JP2003212069A - Bumper device for automobile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To interpose a shock energy absorbent made of a foamed resin material between a bumper cover and a bumper reinforcement for the purpose of restraining a shock force (load) at the early stage of collision of a vehicle and a passenger low, and reducing the leg disability of the passenger, while a material with high rigidity and high foaming density is required to absorb much more shock energy, resulting in the increase of the remainder of the uncrushed foamed material and the rapid reduction of energy absorbing ability, which is not preferable because the width of the shock energy absorbent is made large and the bumper is enlarged. <P>SOLUTION: A bumper reinforcement (2) and a shock energy absorbent (3) are composed of hollow protrusion molding materials of aluminum alloy materials. The shock energy absorbing material (3) is formed into a pentagonal or parallelogram shape with a hollow cross section, and has a flat load receiving face part (6) on its front face. When the shock energy absorbent receives a shock, it is deformed like a pantograph, so that the remainder of the uncrushed material is less, and the shock energy absorbing ability is high. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bumper device for an automobile which is effective for protecting pedestrians.

[0002]

2. Description of the Related Art A bumper device for an automobile includes a bumper inhose supported on a vehicle body, an impact energy absorber held by the bumper inhose and made of an elastic material such as urethane foam, and a bumper inhose. And an impact energy absorber, the structure of which is disclosed in JP-A-11-208.
No. 389 is disclosed.

The impact energy absorber has a function of absorbing collision energy at the time of collision with a wall, a vehicle, etc., and the impact energy absorber is compressed and deformed at the time of collision with a pedestrian,
It needs a function to absorb collision energy. The impact energy absorber, when a moving vehicle comes into contact with a pedestrian, absorbs the energy at the time of contact and protects the legs of the pedestrian. That is, an impact energy absorber made of urethane foam or the like is indispensable for suppressing the impact force (load) at the initial stage of collision (or contact) between an automobile and a pedestrian and reducing obstacles to the pedestrian's legs.

The impact energy (load) at the initial stage of a collision is absorbed by the collision energy of a car and a pedestrian at the time of collision or collision being absorbed more.
It is said that an impact energy absorber made of a foam having a high rigidity and a high foaming density is preferable in order to keep the value low.

[0005]

The problem with the impact energy absorber made of a foam having a high rigidity and a high foaming density is the uncrushed residue of the foam. The foam of the known example is obtained by deforming polypropylene (PP) into a porous shape. However, when an impact is applied, the porous portion of the pores is crushed and a crushed residue as a completely dense compressed body appears. The uncrushed portion is a compressed body which is about 1/3 of the volume of the foam and which is completely dense or lacks in high-density elasticity and does not have an impact energy absorbing function.

In recent years, due to the need for improving the collision safety of automobiles, an impact energy absorber that absorbs more impact energy with a lower impact force (load) has been required as compared with the conventional one. The thickness of the impact energy absorber (thickness in the load direction) increases because the uncrushed residue of the foam becomes even larger when trying to satisfy the requirement by using
It becomes necessary to increase the value. This increases the size between the bumper cover and the bumper reinforcement and increases the minimum turning radius of the vehicle and adversely affects the vehicle design.

Therefore, it is an object of the present invention to solve the above-mentioned problems of the prior art.

[0008]

In order to solve the above-mentioned problems, the present invention provides a hollow impact energy absorber made of an aluminum alloy. The impact energy absorber made of an aluminum alloy has a crushing residue of about 10% or less when it is impacted, and the impact energy absorption efficiency is extremely high. This is a small thickness (small space)
Thus, it is possible to suppress the impact force at the initial stage of contact between a running vehicle and a pedestrian at the same time and increase the impact energy absorption amount.

According to the present invention, the bumper impinge hose extending in the vehicle width direction of the automobile and the hollow impact energy absorber are arranged so that when the load is applied, the impact energy absorber precedes the bumper impose hose. A bumper device for an automobile is provided which is characterized by being deformed. Preferably, the yield load of the impact energy absorber is smaller than the yield load of the bumper lining hose, and the deformation amount of the impact energy absorber at the initial stage when receiving the load is larger than the deformation amount of the bumper lining hose.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION A bumper device 1 for an automobile comprises a bumper lining hose 2 made of an extruded aluminum alloy material.
And at least the impact energy absorber 3 is included. In the example shown in FIG. 1, a bumper lining hose 2 having a length corresponding to the vehicle width joins a hollow main body 4 having a rectangular cross section and opposing front and rear wall portions, and a connecting wall portion extending horizontally in the vehicle width direction. It consists of 5.

A hollow impact energy absorber 3 having a hexagonal cross section and having a common rear wall portion integrally with the front wall portion of the hollow body 4 is joined to the hollow body 4. The hollow impact energy absorber 3 has a flat load receiving surface portion 6 having substantially the same height as the hollow body 4, and its upper and lower portions are formed in a mountain shape and a valley shape. When the collision load acts on the load receiving surface portion 6, the upper and lower portions 7 and 8 of the inclined outer wall surface are deformed so as to approach each other in a pantograph shape and efficiently absorb impact energy.

The example shown in FIG. 2 is a bumper inhose 9 comprising a hollow main body 4 having the same rectangular cross section as that of the bumper inhose 2 shown in FIG. 1 and a connecting wall portion 5, and impact energy absorption having a hexagonal cross section. It consists of the body 10. The hollow impact energy absorber 10 includes a rear wall portion shared by a part of the front wall portion 11 of the hollow main body 4, a flat load receiving surface portion 12 facing the rear wall portion apart from each other, and a mountain shape having a substantially triangular cross section. And valley top and bottom 13,
14 and. The load receiving surface portion 12 and the rear wall portion have substantially the same height, which is considerably shorter than that in the example of FIG. In other words, the upper and lower parts of the triangular mountain shape and valley shape 13,
The size of 14 is larger than that of the example of FIG.

In the example shown in FIG. 2, the upper and lower portions of the mountain shape and the valley shape 1
This is advantageous in that the deformation amounts of 3 and 14 are large and elastic deformation of this portion is possible even in the case of a light collision with a pedestrian. The rear wall of the impact energy absorber 10 is the connecting wall 5
The shape extends above and below.

The example shown in FIG. 3 is a bumper inhose 15 having the same shape as the bumper inhose 2, 9 shown in FIGS. 1 and 2.
A hollow impact energy absorber 16 having a parallelogram cross section
It is a combination of. The load receiving surface portion 17 as a flat front wall portion of the impact energy absorber 16 faces the upper half of the front wall portion 11 of the hollow body 4 with a space therebetween, and the rear wall portion thereof is common to the front wall portion 11 of the hollow body 4. . Opposite hypotenuse wall portion 18,
When the load is applied, 19 is deformed so as to fall toward the front wall portion 11 of the hollow main body 4 and efficiently absorbs impact energy.

In the illustrated example, the hollow bumper reinforcements 2, 9 and 15 and the hollow impact energy absorbers 3 and 1 are used.
Although 0 and 16 were extruded integrally, they may be separately formed and fixed by rivets or welding. Bumper in-horse 2,9,15 and impact energy absorber 3,
The extruded profile forming 10 and 16 is 6000 series, 700
It consists of a 0 series aluminum alloy.

As is apparent from the illustrated example, the aluminum alloy material occupies a small proportion of the total area of the cross section of the impact energy absorber, and is capable of pantograph-like deformation. Ductility characteristics of the slab are added, there is little crushing residue, it absorbs efficiently under a prescribed allowable load or less, and it absorbs much impact energy even if the thickness of the impact energy absorber (thickness in the load direction) is small. It is possible to reduce the impact force at the initial stage of contact with the pedestrian and reduce the pedestrian's leg injury. Furthermore, the use of extruded profiles made of aluminum alloy material according to the invention
It is possible to reduce the mounting space of the absorber for absorbing the same energy as compared with the conventional example using the foamed resin material.

Next, the results of a load test of an example of the present invention that supports the above-described effects of the present invention will be described. The bumper device used as the specimen had the cross-sectional shape shown in FIG.
Made of 000 series aluminum alloy material, each dimension shown in FIG. 4 has a height (H ₁ ) = 170 mm and a height (H ₂ ) = 10.
0 mm, width (W ₁ ) = 45 mm, width (W ₂ ) = 40 mm, wall thickness (T ₁ ) = 1.4 mm, wall thickness (T ₂ ) = 2 mm, length (L ₁ ) = 1200 mm (see FIG. 5) ). The thickness of the bumper lining hose 2, that is, the wall thickness is unified by T ₂ ,
The plate thickness, that is, the wall thickness of the impact energy absorber 3 is unified as T ₁ , and the angle α of the upper and lower portions is 75 ° and R is 10 mm. As a comparative example, a shock energy absorber was obtained by molding a foamed product of polypropylene resin having a foaming ratio of 20 times into a cross-sectional shape having a height of 170 mm and a width of 80 mm. However, it has a solid shape. Other dimensions and bumper in horse 2
Was molded in the same manner as in the example of FIG.

Both ends of a specimen 20 having a length (L1) of 1200 mm are supported, and an iron pipe 21 of 70φ is provided at the center of the specimen 20.
A static compression load of 0 mm / min was applied, and its displacement and energy absorption amount were measured. The result is shown in FIG. 7. Iron pipe 2
Assuming that 1 is a pedestrian, the maximum allowable load is 8kN
Then, the required energy absorption amount was set to 200J. The load-displacement diagram shown by the solid line is for the example of the present invention, and the displacement is 42 mm when the load reaches the allowable maximum load of 8 kN.
And the energy absorption amount is 200J. The crushing residue at this time is 3 mm. On the other hand, in the comparative example using the foam, the displacement when the load reaches the maximum allowable load of 8 kN is 65 mm, and the energy absorption amount is 2
It is 00J, but the uncrushed portion at this time is 15 mm. That is, in the comparative example, the displacement required to obtain the same energy absorption amount as that of the example of the present invention is 65 mm or less under the allowable maximum load.
In addition, a crushing residual of 15 mm is generated. In other words, the thickness of the impact energy absorber required to obtain the required energy absorption amount of 200 J (thickness in the load direction) is 45 mm in the example of the present invention, while 8 in the comparative example.
Indicates 0 mm. Further, by using a foam having higher rigidity and higher foaming density, it is possible to obtain the required energy absorption amount at about 42 mm which is a displacement equivalent to that of the example of the present invention. Increase to over 30 mm.

FIG. 6 shows the deformation of the test piece by a dotted line. When a load is applied, the load receiving surface portion 6 approaches the front wall portion side of the hollow body 4 and the angle α between the upper and lower portions 7 and 8 is reduced. Eventually, the load receiving surface portion 6 will overlap the front wall portion of the hollow body 4. Such deformation of the impact energy absorber is called pantograph-like deformation. As is clear from FIG. 6, the amount of deformation of the bumper reinforcement is smaller than the amount of deformation of the impact energy absorber.

In the illustrated example, the impact energy absorber and the bumper lining hose are integrally formed by extrusion, but they may be formed separately. In this case, for example, the impact energy absorber can be formed of an aluminum alloy, a synthetic resin, or an iron-based metal (steel material or the like), and the bumper lining hose can be formed of an iron-based metal (steel material or the like).

[Brief description of drawings]

FIG. 1 is a perspective view of an automobile bumper device according to an example of the present invention.

FIG. 2 is a sectional view of a second embodiment of the present invention.

FIG. 3 is a sectional view of a third embodiment of the present invention.

FIG. 4 is a sectional view of a test piece.

FIG. 5 is a front view of the test apparatus.

FIG. 6 is a side view showing a deformed state of the test piece.

FIG. 7 is a graph showing a relationship between a load, a displacement amount, and absorbed energy.

[Explanation of symbols]

1 Car bumper device 2,9,15 Bumper In Horse 3,10,16 Impact energy absorber 4 hollow body 5 connecting wall 7,8,13,14 Upper and lower parts 6,12,17 Load receiving surface 18,19 Opposite hypotenuse wall

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Issei Mori             Aichi, 2-chome, Asahi-cho, Kariya city, Aichi prefecture             Within Seiki Co., Ltd. (72) Inventor Shinichi Haneda             Aichi, 2-chome, Asahi-cho, Kariya city, Aichi prefecture             Within Seiki Co., Ltd. (72) Inventor Kazunari Azuchi             3 Aishi, 12 E, Nagure, Shinminato City, Toyama Prefecture             Light Metal Co., Ltd. (72) Inventor Taku Matsutani             3 Aishi, 12 E, Nagure, Shinminato City, Toyama Prefecture             Light Metal Co., Ltd. (72) Inventor Kyoichi Kita             3 Aishi, 12 E, Nagure, Shinminato City, Toyama Prefecture             Light Metal Co., Ltd.

Claims (5)

[Claims] 1. A bumper impinge hose extending in the vehicle width direction of an automobile and a hollow impact energy absorber, wherein the impact energy absorber is deformed before the bumper impose when a load is applied. Characteristic automobile bumper device. 2. The yield load of the impact energy absorber is smaller than the yield load of the bumper inhose, and the deformation amount of the impact energy absorber at the initial stage when the load is applied is larger than the deformation amount of the bumper inhose. The automobile bumper device according to claim 1. 3. The bumper device for an automobile according to claim 2, wherein the bumper inhose has a connecting wall portion connecting the front and rear wall portions thereof and extending in a direction orthogonal to the load receiving surface portion of the impact energy absorber. 4. The bumper device for an automobile according to claim 2, wherein the impact energy absorber has a mountain-shaped and valley-shaped upper and lower wall portions between the load receiving surface portion and the rear wall portion. 5. The bumper lining hose and the impact energy absorber are made of one extruded profile, the bumper lining hose has a rectangular cross section, and the impact energy absorber has a hexagonal or parallelogram cross section. The rear wall of the energy absorber is shared with a part of the front wall of the bumper inhose, and the flat load bearing part of the impact energy absorber must face the front wall of the bumper inhose. The automobile bumper device according to any one of claims 2 to 4, which is characterized in that.