JP2001182769A - Shock absorbing member - Google Patents

Abstract

(57) [Problem] To provide a lightweight shock absorbing member having good shock absorbing characteristics, which is a shock absorbing member used for a crash box, a bumper reinforcement, a frame and the like of an automobile. SOLUTION: The shock absorbing member 1 includes a member main body 10 made of a rectangular hollow metal member 11 having a hollow portion 12, and a hollow portion 12;
And a filler 20 filled therein. Filler 20 is
Consists of balsa wood pieces 21. And, in the state where the wooden piece 21 is filled in the hollow portion 12,
The direction B of the fiber in the wood piece is substantially parallel to the direction of the impact load A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bumper reinforcement, a crash box,
The present invention relates to a shock absorbing member suitably used for a frame.

[0002]

2. Description of the Related Art For example, an impact absorbing member used in a crash box of an automobile is made of a hollow metal material having a rectangular cylindrical shape, and receives an impact load acting upon a collision as, for example, an axial compression load. It is intended to absorb the collision energy by regularly buckling and deforming in a bellows shape by a compressive load in the direction.

In the case of a light collision in which an automobile collides at a relatively low speed of 15 km / h or less, for example, the load (axial compression load) shown in FIG. )-Displacement curve
F), the maximum load generated in the early stage of buckling is equal to the average value (average load) of the subsequent load fluctuation,
In addition, a characteristic is desired in which the load does not fluctuate greatly and the load is constant irrespective of the increase in the displacement. In the figure, the area between the curve and the displacement axis corresponds to the amount of collision energy absorption, and the larger the area, the more the shock absorbing member can absorb the collision energy.

[0004] However, a crash box consisting only of a rectangular hollow metal material has a load-displacement curve of "".
As shown in FIG. 7, the maximum load generated in the initial stage of buckling is large, and the load fluctuates significantly thereafter. Therefore, the ideal shock absorption characteristic as described above is obtained. Therefore, conventionally, in order to improve the impact absorption characteristics, a filler made of a synthetic resin molded body such as a urethane foam molded body was filled in the hollow portion of the hollow material as a crush box. Things were used.

[0005]

However, the conventional crash box in which the filler is made of a molded article made of synthetic resin has not been able to obtain sufficiently satisfactory impact absorption characteristics. In particular, in recent years, it has been desired to reduce the weight of automobiles. However, it has not been possible to achieve a sufficient reduction in weight of a conventional crash box in which a filler is made of a synthetic resin molded body.

The present invention has been made in view of the above-mentioned technical background, and an object of the present invention is to provide a shock absorbing member used for a crash box, a bumper reinforcement, a frame, and the like of an automobile. An object of the present invention is to provide a lightweight shock absorbing member having absorbing characteristics.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a shock absorbing member including a member body made of a metal hollow material having a hollow portion and a filler filled in the hollow portion. Wherein the filler is made of a wooden material.

According to this, since the filler is made of a woody material, the shock absorbing characteristics are improved, and
Lightening is achieved.

Further, in the present invention, when the direction of the fibers in the filler is substantially parallel to the direction of the impact load in a state where the filler is filled in the hollow portion, the impact absorption characteristics are reduced. Further improve.

In the present invention, when the woody material is balsa wood, the weight can be significantly reduced.

In the present invention, as the filler, for example, a filler made of a woody material such as a piece of wood corresponds.

[0012]

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a shock absorbing member (1) of this embodiment. This shock absorbing member (1) is used as a crash box (see FIGS. 4 to 6; 33) of a front bumper of an automobile as described later.

This shock absorbing member (1) is shown in FIGS.
As shown in (1), a member body (10) made of a rectangular tubular hollow member (11) having a predetermined length and having a hollow portion (12), and a filler (20) filled in the hollow portion (12) Receiving an impact load (a) at the time of a collision as a compressive load in the axial direction (that is, the length direction of the member main body), and buckling deforming in a bellows shape by the axial compressive load. , It is intended to absorb the collision energy.

The hollow member (11) constituting the member body (10) is made of aluminum (including its alloy, the same applies hereinafter).
As shown in FIG. 2, the extruded section is made of an extruded section, and has a longitudinally extending partition plate (11a) which divides a hollow part (12) into two parts. , The cross-sectional shape of which is formed substantially in the shape of a letter.

The filler (20) comprises a total of two substantially rectangular parallelepiped wooden pieces (21) cut out from balsa wood, and each hollow portion (12) of the member body (10).
It is formed in such a size that it can be fitted almost exactly or slightly tightly. In the same figure, (b) indicates the direction of the fiber in the wood piece (21). The filler (20) is arranged such that the direction (b) of the fiber in the wood piece (21) is substantially parallel to the length direction (that is, the axial direction) of the member body (10). The hollow part (12) of (10) is fitted and filled. As described above, the shock absorbing member (1) is arranged to receive the impact load (a) at the time of collision as an axial compressive load, as described above. In 1), in a state where the filler (20) is fitted into the hollow portion (12) of the member main body (10), the direction (b) of the fiber in the wood piece (21) is changed at the time of collision. It is substantially parallel to the direction of the impact load (a).

The shock absorbing member (1) configured as described above has excellent shock absorbing characteristics because the filler (20) is made of a piece of wood (21). The reason will be described based on the stress-volume strain curve shown in FIG.

In FIG. 1, "c" indicates a stress-volume strain curve when a load is applied to a piece of wood in parallel with the direction of the fiber. "D" indicates a stress-volume strain curve when a load is applied to a piece of wood perpendicular to the direction of the fiber. "E" indicates a stress-volume strain curve when a load is applied to a urethane foam molded article which is one of the objects having no direction with respect to mechanical properties.

In the figure, the section substantially parallel to the volume strain axis in each curve "c, d, e", that is, the horizontal section, is a section where the stress takes a substantially constant value irrespective of an increase in the volume strain (stress constant). Section), and the longer this horizontal section is,
The load fluctuation generated at the time of buckling deformation of the shock absorbing member can be suppressed for a long time.

Thus, as can be seen from FIG.
Both the curve “d” and the curve “d” have a significantly longer horizontal section than the curve “e”. Therefore, the shock absorbing member (1) of this embodiment provided with the filler (20) made of the wood piece (21) has a good shock absorbing characteristic in which the load fluctuation generated during buckling deformation is suppressed for a long time. It has what has.

Further, comparing the curve "c" with the curve "d", it is understood that the stress value in the horizontal section of the curve "c" takes a larger value than that of the curve "d". Therefore, the direction (b) of the fiber in the piece of wood (21) is made parallel to the direction of the impact load (a), so that the piece of wood (2)
By fitting 1) into the hollow portion (12) of the member body (10), the average load of the shock absorbing member (1) is increased,
The shock absorption characteristics are improved. Therefore, the shock absorbing member (1) of this embodiment has a high average load and has extremely good shock absorbing characteristics.

In addition, in the shock absorbing member (1), since the member main body (10) is made of a hollow member made of extruded aluminum, it is lightweight, and the member main body (10) can be efficiently and efficiently formed. It can be manufactured cost-effectively. Further, since the filler (20) used in the shock absorbing member (1) is made of balsa wood (21), it is extremely lightweight.

FIGS. 4 to 6 show this shock absorbing member (1) as a crash box (33) for a front bumper of an automobile.
Is used.

In FIG. 4, reference numeral (32) denotes a rod-shaped bumper reinforcement having a length substantially equal to the width of the vehicle body, and is horizontally disposed at a predetermined height position on the front of the vehicle body (30). (31) (31) are left and right side members, which are disposed at the front end of the vehicle body (30). As shown in FIGS. 5 and 5, a crash box (33) is provided between the bumper reinforcement (32) and the side member (31). It is interposed so as to be substantially parallel to the front-back direction of 30). Therefore, as shown in FIG. 6, this crash box (33) is used as a bumper reinforcement (32).
The direction (b) of the fiber in the wood piece (21) constituting the filler (20) is substantially parallel to the front-rear direction of the vehicle body (30) in a state interposed between the side member (31) and the side member (31). It has become.

In FIG. 5, (W1) indicates that the crash box (33) is connected to the bumper reinforcement (3).
2) shows a welded portion fixed, and (W2) shows a welded portion where the crush box (33) is fixed to the side member (31).

When the vehicle is running at a low speed (for example,
km / h or less) (see FIG. 6), a collision with a wall-shaped obstacle (not shown) is carried out via a bumper reinforcement (32). An impact load (a) in a direction parallel to the length direction of the main body (10) is applied, and the crush box (33) is buckled and deformed in a bellows shape under the impact load (a). Absorbed. During this collision, the hollow portion (1) of the member body (10) of the crash box (33)
In 2), a filler (20) made of a piece of wood (21) is filled in a predetermined direction, so that the collision energy can be largely absorbed. Therefore, by using the shock absorbing member (1) as the crash box (33), a highly safe bumper device can be provided.

The embodiment of the present invention has been described above.
The present invention is not limited to the above embodiment, and various settings can be changed.

For example, the shock absorbing member according to the present invention
It may be used not only for the body frame of an automobile, but also for components other than the automobile. Furthermore, the member body has a rectangular cross section,
It may be formed of a metal hollow material having a cross-sectional shape or a circular cross-section.

[0029]

[Evaluation Example] In this evaluation example, a comparison was made between the shock absorbing characteristics of the shock absorbing member (1) shown in FIG. 1 (Example 1) and the shock absorbing characteristics of the conventional shock absorbing member (Comparative Example 1). ing. <Embodiment 1> In the shock absorbing member (1) of Embodiment 1, as the member main body (10), an extruded aluminum material (material: A6) is used.
063-T5) hollow material (a size x b size: 40 x 4)
0 mm, c size: 120 mm, wall thickness t = 2 mm), and a balsa wood piece (21) is used as the filler (20). <Comparative Example 1> In the shock absorbing member of Comparative Example 1, a hollow member made of an extruded aluminum material (material: A6063-T5) having the same dimensions and the same shape as the hollow member used in Example 1 was used as a member main body. On the other hand, a foamed urethane molded body is used as a filler.

An axial compressive load was applied to the shock absorbing member of Example 1 and the shock absorbing member of Comparative Example 1 as an impact load (a), and the energy absorption of each shock absorbing member was examined. Table 1 shows the results together with the weight of each shock absorbing member.
Are shown together. In the table, the energy absorption amount of each shock absorbing member is indicated by the energy absorption amount when each shock absorbing member receives an impact load and the c dimension of the shock absorbing member is compressed to 60 mm.

[0031]

[Table 1]

As shown in the table, it was found that the shock absorbing member (1) of Example 1 had a higher energy absorption than that of Comparative Example 1, and therefore had good shock absorbing characteristics. . Furthermore, it was found that the shock absorbing member (1) of Example 1 had an advantage that the weight was lighter than that of Comparative Example 1.

[0033]

As described above, according to the present invention, the shock absorbing member according to the present invention includes a member main body made of a metal hollow material having a hollow portion, and a filler filled in the hollow portion. Since the filler is made of a woody material, it has good shock absorbing properties and is lightweight.

Further, when the direction of the fibers in the filler is substantially parallel to the direction of the impact load in a state where the filler is filled in the hollow portion, the filler has extremely good shock absorption characteristics. Become.

In addition, when the wooden material is balsa wood, it is extremely light.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing an impact absorbing member according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a member main body and a filler of the shock absorbing member.

FIG. 3 is a diagram showing a stress-volume distortion curve.

FIG. 4 is a plan view showing a case where the impact absorbing member is used for a crash box of a front bumper of an automobile.

FIG. 5 is a perspective view of the front bumper.

FIG. 6 is a sectional view taken along line VI-VI in FIG. 5;

FIG. 7 is a diagram showing a load-displacement curve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Shock absorbing member 10 ... Member body 12 ... Hollow part 20 ... Filling material 21 ... Wood piece 30 ... Car body 31 ... Bumper reinforcement 32 ... Side member 33 ... Crash box (shock absorbing member) b ... Impact load B ... Fiber direction

Claims (3)

[Claims] A metal hollow material (1) having a hollow portion (12).
An impact absorbing member (1) including a member body (10) made of 1) and a filler (20) filled in the hollow portion, wherein the filler (20) is made of a wood material. A shock absorbing member characterized by the above-mentioned. 2. The impact according to claim 1, wherein the direction of the fibers in the filler is substantially parallel to the direction of the impact load when the hollow portion is filled with the filler. Absorbing member. 3. The wooden material is balsa wood.
Or the shock absorbing member according to 2.