Vehicle body frame structure

Abstract

The vehicle body frame structure according to the present application is capable of improving the collision safety of a vehicle body, and is capable of reducing the weight of the vehicle body, unlike conventional vehicle body frame structures, and is capable of easily manufacturing the frame members. Furthermore, the vehicle body frame structure according to the present application is capable of contributing to the development of sustainable transportation systems. The vehicle body frame structure according to the present application includes a frame member (lower side rail outer member (12)) having a hat-shaped cross section, and is characterized in that a concave-convex shaped portion (3) having a convex portion (31) toward the outside of the hat shape and a concave portion (32) toward the inside alternately and continuously formed in a wavy shape is formed in a side surface (Sb2) of the hat shape among a top surface (Sa2) and the side surface (Sb2), and the height (H1) from the side surface (Sb2) is equal to or less than the thickness (T1) of the frame member (lower side rail outer member (12)).

Description

Technical Field

[0001] This invention relates to vehicle chassis structure. Background Technology

[0002] In recent years, initiatives to provide pathways to a sustainable transportation system that also considers vulnerable populations such as the elderly and children have become increasingly active. Efforts are underway to further improve transportation safety and convenience by developing advancements in vehicle collision safety performance to achieve this goal.

[0003] Conventionally, chassis frame structures with frame components made of high-strength steel plates that, when viewed in cross-section, are known to be hat-shaped (see, for example, Patent Document 1). Specifically, the frame component has a flange corresponding to the hat-shaped flange portion and a body corresponding to the crown portion (bulge), and has a pair of reinforcing ribs extending from the top surface, respectively along a pair of ridges formed between the top surface and the side surface in the crown portion. These reinforcing ribs are formed by recessing a portion of the top surface into a groove shape towards the inside of the crown portion.

[0004] According to this frame component, if a collision load is applied to the top surface causing the crown section to compress and deform, the stiffeners deform by widening their amplitude through a tensile force acting on the top surface between a pair of ridges. This frame component absorbs the collision load and suppresses frame component fracture by deforming in a way that widens the amplitude of the stiffeners. Therefore, the frame structure contributes to improved collision safety performance.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2014-101094 Summary of the Invention

[0008] However, conventional chassis frame structures (such as those described in Patent Document 1) require sufficient depth of reinforcing ribs to adequately alleviate tensile forces acting on the top surface. However, if the depth of the reinforcing ribs increases, the chassis component suffers from an increased perimeter and weight in its cross-sectional shape. Furthermore, the chassis component, constructed from high-strength steel plates, lacks material ductility, making it difficult to achieve sufficiently deep reinforcing ribs on the top surface.

[0009] Therefore, the objective of this invention is to provide a vehicle frame structure that improves the collision safety performance of the vehicle body, achieves weight reduction unlike previous methods, and facilitates the manufacture of frame components. Furthermore, this contributes to the development of sustainable transportation systems.

[0010] The present invention, which solves the above-mentioned problems, has a frame component formed with a cross-section in the shape of a hat. The frame component is characterized in that the top surface and the side surface constituting the hat shape have a wave-like convex-concave shape portion formed by alternating and continuous protrusions facing outwards and concave portions facing inwards. The convex-concave shape portion is formed such that its height from the side surface is less than or equal to the plate thickness of the frame component.

[0011] Invention Effects

[0012] According to the present invention, a vehicle frame structure can be provided that improves the collision safety performance of the vehicle body, achieves weight reduction unlike previous methods, and facilitates the manufacture of frame components. Furthermore, this contributes to the development of sustainable transportation systems. Attached Figure Description

[0013] Figure 1 This is a side view of the left side portion of a vehicle body having the chassis frame structure according to an embodiment of the present invention.

[0014] Figure 2 This is a partial perspective view of the chassis component in the chassis structure according to an embodiment of the present invention.

[0015] Figure 3 yes Figure 2 Section III-III.

[0016] Figure 4 yes Figure 3 A magnified view of part IV.

[0017] Figure 5 yes Figure 4 A magnified view of the V-shaped part.

[0018] Figure 6 This is a partial cross-sectional view of a frame component that schematically illustrates the deformation of a frame component constituting the vehicle frame structure of an embodiment of the present invention under a collision load.

[0019] Figure 7A This is a CAE (Computer Aided Engineering) analysis diagram of the stress distribution and deformation range of the frame component during a spherical side impact according to an embodiment of the present invention.

[0020] Figure 7B This is a CAE analysis diagram of the stress distribution and deformation range during a spherical side impact of a frame component of a comparative example of the present invention.

[0021] Figure 8 This is a load-travel diagram of the frame components that constitute the vehicle frame structure of the embodiment of the present invention.

[0022] Figure 9 This is a partial sectional view of a modified frame component.

[0023] Explanation of reference numerals in the attached figures

[0024] 1. Lower longitudinal beam (chassis component)

[0025] 2 front pillars

[0026] 3. Concave and convex shapes

[0027] 6 Rear wheel covers

[0028] 12. Lower longitudinal beam outer components (outer parts of the lower longitudinal beam)

[0029] 12a edge

[0030] 12b Flat section

[0031] 31 convex part

[0032] 32 recess

[0033] The joint between the outer component of the C1 lower longitudinal beam and the front column

[0034] The joint between the outer component of the C2 lower longitudinal beam and the rear wheel arch

[0035] The height of the H1 concave-convex shape (convex part) from the side surface

[0036] S-shaped chassis structure

[0037] Top surface of the outer member of the lower longitudinal beam of Sa2

[0038] The side of the outer member of the lower longitudinal beam of Sb2

[0039] The center of the side of the outer member of the lower longitudinal beam of Sbc

[0040] Thickness of T1 lower longitudinal beam (outer component of lower longitudinal beam) Detailed Implementation

[0041] Next, refer to the appendix as appropriate. Figure 1 The following describes in detail the vehicle frame structure used to implement the present invention (implementation method). Furthermore, the arrows in the accompanying drawings indicate the same directions as the vehicle body's front-rear, rear-down, left-right, and right-right directions. Additionally, in the following description, the left-right direction of the vehicle body is sometimes referred to as the vehicle width direction.

[0042] The chassis frame structure of this embodiment is a chassis component with a hat-shaped cross-section. Its main feature is that the side of the hat-shaped structure has a small wave shape (concave-convex shape) with a wave height less than the thickness of the chassis component.

[0043] The following description of the chassis frame structure will be based on the outer component of the lower longitudinal beam, which is a component of the chassis frame, namely the lower longitudinal beam outer member (lower longitudinal beam outer member). However, the chassis frame components are not limited to this and can be applied to various chassis components in the vehicle body.

[0044] In this embodiment, the chassis frame structure corresponds to the lower longitudinal beams located on the left and right sides of the chassis and is arranged on the left and right sides of the chassis, but they have a symmetrical structure. Therefore, only the chassis frame structure on the left side of this embodiment will be described, and a detailed description of the chassis frame structure on the right side will be omitted.

[0045] The overall structure of the vehicle body with this chassis frame structure will be described below, followed by a detailed explanation of the chassis frame structure.

[0046] Overall Structure of the Vehicle Body

[0047] Figure 1 This is a side view of the left side portion of the vehicle body 10 having the vehicle frame structure S of this embodiment.

[0048] like Figure 1 As shown, the body 10 mainly consists of a lower longitudinal beam 1, a front pillar 2, a middle pillar 4, a rear wheel arch 6, a side pillar 7, and a roof side beam 8.

[0049] Although the lower longitudinal beam 1 will be described in detail later, it is a long component that extends along the front-rear direction of the vehicle body on the outer side of the vehicle width at the lower part of the vehicle body.

[0050] The lower end of the front column 2 is connected to the front end of the lower longitudinal beam 1. The front column 2 extends upward from the joint C1 formed by the overlap of the front end of the lower longitudinal beam 1 and the lower end of the front column 2.

[0051] Furthermore, the upper end of the front pillar 2, which extends backward at an angle midway upward, is connected to the front end of the roof side beam 8.

[0052] also, Figure 1 In the attached drawing, reference numeral 2a refers to the secondary front pillar that forms a generally triangular shape between itself and the leading edge of the front pillar 2, forming the secondary window 2b. This secondary front pillar 2a is inclined such that it extends downwards as it extends forward from the upper end of the front pillar 2. Specifically, the front portion of the secondary front pillar 2a extends toward the rear end of a body component (not shown).

[0053] In addition, a central pillar 4 extends upward from the center of the lower longitudinal beam 1 in the front-rear direction of the vehicle body.

[0054] The rear end of the lower longitudinal beam 1 is connected to the front end of the rear wheel cover 6.

[0055] The rear wheel arch 6 has a wheel arch 6a extending rearward in an arc shape from the joint C2 formed by overlapping with the lower longitudinal beam 1, and an outer half of the shock absorber housing 6b integrally formed with the upper part of the wheel arch 6a.

[0056] Furthermore, the rear wheel cover 6 in this embodiment is conceived to be formed such that a portion of the rear side panel 5 partially bulges outward in the vehicle width direction.

[0057] Additionally, a side beam 7 is connected to the upper front side of the rear wheel arch 6. The side beam 7 is integrally formed with the rear wheel arch 6 and extends upward from the rear wheel arch 6 at a slightly forward angle.

[0058] Furthermore, the upper ends of the front pillar 2, the middle pillar 4, and the side pillar 7 are connected to the roof side beam 8, which extends along the front-rear direction of the vehicle body on the outer side of the vehicle width direction on the upper part of the vehicle body.

[0059] Chassis Structure

[0060] Next, the chassis frame structure S of this embodiment will be described (refer to...). Figure 1 ).

[0061] The chassis frame structure S of this embodiment is configured to have a lower longitudinal beam 1 as a chassis component.

[0062] Figure 2 This is a partial 3D view of the lower longitudinal beam 1. Figure 3 yes Figure 2 Section III-III.

[0063] like Figure 2 As shown, the lower longitudinal beam 1 has an inner member 11 and an outer member 12.

[0064] Furthermore, the lower longitudinal beam outer member 12 corresponds to the "lower longitudinal beam outer component" as referred to in the technical solution. Additionally, Figure 2 as well as Figure 3 In the middle, for ease of drawing, the lower longitudinal beam internal component 11 is represented by an imaginary line (double-dotted line).

[0065] like Figure 2 As shown, the lower longitudinal beam 1 in this embodiment is a frame component with a closed cross-section structure, which is positioned inside the vehicle width direction (…). Figure 2 The inner member 11 of the lower longitudinal beam with a hat-shaped cross-section on the right side and positioned on the outer side in the vehicle width direction ( Figure 2 The outer component 12 of the lower longitudinal beam (outer part of the lower longitudinal beam) with a hat-shaped cross section on the right side is a closed cross section structure formed by welding.

[0066] Figure 2 In the figure, reference numeral 3 refers to the concave-convex shape formed on the outer member 12 of the lower longitudinal beam, which will be described in detail later.

[0067] like Figure 3 As shown, in the lower longitudinal beam inner member 11 and the lower longitudinal beam outer member 12, the flanges Fa, Fa and Fb, Fb corresponding to the hat-shaped flange portions are joined together by welding. Furthermore, the hollow portion 1a (closed section) of the lower longitudinal beam 1 is formed by the top surface Sa1 and a pair of side surfaces Sb1, Sb1 of the hat-shaped crown portion (bulge portion) in the lower longitudinal beam inner member 11, and the top surface Sa2 and a pair of side surfaces Sb2, Sb2 of the hat-shaped crown portion in the lower longitudinal beam outer member 12.

[0068] On a pair of side surfaces Sb2, Sb2 of the lower longitudinal beam outer member 12 (lower longitudinal beam outer component) in this embodiment, wavy concave-convex shaped portions 3 are formed respectively.

[0069] Furthermore, the concave-convex shape portions 3 formed on the sides Sb2 and Sb2 are formed symmetrically above and below each other. Therefore, in the following description, only the concave-convex shape portions 3 formed on the upper side Sb2 will be described, and the description of the concave-convex shape portions 3 formed on the lower side Sb2 will be omitted.

[0070] Figure 4 yes Figure 3 A magnified view of part IV. Figure 5 yes Figure 4 A magnified view of the V-shaped part.

[0071] like Figure 4 As shown, the concave-convex shaped part 3 is composed of a protrusion 31 and a concave part 32. The protrusion 31 faces outward of the hat shape, that is, towards the lower longitudinal beam 1 formed by the lower longitudinal beam outer member 12 (see reference). Figure 3 The hollow portion 1a protrudes to the opposite side of the hollow portion 1a, and the recess 32 faces the hollow portion 1a side, i.e., the inner side.

[0072] Furthermore, a recess 31a is formed on the inner side of the protrusion 31 that protrudes outward in a manner corresponding to the protrusion 31, and a protrusion 32a is formed on the inner side of the recess 32 that protrudes inward in a manner corresponding to the recess 32.

[0073] That is, the concave-convex shape 3 formed on the side surface Sb2 constitutes a corrugated plate with convex part 31 and concave part 32 alternating continuously in the direction away from the top surface Sa2 side of the hat shape.

[0074] Furthermore, the protrusion 31 is formed along the long side direction of the lower longitudinal beam outer member 12 (and...). Figure 4 The mountain-shaped part (extending vertically to the paper surface) is a reinforcing rib, and the concave part 32 forms a trough-shaped valley that extends along the long side of the lower longitudinal beam outer member 12.

[0075] like Figure 2As shown, such a concave-convex shape 3 extends parallel to the ridge 12a that extends along the long side direction of the lower longitudinal beam outer member 12 between the top surface Sa2 and the side surface Sb2.

[0076] Furthermore, the concave-convex shape portion 3 is formed in a ratio of Figure 1 The portion A shown is located rearward of the joint C1 between the lower longitudinal beam 1 (lower longitudinal beam outer member 12) and the front pillar 2, and forward of the joint C2 between the lower longitudinal beam 1 (lower longitudinal beam outer member 12) and the rear wheel arch 6. In other words, the concave-convex shape portion 3 (see reference...) Figure 4 Formed in component 12 (refer to) excluding the lower longitudinal beam Figure 1 ) and the front pillar 2 (refer to Figure 1 The front end of the overlapping lower longitudinal beam outer member 12 and the lower longitudinal beam outer member 12 and the rear wheel arch 6 (see reference) Figure 1 The area A outside the rear end of the overlapping lower longitudinal beam outer member 12 (refer to) Figure 1 Furthermore, as long as the concave-convex shape portion 3 is located within range A other than the rear end of the lower longitudinal beam outer member 12, it can also be partially formed in the length direction of the lower longitudinal beam outer member 12.

[0077] In addition, such as Figure 4 As shown, in this embodiment, the concave-convex shape portion 3 is formed by displacement towards the top surface Sa2 compared to the center Sbc of the side surface Sb2.

[0078] In addition, such as Figure 5 As shown, in this embodiment, the ridge portion 12a is formed by an arc-shaped curved surface between the top surface Sa2 and the side surface Sb2. Furthermore, the concave-convex shape portion 3 is arranged adjacent to the ridge portion 12a.

[0079] Specifically, the concave-convex shape portion 3 is connected to the ridge portion 12a via the flat portion 12b and disposed on the side surface Sb2. Incidentally, the flat portion 12b is formed with the same plate thickness as the ordinary portion of the side surface Sb2 where the concave-convex shape portion 3 is not formed, and extends along the extension line of the ordinary portion. There is no particular limitation on the length of such flat portion 12b, but it is desirable to set it to be shorter than the width W1 of the protrusion 31.

[0080] By providing such a flat portion 12b, the deformation of the side surface Sb2, which is based on the concave-convex shape portion 3, will be more effectively promoted (see reference). Figure 6 ).

[0081] Furthermore, the concave-convex shape portion 3 can also be configured to connect directly to the edge portion 12a without passing through the flat portion 12b.

[0082] The height H1 of the concave-convex shape portion 3 from the side surface Sb2 is formed such that it is less than or equal to the plate thickness T1 of the lower longitudinal beam outer member 12.

[0083] Specifically, such as Figure 5 As shown, the height H1 of the protrusion 31 in the concave-convex shape 3 from the side surface Sb2 is formed such that it is less than or equal to the plate thickness T1 of the lower longitudinal beam outer member 12.

[0084] Additionally, as explained later, the height H2 of the protrusion 32a protruding from the inner side of the recess 32 from the side surface Sb2 (refer to...) Figure 9 It is also hoped that it will be formed in a manner that is less than or equal to the plate thickness T1 of the lower longitudinal beam outer member 12.

[0085] The lower longitudinal beam outer member 12 (lower longitudinal beam outer part) of this embodiment, which has the above-described concave-convex shape 3, is envisioned as a stamped product of high-tensile steel sheet.

[0086] Such a lower longitudinal beam outer member 12 can be obtained by a manufacturing method that uses a mold with a cavity to stamp a high-tensile steel plate of a specified thickness, the cavity mimicking the shape of a concave-convex shape portion 3, for example, which has rebound prediction compensation performed, at a specified position.

[0087] Alternatively, the lower longitudinal beam outer member 12 can also be obtained by a manufacturing method in which a primary stamping form is prepared in which the height of the concave-convex shape portion 3 from the side surface Sb2 exceeds the plate thickness of the lower longitudinal beam outer member 12, and a secondary stamping forming process is performed on the primary stamping form by in-plane compression in the final die, thereby reducing the height of the concave-convex shape portion 3. The concave-convex shape portion 3 of the lower longitudinal beam outer member 12 obtained by this manufacturing method is composed of a wave-shaped portion (rebound forming portion) formed by rebound.

[0088] Effects and Functions

[0089] The following explains the effects of the vehicle frame structure S in this embodiment. First, the basic effects of the vehicle frame structure S, generated by the deformation of the lower longitudinal beam outer member 12 during a side collision of the vehicle body 10, will be explained.

[0090] Figure 6 This is a partial cross-sectional view schematically showing the deformation of the lower longitudinal beam outer member 12, which is a component of the vehicle frame, under a collision load. Furthermore, for ease of drawing, the details are exaggerated. Figure 6 The shape, size, and plate thickness of the concave-convex shape part 3, the convex part 31, and the concave part 32 in the figure are different from those in reality.

[0091] Figure 6 In this embodiment, the lower longitudinal beam outer component 12 is depicted with solid lines as an example.

[0092] in addition, Figure 6In the comparative example, the lower longitudinal beam outer member 13, depicted by dotted lines, has the same configuration as the lower longitudinal beam outer member 12 in the embodiment, except that it does not have the concave-convex shape portion 3.

[0093] like Figure 6 As shown in (i), before the collision load is applied to the top surface Sa2, the embodiment and the comparative example have the same shape that overlaps when viewed in cross section, except for the concave-convex shape 3.

[0094] Next, as Figure 6 As shown in (ii), in the early stage of applying a collision load Ld to the top surface Sa2, the embodiment and the comparative example cause the central portion of the top surface Sa2 to extend inward in the vehicle width direction to the same extent. Figure 6 The right side of the sample is deformed in a recessed manner. Furthermore, in the early stage, the side surface Sb2 of the embodiment with the concave-convex shape 3 begins to bulge outward from the hollow portion 1a compared to the side surface Sb2 of the comparative example.

[0095] Next, as Figure 6 As shown in (iii), in the intermediate stage when a collision load Ld is applied to the top surface Sa2, in the comparative example, the side surface Sb2 wants to tilt toward the flange Fb side. However, the tilting of the side surface Sb2 toward the flange Fb side is suppressed by the tensile force acting in the front-rear direction in the top surface Sa2.

[0096] In contrast, in this embodiment, starting from the wave shape of the concave-convex shape portion 3, the side Sb2 bulges further outward towards the outer side of the hat shape compared to the previous stage and tilts towards the flange Fb side.

[0097] Next, as Figure 6 As shown in (iv), in the comparative example, even in the later stage when a collision load Ld is applied to the top surface Sa2, the tilting action of the side surface Sb2 is slow.

[0098] In contrast, in this embodiment, the corrugated plate portion forming the concave-convex shape 3 extends in a flat plate shape, thereby further promoting the tilting of the side surface Sb2 toward the flange Fb side.

[0099] Compared with the comparative example, the displacement of the top surface Sa2 in the vehicle width direction (outside the hollow part 1a) is increased in this embodiment, and the front and rear deformation of the hat shape is increased by making the side surface Sb2 tilt more.

[0100] According to such an embodiment of the present invention, compared with the comparative example, the displacement of the top surface Sa2 and the deformation range of the hat shape are increased, and the absorption performance of the side impact load is excellent.

[0101] Figure 7AThis is a CAE (Computer Aided Engineering) analysis diagram of the stress distribution and deformation range of the lower longitudinal beam outer member 12 during a spherical side collision in the above embodiment. Figure 7B This is a CAE analysis diagram of the stress distribution and deformation range of the lower longitudinal beam outer member 13 in the comparative example above during a spherical side collision.

[0102] Figure 7A as well as Figure 7B The lower longitudinal beam outer components 12 and 13 are represented by their appearance when viewed from above. Figure 7A as well as Figure 7B In the figures, P is a sphere. The stress distribution of the lower longitudinal beam outer member 12 in the embodiment and the lower longitudinal beam outer member 13 in the comparative example is indicated by a darker shading as the stress increases.

[0103] like Figure 7A as well as Figure 7B As shown, the deformation range in the front-rear direction of each of the lower longitudinal beam outer members 12 and 13 during a spherical side collision was verified. Compared with the lower longitudinal beam outer member 13 (comparative example), the lower longitudinal beam outer member 12 (embodiment) is larger.

[0104] In addition, it was verified that the stress of the lower longitudinal beam outer member 12 (example) is more dispersed compared with the lower longitudinal beam outer member 13 (comparative example).

[0105] This verifies that, according to this embodiment of the invention, the breakage of the lower longitudinal beam outer member 12 during a spherical side impact can be prevented more reliably than in the comparative example.

[0106] Figure 8 This is a load-travel diagram of the lower longitudinal beam outer member 12 of the embodiment and the lower longitudinal beam outer member 13 of the comparative example. This load-travel diagram shows the load-travel distance from the top surface Sa2 (reference) for the lower longitudinal beam outer member 12 (embodiment) and the lower longitudinal beam outer member 13 (comparative example), which are supported at both ends. Figure 6 Apply load Ld to the side (refer to) Figure 6 The result when ).

[0107] like Figure 8 As shown, it is verified that the bending strength of the lower longitudinal beam outer member 12 of the embodiment is further improved compared with the lower longitudinal beam outer member 13 of the comparative example.

[0108] Next, the specific effects of the vehicle frame structure S in this embodiment will be explained.

[0109] In this embodiment, the vehicle frame structure S has a wave-shaped convex-concave portion 3 on the side surface Sb2 of the lower longitudinal beam outer member 12 with a hat-shaped cross section. In addition, the protrusion 31 in the convex-concave portion 3 is formed such that the height H1 from the side surface Sb2 (hereinafter referred to as "the height of the convex-concave portion 3") is less than or equal to the plate thickness T1 of the lower longitudinal beam outer member 12 (vehicle frame component).

[0110] According to this chassis frame structure S, when a side impact load is applied to the top surface Sa2 of the hat shape in the lower longitudinal beam outer member 12, the side surface Sb2 deforms outward from the concave-convex shape portion 3. That is, as described above, the curvature of the bent portion (the bulge of the side surface Sb2) in the hat shape of the lower longitudinal beam outer member 12 increases, and the deformation range increases.

[0111] Therefore, the lower longitudinal beam outer member 12 can disperse the stress generated by the side collision load input over a large area, avoiding cracking caused by stress concentration.

[0112] Furthermore, if the height H1 of the concave-convex shape 3 of the side Sb2 is greater than the plate thickness T1 of the outer member 12 of the lower longitudinal beam, the side Sb2 may sometimes deform rapidly starting from the concave-convex shape, thus failing to absorb the collision load repeatedly and reducing the collision performance.

[0113] In contrast, the lower longitudinal beam outer member 12 of this embodiment can achieve stable deformation of the side Sb2 by forming a small height such that the height H1 of the concave-convex shape portion 3 is less than or equal to the plate thickness T1. Therefore, it can simultaneously achieve crack prevention and improve collision performance (absorption performance of side collision load).

[0114] In addition, the lower longitudinal beam outer member 12 of the body frame structure S is formed such that the height H1 of the concave-convex shape portion 3 is formed below the plate thickness T1 of the lower longitudinal beam outer member 12, thereby making the forming easier.

[0115] Furthermore, by miniaturizing the height H1 of the concave-convex shape portion 3 in the lower longitudinal beam outer member 12 of the chassis frame structure S, unlike conventional chassis components (for example, see Patent Document 1), the cross-sectional perimeter can be shortened. As a result, the chassis frame structure S can contribute to the reduction of vehicle body weight.

[0116] Furthermore, since the lower longitudinal beam outer member 12 of the body frame structure S is obtained by miniaturizing the height H1 of the concave-convex shape portion 3, it can be easily obtained using a conventional stamping equipment even if it is a high-strength steel plate with low material ductility and without the use of a large-scale stamping forming equipment.

[0117] In addition, the lower longitudinal beam outer member 12 of the body frame structure S has a miniaturized concave-convex shape part 3, so it can be arranged in a limited space such as the inner side of the outer panel that constitutes the exterior surface of the body 10, which can improve the design freedom of the body 10.

[0118] As described above, according to this embodiment, a vehicle frame structure S can be provided that improves the collision safety performance of the vehicle body, achieves weight reduction unlike previous methods, and facilitates the manufacture of the lower longitudinal beam outer member 12 (frame component). Furthermore, this contributes to the development of sustainable transportation systems.

[0119] In addition, the concave-convex shape portion 3 is formed in a range that is rearward of the joint C1 between the lower longitudinal beam outer member 12 and the front pillar 2, and forward of the joint C2 between the lower longitudinal beam outer member 12 and the rear wheel arch 6.

[0120] In a vehicle frame structure S having such a lower longitudinal beam outer member 12, when a ball-side collision occurs, a larger load is applied to the central portion of the lower longitudinal beam outer member 12 compared to the joint C1 between the front pillar 2 (i.e., the front end of the lower longitudinal beam outer member 12) and the joint C2 between the rear wheel arch 6 (i.e., the rear end).

[0121] Furthermore, in the lower longitudinal beam outer member 12, the concave-convex shape portion 3 is formed in a region that is rearward compared to the joint portion C1 with the front pillar 2 and forward compared to the joint portion with the rear wheel arch. This concave-convex shape portion 3 suppresses cracking relative to the central portion where a larger load is applied. Additionally, the front and rear ends of the lower longitudinal beam outer member 12, which does not have the concave-convex shape portion 3, can be more firmly joined to the front pillar 2 or the rear wheel arch 6 over a wider range. Therefore, the load input to the central portion is efficiently transferred to the front pillar 2 and the rear wheel arch 6, thereby effectively aiding in the absorption of the input load.

[0122] In other words, based on the body frame structure S with such a lower longitudinal beam outer member 12, it is possible to simultaneously achieve crack prevention of the lower longitudinal beam outer member 12 and improve its collision performance (side collision load absorption performance).

[0123] Furthermore, in the lower longitudinal beam outer member 12 of the body frame structure S, there is a ridge 12a formed by a curved surface between the top surface Sa2, which forms a hat shape, and the side surface Sb2. In addition, the concave-convex shape portion 3 is formed adjacent to the ridge 12a via the flat portion 12b or without the flat portion 12b.

[0124] According to such a lower longitudinal beam outer member 12, by forming a curved surface to increase strength, the ridge 12a can preferentially promote the deformation of the side surface Sb2 adjacent to the ridge 12a.

[0125] Furthermore, according to this type of lower longitudinal beam outer member 12, after the load is firmly borne by the high-strength edge 12a, the side surface Sb2 can deform over a large range, so the load absorption efficiency will not decrease, and the cracking of the lower longitudinal beam outer member 12 caused by local stress concentration can be suppressed.

[0126] Furthermore, in the lower longitudinal beam outer member 12 of such a body frame structure S, the concave-convex shape portion 3 is formed by displacement towards the top surface Sa2 compared to the center of the side surface Sb2.

[0127] According to such a lower longitudinal beam outer member 12, the side Sb2 can be deformed outward from the early stage when it is deformed under load, thus making the curvature of the bend (the bulge of the side Sb2) in the hat shape more reliably increase and the deformation range larger.

[0128] Furthermore, in the lower longitudinal beam outer member 12 of such a body frame structure S, the concave-convex shape portion 3 extends parallel to the ridge portion 12a.

[0129] According to the lower longitudinal beam outer member 12, when a load is applied, the side Sb2 is deformed smoothly and stably from the load-bearing part in sequence, thus making the curvature of the bending part (the bulge of the side Sb2) larger and the deformation range larger more reliably.

[0130] In addition, the lower longitudinal beam outer component 12 is a stamped product of high-tensile steel plate.

[0131] Generally, it is known that high-tensile steel sheets, while possessing high strength, conversely lack material ductility, making them difficult to stamp. Furthermore, it is known that frame components made of high-tensile steel sheets are prone to fracture under relatively large impact loads.

[0132] In contrast, the concave-convex shape portion 3 in the lower longitudinal beam outer member 12 of this embodiment is formed with a small height H1 (plate thickness T1 or less), so that even high-tensile steel plates lacking material ductility can be easily stamped.

[0133] Furthermore, as described above, the lower longitudinal beam outer member 12 has a large curvature and a large deformation range during load input, thus effectively suppressing cracking even when using high-tensile steel plates. Additionally, the lower longitudinal beam outer member 12, made of high-tensile steel plates, eliminates the need for reinforcing components such as stiffeners, enabling lightweighting of the chassis frame structure S.

[0134] Furthermore, the concave-convex shape 3 in the lower longitudinal beam outer member 12 can be formed by a wave-shaped part formed by rebound.

[0135] The concave-convex shape 3 of the lower longitudinal beam outer member 12 is formed by a small height H1 (less than the plate thickness T1) as described above, thereby becoming the starting point for the deformation of the side Sb2 to simultaneously achieve the improvement of crack prevention and impact performance (side impact load absorption performance).

[0136] Such a small height H1 concave-convex shape 3 can be formed by a small wavy layer difference generated by the rebound after stamping. Such a lower longitudinal beam outer member 12 can easily form the concave-convex shape 3 even when using high-tensile steel sheet, improving productivity and helping to reduce forming costs.

[0137] The above describes this embodiment, but the present invention is not limited to the above embodiment and can be implemented in various ways.

[0138] Figure 9 This is a partial sectional view of the lower longitudinal beam outer member 12 in the modified example.

[0139] like Figure 5 As shown, in the lower longitudinal beam outer member 12 of the above embodiment, the protrusion 32a protruding inside the recess 32 has the same height as the side surface Sb2.

[0140] In contrast, such as Figure 9 As shown, in the modified example of the lower longitudinal beam outer member 12, the protrusion 32a protrudes inward from the height H2 below the plate thickness T1 of the longitudinal beam outer member 12 below the side Sb2.

[0141] According to this modified example, the lower longitudinal beam outer member 12 can further increase the extension of the concave-convex shape portion 3 when a side impact load is input. As a result, the lower longitudinal beam outer member 12 can further improve the absorption performance of side impact loads.

Claims

1. A chassis frame structure having a frame component formed with a hat-shaped cross-section, characterized in that, The top surface and the side surface that constitute the shape of the hat have a wave-like convex-concave shape formed by alternating and continuous convex portions facing outwards and concave portions facing inwards. The concave-convex shape is formed such that the height from the side to the top of the convex shape is less than or equal to the thickness of the frame component.

2. The chassis frame structure according to claim 1, characterized in that, The top surface and the side surface that constitute the shape of the hat have an edge formed by a curved surface. The concave-convex shape portion is formed adjacent to the flat portion and the ridge portion, or it is formed adjacent to the ridge portion without the flat portion being sandwiched.

3. The chassis frame structure according to claim 1, characterized in that, The concave-convex shape is located between the center of the side surface and the top surface when viewed in cross-section of the hat shape.

4. The chassis frame structure according to claim 2, characterized in that, The concave-convex shape is located between the center of the side surface and the top surface when viewed in cross-section of the hat shape.

5. The chassis frame structure according to claim 2, characterized in that, The concave-convex shape extends parallel to the ridge that extends along the long side of the frame component.

6. The chassis frame structure according to any one of claims 1 to 5, characterized in that, The frame component is a stamped product made of high-tensile steel sheet.

7. The chassis frame structure according to any one of claims 1 to 5, characterized in that, The frame component is the outer part of the lower longitudinal beam that extends in the front-rear direction on the side of the vehicle body.

8. The chassis frame structure according to claim 7, characterized in that, The front end of the outer part of the lower longitudinal beam is connected to the front pillar, and the rear end is connected to the rear wheel arch. The concave-convex shape is formed in a range that is rearward of the joint between the outer part of the lower longitudinal beam and the front pillar, and forward of the joint between the outer part of the lower longitudinal beam and the rear wheel arch.

Images