JPH0780067B2 - 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. 18, a mold 2 made of a flexible material (for example, neoprene rubber, urethane resin, etc.) and having a long axial length is formed inside the mold 2 and the powder filling space 1. Lids 3, 4 for covering the upper and lower open ends 1a, 1b, a flexible pressure cylinder 5 for externally fitting the mold 2, and a pressure cylinder 5
And a holding case 6 to which the pressure liquid is fitted, and an annular pressure chamber 8 to which the pressurized liquid 7 is supplied is formed between the pressure cylinder 5 and the holding case 6. The holding case 6 has liquid supply / discharge ports 6c, 6d facing the pressure chamber 8. Holding case 6
Has 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 cored bar 9 has bolt portions 9a and 9b extending vertically, and the bolt portions 9a and 9b are inserted into the insertion holes 3a and 4a of the lids 3 and 4, and the nuts 10 are attached to the bolt portions 9a and 9b. , 11 are tightened.
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, a molded product (not shown) obtained inside the mold 2, the mold 2 and the core 9
Is separated from.

[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,
It is discharged from the gap between the bolts 9a, 9b of the cored bar 9 and the nuts 10, 11 to the outside. 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 cored bar 9 and the nuts 10 and 11 becomes long, the compressed air in the high pressure state cannot be completely degassed, and the compressed air is not released into the molded product. To remain.
The compressed air remaining in the molded product causes damage to the molded product when it expands as the pressurized liquid 7 is decompressed. for that reason,
In the conventional powder pressure molding apparatus, the vertical dimension H of the powder filling space 1 is 500 m in order to prevent compressed air from remaining.
It was necessary to shorten it to m or less, and it was not possible to obtain a long molded product.

[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 first invention is to fit a flexible pressure cylinder having a powder filling space having a long axial length inside, and a pressure cylinder. In a powder pressure molding apparatus including a holding case, the outer peripheral surface of the pressure cylinder is provided with a plurality of annular concave grooves which are provided at appropriate intervals in the axial direction of the pressure cylinder. Is divided into a plurality of pressurizing regions, and one pressurizing region selected from these pressurizing regions is set as an initial pressurizing region, and an elastic seal ring is tightly fitted to each of the annular recessed grooves. And a single pressurizing liquid guide surface that is in close contact with all of the elastic seal ring is formed in the holding case,
A pressurized liquid supply port is opened at a portion of the pressurized liquid guide surface facing the initial pressure region.

The gist of the second invention is a powder pressure molding including 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 apparatus, the outer peripheral surface of the pressurizing cylinder has a plurality of pressurizing regions defined by a plurality of annular recessed grooves which are recessed from each other at appropriate intervals in the axial direction of the pressurizing cylinder. One of the pressure areas formed is selected as the initial pressure area,
An elastic seal ring is fitted into each of the annular grooves in an interference fit state, and the holding case is provided with a single pressurized liquid guide surface that comes into close contact with all of the elastic seal rings. A pressurizing liquid supply port is opened at a portion of the pressurizing liquid guide surface facing the initial pressurizing region, and a flexible back-up cylinder is provided inside the pressurizing cylinder.
The elastic coefficient of the cylinder wall constituent material of the back-up cylinder goes from a region corresponding to an initial pressure region formed in the pressure cylinder toward a cylinder wall portion corresponding to an end of the powder filling space. It is designed to grow as it grows.

[Operation] (Operation of the first invention) Third operation of the operation of the first invention will be described.
A description will be given with reference to FIGS. As shown in FIG. 3A, the pressurized liquid 7 is supplied to the pressurized liquid supply port 26c of the holding case 26.
From the initial pressure area 25a on the outer peripheral surface 25a of the pressure cylinder 25
-1 and the pressurized liquid guide surface 26f of the holding case 26 are supplied. Pressure areas 25a-2, 25a adjacent to the initial pressure area 25a-1
-3 and the initial pressurization area 25a-1 are partitioned by the elastic seal rings 35, 35, the pressurized liquid 7 is initially in the initial pressurization area.
By pressing only 25a-1, the initial pressurizing region 25a-1 of the pressurizing cylinder 25 is expanded and deformed inward. The powder 14 in the powder filling space 1 is
Only the region of the pressure cylinder 25 facing the initial pressure region 25a-1 is pressurized. Air in pressurized powder 14 (not shown)
Is to flow out rapidly into the air passage formed by the particle gaps in the unpressurized powder as the air pressure rises and remain in the compressed powder 14 in a compressed state. There is no. When the bending amount of the pressurizing cylinder 25 increases as the total supply amount of the pressurizing liquid 7 increases, the pressurizing cylinder 25 has an annular groove 25b formed on both sides of the initial pressurizing region 25a-1. , 25b are deformed inward, and the outer diameter A of the annular groove decreases. The elastic seal rings 35, 35 fitted in the annular recessed grooves 25b, 25b in an interference fit state are, as shown in FIG.
The outer diameter B of the ring is reduced to reduce the holding case 26
A gap is formed between the liquid and the pressurized liquid guide surface 26f to lose the sealing function. Due to the loss of the sealing function of the elastic seal rings 35, 35, the pressurized liquid 7 flows out to the pressure regions 25a-2, 25a-3 of the pressure cylinder 25 adjacent to the initial pressure region 25a-1. The pressing areas 25a-2 and 25a-3 are pressed. The powder 14 in the powder filling space 1 is pressed in a region of the pressing cylinder 25 that faces the pressing regions 25a-2 and 25a-3. The air (not shown) in the pressurized powder 14 rapidly flows into the air passage in the unpressurized powder because the air pressure rises, and the pressurized powder
It does not remain in compressed state in 14 When the total supply amount of the pressurized liquid 7 further increases, the pressurized liquid 7 is applied to the pressurizing regions 25a-4, 2 on the outer peripheral surface 25a of the pressurizing cylinder 25 as shown in FIG.
5a-5 and pressurizing regions 25a-6, 25a-7 are sequentially pressed in the same manner as above. With the sequential pressurization of the pressurizing cylinder 25, the powder 14 filled in the powder filling space 1 has an initial pressurizing region of the pressurizing cylinder 25.
Ends 1a and 1b from the region in the powder filling space 1 facing 25a-1
Are sequentially pressurized toward. The air present in the powder 14 filled in the powder filling space 1 is a powder that faces the initial pressurizing region 25a-1 of the pressurizing cylinder 25 as the powder 14 is sequentially pressurized. It is squeezed from the region in the filling space 1 toward the ends 1a, 1b. As a result, in the pressed powder 14, the molded article 34
There is no residual compressed air that could lead to damage.

(Operation of Second Present Invention) The operation of the second present invention will be described with reference to FIGS. 9A and 9B showing an embodiment of the present invention. As shown in FIG. 3A, the pressurized liquid 7 is supplied to the pressurized liquid supply port 56c of the holding case 56.
From the initial pressure area 25a on the outer peripheral surface 25a of the pressure cylinder 25
-1 and the pressurized liquid guide surface 56f of the holding case 56. Pressure areas 25a-2, 25a adjacent to the initial pressure area 25a-1
-3 and the initial pressurization area 25a-1 are partitioned by the elastic seal rings 35, 35, the pressurized liquid 7 is initially in the initial pressurization area.
By pressing only 25a-1, the initial pressurizing region 25a-1 of the pressurizing cylinder 25 is expanded and deformed inward. The powder 14 in the powder filling space 1 is
Only the region of the pressure cylinder 25 facing the initial pressure region 25a-1 is pressurized. Air in pressurized powder 14 (not shown)
Because the air pressure rises, it rapidly flows out into the air passage formed by the particle gap in the unpressurized powder, and does not remain in the compressed powder 14 in a compressed state. .
When the amount of bending of the pressurizing cylinder 25 and the back-up cylinder 57 increases as the total supply amount of the pressurizing liquid 7 increases, the pressurizing cylinder 25 is recessed on both sides of the initial pressurizing region 25a-1. The annular recessed grooves 25b, 25b are deformed inward, and the annular recessed groove outer diameter A is reduced. The elastic seal rings 35, 35 fitted in the annular recessed grooves 25b, 25b in an interference fit state are, as shown in FIG.
As the outer diameter A of the annular groove is reduced, the outer diameter B of the ring is reduced, and a gap (not shown) is formed between the holding case 56 and the pressurized liquid guide surface 56f to lose the sealing function. Due to the loss of the sealing function of the elastic seal rings 35, 35, the pressurized liquid 7 flows out to the pressure regions 25a-2, 25a-3 of the pressure cylinder 25 adjacent to the initial pressure region 25a-1. , This pressure area 25a-2,25a
Press -3. The powder 14 in the powder filling space 1 is a pressure cylinder.
The region of 25 that faces the pressure regions 25a-2 and 25a-3 is pressurized. The air (not shown) in the pressurized powder 14 rapidly flows out into the air passage in the unpressurized powder because the air pressure rises, and It does not remain in the compressed state. The pressure of the pressurized liquid 7 is higher than that in the case where only the initial pressure area 25a-1 of the pressure cylinder 25 is pressurized.
The pressure increases when the pressure regions 25a-2 and 25a-3 are pressurized.
The reason is that the elastic coefficient of the back-up cylinder 57 moves from the region of the pressure cylinder 25 facing the initial pressure region 25a-1 toward the open ends 1a and 1b of the powder filling space 1 (see FIG. 6). This is because it is getting bigger and bigger. Due to the phenomenon of increase in the pressing force, the powder 14 initially pressurized in the region in the powder filling space 1 facing the initial pressure region 25a-1 of the pressure cylinder 25 is further pressurized. This increase in pressure is caused by the powder that is initially pressed.
The fine compressed air remaining in 14 will also be discharged, and degassing of the compressed air will be completed. When the supply pressure of the pressurized liquid 7 is further increased, the pressurized liquid 7 is applied to the pressurizing region 25a- on the outer peripheral surface 25a of the pressurizing cylinder 25 as shown in FIG.
4,25a-5 and pressure areas 25a-6, 25a-7 are sequentially pressurized. As the pressurizing cylinder 25 and the back-up cylinder 57 are sequentially pressurized, the powder 14 filled in the powder filling space 1 is compressed by the pressurizing cylinder 25.
From the region in the powder filling space 1 facing the initial pressurizing region 25a-1 to the end portions 1a, 1b are sequentially pressurized. 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.
It is squeezed from the area facing a-1 toward the ends 1a, 1b of the powder filling space 1. As a result, compressed air that would damage the molded product does not remain in the pressed 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, a core metal 9 stretched between the upper and lower lids 3 and 4,
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 29 that are screwed to the upper and lower ends of the outer cylinder 23 and hold the pressure cylinder 25. An annular pressure chamber 28 is formed between the outer cylinder 23 and the inner cylinder 24. The pressure cylinder 25 is made of a flexible material (for example, neoprene rubber, urethane resin, etc.), and its hardness is appropriately selected within the range of JIS rubber hardness of 40 to 90 degrees. On the outer peripheral surface 25a of the pressurizing cylinder 25, annular recessed grooves 25b, 25b ... Are appropriately provided for each pitch P (for example, P = 100 to 300 mm) along the outer peripheral surface longitudinal direction, and are divided into seven parts. Pressure area 2
5a-1, 25a-2, ..., 25a-7 are formed. Of these pressure areas, the central pressure area 25a-1 is the initial pressure area. Each of the annular recessed grooves 25b, 25b ... has an O-shaped cross section and an X-shaped cross section.
Elastic ring 35,3 of appropriate shape such as V-shape or V-shape
5 ... is fitted in an interference fit. In the holding case 26, a pressurized liquid guide surface 26f is formed on the inner surface of the inner cylinder 24 so as to come into close contact with the elastic seal rings 35, 35 ... On the pressurized liquid guide surface 26f, an appropriate number of pressurized liquid supply ports 26c facing the initial pressure region 25a-1 of the pressure cylinder 25,
It is opened so as to communicate with the pressure chamber 28. At the upper side of the pressurized liquid guide surface 26f, the pressurized device 2 is provided via the pressing cylinder 25.
A suitable number of pressurized liquid supply / discharge ports 2 at a position facing the lid 3 of 1.
6 g is opened so as to communicate with the pressure chamber 28. 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 28. The upper and lower pressurized liquid supply / discharge ports 26g and 26h are provided in the holding case 26.
It is provided as necessary to discharge the air interposed between the pressurized liquid guide surface 26f and the pressurizing cylinder 25, and is normally closed at the outer peripheral surface 25a of the pressurizing cylinder 25. Has been done. Since the portions 25c and 25d of the pressurizing cylinder 25 that close the pressurized liquid supply / discharge ports 26g and 26h are backed up by the lids 3 and 4 of the pressurizing target 21, the portions 25c and 25d are flexibly deformed. The closed state is maintained until (see FIG. 4). Liquid supply / discharge ports 23a, 23b facing the pressure chamber 28 are opened in the outer cylinder 23 in the vertical direction. 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 formed on the outer peripheral surface 25a of the pressurizing cylinder 25 is not limited to seven as in the illustrated embodiment, and although not shown, it is not less than two. Anything will do. Further, the initial pressing area is not limited to the central pressing area 25a-1 as shown in the illustrated embodiment, and although not shown in the drawing, a plurality of pressing areas are formed corresponding to the three-dimensional shape of the molding target. Of course, it is possible to select any one of the areas.

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 in the first embodiment will be described. First, as shown in FIG. 1 and FIG.
A pressurized tool 21 in which the powder 14 is filled in the powder filling space 1 is prepared. The pressurized tool 21 is inserted into the pressurizing tool 22 and
It is held in place by the upper and lower clamps 12, 13 screwed onto. 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 pressure chamber via the liquid supply / discharge ports 23a, 23b of the outer cylinder 23. 2
Inflow to 8. When the pressurized liquid 7 in the pressure chamber 28 reaches a predetermined pressure (for example, 50 to 200 kg / cm ² ), the pressurized liquid 7 flows out from the pressurized liquid supply port 26c of the holding case 26 and the initial pressurization of the pressurizing cylinder 25 is performed. It enters between the region 25a-1 and the pressurized liquid guide surface 26f of the holding case 26. The liquid supply / discharge ports 26g, 26h formed on the upper and lower sides of the inner cylinder 24 are firmly closed by the portions 25c, 25d of the pressurizing cylinder 25, so that the pressurizing liquid 7 is supplied to the pressurizing cylinder 25. It will not be drained towards. The pressurized liquid 7 that has flowed out to the initial pressurization region 25a-1 is, as shown in FIG.
Since the upper and lower ends are partitioned by the elastic seal rings 35, 35, only the initial pressurization area 25a-1 is pressed and the initial pressurization area 25a is pressed.
-Expand and deform -1 inward. The mold 2 is a pressure cylinder 25
Only the outer peripheral surface 2a of the area facing the initial pressing area 25a-1 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. Initial pressure area 25 of pressure cylinder 25
With respect to a-1, the amount of deflection increases as the supply amount of the pressurized liquid 7 increases. Initial pressure area 25a-1 in the pressure cylinder 25
As shown in FIG. 3 (B), the portions of the annular recessed grooves 25b, 25b recessed on both sides of are deformed inward to reduce the outer diameter A of the annular recessed groove. The elastic seal rings 35, 35 fitted in the annular recessed grooves 25b, 25b in an interference fit state reduce the ring outer diameter B as the annular recessed groove outer diameter A decreases, and the pressurized liquid in the holding case 26 is compressed. A gap is formed between the guide surface 26f and the sealing function is lost. As the pressurized liquid 7 loses the sealing function of the elastic seal rings 35, 35, as shown in FIG.
Pressure regions 25a-2, 25a-3 adjacent to 25 initial pressure regions 25a-1
And presses the pressure areas 25a-2 and 25a-3. In the mold 2, the outer peripheral surface 2a of the region of the pressing cylinder 25 that faces the pressing regions 25a-2, 25a-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. Powder
It does not remain in compressed state in 14 When the total supply amount of the pressurized liquid 7 further increases, the pressurized liquid 7 is applied to the pressurizing regions 25a-4, 2 on the outer peripheral surface 25a of the pressurizing cylinder 25 as shown in FIG.
5a-5 and pressurizing regions 25a-6, 25a-7 are sequentially pressed in the same manner as above. With the sequential pressurization of the pressurizing cylinder 25, the powder 14 filled in the powder filling space 1 has an initial pressurizing region of the pressurizing cylinder 25.
Ends 1a and 1b from the region in the powder filling space 1 facing 25a-1
Are sequentially pressurized toward. The air present in the powder 14 filled in the powder filling space 1 is a powder that faces the initial pressurizing region 25a-1 of the pressurizing cylinder 25 as the powder 14 is sequentially pressurized. It moves from the region in the filling space 1 toward the ends 1a, 1b and is discharged to the outside from the screw gap between the bolts 9a, 9b of the cored bar 9 and the nuts 10, 11. As a result, compressed air that would damage the molded product does not remain in the pressed powder 14. The entire outer peripheral surface 25a of the pressurizing cylinder 25 and the holding case 2
The pressurized liquid 7 supplied between the pressurized liquid guide surface 26f of 6
Is a predetermined final pressure (for example, 500 to 5,000 kg / cm ² )
The pressure is increased to and the powder 14 is pressure-molded. The pressurized fluid 7 in the pressure chamber 28 is decompressed after the pressure molding for a predetermined time. As shown in FIG. 5, the flexible mold 2 and the pressurizing cylinder 25 spontaneously return to the original mold inner diameter D 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. Pressurized equipment
In nut 21, nuts 10 and 11 and lids 3 and 4 arranged above and below are removed, and molded product 34, core metal 9 and mold 2 are separated.

(Second Embodiment) FIGS. 6 to 11 show a device 40 of the present invention according to a second embodiment. The device 40 of the present invention of the second embodiment is greatly different from the device 20 of the first embodiment of the present invention, in which a back-up cylinder 57 is provided between the pressurizing cylinder 25 held by the holding case 56 and the mold 2. It is the point that was intervened. Back-up cylinder 57
Is a flexible material (for example, neoprene rubber, urethane resin, etc.), and is filled with powder from the area facing the initial pressure area 25a-1 formed on the outer peripheral surface 25a of the pressure cylinder 25. The elastic coefficient is increased as it goes toward the opening ends 1a and 1b of No.1. The back-up cylinder 57 is the sixth
As shown in the figure, a plurality of separately formed ring members 57a, 57b, 57c, 57d having different elastic coefficients are arranged in a line with their respective end faces abutting each other. To obtain the desired elastic modulus, the rubber hardness of the ring material 57a, 57b, 57c, 57d (for example, J
It is generally carried out by appropriately selecting the IS rubber hardness 40 to 90 degrees. As another embodiment of the back-up cylinder 57, as shown in FIG. 8, a plurality of ring members 57a, 57e, 57f, 57g that are formed separately and have different elastic coefficients are arranged in a line, Some are covered with inner and outer layers 57h and 57i. The back-up cylinder 57 is, as in the illustrated embodiment,
Although not shown, the elastic coefficient is not limited to one that is changed stepwise, but the powder filling space 1 is formed from a region facing the initial pressure region 25a-1 formed in the pressure cylinder 25.
Needless to say, the elastic coefficient may be continuously increased toward the open ends 1a and 1b.

Next, the usage procedure and operation of the device 40 of the present invention will be described. First, as shown in FIG. 6 and FIG. 7, the pressurized member 21 filled with the powder 14 in the powder filling space 1 is loaded into the pressing member 22 in the same manner as in the first embodiment. It Next, the pressurized liquid 7 supplied into the pressure chamber 28 has a predetermined pressure (for example, 50 to 200 kg /
cm ² ), the liquid flows out from the pressurized liquid supply port 56c of the holding case 56 and enters between the initial pressure region 25a-1 of the pressure cylinder 25 and the pressurized liquid guide surface 56f of the holding case 56. . The inner cylinder 24
The liquid supply / discharge ports 56g, 56h formed on the upper and lower sides of the lid 49,
The pressurizing liquid 7 does not flow out toward the pressurizing cylinder 25 because the pressurizing liquid 7 is firmly closed by the annular portions 49a, 50a of the valve 50.
Since the pressurized liquid 7 flowing out to the initial pressurizing region 25a-1 is divided by the elastic seal rings 35, 35 at the upper and lower ends of the initial pressurizing region 25a-1 as shown in FIG. 9 (A), Only the initial pressure area 25a-1 is pressed to expand and deform the initial pressure area 25a-1 inward. The mold 2 is the initial pressure region of the pressure cylinder 25.
Only the outer peripheral surface 2a in the area facing 25a-1 is pressed through the back-up cylinder 57 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. In the initial pressurization region 25a-1 of the pressurizing cylinder 25 and the region of the back-up cylinder 57 facing the initial pressurizing region 25a-1, the amount of deflection increases as the total supply amount of the pressurized liquid 7 increases. . As the amount of deflection increases, the pressurizing liquid 7 is pressurized areas 25a-2, 2 adjacent to the initial pressurizing area 25a-1 of the pressurizing cylinder 25, as shown in FIG. 9 (B).
It flows out to 5a-3 and presses the pressure areas 25a-2, 25a-3.
In the mold 2, the outer peripheral surface 2a of the region of the pressurizing cylinder 25 that faces the pressurizing regions 25a-2, 25a-3 is pressed through the back-up cylinder 57 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. Since the pressure of the pressurized liquid 7 that presses the pressurizing regions 25a-2, 25a-3 is such that the elastic coefficients of the ring members 57b, 57b forming the backup cup cylinder 57 are larger than those of the ring member 57a. , As compared with the case where only the initial pressure area 25a-1 is pressurized. Due to the phenomenon of increase in the pressing force, the powder 14 that has been initially pressurized in the region of the pressing cylinder 25 that faces the initial region 25a-1 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 25a-4, 25a-5 and the pressurizing region 25a on the outer peripheral surface 25a of the pressurizing cylinder 25 as shown in FIG. -6 and 25a-7 are sequentially pressurized 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 25a-1 of the pressurizing cylinder 25.
Pressure is sequentially applied from the inner region toward the ends 1a and 1b. The air present in the powder 14 filled in the powder filling space 1 is a powder that faces the initial pressurizing region 25a-1 of the pressurizing cylinder 25 as the powder 14 is sequentially pressurized. Area from filling space 1 to end 1
It moves toward a and 1b and is discharged to the outside from the screwing gap between the bolt portions 9a and 9b of the cored bar 9 and the nuts 10 and 11. As a result, compressed air that would damage the molded product does not remain in the pressed powder 14. Outer peripheral surface of the pressurizing cylinder 25
The pressurized liquid 7 supplied between the entire surface of 25a and the pressurized liquid guide surface 56f of the holding case 56 is further pressurized to a predetermined final pressure (for example, 500 to 5,000 kg / cm ² ) and powder 14 Is pressure-molded. When pressure molding for a predetermined time is completed, pressure chamber
The pressurized fluid 7 in 28 is depressurized. Flexible mold 2,
As shown in FIG. 11, the back-up cylinder 57 and the pressurizing cylinder 25 spontaneously return to the original mold inner diameter D due to their own elastic force as the pressurized liquid 7 is decompressed. Pressurized tool 21
After removing the upper fastener 12 screwed to the holding case 56, the molded product 64 is separated.

(Third Embodiment) FIG. 12 shows an apparatus 70 of the present invention according to a third embodiment. The device 70 of the third embodiment differs from the device 40 of the second embodiment (see FIGS. 6 and 10) in that the structure of the holding case 76 and the upper and lower ends of the pressurizing cylinder 25 are different. The point is that a protective cylinder 77 is interposed between the seal structures 81 and 82 on the side and the back-up cylinder 57 and the mold 2.

The protective cylinder 77 is made of a flexible material (for example, neoprene rubber, urethane resin, etc.), and prevents contact between the lid bodies 3 and 4 of the tool 21 to be pressed and the back-up cylinder body 57. The disconnection protects the back-up cylinder 57.

The holding case 76 includes a rigid outer cylinder 73, and lids 79 and 80 screwed into the upper and lower openings of the outer cylinder 73. The holding case 76 has the pressurizing cylinder 25 fitted on the inner peripheral side thereof, and at the same time, the pressurizing cylinder 25
The surface facing the outer peripheral surface 25a is a pressurized fluid guide surface 76f. On the pressurized liquid guide surface 76f of the outer cylinder 73, an annular distribution groove 73d facing the initial pressure area 25a-1 of the pressure cylinder 25 and an annular distribution groove facing the upper pressure area 25a-6. A groove 73e and an annular distribution groove 73f facing the lower pressure area 25a-7 are provided as recesses. Each of the distribution grooves 73d, 73e, 73f has a pressurized liquid supply / discharge port 7
3c, 73a and 73b are opened. When the pressurized liquid 7 is filled between the pressurized liquid guide surface 76f of the outer cylinder 73 and the pressurized cylinder body 25, the pressurized liquid 7 is further supplied from the central pressurized liquid supply / discharge port 73c and the upper and lower pressurized liquids 7c are supplied. The gas is discharged from the supply / discharge ports 73a and 73b, and deaeration is completely performed.

As shown in FIG. 13, in the seal structure 81 near the upper end of the pressure cylinder 25, the upper edge portion 25e of the pressure cylinder 25 is fitted inside the annular groove 85 formed in the lid 79. , 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 appropriate shape such as an O-shaped, X-shaped, or V-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. 12) near the lower end of the pressurizing cylinder 25 has the same structure as the seal structure 81 near the upper end.

14 (A) and 14 (B) show another embodiment of the seal structure of the pressurizing cylinder 25 near the upper and lower ends. In the seal structure 91, the upper edge portion 25e of the pressurizing cylinder 25 is fitted inside the annular groove 85 formed in the lid 79, and the inner peripheral surface 8 of the annular groove 85 is accommodated.
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.

FIGS. 15 (A) and 15 (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 101, the upper edge portion 25e of the pressurizing cylinder 25 is fitted inside the annular groove 85 formed in the lid 79, 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.

(Fourth Embodiment) FIG. 16 shows an apparatus 110 of the present invention according to a fourth embodiment. The device 110 of the fourth embodiment of the present invention is the same as the third embodiment (first embodiment).
(See FIG. 2) is different from that of FIG. 2 in that the inner surface 57j of the back-up cylinder 57 is a powder pressing surface without a mold and a protection cylinder.

(Fifth Embodiment) FIG. 17 shows an apparatus 120 of the present invention according to a fifth embodiment. The device 120 of the present invention of the fifth embodiment is the same as the device of the third embodiment (first
2)) is different from the inner surface 2'of the pressure cylinder 25 'without the mold, the protection cylinder and the back-up cylinder.
The point 5'j is the powder pressing surface.

(Other Embodiments) As a further aspect of the device of the present invention, although not shown, the back-up cylinder body 57 from the third embodiment shown in FIG. 12 is used.
There is a device that removes.

In each of the above embodiments, a cylindrical or cylindrical molded product is obtained.
The inner peripheral surface 2j of the mold 2 (see FIG. 1), which is the powder pressure molding surface, the inner peripheral surface 57j of the back-up cylinder 57 (see FIG. 16) and the pressure cylinder 25 '(see FIG. 17). The inner peripheral surface 25'j of FIG. 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.

In each of the above embodiments, the outer peripheral surface 25a (2
The shape of 5'a) is 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 molded product. It is possible to squeeze to the end of the powder filling space that does not have any adverse effect, and 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. Sectional views shown in FIGS.
FIG. 11 shows a second embodiment of the device of the present invention. FIG. 6 is a longitudinal sectional view, FIG. 7 is a lateral sectional view taken along line VI-VI of FIG. 6, and FIG. 8 is a back-up tubular body. FIG. 9 (A) and (B) are enlarged longitudinal sectional views of an essential part of another aspect of the present invention. FIG. 10 is an enlarged longitudinal sectional view of an essential part of a pressurized state. FIG. 11 is a vertical cross-sectional view showing a demolded state, FIG. 12 is a vertical cross-sectional view showing a third embodiment of the device of the present invention, FIG. 13 is an enlarged vertical cross-sectional view of the sealing structure of the pressure cylinder, and FIG. Figures (A) and (B) are enlarged views of 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 pressurized state. FIG. 15 (A) and (B) are enlarged views of another embodiment of the sealing structure of the pressurizing cylinder, and FIG. 15 (A) is a vertical sectional view in a non-pressurized state. Figure (B) is a vertical sectional view in a pressurized state, and Figure 16 is the device of the present invention. 4 a longitudinal sectional view showing an embodiment of FIG. 17 is a longitudinal sectional view showing a fifth embodiment of the present invention apparatus, FIG. 18 is a longitudinal sectional view showing a conventional powder pressing apparatus. 1 ... powder filling space, 2 ... mold 3,4 ... lid, 25 (25 ') ... pressurizing cylinder 25a ... outer peripheral surface, 25a-1 ... initial pressurizing area 26 (56, 76) …… Holding case 35 …… Elastic seal ring, 57 …… Back up cylinder 77 …… Protection cylinder

Claims (12)

[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 outer peripheral surface of the pressurizing cylinder is divided into a plurality of pressurizing regions by a plurality of annular recessed grooves which are provided at appropriate intervals in the axial direction of the pressurizing cylinder. One of the pressure areas is selected as an initial pressure area, an elastic seal ring is fitted into each of the annular recessed grooves in an interference fit state, and the holding case is provided with the elastic seal. One pressurizing liquid guide surface that is in close contact with all of the rings is formed, and a pressurizing liquid supply port is opened at a portion of the pressurizing liquid guide surface facing the initial pressurizing region. Powder pressure molding equipment. 2. The powder pressure molding apparatus according to claim 1, wherein the inner 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. 6. A powder pressure molding apparatus comprising a flexible pressure cylinder having a powder filling space having a long axial length formed inside, and a holding case for externally fitting the pressure cylinder. The outer peripheral surface of the pressurizing cylinder is formed with a plurality of pressurizing regions defined by a plurality of annular recessed grooves that are recessed at appropriate intervals in the axial direction of the pressurizing cylinder. One pressure area selected from the pressure areas is the initial pressure area, each of the annular groove is fitted with an elastic seal ring in an interference fit state, the holding case, A single pressurized liquid guide surface is formed that is in close contact with all of the elastic seal rings,
A pressurizing liquid supply port is opened at a portion of the pressurizing liquid guide surface facing the initial pressurizing region, and a flexible back-up cylinder is provided inside the pressurizing cylinder, and the back-up is provided. The elastic coefficient of the cylinder wall constituent material of the cylinder increases as it goes from the region corresponding to the initial pressure region formed in the pressure cylinder toward the cylinder wall portion corresponding to the end of the powder filling space. A powder pressure molding apparatus, characterized in that 7. The powder pressure molding apparatus according to claim 6, wherein an inner surface of the back-up cylinder is a powder pressing surface. 8. The powder pressure molding apparatus according to claim 6, wherein a flexible mold is fitted in the back-up cylinder. 9. The powder pressure molding apparatus according to claim 8, wherein a protective cylinder is provided between the back-up cylinder and the mold. 10. The powder pressure molding apparatus according to claim 6, 7, 8 or 9, wherein the pressure cylinder and the back-up cylinder are integrally formed. 11. A core bar penetrating in the axial direction in the powder filling space, as claimed in claims 6 and 7.
The powder pressure molding device according to item (8), item (9) or item (10). 12. The elastic coefficient of the back-up cylinder is continuous or so that it goes from the region facing the initial pressure region formed in the pressure cylinder toward the open end of the powder filling space. The powder pressure-molding apparatus according to claim 6, 7, 8, 9 or 10, wherein the powder pressure molding apparatus is configured to be gradually increased.