JP2002178047A - Die - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the yield of a vessel by integrating parts for performing drawing and ironing step by step with one die to minimize friction flaws generated in an outer circumferential surface of the vessel forced in the die. SOLUTION: In a deep-drawing die comprising a punch 10 of required shape and a die 12 with the punch 10 inserted therein, the die 12 comprises a first die 16 located on an upper part and a second die 18 located below the first die 16 and arranged in the axial direction. A second clearance B forming a minimum distance between an inner circumferential surface of the second die 18 and an outer circumferential surface of the punch 10 is set to be slightly smaller than a first clearance forming a minimum distance between an inner circumferential surface of the first die 16 and the outer circumferential surface of the punch 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die,
More particularly, the present invention relates to a die for drawing a bottomed cylindrical container for a battery.

[0002]

2. Description of the Related Art In order to manufacture a cylindrical bottomed container represented by, for example, an AA battery, a metal sheet is pressed in a deep drawing step by a press machine and formed into a cup shape. 2. Description of the Related Art A press machine for forming a finished intermediate product into a predetermined shape by so-called ironing is generally known. This ironing itself can make the thickness of the side wall of the cylindrical container thinner than the bottom of the can or improve the finish of the can. As a specific process, a cup-shaped intermediate product formed to a required depth by one drawing process is passed through the punch to a die in which a clearance smaller than a side wall thickness of the intermediate product is defined when the punch is inserted. It is performed by forcibly pushing it.

As shown in FIG. 3, the die 20 in this case is formed into a tapered shape at a required angle from the inner peripheral edge of the opening toward the inner diameter direction.
A hollow portion 20b having a required inner diameter is formed along the axial direction. However, a portion where the tapered portion 20a and the hollow portion 20b are continuous is, as shown in an enlarged view in FIG.
c. Further, the outer diameter of the punch 22 inserted into the die 20 is such that the clearance defined between the outer diameter of the die 20 and the portion where the inner diameter of the die 20 is minimized (that is, the inner end portion of the arc-shaped portion 20c) is the intermediate diameter. The dimension is set to be smaller than the thickness of the product 24 by a required amount.

Accordingly, the intermediate product 24 formed in a cup shape is pressed by the punch 22 at the bottom thereof, and the die 2 is pressed.
0, the side wall of the product 24 is pressed by the tapered portion 20a to reduce the diameter.
At the same time as the so-called drawing, the so-called ironing to reduce the thickness of the side wall of the product 24 is performed simultaneously with the punch 22 at the inner end portion of the drawing diameter. In addition, a multi-stage die in which a plurality of dies having different drawing diameters are connected in series in the order of reducing the diameter of the can body has been put into practical use, and according to this transfer drawing process, a die corresponding to each die is passed through. In addition, the cup-shaped intermediate product 24 can be formed into a bottomed cylindrical container as a final product in one step.

[0005]

In the above-mentioned battery container as an example, in recent years, there has been a request from a battery manufacturer of a delivery destination to make the plate thickness of the container side wall with respect to the bottom of the can smaller. The reason for this is to increase the capacity of the battery material by reducing the plate thickness, and to improve the efficiency of the battery. However, in the die 20 and the punch 22 in which the above-described drawing and ironing are simultaneously performed with a one-step drawing diameter, there is a limit in increasing the plate pressure difference (plate thickness reduction ratio) between the bottom of the can and the side wall of the container. The reason is that when drawing and ironing are performed, the contact area of the side wall with the tapered portion 20a and the arc-shaped portion 20c increases, so that the outer peripheral surface is formed while the side wall slides with these. This may cause considerable friction scratches. As a result, the surface roughness of the surface of the battery container is increased, and it is necessary to set a large coating film in a later process, and there are disadvantages such as a decrease in product value and a decrease in yield.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems inherent in the prior art, and has been proposed in order to solve the problem in a suitable manner. By integrally forming the part to be applied integrally, frictional scratches generated on the outer peripheral surface of the container formed by pressing the die are minimized, the yield of the container is improved, and the side wall of the container is made thinner. It is an object of the present invention to provide a die that can be formed to improve the capacity of a battery material.

[0007]

[MEANS FOR SOLVING THE PROBLEMS]
A die according to the present invention for suitably achieving the intended purpose is a punch having a required shape and a die for deep drawing composed of a die into which the punch is inserted.
The first die is located above and the second die is located below the first die and is axially aligned. The first die is located between the inner peripheral surface of the first die and the outer peripheral surface of the punch. The second clearance, which is the shortest distance between the inner peripheral surface of the second die and the outer peripheral surface of the punch, is set to be slightly smaller than the first clearance, which is the shortest distance. .

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the dice according to the present invention will be described below with reference to the accompanying drawings. As shown in FIG. 1, the die according to the embodiment includes a punch 10 having a required shape and a die 12 into which the punch 10 is inserted. As an example, a deep drawing application capable of forming a bottomed cylindrical battery container. Is configured. The die 12 includes a cylindrical main body base 14 having a hollow portion 14 a, a first die 16 which is axially aligned on the base 14, and is placed on the upper side, and a lower surface of the first die 16. It is basically composed of a second die 18 arranged.

That is, as shown in FIG. 2, the first die 16 mounted on the main body base 14 has a tapered portion 16a common to that described in the prior art, and an arc-like shape set to a stop diameter of a required curvature. It is configured as an integral member having a portion 16b. As shown in FIG. 2, a first clearance A is defined in a portion of the first die 16 which forms the shortest distance between the inner peripheral surface of the arcuate portion 16 b and the outer peripheral surface of the punch 10. The first clearance A is set in advance so as to be substantially the same as the thickness of the side wall portion of the intermediate product 24.

A second die 18 separate from the first die 16 is a substantially ring-shaped member. As shown in FIG. 1, the second die 18 is concentric with the hollow portion 14a from the upper end of the main body base 14. Notch-formed ring-shaped steps 14 of required depth
b so as to be closely fitted and accommodated. As shown in FIG. 1, the second die 18 is fixed to the ring-shaped stepped portion 14b while the first die 16 is placed on the second die 18 while the first die 16 is placed on the second die 18. 16c
The bolt 17 inserted through the female hole 14
This is done by screwing into c. However, in the embodiment, the first
The die 16 and the second die 18 have a separate structure. However, this is because the manufacture is easy, and it goes without saying that both the dies 16 and 18 may be manufactured integrally. .

The inner surface of the hollow portion 18a in the axial direction of the second die 18 is set to an inner diameter such that the lower end thereof is aligned with the inner surface of the hollow portion 14a when placed in the ring-shaped step portion 14b. At the same time, the portion extending from the lower end portion to the upper end portion is formed so as to have a diameter slightly smaller than the inner diameter. On the inner peripheral edge of the upper end of the second die 18, an arc-shaped portion 18b (described later with reference to FIG. 2) having a required curvature that contributes to a reduction in the thickness of the side wall of the intermediate product 24 is formed. A portion of the inner peripheral surface is formed along the axis from the inner end closest to the heart. The inner peripheral surface along this axis is a portion generally called a bearing, and the upper end of the inner peripheral surface whose diameter is reduced is formed so as to intersect and continue with the bearing.

That is, the arc-shaped portion 18b is a portion formed with a sufficiently smaller curvature than the arc-shaped portion 16b of the first die 16, and is formed as a hollow portion 14a in the main body base 14.
(The upper end of the bearing)
However, it is set to be slightly closer to the outer peripheral surface of the punch 10 than to the end portion of the arcuate portion 16b formed on the first die 16. In this case, as shown in FIG. 2, a second clearance B is defined at a portion that forms the shortest distance between the bearing that is the inner peripheral surface of the second die 18 and the outer peripheral surface of the punch 10. The second clearance B is set slightly smaller than the first clearance A defined between the first die 16 and the punch 10.

[0013]

Next, the operation of the above-described die will be described. The intermediate product 24 molded into a cup shape,
By being pushed into the hollow portion 14a provided in the main body base 14 via the punch 10 formed as a pair with the die 12, the side wall portion comes into contact with the tapered portion 16a of the first die 16 and drawing is performed. Is applied. That is, as shown in FIG. 2, the side wall of the intermediate product 24 pushed in the axial direction of the hollow portion 14a along the tapered portion 16a formed on the first die 16 is circular from a required position of the tapered portion 16a. Sliding across the arcuate portion 16b reduces its inner diameter dimension. In this case, the first clearance A defined between the end of the arcuate portion 16b and the punch 10 is set to have a width substantially equal to the thickness of the side wall of the battery container as described above. I have. Therefore the first
No ironing is performed when passing through the clearance A.

The side wall portion reduced in diameter after passing through the first clearance A temporarily separates from the inner side surface when moving downstream from the end portion of the arc-shaped portion 16b and is formed immediately below the downstream side in the pushing direction. Arc-shaped portion 18b of the second die 18
Contact with a very slight time difference. This arc-shaped portion 18b
As described above, the arc-shaped portion 16b of the first die 16
And projecting slightly closer to the axial center direction of the hollow portion 14a than the inner terminal end portion. For this reason, as shown in FIG. 2, the outer peripheral surface of the side wall portion that has passed through the end portion of the arc-shaped portion 16b contacts the arc-shaped portion 18b from the upstream side in the pushing direction and slides on the peripheral surface. After being compressed in this way, it passes through a second clearance B defined between the second die 18 and the punch 10.

The portion where the second clearance B is formed is:
The side wall portion that has passed through the second clearance B corresponds to the bearing extending along the axial direction, and the hollow portion 18a of the second die 18 that expands toward the downstream side thereof , The so-called ironing process for reducing the thickness of the container side wall is completed. Even when the first die 16 and the second die 18 are integrally formed, the drawing and the ironing are smoothly performed as in the case of the separate type.

[0016]

As described above, in the die according to the present invention, drawing and ironing are divided into two stages in one die. As a result, in the drawing, the contact area of the side wall of the intermediate product with the inner surface of the first die is reduced, and even in the ironing performed with a slight time lag after the drawing, the side wall is kept in the first state. Since the inner surface of the second die contacts the inner surface of the second die after being separated from the die, frictional scratches are extremely reduced, and the yield is improved because the surface roughness is kept low. Further, there is an advantage that the side wall portion of the container can be easily formed to be thinner, which can contribute to an improvement in the accommodation amount of the battery material.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a die according to a preferred embodiment of the present invention, together with a punch inserted into a hollow portion thereof.

FIG. 2 is a vertical sectional view of a main part of the dice according to the embodiment shown in FIG. 1, in which an intermediate product is inserted through a first die and a second die.

FIG. 3 is a longitudinal sectional view showing a die according to the related art together with a punch inserted into a hollow portion thereof.

FIG. 4 is a longitudinal sectional view of a main part of a die according to the prior art, showing an intermediate product inserted into a hollow portion.

[Explanation of symbols]

 Reference Signs List 10 punch 12 dice 16 1st dice 18 2nd dice A 1st clearance B 2nd clearance

Claims (3)

[Claims] 1. A punch (10) having a required shape, and the punch (10)
Is a die for deep drawing consisting of a die (12) through which the die (12) is located, a first die (16) located above,
A second die (18) positioned below the first die (16) and aligned in the axial direction; and an inner peripheral surface of the first die (16) and an outer peripheral surface of the punch (10). The second clearance (B), which is the shortest distance between the inner peripheral surface of the second die (18) and the outer peripheral surface of the punch (10), with respect to the first clearance (A), which is the shortest distance between ) Is configured to be set slightly smaller. 2. The first die (16) and the second die (1).
8. The dice according to claim 1, wherein each of the dies is formed separately. 3. The first die (16) and the second die (1).
The die according to claim 1, wherein 8) is integrally formed.