JPH04287741A - Energy absorber of bumper for vehicle - Google Patents

Abstract

PURPOSE:To improve the energy absorbing performance by providing notches at specific ratios in the height direction and width direction of an outside wall on the lattice face of an energy absorber with a resin lattice-shaped structure fitted to the reinforcement of a bumper. CONSTITUTION:Notches 6 are provided at 20-90% in the height direction (vehicle body direction) of an outside wall and at 10-50% in the width direction (vertical direction) on the lattice face applied with the external force of an energy absorber 1. Bending moment is applied to the energy absorber 1 by the notches 6 and the deformation (rolling) of a reinforcement 2. Compression buckling and bending deformation are generated on the energy absorber 1, and the energy absorbing characteristic is limited near the vehicle body limit load and is prevented from exceeding it.

Description

[Detailed description of the invention]

0001

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

0002

2. Description of the Related Art A vehicle bumper is provided to prevent damage to the vehicle in the event of a collision, and as shown in FIG. The reinforcements 33 are attached to the vehicle body in this order. In the event of a collision, the energy absorber 32 is crushed first, and then the reinforcement 33 is crushed.
The structure is designed to deform and absorb energy sequentially within a range that does not exceed the limit strength of the vehicle body.

However, the conventional vehicle bumper shown in FIG. 8 above exhibits energy absorption characteristics as shown by the solid line in FIG.
There was a gap. In other words, the ideal energy absorption characteristic rises rapidly at the beginning of a collision, becomes flat at the vehicle body limit load (A in the figure), and the amount of front side deformation (the amount of deformation of the energy absorber 32) also decreases to the allowable amount of deformation (B in the figure). ). In addition, in this case, as shown in Fig. 10, the amount of rearward deformation (the amount of deformation of the reinforcement 33 in the direction of the vehicle body) also remains within the reinforcement damage level (within the allowable deformation amount D of the reinforcement). It is necessary to be present. Note that C in FIG. 10 is the vehicle body limit load. In contrast, with conventional vehicle bumpers, there is little rise in the initial stage of a collision, so the amount of energy absorption, which is an integral amount based on the deformation of the load, is reduced, and in order to ensure this amount of absorption, the energy absorber must be made larger. I had no choice. This creates design constraints and
It had drawbacks such as being expensive and increasing weight.

In order to improve the above-mentioned drawbacks of the conventional energy absorber, there has been a vehicle bumper using an energy absorber 32 having a grid-like structure made of resin, as shown in FIG. In addition, in this figure, the left side shows before deformation, and the right side shows after deformation.

[0005]

[Problems to be Solved by the Invention] However, the above-mentioned conventional resin lattice structure energy absorber exhibits a load-deformation pattern (solid line) as shown in FIGS. 12 and 13. As shown in these figures, the energy absorption characteristics rise rapidly in the early stages of a collision, but during the process of absorbing impact energy, the vehicle body's limit load may be exceeded, causing the reinforcement to break or the vehicle side members to break. There was a risk that the

[0006]

[Means for Solving the Problems] The present invention has been made in view of the above circumstances, and provides an energy absorber having a resin lattice structure attached to a resin or metal reinforcement of a vehicle bumper. This invention provides an energy absorber for a vehicle bumper, in which a cutout is provided in the lattice surface on which external force acts on the outer wall by 20 to 90% in the height direction and 10 to 50% in the width direction of the lattice surface. be.

[0007]

[Operation] In the present invention, the energy absorption characteristics of the energy absorber rise rapidly at the initial stage of a collision. Furthermore, since a portion of the energy absorber having a resin lattice structure is cut out, a bending moment is generated in the energy absorber in combination with the deformation of the reinforcement. This causes not only compression buckling but also bending deformation in the energy absorber. For this reason, the energy absorption characteristics remain near the vehicle body limit load and do not exceed this limit. Furthermore, since it has a lattice-like structure, the walls of the lattice-like structure gradually collapse from above, and the absorption characteristics become flat near the vehicle body limit load.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The energy absorber for a vehicle bumper according to the present invention will be described below with reference to the embodiments shown in the accompanying drawings.

FIG. 1 shows the state in which the energy absorber for a vehicle bumper according to the present invention is installed in a vehicle. In the figure, 1 is the energy absorber according to the present invention, 2 is a reinforcement, 3 is a skin member, and 4 is an energy absorber according to the present invention. is the vehicle body, and 5 is the side member. The energy absorber is fixed to a reinforcement 2, and this reinforcement 2 is fixed to a side member 5 or the like of the vehicle body 4 by a predetermined means. Further, the skin member 3 covers the energy absorber 1, the reinforcement 2, etc. to form an external appearance. The energy absorber 1 is made of resin (EVA, PE, PP,
TPE, etc.) and has a lattice-like structure. Further, the reinforcement 2 is made of glass fiber reinforced resin or aluminum alloy extrusion material. Note that l in the figure is the allowable deformation amount (rear side deformation amount) of the reinforcement 2.

FIG. 2 shows an embodiment of the energy absorber according to the invention. In this embodiment, the lattice surface of the energy absorber 1 on which the external force acts is 65 mm in the height direction of the outer wall (vehicle body direction).
%, and a cutout 6 of 30% in the width direction of the lattice surface (with the top and bottom being the width direction) is provided. This energy absorber 1 is deformed in the order shown in FIG. In this deformation, the energy absorption characteristics rise sharply at the beginning of the collision. Furthermore, since a part (upper part) of the energy absorber 1 with the resin lattice structure is cut out,
Deformation (rolling) of reinforcement 2 occurs,
Coupled with this, the bending moment is
It takes. This causes not only compression buckling but also bending deformation in the energy absorber 1. For this reason, the energy absorption characteristics remain near the vehicle body limit load and do not exceed this limit. Furthermore, since it has a lattice-like structure, the walls of the lattice-like structure gradually collapse from above, and the absorption characteristics become flat near the vehicle body limit load.

In the embodiment shown in FIG. 4, the lattice surface on which external force acts is oriented 65% in the height direction of the outer wall (vehicle body direction), and the width direction of the lattice surface (left and right being the width direction) is oriented toward the outside of the vehicle body. te30
% notch 6 is provided. In this example,
The energy absorbers are arranged symmetrically, and in combination with the deformation of the reinforcement 2, a bending moment is generated in the energy absorbers in the outward direction, causing bending deformation in the notch (FIG. 5). The energy absorption characteristics of the energy absorber in this case are as shown by the broken line in FIG.

In the embodiment shown in FIG. 4, if a V-shaped notch 7 of 1 to 90% is provided in the height direction indicated by the dotted line,
Flatness characteristics near the vehicle body limit load are further improved.

In the embodiment shown in FIG. 6, a lattice surface formed by providing the above-mentioned notches 6 is formed on the slope 8. As a result, there are multiple starting points where bending moments occur, and as shown by the solid line in FIG. 7, the flatness characteristics near the vehicle body limit load are further improved.

[0014] The cutout provided in the energy absorber is such that the lattice surface on which external force acts is 20 to 90% in the height direction of the outer wall.
, shall be provided by cutting out 10 to 50% in the width direction of the lattice surface. In the range below these, no effect will be seen. In addition, although it is more effective if the notch 6 is deeper in the height direction to some extent, if the notch is made 100% in the height direction, the pattern shown in Figures 12 and 13 will be obtained, ensuring the amount of energy absorption. Can not. Note that the portion where the notch is provided is not limited to the above embodiment, and depending on the design conditions, the notch may be provided from below the energy absorber or from the direction of the vehicle body. Furthermore, the energy absorbers 1 can be arranged as appropriate, such as 2, 4, or 6 energy absorbers on the left and right, and the effect is great when they are arranged in places where the reinforcement 2 is highly deformed.

[0015]

According to the present invention, since the energy absorption characteristics of the energy absorber are improved, it is possible to reduce the weight, size, and cost of the energy absorber. In addition, the performance of the reinforcement can be effectively used, and the miniaturization reduces restrictions on external design, which has great effects.

[Brief explanation of the drawing]

FIG. 1 is an exploded view illustrating a state in which an energy absorber for a vehicle bumper according to the present invention is attached to a vehicle body.

FIG. 2 is a perspective view of an embodiment of the energy absorber for a vehicle bumper according to the present invention.

FIG. 3 is a cross-sectional view illustrating the function of the energy absorber for a vehicle bumper according to the present invention.

FIG. 4 is a perspective view of another embodiment of the energy absorber for a vehicle bumper according to the present invention.

5 is a plan view illustrating the action of the energy absorber of the embodiment shown in FIG. 4; FIG.

FIG. 6 is a perspective view of still another embodiment of the energy absorber for a vehicle bumper according to the present invention.

FIG. 7 is a graph illustrating the energy absorption characteristics of the vehicle bumper according to the present invention.

FIG. 8 is an exploded view illustrating a state in which a conventional vehicle bumper energy absorber is attached to a vehicle body.

FIG. 9 is a graph illustrating the absorption characteristics of the energy absorber of a conventional vehicle bumper.

FIG. 10 is a graph illustrating the reinforcement absorption characteristics of a conventional vehicle bumper.

FIG. 11 is a cross-sectional view illustrating the function of a conventional energy absorber of a vehicle bumper.

FIG. 12 is a graph illustrating the absorption characteristics of the energy absorber of a conventional vehicle bumper.

FIG. 13 is a graph illustrating the reinforcement absorption characteristics of a conventional vehicle bumper.

[Explanation of symbols]

1 Energy absorber 2　Reinforcement 3.Skin member 4 Vehicle body 6 Notch A, C Vehicle body limit load

Claims (3)

[Claims] Claim 1: An energy absorber having a resin lattice structure attached to a resin or metal reinforcement of a vehicle bumper, in which the lattice surface of the energy absorber to which external force acts is located in the height direction of the outer wall. An energy absorber for a vehicle bumper, characterized in that a notch is provided in the width direction of the lattice surface by 20 to 90% and 10 to 50% in the width direction. 2. The energy absorbing bumper for a vehicle according to claim 1, further comprising a notch-shaped cut of 1 to 90% in the height direction on the lattice surface of the energy absorber on which external force acts. body. 3. The energy absorber for a vehicle bumper according to claim 1, wherein the lattice surface formed by providing the notches is formed as a slope.