JPH0547611Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to a booster ram type mold clamping device, and particularly to a technique for shortening the mold clamping cycle.

(Background Art) Traditionally, as a type of direct pressure type mold clamping device in injection molding machines, die casting machines, etc., a mold clamping device has been used to slide inside the main cylinder chamber so as to partition the main cylinder chamber into a mold clamping cylinder chamber and a mold opening cylinder chamber. A booster ram cylinder chamber is formed in the fitted main ram for moving the movable platen toward and away from the fixed platen, and the booster ram is slidably inserted into the booster ram cylinder chamber. During the clamping operation, pressure oil is first supplied to the booster ram cylinder chamber through the booster ram to cause the movable platen to close the mold, and then pressure oil is supplied to the mold clamping cylinder chamber to perform the mold clamping operation. A so-called booster ram type mold clamping device is known.

In such a booster ram type mold clamping device, the mold clamping system quickly supplies and discharges hydraulic oil to the mold clamping cylinder chamber when the mold is opened and closed, thereby enabling high-speed opening and closing of the mold. A valve cylinder chamber is provided in communication with the cylinder chamber, and a prefill valve is slidably fitted into the valve cylinder chamber, and movement of the prefill valve causes the mold clamping cylinder chamber to connect to an external oil tank. It is also conventionally known to perform connection/disconnection control (communication control).

By the way, in a booster ram type mold clamping device equipped with such a pre-fill valve, the pre-fill valve is closed by supplying pressure oil to the drive cylinder chamber formed between the pre-fill valve and the inner wall of the valve cylinder. It is generally done to open the pre-fill valve, and for this purpose, when the pre-fill valve is closed prior to the mold clamping operation that supplies pressure oil into the mold clamping cylinder chamber, hydraulic oil is drained from the driving cylinder chamber. It has become necessary to discharge it.

In this type of conventional booster ram type mold clamping device, the hydraulic oil discharge passage from the drive cylinder chamber for opening the prefill valve is directly connected to the external oil tank via the valve means. When the pre-fill valve is closed, the hydraulic oil discharged from the drive cylinder chamber is allowed to directly flow into the external oil tank.

For this reason, in this type of conventional booster ram type mold clamping device, when the prefill valve is closed, atmospheric pressure is applied to the drive cylinder chamber in response to the movement of the prefill valve in the closing direction (closing operation). It is unavoidable that the same resistance will be applied when a considerable amount of pressure oil is supplied, which will hinder the closing operation of the prefill valve, prolonging the closing operation time of the prefill valve, and eventually damaging the mold. There was a problem when the tightening cycle became that long.

(Problem to be solved) The present invention was developed against the background of the above, and the problem to be solved is that when the prefill valve is closed, it is difficult to open the prefill valve. The hydraulic oil from the drive cylinder chamber for actuation can be discharged more quickly than before, and the prefill valve caused by the hydraulic oil in the drive cylinder chamber for opening the prefill valve can be discharged more quickly than before. It is an object of the present invention to provide a booster ram type mold clamping device that reduces the resistance to the closing operation of the valve, thereby shortening the closing operation time of the prefill valve and, by extension, shortening the entire mold clamping cycle.

(Solution Means) In order to solve this problem, in the present invention, as described above, the main cylinder chamber can be slid into the mold clamping cylinder chamber and the mold opening cylinder chamber so as to partition the main cylinder chamber into the mold opening cylinder chamber. A booster ram cylinder chamber is formed in the main ram fitted to the main ram for moving the movable platen toward and away from the fixed platen, and the booster ram is slidably inserted into the booster ram cylinder chamber. , a pre-fill valve for controlling the communication state of the mold clamping cylinder chamber with an external oil tank is slidably fitted in a valve cylinder chamber provided in communication with the mold clamping cylinder chamber of the main cylinder chamber, and the mold The opening operation of the prefill valve in the direction of communicating the tightening cylinder chamber and the external oil tank is performed by introducing pressure oil into a drive cylinder chamber formed between the prefill valve and the inner wall of the valve cylinder. In the booster ram type mold clamping device, the driving cylinder chamber is connected to an oil passage communicating the clamping cylinder chamber and an external oil tank via a predetermined valve means, and the clamping cylinder chamber The drive cylinder chamber can be brought into communication with the oil passage when the pre-fill valve is closed in the direction of cutting off communication between the prefill valve and the external oil tank.

(Function) The closing operation of the prefill valve in the booster ram type mold clamping device is performed when the mold closing operation is completed. The amount of hydraulic oil supplied from the tank is still not sufficient, and the mold clamping cylinder chamber and furthermore, the oil passage connecting the external oil tank to the mold clamping cylinder chamber are still in a negative pressure state. Therefore, as in the present invention, if the drive cylinder chamber for opening the pre-fill valve is communicated with the oil passage when the pre-fill valve is closed, the hydraulic oil in the drive cylinder chamber can be removed. is not simply discharged passively by the contraction force of the drive cylinder chamber due to the movement of the pre-fill valve, but is also actively discharged by the suction action of the negative pressure in the oil passage.
Accordingly, the discharge of the hydraulic oil from the drive cylinder chamber is promoted, and the resistance to the closing operation of the pre-fill valve due to the hydraulic oil in the drive cylinder chamber is reduced, which reduces the closing operation time of the pre-fill valve and ultimately the mold clamping cycle. will be shortened.

(Example) Hereinafter, in order to clarify the present invention more specifically, one example thereof will be described in detail based on the drawings.

First, in FIG. 1, 10 is the main cylinder, which is the rear (left side in the figure) valve cylinder 1.
4, and an outward flange portion 16 is integrally provided at the front end thereof. A plurality of tie bars 18 are disposed with each end supported by the flange portion 16 of the main cylinder 10.

At the other end of the tie bar 18, a fixed plate (not shown) for mounting a fixed mold is fixedly installed, and between the fixed plate and the main cylinder 10, the tie bar 18 A movable platen 20 is disposed on which a movable mold is mounted while being guided in a direction. A main ram 22 is fixed to the movable platen 20 at its front end.

The main ram 22 has a large diameter section 24 at a predetermined length at the rear end, and can slide in the front and back direction on the inner surface of the main cylinder chamber, which is the inner space of the main cylinder 10, in the large diameter section 24. At the same time, at the small diameter portion in front of the large diameter portion 24, it is fitted to the inward flange portion 26 at the front end of the main cylinder 10 so as to be slidable in the front-rear direction. As a result, the main cylinder chamber in the main cylinder 10 becomes
It is partitioned into a mold clamping cylinder chamber 28 on the rear side of the large diameter section 24 and a mold opening cylinder chamber 30 on the front side of the large diameter section 24.

On the other hand, a cylindrical pre-filled valve 32 with a bottom is fitted into a valve cylinder chamber, which is an inner space of the valve cylinder 14, so as to be slidable in the front-rear direction and open rearward. Through this pre-fill valve 32, the valve cylinder chamber is connected to an inner cylinder chamber 34 which communicates with the mold clamping cylinder chamber 28, and an inner cylinder chamber 34 for moving the pre-fill valve 32 rearward by introducing pressure oil. It is partitioned into an outer cylinder chamber 36.

More specifically, the inside of the valve cylinder has a stepped cylindrical shape with a larger diameter on the rear side;
An outward flange portion 38 is formed at the opening edge of the pre-fill valve 32 . The pre-filled valve 32 is fitted on the outer circumferential surface of the bottomed cylindrical portion and the outer circumferential surface of the outward flange portion 38 into the small diameter portion and the large diameter portion of the valve cylinder chamber, respectively, so as to be slidable in the front-rear direction. , whereby the valve cylinder chamber is integrated with the inner space of the pre-filled valve 32 into the inner cylinder chamber 34.
and an outer cylinder chamber 36 formed between the prefill valve 32 and the inner wall of the valve cylinder chamber, in which the prefill valve 32 can be moved rearward by introducing pressure oil. Here, a through hole 40 is formed in the bottom wall of the bottomed cylindrical portion of the pre-filled valve 32, so that the clamping cylinder chamber 28 of the main cylinder chamber and the inner cylinder chamber 34 of the valve cylinder chamber are always in communication. They are forced to do so.

Note that the rear end opening of the valve cylinder 14 is fluid-tightly closed by a closing member 41, and between this closing member 41 and the bottom wall of the bottomed cylindrical portion of the pre-filled valve 32, the pre-filled valve 32 is closed. A compression coil spring 42 is provided that always urges the front side forward.

Here, the main ram 22 has a booster ram cylinder chamber 44 which is open at the rear end surface and has a significantly smaller cross-sectional area than the mold clamping cylinder chamber 28.
is formed concentrically with the main ram 22. A longitudinally cylindrical booster ram 46 is fitted into the booster ram cylinder chamber 44 so as to be slidable in the front-rear direction with respect to the booster ram cylinder chamber 44 at its front end. Note that this booster ram 46 is connected to the closing member 4.
1. It is disposed through the compression coil spring 42 and the through hole 40 in the bottom wall of the pre-filled valve 32, and is fixedly fixed to the closing member 41 in a fluid-tight manner.

By the way, the valve cylinder 14 is located at a portion adjacent to the front side of the outer cylinder chamber 36, and is communicated with the mold clamping cylinder chamber 28 by moving the pre-filled valve 32 to the front side. By moving to the side, the mold clamping cylinder chamber 28
A communication hole 48 is formed that is blocked from the air. An external oil tank 52 is connected to this communication hole 48 via an oil passage 50.
Based on the movement of the pre-fill valve 32 in the longitudinal direction, the mold clamping cylinder chamber 28 is brought into step contact with an external oil tank 52 via an oil passage 50.

On the other hand, an electromagnetic switching valve 56 is connected via an oil passage 54 to the outer cylinder chamber 36 in the valve cylinder chamber that moves the prefill valve 32 rearward by introducing the pressure oil. Depending on the switching operation of the valve 56, the outer cylinder chamber 3
Pressure oil supply oil passage 5 for supplying pressure oil into 6
8 and a discharge oil passage 60 for discharging the hydraulic oil in the outer cylinder chamber 36 are alternatively connected to the outer cylinder chamber 36. and,
Here, a discharge oil passage 60 for discharging the hydraulic oil in the outer cylinder chamber 36 is connected to the outer oil tank 5.
2 and the communication hole 48, and in turn, the external oil tank 52 and the mold clamping cylinder chamber 28 are connected to the oil passage 50,
It is forced to connect.

Next, the operation of such a mold clamping device will be explained.

First, as shown in Fig. 1, the main ram 2
2 is pulled rearward, the movable platen 20 is held at the mold opening position, the prefill valve 32 is held at the forward end position, and the communication hole 48 is blocked from the mold clamping cylinder 28. When a closing command is issued, pressure oil is supplied to the booster ram cylinder chamber 44 through the booster ram 46,
The main ram 22 is advanced at high speed, the movable platen 20 is brought close to the fixed platen at high speed, and the mold is closed at high speed. 56 , the prefill valve 32 is operated backward (opened) against the biasing force of the compression coil spring 42 , and the communication hole 48 and eventually the external oil tank 52 are connected to the mold clamping cylinder chamber 28 . Due to the negative pressure generated by the forward movement of the main ram 22, the external oil tank 52 is connected to the mold clamping cylinder chamber 28.
Hydraulic oil is sucked into and replenished. Under such high-speed mold closing operation, when the movable platen 20 reaches the mold closing speed switching position a predetermined distance ahead of the mold closing position, the amount of oil supplied to the booster ram cylinder chamber 44 is reduced, and the movable platen The mold closing speed of 20 is switched to low speed. In other words, a low-speed mold closing operation is performed.

When the molds are matched by the low-speed mold closing operation, the electromagnetic switching valve 56 is immediately switched, and the outer cylinder chamber 36 of the valve cylinder chamber is connected to the discharge oil passage 6.
0, the hydraulic pressure in the outer cylinder chamber 36 is released, the prefill valve 32 is moved forward (closed) by the biasing force of the compression coil spring 42, and the communication hole 48 is isolated from the mold clamping cylinder chamber 28. Ru.
In other words, the external oil tank 52 is connected to the mold clamping cylinder chamber 28.
It is cut off from.

When the external oil tank 52 is shut off from the mold clamping cylinder chamber 28 by the closing operation of the pre-fill valve 32, the oil flows through the port 62 to the inner cylinder chamber 34 of the valve cylinder chamber, and eventually to the mold clamping cylinder chamber 28 of the main cylinder chamber. Pressure oil is supplied to the main ram 2.
A clamping force is applied to 2, and the mold is compressed. Then, when a predetermined molding operation is performed under the clamping operation and a preset time has elapsed, the pressure in the mold clamping cylinder chamber 28 and the booster ram cylinder chamber 44 is released, while the electromagnetic switching valve 56 The prefill valve 34 is
is operated to open, and the mold clamping cylinder chamber 28 is opened to the oil passage 5.
0 to an external oil tank 52, and pressurized oil is supplied to the mold opening cylinder chamber 30 through a port 64, the main ram 22 is operated backward, and the mold is opened. When the movable platen 20 is moved back to the initial mold opening position by the mold opening operation, a series of mold clamping operations is completed.

Note that when the mold clamping operation is performed continuously, the prefill valve 32 is in the retracted position (open position) that communicates the mold clamping cylinder chamber 28 with the external oil tank 52 in the mold open state of the mold. It will be retained.

By the way, in such a mold clamping device, as described above, the outer cylinder chamber 36 of the valve cylinder chamber in which the prefill valve 32 is opened is connected to the oil passage 5 when the prefill valve 32 is closed.
4. It is connected to an oil passage 50 that communicates the mold clamping cylinder chamber 28 (communication hole 48) with the external oil tank 52 through the electromagnetic switching valve 56 and the discharge oil passage 60, and the hydraulic oil in the outer cylinder chamber 36 is connected to the oil passage 50. 5
It will be discharged to 0.

On the other hand, as described above, the closing operation of the prefill valve 32 is performed when the mold closing operation is completed. The oil passage 50 communicating with the mold clamping cylinder chamber 28 is
It is still under negative pressure. Furthermore, if the external oil tank 52 is not an overhead tank, the inside of the oil passage 50 will be in a negative pressure state also due to the falling action of the hydraulic oil due to its own weight.

Therefore, the hydraulic oil in the outer cylinder chamber 36 of the valve cylinder chamber that performs the opening operation of the prefill valve 32 is simply passively discharged by the backward operation of the prefill valve 32 based on the biasing force of the compression coil spring 42. Not only is the hydraulic oil in the outer cylinder chamber 36 discharged to the outer oil tank 52, but it is also actively discharged due to the suction action of the negative pressure in the oil passage 50. The outer cylinder chamber 36
The hydraulic oil in the outer cylinder chamber 36 is discharged more quickly, and the resistance to the closing operation of the pre-fill valve 32 due to the hydraulic oil in the outer cylinder chamber 36 is reduced, which reduces the closing operation time of the pre-fill valve 32 and, ultimately, the mold clamping device. This means that the mold clamping cycle can be shortened.

Note that, as is clear from the above description, in this embodiment, the outer cylinder chamber 36 of the valve cylinder chamber
constitutes a driving cylinder chamber for opening the pre-fill valve 32, and also serves as a driving cylinder chamber for opening the pre-fill valve 32.
6 constitutes a valve means.

One embodiment of the present invention has been described in detail above, but
This is a literal illustration, and it goes without saying that the present invention is not limited to these specific examples, and can be implemented with various changes, modifications, improvements, etc., without departing from the spirit thereof. By the way.

(Effect of the invention) As explained above, in the present invention, when the prefill valve is closed, the drive cylinder chamber for opening the prefill valve is connected to the mold clamping cylinder chamber and the external oil tank. The hydraulic oil in the drive cylinder chamber is drained into the oil tank by connecting it to an oil tank that communicates with the cylinder.
Compared to the conventional booster ram type mold clamping device, there is an advantage that the closing operation time of the prefill valve can be shortened, and the mold clamping cycle can be effectively shortened.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of a booster ram type mold clamping device according to the present invention. 10...Main cylinder, 14...Valve cylinder, 20...Movable plate, 22...Main ram, 28...
Mold clamping cylinder chamber, 30... Mold opening cylinder chamber, 3
2... Pre-fill valve, 36... Outer cylinder chamber (driving cylinder chamber), 42... Compression coil spring,
44... Booster ram cylinder chamber, 46... Booster ram, 48 communication hole, 50... Oil passage, 52...
...External oil tank, 56...Solenoid switching valve (valve means).

Claims (1)

[Scope of Claim for Utility Model Registration] A movable platen slidably fitted into the main cylinder chamber so as to partition the main cylinder chamber into a mold-clamping cylinder chamber and a mold-opening cylinder chamber is brought close to the fixed platen.
A booster ram cylinder chamber is formed in the main ram for isolated movement, and the booster ram is slidably inserted into the booster ram cylinder chamber, and is provided in communication with the mold clamping cylinder chamber of the main cylinder chamber. A pre-filled valve that controls the state of communication between the mold clamping cylinder chamber and the external oil tank is slidably fitted into the valve cylinder chamber, and a pre-filled valve is slidably fitted in the valve cylinder chamber to control communication between the mold clamping cylinder chamber and the external oil tank. In a booster ram type mold clamping device, the prefill valve is opened by introducing pressure oil into a drive cylinder chamber formed between the prefill valve and the inner wall of the valve cylinder, wherein the drive cylinder The chamber is connected via a predetermined valve means to an oil passage that communicates the clamping cylinder chamber with an external oil tank, and the clamping cylinder chamber and the external oil tank are connected to each other through a predetermined valve means. A booster ram type mold clamping device, characterized in that the drive cylinder chamber can be brought into communication with the oil passage when a pre-fill valve is closed.