JPH0751738A - Extrusion molding material - Google Patents

Abstract

PURPOSE:To obtain an extrusion molding material made of metal such as aluminum, which is provided with a shape superior in the bendability to suppress the generation of wrinkles in the ribs and also to eliminate cracks of the face plate, in bending by using a core. CONSTITUTION:In an extrusion molding material in which a cylindrical face plate 11 and at least one reinforcing rib 12 for connecting in between the face plates 11 are integrally extruded, in which one of the intersected parts 13 forming a T-shape with the face plate 11 and the rib 12 receives an tensile load, and in which the other intersected part is bent in the direction of receiving a compressive load; at least the thickness t1 of the face plate 11 in the T-shaped intersected part 13 and the thickness t2 of the rib 12 are t1/t2>=1.1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal extrusion mold material used for automobile bumper materials, and more particularly to an extrusion mold material having a shape suitable for bending.

[0002]

2. Description of the Related Art In recent years, due to demands for weight reduction of vehicle bodies,
BACKGROUND ART Extruded mold materials made of aluminum or aluminum alloy are being widely used as bumper materials, side beams, bowl hooves and the like of automobiles. This extruded mold material has a so-called date shape shown in FIG. 4 and a mark shape shown in FIG.
A tubular face plate 1 having the external shape of the bumper material and a rib 2 for reinforcing the face plate 1 inside the face plate 1 are integrally extruded.

As shown in FIGS. 4 and 5, in this extruded shape member, one of the intersections 3 and 3 which are generally T-shaped between the face plate 1 and the rib 2 is pulled according to the shape of the bumper or the like. Bending is performed in the direction in which the load is applied and the other receives the compressive load. By the way, when performing such bending, first insert a metal core into the hollow portion of the extruded mold material, and then perform the bending process in the above-described direction so that the extruded mold material has a desired product shape. ing.

[0004]

However, when attempting to bend the above-mentioned extrusion die material, particularly in the case of an extrusion die material made of aluminum or aluminum alloy, even when the core is inserted and the above-mentioned bending operation is performed, the extruded die material is bent. Due to the tensile stress and the compressive stress applied, there are problems that wrinkles are generated in the ribs 2 or cracks or the like are easily generated in the face plate 1 near the T-shaped intersection 3. Therefore, conventionally, when setting the dimensions of the above-mentioned extrusion die material, a shape capable of bending is selected according to the know-how of the processing manufacturer, or extruded die materials having a plurality of dimensions and shapes are prepared in advance and actually used. The shape is set by performing a bending test, and there is a problem that it takes a lot of time to set the shape and the conditions such as bending.

Therefore, the present inventors have found that when bending an extruded mold material using a core, the extruded mold material is excellent in bending workability for suppressing the generation of wrinkles in ribs and eliminating cracks in the face plate. As a result of intensive studies on the shape, it was found that the size and shape of the T-shaped intersection between the face plate and the rib of the extruded mold material had an important influence on the occurrence of the wrinkles and cracks.

If at least the thickness t _{1 of the} face plate and the thickness t _{2 of the} rib at the intersection of the T-shape are t ₁ / t ₂ ≧ 1.1 (1), The present inventors have obtained the knowledge that the maximum stress generated at the T-shaped crossing portion can be reduced and the generation of wrinkles, cracks and the like can be suppressed.

Further, in addition to the above equation (1), the thickness t ₁ of the face plate and the corner radius R at the T-shaped intersection of the face plate and the rib are 0.5t ₁ ≤ It was found that when R ≤ 4t ₁ (2), cracks are less likely to occur in the vicinity of the T-shaped intersection of the face plate than in the case where the plate thickness is simply made to satisfy the relationship of the above formula (1).

[0008]

The present invention has been made on the basis of such findings, and the extruded mold material according to claim 1 has a tubular face plate and at least one connecting face plate. At least an extruded mold member formed by extrusion-molding the reinforcing ribs, the bending portion being formed in a direction in which one of T-shaped intersections of the face plate and the rib receives a tensile load and the other receives a compressive load The thickness t ₁ of the face plate and the thickness t _{2 of the} rib at the T-shaped intersection are set to be t ₁ / t ₂ ≧ 1.1.

The extruded profile according to claim 2 has a thickness t _{1 of the} face plate of the extruded profile according to claim ₁ and a corner radius at a T-shaped intersection between the face plate and the rib. R and 0.5t ₁ ≦ R ≦ 4t ₁ .

Further, the extrusion mold material according to claim 3 is characterized in that the one according to claim 1 or 2 is made of aluminum or an aluminum alloy.

[0011]

According to the extruded die material according to the first aspect, the maximum stress at the T-shaped crossing portion is reduced, and bending workability is improved. This will be described with reference to FIG. 2. FIG. 2 shows the maximum stress generated at the T-shaped crossing portion when the thickness t ₁ of the face plate and the thickness t _{2 of the} rib are changed. . In FIG. 2, the maximum stress is small when t ₁ / t ₂ is 1.1 or more, and the maximum stress rapidly increases when t ₁ / t ₂ is less than 1.1.

Therefore, by setting the above-mentioned t ₁ / t ₂ to be 1.1 or more, the ribs are stretched against the high strength of the face plate during bending, so that wrinkles of the ribs are reduced and cracks of the face plate are also reduced. . As a result, the bending workability of the extrusion mold material is improved, and the generation of defective products can be suppressed.

Further, in the extruded die material according to the second aspect, the maximum stress at the T-shaped intersection is further reduced. That is, FIG. 3 shows the maximum stress value when the value of the corner radius R is changed under the condition of the above formula (1). From the figure, the corner radius R is relative to the face plate thickness t _1. And the maximum stress value becomes smaller when it is within the above range. Therefore, by further setting the extruded mold material according to claim 1 as described in claim 2, cracks do not occur at the T-shaped crossing portion of the single-layer face plate.

Therefore, as described in claim 3, it is particularly suitable when the extruded mold material is formed of aluminum or an aluminum alloy.

[0015]

EXAMPLES The following experiments were conducted in order to confirm the effects of the extrusion mold material according to the present invention. First, as shown in FIG. 1, the dimension of the face plate is 100 mm in length × 75 mm in width ×
A plurality of date-shaped extruded aluminum-made materials having a length of 1300 mm, in which the thickness t ₁ of the face plate 11 and the thickness t ₂ of the rib 12 were changed, were prepared. Then, a core was put in the hollow portion of each of these extruded mold materials, and a bending test was conducted by a pressing machine at an angle of 30 degrees. Table 1 shows the results of the bending test for the extruded die members having the thickness t ₁ of the face plate 11 and the thickness t ₂ of the rib 12 shown in the table.

[0016] The circles indicate good bending workability. The shape of Δ indicates a bad shape after bending. The mark x shows a crack.

From Table 1, by setting the above-mentioned t ₁ / t ₂ to be 1.1 or more, the ribs 12 stretch against the high strength of the face plate 11 during bending, so that the wrinkles of the ribs 12 are reduced,
It can be seen that the number of cracks in the face plate is also reduced, and as a result, the bending workability of the extrusion die material is improved.

Next, using the same extruded aluminum material, the thickness t ₂ of the rib 12 is set to 1.8 mm, and the thickness t _{1 of the} face plate 11 and the corner R of the T-shaped intersection 13 are changed. I prepared several things. Then, the same bending test was performed on these extruded mold materials. Table 2
Shows the results of the above test.

From Table 2, the corner radius R is the face plate thickness t ₁
On the other hand, in the range of 0.5t ₁ ≤ R ≤ 4t ₁ , the maximum stress value becomes smaller, and as a result, the T-shaped intersecting portion 13 of the face plate 11 may not crack further. I understand.

[0020] Rib thickness t ₂ = 1.8 ◎ indicates good bending workability. The mark x shows a crack.

[0021]

As described above, according to the extruded mold material of the present invention, the tubular face plate and at least one reinforcing rib for connecting the face plates are integrally extruded, in particular, of aluminum or aluminum alloy. Even when the extruded shape member is molded and is bent in a direction in which one of the T-shaped intersections of the face plate and the rib receives a tensile load and the other receives a compressive load, a bending process is also performed. Therefore, wrinkles are easily formed on the ribs at the T-shaped intersections or cracks are generated on the face plate near the intersections without the trouble of setting the shape by a large number of experiments. It is possible to obtain an extruded mold material that does not swell.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment of an extrusion mold material of the present invention.

FIG. 2 is a graph for explaining the function and effect of the present invention.

FIG. 3 is a graph for explaining the function and effect of the present invention.

FIG. 4 is a side sectional view showing the shape of a conventional extruded mold material.

FIG. 5 is a side sectional view showing the shape of another conventional extruded mold material.

[Explanation of symbols]

 11 face plate 12 rib 13 T-shaped intersection

Claims (3)

[Claims] 1. A tubular face plate and at least one reinforcing rib connecting the face plates are integrally extruded, and one of a T-shaped intersection of the face plate and the rib. In the extruded shape member that is bent in a direction in which a tensile load is applied and the other is subjected to a compressive load, at least the thickness t _{1 of the} face plate and the thickness t _{2 of the} rib at the intersection of the T-shape are , T ₁ / t ₂ ≧ 1.1, an extruded mold material. 2. A thickness t ₁ of the face plate and a corner radius R at a T-shaped intersection of the face plate and the rib are set to 0.5t ₁ ≤ R ≤ 4t _1. The extrusion mold material according to claim 1. 3. The extruded mold material according to claim 1, wherein the face plate and the rib are integrally extruded from aluminum or an aluminum alloy.