JPH07102579B2 - Molding machine clamping device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct pressure type mold clamping device which can be used in a molding machine such as an injection molding machine or a die casting machine.

[0002]

2. Description of the Related Art In order to reduce the hydraulic resistance of a mold clamping piston moving in a mold clamping cylinder and increase the mold opening / closing speed,
A disc valve that opens and closes the passage is provided around the rear part of the mold clamping ram so that the front and rear two oil chambers communicate with each other through a passage formed in the mold clamping piston and the rear oil chamber on the mold clamping side opens and closes the passage. A mold clamping device of a molding machine, which is provided by being fitted and provided with an oil chamber for valve operation at a fitting and inserting portion between the disc valve and the mold clamping ram, is already known from Japanese Patent Publication No. 56-24614.

In the above-mentioned conventional apparatus, a mold opening / closing piston and a mold opening cylinder are provided by extending at the rear part of the mold clamping ram and the mold clamping cylinder, respectively, and the valve opening oil chamber of the disc valve is provided through the mold opening / closing piston. And the oil chamber of the mold opening cylinder are in communication with each other, while the oil chamber of the fast-forwarding piston for mold closing inserted from the rear end of the mold opening cylinder and the valve closing oil chamber are in communication with each other. The communication is performed by forming a flow path in the mold clamping ram.

Further, in the above-mentioned conventional apparatus, the disc valve is opened by the pressure oil supplied to the valve opening oil chamber through the oil chamber of the mold opening cylinder, and the closing is performed through the oil chamber for closing the mold of the fast-forwarding piston to close the valve closing oil. The pressure oil supplied to the chamber is used to close the passage of the mold clamping piston by the disc valve, and after the process of high-speed mold closing by the rapid feed piston is completed, the pressure in the rear oil chamber of the mold clamping cylinder is increased to a large degree. It is done just before the mold clamping force is generated.

[0005]

One of the problems of such a conventional apparatus is that a mold clamping ram is provided with a hydraulic passage for opening and closing a valve, so that a conventional mold clamping ram is provided. Compared with this, it takes much labor and cost to process the mold clamping ram, and the drilling process becomes more difficult as the stroke of the mold clamping ram becomes longer, so that it is difficult to employ it in a large mold clamping device.

Another problem is that the disk valve is closed because the disk valve closes the passage of the mold clamping piston by using a part of the hydraulic pressure supplied to the rapid-feed cylinder for high-speed mold closing. This is because it cannot be opened and closed independently.

Molding of synthetic resin includes compression molding in which the resin filled in the mold cavity is compressed.
There is also molding using a mold in which a spring member that repels in the mold clamping direction is incorporated in order to precede the mold release of the runner.

In the compression molding by the above conventional apparatus, in order to compress the resin in the mold, the disk valve is closed immediately before the mold is closed to close the passage of the mold clamping piston, and the rear oil chamber of the mold clamping cylinder is closed. It is necessary to supply pressure oil to.

In ordinary injection molding, it is sufficient that at least the closing of the mold clamping piston by the disc valve is completed before the injection and filling of the resin, but in compression molding, the resin is compressed by a slight speed advance of the mold clamping ram. Because it is desired, the timing of its closure is difficult,
Often, the compression process is entered before the valve is completely closed. As a result, the resin is not compressed by the hydraulic pressure in the rear oil chamber of the mold clamping cylinder, and a molded product with high molding accuracy cannot be obtained.

Further, in molding using a mold incorporating a release spring member, it is difficult to close the mold due to the spring pressure on the mold side at a low pressure and a low speed immediately before the mold is closed before the valve is closed. When the mold opening is started, there is a problem that the cavity mold is not opened smoothly due to the repulsive force of the spring member, and the molded product is damaged at the time of releasing the mold.

The present invention has been conceived in order to solve the problems of the conventional mold clamping device incorporating the disc valve, and its object is to use a pipe for the hydraulic passage in the mold clamping ram. Provides a new mold clamping device for a molding machine that can be easily configured and allows independent opening and closing of the disc valve by making the hydraulic path independent, which can be easily used for special molding such as compression molding. To do.

[0012]

One of the features of the present invention according to the above object is that a mold clamping ram in a mold clamping cylinder is a cylindrical body whose front and rear ends are closed, and the valve opening oil chamber is provided in both closing members. Open the flow path of the valve closing oil chamber by partially drilling and connecting the front and rear flow paths with the pipes provided in the mold clamping ram so that the flow path at the front of the mold clamping ram is the inlet and outlet side. There are two hydraulic paths, one for closing and one for closing.

Another feature is that a rapid feed cylinder is provided across the movable platen connected to the front end of the mold clamping ram in the mold clamping cylinder and the mold clamping cylinder, and the valve opening side is provided in the mold clamping ram. A hydraulic passage on the valve closing side is provided, and both hydraulic passages are provided with a switching valve to be directly connected to the drive hydraulic circuit of the mold clamping ram.

[0014]

[Operation] In the above configuration, the drilling of the flow path forming the hydraulic passage in the mold clamping ram is limited to the member that closes the front and rear ends of the mold clamping ram, and the mold clamping ram itself is subjected to drilling processing. Since it is not necessary, the hydraulic passage can be easily provided inside regardless of the length of the mold clamping ram.

Further, since the hydraulic passages of the valve opening oil chamber and the valve closing oil chamber are directly connected to the drive hydraulic circuit, the pressure oil can be supplied and discharged by operating the switching valve regardless of the operation of the fast-forward cylinder. As a result, the disc valve operates independently to open and close the passage of the mold clamping piston.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 1 in the drawing is a mold clamping cylinder, and the inside is a mold clamping ram 2.
The front part oil chamber 4 and the rear part oil chamber 5 are partitioned by the mold clamping piston 3 formed integrally around the rear part.

The two oil chambers are communicated with each other through a plurality of passages 6 and 6 formed in the mold clamping piston 3, and the passages 6 and 6 are clamped by a disc valve 7 provided in the rear oil chamber. Sometimes closed. Reference numerals 8 and 8 denote lid members before and after the mold clamping cylinder 1.

The mold clamping ram 2 has members 9 and 10 at its front and rear ends.
The movable platen 11 of the molding machine is connected to the front end of the cylindrical body. This movable plate 11 is slidably supported by tie bars 12, 12 penetrating the four corners, and piston rods 13b of a fast-forwarding piston 13 having a cylinder 13a fixed to the side of the mold clamping cylinder 1 are mounted on both sides. is there.

Further, the periphery of the rear end portion located in the rear oil chamber 5 of the mold clamping ram 2 is formed with a small diameter to form a step portion 14, and the disc is attached to the rear end portion of the mold clamping ram including the step portion 14. The valve 7 is inserted so as to be movable in the axial direction. The fitting portion between the rear portion of the mold clamping ram and the disc valve 7 has an annular convex portion 15 formed on the inner peripheral side of the step portion 14 and the disc valve 7.
The valve opening oil chamber 17 and the valve closing oil chamber 18 are partitioned by the piston 16 fitted to the rear end of the step portion.

In the closing members 9 and 10, the flow paths 19 and 20 of the valve opening oil chamber 17 and the flow path 2 of the valve closing oil chamber 18 are provided.
1 and 22 are bored at the same inner opening position. The front passages 19 and 21 penetrate the closing member 9, and the rear passages 20 and 22 are provided with branch passages 20a and 22a formed in the rear end portion of the mold clamping ram 2 to open the valve opening oil chamber. 17 and the valve closing oil chamber 18, respectively.

Such front and rear flow paths 19, 20 and 2
1, 22 are connected by pipes 23, 24 provided in the mold clamping ram 2, respectively, whereby front passages 19, 21 are connected.
Two hydraulic paths A and B for opening and closing with the inlet and outlet sides
(See FIG. 5) is configured inside the mold clamping ram.

In the above embodiment, the pipes 23 and 24 are arranged side by side in the mold clamping ram 2. However, in some cases, as shown in FIG. Lamb 2
It is also possible to provide the pipes 23, 24 at the central portion of the above and connect the front and rear channels 19, 20 and 21, 22 in the same manner as described above.

Also for the fast-forward cylinder 13,
Since the mold clamping ram 2 is hollow, it can be provided inside. FIG. 4 shows an example thereof, in which the fast-forward cylinder 13 is provided with a tubular piston rod 13b having double hydraulic passages 13c and 13d.
b is penetrated through the rear closing member 10 of the mold clamping ram 2 and the rear cover member 8 of the mold clamping cylinder 1, the cylinder 13a is housed in the mold clamping ram 2, and the cylinder 13a is accommodated in the rear closing member 1.
While being fixed to the inner center of 0, the protruding end of the piston rod 13b is fixed to the rear lid member 8.

In such a structure, the central hydraulic passage 13c
To supply the pressure oil to the front chamber 13f partitioned by the piston 13e to advance the mold clamping ram 2 at high speed, and also to apply the pressure oil from the hydraulic passages 13d on both sides to the rear chamber 13g to move the mold clamping ram 2 to the front chamber 13f. Can be retreated at high speed.

The hydraulic paths A and B are, as shown in FIG.
A switching valve 25 for opening and closing a desk valve is provided, and a hydraulic oil pressure is supplied to a drive hydraulic circuit 27 to which an electromagnetic proportional hydraulic pump 26 (a pump that generates a flow rate and a pressure according to a discharge amount by an electric signal input) is connected. The circuit 28 is directly connected.

The drive hydraulic circuit 27 is provided with a prefill valve hydraulic circuit 33 having a switching valve 31 and a check valve 32 for opening and closing the prefill valve 30 of the auxiliary tank 29 provided in the front oil chamber 4. A hydraulic circuit 36 for switching the hydraulic pressure between the front oil chamber 4 and the rear oil chamber 5 for switching the hydraulic pressure between the front oil chamber 4 and the rear oil chamber 5 and a pilot check valve 35, and a hydraulic pressure for rapid-feed cylinders 13, 13 provided with a switching valve 37. A circuit 38, a pilot circuit 39 for reversely flowing the pilot check valve 35, and a hydraulic circuit 41 having a switching valve 40 connected thereto are connected.

Next, the mold clamping step will be described with reference to FIG. In the mold opening completion state shown in the figure, the switching valve 25
Is switched to the b side to bring the valve opening oil chamber 17 side into the pressure oil supply state, and then the switching valve 37 is switched to the a side. The pistons 13b and 13b of the fast-forward cylinders 13 and 13 are moved forward by the pressure oil supplied to the rear oil chamber to move the movable plate 11
(See FIG. 1) is moved at high speed in the mold closing direction.

As a result, the mold clamping ram 2 whose front end is connected to the movable platen 11 also moves forward while pressing the pressure oil in the front oil chamber 4 with the piston 3. Since the pressure oil in the oil chamber 4 flows into the rear oil chamber 5 from the passages 6 and 6 of the piston 3, the pressure oil resistance of the front oil chamber 4 is reduced and the pressure of the rear oil chamber 5 at the time of high-speed mold closing is reduced. Negative pressure is prevented. Also, the rear oil chamber 5 due to the volume difference between the two oil chambers
The shortage of pressure oil is replenished from the auxiliary tank 29, and when the movable plate 11 reaches a predetermined position, the forward movement is switched to slow down to complete the high speed mold closing.

After the completion of the high speed die closing process, the switching valve 37 of the fast-forwarding cylinders 13, 13 is returned to the neutral position n, and the switching valve 25 is switched to the side a. Next, switch the switching valves 31 and 34 to b.
When switched to the side, pressure oil is supplied from the hydraulic path B to the valve closing oil chamber 18, and the disc valve 7 moves forward,
Close the passages 6 and 6 in close contact with the back surface of the mold clamping piston 3,
The front oil chamber 4 and the rear oil chamber 5 are completely shut off. Further, since the front oil chamber 4 is connected to the tank through the switching valve 34 and the pressure oil is supplied to the rear oil chamber 5, the oil pressure in the rear oil chamber 5 rises and a large mold clamping force is generated. , Strong die closure occurs there.

Next, in the mold opening step after the completion of molding, the rear oil chamber 5
It begins with the pressure relief. First, the switching valves 25, 31, 34 are returned to the neutral position n. Next, when the switching valve 40 is switched to the b side, the pilot pressure is guided to the pilot check valve 35 to open, and the pressure oil in the rear oil chamber 5 flows out to the tank to depressurize the valve closing oil chamber 18. The pressure is kept constant.

After the pressure is released, the switching valve 25 is switched to the side a to supply the pressure closing oil chamber 18 with pressure oil. As a result, the disc valve 7 advances to close the passages 6 and 6 and shut off the front and rear oil chambers. After that, when the switching valve 31 is switched to the b side and the switching valve 34 is switched to the a side, pressure oil is supplied to the auxiliary tank 29 and the front oil chamber 4, and the oil pressure raises the pressure of the front oil chamber 4. A large mold opening force commensurate with the load generated at the time of mold release is obtained.

At the time when this strong mold opening is completed, the switching valve 3
When the valves 1, 34, 40 are returned to the neutral position n shown in the figure and the switching valve 25 is switched to the side b, the pressure oil supplied to the valve opening oil chamber 17 causes the disk valve 7 to retract and the passage 6, 6. Open 6. Therefore, when the switching valve 37 is switched to the b side, pressure oil is supplied to the front chambers of the rapid-feed pistons 13 and 13, and the pistons 13b and 13b move backward together with the movable plate 11. At this time, since the front and rear oil chambers 4 and 5 are communicated with each other by opening the passages 6 and 6, the hydraulic resistance of the rear oil chamber 5 against the backward movement of the mold clamping ram 2 is removed, and the backward movement is performed at high speed. Further, the excess oil in the front oil chamber 4 caused by the area difference during the high speed movement is returned to the auxiliary tank 29.

The table below shows the position of the switching valve in each process.

[0034]

[Table 1]

[0035]

As described above, according to the present invention, the piston having the passage divides the inside of the mold clamping cylinder into two oil chambers, the front and rear, and the disc valve provided in the oil chamber on the mold clamping side of the piston hydraulically causes the passage. The mold clamping ram of the mold clamping device that opens and closes is composed of a cylindrical body whose front and rear ends are closed,
The flow passages of the valve opening oil chamber and the valve closing oil chamber are partially bored in the closing members at the front and rear ends, and the front and rear flow passages are connected by pipes provided in the mold clamping ram, respectively. Since there are two hydraulic passages for opening and closing with the passage on the front side of the clamping ram as the inlet and outlet sides, there are fewer processed parts than when the inside of the mold clamping ram is cut to form the passage. Even for a mold clamping ram having a long stroke, since only the closing member is required for the drilling process, the manufacturing cost is remarkably reduced, and as a result, the mold clamping device can be used for a large mold clamping device.

Further, according to the present invention, the rapid feed cylinder is arranged over the movable platen connected to the front end of the mold clamping ram and the mold clamping cylinder, and the hydraulic paths on the valve opening side and the valve closing side are provided in the mold clamping ram. Since both hydraulic paths are provided with a switching valve and directly connected to the drive hydraulic circuit of the mold clamping ram,
The disc valve can be operated independently, and when compressing or molding using a mold incorporating a spring member, the passage is closed by the disc valve, and the mold clamping ram is set at the position immediately before the mold is closed. It can be temporarily stopped.

Therefore, in compression molding, the resin in the mold can be compressed by advancing the mold clamping ram at a very low speed while the pressure in the rear oil chamber is sufficiently increased. Similarly, a mold incorporating a spring member can be used. On the other hand, it is possible to overcome the influence of the spring pressure at the time of closing due to the low pressure and the low speed, and the mold can be closed under the low pressure and the low speed without taking any special means.

Further, unless the valve closing oil chamber is depressurized, the disc valve will not open. Therefore, if the pressure in the rear oil chamber is lowered while maintaining the closed state, the mold clamping ram becomes the mold clamping piston. Since it moves backward while receiving hydraulic resistance, it is possible to balance the hydraulic resistance with the spring pressure and perform mold opening.As a result, even in the case of a mold incorporating a spring member, mold opening is smooth. It can be carried out.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a mold clamping device of a molding machine according to the present invention.

FIG. 2 is a cross sectional view of the same.

FIG. 3 is a vertical sectional view showing another embodiment of the hydraulic passage in the mold clamping ram.

FIG. 4 is a vertical cross-sectional view when a rapid-feed cylinder is provided in a mold clamping ram.

FIG. 5 is an explanatory view showing a schematic cross section of a mold clamping device and a hydraulic circuit thereof.

[Explanation of symbols]

 1 Clamping Cylinder 2 Clamping Ram 3 Clamping Piston 4 Front Oil Chamber 5 Rear Oil Chamber 6 Passage 7 Disc Valve 8 Clamping Cylinder Lid Member 9 Front Closing Member 10 Rear Closing Member 11 Movable Plate 13 Rapid Feed Cylinder 17 Valve Open oil chamber 18 Valve closed oil chamber 19,21 Front flow passage 20,22 Rear flow passage 23 Valve closed oil chamber side pipe 24 Valve open oil chamber side pipe 25 Disc valve switching valve 26 Electromagnetic proportional hydraulic pump 31 Switching valve for opening / closing prefill valve 34 Switching valve for strong mold clamping 35 Pilot check valve 37 Switching valve for fast-forward pilot 40 Pilot check valve Reverse flow switching valve A Valve opening side hydraulic path B Valve closing hydraulic path

Claims (4)

[Claims] 1. A mold clamping cylinder is divided into two front and rear oil chambers by a mold clamping piston integrally formed around a mold clamping ram, and both oil chambers are communicated by a passage formed in the mold clamping piston, and the mold clamping cylinder is connected. A disk valve for opening and closing the passage is provided in the rear oil chamber on the side of the valve so as to be axially movably fitted into the mold clamping ram, and the valve opening oil chamber and valve In a mold clamping device of a molding machine having a closed oil chamber, the mold clamping ram is a cylindrical body whose front and rear ends are closed, and the flow passages of the valve opening oil chamber and the valve closing oil chamber are partly formed in both closing members. Two hydraulic passages for opening and closing, with the front and rear flow passages being connected to each other by pipes provided in the mold clamping ram, and the flow passages at the front of the mold clamping ram being the inlet and outlet sides. A mold clamping device for a molding machine, comprising: 2. The mold clamping device for a molding machine according to claim 1, wherein the pipes serving as the hydraulic passages are doubled and provided in a central portion of a mold clamping ram, and the front and rear flow passages are connected to the pipes, respectively. A mold clamping device for a molding machine, characterized in that 3. The mold clamping device for a molding machine according to claim 1, wherein the rapid feed cylinder includes a tubular piston rod having a double hydraulic passage, and the piston rod is clamped to the rear closing plate of the mold clamping ram. The cylinder is housed in a mold clamping ram by penetrating the rear cover member of the cylinder, and the cylinder is fixed to the rear closing plate, while the piston rod is fixed to the rear cover member. Mold clamping device for molding machine. 4. A mold clamping cylinder is divided into two front and rear oil chambers by a mold clamping piston integrally formed around a mold clamping ram, and both oil chambers are communicated by a passage formed in the mold clamping piston, and the mold clamping cylinder is connected. A disk valve that opens and closes the passage is provided in the rear oil chamber on the side by being fitted and inserted in the mold clamping ram so as to be movable in the axial direction, and in the fitting and inserting portion of the disk valve and the mold clamping ram,
In a mold clamping device of a molding machine provided with a valve opening oil chamber and a valve closing oil chamber, a rapid feed cylinder is arranged between the movable plate connected to the front end of the mold clamping ram and the mold clamping cylinder, and the mold clamping ram. A mold clamping device for a molding machine, characterized in that the hydraulic paths for the valve opening side and the valve closing side are provided inside, and both hydraulic paths are directly connected to a drive hydraulic circuit of a mold clamping ram by providing a switching valve. .