JP2000288643A - Method for press-forming embossed aluminum alloy sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To press an embossed sheet without squeezing unevenness of embosses by setting the clearance between die faces and the clearance between a die and a punch to be not less than the height of the unevenness given to the sheet by embossing an aluminum alloy sheet. SOLUTION: The clearance C1 between die faces and the clearance C2 between a die and a punch are preferably set to be 1.0 to 1.5 times the height of unevenness (the emboss height) given to a sheet by embossing an aluminum alloy sheet. The clearance C1 between a die 2 and a wrinkle holding plate 3 is adjusted by changing the thickness of a spacer 4 arranged between the die 2 and the wrinkle holding plate 3. The punch 1 and the die 2 are designed and arranged so as to ensure the clearance C2 therebetween. The thickness of the spacer 4 is set to be 1.0 to 1.5 times the emboss height, and the aluminum alloy sheet is pressed by setting the clearance C2 between the die 1 and the punch 2 to the thickness of the spacer 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for press-forming an embossed aluminum alloy plate (Al alloy plate). It is suitable for press forming an aluminum alloy plate.

[0002]

2. Description of the Related Art A shielding material is attached to an exhaust guide portion such as around a muffler of an automobile, a transmission portion, a periphery of an engine mount, or a heat generating portion of a home electric appliance for thermal isolation. This shielding material,
In general, it is called a heat insulator (heat protector), and as its characteristics, in addition to heat insulation, moldability, rigidity, heat dissipation, vibration resistance, light weight, and the like are required. Conventionally, hot-dip galvanized steel sheets have been the mainstream as such a shielding material, but aluminum or an alloy thereof has recently begun to be used from the viewpoint of weight reduction.

[0003]

For example, in the case of a shielding material for an automobile, since it is attached to a portion such as around the exhaust, the shielding material often has a very complicated portion or shape. Therefore, in the case of Al alloy flat plates that have been used as shielding materials, press forming is difficult, and there is a problem in practical use that wrinkles and cracks are likely to occur during press forming.
When wrinkles occur during press molding, when they are severe, the wrinkles become "overlapping wrinkles", which may cause cracks.

On the other hand, instead of this Al alloy flat plate, recently, an Al alloy plate provided with irregularities by embossing has attracted attention. The embossed Al alloy plate is more uneven than the flat plate of the same
Since the rigidity is improved, there is an advantage that the thickness can be reduced and the weight can be reduced.

[0005] However, even in the case of the Al alloy plate subjected to the embossing, there is a problem in press forming as in the case of the Al alloy plate. In particular, if the molding height is made relatively high, the embossing irregularities will be crushed. Then, the embossed Al alloy plate after the press forming cannot exhibit desired properties such as heat insulation and heat dissipation obtained as an effect of embossing. Therefore, in order to prevent such a situation, the press-forming height of the embossed Al alloy plate must be made relatively small, and the press-formed product must be restricted. For this reason, there is a demand for a press forming method in which the embossed Al alloy plate is less likely to crush unevenness of the embossing even if the press forming height is increased.

The problem in the press forming method of the embossed Al alloy plate is that the design of the die in the press forming method is based on the same conditions or the flat plate press forming method as the conventional flat plate press forming method. It is caused by what is done based on the data given. In this regard, the design of the die in the method for press-forming an embossed Al alloy plate needs to be determined separately from the press-forming conditions of the flat plate, as it is unique to the embossed Al alloy plate. . However, to date, there are no investigation examples relating to this, and in particular, regarding the clearance between die faces and the clearance between a die and a punch, which are important in the design of the mold, the appropriateness for an embossed Al alloy plate The fact is that the design has not been made.

Accordingly, an object of the present invention is to provide a method for press-forming an embossed aluminum alloy sheet so that unevenness of the embossing is not crushed even when press-forming so that the forming height is relatively high. That is.

[0008]

In order to achieve the above object, the present inventor has determined whether or not embossing irregularities are crushed during press forming of an Al alloy plate by determining whether the die faces (die and wrinkle pressing plate) are crushed. Under the assumption that it would depend on the clearance and the clearance between the die and the punch, the values of these clearances were varied to determine the limit forming height at which the embossing irregularities were crushed. As a result, as will be apparent from the examples described later, the clearance between the die faces and the clearance between the die and the punch are adjusted to the height of the irregularities imparted to the aluminum alloy plate by embossing (hereinafter, referred to as “emboss height”). "), It was found that the intended purpose could be achieved (claim 1).

In other words, according to the above-mentioned method, even if the forming height is made larger than before, it is possible to prevent the unevenness due to the embossing from being greatly damaged. The degree of freedom can be increased. As described above, according to the present invention, it has been found that it is important to provide an appropriate clearance at the time of press forming in forming an embossed aluminum alloy sheet.

The reason that the clearance between the die faces and the clearance between the die and the punch are the same is that if the clearance between the die faces is larger, the inflow of the material increases and wrinkles easily occur. This is because, if the clearance with the punch is larger, the inflow of the material is reduced and cracks are more likely to occur.

Further, as will be apparent from the examples described later, from the viewpoint of further increasing the forming limit height, the clearance between the die faces and the clearance between the die and the punch are adjusted to the emboss height of the aluminum alloy plate. It is preferably in the range of 1.0 to 1.5 times (claim 2). This is because if it is less than 1.0, unevenness of the emboss will be crushed, and if it exceeds 1.5, overlapping wrinkles will occur and cause cracks.

In the present invention, the embossing applied to the aluminum alloy plate preferably forms regular irregularities on the aluminum alloy plate. As described below, the “regular unevenness” may be provided as a planar or two-dimensional pattern in which an unevenness pattern is repeated along two intersecting directions, or may be provided in one direction. The uneven pattern is repeated along, but may be provided as a one-dimensional pattern having no unevenness in a direction orthogonal to this.

That is, the shape of the embossing here is, for example, as shown in FIGS. 1 (a) and 1 (b). In FIG. 1A, a white circle (○) represents a convex vertex by embossing, a black circle (●) represents a concave vertex by embossing, and a solid line is a ridge line connecting the convex vertices. is there. FIG. 1B is a cross-sectional view passing through two convex portions A and A ′ and one concave portion B in FIG.

As described above, an example of the embossed aluminum alloy plate according to the present invention has regular convex portions in a lattice shape, and is shifted in the longitudinal and lateral directions of the lattice by a certain distance. This is an embossed plate provided with concave portions regularly in a shape. As is apparent from FIG. 1B, the emboss height h is the distance from the highest position to the lowest position in the vertical direction of the plate surface (that is, the highest point of the unevenness formed by embossing). From the point to the lowest point). In addition, the distance between protrusions (hereinafter, referred to as “emboss pitch”) 1 is a distance along the horizontal direction between adjacent protrusions, as shown in FIG.

Another example of the embossed aluminum alloy plate according to the present invention is an embossed plate having convex portions regularly in one direction as shown in FIG. In this case as well, the emboss height h is defined by the distance from the highest position to the lowest position in the vertical direction of the plate surface, as described with reference to FIGS. 1 (a) and 1 (b). Is defined as the distance along the horizontal direction between adjacent convex portions.

The aluminum alloy sheet used in the press forming method of the present invention may be made of AA or JIS standard 1000 series, 3000 series, 5000 series, depending on the required characteristics.
Or 6000 series aluminum alloy is appropriately selected and used. For example, as in the embodiment described below, 1
A 1050 aluminum alloy, which is one of the 000 series aluminum alloys, may be used.

[0017]

Next, a preferred embodiment of the present invention will be described with reference to the drawings.

FIG. 3 is a schematic diagram showing a main part of a press forming apparatus used in the method of press forming an embossed aluminum alloy plate according to the present embodiment. In FIG. 3, a die 2 having an opening of a predetermined shape such as a circle or a rectangle is paired with a punch 1 movable along a normal direction of the opening, and press-formed on an aluminum alloy plate (not shown). It is configured so that it can be applied. The wrinkle holding plate 3 is provided so as to face the die 2. An edge of an embossed aluminum alloy plate (not shown) is sandwiched between a die face (wrinkle holding portion) between the die 2 and the wrinkle holding plate 3.

In this embodiment, a spacer 4 is arranged between the die 2 and the wrinkle holding plate 3. By changing the thickness of the spacer 4, the clearance C 1 between the die 2 and the wrinkle holding plate 3 is changed. Is appropriately adjusted. The spacer 4
It is made of a metal that is harder than an aluminum alloy plate.
The punch 1 is designed and arranged so as to have a clearance C2 between the punch 1 and the die 2.

The aluminum alloy plate to be pressed according to the present embodiment is uniformly embossed as described with reference to FIGS. 1 (a), 1 (b) and FIG. In the present embodiment, the two clearances C1 and C2 are both equal to or more than the emboss height of the aluminum alloy plate, preferably 1.0 to 1.5 of the emboss height.
It is set to double. In the press forming apparatus of the present embodiment, the die 2 is not provided at a position facing the punch 1 along the moving direction of the punch 1, but when this is provided, the die at that portion is not provided. -The clearance between the dies is also set to the emboss height or more, preferably 1.0 to 1.5 times the emboss height.

By pressing the embossed aluminum alloy plate using the press forming apparatus configured as described above, the collapse of unevenness due to the embossing is suppressed, and the forming limit height is increased. Can also be increased. Therefore, according to the press forming method of the present embodiment, it is possible to increase the design freedom of the embossed aluminum alloy plate.

The press forming method according to the present invention can be formed basically irrespective of the thickness within a practical range of the thickness.
More specifically, even if it is an embossed Al alloy plate, it can be applied from a relatively thin plate having a plate thickness of about 0.20 to 0.8 mm to a relatively thick plate. However, the thickness of the Al alloy plate has a greater effect on the properties of the shielding material than on the forming. That is, while the thinner the plate thickness, the lighter the weight can be achieved, cracks occur during the embossing of the Al alloy plate, and the embossing itself becomes difficult. A thicker plate increases bending rigidity as a shielding material, but sacrifices weight reduction. Therefore, it is preferable to appropriately select from the above-mentioned thickness range in consideration of these characteristics and requirements.

Further, as for the embossed (unevenness) height of the embossed Al alloy sheet, similarly to the above-mentioned sheet thickness, the influence on the characteristics of the shielding material is greater than the influence on the forming. That is, when the emboss height is less than 2.0 times the plate thickness, various effects of providing the emboss cannot be obtained, and the characteristics are the same as those of a flat plate. On the other hand, when the emboss height exceeds 5.0 times the plate thickness, cracks occur during the embossing of the Al alloy plate, and the embossing itself becomes difficult. Therefore, in consideration of these characteristics and requirements, it is sufficient to appropriately select an emboss height range from 2.0 to 5.0 times the plate thickness.

[0024]

Embodiments of the present invention will be described below. (Example 1) A 1050 aluminum alloy plate (blank: □ = 100) embossed as shown in FIGS. 1 (a) and 1 (b) using a press forming apparatus as shown in FIG.
mm, a plate thickness of 0.45 mm, and an emboss height of 2.8 mm) were press-molded, and the forming limit height at which unevenness due to embossing was crushed was measured. In this example, cylindrical drawing was performed on an aluminum alloy plate using a cylindrical punch.

At this time, by changing the thickness of the spacer arranged between the die and the wrinkle holding plate, the clearance between the die faces (the clearance between the die and the wrinkle holding plate) is reduced to 0 mm (the ratio of the emboss height to the embossed height is 0 mm). 2. It means that the spacer was not used, and it is considered that the clearance is actually about the thickness of the aluminum alloy plate.) 2.8 mm (ratio to emboss height 1.0); Press molding was performed while changing the thickness to 6 mm (ratio to emboss height: 1.3).

The pressing conditions at this time are as follows: the cylindrical punch has a diameter φp of 40 mm, a punch shoulder radius Rp of 3 mm, a die opening diameter φd of 50.6 mm, and a die shoulder radius of 2 m.
m (5% of the punch width), the wrinkle holding force was 1.0 ton, and a rust preventive cleaning oil (4.0 cst / 40 ° C.) was used as a lubricant between the die and the wrinkle holding plate. Also, the clearance between the die and the punch is 0 mm, so that the clearance between the die faces is the same as the clearance between the die faces.
Press molding was carried out with three types of 8 mm and 3.6 mm.

FIG. 4 shows the results of Example 1. FIG. 4 is a graph showing the relationship between the clearance between the die faces with respect to the embossing height and the forming limit height (mm), in which Δ marks are data obtained in Example 1. Example 1
As is clear from FIG. 4, the forming limit height starts to increase rapidly when the clearance between the die faces with respect to the embossing height exceeds 1.

On the other hand, when the clearance is 1.5 times or more, the wrinkles begin to increase and the clearance becomes 2.0 times.
In the case of double (5.6 mm), overlapping wrinkles occurred frequently, making it difficult to commercialize the product. Therefore, it is preferable that the upper limit of the clearance be 1.5 times the height of the unevenness.

(Embodiment 2) The same embossing as in Embodiment 1 was carried out except that the diameter φd of the die opening was 56.0 mm and the die shoulder radius was 8 mm (20% of the punch width). The pressed aluminum alloy plate was subjected to press forming, and the forming limit height was measured. The result is shown in FIG. In FIG. 4, the mark ● represents the data obtained in Example 2. As is apparent from Example 2, when the clearance between the die faces with respect to the embossing height exceeds 1, the forming limit height starts to increase sharply, and when it exceeds 1.2, it is almost twice as large as the clearance 0. Become.

Judging from Examples 1 and 2, it can be seen that as the value of the die shoulder radius with respect to the punch width increases, the forming limit height increases.

(Example 3) A 1050 aluminum alloy plate (blank: □ = 100 mm, embossed) as shown in FIGS. 1 (a) and 1 (b) using a press forming apparatus as shown in FIG. Press forming was performed on a sheet thickness of 0.45 mm and an emboss height of 2.8 mm), and the forming limit height at which unevenness due to embossing was crushed was measured. In the present embodiment, a square tube drawing was performed on an aluminum alloy plate using a square tube-shaped punch.

Also at this time, by changing the thickness of the spacer, the clearance between the die faces and the clearance between the die punches are reduced to 0 mm, 2.8 mm, and 3.6.
Press molding was carried out while changing the thickness to three types of mm.

The pressing conditions at this time are as follows: the width (length of one side) Dp of the square cylindrical punch having a square shape in a plan view is 40 m.
m, the punch shoulder radius Rp is 5 mm, the punch corner radius is 10 mm, the width Dd of the die opening which is also square in plan view is 48 mm, and the die shoulder radius is 6 mm (15 mm of the punch width).
%), The die corner radius was 14 mm, the wrinkle holding force was 1.0 ton, and a rust-preventive cleaning oil (4.0 cst / 40 ° C.) was used as a lubricant between the die and the wrinkle holding plate.

FIG. 4 shows the results of Example 3. FIG. 4 is a graph showing the relationship between the clearance between the die faces with respect to the embossing height and the forming limit height (mm), in which Δ marks are data obtained in Example 3. Example 3
As is clear from the above, the forming limit height starts to increase rapidly when the clearance between the die faces with respect to the emboss height exceeds 1, as in the case of the cylindrical drawing test.

Judging from Examples 1 to 3 described above, it is possible to increase the molding limit height by setting the clearance between the die faces and the clearance between the die and the punch to be equal to or greater than the emboss height. It can be seen that these clearances are more preferably 1.0 to 1.5 times the emboss height.

The embodiment of the present invention is described above with reference to FIG.
Although the specific embossed shape shown in (b) has been described, it has been found that the present invention can be applied to various other embossed shapes in almost the same manner. Also, 1
For aluminum alloys other than the 050 aluminum alloy, substantially the same results as in the above-described embodiment can be obtained. In addition, the method for press-forming an embossed aluminum alloy sheet of the present invention is applied not only to a shielding plate (heat insulator) of an automobile, but also to the press-forming of various embossed aluminum alloy sheets. It is possible.

[0037]

As described above, according to the present invention,
Even if the press forming is performed so that the forming height is relatively high, the embossing irregularities hardly collapse, and the degree of freedom of the press forming in the embossed aluminum alloy plate can be greatly increased.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an example of an embossed aluminum alloy plate.

FIG. 2 is a schematic diagram of another example of an embossed aluminum alloy plate.

FIG. 3 is a schematic view showing a main part of a press forming apparatus used in a press forming method of an embossed aluminum alloy sheet according to one embodiment of the present invention.

FIG. 4 is a graph showing a relationship between a clearance between die faces with respect to an embossing height and a forming limit height in Examples 1 and 2 of the present invention.

FIG. 5 is a graph showing a relationship between a clearance between die faces with respect to an emboss height and a forming limit height in Example 3 of the present invention.

[Explanation of symbols]

 Reference Signs List 1 punch 2 die 3 wrinkle holding plate 4 spacer

Claims (2)

[Claims] 1. An embossed aluminum alloy characterized in that the clearance between the die faces and the clearance between the die and the punch are formed so as to be equal to or greater than the height of the unevenness imparted to the plate by embossing. Press forming method of plate. 2. The method of press-forming an embossed aluminum alloy sheet according to claim 1, wherein the clearance is 1.0 to 1.5 times the height of the unevenness provided on the sheet by embossing. .