JPH08276804A - Collision energy absorbing member for automobile - Google Patents

Abstract

PURPOSE: To provide a collision energy absorbing member for an automobile in which a pressure receiving area can be enlarged in spite of a limited end face area of a structural member. CONSTITUTION: A collision energy absorbing member 10 is attached to a structural member 12 such as a front side member of an automobile. The collision energy absorbing member comprizes a cylindrical side wall 12, an attaching surface 16 provided on one end of the side wall 14 and attached to the structural member 12, a hitting contact surface 18 provided on the other end of the side wall 14 so as to cap the side wall 14, and a plurality of slits 20 provided on the side wall 14 and extending in the axial direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a collision energy absorbing member for an automobile, and more particularly to a collision energy absorbing member suitable for mounting on a structural member such as a front side member or a rear side member of an automobile.

[0002]

2. Description of the Related Art When a synthetic resin bumper cover is directly attached to a structural member such as a front side member or a rear side member of an automobile body, a collision called a crash box between the bumper cover and the end surface of the structural member. An energy absorbing member may be arranged (Japanese Patent Application Laid-Open No. HEI 06-242242).
6-171443).

[0003]

Since the area of the end surface of the structural member is limited, the size of the collision energy absorbing member is limited, and the pressure receiving area of the collision energy absorbing member is small. Therefore, when a load is applied from the bumper cover, the stress generated in the bumper cover becomes large, and the bumper cover is greatly damaged.

An object of the present invention is to provide a collision energy absorbing member for an automobile which can increase the pressure receiving area despite the limited area of the end face of the structural member.

[0005]

DISCLOSURE OF THE INVENTION The present invention is a collision energy absorbing member to be attached to a structural member of an automobile, which has a cylindrical side wall and a mounting surface provided at one end of the side wall and attached to the structural member. A contact surface provided on the other end of the side wall so as to close the side wall, and provided on the side wall,
And a plurality of slits extending in the axial direction.

The present invention also relates to an automobile in which a plurality of cylindrical energy absorbers having different diameters having mutually adjacent diameters are connected through an annular step portion to form a stepped shape tapering in the axial direction. The collision energy absorbing member to be attached to the structural member, the energy absorbing member having the smallest diameter is provided so as to close the energy absorbing member, and has a mounting surface to be attached to an end face in the axial direction of the structural member.

[0007]

According to the invention described in claim 1, when the mounting surface is mounted on the structural member and used, when a collision load of a predetermined value or more is applied from the contact surface, the plurality of slits are widened and the side wall has a cross section. It is transformed so that the area of
Absorbs collision energy.

Since the contact surface provided on the side wall of the collision energy absorbing member and the surface generated by the deformation of the side wall are the pressure receiving area, the pressure receiving area is increased by the amount of the deformation of the side wall, and a large collision load is received. Can be received in the area.

According to the second aspect of the invention, when the mounting surface provided on the energy absorber having the smallest diameter is mounted on the end surface of the structural member for use, the energy absorber having the largest diameter is moved forward or rearward of the automobile. Project toward the structural member. When a collision load of a predetermined value or more is applied to the energy absorber having the largest diameter, the reaction force causes the plurality of energy absorbers to buckle in order from the smaller diameter to absorb the collision energy. And when all the energy absorbers buckle, the collision energy absorbing member becomes a flat rigid body,
Substantially the entire pressure receiving area.

The collision load can be received with a large pressure receiving area. Particularly, since the mounting surface of the energy absorbing body having the smallest diameter of the collision energy absorbing member is mounted on the axial end surface of the structural member, the area of the mounting surface is the same as the end surface of the structural member having a limited area. However, the pressure receiving area is larger than that of the mounting surface. As a result, the stress generated in another member such as a bumper cover attached to the collision energy absorbing member is reduced, so that the collision energy absorbing member is deformed before the other member is damaged, and the collision energy can be sufficiently absorbed. Become.

Since the energy absorbing member is composed of a plurality of energy absorbing bodies and has a stepped shape tapering in the axial direction, the energy absorbing efficiency is high.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A collision energy absorbing member 10 is attached to a structural member 12 of an automobile with reference to FIG. 1 showing a first embodiment, and is provided on a cylindrical side wall 14 and one end of the side wall 14. An attachment surface 16 attached to the structural member 12, an abutment surface 18 provided on the other end of the side wall 14 so as to close the side wall 14, and a plurality of slits 20 provided on the side wall 14 and extending in the axial direction. Have.

The structural member 12 of the automobile is a front side member or a rear side member of the body, and the collision energy absorbing member 10 has the structural member 12 on the front end surface thereof when the structural member 12 is a front side member. , Then attached to the end face.

The side wall 14 of the collision energy absorbing member 10 is
In the illustrated embodiment, a substantially truncated pyramid-shaped tube,
Each of the two surfaces has a bead 22 extending in the axial direction and a bead 24 orthogonal to the bead 22 and smaller than the bead 22. Each bead is formed in a convex shape toward the outside. The bead 22 mainly serves to increase the rigidity of the side wall 14 in the axial direction. In contrast, bead 24
Mainly serves to allow the deformation of the side wall 14 to occur at the site of the bead 24 when a collision load larger than a predetermined value is applied.

Mounting surface 16 of collision energy absorbing member 10
Is a flange protruding from one end of the side wall 14 toward the outside in the radial direction, while the contact surface 18 is provided so as to close the other end of the side wall 14. The mounting surface 16 is the contact surface 1
As in the case of 8, the one end of the side wall 14 can be closed, but the structure shown in the drawing is preferable because the pressure receiving area of the collision energy absorbing member 10 can be maximized. The mounting surface 16 has a plurality of, for example, four bolt holes 26, and is attached to the structural member 12 by bolts (not shown) passing through the bolt holes 26. The contact surface 18 contacts a member (not shown) such as a bumper cover to which a collision load is applied.

In the illustrated embodiment, the plurality of slits 20 of the collision energy absorbing member 10 extend in the axial direction of the side wall 14 at the corners of the truncated pyramid and are circular at the portion corresponding to the bead 24. Is wider than other parts. The slit 20 facilitates the deformation of the side wall 14.

The collision energy absorbing member 10 has, for example, 1.
It can be obtained by deep drawing a thin iron plate of 0 to 2.0 mm. Collision energy absorbing member 10 thus obtained
Is attached to the structural member 12 by its mounting surface 16 and the contact surface 18 is abutted against a member such as a bumper cover for use.

When a load F of a predetermined amount or more is applied from a member such as a bumper cover, the collision energy absorbing member 10 has side walls 14 so that the slit 20 spreads as shown in FIG.
Deforms toward the outer side A in the radial direction. As a result, the pressure receiving area is the area of the contact surface 18, the area of the side wall 14 protruding outward from the contact surface 18, and the mounting surface 16 protruding from the slit 20 depending on the size of the mounting surface 16. The total area is the area of the part. Therefore, the collision energy absorbing member 10 receives the collision load in the increased pressure receiving area after being deformed as shown in FIG.

3 and 4 showing the second embodiment, the collision energy absorbing member 30 is composed of a plurality of cylindrical energy absorbers having different diameters, in the illustrated embodiment, three energy absorbers. 32, 34 and 36 having mutually adjacent diameters 32 and 34 are coupled to each other via an annular step portion 33, and mutually adjacent diameters 34 and 36 are coupled to each other through an annular step portion 35, and are connected in the axial direction. It is formed in a tapered stepped shape. In the illustrated embodiment, each energy absorber has a truncated pyramid shape having a lateral dimension larger than a vertical dimension. This is because a member such as a bumper cover to which a collision load to be absorbed by the collision energy absorbing member 30 is applied is long in the lateral direction of the body. Each of the energy absorbers has, in addition to the above-described shape, a truncated pyramid shape having substantially the same vertical and horizontal dimensions,
It can be shaped like a truncated cone.

The collision energy absorbing member 30 is attached to the structural member 12 of an automobile, and has an energy absorbing body 32 having the smallest diameter and a mounting surface 38 provided so as to close the energy absorbing body 32. Collision energy absorbing member 3
0 can be formed by deep drawing a thin iron plate of 1.0 to 2.0 mm, for example. The mounting surface 38 is formed by, for example, two bolts 40 and nuts 42, and the structural member 1
2 is attached to the end face 13 in the axial direction. as a result,
The energy absorber 36 having the largest diameter projects forward or backward from the structural member 12 and comes into contact with a member such as a bumper cover. In the illustrated embodiment, a flange 37 extending outward in the radial direction is attached to the energy absorber 36 having the largest diameter to form a contact surface.

When a collision load of a predetermined amount or more is applied from a member such as a bumper cover, first, the collision energy absorbing member 3
The energy absorber 32 having the smallest diameter of 0 is the structural member 1
The reaction force from 2 causes the step portion 33 to bend and deform, and the energy absorber 32 as a whole buckles and deforms. When the energy absorber 32 is sufficiently deformed, the energy absorber 34 having the next smallest diameter is bent and deformed at the step portion 35, and the whole thereof is buckled and deformed. In this way, the collision energy absorbing member 30 is gradually deformed and finally becomes a rigid body having a flat shape as a whole, as shown in FIG.

As shown in FIG. 5, before the collision energy absorbing member 30 is deformed, the collision energy absorbing member 30 and the structural member 12 are in contact with each other at a width B, and have a pressure receiving area proportional to the width B. It was On the other hand, after the collision energy 30 is deformed, the collision energy absorbing member 30 and the structural member 12 are
With the width B, the collision energy absorbing member 30 is a flat rigid body and has an effective width C (C> B), so that it has a large pressure receiving area proportional to the width C.

A collision energy absorbing member 50 in which a plurality of cylindrical energy absorbers having different diameters and having mutually adjacent diameters are coupled via an annular step portion to form a stepped shape tapering in the axial direction. However, for example, as shown in FIG. 7A, when the four energy absorbers 52, 54, 56, 58 have a so-called four-stage configuration, and the height of each energy absorber is L, the collision energy is The entire height of the absorbing member 50 is 4L. It has been experimentally confirmed that, when the collision energy absorbing member 50 is sufficiently deformed, its contact surface is located at a distance L / 2 from the surface of the object 60. Therefore, it can be said that the interval L / 2 does not function to absorb energy. In other words, (3
Only L + L / 2) is needed for energy absorption.
Therefore, as shown in FIG. 7B, if the collision energy absorbing member 70 in which L / 2 is distributed to the energy absorbing bodies of each stage is made, the collision energy absorbing member is not wasted and the energy is effectively absorbed. it can. Now, if the height of each energy absorber after sorting the L / 2 and L _0, the relationship between the _{3L 0 + L 0/2 =} 4L, the L ₀ = 8L / 7. Therefore, when the collision energy absorbing member 70 has four stages, it is preferable to set the height of each energy absorber to L ₀ . Generally, in an n-stage collision energy absorbing member, L ₀ = 2nL /
By setting (2n-1), it is possible to eliminate a wasteful interval L / 2 that does not function for energy absorption when the height of each energy absorber is L.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of a vehicle collision energy absorbing member according to the present invention.

FIG. 2 is a perspective view showing a state after the collision energy absorbing member shown in FIG. 1 is deformed.

FIG. 3 is a perspective view of another embodiment of the vehicle collision energy absorbing member according to the present invention.

FIG. 4 is a perspective view of the collision energy absorbing member substantially the same as the collision energy absorbing member shown in FIG. 3, viewed from another direction.

5 is a schematic diagram showing an effect of the collision energy absorbing member shown in FIG.

6 is a perspective view showing a state where the collision energy absorbing member shown in FIG. 3 is deformed, and a broken line shows an uneven shape.

FIG. 7 is a schematic view of the collision energy absorbing member shown in FIG. 3, in which FIG.
(B) shows an ideal mode in which the waste intervals generated in (a) are distributed.

[Explanation of symbols]

10, 30, 50, 70 Collision energy absorbing member 12 Structural member 14 Side wall 16, 38 Mounting surface 18, 37 Abutting surface 20 Slit 32, 34, 36, 52, 54, 56, 58 Energy absorber 33, 35 Step portion

Claims (2)

[Claims] 1. A collision energy absorbing member to be attached to a structural member of an automobile, which has a cylindrical side wall, and an attachment surface provided at one end of the side wall and attached to the structural member.
A collision energy absorbing member for an automobile, which has an abutting surface provided on the other end of the side wall so as to close the side wall, and a plurality of slits provided on the side wall and extending in the axial direction. 2. A structural member for an automobile, wherein a plurality of tubular energy absorbers having different diameters, which have mutually adjacent diameters, are connected through an annular step portion to form a stepped shape tapering in the axial direction. A collision energy absorbing member to be attached to,
A collision energy absorbing member for an automobile, which has a mounting surface which is provided on the energy absorbing body having the smallest diameter so as to close the energy absorbing body and which is attached to an end face in the axial direction of the structural member.