JPH09156367A - Door impact beam - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a door impact beam capable of improving bending strength and absorbing collision energy at a low cost while achieving a lightweight and compact structure. SOLUTION: In a door impact beam 1 which is installed inside a door of a vehicle so as to be oriented in the door width direction and fixed at both ends, a beam main body 2 which connects between attachment parts 5 at both ends.
Is composed of a cylindrical steel pipe 3 and a long steel plate 4 inserted into the cylindrical steel pipe 3. The steel plate 4 has both ends fixed to the mounting portions 5 and 5, and the center thereof is in the door outward direction. A door impact beam that bulges and curves to contact the inner surface of the cylindrical steel pipe 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a door impact beam which is mainly arranged inside a door of an automobile or the like and absorbs energy of impact from a side surface.

[0002]

2. Description of the Related Art A door impact beam provided inside a door of an automobile or the like generally has a structure in which a steel pipe is used for a beam body, and mounting portions at both ends are fixed to a door frame so that the beam body is installed. When an external force is applied to the central part of the beam body, the stress concentrates on the part that receives the force.

Therefore, there is an example in which a reinforcing member having a double structure in the central portion of the beam main body having a large bending moment is inserted or externally inserted to increase the wall thickness to increase the rigidity.
Various proposals have been made in Japanese Patent Publication No. 92719, Japanese Patent Laid-Open No. 4-95526, Japanese Utility Model Laid-Open No. 4-11115, and the like.

[0004]

In either case, the thickness of the central portion of the beam main body is increased to increase the rigidity and to avoid the concentration of stress to disperse and increase the bending strength. It is limited to the main body, and its bending strength is not improved and collision energy absorption is small, despite the increase in weight and size due to the increase in wall thickness and diameter.

[0005] The present invention has been made in view of such a point,
The purpose of this is to provide a door impact beam that can improve bending strength and absorption of collision energy at a low cost while achieving lightweight and compactness.

[0006]

In order to achieve the above object, the present invention relates to a door impact beam which is installed inside a door of a vehicle with its both ends fixed in the width direction of the door and fixed at both ends. The beam main body that connects the two is composed of a cylindrical steel pipe and a long steel plate that is inserted into the cylindrical steel pipe.The steel plate has both ends fixed to the mounting portion and the center bulges outward of the door. The door impact beam is curved so as to be in contact with the inner surface of the cylindrical steel pipe.

The external force applied to the central portion of the beam body, which has a large bending moment, is received not only by the cylindrical steel pipe but also by the curved portion of the steel plate inserted inside that is in contact with the inner surface of the steel pipe. Since it is dispersed up to the mounting part, the bending strength is greatly improved and collision energy is also absorbed. It has a simple structure in which a steel plate is inserted inside a steel pipe, and it is possible to reduce the weight and size and cost.

The door impact beam according to claim 1, wherein at least one long steel plate is attached to the inner surface of the curved steel plate so as to adjust the number of steel plates to be overlapped as necessary, and thus the bending strength. Can be easily adjusted.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment according to the present invention will be described with reference to FIGS. The door impact beam 1 according to the present embodiment is arranged in a door of an automobile, and the beam main body 2 is composed of one steel pipe 3 and one steel plate 4 inserted therein, Brackets 5 and 5 for attachment to a door frame are fixed to both ends of the main body 2.

In the door impact beam 1, the brackets 5 and 5 are fixed to the door frame in the front and rear of the door, and the beam main body 2 is installed between the brackets 5 and 5 in the front-rear direction.

The steel pipe 3 has a long cylindrical shape, and the steel plate 4 inserted therein has a long rectangular plate shape.
From one end to the other end, and is curved in an arched shape, and both ends project from the steel pipe 3 to some extent.

On the other hand, the bracket 5 is formed by pressing a rectangular steel plate, and the upper and lower sides 5a, 5a are slightly bent, a recess 6 is formed in the central portion, and ribs 5b, 5c are formed on the upper and lower sides thereof.

The recess 6 is provided on the front and rear brackets 5.
2 and 3 from the inner side 5d facing each other toward the other outer side 5e.
As shown in the drawing, near the inner side 5d of the recess 6, there is formed a semicircular arc portion 6a formed in a semicircular arc shape so that the end portion of the steel pipe 3 can be fitted therein, and at the inner side thereof, a rectangular concave portion 6b which is recessed in a substantially rectangular shape After being formed, the inclined portion 6d is formed to be tapered through the bent portion 6c and is continuous with the flat surface of the bracket 5.

In the assembling work of the door impact beam 1, first, the curved steel plate 4 is inserted into the steel pipe 3, the end of the steel pipe 3 is fitted into the semi-circular arc portion 6a of the recess 6 of the bracket 5, and at the same time, the steel pipe 3 is inserted. The end of the steel plate 4 protruding from the rectangular recess 6
b.

Then, the end portion of the steel pipe 3 is welded to and integrated with the semi-circular arc portion 6a of the recess 6 of the bracket 5. In this way, the manufacturing work is simple, and it is possible to process and manufacture with conventional equipment, and there is no need to change the manufacturing equipment.

When the brackets 5 and 5 are attached to both ends of the beam body 2 in the same posture as described above, the steel plate 4 in the steel pipe 3 has both ends 4b and 4b fitted into the rectangular recess 6b of the recess 6 of the bracket 5. And the curved portion 6c,
The central portion 4a contacts the inner peripheral surface of the steel pipe 3 (see FIG. 3).

The door impact beam 1 has the above-mentioned structure, and the curved central part 4 of the steel plate 4 is curved and swelled.
It is arranged inside the door so that a is directed to the outside of the door.

The change in the bending load F with respect to the stroke (displacement) S when an external force is applied to the central portion of the door impact beam 1, that is, the bending strength characteristic A is shown by the solid line in FIG. For comparison, a broken line shows a bending strength characteristic B of a conventional door impact beam in which only a steel pipe having no steel plate inside is used as a beam body.

In the case of the door impact beam 1, when the bending load F is applied to the center of the beam body 2, the load F is applied to the steel pipe 3.
The steel plate 4 that is in contact with the inner surface of the steel pipe 3 is also received by itself, and the curved steel plate 4 can disperse the stress of the load received at the central portion 4a to the end portions 4b and 4b. Therefore, the bending strength characteristic A In comparison with the conventional bending strength characteristic B, the elastic modulus dF / dS is about twice as high in the low stroke region and the absorbed energy ∫Fds is about 1.5 times larger.

As described above, the beam main body 2 is composed of the steel pipe 3 and the steel plate 4, so that the beam main body 2 can be made light and compact, and at the same time, the bending strength can be improved. Further, the material cost is reduced, the manufacturing work is easy, and the cost can be reduced.

Next, another embodiment will be described with reference to FIG. The door impact beam 11 is the same as the door impact beam 1 of the above embodiment except for the steel plate 14,
The same members shall use the same reference numerals.

The steel plate 14 is formed by welding a curved steel plate 15 having a slightly shortened size on the curved inner surface of the central part thereof and welding the steel plate 15 on the inner surface of the steel plate 15 having a further shortened size. It is attached.

Although the weight increases, the rigidity increases and the bending strength increases. In the above embodiment, the steel plate 14 has two steel plates 15, 16
However, the bending strength can be easily adjusted depending on the number of steel plates to be stacked.

Therefore, by stacking a minimum number of steel plates satisfying the required bending strength, the required bending strength can be ensured while reducing the weight. By preparing various thicknesses of the steel sheets to be stacked, the bending strength can be adjusted more finely.

[0025]

The present invention has a simple structure in which the beam main body is composed of a cylindrical steel pipe and a curved steel plate inserted therein, and it is possible to reduce the weight and size of the beam and the cost thereof, and to improve the bending strength. Also, the absorption of collision energy can be increased.

By providing a door impact beam in which at least one long steel plate is attached to the inner surface of a curved steel plate, the number of steel plates to be stacked can be adjusted as necessary to easily adjust the bending strength. It is possible to provide a door impact beam that is as light as possible with optimal bending strength.

[Brief description of the drawings]

FIG. 1 is a perspective view of a door impact beam according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a sectional view taken along the line III-III in FIG. 1;

FIG. 4 is a diagram showing bending strength characteristics of the door impact beam.

FIG. 5 is a cross-sectional view of a door impact beam according to another embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Door impact beam, 2 ... Beam main body, 3 ... Steel pipe, 4 ... Steel plate, 5 ... Bracket, 6 ... Recessed part, 11 ... Door impact beam, 14, 15, 16 ... Steel plate.

Claims (2)

[Claims] 1. In a door impact beam erected inside a door of a vehicle so as to be oriented in the door width direction and fixed at both ends, the beam main body connecting between the mounting portions at both ends has a cylindrical steel pipe and the same cylindrical shape. It is composed of a long steel plate inserted into a steel pipe, the steel plate is fixed at both ends to the mounting portion, the center bulges outward of the door and curves to contact the inner surface of the cylindrical steel pipe, Door impact beam to do. 2. The door impact beam according to claim 1, wherein at least one long steel plate is attached so as to overlap the inner surface of the curved steel plate.