Strength member for vehicle

Abstract

To provide a strength member for vehicle in which collision energy absorption efficiency and member assembly efficiency are enhanced.SOLUTION: There is provided a long strength member for vehicle, the strength member for vehicle comprises: a first member 13; and a second member 14, these members having a cross section crossing in a longitudinal direction and being formed in a groove-shape. The strength member for vehicle has a closed cross section. The first member 13 and the second member 14 comprise respectively: bottom faces 13b, 14b formed in a groove-shape; walls 13c, 13d / 14c, 14d standing from both side edges of the bottom face 13b, 14b; and an opening 13a, 14a. In an arrangement state where the openings 13a, 14b face each other, a first overlapping part 15 where, an inner face of one wall 13c of the first member 13 and an outer face of one wall 14c of the second member 14 contact and overlap, a second overlapping part 16 where an outer face of the other wall 13d of the first member 13 and an inner face of the other wall 14d of the second member 14 contact and overlap, and junctions 17, 18, are provided.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a strength member for a vehicle. [Background technology]

[0002] Conventionally, vehicle bodies are provided with structures for receiving collision loads during a vehicle collision. For example, bumper structures provided at the front or rear of a vehicle are equipped with bumper reinforcements that act as core materials to absorb collision energy. Patent Document 1 discloses, as an example of a bumper reinforcement, a structure in which a steel sheet material is fixed by spot welding to the end portion of a steel base member having a hat-shaped cross section. In other words, this bumper reinforcement has a closed cross section formed by two members.

[0003] Patent Document 2 discloses an example of a bumper reinforcement in which two members are joined by rivets to form a closed cross section. In this bumper reinforcement, rivets are applied to a flange portion formed at the end of a member with a hat-shaped cross section. In this way, by combining two members to form a closed cross section, the strength of the bumper reinforcement can be improved. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-37220 [Patent Document 2] Japanese Patent Publication No. 2021-154377 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the bumper reinforcement described in Patent Document 1 or Patent Document 2, spot welding or riveting outside a closed cross section requires, for example, flanges to be provided at the ends of the two components in order to sandwich the joining position with electrodes on both sides. While this has the advantage of making it easy to manage the gap between the two components when assembling them, the size of the closed cross section tends to be limited in order to fit within a design space determined by the relationship between the bumper reinforcement and surrounding components. As a result, there is room for improvement in the strength and collision energy absorption capacity of vehicle strength members.

[0006] The present invention has been devised in view of the above points, and the problem that the present invention aims to solve is to provide a strength member for a vehicle that can improve the efficiency of absorbing collision energy and the efficiency of assembling the member. [Means for solving the problem]

[0007] In order to solve the above problems, the vehicle strength member according to the present invention takes the following measures.

[0008] The first invention of the present invention is a strength member for a vehicle having a closed cross-sectional shape formed by at least two elongated members, and comprising a first member and a second member whose cross section intersecting the longitudinal direction is groove-shaped, and the first member and the second member each have a bottom surface portion forming the groove shape, wall portions standing from both side edges of the bottom surface portion, and an opening portion that is open on the opposite side of the bottom surface portion, and when the openings are arranged facing each other, there is a first overlapping portion where the inner surface of one of the wall portions of the first member and the outer surface of one of the wall portions of the second member are overlapping in abutting contact, a second overlapping portion where the outer surface of the other of the wall portions of the first member and the inner surface of the other of the wall portions of the second member are overlapping in abutting contact, and a joint portion where the abutting wall portions at the first and second overlapping portions are joined.

[0009] The second invention of the present invention is a vehicle strength member of the first invention, wherein, in a cross-sectional view intersecting the longitudinal direction of the vehicle strength member, the first member is arranged on the side receiving the collision load of the vehicle body, and the vertical distance from the joint to the bottom surface of the first member is shorter than the vertical distance from the joint to the bottom surface of the second member.

[0010] A third aspect of the present invention is the vehicle reinforcing member according to the second aspect, wherein the joint portion at the first and second overlapping portion is joined by laser welding.

[0011] A fourth aspect of the present invention is the vehicle reinforcing member of the third aspect, wherein the bottom surface of at least one of the first member and the second member has a recessed bead formed in the longitudinal direction.

[0012] A fifth aspect of the present invention is the vehicle reinforcing member of the fourth aspect, wherein the first member and the second member each have a recessed bead formed in the longitudinal direction on the bottom surface thereof.

[0013] The sixth invention of the present invention is a vehicle strength member of the fifth invention, wherein a concave bead formed on the bottom surface of the first member abuts against a concave bead formed on the bottom surface of the second member, and the first member and the second member are joined at the abutment portion of the concave beads.

[0014] A seventh aspect of the present invention is a vehicle strength member according to any one of the first to sixth aspects of the present invention, wherein the vehicle strength member is applied to a bumper reinforcement. [Effects of the Invention]

[0015] According to the above-described means of the present invention, it is possible to provide a strength member for a vehicle that can improve the efficiency of absorbing collision energy and the efficiency of assembling the member. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 2 is a schematic diagram showing the position of the bumper device relative to the vehicle body. [Figure 2] 1 is a perspective view showing an outline of a vehicle strength member according to a first embodiment. [Figure 3] 1 is a plan view showing an outline of a vehicle strength member according to a first embodiment. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Figure 5] FIG. 3 is a cross-sectional view schematically showing the orientation of a set of a first member and a second member. [Figure 6] FIG. 10 is a cross-sectional view schematically showing a step of laser bonding the first and second overlapping portions. [Figure 7] 10 is a diagram showing a cross-sectional shape of a vehicle strength member according to a second embodiment. FIG. [Figure 8] 10A and 10B are diagrams showing a cross-sectional shape of a vehicle strength member according to another embodiment. [Figure 9] FIG. 10 is a cross-sectional view schematically showing the arrangement of two members in a conventional example. DETAILED DESCRIPTION OF THE INVENTION

[0017] First Embodiment An embodiment of the present invention will be described below with reference to the drawings. The vehicle strength member according to this embodiment is a bumper reinforcement 10 provided as a core material of a bumper device 2 provided at the front or rear of a vehicle body 4 of an automobile or the like. Note that the indications of front-rear, left-right, and up-down directions in the illustrations are indications when viewed from the direction of travel of a vehicle such as an automobile.

[0018] <Bumper device 2 and bumper reinforcement 10> First, the arrangement of a vehicle bumper device 2 equipped with a bumper reinforcement 10, which is a strength member for a vehicle, will be described. As shown in Fig. 1, the bumper device 2 is usually arranged in the width direction of the vehicle body 4 at positions in the front and rear of the vehicle body 4.

[0019] The bumper device 2 is made up of a long bumper reinforcement 10, a bumper covering member 6, and a bumper support structure 8. The bumper reinforcement 10 is arranged as a core material to provide strength to the bumper device 2. The bumper covering member 6 is arranged so as to cover the front surface of the bumper reinforcement 10. The bumper covering member 6 is arranged on the outermost surface of the bumper device 2, and is configured with consideration given to appearance. It is usually made of a resin that is suitable for molding designs.

[0020] The bumper support structure 8 is disposed between a frame member (not shown) of the vehicle body 4 and the bumper reinforcement 10, at positions on both sides of the bumper reinforcement 10 in the longitudinal direction (vehicle body width direction). The bumper support structure 8 transmits the collision load received by the bumper reinforcement 10 to the vehicle body 4, and is supported by the vehicle body 4.

[0021] This embodiment will be described taking as an example the case of a bumper reinforcement 10 disposed in the front of a vehicle body 4. In the bumper device 2, a collision load acting on the center position of the bumper device 2 due to, for example, a head-on collision of an automobile is received by the bumper covering member 6, and this load is supported by the bumper reinforcement 10. The load acting on the bumper reinforcement 10 is then received by the vehicle body 4 via the bumper support structure 8.

[0022] As shown in Figures 2 and 3, the bumper reinforcement 10 has an elongated shape, is disposed in the width direction of the vehicle body 4, and is formed in a curved shape with both longitudinal ends recessed. The bumper reinforcement 10 is composed of an elongated first member 13 and a second member 14. The first member 13 and the second member 14 have a groove-shaped cross section intersecting the longitudinal direction. As shown in Figure 4, the bumper reinforcement 10 is arranged so that the openings 13a, 14a of the first member 13 and the second member 14 face each other, and form a substantially rectangular closed cross section in a cross section intersecting the longitudinal direction. In this embodiment, the first member 13 is disposed on the outer side in the fore-and-aft direction of the vehicle body (the side that receives a collision load), and the second member 14 is disposed on the inner side (the side opposite the side that receives the collision load).

[0023] 4, the first member 13 has a first bottom surface portion 13b having a groove-shaped cross section, wall portions 13c and 13d standing upright from both side edges of the first bottom surface portion 13b, and an opening portion 13a that is open on the opposite side of the first bottom surface portion 13b. In this embodiment, the first bottom surface portion 13b is located on the side that receives the collision load (the front side of the vehicle body), and the two wall portions 13c and 13d are located above and below. Here, the "bottom surface portion" refers to the portion of the first member 13 and the second member 14 that has a groove-shaped cross section, and includes cases where the "bottom surface portion" faces any of the front-rear, left-right, and up-down directions depending on the position where the vehicle strength member is installed.

[0024] 2 and 4, the first bottom surface portion 13b is provided with a plurality of recessed beads 13e. The recessed beads 13e are recessed from the outside toward the inside of the first bottom surface portion 13b in the vehicle front-rear direction, and are formed along the longitudinal direction, for example, in the center of the first member 13 (bumper reinforcement 10) in the vehicle width direction.

[0025] 4, the second member 14 has a second bottom surface portion 14b having a groove-shaped cross section, wall portions 14c and 14d standing from both side edges of the second bottom surface portion 14b, and an opening portion 14a that opens on the opposite side of the second bottom surface portion 14b. In this embodiment, the second bottom surface portion 14b is located on the opposite side from the side that receives the collision load, and the two wall portions 14c and 14d are located one above the other.

[0026] The dimensions of the upper and lower wall portions 13c, 13d, 14c, and 14d of the first member 13 and the second member 14 in the fore-and-aft direction of the vehicle body are appropriately set to correspond to the arrangement of the joints 17 and 18 in the first overlapping portion 15 and the second overlapping portion 16 described below.

[0027] The bumper reinforcement 10 is disposed such that the upper and lower wall portions 13c, 13d of the first member 13 and the upper and lower wall portions 14c, 14d of the second member 14 overlap with each other. In this embodiment, the overlapping portion of the upper wall portions 13c, 14c is referred to as a first overlapping portion 15, and the overlapping portion of the lower wall portions 13d, 14d is referred to as a second overlapping portion 16. In the first overlapping portion 15, the inner surface of the upper wall portion 13c of the first member 13 and the outer surface of the upper wall portion 14c of the second member 14 overlap in abutting contact. That is, the upper wall portion 13c of the first member 13 is located on the outside of the closed cross section, and the upper wall portion 14c of the second member 14 is located on the inside. Meanwhile, in the second overlapping portion 16, the outer surface of the lower wall portion 13d of the first member 13 and the inner surface of the lower wall portion 14d of the second member 14 overlap in abutting contact. That is, the lower wall portion 13d of the first member 13 is located on the inside of the closed cross section, and the lower wall portion 14d of the second member 14 is located on the outside.

[0028] The bumper reinforcement 10 has joints 17 and 18 at the first and second overlapping portions 15 and 16, respectively. As shown in FIGS. 2 and 4, the abutting upper wall portions 13c and 14c are joined at an arbitrary location in the first overlapping portion 15, and the abutting lower wall portions 13d and 14d are joined at an arbitrary location in the second overlapping portion 16. The joints 17 and 18 are each spot-welded, for example, by laser screw welding (LSW). The positions of the joints 17 and 18 indicated by crosses are merely illustrative of the manner in which they are disposed at arbitrary locations in the first overlapping portions 15 and 16, and do not specify the number of joints. The joints 17 and 18 may also be joined by other methods, such as laser welding or arc welding.

[0029] 4, the joints 17, 18 are each disposed closer to the side of the vehicle body 4 that receives the collision load in a cross section intersecting the longitudinal direction of the bumper reinforcement 10. That is, the positions of the joints 17, 18 are set so that the vertical distance L1 from the joints 17, 18 to the first bottom surface portion 13b of the first member 13 is shorter than the vertical distance L2 from the joints 17, 18 to the second bottom surface portion 14b of the second member 14. Note that the vertical distance L1 from the joints 17, 18 to the first bottom surface portion 13b is the vertical distance from the joints 17, 18 to the outermost surface of the first bottom surface portion 13b.

[0030] <Manufacturing method of Bumper Reinforcement 10> Next, a manufacturing process for the bumper reinforcement 10 described above will be described. The first member 13 and the second member 14 constituting the bumper reinforcement 10 are formed by press-forming a metal member such as a steel plate in a forming process. As shown in FIGS. 3 and 4, the first member 13 is elongated, and its cross section intersecting the longitudinal direction is groove-shaped. The first member 13 has a first bottom surface 13b, walls 13c and 13d standing from both side edges of the first bottom surface 13b, and an opening 13a that opens on the side opposite the first bottom surface 13b. A plurality of recessed beads 13e are formed on the first bottom surface 13b. The second member 14 is elongated, and its cross section intersecting the longitudinal direction is groove-shaped. The second member 14 has a second bottom surface 14b, walls 14c and 14d standing from both side edges of the second bottom surface 14b, and an opening 14a that opens on the side opposite the second bottom surface 14b.

[0031] As shown in FIG. 5, the first member 13 and the second member 14 press-formed in the molding process are combined in the assembling process so that the openings 13a, 14a of the first member 13 and the second member 14 face each other. For example, the first member 13 is combined from an upward diagonal direction with the second member 14, which has been aligned using a jig or the like. This results in a substantially rectangular closed cross section in a cross section intersecting the longitudinal direction of the bumper reinforcement 10. In the first overlapping portion 15, the upper wall portion 13c of the first member 13 is located on the outside of the closed cross section, and the upper wall portion 14c of the second member 14 is located on the inside. Meanwhile, in the second overlapping portion 16, the lower wall portion 13d of the first member 13 is located on the inside of the closed cross section, and the lower wall portion 14d of the second member 14 is located on the outside.

[0032] 9 , for example, when two vehicle strength members 31 and 32 are arranged such that one member 31 has both wall portions 32c and 32d of the other member 32 positioned inside the other member 31, the dimension between the upper wall portion 31c and the lower wall portion 31d of the one member 31 is larger than the dimension between the upper wall portion 32c and the lower wall portion 32d of the other member 32 in a cross-sectional view intersecting the longitudinal direction, and the two members 31 and 32 have different dimensions. When these members 31 and 32 are joined by laser welding or the like, the dimensional accuracy of the members is further limited. Specifically, if the gap between the two members 31 and 32 is large, good welding quality may not be achieved at the joining position. If the gap is too narrow, the walls of the two members 31 and 32 may interfere with each other when they are joined.

[0033] 4 and 5, the bumper reinforcement 10 according to this embodiment is configured by combining two members 13, 14 so that the wall portions 13c, 13d of the first member 13 and the wall portions 14c, 14d of the second member 14 are positioned alternately. This makes it possible to make the dimension between the upper wall portion 13c and the lower wall portion 13d of the first member 13 the same as the dimension between the upper wall portion 14c and the lower wall portion 14d of the second member 14 in a cross-sectional view intersecting the longitudinal direction of the bumper reinforcement 10, and also makes it possible to set the first member 13 obliquely relative to the second member 14. This relaxes restrictions on the dimensional accuracy and assembly accuracy of the members, making it easier to control accuracy.

[0034] As shown in FIG. 6 , the first member 13 and the second member 14 are spot-welded and integrated at any desired locations in the first and second overlapping portions 15, 16 during the joining process. Laser screw welding (LSW), for example, is used for spot welding. Laser screw welding (LSW) is a welding method that uses laser irradiation to heat the members, and heating is performed from only one side. Furthermore, compared to conventional spot welding, LSW allows for joining in a shorter heating time and a shorter welding pitch. In other words, by using LSW, more spot welds can be arranged and the joints 17, 18 can be joined without gaps, thereby improving the rigidity of the bumper reinforcement 10. Furthermore, because welding can be performed at a higher speed, production efficiency can be improved.

[0035] <Effects of the First Embodiment> Next, the effects of the first embodiment will be described.

[0036] According to this embodiment, the bumper reinforcement 10 (vehicle strength member) has a closed cross section formed by the first member 13 and the second member 14, each of which has a groove-shaped cross section intersecting the longitudinal direction. As a result, when viewed in cross section in the longitudinal direction of the bumper reinforcement 10, a closed cross section is formed with no flange portion on the outside. In other words, the bumper reinforcement 10 is formed with a closed cross section that makes full use of the design space S. Therefore, the strength of the bumper reinforcement 10 can be improved, and energy absorption efficiency is improved.

[0037] In the bumper reinforcement 10 according to this embodiment, the wall portions 13c, 13d of the first member 13 and the wall portions 14c, 14d of the second member 14 are arranged so that they alternately overlap in the vertical direction. This prevents interference between the first member 13 and the second member 14 when they are combined, making it easier to control dimensional accuracy and assembly accuracy. In other words, even when LSW welding or other laser welding that accesses the joining position from one side is selected, it becomes easy to align the two members 13, 14. This makes it possible to improve the assembly efficiency of the members.

[0038] In this embodiment, in a cross-sectional view intersecting the longitudinal direction of the bumper reinforcement 10, the first member 13 is disposed on the side receiving the collision load of the vehicle body 4 (e.g., outside the center in the vehicle body longitudinal direction), and the joint positions are set so that the vertical distance L1 from the joints 17, 18 to the outermost surface of the first bottom surface portion 13b of the first member 13 is shorter than the vertical distance L2 from the joints 17, 18 to the second bottom surface portion 14b of the second member 14. In other words, the joints 17, 18 in the first and second overlapping portions 15, 16 are disposed closer to the side receiving the collision load. The joints 17, 18 are regions with higher strength because the wall portions 13c, 13d, 14c, and 14d are joined while overlapping in the thickness direction. By arranging the high-strength portions closer to the side receiving the collision load than the center of the bumper reinforcement 10 in the vehicle body longitudinal direction, rigidity against deformation and compression can be improved. That is, the collision load of the bumper reinforcement 10 increases, and the energy absorption efficiency can be improved.

[0039] In this embodiment, joints 17, 18 are spot-welded using laser screw welding (LSW) at the first and second overlapping portions 15, 16, respectively. LSW welding can join overlapping members by irradiating a laser from only one side, so it can be applied to the bumper reinforcement 10 in which no flange portion is provided on the outside of the closed cross section formed by the first member 13 and the second member 14. In other words, it is suitable for configuring a closed cross section that makes full use of the design space S of the bumper reinforcement 10.

[0040] The first member 13 of the bumper reinforcement 10 according to this embodiment is provided with a recessed bead 13e formed in the longitudinal direction. By providing the recessed bead 13e on the first member 13 disposed on the side receiving the collision load, it is possible to improve the rigidity and strength against deformation, compression, etc. In other words, it is possible to improve the rigidity and strength of the bumper reinforcement 10.

[0041] Second Embodiment Next, a bumper reinforcement 20 according to a second embodiment will be described. Note that a description of configurations similar to those according to the first embodiment will be omitted, and the description will focus on configurations that are different. FIG. 7 is a diagram showing a cross section intersecting the longitudinal direction of the bumper reinforcement 20. The bumper reinforcement 20 has a first member 23 and a second member 24 that are elongated and have a groove-shaped cross section intersecting the longitudinal direction. The openings 23a, 24a of the first member 23 and the second member 24 are arranged facing each other, forming a closed cross section.

[0042] The first member 23 has a first bottom surface portion 23b, upper and lower wall portions 23c and 23d, and an opening 23a. The first bottom surface portion 23b has a plurality of recessed beads 23e. The recessed beads 23e are formed, for example, along the longitudinal direction in the center of the first member 23 in the vehicle width direction. The second member 24 has a second bottom surface portion 24b, upper and lower wall portions 24c and 24d, and an opening 24a. The second bottom surface portion 24b has a recessed bead 24e. The recessed bead 24e is formed, for example, along the longitudinal direction in the center of the second member 24 in the vehicle width direction, and the center in the up-down direction of the second bottom surface portion 24b is recessed toward the opening 24a. At the location where the recessed beads 24e are formed, the closed cross section of the bumper reinforcement 20 has a B-shape.

[0043] The bumper reinforcement 20 has a first overlapping portion 25 and a second overlapping portion 26. The first overlapping portion 25 overlaps the inner surface of the upper wall portion 23c of the first member 23 and the outer surface of the upper wall portion 24c of the second member 24 in abutting contact with each other. The second overlapping portion 26 overlaps the outer surface of the lower wall portion 23d of the first member 23 and the inner surface of the lower wall portion 24d of the second member 24 in abutting contact with each other. The first and second overlapping portions 25, 26 are spot-welded at selected locations to be integrated. Laser screw welding (LSW), for example, is used for the spot welding.

[0044] In the bumper reinforcement 20, the concave bead 23e formed on the first bottom surface portion 23b (first member 23) that is located in the center in the up-down direction abuts against the concave bead 24e formed on the second bottom surface portion 24b (second member 24). The abutment surfaces (abutment portions) of these concave beads 23e, 24e are configured to be wider to facilitate welding and the like. The abutment surfaces of the concave beads 23e, 24e are joined by, for example, LSW welding, to form a joint 29. The abutment surfaces of the concave beads 23e of the first member 23 and the concave bead 24e of the second member 24 may also be joined by other methods such as laser welding or spot welding.

[0045] As shown in FIG. 8, the bumper reinforcement 20 may be configured such that the recessed bead 24e formed in the second member 24 is shallow so that it does not come into contact with the recessed bead 23e of the first member 23.

[0046] <Effects of the Second Embodiment> The bumper reinforcement 20 according to the second embodiment has the following advantages in addition to the advantages of the first embodiment described above.

[0047] Recessed beads 23e, 24e are formed in the longitudinal direction of the bumper reinforcement 20 on the bottom surfaces 23b, 24b of the first member 23 and the second member 24, respectively. This can improve the rigidity and strength of the bumper reinforcement 20. Furthermore, the recessed bead 23e formed on the bottom surface 23b of the first member 23 and the recessed bead 23e formed on the bottom surface 24b of the second member 24 abut against each other, and the first member 23 and the second member 24 are joined at the abutting portions of the recessed beads 23e, 24e, forming a joint 29. This can further improve the rigidity and strength of the bumper reinforcement 20.

[0048] <Other embodiments> Although specific embodiments of the present invention have been described above, the present invention can be embodied in many different forms.

[0049] The vehicle strength member according to the present invention is not limited to bumper reinforcement, but can also be applied to other vehicle members such as center pillars.

[0050] The positions and shapes of the recessed beads 13e, 23e formed in the first members 13, 23 and the recessed bead 24e formed in the second member 24 can be changed as appropriate.

[0051] The bumper reinforcements 10, 20 (vehicle strength members) according to the above embodiments may be configured by switching the overlapping arrangement of the first members 13, 23 and the second members 14, 24. For example, the second members 14, 24 may be combined with the first members 13, 23 from diagonally above.

[0052] The joining method for the first and second overlapping portions 15, 16, 25, 26 may be laser welding or arc welding.

[0053] <Effects of each invention described in "Means for solving the problems"> Finally, the effects of the above embodiments corresponding to the inventions in the "Means for Solving the Problems" section will be added.

[0054] According to the first aspect of the present invention, two elongated members each having a groove-shaped cross section intersecting the longitudinal direction are overlapped with their openings facing each other. This results in a closed cross section with no flanges on the outside when viewed in longitudinal cross section of the vehicle strength member. In other words, a vehicle strength member having a closed cross section that fully utilizes the design space of the member is configured. This improves the strength of the vehicle strength member and improves energy absorption efficiency. Furthermore, the wall portions of the first and second members are arranged to overlap alternately. This prevents interference between the first and second members when they are combined, making it easier to control dimensional accuracy and assembly accuracy. This means that even when a joining method such as welding is selected for the joining position from one side, it is easy to align the two members. This improves the assembly efficiency of the members.

[0055] According to the second aspect of the present invention, in a cross-sectional view intersecting the longitudinal direction of the vehicle strength member, the first member is disposed on the side receiving the collision load of the vehicle body, and the joining positions are set so that the vertical distance from the joint to the bottom surface of the first member is shorter than the vertical distance from the joint to the bottom surface of the second member. That is, the joints in each of the first and second overlapping portions are disposed closer to the side receiving the collision load. Because the joints where the wall portions are joined together by overlapping each other are high-strength portions, positioning them on the side receiving the collision load can improve rigidity against deformation, compression, and the like. Therefore, the collision load increases, and energy absorption efficiency improves.

[0056] According to the third aspect of the present invention, the joint between the first and second overlapping members is joined by laser welding. That is, welding is performed from one side (outside) of the overlapping first and second members, which is suitable for use as a strength member for a vehicle that does not form a flange on the outside of the closed cross-sectional shape.

[0057] According to the fourth aspect of the present invention, a recessed bead is formed in the bottom surface of at least one of the first member and the second member in the longitudinal direction of the vehicle strength member, thereby improving the rigidity and strength of the vehicle strength member.

[0058] According to the fifth aspect of the present invention, recessed beads are formed in the bottom surface portions of the first and second members in the longitudinal direction of the vehicle strength member, thereby improving the rigidity and strength of the vehicle strength member.

[0059] According to the sixth aspect of the present invention, the recessed bead formed on the bottom surface of the first member and the recessed bead formed on the bottom surface of the second member abut against each other, and the first member and the second member are joined at the abutting portion of the recessed beads, which can further improve the rigidity and strength of the vehicle strength member.

[0060] According to the seventh aspect of the present invention, the vehicle strength member is applied to a bumper reinforcement, thereby providing a bumper reinforcement that has higher rigidity and strength and can efficiently absorb energy. [Explanation of symbols]

[0061] 2 Bumper device 4. Body 6 Bumper covering material 8 Bumper support structure 10 Bumper reinforcement (vehicle strength member) 13 First member 13a opening 13b 1st bottom part (bottom part) 13c Upper wall (wall) 13d Lower wall (wall) 13e concave bead 14 Second member 14a opening 14b 2nd bottom part (bottom part) 14c Upper wall (wall) 14d Lower wall (wall) 15 First overlapping section 16 Second overlapping section 17 Joint 18 Joint 20 Bumper reinforcement (vehicle strength member) 23 First member 23a opening 23b 1st bottom part (bottom part) 23c Upper wall (wall) 23d Lower wall (wall) 23e concave bead 24 Second member 24a opening 24b 2nd bottom part (bottom part) 24c Upper wall (wall) 24d Lower wall (wall) 24e concave bead 25 First overlapping section 26 Second overlapping section 27 Joint 28 Joint 29 Joint L1 Vertical distance from the joint to the first bottom part L2 Vertical distance from the joint to the second bottom surface S design space

Claims

1. A vehicle strength member having a closed cross section formed by at least two elongated members, The device has a first member and a second member each having a groove-shaped cross section intersecting the longitudinal direction, The first member and the second member are Each of the containers has a groove-shaped bottom surface, walls standing from both side edges of the bottom surface, and an opening on the opposite side of the bottom surface, In a state in which the openings face each other, a first overlapping portion in which an inner surface of one of the wall portions of the first member and an outer surface of one of the wall portions of the second member are overlapped in a state of abutting against each other; a second overlapping portion in which an outer surface of the other wall portion of the first member and an inner surface of the other wall portion of the second member overlap in a state of abutting against each other; and a joint portion where the wall portions abutting at the first and second overlapping portions are joined.

2. 2. A vehicle strength member according to claim 1, In a cross-sectional view intersecting the longitudinal direction of the vehicle strength member, the first member is arranged on a side that receives a collision load of the vehicle body, and the vertical distance from the joint to the bottom portion of the first member is shorter than the vertical distance from the joint to the bottom portion of the second member.

3. 3. A vehicle strength member according to claim 2, A strength member for a vehicle, wherein the joint portion at the first and second overlapping portions is joined by laser welding.

4. A vehicle strength member according to claim 3, A strength member for a vehicle, comprising a recessed bead formed in the longitudinal direction on the bottom surface portion of at least one of the first member and the second member.

5. A vehicle strength member according to claim 4, A strength member for a vehicle, the strength member having a recessed bead formed in the longitudinal direction on the bottom surface portion of each of the first member and the second member.

6. A vehicle strength member according to claim 5, A strength member for a vehicle, wherein a concave bead formed on the bottom surface of the first member abuts against a concave bead formed on the bottom surface of the second member, and the first member and the second member are joined at the abutment portion of the concave beads.

7. A vehicle strength member according to any one of claims 1 to 6, The vehicle strength member is applied to a bumper reinforcement.

Images