JPH0122052B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a hole punching method for punching a hole by pushing a punch into a workpiece without a hole.

(Prior art) Conventionally, a workpiece is held between a die having a scrap relief passage and a presser pad located outside the punch, with the punched part facing the scrap relief passage, and the punched part is punched. A hole punching method is known in which a hole is punched by punching with a .

With this conventional method, reference numeral 1 in FIG.
When processing a product in which the punching width Y accounts for a large proportion of the product width X, the punching process is performed as shown in FIGS. 2 and 3.

First, the method shown in FIG. 2 will be described. Reference numeral 2 denotes a conventional punch, 3 a die having a relief hole 4 as a scrap escape passage, and 5 a presser pad. Here, the product 1 is shown punched out from the back.

By the way, in the press direction shown in this figure,
The process before and after the main hole punching process is that since the orientation of the product 1 is reversed, a reversal operation is required to reverse the orientation of the product 1 before and after the main hole punching process. This results in a problem of reduced efficiency.

Furthermore, the shapes of the parts of the die 3 and presser pad 5 that press down the product 1 are made to match the shape of the product 1 in order to position the product 1 with respect to the punch 2. Therefore, here, the wall thickness of the die 3 is not limited, but since the tip of the presser pad 5 is located between the punch 2 and the portion near the tip of the die 3, the wall thickness is limited. This causes the problem that the strength tends to be insufficient.

Next, the method shown in FIG. 3 will be described. In this figure, 6 is a punch, 7 is a die having a relief hole 8 as a scrap escape passage, and 9 is a presser pad. Here, the product 1 is shown punched out from the front.

Since the press direction shown in this figure is the same as the direction of the product 1 in the steps before and after the main hole punching step, reversing work can be avoided. Further, the thickness of the presser pad 9 is not limited. However, the strength of the part near the tip of the die 7 where the product 1 is set must be ensured to the extent that it can withstand the impact during punching, so the size of the relief hole 8, that is, the width, is restricted. Therefore, there is a problem that the punching width is restricted.

(Object of the invention) In view of the problems of the above-mentioned prior art, the present invention has been made to:
It is an object of the present invention to provide a hole punching method that can simultaneously solve the lack of strength of a die and a presser pad without requiring reversing work of the workpiece and without restricting the width of the hole to be punched. shall be.

(Means for Solving the Problems) Therefore, in the present invention, cutting is started from both ends of the perforated portion of the workpiece, and the cut pieces are passed through the scrap relief passage toward the center. The cutting progresses while pushing and bending inward in the width direction of the workpiece, and the central part remaining after the final cut is cut, so that the scrap after punching is smaller than the width of the punched part of the workpiece. It is characterized by

(Example) Hereinafter, an example of the hole punching method according to the present invention will be described with reference to the drawings together with the apparatus used.

FIG. 4 shows a hole punching device used in the method of the present invention. In this figure, reference numeral 10 indicates a punch formed to perform the method of the present invention, and 11
1 is a die having a scrap relief hole 12 as a scrap relief passage, and 13 is a presser pad located outside the punch 10.

At the tip of the punch 10, a double-end cutting blade portion 10A is formed at an edge corresponding to both ends of the punched portion of the product 1 in the width Y direction.
A side cutting blade portion 10B is formed inwardly with an inclination so as to gradually cut the punched portion toward the center as the punch 10 descends. The innermost part of the side cutting blade part 10B contacts the base of the cut piece cut by the both-end cutting blade part 10A and the side cutting blade part 10B, so that the innermost part of the scrap relief hole 12 is moved inward in the width direction of the scrap relief hole 12. It is made into the pushing bending part 10C which pushes and bends. This pressing part 10
A stepped portion is formed on the inside of C to form a recessed portion, and the side edge of the recessed portion is the final cutting blade portion 10D.

Here, since the press direction is for punching out the front side of the product 1, the portion near the tip of the die 11 where the product 1 is set is formed to match the shape of the product 1. The side end of the scrap relief hole 12 of this die 11 near the punch 10 is
0 and is formed to be a punch driving permissible hole 12A, and this punch driving permissible hole 12A
The length is slightly longer than the length between the both end cutting blade portion 10A and the final cutting blade portion 10D of the punch 10. The inner peripheral surface of the die 11 located below the punching permissible hole 12A has a tapered shape that becomes thicker as it goes downward. The portion is narrower than the punch 10, and
It is formed to be slightly wider than the width between the pushing bending parts 10C and 10C of the punch 10.

The presser pad 13 is formed to have a wall thickness that is not limited and provides sufficient strength.

Next, FIGS.
This will be explained with reference to FIG. 7 as well.

First, as shown in FIG. 5, a workpiece 1', which will become the product 1 before punching, is set on the die 11, and
Press the workpiece 1' with the presser pad 13,
The workpiece 1' is attached to the die 11 and the presser pad 13.
to hold. At this time, depending on the shape of the die 11, the workpiece 1' is positioned so that the punched portion faces the scrap relief hole 12.

After the workpiece 1' is set in the device, the punch 10 is lowered, and as shown in FIG. It is cut toward the center by section 10B to form cut piece 1B'.

Further, the punch 10 is lowered to bring the pressing portion 10C into contact with the base of the cut piece 1B' and press the base, as shown in FIG. Press and bend inward in the width direction.

Then, the punch 10 is further lowered and the remaining part of the uncut center part of the punched part is punched.
By pressing the final cutting blade 10D and punching out as shown in FIG. 4, the punching process is completed. The maximum dimension of the scrap 1C formed at this time decreases from Y to y.

In other words, since the scrap 1C can be made smaller, the width of the scrap escape hole 12 can be made narrower to compensate for the smaller size.
1 can be formed with a configuration in which the wall thickness increases. As a result, the lack of strength of the die 11 in the pressing direction in which holes are punched from the front side of the product 1 without the need for reversing the product 1 is resolved.
This problem of insufficient strength of both the die 11 and the presser pad 13 can be solved at the same time.

Furthermore, since the scrap 1C can be made smaller, the outflow treatment can be carried out smoothly.
can also be used as is in other products, such as patches.

(Effects of the Invention) As explained above, according to the present invention, the maximum dimension of the scrap can be made smaller than the hole punched part of the workpiece before the hole is punched, so the scrap relief passage can be made narrower by that amount. This means that it can be formed as follows. This makes it possible to overcome the lack of strength of the die without using a press direction that requires reversing the workpiece. This eliminates the need for reversing the workpiece and limits the punching width. This has the effect that the insufficient strength of the die and the presser pad can be solved at the same time without being damaged.

[Brief explanation of drawings]

Fig. 1 is a perspective view of a product obtained by punching holes in a workpiece, Figs. 2 and 3 are explanatory diagrams of a conventional hole punching method, and Fig. 4 shows holes used in the method of the present invention. 5 to 7, which are cross-sectional views of the punching device, are explanatory diagrams for explaining the method of the present invention. 1...Product, 1'...Work material, 1B'...Cut piece, 1C...Scrap, 10...Punch, 10
A...Both end cutting blade part, 10B... Side cutting blade part,
10C...Press bending part, 10D...Final cutting blade part, 1
1... Dice, 12... Scrap hole, 13
...The presser foot is padded.

Claims (1)

[Claims] 1 Place the workpiece into a die having a scrap relief passage and a presser pad located around the punch.
The punch is held so that the punched part faces the scrap relief passage, and the punch, whose lower end is shaped unevenly in the width direction, is lowered, and the punch first punches out the punched part using the convex part, leaving the center part. Then, the cut pieces are pressed and bent inward in the width direction of the scrap relief passage using the stepped portion between the convex portion and the concave portion, and the central portion of the remaining cut portion is inserted into the concave portion. A hole punching method that involves twisting, cutting, and punching holes.