JPH0515378Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention is suitable for ring-shaped workpieces, especially thick-walled ring-shaped workpieces whose wall thickness changes greatly toward the inner circumference in the axial direction. The present invention relates to a drilling die suitable for use in drilling a predetermined portion including a thick portion.

(Prior art) Conventional drilling dies of this type have a die and a punch whose end faces correspond to the shapes of the outer circumferential surface and the inner circumferential surface of a ring-shaped workpiece, respectively. There is a type that can make surface contact with the outer and inner circumferential surfaces of the workpiece.Drilling with such a die involves applying the end face of the punch to the entire required drilling part of the ring-shaped workpiece supported on the die. This was done by making surface contact and punching out the entire part almost simultaneously.

Here, the clearance between the die and the punch is generally 5 to 15% of the thickness of the workpiece.

(Problem to be solved by the invention) By the way, in this conventional technique, the shape of the tip of the punch corresponds to the shape of the inner circumferential surface of the workpiece, so the shape of the inner circumferential surface is complicated. For large workpieces, the shape of the end face of the punch becomes complicated, which significantly increases the manufacturing cost of the punch and the entire drilling die.In addition, stress concentrates on the sharp parts of the punch end face and other areas, resulting in chipping or other damage. The problem was that it was easy to occur.

And here, during drilling, the shear resistance of the thicker part of the workpiece is considerably greater than that of other parts, which causes a stress dispersion effect on the punch tip surface, and from the thicker part of the workpiece to the thinner part. Due to stress acting on the tip of the punch due to plastic flow, an external force acts on the punch in the prying direction, resulting in wear and tear due to galling between the side of the punch and the circumferential surface of the punched hole. There is a problem in that the durability of the punch and the machining accuracy of the hole machining are significantly reduced due to welding and other phenomena occurring in the punch. Another problem was that a press machine with a large capacity had to be used because punching was performed at the same time.

This invention advantageously solves the problems of the conventional technology, and not only allows drilling with sufficient precision to be performed over a long period of time, but also significantly reduces manufacturing costs, and eliminates the problem of punch breakage and other problems. To provide a highly durable drilling die that effectively prevents damage to the press and allows use of a small-capacity press machine.

(Means for Solving the Problems) The drilling die of this invention has two parts, in particular, on the tip surface of the punch that cooperates with the die, which simultaneously abuts the inner circumferential surface of the workpiece at both ends in the axial direction of the workpiece. It is provided with two protruding cutting blades.

(Function) In this drilling type, by bringing the punch close to the inner circumferential surface of the ring-shaped work while the die is in surface contact with the outer circumferential surface of the ring-shaped workpiece, the tip of the punch is first cut into two protrusions. The blade cuts the workpiece at two locations in the axial direction of the workpiece, and more preferably, the protruding cutter blade provided around the entire circumference of the tip of the punch cuts the workpiece only at the edge of the required drilling portion of the workpiece. simultaneously inscribed on the inner circumferential surface of Then, as the punch continues to descend, at least two protruding cutting edges on the tip end surface of the punch that are inscribed in the workpiece start shearing the workpiece.

Here, during this shearing process, only the protruding cutting edge on the punch tip surface penetrates into the workpiece, and the other part of the punch tip surface is located some distance from the inner peripheral surface of the workpiece. Of course, plastic flow due to compression of the workpiece is effectively prevented;
The distributed stress acting on the punch tip surface due to the magnitude of the shear resistance of the workpiece is significantly reduced.

In this way, all the protruding cutting edges on the punch tip surface are completely penetrated into the workpiece.
In a preferred embodiment, the shearing of the workpiece is completed with sufficient precision, and the punch then ejects the sheared scrap from the punched hole in the workpiece and into the die hole.

Note that here, when the punch tip surface does not have protruding cutting edges at both ends that are spaced apart in the circumferential direction of the workpiece, in other words, when it has only two protruding cutting edges that are spaced apart in the axial direction of the workpiece. In this case, after the protruding cutting blades penetrate into the workpiece, shearing of the workpiece by the edge cutting blades spaced apart in the circumferential direction of the workpiece on the tip face of the punch begins, and those edge edges Shearing of the workpiece is completed when the cutting blade is sufficiently pushed into the workpiece.

Therefore, here, it is possible to perform drilling with sufficient accuracy on the workpiece under the action of the punch tip surface having a simple shape, so that the manufacturing cost of the punch and, by extension, the drilling die is significantly reduced. Chips and other damage caused by stress concentration on the punch tip surface can be sufficiently prevented. Moreover, the punch tip surface here effectively prevents the plastic flow of the workpiece and the action of distributed stress on the tip surface, so there is no risk of prying force acting on the punch or abrasion or welding to the punch side surface. Therefore, machining accuracy is maintained sufficiently over a long period of time, and the durability of the punch is increased to approximately 10 times that of conventional products.

In addition, since the workpiece is sheared by a concentrated load acting on the cutting edge at the tip of the punch, the power required at the same time is reduced. It is also sufficient to apply

(Example) This invention will be explained below based on illustrated examples.

FIG. 1 is a sectional view showing an embodiment of this invention, and FIG. 2 is a sectional view taken along the line - in FIG.

In the figure, reference numeral 1 indicates a thick ring-shaped workpiece, and the outer circumferential surface 1a of the workpiece 1 has a substantially spherical shape as a whole. In addition, the inner peripheral surface 1 of this work 1
b consists of a substantially spherical portion and a straight hole portion located adjacent to one side of the spherical portion and having a hole diameter larger than the maximum diameter of the spherical portion; In between, there is a protrusion 1c that greatly protrudes inward in the radial direction of the workpiece 1. Therefore, the thickness of the workpiece 1 changes greatly in its axial direction, particularly towards its inner circumferential side.

In addition, 2 in the figure shows a button die that makes surface contact with the almost spherical outer peripheral surface of the ring-shaped workpiece 1,
This button die 2 has a cutting edge 2a that corresponds to the contour of the required perforation portion of the workpiece 1, including the protrusion 1c.

Here, this button die 2 is raised by a wedge mechanism (not shown) to a ring-shaped workpiece 1 which is positioned and fixed by a nest 3 and a chuck device 4, so that the ring-shaped workpiece 1 and the outer circumferential surface of the workpiece are brought into contact with each other. By bringing about the contact, the workpiece 1 is supported in the radial direction when a punch, which will be described later, comes into contact with the workpiece 1 and cooperates with the punch. Here, the nest 3 acts to position the workpiece 1 at one end thereof in the axial and radial directions, and the chuck device 4 transports the workpiece 1 and positions it at a predetermined position in the nest 3. At the same time, it also functions to clamp.

Further, numeral 5 in the figure indicates a piercing punch placed inside the ring-shaped workpiece 1. As is clear from FIG. 3, the piercing punch 5 in this example has a projection on its tip surface 5a that simultaneously contacts the inner peripheral surface 1b of the workpiece 1 at both ends in the axial direction of the workpiece 1. In addition to the cutting blades 5b and 5c, the workpiece 1
It has protruding cutting edges 5d and 5e that simultaneously contact the inner circumferential surface 1b of the workpiece 1 at both ends in the circumferential direction,
These protruding cutting edges 5b, 5c, 5d, and 5e are made continuous with each other as shown in the figure.
Blade edge 5 corresponding to the outline of the required drilling part of the workpiece 1
form f. Here, it is preferable that the protrusion height of each of these protruding cutting edges 5b, 5c, 5d, and 5e is selected so that all of them contact the inner circumferential surface 1b of the workpiece 1 at the same time.

Therefore, the punch tip face 5a here has a recessed part 5g as shown in FIG. The 5g bottom wall does not come into contact with the workpiece 1 even during the shearing process on the workpiece 1.

Further, here, the blade edge 5f of the piercing punch 5 is positioned with a clearance of 0.4 to 0.5% of the workpiece plate thickness with respect to the blade edge 2a of the button die 2.

In this example, the piercing punch 5 as described above is inserted into the workpiece 1 as shown in FIG.
The punch retainer 6 is fixed with a bolt to a punch retainer 6 having a contour that does not interfere with the nest 3, and the punch retainer 6 and the piercing punch 5 are made movable in the vertical direction in the figure by a guide mechanism (not shown).

Here, the punch retainer 6 is driven up and down by a ram of a press machine or other driving means (not shown).

The operation of the hole-drilling die constructed in this way is explained in the fourth to sixth sections showing the relationship between the punch 5 and the workpiece in cross-section.
This will be explained below based on the figures.

Here, as shown in FIG. 1, a ring-shaped workpiece 1 is clamped at a predetermined position by a nest 3 and a chuck device 4, and a button die 2 is brought into surface contact with the outer peripheral surface of the workpiece 1. By lowering the piercing punch 5 together with the punch retainer 6, first, as shown in FIG.
5e, in the figure, the cutting blades 5b and 5c are brought into contact with the inner circumferential surface 1b of the workpiece 1 at the same time. In addition, according to a preferred example, in addition to the cutting edges 5b and 5c, the protruding cutting edges 5d and 5e also come into contact with the inner circumferential surface 1b at the same time.

And with the continued descent of the piercing punch 5,
The protruding cutting edges 5b, 5c penetrate into the workpiece, as shown in FIG. 5, and shear the workpiece 1 at the contour position of the required perforation portion of the workpiece 1.

Here, when shearing the workpiece 1 with the cutting blades 5b and 5c, the recessed portion 5g of the punch 5
Since the bottom wall of the workpiece 1 is reliably separated from the inner circumferential surface 1b of the workpiece 1 until the end of shearing of the workpiece 1, the recessed portion 5g prevents the movement from the thick part to the thin part of the workpiece 1. There is no risk of plastic flow occurring, and furthermore, external forces in the prying direction due to differences in shear resistance at respective shear points of the workpiece do not have a large effect on the punch 5.

Therefore, here, wear and welding phenomena do not occur on the side surface 5h of the punch 5 located on the thick-walled portion side, and therefore, the punch 5 can sufficiently maintain high machining accuracy. Moreover, the durability of the punch 5 is improved by about 10 times compared to the conventional technology.

In addition, the shearing of the workpiece 1 under the cooperation of the die 2 and the punch 5 is caused by each protruding cutting edge 5b of the punch 5,
5c is completely penetrated into the workpiece 1, as shown in FIG. Scrap 1d generated by shearing is discharged into the die hole through a punched hole 1e with excellent dimensional accuracy.

Therefore, here, the protruding cutting blades 5b and 5c are mainly used.
By shearing the workpiece under the action of This effectively prevents damage such as loss of 5. In addition, when shearing the workpiece 1, the inner peripheral surface of the workpiece 1 acts on the punch 5 with an external force in the prying direction, resulting in a decrease in processing accuracy and a decrease in the durability of the punch 5. Never.

Moreover, in this drilling type, a concentrated load acts on the protruding cutting edges 5b and 5c of the punch 5, so even a small-capacity press machine can perform the desired drilling process on the workpiece 1. .

(Effects of the invention) As described above, according to this invention, it is possible to obtain a highly durable drilling die that can maintain high machining accuracy over a long period of time while reducing costs. , it becomes possible to reduce the capacity of the press machine that brings about the operation of the punch.

[Brief explanation of drawings]

Figures 1 and 2 are sectional views showing an embodiment of this invention, Figure 3 is a diagram showing a piercing punch, and Figure 4 is a cross-sectional view showing an embodiment of this invention.
Figures 1 to 6 are operation process diagrams of the drilling dies. 1...Ring-shaped workpiece, 1a...Outer peripheral surface, 1b
...Inner peripheral surface, 1c...Protrusion, 2...Button die,
2a, 5f...blade edge, 5...piercing punch, 5a
... Tip surface, 5b, 5c, 5d, 5e ... Projection cutting blade, 6 ... Punch retainer.

Claims (1)

[Claims for Utility Model Registration] Consisting of a die 2 that makes surface contact with the outer peripheral surface of a thick ring-shaped workpiece 1, and a punch 5 that is disposed inside the workpiece and cooperates with the die, In a drilling die that performs a predetermined drilling process on the ring-shaped workpiece whose thickness changes, the tip surface 5a of the punch 5 is brought into contact with the inner peripheral surface 1b of the workpiece 1 at both ends thereof in the axial direction of the workpiece 1 at the same time. A drilling type provided with two protruding cutting blades 5b and 5c.