JP2001239327A - Drawing method and its drawing die - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drawing method in which there are no scratches due to a roughed outer peripheral surface of a drawn metal plate and there is also no stack of plating layer peeled off from the metal plate to a drawing die, when drawing a corner portion and an edged line portion of a box-like body at a targeted radius R, in the case of drawing a metal plate to the box-like body, and its drawing die. SOLUTION: In a first process, the metal plate 16 is drawn to the box-like body at a radius R (namely, R>=3t) which is equal to and more than three times of the thickness t of the metal plate 16, and which is also practical for drawing. In a second process, an outer peripheral surface 20 of the box-like body drawn in the first process is pounded by a V-shaped punch 17 so that the drawn R (R>=3t) is decreased to meet the targeted R of an end product.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drawing method for drawing a metal plate such as a plated steel plate into a box-like body having corners and ridges, and a mold for forming the same.

[0002]

2. Description of the Related Art Recently, a metal plate such as a plated steel plate, which is easy to recycle due to environmental problems, is used in place of a resin material as a material for home appliances such as a door frame of a microwave oven and a front frame of a television receiver. It is becoming.

Conventionally, a metal plate such as a plated steel plate has been
As shown in the perspective view of the drawn product in (a) and the enlarged perspective view of the same part in FIG. 4 (b), one metal plate 1 having a thickness t is formed by the drawing method on the bottom surface 2 and the outer peripheral side surface 3. Consisting of R
For drawing into a box-like body having a corner 4 and a ridge 5 where (R) = t, as shown in a side sectional view of a conventional drawing die in FIG. An upper die having a pad 10, which is fixed from the upper die holder 6 and slidably slidable within the drawing punch 7 from the upper die holder 6 by a lifting bolt 9 and constantly urged downward by an upper spring 9, An aperture die 12 corresponding to the aperture punch 7 is fixed to a mold holder 11, and the outer periphery of the aperture die 12 is slidable.
First, as shown in the left half of FIG. 5 showing a state in which the upper and lower dies are open, the metal plate 1 is formed by a drawing die composed of a lower die provided with a pad 14 constantly urged upward by 3. Is placed on the drawing die 12 and the pad 14 of the lower mold. Then, as shown in the right half of FIG. 5 showing the state where the upper mold has reached the bottom dead center, the upper mold holder 6 is The metal plate 1 is held between the pad 10 and the lower die 12 by the urging force of the upper spring 9, and when the upper die holder 6 is further lowered, the upper punch 7 of the upper die is lowered. The pad 14 is lowered along the outer periphery of the drawing die 12 against the repulsive force of the lower spring 13 in contact with the pad 14 of the side die, and the drawing punch 7 of the upper die and the drawing die 12 of the lower die are pressed. The metal plate 1 is drawn and formed into a box-like body between them.

As shown in the drawing process top view of FIG. 6 (a) and the drawing process side view of FIG. 6 (b), the conventional drawing process can first draw the metal plate 1 with a first drawing punch. After the first drawing step of drawing the outer peripheral side surface 3 with a size R ₁ (R), R ₁ is sequentially reduced in size while ironing the outer peripheral side surface 3 with a second drawing punch similar in shape to the first drawing punch. A second squeezing step for squeezing the target R ₂ (R) was performed.

[0005]

However, in order to squeeze a metal plate into a box-like body at a radius (R) aimed at corners and ridges by the above-described conventional drawing method and the forming die. Because the outer peripheral side is drawn many times while squeezing the outer peripheral side, the outer peripheral side of the metal plate is rough and scratched, especially in the case of a plated metal plate such as a plated steel plate, the plating peels off, There was a problem that the next product was damaged by the mold.

The present invention solves the above-mentioned problem. Even if the corners and ridges of a box-shaped body are drawn and formed with R (R), the narrowed outer peripheral side surface is roughened and damaged. It is an object of the present invention to provide a draw forming method and a forming die in which a plated metal plate such as a plated steel plate does not peel off and adhere to a die.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a drawing method for drawing a metal plate into a box-like body having corners and ridges. In the process, R (R) ≧ 3t, which is at least three times the thickness t of the metal plate
In a second step, a metal plate is drawn and formed in a box shape, and in the second step, the outer peripheral side surface of the box shape drawn and formed in the first step is punched with a punch.
(R) ≧ 3t is reduced to make the target R of the final product
(R) is a drawing method.

As a result, the outer peripheral side surface of the drawn box-shaped body is roughened and damaged, and even when the metal plate constituting the box-shaped body is a plated steel plate, the plating is peeled off and adheres to the mold. There is no one.

[0009]

DETAILED DESCRIPTION OF THE INVENTION The invention according to claim 1 of the present invention is a drawing method for drawing a metal plate into a box-like body having corners and ridges, wherein the first step comprises the steps of: The metal plate is drawn and formed into a box-like body with R (R) ≧ 3t which is three times or more the thickness t of the metal plate, and in a second step, the outer peripheral side surface of the box-shaped body drawn and drawn in the first step is punched. Tapping R (R) ≧ 3
This is a draw forming method in which t is reduced to form the desired R (R) of the final product. In the second step, the outer peripheral side surface of the box is hit by a punch to squeeze the outer peripheral side of the box. R (R) of size that can be squeezed ≧ 3t
Has the effect of forming into the desired R (R) of the final product.

According to a second aspect of the present invention, there is provided a drawing method for drawing a metal plate into a box-like body having corners and ridges. The metal plate is drawn and formed into a box-like body so that the angle with the part is within 5 degrees. In the second step, the outer peripheral side of the box-shaped body drawn and drawn in the first step is punched with a punch to obtain a final product. Target R
(R). In the first step, the metal plate is drawn into a box-like body so that the angle between the corner and the ridgeline is within 5 degrees. When the outer peripheral side surface of the box-shaped body is hit with a punch in the process, there is an effect that the metal plate has no excess, no corners are wrinkled, and a clean R (round) is obtained.

According to a third aspect of the present invention, there is provided a punch for forming a box-shaped body drawn and formed in the first step into a box-shaped R as a final product in a second step; Corresponding to punch, box-shaped R as final product
3. A drawing die used in the drawing method according to claim 1 or 2, comprising a die adapted to (R), wherein a punch and a die form a box-shaped body as a final product.
(R).

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment) FIG. 1 is a plan view of a forming die used in a drawing method according to an embodiment of the present invention, FIG. 2 is a side view of the forming die, and 15 is a drawing die of FIG. In the first step, R (R) of a size that can be drawn, that is, R that is three times or more the thickness t of the metal plate 16 to be drawn.
(R) The corners of the box-shaped body formed by drawing and forming the metal plate 16 with ≧ 3t, and the second step 17 is to use the corners 15 of the box-shaped body drawn and formed in the first step in the box as the final product. A V-shaped punch 19 used for forming R (R) = t, which is R (R) of a corner 18 of the shape, corresponds to the V-shaped punch 17 and is a corner of a box-shaped body as a final product. A die adjusted to R (R) = t of the portion 18, and a box-shaped body drawn by R (R) ≧ 3t of a size that can be drawn in the first step is covered with a die 19 to form a box-shaped body. Outer side surface 20 is V
R (R) ≧ 3t
From the corners 18 of the final product.

FIGS. 3A and 3B are diagrams showing a forming process of a box-shaped body drawn by the drawing method in the above embodiment. FIG. 3A illustrates the forming process from a plane, and FIG. 3B shows the forming process. This will be described from the side. In the first step using the drawing die shown in FIG. 5, R (R) having a size that can be drawn,
That is, R (R) ≧ 3t which is at least three times the thickness t of the metal plate 16 to be drawn, and R (R) ≧ 3
The metal plate 16 is drawn into a box-like body so that the angle between the corner 15 of t and the ridge 21 is within 5 degrees, and in the second step, the V-shaped punch 17 in FIGS. Hit the outer peripheral side surface 20 of the corner 15 of the box-shaped body, and R (R) ≧ 3t
From the corners 18 of the final product.

In the first step, the corner 15 of the box-shaped body is
(R) ≧ 3t is the reason why the metal plate 1
When the aperture 6 is squeezed at 1 degree, it is a limit that the corner 15 is not broken.
This is because 5 may be broken. Until the metal material was improved recently, R (R) ≧ (4 to 6) t was satisfied (see “Press Drawing”, published by Nikkan Kogyo Shimbun, Akira Hashimoto, p. 32, etc.).

The reason why the angle between the corner 15 of the box-shaped body and the ridge 21 in the first step is set to 5 degrees or less is that if the angle is set to 5 degrees or more, the corner 15 will protrude too much. When the outer peripheral side surface 20 of the corner 15 is hit with the V-shaped punch 17 in two steps to form the target corner 18, the metal plate 16 is used.
This is because there is a problem that excessive flesh is formed, wrinkles are formed on the corners 18, and a clean R cannot be obtained.

Also, in this embodiment, an example in which the draw forming method is applied to the corners 15 and 18 of the box-like body has been described. Needless to say.

As described above, according to the draw forming method of the present embodiment, when the metal plate 16 is drawn into a box-like body having the corner portions 15 and 18 and the ridge portion 21, the corner portion is formed in the first step. 15 and the ridge 21 are squeezable R (R) ≧ 3t, and the angle between the corner 15 and the ridge 21 is narrowed to within 5 degrees. Then, in the second step, the V-shaped punch 17 forms a box. The outer peripheral side surface 20 of the body is a corner portion 18 and a ridge line portion 21 of tapping R (t) = t. Since the outer peripheral side surface 20 of the box-shaped body is not very hard in the second step, the outer peripheral side surface 20 becomes rough. Thus, even if the metal plate 16 is a plated steel plate, the plating does not peel off and adhere to the mold.

[0019]

As described above, according to the draw forming method and the forming die of the present invention, R (R) is used for the corners and ridges of a box-shaped body formed by drawing a metal plate. ), The outer peripheral side surface of the box-shaped body is not roughened and damaged, and even when the metal plate constituting the box-shaped body is a plated steel plate, the plating is peeled off and adheres to the mold. No effect is obtained.

[Brief description of the drawings]

FIG. 1 is a plan view of a molding die used in a drawing method according to an embodiment of the present invention.

FIG. 2 is a side view of a molding die used in a drawing method according to an embodiment of the present invention.

FIG. 3 is a process chart of forming a box-shaped body drawn by a drawing method according to an embodiment of the present invention.

4A is a perspective view of a drawn product, and FIG. 4B is a partially enlarged perspective view of FIG.

FIG. 5 is a side sectional view of a conventional drawing die.

6A is a top view of a conventional drawing process, and FIG. 6B is a side view of a conventional drawing process.

[Explanation of symbols]

 1,16 Metal plate 2 Bottom surface 3,20 Outer side surface 4,15,18 Corner 5,21 Ridge 6 Upper die holder 7 Drawing punch 8 Hanging bolt 9 Upper spring 10,14 Pad 11 Lower die holder 12 Drawing die 13 Lower Spring 17 V-shaped punch 19 Die

Claims (3)

[Claims] 1. A drawing method for drawing a metal plate into a box-shaped body having corners and ridges, wherein, in a first step, R (R) is at least three times the thickness t of the metal plate. ) The metal plate is drawn and formed into a box-like body with ≧ 3t, and in the second step, the outer peripheral side of the box-shaped body drawn and drawn in the first step is punched with a punch to reduce R (R) ≧ 3t to reduce the final product. A draw forming method for forming a target R (R). 2. A drawing method for drawing a metal plate into a box-shaped body having corners and ridges, wherein the angle between the corners and the ridges in the first step is within 5 degrees. Then, the metal plate is drawn into a box-shaped body, and in a second step, the outer peripheral side surface of the box-shaped body drawn and drawn in the first step is beaten with a punch to form an R (R) as a final product. Drawing method. 3. A punch for forming the box-shaped body drawn and formed in the first step into R (R) of a box-shaped body as a final product in a second step, and a box as a final product corresponding to the punch. The draw forming die used in the draw forming method according to claim 1 or 2, comprising a die adjusted to R (R) of the shaped body.