JP2004284464A - Automotive bumper device - Google Patents

Abstract

An object of the present invention is to provide a bumper device capable of efficiently absorbing impact energy at a constant load with a small amount of uncrushed foam.
A shock energy absorber (3) is made of a hollow extruded member made of an aluminum alloy material and is partially connected to a bumper hose (2). The impact energy absorber 3 has a hollow hexagonal shape or a parallelogram having a hollow cross section, and the thickness of the load receiving surface portion and the front portion of the upper and lower walls is 1.2 to 3.5 times the thickness of the rear wall portion and the rear portion of the upper and lower walls. When receiving an impact, the load receiving surface 6 is deformed into a pantograph shape, and at the time of collision (or contact) between a car and a pedestrian, the load receiving surface 6 in contact with the human body leg and the front surface around the load receiving surface 6 are connected to the human body leg. The energy is absorbed by bending and deforming backward with the center as the center, the remaining uncrushed is small, and the impact energy can be efficiently absorbed at a constant load.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an automobile bumper device that is effective for protecting pedestrians.
[0002]
[Prior art]
An automobile bumper device includes a bumper-in hose supported on a vehicle body side and an impact energy absorber held by the bumper-in hose and made of an elastic material such as urethane foam. 208389.
[0003]
The impact energy absorber needs to have the function of absorbing the collision energy in addition to the function of absorbing the collision energy in the event of a collision between a wall and a vehicle, as well as compressing and deforming the impact energy absorber in the event of a collision with a pedestrian. I do.
The impact energy absorber absorbs energy at the time of contact between a running automobile and a pedestrian, and protects the pedestrian's leg. 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 the collision (or contact) between the automobile and the pedestrian and reducing the obstacle for the pedestrian.
[0004]
Furthermore, in order to efficiently absorb high collision energy at the time of collision with a vehicle against a wall or a vehicle, and to suppress the impact force (load) at the initial stage of the collision, it is necessary to use a foam having high rigidity and high foam density. Impact energy absorbers are preferred.
[0005]
[Patent Document 1]
JP-A-11-208389 [0006]
[Problems to be solved by the invention]
The problem with an impact energy absorber made of a foam having a high rigidity and a high foam density is that the foam remains uncrushed. 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 the crushed portion as a completely dense compressed body appears. The uncrushed portion is a completely dense or high-density compressed body lacking elasticity, which is about 1/3 of the volume of the foam, and does not have a function of absorbing impact energy.
[0007]
In recent years, impact energy absorbers that absorb more collision energy with a lower impact force (load) have been required in recent years due to the need to improve the collision safety of automobiles. In order to satisfy the requirement, the remaining uncrushed portion of the foam is further increased. Therefore, it is necessary to increase the thickness (thickness in the load direction) of the impact energy absorber.
This increases the dimensions between the bumper cover and the bumper in hose, increasing the minimum turning radius of the vehicle and adversely affecting the design of the vehicle.
[0008]
Therefore, an object of the present invention is to solve the above-described disadvantages of the related art.
[0009]
[Means for Solving the Problems]
SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention comprises a bumper-in hose extending in the width direction of an automobile and a hollow impact energy absorber, and when a load is applied, the impact energy absorber becomes a bumper-in hose. A bumper device for an automobile that deforms earlier than the above, in which a bumper in hose and an impact energy absorber are separately formed, and the thickness of the front portion of the impact energy absorber having a polygonal cross section is smaller than that of the rear portion. Provided is an automobile bumper device having a thickness greater than a wall thickness.
If the thickness is less than 1.2 times, the relationship between the load strokes tends to slightly rise to the right, which is not always preferable. On the other hand, when the thickness exceeds 3.5 times, molding becomes difficult, which is not preferable.
The impact energy absorber made of this aluminum alloy has an uncrushed portion of about 10% or less when subjected to an impact, and the impact energy absorption efficiency is extremely large. Further, the load up to the remaining collapse is substantially constant.
This makes it possible to obtain a stable load with a small thickness (small space) and to suppress the impact force at the initial stage of contact between a running car and a pedestrian, and also to efficiently increase the amount of impact energy absorbed. .
[0010]
ADVANTAGE OF THE INVENTION According to this invention, the bumper in hose which extends in the vehicle width direction of an automobile, and a hollow impact energy absorber, and the impact energy absorber deforms earlier than the bumper in hose when receiving a load A bumper device, wherein a bumper in hose and an impact energy absorber are separately formed, and the front wall thickness of the impact energy absorber having a polygonal cross section is larger than the rear wall thickness. A bumper device is provided.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
The automotive bumper device 1 includes at least a bumper-in hose 2 made of an extruded aluminum alloy material and an impact energy absorber 3 made of an extruded aluminum alloy material.
The example shown in FIG. 1 is a connecting wall portion in which a bumper-in hose 2 having a length equivalent to the vehicle width connects a hollow main body 4 having a rectangular cross section and opposed front and rear wall portions and extends horizontally in the vehicle width direction. 5
The front wall portion 4a of the hollow body 4 and a part 9a of the rear wall portion 9 of the hollow impact energy absorber 3 having a substantially hexagonal cross section are partially joined by rivets or welding.
[0012]
The hollow impact energy absorber 3 has a flat load receiving surface portion 6 extending in the vehicle width direction, and an upper portion thereof has a mountain-shaped upper wall portion 7 including an upper wall front surface portion 7a and an upper wall rear surface portion 7b. The lower portion is formed of a valley-shaped lower wall portion 8 composed of a lower wall front portion 8a and a lower wall rear portion 8b. When a collision load is applied to the load receiving surface 6, the mountain-shaped upper wall 7 and the valley-shaped lower wall 8 form an upper wall front 7 a and an upper wall rear 7 b, a lower wall front 8 a and a lower wall. The rear portions 8b are deformed so as to approach each other in a pantograph shape, and the periphery of the load receiving surface portion 6 in contact with the human leg is bent backward around the human leg to absorb energy.
[0013]
At this time, the rear wall 9 of the impact energy absorber 3 is joined to the hollow main body 4 of the bumper-in hose 2 only at a part 9a only at a part thereof. The load receiving surface portion 6 in contact with the leg portion and the front portion around the load portion are bent backward around the human body leg portion to absorb energy, and the load increase until the remaining portion is collapsed is reduced.
[0014]
Further, the thickness of the load receiving surface portion 6 is set to 2.5 times the thickness of the rear wall portion 9, the upper wall rear surface portion 7b, and the lower wall rear surface portion 8b located behind the load receiving surface portion 6, and the upper wall front surface portion 7a and the lower wall By making the thickness of the front portion 8a 3.5 times the thickness of the rear wall portion 9, the upper wall rear surface portion 7b, and the lower wall rear surface portion 8b, the human leg can be used in the event of a collision (or contact) between a car and a pedestrian. The load receiving surface portion 6 in contact with the portion and the surrounding front portion are bent rearward around the human body leg portion to absorb energy, and the load up to the remaining collapse is substantially constant.
[0015]
The example shown in FIG. 2 is a bumper line hose 10 (same shape as the bumper line hose 2 shown in FIG. 1) made of an extruded aluminum alloy material having a hollow main body 4 having a rectangular cross section and a connecting wall portion 5. The impact energy absorber 11 has a substantially parallelogram-shaped cross section.
The front wall portion 4a of the hollow body 4 and the upper wall rear surface portion 12b, the lower wall rear surface portion 13b of the hollow impact energy absorber 11 having a rhombic cross section, that is, a substantially parallelogram cross section, or a part of a joint portion thereof are bonded. Partially joined by an agent or spot welding. Of course, it may be screwed via another member (not shown).
[0016]
The hollow impact energy absorber 11 has a mountain-shaped upper wall portion 12 composed of an upper wall front portion 12a and an upper wall rear portion 12b, and a valley shape composed of a lower wall front portion 13a and a lower wall rear portion 13b. The lower wall 13 is provided.
When a collision load acts on the apex of the joint 11a between the upper wall front part 12a and the lower wall front part 13a and acts as a load receiving part, the upper wall front part 12a and the upper wall rear part 12b are formed in a substantially hexagonal cross section. The front portion 13a and the rear portion 13b of the lower wall are deformed so as to approach each other in a pantograph shape, and the energy is efficiently absorbed by bending deformation in the vertical direction of the vehicle with the human leg as a center axis.
[0017]
Furthermore, by making the thickness of the upper wall front part 12a and the lower wall front part 13a 1.2 to 3.5 times the thickness of the upper wall rear part 12b and the lower wall rear part 13b, the distance between the car and the pedestrian is reduced. At the time of collision (or contact), the load receiving surface portion 6 in contact with the human leg and the surrounding front portion are bent rearward with the human leg as a central axis to absorb energy, and the load until the remaining collapse is substantially constant. It becomes.
[0018]
In the illustrated example, a part of the hollow impact energy absorber on the rear wall side is partially connected to the bumper-in hose by rivets, welding, or an adhesive. The surface may be partially joined with a rivet or an adhesive.
In addition, the bumper in hose and the shock energy absorber are formed from an extruded aluminum alloy material, but the bumper in hoses 2 and 10 are formed from an aluminum alloy or iron-based metal (steel material, etc.). The impact energy absorbers 3 and 11 may be formed of an aluminum alloy, a synthetic resin, or an iron-based metal (such as a steel material).
[0019]
As is clear from the illustrated example, the ratio of the aluminum alloy material to the total area of the cross section of the impact energy absorber is small, and the pantograph-like deformation is enabled. Effectively absorbs impact energy with a constant load less than the value, and absorbs a large amount of impact energy even if the thickness of the impact energy absorber (thickness in the load direction) is small. Can reduce pedestrian leg disorders.
Further, the use of an extruded profile made of an aluminum alloy material according to the present invention is disclosed in a conventional example using a foamed resin material and an automobile bumper device which was filed by the applicant of the present invention and which was not disclosed at the time of this application (Japanese Patent Application 2002 In comparison with (017138), the mounting space for the absorber for absorbing the same energy can be reduced.
[0020]
Next, load test results of an example of the present invention supporting the effects of the present invention will be described. The bumper device used as the specimen has the cross-sectional shape shown in FIG. 3. The bumper in hose 2 is made of extruded aluminum alloy material of 7000 series, and the impact energy absorber 3 is made of aluminum alloy of 6000 series. It consists of extruded material.
The front wall portion 4a of the bumper-in hose 2 and the rear wall portion 9 of the impact energy absorber 3 are partially joined by welding at a position (see FIG. 4) at a length (L ₂ ) = 1100 mm (see FIG. 4).
[0021]
The impact energy absorber 3 shown in FIG. 3 has a height (H ₁ ) = 100 mm, a width (W ₁ ) = 45 mm, a thickness (T ₁ ) = 2.5 mm, a thickness (T ₂ ) = 1 mm, and upper and lower portions. Is (α ₁ ) = 65 °, and the bumper in hose 2 has a width (W ₂ ) = 40 mm and a wall thickness (T ₃ ) = 2 mm.
Further, the height (H ₁ ) = 100 mm and the length (L ₁ ) = 1200 mm (see FIG. 4) of the bumper in hose 2 and the impact energy absorber 3 are the same.
[0022]
As Comparative Example 1, a foam having a foaming ratio of 15 times using a polypropylene resin and having a height of 100 mm and a width of 80 mm and having the same cross-sectional shape as the shock energy absorber of FIG. 3 was used as the shock energy absorber. . However, it has a solid shape. The bumper in hose 2 was formed in the same manner as in the example of FIG.
[0023]
Please refer to FIG. Both ends of the specimen 20 having a length (L ₁ ) of 1200 mm were supported, and a static compressive load F of 30 mm / min was applied to the center of the specimen 20 through an iron pipe 21 of 70φ, and the displacement and energy absorption were measured. FIG. 6 shows the result.
Assuming that the iron pipe 21 is a pedestrian, the allowable maximum load was set to 6 kN, and the necessary energy absorption was set to 200 J.
The load-displacement diagram shown by the solid line is that of the example of the present invention. When the load reaches the allowable maximum load of 6 kN, the displacement is 40 mm, and the energy absorption is 200 J. At this time, the remaining uncrushed portion is 5 mm.
[0024]
On the other hand, in Comparative Example 1 using the foam, the displacement was 60 mm when the load reached the allowable maximum load of 6 kN, the energy absorption was 200 J, and the uncrushed portion at this time was 20 mm.
That is, in Comparative Example 1, the displacement required to obtain the same amount of energy absorption as that of the present invention example below the allowable maximum load is 60 mm, and 20 mm remains uncrushed. In other words, the thickness (thickness in the load direction) of the impact energy absorber required to obtain the required energy absorption of 200 J is 45 mm in the example of the present invention and 80 mm in the comparative example. Is shown.
Further, by using a foam having a higher rigidity and a higher foam density, it is possible to obtain the required energy absorption at about 40 mm, which is the same displacement as that of the example of the present invention. Increase to 30mm or more.
[0025]
FIG. 5 shows the deformation of the specimen by a dotted line. When a load is applied, the angle α of the upper and lower walls 7, 8 is reduced while the load receiving surface 6 approaches the front wall 4a of the hollow body 4. Eventually, the load receiving surface 6 overlaps the front wall 4 a of the hollow body 4. Such a deformation of the impact energy absorber is called a pantograph-like deformation.
As is clear from FIG. 5, the deformation amount of the bumper in hose 2 is smaller than the deformation amount of the impact energy absorber 3.
[0026]
In the illustrated example, a part of the rear wall portion of the hollow impact energy absorber is partially connected to the bumper-in hose by welding or the like, but is located in front of the load receiving surface of the impact energy absorber and the impact energy absorber. May be partially connected to a bumper cover or the like using a rivet or an adhesive.
In addition, the bumper in hose and the shock energy absorber are formed from an extruded aluminum alloy material. The bumper in hose is formed from an aluminum alloy or iron-based metal (steel material, etc.) to absorb the shock energy. The body can be formed of an aluminum alloy, a synthetic resin, or an iron-based metal (such as a steel material).
[Brief description of the drawings]
FIG. 1 is a perspective view of an example of an automobile bumper device 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 specimen.
FIG. 4 is a front view of the test apparatus.
FIG. 5 is a side view showing a deformed state of a specimen.
FIG. 6 is a graph showing a relationship between a load, a displacement amount, and absorbed energy.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Bumper apparatus 2 for automobiles 2, 10 Bumper in hose 3, 11 Impact energy absorber 4 Hollow main body 4a Front wall of hollow main body 5 Connecting wall 6 Load receiving surface 7, 12 Upper wall 7a, 12a Upper wall front 7b, 12b Upper wall rear surface 8, 13 Lower wall 8a, 13a Lower wall front 8b, 13b Lower wall rear 9 Rear wall 9a Partially joined rear wall

Claims (6)

A bumper device for an automobile, comprising a bumper in hose extending in the width direction of an automobile and a hollow impact energy absorber, wherein the impact energy absorber deforms earlier than the bumper in hose when receiving a load, A bumper device for an automobile, in which a bumper in hose and an impact energy absorber are separately formed, and the thickness of the front portion of the impact energy absorber having a polygonal cross section is larger than the thickness of the rear portion. 2. The bumper device for an automobile according to claim 1, wherein the impact energy absorber has a substantially hexagonal cross section or a substantially rhombic cross section, and the thickness of the front surface is 1.2 to 3.5 times the thickness of the rear surface. An impact energy absorber having a substantially hexagonal cross section has a load receiving surface extending in the vehicle width direction and having a flat load receiving surface, and a flat rear wall positioned behind and behind the load receiving surface. 3. The vehicle bumper device according to claim 2, wherein the thickness of the surface portion is two to three times the thickness of the rear wall portion. 4. The automobile bumper device according to claim 3, wherein the thickness of the front wall of the upper wall and the front of the lower wall following the load receiving surface is 3.5 times the thickness of the rear wall. 3. The shock energy absorber having a substantially rhombic cross section, wherein the thickness of the front wall of the upper wall and the front of the lower wall is two to three times the thickness of the rear wall of the upper wall and the rear wall of the lower wall. Automotive bumper device. The vehicle bumper device according to claim 4 or 5, wherein the impact energy absorber comprises an extruded aluminum alloy material.

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