JPH0694056B2 - Segment type mold and its manufacturing method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a segmented mold used in a multiple interference fit mold and the like, and a manufacturing method thereof.

[Conventional technology]

Generally, a die for plastic working such as a die for cold forging is required to have a high allowable working pressure, that is, a high allowable pressure, because a very high pressure acts during the plastic working.

FIG. 12 shows a part of a multiple interference fitting mold for forging a deformed shape.This multiple interference fitting mold clamps a die insert 13 in which a square die hole 11 is formed. It is configured by being fitted into the hole portion 17 of the cylindrical body 15.

In such a multiple interference fitting mold, the die insert 13
By preloading from the outside with the tightening force of the tightening cylinder 15, the surface stress of the die hole 11 is kept on the compression side, and the stress of the die hole 11 is pulled by the high pressure applied in the die hole 11 during processing. To prevent the die insert 13 from exceeding the yield stress and preventing the die from breaking, and thus increasing the allowable internal pressure in the die hole 11 compared to a single die. It is possible.

However, as shown in the figure, when the shape of the die hole 11 is an irregular shape, a large amount of stress is concentrated on each corner portion 19, which easily causes cracks in the corner portion 19 and shortens the mold life. There is a problem.

In order to solve such a problem, a segment mold as shown in FIG. 13 is used.

This segmented mold is configured by dividing the die insert 21 into four segments 23, and each segment 23 forms one side of a square die hole 25.

In such a segment-type mold, since the corner portion 27 of the die hole 25 is formed by the contact surface of the segment 23, stress is relatively less concentrated on the corner portion 27, and the multiple holes shown in FIG. The mold life can be extended as compared with the interference fitting mold.

[Problems to be solved by the invention]

However, in such a conventional segment mold, as shown in FIG. 14, since each segment 23 is formed by an arc having a radius r and an angle θ, the radius r and the angle θ
There is a problem that it is very difficult to accurately process.

That is, in such a segment type die, if the accuracy of the radius r and the angle θ is low, abnormal stress is generated in the corner portion 27 of the die hole 25, and the die life is shortened due to chipping or the like. .

[Object of the Invention]

An object of the present invention is to solve the above problems and to provide a segmented mold and a method of manufacturing the same that can easily perform highly accurate processing.

[Means for solving problems]

The segment type mold according to the present invention is such that a die insert having a die hole having a plurality of corners is fitted into a hole of a tightening cylinder, and the die insert is composed of a plurality of segments. In the segment type mold
At least one of the surfaces connecting the corners of the die hole is formed by a notched surface of a cylindrical segment embedded in the die insert.

In addition, the method for manufacturing a segmented mold of the present invention, after forming a circular embedded hole in the die insert so that two corners of the die hole to be formed in the die insert are located on the inner peripheral surface, A columnar segment is embedded in the embedded hole, the die insert in which the columnar segment is embedded is fitted into the hole of the tightening cylinder, and then a die hole is formed in the die insert.

[Operation of the invention]

In the segmented mold of the present invention, at least one of the surfaces connecting the corners of the die hole and the corners is formed by the notched surface of the cylindrical segment embedded in the die insert, and a high pressure is applied to the notched surface of the cylindrical segment. Will work.

Further, in the method for manufacturing a segmented mold of the present invention, a circular embedded hole is formed in the die insert so that two corners of the die hole to be formed in the die insert are located on the inner peripheral surface. After that, a columnar segment is embedded in the embedded hole, the die insert in which the columnar segment is embedded is fitted into the hole of the tightening cylinder, and then a die hole is formed in the die insert.

Example of Invention

 Hereinafter, details of the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of the segmented mold of the present invention. In the drawing, reference numeral 31 indicates a cylindrical die insert.

The die insert 31 is formed with a rectangular parallelepiped die hole 33 having four corners. The die insert 31 is fitted in the hole 37 of the annular tightening cylinder 35.

Thus, in this embodiment, the die insert 31 is composed of the main body segment 39 and the columnar segment 41.

That is, in the body segment 39, at regular intervals,
A pair of circular embedding holes 43 are formed, and a columnar segment 41 is inserted into these embedding holes 43.

Then, of the four surfaces that connect the corner portions 45 of the die hole 33, the two surfaces with the smaller width are the cylindrical segments embedded in the die insert 31.
It is formed by the notch surface 47 of 41.

The segment type mold configured as described above is manufactured by the method for manufacturing a segment type mold of the present invention as described below.

That is, in the method of the present invention, first, as shown in FIG. 2, the main body is made so that the two corner portions 45 of the die hole 33 to be formed in the main body segment 39 are located on the inner peripheral surface of the embedding hole 43. A circular buried hole 43 is formed in the segment 39 with high accuracy.

After that, as shown in FIG. 3, the columnar segment 41 is embedded in the embedding hole 43. This embedding is performed, for example, by processing the outer diameter of the cylindrical segment 41 to be larger than the inner diameter of the embedding hole 43 by about 5 μm and then press-fitting it.

Thereafter, as shown in FIG. 4, the main body segment 39 in which the columnar segment 41 is embedded is fitted into the hole portion 37 of the tightening tubular body 35. This fitting is performed by processing the outer diameter of the main body segment 39 to be slightly larger than the inner diameter of the tightening tubular body 35 and then shrink fitting.

Thereafter, as shown in FIG. 1, the die hole 33 is formed in the main body segment 39. The die hole 33 is formed, for example, by
It is formed by electric discharge machining, and the corner portion 45 of the die hole 33 is formed so as to be located on the outer periphery of the cylindrical segment 41.

Then, in the segment type mold configured as described above, two of the surfaces connecting the corner portions 45 of the die hole 33 and the corner portion 45 are notched surfaces of the cylindrical segment 41 embedded in the main body segment 39. Since it is formed by the method described above, it can be processed using the method for manufacturing a segmented mold of the present invention, and a segmented mold having extremely high accuracy is obtained.

That is, in the segment type mold and the manufacturing method thereof of the present invention, unlike the conventional segment type mold, each segment is not formed by an arc having a radius r and an angle θ, and has a cylindrical main body segment 39 and a cylinder. Since it is composed of the segments 41, it is possible to perform highly accurate processing, which improves the accuracy of the die insert 31, eliminates chipping and the like, and can significantly improve the life of the mold as compared with the conventional case.

Further, since the processing is easy, the number of processing steps can be reduced, and the cost of the segment mold can be reduced.

FIG. 5 shows a second embodiment of the segment mold of the present invention. In this embodiment, a rotation stopper for preventing the rotation of the columnar segment 41 straddling the columnar segment 41 and the main body segment 39 is shown. The pin 51 is buried. The detent pin 51 is embedded by being press-fitted into a pin hole formed by electrical discharge machining, for example.

In such a segment type mold, since the rotation of the columnar segment 41 is surely prevented, it is possible to reliably maintain the shape accuracy of the die insert 31.

FIG. 6 shows a third embodiment of the segment mold of the present invention. In this embodiment, a part of the outer peripheral surface of the columnar segment 53 is in direct contact with the tightening cylinder 35.

Such a segment type mold is constructed by embedding a columnar segment 53 in a main body segment 55 as shown in FIG. 3 and then cutting the outer periphery of the main body segment 55 into a circular shape as shown in FIG. A part 57 of the outer side portion of the cylindrical segment 53 is cut at the same time, and the die insert 59 thus obtained is shrink-fitted to the tightening tubular body 35 as shown in FIG. It can be easily manufactured by forming the die hole 33 shown in the figure.

The segment-type mold constructed as described above can also obtain substantially the same effect as that of the embodiment shown in FIG. 1, but in this embodiment, the columnar segment 53 is the fastening cylinder 35.
Since it directly contacts and is tightened, it is possible to reliably prevent the rotation of the columnar segment 53 without using a rotation stop pin or the like.

FIG. 9 shows a fourth embodiment of the segmented mold of the present invention. In this embodiment, the die hole 61 has a hexagonal shape, and the surfaces not adjacent to each other are notched surfaces of the cylindrical segment 63. It is formed by 65.

Such a segmented mold is manufactured in substantially the same manner as the first embodiment shown in FIG.

Also in the segment type die constructed as described above, it is possible to obtain substantially the same effect as that of the first embodiment shown in FIG.

FIG. 10 shows a fifth embodiment of the segment mold of the present invention. In this embodiment, the die hole 61 has a hexagonal shape, and the surfaces not adjacent to each other are notched surfaces of the cylindrical segment 67. Further, a part of the outer peripheral surface of the columnar segment 67 is in direct contact with the tightening tubular body 35.

Such a segment type mold is manufactured in substantially the same manner as the third embodiment shown in FIG.

The segment-type mold constructed as described above can also obtain substantially the same effect as that of the third embodiment shown in FIG.

In the embodiment described above, an example in which the present invention is applied to the die holes 33 and 61 in which the corners are linearly formed between the corners has been described, but the present invention is limited to such embodiments. Instead of this, as shown in FIG. 11, for example, a convex curved surface 69 or a concave curved surface 71 may be formed between the corners.

〔The invention's effect〕

As described above, in the segment mold of the present invention, since at least one of the surfaces connecting the corners of the die hole and the corners is formed by the notched surface of the cylindrical segment embedded in the die insert, the accuracy is high. The mold can be easily obtained.

In the method for manufacturing a segmented mold of the present invention, after the embedded holes are formed in the die insert so that the two corners of the die hole to be formed in the die insert are located on the inner peripheral surface, A cylindrical segment is embedded in this embedded hole, the die insert in which this cylindrical segment is embedded is inserted into the hole of the tightening cylinder, and after this, a die hole is formed in the die insert, so highly accurate machining Has the advantage that it can be performed easily.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of a segment mold of the present invention, FIG. 2 is a perspective view showing a state in which a buried hole is formed in a main body segment in the first embodiment, and FIG. FIG. 4 is a perspective view showing a state in which a cylindrical segment is embedded in an embedding hole of a main body segment in the embodiment, FIG. 4 is a perspective view showing a state in which the main body segment is inserted into the tightening cylinder in the first embodiment, and FIG. FIG. 6 is a perspective view showing a second embodiment of the segment mold of the present invention, and FIG. 6 is a third view of the segment mold of the present invention.
FIG. 7 is a perspective view showing an embodiment, FIG. 7 is a perspective view showing a state in which the outer periphery of the main body segment is cut in the third embodiment, and FIG. 8 is a state in which the main body segment is fitted in the tightening cylinder body in the third embodiment. FIG. 9 is a perspective view showing a fourth embodiment of the segmented mold of the present invention, FIG. 10 is a perspective view showing a fifth embodiment of the segmented mold of the present invention, and FIG. Is a perspective view showing another embodiment of the segmented mold of the present invention,
Figures and 13 are perspective views showing a conventional mold, and Figure 14 is a perspective view.
It is a perspective view which shows the segment of the metal mold | die of FIG. 31 …… die insert, 33 …… die hole, 35 …… tightening cylinder, 37 …… hole, 39 …… main body segment, 41 …… cylindrical segment, 43 …… buried hole, 45 …… corner, 47 …… Notched surface.

Claims (5)

[Claims] 1. A die insert (31) in which a die hole (33) having a plurality of corners (45) is formed is inserted into a hole (37) of a tightening cylinder (35) and at the same time, In a segmented mold comprising a die insert (31) composed of a plurality of segments, at least one of the surfaces connecting the corners (45) of the die hole to the die insert (31 ), The notch surface (4
Segment type mold characterized by being formed by 7). 2. The segment type mold according to claim 1, wherein the die hole (33) has a polygonal shape, and the surfaces not adjacent to each other are formed by the notched surfaces of the cylindrical segment (41). . 3. The segmented mold according to claim 1, wherein the notch surface (47) is a concave curved surface or a convex curved surface. 4. A circular embedded hole (43) is formed in the die insert (31) so that two corners of the die hole (33) to be formed in the die insert (31) are located on the inner peripheral surface. After forming, the columnar segment (41) is embedded in the embedding hole (43), and the die insert (31) in which the columnar segment (41) is embedded is inserted in the hole (37) of the tightening cylinder (35). A method for manufacturing a segmented mold, which comprises fitting and then forming a die hole (33) in the die insert (31). 5. The method of manufacturing a segmented mold according to claim 4, wherein the die hole (33) is formed by electric discharge machining.