Side beam structure of automobile

Abstract

A side member structure (1) according to the present invention is provided with: an impact-absorbing structure body (20) which is disposed within a side member (10) and which absorbs an impact input to the side member (10) during a side collision of a vehicle, the impact-absorbing structure body (20) having an end section (20a) on the inside of the vehicle in the vehicle width direction connected to a longitudinal surface section (11a) of a side member inner member (11); the impact absorbing structure (20) is provided with a pair of wave-shaped members (21, 23) which are disposed in the vertical direction of the vehicle and which have a wave shape in which convex shapes and concave shapes are alternately continuous in the longitudinal direction of the vehicle, and a concave part (30) which is provided in the vertical surface part (11a) of the side sill inner member (11) and which restricts the end part (20a) on the inside of the vehicle. The impact absorbing structure (20) is provided with: a pair of wave-shaped members (21, 23) which are disposed in the vertical direction of the vehicle; the concave shape (21b) of the upper wave-shaped member (21) and the concave shape (23b) of the lower wave-shaped member (23) are disposed so as to face each other, and the facing concave shapes (21b, 23b) are joined so as to be offset in the longitudinal direction of the vehicle.

Description

Technical Field

[0001] This invention relates to a side sill structure for automobiles that improves crashworthiness by absorbing the impact input during a side crash. Background Technology

[0002] Typically, electric vehicles house the battery module beneath the floor panel between the left and right side beams in the vehicle's width direction. The battery module consists of a battery cell (also called a battery pack) and a battery case for housing the battery cell.

[0003] In the battery box, high-rigidity and high-yield-strength components are used to protect the battery cells from the impact load input during a vehicle collision. Furthermore, components are arranged around the battery box to deform upon impact (load) input to the vehicle during a collision, thereby absorbing crash energy. Especially in side collisions, the side beams deform relative to the load input from the side of the vehicle, absorbing crash energy. Any remaining load not completely absorbed is borne by the floor beams or battery box side beams, thus protecting the battery cells.

[0004] If the deformation required for the side beam to absorb impact energy during a side collision can be reduced, the energy-absorbing portion of the side beam can be reduced in size, resulting in a space-saving side beam structure. In electric vehicles with such a side beam structure, the volume of the battery pack can be increased accordingly to match the reduction in side beam size, thus increasing battery capacity and consequently, driving range. Therefore, electric vehicles require a side beam structure that offers excellent energy absorption performance during side collisions while also saving space.

[0005] To date, several technologies have been proposed to improve the stiffness of side beams and enhance their impact energy absorption performance during side collisions. For example, Patent Document 1 discloses a side component structure (side beam) of a vehicle body equipped with an impact-absorbing component, which is disposed inside a tube extending in the longitudinal direction of the vehicle body and has multiple ridge portions spaced apart from each other in the width direction of the vehicle body. The impact-absorbing component has a wave-like shape that undulates up and down in the longitudinal direction of the vehicle body.

[0006] Patent document 2 discloses a side structure (side beam) of a vehicle body with an impact-absorbing component, which is disposed inside a cylindrical body extending in the front-rear direction of the vehicle body and has a wavy plate, i.e., a web plate, that alternately folds up and down in the front-rear direction.

[0007] Patent documents 3 and 4 disclose a vehicle body structure having a reinforcing member constituting at least a portion of a continuous cylindrical structure formed inside a side beam, the continuous cylindrical structure having a shape formed by connecting multiple polygonal closed cross sections when viewed from the vehicle width direction.

[0008] Patent document 5 discloses a vehicle body structure in which a wave-shaped plate, i.e. an energy absorption component, is arranged and fixed in the side beam, extending along the width direction and repeatedly bending or folding up and down.

[0009] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2021-146973 Patent Document 2: Japanese Patent No. 7095821 Patent Document 3: Japanese Patent Application Publication No. 2020-111267 Patent Document 4: Japanese Patent Application Publication No. 2021-024350 Patent Document 5: Japanese Patent Application Publication No. 2023-056569 Summary of the Invention

[0010] The problem that the invention aims to solve According to Patent Document 1, even in a side pole crash, the entire impact-absorbing component can efficiently absorb a large local impact energy (equivalent to the "collision energy" of this application; the same applies hereinafter). Furthermore, according to Patent Document 2, even when the impact load acts in the vehicle width direction, the impact energy (equivalent to the collision energy of this application) can be efficiently absorbed, and deformation towards the inward side of the vehicle can be suppressed, effectively protecting the battery pack housing the battery box. However, in the technologies disclosed in Patent Documents 1 and 2, the wave-shaped impact-absorbing component is constructed from a single metal plate, resulting in low rigidity. Under impact loads, it is prone to deformation where the wave-shaped opening opens along the vehicle's length direction. Moreover, when this deformation occurs, the crash energy absorption characteristics decrease.

[0011] According to Patent Document 3, side-impact performance can be improved by appropriately configuring a stiffened member inside the side beam to increase the reaction force of the stiffened member. However, in a side impact, since the continuous cylindrical structure is a structure that extends and retracts in the longitudinal direction of the vehicle body, it is deformed by the force that extends in the longitudinal direction of the vehicle body, which may prevent the expected reaction force of the stiffened member from being ensured.

[0012] According to Patent Document 4, by including a deformation control component that suppresses deformation of the continuous cylindrical structure in the longitudinal direction, compared to the vehicle body structure described in Patent Document 3, the deformation of the continuous cylindrical structure in the longitudinal direction during a side impact can be limited. Furthermore, it is expected that the reaction force of the reinforcing component can be improved, thereby enhancing collision energy absorption performance. However, because the vehicle body structure described in Patent Document 4 includes the deformation control component, the number of components increases, and the weight of the components also increases.

[0013] According to Patent Document 5, when a collision load is applied during a side impact, the energy-absorbing component inside the side beam is easily crushed, effectively absorbing the collision energy. However, when the energy-absorbing component is designed as a joint of two metal plates, a polygonal shape and a jointed portion are created, but these differ in rigidity, resulting in variations in collision performance depending on the impact location. Furthermore, increasing the rigidity of the jointed portion is effective in reducing these differences in collision performance, but this requires increasing the plate thickness, thus increasing weight.

[0014] Furthermore, in the technology disclosed in Patent Document 5, when using extruded material to manufacture polygonal parts, a method is employed to gradually change the cross-sectional area in the collision direction and to induce buckling by forming reinforcing ribs perpendicular to the collision direction in order to achieve stable buckling during impact. However, since the cross-section of the extruded material is constant in the extrusion direction, it is extremely difficult to gradually change the cross-sectional area. In addition, when forming reinforcing ribs, there is a problem of increased manufacturing costs due to the increased number of processes.

[0015] The present invention was made to solve the above-mentioned problems, and its purpose is to provide a side beam structure for automobiles that improves the impact performance in side collisions without increasing weight and manufacturing costs.

[0016] Methods for solving problems The side beam structure of an automobile according to the present invention comprises a side beam having an inner side beam and an outer side beam. The inner side beam extends along the length direction of the vehicle and has a groove shape with an opening to the outer side of the vehicle in the width direction. The outer side beam extends along the length direction of the vehicle and has a groove shape with an opening to the inner side of the vehicle in the width direction. The inner and outer side beams are joined together with their opening sides facing each other. The side beam structure of the automobile includes: an impact absorbing structure disposed within the side beam, wherein the inner end in the width direction is connected to the bottom of the groove shape of the inner side beam and / or the outer end in the width direction is connected to the bottom of the groove shape of the outer side beam. The impact absorbing structure absorbs the impact input to the side beam during a side collision of the vehicle; and a vertical restraint structure. The structure is located at the bottom of the aforementioned side beam inner member and constrains the aforementioned end of the inner side of the vehicle in the vertical direction of the vehicle during a side collision. The aforementioned impact-absorbing structure has a pair of wave-shaped components. The aforementioned pair of wave-shaped components have a wave shape in which convex and concave shapes alternate continuously in the vehicle length direction in a cross section orthogonal to the vehicle width direction, and are arranged in the vertical direction of the vehicle. The aforementioned pair of wave-shaped components are made of metal plates. The aforementioned concave shape of the upper wave-shaped component and the aforementioned concave shape of the lower wave-shaped component are arranged opposite to each other and are joined in a state where the relative concave shapes are misaligned in the vehicle length direction.

[0017] It is possible that the aforementioned upper and lower constraint structure is a recessed part of the aforementioned groove shape in the aforementioned side beam inner member, which is recessed towards the vehicle width direction, and the aforementioned end of the aforementioned impact absorbing structure on the vehicle inner side is inserted into the aforementioned recessed part.

[0018] It is possible that the front end of the aforementioned impact-absorbing structure on the outer side of the vehicle in the vehicle width direction contacts the aforementioned bottom of the aforementioned groove shape in the aforementioned side beam outer member.

[0019] It is possible that the misalignment W2 of the aforementioned concave shape in the upper and lower wave-shaped components in the vehicle length direction is more than 20% and less than 50% of the center distance W1 between the aforementioned convex shape and the aforementioned concave shape adjacent in the vehicle length direction in the aforementioned wave-shaped components.

[0020] It is possible that the recessed amount D of the aforementioned recess in the aforementioned side beam inner member is more than 0.8 times and less than 1.2 times the height h of the aforementioned impact absorbing structure in the vehicle vertical direction.

[0021] Yes, the aforementioned corrugated component is a metal plate component with a tensile strength of 590 MPa or higher.

[0022] Invention Effects According to the present invention, the buckling resistance to impact loads input to the side beam during a side collision can be improved, and the impact-absorbing structure can be crushed while maintaining high deformation resistance. Furthermore, the amount of deformation in the vehicle width direction can be reduced, and high collision energy absorption characteristics are obtained. Additionally, by aligning the concave shapes of the upper and lower wave-shaped members in the impact-absorbing structure with each other in a non-linearly symmetrical manner with a misalignment in the vehicle length direction, the positions of the convex and concave edges of each wave-shaped member in the vehicle length direction can be dispersed. Furthermore, the buckling load (peak load) during a side collision can be suppressed to a lower level, making it less likely for differences (deviations) in collision performance caused by different locations of the input impact load to occur. Furthermore, when the present invention is applied to electric vehicles, the space required to absorb collision energy can be reduced, thus allowing for a larger volume of the battery pack mounted in the electric vehicle. Moreover, since the impact-absorbing structure of the present invention has high bending stiffness, it is not necessary to increase the plate thickness to improve stiffness, thereby also suppressing the increase in vehicle body weight. Attached Figure Description

[0023] Figure 1 The figure shows an example of the configuration of the side beam structure according to an embodiment of the present invention ((a) is a cross-sectional view orthogonal to the vehicle length direction, and (b) is a cross-sectional view orthogonal to the vehicle width direction).

[0024] Figure 2 This is a graph illustrating the ideal load-stroke curve of the side beam structure during a side collision of a vehicle (solid line: load-stroke curve in conventional side beam structures, dashed line: ideal load-stroke curve).

[0025] Figure 3 This is an unfolded view of the impact-absorbing structure of the side beam structure according to an embodiment of the present invention.

[0026] Figure 4 This is a diagram illustrating the misalignment W2 in the vehicle length direction between the wave-shaped component on the upper side and the wave-shaped component on the lower side of the side beam structure in the side beam structure according to an embodiment of the present invention.

[0027] Figure 5This is a diagram illustrating an example of a vehicle side structure with a side beam structure according to an embodiment of the present invention.

[0028] Figure 6 This is a diagram illustrating a modified example of an upper and lower constraint structure in the side beam structure according to an embodiment of the present invention, which constrains the inner end of the impact-absorbing structure in the vertical direction of the vehicle.

[0029] Figure 7 This is a diagram illustrating a support structure for supporting an impact-absorbing structure disposed within a side beam in an embodiment of the present invention.

[0030] Figure 8 This is a diagram illustrating the test subject used as the analysis object in the side-impact collision test of a simulated vehicle in Example 1.

[0031] Figure 9 This is a diagram showing the side beam structure used as the test object in a side-impact collision test of a simulated vehicle in Embodiment 1.

[0032] Figure 10 The figure shows the deformation state of the impact-absorbing structure in the collision analysis of a simulated side collision of a vehicle in Embodiment 1 ((a) is a top view of the impact-absorbing structure, (b) is a perspective view of the impact-absorbing structure viewed from the outside of the vehicle, and (c) is a cross-sectional view of the side beam structure).

[0033] Figure 11 This is a diagram illustrating the deformation behavior of the impact-absorbing structure in the collision analysis of a simulated side-impact collision of a vehicle in Example 1.

[0034] Figure 12 This is a graph showing the relationship between the collision energy absorbed by the side beam structure and the maximum load input to the side beam structure during the side impact test in Example 1.

[0035] Figure 13 The following is a cross-sectional view of the impact-absorbing structure that was the subject of the side-impact collision test in Example 2 ((a) is Example 3, (b) are Comparative Examples 6 and 7, and (c) is Comparative Example 8).

[0036] Figure 14 This is a cross-sectional view showing the deformation behavior of the side beam structure during a side collision in Embodiment 2 ((a) is the side beam structure involved in Invention Example 3, and (b) is the side beam structure involved in Comparative Example 6).

[0037] Figure 15 It is the load-stroke curve obtained by crashworthiness analysis in the side impact test of the test body involved in Example 3 and Comparative Example 6 of Example 2.

[0038] Figure 16 The graph shows the (a) load-stroke curve and (b) the shift of collision absorbed energy obtained by collision analysis in the side impact test of the test objects involved in Example 3, Comparative Example 7 and Comparative Example 8 of Example 2. Detailed Implementation

[0039] <The Invention Process> The technologies described in the aforementioned patent documents 1 to 5 all involve assembling a wave-shaped component within the side beam. This wave shape is formed by repeating a shape that is bent or folded along the vertical direction of the vehicle along the length direction of the vehicle (Patent documents 1 and 2: impact absorption component; Patent documents 3 and 4: reinforcement component; Patent document 5: energy absorption component). Hereinafter, the structure in which a wave-shaped component is arranged within the side beam will be referred to as a "conventional side beam structure".

[0040] Typically, in the case of a side beam structure, the load (impact load) input to the side beam during a side collision is transferred to high-yield strength members such as crossbeams located on the inner side of the vehicle. The reaction force from these high-yield strength members crushes the side beam structure, absorbing the collision energy. Furthermore, in the conventional process of side beam structure crushing, the wave-shaped components within the side beam oscillate with multiple antinodes, generating bellows-shaped buckling deformation. In the following explanation, this lantern-shaped buckling deformation will also be referred to as the "lantern-shaped buckling mode" or "axial crash mode."

[0041] exist Figure 2 The figure shows a load-stroke curve, which schematically illustrates the relationship between the load input to the side beam and the amount of intrusion of the impactor into the vehicle, i.e., the stroke, when a colliding body collides with the side of a conventional side beam structure that has a wave-shaped component disposed in the side beam during a side collision.

[0042] Figure 2 In the figure shown, the load on the vertical axis is the contact reaction force from load-bearing components such as crossbeams. The value obtained by integrating the load with the stroke (the amount of deformation of the side beam structure in the vehicle width direction), i.e., the area enclosed by the load-stroke curve, represents the amount of collision energy absorbed.

[0043] Previous side beam structures, such as Figure 2As shown by the solid line in the load-stroke curve, after elastic deformation, the ridges in the wave-shaped component exhibit lantern-shaped buckling deformation (lantern buckling mode), and the load continues to increase with the increase of stroke.

[0044] Typically, allowable loads (bending resistance Fa) are set for load-bearing components such as crossbeams. Therefore, in order to protect the battery box through load-bearing components during side impacts, such as… Figure 2 As shown by the solid line load-stroke curve, the maximum load (Fmax) needs to be below the allowable load (Fa).

[0045] Therefore, in conventional side beam structures, to ensure that the maximum load (Fmax) is below the allowable load (Fa) of the load-bearing component, the thickness and material (e.g., yield stress) of the metal plate constituting the corrugated component need to be set in a way that allows the corrugated component to buckle under a buckling load (Fb) below the maximum load (Fmax). Thus, in a side beam structure with corrugated components, to achieve the desired amount of impact energy absorption during a side collision, the deformation of the side beam needs to be controlled (…). Figure 2 The structure added in S1).

[0046] On the other hand, in electric vehicles, to increase the volume of the battery pack, it is necessary to reduce the deformation of the side beams required to absorb a specified amount of collision energy through the side beam structure. Therefore, the inventors believe that, in order to reduce the stroke while ensuring the same amount of collision energy absorption as conventional side beam structures, it is only necessary to set it to achieve... Figure 2 The ideal load-stroke curve shown by the dashed line is sufficient for the side beam structure.

[0047] Figure 2 The ideal load-stroke curve shown accelerates the increase of load generated in the side beam during a side impact by increasing the rigidity of the side beam structure, and increases the buckling load to the maximum load (Fmax) level of previous side beam structures, while suppressing the increase of load during the impact process after buckling deformation, keeping the load constant. In a side beam structure that can achieve such a load-stroke curve, it is considered that the necessary impact energy absorption can be ensured, and the deformation of the side beam can be reduced. Figure 2 (S2 in the middle).

[0048] Then, the inventors were able to achieve Figure 2 The specific structure of the side beam structure with the ideal load-stroke curve shown was studied. The rigidity and buckling load of the side beam structure can be adjusted by appropriately selecting the plate thickness and material of the wave-shaped components installed in the side beam. However, by simply selecting the plate thickness and material, it is impossible to suppress the increase of load during the collision process after buckling deformation and maintain it constant.

[0049] Therefore, the inventors conducted repeated research to solve this problem. In this research, the inventors focused on the main reason why the load gradually increases after the initial buckling deformation in conventional side beam structures. The results suggest that in conventional side beam structures, during the intrusion of a colliding object into the vehicle's interior, after the initial buckling deformation occurs at the outer end of the wave-shaped component installed in the side beam, corrugated buckling deformation continues to occur from the outer side of the vehicle towards the inner side, oscillating with multiple antinodes, thereby increasing the load.

[0050] Therefore, in order to achieve Figure 2 The ideal load-stroke curve shown is conceived of suppressing the buckling deformation of the wave-shaped component disposed in the side beam after the initial buckling deformation, which is continuously generated in a corrugated manner while oscillating in a manner with multiple antinodes.

[0051] Furthermore, it was discovered that by making the wave-shaped components within the side beam asymmetrically opposite and joined in a misaligned state along the vehicle's length direction, it is possible to suppress the initial buckling deformation of the wave-shaped components, which then continuously produces a corrugated shape while oscillating in a manner with multiple antinodes, and to push the buckling deformation away with a constant load.

[0052] This led to the following insights: Compared to conventional side beam structures, by appropriately selecting plate thickness and material to improve rigidity, the maximum load can be increased. Furthermore, by ensuring a constant load shift after buckling, deformation can be reduced while ensuring necessary impact energy, thus achieving a compact side beam structure. This invention is based on the above insights, and its structure is described below.

[0053] <Car side beam structure> like Figure 1 As an example, the side beam structure 1 according to the embodiment of the present invention includes a side beam 10 having an inner side beam member 11 and an outer side beam member 13, an impact-absorbing structure 20, and a recess 30. Hereinafter, each component of the side beam structure 1 will be described. In this application, terms related to direction such as "vehicle length direction," "vehicle width direction," and "vehicle vertical direction," and terms related to position such as "outer side of vehicle," "inner side of vehicle," "upper side of vehicle," and "lower side of vehicle," indicate the direction and position of the side beam structure 1 in the actual state of the vehicle.

[0054] Side Beam like Figure 1 As shown, the side beam 10 is formed by joining the inner side beam member 11 and the outer side beam member 13.

[0055] The side beam inner member 11 has a longitudinal portion 11a that is substantially parallel to the vertical direction of the vehicle, and a pair of transverse portions 11b that extend continuously outward from the upper and lower ends of the longitudinal portion 11a, respectively. In the side beam inner member 11, the longitudinal portion 11a and the pair of transverse portions 11b form a groove shape, with the longitudinal portion 11a corresponding to the bottom of the groove shape. Furthermore, the side beam inner member 11 has flange portions 11c that extend from the ends of the transverse portions 11b on the upper and lower sides of the vehicle, respectively, towards the upper and lower sides of the vehicle.

[0056] The side beam outer member 13 has a longitudinal portion 13a that is substantially parallel to the vertical direction of the vehicle, and a pair of transverse portions 13b that extend continuously from the upper and lower ends of the longitudinal portion 13a toward the inward side of the vehicle. In the side beam outer member 13, the longitudinal portion 13a and the pair of transverse portions 13b form a groove shape, with the longitudinal portion 13a corresponding to the bottom of the groove shape. In addition, the side beam outer member 13 has flange portions 13c that extend from the ends of the transverse portions 13b on the upper and lower sides of the vehicle toward the upper and lower sides of the vehicle, respectively.

[0057] Furthermore, the slot-shaped opening sides of the inner member 11 and the outer member 13 of the side beam are made to face each other, and the flange portion 11c and the flange portion 13c are joined together (e.g., by spot welding). Thus, a side beam 10 with a closed cross-sectional space 10a inside is formed.

[0058] The longitudinal facet 11a of the inner side beam member 11 and the longitudinal facet 13a of the outer side beam member 13 may not be planar shapes parallel to the vertical direction of the vehicle; they may be inclined relative to the vertical direction of the vehicle or have a curved shape. Similarly, the transverse facet 11b of the inner side beam member 11 and the transverse facet 13b of the outer side beam member 13 may not be planar shapes parallel to the horizontal plane; they may be inclined relative to the horizontal plane or have a curved shape.

[0059] Impact Absorbing Structure Regarding the impact-absorbing structure 20, the inner end 20a in the vehicle width direction is connected to the bottom of the groove-shaped section, i.e., the longitudinal surface 11a, in the side beam inner member 11, and will absorb the impact input to the side beam 10 during a side collision of the vehicle. Furthermore, as... Figure 1 and Figure 3As shown, the impact-absorbing structure 20 includes a pair of wave-shaped components 21 and 23. These wave-shaped components 21 and 23 have alternating convex and concave shapes in a cross-section orthogonal to the vehicle width direction, and are disposed in the vertical direction of the vehicle. The upper wave-shaped component 21 has alternating convex shapes 21a and concave shapes 21b in a cross-section orthogonal to the vehicle width direction, with continuous convex shapes 21a and 21b in the vehicle length direction. Similarly, the lower wave-shaped component 23 has alternating convex shapes 23a and concave shapes 23b in a cross-section orthogonal to the vehicle width direction, with continuous convex shapes 23a and 23b in the vehicle length direction. In the upper wave-shaped component 21 and the lower wave-shaped component 23, the convex shapes 21a and 23a are formed by a top surface and a pair of continuous walls from both ends, and the concave shapes 21b and 23b are formed by a bottom surface and a pair of continuous walls from both ends.

[0060] The pair of wave-shaped components 21 and 23 are made of metal sheet. Furthermore, in the impact-absorbing structure 20, the upper wave-shaped component 21 and the lower wave-shaped component 23 are arranged such that the concave shape 21b of the upper wave-shaped component 21 faces the concave shape 23b of the lower wave-shaped component. Moreover, the bottom surfaces of the concave shapes 21b and 23b are joined together in a state where the opposing concave shapes 21b and 23b are misaligned in the vehicle's length direction. The arrangement of the concave shape 21b of the upper wave-shaped component 21 facing the concave shape 23b of the lower wave-shaped component means that the upper wave-shaped component 21 and the lower wave-shaped component 23 are arranged in a state of vertical flipping.

[0061] In the impact-absorbing structure 20, such as Figure 4 As shown, the misalignment of concave shapes 21b and 23b in the vehicle length direction refers to the state in which the center positions of the bottom surfaces of concave shapes 21b and 23b are misaligned by a predetermined misalignment amount W2 in the vehicle length direction. Furthermore, the bottom surfaces of concave shapes 21b and 23b can be joined, for example, by spot welding. Thus, the impact-absorbing structure 20 has a structure that is integrated within the side beam 10 and comprises a pair of upper and lower corrugated components 21 and 23.

[0062] Furthermore, in this embodiment, the front end of the impact-absorbing structure 20 on the outer side of the vehicle in the vehicle width direction contacts the longitudinal face 13a of the groove-shaped part 13 in the outer member 13 of the side beam. The front end of the impact-absorbing structure 20 on the outer side of the vehicle refers to the end face of the metal plate used for the corrugated members 21 and 23.

[0063] As will be described later Figure 5As shown, the impact-absorbing structure 20 is preferably configured to coincide with the vertical position of the floor beam 103 within the side beam 10. This allows it to absorb the impact input to the side beam 10 during a side collision, and enables the load to be transferred to the floor beam 103, utilizing its reaction force to efficiently crush the impact-absorbing structure 20, thereby increasing the amount of collision energy absorbed.

[0064] ≪Concave≫ The recess 30 serves as a vertical constraint structure that constrains the inner end 20a of the impact-absorbing structure 20 in the vertical direction of the vehicle. It is located at the bottom of the groove-shaped section of the side beam inner member 11, i.e., the longitudinal surface 11a. Furthermore, the recess 30 inserts into the inner end 20a of the impact-absorbing structure 20, and during a side collision, it presses against the end 20a in the vertical direction of the vehicle, thereby preventing the end 20a from shifting vertically. The inner end 20a of the impact-absorbing structure 20 inserted into the recess 30 engages with the bottom 31 of the recess 30.

[0065] Reference Figure 1 (a) and Figure 3 An example of the joining method between the inner end 20a of the impact-absorbing structure 20 and the longitudinal face 11a of the side beam inner member 11 will be described.

[0066] Regarding the impact-absorbing structure 20, its inner end 20a in the vehicle width direction is inserted into the recess 30 of the longitudinal surface 11a of the side beam inner member 11. Furthermore, the end 20a is joined (spot welded, etc.) to the bottom 31 of the recess 30 via a flange portion 25 provided at the front end of the end 20a. The flange portion 25 may be provided along the entire length of the vehicle or may be provided intermittently in the length of the vehicle.

[0067] The following is based on Figure 5 The vehicle side structure 100 shown illustrates the effect of the side beam structure 1 according to the embodiment of the present invention.

[0068] ≪Vehicle Side Structure≫ The floor crossbeam 103 is a body frame structural component disposed above the floor plate 101 and extending along the vehicle width direction. Each end 103a in the vehicle width direction is joined (e.g., by spot welding) to the bottom of the groove shape of the side beam inner member 11, i.e., the longitudinal surface 11a. Multiple floor crossbeams 103 are provided at predetermined intervals (e.g., about 300 mm) in the vehicle length direction.

[0069] The battery box 105 is disposed below the base plate 101 and houses the battery pack 107 inside. Each side portion 105a of the battery box 105 in the vehicle width direction faces the side beam inner member 11 at a predetermined interval. In the vehicle side structure 100, the side portion 105a of the battery box 105 faces the lower part of the longitudinal portion 11a of the side beam inner member 11.

[0070] Additionally, a mounting flange 105c is provided at the bottom of the battery box 105, i.e., the base plate 105b, in a manner that protrudes toward the side beam 10. Furthermore, the mounting flange 105c is fastened to the lower transverse portion 11b of the inner member 11 of the side beam using fixing bolts 109, thereby holding the battery box 105 to the side beam 10.

[0071] The impact-absorbing structure 20, which is installed inside the side beam structure 1, is configured to overlap with the floor beam 103 in the vehicle height direction when viewed from the side in the vehicle width direction.

[0072] ≪Effects of Side Beam Structure 1≫ In the side beam structure 1 of this embodiment, the impact absorbing structure 20 disposed in the side beam 10 is formed by joining the bottom surfaces of the concave shape 21b of the upper wave-shaped component 21 and the concave shape 23b of the lower wave-shaped component 23 in a state of misalignment in the vehicle length direction and non-linear symmetry.

[0073] Figure 1 In the cross-sectional view of the impact-absorbing structure 20 shown in (b) orthogonal to the vehicle width direction, the edges (corners) of the convex shapes 21a and 23a and the concave shapes 21b and 23b have high deformation resistance relative to the collision load from the outer side of the vehicle in the vehicle width direction. Furthermore, the top surface sandwiched between the edges of the convex shapes 21a and 23a, with a long interval between the edges (…),… Figure 1 The position of the dashed ellipse in (b) and the wall with short intervals between the edges ( Figure 1 Compared to the position of the solid-line ellipse in (b), the deformation resistance is relatively low. Furthermore, the upper wave-shaped member 21 and the lower wave-shaped member 23 in the impact-absorbing structure 20 are misaligned and joined relative to each other in the vehicle length direction. Thus, as... Figure 1 As shown in (b), in a cross section orthogonal to the vehicle width direction, the part with relatively high deformation resistance (solid ellipse) and the part with relatively low deformation resistance (dashed ellipse) are positioned vertically opposite each other in the vehicle length direction, and the upper wave-shaped component 21 and the lower wave-shaped component 23 are intermittently generated in the vehicle length direction, with different deformation resistances at the top and bottom.

[0074] Therefore, in a side collision involving a vehicle equipped with side beam structure 1, as described later... Figure 10As shown in (c), due to the different deformation resistance of the upper corrugated member 21 and the lower corrugated member 23 at the position along the vehicle's length direction after the side impact of the colliding body, a rotational moment is generated around the axis along the vehicle's length direction, resulting in initial buckling deformation, such as out-of-plane bending in the direction of rotation, at both ends on the inner and outer sides of the vehicle. Furthermore, since the impact-absorbing structure 20 is inclined relative to the horizontal plane in the vehicle's width direction, after the initial buckling deformation, it does not develop into a corrugated buckling deformation, but rather becomes a deformation pattern where the buckling deformation continues at the positions of the corrugated members 21 and 23 at both ends. In this way, the side beam structure 1 according to this embodiment can suppress the aforementioned... Figure 2 As shown, the increase in load accompanying the increase in stroke (deformation) allows for displacement with a load approximately equal to the maximum load.

[0075] Furthermore, the impact-absorbing structure 20 has a structure in which the wave-shaped component 21 and wave-shaped component 23 are integrated within the side beam 10. Therefore, in the impact-absorbing structure 20, the closed cross-sectional space formed by the convex shape 21a of the upper wave-shaped component 21 and the convex shape 23a of the lower wave-shaped component 23 is continuously arranged at constant intervals along the vehicle's length direction. Thus, the impact-absorbing structure 20 as a whole has high bending stiffness (resistance to bending deformation under side impact loads). This suppresses local deformation of the impact-absorbing structure 20 around the area where the impact load is applied in the side beam, causing buckling deformation around the area where the impact load is applied, thereby increasing the amount of impact energy absorbed.

[0076] Furthermore, in the side beam structure 1, a recess 30 is provided at the bottom of the groove shape, i.e., the longitudinal face 11a, in the side beam inner member 11. The inner end 20a of the impact-absorbing structure 20 is inserted into the recess 30, constraining it in the vertical direction of the vehicle. Thus, in the event of a side collision, the inner end 20a of the impact-absorbing structure 20 is prevented from shifting in the vertical direction, thus preventing the impact-absorbing structure 20 from tipping over, or the end 20a from deforming significantly in the out-of-plane direction. As a result, the reduction in collision energy absorption caused by the tipping of the impact-absorbing structure 20 and the out-of-plane deformation of the end 20a can be suppressed.

[0077] Furthermore, the impact-absorbing structure 20 is configured such that the floor beam 103 overlaps with the vehicle height direction when viewed from the side in the vehicle width direction. Thus, collision loads input from the outside of the vehicle to the outer member 13 of the side beam are transferred to rigid components such as the floor beam via the impact-absorbing structure 20, and the reaction forces from the rigid components are transferred to the impact-absorbing structure 20 via the inner member 11 of the side beam. This effectively crushes the impact-absorbing structure 20, thereby improving its collision energy absorption performance.

[0078] In the side beam structure 1 described in this embodiment, the buckling resistance to impact loads input to the side beam 10 during a side collision can be improved, and the impact absorption structure 20 can be crushed while maintaining high deformation resistance, thus achieving high collision energy absorption performance.

[0079] Furthermore, in the impact-absorbing structure 20, the concave shape 21b of the upper wave-shaped member 21 and the concave shape 23b of the lower wave-shaped member 23 are arranged opposite each other, and the opposing concave shapes 21b and 23b are joined in a misaligned state in the vehicle length direction. As a result, the positions of the ridges of the convex shapes 21a and 23a and the ridges of the concave shapes 21b and 23b in the vehicle length direction are dispersed, thus making it less likely for differences (deviations) in collision performance to occur due to different positions of the input impact load.

[0080] Furthermore, when the side beam structure 1 is applied to an electric vehicle, the space required to absorb collision energy within the side beam structure 1 can be reduced. Therefore, the volume of the battery pack disposed between the side beams 10 on both sides in the vehicle width direction can also be increased.

[0081] Furthermore, in the side beam structure 1 of this embodiment, the impact absorbing structure 20 has high bending stiffness, so it is not necessary to increase the thickness of the metal plate used in the side beam structure 1 in order to improve the stiffness, and the increase in vehicle weight can also be suppressed.

[0082] In the side beam structure 1 of this embodiment, a recess 30 is provided on the longitudinal surface 11a of the side beam inner member 11 as a vertical constraint structure that constrains the inner end 20a of the impact absorption structure 20 in the vertical direction of the vehicle.

[0083] However, in this invention, the upper and lower constraint structures are not limited to the recess 30. Figure 6 The image shows a variation of the upper and lower constraint structure. Figure 6 In the side beam structure 1 shown, as an upper and lower constraint structure, L-shaped brackets 35 are provided above and below the inner end 20a of the impact-absorbing structure 20. The upper L-shaped bracket 35 engages with the top surface of the upper corrugated member 21 and the longitudinal surface 11a of the inner member 11 of the side beam, while the lower L-shaped bracket 35 engages with the lower surface of the lower corrugated member 23 and the longitudinal surface 11a of the inner member 11 of the side beam. The L-shaped bracket 35 can be joined to the corrugated members 21 and 23 and the longitudinal surface 11a by spot welding or the like.

[0084] In this way, the side beam structure 1 with the L-shaped bracket 35 as the upper and lower constraint structure can also constrain the inner end 20a of the impact absorption structure 20 in the vertical direction of the vehicle during a side collision.

[0085] The L-shaped bracket 35 is not limited to being installed along the entire length of the vehicle, as long as it can restrain the inner end 20a of the vehicle in the vertical direction during a side collision. It can also be installed intermittently along the length of the vehicle.

[0086] Furthermore, the present invention is not limited to, for example Figure 1 or Figure 6 The side beam structure 1 shown, namely, the inner end 20a of the impact-absorbing structure 20, is joined to the longitudinal surface 11a of the inner member 11 of the side beam. That is, the present invention may also omit the flange portion at the inner end of the impact-absorbing structure, and instead, the front end of the inner side is the end face of the metal plate constituting the corrugated component, and it contacts the longitudinal surface of the inner member of the side beam in an abutting manner.

[0087] However, as Figure 1 As shown, the inner end 20a of the impact-absorbing structure 20 is connected to the longitudinal face 11a in the side beam inner member 11, thereby providing good impact energy absorption performance during side collisions, which is preferred.

[0088] Alternatively, the present invention may also involve connecting the outer end 20b of the impact-absorbing structure 20 to the longitudinal surface 13a of the side beam outer member 13. As a method of connecting the outer end 20b of the impact-absorbing structure 20 to the longitudinal surface 13a of the side beam outer member 13, for example, a flange portion bent from the front end of the outer end can be provided and joined (spot welded, etc.) to the longitudinal surface of the side beam outer member.

[0089] However, when the impact-absorbing structure has a flange at its outer end connected to the side beam outer member via a folded portion that bends along the vertical direction of the vehicle with a specified curvature radius, the rigidity against loads input during side collisions sometimes decreases. Therefore, as... Figure 1 As shown, the impact-absorbing structure 20 preferably does not have a flange at its outer end, but rather its front end abuts against the longitudinal surface 13a of the side beam outer member 13. Therefore, the impact-absorbing structure 20 can withstand the load input to the side beam 10 without reducing its rigidity, thus accelerating the load rise during the initial stage of a collision and increasing the amount of collision energy absorbed.

[0090] In the impact-absorbing structure 20, either the upper corrugated component 21 or the lower corrugated component 23, or either the upper or lower corrugated component 21 or 23, may come into contact with the longitudinal face 11a of the inner member 11 of the side beam and / or the longitudinal face 13a of the outer member 13 of the side beam in an abutting manner.

[0091] The present invention does not exclude the provision of a gap between the outer end 20b of the impact-absorbing structure 20 and the outer member 13 of the side beam, or between the inner end 20a of the impact-absorbing structure 20 and the inner member 11 of the side beam. That is, the impact-absorbing structure 20 can be supported within the side beam 10 simply by connecting the inner end 20a of the impact-absorbing structure 20 to the longitudinal surface 11a of the inner member 11 of the side beam, or by connecting the outer end 20b of the impact-absorbing structure 20 to the longitudinal surface 13a of the outer member 13 of the side beam.

[0092] Furthermore, in the side beam structure 1 of this embodiment, as described above, the upper corrugated member 21 and the lower corrugated member 23 are joined together by means of opposite concave shapes 21b and 23b being misaligned in the vehicle length direction. Moreover, the amount of misalignment of the concave shapes 21b and 23b in the vehicle length direction can be determined in such a way that the bottom surfaces can join together.

[0093] Figure 4 The diagram shows the misalignment between the concave shape 21b of the upper wave-shaped component and the concave shape 23b of the lower wave-shaped component 23. In the wave-shaped component 21, the distance between the centers of adjacent convex shapes 21a and concave shapes 21b along the vehicle's length direction is (…). Figure 4 The distance between the dotted lines passing through the ● is set as W1. Furthermore, when the misalignment amount (the distance between the centers of the concave shapes) between the concave shape 21b of the upper wave-shaped member 21 and the concave shape 23b of the lower wave-shaped member 23 is set as W2, the misalignment amount W2 is preferably more than 20% and less than 50% of W1 (0.2×W1≤W2≤0.5×W1).

[0094] When the misalignment W2 is less than 20% of W1 (W2 < 0.2 × W1), the buckling deformation of the edge of the upper corrugated member 21 and the edge of the lower corrugated member 23 occurs almost simultaneously. Therefore, it becomes an axial crushing mode in which corrugated buckling deformation occurs in both corrugated members 21 and 23, and the effect of suppressing the increase of load during the collision process after buckling deformation is small. In addition, when the misalignment W2 exceeds 50% of W1 (W1 > 0.5 × W1), the overlap range between the bottom surfaces of concave shapes 21b and 23b is narrow, making it difficult to join them by spot welding or the like.

[0095] The recess 30 has the function of suppressing the misalignment of the inner end 20a in the vertical direction of the vehicle during the deformation of the impact-absorbing structure 20 in a side collision. Therefore, the amount of recess D inward of the recess 30 is set to be sufficient to perform this function. Therefore, the amount of recess D in the recess 30 is preferably 0.8 to 1.2 times the height h of the impact-absorbing structure 20 in the vertical direction of the vehicle. The height h of the impact-absorbing structure 20 in the vertical direction of the vehicle refers to the height of the pair of wave-shaped members 21 and 23 arranged side by side in the vertical direction of the vehicle.

[0096] When the indentation D of the recess 30 is less than 0.8 times the height h of the impact-absorbing structure 20, during a side collision, as the cross-section of the side beam 10 opens vertically and collapses (cross-section collapsing), the recess 30 also deforms vertically, causing the inner end 20a of the impact-absorbing structure 20 to detach from the recess 30. Furthermore, when the indentation D of the recess 30 exceeds 1.2 times the height h, the recess 30 interferes with the floor crossbeam, battery pack, etc., located on the inner side of the side beam inner member 11, potentially requiring significant modifications to the structure of the floor crossbeam and battery pack.

[0097] Furthermore, if a flange 25 is provided at the end 20a on the inner side of the impact-absorbing structure 20 and the flange 25 is spot-welded to the bottom 31 of the recess 30, the height of the recess 30 in the vertical direction of the vehicle can be set to a level that ensures sufficient working space for welding the flange 25. Based on the above, the height H of the recess 30 in the vertical direction of the vehicle is preferably set to the height h of the impact-absorbing structure 20 (refer to...). Figure 1 1.3 to 1.4 times that of (a) in the middle.

[0098] The tensile strength of the metal plate used for the impact-absorbing structure 20 is preferably 590 MPa or higher. Regarding the crash worthiness of the impact-absorbing structure 20, during a side impact, the higher the load (bending resistance) at which the impact-absorbing structure 20 initially deforms and then transitions from elastic deformation to plastic deformation, the less likely it is to bend, resulting in better crash worthiness. The higher the tensile strength (yield strength) of the metal plate used for the impact-absorbing structure 20, the higher the bending resistance; therefore, a metal plate with a tensile strength of 590 MPa or higher, which is higher than that of common steel, is preferred.

[0099] Furthermore, when a high-tensile steel sheet is used in the impact-absorbing structure 20, the impact-absorbing structure 20 disposed within the side beam 10 also functions as a reinforcement of the side beam 10. Therefore, the metal sheet used in the impact-absorbing structure 20 is particularly preferably a high-tensile steel sheet with a strength of 980 MPa or higher.

[0100] Furthermore, regarding the metal plates of the corrugated components 21 and 23 used in the impact-absorbing structure 20, their yield strength is preferably that of the floor beam 103 ( Figure 5 The yield strength of the metal plate is below that of the floor beam 103. This is because, in a side impact, the impact absorbing structure 20 reliably buckles and deforms before the floor beam 103, thus absorbing the impact energy sufficiently and suppressing the deformation of the floor beam 103.

[0101] When the yield strength of the metal plate constituting the impact-absorbing structure 20 is the same as that of the metal plate constituting the floor beam 103, it is preferable to provide reinforcing ribs (crushing ribs) or the like to the corrugated components constituting the impact-absorbing structure 20 so that buckling deformation can occur from the reinforcing ribs, thereby making the buckling strength (= the load at which the component itself begins to buckle) of the impact-absorbing structure 20 lower than that of the floor beam 103.

[0102] exist Figure 1 In the side beam structure 1 shown, regarding the impact-absorbing structure 20, the inner end 20a is joined (welded or bonded) to the bottom 31 of the recess 30 in the longitudinal face 11a of the side beam inner member 11, thereby being supported within the side beam 10. However, as Figure 7 As shown, the impact-absorbing structure 20 can also be supported within the side beam 10 via the support structure 37.

[0103] Figure 7 (a) shows a structure in which the upper end of the support structure 37 is joined to the lower surface of the impact absorption structure 20, and the lower end is joined to the flange portions 11c and 13c of the side beam 10. Figure 7 (b) shows a structure in which one end of the support structure 37 is joined to the lower surface of the impact-absorbing structure 20, and the other end is joined to the longitudinal face 13a of the side beam outer member 13. Figure 7 (c) shows a structure in which the impact-absorbing structure 20 is supported by support structures 37 disposed above and below the impact-absorbing structure 20. The manner in which the impact-absorbing structure 20 is supported by the support structures 37 is not limited to... Figure 7 (a) through (c) in the text. For example, it could also be in... Figure 7 The side beam structure 1 shown in (c) is a structure in which the impact absorbing structure 20 is supported only by a support structure 37 disposed above the impact absorbing structure 20.

[0104] In addition, the connection between the supporting structure 37 and the impact-absorbing structure 20 and the side beam 10 can be achieved by at least one of the following: spot welding, mechanical fastening with bolts, rivets, etc., or bonding.

[0105] In the above-described embodiment, the wave-shaped components 21 and 23 of the side beam structure 1 are arranged in a flipped configuration, and are otherwise identical to the wave shape in a cross-section orthogonal to the vehicle width direction. Furthermore, the convex shapes 21a and 23a and the concave shapes 21b and 23b of each wave-shaped component 21 and 23 preferably have the following characteristics: a height or depth of 15mm to 100mm; a width of 15mm to 150mm for the top surface of the convex shape 21a and the bottom surface of the concave shape 21b; and an inclination angle (the angle between the acute angle formed by the horizontal vertical line in the vertical direction of the vehicle and the wall) of each convex shape 21a and concave shape 21b, which is 1° to 30°. This allows the bottom surfaces of the concave shapes to be joined in a misaligned state, and the edges of the convex and concave shapes to be crushed during a side collision, thereby improving collision performance.

[0106] Furthermore, the convex and concave shapes of the wave-shaped components are not limited to being the same in a cross-section orthogonal to the vehicle width direction; they can also be different. For example, in order to facilitate the engagement of the bottom surfaces of the opposing concave shapes in a pair of wave-shaped components, the width of the bottom surface of the concave shape can be wider than the width of the top surface of the convex shape.

[0107] Example 1 Since an analysis was conducted to verify the effectiveness of the side beam structure of the automobile involved in this invention, it will be described below.

[0108] In Example 1, the purpose is to evaluate the collision characteristics of the side beam structure during a side impact of a vehicle, such as... Figure 8 As shown, a collision analysis was performed on a collision test in which the collider 210 collides with the side of the side beam 10 in the test body 200 which has the side beam structure 1.

[0109] Test specimen 200 simulates the aforementioned vehicle side structure 100. On the opposite side of the collision body 210 in the side beam 10, it has a floor beam simulation section 201 corresponding to the floor beam 103, a battery box wall section 203 corresponding to the side section 105a of the battery box 105, and a battery box bottom plate section (not shown) corresponding to the bottom plate 105b of the battery box 105. In test specimen 200, the battery box bottom plate section is fixed to the inner member 11 of the side beam by fixing bolts. Furthermore, the length of the floor beam simulation section 201 in the vehicle length direction is set to 160 mm.

[0110] In collision analysis, such as Figure 8 As shown, the impactor 210 collides with the test subject 200 in the vehicle width direction. Here, the impactor 210 is set as a rigid column with a radius of R127mm (equivalent to a diameter of 254mm), the initial velocity is set to 35.0km / h, and the maximum intrusion amount is set to 80mm. In addition, the load-bearing capacity (allowable load) of the floor beam simulation section 201 is set to 500kN or less, and the target value of the collision energy absorption of the side beam structure is set to 27kJ (equivalent to 90% of the collision energy generated by the impactor 210).

[0111] In collision analysis, such as Figure 8 As shown, the deformation behavior of the side beam 10 during the collision process of the colliding body 210, which collides with the side of the side beam 10, is determined. Then, based on the deformation behavior of the side beam 10, the relationship between the load input to the side beam 10 and the stroke, as well as the amount of collision energy absorbed from the start of the collision until the maximum intrusion is reached, are determined. The load input to the test body 200 is set as the load transferred to the rigid body clamp used to fix the test body 200.

[0112] Figure 9 The side beam structure used as the test object in the embodiment is shown in the figure. Figure 9 In the figures, (a) and (b) are the side beam structure 1 (Example 1 and Example 2) of the present invention, and (c) to (g) are the side beam structures 3 (Comparative Examples 1 to 3) used as comparative examples. Additionally, Figure 9 In the figures (a) to (g), the left figure is a cross-sectional view of the side beam 10 orthogonal to the vehicle length direction, and the right figure is a cross-sectional view of the impact absorbing structure 20 inside the side beam 10 orthogonal to the vehicle width direction.

[0113] Figure 9 In the side beam structure 1 of Invention Example 1 shown in (a), as the impact-absorbing structure 20 within the side beam 10, the concave shape 21b of the upper corrugated member 21 and the concave shape 23b of the lower corrugated member are arranged opposite each other, and their bottom surfaces are joined together in a state of misalignment in the vehicle length direction. Furthermore, in the side beam structure 1, the misalignment amount between the concave shape 21b and the concave shape 23b is set to W2 = 0.5 × W1 (the distance between the centers of the concave shape 21b and the concave shape 23b), and the recess amount D of the recess 30 provided in the inner member 11 of the side beam is set to 35 mm (1.0 times the height h of the impact-absorbing structure 20).

[0114] Figure 9 The side beam structure 1 shown in Example 2 of the invention (b) is made by changing the misalignment between the concave shape 21b and the concave shape 23b in Example 1 to W2 = 0.2 × W1.

[0115] Figure 9 The side beam structure 3 shown in Comparative Example 1 (c) includes a side beam 40 as an inner member 41, which has a longitudinal facet 41a that is flattened by removing the recess 30 of the inner member 11 in Example 1. Furthermore, the impact-absorbing structure 20, like in Example 1, has the misalignment W2 between the concave shapes 21b and 23b set to W2 = 0.5 × W1. It should be noted that, regarding the impact-absorbing structure 20, since the longitudinal facet 41a in the inner member 41 is flattened, its length in the vehicle width direction is shorter than that in Example 1.

[0116] Figure 9 The side beam structure 3 shown in Comparative Example 2 (d) is manufactured in the same manner as Comparative Example 1, having a longitudinal facet 41a that is flattened by removing the recess 30 of the side beam inner member 11 in Invention Example 2. Furthermore, the misalignment W2 between the concave shapes 21b and 23b in the impact-absorbing structure 20 is set to W2 = 0.0 × W1, that is, the bottom surfaces of the concave shapes 21b and 23b are joined together without misalignment in the vehicle length direction. Regarding the impact-absorbing structure 20, since the longitudinal facet 41a in the side beam inner member 41 is flattened, its length in the vehicle width direction is shorter than that of Invention Example 2.

[0117] Figure 9 Comparative Example 3 shown in (e) and Figure 9 The side beam structure 3 shown in Comparative Example 4 (f) has an impact-absorbing structure 50 installed inside the side beam 40, which is an impact-absorbing structure 20 from Comparative Example 2 with the lower corrugated member 23 removed. Furthermore, the thickness of the metal plate used as the raw material for the impact-absorbing structure 50 differs between Comparative Examples 3 and 4. Comparative Example 3, like Invention Examples 1 and 2 and Comparative Examples 1 and 2, has a thickness of 2.2 mm, while the thickness of the plate in Comparative Example 4 is thicker than that in Comparative Example 3, set at 3.2 mm.

[0118] Figure 9 The side beam structure 3 involved in Comparative Example 5 shown in (g) does not have an impact absorbing structure inside the side beam 40, and is only the side beam 40.

[0119] Table 1 summarizes the tensile strength and thickness of the metal plate used for the side beam 10 in Examples 1, 2 and Comparative Examples 1 to 5, the material (tensile strength), thickness, number of corrugated components constituting the impact absorption structures 20 and 50, the coefficient α of the misalignment amount W2 that imparts the concave shape, and the amount of recess D of the recess 30 provided in the longitudinal surface 11a of the inner member 11 of the side beam.

[0120] [Table 1] (Table 1) Figure 10 The image shows the deformation of the impact-absorbing structure 20 in a collision test of the test body 200 with side beam structure 1 according to Example 1 of the invention. Figure 10 (a) is a perspective view of the impact-absorbing structure 20 inside the side beam 10, viewed from above. Figure 10 (b) is a three-dimensional view of the impact-absorbing structure 20. Figure 10 (c) is a cross-sectional view of the vehicle in the vertical direction passing through the centerline of the collider 210.

[0121] In a collision test in which the collider 210 collides with the side of the test object 200, the collider 210 in Figure 10 The impact absorbing structure 20 is impacted at the point where the centerline of the collider 210 intersects with that of the impact absorbing structure 20, as shown in (a). Furthermore, as... Figure 10 As shown in (a), the centerline of the collider 210 intersects the lower wave-shaped component 23 on the top surface of the convex shape 23a, and the centerline of the collider 210 intersects the upper wave-shaped component 21 on the bottom surface of the concave shape 21b. The bottom surface of the concave shape 21b is sandwiched at the junction of the upper wave-shaped component 21 and the lower wave-shaped component 23. Figure 10 Between the ● mark (a) and the ridge line of the convex shape 21a. The bottom surface of the concave shape 23b in the lower corrugated member 23 has low deformation resistance, while the bottom surface of the concave shape 21b in the upper corrugated member 21 has relatively high deformation resistance. Therefore, in the impact absorbing structure 20, the out-of-plane deformation of the convex shape 23a of the lower corrugated member 23 is larger.

[0122] In addition, such as Figure 10 As shown in (c), in the impact-absorbing structure 20, the upper corrugated member 21 and the lower corrugated member 23 have different deformation resistances. As a result, the outer end 20b of the vehicle generates a rotational torque that rotates about the axis in the vehicle length direction in a downward direction, and the inner end 20a of the vehicle generates a rotational torque that rotates downward. Moreover, in each of the corrugated members 21 and 23 at the periphery of the impact position of the impactor 210, the inner and outer ends of the corrugated members undergo buckling deformation in the direction of rotation, which is similar to out-of-plane bending. As a result, the impact-absorbing structure 20 is tilted relative to the horizontal plane along the vehicle width direction.

[0123] Therefore, in the impact-absorbing structure 20, after the initial buckling deformation, no corrugated buckling deformation occurs; instead, the deformation continues to bend at the buckling deformation positions at both ends of the corrugated components 21 and 23. Thus, the side beam structure 1 according to Invention Example 1 can suppress load variations after the impact-absorbing structure 20 buckles during its collision, achieving... Figure 2The ideal load-stroke curve is shown.

[0124] Figure 11 The deformation behavior of the impact-absorbing structure 20 in a collision test of a test body 200 with a side beam structure 1 according to Example 1 of the invention is shown. Figure 11 This is a contour plot showing the distribution of equivalent plastic strain of the impact-absorbing structure from the start of the collision, where t is the elapsed time (s) from the start of the collision.

[0125] In the impact-absorbing structure 20, after the collision begins, the side of the impact body 210 that is impacted (the impact end side), namely the outer end 20b of the vehicle, and the R part (bent part) of the flange that is joined with the outer member of the side beam 13 are deformed (t ~ 0.002 sec).

[0126] Then, as deformation proceeds, the front end of the collision end deforms along the shape of the collision body 210, but at the end 20a on the opposite side of the collision end, i.e., on the side beam inner member 11 side, the strain expands in the vehicle length direction and deformation occurs in a range greater than the diameter of the collision body (t ~ 0.006 sec).

[0127] Then, the transverse facet 11b of the side beam inner member 11 and the convex ridge in the impact-absorbing structure 20 buckle, the strain is concentrated at the buckling location, and the new buckling location propagates in the vehicle length direction.

[0128] Table 1 above shows a comparison of the collision energy absorption at the maximum intrusion of the collider 210 in Invention Examples 1 and 2 and Comparative Examples 1 to 5. Regarding the maximum intrusion of the collider 210, it is 79.9 mm in Invention Example 1, and 80 mm in Invention Example 2 and Comparative Examples 1 to 5.

[0129] In Invention Examples 1 and 2, the maximum loads (maximum values ​​of contact reaction forces) are 465 kN and 469 kN, respectively, both lower than the allowable load of the floor beam, which is a load-bearing component, i.e., 500 kN. Furthermore, the collision energy absorption amounts are 30.0 kN and 27.9 kN, respectively, exceeding the target collision energy absorption amount (=27.0 kN).

[0130] In contrast, in Comparative Example 1, where the recess 30 was removed from the side beam structure 1 of Invention Example 1, during the crushing of the side beam structure 3, the inner end 20a of the impact-absorbing structure 20 was significantly misaligned above the vehicle, and the crushing of the impact-absorbing structure 20 did not progress sufficiently. As a result, the maximum load was 403 kN, lower than the maximum load of Invention Example 1 (=465 kN). Furthermore, the collision absorption energy at the maximum stroke of 80 mm was 403 kN, a 13% reduction compared to the collision absorption energy of Invention Example 1 (=465 kJ).

[0131] In Comparative Example 2, where the concave shape 21b of the upper corrugated member 21 and the concave shape 23b of the lower corrugated member 23 are joined together without misalignment in the vehicle length direction, the positions of the ridges of the upper and lower corrugated members 21 and 23 in the vehicle length direction are concentrated. Therefore, in Comparative Example 2, compared with Comparative Example 1, the maximum load increases to 514 kN, exceeding the load-bearing capacity of the floor beam (=500 kN). Furthermore, since the maximum load increases compared with Comparative Example 1, the collision energy absorption is 25.8 kJ. Although this is an increase compared with Comparative Example 1, the target collision energy (27.0 kJ) is not achieved.

[0132] In Comparative Example 3, which is equipped with an impact-absorbing structure 50 (with the lower corrugated component removed from the impact-absorbing structure 20 in Comparative Example 2), the maximum load is 348 kN, which is significantly lower than that in Invention Examples 1 and 2. Furthermore, with the reduction in maximum load, the amount of impact energy absorbed also decreases to 17.4 kJ, which is significantly lower than the target amount of impact energy absorption.

[0133] Comparative Example 4 achieved the target impact energy absorption of 29.3 kJ by increasing the thickness of the impact-absorbing structure 50 in Comparative Example 3 (2.2 → 3.2 mm). However, the maximum load was 526 kN, significantly exceeding the floor beam's load-bearing capacity of 500 kN.

[0134] The results of Comparative Example 5 show the collision characteristics of the side beam 40 itself, with the collision energy absorption limited to 1.3 kJ.

[0135] Figure 12 The diagram illustrates the relationship between the collision energy absorbed by the side beam structure and the maximum load input to the side beam structure during the side impact test in Example 1. Figure 12 As shown, in Invention Examples 1 and 2, the amount of collision energy absorbed is higher than that in Comparative Examples 1 to 5. Furthermore, the maximum load during a side collision can be suppressed to a level lower than the allowable load of the load-bearing component.

[0136] Example 2 In Example 2, in the impact absorption structure installed in the side beam, the misalignment between the concave shape of the upper wave-shaped component and the concave shape of the lower wave-shaped component is different, thereby verifying the influence on the amount of impact energy absorbed during a side collision.

[0137] In Example 2, similar to Example 1 described above, the collider 210 was subjected to a collision... Figure 8 The collision analysis of the side beam 10 in the test body 200 with the side beam structure 1 shown is performed during a collision test. Similar to Embodiment 1 described above, in the collision analysis, as... Figure 8 As shown, the impactor 210 collides with the test subject 200 in a direction orthogonal to the vehicle's length direction with an initial velocity of 35.0 km / h and a maximum intrusion of 80 mm. The impactor 210 is a rigid column with a radius of R127 mm (equivalent to a diameter of 254 mm). In addition, the load-bearing capacity of the floor beam simulation section 201 is set to be less than 500 kN, and the target value for the impact energy absorption of the side beam structure 1 is set to 27 kJ (equivalent to 90% of the impact energy generated by the impactor 210).

[0138] In Example 2, Figure 13 The impact-absorbing structure 20 shown in (a) is disposed in the test body 200 within the side beam 10 as Example 3 of the invention. In the impact-absorbing structure 20 of Example 3 of the invention, the misalignment W2 between the concave shape 21b of the upper wave-shaped member 21 and the concave shape 23b of the lower wave-shaped member 23 is set to 50% (50% misalignment) of the center-to-center distance W1 between the adjacent convex shape 21a and the concave shape 21b.

[0139] In addition, in Example 2, as a comparison object, Figure 13 As shown in (b), the impact-absorbing structure 20 is installed on the test specimen 200 of the side beam 10 as Comparative Example 6. Figure 13 The impact-absorbing structure 50 shown in (c) is installed in the side beam as a test specimen as comparative example 7.

[0140] In the impact-absorbing structures 20 of Comparative Examples 6 and 7, the bottom surfaces are joined together without misalignment (0% misalignment) between the centers of the concave shape 21b of the upper wave-shaped member 21 and the concave shape 23b of the lower wave-shaped member 23 in the vehicle length direction. Furthermore, the impact-absorbing structure 50 of Comparative Example 8 removes the lower wave-shaped member 23 from the impact-absorbing structure 20 of Comparative Example 2, and is composed only of the upper wave-shaped member 21 (one wave-shaped member).

[0141] In Invention Example 3, Comparative Example 7, and Comparative Example 8, metal plates with the thickness and tensile strength shown in Table 1 above were used to ensure that the maximum load during a side impact was an allowable load of 500 kN or less. In Comparative Example 6, the misalignment W2 in Invention Example 3 was changed from 50% to 0%, and a metal plate with the same thickness and tensile strength as in Invention Example 3 was used.

[0142] Figure 14 The image shows a cross-sectional view of the side beam structure 1, illustrating the deformation process of the impact-absorbing structure 20 disposed within the side beam 10. Figure 14 (a) is a cross-sectional view of the side beam structure involved in Example 3 of the invention. Figure 14 (b) is a cross-sectional view of the side beam structure 1 involved in Comparative Example 6. In Invention Example 3, the concave shape of the upper corrugated member in the impact-absorbing structure is opposite to the concave shape of the lower corrugated member, and they are asymmetrically aligned and joined in a misaligned state in the vehicle length direction. As a result, a rotational torque is generated that rotates about the axis in the vehicle length direction, and the ends on the inner and outer sides of the vehicle undergo buckling deformation such as out-of-plane bending in the direction of rotation.

[0143] On the other hand, in Comparative Example 6, after the initial buckling deformation occurs at the end of the outer side of the vehicle, corrugated buckling deformation is continuously generated from the outer side of the vehicle toward the inner side of the vehicle while undulating in a manner with multiple antinodes.

[0144] Figure 15 The diagram shows the load-stroke curves obtained through collision analysis of the test specimen 200 involved in the side impact test of Example 3 and Comparative Example 6. In Example 3, the load variation after the initial buckling deformation is suppressed, maintaining a constant load below the withstand load (allowable load = 500 kN). In contrast, in Comparative Example 6, after the initial buckling deformation, the load continues to increase, reaching a maximum load exceeding the withstand load (= 624 kN > 500 kN).

[0145] Figure 16 Table 2 shows (a) the load-stroke curves and (b) the shift in collision energy absorption obtained through collision analysis for the test body 200 involved in side impact tests of Invention Example 3, Comparative Example 7, and Comparative Example 8. Additionally, Table 2 summarizes the collision energy absorption, maximum load, and maximum intrusion of the colliding body at a stroke of 80 mm for each of Invention Example 3, Comparative Example 7, and Comparative Example 8, obtained through collision analysis.

[0146] [Table 2] In Invention Example 3, such as Figure 16 As shown in (a) of the diagram, the load rises rapidly (rigidity) in the initial stage of the collision, and the load variation after buckling is suppressed, maintaining a constant load. Moreover, as Figure 16 As shown in (b), the target collision absorption energy of 30kJ is achieved when the stroke is 80mm.

[0147] In contrast, in Comparative Example 7, such as Figure 16 As shown in (a), the load increases slowly (rigidity) in the initial stage of the collision, and the load continues to increase even after buckling occurs. Furthermore, the maximum load at a stroke of less than 80 mm is 475 kN, which is lower than the value in Example 6 of the Invention. Therefore, as... Figure 16 As shown in (b), the amount of collision energy absorbed during the collision process shifts to a value lower than that of Invention Example 3, with a collision energy of 26.7 kJ at a stroke of 80 mm. Moreover, the maximum intrusion of the collider required to achieve the target collision energy absorption of 30 kJ is 87.3 mm, which is an increase compared to Invention Example 3.

[0148] In comparison example 8, such as Figure 16 As shown in (a), the load increase (rigidity) in the initial stage of the collision was slower than in Comparative Example 7, and the load continued to increase even after buckling occurred. Furthermore, although the maximum load of 479 kN at a stroke of 80 mm or less was similar to that of Comparative Example 7, the amount of collision energy absorbed during the collision process was lower than that of Comparative Example 6, with a collision energy of 24.2 kJ at a stroke of 80 mm. Moreover, the maximum intrusion of the collider required to achieve the target collision energy absorption of 30 kJ was 93.2 mm, which was greater than that of Comparative Example 7.

[0149] Industrial availability According to the present invention, a side beam structure for a car is provided that improves the collision performance during side impacts without increasing weight and manufacturing costs.

[0150] Explanation of reference numerals in the attached figures 1. Side beam structure (invention example) 3. Side beam structure (comparative example) 10 Side beams 11. Internal components of the side beam 11a Longitudinal face 11b Horizontal face 11c Flange portion 13 Side beam external components 13a Longitudinal face 13b Horizontal face 13c Flange 20 Impact Absorbing Structures 20a The end of the inner side of the vehicle 20b The outer end of the vehicle 21. Upper wave-shaped component 21a Convex shape 21b Concave shape 23. The lower wave-shaped component 23a Convex shape 23b Concave shape 25 Flange portion 30 concavity 31 Bottom 33 Wall section 35 L-shaped bracket 37 Supporting structures 40 Side beam 41. Internal components of the side beam 41a Longitudinal face 50 Impact Absorbing Structure 100 Vehicle side structure 101 base plate 101a Flange 103 Floor Beams 103a End of vehicle in width direction 105 Battery Box 105a Side profile 105b base plate 105c Mounting Flange 107 Battery Pack 109 Fixing Bolts 200 test subjects 201 Floor Beam Simulation Department 203 Battery box wall 210 Collider

Claims

1. A side beam structure for an automobile, comprising a side beam having an inner side beam member and an outer side beam member, wherein the inner side beam member extends along the length direction of the vehicle and has a groove shape with an opening to the outer side of the vehicle in the width direction, and the outer side beam member extends along the length direction of the vehicle and has a groove shape with an opening to the inner side of the vehicle in the width direction, wherein the inner side beam member and the outer side beam member are joined such that their opening sides face each other. The side beam structure of the automobile has: An impact-absorbing structure is disposed within the side beam, with its inner end in the vehicle width direction connected to the bottom of the groove shape of the inner member of the side beam, and / or its outer end in the vehicle width direction connected to the bottom of the groove shape of the outer member of the side beam. The impact-absorbing structure absorbs the impact input to the side beam during a side collision of the vehicle. The upper and lower restraint structure, located at the bottom of the inner member of the side beam, restrains the inner end of the vehicle in the vertical direction during a side collision. The shock-absorbing structure has a pair of wave-shaped components. The pair of wave-shaped components have alternating and continuous convex and concave shapes in a cross-section orthogonal to the vehicle width direction in the vehicle length direction, and are disposed in the vertical direction of the vehicle. The pair of wave-shaped components are made of metal plates, with the concave shape of the upper wave-shaped component and the concave shape of the lower wave-shaped component being arranged opposite each other, and the pair of wave-shaped components are joined in a state where the opposite concave shapes are misaligned in the vehicle length direction.

2. The side beam structure of the automobile as described in claim 1, wherein, The upper and lower constraint structure is a recessed portion with the bottom of the groove shape in the inner component of the side beam, which is recessed towards the vehicle width direction. The end of the impact absorbing structure on the inner side of the vehicle is inserted into the recessed portion.

3. The side beam structure of the automobile as described in claim 1 or 2, wherein, The front end of the impact-absorbing structure on the outer side of the vehicle in the vehicle width direction contacts the bottom of the groove shape in the outer member of the side beam in such a way that it abuts against it.

4. The side beam structure of the automobile as described in any one of claims 1 to 3, wherein, The misalignment W2 of the opposite concave shapes in the upper and lower wave-shaped components in the vehicle length direction is more than 20% and less than 50% of the center distance W1 between the adjacent convex and concave shapes in the wave-shaped components in the vehicle length direction.

5. The side beam structure of the automobile as described in claim 2, wherein, The recess D of the recess provided in the inner part of the side beam is more than 0.8 times and less than 1.2 times the vertical height h of the impact absorbing structure in the vehicle direction.

6. The side beam structure of the automobile as described in any one of claims 1 to 5, wherein, The wave-shaped component is a metal plate component with a tensile strength of 590 MPa or higher.

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