JPH1148779A - Door beam material made of aluminum - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve buckling displacement and an energy absorption amount without increasing weight by devising a sectional shape, in a door beam material made of aluminum in a section consisting of outer and inner flanges and a web to intercouple them together. SOLUTION: A sectional shape is set in a manner to satisfy one or two or more conditions of under-mentioned four conditions of (1) the corner R (RFO) on the outer side of the tip of the extension part of an outer flange FO is 2.5 mm or less; (2) an outside corner R (RWO) in a spot where a web W and two flanges are intercoupled is 2-4 mm; (3) an outside corner R (RWO) in a spot where the web W and two flanges are intercoupled is 1.5-2 times a web width (tw); and (4) the length (LF) of the outer flange FO of the extension part of the outer flange FO is 1-2 times the length of the outside corner R (RWO) in a spot where the web and the flange are intercoupled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum door beam material used as a door reinforcing member for automobiles such as passenger cars and trucks.

[0002]

2. Description of the Related Art A door beam of a passenger car is attached to the inside of the door in a front-rear direction to absorb an impact at the time of a side collision, and is sometimes called an impact beam, an impact bar, a guard bar, a side beam, or simply a reinforcing member. This door beam is required to have a load absorbing performance at the time of collision. For example, in FMVSS (U.S. Federal Safety Standard), when a load is finally applied from the side of an actual vehicle, a bending load value for the load and a load-deformation amount Although a fixed reference value is provided for the energy absorption amount represented by the area of the relationship, these are generally assumed at the laboratory level to assume a collision with a vehicle, and as shown in FIG. Is evaluated by the bending performance of three-point bending in which both ends are supported and the center is pressed by a load jig.

FIG. 2 (b) is a schematic diagram of a load (P) -displacement (δ) curve obtained by the bending test of FIG. 2 (a). It shows that the load decreases due to buckling deformation due to the inability to withstand the load. Generally, in this load (P) -displacement (δ) curve, the maximum load is large and the displacement until buckling is large (see FIG. 3), energy absorption (area)
It is said that the larger is desirable.

[0004] Conventional door beams are typically 150k
gf / mm²Class high-tensile steel is used,
Considering the use of extruded aluminum bars from the perspective of weight reduction
Swelled. For example, Japanese Patent Application Laid-Open No. 5-31309 discloses
Is from Al-Zn-Mg-Cu based aluminum alloy extruded material
And Japanese Patent Laid-Open No. 7-1648.
No. 80 discloses the outer and inner flanges and
Aluminum with a cross-section consisting of a pair of webs connecting
For door beam materials made of rubber, the width of the upper flange is R ₁,under
Set the flange width to R₂, And the distance between the webs is W
Come, R₁<R₂, 0.4 × R₁≦ W ≦ 0.5 × R₁Noseki
It states that when satisfying the requirements, excellent characteristics can be secured
Have been.

[0005]

DISCLOSURE OF THE INVENTION The present inventors have developed an aluminum door beam material having a cross section composed of an outer and an inner flange and a web connecting the outer and inner flanges, without increasing the weight and without increasing the maximum load until the buckling occurs. In order to obtain a door beam material with large displacement (buckling displacement) and large energy absorption, various cross-sectional shapes of extruded aluminum members were studied. As a result, the outer corner R of the tip of the overhang of the outer flange is formed.
(R _FO ), the size of the outer corner R (R _WO ) at the point where the web and both flanges are connected are determined by the magnitude of the buckling displacement and the energy absorption in the load (P) -displacement (δ) curve of the door beam material. Was found to have a significant effect on
The present invention is characterized in that the optimum value is obtained based on this finding.

[0006]

First, an aluminum door beam member according to the present invention (claim 1) is an extruded member having an outer and an inner flange and a web connecting the outer and inner flanges. The outer corner R (R _FO ) at the tip is 2.5 mm or less. An aluminum door beam material according to the present invention (claim 2) is an extruded shape having an outer and inner flanges and a web connecting the outer and inner flanges, and an outer corner R (R) at a location where the web and both flanges are connected. _WO 2) is 2 to 4 mm. Alternatively, the outer corner R (R _WO ) is the web width (t _W )
It has a size 1.5 to 2 times as large as (claim 3). Further, an aluminum door beam material according to the present invention (claim 4) is an extruded shape material having an outer and inner flanges and a web connecting the outer and inner flanges, and the length (L _F ) of the overhang portion of the outer flange is web. And outer corner R where the two flanges are connected to each other (R _WO )
1 to 2 times as long as In the present invention, “made of aluminum” means made of aluminum or an aluminum alloy.

Needless to say, a door beam material having any two or all of the above characteristics is more desirable. Also, the outer flange _{F O,} the inner flange _{F I,} the web W, the outer side corner of the flange overhanging tip R _{(R FO),} the outer corner R _{(R WO)} of a portion web and the flange is connected, web width _{(t W} ), The length (L _F ) of the overhang portion of the outer flange and the like are as shown in FIG.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION An aluminum door beam material according to the present invention is provided with an inner flange facing the occupant when installed inside a door, an outer flange facing the outside of the vehicle and receiving a load from an impact from a vertical direction, and It is essential to have one or more webs connecting the flanges. In addition, since the maximum load is significantly improved by providing the overhang portions on the outer flange and the inner flange, the overhang portions are provided on both flanges in the present invention. The inner flange and the outer flange are preferably installed in parallel with each other, and another flange may be provided between the two. For example, a shape (a so-called semi-hollow shape) in which there is a gap in the middle of the inner flange when viewed in cross section is also included in the present invention.

[0009] In an aluminum door beam material according to the present invention, the outer flange _{F O} overhanging tip of the outer side corner R a _{(R FO)} was 2.5mm or less. This is because the conventional door beam material is rounded at the tip of the flange overhang as shown in FIG. 4 in consideration of extrudability,
This is because it has been found that the horn is more easily buckled and the buckling displacement and the amount of energy absorption are improved. When R _FO is larger than 2.5 mm, there is no such improvement effect. R _FO has a high effect of improving the smaller the buckling position and the energy absorption amount, preferably at 2mm or less, and more preferably 1mm or less. In addition, when extrudability is considered, 0.5 mm or more is preferable. here,
The fact that the outer corner at the tip of the overhanging portion of the outer flange is angular is less likely to buckle because the average thickness of the overhang is substantially larger than when it is rounded. The width-to-thickness ratio becomes smaller, and the area of the outer flange receiving the load becomes larger. (If it is rounded, the rounded portion does not contact the collision object or jig, and the contact area becomes smaller. ), It is presumed that the load may be received more dispersedly. For the outer flange _{F O} overhanging tip of the inner side corner R _{(R FI)} does not affect the more outer side corner R _{(R FO),} also need not be both identical, the outer side corner R _{(R FO} ) Similarly, preferably 2.5 mm or less, more preferably 2 mm or less,
mm or less. In the present invention, the buckling displacement until buckling is determined by the displacement (δ) when the load value becomes half of the maximum load (p) in the displacement region after the maximum load deformation, as shown in FIG. Defined.

[0010] On the other hand, the corner R of the projecting tip of the inner flange F _I, may be determined as appropriate according to the design concept of the door beam. For example, when using a protruding portion of the inner flange F _I for attachment to a vehicle door, if you need a flat surface, the corner R is better small, emphasizing the extrudability and surface properties conversely In this case, the larger the corner R, the better.

Further, in the aluminum door beam material of the present invention, the outer corner R (R _WO ) where the web and the flanges are connected is 2 to 4 mm. In the conventional door beam material, the corner R is considered only from the viewpoint of the extrudability, but the present inventors have proposed the corner R
It was found that the magnitude of (R _WO ) greatly affected the buckling displacement, and the buckling displacement could be greatly improved by setting this value in the range of 2 to 4 mm. The outer corner R (R _WO) can not be improved buckling position and the energy absorption effect is weak door beam material if less than 2mm to prevent buckling of the projecting portion of the outer flange F _O. This is the outer corner R
When setting the (R _WO) than 2mm, and since R _WO is has the effect of supporting the overhang portion when a load is applied to the projecting portion of the outer flange F _O, no practically its effect is 2mm or less Guessed. Also, conversely, 4mm
If it exceeds, the buckling prevention effect is not improved even though the weight increases. On the other hand, the inner corner R (R _WI ) is not particularly limited, but is preferably 2 to 4 mm.

Further, in an aluminum door beam material according to the present invention, the outer corner R a _{(R WO)} was 1.5 to 2 times larger than the web width _{(t W),} the _{R WO} is web width (t _W ) when it has a width of 1.5 to 2 times, that is,
This is because when R _W = (1.5 to 2) × t _W , the effect of improving the buckling displacement and the energy absorption increases. However, R _WO can not be improved buckling position and the energy absorption effect is weak door beam material to prevent buckling of the overhanging portion of the outer flange F _O when not less than 1.5 times the t _W Conversely, if it exceeds twice, the buckling prevention effect is saturated and the weight increases. On the other hand, inside corner R
Although (R _WI ) is not particularly limited, it is still preferably (1.5 to 2) × t _W mm.

Furthermore, the aluminum door beam material according to the present invention, associated with the length of the projecting portion of the outer flange _{F O (L F)} the outer corners of the portion where the web and the flange are linked _{R (R WO), L F} = (1-2) × R _W
And L _F and R _WO is buckled position and energy absorption amount by setting the cross-sectional shape so as to satisfy the above relationship is greatly improved. Here, the L _F was more R _WO is, L _F can not be improved short and buckling prevention effect is small buckling position of the web than this, 2 × weight to that as R _W or less This is because the buckling prevention effect is not improved for the increase. The length of the inner flange F _I (overhang portion of the inner flange length) for which the length of the outer flange F _O (the extending portion of the outer flange F _O length) neutral axis longer than If it is biased toward the inner side, there is an advantage that cracking (breaking) on the inner side is delayed when a load at the time of collision is received, and the amount of energy absorption increases.

As described above, in designing the sectional shape of the aluminum door beam material, the following items should be considered.
Requirements were listed individually. R _FO is 2.5mm or less, _{R WO} is 2-4 mm, 1.5 to 2 times the _{R WO} is _{t W, L F} is 1 to 2 times buckling position and energy by combining these requirements _{R WO} The effect of improving the absorption amount is even higher, and specifically,
+, + (And / or), +, (and / or)
A door beam material having two to four requirements such as +, + (and / or) +, and the like is preferable. Note that the aluminum door beam material of the present invention does not need to be symmetrical in a cross section perpendicular to the length direction. For example, the length (L _F ) of the left and right overhanging portions of the outer flange, the outer corners at the tips of both overhanging portions. R (R _FO ), the width (t _W ) of each web, etc. when having a plurality of webs may be different from each other. Also, the outer corners R (R _WO ) where the web and the flange are connected need not all be the same.

Various aluminum or aluminum alloys can be used as the aluminum door beam material according to the present invention. In particular, from the viewpoint of the strength of the door beam material, Mg: 0.8 to 1.5%, Zn: 4 7000 series alloys containing up to 7% are preferred. For example, Mg: 0.8
~ 1.5%, Zn: 4 ~ 7%, Ti: 0.005 ~ 0.
3%, Cu: 0.05-0.6%, M
n: 0.2-0.7%, Cr: 0.05-0.3%, Z
r: An aluminum alloy containing one or two or more selected from 0.05 to 0.25% and consisting of Al and the remaining unavoidable impurities can be mentioned as a preferable example. The reason for adding each element in the 7000 series alloy is as follows.

Mg, Zn Mg and Zn are elements necessary for maintaining the strength of the aluminum alloy. Mg is less than 0.8%, Zn is 4%
If it is less than the desired strength, the desired strength cannot be obtained. Also, when Mg is 1.5
% And Zn exceeding 7%, the extrudability of the aluminum alloy is reduced and the elongation is also reduced, so that desired characteristic values cannot be obtained. Therefore, Mg: 0.8-1.5%, Zn: 4
To 7%. Ti Ti is an essential element for refining the ingot structure. T
When i is less than 0.005%, the effect of miniaturization is not sufficient, and when i is more than 0.3%, the compound is saturated and a giant compound is generated. Therefore, the content of Ti is 0.005% to 0.1%.
3%.

Cu, Mn, Cr, Zr These elements increase the strength of the aluminum alloy. Further, Cu improves the stress corrosion cracking resistance of the aluminum alloy, and Mn, Cr, and Zr have a function of forming a fibrous structure in the extruded material to strengthen the alloy.
Seeds or more are added as appropriate. The preferred range is Cu: 0.0
5 to 0.6%, Mn: 0.2 to 0.7%, Cr: 0.0
5 to 0.3%, Zr: 0.05 to 0.25%. If each is less than the lower limit, the above action is insufficient, and
Exceeding the upper limit will result in poor extrudability and Cu will result in poor general corrosion resistance. Inevitable impurities Among the inevitable impurities, F
e is an impurity most contained in the aluminum base metal, and if present in the alloy exceeding 0.35%, coarse intermetallic compounds are crystallized at the time of casting, which impairs the mechanical properties of the alloy. Therefore, the content of Fe is restricted to 0.35% or less. Further, when casting an aluminum alloy, impurities are mixed from various routes such as a base metal and an intermediate alloy of an additive element.
There are various elements to be mixed, but impurities other than Fe alone have 0.05% or less, and if the total amount is 0.15% or less, it hardly affects the properties of the alloy. Therefore, elements contained as impurities other than Fe alone are 0.05% or less,
It is desirable to limit the total amount to 0.15% or less.

[0018]

【Example】

(Embodiment 1) As shown in FIGS. 6A and 6B, the outer and inner flanges are mutually parallel and are
Mg consisting of two webs and having a symmetrical cross-sectional shape:
1.4%, Zn: 6.5%, Cu: 0.2%, Zr:
An extruded Al-Mg-Zn-based aluminum alloy material containing 0.15%
Pushed in 50mm. FIG. 7 shows a load (P) -displacement (δ) curve at that time. Table 1 shows the maximum load, buckling displacement, and energy absorption obtained from FIG. 7 together with the unit weight of each member. The door beam material A is
Outer flange length is 38mm, width is 4.4mm,
Length of inner flange is 48mm, width is 4.6mm,
The length of the web is 28 mm and the width is 2.1 mm. The difference in the cross-sectional shape of the door beam materials A and B is the length (L _F ) of the overhang of the outer flange and the outer corner at the tip of the overhang of the outer flange. R (R _FO ) only.

[0019]

[Table 1]

As shown in Table 1, the outer flange F _O
In comparison with Comparative Example A, in which the outer corner R (R _FO ) at the tip of the overhanging portion is within the range defined in the present invention, and Comparative Example A out of the range of the present invention, the unit weight is the same or less for the same material. Nevertheless, the maximum load is the same, the buckling displacement is improved by 17%, and the energy absorption is improved by 10%. Note that the same relationship is defined by 7N01 defined in JIS,
Alloys of 6000 series and 7000 series such as 6061, 6063, 6N01 alloy, 6082 which are internationally registered alloys, etc. were also established.

(Embodiment 2) As shown in FIGS. 8C to 8E, the outer and inner flanges are parallel to each other and two webs vertically connecting the outer and inner flanges and have a symmetrical cross-sectional shape. An Al-Mg-Zn-based aluminum alloy extruded shape was pressed in by 300 mm in a three-point bending test with a span of 950 mm. 8C to 8E can be summarized as shown in Table 2. Also, among the cross-sectional shapes of the door beam materials C to E, the width and thickness of the outer flange and the inner flange, the overall height,
The distance between the two webs is the same. Load at that time (P)
FIG. 9 shows the displacement (δ) curve. Table 3 shows the respective energy absorption amounts obtained from FIG. 9 together with the unit weight of the members.

[0022]

[Table 2]

[0023]

[Table 3]

As shown in Table 3, when a reference door beam material of Comparative Example C is not at all meet the shape requirements specified in the present invention, invention example R _W and L _{F /} R _W satisfies the requirements of the present invention D the energy absorption ratio to a weight ratio only 5% increase is increased by 29%, the invention example E, further R _{W /} t _W satisfies the provisions of the present invention, the weight ratio is increased by 9% However, the energy absorption ratio shows a remarkable improvement of 73%. Note that the same relationship is defined by 7N0 specified in JIS.
1,6061, 6063, 6N01 alloy, 6000 series alloy such as 6082 which is an internationally registered alloy, and 7000 series alloy were also established.

[0025]

According to the present invention, the buckling displacement and the energy absorption can be improved without increasing the weight by devising the sectional shape of the aluminum door beam material. Weight can be reduced. Therefore, it is possible to contribute to the weight reduction of the door beam material and the improvement of the performance as the cushioning member.

[Brief description of the drawings]

FIG. 1 is a diagram showing a cross-sectional shape of a door beam material according to the present invention and symbols of respective parts.

2A and 2B are an explanatory view showing a three-point bending test method of a door beam material and a schematic view of a load (P) -displacement (δ) curve obtained by a three-point bending test.

FIG. 3 is a schematic diagram of a load (P) -displacement (δ) curve obtained by performing a three-point bending test on a door beam material.

FIG. 4 is a diagram showing a cross-sectional shape of a conventional aluminum door beam material.

FIG. 5 is a diagram illustrating buckling displacement of a door beam material.

FIG. 6 is a diagram showing a cross-sectional shape of door beam members A and B used in Example 1.

FIG. 7 is a load (P) -displacement (δ) curve obtained by performing a three-point bending test on door beam materials A and B.

FIG. 8 is a diagram showing the cross-sectional shapes of door beam materials C to E used in Example 2.

FIG. 9 is a load (P) -displacement (δ) curve obtained by performing a three-point bending test on door beam materials CE.

[Explanation of symbols]

F _O outer flange F _I inner flange W web R _FO size t _W web width L _F overhang of the outer flange of the outer corner R places the outer flange projecting tip outer side corner R _{R WO} web and flanges of the coupling Part length

Claims (5)

[Claims] 1. An extruded aluminum member having an outer flange, an inner flange and a web connecting the outer flange and an inner flange, wherein an outer-side corner R (R _FO ) at a tip of a protruding portion of the outer flange has a cross section perpendicular to the longitudinal direction. An aluminum door beam material having a diameter of 0.5 mm or less. 2. An extruded aluminum material having an outer and an inner flange and a web connecting the outer flange and the inner flange, wherein an outer corner R (R _WO ) at a point where the web and the two flanges are connected in a cross section perpendicular to the longitudinal direction. 2-4m
m, an aluminum door beam material. 3. An extruded aluminum material having an outer and inner flanges and a web connecting the outer and inner flanges, wherein an outer corner R (R _WO ) at a location where the web and the two flanges are connected in a cross section perpendicular to the longitudinal direction. aluminum door beam material characterized by having a 1.5 to 2 times the size of the web width (t _W). 4. An extruded aluminum material having an outer and inner flange and a web connecting the outer and inner flanges, wherein the length (L _F ) of the overhang portion of the outer flange in a cross section perpendicular to the longitudinal direction is equal to the web and the two flanges. Characterized in that the length is 1 to 2 times as long as the outer corner R (R _WO ) of the place where the door beam is connected. 5. An extruded aluminum material having a Mg content of 0.8:
The aluminum door beam material according to any one of claims 1 to 4, wherein the aluminum door beam material is made of an aluminum alloy containing 1 to 1.5% (wt%, the same applies hereinafter) and Zn: 4 to 7%.