JP2014119064A - Energy absorption fastening structure - Google Patents

Abstract

[PROBLEMS] To efficiently absorb the energy of an external load applied to a component without significantly increasing the weight of the component by a simple structural improvement around the fastening portion of the component, and to greatly increase the amount of energy absorption. An energy absorption fastening structure capable of achieving the above is provided.
An energy absorption fastening structure having a fastening part to another member and absorbing energy of an external load applied to a part made of a material that can be sequentially broken through the fastening part. The thickness of the part itself is partially increased in a local area including at least a part of the expected sequential failure area due to external load in the peripheral part of the part, and a bead extending continuously in a predetermined specific direction is formed. An energy absorption fastening structure characterized by that.
[Selection] Figure 1

Description

  The present invention relates to an energy absorbing fastening structure that can efficiently absorb energy of an external load applied to a component through the fastening portion by adding a specific structure around the fastening portion of the component.

  In a structure in which a component is fastened to another member by a fastening member, destruction often proceeds from the fastening portion when a large external load is applied. In addition, it may be required to make use of this property so that the energy of the external load can be absorbed through the fastening portion or the peripheral portion thereof.

  For example, as shown in FIG. 3, a general part has a structure in which the part 21 is fastened to the other member 23 by a fastening member 22 made of a bolt or the like at a part where the part 21 is located. is there. In the case of having such a fastening structure, when an external load is applied in a certain direction of the component 21, a bearing load (for example, an arrow F in FIG. 3A) is applied to the inner surface of the bolt hole of the component 21 based on the external load. When the load F exceeds a certain level, destruction often proceeds. Although this breakage depends on the material of the component 21, if the component 21 is made of a material that can be sequentially broken (for example, a resin that can be broken sequentially), the fracture propagation as shown in FIG. Often proceed to region 24.

  In the process of destruction progressing as described above, the energy of the external load is absorbed. To increase the amount of energy absorption, the progression of sequential destruction as described above is delayed as much as possible. As a structure in which destruction does not proceed easily, it is necessary to absorb a large amount of energy before the entire destruction.

  In order to increase the amount of energy absorption based on such a concept, it is conceivable first to increase the thickness of the part 21 over the whole and increase the strength and rigidity of the part 21 over the whole. However, this method inevitably increases the weight of the component 21 and increases in the amount of material used, and is difficult to employ for components that require weight reduction as much as possible.

  As another method, for example, as shown in FIG. 4, ribs 26 are provided, for example, radially from the bolt peripheral portion 25 of the component 21, and in some cases, the ribs 26 are provided concentrically with respect to the bolt peripheral portion 25. It is conceivable to reinforce the periphery of the fastening portion by connecting to the reinforcing portion 27. However, with this method, it is relatively difficult to optimally design the ribs 26 and the reinforcing portions 27. Since the rib 26 is usually provided with a relatively thin thickness, the rib 26 may be broken (cracked) when a large load is applied to the rib 26 installation portion. Once any of the ribs 26 is broken, the strength and rigidity of the portion are rapidly reduced, and it is difficult to cause a desired sequential fracture for energy absorption in the portion.

  In addition, Patent Document 1 discloses a structure in which ribs are formed concentrically around the periphery of the fastening portion. However, the structure disclosed in Patent Document 1 is configured to receive an axial load from a fastener. It is a structure that is reduced by a load reducing body, and it is considered that it hardly contributes to the absorption of energy due to the above-described sequential destruction.

  In addition, Patent Document 2 discloses a structure in which a bush capable of absorbing energy is embedded in a fastening portion of a resin casing. In the structure disclosed in Patent Document 2, a material constituting the above-described component is disclosed. It is considered that it hardly contributes to the absorption of energy due to the sequential destruction of itself, and the manufacturing process may be complicated due to the bushing embedding.

JP 2012-200909 A JP 2005-163876 A

  Accordingly, the object of the present invention is to pay attention to the above-mentioned problems, and is applied to the component without significantly increasing the component weight by a simple structural improvement around the fastening portion of the component made of a material that can be sequentially broken. It is an object to provide an energy absorption fastening structure capable of efficiently absorbing energy of an external load and capable of greatly increasing the amount of energy absorption.

  In order to solve the above-described problems, an energy absorption fastening structure according to the present invention has a fastening portion to another member, and the energy of an external load applied to a component made of a material that can be sequentially broken is supplied to the fastening portion. An energy absorption fastening structure that absorbs through a part of a local region including at least a part of a region expected to sequentially break due to an external load in the periphery of the fastening portion of the component. And a bead that extends continuously in a predetermined specific direction is formed.

  In such an energy absorption fastening structure according to the present invention, the thickness of the component itself is partially in a local region including at least a part of the expected sequential failure region around the fastening portion of the component made of a sequentially breakable material. Since a bead that is continuously extended in a specific direction is formed, sequential breakage around the fastening portion that is about to be generated by propagation of an external load to the part is suppressed by the bead, As a result, a state in which sequential destruction is difficult to occur, or a state in which the amount of energy absorbed by sequential destruction is significantly increased as compared to a form without beads appears when sequential destruction occurs and progresses. . Since the bead only needs to be formed locally at the required site, the weight of the entire part is not increased significantly, and the energy of the external load applied to the part is efficiently absorbed by the bead formation. The amount can be greatly increased. Furthermore, by realizing desirable sequential destruction, parts can be prevented from being destroyed at once, which can contribute to improvement in safety.

  In the energy absorbing fastening structure according to the present invention, it is only necessary that the part to be fastened is made of a material that can be sequentially broken. Examples of such a material include a resin-containing material, and in particular, a thermoplastic resin. The material containing can be illustrated. As a resin as such a material that can be sequentially destroyed, for example, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN), polyester such as liquid crystal polyester, Polyolefins such as polyethylene (PE), polypropylene (PP), polybutylene, styrene resins, polyoxymethylene (POM), polyamide (PA), polycarbonate (PC), polymethylene methacrylate (PMMA), polyvinyl chloride (PVC), polyphenylene sulfide (PPS), polyphenylene ether (PPE), modified PPE, polyimide (PI), polyamideimide (PAI), polyetherimide (PEI), polysulfone (P U), modified PSU, polyethersulfone, polyketone (PK), polyetherketone (PEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyarylate (PAR), polyethernitrile (PEN) Fluorine resins such as phenolic resins, phenoxy resins, polytetrafluoroethylene, and thermoplastic elastomers such as polystyrene, polyolefin, polyurethane, polyester, polyamide, polybutadiene, polyisoprene, and fluorine. These copolymers, modified products, and resins obtained by blending two or more types may be used. In particular, a PC resin or ABS resin and a blended material thereof are more preferably used from the viewpoint of high elongation, and a polyamide resin and a blended material thereof are more preferably used from the viewpoint of high strength.

  In the energy absorption fastening structure according to the present invention, the extending direction of the bead can be set to a direction intersecting with the load direction of the external load or a direction along the load direction of the external load. It is also possible to set in both directions. What is necessary is just to set according to the said sequential destruction assumption area | region, and should just set to the most effective position and direction on energy absorption performance, suppressing the weight increase of the components accompanying bead installation as much as possible.

  The bead has only to be formed in a shape in which the thickness of the component itself is partially increased and continuously extends in a predetermined specific direction. As a cross-sectional shape of the bead, for example, it can be formed in a kamaboko shape. A kamaboko-shaped cross-sectional shape can avoid local stress concentration as much as possible, and can suppress an increase in weight relatively small.

  In the energy absorption fastening structure according to the present invention, a structure in which a collar is fitted around the fastening member in the fastening portion can be adopted. By fastening through the collar, it is possible to avoid the screw part of the fastening member from coming into direct contact with the inner surface of the hole of the component, and to distribute the load evenly when an external load is transmitted. Therefore, an excessive local load is prevented from being applied to the minute part, and smoother energy absorption is possible through the state.

  The type of the fastening member is not particularly limited, but a bolt can be typically used.

  Thus, according to the energy absorption fastening structure according to the present invention, a simple structure improvement around the fastening portion of a part made of a resin material, particularly a resin material, without significant increase in weight of the part, The energy of the external load can be efficiently absorbed around the fastening portion, and the energy absorption amount can be significantly increased.

It is the schematic sectional drawing (A) of the energy absorption fastening structure which concerns on one embodiment of this invention, and the schematic bottom view (B) of fastening components. It is the schematic sectional drawing (A) of the energy absorption fastening structure which concerns on another embodiment of this invention, and the schematic bottom view (B) of fastening components. It is the schematic sectional drawing (A) which shows the structure of the conventional general fastening part, and the schematic bottom view (B) of fastening components. It is a schematic bottom view of the fastening part of fastening parts which shows an example in the case of reinforcing a fastening part with a rib.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows an energy absorption fastening structure according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a part made of a material that can be successively broken, particularly a thermoplastic resin, and the part 1 is fastened to another member 3 by a bolt 2 as a fastening member. In this embodiment, the component 1 is formed in a substantially hollow structure having an open space 4 toward the other member 3 mainly for weight reduction. In this fastening structure, in this embodiment, an external load is applied to the component 1 in a specific direction, and a load F (bearing load) is applied to the hole 5 through which the bolt 2 is inserted in a specific direction. The As described above, a region 6 in which sequential destruction occurs is assumed around the fastening portion of the component 1 due to the load of the external load. A cross-section that extends continuously in a predetermined direction in which the thickness of the part 1 itself is partially increased in a local region including at least a part of the sequential failure assumed region 6 due to an external load, around the fastening portion. Kamaboko shaped beads 7 and 8 are formed integrally with the part 1 by molding. In this embodiment, the extending direction of the bead 7 is set in a direction intersecting with the load direction of the external load. If only the energy absorption of the load F is taken into consideration, only the bead 7 can be set. In the present embodiment, considering the case where a load in the direction opposite to the illustrated load F is applied, a bead 8 having a similar shape extending in parallel with the bead 7 is provided at a position opposite to the bead 7 with respect to the fastening portion. Is formed.

  In the energy absorption fastening structure according to the above embodiment, a bead (in the illustrated example, the bead 7 in particular) in a local region including at least a part of the expected sequential failure region 6 with respect to the expected sequential failure region 6 caused by the load F. Therefore, the sequential failure around the fastening portion that is to be generated by the propagation of the load due to the external load applied to the component 1 is suppressed by the bead 7, thereby generating the sequential failure. Difficult state is realized. In addition, when sequential destruction occurs and progresses, a state is realized in which the amount of energy absorbed by the sequential destruction is significantly increased as compared to the form without the beads 7. Since the bead 7 only needs to be formed locally with respect to the component 1 in consideration of the sequential destruction assumed region 6, the weight of the entire component 1 is not significantly increased. In this state, by forming the bead, the energy of the external load applied to the component 1 is efficiently absorbed, and the energy absorption amount can be greatly increased. Further, the bead formation prevents the component 1 from being destroyed at once, and the desired sequential destruction can be realized. Therefore, it is possible to contribute to the improvement of safety regarding the destruction of the component 1.

  FIG. 2 shows an energy absorption fastening structure according to another embodiment of the present invention. In the present embodiment, as in the embodiment shown in FIG. 1, the component 11 is fastened to the other member 13 by a bolt 12 as a fastening member, and is formed into a substantially hollow structure having an open space 14. An external load is applied in a specific direction, and a load F (bearing load) is applied in a specific direction to the hole 15 through which the bolt 12 is inserted. Due to the load of the external load, a region 16 in which sequential destruction occurs is assumed around the fastening portion of the component 11. A cross-section that has a thickness of the part 11 itself partially increased in a local region including at least a part of the sequential fracture assumed region 16 due to an external load in the vicinity of the fastening portion and continuously extends in a predetermined specific direction. Kamaboko-shaped beads 17 and 18 extending in parallel with each other are formed integrally with the part 11 by molding. In particular, in this embodiment, the extending direction of the beads 17 and 18 is set to a direction along the load direction of the external load.

  Thus, even if the extending direction of the beads 17 and 18 is set in a direction along the load direction of the external load, the beads 17 and 18 are formed in a local region including at least a part of the expected fracture region 16. As a result, a state in which sequential breakdown is difficult to occur is realized, or even when sequential breakdown occurs and progresses, the amount of energy absorbed by the sequential breakdown is significantly larger than that without the beads 17 and 18. An increased state is realized. Other actions and effects are in accordance with the embodiment shown in FIG.

  The energy absorption fastening structure according to the present invention can be applied to fastening parts in all fields where energy absorption of an external load is required.

1, 11 Parts 2, 12 Bolts 3 and 13 as fastening members 4, 13 Other members 4, 14 Spaces 5, 15 Holes 6, 16 Successive failure assumed regions 7, 8, 17, 18 Bead F Load

Claims (7)

  An energy absorption fastening structure that has a fastening portion to another member and absorbs energy of an external load applied to a component made of a sequentially breakable material via the fastening portion, and the fastening portion of the component In a peripheral region including at least a part of a region where the sequential damage is assumed due to the load of the external load, a bead that is partially increased in thickness and continuously extends in a predetermined specific direction is provided. An energy absorption fastening structure characterized by being formed.   The energy absorption fastening structure according to claim 1, wherein the component is made of a material containing resin.   The energy absorption fastening structure according to claim 1 or 2, wherein the component is made of a material containing a thermoplastic resin.   The energy absorption fastening structure according to any one of claims 1 to 3, wherein an extending direction of the bead is a direction intersecting a load direction of the external load or / and a direction along a load direction of the external load.   The energy absorption fastening structure according to any one of claims 1 to 4, wherein a cross-sectional shape of the bead is formed in a kamaboko shape.   The energy absorption fastening structure according to any one of claims 1 to 5, wherein a collar is fitted around the fastening member in the fastening portion.   The energy absorption fastening structure according to any one of claims 1 to 6, wherein a fastening member in the fastening portion is made of a bolt.

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