JPH0534871Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) This invention accommodates various powders such as cemented carbide and ceramic powders in a rubber mold, and uses cold isostatic pressure to mold them along the rubber mold. This invention relates to improvements in rubber molds used in cold isostatic presses for compression molding.

(Prior Art) This type of conventional technology is shown in FIG. 4.

In the figure, the hydrostatic press has a cylindrical molded container 1 with both upper and lower ends open, and an upper lid 2 and a lower outer lid 3 are attached to the upper and lower open ends of the container 1, respectively. The upper lid 2 is provided with a pressure medium supply port. A lower inner cover 5 attached to a pedestal 4 is removably fitted into the lower outer cover 3.
Inside the molding container 1, a rubber mold consisting of a cylindrical internal pressurized rubber mold 9 and a lid-shaped internal pressurized rubber mold 8 that closes the upper opening is inserted through an external pressurized rubber mold 7 whose lower end is open. , is placed and set across the lower outer cover 3 and lower inner cover 5. In the case of the example shown, rubber molds 8 and 9 are used to compression mold the powder to be molded into a ball shape.
A plurality of rubber molds 10 having further powder loading chambers 11 are incorporated therein. After assembling as shown in the figure, the upper lid 2 and the pedestal 4 are held between the movable press frame 6 to bear the axial load generated during pressure molding, and the pressure medium is supplied into the loading chamber 11. The loaded powder to be molded is put into a rubber mold 8,
9 is compression-molded into a ball-shaped product through isostatic pressing from the circumferential and vertical upper portions.

(Problems to be solved by the invention) The conventional rubber mold has the following problems.

That is, as shown in FIGS. 5 and 6, the internal pressurized rubber molds 8 and 9, including the external pressurized rubber mold 7, are integrally formed with the molded container 1 on the lower end (vertical direction) side of the rubber mold. It is supported by the lower outer cover 3 and lower inner cover 5 that are assembled, and the ultra-high pressure applied by the pressure medium is concentrated under isostatic pressure downward in the radial and vertical directions of the rubber mold, so when pressurizing, the Partial deformation occurs as shown in Figure 6.

In order to obtain a ball-shaped product in the rubber molds 8 and 9 as shown in the figure, a plurality of molding rubber molds 10 are combined to form a powder loading chamber 11, and the powder to be molded 17 is compression-molded. In such a case, as shown in FIG. 6, the central part of the rubber mold 8 in particular is greatly bent in the direction of the load, so the molded shape of the loaded powder 17 is greatly distorted into a flattened shape, resulting in poor shape. There was a problem that caused this.

Therefore, an object of the present invention is to provide a rubber mold for cold isostatic press that solves the above problems.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention takes the following measures. That is, the feature of the present invention is that the upper and lower openings of the cylindrical molded container of the cold isostatic press are covered with upper and lower lids, thereby forming a pressurized space inside the molded container. , a rubber mold 2 in which a cylindrical convex portion protruding into the space is formed on the upper surface of the lower lid, and a lower end opening is externally fitted into the convex portion;
8, the rubber mold has a cylindrical body made of rubber whose lower end opening fits into the front part, and a top part that covers an upper part of the body part, and the top part is made of rubber. It has a composite structure of a plate and a high-rigidity plate that has higher rigidity than the rubber of the body.

(Function) According to the present invention, the rubber mold containing the powder to be molded is set in a pressure vessel, and isostatic pressure is applied to the body and top of the rubber mold, and the molded material inside is heated. The powder is compression molded.

During the isostatic pressurization, the rubber mold does not deform because its lower part is fitted onto the convex portion of the lower lid.

Therefore, the isostatic pressing force acts on the rubber mold in the radial direction and vertically downward direction of the rubber mold. At this time,
Since the top of the rubber mold is constructed with high rigidity, the top does not bend significantly in the axial direction when subjected to a high pressure axial load applied from vertically above, and the powder to be molded inside is uniformly applied. Pressure molding can be performed to obtain an accurate molded shape.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

In FIG. 1, an example of a dry isostatic press is shown, and a cylindrical molded container 21 with openings at both upper and lower ends
An upper lid 22 and a lower outer lid 23 are provided at the upper and lower opening ends of the
The upper lid 22 is provided with a pressure medium supply port, and a lower inner lid 25 attached to a pedestal 24 is removably inserted into the lower outer lid 23.

The upper lid 22 and the pedestal 24 are held between a movable press frame 26 and bear the axial load generated within the molded container 21.

Inside the molding container 21, an external pressurized rubber mold 27, an internal pressurized rubber mold 28, and a molded rubber mold 2 are placed and set across the lower outer lid 23 and the lower inner lid 25.
9 is stored.

The external pressure rubber mold 27 is formed into a cylindrical shape with an open lower end and a closed upper end, and the lower end opening fits into the lower outer lid 23 .

The internal rubber mold 28 is connected to the external pressurized rubber mold 2.
7, and consists of a cylindrical body part 30 with openings at the upper and lower ends, and a top part 31 that covers the upper end opening of the body part 30.

The lower end opening of this body 30 is connected to the lower inner lid 25.
The lower end surface of the body portion 30 is placed on the lower outer lid 23.

Therefore, the upper part of the lower inner lid 25 is formed by a rubber mold 28.
A convex portion is formed to fit inside the opening at the lower end.

The top portion 31 is a highly rigid plate 31 such as a steel plate.
It has a composite structure of a and a rubber plate 31b. The high rigidity plate 31a is formed into a disk shape with a convex cross section, and the rubber plate 31b is formed into a disk shape with a concave cross section.
a and 31b are integrally bonded together in a fitting manner, but the fitting structure is not limited to that shown in the figure.

Another embodiment shown in FIG. 3 shows an example of a lining type in which a high-rigidity plate 31a is covered with a rubber plate 31b.If this type is used, the body 30 will have a high rigidity during pressure molding. Since it is compressed without directly contacting the high rigidity plate 31a, which is a different material, it is also possible to improve the durability of the rubber mold.

Furthermore, although not shown, increasing the vertical wall thickness of the top portion 31 is the simplest and easiest way to impart high rigidity if there is no restriction in the height direction of the device space.

The molding rubber mold 29 is configured to form a powder loading chamber 32 therein and perform compression molding of the powder 33 to be molded.

According to the embodiment of the present invention, the top part 31 of the internal pressurizing rubber mold 28 that receives vertical pressure from a pressure medium is replaced by a highly rigid plate 3 such as a steel plate.
1a and a rubber plate 31b made of a rubber material, which has a high rigidity.As shown in FIG. Even if a vertical force is applied to the top portion 31, the top portion 31 does not undergo a large deflection in the axial direction, and the molded powder 33 can be compression-molded into an accurate ball shape by the molding rubber die 29.

Note that the present invention is applicable not only to dry isostatic presses but also to wet isostatic presses.

(Effects of the invention) According to the invention, the top of the rubber mold, whose lower end is restrained by the lower lid and does not deform, is prevented from bending significantly under axial load, so the amount of deformation is It is excellent in that it can be compressed without any difference in compression, enables uniform compression molding from the upper part in the radial and vertical directions, maintains the isostatic pressing effect, and improves the shape and homogenization of the processed product. It is.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional front view showing an embodiment of the present invention;
Figure 2a is a sectional view showing the state of the rubber mold before deformation;
Figure 2b is a sectional view showing the state of the rubber mold after deformation;
Fig. 3 is a cross-sectional view of the top of another embodiment of the present invention, Fig. 4 is a cross-sectional view of a dry cold isostatic press showing a conventional example, and Fig. 5 shows the state of a conventional rubber mold before deformation. FIG. 6 is a cross-sectional view showing the state after the same deformation. 21... Molded container, 22... Top lid, 23, 25
...Lower lid, 28...Rubber mold, 30...Same part, 31
...Top.

Claims (1)

[Claims for Utility Model Registration] By covering the upper and lower openings of the cylindrical molded container 21 of the cold isostatic press with the upper and lower lids 22, 23, 24, and 25, the inside of the molded container 21 can be A pressurized space is formed, and the upper surface of the lower lids 23, 24, 25 has a cylindrical convex portion 25 that projects into the space.
a rubber mold 28 having a lower end opening fitted onto the protrusion 25; The trunk 30
The top part 31 has a composite structure of a rubber plate 31b and a high-rigidity plate 31a having higher rigidity than the rubber of the body part 30. Rubber mold in cold isostatic press.