JPH028849Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field The present invention is a bumper reinforcement made of a metal plate that is placed inside a bumper fascia made of an elastic material such as resin or rubber to reinforce the bumper fascia. Regarding.

BACKGROUND OF THE INVENTION In recent years, so-called soft bumpers with elasticity have been frequently used as bumpers for automobiles as a measure for pedestrian safety and as a measure to protect the appearance in the event of a minor collision. As shown in Figure 1, this soft bumper is made of appropriate resin,
Bumper fascia 1 made of elastic material such as rubber
and a bumper reinforcement 2 made of a metal plate and having a substantially U-shaped cross section and arranged inside the bumper fascia 1 to reinforce the bumper fascia 1. A required space plate 3 is set between the front wall 1a of the bumper fascia 1 and the front wall 2a of the bumper reinforcement 2, and the upper and lower walls 1b and 1c of the fascia are connected to the upper and lower walls 2b and 2c of the reinforcement. Each is fixed with bolts, nuts, etc. not shown. This bumper reinforcement 2 is generally press-molded into a U-shape using a foam-type press machine, but the bumper reinforcement 2 can be formed into an arbitrary shape according to the longitudinal curvature of the main part of the bumper fascia 1. Due to the fact that they are formed with curvature, there is a difference in the radius of curvature between the front and rear edges of the upper and lower walls 2b and 2c of the bumper reinforcement 2.
Wrinkles occur on the lower walls 2b and 2c due to the excess thickness of the plate materials. Therefore, in order to prevent the occurrence of wrinkles during press forming, as shown in FIG. A plurality of bead portions 4 are formed to allow excess thickness of the plate material to escape, thereby avoiding wrinkles.

However, in such a conventional structure, the wrinkle removing bead portion 4 is formed on the reinforcement from the front edge ridgeline to the rear edge of the lower walls 2b, 2c.
When an external force is applied to the bumper reinforcement 2 during a minor vehicle collision, stress concentrates on the bead portion 4 and the bumper reinforcement 2 tends to bend particularly in the front and rear directions, which poses a problem in terms of strength. It was hot. Considering this with reference to FIGS. 4 and 5, if there is no wrinkle-removing bead 4 on the upper and lower walls 2b and 2c of the bumper reinforcement 2, wrinkle removal beads 4 will appear on the front wall 2a due to a minor vehicle collision. When a depression A occurs as shown in Figure 4, the front wall 2a and the upper and lower walls 2
The ridgeline portion at the border between b and 2c is drawn into the recess A side and disappears, and both sides of this ridgeline disappearing portion tend to bulge, causing a change in the wave shape as shown by the chain line in the same figure. be. On the other hand, in the case where the wrinkle-removing bead portions 4 are recessed in the upper and lower walls 2b and 2c from the ridgeline to the rear edge as shown in FIG. A
When this occurs, the ridgeline at the front edge of the bottom of the wrinkle-removal bead portion 4 disappears due to the above-mentioned reason, and both sides of this ridgeline disappearing portion bulge, but since the ridgeline curves upward in this portion, The upheaval phenomenon is likely to be promoted, and as shown by the chain line in the same figure, the change in the wave shape becomes large, and stress is concentrated in this area. In addition to this phenomenon, when a collision load is applied to the front wall 2a of the bumper reinforcement 2, this external force acts in a direction that expands the U-shaped cross section, so as mentioned above, the collision load acts from the ridgeline to the rear edge. When the wrinkle removing bead 4 is recessed, the upper and lower walls 2b, 2c
Stress in the expanding direction is concentrated on the bead concave portion, and bending starting from the wrinkle removing bead portion 4 is likely to occur. This lack of strength can be compensated for by increasing the thickness of the bumper reinforcement 2, but this would increase the weight and go against the need to reduce the weight of the vehicle body, which is desired to improve fuel efficiency and output. Become.

Purpose of the invention In view of the conventional situation, it is an object of the present invention to provide a bumper reinforcement that can prevent the occurrence of wrinkles on the upper and lower walls during press molding without impairing the strength of the bumper reinforcement. The purpose is to

Structure of the invention In order to achieve the above-mentioned purpose, the invention has the following features:
A bumper reinforcement having a substantially U-shaped cross section and having a curvature in the front-rear direction to be disposed inside a bumper fascia and reinforcing the bumper fascia, the bumper reinforcement comprising: Made of steel plate material that has been cut in advance so that the rear edges of the upper and lower walls of the bumper reinforcement are shorter than the ridgeline between the upper and lower walls and the front wall. The blank is press-formed into a substantially U-shaped cross section, and wrinkle-removing bead portions are recessed in the upper and lower walls by a cam member incorporated into the press die at the same time as the press-forming. , wrinkle-removal bead portions are formed on the upper and lower walls of the bumper reinforcement at the same time as the press molding and are formed into a substantially U-shaped cross section, along the ridge line between the front wall and the lower wall of the bumper reinforcement. , in the plane between the rear edges of these upper and lower walls,
The cross section is wedge-shaped, with the depth gradually increasing toward each trailing edge.

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings, with the same reference numerals assigned to the same parts as in the conventional structure.

That is, in the case of the present invention, as shown in Fig. 3,
By molding the bumper reinforcement 2, which has a substantially U-shaped cross section, with an arbitrary curvature in the front-rear direction, the upper and lower walls 2b and 2, which have the highest tendency to wrinkle, are formed.
c, a bead for removing wrinkles during press molding, which is formed simultaneously with the press molding of the U-shaped cross section, within the plane thereof, that is, within the wall surface between the ridgeline of the boundary with the front wall 2a and the rear edge. The portions 4A are recessed at a plurality of locations. Specifically, the wrinkle removing bead portion 4A is formed by cam members such as a slide cam and a drive cam that are incorporated into the press mold at the same time as the bumper reinforcement 2 is press-formed into a substantially U-shaped cross section. It is recessed in the walls 2b and 2c. In addition, when blanking the bumper reinforcement blank, the length of the portion that will become the trailing edge is formed shorter than the portion that will become the ridgeline in advance, so that the bumper reinforcement 2 has a planar arc shape with curvature in the front and rear direction. Spring back is prevented as much as possible when press molding is carried out. In this way, even if the wrinkle-removing bead portion 4A is located within the wall surface that does not touch the front edge ridgeline and rear edge of the upper and lower walls 2b and 2c, the wrinkle-removing bead portion 4A is located on the upper and lower walls 2b and 2c. Since the trailing edge side is formed deeply, if excess thickness of the plate material is generated at the rear edges of the upper and lower walls 2b and 2c during press forming, this excess thickness will be removed when forming the wrinkle removal bead portion 4A. The excess material can be drawn into the wrinkle-removal bead portions 4A, and the excess meat can be sufficiently released by these wrinkle-removal bead portions 4A. Therefore, it is possible to prevent the occurrence of wrinkles, which is almost comparable to conventional methods.
In this way, the wrinkle-removing bead portions 4A are located within the planes of the upper and lower walls 2b and 2c, respectively, and since the wrinkle-removing bead portions 4A are not present on the leading edge ridgeline and the rear edge, collisions, etc. When an external force is applied to the surface of the front wall 2a, the bumper reinforcement 2 retains its substantially U-shaped cross-sectional shape effect, which forms the ridge line, and prevents stress from being concentrated in a specific part. The bending strength of the reinforcement 2 can be further improved.

In addition, depending on the case, the wrinkle-removing bead portion 4A may also be set within the front wall 2a of the bumper reinforcement 2 so as not to overlap the ridgeline.

Effects of the invention As described above, according to the invention, wrinkles on the upper and lower walls during press molding of a bumper reinforcement can be reduced by using the wrinkle removing bead formed at the same time as the press molding. Not only can it be effectively prevented, but also
The wrinkle removing bead portion meets the ridgeline of the boundary with the front wall,
The effect of the generally U-shaped cross section of the bumper reinforcement having a ridgeline in the plane between the rear edges of the upper and lower walls is not impaired. As a result, even if an external force is applied to the front wall during a frontal collision, stress will not be concentrated on the molded part of the wrinkle removal bead.
Therefore, it is possible to improve the bending strength of the bumper reinforcement without increasing the thickness of the bumper reinforcement, and it has a great practical effect of improving both quality and reliability.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a soft bumper equipped with a bumper reinforcement, Fig. 2 is a perspective view showing an example of a conventional bumper reinforcement, and Fig. 3 is a perspective view showing an embodiment of the present invention. 4 and 5 are schematic perspective views showing the process of bending and deforming a conventional bumper reinforcement, respectively. 1...Bumper fascia, 2...Bumper reinforcement, 2a...Front wall, 2b...Top wall, 2
c...Bottom wall, 4A...Wrinkle removal bead part.

Claims (1)

[Scope of utility model registration request] A bumper reinforcement having a substantially U-shaped cross section and having a curvature in the front-rear direction to be disposed inside a bumper fascia and reinforcing the bumper fascia, the bumper reinforcement comprising: When cutting the blank in advance, determine the length of the part that will become the rear edge of the upper and lower wall of the bumper reinforcement.
Blanks made of steel plates are formed shorter than the ridge line between the upper and lower walls and the front wall, and are press-formed into a U-shaped cross section, and simultaneously assembled into a press mold. In the structure in which wrinkle-removing bead portions are recessed in the upper and lower walls by a cam member, the wrinkles are recessed in the upper and lower walls of the bumper reinforcement at the same time as press molding having a substantially U-shaped cross section. Place the removal bead in the plane between the ridge line between the front wall of the bumper reinforcement and the upper and lower walls, and the rear edges of these upper and lower walls, as it reaches each rear edge side. A bumper reinforcement characterized by a wedge-shaped cross section that gradually increases in depth.