JPS6364278B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a powder compression molding device, and in particular to a compression molding device that controls the mutual movement of an upper punch, a die, and a lower punch during powder compression molding to enable good powder compression. This invention relates to powder molding equipment.

Further, the present invention aims to enable stable and good powder compression in such a powder compacting device, to facilitate molding into various shapes, and at the same time to improve the workability of the compacting device. It is something to do.

In general, various improvements have been made in compression molding of powder to make the density of the powder constant in the compression direction.
An example is shown in FIG.

In the forming apparatus shown in FIG. 1, the upper ram plate 21, the upper punch 5, and the cylinder 8 are attached to the upper ram 2, the die 3 is attached to the die table 31, and the lower punch 6 is attached to the lower punch plate 61. ing. The die table 31 is connected to the lower ram 4,
The lower ram 4 is connected to a filling cylinder 9.

Powder filling is performed by injecting pressurized fluid into the filling cylinder 9, pushing up the lower ram 7 and die table 31, and reciprocating the die table 31 into the space formed by the die 3, core rod 4, and lower punch 6. Powder is filled with a feeder.

After filling is completed, the upper ram 2 descends and enters the powder compression process. However, if the lower punch 6 and die 3 are fixed and compression is performed only by the upper punch 5, the upper and lower rams may Since a density difference occurs and becomes a problem, the following control is performed. That is, when the upper ram 2 descends and the upper punch 5 enters the compression process, the piston rod 81 of the upper cylinder 8 attached to the upper ram plate 21 hits the die table 31 and pushes the die table 31 down. At this time, by adjusting the relief valve 17 and adjusting the equilibrium pressure of the cylinder 8, the piston rod 8
1 and adjust the amount by which the die table 31 is pushed. For example, when the relief valve 17 is almost open, the piston rod 81 does not push the die table 31, and when the relief valve 17 is closed, the piston rod 81 is almost fixed, and the lowering amount of the upper ram 2 and the die table 31 are The amount of fall is approximately equal.

Normally, by lowering the die table 31 by about half of the lowering amount of the upper ram 2, it is possible to form a green compact with uniform density on the upper and lower sides, so the relief valve 17 is adjusted accordingly. .

Compared to mechanical control using cams, etc., methods that use such hydraulic cylinders to control powder compaction are capable of releasing pressure even if an abnormally high compression state occurs. In various types of molding devices, such as hydraulic type, etc., it has been used to control the relative positions of the upper punch 2, lower punch 6, and die 3 during powder compression.

On the other hand, with such conventional molding equipment, it is necessary to adjust the relief valve whenever the shape to be molded changes, and the adjustment of the relief valve is delicate, resulting in poor workability as well as continuous operation for long periods of time. When molding was repeated, there were problems such as deviations from the initial set.

Furthermore, since the piston rod 81 comes into contact with the die table 31, there is a problem in that the usable effective area of the die table 31 is limited.

The present invention solves these problems,
In particular, a powder molding apparatus is obtained which is excellent in productivity such as stable powder molding and workability. This embodiment of the invention is shown in FIGS. 2 and 3.

The gist of the present invention is that the upper ram 2 that fixes the upper punch 5 is provided with a push rod 22 that pushes the upper piston rod 121 of the upper cylinder 12, and the lower ram 7 or die table 31 that fixes the die 3 is provided with a push rod 22 that pushes the upper piston rod 121 of the upper cylinder 12. The lower piston rod 131 of the lower cylinder 13 is fixed, and the lower cylinder 13 has two pressure receiving surfaces 13A and 13B.
The circuit connecting these upper and lower cylinders 12 and 13 can either supply oil from the upper cylinder 12 to only one pressure-receiving surface of the lower cylinder 13, or simultaneously to both pressure-receiving surfaces, or supply oil to both pressure-receiving surfaces. It is characterized by having a switching valve 14 that cuts off the supply to both sides.

This will be explained in detail below. FIG. 2 is a diagram showing an embodiment of the present invention, and shows the state immediately after the completion of powder filling and the start of the powder compacting process.

A push rod 22 is connected to the adjustment screw 2 on the upper ram 2.
It is fixed by 3. Upper ram 2 descends,
When the powder compression process starts, the push rod 2
2 is the upper piston rod 1 of the upper cylinder 12
21 and press it down. Oil in the upper cylinder 12 pushed out as the upper ram 2 descends is injected into the lower cylinder 13 via the switching valve 14.

When the switching valve is in the state shown in FIG.

Therefore, the lower piston rod 131 of the lower cylinder 13 is adjusted according to the amount of descent of the upper ram 2 according to the cross-sectional area (a1) of the upper cylinder 12 and the cross-sectional area of the pressure receiving surfaces 12A and 13B of the lower cylinder (b1+b2).
The amount of movement is necessarily determined.

The lower piston rod 131 is fixed to the lower ram 7, and the lower ram 7 is connected to the die table 31, so as the upper ram 2 descends, the die table 3
The amount of movement of 1 will be determined.

In normal use, the cross-sectional areas (a1), (b1), and (b2) of each cylinder are the same.

Therefore, when the switching valve is set in the state shown in FIG.
1 will move.

In such powder compacting, even when powder compacting has a relatively high height in the compression direction, the upper punch and lower punch are pushed into the die 3 by the same amount to form the powder, resulting in a density difference between the upper and lower parts. It has extremely high molding stability.

Next, when the switching valve 14 is switched to the Y position, which is one position to the left from the state shown in FIG. The circuit to is disconnected. Therefore, the die table 31 does not move even when the upper ram 2 moves, and powder compression molding is performed only by the upper punch 5.

Such a molding method is advantageous for products that are relatively low in height or for products that require precision in the relative position of the lower punch 6 to the die 3.

Further, when the switching valve 14 is moved to the leftmost position (Z position), one pressure receiving surface 13 of the lower cylinder 13
B is closed, and only 13A is connected to the upper cylinder 12.

In this state, all the oil in the upper cylinder 12 is injected into the pressure receiving surface 13A of the lower cylinder 13, and the ratio of the travel distances of the upper ram 2 and lower ram 7 to the cross-sectional areas (a1) and (b1) is decide.

Usually, by setting (a1)=(b1), the amount of movement of the upper ram and the lower ram 7 is made the same.

In such powder compaction, a stopper is attached to the die table 31, compression is first performed using only the lower punch 6, and then the die table 31 is stopped moving by the stopper.
It is used in two-stage compression in which compression is performed using only the upper punch 5.

According to this method, the powder compact has a considerably high height, and the die table 31 and the lower punch 6
It can be easily molded even if the relative positional accuracy is required.

As described above, in the present invention, in various powder molding operations, three
It is possible to perform various types of powder compaction, and in powder compaction at the X position in FIG. It is possible to keep it constant. Furthermore, other powder molding methods, such as the two-stage compression molding method and the molding method with a fixed die table, do not require any special adjustment and can be switched only by switching the switching valve 14, and are not only extremely easy to work with, but also have excellent workability. , molding stability is also high.

Although the powder compacting apparatus of the present invention controls the relative movement of the upper punch, die, and lower punch during powder compression molding, processes other than the powder compacting process, such as powder filling and green compact removal, are performed in the same manner as conventional methods. It is controlled by conventional means used in mechanical and hydraulic forming equipment.

Therefore, by providing a solenoid valve 18 that closes the upper cylinder 12 and oil tank 19 at the start of the powder compression process and opens at the end of the powder compression process, the operation timing of the upper cylinder 12 can be adjusted and stabilized, and the upper cylinder A relief valve 17 is arranged between the oil pump and the oil pump to ensure safety in the event that abnormally high pressure occurs.

Furthermore, in the present invention, although it is most commonly used to make the cross-sectional areas (a1), (b1), and (b2) of the upper cylinder and lower cylinder the same, special powder molding is In the case of a powder compacting device whose conditions are limited, (a1), (b1), and (b2) can be selected depending on the conditions.

Further, it goes without saying that the lower cylinder may be attached to any position on the lower ram and may be fixed to the die table.

As described above, the powder compacting apparatus of the present invention can not only handle various types of powder compaction simply by switching the switching valve, but also maintain stable compaction in any powder compaction. By attaching a lower cylinder to the die table, a large area on the die table can be used, resulting in extremely high productivity.

[Brief explanation of drawings]

FIG. 1 is a conventional powder molding apparatus, FIG. 2 is a powder molding apparatus according to the present invention, and FIG. 3 is an enlarged view of the main part of FIG. 2. Explanation of numbers, 2...Top ram, 3...Die, 5...
...Upper punch, 6...Lower punch, 7...Lower ram, 8
...Cylinder, 31...Die table, 12...
Upper cylinder, 13...Lower cylinder, 13A...
...Pressure receiving surface, 13B...Pressure receiving surface, 14...Switching valve,
17... Relief valve, 18... Solenoid valve, 19...
oil tank.

Claims (1)

[Claims] 1. At least an upper punch 5, a die 3, and a lower punch 6.
During powder compaction, the upper punch 5,
In a powder compacting device that controls the relative operation of the die 3 and the lower punch 6, the upper ram 2 that fixes the upper punch 5 is provided with a push rod 22 that pushes the upper piston rod 121 of the upper cylinder 12, and fixes the die 3. The lower piston rod 131 of the lower cylinder 13 is fixed to the lower ram 7 or the die table 31, and the lower cylinder 13 has two pressure receiving surfaces 13A,
13B, and these upper and lower cylinders 12, 13
The circuit connecting the upper cylinder 12 is configured to supply oil from the upper cylinder 12 to only one pressure receiving surface of the lower cylinder 13, to both pressure receiving surfaces simultaneously, or to disconnect the supply to both pressure receiving surfaces. 1. A powder compacting device characterized by having a switching valve 14 for switching. 2. The powder compacting apparatus according to claim 1, wherein the cross-sectional area of the upper cylinder 12 and the cross-sectional area of the two pressure receiving surfaces of the lower cylinder 13 are equal. 3. The powder compacting apparatus according to claim 1, wherein the lower ram 7 is formed by fixing a lower piston rod 131 of the lower cylinder 13 and a filling piston rod 91 of the filling cylinder 9. 4. The powder compacting apparatus according to claim 1, wherein the upper cylinder 12 is connected to an oil tank via a solenoid valve 18 that closes when compacting starts and opens when compacting ends. 5. The powder compacting apparatus according to claim 1, wherein the upper cylinder 12 is connected to an oil tank 19 via a relief valve 17.