JPH05155251A - Door reinforcement and its manufacturing method - Google Patents

Abstract

(57) [Summary] (Correction) [Purpose] To provide a tubular reinforcing member provided with brackets at both ends installed inside a door to ensure the safety of passengers against side collision of a vehicle. [Structure] After splitting both ends of the steel pipe by a predetermined length,
The portion is compressed into a flat shape, the bracket 2 is inserted between the two flat plate-like bodies 4, and the plate-like body 4 and the bracket 2 are joined by spot welding 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reinforcing member installed inside a door for the purpose of protecting a occupant from a side collision of an automobile, and a manufacturing method thereof.

[Prior Art]

2. Description of the Related Art Conventionally, a reinforcing member has been installed inside a door for the purpose of protecting a occupant from a side collision of an automobile. As such a reinforcing member, as shown in FIG. 2, the horizontally elongated members 10 and 11 made of a steel plate are embossed by pressing so as to have peaks 10a and 11a and valleys 10b and 11b, and then two horizontally elongated members are formed. In order to secure the load bearing strength of the central portion which is important for impact resistance characteristics, the reinforcing plates 12 and 12 are spot-welded to the ridges 10a and 11a to have a closed cross-sectional shape (for example, JP-A-64- 1
116). Further, as shown in FIG. 3, a notch (19, 20) is provided at an end of the steel pipe 17, and the portion is expanded and crushed into a flat plate shape to fix the fixing flange (1
8) (Formula 62-78519)
There is. Still another example of the reinforcing material is a steel pipe 1 having a bracket 3 arc-welded 2 as shown in FIG.

[0003]

When a steel plate is used as a reinforcing material, the welding method for forming a closed cross section is spot welding, but impact load is concentrated on the spot welded portion when a side collision of an automobile occurs. Then, destruction of this part occurs rapidly. Therefore, there is a problem that the welded portion is broken before the reinforcing material sufficiently absorbs the collision energy, and the absorbed energy of the reinforcing material is relatively small.

Further, since the strength distribution of the door reinforcing member in the longitudinal direction decreases almost monotonously from the central portion to the end portion, the strength at the end portion is insufficient and the breakage occurs at this portion. As a result, there may be a problem that the desired performance cannot be exhibited. Furthermore, the manufacturing process is complicated and the number of steps is large, and there is a problem in terms of manufacturing cost.

On the other hand, when a steel pipe is used as a material, the impact load is substantially evenly distributed over one cross section, so that there is an advantage that rapid breakage hardly occurs and a large amount of energy is absorbed. However, as shown in FIG. 3, the one in which the end portion of the steel pipe is expanded and attached to the bracket has a problem that the strength at the end portion is insufficient as in the above case and the portion is broken.

FIG. 4 is intended to improve such a problem. In this method, since the steel pipe is arc-welded to the bracket, it is necessary to press-form the bracket along the outer diameter of the steel pipe. However, as is well known, press forming and arc welding have problems in mass productivity and economical efficiency.

[0007]

The present invention solves all the problems of the above-mentioned prior art. That is,
While maintaining the excellent strength characteristics of steel pipes, the mass productivity and economic efficiency of spot welding are adopted.

[0008]

According to the present invention, in consideration of the current manufacturing process, in order to manufacture a door reinforcing material which is more excellent in mass productivity and economical efficiency, "the two end portions of the steel pipe are divided into two by a predetermined length in the longitudinal direction, Is crushed into a flat plate shape, and a bracket is inserted between the flattened two overlapping plate-like bodies for welding and assembly. "
It is characterized by By flattening the ends and inserting the bracket between them, the three plates will overlap, and it is possible to assemble by any welding method. Further, when the end portion is flattened, it is possible to adjust the assembly position with the bracket as shown in FIGS. 5- (a) and 5- (b) by deploying vertically symmetrically or asymmetrically.

[0009]

EXAMPLE Next, a specific manufacturing process of the door reinforcing material of the present invention will be described with reference to FIG. After cutting a long steel pipe into a length determined by the size of the door, the heat treatment is applied with a predetermined heat treatment to give the necessary strength and toughness only to the central portion indicated by the hatching in the length direction. ..

As another method, the long tube is not cut, and heat treatment is regularly performed at a predetermined interval in a predetermined range, and then the long length after heat treatment is performed at the center of each portion not subjected to the heat treatment. The length of pipe is cut into a plurality of heat-treated steel pipes. In addition,
When the material of the raw pipe is high-strength steel having sufficient strength and toughness, heat treatment is not required, and the long length can be directly cut into a predetermined length and sent to the subsequent processing step.

The cut steel pipe thus obtained is then cut at a predetermined depth so as to divide the cross-section circle into two parts depending on the diameter from both end faces toward the center. Next, a compressive force is applied to the steel pipe at right angles to an imaginary plane where a cut is formed in the two split parts at both ends, and the steel pipe is flattened into a spatula shape.

Then, brackets of a predetermined shape are inserted into the cutouts at both ends of the steel pipe, sandwiched between the spatula-shaped portions, and the flat portions after the three layers of brackets are inserted are firmly fixed by spot welding. This bracket is fixed to the frame inside the door. As shown in FIG. 1, one end portion of the completed door reinforcing material of the present invention is composed of a steel pipe body 1, a bracket 2, a spot weld portion 3, and a steel pipe end flat portion 4. As described above, the door reinforcing material of the present invention has a significantly simplified manufacturing process as compared with the conventional manufacturing method, and is excellent in the function as a reinforcing material.

【The invention's effect】

In consideration of the present manufacturing process, the present invention makes it possible to supply a door reinforcing material which is excellent in mass productivity and economical efficiency without impairing strength characteristics.

[Brief description of drawings]

FIG. 1 is a view showing a door reinforcing material according to the present invention.

FIG. 2 is a view showing a conventional door reinforcing material.

FIG. 3 is a view showing a door reinforcing material according to another conventional example.

FIG. 4 is a view showing a door reinforcing material according to still another conventional example.

FIG. 5 is a view showing a procedure for assembling the steel pipe and the bracket of the door reinforcing material according to the present invention.

FIG. 6 is a diagram showing a procedure for manufacturing a door reinforcing material according to the present invention.

[Explanation of symbols]

 1 Steel pipe body 2 Bracket 3 Spot weld 4 Steel pipe end flat

Claims (2)

[Claims] 1. A steel pipe body characterized by welding and assembling two overlapping plate-like members, which are flattened by crushing both ends of the steel pipe divided into a predetermined length in the longitudinal direction, and a bracket inserted therebetween. And door reinforcements consisting of brackets at both ends. 2. A steel pipe is subjected to a hardening heat treatment except both ends, and both ends are divided into two in the longitudinal direction, and at the same time, flattened,
A method for manufacturing a door reinforcing material, characterized in that separately molded brackets are inserted into both ends of a flat steel pipe, and they are assembled and integrated by spot welding.