JP2000263150A - Punching die - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce generation of a recess due to pressing the stripper grounding part of an elastic body layer laminated on the inner face of an iron plate and to reduce an external appearance defect of a punched iron plate by making the grounding part of a stripper fitted into a punch to an annular shape with a narrow width along its inner periphery. SOLUTION: A cylindrical stripper 3 is fitted to the tip of a punch 2, a helical spring 4 is inserted between a head part 21 of the punch 2 and the stripper 3. One cutting edge shaped annular projecting line 31, in which the outer wall is inclined along the inner peripheral wall, is arranged to the bottom face of the stripper 3, a grounding part is made to an annular shape with a narrow width along the inner periphery. In punching, the iron plate 5, in which an elastic body 6 of synthetic rubber, synthetic resin, etc., are laminated on one face, is placed on a die 1 with the elastic body up, the head part 21 of the punch is pressed down. The stripper 3 compresses the spring 4 to be stopped on the iron plate 5. When pressing of the punch 2 is stopped, the punch 2 is ascended in the stripper 3 by the spring 4, the iron plate 5 is released.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a punching die.

[0002]

2. Description of the Related Art Conventionally, when punching holes in an iron plate or the like having a thickness of 9 mm or less, a punching die composed of a punch and a die is used, but a stripper is fitted to the punch so that the iron plate does not bite into the punch. For example, JP-A-62-1
No. 58536 and the like.

[0003]

However, when using such a punching die to punch a hole in an iron plate having an elastic body such as synthetic rubber or synthetic resin laminated on one side, it is pressed by a stripper. There is a problem in that the elastic layer is dented and the appearance is impaired.

The present invention solves the above-mentioned conventional problems, reduces the occurrence of dents in the elastic layer laminated on one side of the iron plate due to the pressing of the grounding portion of the stripper, and reduces the appearance defect of the iron plate due to punching. An object of the present invention is to provide a punching die that can be reduced.

[0005]

According to a first aspect of the present invention, there is provided a punching die comprising a punch and a die.
The grounding portion of the stripper fitted to the punch has a narrow annular shape along the inner periphery thereof.

A punching die according to a second aspect of the present invention is further characterized in that the cross section of the grounding portion of the punch has a single-blade shape with an inclined inner wall.

In the punching die according to the first aspect of the present invention, the shape of the grounding portion of the stripper is not particularly limited.
Even if the entire bottom surface of the stripper is chamfered to a single-edged cross section with an inclined outer wall, an annular ridge having a single-edged cross section or a substantially strip-shaped cross section with an inclined outer wall is provided along the inner peripheral wall of the stripper. Or any of them.

The height of the annular ridge is preferably 0.8 to 1.0 times the thickness of the elastic body laminated on the iron plate to be punched. When the thickness of the elastic body is 2 mm, the height is 1.6 to 2.0 times. mm.

In the punching die according to the second aspect of the present invention, the shape of the recess surrounded by the grounding portion of the punch is not particularly limited. For example, the shape may be flat or spherical. Or any of them. The depth of the recess is preferably 0.8 to 1.0 times the thickness of the elastic body laminated on the iron plate to be punched, similarly to the height of the annular ridge described above.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a punching die according to the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing a first embodiment of a punching die according to the first aspect of the invention, FIG. 2 is a cross-sectional view showing a second embodiment of the punching die of the first aspect, and FIG. FIG. 4 is a cross-sectional view showing a third embodiment of the punching die according to the first aspect of the present invention, and FIG. 4 is a cross-sectional view showing one example of the punching die according to the second aspect of the present invention.

In the first embodiment of the punching die according to the present invention shown in FIG. 1, reference numeral 1 denotes a cylindrical die;
Is a rod-shaped punch having a large-diameter head 21. The difference between the inner diameter of the die 1 and the outer diameter of the punch 2 is usually 0.2 to
It is 0.1 mm.

A substantially cylindrical stripper 3 is fitted to the tip of the punch 2, and a helical spring 4 is sandwiched between the head 21 of the punch 2 and the stripper 3. On the bottom surface of the stripper 3, an annular ridge 31 having a single-blade cross section with an outer wall inclined along the inner peripheral wall is provided, and the ground contact portion is formed in a narrow annular shape along the inner periphery.

When punching a hole, an iron plate 5 having an elastic body 6 such as synthetic rubber or synthetic resin laminated on one side is placed on the die 1 with the elastic body layer facing upward. Decrease 21. The stripper 3 stops on the iron plate 5 while compressing the spring 4, and only the punch 2 descends and penetrates the iron plate 5.

When the pressing of the head 21 of the punch 2 is stopped,
The punch 2 rises and restores inside the stripper 3 by the elasticity of the spring 4, and the iron plate 5 attached around the punch 2
It is separated from the punch 2 by the stripper 3.

In a second embodiment of the punching die according to the first aspect of the present invention shown in FIG. 2, the entire bottom surface of the stripper 3 is chamfered into a single-blade cross section with an inclined outer wall, and is grounded. Except that the portion is formed in a narrow annular shape along the inner periphery thereof, it is the same as the first embodiment, and the description is omitted.

In a third embodiment of the punching die according to the present invention shown in FIG. 3, an annular ridge 31 having a substantially rectangular cross section is formed on the bottom surface of the stripper 3 along the inner peripheral wall. Is provided in the same manner as in the first embodiment except that the grounding portion is formed in a narrow annular shape along the inner circumference thereof, and therefore the description is omitted.

In one embodiment of the punching die according to the second aspect of the present invention shown in FIG. 4, the cross section of the grounding portion 22 of the punch 2 has a single blade shape with an inclined inner wall. Grounding part 22
Except that the elastic body 6 laminated on the iron plate 5 can be accommodated in the recessed portion surrounded by, the description is omitted because it is similar to the first embodiment.

[0018]

The punching die according to the first aspect of the present invention is configured as described above, so that the depression of the elastic layer laminated on one side of the iron plate due to the pressing of the ground portion of the stripper is prevented. It is possible to reduce the number of defects and to reduce the appearance defect of the iron plate due to the punching. Since the punching die according to the second aspect of the present invention is configured as described above, in addition, the elastic body in the hole portion is deformed to the outside at the time of punching and does not protrude outside the punch. ,
The appearance of the cut surface can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of a punching die according to the present invention;

FIG. 2 is a sectional view showing a second embodiment of the punching die according to the first embodiment of the present invention;

FIG. 3 is a sectional view showing a third embodiment of the punching die according to the present invention;

FIG. 4 is a sectional view showing an example of a punching die according to the invention of claim 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Die 2 Punch 3 Stripper 4 Spring 5 Iron plate 6 Elastic body 21 Punch head 22 Punch ground part 31 Ring ridge

Claims (2)

[Claims] 1. A hole punching die comprising a punch and a die, wherein a grounding portion of a stripper fitted to the punch is formed in a narrow annular shape along an inner periphery thereof. Cutting die. 2. The punching die according to claim 1, wherein the cross section of the grounding portion of the punch has a single blade shape with an inclined inner wall.