JP2006200702A - Shock absorbing member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shock absorbing member for absorbing shock with bending deformation, with a shock absorbing structure having higher energy absorbing efficiency than conventional one. <P>SOLUTION: The shock absorbing member 300 is provided for absorbing shock with bending deformation. For example, a joint 160 between the layers of laminates arranged at sites where the ends of sheet reinforcing fiber materials 150, 151 approximately abut on each other, is shifted from a joint between upper and lower adjacent layers. Thus, different material properties are imparted to the sites to control sequential destruction at the sites. The shock absorbing structure is provided which has higher energy absorbing efficiency than conventional one. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an impact absorbing member, and more particularly, to an impact absorbing member having a high specific energy absorption amount used for a structural member.

  Conventionally, a fiber reinforced material is used in addition to aluminum as a lightweight and high-strength structural member. The fiber reinforced material is a composite material reinforced with fibers, and fiber reinforced rubber (FRR), fiber reinforced metal (FRM), fiber reinforced ceramics (FRC), fiber reinforced plastic (FRP), and the like are known. Of these, FRP, which is most often used as a fiber reinforced material, uses plastic as a matrix (substrate), and it is known that fibers such as carbon and glass are generally used as the reinforcing material. .

  A material using carbon fiber as a reinforcing material for FRP is called carbon fiber reinforced plastic (CFRP). CFRP is located at the core of advanced composite materials, and is known as a lightweight, high-strength, high-modulus material that is indispensable for the aviation and space fields. As the CFRP material, a unidirectional material (UD material) and a cloth material having different structures and properties depending on the orientation of carbon fibers are known. The UD material is a material form in which carbon fibers are arranged in one direction and molded with an epoxy resin or the like. On the other hand, the cloth material is a material form in which fibers such as carbon fibers are woven or knitted and are molded with an epoxy resin or the like. These CFRPs are excellent in heat resistance and corrosion resistance while being light and about 25% of the weight of iron.

  On the other hand, as an example of a structural member, in vehicles such as automobiles, in order to protect passengers, even better impact energy than beam materials used on automobile side parts such as front pillars, center pillars, and rear pillars. Absorption is expected. In addition, in order to further improve fuel consumption, these pillar materials are preferably light, and aluminum materials or aluminum alloy materials are known. There is a demand for an impact-absorbing material that is lighter than these materials and has a good energy absorption rate.

  For example, in a frame installed on the side structure material of an automobile, a single material is extruded or pressed, the cross-sectional shape is closed, the cross-section is increased, the strength and rigidity are increased, and the amount of energy absorbed during a collision is increased. An increase is being made. In general, as a deformation mode at the time of a side collision, if a center pillar is taken as an example, bending deformation by three-point bending, which is bent with an upper side roof rail and a lower side sill as fulcrums, is applied. Therefore, it is desired that the side structure material has a high durability against bending load and a small deflection due to bending.

  Moreover, in the pillar which is a side structure member of a motor vehicle, when an aluminum material or an aluminum alloy material is used, a hollow structure is employed in order to obtain a large moment of inertia of a cross section with the same weight. Such an impact-absorbing member such as aluminum has a property that the load strength decreases rapidly immediately after the load applied by the impact reaches the maximum strength. This means that when the applied load exceeds the yield point, the shock absorbing member is easily deformed with a small load, and therefore once the yield point is exceeded, the deformation amount of the vehicle body is large. That is, when the yield point is exceeded, the load that can be endured is reduced, and a large deformation of the vehicle body is caused by a small load, so that the amount of energy absorption calculated by the product of the load and the displacement is reduced. Therefore, as a shock absorbing member such as a pillar, even if a load near the yield point continues to be applied after the load reaches the maximum strength and exceeds the yield point, the load strength is maintained until a certain displacement is reached. It is desirable to be a thing.

In this regard, Patent Document 1 discloses a member in which an FRP material is integrated adjacently to the tensile surface side of an aluminum hollow shape. This uses a member that is easily plastically deformed on the compression surface side, and uses a high-strength and lightweight member on the tension surface side, which is responsible for shock absorption on the compression surface side and reduces the amount of surface change on the tension surface side. This is a technology that aims to achieve large energy absorption and small deformation.
Japanese Patent Laid-Open No. 06-101732

  However, in the impact absorbing member disclosed in Patent Document 1, the compression side and the side surface thereof are buckled and deformed by the load on the compression side, and the load is concentrated only on the portion where the buckling deformation occurs. This is because in addition to the force that the compression surface is directly pressed by the load, the side surface resists the load from the compression surface, so that a bending load is generated, and this bending load is also concentrated on the buckled deformation part. . If the load is concentrated on the buckled deformation portion, the strength of the shock absorbing member with respect to the load depends on the strength of the buckling deformation portion. Furthermore, in the shock absorbing member disclosed in Patent Document 1, since aluminum and FRP are joined by bolts, with such a structure, stress concentrates on the bolt joints due to deformation due to load. There is a risk of breaking from the joint before exhibiting the advantages unique to this invention. Even if an adhesive is used instead of the bolt, the upper limit of the strength of the entire beam agent is determined by the strength of the adhesive.

  The present invention has been made in view of the problems as described above. By avoiding the concentration of load and deformation in the buckling deformation portion of the shock absorbing member, the shock having a higher energy absorption rate than the conventional one. An object is to provide an absorbent member.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors differed by devising a laminated structure of fiber reinforcement materials in each part in an impact absorbing member that absorbs an impact by bending deformation. The inventors have found that the above problems can be solved by imparting material characteristics and controlling the order of destruction of each part, and have completed the present invention. More specifically, the present invention provides the following impact absorbing member.

  (1) A hollow impact-absorbing member having a longitudinal direction and a short-side direction, which absorbs an impact by bending deformation, and a compression site where a compressive stress is generated by receiving the impact directly, There is a tensile part that is opposed to the compression part and generates a tensile stress, and a pair of side parts that connect both ends of the compression part and the tensile part, and the compression part, the tensile part, and the side part Is a laminated body formed by laminating sheet-like fiber reinforcements, and each layer of the laminated body is arranged in a circumferential shape so as to extend over at least adjacent parts, and the end portions thereof are substantially aligned. An impact-absorbing member comprising a sheet-like fiber reinforcing material having a seam in contact with each other, wherein a position of the seam of a layer and a position of the seam of a layer adjacent to the upper and lower sides thereof are shifted.

According to the invention of (1), the seams at which the ends of the sheet-like reinforcing fibers of the respective layers constituting the laminate are substantially in contact with each other are arranged so as to be shifted from the positions of the seams of the adjacent layers above and below. .
Thus, by providing a seam in each layer and shifting the position of each layer, the material characteristics of each part can be changed and the order of destruction can be controlled. Therefore, at the time of bending deformation, a load drop after reaching the maximum load can be prevented, and high energy absorption efficiency can be achieved.

  (2) The impact absorbing member according to (1), wherein the number of the sheet-like fiber reinforcing materials constituting each layer of the laminate is two or more.

  According to the aspect of (2), since there are two or more sheet-like fiber reinforcements, sheet-like fiber reinforcements in different fiber directions can be arranged in each part. A laminate can be placed.

  (3) The impact absorbing member according to (1) or (2), wherein the displacement of the joint is 10 mm or more.

  According to the aspect of (3), by setting the displacement of the seam position to 10 mm or more, the fracture strength against the tensile load of the laminated body is improved, and a larger load can be endured. Moreover, since the breaking strength with respect to the tensile load is constant at 10 mm or more, it can be considered that the laminate of the sheet-like reinforcing fiber material is integrated in terms of tensile strength.

  (4) The impact-absorbing member according to any one of (1) to (3), wherein the joints of the respective layers of the laminate are arranged at the same site.

  (5) The impact absorbing member according to any one of (1) to (3), wherein the joint of the certain layer and the joint of the adjacent layer are arranged at different portions.

  According to the aspect (4) or (5), since the joints are arranged at the same site or different sites, different material properties can be changed at each site, so that high energy absorption efficiency can be achieved.

  (6) A hollow impact absorbing member having a longitudinal direction and a transverse direction and absorbing a shock by performing a bending deformation, and a compression site where a compressive stress is generated by receiving the shock directly, There is a tensile part that is opposed to the compression part and generates a tensile stress, and a pair of side parts that connect both ends of the compression part and the tensile part, and the compression part, the tensile part, and the side part Is a laminated body formed by laminating sheet-like fiber reinforcements, and each layer of the laminated body is arranged in a circumferential shape so as to extend over at least adjacent parts, and the end portions thereof are adjacent to each other. A shock absorbing member arranged so as to overlap in the vicinity of the part to be performed.

  According to invention of (6), it arrange | positions so that the sheet-like fiber reinforcement of each layer which comprises a laminated body may extend over the site | part which adjoins, and it arrange | positions so that the edge parts may overlap in the vicinity of an adjoining site | part. ing. Thus, by providing a seam in each layer and shifting the position of each layer, the material characteristics of each part can be changed and the order of destruction can be controlled. Therefore, at the time of bending deformation, a load drop after reaching the maximum load can be prevented, and high energy absorption efficiency can be achieved.

  (7) A hollow impact absorbing member having a longitudinal direction and a transverse direction and absorbing a shock by performing a bending deformation, and a compression site where a compressive stress is generated by receiving the shock directly, There is a tensile part that is opposed to the compression part and generates a tensile stress, and a pair of side parts that connect both ends of the compression part and the tensile part, and the compression part, the tensile part, and the side part Is a laminated body formed by laminating sheet-like fiber reinforcements, and some layers of the laminated body are arranged circumferentially so as to extend over at least adjacent sites, and the end portions thereof are Sheet-like fibers that are arranged so as to overlap in the vicinity of adjacent parts, the other layers of the laminate are arranged in a circumferential shape so as to extend over at least the adjacent parts, and end portions of the sheet-like fibers are substantially in contact with each other Made of reinforcing material, Serial seam and the shock absorbing member which is displaced position of the seam of a layer adjacent to and below.

  According to the aspect of (7), further high energy absorption efficiency can be achieved by the synergistic effect of (1) to (5) and (6).

  According to the present invention, by arranging sheet-like fiber reinforced materials having different laminated configurations at each part of the impact absorbing member, the material characteristics of each part can be changed, the order of fracture can be controlled, and bending It is possible to provide a shock absorbing member that prevents a decrease in load after reaching the maximum load at the time of deformation, and has an increased shock energy absorption rate than the conventional one.

  Hereinafter, an example of a preferred embodiment of the present invention will be described with reference to the drawings.

<Overall configuration>
1 and 2 are views showing an example of an embodiment of the shock absorbing member of the present invention. FIG. 1 is a perspective view schematically showing a part of the shock absorbing member, and FIG. 2 is an AA in FIG. It is a sectional view showing an outline of a section. The impact absorbing member in FIG. 1 has a hollow structure, and illustration of the inside is omitted.

  As shown in FIG. 1, this shock absorbing member 300 has a longitudinal direction X and a short direction Y, and a compressive stress is generated by receiving a shock directly. It consists of a pair of side portions 302 and 303 that connect the both ends of the generated tensile portion 304 and the compression portion 301 and the tensile portion 304. As shown in FIG. 2, a laminated body formed by laminating a plurality of sheet-like fiber reinforcements 150 and 151 is disposed in each part. Each layer of the laminate has a seam 160 that is circumferentially arranged so that any one of the sheet-like fiber reinforcements 150 and 151 extends over the adjacent portion, and the end portions substantially abut against each other. The seam 160 is disposed so as to be shifted from the position of the adjacent upper layer or lower layer seam.

<Sheet fiber reinforcement>
The sheet-like fiber reinforcements 150 and 151 can use carbon fibers, glass fibers, aramid fibers, and basalt fibers as the reinforcement fibers. Epoxy resins, polypropylene resins, unsaturated resins are used as the base materials of these fibers. Aluminum such as polyester resin and vinyl ester resin can be used. Specifically, a sheet-like unidirectional UD material in which the fiber directions are aligned in one direction, a cloth material in which fibers are woven, and a prepreg may be laminated on these base materials.

  Here, the UD material is one of the material forms of the FRP material. A sheet-like FRP in which reinforcing fibers are substantially aligned and hardened in one direction is used as a sheet-like UD material, and the sheet-like UD material laminated in the fiber direction is called a one-way UD material. The unidirectional UD material is an FRP material having anisotropy because the tensile strength in the fiber direction is strong. Further, unlike the unidirectional UD material, the fiber direction may be different for each layer to be laminated. When laminating, the sheets may be alternately laminated one by one, or two or more sheet-like UD materials having the same fiber direction may be stacked, and this may be stacked as one set and alternately for each set. Good.

  The cloth material is one of the material forms of the FRP material, and is a sheet-like FRP material oriented in a woven form by weaving fibers as the structure of the reinforcing fiber of the FRP material, or an FRP material in which this sheet-like FRP material is laminated It is. In other words, the cloth material is an FRP material in which a flat surface is formed by knitting one or a plurality of reinforcing fiber sleeves and a matrix such as a resin is used for the flat surface. The knitting method for forming the woven shape may be plain weave or twill weave. Unlike the unidirectional UD material, the cloth material is generally an FRP material that is isotropic in its strength.

  Prepreg means all uncured fiber reinforced materials, including fiber reinforced plastic (FRP), fiber reinforced rubber (FRR), fiber reinforced metal (FRM), fiber reinforced ceramics (FRC), etc. as fiber reinforced materials. Meaning.

  The fiber direction is the fiber direction determined by aligning the carbon fibers in one direction when forming the FRP material by combining the carbon fibers. In addition, an angle in one fiber direction with respect to the surface of the shock absorbing member is determined, and this is called a fiber orientation angle (orientation angle). The fiber orientation angle is an angle determined from the central axis extending in the longitudinal direction X of the shock absorbing member and the fiber direction through the center of gravity of the shock absorbing member.

  The laminated structure of the sheet-like fiber reinforcing material is not particularly limited. In the compression portion 301, the sheet-like fiber reinforcing material whose fiber direction is the longitudinal direction X and the sheet-like fiber whose fiber direction is the short direction Y are mainly used. It is preferable that the reinforcing material is formed by laminating at least one layer. Specifically, a configuration in which CFRP UD materials having fiber orientation angles of 0 degrees and 90 degrees (hereinafter referred to as CFRP UD materials [0/90]) are laminated at least one layer is preferably used. .

  The laminated structure of the side portions 302 and 303 is mainly composed of a sheet-like fiber reinforcement whose fiber direction is the longitudinal direction X, and a sheet-like fiber reinforcement whose fiber direction has a predetermined inclination angle with respect to the short direction Y. It is preferable that at least one layer is laminated. Specifically, a laminate of CFRP UD materials having fiber orientation angles of 45 °, −45 °, and 0 ° (hereinafter referred to as CFRP UD material [45 / −45 / 0]) is at least one layer at a time. A laminated structure is preferably used.

  The laminated structure of the tensile portion 304 is mainly formed by laminating at least one layer of a sheet-like fiber reinforcing material whose fiber direction is the longitudinal direction X and a sheet-like fiber reinforcing material whose fiber direction is the short direction Y. It is preferable. Specifically, a configuration in which CFRP UD materials having fiber orientation angles of 0 degrees and 90 degrees (hereinafter referred to as CFRP UD materials [0/90]) are laminated at least one layer is preferably used. . In addition, it does not specifically limit about the frequency | count of lamination | stacking, What is necessary is just to have at least one layer which has arrange | positioned the above.

  Here, layers in which the fiber direction is laminated at a fiber orientation angle of 0 degrees and a fiber orientation angle of 90 degrees (CFRP UD material [0/0/90/0] s and CFRP UD material [0/90/0/90] s) is used (8ply), and a layer (here, CFRP UD material [45/135/45/135] s) is used so that the fiber orientation angle has a predetermined inclination angle. FIG. 3 shows a table comparing fracture strains in the case of (8 ply). The fracture strain is a fracture strain at the time of a tensile test. As shown in the table of FIG. 3, in the tensile test in the longitudinal direction, the CFRP UD material [45/135/45/135] s is converted into the CFRP unidirectional UD material [0/0/90/0] s. The strain due to tension was 7 times that of the UD material [0/90/0/90] s of CFRP. Here, 8ply is obtained by laminating reinforcing fiber materials composed of prepregs into eight layers. Further, s means that the configuration of each layer is vertically symmetrical.

  From this result, a layer in which the fiber orientation angle is 0 degrees and a fiber orientation angle of 90 degrees is laminated on the compression portion 301, and a layer in which the fiber orientation angles are laminated so as to have a predetermined inclination angle is disposed in the side portions 302 and 303. Thus, when a load due to impact is applied to the shock absorbing member, the end portion which is the buckling deformation portion of the compression portion 301 having a small fracture strain can be broken first, and the buckling deformation portion of the side portion can be broken. Such strain energy can be released in stages.

  Thus, it is preferable to use a sheet-like fiber reinforcing material having a different fiber direction for the laminated structure depending on each part.

<Seam>
FIG. 4 and FIG. 5 show schematic views of seams between end portions of a suitable sheet-like reinforcing fiber material in the impact absorbing member of the present invention. “Seam” in the present invention refers to a portion in which the ends of adjacent sheet-like reinforcing fiber materials in the same layer of the laminate are substantially in contact with each other, and “substantially contact” means that the sheet-like reinforcing fiber material is They may be in contact or separated.

  In FIG. 4, the sheet-like fiber reinforcements 150 and 151 are arranged so as to extend over adjacent portions, and the seams 160 of the respective layers of the laminate are arranged at different portions from the seams of the adjacent upper and lower layers. Yes.

  In FIG. 5, the sheet-like fiber reinforcements 150 and 151 are disposed so as to extend to adjacent portions, and the seams 160 of the respective layers of the laminate are disposed at the same portion. Further, the seam 160 is arranged so as to be shifted from the seam 160 of the adjacent upper and lower layers.

The displacement of the seam position in FIGS. 4 and 5 is preferably 10 mm or more. As an example of this, FIG. 7 shows the result of measuring the tensile load by changing the position difference W of the seam 160, and FIG. 8 shows a schematic diagram of the stacked state. By increasing the positional deviation W to 10 mm, the breaking strength is improved. Moreover, even if the positional deviation W is 10 mm or more, the fracture strength is constant, so that it can be considered that the laminated body of the sheet-like reinforcing fiber materials 150 and 151 is integrated in terms of tensile strength. The “positional shift” in the present invention refers to the distance between a seam of a layer and the seam of the adjacent upper and lower layers. When seams are arranged at the same site, W shown in FIG. When the seams are arranged at different parts, the total length from the seam 160 to the corner of the shock absorbing member 300 is the sum of the seam shift W ₁ of the tension part 304 shown in FIG. made on the length of the sum of the deviation W ₂ of the seam.

  In FIG. 6, the sheet-like fiber reinforcements 150 and 151 are arranged in a circumferential shape so as to extend to adjacent portions. Furthermore, it has the overlapping part 170 in the vicinity of the adjacent part of a site | part, and it arrange | positions so that the sheet-like reinforcing fibers 150 and 151 may overlap. Moreover, it is preferable that the overlap part 170 of a sheet-like fiber reinforcement is 10 mm or more.

  Further, the seams or the overlaps between the end portions may be used alone in FIGS. 4 to 6 or may be used in combination. For example, when the seam shown in FIG. 4 and the overlap shown in FIG. 6 are used in combination, a part of the layers of the laminate may be the seam shown in FIG. 4 and the other layers may be the overlap shown in FIG. In addition, in some layers of the laminate, it can also be used in combination. In this case, the vicinity of the portion where the compression portion and the side portion are adjacent is the seam shown in FIG. 4, and the tensile portion and the compression portion are adjacent. The part to be made can be an overlap shown in FIG.

<Production example>
FIG. 9 is a schematic view of the prepreg placement step of the shock absorbing member according to the present invention. In the shock absorbing member 300 of the present invention, for example, a plurality of prepregs 150 and 151 are wound around each part of the mandrel 200 and laminated. Then, after making it harden | cure by heat processing using an autoclave, the mandrel 200 can be extracted and the impact-absorbing member 300 can be manufactured.

<Application example>
The shock absorbing member 300 obtained in this way can be applied to, for example, the center pillar 410 of the automobile 400 as shown in FIG. FIG. 11 is an enlarged view of the vicinity of A in FIG. 10, and is a center pillar 410 that undergoes bending deformation at the time of a side collision. In FIG. 11, the present invention is applied to the structural member of the side surface portion of the automobile 400. However, the present invention can be applied to any structural member of the automobile 400. 300 may be used.

<Example 1>
All the UD materials used carbon HTA manufactured by Toho Tenax Co., Ltd. for fiber reinforcement, and epoxy resin (# 112) as a matrix. The sheet-like fiber reinforcement uses a CFPR UD material [0/0/90/0] s for the compression part, and uses a CFPR UD material [45/135/0/0] s for the side part, CFPR UD material [0/0/90/0] s was used. The seam of the sheet-like reinforcing fiber material is arranged at the same position as the seam shown in FIG. 2, the first layer is arranged at the compression site and the tensile site, the second layer is arranged at the side site, and alternately arranged at different sites. did. Deviation seam, deviation _{W 1} of the seam in tension sites are 5 mm, for the deviation _{W 2} of the seam in the side portion is 5 mm, was 10 mm. In FIG. 2, although only four layers from the inside are shown, eight layers (8 ply) are laminated, the thickness of the laminate is 1.8 mm, and the shock absorbing member has a cross section of 50 × 50 mm and a longitudinal direction of 600 mm. Met.

<Example 2>
The sheet-like reinforcing fiber material in the lateral portion in Example 1 was produced in the same manner except that the CFPR UD material [45/135/90/90] s was used.

<Example 3>
The sheet-like reinforcing fiber material in the lateral part in Example 1 was produced in the same manner except that the CFPR UD material [45/135/45/135] s was used.

It is a perspective view which shows the outline of a part of impact-absorbing member of this invention. It is sectional drawing which shows the outline of the A-A 'cross section in FIG. It is a table | surface which shows the result of the tensile test of the fiber reinforced material from which laminated structure differs. It is the figure which showed the joint of the edge parts of a sheet-like reinforcement fiber material. It is the figure which showed the other example of the joint of the edge parts of a sheet-like reinforcement fiber material. It is the figure which showed the further another example of the joint of the edge parts of a sheet-like reinforcement fiber material. It is a figure which shows the relationship between the shift | offset | difference of the joint position of a sheet-like reinforcement fiber material, and the fracture strength of a tensile load. It is the schematic which shows the lamination | stacking state for measuring the breaking strength of a tensile load. It is the schematic of the prepreg arrangement | positioning process of the impact-absorbing member of this invention. It is a figure which shows the motor vehicle in which the impact-absorbing member which concerns on this invention is used suitably. It is an enlarged view of A vicinity in FIG.

Explanation of symbols

150, 151 Sheet-like fiber reinforcement (prepreg)
160 Joint 170 Overlapping portion 200 Mandle 300 Impact absorbing member 301 Compression part 302, 303 Side part 304 Tensile part 400 Automotive shock absorbing structure 410 Center pillar W, W ₁ , W ₂ Length of misalignment of seam position

Claims (7)

A hollow impact absorbing member that has a longitudinal direction and a transverse direction and absorbs impact by bending deformation,
A compression site where compressive stress is generated by receiving the impact directly; a tensile site where tensile stress is generated opposite to the compression site; and a pair of side sites connecting both ends of the compression site and the tensile site; Have
A laminated body formed by laminating sheet-like fiber reinforcements is disposed at the compression site, the tensile site, and the side site,
Each layer of the laminated body is arranged in a circumferential shape so as to extend over at least adjacent sites, and is composed of a sheet-like fiber reinforcing material having a seam whose end portions substantially contact each other,
An impact absorbing member in which a position of the seam of a layer and a position of the seam of a layer adjacent above and below the seam are shifted.   The impact-absorbing member according to claim 1, wherein the sheet-like fiber reinforcing material constituting each layer of the laminate is two or more.   The impact absorbing member according to claim 1 or 2, wherein the displacement of the joint is 10 mm or more.   The impact absorbing member according to any one of claims 1 to 3, wherein the joints of the respective layers of the laminate are arranged at the same site.   The impact absorbing member according to any one of claims 1 to 3, wherein the joint of the certain layer and the joint of the adjacent layer are arranged at different portions. A hollow impact absorbing member that has a longitudinal direction and a transverse direction and absorbs impact by bending deformation,
A compression site where compressive stress is generated by receiving the impact directly; a tensile site where tensile stress is generated opposite to the compression site; and a pair of side sites connecting both ends of the compression site and the tensile site; Have
A laminated body formed by laminating sheet-like fiber reinforcements is disposed at the compression site, the tensile site, and the side site,
Each of the layers of the laminated body is arranged in a circumferential shape so as to extend over at least adjacent parts, and the shock absorbing member is arranged so that end portions thereof overlap in the vicinity of the adjacent parts. A hollow impact absorbing member that has a longitudinal direction and a transverse direction and absorbs impact by bending deformation,
A compression site where compressive stress is generated by receiving the impact directly; a tensile site where tensile stress is generated opposite to the compression site; and a pair of side sites connecting both ends of the compression site and the tensile site; Have
A laminated body formed by laminating sheet-like fiber reinforcements is disposed at the compression site, the tensile site, and the side site,
Some of the layers of the laminate are arranged in a circumferential manner so as to extend over at least adjacent sites, and their end portions are arranged so as to overlap in the vicinity of adjacent sites,
The other layers of the laminate are arranged in a circumferential shape so as to extend over at least adjacent portions, and are formed of a sheet-like fiber reinforcing material having a seam in which the end portions substantially come into contact with each other. An impact-absorbing member in which the position of the seam between adjacent layers is shifted.

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