JPH1143069A - Strength member for automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a strength member for an automobile which can increase the absorbing amount of the impact energy of a vehicle, without accompanying the increase of the plate thickness and the large size of the cross section. SOLUTION: A longitudinal bead 16 extending in the longitudinal direction of a vehicle is formed to a pair of opposing surfaces 10a and 10b of a long size side member 10 with a polygonal cross section. In the longitudinal bead 16, recessed parts 16a recessed to the inner side to the surfaces 10a and 10b, and projection parts 16b expanded to the outer side, are repeated alternately continuously. A buckling is generated at the border position 20 of the recessed part and the projection part 16b, so as to deform the section alternately by making the border position 20 as the border, and at the same time, a buckling is generated at about the central part between the border position 20 and the neighboring border position 20, so as to absorb the impact energy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a strength member such as a front side member of an automobile.

[0002]

2. Description of the Related Art Conventionally, as this kind of front side member, there is one disclosed in Japanese Utility Model Laid-Open No. 6-49270.

[0003]

However, in the strength member described in this publication, a bead extending in the vehicle front-rear direction is provided at the center of the side surface of the strength member, and the bead is provided when an impact load is applied. The structure is designed to absorb the impact energy by crushing the part, but this structure absorbs the impact energy only at the antinode of the buckling wave at the center of the bead, so the amount of impact energy absorbed If this is to be increased, the thickness of the strength member is increased and the cross section is enlarged, which causes a problem of increasing the weight of the vehicle and increasing the size of the vehicle.

[0004] The present invention has been made in view of such a problem, and the inventions according to claims 1 to 4 increase the amount of impact energy absorbed by a vehicle without increasing the plate thickness or enlarging the cross section. It is an object of the present invention to provide a strength member for an automobile that can be used.

[0005]

In order to achieve the above object, the invention according to the first aspect of the present invention is directed to a vehicle having a long strength member having a polygonal cross section, which is provided with a bead to absorb impact energy at the time of a collision. In the member, a longitudinal bead extending in the longitudinal direction of the strength member is formed on a pair of opposite surfaces of the strength member, and the longitudinal bead has a concave portion and a convex portion continuously and alternately with respect to the surface. It is repeated, buckling occurs at the boundary part between the concave part and the convex part at the time of collision, the cross section is alternately deformed at the boundary part, and the boundary part between the boundary part and the adjacent boundary part It is characterized by absorbing impact energy by causing buckling at a substantially central portion.

When an impact load acts in the longitudinal direction of the strength member, the boundary between the concave portion and the convex portion of the longitudinal bead buckles. The pair of opposing surfaces on which the longitudinal beads are formed are bounded such that the portions where the concave portions of the longitudinal beads are formed indent each other and the portions where the convex portions of the long beads are formed bulge outward from each other. The cross section of the strength member is deformed around the part. In this way, when the energy is concentrated at each boundary portion and the deformation of the cross section occurs alternately, next, buckling starts to occur at a substantially central portion between the boundary portion and the adjacent boundary portion, and the inwardly recessed portion is started. The central portion swells outward, and the central portion of the outwardly swelling portion is depressed inward.
Thus, the boundary portion between the concave portion and the convex portion of the long bead,
Buckling occurs between the boundary portion and the substantially central portion of the adjacent boundary member to absorb impact energy.

According to a second aspect of the present invention, in the first aspect, the other surface of the strength member, which forms an angle with the pair of opposing surfaces, extends perpendicularly to the longitudinal bead. A bead is formed, and the orthogonal bead is provided at a substantially central portion in the longitudinal direction of at least one of the concave portion or the convex portion of the longitudinal bead, and the concave or convex portion of the longitudinal bead provided with the orthogonal bead. It is characterized in that it has one of the concavo-convex shape that matches the concavo-convex shape of the shape portion.

When the boundary between the concave portion and the convex portion of the longitudinal bead buckles and the pair of opposing surfaces on which the longitudinal bead is formed is deformed so as to be depressed inward or swelled outward, the formation of the elongated bead is performed. The other surface that forms an angle with the formed surface deforms opposite to the surface on which the longitudinal bead is formed. Since the orthogonal bead is formed on the other surface that forms an angle with the surface on which the longitudinal bead is formed, the orthogonal bead triggers the substantially central portion between the boundary portion and the adjacent boundary portion to be depressed inward. The bulge begins to bulge outwardly at the approximate center, or the bulge begins to bulge inwardly at the approximate center.

[0009] Thus, triggered by the orthogonal bead,
A boundary part where the concave part and the convex part of the long bead are interchanged,
In a substantially central part between the boundary part and the adjacent boundary part,
Buckling will occur. According to a third aspect of the present invention, in the first aspect of the invention, at least one of the pair of facing surfaces of the strength member further includes an orthogonal bead extending in a direction substantially orthogonal to the longitudinal bead. The orthogonal bead is provided at a substantially central portion in the longitudinal direction of at least one of the concave portion or the convex portion of the longitudinal bead, and the concave portion or the convex portion of the longitudinal bead provided with the orthogonal bead. It is characterized in that it has any one of the concavities and convexities opposite to the concavo-convex shape.

When the boundary portion between the concave portion and the convex portion of the longitudinal bead buckles and the pair of opposing surfaces on which the longitudinal bead is formed is deformed so as to be depressed inward or swelled outward, the longitudinal bead is formed. Since the orthogonal bead is formed on the surface, the substantially central portion between the boundary portion and the adjacent boundary portion is triggered by this orthogonal bead, and the inwardly concave portion starts to bulge outward at the approximately central portion. Or the outwardly bulging portion begins to dent inward at a substantially central portion thereof.

Thus, the orthogonal bead triggers
A boundary part where the concave part and the convex part of the long bead are interchanged,
In a substantially central part between the boundary part and the adjacent boundary part,
Buckling will occur. According to a fourth aspect of the present invention, in the second or third aspect, the width and the depth of the longitudinal bead are larger than the width and the depth of the orthogonal bead.

[0012]

According to the first aspect of the present invention, buckling occurs at the boundary between the concave portion and the convex portion of the longitudinal bead and at the approximate center of the boundary member adjacent to the boundary. Buckling can be performed at many portions, and therefore, the amount of impact energy absorbed by the vehicle can be increased without increasing the plate thickness or increasing the cross section.

According to the second aspect of the present invention, in addition to the effect according to the first aspect, a boundary portion where a concave portion and a convex portion of a long bead are interchanged, and Buckling can be surely caused at and near the center portion between the adjacent boundary portions. According to the third aspect of the present invention, in addition to the effect according to the first aspect, a boundary part where the concave part and the convex part of the long bead are replaced by the orthogonal bead is adjacent to the boundary part. Buckling can be surely caused at a substantially central portion between the boundary portions.

Since the orthogonal beads are provided on the same surface as the longitudinal beads, both beads can be formed in the same step, and thus the number of manufacturing steps can be reduced. According to the invention described in claim 4, in addition to the effect according to claim 2 or 3, since the width and depth of the longitudinal bead are larger than the width and depth of the orthogonal bead, the front and rear of the strength member in the vehicle are provided. When an impact load acts in the direction, the longitudinal bead first buckles the boundary portion between the concave portion and the convex portion, and then, triggered by the orthogonal bead, the substantially central portion between the boundary portion and the adjacent boundary portion is seated. Can succumb.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing a first embodiment of a strength member of an automobile according to the present invention. In the figure,
UPR indicates above the vehicle, and FR indicates forward of the vehicle. In the figure, a side member 10 which is a strength member of an automobile has a polygonal cross section formed by joining a member 12 having a U-shaped cross section and a closing plate 14 for closing the opening having the U-shaped cross section. In this example, it is a long strength member having a substantially square (closed) cross section. It is arranged on both sides of the vehicle and extends in the vehicle front-rear direction.

A central portion h / 2 of a width h in the vehicle width direction of a pair of opposing surfaces 10a and 10b (in this example, upper and lower surfaces of the member 12 having a U-shaped cross section) forming a closed cross section of the side member 10. Are formed with longitudinal beads 16 extending in the longitudinal direction, that is, the longitudinal direction of the vehicle. The long bead 16 is formed of a concave portion 16a and a convex portion 16b that are continuously and alternately repeated. That is, in this example,
The surface 10a, 10a
b, a concave portion 16a which is depressed inward with respect to b, and from the next 2L to 4L, a convex portion 16b which bulges outward with respect to the surfaces 10a and 10b.
a and the convex portions 16b are continuously and alternately repeated. At the boundary portion 20 between the concave portion 16a and the convex portion 16b,
The ridge line of the concave portion 16a and the convex portion 16b is continuous so that there is no bending point.

Further, the surface 10 of the side member 10
a, 10b and other surface 10 forming an angle (in this example, 90 degrees)
At c and 10d, orthogonal beads 18 extending in a direction substantially orthogonal to the vehicle front-rear direction, that is, in this example, extending in the vehicle vertical direction are formed. However, in FIG. 1, the orthogonal beads 18 on the surface 10b are used.
Cannot be seen. A plurality of orthogonal beads 18 are provided apart from each other in the vehicle longitudinal direction, and the position of each orthogonal bead 18 is provided at a substantially central portion of the concave portion 16a of the long bead 16 in the vehicle longitudinal direction. Therefore, in the example of the drawing, the side members 10 are provided at L, 5L,... From the front end. And the orthogonal bead 18 matches the concave and convex shape of the concave portion 16a provided with the orthogonal bead 18, and the surfaces 10c, 10d
Has a concave shape depressed inward.

The width w and depth d of the long bead 16 are
The width W and the depth D of the orthogonal bead 18 are set to be larger. With reference to FIG. 2, a description will be given of a deformation of the strength member of the automobile configured as described above, which occurs at the time of collision. FIG.
Shows the state of deformation of the surfaces 10c and 10d on which the orthogonal beads 18 are provided.

First, when a force acts from the front end of the side member 10 in the vehicle longitudinal direction, the longitudinal bead 16 is set to have a greater depth and width than the orthogonal bead 18.
The long bead 16 allows the concave portion 16 of the long bead 16 to be formed.
A boundary portion 20 between a and the convex portion 16b starts to buckle (FIG. 2A). In the surface 10a and the surface 10b, the portion of the long bead 16 where the concave portion 16a is formed is recessed inward, and the portion of the long bead 16 where the convex portion 16b is formed bulges outward. Also, with this buckling, the surface 1
0c and 10d have faces 10a and 10b on the boundary portion 20 even though the longitudinal beads 16 are not formed.
Deforms the opposite. That is, the portion corresponding to the portion where the surfaces 10a and 10b are concave inward swells outward, and the portion where the surfaces 10a and 10b bulge outward is concave inward. In this way, the cross section of the side member 10 is deformed around the boundary portion 20 (FIG. 2B).

In this way, when the energy is concentrated near each of the boundary portions 20 and the cross section is alternately deformed, the surface between the boundary portion 20 and the adjacent boundary portion 20 receives an oblique force from the boundary portion 20. Then, buckling starts to occur in the substantially central portions 22a and 22b between the boundary portion 20 and the adjacent boundary portion 20. That is, in the surfaces 10a and 10b, the central portion 22a of the inwardly concave portion swells outward, and the central portion 22b of the outwardly swelled portion starts to dent inward. In addition, in the surfaces 10c and 10d, the central portion 22a of the outwardly swelling portion is depressed inward, and the central portion 22b of the inwardly depressed portion starts to swell outward (FIG. 2).
(C)). At this time, the concave portions 1 are formed on the surfaces 10c and 10d.
Since the orthogonal bead 18 is provided at the central portion 22a of the concave portion 16a corresponding to the central portion 2a, the orthogonal bead 18 triggers the central portion 2 of the outwardly swelling portion.
In the case of 2a, the deformation of the inward dent is promoted, resulting in buckling. Also, the central portion 22b of the inwardly recessed portion is the central portion 2b.
Buckling occurs due to the buckling of 2a. Thus, as shown in FIG. 2D, the boundary portion 20 and the central portions 22a, 22b
Buckling occurs.

As described above, the concave portion 16a and the convex portion 16b
Is provided, the buckling occurs at the boundary portion 20 and the substantially central portions 22a and 22b between the boundary portion 20 are provided.
In this case, buckling also occurs, so that buckling can be performed at more locations than the locations of the boundary portions 20 of the unevenness. Therefore,
The amount of impact energy absorbed by the vehicle can be increased without increasing the plate thickness or increasing the cross section.

Next, FIG. 3 is a perspective view showing a second embodiment of a strength member of an automobile according to the present invention. In the figure,
The same parts as those in the first embodiment are denoted by the same reference numerals,
The detailed description is omitted. The present embodiment is different from the first embodiment in that the longitudinal beads 26 are provided on the same surfaces 10c and 10d as the orthogonal beads 28,
Longitudinal beads 26 extending in the longitudinal direction, that is, in the vehicle front-rear direction, are formed at central portions a / 2 of the height a of 0c and 10d, respectively. From the front end of the side member 10 up to 2L is a convex portion 26a bulging outward with respect to the surfaces 10c and 10d, and from the next 2L to 4L is a concave portion concaved inward with respect to the surfaces 10c and 10d. Part 26b
The convex portions 26a and the concave portions 26b are sequentially and alternately repeated. At the boundary portion 30 between the convex portion 26a and the concave portion 26b, the convex portion 26a and the concave portion 2
The ridge line 6b is continuous so that there is no bending point.

A plurality of orthogonal beads 28 extending in the vertical direction of the vehicle on the surfaces 10c and 10d are provided apart from each other in the longitudinal direction of the vehicle.
The protruding portion 26 a of the long bead 26 is provided at a substantially central portion in the vehicle front-rear direction. Therefore, in the example of the drawing, the side members 10 are provided at L, 5L,... From the front end. The orthogonal bead 28 has a surface 10 c, 1, opposite to the uneven shape of the convex portion 26 a provided with the orthogonal bead 28.
It has a concave shape that is recessed inward with respect to 0d.

The width w and the depth d of the long bead 26 are
The width W and the depth D of the orthogonal beads 28 are set to be larger than those in the first embodiment. With reference to FIG. 4, a description will be given of deformation of the strength member of the automobile configured as described above, which occurs at the time of collision. FIG. 4 shows a longitudinal bead 2
6 shows a state of deformation of surfaces 10c and 10d provided with 6 and orthogonal beads 28.

First, FIG. 4A shows the normal surfaces 10c, 1c.
0d cut along the plane crossing the long bead 26 3
4 and a view 36 cut along a plane parallel thereto. As in the first embodiment, the side member 1
When a force acts from the front end in the front-rear direction of the vehicle 0, a boundary portion 30 between the convex portion 26a and the concave portion 26b of the longitudinal bead 26 is formed.
Begins to buckle (FIG. 4B). The surface 10c and the surface 10d are formed such that the portions of the long beads 26 where the convex portions 26a are formed bulge outward from each other, and the concave portions 2 of the long beads 26 are formed.
The portions where 6b are formed are recessed inward from each other. Thus,
When energy is concentrated near each boundary part 30 and deformation of the cross section occurs alternately, the boundary part 3 adjacent to the boundary part 30
The surface between 0 and 0 receives a diagonal force from the boundary portion 30,
Further, triggered by the orthogonal beam 28, the boundary portion 3
0 and a substantially central portion 32a, 32 between adjacent boundary portions 30
Buckling begins to occur in b (FIG. 4 (c)). The central portion 32a of the outwardly swelled portion promotes the deformation of the inward dent, resulting in buckling. In addition, the central portion 32b of the inwardly concave portion also buckles due to the buckling of the central portion 32a.
In this way, as shown in FIG. 4D, buckling occurs at the boundary portion 30 and the central portions 32a and 32b. Therefore, the amount of impact energy absorbed by the vehicle can be increased without increasing the thickness or the cross section.

In the second embodiment, since the orthogonal beads 28 are provided on the same surfaces 10c and 10d as the longitudinal beads 26, the same steps are performed when the member 12 having a U-shaped cross section is press-formed from a flat plate. Since both the beads 26 and 28 can be formed in the first embodiment, the number of manufacturing steps can be reduced as compared with the first embodiment, and the manufacturing can be facilitated.

In each embodiment, the orthogonal beads 18,
Although the example in which the 28 is provided has been described, the present invention is not limited to this.
Even in the case of providing only 6, 26, the central portions 22, 32 can be similarly buckled by the buckling of the boundary portions 20, 30. Further, in each of the embodiments, the orthogonal beads 18 and 28 are provided on the facing surfaces. However, the present invention is not limited to this, and the orthogonal beads 18 and 28 may be provided on only one surface. Further, in each of the embodiments, the orthogonal beads 18 and 28 are provided corresponding to the concave portion 16a or the convex portion 26a, but the orthogonal beams 18 and 28 may be provided only in the convex portion 16b or the concave portion 26b. It is possible. Further, the concave portion 16a and the convex portion 16b or the convex portion 26a
It is also possible to provide orthogonal beads 18 and 28 respectively in the concave portion 26b.

Further, in each of the embodiments, the strength member having a rectangular cross section has been described, but the present invention is not limited to this.
The present invention can be applied to a strength member having a polygonal cross section larger than a quadrangle. When the longitudinal beads and the orthogonal beads are provided on different surfaces as in the first embodiment, the surfaces on which the longitudinal beads and the orthogonal beads are provided need only have an angle.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a first embodiment of a strength member of an automobile according to the present invention.

2 (a) to 2 (d) are explanatory views showing a state of deformation occurring at the time of collision of the strength member of FIG. 1. FIG.

FIG. 3 is a perspective view illustrating a second embodiment of a strength member of an automobile according to the present invention.

4 (a) to 4 (d) are explanatory views showing a state of deformation occurring when the strength member of FIG. 3 collides.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Side member (strength member) 10a, 10b A pair of face 10c 10d The other face 16 Long bead 16a Concave part 16b Convex part 18 Orthogonal bead 20 Boundary part 22a, 22b Substantially the center between a boundary part and an adjacent boundary part Part 26 Longitudinal bead 28 Orthogonal bead 26a Convex part 26b Concave part 30 Boundary part 32a, 32b Substantially the center part between the boundary part and the adjacent boundary part

Claims (4)

[Claims] 1. A strength member for an automobile that absorbs impact energy at the time of a collision by providing a bead on a long strength member having a polygonal cross section, wherein the strength member extends in a longitudinal direction of a pair of opposite surfaces of the strength member. The long bead is formed by repeating a concave portion and a convex portion continuously and alternately with respect to a surface, and a boundary portion between the concave portion and the convex portion at the time of collision. The buckling occurs at the boundary, the cross section is alternately deformed at the boundary, and the buckling occurs at the approximate center between the boundary and the adjacent boundary, thereby absorbing the impact energy. Automotive strength members. 2. An orthogonal bead extending in a direction substantially orthogonal to a longitudinal bead is formed on another surface of the strength member that forms an angle with the pair of opposed surfaces, and the orthogonal bead is formed of the longitudinal bead. At least one of the concave portion or the convex portion is provided at a substantially central portion in the longitudinal direction, and the orthogonal bead has any of the concave and convex shapes corresponding to the concave and convex portions of the longitudinal bead provided with the orthogonal beads. The strength member for an automobile according to claim 1, wherein the strength member is provided. 3. An orthogonal bead extending in a direction substantially orthogonal to a longitudinal bead is formed on at least one of the pair of opposed surfaces of the strength member, and the orthogonal bead is formed of the longitudinal bead. At least one of the concave part or the convex part is provided at a substantially central portion in the longitudinal direction, and the orthogonal bead is formed in any one of the concave and convex shapes opposite to the concave or convex shape of the longitudinal bead provided with the orthogonal bead. The strength member for an automobile according to claim 1, wherein the strength member is provided. 4. The strength member for an automobile according to claim 2, wherein a width and a depth of the longitudinal bead are larger than a width and a depth of the orthogonal bead.