JP2002139086A - Shock absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shock relaxation member which can reduce a maximum axial compression load. SOLUTION: A thin thickness sectional member relaxes a compression impact applied in an axial direction. The thin thickness sectional member comprises a plurality of wall parts and a corner part connecting the plurality of the wall parts which are provided with a linear recessed part promoting axial collapse deformation in the beginning in an inner or outer side of the member, and a location constituting the linear recessed part is characterized by continuing in a peripheral direction in the corner part in this shock relaxation member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shock absorbing member, and more particularly, to a shock absorbing member applied to a frame member of an automobile or the like.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand in the automobile industry for reducing the weight of a vehicle body and improving collision safety. In order to achieve both a reduction in the weight of the vehicle body and an improvement in crash safety, the impact energy at the time of the collision is absorbed by vehicle structural members other than the passenger compartment components, and deformation of the passenger compartment components is suppressed to reduce the occupant Must not be disturbed. Further, in order to ensure the safety of the occupants, it is necessary to protect the main parts of the vehicle such as the engine and the fuel tank.

[0003] By the way, a vehicle is constituted by a frame member, and when an axial impact load is applied to the frame member constituting the vehicle, the frame member undergoes axial crush deformation. Then, when the first axial crushing deformation of the member occurs, a maximum compressive load (hereinafter, referred to as a “maximum axial compressive load”) is generated.

If the rigidity of the members is increased by increasing the wall thickness in order to increase the energy absorption in the event of a collision, the maximum axial compressive load increases in addition to the increase in the vehicle body weight, so that a greater change in acceleration occurs. Will join
The danger to the occupants may increase. Furthermore, deformation of passenger compartment components and vehicle main parts, which are members that are not desired to be deformed, may cause occupant obstacles, damage engine main parts such as fuel tanks, and threaten the safety of occupants. there's a possibility that.

In order to avoid such a situation, a recess called a crushed bead is provided on the frame member. By appropriately arranging the collapse bead on the frame member, the frame member is easily deformed in a bellows shape at the time of a collision, and without increasing the rigidity of the member due to an increase in wall thickness, that is, an increase in vehicle body weight and a maximum axial compression. The impact absorption energy can be increased without increasing the load.

There have been disclosed several methods of arranging a crush bead for controlling deformation of a shock absorbing member such as a frame member upon collision. FIG. 1 is a perspective view schematically showing a conventional method of arranging a crushed bead. FIG. 1A shows a method of arranging a crushed bead on the wall of a quadrangular box-shaped shock absorbing member. , FIG. 1 (b)
Shows a method of arranging a crushed bead at a corner portion of a hat-type shock absorbing member.

In FIG. 1 (a), the shock absorbing member 1 is
A pair of walls 2, 2, 2, 2 and corners 3, 3, 3, 3 are provided. The recesses 4 are provided on the outside of the member.

In FIG. 1B, the shock absorbing member 1 is
Side portions 21, 21 and a bottom portion 22, which are walls, and corner portions 3, 3, are provided. The corner portions 3, 3 are provided with a plurality of pairs of triangular concave portions 5, 5 as crushed beads in the axial direction.

Automobile technology VoL. 47, no. 4,19
93, pp57-61, the method of arranging a crushed bead shown in FIG. 1 (a) is described, and the method shown in FIG. , Respectively.

[0010]

SUMMARY OF THE INVENTION The present inventors have verified the effect of the crushed bead in the form described in the above literature and the above publication by FEM analysis.

As a result, in the method of arranging a linear recess perpendicular to the axial direction of the frame member as shown in FIG. 1A at the center of the side surface of the frame member, the maximum axial compressive load is sufficiently reduced. It turned out to be difficult.

A method of arranging triangular recesses at corners of a frame member as shown in FIG. 1B is a method of arranging the recesses at appropriate intervals in the axial direction of the frame member. Although it is possible to increase the shock absorption energy by promoting the deformation of the frame member in a bellows shape when subjected to an impact load in the direction, there is a possibility that the maximum axial compression load increases and the risk of occupants increases. It has been found. This is presumed to be caused by arranging the triangular concave portion at the corner of the frame member to make the portion polygonal.

The present invention has been made in consideration of the above-described problems of the related art, and has as its object to provide an impact relaxation member capable of reducing a maximum axial compression load. Still another object of the present invention is to provide a shock absorbing member capable of improving shock absorbing energy.

[0014]

Means for Solving the Problems The present inventors have conducted a detailed study on the shape of a crushed bead capable of effectively reducing the maximum axial compressive load of the shock absorbing member using FEM analysis.
As a result, the following findings were obtained.

(A) As described in the above document, the rigidity of the wall is reduced by arranging a linear recess perpendicular to the axial direction of the shock absorbing member at the center of the wall of the shock absorbing member. Even if it does, since the rigidity of the corner portion is higher than the rigidity of the wall surface, the rigidity at the relevant portion as the entire shock absorbing member does not decrease so much. For this reason, although there is an effect of promoting the initial axial crushing deformation, the maximum axial compressive load cannot be sufficiently reduced.

(B) Therefore, instead of disposing the linear concave portion only at the center of the wall of the shock absorbing member, the linear concave portion is provided over the wall portion and the corner portion, whereby the wall portion is provided. It is necessary to reduce not only the rigidity of the corner portion but also the rigidity of the impact reducing member as a whole at the portion. By adopting such a shape, the initial axial crushing deformation at the site can be effectively promoted, and the maximum axial compressive load can be effectively reduced.

In other words, the maximum axial compressive load can be effectively reduced by arranging linear concave portions continuous in the circumferential direction of the shock absorbing member in the wall portion and the corner portion.
Here, the “wall portion” is a portion that forms a substantially uniform surface of the member, and the shape of the surface includes not only a flat surface but also a gentle curved surface. For example, the case where the surface of the member has a gentle circular or elliptical arc shape in the cross section or a case where the surface is undulating gently is also included. And the "corner part"
It is a site of a member connecting the wall portions.

"Axial direction" is a direction to which a compression shock is applied when the shock-absorbing effect of the shock-absorbing member is most effectively exerted, and "circumferential direction" is the direction of the wall and the corner. The direction is not parallel to the axial direction of the portion.

The term "continuous" means substantially continuous, and the term "substantially continuous" means that the lines provided on the plurality of walls and corners as described above. It means that it is continuous to such an extent that the effect of reducing the maximum axial compression load by the concave portion can be effectively exhibited. Therefore, even when the linear concave portions provided on the two adjacent wall portions via one corner portion are displaced in the axial direction at the corner portion, the effect of reducing the maximum axial compressive load is reduced. If the deviation is such that it can be expressed, it is substantially continuous.

The form of the corner portion where the linear concave portions are continuous is preferably smooth and continuous because the acute angle of the corner portion is not preferable in forming the shock absorbing member.

The cross-sectional shape of the “linear recess” may be any shape,
For example, the shape may be an arc, an ellipse, or a triangle.
The position where the linear concave portion is arranged may be either inside the member or outside the member.

(C) Investigate or predict the initial axial crush deformation of the shock absorbing member in advance, and form a linear line inside or outside each wall of the shock absorbing member so as to promote the axial crush deformation. By arranging the concave portion, by continuing the portion constituting the linear concave portion in the circumferential direction at the corner portion,
Further, the maximum axial compression load can be effectively reduced.

Here, "continuously forming the portion forming the linear concave portion in the circumferential direction at the corner portion" means that the first axial portion is formed by the linear concave portion provided inside or outside the member of the plurality of walls. This means that the crushing deformation is made continuous to such an extent that the effect of promoting crushing deformation can be effectively exhibited.

(D) One or more sets of recesses are arranged in the axial direction at the corners of the shock absorbing member, and the linear recesses described in the above (B) or (C) are subjected to the impact. By arranging the cushioning member closer to the impact surface than the concave portion arranged at the corner in the axial direction, the maximum axial compressive load can be reduced and the shock absorption energy can be increased.

Here, the "impact surface side" means the end surface side where the impact relaxation member receives an impact. The present invention has been completed based on the above findings, and the gist thereof is as follows (1):
(2) The shock absorbing member according to the item (3).

(1) A thin-walled member for reducing the impact of compression applied in the axial direction, wherein the thin-walled member has a plurality of wall portions and a corner portion connecting the plurality of wall portions. An impact-reducing member, wherein the wall portion and the corner portion have a circumferentially continuous linear recess inside or outside the member.

(2) A thin-walled member for reducing the impact of compression applied in the axial direction, wherein the thin-walled member has a plurality of walls and a corner for connecting the plurality of walls. The wall portion is provided with a linear concave portion for promoting the initial axial crushing deformation inside or outside the member, and a portion constituting the linear concave portion is circumferentially continuous at the corner portion. Shock absorbing member.

(3) The corner portion is provided with one or two or more sets of concave portions in the axial direction, and the linear concave portion is larger than the concave portion of the corner portion in the axial direction of the shock absorbing member. The shock absorbing member according to the above (1) or (2), which is located on the impact surface side.

Here, the "thin section member" refers to a member having a cross section of an open section or a closed section in a plane perpendicular to the axial direction. Here, the cross-sectional shape of the “open cross section” is, for example, a hat shape, a U shape, a C shape, an L shape, a Z shape, and the like.
For example, a square or a hexagon.

[0030]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 2 (a), (b)
FIG. 2 is a perspective view schematically showing an example of the shape of a hat-type shock absorbing member according to the present invention. 2A and 2B, the same elements as those in FIG. 1 are denoted by the same reference numerals.

The hat-shaped shock-absorbing member 1 shown in FIG. 2A has side walls 21 and 21 and a bottom 22 which are walls.
And corner portions 3 and 3 connecting these, and the side portions 21 and 21 and the bottom portion 22 and the corner portions 3 and 3 are provided.
Is provided with a linear concave portion 4 continuous in the circumferential direction on the outside of the member.

The hat-type shock-absorbing member 1 shown in FIG. 2 (b) includes side walls 21, 21 and a bottom wall 22, which are walls, and corners 3, 3, which connect them. Parts 21, 21 and bottom part 22 and corner part 3,
3 has a linear concave portion 4 which is continuous in the circumferential direction inside the member.

FIGS. 3A and 3B are perspective views schematically showing examples of the shape of a quadrangular box-shaped shock absorbing member according to the present invention. 3A and 3B, the same elements as those in FIG. 1 are denoted by the same reference numerals.

A quadrilateral box-shaped shock absorbing member 1 shown in FIG. 3 (a) includes walls 2, 2, 2, 2 and corners 3, 3, 3, 3 for connecting the walls. Parts 2, 2,
2, 2 and the corner portions 3, 3, 3, 3 are provided with linear concave portions 4 continuous in the circumferential direction on the outside of the member.

A quadrilateral box-shaped shock absorbing member 1 shown in FIG. 3 (b) includes walls 2, 2, 2, 2 and corners 3, 3, 3, 3 for connecting the walls. Parts 2, 2,
2, 2 and the corner portions 3, 3, 3, 3 are provided with linear concave portions 4 which are continuous in the circumferential direction inside the member.

The shock absorbing member according to the present invention shown in FIGS. 2 (a) and 3 (a) has a linear concave portion extending over the wall portion and the corner portion on the outside of the member. The rigidity at the site as a whole member is reduced, the initial axial crushing deformation at the site can be effectively promoted, and the maximum axial compressive load can be effectively reduced.

The shock absorbing member according to the present invention shown in FIGS. 2 (b) and 3 (b) has a linear convex portion continuous over the wall portion and the corner portion inside the member. ,
The rigidity of the shock absorbing member as a whole at the site is reduced, and the first axial crushing deformation at the site can be effectively promoted, and the impact according to the present invention shown in FIGS. 2 (a) and 3 (a) can be achieved. The maximum axial compression load can be effectively reduced as in the case of the relaxation member.

FIG. 4 is a perspective view schematically showing another example of the shape of the shock absorbing member according to the present invention. FIG. 4 (a) shows a hat-shaped shock absorbing member, and FIG. The quadrilateral box-shaped shock absorbing members are shown respectively.

The hat-type shock-absorbing member 1 shown in FIG. 4A has side walls 21 and 21 and a bottom 22 which are walls.
And a corner portion 3 for connecting them, and the side portions 21, 21 have linear recesses 4, 4 on the outside of the member, and a bottom portion 2.
2 is provided with a linear concave portion 4 inside the member, respectively, a portion constituting the linear concave portion 4 and 4 arranged outside the member and a portion constituting the linear concave portion 4 arranged inside the member are: At the corners 3, 3, it is continuous in the circumferential direction.

The hat-shaped shock-absorbing member having a general cross-sectional shape exhibits an axial crush deformation in which the side portion enters the inside of the hat cross-section and the bottom portion protrudes outside the hat cross-section in the first axial crush deformation.

The hat-shaped shock absorbing member shown in FIG. 4 (a) has a linear concave portion on the side surface, a linear concave portion on the bottom surface, and a linear concave portion on the bottom surface. Since the constituent parts are continuous in the circumferential direction at the corners, the axial crushing deformation is promoted, and the maximum axial compressive load can be effectively reduced.

The shock absorbing member 1 in the form of a quadrilateral box shown in FIG. 4 (b) has walls 2, 2, 2, 2 and corners 3, 3, 3, 3 for connecting the walls. One set of walls 2 and 2 has linear recesses 4 and 4 on the outside of the member, and the other set of walls 2 and 2 has linear recesses 4 and 4 on the inside of the member, and is disposed outside the member. The portions forming the linear recesses 4, 4 and the portions forming the linear recesses 4, 4 arranged inside the member are continuous in the corner portions 3, 3, 3, 3 in the circumferential direction.

The quadrilateral box-shaped shock-absorbing member has an axial crushing deformation in which the first set of opposing walls enters the inside of the box cross section and the other set of walls protrudes outside the box cross section in the first axial crushing deformation. Take the form.

The quadrangular box-shaped shock-absorbing member shown in FIG. 4B has a pair of opposing walls having a linear recess outside the member and another pair of walls having a linear recess. Since the portions provided on the inner side and constituting the linear concave portions are respectively continuous in the circumferential direction at the corner portion, the axial crush deformation can be promoted, and the maximum axial compressive load can be effectively reduced.

As described above, the first axial crush deformation of the shock absorbing member is investigated or predicted in advance, and the linear concave portion is formed on the outer side of each wall of the shock absorbing member or the member so as to promote the axial crush deformation. The maximum axial compression load can be effectively reduced by arranging these components inside in the circumferential direction at the corners.

Note that even in the case of a hat-type shock absorbing member, the initial axial crushing deformation may differ from that described above depending on the cross-sectional shape. In the case of the first axial crushing deformation mode, a linear concave portion is provided on the side surface on the inside of the member, and a linear concave portion is provided on the bottom portion on the outside of the member. What is necessary is just to make each part comprised continuously in a circumferential direction in a corner part.

Also, in the case of a box-shaped shock absorbing member having a complicated cross-sectional shape, a linear concave portion is formed inside or outside the member by investigating or predicting the first axial crush deformation. In this case, it is sufficient to determine which of them is to be arranged.

FIG. 5 is a perspective view schematically showing another example of the shape of the hat-type shock absorbing member according to the present invention. 5, the same elements as those in FIG. 1 are denoted by the same reference numerals.

The hat-type shock absorbing member 1 shown in FIG. 5A is provided with a plurality of sets of recesses 5, 5 in the axial direction in the corner portions 3 of the hat-shaped shock absorbing member shown in FIG. , ...,
5 (however, only two sets of recesses are shown in the figure), and a plurality of sets of recesses 5, 5,... , 5 on the impact surface side.

The hat-type shock absorbing member 1 shown in FIG. 5B has a plurality of sets of recesses 5, 5,... In the corner portions 3 of the hat-type shock absorbing member shown in FIG. 5 is provided in the axial direction (however, only two sets of recesses are shown in the figure), and a plurality of sets of recesses 5, 5,... Are arranged closer to the impact surface than 5.

FIGS. 6A and 6B are perspective views schematically showing another example of the shape of the quadrangular box-shaped shock absorbing member according to the present invention. 6A and 6B, FIG.
The same elements as those described above are denoted by the same reference numerals.

The hat-type shock-absorbing member 1 shown in FIG. 6A has a plurality of sets of recesses 5 in the corners 3, 3, 3, 3 of the hat-type shock-absorbing member shown in FIG. 5, ...,
5 are provided in the axial direction (however, only two sets of recesses are shown in the figure), and a plurality of sets of recesses 5, 5,.・ ・
・ It is located closer to the impact surface than 5.

The hat-type shock absorbing member 1 shown in FIG. 6B has a plurality of sets of recesses 5 in the corners 3, 3, 3, 3 of the hat-type shock absorbing member shown in FIG. 5, ...,
5 are provided in the axial direction (however, only two sets of recesses are shown in the figure), and a plurality of sets of recesses 5, 5,.・ ・
・ It is located closer to the impact surface than 5.

FIGS. 7A and 7B are perspective views schematically showing still another example of the shape of the shock absorbing member according to the present invention, and FIG. 7A is a hat-shaped shock absorbing member. And FIG.
(B) shows a quadrilateral box-shaped shock absorbing member, respectively.

The hat-type shock absorbing member 1 shown in FIG. 7A has a plurality of sets of recesses 5, 5,... In the corner portions 3 of the hat-shaped shock absorbing member shown in FIG. .5 are provided in the axial direction (however, only two sets of recesses are shown in the figure), and linear recesses are disposed outside the members that are formed by circumferentially continuous portions in the corners. 4, 4 and the linear concave portion 4 arranged inside the member are arranged closer to the impact surface than the plural sets of concave portions 5, 5,.

The quadrangular box-shaped shock absorbing member 1 shown in FIG. 7 (b) has a plurality of sets in the corner portions 3, 3, 3, 3 of the quadrangular box-shaped shock absorbing member shown in FIG. 4 (b). , 5 are provided in the axial direction (however, only two sets of concave portions are shown in the figure), and a member constituted by a portion continuous in the circumferential direction in the corner portion A plurality of sets of recesses 5, 5,.
... Arranged closer to the impact surface than 5.

The shock absorbing member according to the present invention shown in FIGS. 5 to 7 has the same linear shape as the shock absorbing member shown in FIGS. By arranging it inside the member, or by arranging a linear recess formed by a portion continuous in the circumferential direction at the corner portion outside or inside the member, the first axial crushing deformation is effectively promoted, The maximum axial compression load can be effectively reduced. Further, by providing a plurality of sets of concave portions in the corner portion in the axial direction, it is possible to promote deformation in a bellows shape after the initial axial crushing deformation, thereby increasing the shock absorption energy.

That is, it is possible to reduce the maximum axial compression load and increase the shock absorption energy. Here, a circumferentially continuous linear concave portion disposed on the outer side or the inner side of the member, or a linear concave portion disposed on the outer side or the inner side of the member, which is constituted by a circumferentially continuous portion in the corner portion, The arrangement on the impact surface side with respect to the plurality of sets of recesses provided in the corner portion reduces the maximum axial compressive load by crushing sequentially from the collision surface side, and
This is for suppressing the reduction of the axial compression load and improving the impact absorption energy.

In the description with reference to FIGS. 1 to 7, the term “impact surface side” refers to the side on which the end face of the member is shown in FIGS. 1 to 7. FIG. 8 is an explanatory diagram illustrating an example of a cross-sectional shape of a linear concave portion provided in a wall portion and a corner portion of the shock absorbing member. In the figure, the same elements as those in FIG. 1 are denoted by the same reference numerals.

When the sectional shape of the linear concave portion 4 is expressed by using a concave portion width: B and a concave portion depth: H, the concave portion width: B is 5t ≦ B.
It is preferable that ≦ 40t. Here, t represents the thickness of the shock absorbing member. If B is less than 5t, the effect of reducing the maximum axial compression load may be reduced. B to 40
If it exceeds t, the maximum axial compressive force may be reduced more than necessary, and it may be extremely weak against impact from a direction perpendicular to the axis.

The depth H of the recess is 0.9t ≦ H ≦ 3.
0t is preferable. If H is less than 0.9 t, the effect of reducing the maximum axial compression load may be reduced. If H is more than 30t, it becomes extremely weak against an impact from a direction perpendicular to the axis, and the thickness of the part becomes extremely thin due to elongation of the part at the time of molding, which may cause breakage.

When the cross-sectional shape of the concave portion is an arc shape as shown in FIG. 8, the radius of curvature R1 of the arc may be appropriately determined according to B and H, and the radius of curvature R2 at the end of the arc may be large. The thickness is not particularly defined since it may be determined in consideration of the ease of molding.

In this embodiment, an example has been described in which one set of linear concave portions provided on the wall portion and the corner portion is provided on the impact surface side, but the present invention is not limited to this. That is, the number of linear concave portions provided in the wall portion and the corner portion and the number of concave portions provided in the corner portion may be appropriately determined according to the member length. From the viewpoint of suppressing an excessive decrease in the strength of the shock absorbing member, one set of linear concave portions provided on the wall portion and the corner portion is provided on the impact surface side. It is preferable to determine the value appropriately.

[0064]

EXAMPLE In order to verify the effect of the present invention, a member having a shape shown in FIG. 4A (Example A of the present invention) and a member having a shape shown in FIG. (Example B of the present invention) As a conventional shock absorbing member, a member having a shape as shown in FIG. 1B (conventional example C, conventional example D) and a hat-shaped member having no crushed bead (conventional example E)
The maximum axial compression load and the impact absorption energy were determined using FEM analysis. Here, the invention examples A and B and the conventional example C,
D and E were set so that the member thickness was equal and a thin steel plate was joined to the opening of the hat-shaped member. The rigid wall having a surface parallel to the impact surface and larger than the impact surface is set to collide with the impact surface of the hat-shaped member in the axial direction so that a uniform impact axis compression force is applied. Here, the end of the hat-shaped member on the side opposite to the impact surface is fixed, and the collision speed against the rigid wall is 5
It was set to 5 km / h. Table 1 shows the specifications of the test specimen.

[0065]

[Table 1] Tables 2 and 3 show Examples A and B of the present invention and Examples C and D of the prior art.
, The maximum axial compression load ratio and the shock absorption energy ratio with respect to Conventional Example E are shown. Here, the maximum axial compressive load ratio with respect to the conventional example E is the present invention examples A and B and the conventional examples C and D,
The maximum axial compressive load for E is divided by the maximum axial compressive load for Conventional Example E. The ratio of the energy absorbed to Conventional Example E refers to Examples A and B of the present invention and Conventional Examples C and
The shock absorption energy for D and E is divided by the shock absorption energy for Conventional Example E.

[0066]

[Table 2]

[0067]

[Table 3] Table 2 shows the results when one set of crushed beads was placed, and Table 3 shows the results when three sets of crushed beads were placed.

As shown in Table 2, Example A of the present invention had a greatly reduced maximum axial compressive load and improved impact absorption energy as compared with Conventional Example E. Conventional example C is
The impact absorption energy was the same as that of Inventive Example A, but the maximum axial compressive load was larger than that of Conventional Example E.

As shown in Table 3, in the example B of the present invention, the maximum axial compressive load was effectively reduced as compared with the conventional example E, and the impact absorption energy was greatly improved. In Conventional Example D, the shock absorption energy became a value close to that of Invention Example B, but the maximum axial compressive load was significantly larger than in Conventional Example E.

[0070]

According to the present invention, since the maximum axial compressive load of the shock absorbing member can be reduced, it is suitable as an automobile frame member or the like. According to another aspect of the present invention, the impact absorption energy can be further improved.

[Brief description of the drawings]

FIG. 1 is a perspective view schematically showing a conventional typical collapse bead arrangement method.

FIG. 2 is a perspective view schematically showing an example of the shape of a hat-type shock absorbing member according to the present invention.

FIG. 3 is a perspective view schematically showing a shape example of a quadrangular box-shaped shock absorbing member according to the present invention.

FIG. 4 is a perspective view schematically showing another example of the shape of the shock absorbing member according to the present invention.

FIG. 5 is a perspective view schematically showing another example of the shape of the hat-type shock absorbing member according to the present invention.

FIG. 6 is a perspective view schematically showing another example of the shape of the quadrangular box-shaped shock absorbing member according to the present invention.

FIG. 7 is a perspective view schematically showing still another example of the shape of the shock absorbing member according to the present invention.

FIG. 8 is an explanatory diagram showing an example of a cross-sectional shape of a linear concave portion provided in a wall portion and a corner portion of the impact relaxation member.

[Explanation of symbols]

1: Impact relaxation member 2: Wall portion 21: Side portion (wall portion) 22: Bottom portion (wall portion) 3: Corner portion 4: Linear concave portion (crushed bead) 5: concave portion (crushed bead)

Claims (3)

[Claims] 1. A thin-walled member for reducing the impact of compression applied in the axial direction, the thin-walled member comprising a plurality of walls and a corner connecting the plurality of walls, wherein the plurality of walls The shock absorbing member, wherein the portion and the corner portion have a linear concave portion continuous in the circumferential direction inside or outside the member. 2. A thin-walled member for reducing the impact of compression applied in the axial direction, the thin-walled member comprising a plurality of walls and a corner connecting the plurality of walls, wherein the plurality of walls are provided. The part is provided with a linear concave portion that promotes initial axial crushing deformation inside or outside the member, and a portion constituting the linear concave portion is circumferentially continuous at the corner portion. Relaxing member. 3. The corner portion has one or two or more sets of recesses in the axial direction, and the linear recesses have a greater impact than the recesses of the corners in the axial direction of the shock absorbing member. The impact relaxation member according to claim 1, wherein the impact relaxation member is located on a surface side.