JP4773853B2 - Aluminum alloy extrusions for automotive door beams - Google Patents

Description

  The present invention relates to an aluminum alloy extruded shape for an automobile door beam used as a door beam for absorbing an impact at the time of collision with an automobile door.

  In recent years, as an energy absorbing member (door beam) that absorbs energy at the time of a collision with an automobile door, an aluminum alloy extruded shape has been tried to meet the demand for weight reduction. A combination of the above alloy composition and structure has been proposed (see Patent Document 1).

The above proposal uses an Al-Mg-Si alloy or Al-Zn-Mg alloy with a specific composition, and the shape of the extruded shape is II (Roman numeral 2). However, in this case, the effective space in the vertical direction of the automobile door to which the door beam is mounted is wide, and when the width of the door beam is increased or the side outside the side door is rounded and the impact load is applied. Appropriate when the door surface (hereinafter, the side door surface where the impact load on the outside of the side door is applied is the compression side flange and the inner surface of the side door opposite to the side door surface where the impact load is applied) is not flat. A door beam cannot be obtained, and therefore impact energy absorption as a door beam is not always sufficient.
JP-A-5-247575

  In order to obtain a further improved aluminum alloy extruded shape for an automobile door beam, the inventors absorbed impact energy in the aluminum alloy extruded shape for an automobile door beam, the composition of the aluminum alloy, the shape and dimensions of the extruded shape, and the like. Various tests and studies were conducted on the relationship. The present invention has been made as a result, and its purpose is to have a high energy absorption capability, and to effectively protect the passenger by absorbing the energy generated by the impact at the time of collision with the door of the automobile. It is an object of the present invention to provide an aluminum alloy extruded shape for an automobile door beam.

In order to achieve the above object, an aluminum alloy extruded shape for an automobile door beam according to claim 1 is an aluminum alloy extruded shape used as a shock absorbing door beam at the time of a collision with an automobile door. In the cross section of the material, a first side formed in an asymmetrical chevron composed of a long side part and a short side part and a second side formed in a straight line are provided facing each other, and the first side and the second side are provided. An inner column connecting the long side portion of the first side and the second side in the hollow shape member formed by connecting both ends of the side by a third side and a fourth side. The hollow pillar is divided into two, and the inner pillar is inclined toward the long side so as to move away from the short side of the first side with respect to the second side at an angle of θ. is formed, the third side and the fourth side is made vertical portion extending perpendicularly from said second side, said extruded profile , Zn: 4.0 to 9.0% (mass%, hereinafter the same), Mg: 1.0~1.5%, Cu : 0.01~0.5%, V: 0.01~0.15 % And Ti: 0.005 to 0.30%, Mn: 0.05 to 0.2%, Cr: 0.01 to 0.5% and Zr: 0.05 to 0.3% It is characterized by being composed of an aluminum alloy containing one or more of them and the balance Al and impurities.

According to a second aspect of the present invention , there is provided an aluminum alloy extruded profile for an automobile door beam according to the first aspect , wherein the third side and the fourth side are continuous with a vertical portion extending perpendicularly from the second side. And an inclined portion extending inward and connected to the long side portion and the short side portion of the first side .

The aluminum alloy extruded shape for automobile door beam according to claim 3 is characterized in that, in claim 1 or 2 , an angle θ with respect to the second side of the inner pillar is 70 ° or more .

An aluminum alloy extruded shape for an automobile door beam according to claim 4 is any one of claims 1 to 3 , wherein the tensile strength (σ _B ) is 400 to 600 MPa, the proof stress (σ _0.2 ) is 350 to 570 MPa, and the elongation ( δ) is 5 to 20%.

  ADVANTAGE OF THE INVENTION According to the present invention, an aluminum alloy extruded shape for an automobile door beam that has a high energy absorption capability and can effectively absorb the energy generated by the impact at the time of a collision with an automobile door to protect the passenger. Is provided.

  An aluminum alloy extruded shape for an automobile door beam according to the present invention comprises a tempered heat-treated Al-Zn-Mg alloy hollow extruded shape having a specific composition, and subjected to T5 treatment or T6 treatment as a tempering after extrusion. It is preferable to apply.

  Explaining the significance and reasons for limitation of the components of the aluminum alloy constituting the extruded profile of the present invention, Zn and Mg are components necessary for maintaining sufficient strength when the extruded profile is applied to a door beam. . The preferred contents are Zn: 4.0 to 9.0% and Mg: 1.0 to 1.5%, respectively. If the content is less than the lower limit, it is difficult to obtain sufficient strength, and the content exceeds the upper limit. Then, extrudability and elongation are lowered. When the elongation decreases, cracks occur during bending deformation, deteriorating energy absorption characteristics.

  Cu functions to increase strength. The preferred content is in the range of 0.01 to 0.5%, and if it is less than 0.01%, sufficient strength is difficult to obtain, and if it exceeds 0.5%, the extrudability and corrosion resistance are lowered. Mn, Cr, and Zr function to increase the strength of the extruded structure as a fiber. The preferred contents are Mn: 0.05 to 0.2%, Cr: 0.01 to 0.5%, and Zr: 0.05 to 0.3%, respectively. Occasionally huge compounds are formed, reducing toughness.

V is an important component for improving toughness. The preferred content is in the range of 0.01 to 0.15%, and if it is less than 0.01%, the effect is not sufficient, and if it exceeds 0.15%, a huge compound is produced during casting and the toughness is reduced. Let Ti is an element that refines the cast structure to improve the strength. The preferable content is in the range of 0.005 to 0.30%. If the content is less than 0.005%, the effect is small, and if it exceeds 0.30%, a large amount of compound is produced during casting to lower toughness.

  As shown in FIG. 1, the aluminum alloy extruded shape for an automobile door beam according to the present invention has a first side 2 formed in an asymmetric chevron comprising a long side portion 2 </ b> A and a short side portion 2 </ b> B in a cross section, and a linear shape. The second side 3 formed on the second side 3 is opposed to each other, and both ends of the first side 2 and the second side 3 are connected to the third side 4 (outer column) and the fourth side 5 (outer column). The inner pillar 6 that connects the long side portion 2A of the first side 2 and the second side 3 is provided inside the hollow cross-sectional shape formed by connecting the hollow cross-sectional shape with the two hollow portions. It is divided into H1 and H2. In the case of application as a door beam, the first side 2 formed in a mountain shape is the outer side, that is, the compression side flange to which an impact force is applied, and the second side 3 positioned on the inner side is the tension side flange.

The aluminum alloy extruded profile of the present invention is also suitable when the width of the door beam is large, for example, when the length Wt of the second side 3 is 50 to 75 mm. When the number of webs is two as in the previously proposed type II (square pipe-shaped hollow cross-section, without the inner pillar as in the present invention), a flange (formed in a chevron shape) during bending deformation Since the amount of cross-sectional deformation of the first side 2 and the second side 3) is increased, the energy absorption amount is reduced.

On the other hand, as in the present invention, the inner pillar 6 is provided with a hollow pipe shape having an irregular square pipe shape, that is, the compression side flange (first side 2) and the tension side flange (second side). What is formed by connecting the side 3) with three webs (columns) (outer column (third side 4, fourth side 5) and inner column 6) is excellent in that early cross-sectional deformation is prevented. Energy absorption characteristics can be obtained. When the first side 2 is formed in a symmetric shape, the inner column 6 is buckled in the initial stage of bending deformation, and the load is likely to decrease. By forming the first side chevron asymmetrically and tilting the inner column 6 toward the long side so as to be away from the short side of the first side with respect to the second side, bending deformation is large. As the inner pillar gradually falls, the cross section is deformed so that the inner column gradually falls, and a sudden load drop can be prevented.

In the aluminum alloy extruded profile 1 of the present invention formed as described above, as shown in FIG. 1, the inner column 6 extends from the short side 2 </ b > B of the first side 2 with respect to the second side 3. It is desirable that the long side portion 2A is inclined at an angle of θ so as to be far away. When a force is applied from the first side 2 side (compression side) due to the form of the inner pillar 6 and the presence of the hollow section divided into two by the inner pillar 6, the inner pillar 6 is deformed without breaking. Energy can be absorbed effectively.

In this case, the angle θ is preferably 70 ° or more . If it is less than 70 °, the inner column tends to collapse at the initial stage of bending deformation, and the amount of energy absorption decreases. If θ exceeds 90 ° and is tilted toward the short side 2B side of the first side, the position of the inner column approaches the peak of the mountain shape, so that a large load is applied to the inner column at the beginning of bending deformation. It becomes easy to buckle and energy absorption is reduced.

Further, in the aluminum door profile for automobile door beam of the present invention, it is desirable that vertical portions 4A and 5A extending perpendicularly from the second side 3 are formed on the third side 4 and the fourth side 5. . As shown in FIG. 2, the third side 4 and the fourth side 5 are vertically extended from the second side 3 to the vertical portions 4A and 5A, and the vertical portions 4A and 5A are continuously extended to the inside. It is further desirable that inclined portions 4B and 5B connected to the long side portion 2A and the short side portion 2B of the first side 2 are formed so that Wc <Wt (see FIG. 3). It is possible to further increase the energy absorption capacity. Vertical portions 4A and 5A extending perpendicularly from the second side 3 are not formed on the third side 4 and the fourth side 5, and the third side 4 and the fourth side 5 are inclined and the second side 5 and the fourth side 5 are inclined. When the first side 2 and the second side 3 are connected, the amount of cross-sectional deformation becomes large at the initial stage of bending deformation, the third side 4 and the fourth side 5 buckle, and the amount of energy absorption is increased. descend.

The aluminum extruded profile of the present invention has the following required strength properties when applied as a door beam: Tensile strength (σ _B ): 400 to 600 MPa, Yield strength (σ _0.2 ): 350 to 570 MPa, Elongation (δ): It is preferable to have a tensile property of 5 to 20%.

With reference to FIG. 3, it will be as follows if the preferable dimensional relationship in each site | part of the aluminum alloy extruded shape for automobile door beams of this invention is described.
Wt = 50 to 75 mm, Wc / Wt = 0.85 to 0.95
H = 30-40 mm, H / H2 = 1.5-1.20, H / H3 = 1.10-1.40, H1 = 10-18 mm
Wc / Wc1 = 1.20-1.70, Wt1 / Wt2 = 1.10-1.40
5.5 ≧ Tc1 ≧ 3.0, 5.5 ≧ Tc2 ≧ 3.0
4.0 ≧ Tw1 ≧ 1.8, 4.0 ≧ Tw2 ≧ 1.8, 4.0 ≧ Tw3 ≧ 1.8
7.0 ≧ Tt1 ≧ 3.5, 7.0 ≧ Tt2 ≧ 3.5

  Examples of the present invention will be described below. In addition, this Example shows one embodiment of the present invention, and the present invention is not limited to this.

  Zn: 7.0%, Mg: 1.2%, Cu: 0.1%, V: 0.015%, Ti: 0.04%, Mn: 0.07%, Cr: 0.02%, Zr : The aluminum alloy which contains 0.15% and which consists of remainder Al and an impurity is ingoted, and the obtained billet is homogenized at 470 degreeC for 24 hours, Then, it is shown in FIGS. It was extruded into a hollow shape having a cross-sectional shape and dimensions shown in Table 1. Immediately after the extrusion, it was rapidly cooled to room temperature, subjected to natural aging treatment for 2 days, and further subjected to aging treatment at 120 ° C. for 24 hours, and then cut into a length of 1200 mm to obtain a test material. The strength of each test material is the same.

  As shown in FIG. 10, the obtained test material was FMVSS (Federal Motor Vehicle Safety Standard) No. 214: Bending deformation was evaluated by a three-point bending test based on Side Door Strength. The support span was 800 mm. In the evaluation of bending deformation, a relationship curve between load and displacement is obtained by a three-point bending test, and the area S is expressed as energy as shown in FIG. 11 (schematic diagram showing the relationship between the load value and the displacement amount in the bending test). Absorption amount. In this example, an area consisting of a curve up to a displacement of 300 mm and a horizontal axis (displacement axis) is defined as an energy absorption amount, and the maximum load per unit mass, that is, (maximum load) / (mass of test material), and unit. The energy absorption amount per mass, that is, (energy absorption amount) / (mass of test material) was evaluated, and the value of test material 1 was set to 1.00 for relative comparison. The results are shown in FIG. In FIG. 12, the test material 2 has almost the same curve as the test material 1, and thus the illustration is omitted.

  As can be seen in Table 2, the test materials 1 and 2 according to the present invention have a maximum load ratio per unit mass of 1.00 and 0.99, respectively, and an energy absorption amount ratio of 1.00 and 0.98, respectively. In both cases, energy was efficiently absorbed up to a displacement of 300 mm while gradually deforming the cross section.

On the other hand, the test material 3 that deviates from the requirements of the present invention has no inner pillar, and therefore the entire cross section is significantly deformed at the initial stage of bending deformation and the load is reduced. Therefore, the maximum load and the energy absorption amount are extremely small. It became low. The test material 4 absorbed energy up to a displacement of 300 mm while gradually deforming the cross section. However, since the compression side flange was flat, the plastic section coefficient per unit mass was small, and the maximum load and energy absorption amount were low.

The test material 5 absorbed energy up to a displacement of 300 mm while gradually deforming the cross section, but the degree of cross section deformation was significant and the energy absorption amount was low. The test material 6 had a low energy absorption because the load was reduced due to buckling of the inner column at the initial stage of bending deformation.

It is sectional drawing which shows the Example of the aluminum alloy extrusion shape material by this invention. It is sectional drawing which shows the other Example of the aluminum alloy extruded shape material by this invention. It is sectional drawing for demonstrating the dimensional relationship of each site | part of the aluminum alloy extrusion shape material by this invention. It is sectional drawing of the aluminum alloy extrusion shape member used in the Example. It is sectional drawing of the aluminum alloy extrusion shape member used in the Example. It is sectional drawing of the aluminum alloy extrusion shape member used in the Example. It is sectional drawing of the aluminum alloy extrusion shape member used in the Example. It is sectional drawing of the aluminum alloy extrusion shape member used in the Example. It is sectional drawing of the aluminum alloy extrusion shape member used in the Example. It is the schematic which shows the bending test method in an Example. It is a schematic diagram which shows the relationship between the load value and displacement amount in a bending test. In the bending test in an Example, it is a related figure with the value which showed the displacement amount of each test material, and the maximum load per unit mass as the test material 1 was set to 1.00.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Aluminum alloy extrusion shape material of this invention 2 1st edge | side (compression side flange)
2A Long side part 2B Short side part 3 2nd side (tensile side flange)
4 Third side (outer pillar)
4A Vertical portion 4B Inclined portion 5 Fourth side (outer column)
5A Vertical part 5B Inclined part 6 Inner pillar H1 Hollow part H2 Hollow part

Claims (4)

An aluminum alloy extruded profile used as a shock absorbing door beam at the time of a collision with an automobile door, wherein the extruded profile has a cross section of the extruded profile formed into an asymmetrical chevron composed of a long side and a short side. A hollow shape in which one side and a second side formed in a straight line are opposed to each other, and both ends of the first side and the second side are connected by a third side and a fourth side. An inner column that connects the long side portion of the first side and the second side is provided inside the material to divide the interior of the hollow shape material into two, and the inner column is The third side and the fourth side are perpendicular to the second side. The second side and the second side are formed at an angle of θ that is inclined toward the long side so as to be away from the short side of the first side. The extruded profile is Zn: 4.0-9.0% (mass%, the same applies hereinafter), Mg: 1.0-1.5%, Cu: 0.01- 0.5%, V: 0.01 to 0.15% and Ti: 0.005 to 0.30%, Mn: 0.05 to 0.2%, Cr: 0.01 to 0.5 % And Zr: 0.05 to 0.3% of one or more of aluminum alloy, aluminum alloy extruded form for automobile door beam characterized by being composed of an aluminum alloy composed of the balance Al and impurities Wood. The third side and the fourth side include a vertical part extending perpendicularly from the second side, and a continuous side of the vertical part and extending inwardly, and a long side part and a short side part of the first side. claim 1 automotive door beam for aluminum alloy extruded shape member, wherein the an inclined portion connecting the. 3. An aluminum alloy extruded shape for an automobile door beam according to claim 1, wherein an angle [theta] with respect to the second side of the inner pillar is 70 [deg.] Or more . Tensile strength (sigma _B) is 400～600MPa, yield strength (sigma _0.2) is 350～570MPa, elongation ([delta]) is according to any one of the preceding claims, characterized in that a 5-20% Aluminum extrusion for automotive door beams.

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