed sections included in the reinforcing member 40 is not particularly limited, and it is sufficient if it is 3 or more.

[0075] The shape of each closed section of the reinforcing member 40 is not limited to rectangles as in the embodiments described above, but may be any polygon (for example, a trapezoid) having a pair of opposing webs and side walls connecting them.

[0076] In the above embodiments, an electric vehicle is used as an example of vehicle 1, but vehicle 1 may also be a gasoline-powered vehicle. In both electric vehicles and gasoline-powered vehicles, the vehicle side sill reinforcement structure of the above embodiments can be suitably applied from the viewpoint of protecting the passenger compartment. [Explanation of Symbols]

[0077] 1 vehicle 10 Battery Units 11 batteries 12 Battery Cases 20 Side sill 21 Side sill outer 22 Side sill inner 30 Floor Panels 31,32 Cross members 32a Mounting part 40 Reinforcement members 40a supporting wall 41 Top Web 42 Lower Web 43A Web defining the outermost closed section 43B Web defining the innermost closed section 44A, 44B Web defining the intermediate closed section 47a~47e Side wall 48A Outermost wall 48B Innermost wall 49A,49B,49C Intermediate side wall 51~54 Closed section 58A Outermost closed section 58B Innermost closed section 58C Protruding closed section 59 Intermediate closed section 59A 1st intermediate closed section 59B 2nd intermediate closed section 60, 70 volts 61 Colors 62 nuts tw1~tw4 Web thickness ts1~ts5 Side wall thickness

Claims

1. A side sill extending in the longitudinal direction on the side of the vehicle, A reinforcing member for the side sill, Equipped with, The reinforcing member has a plurality of closed cross-sectional portions that are connected in the vehicle width direction in a cross-section perpendicular to the vehicle length direction, The plurality of closed cross-sections are defined by a pair of webs arranged opposite each other in the vertical direction and a plurality of side walls arranged at intervals in the vehicle width direction and connecting the pair of webs, The plurality of closed sections include an outermost closed section located on the outermost side in the vehicle width direction, an innermost closed section located on the innermost side in the vehicle width direction, and one or more intermediate closed sections located between the outermost closed section and the innermost closed section. The thickness of the web in the intermediate closed section is greater than the thickness of the web in the outermost closed section, and greater than the thickness of the web in the innermost closed section. Vehicle side sill reinforcement structure.

2. Multiple intermediate closed cross-sections are provided, The thickness of the web in the plurality of intermediate closed sections increases sequentially from the outside to the inside in the vehicle width direction. The vehicle side sill reinforcement structure according to claim 1.

3. Multiple intermediate closed cross-sections are provided, The thickness of the web in the plurality of intermediate closed sections is progressively thinner from the outside to the inside in the vehicle width direction. The vehicle side sill reinforcement structure according to claim 1.

4. The thickness of the web in the innermost closed section is greater than the thickness of the web in the outermost closed section. The vehicle side sill reinforcement structure according to claim 1.

5. The reinforcing member is positioned inside the side sill. A vehicle side sill reinforcement structure according to any one of claims 1 to 4.

6. The reinforcing member is positioned adjacent to the side sill, A vehicle side sill reinforcement structure according to any one of claims 1 to 4.

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