JPS6229160B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a die control device in a powder compacting press.

Conventionally, as a method of powder compaction, a spring or an air cylinder or the like is used to apply a pulling force that counters the weight of a vertically movable member consisting of a die plate and an extrusion plate of a die set, and the weight of a lower ram movable member on the press body side. Due to the frictional force generated between the powder and the inner wall of the die due to compression and compaction of the upper part as the upper punch is inserted into the die, the die is lowered by half of the compression stroke of the upper punch, so-called lower punch fixation. Floating die presses, in which the die floats, are in practical use.

However, in the press with the above-mentioned formation, when the upper punch is inserted into the die, the fine particles of the powder raw material to be handled are bitten into the gaps that occur at the contact areas between the upper punch side surface and the die inner surface, and the lower punch side surface and the die inner surface. This causes the floating amount of the die to no longer behave like a logical floating die. That is, the compression stroke from the top and the compression stroke from the bottom are different, resulting in uncertain movement, resulting in problems such as the density of the compression molded molded product being different between the upper and lower parts.

Therefore, the sintered product shrinks in proportion to the compacted powder density during powder compaction, making it impossible to obtain the expected dimensions and strength and resulting in large dimensional errors. The problem was that there was no guarantee.

On the other hand, when molding irregularly shaped products such as cutting tools such as ultra-hard throw-away chips, pressure is applied from the top by the upper punch, the die floats and the pressure stroke is applied from the bottom by the lower punch, and the arbitrary pressure stroke of the die is applied. If stopping at the height can be controlled freely from the outside, the dimensions of the molded product and the density of each part will be
It should be possible to form into a specified state and the dimensional accuracy after sintering should be uniform, but there are disturbance factors such as the powder raw material being caught between the die and punch, and the initial flow of the powder during the powder compression process. However, as the compression process progresses, the powder solidifies and becomes difficult to flow, making it difficult to obtain the desired density in each part.

Therefore, the reality is that with conventional equipment, the product dimensions of molded products tend to vary, making it difficult to obtain highly accurate molded products.

The present invention has been made in view of the above-mentioned circumstances, and particularly improves the problems that have arisen in the past, and allows the movement of the die to be controlled freely and reliably from the outside to achieve stable and high precision. The present invention provides a die control device for a powder molding press configured to obtain a product.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First, the press body is a floating die press equipped with a pressure mechanism and an extrusion mechanism, and is a general mechanism of a powder molding press equipped with a lower ram stopping device, so a description thereof will be omitted.

In the drawings, FIG. 1 shows a die set, and is an explanatory diagram showing a state in which powder 10 is filled and pressing is started.

A lower pressure plate 2 is integrally attached to the lower part of the press upper ram 1 with bolts or the like, and this lower pressure plate 2 has a T-shaped joint ( Up)
3 is provided.

In addition, a lower ram 21 is provided at the upper part of the lower press ram 21.
and the lower lower pressure plate 2 which is a lateral member integrally with the lower pressure plate 2.
0 and T-type joints (lower) 19 are provided.

The die set is inserted into the press upper ram 1 and the press lower ram 21 from the front through the T-shaped joint (upper) 3 and the T-shaped joint (lower) 19, and is connected by fitting. It is fixed to the bolster 15 by bolting or the like.

Further, a plurality of guide rods 8 are embedded in the die plate 9 in an upright manner, and the upper punch plate 5 is fitted into the guide rods 8 so as to be vertically slidable, so that the upper punch 7 can enter and exit the die 11. ing.

On the other hand, a lower punch 12 is attached to the die set fixing plate 14, the upper part of which is fitted with the die 11, and guided by a plurality of rods 16 so that the die can be lowered.

The lower part of the rod 16 is an extrusion plate 17.
The die plate 9 is integrally attached to the die plate 9, and is configured to be movable up and down.

Therefore, the upper punch plate 5 is connected to the upper press ram 1 by a T-shaped joint (upper) 3, and the extrusion plate 17 is connected to the lower press ram 21 by a T-shaped joint (lower).
19, the upper ram 1 performs compaction operation, and upon completion of compaction, the lower ram 21 (not shown) is pulled down by an extrusion cam, and the molded product is transferred to the die. Extrusion is completed when the plate 9 descends to the upper end surface of the lower punch 12.

Hydraulic cylinders 22 are provided on the left and right sides (not shown) of the lower pressure plate 2 of the upper ram 1, a piston 23 and a rod 24 extend downward, and a screw 25 is fitted at the lower end so that the length can be adjusted. has been done.
The lower end of the screw 25 is in contact with the upper end surface of the rack 26. Here, before the upper punch 1 reaches the top surface of the die, there is a gap between the screw 25 and the rack 26, and as the upper punch 7 descends, the gap becomes smaller, and as shown in FIG. 1, the compression operation is started. It is what it is.

On both sides of the lower lower pressure plate 20, a swinging lever 27 is rotatably supported by a pin 28 on a bracket portion 20a, and on one side of the swinging lever 27, a sector gear 27a that meshes with a rack 26 is formed. On the other side, a roller 30 is pivotally supported by a pin 29.

Further, a cam 31 is rotatably supported by a pin 32 on the bracket portion of the press frame, and is prevented from rotating by a cam positioning bolt 33 provided on the press frame. In the figure, reference numerals 34a and 34b are tension springs which apply a returning force to the cam 31 and the rack 26. Furthermore, reference numerals 4 and 18 are fitting groove members that connect the T-shaped joint (upper) 3 and the T-shaped joint (lower) 19, respectively. 6 and 13 are clamp rings fixed to the upper punch 7 and the lower punch 12. Furthermore, 50 is the lower pressure plate 20
The lower press ram 21 is held in place via a rod 51.

Next, the operation of the apparatus configured as described above will be explained. Figure 1 shows the compression start position, where the cam 31 is vertical and θ=0.
In this case, the lowering stroke of the upper ram 1 attempts to push down the rack 26 and rotate the sector gear 27a of the swing lever 27, but the other roller 30 of the swing lever 27 Cam 31 with bolt 33 attached to the frame
The lower press ram 21 is prevented from rotating.
The lower pressure plate 20 is pushed down by the same amount as the stroke of the upper ram 1, and the powder 10 is only compressed from below.

Here, during the compression stroke process, the lower punch 12
When the frictional force generated on the inner wall of the die by the compacted powder exceeds the value set by the relief valve 42 installed in the hydraulic line, the pressure oil is released and returned to the tank 38. It plays the role of a safety device.

Next, the cam 31 is set at θ=45° so that the cam 31 and the roller 30 are not in contact with each other at the pressure start point, and when the pressure starts, the lowering stroke of the upper ram 1 is oscillating. Only by rotating the movable lever 27, the lower ram 21 and the lower pressure plate 20 are not pushed down. That is, the consecutively arranged dies are not pushed down by the action of the hydraulic cylinder 22, and the dies are not pushed down by the support cylinder 50 of the lower pressure plate 20.
It is supported by the supporting force of , and does not fall. Therefore, the powder 10 was subjected to only compression force from above.

Also, if the cam 31 is set to an appropriate θ, the second
As shown in the figure, the amount of descent of upper ram 1 and lower ram 2
1, that is, the amount by which the die is pushed down becomes one half, and the die is lowered at one half the speed of the movement of the upper ram 1, and the cylinder 51 is moved so that the lower ram 21 is held appropriately. Because it is installed, the movement of the die can be set positively.

What is particularly important is the frictional force between the upper and lower punches 7, 12 and the inner wall of the die 11, in other words, even if there is a disturbance factor, the operation of the die can be controlled arbitrarily, so the vertical density of the compact can be controlled as desired. It can be done.

In the forming method of this press as a floating die, the movement of the die can be controlled freely from the outside, rather than floating the die due to the frictional force between the green compact and the inner wall of the die due to the pressure applied by the upper punch 7.

Next, the operation of the hydraulic cylinder 22 provided on the lower pressure plate 2 of the upper ram 1, that is, the die control cylinder, will be explained.

first. Compressed air (5 kg/cm ² G) from an air source 35 is adjusted to an appropriate pressure, for example, 3 to 4 kg/cm ² G, by a pressure reducing valve 36 and is supplied to the upper part of a two-layer air/oil tank 38. . From here, the oil passes through the check valve 41 and enters the die control cylinder 2.
2, and then the air-driven hydraulic pump 39 rotates to pump oil up to the set discharge pressure.

When the above-mentioned discharge pressure reaches a predetermined pressure, the driving air pressure and the discharge pressure are balanced by the amplified pressure, and the piston 23 is stopped.
5 comes into contact with the rack 26 and pushes the lower press ram 21 downward.

At this time, since a predetermined pressure is applied to the cylinder in advance, when the upper punch 7 reaches point A,
The lower press rams 20, 21 and the die plate 9 connected thereto are positively pushed down. That is, in cooperation with the die plate 9, control of the die can be ensured.

On the other hand, a hydraulic cylinder 50, a piston, and a piston rod 51 are provided at symmetrical positions below the lower pressure plate 20 of the lower ram 21, and an air source 35
Pressure reducing valve 43, air/oil double layer tank 45
Pressure is applied to the tank 45, and oil passes through the check valve 46 from the lower part of the tank 45, lifts the piston 51 from the lower surface of the cylinder 50, and supports the weight of the lower ram 21.

Therefore, as the upper ram 1 descends, the lower pressure plate 20 of the lower ram 21 is pressed down by the die control cylinder 22, piston 23, and screw 25, but the pressure of the relief valve 47 is lower than the hydraulic output of the upper ram 1. is set, the movement of the die plate 9 (die 11) is controlled.

Furthermore, the lower ram 21 is pushed down by adjusting the cam 31, and at this time, the lower ram 21 is designed to retreat downward while maintaining the desired supporting force.

The above-mentioned supporting force can be controlled from the outside by adjusting the relief valve 47, so even if the frictional force between the upper punch 7 and the die 11 or the frictional force between the powder 10 and the inner wall of the die 11 changes, the die The operating speed and stroke of plate 9 remain unchanged.
By setting θ of the cam 31, the die control can be arbitrarily controlled. The compression process shown in FIGS. 1 and 2 will now be explained in more detail with reference to FIG. 3. In FIG. 3, P indicates the operating curve of the upper punch, and Q indicates the operating curve of the die.

First, the upper punch enters the die and begins compression. That is, this is the die control starting point A. Next, when the upper punch is further lowered, the rod 24 swings the swinging lever 27 via the rack 26 and presses the cam 31, and as a result, the lower lower pressure plate 20 also moves down. Start. Thereafter, the upper punch and the die move down in conjunction with each other until the compression is completed at point _B1 . In this embodiment, the pin 28 of the swing lever 27
If the length from the roller pin 29 to the roller pin 29 is R, and the length from the pin 28 to the easy contact 26a is R, then the die is 1/2 of the upper punch for the lowering distance of the upper punch.
Only the stroke moves down in conjunction with each other, so that the packed powder in the compression process always receives the downward pressing force from the upper punch and the upward pressing force from the lower punch at the same time.

When the compression is completed in this way, the upper ram 1 rises, and the lower ram 21 moves down one step further. In conjunction with the lowering of the lower ram 21, the die plate 9 also lowers to a position where the green compact can be freely taken out, completing the knockout of the molded product.

In addition, H ₀ ; Powder filling depth, h; Molded product height, E;
Extrusion stroke, TC; total compression stroke, U _c
1 , U _c2 ; Upper pressure stroke, L _c1 , L _c2 ; Lower pressure stroke, B ₁ point is the die control end point, and if the die control stroke is zero,
That is, U _c = TC, L _c = 0 or B ₂ points are U _c1 = L _c1 , that is, in the state of positive floating die, U _c1 = L _c1 =
1/2TCB ₃ points indicate the state of U _c2 = 2L _c2 B ₄ points indicate U _c
=0, L _c =T _c .

FIG. 4 is an explanatory diagram showing a die control device showing another embodiment of the present invention, in which the upper ram 1
One side arm of an L-shaped swing lever 27' is in contact with the lower end of a piston rod 24 of a hydraulic cylinder 22 provided on the lower pressure plate 2 via a length-adjustable screw 25.

Note that the rest is the same as the embodiment of the present invention, so the explanation will be omitted.

As explained in detail above, according to the die control device for powder press according to the present invention,
With a simple structure, the product dimensions of the molded product can be stabilized and the occurrence of defective products can be eliminated.

In addition, the upper punch applies pressure from the top, the lower punch applies pressure from the bottom stroke, and any stoppage of the die can be freely controlled from the outside, so the dimensions of the molded product and the density of each part can be adjusted to the desired state. It can be molded and has uniform dimensional accuracy after sintering, resulting in a highly accurate product.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the main parts of the die control device according to the present invention, and is an explanatory diagram of the compression operation starting state, FIG. 2 is an explanatory diagram of the operating state of the die control device according to the present invention, and FIG. It is a graph showing the operating curve of the upper punch and die. FIG. 4 is a schematic diagram of a die control device showing another embodiment of the present invention. 1... Upper ram, 2... Upper lower pressure plate, 3...
...T-type joint (top), 5...Top punch plate, 7
...Upper punch, 8...Guide rod, 9...Die plate, 10...Powder, 11...Dice, 12
... lower punch, 14 ... die set fixing plate, 15 ... bolster, 16 ... rod, 17 ...
...Extrusion plate, 19...T-type joint (bottom), 20
...Lower lower pressure plate, 21...Lower ram, 22...
...Cylinder, 23...Piston, 24...Rod, 25...Screw, 26...Rack, 26a...
Swinging lever contact, 27... Swinging lever, 30...
Roller, 31...Cam, 33...Bolt, 35...
... Air source, 36, 43 ... Pressure reducing valve, 38, 45
...Two-layer tank, 41, 46...Check valve, 39...
...Hydraulic pressure pump, 42,47...Relief valve, 48...Control valve, 37,40,
44,49...Pressure gauge.

Claims (1)

[Claims] 1. In a floating die press, an upper ram, a lower pressure plate, a hydraulic cylinder provided on the upper ram, and a lower end of a piston can be brought into easy contact with each other, and a sector gear that meshes with the rack can be connected to the upper ram and the lower pressure plate. It consists of a swinging lever with a swing lever, and a cam installed on the press frame side where the tip roller of the swinging lever comes in contact with. A die control device for a powder forming press, characterized in that it can move by the same amount as the amount of descent. 2. In the device that preloads the hydraulic cylinder of the upper ram in advance, adjust the pressure of the air source to an appropriate pressure, fill the die control cylinder via the check valve, and use the hydraulic pump to supply oil at the set discharge pressure. 2. A die control device for a powder forming press according to claim 1, further comprising a hydraulic pressure increase device configured to pump a powder. 3. The die in the powder forming press according to claim 1, wherein the hydraulic cylinder of the lower ram sets a desired supporting force of the lower ram against the die control force as the upper ram descends. control device.