JP2013194792A - Energy absorbing body for vehicle collision time - Google Patents

Abstract

PROBLEM TO BE SOLVED: To further improve impact absorbing performance in an energy absorber for absorbing energy by being destroyed at the time of a vehicle collision.
An energy absorber according to the present invention is fitted into a hollow molded body made of a fiber-reinforced resin cylindrical wall extending outward from a support surface in a vehicle, and inside the molded body. There is a fitting portion and a pressing portion that is connected to the fitting portion and faces the cylindrical wall portion on the outer side in the axial direction of the molded body and breaks the cylindrical wall portion by an external force, and the destruction of the cylindrical wall portion proceeds. When the insertion portion reaches the support surface, the pressing portion further destroys the insertion portion.
[Selection] Figure 1

Description

  The present invention relates to an energy absorber that absorbs collision energy when a vehicle such as an automobile or an aircraft collides with a moving body. More specifically, the present invention includes a hollow molded body made of fiber reinforced resin. It relates to an energy absorber that alleviates impact by sometimes destroying the molded body.

  In vehicles or moving bodies such as automobiles and airplanes, various types of shock absorbing structures are provided in order to mitigate the impact at the time of collision. As one example of such a shock absorbing mechanism, an energy absorber made of a hollow cylindrical molded body is provided on the bottom surface of a vehicle bumper or an aircraft passenger's feet, and at the time of collision of a vehicle or a moving body, A mechanism is known in which a compact is broken by a compressive load due to a collision, thereby absorbing the collision energy. With respect to the impact absorbing structure by the energy absorber of the hollow cylindrical molded body, various configurations have been proposed in order to efficiently destroy the molded body and absorb larger energy. For example, in Patent Documents 1 and 2, a member that presses the molded body is configured so that a portion or a fragment of the molded body that is destroyed when the hollow molded body is crushed, Thereby, the energy absorber which aims at prevention of the scattering to the exterior of the part of a molded object or a fragment | piece, or the increase in energy absorption is disclosed. Further, in Patent Document 3, a part of a pressing member that applies a load to a cylindrical molded body is fitted into a hollow inside of the molded body, and the pressing member is widened in a direction away from the fitting portion into the molded body. Proposed is a configuration that absorbs energy efficiently by having a reduced diameter, and when the load is applied to the molded body from the pressing member, the molded body is broken while its diameter is enlarged. Furthermore, in patent document 4, in the structure which connects an impact-absorbing member to the bumper reinforcement of a vehicle, a bumper reinforcement is connected so that it can rotate relatively with respect to an impact-absorbing member (crash box), As a result, when a bending load is applied from the bumper reinforcement to the shock absorbing member, the bumper reinforcement rotates to suppress the bending deformation of the shock absorbing member, and smooth crushing and breaking of the shock absorbing member is achieved. In addition, it is shown that a bead is formed on the connecting member between the bumper reinforcement and the impact absorbing member, and energy is absorbed by buckling deformation of the connecting member after the impact absorbing member is crushed and broken.

JP2009-287749 JP-A-2005-47387 Japanese Patent Laid-Open No. 10-30669 JP2008-24084

  By the way, in the case of the collision energy absorption mechanism by the breakage of the hollow molded body as described above, the progressive fracture characteristic of FRP (fiber reinforced plastic) having a small amount of residual energy and a large amount of absorbed energy per weight can be advantageously used. Many. However, in the event of an oblique collision with the vehicle body or aircraft, for example, the driver may turn the steering wheel immediately before the collision to avoid collision with a guardrail on a car's power road or collision with another vehicle. In the case of a ground collision due to an abnormality during takeoff of an aircraft, in addition to the load perpendicular to the collision surface, a sliding load acts in the tangential direction of the collision surface, reducing the amount of energy absorbed. obtain. More specifically, when a lateral load in the tangential direction of the collision surface acts on the energy absorber in addition to the axial load, the front surface of the energy absorber gradually moves as the energy absorber collapses. It will tilt. At that time, particularly in the case of an FRP energy absorber that undergoes progressive fracture, the collapsed surface is inclined and a lateral load is applied to the collapsed surface, whereby a bending load acts on the wall surface of the energy absorber. If it does so, the destruction piece of an energy absorber will become large and will lead to the fall of absorbed energy. Further, when the lateral load is significant, the energy absorber falls down and loses the energy absorbing function at that time.

  Therefore, in the past, in order to maintain the energy absorption efficiency of the FRP energy absorber, a metal plate or the like is inserted in order to keep the front end surface of the energy absorber such as the rear surface of the bumper flat. It was. However, even in such a case, when a load acts in an oblique direction, the fracture surface that should be perpendicular to the axial direction of the energy absorber gradually shifts, and the energy absorption efficiency may be reduced (FIG. 3). reference). Further, for example, as in Patent Documents 3 and 4, by inserting a part of the pressing member that applies a load to the cylindrical energy absorber (hollow molded body) at the time of collision into the tip of the energy absorber to some extent, Although it becomes possible to keep the front end surface of the energy absorber flat with respect to the load in the oblique direction, the destruction of the energy absorber proceeds and the pressing member hits the support surface (of the energy absorber). There is a possibility that a reaction force is generated and an impact remains.

  Thus, one object of the present invention is to further improve the impact absorbing performance of an energy absorber that is composed of the hollow molded body as described above and absorbs collision energy by fracture.

  Another object of the present invention is to insert a part of the pressing member into the hollow molded body so that the tip surface of the energy absorber is kept flat even when a load is applied obliquely to the energy absorber as described above. In this configuration, it is possible to alleviate the impact caused by the reaction force when a part of the pressing member fitted in the hollow molded body reaches the support surface of the hollow molded body.

  According to the present invention, the above-described problem is an energy absorber for absorbing energy by being destroyed at the time of a vehicle collision, and a fiber-reinforced resin tube extending outward from a support surface in the vehicle A hollow molded body composed of a shaped wall, a fitting part fitted inside the molded body, a cylindrical wall part connected to the fitting part and facing the cylindrical wall part on the outer side in the axial direction of the molded body by an external force This is achieved by an energy absorber characterized in that when the destruction of the cylindrical wall portion proceeds and the fitting portion reaches the support surface, the pushing portion further breaks the fitting portion. . In this configuration, the “support surface in the vehicle” is, for example, a bumper such as an automobile, bumper reinforcement, front side member, and the bottom surface of the aircraft body on the front side of the occupant's foot, so that it receives an impact when the vehicle collides. It may be an arbitrary part. The cylindrical wall portion of the hollow molded body may be cylindrical or rectangular.

  In the above configuration, the pressing portion is attached to the outer end of the hollow molded body extending outward from the support surface, and connected to the pressing portion to the inside of the molded body in the axial direction. An insertion part will be extended. Then, even if the pressing portion receives a load from an oblique direction with respect to the cylindrical axial direction, the influence of the lateral load is reduced due to the presence of the fitting portion, and the cylindrical wall portion is efficiently destroyed in the axial direction. It becomes. And when destruction of a cylindrical wall part advances and an insertion part arrives at a support surface, since a press part further destroys an insertion part and advances, an insertion part reaches a support surface. In this case, the reaction force is greatly reduced, and further shock relaxation is expected.

  Regarding the destruction of the insertion portion after reaching the support surface of the insertion portion, as a more preferable configuration, the insertion portion is formed in a cylindrical shape, and the insertion portion is the connection portion between the insertion portion and the pressing portion. You may have the peripheral part which the inner wall and the end surface crossed and formed and protruded inside the press part. Note that, in such a peripheral portion, the inner wall surface and the end surface of the insertion portion typically intersect at an acute angle, and the peripheral portion of the inner wall of the insertion portion is a complementary formed on the end surface of the pressing portion. It is fitted into the recess. And when an insertion part arrives at the support surface of a molded object, a press part will fit inside an insertion part, destroying a peripheral part. In particular, when the peripheral portion has an acute angle, when the insertion portion receives a compressive load between the pressing portion and the support surface, the peripheral portion rapidly collapses and presses inside the cylindrical insertion portion. The part is easy to progress.

  As another aspect of the present invention, a head portion having an outer surface with a low friction coefficient may be provided outside the pressing portion. When such a head part is provided, the frictional force in the direction along the surface of the head part decreases between the object and the head part even if the object comes in contact from an oblique direction during a vehicle collision. It is expected that the directional force is less likely to be transmitted to the energy absorber, thereby further reducing the influence of the lateral load on the energy absorber.

  By the way, when the cylindrical wall part of a molded object is a product made from CFRP (carbon fiber reinforced resin), since the used resin is often a thermosetting epoxy resin, fine pulverized pieces are easily scattered around. Therefore, in the energy absorber of the present invention described above, the side portion of the pressing portion and the outer surface of the molded body may be surrounded and covered with a flexible cover. Such a cover is advantageous because it prevents scattering of the fragments when the molded body is broken.

  Thus, according to the present invention described above, even if an external force is applied to the axial direction of the cylindrical wall portion due to an oblique collision of the vehicle (or the fuselage), the fracture surface of the cylindrical wall portion is used as the axis. On the other hand, the possibility of deviating from a vertical plane or the possibility of bending of the cylindrical wall portion is reduced, and more efficient energy absorption is expected in the process of breaking the molded body. In particular, when the insertion portion for suppressing the inclination of the fracture surface of the cylindrical wall portion is present inside the cylindrical wall portion, the cylinder is usually at the time when the insertion portion reaches the support surface of the molded body. When the destruction of the wall portion is completed and a reaction force due to the contact between the fitting portion and the support surface can be generated, the tubular wall portion is further broken by the pressing portion by the configuration in which the fitting portion is further broken by the pressing portion. Reduction of the reaction force due to the contact between the insertion portion and the support surface is achieved.

  Other objects and advantages of the present invention will become apparent from the following description of preferred embodiments of the present invention.

FIG. 1A is a schematic side cross-sectional view of the energy absorber of the present invention, and FIG. 1B is a schematic enlarged cross-sectional view of a connection portion between the facing portion 2 and the fitting portion 3. is there. 2A to 2C are schematic side cross-sectional views of the state of progressive fracture of the energy absorber of the present invention. FIG. 3 is a schematic side sectional view showing a state when a load is applied from an oblique direction in a conventional energy absorber.

1 ... FRP pipe material (tubular wall)
2 ... Destruction guide part (pressing part)
2a ... Depression of the destruction guide part 3 ... Rotation suppression guide part (insertion part)
3a: Peripheral portion of rotation suppression guide portion 3b: End surface of rotation suppression guide portion 3c ... Inner wall of rotation suppression guide portion 4 ... Head portion 5 ... Cover 6 ... Mounting base (support surface)
7 ... External impact object 11 ... Metal flat plate S ... Hollow part R ... Contact part with pipe material of fracture guide part

  The present invention will now be described in detail with reference to a few preferred embodiments with reference to the accompanying drawings. In the figure, the same reference numerals indicate the same parts.

Configuration of Energy Absorber Referring to FIG. 1 (A), the energy absorber of the present invention has a basic configuration in which an FRP pipe material 1 constituting a cylindrical wall portion has one end thereof. In this case, it is fixed to the mounting base 6 so as to extend outward in the axial direction, and the destruction guide part (pressing part) 2 is attached to the outer end. The mounting base 6 is typically an arbitrary part that comes into contact with an impact object first, such as a bumper of a car, a bumper reinforcement, a front side member, an aircraft, in the event of an aircraft ground collision or automobile collision. It may be attached to the airframe bottom portion on the passenger's foot front side.

  In short, the energy absorber as described above is the force exerted by the colliding object to the destruction guide portion 2 or the contact of the external structure (such as the outer wall of the vehicle) of the destruction guide portion 2 when the vehicle collides. As a result, the destruction guide portion 2 presses the pipe material 1 and proceeds toward the mounting base 6 while destroying the pipe material 1, thereby consuming energy. The consumption of collision energy by the energy absorber protects the vehicle structure and / or occupant in front of the energy absorber (as viewed from the collision object) from the impact of the collision. Thus, in the energy absorber, it is preferable that the pipe material 1 is less crushed and has a large absorbed energy amount (energy consumption amount) per weight. In this regard, for example, a ground collision due to an abnormality during takeoff of an aircraft, a collision with a guardrail on a curved road of a car, a collision with another car when a driver who tries to avoid the collision immediately before the collision turns the steering wheel For example, when there is a collision in the oblique direction with respect to the vehicle, a load acts on the transverse direction with respect to the axial direction of the pipe material 1 of the energy absorber. Then, the fracture surface or the crushing surface of the pipe material 1 is inclined from the surface perpendicular to the axial direction of the pipe material 1, and thereby, a large bending load acts on the wall surface of the pipe material 1, thereby using the pipe material 1. In the case of FRP, the broken pieces of the pipe material 1 become large, and the amount of absorbed energy per weight can be reduced (the finer the pieces, the more energy consumed for destruction). In addition, when the bending load is significant, the pipe material 1 may be buckled in the lateral direction without being crushed (when buckling occurs, the pipe material 1 is not further destroyed and energy consumption is stopped. .)

  Therefore, in the present invention, not only the axial force of the pipe material 1 but also a load transverse to the axial direction is applied, the surface is perpendicular to the axial direction of the pipe material 1. In order to suppress the inclination of the fracture surface of the pipe material 1 as much as possible, the configuration of the energy absorber is improved.

  Specifically, first, the head portion 4 is provided outside the destruction guide portion 2 that receives the contact force due to the collision first. The head portion 4 may be a member such as a pad made of a material having a low friction coefficient. When the head portion 4 receives a contact force from an oblique direction with respect to the axial direction of the pipe material 1, a lateral friction force component of the contact force is generated. Almost no transmission to the head portion 4 is achieved, and thus the lateral load transmitted to the pipe material 1 is reduced.

  Furthermore, in the energy absorber of the present invention, the rotation suppression guide part (insertion part) 3 is slidably inserted further into the destruction guide part 2 inside the pipe member 1. The rotation suppressing guide portion 3 is connected to the fracture guide portion 2, and when the fracture guide portion 2 exerts a lateral load on the pipe material 1, the same lateral load is exerted on the inner wall of the pipe material 1 that is in contact. Therefore, the bending moment in the pipe material 1 is reduced, and the moment of the breaking guide portion 2 is increased by the integral movement from the breaking guide portion 2 to the rotation suppressing guide portion 3 (the arm length is broken). It is the length from the guide part 2 to the tip of the rotation suppression guide part 3.) Since the movement of the destruction guide part 2 in the inclination direction is suppressed, the fracture of the pipe material 1 is prevented without tilting the fracture surface of the pipe material 1. Will proceed in the axial direction.

  Further, the influence of the bending moment of the lateral load applied to the fracture guide portion 2 increases as the pipe material 1 is closer to the root of the mounting base 6, and the pipe material 1 is more likely to buckle at the root. . Therefore, in order to prevent the buckling of the pipe material 1 by increasing the reaction force against the lateral load at the base of the pipe material 1, it is preferable that the base plate of the pipe material 1 as shown in FIG. The thickness may be increased.

  Furthermore, the outer diameter of the fracture guide portion 2 is set in the region R where the fracture guide portion 2 and the pipe material 1 are in contact so that the fracture of the pipe material 1 in the fracture guide portion 2 can be quickly achieved. It may be designed to expand smoothly. As a result, when the fracture guide portion 2 presses the tip of the pipe material 1, the pipe material 1 is crushed while receiving radial stress along the expanding outer diameter of the fracture guide portion 2 sequentially from the tip, and efficiently. Energy can be absorbed. In that case, since the crushed pieces of the pipe material 1 are discharged in the radial direction of the pipe material 1, the side surface of the fracture guide portion 2 is prevented in order to prevent the pieces of the pipe material 1 from being scattered outside. A flexible cover that covers the entire pipe material 1 extending from the mounting base to the mounting base, for example, a cloth material, a leather material, and a metal bellows material may be provided.

  By the way, as described above, in the energy absorber of the present invention, in order to prevent the inclination of the fracture surface of the pipe material 1 and the buckling, it is connected to the fracture guide portion 2 in the pipe material 1 and the rotation suppression guide. Part 3 is inserted. In that case, when the breakage of the pipe material 1 proceeds and the rotation suppression guide portion 3 comes into contact with the mounting base 6, the reaction force increases from the mounting base 6 toward the breaking guide portion 2, and the shock absorption capacity decreases. . Therefore, in the present invention, after the rotation suppression guide portion 3 and the mounting base 6 are contacted, the destruction guide portion 2 may be advanced while also destroying the rotation suppression guide portion 3. For this purpose, the rotation suppression guide portion 3 is preferably formed in a cylindrical shape like the pipe material 1. Further, in order to facilitate the destruction of the rotation suppression guide portion 3 by the destruction guide portion 2, as shown in FIG. 1B, in the contact area between the destruction guide portion 2 and the rotation suppression guide portion 3, The peripheral edge portion 3a of the rotation suppression guide portion 3 has an end surface 3b and an inner wall surface 3c that intersect each other at an acute angle (in a cross section) and protrude in the axial direction. It may be adapted to be fitted into a recess 2 a formed on the end face of the part 2. With this configuration, as will be described later, when the rotation suppression guide portion 3 receives a compressive load between the breakage guide portion 2 and the mounting base 6, the breakage guide portion 2 is easily started to break at the peripheral edge portion 3 a. Further advances in a direction approaching the mounting base 6, and a reduction in reaction force and further absorption of impact energy when the rotation suppression guide portion 3 comes into contact with the mounting base 6 are achieved.

Destruction Process of Energy Absorber (1) Conventional Energy Absorber Referring to FIG. 3, in the conventional energy absorber, the load (oblique load) is oblique from the direction of the axis of the pipe material 1. ), The metal flat plate 11 may be arranged at the tip of the pipe material 1 so that the fracture surface of the pipe material 1 does not tilt. However, when the metal flat plate 11 is simply disposed, when the oblique load is applied, the fracture surface of the pipe member 1 is gradually inclined as illustrated. More specifically, in the structure of FIG. 3, when an external collision object 7 contacts the head portion 4 at the tip of the pipe material 1 and an oblique load f <b> 1 acts, A rotational moment in the rotating direction acts, and the vertical reaction force becomes uneven (f2> f3). The progress of the destruction of the pipe material 1 corresponds to the reaction force, and therefore, the progress of the destruction of the wall portion of the upper pipe material 1 in the figure becomes faster, and the fracture surface of the pipe material 1 gradually increases. In this case, a bending moment is applied to the wall portion of the pipe material 1, and the size of the crushed pieces is increased, resulting in a decrease in energy consumption (absorption amount) per length. At this time, when the frictional forces f4 and f5 are generated in the metal flat plate 11, the fracture of the pipe material 1 proceeds at the interface between the metal flat plate 11 and the pipe material 1, so that the friction coefficient is small and the frictional force f4. , F5 is smaller than the oblique load f1, and if the inclination of the fracture surface of the pipe material 1 increases, the metal flat plate 11 may slip and fall off from the tip of the pipe material 1.

(2) In the case of the energy absorber of the present invention With reference to FIG. 2A, in the energy absorber of the present invention, when the external collision object 7 contacts the head portion 4 and acts on the oblique load f1, First, since the friction coefficient of the outer surface of the head portion is low, a significant reduction in the amount of lateral load transmitted from the external collision object 7 from the head portion 4 to the fracture guide portion 2 is expected. Further, when the rotational moment due to the oblique load f1 of the external collision object 7 acts on the fracture guide portion 2, a lateral force f6 acts on the side surface of the fracture guide portion 2 as a reaction force against the lateral load component of the oblique load f1, Since the lateral force f7 acts on the rotation suppression guide portion 3 due to the connection between the fracture guide portion 2 and the rotation suppression guide portion 3, the breakdown guide portion 2 and the rotation suppression guide portion 3 integrally rotate in the clockwise direction. Against the rotational moment due to the oblique load f1. If it does so, rotation by the diagonal load f1 of the fracture | rupture guide part 2 will be suppressed, and the bending moment inside the wall part of the pipe material 1 will also be reduced, and the fracture | rupture of the pipe material 1 will be carried out as FIG. 2 (A)-(B). While the breakage guide portion 2 and the rotation suppression guide portion 3 move and move through the hollow portion inside the pipe material 1, the inclination of the fracture surface of the pipe material 1 and the increase in the size of the crushed pieces are suppressed, which is efficient. Energy consumption by destruction will be achieved. In addition, the pipe material 1 is covered with the cover 5 during the progress of the destruction of the pipe material 1, so that the crushed pieces are prevented from being scattered outside.

  When the destruction of the pipe material 1 further proceeds from the state of FIG. 2B and the rotation suppression guide portion 3 contacts the mounting base 6, if the rotation suppression guide portion 3 is not destroyed, the pipe material 1 is destroyed. However, in the case of the present invention, as described above, the fracture guide portion 2 applies a pressing load to the rotation suppression guide portion 3 with the mounting base 6. Then, the inner wall of the rotation suppression guide portion 3 is broken while the inner wall of the rotation suppression guide portion 3 is inserted. If it does so, the increase in the reaction force when the rotation suppression guide part 3 contacts the attachment base 6 (axial direction) can be suppressed, and the further destruction of the pipe material 1 will proceed, thereby achieving greater energy absorption. Will be.

  Thus, according to the above-described configuration of the present invention, in the cylindrical energy absorber, the rotation suppression guide 3 is slidably fitted into the inner wall and / or the low friction coefficient is provided at the tip of the fracture guide portion 2. By mounting the head portion 4 having the outer surface, the inclination of the breaking guide portion 2 is suppressed, and when the rotation suppressing guide 3 reaches the mounting base 6, the rotation suppressing guide 3 is broken by the breaking guide portion 2. By doing so, the collision energy at the time of the vehicle collision is more efficiently absorbed, and the impact is mitigated.

  Although the above description has been made in relation to the embodiment of the present invention, many modifications and changes can be easily made by those skilled in the art, and the present invention is limited to the embodiment exemplified above. It will be apparent that the invention is not limited and applies to various devices without departing from the inventive concept.

Claims (4)

An energy absorber for absorbing energy by being destroyed at the time of a vehicle collision,
A hollow molded body comprising a cylindrical wall portion made of fiber-reinforced resin extending outward from a support surface in the vehicle;
A fitting part fitted inside the molded body, a pressing part connected to the fitting part and facing the cylindrical wall part on the outer side in the axial direction of the molded body, and destroying the cylindrical wall part by an external force;
Have
When the destruction of the cylindrical wall portion proceeds and the insertion portion reaches the support surface, the pressing portion further destroys the insertion portion.   2. The energy absorber according to claim 1, wherein a head portion having an outer surface with a low friction coefficient is provided outside the pressing portion.   It is an energy absorber of Claim 1 or 2, Comprising: The said insertion part is a cylinder shape, In the connection part of the said insertion part and the said press part, the said insertion part cross | intersects the inner wall and an end surface. The peripheral portion is formed and protrudes inside the pressing portion, and when the fitting portion reaches the support surface, the pressing portion fits inside the fitting portion while destroying the peripheral portion. Energy absorber.   2. The energy absorber according to claim 1, wherein a side portion of the pressing portion and an outer surface of the molded body are surrounded and covered by a flexible cover.

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