JP2001239835A - Guard beam for automobile door and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a guard beam formed with a pressed magnesium thin plate adaptable for recycling for improving the strength of an automobile door. SOLUTION: The automobile door reinforced by longitudinally mounting a reinforcing member in a space between an outside plate and an inside plate for the door comprises a pipe portion 15 provided at a middle portion of the approximately rectangular magnesium thin plate which has hardened quality with repetitive pressing and mounting members 10a, 10a integrally provided at both ends thereof. Curved reinforced structural portions 10b are provided at both edges of a connection connecting both ends of the pipe portion and both ends of the flat mounting member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a guard beam for enhancing 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 of manufacturing the same.

[0002]

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. In addition, there is a demand for reinforcement of doors against collisions from the side of the vehicle, that is, from the side. on the other hand,
2. Description of the Related Art Automobile doors are frequently opened and closed when getting on and off, and thus are required to be lightweight. As an iron plate used for an automobile door, a steel plate formed by pressing a thin plate is used to reduce the weight. Therefore, in order to compensate for the insufficient strength of the door, various reinforcing members are mounted inside the door.

[0003] As a reinforcing member, if a thin iron plate is attached to the inside of the door as it is and doubled, the strength is insufficient. For example, a reinforcing rib having an arbitrary shape in a direction perpendicular to the longitudinal direction of the iron plate. Are formed to reinforce the member. However, since it is difficult for a reinforcing member made of a thin iron plate to withstand the impact of an accident, for example,
As shown in FIG. 1, a reinforcing member 3 formed of a pipe member having relatively high strength against side collision is mounted inside the door.

As shown in FIG. 3, the reinforcing member 3 is mounted horizontally inside the door 1 for an automobile, and in the event of an accident, the iron plate forming the door is turned inward (toward the seat).
This prevents passengers from being injured by protruding into the vehicle.

As the member used for the reinforcing member 3, an iron material is generally used from the viewpoints of strength, easiness of molding and economy. However, since iron has a specific gravity of 7.87 and is heavy, it is formed using a thin iron plate for weight reduction. Therefore, the strength necessarily decreases.

As shown in FIG. 2, the reinforcing member 3 is attached to the reinforcing member 3 by welding flat plate-like mounting pieces 3b and 3c formed on both ends of the reinforcing member 3 with members different from the reinforcing member main body 3a. The mounting pieces 3b and 3c are fixed to the interior of the door 1 for automobiles by bolts, nuts, welding, or the like. The reinforcing member 3 has a problem in that the mounting pieces 3b and 3c have to be welded to both ends of the reinforcing portion main body 3a formed in a pipe shape, respectively, so 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, the iron product is rusted and corroded or heavy even if recycling for resource conservation is encouraged. Therefore, the handling is troublesome, and the collection work and transportation are very costly. Moreover,
The cost obtained by resource recovery is low, and the recycling effect is low, so that recycling has not spread, and it has been difficult to achieve the purpose 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, which is about 1/4 the weight of iron, which is lighter.
Magnesium is extremely hardened by pressure hardening when it is molded while repeating press working, and has a strength not inferior to that of a reinforcing member formed of an iron pipe. Magnesium material has a higher recovery price as scrap than iron material, and is extremely useful for resource recycling. It has many advantages.

[0009]

The magnesium material has the above-mentioned advantages. However, since the plate material has a low viscosity, the elongation at the time of processing is small, and the repulsive force against bending is strong. Have difficulty. Also,
During press working, the sheet material does not stretch uniformly, it is easy to crack, and it is difficult to stabilize it to a certain shape after press working, so the press work requires the skill and labor of skilled workers, so it is inefficient There were many problems.

Therefore, the present invention provides a guard for reinforcing a door of an automobile using a magnesium material which is the lightest among structural metal materials, has both recycling and recycling characteristics, is excellent in environmental compatibility and is also an energy-saving material. It is an object to provide a beam and a method for manufacturing the beam.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to an automotive vehicle in which a reinforcing member is attached to a space provided between an outer plate and an inner plate of a door by attaching a reinforcing member in the front-rear direction. In the door, press work is repeated on a substantially rectangular magnesium thin plate to repeatedly pressurize and harden the material, and at both ends of a pipe-shaped portion provided on an intermediate member of the magnesium thin plate,
It is characterized in that the mounting pieces are provided integrally.

Further, the present invention is characterized in that both edges of a connecting portion for connecting both ends of the pipe-shaped portion and ends of the mounting piece are bent in a curved shape to form a reinforcing structure. Therefore, a light and strong guard beam can be mounted inside the automobile door without increasing the weight of the vehicle.

According to a second aspect of the present invention, there is provided a first step of bending a substantially rectangular magnesium sheet into a U-shaped cross section by at least one press working with a first mold, and a step of bending the magnesium sheet in the first step. A second step of forming a pipe-like portion having a substantially cylindrical cross section by at least one press working with a second mold; A third step of joining seams together by press working more than once.

In the first mold according to the present invention, a U-shaped gap having the same thickness as the magnesium thin plate is provided between the convex mold and the convex mold having an arc-shaped tip. The inner surface is formed of a concave mold having a concave portion.
Further, the second mold comprises a convex mold and a concave mold,
An outwardly-opening tapered portion is provided on both sides of an upper semicircular portion provided downward inside the convex mold, and a lower semicircular portion provided upwardly inside the concave mold, and an open-opened shape is formed on both sides. It is characterized by forming a downward slope. Furthermore, the third
The mold has a convex mold provided with a downward semicircular portion, and an inner diameter of an upward semicircular portion forming a pair with the convex mold is formed to be slightly smaller than an inner diameter of the second mold. It is characterized by becoming.

[0015]

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, and FIG. It is principal part sectional drawing in the state where the pipe-shaped part was formed in the double structure. As described above, the guard beam 9 is a thin plate (hereinafter, referred to as a magnesium thin plate) 1 made of a magnesium alloy having a specific gravity of 1.74.
0, for example, the plate thickness is 1.5 to 3 mm, preferably about 2 m
m, and a pipe-like portion 15 is formed in an intermediate portion of the magnesium thin plate 10. At both ends of the pipe-like portion 15, plate-like attachment portions 10a, 10a are integrally formed.

A pipe-shaped portion 15 and flat plate-shaped mounting pieces 10a, 10a provided integrally at both ends of the pipe-shaped portion.
Are integrally formed by the reinforcing structure portion 10b having a curved ridge line, so that the pipe-shaped portion 15 and the mounting portion piece 10a
And the strength of the continuous portion can be further enhanced. Therefore, the operation of fixing the mounting member 10a to the pipe-like portion 15 can be omitted.

Both ends of the pipe 15 and the mounting piece 10a
The reinforcing structure portion 10b, which is a continuous portion with the end portion, is bent in a curved shape to form reinforcing ribs continuously, thereby further strengthening the strength of the continuous portion between the pipe-shaped portion 15 and the mounting piece 10a. are doing.

Further, when it is necessary to reinforce the pipe-like portion 15, a reinforcing pipe 15a made of a magnesium sheet having a slightly smaller diameter may be inserted to form a double (FIG. 6), or By forming three layers (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 it is attempted to form the pipe-shaped portion 15 by applying a large force at a time and pressing and deforming it to a large extent, the thickness of the plate becomes non-uniform 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. Both end faces 12, 12
Is not provided with a protruding portion or a concave portion having a unique shape, and can be relatively easily performed even when a press process is performed by simply forming a linear shape.

In the first step, as shown in FIG. 8, the magnesium thin plate 10 is pressed once or a plurality of times by a first mold 21 to form a U-shaped cross section. In this case, if the sheet is pressed with a strong force, the thin plate is broken. Therefore, it is preferable to perform the pressing with at least one or a plurality of times with a slightly weak force. The first mold 21 includes a convex mold 21a having an arc-shaped tip and a concave mold 21b having a U-shaped gap between the convex mold 21a and the magnesium mold shown in FIG. The intermediate portion 13 of the thin plate 10 is pressed from above with respect to the axial direction X to form a U-shaped cross section.

In this case, the U-shaped gap provided between the convex mold 21a and the concave mold 21b is a space having dimensions substantially equal to the thickness of the magnesium thin plate.
A magnesium thin plate is accommodated in the gap.

Since the magnesium thin plate 10 has a high repulsive force, the upper end spreads right and left so as to become substantially V-shaped instead of U-shaped in a single press working. Can not do. Therefore, by repeatedly performing press working while appropriately adjusting the position of the convex mold 21a or the concave mold 21b, the convex mold 21a or the concave mold 21b is curved in a U-shape.

In the second step, as shown in FIGS. 9 and 10, the intermediate member 13 formed in a U-shaped cross section is divided at least once or a plurality of times by a pair of second molds 25 with slightly weak force. Then, the pipe-like portion 15 is formed by press working so as not to cause cracks or the like in the thin plate. When the intermediate member 13 formed in a U-shape is rounded to form the pipe-shaped portion 15, the second mold 25 centers the pipe-shaped portion. Are provided on both sides thereof, and open slopes 27b are formed on both sides of the lower semicircular portion 26b of the other concave mold 25b with a downward slope matching the taper portion 27a. is there.

When pressing is performed with a pair of the convex mold 25a and the concave mold 25b, the tapered portion 27a and the inclined portion 27
b are joined to each other, the center of the downwardly provided upper semicircular portion 26a and the downwardly provided lower semicircular portion 26b is fixed to prevent the center of the shaft from shifting, and the entire pipe-like portion 15 is formed into a cylindrical shape. can do. An upper flat surface 28a for contact is formed at the lower end of the tapered portion 27 of the convex mold 25a, and the flat surface 28a is formed at the lower end of the inclined portion 27b of the concave mold 25b.
And a lower flat surface 28b for contact.

In the second step, the magnesium sheet 10
A pipe-shaped part 15 is formed on the intermediate member 13 of FIG.
The joint 18 of the pipe-shaped portion 15 is opened due to the repulsive force of the (1) (FIG. 11).

Since the cross section of the guard beam with the joint 18 of the pipe portion 15 open is not cylindrical, when used as a guard beam for an automobile door, the pipe portion is protected from impact from a right angle direction. Strength is weak.

In the third step, as shown in FIGS.
The joint 18 of the pipe-shaped portion 15 formed in a cylindrical shape is joined by a third mold 30 to form a substantially cylindrical cross section. Third mold 30
Consists of a convex mold 30a and a concave mold 30b each having a substantially semicircular cross section. The inner diameters of the semicircular portions 31a and 31b of the convex mold 30a and the concave mold 30b are the same as those of the second mold. It is formed slightly smaller than the inner diameter of the semicircular portion 26 of the mold 25.

The semicircular portions 31a, 31 of the third mold 30
b, while appropriately adjusting the position of the pipe-shaped portion 15, by performing press working at least once or a plurality of times with a slightly weak force to suppress the repulsive force of the magnesium thin plate 10 and join the joints 18 to each other. It is possible to form the pipe-shaped portion 15 in a state where the pipe-shaped portion 15 is made to be in a state where the pipe-shaped portion 15 is formed.

In the first to third steps, the magnesium thin plate 10 is repeatedly compressed, that is, pressed, so that the pipe-shaped portion 15 is pressurized and hardened, and the strong and strong guard beam 9 is formed. Can be formed.

At both ends of the pipe-like portion 15, as shown in FIG. 4, flat mounting portions 10a, 10a are integrally formed via a reinforcing structure portion 10b having a curved ridge line to form a guard beam. 9 is formed.

The pipe-shaped part 15 of the guard beam 9
Plate-shaped mounting piece 1 located at both ends of the pipe-shaped part
The reinforcement structure 10b connecting the pipes 0a and 10a is curved in an extension of the joint of the pipes to form reinforcement ribs, so that the pipe-like portion 15 and the mounting piece 1 are joined together.
The strength of the continuous portion with 0a can be further enhanced.

In addition, since the mounting portions 10a and 10a are integrally formed at both ends of the pipe-shaped portion 15 via the reinforcing structure portion 10b, the work of fixing the mounting member 10a to the pipe-shaped portion 15 becomes unnecessary. The manufacturing process can be simplified, and the cost can be reduced.

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 / of the iron material. it can. When this guard beam 9 is mounted inside a door of an automobile, that is, a total of four doors, two front doors and two rear doors, four guard beams made of magnesium material and one guard beam made of iron material are used. The weight is almost the same. As described above, since the weight of the guard beam can be reduced by using the magnesium material,
There is also an advantage that the performance of the engine can be further improved by reducing the vehicle weight.

[0035]

According to the guard beam of the present invention, the magnesium thin plate is pressed to form the pipe-shaped portion and the mounting portion piece integrally, so that the guard beam is lightweight, strong, and can have high safety. In addition, it has the advantage of being excellent in environmental compatibility as well as having recycling characteristics and recycling characteristics. By pressing a magnesium thin plate, which is difficult to press, once or a plurality of times in different stages, it is possible to prevent folds and cracks, and to form a guard beam excellent in pressurization curability.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a state in which an inner plate of an automobile door is removed, showing a state in which a conventional guard beam is attached.

FIG. 2 is a front view showing a guard beam made of a conventional pipe member.

FIG. 3 is a cross-sectional view of a main part showing a state where a guard beam is mounted inside an outer plate and an inner 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 cross-sectional view showing a state in which an intermediate member of a magnesium thin plate is pressed into a substantially U-shaped cross section by a first die.

FIG. 9 is a cross-sectional view showing a state before an upper portion of a 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.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Automobile door 3 Reinforcement member 3a Pipe-shaped part 3b Mounting part 3c Mounting part 9 Guard beam 10 Magnesium thin plate 10a Mounting part 10b Reinforcement structure 13 Intermediate part 15 Pipe-shaped part 18 Joint 21 First mold 21a Convex Mold 21b Concave mold 25 Second mold 25a Convex mold 25b Concave mold 26a Semicircle 26b Semicircle 27a Taper 27b Inclined part 30 Third mold 30a Convex mold 30b Concave mold 31a Semicircle Part 31b semicircular part

Claims (6)

[Claims] 1. An automobile door in which a reinforcing member is attached in a front-rear direction to a space provided between an outer plate and an inner plate of a door to reinforce the door. A guard beam for an automobile door, wherein a mounting member is integrally provided at both ends of a pipe-shaped portion provided on an intermediate member of the magnesium thin plate by hardening the material. 2. The reinforcing structure according to claim 1, wherein both edges of a connecting portion for connecting both ends of the pipe-shaped portion and ends of the mounting piece are bent in a curved shape. Guard beams for automobile doors. 3. A first step in which a substantially rectangular magnesium thin plate is bent into a U-shaped cross section by at least one press working with a first mold, and a magnesium thin plate bent in the first step is bent into a second metal. Type
A second step of forming a pipe having a substantially cylindrical cross-section by at least one or more press workings, and joining the pipe-shaped part having a substantially cylindrical cross-section with a third mold by at least one or more press workings A method of manufacturing a guard beam for an automobile door, comprising a third step of joining eyes together. 4. The first mold has a U-shaped gap having the same thickness as the magnesium thin plate between the convex mold and the convex mold when the tip is formed in an arc-shaped portion. 4. The method according to claim 3, wherein the inner surface comprises a concave mold having a concave portion. 5. The second mold comprises a convex mold and a concave mold, and has an open taper portion on both sides of an upper semicircular portion provided downward inside the convex mold, 4. A guard beam for an automobile door according to claim 3, wherein a lower semicircular portion provided upward in the interior of the concave mold, and an inclined portion having an open downward slope are formed on both sides. Production method. 6. The third mold has a convex mold provided with a downward semicircular portion, and an inner diameter of an upward semicircular portion which forms a pair with the convex mold and has an inner diameter of the second mold. 4. The method for manufacturing a guard beam for an automobile door according to claim 3, wherein the diameter is formed to be slightly smaller than the inner diameter of the guard beam.