JPH10175485A - Shock absorbing bumper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease damage by improving energy absorbability at the time of bumper central collision and/or barrier collision. SOLUTION: This bumper comprises an aluminum shape material-made bumper R/F2 mounted in the front or rear of an automobile and a foaming resin-made form material 3. Here, a multiplying factor of the foaming material is different in a bumper central part and a mounting part periphery, a compressing load Fa of a foaming material 3a in the bumper central part and a bending load Pa of a bumper R/F are in a relation of a formula 0.53>Fa/Pa>0.23, a compressing load Fb of a foaming material 3b in the mounting part periphery of the bumper and a collapsing load Pb of the bumper R/F are in a relation of a formula 0.25>Fb/Pb>0.1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle bumper system for absorbing collision energy.

[0002]

2. Description of the Related Art As shown in FIG. 13, a bumper 1 is disposed at the front and rear of an automobile. The bumper 1 is deformed when an impact is applied to an obstacle to reduce the impact, thereby reducing damage to occupants and the vehicle body. A bumper R / F2 whose central portion has a uniform cross section in the length direction and is formed linearly.
Are attached to the side members 4 directly or via stays.

[0003] Incidentally, as a form at the time of collision, FIG.
As shown in FIG. 15, the entire surface of the vehicle collides with the obstacle 5 (wall surface) (hereinafter referred to as barrier collision), and as shown in FIG. Collision (hereinafter referred to as central collision)
The bumper 1 serves to reduce the damage to the vehicle when these collisions occur at a relatively low speed.

In recent years, in order to improve the collision safety of automobiles, a bumper 1 composed of a bumper R / F 2 and a foam material 3 having a substantially uniform expansion ratio has been used. To cope with this, a bumper R / F made of an extruded aluminum member is used.

Here, the functions of the foam material 3 and the bumper R / F2 at the time of center collision and at the time of barrier collision will be described. When the vehicle collides at the center, the bumper R / F is in a deformation mode in which the bumper R / F is bent at the center, and the load generated at this time is relatively small. Therefore, the foam material around the central portion is desired to have a property of compressively deforming with a relatively small load and absorbing collision energy. On the other hand, when the vehicle collides with the barrier, the bumper R / F is in a deformation mode in which the bumper R / F is crushed at the mounting portion, and the load generated at this time is very large. Therefore, it is desired that the foam material around the mounting portion be compressed and deformed by a relatively large load and have a large energy absorption.

However, it has been difficult to construct a bumper having these two characteristics from a bumper R / F made of an extruded aluminum material and a foam material having a substantially uniform expansion ratio and thickness. To alleviate this problem, foam materials having partially different expansion ratios may be combined (actually
-25968), a method of partially changing the expansion ratio of a foam material by continuous integral molding (JP-A-4-215).
544), the balance between the compression load of the foam material around the center of the bumper and the bending load of the bumper R / F, and the compression load of the foam material around the mounting portion and the crushing of the bumper R / F. When the load balance is not good, the bumper R / F and the foam material do not function well, so that the damage to the vehicle body cannot be reduced.

That is, if the compression load of the foam material around the center is too small compared to the bending load of the bumper R / F, the foam material cannot sufficiently absorb the collision energy at the time of the central collision. If the size is too large, the bumper R / F bends and deforms before the foam material is crushed, so that the damage is increased. On the other hand, if the compression load of the foam material around the mounting portion is too small compared to the crushing load of the bumper, the energy absorbed when the foam material undergoes compressive deformation at the time of collision is not sufficient, and If the compression load of the foam material is too large compared to the crushing load of the bumper, the mounting portion of the bumper R / F is crushed before the foam material is compressed and deformed in the event of a collision, and the problem of increased damage still remains. Existed.

[0008]

As described above, the bumper composed of the bumper R / F made of an extruded aluminum material and the foam material has a crushing load and a bending load of the bumper R / F, and a foam material at the center of the bumper. Unless the compressive load and the compressive load of the foam material in the vicinity of the bumper mounting portion are properly applied, it is difficult to reduce damage at the time of a center collision and / or a barrier collision. Therefore, the present invention provides the energy at the time of the center collision and / or the barrier collision of the bumper by appropriately applying the crushing load and the bending load of the bumper R / F and the compressive load of the foam material around the mounting portion and the central portion. An object of the present invention is to provide a shock-absorbing bumper capable of improving absorbability and reducing damage.

[0009]

According to the present invention, there is provided a shock-absorbing bumper according to the present invention, wherein a bumper made of an aluminum-shaped material R / F and a foam material made of a foamed resin is attached to a front or rear of an automobile. The center of the bumper R / F and the periphery of the mounting portion of the bumper R / F are made of foam materials having different expansion ratios, and the compression load Fa of the foam material at the center is the bending load Pa of the bumper R / F and the following formula. And the compression load Fb of the foam material around the mounting portion of the bumper has a relationship with the crushing load Pb of the bumper R / F according to the following equation. 0.53> Fa / Pa> 0.23 ... 0.25> Fb / Pb> 0.1 ...

FIG. 1 schematically shows the above-mentioned bumper of the present invention. The bumper according to the present invention has a uniform rectangular cross-section (H ×
A foam material 3a at the center and a foam material 3b around the mounting portion are attached to the front surface of a bumper R / F2 forming B), and the bumper R / F2 is attached to the vehicle body via a side member 4. And in the bumper of the present invention,
The compression load Fa of the foam material at the center and the compression load Fb of the foam material around the mounting portion are 50% of the respective foam materials.
It is defined as% compressive strength multiplied by area. The bending load Pa of the bumper R / F is, as shown in FIG. 2, a cylindrical pressing jig having a diameter of 100 mm at the center of the bumper R / F horizontally supported by a span L (a space between both side members). Defined as a three-point bending load Pa obtained by pressing
The crushing load Pb of the bumper R / F is, as shown in FIG.
Place the bumper R / F on the substrate corresponding to the barrier, which when the crushing load obtained by pressing was P ₁ by a jig having a width S, which corresponds to the side members, and Pb = 2 × P ₁ Defined.

Further, in the bumper of the present invention,
The left and right width of the side member 4 is S, and the bumper R / F2
, The length in the vehicle width direction of each foam material 3b around the mounting portion is (S + 2H) to (S + 4).
It is preferable to set the range of H), and to set the range therebetween as the foam material 3a at the center. This is because if the length of the foam material 3a in the vehicle width direction of the mounting portion is smaller than (S + 2H) (the foam material 3a in the center becomes longer by that amount), the energy absorbed by the foam material at the time of barrier impact is reduced. Because it becomes smaller,
There is a problem that the amount of crushing deformation of the bumper R / F becomes large, and when it is larger than (S + 4H) (the foam material 3a at the center becomes shorter correspondingly), the foam material is compressed and deformed at the time of central collision. This is because it is difficult to cause a problem that bending deformation of the bumper R / F becomes large.

According to the above construction, the foam material sufficiently absorbs the collision energy before the bumper R / F bends and deforms at the time of a central collision, and the foam material absorbs the collision energy even at the time of a barrier collision. When the foam material is compressed and deformed, the collision energy is sufficiently absorbed, so that the deformation of the bumper R / F can be reduced and damage to the vehicle can be prevented.

The above description has been made on the assumption that the shock absorbing bumper according to the present invention satisfies both of the above conditions. However, a shock absorbing bumper that satisfies only one of the above conditions is also available. It is included in the scope of the present invention. When the above condition is satisfied, a shock absorbing bumper having improved energy absorption at the time of a central collision can be obtained. On the other hand, when the above condition is satisfied, a shock absorbing bumper having improved energy absorbing at the time of a barrier collision can be obtained. Can be obtained.

The bumper described above is composed of a bumper R / F, a foam material at a central portion, and a foam material around a mounting portion having a different expansion ratio from the bumper R / F. The present invention is also applicable to a bumper having a foamed resin foam material having a substantially uniform expansion ratio at any portion. That is, especially when it is important to improve the energy absorbing property and reduce the damage at the time of the central collision, the shock absorbing bumper according to the present invention has the bumper R /
In a bumper made of a foamed material made of a foamed resin in which the expansion ratio is almost uniform in any part, the compression load Fa of the foam material in the center of the bumper is in the relationship with the bending load Pa of the bumper R / F according to the above formula. It is characterized by. on the other hand,
In particular, when it is important to improve the energy absorption at the time of barrier collision and to reduce the damage, the shock absorbing bumper according to the present invention provides a substantially uniform foam at any bumper R / F and foaming ratio. A bumper made of a resin foam material is characterized in that the compression load Fb of the foam material around the mounting portion of the bumper is in the relationship of the above formula with the crushing load Pb of the bumper R / F.

In the case of these two inventions, the foam material around the mounting portion of the bumper has a length in the vehicle width direction of (S + 2H).
To (S + 4H), and the central foam material of the bumper is defined as the remaining central foam material. In other words, the foam material (central portion or periphery of the mounting portion) within this range satisfies either of the above formulas or the formulas or both in some cases. Bumper R /
The bending load Pa of F and the crushing load Pb of the bumper R / F are defined in the same manner as in the above invention.

In the present invention, a foam material obtained by foaming foamable beads of, for example, polypropylene in a mold is preferable. Further, as the aluminum profile used for the bumper R / F, for example, an extruded profile of a 6000 series alloy is suitable, and as the cross-sectional shape, a rectangular cross-sectional shape such as a rice shape, a Japanese shape, an eye shape, Mouth shape and the like (see FIGS. 4 to 7) can be cited, each of which is characterized by a bending load Pa and a crushing load Pb. Among them, particularly in a barrier collision, a field shape, a sun shape, and an eye shape having ribs perpendicular to the collision surface are preferable to the mouth shape.

[0017]

【Example】

Example 1 A side member 4 was attached to a bumper R / F2 made of an aluminum alloy shaped member (having a cross section in the shape of a rectangle) having dimensions (unit: mm) shown in FIG. The bending load of this aluminum alloy profile was Pa = 1200 kgf, and the crushing load was Pb = 9500 kgf. First, in order to find a suitable relationship between the bending load of the bumper R / F and the compressive load of the foam material at the center for the center collision, the bumper R
A foam having various compression loads (adjusted by changing the expansion ratio variously) was attached to the center of the front surface of the / F to form a test body, which was attached to the bogie 6 and a collision test was performed. The dimensions of the test piece are as shown in FIG. The collision jig 8 (pendulum) used in the central collision test is dimensioned as shown in FIG. 9B so that an actual collision between automobiles can be reproduced, and its weight is 1.2 tons and the weight of the bogie is also 1 .2 tons,
The collision speed was 4 km / h. The result is shown in FIG.

In the case of such a central collision, the bumper R /
When the permanent deformation of F in the load direction is 3.0 mm or more,
The possibility of damage to components mounted on the periphery of the vehicle front is increased. As shown in FIG. 10, the permanent deformation amount of the bumper R / F is 1 mm or less at the minimum when Fa / Pa is about 0.3, and is 3 or less when Fa / Pa is 0.23 or less and 0.53 or more. 0 mm or more, and rapidly increases.

(Embodiment 2) Next, in order to obtain a suitable relationship between the crushing load of the bumper and the compressive strength of the foam material around the mounting portion against the barrier collision, various types of components around the mounting portion of the bumper R / F were determined. A test material was constructed by symmetrically attaching a foam material having a compressive load (adjusted by changing the expansion ratio variously), and this was attached to the bogie 7 to perform a collision test. The dimensions of the test piece are as shown in FIG. The dimensions of the bumper R / F, the bending load Pa and the crushing load Pb are the same as those in the first embodiment. The weight of the trolley 7 used in the collision test was 1.2 tons, and the trolley 7 collided with a fixed wall surface at a speed of 8 km / h. FIG. 12 shows the result.

In the case of a barrier collision, the bumper R / F
If the amount of permanent deformation in the load direction is 10 mm or more, there is a high possibility that the mounted parts and the like around the front of the vehicle may be damaged. As shown in FIG. 12, the permanent deformation amount of the bumper R / F is minimum when Fb / Pb is about 0.2, and
When b is 0.1 or less and 0.25 or more, it becomes 10 mm or more, and rapidly increases. In this embodiment, the foam material at the center was not attached to investigate the effect of the foam material around the attachment portion, but 0.23 <Fa /
Even when a foam material having Pa <0.53 is attached, the compression load of the foam material at the center is sufficiently smaller than the compression load of the foam material around the attachment portion. can get.

According to the above embodiment, a foam material whose compressive load Fa is in a relation of 0.23 <Fa / Pa <0.53 with the bending load Pa of the bumper R / F is formed in the center of the bumper by an aluminum material. And the compression load Fb around the mounting portion of the bumper is smaller than the crushing load Pb of the bumper R / F by 0.1 <Fb.
It can be seen that the energy absorption performance at the time of a center collision and / or a barrier collision can be improved by attaching a foam material satisfying the relationship of /Pb<0.25.

[0022]

According to the present invention, a bumper R / F made of an aluminum profile is combined with a foam material having a different compressive load at the center and around the mounting portion, and the bending load of the bumper R / F and the bumper center are combined. Since the balance between the compressive load of the foam material and / or the crushing load of the bumper R / F and the compressive load of the foam material around the bumper mounting portion is optimized, the foam can be used at the time of a center collision and / or a barrier collision. Since the material is sufficiently compressed and deformed to absorb energy, and then the bumper R / F is deformed, the collision energy can be efficiently absorbed, and damage to the vehicle body at the time of collision can be minimized.

When a foam material having a uniform expansion ratio is used as a whole, the bending load of the bumper R / F and the compression load of the foam material at the center of the bumper, or the bumper R / F
Optimizes the balance between the crushing load of the foam and the compressive load of the foam material around the bumper mounting part, so if it is applied especially when central collision is important or barrier collision is important, the foam material will be sufficient The energy is absorbed by compressive deformation, and then the bumper R / F is deformed, so that the collision energy can be efficiently absorbed.
Damage to the vehicle body during a collision can be minimized.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a structure of a bumper according to the present invention.

FIG. 2 is a diagram illustrating a bending load Pa of a bumper R / F.

FIG. 3 is a diagram illustrating a crushing load Pb of a bumper R / F.

FIG. 4 is a cross-sectional shape (a cross-section in a cross section) of an aluminum material forming a bumper R / F according to the present invention.

FIG. 5 is a cross-sectional shape (day-shaped cross-section) of an aluminum profile constituting the bumper R / F according to the present invention.

FIG. 6 is a cross-sectional shape (a cross-sectional shape) of an aluminum material constituting the bumper R / F according to the present invention.

FIG. 7 is a cross-sectional shape (mouth-shaped cross-section) of an aluminum material forming the bumper R / F according to the present invention.

FIG. 8 is a view showing the structure and dimensions of a test body used in Example 1.

9A is a diagram illustrating a central collision test according to the first embodiment, and FIG. 9B is a diagram illustrating dimensions of the collision jig.

FIG. 10 shows the results of bumper R /
It is a figure which shows the relationship between the permanent deformation amount of F and Fa / Ra.

FIG. 11 is a view showing the structure and dimensions of a test piece used in Example 2.

FIG. 12 is a diagram showing the relationship between the amount of permanent deformation of a bumper R / F and Fb / Rb obtained by a barrier collision test.

FIG. 13 is an explanatory diagram of a mounting state of a bumper.

FIG. 14 is an explanatory diagram of a barrier collision of an automobile.

FIG. 15 is an explanatory diagram of a center collision of an automobile.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bumper 2 Bumper R / F 3 Foam material 3a Foam material at the center of bumper 3b Foam material around bumper mounting part 4 Side member

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kenji Ono 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation

Claims (5)

[Claims] 1. A bumper made of aluminum material and mounted on the front or rear of an automobile (hereinafter referred to as bumper R / F) and a foamed resin foam material having a substantially uniform expansion ratio in any portion. 2. The shock absorbing bumper according to claim 1, wherein the compression load Fa of the foam material at the center of the bumper is in the relationship of the following formula with the bending load Pa of the bumper R / F. 0.53> Fa / Pa> 0.23 ... 2. A bumper made of an aluminum-shaped bumper R / F mounted on a front or a rear of an automobile and a foamed resin foam material having a substantially uniform expansion ratio in any portion. An impact-absorbing bumper, characterized in that the compression load Fb of the material has the following formula with the crushing load Pb of the bumper R / F. 0.25> Fb / Pb> 0.1 ... 3. A bumper made of an aluminum-shaped material bumper R / F and a foamed resin foam material attached to a front or rear of an automobile, wherein a foaming ratio of the foam material differs between a center portion of the bumper and a periphery of the mounting portion. The compressive load Fa of the foam material at the center of the bumper is in the following formula with the bending load Pa of the bumper R / F, and the compressive load Fb of the foam material around the mounting portion of the bumper is as follows: A shock-absorbing bumper characterized by the following formula. 0.53> Fa / Pa> 0.23 ... 0.25> Fb / Pb> 0.1 ... 4. In a bumper made of an aluminum-shaped material bumper R / F and a foamed resin foam material attached to the front or rear of an automobile, the foaming ratio of the foam material differs between the center of the bumper and the periphery of the mounting portion. An impact-absorbing bumper, characterized in that the compression load Fa of the foam material at the center of the bumper is in the following formula with the bending load Pa of the bumper R / F. 0.53> Fa / Pa> 0.23 ... 5. In a bumper made of an aluminum-shaped bumper R / F and a foamed resin foam material attached to a front or rear of an automobile, the foaming ratio of the foam material differs between a center portion of the bumper and a periphery of the mounting portion. The compression load Fb of the foam material around the mounting portion of the bumper is
/ F crushing load Pb and the following equation. 0.25> Fb / Pb> 0.1 ...