JP2001227573A - Energy absorbing member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To absorb the energy of the predetermined magnitude even when a web is cracked. SOLUTION: An energy absorbing member 1 which is an Al alloy hollow extruded structural angle comprises upper flat plates 11a and 11b and a lower flat plate 12, webs 13 and 14 provided therebetween, and a recess 15 projecting inward of a hollow space. The recess 15 is directly connected to the upper flat plates 11a and 11b, and relatively small and light weight. In the beginning of the collision, no load is applied to the recess 15, but the load is applied to the recess 15 immediately before and after the webs 13 and 14 are cracked, and thus, the energy can be absorbed even after no load is further applied to the webs 13 and 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an energy absorbing member, and more particularly, to an energy absorbing member used as a bumper reinforcing material for an automobile.

[0002]

2. Description of the Related Art In recent years, it has been used for outer panels and structural materials or parts of transport vehicles such as automobiles, ships, and trains, or for structural materials or parts of home electric appliances, and for members of architectural structures such as roofing materials. From the viewpoint of weight reduction, use of an aluminum (Al) alloy is expected.

One of the uses of aluminum alloys is as an energy absorbing member such as a reinforcement (reinforcement) material for automobile bumpers. Some energy absorbing members are formed as hollow hollow members having a rectangular cross section.This type of energy absorbing member is a so-called crushable material, and when energy is given from the outside due to a collision of a car or the like, the energy absorbing member is formed. The impact energy is absorbed by the deformation of the hollow part. This makes it possible to prevent other members from being damaged as much as possible.

With respect to such an energy absorbing member, the amount of energy to be absorbed necessary to prevent other members from being damaged as much as possible is determined depending on the type of the structure in which the energy absorbing member is used and the site of use. come. On the other hand,
If the amount of energy that can be absorbed is too large, it will be over-designed and the weight will be excessive. Therefore, the energy absorbing member is designed so as to be able to absorb the minimum necessary energy, and not to be overdesigned and not excessively heavy.

FIG. 9 shows an example of a state of use of such an energy absorbing member. In FIG. 9, an energy absorbing member 1 which is an extruded hollow profile made of an aluminum alloy and having a rectangular cross section is shown.
00 has an energy absorbing member 100
Is mounted. In this state, when a load is externally applied to the lower flat plate portion facing the upper flat plate portion 102 by collision or the like, each of the webs (sidewalls) 103 facing each other (only one of them is drawn in FIG. 9) , A force is exerted to compress it in the width direction (length a). As a result, the hollow shape is deformed mainly by the deformation of the web 103 around the connection point with the support member 101, and the energy due to the load is absorbed.

The energy absorbing member 100 is designed such that the energy absorbed by the energy absorbing member 100 at the time when the energy absorbing member 100 is crushed has a predetermined value.

[0007]

The energy absorbing member 100 made of Al alloy as described with reference to FIG. 9 is preferably formed with a small thickness in order to reduce the weight. However, the amount of energy absorbed by the energy absorbing member decreases as the plate thickness decreases, provided that the material and the cross-sectional shape are the same. That is, since the reduction in weight and the increase in the amount of absorbed energy are in a reciprocal relationship, it is difficult to satisfy both of them.

As means for increasing the amount of energy absorbed by the energy absorbing member without increasing the plate thickness, for example, a flat plate portion parallel to the web 103 of the energy absorbing member 100 as shown in FIG. It is conceivable to provide a rib directly connected to both in the hollow portion. However, even if such ribs are provided, there is a problem that the weight of the energy absorbing member increases to some extent.

[0009] Therefore, the present invention is relatively fragile high strength material as the material (e.g., steel (σ _{0. 2):} 100kgf
/ Mm ² or more, Al (σ _0.2 ): 30 kgf / mm ² or more) is intended to improve the structure (shape) of the energy absorbing member in order to secure a high energy absorption amount. An object of the present invention is to provide a relatively lightweight energy absorbing member that can absorb a predetermined amount of energy even when a crack occurs.

[0010]

In order to achieve the above object, an energy absorbing member according to claim 1 is an energy absorbing member for absorbing energy due to an external load. And a first deformed portion that forms a hollow structure together with the pair of opposed portions, and a first deformed portion when a load is externally applied to the pair of opposed portions. And a second deformed part that starts deforming later than the part.

According to the energy absorbing member of the first aspect,
When a load is externally applied to the pair of opposing portions, the first deformed portion starts deforming and then the second deformed portion starts deforming. Since a load from the outside can be absorbed by the second deformed portion even after the crack occurs, it is possible to absorb a predetermined amount of energy.

Further, in the energy absorbing member according to the first aspect, a load that deforms the second deformed portion is hardly applied at the beginning of the deformation of the first deformed portion. That is, the second deformed portion is not directly connected to any of the pair of opposing portions, or is not directly connected to both of them even if it is directly connected to any one of the pair of opposing portions. Therefore, claim 1
In the above energy absorbing member, the second deformed portion is generally smaller and lighter than ribs directly connected to both the upper and lower flat plate portions.

The energy absorbing member of claim 1 is
It may have an arbitrary cross-sectional shape, and is not limited to one having a substantially rectangular cross-sectional shape. Further, the facing portions need not necessarily face each other in parallel. In addition, the facing portion and the first deformed portion are not necessarily one each.
It does not need to be constituted by one surface, and may be constituted by a plurality of surfaces (including both flat surfaces and curved surfaces). Also,
The second deformation portion may be provided inside the hollow portion or may be provided outside the hollow portion. Further, the second deformed portion may have any shape as long as it can absorb energy due to the load applied to the opposing portion.

In the first aspect, when a load is externally applied to a pair of opposed portions, the first deformed portion starts deforming and then the second deforming portion starts deforming. As a specific means, for example, the second deformed portion is not directly connected to any one of the pair of opposed portions, or is directly connected to only one of them, and is located between the planes defined by each of the pair of opposed portions. What is necessary is just to provide.

Further, the energy absorbing member according to claim 2 is
In the above-described energy absorbing member, the second deformed portion is provided within a width of the opposed portion.

According to the energy absorbing member of the second aspect,
Since the second deformed portion is provided within the width of the opposed portion, an energy absorbing member having a relatively small cross-sectional area can be formed. If the width of the support member that supports the energy absorbing member cannot be made larger than the width of the energy absorbing member due to design reasons or the like, the second deformed portion is located outside the width of the opposing portion. In this case, energy absorption by the second deformed portion becomes almost impossible. However, according to the second aspect, even in such a case, it is possible to reliably absorb a predetermined amount of energy.
Here, the “width of the opposing portion” means a dimension of the opposing portion in the width direction with respect to a direction perpendicular to the direction in which the load is applied.

Further, the energy absorbing member of claim 3 is
In the above-described energy absorbing member, a plate thickness of the second deformed portion is larger than plate thicknesses of other portions.

According to the energy absorbing member of the third aspect,
Since the plate thickness of the second deformed portion is larger than the plate thickness of the other portions, only the strength of the second deformed portion is reinforced to realize a predetermined amount of energy absorption and reduce the overall weight. It is possible to plan.

Further, the energy absorbing member of claim 4 is
The energy absorbing member as described above is an extruded member made of an aluminum alloy.

According to a fourth aspect of the present invention, since the energy absorbing member is an extruded member made of an aluminum alloy, the weight of the member can be reduced, and the member can be manufactured relatively easily. Become.

The material used in the present invention may be low-carbon steel, carbon steel or high-tense (high-strength) steel.
As the aluminum alloy, 1000 series, 3000 series, 500 series according to AA or JIS standards may be used according to the required characteristics.
Aluminum alloys such as a 0 series, a 6000 series, and a 7000 series are appropriately selected and used. As described above, in the present invention, since the contradiction between increasing the strength of the material and reducing the amount of energy absorption is structurally solved, there is also an advantage that a higher strength material can be used. In this regard, high tensile steel is used to improve the bending rigidity, and 7000 series aluminum alloy sheet according to AA or JIS standards (hereinafter, simply referred to as "7000 series Al alloy sheet") to reduce the weight.
It is preferred that Further, by using these high-strength materials, there is an effect that the thickness of a bumper or the like can be further reduced.

The 7003 aluminum alloy as an example of the 7000 series aluminum alloy is Al-Zn-Mg-C
a u-based alloy, consisting essentially of 5.0 to 6.5 wt% Zn, 0.5 to 1.0 wt% Mg, 0.35 wt% Fe, 0.3 wt% Mn, It contains 0.3% by weight of Si, 0.2% by weight of Cu, 0.2% by weight of Cr, 0.2% by weight of Ti, and the balance Al and inevitable impurities. However, even if the components do not always meet the specifications, the composition of the components can be appropriately changed. That is, it is permissible to change the component range of the above-mentioned elements and appropriately include other elements according to more specific applications and required characteristics.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of an energy absorbing member used as a bumper reinforcing material for a vehicle according to a first embodiment of the present invention. The energy absorbing member 1 of the present embodiment is an extruded member made of a 7000 series Al alloy, and has a hollow structure having a concave cross section. That is, the energy absorbing member 1 includes two upper flat plate portions 11a and 11b on the same plane, a lower flat plate portion 12 (opposed portion) opposed in parallel to the upper flat plate portions 11a and 11b, and upper flat plate portions 11a and 11b.
And a pair of webs (first deformation portions) 13 and 14 sandwiched between the lower plate portion 12 and directly connected to both of them.
A concave portion (second deformed portion) 15 is provided between the two upper flat plate portions 11a and 11b. The webs 13 and 14, both of which are formed flat, are upper flat portions 11 a and 1 a.
1b and the lower plate portion 12 are connected vertically.

The recess 15 includes inner side walls 16 and 17 provided in parallel with the webs 13 and 14, and an inner bottom surface 18 connecting the inner side walls 16 and 17 as a bottom surface of the recess 15. . The concave portion 15 is provided on the upper flat plate portion 11a, 11
b and is directly connected to the upper plate portions 11a and 11b and the lower plate portion 12
And is provided between them.

When the energy absorbing member 1 is used as a bumper reinforcing material for an automobile, for example, as shown in FIG. 3, two support members are provided on the upper flat plate portions 11a and 11b formed as long members. 7, 8 are attached. Note that the support members 7 and 8 may be attached to the lower flat plate portion 12 side. In FIG. 3, the length of the support members 7 and 8 in the width direction (the direction perpendicular to the paper surface of FIG. 3) may be substantially the same as the width of the upper flat plate portions 11a and 11b for design reasons. In such a state, when the energy absorbing member 1 collides with the wall 9 and a load is applied to the upper flat plate portions 11a and 11b and the lower flat plate portion 12 in a direction of crushing the energy absorbing member 1, at the beginning of the collision, Web 13 and 14
Are deformed around the connection point with the support members 16 and 17.

FIG. 2 is a cross-sectional view showing one state of the energy absorbing member 1 at the connection with the supporting members 7 and 8 during the deformation process. In the present embodiment, at the beginning of the collision,
Since no collision load is applied to web 5, web 1
3 and 14 are upper plate portions 11a and 11b and lower plate portion 1
2 are bent outward by the load applied to them. This load causes the webs 13 and 14 to crack in the order shown from bottom to top, as shown in the figure.
Accordingly, the load applied to the webs 13 and 14 starts to decrease. However, as shown in FIG.
Before and after cracks begin to form in the lower plate portion 12 and the concave portion 1
Since the inner bottom surface portion 5 contacts the inner bottom surface portion 5, a collision load is applied to the concave portion 15. Thereafter, the concave portion 15 that has received the load starts to deform.

Therefore, even if the webs 13 and 14 are cracked and the load applied to the webs 13 and 14 is reduced, the load is applied to the recesses 15 and thereafter, so that the energy absorbing member 1 There is no significant change in the load applied to the. Therefore, the web 13, 14
Even if cracks occur in the steel, it is possible to absorb a predetermined energy.

The recesses 15 which start deforming later than the webs 13 and 14 have upper and lower flat plate portions 11a, 11b,
12 is lighter because it is not directly connected to both. Therefore, according to the energy absorbing member 1 of the present embodiment, it is possible to absorb a predetermined amount of energy with a relatively small weight without increasing the plate thickness.

Further, the energy absorbing member 1 of the present embodiment can be formed to have a relatively small cross-sectional area because the concave portion 15 is provided within the width of the upper and lower flat plate portions 11a, 11b and 12. . Further, even when the width of the support members 7 and 8 for supporting the energy absorbing member 1 cannot be made larger than the width of the energy absorbing member 1 due to design reasons or the like, the reliable energy absorption by the recess 15 can be achieved. As a result, a predetermined amount of energy can be reliably absorbed regardless of the width of the support members 7 and 8.

In the present embodiment, it is preferable that the thickness of the inner side walls 16 and 17 of the recess 15 is particularly larger than the thickness of the other portions. It is possible to reduce the overall weight while realizing a predetermined amount of energy absorption by reinforcing only the strengths of 16 and 17.

Further, since the energy absorbing member 1 of the present embodiment is an extruded member made of an aluminum alloy, the weight of the member can be reduced and the member can be manufactured relatively easily. Becomes

Next, a modification of this embodiment will be described with reference to FIG.
This will be described with reference to FIG. The energy absorbing member 1 ′ shown in FIG. 4 has a middle rib 19 connecting the center of the inner bottom surface portion 18 and the center of the lower flat plate portion 12 only in FIG.
The structure is different from that of the energy absorbing member. By adding the middle rib 19 in this manner, the initial load (maximum load) of the energy absorbing member can be increased.

Next, a second embodiment of the present invention will be described. FIG. 5 is a cross-sectional view of an energy absorbing member used as a bumper reinforcing material for an automobile according to a second embodiment of the present invention. The energy absorbing member 2 of the present embodiment is the same as that of the first embodiment except that the webs 21 and 22 (second deformed portions) are formed by a single curved surface slightly curved inward. In FIG. 5, components other than the webs 21 and 22 are denoted by the same reference numerals as those in FIG.

FIG. 6 shows the energy absorbing member 2 at the connection portion with the supporting members 7 and 8 when the energy absorbing member 2 collides with the wall 9 while being supported by the supporting members 7 and 8 similar to FIG. It is sectional drawing which shows one state in the deformation | transformation process. In the present embodiment, since the collision load is not applied to the concave portion 15 at the beginning of the collision, the webs 21 and 22 are mainly bent by the load applied to the upper plate portions 11a and 11b and the lower plate portion 12. The load causes the webs 21 and 22 to crack as shown in the figure, and accordingly, the load applied to the webs 21 and 22 starts to decrease. However, as shown in FIG. 6, before and after the webs 21 and 22 start to crack, the lower flat plate portion 12 is formed.
And the inner bottom surface portion 18 of the concave portion 15 comes into contact with each other.
5, a collision load is applied. Thereafter, the concave portion 15 that has received the load starts to deform.

Accordingly, even if the webs 21 and 22 are cracked and the load applied to the webs 21 and 22 is reduced, the load is applied to the recesses 15 and thereafter. There is no significant change in the load applied to the. Therefore, the webs 21 and 22
Even if cracks occur in the steel, it is possible to absorb a predetermined energy.

The recesses 15 which start deforming later than the webs 21 and 22 have upper and lower flat plate portions 11a, 11b,
12 is lighter because it is not directly connected to both. Therefore, according to the energy absorbing member 2 of the present embodiment, it is possible to absorb a predetermined amount of energy with a relatively small weight.

Further, in the energy absorbing member 2 of the present embodiment, since the original shapes of the webs 21 and 22 are curved inside the hollow, as shown in FIG.
In the process of absorbing the energy by the external load applied to 1a, 11b, 12
Are bent inwardly as a whole. Therefore, even if the deformation progresses and a crack occurs in any part of the webs 21 and 22, the final stage of the deformation, that is, the upper flat plate portion 11a,
The broken portions of the webs 21 and 22 come into contact with the upper flat plate portions 11a and 11b or the lower flat plate portion 12 until the lower web portion 11b and the lower flat plate portion 12 are close enough to substantially contact each other. Therefore, even if the webs 21 and 22 are cracked, the upper plate portions 11a and 11b and the lower plate portion 1
Since a load is applied to the portion cracked from 2, the energy is not absorbed in the portion after the crack occurs. That is, the cracked web 21,
A certain amount of load is also applied to 22 to perform energy absorption.

In the present embodiment, since the webs 21 and 22 are configured to bend inward in the hollow as a whole, the webs 21 and 22 are formed by the upper and lower flat plate portions 11a, 11b and 12
In the process of absorbing the energy from the external load applied to the upper and lower plates 11a, 11b, and 12, it bends without protruding beyond the width thereof. With such a configuration, even if the webs 21 and 22 are cracked, it is possible to absorb energy of a predetermined size or close to it. Here, "Web 21,
22 is bent without protruding beyond the width of the upper and lower flat plate portions 11a, 11b, 12 ".
Is protruded beyond the width of the upper and lower flat plate portions 11a, 11b, and 12, and if the webs 21 and 22 crack at the protruding portions, energy cannot be absorbed by the load at those portions. The “width of the upper and lower flat plate portions 11a, 11b, 12” here means the upper and lower flat plate portions 11a, 11b in a direction perpendicular to the direction in which the load is applied.
b, 12 means the dimension in the width direction.

As described above, the upper and lower flat plate portions 11a, 11a
The webs 21 and 22 are bent without protruding beyond the width of the upper and lower flat plate portions 11a, 11b and 12 (opposing portions) in the process of absorbing the energy due to the external load applied to the b and 12. Specific means for this will be described. Energy absorbing member 1 according to first embodiment
When the cross section is rectangular (except for the concave portion 15) and the four surfaces are orthogonal to each other, the upper and lower flat plate portions 11a, 11b, and 12 to which an external load is applied are directed toward the hollow inside. And the webs 13 and 14 bend toward the outside of the hollow. Therefore, in order for the web to bend without protruding beyond the width of the facing portion, the web must at least have a portion that forms an acute angle with respect to a plane parallel to the facing portion.

Also, a certain surface tends to bend outwardly in the hollow as the radius of curvature at the corners at both ends increases. Therefore, in order for at least a part of the web to be easily bent inside the hollow, it is preferable that the web has a portion having a corner having a relatively small radius of curvature. Further, even if the corners at both ends of a certain surface are reinforced by overlaying or the like, it is easy to bend inside the hollow. Therefore, in order for at least a part of the web to be easily bent inside the hollow, it is preferable that the web has a portion having a corner portion reinforced with a buildup or the like.

That is, in order for the web (intermediate portion) to bend without protruding beyond the width of the facing portion, it is necessary that the web has an acute angle with respect to a plane parallel to the facing portion. The angle range of the “acute angle” varies depending on the magnitude of the radius of curvature and the degree of reinforcement at the overlay. Note that, here, as a suitable condition for configuring the web to bend without protruding beyond the width of the facing portion, the degree of reinforcement in the size of the radius of curvature or the overlay is mentioned, but other suitable conditions are also preferable. If there is a condition, it is preferable to satisfy the condition.

In the present embodiment, the webs 21 and 22
Is configured to bend without protruding beyond the width of the upper and lower flat plate portions 11a, 11b, 12;
The first and the second 22 may be configured so that at least a part thereof is bent inward in the hollow. Because of this configuration, even if the webs 21 and 22 crack, even if the webs 21 and 22 are cracked, the cracked portions are the upper and lower flat plate portions 11a, 11b,
12 is often considered to fit within the width of the upper and lower plates 11a, 11a.
This is because a load is often applied via the webs b and 12, and even if the webs 21 and 22 are cracked, it is possible to absorb energy of a predetermined size or close to it. Here, “at least partly bends into the hollow inside” means that when the webs 21 and 22 are formed of a plurality of parts instead of one curved surface, even if all of the parts do not bend inside the hollow. , A part of the webs 21 and 22 is bent inward in the hollow, so that at least a part of the webs 21 and 22 have upper and lower flat plate portions 11a,
This is because it is conceivable that a load is applied via 11b and 12 to perform energy absorption.

As in the present embodiment, the webs 21 and 22
Is configured to bend without protruding beyond the width of the upper and lower flat plate portions 11a, 11b, and 12, the amount of energy absorption in the concave portion 15 can be reduced by that amount. It is possible to reduce the weight by reducing the thickness.

Next, a third embodiment of the present invention will be described. FIG. 7 is a cross-sectional view of an energy absorbing member used as a bumper reinforcement for a vehicle according to a fifth embodiment of the present invention. The energy absorbing member 5 of the present embodiment is an extruded member made of a 7000 series Al alloy, and has three hollow structures 51 each having a rectangular cross section.
It has a structure in which 52 and 53 are arranged. That is, as shown in FIG. 7, the energy absorbing member 5 is formed by connecting one relatively small hollow structure 52, 53 to each of the left and right sides of a relatively large hollow structure 51.

The hollow structure 51 includes an upper flat plate portion 60b and a lower flat plate portion 12 facing in parallel with the upper flat plate portion 60b, and a pair of webs 54 sandwiched between the upper flat plate portion 60b and the lower flat plate portion 12 and directly connected to both of them. , 55. The webs 54 and 55 both formed in a plane are vertically connected to the upper flat plate portion 60b and the lower flat plate portion 12, respectively. In addition, the webs 54 and 55 have a hollow structure 52,
A web upper part 54a, 55a and a web lower part 54b, 5b
Respectively.

The hollow structures 52 and 53 are provided with an outer upper flat plate portion 60.
a, 60c, outer side wall portions 56, 57, and outer bottom surface portion 5
8, 59 and the web upper parts 54a and 55a. The outer upper flat plate portions 60a and 60c are
0b together with one plane. In the present embodiment, the upper flat plate portion 60b and the lower flat plate portion 12 are a pair of opposing portions, the pair of webs 54 and 55 are first deformed portions, and the outer upper flat plate portions 60a and 60c and the outer side wall portion 5
6, 57 and the outer bottom surfaces 58, 59 are the second deformation parts. That is, in the present embodiment, unlike the above-described embodiment, the second deformed portion is composed of the upper and lower flat plate portions 60b,
12, the upper and lower flat plate portions 60b, 1
It is provided outside a rectangular hollow structure 51 formed by 2 and a pair of webs 54 and 55.

According to this embodiment, it is possible to obtain the same effects as those of the first and second embodiments.
That is, almost no impact load is applied to the outer side wall portions 56 and 57 at the beginning of the collision, and the outer side wall portions 56 and 57 start deforming later than the webs 54 and 55. According to the absorbing member 5, even when the webs 54 and 55 are cracked, a predetermined energy is absorbed.

However, in the present embodiment, the outer side wall 5
The second deformed portions including the upper and lower flat portions 60b,
3 is provided outside the hollow structure 51 formed by the pair of webs 12 and the pair of webs 54 and 55, the width of the support members 7 and 8 shown in FIG.
When the length is smaller than the length b, the load cannot be directly applied to the outer side wall portions 56 and 57. Therefore, the intended amount of energy may not be absorbed.

In this embodiment, the outer side wall portion 56,
57 is not necessarily the web 5 by the outer bottom surfaces 58, 59.
It is not necessary to be connected to the outer bottom portion 5.
It is not necessary to provide 8,59. In addition, the hollow structures 52, 5
3 may be provided in only one of them.

Next, a modification of this embodiment will be described with reference to FIG.
This will be described with reference to FIG. The energy absorbing member 5 'shown in FIG. 8 differs from the energy absorbing member 5 of FIG. 7 only in that it has a middle rib 19' connecting the center of the upper plate portion 60b and the center of the lower plate portion 12. different. By adding the middle rib 19 'in this manner, it is possible to increase the initial load (maximum load) of the energy absorbing member.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes are possible. For example, the first
Any of the second to third embodiments may be combined with the third embodiment, and the cross-sectional shape may be variously changed.

[0053]

As described above, according to the energy absorbing member of the first aspect, when a load is externally applied to the pair of opposing portions, the first deformed portion starts deforming after the first deformed portion starts deforming. Since the deformation of the second deformed portion is started, even if a crack occurs in the first deformed portion, an external load can be absorbed by the second deformed portion. Energy can be absorbed. The energy absorbing member of the first aspect is generally smaller and lighter than a member having a rib directly connected to both the upper and lower flat plate portions.

According to the energy absorbing member of the second aspect, the energy absorbing member having a relatively small cross-sectional area can be formed because the second deformed portion is provided within the width of the facing portion. A predetermined amount of energy can be reliably absorbed.

Further, according to the energy absorbing member of the third aspect, since the thickness of the second deformed portion is larger than the thickness of the other portions, only the strength of the second deformed portion is reinforced to achieve the predetermined value. It is possible to reduce the overall weight while realizing the energy absorption of the size.

According to the energy absorbing member of the fourth aspect, the weight of the member can be reduced.
The member can be manufactured relatively easily.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an energy absorbing member used as a bumper reinforcing material for an automobile according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing one state of the energy absorbing member shown in FIG. 1 in a deformation process.

FIG. 3 is a schematic diagram showing a case where the energy absorbing member shown in FIG. 1 is used as a bumper reinforcing material of an automobile.

FIG. 4 is a cross-sectional view of an energy absorbing member according to a modification of the first embodiment of the present invention.

FIG. 5 is a cross-sectional view of an energy absorbing member used as a bumper reinforcement for a vehicle according to a second embodiment of the present invention.

FIG. 6 is a cross-sectional view showing one state in a deformation process of the energy absorbing member shown in FIG.

FIG. 7 is a cross-sectional view of an energy absorbing member used as a bumper reinforcing material for an automobile according to a third embodiment of the present invention.

FIG. 8 is a cross-sectional view of an energy absorbing member according to a modification of the third embodiment of the present invention.

FIG. 9 is a perspective view showing an example of a use state of the energy absorbing member.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Energy absorption member 11a, 11b Upper plate part 12 Lower plate part 13, 14 Web 15 Depression 16, 17 Inner side wall part 18 Inner bottom part

Claims (4)

[Claims] 1. An energy absorbing member for absorbing energy due to an external load, wherein said energy absorbing member is sandwiched between a pair of opposed portions and said pair of opposed portions and forms a hollow structure with said pair of opposed portions. A first deformed portion, and a second deformed portion that starts deforming later than the first deformed portion when a load is externally applied to the pair of opposed portions. A characteristic energy absorbing member. 2. The energy absorbing member according to claim 1, wherein said second deformed portion is provided within a width of said opposed portion. 3. The energy absorbing member according to claim 1, wherein the thickness of the second deformed portion is larger than the thickness of other portions. 4. The energy absorbing member according to claim 1, which is an extruded member made of an aluminum alloy.