JPH0780068B2 - Powder pressure molding equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is an improvement of a powder pressure molding apparatus for isostatically molding powder by a dry method. The present invention relates to a technique for drawing air to a place where it does not adversely affect a molded product.

[Prior Art] Conventionally, a powder pressure molding apparatus for performing hydrostatic molding by a dry method is
As shown in FIG. 11, a mold 2 made of a flexible material (for example, neoprene rubber, urethane resin, etc.) and having a vertically long powder filling space 1 formed inside and a powder filling space 1 Lids 3,4 for covering the upper and lower open ends 1a, 1b
And a flexible pressure cylinder 5 to which the mold 2 is fitted, and a holding case 6 to which the pressure cylinder 5 is fitted.
An annular pressure chamber 8 to which the pressurized liquid 7 is supplied is formed between the holding case 6 and the holding case 6. The holding case 6 has liquid supply / discharge ports 6c, 6d facing the pressure chamber 8. The holding case 6 is formed with a through hole 6a penetrating in the vertical direction, and the pressurizing cylinder 5 is fitted in the through hole 6a. Between the upper and lower lids 3 and 4, a cored bar 9 which vertically penetrates the center of the powder filling space 1 is detachably stretched. The core metal 9 has bolt portions 9a and 9b extending vertically, and the bolt portions 9a and 9a are inserted into the through holes 3a and 4a of the lids 3 and 4, respectively.
b is inserted, and nuts 10 and 11 are tightened to the bolt portions 9a and 9b. The mold 2 is inserted into the pressurizing cylinder 5 from the through hole 6a of the holding case 6 while being covered with the upper and lower covers 3 and 4, and is screwed into the upper and lower openings 6e and 6f of the holding case 6. It is held by the tightened fasteners 12 and 13.

Next, the usage of the conventional powder pressure molding apparatus configured as described above will be described according to the work procedure. First, the upper clamp 12 screwed to the holding case 6 is removed, and the mold 2
Is removed from the holding case 6. The upper nut 10 and the lid 3 arranged above the mold 2 are removed, and the powder 14 is filled in the powder filling space 1. The upper end of the powder filling space 1 filled with the powder 14 is covered with the lid 3, and the nut 10 is tightened to the bolt 9a of the cored bar 9. The mold 2 is inserted from the through hole 6a of the holding case 6 into the inside of the pressurizing cylinder 5, and the fastener 12 is tightened in the opening 6e of the holding case 6 to complete the pre-press preparation. Next, the liquid supply / discharge port 6 of the holding case 6 is inserted into the pressure chamber 8 formed between the holding case 6 and the pressurizing cylinder 5.
A pressurized liquid 7 having a desired pressure is supplied from c and 6d. Although not shown in the figure, the flexible pressurizing cylinder 5 expands inwardly with the supply of the pressurizing liquid 7 and presses substantially the entire outer surface 2a of the mold 2 at the same time. The flexible mold 2 receives the pressing force from the pressurizing cylinder 5 to reduce the inner diameter D of the mold and simultaneously press the entire powder 14 in the powder filling space 1 at substantially the same time. The air present in the powder 14 is the pressurized liquid 7
As the air pressure increases as the pressure rises,
The air passes through the air passages formed by the particle gaps toward the lids 3 and 4, and is discharged to the outside from the screw gaps between the bolts 9a and 9b of the cored bar 9 and the nuts 10 and 11. After pressurization for a predetermined time, the pressurized liquid 7 in the pressure chamber 8 is discharged from the liquid supply / discharge ports 6c, 6d. The flexible mold 2 and the pressure cylinder 5 are
As the pressurized liquid 7 is decompressed, the original mold inner diameter D is naturally restored by its own elastic force. Subsequently, the upper fastener 12 screwed to the holding case 6 is removed, and the mold 2 is pulled out from the holding case 6. Finally, the molded product (not shown) obtained inside the mold 2, the mold 2 and the cored bar 9 are separated.

[Problems to be Solved by the Invention] As described above, the air present in the powder 14 increases in air pressure as the pressure of the pressurized liquid 7 increases, so that the fine particles in the powder 14 are finely divided. Pass through the air passage toward the lids 3 and 4,
The bolts 9a and 9b of the cored bar 9 and the nuts 10 and 11 are discharged from the screwing gap. By the way, in order to quickly discharge the air intervening in the powder 14 and prevent the air from remaining, it is necessary that the air pressure is high and the air passage formed by connecting the particle gaps of the powder 14 is large. Is. In order to increase the air pressure, it is necessary to increase the pressure of the pressurized liquid 7. However, the air passage formed by the continuous particle gaps of the powder 14 becomes extremely narrow or closed due to the pressurization of the powder 14. Thus, increasing the air pressure and enlarging the air passage are contradictory matters.

In the conventional powder pressure molding apparatus, along with the supply of the pressurized liquid 7, the entire molding processing region of the mold 2 is pressed at substantially the same time, and the mold inner diameter D is reduced. As a result, in the conventional powder pressure molding apparatus, the pressure increase of the air in the powder 14 and the decrease or blockage of the particle gap of the powder 14 simultaneously proceed over the entire powder filling space 1. As a result, the above-mentioned trade-offs could not be solved at all, and the following problems were brought about. That is, when the lengthwise dimension H of the powder filling space 1 is increased, the powder 14 filled in the central portion of the powder filling space 1 becomes
Since the distance between the bolts 9a and 9b of the core metal 9 and the nuts 10 and 11 is increased, the compressed air in the high pressure state cannot be completely degassed and compressed into the molded product. Air remains. The compressed air remaining in the molded product causes damage to the molded product when it expands as the pressurized liquid 7 is decompressed. Therefore, in the conventional powder pressure molding apparatus, the lengthwise dimension H of the powder filling space 1 is set to prevent compressed air from remaining.
It was necessary to shorten the length to 500 mm or less, and a long molded product could not be obtained.

[Object of the Invention] In view of the above problems, an object of the present invention is to provide a powder pressure molding apparatus capable of obtaining a long molded product without containing compressed air in the molded product.

[Means for Solving the Problems] The gist of the present invention is to provide a flexible pressure cylinder having a powder filling space with a long axial length formed inside, and a holding case for externally fitting the pressure cylinder. In the powder pressure molding apparatus, the pressure cylinder has an appropriate local portion located between both ends of the pressure cylinder as an initial pressure region, and the cylinder part of the pressure cylinder is The elastic modulus of the component is made to increase continuously or stepwise from the initial pressure region toward the end of the pressure cylinder, and the holding case has an outer peripheral surface of the pressure cylinder. Is formed, and a pressurized liquid supply port is opened in a portion of the pressurized liquid guide surface facing the initial pressure area of the pressure cylinder.

[Operation] The operation of the present invention will be described based on FIGS. 3 (A) and 3 (B) showing an embodiment. As shown in FIG. 7A, the pressurized liquid 7 is applied from the pressurized liquid supply port 26 c of the holding case 26 to the outer peripheral surface 25 a of the pressing cylinder 25 in the initial pressurizing region 25-1 and the holding case 26. It is supplied between the pressurized liquid guide surface 26f. The pressurized liquid 7 is
First, only the initial pressure area 25-1 is pressed to expand and deform only the initial pressure area 25-1 of the pressure cylinder 25 inward. The reason is that the elastic modulus of the initial pressure area 25-1 is equal to the pressure area 25-2, 25-3.
Since it is smaller than the elastic modulus of
Is easily deformed. Powder in powder filling space 1
As for 14, only the area of the pressing cylinder 25 facing the initial pressing area 25-1 is pressed. The air (not shown) in the pressurized powder 14 rapidly flows out into the air passage formed by the particle gap in the unpressurized powder because the air pressure rises, and the pressure is increased. It does not remain in the compressed powder 14 in a compressed state. The pressurized liquid 7 flows out between the pressurized regions 25-2 and 25-3 of the pressurizing cylinder 25 and the pressurized liquid guide surface 26f of the holding case 26 as the supply pressure increases, Pressurized area 25-2,25
-Expand and deform -3 inward. Powder in powder filling space 1 14
The area of the pressurizing cylinder 25 facing the pressurizing areas 25-2 and 25-3 is pressurized. Air in pressurized powder 14 (not shown)
The air pressure rises so that it rapidly flows into the air passage in the unpressurized powder and does not remain in the compressed powder 14 in a compressed state. The pressure of the pressurized liquid 7 is higher when the pressure areas 25-2 and 25-3 are pressurized than when only the initial pressure area 25-1 of the pressure cylinder 25 is pressurized. Due to the phenomenon of increase in the pressing force, the powder 14 initially pressed in the area in the powder filling space 1 facing the initial pressing area 25-1 of the pressing cylinder 25 is further pressed. This phenomenon of increasing the pressing force also discharges the fine compressed air remaining in the powder 14 that has been initially pressurized, and completes the degassing of the compressed air. When the supply pressure of the pressurized liquid 7 is further increased, the pressurized liquid 7 is supplied to the outer peripheral surface 25a of the pressurizing cylinder 25 as shown in FIG.
The pressurizing regions 25-4, 25-5 and the pressurizing regions 25-6, 25-7 in the above are sequentially pressurized in the same manner as described above. With the sequential pressurization of the pressurizing cylinder 25, the powder 14 filled in the powder filling space 1 faces the initial pressurizing region 25-1 of the pressurizing cylinder 25. Pressure is sequentially applied from the inner region toward the ends 1a and 1b. The air intervening in the powder 14 filled in the powder filling space 1 is accompanied by the sequential pressurization of the powder 14, and as shown in FIG. -Powder filling space 1 facing -1
The area is narrowed toward the ends 1a and 1b. As a result, compressed air that would damage the molded article 39 does not remain in the pressurized powder 14.

[Description of Examples] Next, a powder pressure molding apparatus according to the present invention (hereinafter, referred to as "invention apparatus") will be described based on Examples shown in the drawings.

(First Embodiment) FIGS. 1 to 5 show a first embodiment. The device 20 of the present invention comprises a pressurizing tool 21 and a pressurizing tool 22.

The pressurized tool 21 has the same structure as the conventional one, and includes a flexible mold 2 having a vertically long powder filling space 1 formed therein, and upper and lower open ends 1a of the powder filling space 1. Lids 3 and 4 for covering 1b, and a core metal 9 stretched between the upper and lower lids 2 and 3,
It consists of nuts 10 and 11 screwed to bolts 9a and 9b of a cored bar 9. The cored bar 9 has an appropriate cross-sectional shape such as a circular shape, an elliptical shape, or a polygonal shape, and one or a plurality of the cored bars 9 are stretched. When obtaining a solid molded product, the core metal 9
Are not stretched in the mold 2.

The improvement in the device 20 of the present invention is the pressing tool 22.
In the pressure tool 22, a pressure cylinder 25 is fitted inside a holding case 26. The holding case 26 includes a rigid outer cylinder 23, an inner cylinder 24 that backs up the pressure cylinder 25, and upper and lower lids 31 that are screwed to the upper and lower ends of the outer cylinder 23 to hold the pressure cylinder 25. 32, and an annular pressure chamber 38 is formed between the outer cylinder 23 and the inner cylinder 24. The pressurizing cylinder 25 is made of a flexible material (for example, neoprene rubber, urethane resin, etc.), and has a core layer 27 covered with a coating layer 28. The core material layer 27 is composed of ring materials 27a, 27b, 27c, 27d, etc., each of which is formed separately and has an appropriate length L (for example, L = 100 to 300 mm), in a state of being in contact with their respective end faces. It is arranged. Each ring material 27a, 27
The elastic coefficients of b, 27c and 27d increase as they go from the central ring material 27a toward the open ends 1a and 1b of the powder filling space 1. To obtain the desired longitudinal elastic modulus, the rubber hardness of the ring materials 27a, 27b, 27c, 27d (for example, JIS rubber hardness 40
It is generally performed by appropriately selecting (about 90 degrees). The pressurizing cylinder 25 is not limited to one in which the core layer 27 is covered with the covering layer 28, and although not shown,
Of course, it may be formed only from the core material layer 27. The pressurizing cylinder 25 is
The pressure areas 25-1, 25-2, ..., 25-7 divided into seven are formed,
The central pressure area 25-1 is defined as the initial pressure area. The holding case 26 has a pressurized liquid guide surface 26f formed on the inner surface of the inner cylinder 24 so as to come into close contact with the outer peripheral surface 25a of the pressure cylinder 25. On the pressurized liquid guide surface 26f, the initial pressure area 2 of the pressure cylinder 25 is
A suitable number of pressurized liquid supply ports 26c are opened in a portion facing 5-1 so as to communicate with the pressure chamber 38. At the upper side of the pressurized liquid guide surface 26f, the pressurizing tool 21 is interposed via the pressurizing cylinder 25.
A suitable number of pressurized liquid supply / discharge ports 26 at positions facing the lid body 3 of
g is opened so as to communicate with the pressure chamber 38. Below the pressurized liquid guide surface 26f, a suitable number of pressurized liquid supply / discharge ports 26h are provided at positions facing the lid 4 of the tool 21 to be pressed via the pressurizing cylinder 25. It is opened to communicate with 38. The pressurized liquid supply / discharge ports 26g and 26h are provided as necessary in order to discharge the air interposed between the pressurized liquid guide surface 26f of the holding case 26 and the pressure cylinder 25. ,
It is closed by the outer peripheral surface 25a of the pressurizing cylinder 25. Portions 25c, 25d of the pressurizing cylinder 25 that close the pressurizing liquid supply / discharge ports 26g and 26h.
Since it is backed up by the lids 3 and 4 of the pressurized tool 21, the closed state is maintained until the portions 25c and 25d are flexibly deformed (see FIG. 4). In the outer cylinder 23, in the vertical direction,
Liquid supply / discharge ports 23a, 23b facing the pressure chamber 38 are opened.
The liquid supply / discharge ports 23a, 23b are connected to liquid supply / discharge pipes of a pressurized liquid supply / discharge device (not shown).

The number of divisions of the pressurizing region in which the pressurizing cylinder 25 is formed is not limited to the number of seven parts as shown in the illustrated embodiment, and although not shown, it may be two or more. Good. Further, the initial pressure region is not limited to the central pressure region 25-1 as in the illustrated embodiment, and any of a plurality of pressure regions formed corresponding to the three-dimensional shape of the molding target. Of course, it is also possible to select one.

The device 20 of the present invention is a powder filling space 1 in the illustrated embodiment.
The major axis of the powder filling space 1 coincides with the vertical direction, but the present invention is not limited to this, and although not shown, the major axis of the powder filling space 1 may be inclined or horizontal. Good.

Next, the use procedure and operation of the device 20 of the present invention will be described. First, as shown in FIG. 1 and FIG. 2, a pressurized tool 21 in which the powder 14 is filled in the powder filling space 1 is prepared. Pressurized tool 21
Is inserted into the pressure tool 22 and held in place by the upper and lower clamps 12, 13 screwed to the pressure tool 22. Next, the pressurized liquid 7 (for example, oil, glycerin, boric acid water, etc.) supplied from the pressurized liquid supply device (not shown) is supplied to the outer cylinder 23.
It flows into the pressure chamber 38 via the liquid supply / discharge ports 23a, 23b. The pressurized liquid 7 in the pressure chamber 38 has a predetermined pressure (for example, 50 to 200 k).
g / cm ² ), it flows out from the pressurized liquid supply port 26c of the holding case 26 and is between the initial pressure region 25-1 of the pressurizing cylinder 25 and the pressurized liquid guide surface 26f of the holding case 26. Flow into. In addition, the pressurized liquid supply / discharge ports 26g, 26h formed on the upper and lower sides of the inner cylinder 24.
Is firmly closed by the portions 25c and 25d of the pressurizing cylinder 25, the pressurized liquid 7 does not flow out toward the pressurizing cylinder 25. The pressurized liquid 7 flowing out to the initial pressurizing region 25-1 first presses only the initial pressurizing region 25-1 as shown in FIG. Inflate and deform 25-1 inward. The reason is that since the elastic modulus of the initial pressure region 25-1 is smaller than the elastic modulus of the pressure regions 25-2 and 25-3, the initial pressure region 25-1 is easily deformed. . With the expansion deformation of the initial pressure area 25-1 of the pressure cylinder 25, only the outer peripheral surface 2a of the area of the mold 2 facing the initial pressure area 25-1 of the pressure cylinder 25 is pressed, The powder 14 is pressurized. The air (not shown) in the pressurized powder 14 rapidly flows out to the air passage formed by the large particle gap in the unpressurized powder because the air pressure rises, and the pressure is increased. Powder
It does not remain in the compressed state in 14. Pressure cylinder
The initial pressurizing region 25-1 of 25 is adjacent to the initial pressurizing region 25-1 of the pressurizing cylinder 25 as shown in FIG. Flow into the pressurizing regions 25-2 and 25-3, and press the pressurizing regions 25-2 and 25-3. Mold 2
The outer peripheral surface 2a of the region of the pressure cylinder 25 facing the pressure regions 25-2 and 25-3 is pressed to press the powder 14. The air (not shown) in the pressurized powder 14 rapidly flows out to the air passage formed by the large particle gap in the unpressurized powder because the air pressure rises, and the pressure is increased. It does not remain in the compressed powder 14 in a compressed state. The pressure of the pressurized liquid 7 is higher when the pressure areas 25-2 and 25-3 are pressurized than when only the initial pressure area 25-1 of the pressure cylinder 25 is pressurized. Due to the phenomenon of increase in the pressing force, the powder 14 initially pressed in the area in the powder filling space 1 facing the initial pressing area 25-1 of the pressing cylinder 25 is further pressed. This phenomenon of increasing the pressing force also discharges the fine compressed air remaining in the powder 14 that has been initially pressurized, and completes the deaeration of the compressed air. When the supply pressure of the pressurized liquid 7 is further increased, the pressurized liquid 7 is applied to the pressurizing regions 25-4, 25-5 and the pressurizing region 25 on the outer peripheral surface 25a of the pressurizing cylinder 25 as shown in FIG. -6 and 25-7 are sequentially pressurized as above. With the sequential pressurization of the pressurizing cylinder 25,
The powder 14 filled in the powder filling space 1 is a pressure cylinder.
From the region in the powder filling space 1 facing the initial pressure region 25-1 of 25, the pressure is sequentially applied toward the ends 1a and 1b. The air intervening in the powder 14 filled in the powder filling space 1 is the initial pressurizing region 25 of the pressurizing cylinder 25 as the powder 14 is sequentially pressed.
-1 is moved from the area in the powder filling space 1 facing the end portions 1a, 1b to the bolt portions 9a, 9b and nuts 10, 11 of the core metal 9.
It is discharged from the screwing gap with the outside. As a result, compressed air that would damage the molded product does not remain in the pressed powder 14. The pressurized liquid 7 supplied between the entire outer peripheral surface 25a of the pressurizing cylinder 25 and the pressurized liquid guide surface 26f of the holding case 26 has a predetermined final pressure (for example, 500 to
The pressure is increased to 5,000 kg / cm ² ) and the powder 14 is pressure molded.
The pressurized fluid 7 in the pressure chamber 38 is decompressed after the pressure molding for a predetermined time. As shown in FIG. 5, the flexible mold 2 and the pressurizing cylinder 25 naturally return to the original mold inner diameter D state due to their own elastic force as the pressurizing liquid 7 is depressurized. The pressurized tool 21 is extracted from the holding case 26 after removing the upper fastening tool 12 screwed to the holding case 26. The pressurized tool 21 includes nuts 10 and 11 arranged vertically.
The lids 3 and 4 are removed, and the molded product 39, the cored bar 9 and the mold 2 are separated.

(Second Embodiment) FIG. 6 shows a device 40 of the present invention according to a second embodiment. The device 40 of the present invention of the second embodiment differs from the device 20 of the first embodiment described above in that the structure of the holding case 46 and the sealing structures 81, 82 near the upper and lower ends of the pressurizing cylinder 25 are added. The protection cylinder 77 is interposed between the pressure cylinder 25 and the mold 2.

The holding case 46 includes a rigid outer cylinder 43 and lids 44 and 45 screwed into the upper and lower openings of the outer cylinder 43. The holding case 46 has the pressurizing cylinder 25 fitted on the inner peripheral side thereof, and also has the pressurizing cylinder 25.
A surface facing the outer peripheral surface 25a is a pressurized liquid guide surface 46f. On the pressurized liquid guide surface 46f of the outer cylinder 43, an annular distribution concave groove 43d facing the initial pressure area 25-1 of the pressure cylinder 25 and an annular distribution concave groove facing the upper pressure area 25-6. A groove 43e and an annular distribution groove 43f facing the lower pressure area 25-7 are provided as recesses. Each of the distribution grooves 43d, 43e, 43f has a pressurized liquid supply / discharge port 43.
C, 43a and 43b are opened. When the pressurized liquid 7 is filled between the pressurized liquid guide surface 46f of the outer cylinder 43 and the pressurized cylinder body 25, the pressurized liquid 7 is further supplied from the central pressurized liquid supply / discharge port 43c and the upper and lower pressurized liquids The gas is discharged from the supply / discharge ports 43a and 43b, and deaeration is completely performed.

The protection tube 77 is made of a flexible material (for example, neoprene rubber, urethane resin, etc.), and the lids 3 and 4 of the tool 21 to be pressed contact the pressure tube 25. By cutting off, the pressure cylinder 25 is protected.

As shown in FIG. 7, the seal structure 81 near the upper end of the pressurizing cylinder 25 has an upper edge portion 25e of the pressurizing cylinder 25 fitted inside an annular groove 85 formed in the lid 44. , The outer peripheral surface 25 of the upper edge 25e
A seal ring fitting groove 86 is provided on the a side, and a seal ring 87 fitted in the seal ring fitting groove 86 and having an arbitrary shape such as an O-shaped, V-shaped, or X-shaped cross section is provided in the annular groove 85. The inner recess 85b of the annular groove 85, which is in close contact with the peripheral surface 85a, serves as the back-up portion of the upper edge portion 25e. The seal structure 82 (see FIG. 6) near the lower end of the pressurizing cylinder 25 has the same structure as the seal structure 81 near the upper end.

FIGS. 8 (A) and 8 (B) show an embodiment of another mode of the seal structure near the upper and lower ends of the pressurizing cylinder 25. In the seal structure 91, the upper edge portion 25e of the pressurizing cylinder 25 is housed inside the annular groove 85 formed in the lid 44, and the inner peripheral surface 8 of the annular groove 85 is
A seal ring fitting groove 96 is recessed in the 5a, and the seal ring 97 fitted in the seal ring fitting groove 96 is an upper edge portion of the pressurizing cylinder 25.
The inner deep part 85b of the annular groove 85 is closely contacted with 25e and is used as the back-up part of the upper edge part 25e.

9 (A) and 9 (B) show another embodiment of the seal structure of the pressurizing cylinder 25 near the upper and lower ends. In the seal structure 101, the upper edge portion 25e of the pressurizing cylinder 25 is fitted inside the annular groove 85 formed in the lid body 44, and the outer peripheral surface of the upper edge portion 25e.
25a and the inner peripheral surface 85a of the annular groove 85, the seal ring fitting groove 10
8,109 are recessed to face each other, and both seal ring fitting grooves 10
The seal rings 107 fitted in the 8, 109 are closely attached to the bottom surfaces 108a, 109a of the seal ring fitting grooves 108, 109, and the inner depth 85b of the annular groove 85 is used as the back-up portion of the upper edge 25e.

(Third Embodiment) FIG. 10 shows an apparatus 110 of the present invention according to a third embodiment. The device 110 of the third embodiment differs from the device 110 of the second embodiment (see FIG. 6) in that the inner surface 25'j of the pressurizing cylinder 25 'is powdered without the need for a mold and a protective cylinder. This is the point where the surface is pressed.

(Other Examples) In each of the above examples, a cylindrical or circumferential molded product is obtained.
The inner peripheral surface 2j of the mold 2 (see FIG. 1) and the inner peripheral surface 25'j of the pressurizing cylinder 25 '(see FIG. 10), which are the powder pressure molding surfaces, are all circumferential surfaces. Is. However, the shape of the powder pressure molding surface is not limited to the circumferential surface, and although not shown in the drawing, various inner surface shapes according to the three-dimensional shape of the molding target are possible. Further, in the above embodiment, the pressurizing cylinder 25 (25 ')
The outer peripheral surface 25a (25'a) has a circumferential surface. However, the outer surface of the pressurizing cylinder is not limited to the circumferential surface, and although not shown, various outer surface shapes are possible so that the molding pressure corresponding to the three-dimensional shape of the molding object can be obtained. Is.

[Effects of the Present Invention] As described in detail above, the device of the present invention has the following excellent effects.

The device of the present invention can increase the pressure applied to the powder filled in the powder filling space in the direction from the initial pressurizing region toward the end portion in sequence, so that the compressed air in the powder is substantially applied to the formed product. It is possible to squeeze to the end of the powder-filled space that does not adversely affect the above, and the compressed air is not contained in the powder.

Since the device of the present invention can completely separate the powder and the compressed air, the molded product will not be damaged at the time of demolding.

According to the confirmation test by the present inventor, the ceramic powder is pressure-molded to have an outer diameter of 300 mmφ, an inner diameter of 240 mmφ, a length of 4,
It was possible to obtain a hollow molded product of 000 mm. As is clear from this confirmation test, the device of the present invention makes it possible to obtain a long molded product which has been impossible in the past.

[Brief description of drawings]

1 to 5 show a first embodiment of the device of the present invention, wherein FIG. 1 is a longitudinal sectional view and FIG. 2 is II-II of FIG.
Fig. 3 (A) and (B) are enlarged vertical sectional views of the main part under pressure, Fig. 4 is a vertical sectional view showing a pressed state, and Fig. 5 is a demolded state. FIG. 6 is a vertical sectional view showing the second embodiment of the device of the present invention, FIG. 7 is an enlarged vertical sectional view of the sealing structure of the pressurizing cylinder, and FIGS. 8 (A) and 8 (B).
9A and 9B are enlarged views of another embodiment of the sealing structure of the pressurizing cylinder. FIG. 19A is a vertical sectional view in a non-pressurized state, FIG. Figures (A) and (B) are enlarged views of still another embodiment of the sealing structure of the pressurizing cylinder, where (A) is a longitudinal sectional view in a non-pressurized state, and (B) is a pressurizing state. FIG. 10 is a vertical sectional view showing a state of the present invention, FIG. 10 is a vertical sectional view showing a third embodiment of the apparatus of the present invention, and FIG. 11 is a vertical sectional view showing a conventional powder pressure molding apparatus. 1 ... powder filling space, 2 ... mold 3,4 ... lid, 25 (25 ') ... pressurizing cylinder 25a ... outer peripheral surface, 25-1 ... initial pressurizing area 26 (46) …… Holding case, 77 …… Protective tube

Claims (5)

[Claims] 1. A powder pressure molding apparatus comprising a flexible pressure cylinder having a powder filling space with a long axial length formed inside, and a holding case for externally fitting the pressure cylinder. The pressure cylinder is
An appropriate local portion located between both ends of the pressurizing cylinder is used as an initial pressurizing region, and the elastic coefficient of the tubular portion constituent material of the pressurizing cylinder is from the initial pressurizing region. The holding case is formed with a pressurized liquid guide surface facing the outer peripheral surface of the pressurizing cylinder. The powder pressure molding apparatus is characterized in that a pressure liquid supply port is opened at a portion facing the initial pressure region of the pressure cylinder. 2. The powder pressure molding apparatus according to claim 1, wherein the inner peripheral surface of the pressure cylinder is a powder pressure surface. 3. The powder pressure molding apparatus according to claim 1, wherein a flexible mold is fitted in the pressure cylinder. 4. The powder pressure molding apparatus according to claim 3, wherein a protective cylinder is interposed between the pressure cylinder and the mold. 5. A cored bar penetrating in the axial direction in the powder filling space.
The powder pressure molding device according to item 3, item 3 or item 4.