JP2015055258A - Energy absorption member and impact absorption device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an energy absorption member that is easily attached, and appropriately absorbs energy with respect to a load from an oblique direction.SOLUTION: A crush box 2 comprises a composite material with a resin reinforced by fibers, and absorbs impact energy by collapse in a front-back direction after receiving a load from a front side. The crush box includes: a truncated conical part 21 that is formed into a truncated conical shape with a central axis Ax along a front-back direction as a rotational symmetric axis, and of which the diameter is made smaller toward the front side; and a cylindrical part 22 that is formed into a cylindrical shape having the central axis Ax common to the truncated conical part 21, and is connected to the truncated conical part 21 on the front side of the truncated conical part 21.

Description

  The present invention relates to an energy absorbing member that is mounted on, for example, an automobile and absorbs impact energy at the time of a collision, and an impact absorbing device including the same.

  2. Description of the Related Art Conventionally, an impact absorbing device that is mounted on, for example, an automobile and absorbs an external impact is known. In this impact absorbing device, for example, an energy absorbing member formed in a cylindrical shape receives the impact load and compresses it in the axial direction to absorb the impact load (impact energy). As an energy absorbing member, a metal (for example, aluminum alloy) has been conventionally used, but in recent years, it has a more excellent energy absorbing performance and is made of a lightweight composite material (for example, fiber reinforced plastic). Is being developed and put into practical use.

  By the way, in such an energy absorbing member, when it is formed in a simple cylindrical shape, when an impact load is applied obliquely with respect to the axial direction, the impact load is applied only on one side. May not be crushed in a desired crushing form. That is, with a simple cylindrical energy absorbing member, when it receives an impact load that is biased to only one side, it breaks from unintended locations such as fine cracks that exist on the one side. As a result, the desired energy absorption performance may not be exhibited.

  Therefore, for example, in the energy absorbing member described in Patent Document 1, the tip end portion pressed by the pressing member has an area of the outermost end that is 2/3 or less of the cross-sectional area of the complete cylindrical portion, and the cross-sectional area is By adopting a shape that is obliquely cut so as to continuously change in the axial direction, a large amount of energy absorption can be secured even with respect to an oblique load.

JP-A-5-332385

  However, in the energy absorbing member having a shape in which the tip is cut obliquely, the mounting structure for a member (a vehicle body in the case of an automobile) that supports the tip side of the energy absorbing member is limited, that is, the mounting is difficult. turn into.

  The present invention has been made in view of the above-mentioned problems, and is easy to mount and can absorb energy suitably even with respect to a load from an oblique direction, and an impact absorbing device including the energy absorbing member The purpose is to provide.

In order to achieve the above object, the invention described in claim 1
An energy absorbing member that is composed of a composite material reinforced with resin and absorbs energy by receiving a load from one end side in a predetermined crushing direction and crushing in the crushing direction,
A frustoconical part formed in a truncated cone shape having a central axis along the crushing direction as a rotationally symmetric axis, and having a diameter decreasing toward one end side in the crushing direction;
A cylindrical portion that is formed in a cylindrical shape having a central axis common to the truncated cone portion, and is connected to the truncated cone portion on the one end side of the truncated cone portion;
It is characterized by having.

The invention according to claim 2 is the energy absorbing member according to claim 1,
The composite material is a carbon fiber reinforced plastic.

The invention according to claim 3 is an impact absorbing device,
The energy absorbing member according to claim 1 or 2,
A pressing member that is disposed in contact with an end face of the one end side of the cylindrical portion and presses the energy absorbing member in the crushing direction to be crushed;
It is characterized by providing.

According to the present invention, an energy absorbing member that receives a load from one end side in a predetermined crushing direction is formed in a truncated cone shape having a central axis along the crushing direction as a rotationally symmetric axis, and goes toward one end side in the crushing direction. A circular truncated cone part that is provided so that the diameter is reduced, and a cylindrical shape having a central axis common to the circular truncated cone part, and is provided on one end side of the circular truncated cone part connected to the circular truncated cone part. And a cylindrical portion. As a result, the load in the oblique direction acting on the energy absorbing member is transmitted to the truncated cone part while being distributed along the crushing direction through the cylindrical part, so that the conventional energy absorbing member that is a simple cylindrical shape and In contrast, the load does not act on one side only. Therefore, not only the load along the crushing direction but also the load from the oblique direction can be favorably absorbed.
Moreover, since the one end side of the energy absorption member which receives a load is a cylindrical part, it can be easily attached to the member which supports the said energy absorption member unlike the prior art from which this edge part was cut off diagonally.
Therefore, attachment is easy and the energy can be suitably absorbed even with respect to a load from an oblique direction.

1 is a perspective view of a vehicle equipped with an impact absorbing device in an embodiment. It is sectional drawing of the shock absorber in embodiment. It is a figure for demonstrating the energy absorption aspect when the load from diagonally forward acts on the shock absorber in embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view of a vehicle 100 on which the shock absorbing device 1 according to the present embodiment is mounted, and FIG. 2 is a cross-sectional view of the shock absorbing device 1.

As shown in FIG. 1, two impact absorbing devices 1 are arranged between a bumper beam 101 and a body frame 102 of a vehicle (automobile) 100 to absorb an impact from the front of the vehicle.
In the following description, “front” and “rear” refer to directions as viewed from the vehicle 100 on which the shock absorbing device 1 is mounted unless otherwise specified.

  Specifically, as shown in FIG. 2, the impact absorbing device 1 includes a crash box 2, a pressing member 3 that presses the crash box 2, and a support member 4 that supports the crash box 2.

  The crash box 2 is an energy absorbing member according to the present invention, and is composed of fiber reinforced plastics (FRP) which is a composite material in which a resin is reinforced with fibers. Examples of the fiber include carbon fiber, glass fiber, basalt fiber, and aramid fiber, and it is preferable to use a carbon fiber excellent in energy absorption and strength. The crush box 2 absorbs the impact energy by being pressed from the front by the pressing member 3 receiving the impact load and crushed in the front-rear direction. Specifically, the crash box 2 is formed in a shape in which a truncated cone part 21 and a cylindrical part 22 are connected in the front-rear direction.

  Among these, the truncated cone part 21 is a part mainly exhibiting energy absorption performance in the crash box 2 and occupies most of the length in the front-rear direction of the crash box 2. The truncated cone part 21 is formed in a hollow truncated cone shape having a substantially uniform thickness with the central axis Ax along the front-rear direction as a rotationally symmetric axis, and the diameter decreases toward the front. Is provided.

  On the other hand, the cylindrical portion 22 is a load input portion for receiving the impact load from the front of the crash box 2 and transmitting the impact load along the front-rear direction to the truncated cone portion 21. The cylindrical portion 22 has a central axis Ax common to the truncated cone portion 21 and is formed in a cylindrical shape having substantially the same thickness as the truncated cone portion 21, and the truncated cone portion is located on the front side of the truncated cone portion 21. It is connected to the portion 21 (that is, the inner and outer peripheral surfaces are continuous). Moreover, the cylindrical part 22 contains the fiber wound by the circumferential direction at least. In addition, the front end surface of the cylindrical part 22 pressed by the pressing member 3 at the time of an initial press can be made into the shape according to the desired crushing form of the crash box 2, and although not shown in figure, it inclines in a taper shape, for example It may be formed in a tapered shape.

  The pressing member 3 is for pressing and crushing the crash box 2 and is formed in a substantially flat plate shape orthogonal to the front-rear direction, and extends over the entire front end surface of the crash box 2 (cylindrical portion 22). It arrange | positions so that it may contact | abut. The pressing member 3 is also a part where the impact absorbing device 1 is attached to the vehicle 100, and is attached to the bumper beam 101 so that the front surface is in contact with the rear surface of the bumper beam 101 of the vehicle 100 (see FIG. 1). Therefore, as will be described later, the pressing member 3 receives an impact load applied from the front via the bumper beam 101 and presses the crush box 2 from the front to crush it. As a method of fixing the crash box 2 to the bumper beam 101, for example, the pressing member 3 and the support member 4 are restrained by bolts, thereby generating a surface pressure on the crash box 2 and the pressing member 3 to There are ways to fix it.

  The support member 4 is for supporting the crash box 2, is formed in a substantially flat plate shape orthogonal to the front-rear direction, and abuts the rear end surface of the crash box 2 (the truncated cone part 21) over the entire circumference. Are arranged as follows. The support member 4 is also a part where the impact absorbing device 1 is attached to the vehicle 100, and is attached to the body frame 102 so that the rear surface abuts the front surface of the body frame 102 of the vehicle 100 (see FIG. 1).

  In the impact absorbing device 1 having the above configuration, for example, when the vehicle 100 equipped with the impact absorbing device 1 collides obliquely with a front object, as shown in FIG. An impact load from an obliquely inclined direction is applied to the pressing member 3 via the bumper beam 101. And the pressing member 3 which received this impact load presses the crash box 2 from diagonally forward along the direction of the impact load.

  Then, the load from the diagonally forward acting on the crash box 2 is to break the fiber wound in the circumferential direction into a roll shape when crushing the cylindrical portion 22 which is a load input portion of the crash box 2. The direction is changed along the front-rear direction following the roll direction. That is, the load from the oblique front is transmitted to the truncated cone part 21 while being distributed along the front-rear direction through the cylindrical part 22. For this reason, the load does not act on the truncated cone portion 21 only on one side.

  And as shown in FIG.3 (b), as for the crush box 2, fiber is fractured | ruptured from the front part of the cylindrical part 22 pressed directly by the press member 3, and the broken piece is divided into the inside and outside, and it is wound back. Crush sequentially. As a result, the impact energy is absorbed by the crushing of the crash box 2, and the impact load is buffered. At this time, the frustoconical portion 21 of the crash box 2 has a monotonous increase in the area pressed by the pressing member 3 as it is crushed, so that the crushing load increases monotonously with respect to the displacement in the front-rear direction. Energy absorption characteristics can be obtained.

As described above, according to the present embodiment, the crash box 2 that receives a load from the front side is formed in a truncated cone shape having the central axis Ax along the front-rear direction as a rotationally symmetric axis, and has a diameter toward the front side. Is formed in a cylindrical shape having a central axis Ax common to the truncated cone part 21 and connected to the truncated cone part 21 on the front side of the truncated cone part 21. The cylindrical part 22 is provided. As a result, the load from the diagonally forward acting on the crash box 2 is transmitted to the truncated cone part 21 while being distributed along the front-rear direction through the cylindrical part 22, so that the conventional energy which has been a simple cylindrical shape Unlike the absorbing member, the load does not act only on one side. Therefore, not only the load along the front-rear direction but also the load from obliquely forward can absorb the energy suitably.
Further, since the front side portion of the crash box 2 that receives the load is the cylindrical portion 22, unlike the conventional case where the end portion is cut off obliquely, a member (such as the pressing member 3 or the vehicle body) that supports the crash box 2 is used. Easy to install.
Therefore, attachment is easy and the energy can be suitably absorbed even with respect to a load from an oblique direction.

  Moreover, since the truncated cone part 21 is provided so that the diameter becomes smaller toward the front, the broken piece that is caught on the inner peripheral side when the crush box 2 is crushed is a larger space than the crushed part. It spreads to the bottom side of the truncated cone part 21. Therefore, the crushing pieces of the crush box 2 that have already been crushed do not accumulate and restrain new crushing pieces, and as a result, an unintended crushing load (load required for crushing) can be prevented from rising.

  The embodiments to which the present invention can be applied are not limited to the above-described embodiments, and can be appropriately changed without departing from the spirit of the present invention.

  For example, the detailed shape of the truncated cone part 21 may correspond to a desired energy absorption characteristic. For example, the crush load may be changed by changing the thickness (that is, the cross-sectional area) or the shape of the truncated cone part 21. .

  In addition, the energy absorbing member and the impact absorbing device according to the present invention are not limited to those mounted on a vehicle (automobile), and can be suitably applied to, for example, those mounted on a helicopter to absorb a landing impact. It is.

1 Shock absorber 2 Crash box (energy absorbing member)
21 frustoconical part 22 cylindrical part Ax central axis 3 pressing member 4 support member

Claims (3)

An energy absorbing member that is composed of a composite material reinforced with resin and absorbs energy by receiving a load from one end side in a predetermined crushing direction and crushing in the crushing direction,
A frustoconical part formed in a truncated cone shape having a central axis along the crushing direction as a rotationally symmetric axis, and having a diameter decreasing toward one end side in the crushing direction;
A cylindrical portion that is formed in a cylindrical shape having a central axis common to the truncated cone portion, and is connected to the truncated cone portion on the one end side of the truncated cone portion;
An energy absorbing member characterized by comprising:   The energy absorbing member according to claim 1, wherein the composite material is a carbon fiber reinforced plastic. The energy absorbing member according to claim 1 or 2,
A pressing member that is disposed in contact with an end face of the one end side of the cylindrical portion and presses the energy absorbing member in the crushing direction to be crushed;
An impact absorbing device comprising:

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