JP2004237314A - Punch for punching square shape and method for manufacturing it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a square-shape punching punch with which the chamfering of each corner part in the punch for punching a square shape in a cross-sectional shape is simultaneously performed and a manufacturing method of it. <P>SOLUTION: The punch 11 for punching the square shape which is square in a cross section and the angles formed in four corners of which are a right angle is constituted so as to perform the chamfering of each corner into a shape a circle of which is drawn by taking radii from the centers O, P of this regular square as the radii RA, RB slightly smaller than the dimension from the centers O, P to each corner C when supposing a regular square taking the short side of the square shape as one side. In the manufacturing method of the punch for punching the square shape, by supposing a regular square taking the shorter side as one side in the punch for punching a square shape which is square in the cross-sectional shape and the angles formed in four corner parts 13 of which are at a right angle, four corner parts 13 of the square shape are simultaneously ground while the punch rotates around the centers O, P of this regular square. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a punching punch having a square or rectangular cross-sectional shape and a manufacturing method thereof, and more specifically, each corner of the quadrangle (a corner at the intersection of the surface) is chamfered in an arc shape. The present invention relates to a punching punch and a manufacturing method thereof.
[0002]
[Prior art]
There are various shapes such as a round shape, a triangular shape, and a quadrangular shape as the cross-sectional shape of a punching punch for punching a metal sheet. However, in a square punch, chipping is likely to occur at the corner portion. In general, a small chamfering process is performed.
[0003]
In a punch with a square cross-section, chamfering is conventionally performed on the corners, and the chamfering is not a flat (slope) chamfering, but a chamfered portion to reduce chipping. Chamfering is performed in an arc shape with a small radius so as to be rounded so as to eliminate. Since this type of chamfering is conventional, the dimension of the minute radius is not necessarily constant, and is generally about 0.1 mm to 0.3 mm.
[0004]
The chamfering of the corner in the square punching punch is customarily performed in consideration of the chipping of the corner and corresponding to the required processing accuracy. There is no literature showing appropriate values for chamfering of each corner.
[0005]
[Problems to be solved by the invention]
Conventionally, when chamfering each corner of a punching punch having a square cross-section, each surface of the corner 3 of the punching punch 1 is rounded with a minute radius R as shown in FIG. The center of rotation A is set at a position of dimension R from 5 and the punching punch 1 is rotated around the center of rotation A to feed it relative to the grindstone so that each corner 3 is arc-shaped chamfered. (Grinding).
[0006]
Therefore, conventionally, in order to chamfer each corner, positioning for aligning the rotation center A of each corner 3 in the punching punch 1 with the rotation center of the jig holding the punching punch 1 is performed for each corner 3. There is a problem that the chamfering of each corner 3 in the punching punch 1 is extremely troublesome.
[0007]
Further, when a micro joint (a punching process that leaves a minute connecting portion between a workpiece and a product) is performed by the conventional punch 1, a portion of the micro joint 7 has a concave shape as shown in FIG. The arcs 3A and 3A formed are opposed to each other, the change rate of the width dimension between the arcs 3A and 3A in the micro joint 7 is large, and the portion of the minimum dimension of the width dimension when the workpiece vibrates. There is a problem that stress concentration occurs in the micro joint and the micro joint is easily detached.
[0008]
[Means for Solving the Problems]
The present invention has been made in view of the conventional problems as described above. The invention according to claim 1 is a square punching punch having a quadrangular cross-sectional shape and a right angle formed by four corners. Assuming a square with a short side as one side, the four corners are formed in a shape in which a circle is drawn with the radius from the center of the square being slightly smaller than the dimension from the center to each corner. It is the structure which performed chamfering.
[0009]
The invention according to claim 2 is a method of manufacturing a square punching punch having a quadrangular cross-sectional shape and a right angle formed by four corners, assuming a square having one side of the short side of the square. Is a method for manufacturing a square punching punch that simultaneously grinds a plurality of adjacent corners in an arc shape while rotating around the center of the center.
[0010]
The invention according to claim 3 is a method for manufacturing a rectangular punching punch according to claim 2, wherein the four corners of the square are simultaneously ground in an arc shape.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 1, the punching punch 11 according to the embodiment of the present invention has a cross-sectional shape of a quadrangle in which each corner portion 13 forms a right angle, and FIG. 1 shows a punching punch having a square cross-sectional shape. The punching punch 11 is centered on a center 0 of a square, and each corner is formed on a circular arc 13A having a radius RA slightly smaller than the dimension from the center 0 to the intersection C of the surface 15 and the surface 15. It is the structure which performed 13 chamfering.
[0012]
More specifically, the radius RA is a radius that describes a circle circumscribing the arc 3A of the conventional radius R. Therefore, although it is approximated when the chamfering process is performed on the slope C inclined with respect to the both surfaces 15 at the intersection C of the surface 15 and the surface 15, it is compared with the chamfering by the slope due to the circular arc. The squared part becomes smaller.
[0013]
The arc 13A is formed by grinding the corners 13 by feeding them relative to the grindstone in a state where the punching punch 11 is rotated around the center 0 of the punching punch 11. Therefore, the four corners 13 of the punching punch 11 are ground simultaneously under the same conditions.
[0014]
Therefore, it is easy to grind each of the four corners 13 in the punching punch 11, and each corner 13 can be machined with the same shape and size with the same high precision, eliminating the conventional problems as described above. Is something that can be done. Since each of the four corners 13 can be machined with the same shape and size with high accuracy, even if the workpiece is punched many times, only one corner is compared with the other corners. Therefore, the local wear that is greatly worn can be suppressed, and as a result, the tool life is increased.
[0015]
With the above-described configuration, when the joint portion between the workpiece and the product is subjected to micro joint processing, the portion of the micro joint 17 is a portion where the arc 13A having a large radius is opposed, and the width dimension of the micro joint 17 portion is the micro joint. Thus, the stress concentration can be avoided as compared with the case of the arc 3A of the conventional radius R.
[0016]
FIG. 2 shows a punch 11A having a rectangular cross section. In this punching punch 11A, a square whose cross-sectional shape is a square having a short side 15S as one side is assumed, and an angle C of intersection of the short side 15S and the long side 15L from the center P about the center P of the square. Chamfering is performed at each corner when a circle is drawn with a radius RB having a dimension slightly smaller than the previous dimension.
[0017]
In the case of the punching punch 11A having a rectangular cross-sectional shape, corners that rotate the punching punch 11A around the center P and perform grinding simultaneously are corners located on both sides of the short side 15S. .
[0018]
【The invention's effect】
As can be understood from the above description, according to the present invention, the punching punch is rotated to grind a plurality of corners simultaneously to perform chamfering, which is compared with conventional chamfering. Thus, chamfering is easy, and a plurality of corners can be chamfered to the same shape and size, and as a result, the tool life can be extended.
[0019]
Moreover, since the arc of the chamfered portion is a large-diameter arc, when microjoint processing is performed, the width dimension of the microjoint portion can be made substantially constant over the entire length of the microjoint portion. Good microjoint processing that can suppress stress concentration can be performed.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing a cross-sectional shape of a punching punch according to a first embodiment of the present invention.
FIG. 2 is an explanatory view showing a cross-sectional shape of a punching punch according to the first embodiment of the present invention.
FIG. 3 is an explanatory view showing a cross-sectional shape of a conventional punching punch.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1,11 ... Punching punch 3,13 ... Corner | angular part 5,15 ... Surface 7,17 ... Micro joint part 3A, 13A ... Arc

Claims (3)

When assuming a square punching punch whose cross-sectional shape is a square and the angle formed by the four corners is a right angle, and the short side of the square is one side, the radius from the center of the square is A square punching punch characterized in that the four corners are chamfered into a shape in which a circle is drawn with a radius slightly smaller than the dimension reaching each corner. A method of manufacturing a rectangular punch having a quadrangular cross-section and a right angle formed by four corners, assuming a square with the short side of the square as one side, and rotating around the center of the square A method for manufacturing a rectangular punch, wherein a plurality of adjacent corners are simultaneously ground in a circular arc shape. A method for manufacturing a rectangular punching punch according to claim 2, wherein the four corners are simultaneously ground in a circular arc shape.

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