JPH08183473A - Strength member for vehicle - Google Patents

Abstract

PURPOSE: To set the buckling strength of a plate part between spot-welded points to be not less than the buckling strength of other parts liable to buckle. CONSTITUTION: A flange 101c formed at a channel member 101, and a flange 102c formed at a plate part 102 are adjusted to each other and spot-welded at the specified pitch L to form a long-sized cylindrical strength member of polygonal closed cross section. In the case of the width (c) of the plate part 102 being longer than any other sides forming the polygonal closed cross section, beads 105a, 105b serving as reinforcing parts are formed at the plate part 102, and the positions of these beads are set within the distance (b) from the fixed end of the plate part 102 and within the distance 0.47b<2> /L from the free end of the flange, where (b) is the length of the second long side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a strength member for a vehicle, such as a front side member, which is crushed by a compressive load in the axial direction (longitudinal direction) and absorbs collision energy at the time of collision of the vehicle.

[0002]

2. Description of the Related Art Conventionally, as an example of a vehicle strength member such as a front side member, one shown in FIG. 17 (see Japanese Patent Laid-Open No. 4-126677) is known. The strength member is formed into a closed cross section called a hat cross section by welding together the channel material 101 as the first plate material and the flat plate portion 102 as the second plate material.

The channel member 101 has a U-shaped cross section with one side open, and has a vertical wall surface 101b having a side length b, and two horizontal wall surfaces 101a having a side length a continuous to both ends thereof.
An outwardly bent flange 101c is provided at an end of each of the lateral wall surfaces 101a, and the flat plate portion 102 is aligned with the channel material 101 so as to close the opening. 102c (on the extension of one side that constitutes the closed polygonal cross section) and the channel material 1
No. 01 flange 101c is joined by spot welding with a predetermined pitch L. What is indicated by reference numeral 103 is
It is a spot welding point.

In this strength member, the channel material 1
A bead 104 extending in the axial direction of the strength member is provided on the vertical wall surface 101b of 01. The bead 104 is convex on the outer surface side, and is formed so that the width s gradually increases toward the rear of the strength member. A cross section A of a portion of the strength member including the bead 104 has a shape as shown in FIG.

Further, as shown in FIG.
However, instead of the channel member 101, there is a plate member provided at the central portion in the width direction of the flat plate portion 102. In this case, the cross section B at the portion where the bead 104 is present has a shape as shown in FIG.

[0006]

By the way, if the plate thickness is the same, "the buckling strength of the plate material becomes lower as the side length becomes longer".
Based on the plate buckling theory, that is, in the strength member as shown in FIG. 17, the side length c of the flat plate portion 102 is larger than the longest side length b of the channel material 101 (the actual side of the square section). Length of both ends flanges 102c, 10
2) is longer, and there is no constraint between the spot welding points 103 (= between pitches).
The flat plate portion 102 is under a condition where buckling between tacks (buckling between spot welding points) is very likely to occur.

That is, the channel material 10 having a U-shaped cross section
As shown in FIG. 21, the flat plate portion 102 is likely to buckle between the tacks before 1 reaches the limit strength. Therefore, in the strength member as shown in FIG. 17, although the bead 104 is formed on the vertical wall surface 101b to reinforce the channel member 101, its crushing strength is mainly the flat plate portion 1.
There was a problem that it was governed by the buckling strength between the tacks on the 02 side.

Further, in the cross section shown in FIG.
Since the strength difference between the channel material 101 side reinforced with the beads 104 and the flat plate portion 102 side with respect to the longitudinal centerline cl becomes extremely large, there is a strong tendency to collapse to the flat plate portion 102 side during crushing and stability. There was a problem that the deformation was difficult to proceed in the mode.

Further, in the strength member as shown in FIG. 19, the bead 104 is provided on the flat plate portion 102 side, but since the position of the bead 104 is the center portion in the width direction of the flat plate portion 102, In the flat plate portion up to the free end of the flange 102c, there is a high possibility that buckling between the tacks will occur in the shape shown in FIG. Therefore, there is a problem that the reinforcing effect of the bead 104 is small and an increase in the crush strength of the entire member cannot be expected so much.

In consideration of the above circumstances, the present invention makes the buckling strength on the flat plate side equal to or greater than the buckling strength on the channel member side, and can enhance the buckling strength of the whole vehicle. The purpose is to provide.

[0011]

According to a first aspect of the present invention, there is provided a flange at a widthwise end portion of a long plate material, and these flanges are spot-welded at a predetermined pitch L in the longitudinal direction to form a polygonal closed cross section. In the vehicle strength member formed in,
The one flange is continuously formed on the extension of one end in the width direction of the flat plate portion forming one side of the closed polygonal cross section without passing through a corner, and the other end in the width direction of the flat plate portion is closed by the polygon. A fixed end rigidly connected in the longitudinal direction to adjacent flat plate portions forming the other side of the cross section, and the total length of the length of the flat plate portion forming the one side and the width of the one flange is When the length is longer than each flat plate portion forming the other side of the polygonal closed cross section, the flat portion corresponding to the one side is formed with a reinforcing portion in the entire longitudinal direction, and the position of the reinforcing portion is changed to When the length of the long side is b, it is set within the distance of b from the fixed end and within the distance of 0.47b ² / L from the free end of the flange.

The invention according to claim 2 is the strength member for a vehicle according to claim 1, wherein the reinforcing portion is formed by a bead.

The invention of claim 3 is the strength member for a vehicle according to claim 1, characterized in that the reinforcing portion is formed by increasing the plate thickness.

A fourth aspect of the present invention is the vehicle strength member according to the first aspect, wherein the reinforcing portion is formed by joining separate members.

A fifth aspect of the present invention is the vehicle strength member according to the first aspect, wherein the reinforcing portion is formed by an intermittent bead provided between the spot welding points. To do.

A sixth aspect of the present invention is the vehicle strength member according to any one of the first to fifth aspects, wherein at least two plate members are provided and the flanges are provided at both widthwise ends of each plate member. In the flat plate portion, two or more reinforcing portions are formed at intervals, and the position of one reinforcing portion is determined with the other reinforcing portion side as the fixed end.

The invention according to claim 7 is the strength member for a vehicle according to any one of claims 1 to 5, characterized in that the fixed end is formed of a corner portion of the polygonal cross section.

[0018]

According to the first aspect of the present invention, the buckling strength of the flat plate portion from the reinforcing portion to the fixed end and the buckling of the flat plate portion from the reinforcing portion to the flange free end are provided by limiting the reinforcing portion to a predetermined position. Both the flexural strengths are higher than the buckling strength of the flat plate portion on the next longest side. Therefore, between the pitches of spot welding (between welding points), the flat plate portion corresponding to one side and the flange on the extension thereof is prevented from buckling first than the other portions.

According to the second aspect of the invention, the strength of the reinforcing portion can be adjusted by the shape and width of the bead.

According to the third aspect of the present invention, since the reinforcing portion is formed by partially increasing the plate thickness, the strength of the reinforcing portion can be adjusted by the plate thickness and the width of the plate thickness increasing portion. it can.

According to the fourth aspect of the present invention, since the reinforcing portion is formed by joining the separate members, the strength of the reinforcing portion can be adjusted by the material strength and size of the separate member.

According to the fifth aspect of the invention, since the reinforcing portion is formed by the intermittent beads, it is possible to effectively reinforce only the portion originally required to be reinforced. Further, during crushing, the deformation progresses in a bellows shape, with the spot welding points where the beads are discontinuous as nodes.

According to the invention of claim 6, the position of one of the reinforcing portions is determined with the other reinforcing portion as a fixed end, so that the buckling between the tacks of the flat plate portion precedes the buckling of the other portion. Prevented from happening. In this case, the buckling strength of the flat plate portion can be adjusted by the mutual positional relationship of the reinforcing portions, and it is possible to cope with the case where the size of the flat plate portion is large.

According to the invention of claim 7, when the plate member is formed in a cross section other than a flat plate (for example, L-shaped) and the fixed end is a corner, if the position of the reinforcing portion is set with reference to this fixed end, The buckling strength of the flat plate portion in the range from the corner portion to the free end of the flange can be made greater than or equal to the buckling strength of the portion that is next to be buckled.

[0025]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a first embodiment.

The strength member of this embodiment has a rectangular closed cross-sectional shape by welding the long channel material 101 as the first plate material and the flat plate portion 102 as the second plate material together. Has been formed.

The channel material 101 has a U-shaped cross section with one side open, and has a vertical wall surface 101b of side length b and two horizontal wall surfaces 101a of continuous side length a (b ≧ a) at both ends thereof. . An outwardly bent flange 101c (formed through a corner) is provided at an end of each of the lateral wall surfaces 101a, and the flat plate portion 102 is aligned with the channel material 101 so as to close the opening. The flanges 102c at both ends of the flat plate portion 102 in the width direction (on the extension of one side forming the polygonal closed cross section) and the flange 1 of the channel member 101.
01c is joined by spot welding with a predetermined pitch L. Reference numeral 103 indicates a spot welding point. The side length c of the flat plate portion 102 (the length obtained by adding the widths of the flanges 102c and 102c at both ends to the length of the actual side forming the cross section) is longer than the side length b.

Further, the flat plate portion 10 constituting this strength member
Two beads 105a and 105b, which are reinforcement portions and extend continuously in the axial direction, are provided as reinforcement portions at predetermined intervals on the reinforcement portion 2. Bead 105 of this strength member
A cross section C of a portion including a and 105b has a shape as shown in FIG. The beads 105a and 105b have a width s
Of the same rectangular cross-section, are formed to be convex on the outer surface side, and are both separated from the free end of the flange 102c by d1 and separated from each other by d2.

Next, the operation will be described.

Here, as shown in FIG. 3, (1)-
The three strength members of (3) will be taken as an example to compare and examine them.

In FIG. 3, (1) and (2) are strength members shown as Comparative Examples 1 and 2, and (3) is a strength member corresponding to this embodiment. (1) is an example in which no bead is formed on the flat plate portion 102, (2) is an example in which a bead 104 is formed in the center of the flat plate portion 102 in the width direction (corresponding to the conventional example shown in FIG. 19), and (3) is a flat plate. Two beads 105a on the part 102,
This is an example of forming 105b.

FIG. 4 shows a buckling mode of flat plates having different supporting conditions.

In each case, the two sides in the compression direction are simple support conditions, but the constraint conditions on the two sides of the flat plate are different.
Two sides of (1) are free ends, one side of (2) is a fixed end, the other is a free end, and two sides of (3) are fixed ends.

Here, when applied to the flat plate portion, the free end refers to a case where the end portion of the flat plate portion has at least a part that is not rigidly connected to the adjacent flat plate portion, and the fixed end is the fixed end. , The case where the flat plate portions are connected rigidly in the entire longitudinal direction.

According to the buckling analysis using the finite element method, the buckling strength in each case is about 1: 1.5: 3.2.
Is the ratio of The buckling strength of the beadless flat plate portion 102 shown in (1) of FIG. 3 corresponds to (1) of FIG. Further, in the flat plate portion 102 having the bead 104 at the center shown in (2) of FIG. 3, the end portion on the flange 102c side is a free end between the spot welding points, but is installed at the center of the flat plate portion 102. Since the bead 104 acts as a support side, the buckling strength corresponds to (2) in FIG. Further, the bead 10 is provided in the vicinity of the spot welding flange 102c shown in (3) of FIG.
In the flat plate portion 102 having 5a and 105b, one of the two beads 105a and 105b serves as a fixed end of the other, so that the buckling strength thereof corresponds to (3) in FIG.

According to the research on the crushing strength of the box-shaped cross-section member, the crushing strength of the whole member is proportional to the wall buckling strength to the 0.43th power, so that (1) in FIG.
The ratio of the crushing strengths of the members (2) and (3) on the flat plate portion 102 side is about 1: 1.19: 1.65.

On the other hand, the vertical wall surface (= wall surface with the longest side length) 101b on the side of the channel material 101 having a U-shaped cross section corresponds to a flat plate whose both sides are supported. Therefore, in any case, as shown in (3) of FIG. Has buckling strength. That is, the crushing strength of each member shown in FIG.
It is the sum of the crushing strength of 01 and the crushing strength of the flat plate portion 102.
Using the above crush strength ratio, it is 2: 2.19: 2.6.
5 = 1: 1.10: 1.33.

FIG. 5 shows the result of calculation of axial crushing characteristics by the finite element method using a simple model corresponding to the three types of members shown in FIG. 5 (1)-
The model (3) corresponds to a simplified version of (1) to (3) in FIG. 3, respectively. In (1) and (2) of FIG.
Between the spot welding points 103 joining the channel member 101 and the flat plate portion 102, inter-tack buckling occurs and the mouth is opened, whereas in (3), the mouth opening is reduced. Recognize.

FIG. 6 is a graph showing the crush load and energy absorption amount of each member (1) to (3).
The graph in (a) compares the average crush load,
The ratio of the crush load of each member of (1), (2) and (3) is
It is 1: 1.05: 1.17. The graph of (b) shows the amount of energy absorbed by plastic deformation, and the ratio thereof was 1: 1.09: 1.32, which was a result substantially matching the previously obtained strength ratio.

As described above, the strength member shown in (2) of FIG. 3 (corresponding to the conventional example of FIG. 19) is 1 Although the strength is only increased about 1 time, the strength member (corresponding to this embodiment) shown in (3) of FIG.

The installation positions of the two beads 105a and 105b in this embodiment shown in FIG. 1 can be considered as follows.

As shown in FIG. 2, the two beads 105a and 105b in the present embodiment are provided with the flange 10 respectively.
They are arranged at positions separated from the free ends of 2c and 102c by a distance d1 and a distance d2 from each other. The range sandwiched between the two beads 105a and 105b can be considered as a flat plate having a side length d2 for supporting both sides.
The range from 5a, 105b to the free end of the flange 102c can be considered as a flat plate having a free end with a side length d1 on one side.

Since the buckling strength of the flat plate whose both ends are supported is inversely proportional to the square of the side length, the buckling strength of the flat plate portion (vertical wall surface 101b) having the side length b on the channel material 101 side and the flat plate portion 102 The buckling strength of the flat plate portion having the side length d2 on the side exceeds that of the former if d2 ≦ b.

On the other hand, the buckling strength of a flat plate having a free end is inversely proportional to the square of the length of the free end (in this example, the length between spot welding points) L and inversely proportional to the side length d1. The buckling strength of a flat plate having a free end is given by s1 = k1 / (d1 · L), and the buckling strength of a flat plate sandwiched between two beads 105a and 105b is given by s2 = k2 / d2 ² . To be However, k1 and k2 are coefficients determined by the second moment of area and the like.

According to the ratio of buckling strength in the flat plate model shown in FIG. 3, s2 = 2.133s1, and in the simplest case, if d1 = d2 = L = b is substituted, k1
/K2=0.47 is obtained.

Under a certain compressive load, the condition for the buckling strength of a flat plate having a free end to exceed the buckling strength of a flat plate sandwiched between two beads 105a and 105b is s1 ≧ s2.
And d1 ≦ 0.47d2 ² / L. If the first condition d2 ≦ b is satisfied, since the buckling occurs earlier in the flat plate of side length b than flat sides length d2, is "d1 ≦ 0.47b ^2/1", the flange 102c
The buckling strength of the studs is the vertical wall surface 101 of the channel material 101.
This is a condition for exceeding the buckling strength of b.

As described above, the two beads 105a, 1
The distance d2 of 05b is less than the distance b, and the flange 1
If the beads 105a, 105b are within 0.47b ² / L or less from the free end of 02a, buckling will occur on the vertical wall surface 101b of the channel material 101 before the flat plate portion 102, and the stud spacer It is possible to prevent a decrease in crushing strength due to bending.

The beads 105a and 105b may be formed so as to be convex on the inner surface side of the flat plate portion 102 or may have different shapes. When the reinforcing portion is composed of the beads 105a and 105b, the reinforcing effect can be easily enhanced without inviting an increase in weight. Also, the beads 105a, 105b
The degree of reinforcement can also be easily adjusted by changing the shape and width of the.

Next, another embodiment will be described.

FIG. 7 shows a second embodiment.

In the strength member of this embodiment, the reinforcing portion 106
The a and 106b are formed by partially increasing the plate thickness instead of forming the beads. That is, the flat plate portion 102 having the flanges 102c and 102c at both ends is
As shown in the cross section D in FIG. 8, the entire plate has a thickness t1, but the reinforcing portions 106a and 106b have a thickness t2 (t
2> t1). The positional conditions of the reinforcing portions 106a and 106b are the same as those in the first embodiment.

Two reinforcing portions 106a, 106 having a large plate thickness
The range sandwiched by b can be considered as a flat plate having a side length d2, and is defined by the reinforcing portions 106a and 106b to the flange 102.
The range up to the free ends of c and 102c can be considered as a flat plate having a free end with a side length d1 on one side. Therefore,
It has a buckling strength characteristic similar to that of the first embodiment. Further, since the reinforcing portions 106a and 106b are configured by increasing the plate thickness, the strength of the reinforcing portion can be effectively adjusted by the increasing plate thickness and the width thereof.

FIG. 9 shows a third embodiment.

In the strength member of this embodiment, reinforcing portions 107a and 107b are formed by joining a strip plate (separate member) 107 having a predetermined thickness to the surface of the flat plate portion 102, as shown in section E in FIG. are doing. The reinforcing portions 107a and 107b are
As a result, the plate thickness becomes t2, which is thicker than the plate thickness t1 of other portions. The operation is the same as that of the second embodiment, but this embodiment is different in that the strength of the reinforcing portion can be easily adjusted depending on the dimensions of the strip 107. In addition,
The members to be joined may be other than the strip plate.

FIG. 11 shows a fourth embodiment.

In the strength member of this embodiment, as the reinforcing portion, the intermittent beads 108 are used instead of the continuous beads.
a and 108b are provided. Beads 108a, 108b
Are installed after the length of about L in the collision direction of the member, and are intermittently formed in a portion excluding the position of the spot welding point 103.

In this case as well, the positional conditions of the beads 108a and 108b are the same as those in the first embodiment.
The range sandwiched by a and 108b can be considered as a flat plate having a side length d2, and the range from the beads 108a and 108b to the free end of the flange 102c can be considered as a flat plate having a free end having a side length d1 on one side. . FIG. 12 shows the shape of the cross section F of the strength member of this embodiment.

This strength member also has a buckling strength characteristic similar to that of the first embodiment. In this case, the beads 108a, 108
Although b is discontinuous, it does not cause buckling between tacks at this position because it is a flat plate supported at both ends with the side length of the range e sandwiched by the spot welding points 103. Further, in the present embodiment, the tip end portion L in the collision direction of the member is approximately L
Since the beads 108a and 108b are not installed in the range of the length, the buckling between the tacks is likely to occur at this portion.

Therefore, in the case of the strength member of the present embodiment, at the time of collision, first, the range from the tip end portion to L is crushed by the buckling between the tacks, and thereafter, the spot welding point 103 in which the beads 108a and 108b are discontinuous. With the position of as a node, the bellows-like deformation progresses, and the effect of absorbing collision energy is enhanced.

FIG. 14 shows a fifth embodiment.

In the strength member of this embodiment, an oblique wall surface 101b 'is provided between the vertical wall surface 101b and the horizontal wall surfaces 101a, 101a of the channel material 101, and the channel material 101 is formed.
Are formed in a hexagonal cross section. Here, the vertical wall surface 10
1b is side length b, lateral wall surface 101a is side length a, and diagonal wall surface 10
1b 'is formed to have a side length b', and the relationship of b ≧ b ′ ≧ a is set. The beads 109a and 109b are formed on the flat plate portion 102 under the same conditions as in the first embodiment. FIG. 14 shows the shape of the cross section G of the strength member of this embodiment. d ₁ and d ₂ are respectively d ₁ ≦ 0.47b
^Since 2/1, d ₂ ≦ b, and both the wall surface of side length d _{1 and} the wall surface of side length d ₂ have higher buckling strength than the wall surface 101 b, buckling between tacks does not occur at the flange portion.

FIG. 15 shows a sixth embodiment.

In the strength member of this embodiment, two plate members are lateral wall surfaces 111b and 112b having a side length b, and a side length c (c ≧ b) orthogonal to each other through a corner 115 serving as a fixed end.
The angle members 111 and 112 having an L-shaped cross section having vertical wall surfaces 111a and 112a are used. FIG. 16 shows the shape of the cross section H.

Both angle members 111 and 112 have the same shape except the shapes of beads 110a and 110b which will be described later. Side wall surface 111 of each angle member 111, 112
The flanges 111d are formed at the widthwise ends of the a and 112a by bending the plate material outward by 90 degrees, and the flange 1d is provided at the widthwise ends of the vertical wall surfaces 111b and 112b having the side length c.
11c and 112c are continuously formed without passing through the corners.
Also, on the vertical wall surface 111b of one angle member 111,
A bead 110a that is convex toward the inner surface is formed adjacent to the flange 111c at the end thereof. Further, on the vertical wall surface 112b of the other angle member 112, a bead 110b that is convex toward the outer surface side is formed adjacent to the flange 112c at the end thereof. Each bead 110a, 110
b is continuously extending in the longitudinal direction of the member, and is formed in the same rectangular cross section with the width dimension s.

The strength member of this embodiment is joined to each other with the vertical wall surfaces 111b and 112b of both angle members 111 and 112 facing each other and the horizontal wall surfaces 111a and 112a facing each other. . That is, the flange 111c formed on the vertical wall surface 111b of the one angle member 111 and the horizontal wall surface 112 of the other angle member 112.
The flange 112c formed on the vertical wall surface 112b of the other angle member 112 by being spot-welded at a predetermined pitch with the flange 112d adjacent to a.
And the flange 111d adjacent to the lateral wall surface 111a of the one angle member 111 are aligned with each other and spot-welded at a predetermined pitch, thereby forming a strength member having a rectangular cross section.

The beads 110a and 110b are formed at positions separated from the free ends of the flanges 111c and 112c by d1 and from the corners 15 by d2. Therefore, the beads 110a, 110b on the vertical wall surfaces 111b, 112b are
Then, the range sandwiched by the corners 115, 115 can be considered as a flat plate having both sides fixed with a side length d2. Similarly, from the beads 110a, 110b to the flanges 111c, 112.
The range up to the free end of c can be considered as a flat plate having a free end with a side length d1 on one side.

D1 and d2 are respectively d1 ≦ 0.47b
² / L, d2 ≤ b, and both the flat plate portion having the side length d1 and the flat plate portion having the side length d2 have higher buckling strength than the lateral wall surfaces 111b and 112b. Therefore, the stud spacers on the flanges 111c and 112c are formed. No buckling. Further, in the present embodiment, the bead 110a is formed inward of the member, so that interference with other components is less likely to occur when the bead is mounted on the vehicle.

In the above embodiment, the number of reinforcing portions is 1.
Although the case of using two or two is shown, two or more may be provided depending on the size of the flat plate portion. Further, the polygonal closed cross section may be formed by bending a single plate material into a bag shape in cross section.

[0070]

As described above, according to the first aspect of the present invention, in the strength member for a vehicle having a polygonal closed cross section in which a long plate material is spot-welded, the flat plate portion having the lowest buckling strength, that is, The end part is a flange for spot welding, and the reinforcing part is provided on the flat plate part whose length, which is the sum of the flange and the side, is longer than any other side. Since it is limited based on the distance from the free end of the flange and the distance from the flange free end, it is possible to effectively prevent the flat plate portion from buckling between tacks (buckling between pitches) before other portions, and the entire member. The buckling strength of can be improved.

By increasing the buckling strength of the flat plate portion, it is possible to improve the balance of the buckling strength of the entire plate, so that it is possible to progress the plastic deformation in a stable mode at the time of crushing. The amount of shock absorption at the time of collision can be increased.

In the actual vehicle body structure, the spot welding pitch cannot always be kept constant because of the construction method and the plate assembly. Therefore, when there is a spot with a large spot welding pitch on the rear side of the strength member, Buckling between tacks may have occurred at the part, causing bending and deformation. However, according to the invention of claim 1, the buckling between tacks can be effectively prevented by the presence of the reinforcing portion, so spot welding is possible. It is also possible to obtain the effect of increasing the tolerance for the pitch of.

According to the invention of claim 3, since the reinforcing portion is formed by locally increasing the plate thickness, the reinforcing effect is high.

According to the invention of claim 4, since the reinforcing portion is formed by joining the separate members, the strength can be easily adjusted and the reinforcing effect is high.

According to the fifth aspect of the present invention, the necessary minimum reinforcement can be performed, the crushing can proceed in a stable mode, and the impact energy absorption efficiency can be improved.

According to the invention of claim 6, due to the mutual positional relationship of the reinforcing portions provided in the flat plate portion, it is possible to effectively prevent the inter-tack buckling of the flat plate portion from occurring before the other portions, and the entire member can be effectively prevented. The buckling strength can be improved.

According to the invention of claim 7, the buckling strength of the flat plate portion in the range from the corner portion to the flange free end is set by setting the position of the reinforcing portion with the corner portion as the fixed end. The buckling strength of the easy portion can be made equal to or higher than that of the flat portion, so that the buckling between the tacks of the flat plate portion can be effectively prevented from occurring prior to the other portions, and the buckling strength of the entire member can be improved.

[Brief description of drawings]

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

FIG. 2 is a cross-sectional view of the same strength member.

FIG. 3 is a perspective view showing a difference in structure between a first embodiment of the present invention and a comparative example.

FIG. 4 is a diagram showing a comparison of buckling deformation of each member in FIG.

5 is a diagram showing a calculation result of buckling deformation of each member of FIG.

FIG. 6 is a diagram showing calculation results of buckling load and absorbed energy of each member of FIG.

FIG. 7 is a perspective view of a strength member for a vehicle according to a second embodiment of the present invention.

FIG. 8 is a cross-sectional view of the same strength member.

FIG. 9 is a perspective view of a vehicle strength member according to a third embodiment of the present invention.

FIG. 10 is a cross-sectional view of the same strength member.

FIG. 11 is a perspective view of a vehicle strength member according to a fourth embodiment of the present invention.

FIG. 12 is a transverse sectional view of the same strength member.

FIG. 13 is a perspective view of a vehicle strength member according to a fifth embodiment of the present invention.

FIG. 14 is a cross-sectional view of the same strength member.

FIG. 15 is a perspective view of a strength member according to a sixth embodiment of the present invention.

FIG. 16 is a transverse sectional view of the same strength member.

FIG. 17 is a perspective view showing an example of a conventional strength member for a vehicle.

FIG. 18 is a transverse sectional view of the same strength member.

FIG. 19 is a perspective view showing another example of a conventional vehicle strength member.

FIG. 20 is a cross-sectional view of the same strength member.

21 is a perspective view showing a crush model of the strength member shown in FIG.

22 is a perspective view showing a crush model of the strength member shown in FIG. 19. FIG.

[Explanation of symbols]

101 Channel Material (Plate Material) 101c Flange 102 Flat Plate (Plate Material) 102c Flange 103 Spot Welding Point 105a, 105b Beads (Reinforcement Part) (Fixed End) 106a, 106b Reinforcement Part 107 due to Increase in Plate Thickness 107 Strips (Separate Member) 107a, 107b Reinforcement part (fixed end) 108a, 108b Intermittent bead (reinforcement part) (fixed end) 109a, 109b Bead (reinforcement part) (fixed end) 110a, 110b Bead (reinforcement part) (fixed end) 111, 112 Angle material (Plate) 115 Corner (fixed end) C, D, E, F, G, H Polygonal closed section

Claims (7)

[Claims] 1. A strength member for a vehicle, which has a flange at a widthwise end portion of a long plate material, and is formed into a polygonal closed cross section by spot-welding these flanges at a predetermined pitch L in the longitudinal direction. Of the polygonal closed cross section is formed continuously without extending through one corner in the width direction of the flat plate portion forming one side of the polygonal closed cross section, and the other end in the width direction of the flat plate portion has the polygonal closed cross section. A fixed end rigidly connected in the longitudinal direction to adjacent flat plate portions forming the other side, and the total length of the length of the flat plate portion forming the one side and the width of the one flange is When it is longer than each flat plate part forming the other side of the polygonal closed cross section, a reinforcing part is formed in the flat plate part corresponding to the one side in the longitudinal direction as a whole. When the length of is set to b, within the distance of b from the fixed end, and 0.47B ² from the free end of the flange
A strength member for a vehicle, which is set within a distance of / L. 2. The strength member for a vehicle according to claim 1, wherein the reinforcing portion is formed of a bead. 3. The strength member for a vehicle according to claim 1, wherein the reinforcing portion is formed by increasing a plate thickness. 4. The strength member for a vehicle according to claim 1, wherein the reinforcing portion is formed by joining separate members. 5. The vehicle strength member according to claim 1, wherein the reinforcing portion is formed by intermittent beads provided between the spot welding points. . 6. The strength member for a vehicle according to claim 1, wherein at least two of the plate members are provided with the flanges at both widthwise ends of each plate member, and Two or more reinforcing portions are formed at intervals, and the position of one reinforcing portion is
A strength member for a vehicle, wherein the other reinforcing portion side is defined as the fixed end. 7. The strength member for a vehicle according to claim 1, wherein the fixed end is a corner portion of the polygonal cross section.