JP4760782B2 - Energy absorbing member - Google Patents

Description

  The present invention relates to an energy absorbing member that absorbs energy by plastic deformation when a compressive load is input.

For example, Patent Document 1 discloses an energy absorbing member that constitutes a part of a vehicle frame and is used to absorb an impact load at the time of a collision. The energy absorbing member includes a cylindrical main body and a concavo-convex portion formed at an intermediate position in the cylinder axis direction on the outer peripheral surface of the main body. In this energy absorbing member, when a compressive load in the cylinder axis direction is input to the main body, the main body is bent and deformed relatively large in the cylinder axis direction starting from the uneven portion, thereby absorbing energy. I am doing so.
JP 2005-29064 A

  However, since the conventional energy absorbing member has a relatively large bending deformation of the main body, a portion other than the deformed portion, that is, a large part of the main body hardly participates in energy absorption. For this reason, there exists a problem that the amount of energy absorption (weight efficiency of energy absorption) with respect to a member weight is comparatively low.

  Due to such low weight efficiency, when the energy absorbing member is used to constitute a part of the vehicle frame, for example, the fuel consumption is deteriorated as the vehicle weight increases.

  This invention is made | formed in view of this point, The place made into the objective is to provide the energy absorption member with high weight efficiency of energy absorption.

  According to one aspect of the present invention, the energy absorbing member is a cylinder including at least two relatively rigid and highly rigid portions, and a portion other than the highly rigid portion and a relatively rigid and low rigid portion. The high-rigidity portion is disposed on the peripheral wall of the main body in an oblique direction inclined with respect to the direction of the cylinder axis, and the low-rigidity portion is a high-rigidity opposed to the oblique direction. When the compressive load in the cylinder axis direction is input to the main body, the high-rigidity parts opposed to the oblique direction move so as to approach each other in the cylinder axis direction. Accordingly, the low-rigidity portion located between the high-rigidity portions undergoes shear deformation.

  According to this configuration, when a compressive load in the cylinder axis direction is input to the main body, the main body deforms so as to contract in the cylinder axis direction. As a result, in this energy absorbing member, the high-rigidity portions opposed to each other in the oblique direction move in a direction approaching each other in the cylinder axis direction. It becomes like this. In this shear deformation, a large number of deformation wrinkles (wrinkles due to bending) extending in a direction inclined with respect to the cylinder axis are formed at short intervals in the relative direction of the high-rigidity portion. Therefore, deformation occurs over a wide range of the energy absorbing member, and since the amount of energy absorption increases due to the complicated deformation, the weight efficiency of energy absorption is greatly improved.

  The energy absorbing member is configured such that when the compressive load in the cylinder axis direction is input to the main body, the low-rigidity portion undergoes shear deformation and the entire main body deforms in a bellows shape in the cylinder axis direction. Also good.

  In other words, when a compressive load in the cylinder axis direction is input to the main body, the high-rigidity portions that are opposed to each other in the oblique direction move to positions that are substantially adjacent to each other in the circumferential direction, and shear deformation of the low-rigidity portions is almost completed. After that, the main body may be further deformed in a bellows shape in the cylinder axis direction. By doing so, the energy absorption weight efficiency is further improved as the deformation of the energy absorbing member becomes more complicated and the amount of energy absorption increases.

  The main body has a polygonal cross section formed by alternately arranging a ridge line portion and a flat surface portion in the circumferential direction on the peripheral wall, and the ridge line portion is adjacent to the cylinder axis direction in the two regions. The positions may be shifted from each other in the circumferential direction, the high-rigidity portion may be configured by the ridge line portion, and the low-rigidity portion may be configured by the planar portion.

  The high-rigidity part and the low-rigidity part may have different wall thicknesses. Further, the high-rigidity part and the low-rigidity part may be made of different materials.

  The high-rigidity portion may be formed by locally performing heat treatment at a predetermined position on the side wall of the main body.

  The body having a polygonal cross section may be formed by inserting a molding die having a predetermined shape into the cylindrical member having openings at both ends in the direction of the cylinder axis from each opening to bend and deform the peripheral wall of the cylindrical member. Good.

  The main body composed of a high-rigidity part and a low-rigidity part having different wall thicknesses may be formed by a tailored blank method or a hydroform method.

  The main body composed of a high-rigidity part and a low-rigidity part having different materials may be molded by a welding method or a friction stir welding method.

  A plurality of main bodies including the high-rigidity part and the low-rigidity part may be provided, and the plurality of main bodies may be stacked coaxially with each other.

  By doing so, the amount of energy that can be absorbed is further increased, and the weight efficiency of energy absorption is further improved.

  The main body is arranged so that the cylinder axis direction thereof coincides with the vehicle front-rear direction and constitutes a part of the front frame of the vehicle, and the low-rigidity part shear-deforms the collision load input to the vehicle. It is good also as absorbing by doing.

  As described above, since this energy absorbing member has a high energy absorption weight efficiency, when used as a vehicle frame member, there is an advantage that the vehicle weight is reduced.

  As described above, according to the present invention, when a compressive load in the cylinder axis direction is input to the main body composed of the high rigidity portion and the low rigidity portion, the low rigidity portion located between the high rigidity portions is sheared. By deforming, complicated deformation occurs over a wide range of the energy absorbing member, and the weight efficiency of energy absorption can be greatly improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the following description of the preferred embodiment is merely illustrative in nature, and is not intended to limit the present invention, its application, or its use.

(Embodiment 1)
FIG. 2 shows the energy absorbing member 10 according to the first embodiment of the present invention. As shown in FIG. 1, the energy absorbing member 10 is, for example, in the vehicle front-rear direction at the vehicle width direction both side positions at the front of the vehicle. Are used as a crush can 92 interposed between the front end portion of the front side frame 91 and the front end of the front side frame 91 and the bumper reinforcement.

  The energy absorbing member 10 includes a cylindrical main body 11, and the peripheral wall of the main body 11 includes a relatively rigid high rigidity portion and a relatively low rigidity low rigidity portion. . Specifically, as shown in FIGS. 2 and 3, the main body 11 has three ridge line portions 12 each corresponding to a high-rigidity portion and three plane portions 13 each corresponding to a low-rigidity portion alternately arranged in the circumferential direction. The ridgeline in the region of one side in the cylinder axis direction (for example, the region on the left side in FIG. 2) and the region on the other side (the region on the right side in FIG. 2) having a triangular cross section The positions of the portions 12 are arranged so as to be shifted from each other in the circumferential direction. In other words, the main body 11 is configured to abut two hollow triangular prisms in the cylindrical axis direction with their ridge lines being shifted from each other.

  Here, in the main body 11, the ridge line portion 12 and the flat surface portion 13 that are opposed to each other in the cylinder axis direction are smoothly joined, so that in the main body 11, the ridge line portion 12 is in the direction of the cylinder axis. In addition to being arranged relative to the inclined oblique direction, a joint portion 14 as a part of the flat surface portion corresponding to the low-rigidity portion is arranged between the ridge line portions 12 opposed to the oblique direction. ing.

  The material of the main body 11 can be appropriately selected from various materials used as members constituting a vehicle frame, such as steel and aluminum.

  The energy absorbing member 10 having the above-described configuration can be manufactured by appropriately adopting various known molding methods. As an example, as shown in FIG. 4, a cylindrical member 82 that becomes the main body 11 of the energy absorbing member 10 can be manufactured by bending using a molding die 81 having a predetermined shape.

  That is, a cylindrical member 82 having both ends opened in advance in a predetermined molding direction is prepared. A pair of forming dies 81 having a triangular prism shape on the base end side and a triangular pyramid shape on the tip end side are prepared.

  Then, the pair of molding dies 81 are arranged relative to each other with their base end side equilateral triangles shifted from each other by 60 °, and each of the molding dies 81 is placed on each of the cylindrical members 82. Insert from the opening inward in the tube axis direction. By doing so, at the both ends in the cylinder axis direction, the molding die 81 is bent so that the peripheral wall of the cylindrical member 82 has a triangular cross section, and at the center in the cylinder axis direction, the ridge line The portion 12 and the flat portion 13 are smoothly connected. Then, by removing the respective molding dies 81 from the member 82, the ridge line portion 12 is disposed relative to the oblique direction, and the joint portion 14 is disposed between the ridge line portions 12 opposed to the oblique direction. Further, the energy absorbing member 10 is molded.

  Next, how the energy absorbing member 10 is deformed when a compressive load is input to the energy absorbing member 10 will be described with reference to FIG. In the following description, the right region in FIG. 5 of the energy absorbing member 10 is referred to as a right region, and the left region is referred to as a left region.

  It is assumed that a compressive load (impact load) in the cylinder axis direction is input from the right side to the right end of the main body 11 in FIG. 5 (see the black arrow in FIG. 5). The compressive load transmits the main body 11 in the cylinder axis direction (see P1).

  Due to the compressive load, the main body 11 is deformed so as to contract in the cylinder axis direction. At this time, each ridge line portion 12 in the right region relatively moves so as to bite into the plane portion 13 in the left region, and thereby, the joint portion 14 positioned between the ridge line portions 12 opposed to each other in an oblique direction, Shear deformation occurs (see P2). Here, due to the shear deformation, a large number of deformation wrinkles extending in a direction inclined with respect to the cylinder axis are generated in the joint portion 14.

  Then, when each ridge line portion 12 in the right region moves to a position adjacent to the ridge line portion 12 in the left region in the circumferential direction and shear deformation is substantially completed, the energy absorbing member is omitted although illustration is omitted. 10 has a substantially hexagonal cylindrical cross section. Thereafter, the substantially hexagonal cylindrical main body 11 is deformed into a bellows shape by a compressive load in the cylinder axis direction (see P3).

  Thus, in this energy absorbing member 10, when the compressive load in the cylinder axis direction is input, the joint portion 14 undergoes shear deformation. Due to this shear deformation, as schematically shown in FIG. 5, a large number of deformation wrinkles extending relatively long in the inclined direction are formed at short intervals in the direction in which the ridge line portions 12 face each other. That is, as compared with the conventional configuration that is bent and deformed relatively large in the cylinder axis direction, the energy absorbing member 10 is complicatedly deformed over a wide range when a compression load is input.

  As a result, the energy absorbing member 10 can improve the weight efficiency of energy absorption compared to the conventional case.

  Further, since the energy absorbing member 10 is deformed in a bellows shape in the cylinder axis direction in addition to the shear deformation, the amount of energy absorption is further increased, and its weight efficiency is greatly improved as compared with the conventional case. It will be.

  In this embodiment, the energy absorption member 10 has a triangular cross section, but the energy absorption member has a polygonal cross section in which the ridge line portions 12 and the flat surface portions 13 are alternately arranged in the circumferential direction. And what is necessary is just to form the junction part 14 between the ridgeline parts 12. FIG. Although illustration is omitted, the cross-sectional shape of the energy absorbing member can be appropriately set, for example, a quadrangular shape or a pentagonal shape.

(Embodiment 2)
FIG. 6 shows an energy absorbing member 20 according to the second embodiment. The energy absorbing member 20 has a main body 21 that is cylindrical. In the energy absorbing member 20, the high rigidity portion 22 and the low rigidity portion 23 are formed by making the thicknesses different.

  That is, the main body 21 is formed by arranging a high-rigidity portion 22 constituted by a relatively thick portion and a low-rigidity portion 23 constituted by a relatively thin portion in a predetermined arrangement. ing. Specifically, as shown schematically in FIG. 7 in which the cylindrical main body 21 is developed, a tongue extending from the end in the cylindrical axis direction toward the central portion in one area in the cylindrical axis direction. The two high-rigidity portions 22a are arranged at equal intervals, and in the other region in the cylindrical axis direction, the two tongue-like high-rigidity portions 22b are also provided with high rigidity in the one region. The position is shifted in the circumferential direction with respect to the portion 22a.

  As a result, the high-rigidity portion 22a in one region and the high-rigidity portion 22b in the other region are opposed to an oblique direction inclined with respect to the direction of the cylinder axis, and the high-rigidity opposed to the oblique direction. The low rigidity portion 23 is located between the portions 22a and 22b.

  The energy absorbing member 20, which is a cylindrical body having parts with different thicknesses, may be manufactured by, for example, integrally forming by a hydroform method, or formed by joining members having different thicknesses by welding, for example. You may manufacture by the tailored blank construction method.

  Also in this energy absorbing member 20, although illustration is omitted, when a compressive load is input to one end portion in the cylinder axis direction, the low-rigidity portion 23 between the high-rigidity portions 22 undergoes shear deformation, and the energy is absorbed. The weight efficiency of absorption can be improved.

  In addition, the number of the high rigidity parts 22 in an energy absorption member is not specifically limited, It is possible to set suitably. For example, as shown in a development view in FIG. 8, the interval between the high-rigidity portions 22 may be reduced by increasing the number of high-rigidity portions 22 as compared with the energy absorbing member shown in FIG.

  Further, the shape of the high-rigidity portion 22 is not particularly limited, and can be set as appropriate. For example, as shown in FIG. 9, each high-rigidity portion 22 may have a triangular shape that tapers from an end portion in the cylinder axis direction toward the central portion, and the low-rigidity portion 23 may be shaped like a band accordingly. Also in this case, the number of high-rigidity portions in the energy absorbing member can be set as appropriate. For example, as shown in FIG. 9, three high-rigidity portions 22 may be provided in each of one region and the other region in the cylinder axis direction. For example, as shown in FIG. One high rigidity portion 22 may be provided in each of one region and the other region.

(Embodiment 3)
FIG. 11 shows an energy absorbing member 30 according to the third embodiment. In the energy absorbing member 30, the main body 31 is cylindrical as in the second embodiment, but the high-rigidity portion 32 and the low-rigidity portion 33 are made of different materials.

  That is, the high-rigidity portion 32 is formed of a material having relatively high rigidity, whereas the low-rigidity portion 33 is formed of a material having relatively low rigidity. For example, the high rigidity portion 32 may be made of steel, and the low rigidity portion 33 may be made of aluminum.

  The energy absorbing member 30 composed of such dissimilar materials can be manufactured by appropriately adopting a technique for joining dissimilar materials to each other, such as welding or friction stir welding.

  Also in this energy absorbing member 30, although illustration is omitted, when a compressive load is input to one end portion in the cylinder axis direction, the low-rigidity portion 33 positioned between the high-rigidity portions 32 undergoes shear deformation. The weight efficiency of energy absorption can be improved.

  Note that the number and shape of the high-rigidity portions in the energy absorbing member 30 are not particularly limited as in the second embodiment.

(Embodiment 4)
FIG. 12 shows an energy absorbing member 40 according to the fourth embodiment. In the energy absorbing member 40 according to the fourth embodiment, the cylindrical member (main body) 41 is locally subjected to a quenching process, thereby creating a highly rigid portion 42 having relatively high rigidity.

  That is, a quenching process is locally performed at a predetermined position of the cylindrical main body 41, specifically, at a position that becomes a highly rigid portion hatched in FIGS. As a result, the rigidity is partially improved, so that the high-rigidity portion 42 having a relatively higher rigidity than other portions (that is, the low-rigidity portion 43) can be configured.

  Also in this energy absorbing member 40, although not shown, when a compressive load is input to one end portion in the cylinder axis direction, the low rigidity portion 43 located between the high rigidity portions 42 undergoes shear deformation. Thereby, the weight efficiency of energy absorption can be improved.

(Embodiment 5)
FIG. 13 shows an energy absorbing member according to the fifth embodiment. The energy absorbing member 50 is configured in multiple stages by abutting a plurality (three in the example) of energy absorbing members 10 (main body 11) shown in FIG. 2 so as to be coaxial with each other.

  When a compressive load in the cylinder axis direction is input to the multistage energy absorbing member 50 (see P1), as shown in FIG. 14, each of the main bodies 11 undergoes shear deformation (see P2), and then the main body 11 Each of these deforms into a bellows shape (see P3).

  The multistage energy absorbing member 50 can further improve the weight efficiency. Further, the length of the energy absorbing member 50 can be adjusted by adjusting the number of the main bodies 11 to be stacked.

  Note that a plurality of energy absorbing members may be configured by stacking a plurality of energy absorbing members 20, 30, and 40 shown in FIGS. 6, 11, and 12 so as to be coaxial with each other. Moreover, you may comprise a multistage energy absorption member not by stacking the energy absorption member of the same structure but by stacking the energy absorption member of a mutually different structure.

  As described above, since the weight efficiency of the energy absorbing member is improved, the present invention is useful, for example, as an energy absorbing member for constituting a part of a vehicle frame, particularly a front or rear frame.

It is a partially broken side view showing a front frame of a vehicle to which an energy absorbing member is applied. It is a perspective view which shows the energy absorption member which concerns on Embodiment 1. FIG. It is a left view of the said energy absorption member. It is explanatory drawing which shows an example of the manufacturing method of the said energy absorption member. It is explanatory drawing which shows a mode that the said energy absorption member deform | transforms. It is a perspective view which shows the energy absorption member which concerns on Embodiment 2. FIG. It is expansion | deployment explanatory drawing of the said energy absorption member. It is an expansion explanatory view of the energy absorption member concerning the modification of Embodiment 2. It is an expansion explanatory view of the energy absorption member concerning the modification of Embodiment 2. It is an expansion explanatory view of the energy absorption member concerning the modification of Embodiment 2. It is a perspective view which shows the energy absorption member which concerns on Embodiment 3. FIG. It is a perspective view which shows the energy absorption member which concerns on Embodiment 4. It is a perspective view which shows the energy absorption member which concerns on Embodiment 5. FIG. It is a perspective view which shows a mode that the said energy absorption member deform | transforms.

Explanation of symbols

10, 20, 30, 40 Energy absorbing member 11, 21, 31, 41 Main body 12 Ridge line part 13 Flat part 14 Joint part (low rigidity part)
22, 32, 42 High rigidity portion 23, 33, 43 Low rigidity portion 81 Mold 91 Front side frame (front frame)
92 Crash Can (front frame)

Claims (11)

A cylindrical main body comprising at least two relatively rigid and highly rigid portions, and a portion having a portion other than the highly rigid portion and a relatively low stiffness portion;
The high-rigidity portion is disposed on the peripheral wall of the main body in an oblique direction inclined with respect to the direction of the cylinder axis,
The low-rigidity part is disposed at least between the high-rigidity parts opposed to the oblique direction,
When a compressive load in the cylinder axis direction is input to the main body, the high rigidity parts opposed to the diagonal direction move so as to approach each other in the cylinder axis direction, so that the position is between the high rigidity parts. An energy absorbing member in which a low-rigidity portion that undergoes shear deformation. The energy absorbing member according to claim 1,
An energy absorbing member in which when the compressive load in the cylinder axis direction is input to the main body, the low-rigidity portion undergoes shear deformation and the entire main body deforms in a bellows shape in the cylinder axis direction. The energy absorbing member according to claim 1,
The main body has a polygonal cross section formed by alternately arranging a ridge line portion and a flat surface portion in the circumferential direction on the peripheral wall, and the ridge line portion is adjacent to the cylinder axis direction in the two regions. Are shifted from each other in the circumferential direction,
The energy-absorbing member, wherein the high-rigidity part is constituted by the ridge line part, and the low-rigidity part is constituted by the flat part. The energy absorbing member according to claim 1,
The high-rigidity part and the low-rigidity part are energy absorbing members having different thicknesses. The energy absorbing member according to claim 1,
The high-rigidity part and the low-rigidity part are energy absorbing members made of different materials. The energy absorbing member according to claim 1,
The high-rigidity part is an energy absorbing member formed by locally performing heat treatment on the side wall of the main body. The energy absorbing member according to claim 3,
The body having a polygonal cross section is formed by inserting a mold having a predetermined shape into a cylindrical member having openings at both ends in the direction of the cylinder axis and bending and deforming the peripheral wall of the cylindrical member. . The energy absorbing member according to claim 4,
An energy absorbing member in which a main body composed of a high-rigidity portion and a low-rigidity portion having different wall thicknesses is formed by a tailored blank method or a hydroform method. The energy absorbing member according to claim 5,
An energy absorbing member in which a main body composed of a high-rigidity portion and a low-rigidity portion made of different materials is formed by a welding method or a friction stir welding method. The energy absorbing member according to claim 1,
A plurality of main bodies composed of the high rigidity portion and the low rigidity portion are provided,
The plurality of main bodies are energy absorption members that are coaxially stacked. The energy absorbing member according to claim 1,
The main body is arranged so that the cylinder axis direction thereof coincides with the vehicle front-rear direction and constitutes a part of the front frame of the vehicle, and the low-rigidity part shear-deforms the collision load input to the vehicle. An energy absorbing member that absorbs by doing.

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