JPH05154576A - Punching die - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a press punching die capable of ejecting a punching piece of a work material without trouble to obtain a good product and preventing damage to the die. [Structure] A plurality of convex portions 7 or concave portions are formed in an inner peripheral wall 6a of a through hole 6 of a die 4 along a punching direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a press punching die suitable for punching machine parts and components of electronic equipment with high precision.

[0002]

2. Description of the Related Art A press punching die for punching a work piece placed on a die by a punch extruded by a press machine is more precise and finer with the progress of die material and die working technology. Punching has become possible.

However, even at the present time when fine processing is realized, there remains a problem that the punching piece adheres to the punch side and moves to the work piece mounting surface side of the die, so-called scrap rising phenomenon cannot be eliminated. It was When this scrap rises, the material to be next punched and the punched piece are punched together by punching, and the inner peripheral edge of the hole formed in the workpiece and the outer peripheral edge of the punched piece are deformed, resulting in a defective product. The following problems occur. In addition, when punching pieces are punched repeatedly,
Since the punch and the die are burdened, the life of the punch and die is reduced, and there is a problem that the punch and the die are damaged if the punched pieces are repeatedly punched in a state of being displaced from the center of the punch.

Therefore, various measures have been proposed for preventing the above-mentioned scrap rising, and FIG. 5 shows a press punching die as an example.

In this press punching die 10, a through hole 11a is formed in a die 11 which is a fixed die and a punch 12 which is a movable die is inserted. 11b is a through hole 1
It is a tapered surface provided on the lower side of 1a. Also, die 11
A gap G is provided between the punch 12 and the punch 12 in an amount determined according to the thickness t of the workpiece 1. Further, this press punching die 10 has an air introduction hole 13 having an opening on the bottom surface 12a of the punch 12, and the punch 1
The high pressure air can be pumped toward the bottom surface 12a of the second.

The press punching die 10 is designed to push out the punch 12 by a press machine (not shown) to punch the workpiece 1 placed on the die 11. As a result, when the workpiece 1 is punched out, holes having the same sectional shape as the punch are formed. Further, when the high-pressure air is blown when the work piece 1 is punched with the punch 12, the punched piece 2 can be separated from the punch 12. In this case, in order to discharge the punched piece 2 more effectively, it is known that a suction device is provided on the die 11 side to suck the punched piece 2.

Further, the press punching die 20 shown in FIG.
As described above, a guide hole 22a is formed on the punch 22 side instead of the above-mentioned means for blowing high-pressure air.
There is also used a knockout pin 23 that advances and retreats along 2a so that the punched piece 2 is ejected and ejected.

However, when the press punching dies 10 and 20 shown in FIGS. 5 and 6 are used to make holes in the workpiece 1 in units of several millimeters, the punch 1 having a small diameter is used.
It is necessary to form the air introduction hole 13 and the guide hole 22a in the Nos. 2 and 22. Usually, it is difficult to punch a long hole in a punch made of steel, and if the punch provided with this processing is provided and a high-pressure air supply device, a vacuum device, etc. are attached, the manufacturing cost of the entire device becomes expensive. There was a flaw.

Further, the press punching die 20 shown in FIG.
As described above, in the case where the knockout pin 23 is provided, it is necessary to provide the cushioning means 24 and the like for absorbing the impact of the knockout pin 23, which increases the number of constituent parts and complicates the structure to make the mold more easily. It was difficult.

Therefore, the press punching die 3 shown in FIG.
0 is suggested. This is the through hole 3 of the die 31.
A tapered surface 31b having an inner diameter that gradually increases is provided on the lower side of 1a to facilitate the drop of the punched piece 2 after punching.

However, the press punching die 30 is
Although it is effective for discharging the punched piece 2, the inner peripheral wall of the through hole 31a not forming the tapered surface 31b has a short length in the punching direction. Thus, since the stroke length of the punch 32 is short, there is a drawback that the finish when the punched piece 2 is a product is poor.

The press punching die 40 shown in FIG. 8 has been proposed in order to solve this problem. In the through hole 41a of the die 41, the length of the inner peripheral wall not forming the tapered surface 41b is increased. A tapered surface 41c having a gradually increasing inner diameter is provided from this portion toward the opening of the through hole 41a. As a result, there is an advantage that the punching piece 2 easily adheres to the inner peripheral wall that does not form the tapered surface 41c, and the problem that the punching piece 2 adheres to the punch 42 and rises can be suppressed.

However, the press punching die 40 is
When the work material 1 is sheared by the punch 42, the inner peripheral edge 42a of the work material 1 is bent in the punching direction, and large sags and burrs are generated. There was a problem that had an adverse effect on.

The press punching die 50 shown in FIG. 9 is an improvement of the above-mentioned conventional example and is an inner wall surface 51 of the through hole 51a of the die 51.
b is provided with unevenness to make it a rough surface, and the friction resistance of the punching piece 2 that descends the through hole 51a is increased to make the punching piece 2 an inner wall surface 5
It is intended to be closely attached to 1b.

However, this press punching die 5
When 0 is used for a long time, the convex portion of the concave-convex surface 51b is scraped off, the adhesion effect is significantly reduced, and the die 51 needs to be replaced more frequently.

The press punching die 60 shown in FIG.
Unlike these, the gap G between the die 61 and the punch 62 is made smaller to prevent the punching piece 2 from rising. For example, when the gap G is set to 2 to 3% t or less of the plate thickness of the workpiece 1, the springback amount of the punched piece 2, that is, the degree of restoration due to the elastic force after the bending deformation becomes large and the inner peripheral wall 61b is punched. Since the piece 2 strongly adheres, it is effective for preventing the punched piece 2 from rising.

[0017]

However, in the conventional press punching die 60, the punch 6 is formed in the through hole 61a.
When 2 moves downward, the frictional force between the inner peripheral wall 61b of the through hole 62 and the outer peripheral edge 2a of the punched piece 2 also increases, so that the punched piece 2 is easily clogged, and many punched pieces 2 stay in the through hole 61a. There was a problem that it would not be discharged.

An object of the present invention is to solve the above problems.

[0019]

According to the present invention, in order to achieve the above object, a punch is formed in a die through which a punch is inserted, and a work piece placed on the die is extruded by a press machine. The press punching die for punching is characterized in that a plurality of convex portions or concave portions are formed in the inner peripheral wall of the through hole of the die along the punching direction.

[0020]

According to the present invention, since the plurality of convex portions or concave portions are formed along the punching direction on the inner peripheral wall of the through hole of the die, the inner peripheral wall of the die is provided with an uneven surface. Therefore, when the punch is inserted into the die, a wide gap and a narrow gap are generated.

When the work material is placed on the die and the punch is extruded by the press machine to punch the work material with the punch, the work material is sheared by the pressing force of the punch. At this time, a hole having the same shape as the punch is formed in the work material, and the punched piece is projected while being curved and deformed.

When the punched piece returns to its original shape in the through hole, the outer diameter becomes slightly larger than the inner diameter of the inner peripheral wall of the die.
Therefore, the outer peripheral edge of the punching piece is pressed against the inner peripheral wall of the die corresponding to the narrow gap, and the die is brought into close contact with the inner peripheral wall.

On the other hand, in the wide gap, a gap is formed between the outer peripheral edge of the punched piece and the inner peripheral wall.

Therefore, air flows between the through hole and the upper and lower parts of the die through the gap. Thus, when the punch is pulled up after punching, a vacuum state is not formed in the through hole, and the punching piece does not come into close contact with the lower surface of the punch and rise.

Then, when the punch is inserted into the through hole next time, the punching piece is pushed out in the punching direction by the air pressure caused by the movement of the punching piece punched by the punch, and is discharged without being clogged in the through hole. To be done.

[0026]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a vertical sectional view of a press punching die.

In this press punching die 3, a through hole 6 is formed in a die (fixed side die) 4, and a punch (movable side die) 5 inserted into this through hole 6 is extruded by a press machine not shown. The work piece 1 placed on the die 4 is punched out.

In the through hole 6 of the die 4, as shown in FIG. 2, three convex portions 7 are formed on the inner peripheral wall 6a along the punching direction of the workpiece 1. These convex portions 7 are provided at equal distances, and the top surface of each convex portion 7 is formed to have the same curvature as the inner peripheral wall 6 a of the through hole 6.

The punch 5 has a circular cross section, and the outer diameter is slightly smaller than the inner diameter of the through hole 6 on the top surface of the convex portion 7, and the inner peripheral wall 6a of the through hole 6 and the outer peripheral wall 5a of the punch 5 are formed.
A small gap G is formed between the and. The gap G has a narrow region W1 narrowed by the convex portion 7 provided on the inner peripheral wall 6a and a wide region W2 widened by the absence of the convex portion 7.

The two gap regions W1 and W2 may have a plurality of convex portions 7 to form a large number of regions. Further, not only the convex portion 7 is provided on the inner peripheral wall 6a, but a plurality of concave portions 7 may be formed on the inner peripheral wall 6a to form the gap regions W1 and W2.

In the present example, the ratio of the narrow region W1 and the wide region W2 is set in the range of W1: W2 = 1: 15 to 1: 5. For this ratio, an optimum value is selected in accordance with the punched shape of the workpiece 1, the material, the thickness, the condition of the gap G, and the like.
Further, each gap G in the narrow region W1 and the wide region W2 is determined by the value of% t with respect to the thickness t of the workpiece 1.

Next, the press punching step will be described.

When the work material 1 is placed on the die 4 and the punch 5 is extruded by the press machine to punch the work material 1 with the punch 5, as shown in FIG. It is pressed and sheared. Then, a hole having the same shape as the die 4 is formed in the work material 1, while the punch 5 is formed.
The punching piece 2 that is ejected by is pushed into the through hole 6. At this time, the punching piece 2 is curved and deformed because it is pressed by the punch 5, and the outer diameter is slightly smaller than the inner diameter of the inner peripheral wall 6 a of the die 4.

When the punched piece 2 is spring-back, that is, flattened by the elastic deformation force, it is punched out into the same shape as the punch 5, but the outer diameter of the inner peripheral wall 7a on the top surface of the convex portion 7 is the same. It is slightly larger than the inner diameter.
Therefore, the outer peripheral edge 2a of the punched piece 2 is pressed against the inner peripheral wall 7a, and the inner peripheral wall 7a comes into close contact with the inner peripheral wall 7a.

On the other hand, a wide region W2 is formed between the inner peripheral wall 6a where the convex portion 7 is not provided and the outer peripheral edge 2a of the punched piece 2.

Then, the wide area W is formed in the through hole 6.
Since a flow passage through which air flows is formed via 2, the vacuum state is not formed between the punching piece 2 immediately after punching and the punching piece 2 before. Moreover, when the punch 5 is pulled up after punching, the work material 1 rises together with the punch 5, and a gap is created between the upper surface 4a of the die 4 and the lower surface 1a of the work material 1, so Air also circulates between the through holes 6 and the punching piece 2 does not come into close contact with the lower surface 5 a of the punch 5 and rise.

Then, when the workpiece 1 is next punched, the punched piece 2 is pushed out by the air pressure due to the movement of the punched piece 2, and is discharged without being clogged in the through hole 6.

Therefore, when the punch 5 is pulled up after punching as in the conventional case, the punching piece 2 is placed on the upper surface 4 of the die 4.
It is possible to prevent the problem that the workpiece 1 is moved to a and is struck with the work piece 1 repeatedly, resulting in a product defect, the die 4 or the punch 5.
It avoids the problem of damage.

In the press punching die 3, the punching piece is set by setting% t, which determines each gap between the narrow region W1 and the wide region W2, to an optimum value according to the thickness of the workpiece 1. It is possible to discharge 2 without any trouble and to take out a good quality product.

FIG. 4 is a graph showing the relationship of finishing of products when% t is changed.

In the figure, the vertical axis represents the outer diameter of the punched piece 2 when the inner diameter of the through hole 6 of the die 4 is set to a reference value of 0, and the + side is the outer diameter of the punched piece 2 rather than the inner diameter of the through hole 6. The diameter is large, and the minus side indicates that the outer diameter of the punched piece 2 is smaller than the inner diameter of the through hole 6.

The horizontal axis represents% t which sets the gap between the die 4 and the punch 5. Here, W1 is the gap in the narrow region, W2 is the gap in the wide region, and S is the punching piece 2
It is the outer diameter change characteristic of.

The plus side on the vertical axis means that when the workpiece 1 is punched by the punch 5 as described above,
After the punching piece 2 is bent once and then restored to a flat shape,
This is because the outer diameter of the punched piece 2 is larger than the inner diameter of the through hole 6. At this time, the outer peripheral edge of the punched piece 2 is pressed against the inner peripheral wall 6a of the through hole 6 to maintain a close contact state.

As is clear from FIG. 4, the smaller the% t in the narrow region W1, the larger the outer diameter of the punched piece 2 is than the inner diameter of the through hole 6, and when% t is about 3, the inner diameter of the through hole 6 is small. Is equal to Further, in the wide area W2, when% t is set to about 7 or more, the outer diameter of the punched piece 2 is stable at a value slightly smaller than the inner diameter of the through hole 6, indicating that a good product can be obtained. Then, when% t exceeds about 25, the outer diameter of the punched piece 2 with respect to the inner diameter of the through hole 6 becomes smaller, and burrs and sags are generated in the product, resulting in a defective product.

Therefore, it is most preferable to set% t to about 7 in order to take out a good product without any trouble in discharging the punched piece 2.

[0047]

As described above, according to the present invention, when a plurality of convex portions or concave portions are formed in the inner peripheral wall of the through hole of the die along the punching direction and the punch is inserted into the die,
Since a wide gap and a narrow gap are created, when the work material is punched out, the outer peripheral edge of the punched piece is pressed against the inner peripheral wall corresponding to the narrow gap, resulting in a close contact. While being kept, air can be circulated in the wide gap.

Therefore, when the punch is pulled up after punching, since the vacuum state is not formed in the through hole, the punching piece does not move to the upper surface of the die as in the conventional case, and the punch is then inserted into the through hole. When punched, the punched piece is ejected without clogging the through hole.

Further, the problem of repeatedly punching the work piece and the punched piece is prevented, and the problem of damaging the die and punch is avoided. Further, since a plurality of convex portions or concave portions are provided on the inner peripheral wall of the through hole of the die, the structure is simple. In particular, when forming a convex portion, it is possible to adopt a wire cut electric discharge machine that builds up by electric discharge while moving the wire along the inner peripheral wall of the punch, so that the mold can be manufactured easily and the manufacturing cost is also low. effective.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a press punching die according to an embodiment of the present invention.

2 is a cross-sectional view taken along the line AA of FIG.

FIG. 3 is an explanatory view showing a discharged state of punched pieces.

FIG. 4 is a graph showing that die-punch clearance is related to product finish.

FIG. 5 is a vertical cross-sectional view showing a press punching die of Modification 1 of the related art.

FIG. 6 is a vertical cross-sectional view showing a conventional press punching die of Modification 2;

FIG. 7 is a vertical cross-sectional view showing a conventional press punching die of Modification 3;

FIG. 8 is a vertical cross-sectional view showing a conventional press punching die of Modification 4;

FIG. 9 is a vertical cross-sectional view showing a press punching die of Modification 5 of the related art.

FIG. 10 is a vertical cross-sectional view showing a conventional press punching die of Modification 6;

[Explanation of symbols]

 1 Work Material 2 Punching Piece 3 Press Punching Die 4 Die 5 Punch 6 Through Hole 7 Convex Part G Gap

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shuichi Hamada 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (1)

[Claims] 1. A press punching die in which a through hole through which a punch is inserted is formed in a die, and a workpiece placed on the die is punched out by a punch extruded by a press machine, wherein an inner peripheral wall of the through hole of the die. In the press punching die, a plurality of convex portions or concave portions are formed along the punching direction.