JP3413404B2 - Method of manufacturing guard beam for automobile door - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a guard beam for increasing the strength of an automobile door, and more particularly to a pipe-shaped guide beam formed by pressing a magnesium sheet suitable for recycling. And a method for producing the same. 2. Description of the Related Art Recently, a high degree of safety has been required for automobiles, and airbags, seat belts, and the like are provided, and reinforcement of doors against collision from the side of the automobile is required. . On the other hand, automobile doors are required to be lightened because they frequently open and close when getting on and off, and iron plates used for automobile doors are formed by pressing a thin plate. To make up for the lack of strength of this door,
Various reinforcing members are mounted inside the door. [0003] If a thin iron plate is directly attached to the inside of the door as a reinforcing member and doubled, the strength is insufficient.
A convex portion such as a reinforcing rib having an arbitrary shape is formed in a direction perpendicular to the longitudinal direction of the iron plate to reinforce the member. However, since it is difficult for a reinforcing member formed of a thin iron plate to withstand an impact due to an accident, for example, as shown in FIG. 1, a reinforcing member 3 formed of a pipe member having relatively high strength against side collisions is used. Is mounted inside the door. [0004] As shown in Figs. 1 and 3, the reinforcing member 3 is mounted inside the door 1 for a vehicle in the horizontal direction, and the iron plate constituting the door projects inward (toward the seat) in the event of an accident. To prevent passenger injuries. As a member used for the reinforcing member 3, an iron material is generally used in terms of strength, ease of molding, economy, and the like. However, since iron has a specific gravity of 7.87 and a weight, it is formed using a thin iron plate in order to reduce the weight, so that the strength necessarily decreases. As shown in FIG. 2, plate-like mounting pieces 3b and 3c formed separately from the reinforcing portion main body 3a are fixed to both ends of the reinforcing member 3 by welding or the like, and the mounting pieces 3b and 3c are attached. Since the reinforcing member 3 is fixed to the inside of the vehicle door 1 by bolts, nuts, welding, or the like, and the mounting pieces 3b, 3c must be welded to both ends of the reinforcing portion main body 3a formed in a pipe shape, respectively. There is a problem that it takes time to manufacture. On the other hand, when an automobile using the reinforcing member 3 made of an iron material is scrapped and scrapped, even if recycling is encouraged for resource conservation, the iron product is rusted and corroded and is heavy. The handling is troublesome, and the collection work and transportation are very costly. In addition, since the cost obtained by resource recovery is low and the recycling effect is low, recycling has not spread, and it has been difficult to achieve the object of increasing the resource recovery rate and reducing waste. Therefore, the use of magnesium as a substitute for iron, which cannot be expected to have a recycling effect as a component of automobile parts, has been called for. Magnesium has a specific gravity of 1.74, about 1/4 that of iron, and is lighter than iron. Its strength is increased by press hardening when it is repeatedly pressed, and it can surpass the reinforcing member made of iron pipe. It will have inferior strength. Magnesium material has advantages such as higher recovery price as scrap than iron material and extremely useful for resource recycling. [0008] Magnesium materials have the above-mentioned advantages. However, since the plate material has low viscosity, the stretching force during processing is small, and the repulsive force against bending is strong. It is difficult to commercialize by processing. In addition, during press working, the sheet material does not extend uniformly and tends to crack, and it is difficult to stabilize it to a certain shape after press working, so press work requires the skills and labor of skilled workers and is inefficient. And other problems. Therefore, the present invention is the lightest among structural metal materials and has both recycling and recycling characteristics.
An object of the present invention is to provide a method for manufacturing a guard beam for reinforcing automobile doors using a magnesium material which is excellent in environmental compatibility and is an energy saving material. [0010] In order to solve the above-mentioned problems, the present invention provides a first convex mold having a tip formed in an arc-shaped portion,
U having the same thickness as the magnesium thin plate between the convex die
The intermediate portion of the magnesium thin plate is formed by pressing at least once with a slightly weak force using a first mold including a first concave mold having an inner surface having a concave portion with a character-shaped gap. A first step of bending into a U-shape, and an upper flat surface for contact with the lower end of an open-open taper portion provided on both sides of an upper semicircular portion provided with a magnesium thin plate bent into a U-shape inward. A second convex mold having an open-open shape having a lower flat surface with which the upper flat surface abuts on both sides of a lower semicircular portion provided in an upward direction in pairs with the convex mold. The U-shaped magnesium thin plate is formed into a substantially cylindrical pipe by at least one or more press workings with a slightly weak force using a second mold including a second recessed metal having a downwardly inclined portion. A second step of forming the pipe-shaped part, and a third convex mold having a semicircular part facing the pipe-shaped part downward. The inner diameter of the third concave mold provided with an upward semicircular portion that forms a pair with the convex mold is slightly smaller than the inner diameter of the upper semicircular portion and the lower semicircular portion of the second mold. And a third step of joining the joints of the pipe-shaped portions to each other by press working at least once or more with a slightly weak force using a third mold. As described above, the first mold for the first step which is a preliminary step, the second mold for the second step which is a molding step, and the third mold for the third step which is a finishing step. By performing press working several times with slightly weak force while using different molds, it is possible to obtain a guard beam that has lightweight and hard properties by using pressure hardening of a magnesium thin plate and has recycling characteristics. . DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described with reference to the drawings. FIG. 4 is a perspective view of a guard beam, and FIG.
4 is a cross-sectional view taken along the line AA of FIG. 4, FIG. 6 is a cross-sectional view of a main part in a state where a pipe-shaped portion is formed in a double structure, and FIG. 7 is a perspective view of a rectangular aluminum thin plate forming a guard beam. The guard beam 9 is formed into a thin plate (hereinafter referred to as a magnesium thin plate) 10 made of a magnesium alloy having a specific gravity of 1.74, for example, a plate having a thickness of 1.5 to 3 mm, preferably about 2 mm. A pipe-like portion 15 is formed in an intermediate portion 13 of the thin plate 10. At both ends of the pipe-like portion 15, plate-like mounting portions 10a, 10a are integrally formed. A reinforced structure 10b formed by bending a pipe-like portion 15 and mounting portions 10a, 10a integrally provided at both ends of the pipe-like portion with curved ridges to form a continuous reinforcing rib. Is formed integrally, the strength of the continuous portion between the pipe-shaped portion 15 and the mounting piece 10a is further enhanced, and the work of fixing the mounting member 10a to the pipe-shaped portion 15 can be eliminated. In order to further reinforce the pipe-like portion 15, a reinforcing pipe 15a made of a thin magnesium plate having a slightly smaller diameter is inserted and doubled (FIG. 6) or tripled (not shown). The strength can be increased without significantly increasing the weight. Next, a method of manufacturing the guard beam 9 will be described. The guard beam 9 is formed by pressing a magnesium thin plate 10.
If the pipe-shaped portion 15 is formed by pressing with a large force at once and deforming the pipe-shaped portion 15, the thickness of the plate becomes uneven or cracks occur due to the properties of the magnesium material. Therefore, in order to prevent the cracks and the like, it is preferable to perform the pressing with a slightly weak force in several steps while deforming little by little. As shown in FIG. 7, a thin magnesium plate 10 for forming the guard beam 9 is formed by punching or cutting a flat plate to form a substantially rectangular plate material, and has both end surfaces 11, 11 as short sides and a long side. Both end faces 12, 12
Does not have a protruding portion or a concave portion having a unique shape, and is simply formed in a straight line, so that press working can be easily performed. In the first step, as shown in FIG. 8, a magnesium thin plate is pressed a plurality of times by a first
Form in the shape of a letter. In this case, when the sheet is pressed with a strong force, the thin plate is broken. Therefore, it is preferable to perform the pressing in a plurality of times with a slightly weak force. The first mold 21 includes a first convex mold 21a having an arc-shaped tip, and a first concave mold 21b having a U-shaped gap between the first mold 21a and the convex mold. The middle part 13 of the magnesium sheet 10 shown in FIG.
Is pressed from above to form a U-shape. This first
The U-shaped gap existing between the convex mold 21a and the concave mold 21b is a space having a size substantially equal to the thickness of the magnesium thin plate. An intermediate part is accommodated. Since the magnesium sheet has a strong repulsive force, the upper end of the sheet is not formed in a U-shape but formed substantially in a V-shape in one press working, so that the work in the second step cannot be performed as it is. Therefore, the first convex mold 21a
Alternatively, the first concave mold 21b is bent in a U-shape by repeatedly performing press working while appropriately adjusting the position of the first concave mold 21b. In the second step, as shown in FIGS. 9 and 10, the intermediate portion 13 formed in a U-shaped cross section is connected to the second mold 2 forming a pair.
5 and press working a plurality of times with slightly weak force to prevent cracks and the like from occurring in the thin plate.
5 is formed. The second mold 25 is used for centering the pipe-shaped portion when the intermediate portion 13 formed in the U-shape is rounded to form the pipe-shaped portion 15. An outwardly open tapered portion 27a is provided on both sides of an upper semicircular portion 26a, and a downward slope matching the tapered portion 27a on both sides of a lower semicircular portion 26b of a second concave mold 25b which is the other mold. , The outwardly open inclined portions 27b are respectively formed. In the case of press working with the second convex mold 25a and the concave mold 25b constituting the pair of second molds 25,
The outwardly opening tapered portion 27a and the inclined portion 27b are formed as shown in FIG.
0, the center of the downwardly provided upper semicircular portion 26a and the downwardly provided lower semicircular portion 26b is fixed to prevent the axial center deviation of the mold, and the entire pipe-like portion 15 is formed. Can be formed in a cylindrical shape. This second convex mold 2
An upper flat surface 28a for contact is formed at the lower end of the tapered portion 27a of 5a, and the upper flat surface 28a contacts the lower end of the inclined portion 27b of the second concave mold 25b. A lower flat surface 28b is formed. In the second step, a pipe-like portion 15 is formed in the intermediate portion 13 of the magnesium thin plate. When the pipe-like portion is removed from the second mold 25, the repulsive force of the magnesium thin plate causes the pipe-like portion 15 to be formed. The joint 18 has an open shape (FIG. 11). Since the guard beam in which the joint 18 of the pipe-shaped portion 15 is open is not cylindrical in cross section, when used as a guard beam for an automobile door, the pipe-shaped portion has weak strength against impact from a right angle direction. . In the third step, as shown in FIGS.
The joint 18 of the pipe-shaped portion 15 formed in a cylindrical shape is
They are joined by a mold 30 to form a substantially cylindrical cross section. The third molds 30 each include a third convex mold 30 having a substantially semicircular cross section.
a and a third concave mold 30b, and the inner diameter of the downward semicircular portion 31a of the convex mold 30a and the upward semicircular portion 31b of the concave mold 30b is equal to the semicircle of the second mold 25. It is formed slightly smaller than the inner diameter of the portion 26. The position of the pipe-shaped part 15 housed in the semicircular parts 31a and 31b of the third mold 30 is adjusted, and the press working is performed a plurality of times with slightly weak force. Thereby, the repulsive force of the magnesium thin plate 10 is suppressed, and the pipe-like portion 15 in which the joints 18 are joined to each other can be formed. In the first to third steps, the pipe-shaped portion 15 of the magnesium thin plate 10 is pressurized and hardened by repeating press working, whereby a strong and high-strength guard beam 9 can be formed. The guard beam 9 manufactured by using the magnesium thin plate 10 has a specific gravity of magnesium of 1.74 as compared with the specific gravity of iron of 7.87, and can be formed with a weight of about ４ of the iron material. it can. When this guard beam 9 is mounted inside the doors of an automobile, that is, two front doors and two rear doors, a total of four guard beams made of magnesium and one guard beam made of iron are provided. The weight is substantially the same, and the use of magnesium material has the advantage that the weight of the guard beam can be reduced, the vehicle weight can be reduced, and the performance of the engine can be further improved. According to the present invention, three types of magnesium thin plates, which are difficult to press, are pressed in a plurality of times by using different molds in different pairs to prevent folding spots and cracks. It is possible to form a guard beam with excellent pressure hardening properties, and it is possible to press the magnesium thin plate to form the pipe part and the mounting piece integrally, so that it is lightweight, strong, and safe. It also has the advantage of being excellent in environmental compatibility, having both recycling characteristics and recycling characteristics.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory view showing a state where a guard beam is mounted inside an automobile door. FIG. 2 is a front view showing a guard beam made of a conventional pipe member. FIG. 3 is a sectional view of a main part showing a state in which a guard beam is attached to the inside of an outer surface plate and an inner surface plate of an automobile door. FIG. 4 is a perspective view of a guard beam according to the present invention. FIG. 5 is a sectional view taken along line AA of FIG. 4; FIG. 6 is a sectional view in the same direction as FIG. 5 showing another embodiment. FIG. 7 is a perspective view of a magnesium thin plate showing a material forming a guard beam according to the present invention. FIG. 8 is a sectional view showing a state in which an intermediate portion of a magnesium thin plate is pressed into a substantially U-shaped section by a first mold. FIG. 9 is a cross-sectional view showing a state before the upper portion of the magnesium thin plate pressed into a U-shaped cross section is pressed by a second mold. FIG. 10 is a cross-sectional view showing a state where a pipe-shaped portion is formed by pressing with a first mold and a second mold. FIG. 11 is a cross-sectional view of a pipe-shaped portion in a state where seams are opened by restoring force after press working with a second mold. FIG. 12 is a sectional view of a state before the pipe-shaped portion is pressed by a third mold. FIG. 13 is a sectional view showing a state where the pipe-shaped portion is pressed by a third mold. FIG. 14 is a cross-sectional view of a pipe-shaped portion in a state where seams are joined. [Description of Signs] 9 Guard beam 10 Magnesium thin plate 13 Intermediate part 15 Pipe-shaped part 18 Joint 21 First mold 21a First convex mold 21b First concave mold 25 Second mold 25a Second convex Mold 25b Second concave mold 26a Upper semicircular portion 26b Lower semicircular portion 27a Tapered portion 27b Inclined portion 28a Upper flat surface 28b Lower flat surface 30 Third die 30a Third convex die 30b Third concave Mold 31a semicircular part 31b semicircular part

Claims (1)

(57) Claims 1. A magnesium thin plate (1) is provided between a first convex mold (21a) having an arc-shaped tip and a convex mold.
Using a first mold (21) consisting of a first concave mold (21b) having a U-shaped gap having the same plate thickness as that of (0) and having a concave portion on the inner surface with a slight force, An intermediate portion (13) of the magnesium sheet by at least one press working
And a first step of bending the U-shaped magnesium sheet into a U-shape. At the lower end of an open-open tapered part (27a) provided on both sides of an upper semicircular part (26a) having a U-shaped bent magnesium thin plate facing downward. Upper flat surface for contact (28a)
The upper flat surface (28a) abuts on both sides of a second convex mold (25a) having a lower semicircular portion (26b) provided inside and facing upward in a pair with the convex mold. Lower flat surface (28
An open-ended downwardly sloped portion provided with b) (27b)
The U-shaped magnesium thin plate is formed into a substantially cylindrical shape by pressing at least once with a slightly weak force using a second mold (25) including a second concave mold (25b) formed with A second step of forming the pipe-shaped part (15), a third convex mold (30a) having a semicircular part (31a) with the pipe-shaped part facing downward, and an upward facing pair with the convex mold A third metal die having an inner diameter with the third concave mold (30b) provided with the semicircular part (31b) is slightly smaller than the inner diameter of the upper semicircular part and the lower semicircular part of the second die. A third step of joining the joints (18) of the pipe-shaped portions to each other by pressing at least once using a mold (30) with a slightly weak force. Production method.