JPS6364279B2 - - 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 7,
The lower ram 7 is connected to a filling cylinder 9.

To fill the powder, pressurized fluid is injected into the filling cylinder 9, the lower ram 7 and the die table 31 are pushed up,
A space formed by the die 3, core rod 4, and lower punch 6 is filled with powder by a feeder that reciprocates on a die table 31.

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, if the length in the compression direction is long, the upper and lower 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 movement of the piston rod 81 is controlled and the amount by which the die table 31 is pushed is adjusted. For example, when the relief valve 17 is in an almost open state, the piston rod 81 will not push the die table 31;
When closed, the piston rod 81 is almost fixed,
The amount of descent of the upper ram 2 and the amount of descent of the die table 31 are 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. .

Controlling powder compaction using such hydraulic cylinders is more difficult than mechanical control using cams, etc.
Even if an abnormally high compression state occurs, pressure can be released, so even in various types of molding equipment such as mechanical and hydraulic, the upper punch 5, lower punch 6, and die 3 are used during powder compression molding. It was used for relative position control.

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, it is an object to obtain a powder compacting device that is stable in powder compaction and has excellent productivity such as workability. This embodiment of the invention is shown in FIGS. 2 and 3.

The gist of the present invention is that a push rod 22 that pushes a spool 122 is fixed to the upper ram 2 to which the upper punch 5 is fixed, and a push rod 22 that pushes the spool 122 is fixed to the lower ram 7 or the die table 31 connected to the die table 31 having the die 3. The lower piston rod 131 of the lower cylinder 13 is fixed, and the spool 122 is slidably fitted to the upper piston 121 of the upper cylinder 12, and opens and closes a valve seat 127 that communicates the upper cylinder chamber 124 with the oil tank 19. It has a valve part 126, and the lower cylinder 13 has two
The circuit connecting these upper and lower cylinders 12 and 13 has two pressure receiving surfaces 13A and 13B, and the oil in the upper cylinder 12 is supplied to only one pressure receiving surface of the lower cylinder 13, or to both pressure receiving surfaces. This powder compacting apparatus is characterized by having a switching valve 14 for supplying powder to both pressure surfaces at the same time or cutting off supply to both pressure receiving surfaces.

This will be explained in detail below. FIG. 2 is a diagram showing one embodiment of the present invention, and FIG. 3 is an enlarged view of the main part of FIG.

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,
Immediately before the start of the powder compression process, the push rod 22 pushes the spool 122 of the upper cylinder 12, and the valve portion 126 at the tip of the spool 122 presses against the valve seat 127 provided on the upper piston 121.

As a result, the valve seat 127 that communicates the upper cylinder chamber 124 with the oil tank 19 is closed. When the upper ram 2 further descends and the powder compression process starts, the oil in the upper cylinder 12 pushed out as the upper ram 2 descends is injected into the lower cylinder 13 via the spout 128 and the switching valve 14. be done.

When the switching valve 14 is in the state shown in FIGS. 2 and 3 and in the X position, oil in the upper cylinder 12 is injected into both of the two pressure receiving surfaces 13A and 13B of the lower cylinder 13.

Therefore, depending on the sum (b1+b2) of the cross-sectional area (a1) of the upper cylinder 12 and the cross-sectional area (b1), (b2) of the pressure receiving surfaces 12A, 13B of the lower cylinder 13, the lowering amount of the upper ram 2 The amount of movement of the lower piston rod 131 of the lower cylinder 13 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 plate 31, so the die table 3 moves as the upper ram 2 descends.
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,
Since the lower punch is pressed in the same amount to form the mold, there is no difference in density between the upper and lower parts, resulting in 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, even when the upper ram 2 moves, the die table 31 does not move and the upper punch 5 moves.
Powder compression molding is carried out using a chisel.

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 moving distances of the upper ram 2 and lower ram 7 is determined with respect to the cross-sectional areas (a1) and (b1). do.

Usually, by setting (a1)=(b1), the amount of movement of the upper ram 2 and the lower ram 7 is made the same.

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

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.

Further, in the present invention, just before the powder compression molding step, the valve portion 126 and the valve seat 127 of the spool 122 are closed so that the oil tank 19 and the upper cylinder 12 are disconnected, and after the powder molding process, the valve portion 126 and the valve seat 127 are closed. As the upper ram 2 rises, the spool 122 also rises, the valve seat 127 opens, and oil is injected into the upper cylinder 12 from the oil tank 19 via the upper cylinder chamber 124 and the valve seat 127. .

Therefore, the operation of the upper cylinder 12 is automatically controlled in accordance with the upward and downward movement of the upper ram 2, and there is no deviation in the operation timing or delay in response of the upper cylinder.

As described above, in the present invention, in various powder molding operations, three
It is possible to carry out various types of powder compaction, and in the case of powder compaction at the X position in Fig. 2, which is normal powder compaction, the movement distance ratio of the upper ram 2 and die table 31 can always be kept stable and constant. It is possible to maintain
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.

Furthermore, since the operation of the upper cylinder is controlled by the upward and downward movement of the upper ram, there is no shift in operation timing and excellent responsiveness is achieved.

Note that a relief valve 17 is provided between the spout 128 of the upper cylinder 12 and the oil tank 19 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.

Furthermore, it goes without saying that the lower cylinder may be fixed at any position on the lower ram, and may also 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 parts of FIG. Explanation of numbers, 2...Top ram, 3...Die, 5...
...Upper punch, 6...Lower punch, 7...Lower ram, 8
...Cylinder, 31...Die table, 122...
... Spool, 12 ... Upper cylinder, 13 ... Lower cylinder, 13A ... Pressure receiving surface, 13B ... Pressure receiving surface, 14 ... Switching valve, 17 ... Relief valve, 19
...Oil tank, 127...Valve seat.

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 a die 3 and a lower punch 6, a push rod 22 that pushes a spool 122 is fixed to the upper ram 2 to which the upper punch 5 is fixed, and is coupled to a die table 31 having a 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 spool 122 is slidably fitted into the upper piston 121 of the upper cylinder 12, and the upper cylinder chamber 124 is oil-filled. It has a valve part 126 that opens and closes a valve seat 127 that communicates with the tank 19, and the lower cylinder 13 has two pressure receiving surfaces 13A, 13.
B, and in the circuit connecting these upper and lower cylinders 12 and 13, the oil of the upper cylinder 12 is supplied to only one pressure receiving surface of the lower cylinder 13, or to both pressure receiving surfaces simultaneously. Or switching valve 1 to cut off the supply to both pressure receiving surfaces.
4. A powder compacting device characterized by having: 2. The first aspect of claim 1, wherein the cross-sectional area of the upper cylinder 12 and the cross-sectional area of the pressure receiving surfaces 13A and 13B of the lower cylinder 13 are equal.
Powder compaction equipment as described in section. 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 of the filling cylinder 9. 4 The spool 122 is moved between the valve portion 126 and the valve seat 12 of the upper piston 121 by the lowering of the upper ram 2.
7 to operate the upper piston 121, and at the same time, the oil tank 19 and the upper cylinder chamber 124
At the same time, as the upper ram 2 rises, the valve part 1
26 and the valve seat 127 are separated from each other, and the oil tank 19 and the upper cylinder chamber 124 are communicated with each other. 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.