JPH11170934A - Bumper stiffener and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure sufficient structural strength by bending one side edge of an original plate in the order of a valley turned-up edge and a crest tucked-in edge, adhering a plane part from a side edge to the turned-up edge to the front surface of a bumper in the contact surface condition, and connecting the other side edge of the original plate with neighborhood of the tucked-in edge. SOLUTION: This stiffener has a cross sectional structure where a part from a turned-up edge 6 to a tucked-in edge 2 is linked as a so called reinforcing rib 8 between the front surface 4 of a bumper and the back surface 9 of the bumper. One of side edges constituting this reinforcing rib 8 is sandwiched between the turned-up edge (valley) 6 and the tucked-in edge (crest) 2 which have different bending directions, and can easily be formed by rolling molding of continuous processes. Because a plane part 7 connected with the reinforcing rib 8 is adhered to the front surface 4 of the bumper in the contact surface condition, integrality between the reinforcing rib 8 and the front surface 4 of the bumper is improved and buckling as the stiffener 1 is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bumper reinforcing member which is a strength member constituting a bumper of an automobile and a method of manufacturing the same.

[0002]

2. Description of the Related Art A bumper of an automobile is mounted on the automobile so that only a metal strength member can be seen from the outside. In recent years, a form in which a bumper reinforcing material as a strength member is covered with a plastic cover as a makeup member has been used. Many. The bumper in this form has the advantage that the design of the car is enhanced by making the plastic cover the same color as the car body color, and the reinforcement itself can pursue the performance as a strength member without worrying about the appearance. . At present, such a double-structured bumper is mainly used.

[0003] The reinforcing material is basically a tubular structure, and is a box-shaped cross-sectional type (actually 3-56129) in which two separately formed plate members are joined.
No., JP-A-7-256551, etc.) and a closed cross-section type formed by rolling one sheet material (JP-A-7-246894, JP-A-8-34302, etc.)
Can be roughly divided into Both stiffeners connect the front of the bumper to the plastic cover and connect the back of the bumper to the base of the vehicle. With the tubular structure, the space formed therein absorbs and disperses the force at the time of collision, and achieves the main purpose of protecting the vehicle body as a bumper.

In order to further improve the structural strength,
There is also an example in which another member such as a beam reinforcing plate or a bulkhead is attached to a reinforcing material (Japanese Patent Application Laid-Open No. Hei 6-171441, Japanese Patent Publication No. 63-1217).
No. 6-46765). Such addition of a separate member is often seen in box-shaped section reinforcements. In addition, from the viewpoint of improving the structural strength, there is also a method in which a material obtained by joining a plurality of plate materials having different materials or thicknesses is used as an original sheet, and a reinforcing material is manufactured by roll forming from this original sheet (Japanese Patent Laid-Open No. 6-227331) ).

[0005]

The requirements imposed on the reinforcement are (1) sufficient structural strength as a strength member of the bumper.
(Impact resistance), (2) weight reduction required to improve fuel efficiency of automobiles, and (3) low production cost. Of the above requirements, (1), (2), and (3) are contradictory. If the structural strength is increased, it is difficult to reduce the weight and reduce the manufacturing cost. Therefore, as a bumper, it is an important viewpoint how much (2) and (3) can be achieved while satisfying (1).

In view of the above, the reinforcing member must not have such a structural strength that buckling occurs at the time of collision and the protection of the automobile body cannot be achieved. For this reason, it is necessary to add a separate member for many reinforcing materials, and it has been inevitable that the number of parts as reinforcing materials increases and that an assembling step is added. In particular, if an assembling step is separately required, the advantage of roll forming, in which a reinforcing material can be manufactured continuously, is hindered, resulting in an increase in cost. Instead of adding a separate member, it is also conceivable to increase the thickness of the plate material to be used, but since this directly leads to an increase in the weight of the reinforcing material,
It is not a very good solution.

In view of this, while using another member for the purpose of reducing the manufacturing cost, a necessary and sufficient structural strength is secured without changing the plate thickness accompanying an increase in weight, and a continuous structure using roll forming is used. A bumper reinforcing material having a cross-sectional structure that can be manufactured was considered.

[0008]

As a result of the study, what has been developed is a bumper reinforcing material formed by rolling an original sheet into a tube, and one side edge of the original sheet is a folded edge of a valley.
Bumper reinforcing material which is bent in the order of the folded edge of the mountain, and a flat portion from the side edge to the folded edge is joined to the front surface of the bumper in a contact state, and the other side edge of the original plate is joined near the folded edge. It is. In this reinforcing material, the folded edge portion serves as a reinforcing rib connecting the front surface of the bumper and the rear surface of the bumper, and enhances the structural strength of the closed-section reinforcing material formed by roll forming which is usually hollow. Since the reinforcing rib joins the flat portion from the side edge to the folded edge to the front surface of the bumper in a state of contact, the integration with the front surface of the bumper is high. Folded edge,
Although the bending angle at the folding edge is free, it is preferable to make the reinforcing ribs perpendicular to the front and back surfaces of the bumper from the viewpoint of increasing the structural strength of the bumper.

The above-mentioned bumper reinforcing material is formed by successively performing roll forming on both side edges. (1) One side edge portion is formed on a continuously fed original plate in the order of a folded edge portion of a valley and a folded edge portion of a mountain. An inner roll forming step of bending and bringing a flat portion from a side edge to a folded edge portion into contact with the front surface of the bumper, an inner welding process of joining the flat portion and the front surface of the bumper continuously or intermittently, and the other side edge portion. An outer roll forming step of forming a closed cross section addressed to the vicinity of the folding edge, and an outer welding step of continuously joining the other side edge and the vicinity of the folding edge are manufactured using a manufacturing method of sequentially performing. .

[0010] Further, assuming that the roll forming of both side edges is performed as simultaneously as possible, (2) a method of manufacturing a tubular bumper reinforcing material is used. A front roll forming step in which the flat portion from the side edge to the folded edge portion is brought into contact with the front surface of the bumper by bending in the order of the folded edge portion of the mountain and simultaneously bending the other side edge portion to approach the folded edge portion, An inner welding process for continuously or intermittently joining the flat portion and the front surface of the bumper, a roll forming process for forming a closed cross-section by addressing the other side edge near the folding edge, and the other side edge It is good also as a manufacturing method which performs the outer welding process which joins continuously with the vicinity of a folding edge part in order. In this case, the bending of the other side edge in the pre-roll forming step is performed so as not to hinder the inner welding step. Since the roll forming of both side edges can proceed simultaneously, there is an advantage that the total length of the production line can be shortened as compared with the above production method.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a bumper reinforcing material and a manufacturing method according to the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing a basic appearance of a reinforcing member 1 to which the present invention is applied, FIG. 2 is a left side view of the reinforcing member 1, and FIG. 3 is a left side when the reinforcing member 1 is used upside down. FIG. 4 is a left side view corresponding to FIG. 2 of the reinforcing member 1 in which the other side edge portion 3 is joined to the folding edge portion 2 while being overlapped. Each of the reinforcing members 1 in the illustrated example has a substantially square pipe shape with rounded corners for convenience of description, and holes and the like for attachment to an automobile body and for covering a plastic cover are omitted.

As shown in FIGS. 1 and 2, the reinforcing member 1 of the present invention has one side edge 5 bent toward the front surface 4 of the bumper via the folding edge 2 and further folded at the folding edge 6. The flat part 7 from the side edge of the side edge part 5 to the folded edge part 6 is brought into contact with the bumper front face 4 and joined. For this joining, TIG welding, plasma welding, laser welding, or the like can be used in addition to spot welding described below. The other side edge 3 is abutted against the folding edge 2 and is continuously welded. TIG welding, plasma welding, laser welding, or the like can be used to join the other side edge 3 and the folded edge 2. In this manner, the tubular reinforcing member 1 having a closed cross section is formed from one original plate.

As shown in FIG. 2, the reinforcing member 1 of the present embodiment has a cross section in which a portion from the folded edge portion 6 to the folded edge portion 2 is a so-called reinforcing rib 8, which is provided between the front surface 4 of the bumper and the rear surface 9 of the bumper. It has a structure. One side edge 5 constituting the reinforcing rib 8 has a folded edge (valley) having a different bending direction.
6. It is sandwiched between the folded edges (mountains) 2 and can be easily formed by roll forming as a continuous process. Further, the flat portion 7 continuous with the reinforcing rib 8 is formed on the front surface 4 of the bumper.
By joining in a state in which the reinforcing ribs 8 and the bumper front surface 4 are joined, the buckling as the reinforcing member 1 is prevented.

The reinforcing member 1 of the present invention is used in the orientation shown in FIG. 3 in addition to the orientation shown in FIG. Further, in the reinforcing member 1 of the present embodiment, as shown in FIG. 2, the side edge of the other side edge portion 3 is joined to the folding edge portion 2 by line contact, but the tubular reinforcing member has a closed cross section. So long as it can be configured,
If the joining strength is taken into consideration, as shown in FIG. 4, the other side edge 3 may be brought into surface contact with the folded edge 2 so as to be superimposed thereon, and may be joined integrally.

FIG. 5 is a structural view showing a production line of the reinforcing member of FIG. 1, and FIGS. 6 to 10 are perspective views showing an original plate 10 and a tubular intermediate product 11 in each step of the production line. 7 is an original sheet 10 unwound from the uncoiler 12, FIG. 7 is a tubular intermediate product 11 after the inner roll forming process, FIG. 8 is a tubular intermediate product 11 in the middle of spot welding the flat portion 7 in the inner welding process, and FIG. FIG. 10 shows the tubular intermediate product 11 after the inner roll forming step, and FIG. 10 shows the tubular intermediate product 11 during laser welding of the other side edge 3 in the outer welding step. In the case of a reinforcing material having a gradually changing cross-sectional structure, a cutting step is added before or after each roll forming step.

An original plate (for example, a high-tensile steel plate) 10 is an uncoiler.
Repeat from 12 consecutively. The original plate 10 in this state is a long sheet material, and as shown in FIG. 6, has a form in which plate materials of a product length are connected. In FIG. 6, hatched portions represent portions corresponding to the bumper front surface 4, and lattice hatched portions represent portions corresponding to the reinforcing ribs 8. As shown in FIG. 7, the original plate 10 firstly bends one side edge 5 at the folded edge portion 6 and the folded edge portion 2 by forming a reinforcing rib 8 by passing through a front roll forming step. 7 is brought into contact with the front surface 4 of the bumper. In a reinforcing material having a gradually changing cross section, a linear flat portion having a constant width is brought into contact with the front surface of the bumper so that the contact surface relationship with the front surface of the bumper becomes uniform.

As shown in FIG. 8, the flat portion 7 is intermittently roll-spot-welded while being addressed to the roll spot welder 13 from above and below, and joined to the front surface 4 of the bumper. At the stage of the inner welding step, the other side edge 3 remains open, so that the roll spot welding machine 13 as shown in FIG. 8 can be used for joining the flat portion 7 to the bumper front surface 4.

As shown in FIG. 9, the tubular intermediate product 11 sent to the subsequent outer roll forming step bends the other side edge portion 3 so that the side edge abuts on the folding edge portion 2. Then, in the outer welding step, as shown in FIG. 10, for example, the side edge of the other side edge 3 and the folding edge 2 are continuously joined by using a laser welding machine 14, and a book having a closed cross section is obtained. Example reinforcing material 1 (see Fig. 1)
Constitute a tubular intermediate product 11 having an external appearance. In the production line, the tubular intermediate product 11 is finally cut and separated for each product length in a cutting and separating step (right end in FIG. 5), and the reinforcing material 1 as a product is cut.
(See FIG. 1).

FIG. 11 is a block diagram showing another example of the production line of the reinforcing member 1 shown in FIG. 1, and FIG. 12 is a perspective view showing the tubular intermediate product 11 in the pre-roll forming step of the production line. FIG. 3 is a perspective view showing a tubular intermediate product 11 in the middle of spot welding a flat portion 7 in an inner welding process of the production line. In the manufacturing method exemplified above, since the left and right side edge portions 3 and 5 are each subjected to roll forming in order, it is possible to individually respond to a change in the specification of roll forming of each part, and the flexibility as a manufacturing line is not provided. Although excellent, the proportion of the roll forming step in the production line becomes longer, which requires a larger installation area of the production line, and requires more production time. Therefore, in this example, the roll forming of both side edges 3, 5 was performed simultaneously so as not to hinder the inner welding process.

The original sheet 10 unwound from the uncoiler 12 is
In the pre-roll forming step, as shown in FIG. 12, both side edges 3, 5 are simultaneously bent. At this time,
The one side edge 5 forming the reinforcing rib 8 is folded until the plane portion 7 is brought into contact with the bumper front surface 4 in the same manner as the above-described manufacturing method, but the other side edge 3 is stopped during molding. As shown in FIG. 13 (comparing and comparing FIG. 9 with FIG. 12), welding (roll spot welding) to the flat portion 7 is performed in the subsequent inner welding step. As described above, by providing a process in which the roll forming of the side edges 3 and 5 progresses at the same time, even if only halfway, the roll forming process after bending the rest of the other side edge 3 is shortened (see FIG. 5 and FIG. 5). As a result, the production line and the production time can be shortened.

Since the flat portion and the front surface of the bumper need to be joined, roll forming is always required twice. In the present invention, the roll forming on both side edges is performed as an inner roll forming step and an outer roll forming step in this order. A manufacturing method and a manufacturing method in which the roll forming of both side edges is partially performed at the same time as a pre-roll forming step and a post-roll forming step are presented. As described above, it is better to divide the degree of freedom into inner and outer roll forming steps, and it is more preferable to divide the degree of freedom into front and rear roll forming from the viewpoint of reducing the installation area and shortening the manufacturing time. In either case, the same reinforcing material can be obtained as a product, so it is preferable to appropriately select both materials and construct a production line.

[0022]

The bumper reinforcing material of the present invention is a closed-section reinforcing material formed by bending one original plate, and has an advantage that it can be easily manufactured by a continuous manufacturing line called roll forming. In addition, the front surface of the bumper and the rear surface of the bumper are connected by a bumper reinforcing material, and the resulting product has high structural strength. This improvement in structural strength is not simply due to the presence of the reinforcing ribs, but the joining of the front surface of the bumper and the reinforcing ribs is made by integrally joining the flat portion from the side edge to the folded edge to the front surface of the bumper. It is very big.

The improvement of the structural strength by the reinforcing ribs appears as an increase in the second moment of area of the reinforcing material. In addition, the joining of the flat portion to the front surface of the bumper prevents buckling of the reinforcing material, and generally makes it possible to provide a stronger reinforcing material. This means that a thinner base plate can be used, which realizes a reduction in the weight of the reinforcing material and a reduction in raw material costs. The presence of such reinforcing ribs results in the omission of another member such as a bulkhead in order to increase the structural strength, so that the number of parts as a reinforcing material is reduced and the number of assembling steps is reduced.

In addition, the joining of the reinforcing rib and the front surface of the bumper using the flat portion enables a welding method suitable for a continuous production line called roll spot welding. this is,
This means that the welding means can be selected together with the selection of the combination of the roll forming steps, thereby enabling the construction of a production line with a higher degree of freedom. As described above, the reinforcing material of the present invention has an effect of improving structural strength as a product and reducing equipment costs, manufacturing costs, and labor or man-hours required for manufacturing.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a basic appearance of a reinforcing material to which the present invention is applied.

FIG. 2 is a left side view of the reinforcing member.

FIG. 3 is a left side view when the reinforcing member is used upside down.

FIG. 4 is a left side view corresponding to FIG. 2 of a reinforcing member overlapped with a folding edge portion and joined to the other side edge portion.

FIG. 5 is a configuration diagram showing a production line of the reinforcing member of FIG. 1;

FIG. 6 is a perspective view showing an original sheet unwound from an uncoiler.

FIG. 7 is a perspective view showing a tubular intermediate product after an inner roll forming step.

FIG. 8 is a perspective view showing a tubular intermediate product in the middle of performing a roll spot welding on a flat part in the inner welding step.

FIG. 9 is a perspective view showing a tubular intermediate product after the inner roll forming step.

FIG. 10 is a perspective view showing a tubular intermediate product in the middle of laser welding the other side edge portion in the outer welding step.

11 is a configuration diagram illustrating another example of a production line of the reinforcing member of FIG. 1.

FIG. 12 is a perspective view showing a tubular intermediate product in a pre-roll forming step.

FIG. 13 is a perspective view showing a tubular intermediate product in the middle of performing a roll spot welding on a flat portion in the inner welding step.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bumper reinforcement 2 Folding edge 3 The other side edge 4 Bumper front surface 5 One side edge 6 Folding edge 7 Flat part 8 Reinforcement rib 9 Bumper back surface 10 Original plate 11 Tubular intermediate product 12 Uncoiler 13 Roll spot welding machine 14 Laser welding machine

Claims (3)

[Claims] 1. A bumper reinforcing material obtained by rolling an original plate into a tubular shape, wherein one side edge of the original plate is bent in the order of a folded edge portion of a valley and a folded edge portion of a mountain, and from the side edge to the folded edge portion. A bumper reinforcing material characterized in that the flat part of the original plate is joined to the front surface of the bumper in a contact state, and the other side edge of the original plate is joined near the folded edge. 2. A method of manufacturing a tubular bumper reinforcing material, comprising: bending one side edge of a continuously fed base plate in the order of a folded edge of a valley and a folded edge of a mountain; An inner roll forming step of bringing a flat portion up to the edge into contact with the front surface of the bumper, an inner welding process of joining the flat portion and the front surface of the bumper continuously or intermittently, and placing the other side edge near the folding edge. A method of manufacturing a bumper reinforcing material, comprising sequentially performing an outer roll forming step of forming a closed cross-section and an outer welding step of continuously joining the other side edge and the vicinity of a folding edge. 3. A method for producing a tubular bumper reinforcing material, wherein a side edge of a valley and a ridge of a mountain are bent in the order of a folded edge of a valley and a folded edge of a mountain on a continuously fed base plate. At the same time that the flat portion up to the edge is brought into contact with the front surface of the bumper, the other side edge is bent and the pre-roll forming step to approach the folded edge portion, and the flat portion and the front surface of the bumper are continuously or intermittently performed. An inner welding step for joining, a roll forming step for forming a closed cross section by addressing the other side edge near the folding edge, and an outer joining for continuously joining the other side edge and the vicinity of the folding edge. A method for manufacturing a bumper reinforcing material, comprising sequentially performing a welding process.