JP2001179498A - Isotropic pressure press device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the permanent set of backup members and damage by a plastic flow to the side of the inside face of a die even a press device is used under high pressure. SOLUTION: This device is an isotropic pressure press device in which a forming die 4 consisting of an elastic body is arranged in the inside of the die 3 and the compressive force in the axial direction of punches 5, 6 which are inserted into the die 3 is converted into the approximately isotropic compressive force by acting on the forming die 4 and which is provided with ring-shaped elastic backup members 10 between the punches 5, 6 and the forming die 4. Slopes 12 which face to the outward direction of a diameter and act so as to expand the backup members 10 in the outward direction of the diameter are formed in the edge parts of the punches 5, 6 which are opposed to the forming die 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an isostatic press used in the field of powder metallurgy, for example.

[0002]

2. Description of the Related Art Powder metallurgy, in which powder materials such as metals and ceramics are pressed and then sintered, is widely used in the production of mechanical parts, structural materials or electronic component materials. 2. Description of the Related Art An isostatic pressing device is known as one of devices for performing pressure molding. In this isotropic pressure press, for example, as described in JP-A-6-170598, a rubber mold is arranged inside a die (mold), and a process of powder or the like is performed in a cavity of the rubber mold. The material is filled, and the axial compression force of the punch inserted into the die is applied to the rubber mold to convert it into a substantially isotropic compression force and press the workpiece. .

[0003]

In this type of isotropic pressure press, the inner diameter of the die is enlarged by the pressure generated in the rubber mold due to the axial compression force of the punch.
This entails the disadvantage that the rubber mold plastically flows in the gap between the inner surface of the die and the punch caused by the enlargement, causing deformation and damage. For this reason, in the publication described above, a backup ring made of a material that is harder and more elastic than the rubber mold is provided between the punch and the rubber mold, and the die expands in the radial direction of the backup ring due to the compressive force of the punch. The gap between the rubber mold and the punch is sealed from the rubber mold, thereby preventing the plastic flow of the rubber mold.

Further, by chamfering the edge portion of the backup ring facing the punch, the edge is prevented from being caught in the gap, thereby preventing the punch plate from being moved while maintaining the durability of the backup plate. Was also possible. However,
The above backup ring has a structure that receives the axial pressure from the punch and the rubber mold by a surface perpendicular to this direction.Therefore, although some effects can be obtained when used under low pressure, chamfering is performed under high pressure. The permanent deformation (plastic deformation) of the backup ring itself flatly irrespective of the presence or absence of the edge, and the phenomenon that the edge is bitten into the gap cannot be completely avoided.

[0005] Further, when the inner diameter of the die is large, the absolute value of the expansion amount becomes large. Therefore, the expansion of the backup ring alone cannot follow the expansion of the inner diameter of the die, and the sealing effect is impaired. Was. The present invention has been made in view of such circumstances, and by expanding the backup member in the radially outward direction during pressurization,
It is an object of the present invention to improve sealing performance, prevent biting, damage, and permanent deformation due to plastic flow of a backup member even when used under high pressure, and improve durability.

[0006]

The present invention employs the following technical means to achieve the above object. That is, according to the present invention, a molding die made of an elastic material is arranged inside a die, and the axial compression force of a punch inserted into the die is converted into a substantially isotropic compression force by acting on the molding die. An isotropic pressure press device comprising a ring-shaped backup member having elasticity between the punch and the molding die, wherein an edge portion of the molding die facing the punch, and / or Alternatively, the backup member is attached to an edge portion of the punch opposite to the molding die, and an inclined surface facing in a radial direction that acts to expand the backup member in a radial direction is formed. It is characterized by the following.

According to this, when an axial compressive force is applied by the punch, a pressure having a radially outward component acts on the backup member from the inclined surface, and the backup member follows the expansion of the inner diameter of the die. Spread in the direction. And, by this expansion, the gap between the die and the punch is reliably sealed, and plastic flow of the mold is prevented. Further, by expanding the backup member itself in the radial direction, it is possible to prevent the backup member from being permanently deformed flat and bitten between the die and the punch. The backup member is preferably formed in a substantially triangular cross section having three surfaces, that is, surfaces that come into surface contact with the inclined surface and the inner surface of the die, and a surface that faces the punch or the mold. May be formed in a substantially triangular cross section, or a plurality of members may be formed in a substantially triangular cross section by layering.

The backup member is preferably formed to have a higher hardness than a molding die, whereby it is possible to reliably prevent the backup member itself from plastically flowing into the gap between the inner surface of the die and the punch. In the case where the backup member is formed with a higher hardness than the molding die, and when the hardness difference between the backup member and the molding die is large, the molding die expands in the radially outward direction faster than the backup member is expanded. Therefore, there is a risk that the mold will plastically flow in the gap between the backup member and the inner surface of the die.

Therefore, in the present invention, when the backup member is provided on the punch side, the hardness between the backup member and the molding die is higher than that of the molding die and higher than that of the backup member. A second backup member made of a material having low elasticity is interposed. Thereby, the difference in hardness between the mold and the second backup member, and the difference in hardness between the second backup member and the backup member are reduced, and the mold may plastically flow between the second backup member and the die inner surface, The second backup member can be prevented from plastically flowing between the backup member and the inner surface of the die.

When a backup member is provided on both the punch side and the molding die side, it is preferable that the hardness of the backup member on the molding die side be low and the hardness of the backup member on the punch side be high. Thus, similarly to the above, the hardness of the backup member is reduced on the mold side (the difference in hardness from the mold) is reduced, and the mold is prevented from flowing plastically between the backup member and the inner surface of the die. ,
Further, by increasing the hardness of the backup member on the punch side, it is possible to prevent the backup member from biting into the gap between the inner surface of the die and the punch.

Further, as described above, when the backup member is formed in a triangular cross-section by laminating a plurality of members in layers, the hardness of the member on the molding die side is low.
It is preferable that the hardness of the member on the punch side is increased. This reduces the difference in hardness between the mold and the backup member, and increases the hardness of the backup member on the punch side while preventing the mold from plastically flowing between the backup member and the inner surface of the die. Thus, the backup member can be easily prevented from biting into the gap between the inner surface of the die and the punch.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a main part of an isotropic pressure press apparatus 1 according to the present invention, in which a soft elastic material such as rubber is provided inside a die (mold) 3 having a vertical through hole 2 in the center. A molding die 4 made of a material is arranged, and an upper punch 5 and a lower punch 6 are inserted from upper and lower openings of the die 3 to sandwich the molding die 4, and both or one of the upper and lower punches 5 and 6 are inserted. By being pushed into the die 3, a compressive force in the axial direction (vertical direction) acts on the mold 4.

An object to be processed 7 such as a powder raw material is inserted into the molding die 4.
Is converted into a substantially isotropic compression force by the molding die 4 so as to press-mold the workpiece 7. A ring-shaped backup member 10 is provided at an edge of a surface of the upper and lower punches 5 and 6 facing the mold 4. Specifically, the edge portion is chamfered in an oblique direction so that an inclined surface 12 facing in a radially outward direction is formed on the entire circumference,
A space 11 having a triangular cross section is formed between the inclined surface 12 and the inner surface of the die 3 and the upper and lower surfaces of the mold 4.
1, a ring-shaped backup member 10 is inserted.

The backup member 10 includes a punch 5,
When the inner diameter of the die 3 is increased by the pressure generated in the molding die 4 by the axial compression force from the
The molding die 4 is sealed so as not to plastically flow into a gap formed between the molding die 4 and the inclined surface 12 made of a synthetic resin, metal, rubber, or the like having a higher hardness than the molding die 4 and having elasticity. The inner surface of the die 3 and the upper and lower surfaces of the molding die 4 are formed in a substantially triangular cross section having three surfaces in surface contact. The operation of the backup member 10 provided between the upper punch 5 and the mold 4 will be described below with reference to FIG.

When an axial compression force is applied to the molding die 4 by the upper punch 5 from the state shown in FIG. 2A where the compression force from the upper punch 5 is not applied, as shown in FIG. 4
, The inner diameter of the die 3 increases, and the gap t between the inner surface of the die 3 and the upper punch 5 increases. At this time, the backup member 10 receives an upward pressure P1 from the mold 4 and receives a pressure P2 having downward and radial components from the inclined surface 12, whereby
The backup member 10 is expanded outward (see arrow B) following the expansion of the inner diameter of the die 3 while moving upward relative to the upper punch 5 along the inclined surface 12. The gap t is reliably sealed from the mold 4 by the expansion.

Therefore, biting, damage, and the like caused by the plastic flow of the molding die 4 into the gap t can be prevented, and the durability of the molding die 4 is improved. The inclined surface 12
Since the pressure P2 applied to the backup member 10 from, not only the axial component, but also a part of the pressure P2 is dispersed in the radially outward force, and the backup member 10 expands in the radially outward direction. As a result, the pressure can escape from the pressure in the axial direction, so that the sectional shape hardly changes even when used under high pressure. When the pressure is released, the state returns to the state shown in FIG. ing.

Accordingly, the backup member 10 hardly plastically flows between the inner surface of the die 3 and the upper punch 5 and bites into the flat member, and is hardly permanently deformed flat, so that the durability is improved. Has become. by the way,
In the above embodiment, if the difference in hardness between the backup member 10 and the molding die 4 is large, the molding die 4 expands in the radial direction faster than the backup member 10 expands, so that the backup member 10 and the die 3 Plastic flow may occur in the gap with the inner surface, causing deformation and damage.

Therefore, in FIG. 3 showing a second embodiment of the present invention, between the backup member (first backup member) 10 and the mold 4, the first member is harder than the mold 4, And a second backup member 13 which is softer than the backup member 10 and is made of a material having elasticity such as synthetic resin, metal, or rubber. 13
Hardness difference between the second backup member 13 and the mold 4
Is smaller than the hardness difference between the molding die 4 and the first backup member 10, the molding die 4 plastically flows into the gap between the second backup member 13 and the inner surface of the die 3, or the second backup member 13 is the inner surface of the die 3 and the first
This prevents plastic flow and biting into the gap with the backup member 10.

In the present embodiment, a concave portion 14 having an L-shaped bottom is formed in the circumferential direction at the edge of the upper surface of the molding die 4 facing the upper punch 5, and this concave portion 14 and the inner surface of the die 3 and A ring-shaped second backup member 13 is formed in a space 15 formed between the first backup member 10 and the lower surface thereof.
It is assumed that it was charged. However, the second backup member 13 may be formed in a plate shape so as to cover the entire upper surface of the mold 4. FIG. 4 shows a third embodiment of the present invention.

In the present embodiment, an oblique chamfer is applied to the edge of the upper surface of the molding die 4 facing the upper punch 5, thereby forming an inclined surface 12 facing outward. The backup member 10 includes an inclined surface 12,
It has a triangular cross section having three surfaces that are in surface contact with the inner surface of the die 3 and the lower surface of the upper punch 5, and is inserted into a space 11 formed between the surfaces. And FIG.
As shown in (b), the backup member 10 receives the pressure P1 in the up-down direction from the upper punch 5 and receives the pressure P2 having the upward and radial components from the inclined surface 12 so that the die 3 It is urged to expand in the radially outward direction following the increase in the inner diameter.

Therefore, the gap t is reliably sealed by the backup member 10 and the
Of the backup member 10 is prevented.
Is prevented from being permanently deformed and biting into the gap t, thereby improving durability. FIG. 5 shows a fourth embodiment of the present invention. The present embodiment is a combination of the first embodiment shown in FIGS. 1 and 2 and the third embodiment shown in FIG. 4, and the upper punch 5 and the forming die 4 have opposite edge portions. , An inclined surface 1 which faces outward in a radial direction by chamfering each in an oblique direction.
2 ′, 12 ″ are formed, and backup members 10 ′, 10 ″ having a triangular cross section are inserted into the cavities 11 ′, 11 ″ formed by the respective inclined surfaces 12 ′, 12 ″ and the inner surface of the die 3. It has become something.

Then, each backup member 10 ', 1
0 "is urged to expand in the radial direction by receiving the pressures P2 ', P2" having the radial components from the inclined surfaces 12', 12 ". In the fourth embodiment, it is possible to form the backup members 10 ′ and 10 ″ with the same hardness and material, but the backup member on the punch 5 side can be used. Preferably, the hardness of 10 ′ is higher than that of the backup member 10 ″ on the side of the molding die 4, so that the backup member 10 ″ on the side of the molding die 4 becomes the second backup member shown in the second embodiment. 13 as well.

That is, in this case, the difference in hardness between the backup member 10 ″ on the forming die 4 side and the forming die 4 and the difference in hardness between the backup members 10 ′ and 10 ″ are determined by the difference between the forming member 4 and the punch 5 side. Since the hardness difference is smaller than the backup member 10 ′, the molding die 4 plastically flows into the gap between the backup member 10 ″ and the inner surface of the die 3. It is possible to prevent plastic flow and biting in the gap between the member 10 'and the inner surface of the die 3. Further, since the hardness of the backup member 10 ′ on the punch 5 side is increased, it is possible to prevent the backup member 10 ′ from biting into the gap t between the inner surface of the die 3 and the punch 5.

FIG. 6 shows a fifth embodiment of the present invention. In the present embodiment, the backup member 10 is formed in a plurality of layers, and the surface that comes into surface contact with the inclined surface 12 formed on the molding die 4 is the base, and the top is substantially parallel to the inclined surface 12. First member 10 having a trapezoidal cross section
A, and a second member 10B having a triangular cross-section so as to make surface contact with the top side of the first member 10A. As a whole, the inclined surface 12, the inner surface of the die 3, and the lower surface of the upper punch 5 It has a triangular cross-section so as to make surface contact. Therefore, the backup member 10 of the present embodiment is
Has a plurality of layers in a direction perpendicular to the vertical direction.

The first member 10A has a higher hardness than the molding die 4, and the second member 10B has a higher hardness than the first member 10A. According to the present embodiment, the pressure P2 from the inclined surface 12 is reduced by the backup member 10.
4 has an effect similar to that of the third embodiment shown in FIG. 4 except that the backup member 10 has a hardness at least at a portion facing the die 3. The configuration is such that the mold 4 side is lower and the upper punch 5 side is higher, so that the die 3
The backup member 10 is less likely to bite into the gap t with the inner surface, and the backup member 10
The molding die 4 can be prevented from flowing plastically between the mold 3 and the inner surface of the die 3.

The backup member 10 can be provided on the punch 5 side.
The members 10A and 10B of each layer may be arranged so that the hardness on the molding die 4 side is low and the hardness on the punch 5 side is high.
FIG. 7 shows a sixth embodiment of the present invention. In this embodiment, the backup member 10 provided on the punch 5 side is used.
Are formed in a plurality of layers, a first member 10A having a trapezoidal cross section having a bottom surface in contact with the upper surface of the molding die 4 and a top surface in parallel with the first surface, and the first member 10
A has a second member 10B formed in a triangular cross section so as to make surface contact with the top side, and has three surfaces that make surface contact with the inclined surface 12, the inner surface of the die 3, and the upper surface of the mold 4 as a whole. It has a triangular cross section. Therefore, the backup member 10 of the present embodiment has a plurality of layers in the axial direction.

The first member 10A has a higher hardness than the molding die 4, and the second member 10B has a higher hardness than the first member. In the present embodiment, the pressure P2 from the inclined surface 12 is
1 and 2 has the same effect as the first embodiment shown in FIGS. 1 and 2 in that the
As in the fifth embodiment, the hardness of the backup member 10 is formed so that the hardness of the backup member 10 is lower and the hardness of the upper punch 5 is higher.
The plastic flow of the mold 4 is reduced, and the hardness of the mold 4 is reduced to prevent the mold 4 from flowing plastically between the backup member 10 and the inner surface of the die 3.

The backup member 10 can be provided on the molding die 4 side. Also in this case, the members 10A of each layer are formed so that the hardness on the molding die 4 side is low and the hardness on the punch 5 side is high. , 10B may be arranged. In the fifth and sixth embodiments, the backup member 1
0 is composed of two layers, but may be composed of three or more layers.
B may be integrally formed by being fixed, or may be in a state of being detachably contacted.

FIG. 8 shows a seventh embodiment of the present invention. This embodiment is a combination of the first embodiment shown in FIG. 2 and the fifth embodiment shown in FIG. Further, the backup member 10 'on the upper punch 5 side is replaced with the second backup member 10 "on the molding die 4 side.
It is formed with higher hardness than the member 10B.
In the present embodiment, the same operation and effects as those of the first and fifth embodiments are obtained, and further, the hardness of the molding die 4 side is low and the hardness of the punch side is high as a whole for each of the backup members 10 ′ and 10 ″. As a result, the backup members 10 ′, 10 ″ and the mold 4 are prevented from plastically flowing into the gap between the die 3 and the inner surface of the die 3.

The backup member 10 'on the upper punch side 5 of this embodiment may be formed in a plurality of layers in the axial direction as in the sixth embodiment shown in FIG. 7, or in a plurality of layers in a direction perpendicular to the inclined surface 12'. May be configured. 3 to 9, the backup member 1 provided between the upper punch 5 and the mold 4.
0, but between the lower punch 6 and the forming die 4, similar backup members 10, 10 ', 1
0 "may be provided, and in this case, the same configuration and operation and effect are obtained except that the relationship in the vertical direction is reversed.

In the present invention, a backup member 10 may be provided either between the molding die 4 and the upper punch 5 or between the molding die 4 and the lower punch 6.
When the lower punch 6 or the upper punch 5 is formed integrally with the die 3 or the like, it is not necessary to particularly provide a backup ring at that portion. In addition, the inclined surface 1 of each of the above embodiments.
The ends of 2, 12 ', 12 "may be further chamfered in a flat or round shape, and the inclined surfaces 12, 12', 12 'themselves may be formed in an arc shape (arc surface). Further, the corners of the backup members 10, 10 ', 10 "may be chamfered.

[0032]

As described above in detail, according to the present invention, a radially-facing inclined surface that acts to radially expand the backup member at the edge of the punch and / or the mold. Since the backup member is formed, the sealing performance is improved by expanding the backup member, and the backup member is flat and permanently deformed even when used under high pressure,
It is possible to prevent the plastic fluid from flowing into the gap and to bite the gap, thereby improving the durability.

[Brief description of the drawings]

FIG. 1 is a front sectional view showing a main part of an isotropic pressure press device according to the present invention.

FIG. 2A is an enlarged sectional view of a portion A in FIG. 1, and FIG. 2B is an enlarged sectional view of the portion A when a compressive force of a punch acts.

FIG. 3 is an enlarged cross-sectional view corresponding to FIG. 2 of an isotropic pressure press device according to a second embodiment of the present invention.

FIG. 4 is an enlarged cross-sectional view corresponding to FIG. 2 of an isotropic pressure press device according to a third embodiment of the present invention.

FIG. 5 is an enlarged sectional view corresponding to FIG. 2 of an isotropic pressure press device according to a fourth embodiment of the present invention.

FIG. 6 is an enlarged sectional view corresponding to FIG. 2 of an isotropic pressure press device according to a fifth embodiment of the present invention.

FIG. 7 is an enlarged sectional view corresponding to FIG. 2 of an isotropic pressure press device according to a sixth embodiment of the present invention.

FIG. 8 is an enlarged sectional view corresponding to FIG. 2 of an isotropic press machine according to a seventh embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Isotropic press machine 3 Die 4 Mold 5 Upper punch 6 Lower punch 10 Backup member 12 Inclined surface 13 Second backup member

Claims (7)

[Claims] 1. A molding die made of an elastic material is arranged inside a die, and the axial compression force of a punch inserted into the die acts on the molding die to convert it into a substantially isotropic compression force. An isotropic pressure press device comprising a ring-shaped backup member having elasticity between the punch and the molding die, wherein an edge portion of the molding die facing the punch, and / or
Or, at the edge of the punch facing the mold,
An isotropic pressure press device, wherein the backup member is mounted and has a radially outwardly inclined surface which acts to expand the backup member in a radially outward direction. 2. The backup member includes the inclined surface,
The isotropic pressure press device according to claim 1, wherein the pressurizing device is formed in a substantially triangular cross section having three surfaces, each of which is in surface contact with a die inner surface and a surface facing a punch or a mold. . 3. The isostatic pressing apparatus according to claim 2, wherein the backup member is formed in a substantially triangular cross section by laminating a plurality of members in layers. 4. The backup member according to claim 1, wherein the backup member has a higher hardness than a molding die.
3. The isotropic pressure press according to any one of 3. 5. In a case where the backup member is provided on the punch side, elasticity having a higher hardness than the molding die and a lower hardness than the backup member is provided between the backup member and the molding die. The isotropic pressure press device according to claim 4, wherein a second backup member made of a material having the same is interposed. 6. When the backup member is provided on the punch side and the molding die side, the hardness of the backup member on the molding die side is low and the hardness of the backup member on the punch side is high. The isotropic press machine according to claim 4, characterized in that: 7. The backup member is formed so as to have a higher hardness than a molding die, and has three surfaces of each of the inclined surface, the surface in contact with the inner surface of the die, and the surface facing the punch or the molding die. 2. A cross-section having a substantially triangular cross-section having a lower hardness on the mold side and a higher hardness on the punch side by laminating a plurality of members having different hardnesses in layers. Isotropic press machine.