JP3128748B2 - Punching method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a punching method and, more particularly, to a punching method in which a plate having a shape whose outer peripheral surface is inclined with respect to both surfaces, such as a valve plate used for an exhaust brake, is formed by shearing. It is about the method.

An exhaust brake opens and closes an exhaust passage in an exhaust pipe by rotating a valve plate rotatably disposed in an exhaust pipe of an engine, and the valve plate is moved with respect to an axis of the exhaust pipe. The exhaust gas passage is closed in an inclined state. Therefore, the valve plate is provided by the actual open flat 3-5.
947, 3-15831, etc., the outer peripheral surface of the circular plate has a shape inclined with respect to both surfaces of the plate.

[0003]

2. Description of the Related Art FIG. 10 shows a conventional apparatus for forming a plate having an outer peripheral surface inclined with respect to both sides, such as a valve plate of the above-mentioned exhaust brake, by punching. The configuration of the mold and the punching method will be described. Lower mold 102
Is a die 108 fixed on a die holder 104 via a die spacer 106 and a circular hole 1 of the die 108.
08a, and a knockout 110 fitted so as to be able to move up and down. The die 108 is provided with a cutting edge portion 108c having an inclination corresponding to an angle formed between both surfaces of the above-mentioned valve plate and the outer peripheral surface with respect to the vertical direction over the entire periphery of the upper end surface of the hole 108a. Therefore, a portion 108ca (right side in the figure) located above the inclined cutting edge 108c has an obtuse angle, and a portion 108cb located below has an acute angle.

The knockout 110 has a surface 110a for supporting a workpiece 112 at an upper end thereof,
Of the blade edge portion 108c of the same. The knockout 110 is connected to an air cylinder (not shown) via a rod 114 fixed to the bottom, and is constantly urged upward by a weak air pressure supplied to the air cylinder. A large-diameter stopper portion 110b is provided on the outer periphery of the knockout 110, and the die 108
The work supporting surface 110a is located in the same plane as the cutting edge 108c of the die 108 at the highest position.

On the other hand, an upper die 115 is a punch 118 fixed to a punch holder 116 which is connected to a machine and moves up and down.
And the guide 120 is fitted around the punch 118.
And a stripper 122 which can be moved up and down relatively through the. The punch 118 is provided at the edge 1 of the die 108.
08c and work support surface 110 of knockout 110
The processing surface 118a has a slope that matches the slope of the cutting surface 118a, and a cutting edge 118b is provided over the entire outer circumference of the processing surface 118a. In the cutting edge portion 118b, an upper portion 118ba (right side in FIG. 10) has an obtuse angle, and a lower portion 118bb (left side in FIG. 10).
Has an acute angle. The outer diameter of the punch 118 is
8 is slightly smaller than the inner diameter of the hole 108a,
When the workpiece 112 is inserted into the die 108 when descending and punching the workpiece 112, a slight clearance is formed between the die 108 and the inner peripheral surface of the hole 108a of the die 108.

The stripper 122 fitted on the outer periphery of the punch 118 is positioned outside the obtuse portion 118ba (right side in FIG. 10) of the cutting edge 118b of the punch 118 with respect to the inclined processing surface 118a of the punch 118. And the portion located outside the acute angle portion 118bb (the left side in FIG. 10) are on the same inclined surface . Na you, in this conventional apparatus, in order to prevent the punch 118 and the die 108 may cause misalignment when performing punching,
The lifting and lowering of the punch holder 116 is guided by a guide post 130.

With the conventional punching device according to the above configuration,
When shearing a plate having an inclined cutout such as a valve plate of an exhaust brake, first, a circular plate-shaped workpiece 112 is arranged on the knockout 110 and the die 108 at the rising end. This work 112 is a general circular plate in which the angle between both surfaces of the plate and the outer peripheral surface is a right angle. Work 112
A small hole 110d is formed in the vicinity of the center, and is positioned by a fixing pin 113 embedded on the support surface 110a of the knockout 110. The work 112 has an area larger than the surface area of the work supporting surface 110a of the knockout 110, and the entire periphery thereof protrudes toward the surrounding die 108 while being fixed on the work supporting surface 110a (2 in FIG. 10). See dash-dot line). In this state, the punch 118 is lowered together with the punch holder 116. The punch 118 descends and hits the work 112, and this work 1
While pushing 12 into the die 108, the outer periphery of the work 112 is sheared over the entire periphery by the cutting edge portion 118b of the punch 118 and the cutting edge portion 108c of the die 108 to obtain a desired shape.

[0008]

In the above-mentioned conventional configuration,
Both the die 108 and the punch 118 have a cutting edge 1 that covers the entire circumference.
08c, 118b, and since these cutting edges 108c, 118b are inclined with respect to the direction (vertical direction) in which the punch 118 moves, both of them have acute angles 108c, 118b with the cutting edges 108c, 118b. 118
bb. Such a sharp edge 108c
Since b and 118bb have lower strength than the obtuse or right-angled cutting edge, there is a possibility that tooth spilling or breakage may occur due to repeated use.

The present invention has been made in order to eliminate the above-mentioned disadvantages. A cutting edge is formed at an obtuse or right angle portion of a die and a punch, and punching is performed using only this portion. It is an object of the present invention to provide a punching method that is not used for processing and prevents breakage of a cutting edge or tooth spillage.

[0010]

According to the present invention, there is provided a punching method, wherein an outer peripheral surface of a plate-like work is punched while being inclined with respect to both surfaces of the work, and a cutting edge provided on a die is provided. Part and at least one of the cutting edge portions provided on the punch are inclined, and a punching process is performed using a cutting edge portion other than an acute angle portion of the die and the punch, that is, a right-angle or obtuse angle cutting edge portion. The plate is rotated, and the punching process is repeated with a right-angled edge portion or an obtuse-angled edge portion other than the acute angle portion of the die and the punch, so that the entire outer peripheral surface of the plate-shaped work is inclined and punched out. .

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view showing an example of an embodiment of a press die used for carrying out a punching method according to the present invention, and FIG. 2 is a perspective view showing its components separately. First, FIG. A schematic configuration will be described.
The lower die (indicated by reference numeral 2 as a whole) of the device is fitted to a die 8 fixed via a die spacer 6 arranged on a die holder 4 and a hole 8a inside the die 8 so as to be able to move up and down. Knockout 10. The upper surface (work supporting surface) 10a of the knockout 10 has a slope equal to the angle formed between the side surface and the outer surface of a plate whose outer peripheral surface used for a valve plate or the like of an exhaust brake is inclined with respect to the side surface. A plurality of fixing pins 13 are embedded in the work support surface 10a of the knockout 10, and the work 1 placed on the support surface 10a
2 is fixed and supported so as not to move.

On the other hand, the upper surface 8b of the die 8 is horizontal, and the upper edge of the internal hole 8a in which the knockout 10 is fitted has a half circumference (the right side in FIG. 1) where the upper side of the knockout 10 is located. ), The cutting edge 8c having a semicircular arc shape
Is provided. The knockout 10 is connected to an air cylinder (not shown) via a rod 14 fixed to the bottom similarly to the above-described conventional device, and is constantly urged upward by a weak air pressure introduced into the cylinder, The large-diameter stopper portion 10b formed on the lower outer periphery hits the lower surface 8d of the die 8 and stops. When the knockout 10 is stopped in this manner, at least the right half of FIG. 1 protrudes above the upper surface 8 b of the die 8.

An upper die (as a whole, denoted by reference numeral 15) of the above apparatus is fitted to a punch 18 fixed to a punch holder 16 which is connected to driving means (not shown) and moves up and down, and fitted around the outer periphery of the punch 18. A stripper 22 is provided, which is guided by a rod 20 and can move up and down relative to the punch 18. The punch 18 has an outer shape substantially matching the shape of the outer peripheral surface of the knockout 10, that is, the hole 8a of the die 8.
Has an outer shape that substantially matches the shape of the inner peripheral surface of the die 8, and fits into the inside of the hole 8 a of the die 8 while pushing down the knockout 10 supporting the work 12 when descending. The lower processing surface 18a of the punch has the same inclination as that of the work supporting surface 10a of the knockout 10, and a portion (right side in the drawing) located above the processing surface 18a has a half circumference. Together with the cutting edge 8c of the die 8, a cutting edge 18b for shearing the work 12 is formed.
Therefore, the cutting edge 18b of the punch 18 has an obtuse angle, and the sharp portion 18e (left side in the drawing) is not subjected to shearing. A hole 1 is formed near the center of the processing surface 18a of the punch 18 to avoid interference with the tip of a fixing pin 13 for fixing the work 12 on the knockout 10.
8c is formed.

The lower surface 22a of the stripper 22 fitted on the outer peripheral side of the punch 18 is a horizontal surface like the upper surface 8b of the die 8, and when it is lowered, it comes into contact with the upper surface 8b of the die 8. . The stripper 22 is used for the punch 18
Around the portion where the blade tip 18b is provided,
2b is formed to accommodate a scrap 12a which is cut off when performing punching. Further, when the punch 18 is lifted after the completion of the shearing process, the stepped portion 22c above the concave portion 22b is separated from the work 12 by the scrap 12 attached to the outer surface of the punch 18.
a is scraped off.

Next, an example of a specific shape of each component of the stamping press die will be described with reference to FIG. The inner hole 8a of the die 8 is such that the right half 8aa in the figure has a small diameter semi-circular shape and the left half 8ab has a large diameter semi-circular shape. The small diameter portion 8aa is slightly longer than the large diameter portion 8ab,
The upper edge of the small-diameter portion 8aa constitutes the cutting edge 8c.

The knockout 10, which is fitted into the internal hole 8a of the die 8 so as to be able to move up and down, has an external surface shape 10c that matches the shape of the internal surface of the internal hole 8a of the die 8, and the right half of FIG. 10ca is a small-diameter arc, and the left half 10cb is a large-diameter arc. For this reason, the rotation of the knockout 10 is restricted at the time of the work punching. As described above, the work supporting surface 10a of the knockout 10
Has an inclination corresponding to the angle formed by the outer surface of the surface after cutting. In the work supporting surface 10a of the knockout 10, two fixing pin mounting holes 10d are provided, and the fixing pins 13 mounted in these holes 10d are provided.
Thus, the movement and rotation of the work 12 to be machined are regulated.

Work 12 processed by this device
Has a circular shape as a whole, and its both surfaces 12b and the outer peripheral surface 12c are perpendicular to each other. In this work 12,
Two fixing pins 1 attached to the knockout 10
Two through-holes 12d into which the three tips are inserted are formed. As the through hole 12d, a hole provided in advance for fixing to the rotating shaft of the exhaust brake can be used (see Japanese Utility Model Laid-Open No. 3-5947, Japanese Utility Model Laid-Open No. 3-25831, etc.). As shown in FIG. 3, the radius of the circular work 12 is larger than the radius of the small-diameter portion 10ca of the knockout 10 (substantially coincides with the small-diameter portion 8aa of the die 8). 10 cb (substantially coincident with the large diameter portion 8ab of the die 8).
Is placed on the work supporting surface 10a of the knockout 10 and fixed by the two fixing pins 13, the protrusion protrudes outward from the small diameter portion 10ca of the knockout 10 and the large diameter portion 1ca.
At 0cb, it is located inside the outer surface.

The upper punch 18 is provided with the knockout 1
0 and an outer peripheral shape 18d that matches the shape of the inner surface 8a of the die 8. That is,
A small-diameter arc-shaped portion 18 slightly longer than the right half of the figure.
da and a large-diameter arc-shaped portion 18db slightly shorter than the semicircle on the left side of the figure. The work surface 18a of the punch 18 is the work support surface 10a of the knockout 10.
And has the same inclination as that of the small-diameter arc-shaped portion 18d.
a is located on the upper side of the slope. The outer periphery of the lower end of the small-diameter arc-shaped portion 18da constitutes a cutting edge portion 18b for performing a shearing process on the work 12 together with the cutting edge portion 8c of the die 8. Therefore, the cutting edge portion 18b of the punch 18 is on the upper side of the slope, that is, an obtuse angle portion, and the acute angle portion 1 on the lower side of the slope.
8e constitutes a guide portion that does not perform shearing.

The stripper 22, which is fitted on the outer periphery of the punch 18 and can be moved up and down relatively,
And a circular hole 22d having a radius equal to the radius of the large-diameter portion 18db of the punch 18 is formed in the center of the horizontal surface. Therefore, the inner surface of the stripper 22 is
A gap (constituting the concave portion 22b in FIG. 1) is provided for the small diameter portion 18da of FIG.

A description will be given of a shearing step using the stamping die having the above-described structure. The upper die 15 is raised to the uppermost position, and the knockout 10 is also raised by an air cylinder (not shown). In this example, the entire work supporting surface 10a of the knockout 10 projects above the upper surface 8b of the die 8. The work 12 is placed on the work supporting surface 10a of the knockout 10, and the head of the fixing pin 13 is inserted and fixed in the through hole 12d of the work 12 (the state of FIG. 4). In this state, the portion overlapping the small diameter portion 10ca of the knockout 10 of the work 12 protrudes outward from the small diameter portion 10ca, and the portion overlapping the large diameter portion 10cb is located inside the large diameter portion 10cb. I have.

Here, the punch 18 and the stripper 22
The upper die 15 provided with is lowered. Punch 1 descending
8 has an inclination that matches the inclination of the knockout 10 and the work 12 fixed on the knockout 10, so that almost the entire surface of the work 1
2 and the work 12 and the knockout 10 are pushed down as it descends. At this point, work 1
2 is before being pressed against the die 8 and the knockout 1
In the case of 0, the air cylinder descends while discharging the air, so that a lateral component force hardly acts on the punch.

While the punch 8 is descending without generating a large component force, the acute angle portion 18e on the large diameter portion 18db side of the punch 8 enters the large diameter portion 8ab side of the hole 8a of the die 8 as it is. After that, the large diameter portion 18d of the punch 18
b is guided by the inner surface of the hole 8ab on the large diameter side of the die 8 and descends. Knockout 1 due to lowering of punch 18
The part of the work 12 that has been pushed down along with the outer diameter side of the small-diameter portion 10ca of the knockout 10 is pressed against the cutting edge 8c of the die 8 (see FIG. 5 showing a state immediately before the start of shearing). At this point, the shearing is started, and the cutting edge 1 at the tip of the punch 18 on the side of the small diameter portion 18da is
8b and a cutting edge 8c formed at the upper end of the inner hole 8a of the die 8 on the side of the small diameter portion 8aa. Punching is performed (FIG. 6 shows a state in the middle of shearing, and FIG. 7 shows a state after the end of shearing). Shown). Note that the shearing is started from the position of S ₁ in FIG. 3, gradually moving to the right in FIG. 3, and ends at the position of S _2.

After the completion of the shearing, the punch 18 is raised, and at the same time, air is supplied to an air cylinder (not shown) to raise the knockout 10. The stripper 22 fitted to the outer peripheral side of the punch 18 is stopped at the lowered position, and the scrap 12 adhered to the outer surface of the punch 18 at the time of shearing.
a is scraped off by the step 22c on the inner surface of the stripper 22 (see FIG. 8).

When the above-described punching step is performed, the circular work material 12 (see FIG. 9A) is cut substantially half the circumference to have the shape shown in FIG. 9B. Next, the work 12 is removed from the work support surface 10a of
After rotating by 0 degrees, the work supporting surface 10 is again turned over .
a. Here, as in the first step,
The steps from FIG. 5 to FIG. 9 are performed. By the second step, the work 12 is subjected to the shearing processing for the remaining half circumference to have the shape shown in FIG. 9C. As described above, the cutting process is performed in two times by using only the right-angled edge 8c and the obtuse-angled edge 18b of the die 8 and the punch 18, so that a load is applied to an acute-angled portion having low strength. There is no possibility that this portion is damaged.

The shapes of the punch 18, die 8, knockout 10 and the like constituting the present apparatus are not limited to those shown in FIG. 2, but may be other configurations. In any case, only the obtuse or right-angled cutting edges of the die 8 and the punch 18 may be used for shearing, and the acute-angled portions may not be used for shearing. For example, the upper surface of the die 8 is not perpendicular as in the above-described embodiment, but has a smaller inclination than the inclination of the processing surface of the punch 18 with respect to the vertical direction, and a cutting edge portion is formed at an obtuse angle portion of the die. Alternatively, the shearing process may be performed. Also, as in the above embodiment, 2
The processing is not limited to cutting the entire circumference of the work 12 by one shearing step, but the processing of the entire circumference of the work 12 may be performed by repeating the steps three or more times.

[0026]

As described above, according to the present invention, in a punching method for punching an outer peripheral surface of a plate-shaped work by inclining the outer surface of the work with respect to both surfaces of the work, a cutting edge provided on a die is provided. At least one of the cutting edge portions provided on the punch is inclined, punching is performed at a cutting edge portion other than the acute angle portion of the die and the punch, and then the work is rotated, and further, the die and the punch other than the acute angle portion of the punch are formed. Since the entire outer peripheral surface of the plate-shaped workpiece is punched by performing the punching process by the part, the sharp edge part is not used for the punching process, so the damage of the cutting edge part or tooth rubbing may occur. Can be prevented.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of a stamping press die used for carrying out a stamping method according to an embodiment of the present invention.

FIG. 2 is a perspective view showing each part of the press die for punching separately.

FIG. 3 is a cross-sectional view of the stamping press die.

FIG. 4 is a view showing a process of punching using the press die for punching, showing a first stage thereof.

FIG. 5 is a view showing a step of punching using the above-described press die for punching, and shows a second stage thereof.

FIG. 6 is a view showing a step of the punching process using the press die for the punching process, and shows a third stage thereof.

FIG. 7 is a view showing a step of the punching process using the press die for the punching process, and shows a fourth stage thereof.

FIG. 8 is a view showing a step of the punching process using the press die for the punching process, and shows a fifth stage thereof.

FIG. 9 is a view sequentially showing a change in the shape of a workpiece subjected to shearing by the punching method.

FIG. 10 is a longitudinal sectional view showing a stamping press die used for carrying out a conventional stamping method.

[Explanation of symbols]

 Reference Signs List 8 die 8c die edge 12 work 12b both sides of work 12c outer peripheral surface of work 18 punch 18b punch edge of punch

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B21D 28/00 B21D 28/14

Claims (5)

(57) [Claims] 1. A punching method in which an outer peripheral surface of a plate-shaped work is punched while being inclined with respect to both surfaces of the work, at least one of a cutting edge provided on a die and a cutting edge provided on a punch. One side is inclined, punching is performed at the edge of the die and punch other than the acute angle portion, then the work is rotated, and further, punching is performed at a portion other than the acute angle portion of the die and the punch to form a plate. A punching method characterized by inclining the entire outer peripheral surface of the workpiece. 2. The method according to claim 1, wherein a half of the outer periphery of the work is performed by one punching step, and the remaining half of the outer periphery of the work is punched by a second step. The stamping method according to 1. 3. The punched surface is inclined with respect to the vertical direction, a cutting edge is formed only on the upper side of the inclination, and punching is performed by the obtuse cutting edge. Punching method described in 1. 4. The punching method according to claim 3, wherein the upper surface of the die is horizontal, a cutting edge portion is formed at a portion facing the cutting edge portion of the punch, and the punching process is performed by the both cutting edge portions. Processing method. 5. The upper surface of the die has an inclination smaller than the inclination of the punch with respect to the vertical direction, and a cutting edge portion is formed at a portion facing the cutting edge portion of the punch. 4. Processing is performed.
Punching method described in 1.