JPH09267373A - Booster ram type mold-clamping apparatus and method for injection compression molding using booster ram type mold clamping apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a booster ram type mold clamping apparatus wherein the amt. of a hydraulic oil fed in a main cylinder room is sufficiently ensured when mold clamping is actuated in injection compression molding. SOLUTION: In the midst of high speed mold closing operation based on hydraulic pressure of a booster cylinder room 31, a hydraulic oil is fed in a main cylinder room 27 by a line switching means to switch it to low speed mold closing operation and after a movable mold 22 is guided to an injection starting position and a resin material is filled in a molding cavity, a hydraulic oil from a hydraulic pump 46 and a hydraulic oil from a hydraulic regeneration means 74 are both fed in the main cylinder room 27 by the first communication/ shuttering means 76 to make mold clamping work and a flow rate control means 90 and a pressure control means 92 are provided to a feeding line of the hydraulic oil from the hydraulic regeneration means 74.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a booster ram type mold clamping device suitably used in injection compression molding and an injection compression molding method using the booster ram type mold clamping device.

[0002]

2. Description of the Related Art Conventionally, as one of resin molding methods,
Molding is performed by injecting and filling resin material into the molding cavity of the mold closed at the mold stop position (injection start position) opened by the specified compression allowance, and then clamping the mold by clamping. An injection compression molding method in which a resin material in a cavity is compressed is known, and an effect such as prevention of defects such as sink marks and warpage in products is recognized.

Further, as a kind of direct pressure type mold clamping device used for resin molding including injection compression molding, a main ram slidably fitted in a main cylinder chamber has been conventionally used.
A booster ram having an outer diameter smaller than the outer diameter of the main ram is coaxially inserted to form a booster cylinder chamber in the main ram, and pressure oil is supplied to and discharged from the main cylinder chamber and the booster cylinder chamber. There is known a booster ram type mold clamping device in which a movable plate mounted on the main ram is moved toward and away from a fixed plate by driving the main ram. In such a booster ram type mold clamping device, by supplying hydraulic oil to the booster cylinder chamber and driving the main ram by the hydraulic pressure of the booster cylinder chamber, it is possible to move the movable plate at high speed and operate the main cylinder chamber. By supplying oil and driving the main ram by the hydraulic pressure in the main cylinder chamber, the movable plate can be driven at high pressure.

When performing injection compression molding using such a booster ram type mold clamping device, for example,
By driving the main ram with the hydraulic pressure in the booster cylinder chamber, the movable mold is moved at a high speed relative to the fixed mold to reach the predetermined injection start position, and the resin material is formed in the molding cavity formed between the molds. After injecting and filling, by driving the main ram with the hydraulic pressure in the main cylinder chamber,
It is conceivable that the movable mold is subjected to a high-pressure mold clamping operation with respect to the fixed mold to compress the resin material in the molding cavity. By doing so, a high-speed mold matching operation is realized, the molding cycle can be shortened, and the compression pressure can be advantageously obtained.

However, since a large amount of hydraulic oil is required for injection during injection compression molding, the hydraulic pump capacity of the hydraulic oil supplied to the main cylinder chamber is likely to be insufficient, and a sufficient mold is required during mold clamping operation. There was an inherent problem that it was difficult to obtain a tightening speed, and in particular, when molding a thin product, the compression speed for the resin material was insufficient, and it was difficult to generate an effective resin flow by compression. there were.

Further, in the injection compression molding using the booster ram type mold clamping device as described above, the movable mold is guided to a predetermined injection start position by driving the main ram by the hydraulic pressure in the booster cylinder chamber. However, at that time,
There is also a problem that it is difficult to sufficiently secure the stop position accuracy of the movable mold, and the accuracy of control of the compression allowance is reduced, and it is difficult to stably obtain the desired compression effect.

[0007]

The present invention has been made in view of the circumstances as described above, and the problem to be solved is that the amount of hydraulic oil supplied to the main cylinder chamber during the mold clamping operation is sufficient. It is an object of the present invention to provide a booster ram type mold clamping device and an injection compression molding method using the booster ram type mold clamping device, which can be ensured in accordance with the present invention and can obtain an appropriate compression speed and compression pressure easily and stably.

Further, according to the present invention, the accuracy of the stop position of the movable mold to the injection start position is improved, and the compression margin for the resin material can be controlled with high accuracy, and the booster ram type clamping device and the booster ram type mold. It is also an object to provide an injection compression molding method using a clamping device.

Furthermore, the present invention is advantageously used in injection compression molding, and uses a spring type in which a spring for exerting an urging force in the mold opening direction is built in between a fixed die and a movable die. According to a general injection molding method that does not have a resin compression step, a booster ram that can be advantageously used in spring mold molding in which both molds are closed and clamped and then a resin material is injected and filled into the molding cavity. It is also an object to provide a mold clamping device.

[0010]

In order to solve such a problem, a feature of the present invention relating to a booster ram type mold clamping device is that a booster ram is inserted into a main ram slidably arranged in a main cylinder chamber, A booster cylinder chamber is formed in the main ram, and hydraulic oil from a hydraulic pump is supplied to and discharged from the booster cylinder chamber and the main cylinder chamber to drive the main ram. On the other hand, by moving the movable mold mounted on the movable plate to the predetermined injection start position, and injecting and filling the resin material into the molding cavity formed between both molds, the movable mold and the fixed mold. In a booster ram type mold clamping device in which a resin material in a molding cavity is compression-molded by performing a mold clamping operation of (a) the hydraulic oil from the hydraulic pump. And allowed to feed into the chamber, by driving the main ram by a hydraulic force of the booster cylinder chamber, after moved fast mold the movable mold in the die closing direction,
By supplying hydraulic oil from the hydraulic pump to the main cylinder chamber and driving the main ram by the hydraulic pressure of the main cylinder chamber to move the movable mold at a low speed, the movable mold is Line switching means for leading to the injection start position,
(B) a pressure accumulating means that is connected to the main cylinder chamber and supplies a driving oil in the mold closing direction to the main ram by supplying hydraulic oil to the main cylinder chamber; and (c) a pressure accumulating means. By providing a connection line to the main cylinder chamber, blocking the connection line, and connecting the connection line after injection and filling of the resin material into the molding cavity, the hydraulic oil from the hydraulic pump A first communication for causing the movable mold to perform a mold clamping operation by supplying the working oil from the pressure accumulating means together to the main cylinder chamber and driving the main ram by the oil pressure in the main cylinder chamber. A shutoff means, (d) a flow rate control means provided in a connection line of the pressure accumulating means to the main cylinder chamber, and (e) a pressure control means provided in a connection line of the pressure accumulating means to the main cylinder chamber. And have In booster ram type mold clamping device.

In the booster ram type mold clamping device having the structure according to the present invention, pressure oil is supplied from both the hydraulic pump and the pressure accumulating means to the main cylinder chamber on the mold closing side during the mold clamping operation. Is driven in the mold closing direction, so that a sufficient amount of hydraulic oil and hence the mold clamping speed can be secured, and the flow rate control means and the pressure control means enable the mold clamping speed and the mold clamping pressure during the mold clamping operation. Can be easily set and controlled over a wide range. Therefore, even when the hydraulic pump capacity is small, it is possible to easily set conditions such as an appropriate mold clamping speed, and it is possible to obtain the desired effects of injection compression molding advantageously and stably. It will be. In the present invention as set forth in claim 1, the main cylinder chamber is, as a general rule, a mold closing side main cylinder chamber that applies a driving force in the mold closing direction to the main ram by the supply of pressure oil, and the main cylinder chamber The mold accommodating means includes a mold-opening-side main cylinder chamber that exerts a driving force in the mold-opening direction on the main ram by the supply, but as is apparent from the description of claim 1, the pressure accumulating means supplies the pressure oil. , The main ram is connected to the mold closing side main cylinder chamber that exerts a driving force in the mold closing direction.

Further, in the booster ram type mold clamping device having the structure according to the present invention, the main ram is moved based on the oil pressure in the main cylinder chamber from the middle of the mold matching operation until the movable mold is guided to the injection start position. Since it is driven, the accuracy of the stop position of the movable mold is improved, and the compression margin for the resin material can be controlled with high accuracy.

Further, in the booster ram type mold clamping device according to the present invention, as the line switching means, for example, as described in claim 2, the line switching means is in the mold closing direction of the movable mold. 4. A structure for switching to a low speed mold moving operation in the middle of the high speed mold moving operation to move the movable mold in the mold closing direction at a low speed so as to guide the movable mold to the injection start position. As described, after the line switching means guides the movable mold in the mold closing direction at high speed by moving the mold to the mold closing completed position,
Any configuration in which the movable mold is switched to the low speed mold movement operation to move the movable mold at a low speed in the mold opening direction to guide it to the injection start position can be suitably adopted.

Even if any of such line switching means is adopted, the effects of the present invention as described above can be effectively exhibited.

Further, in the present invention relating to the booster ram type mold clamping device, as described in claim 4, a sequence valve is arranged in the main line connecting the hydraulic pump to the main cylinder chamber on the mold closing side. At the very least, hydraulic oil is supplied to the main cylinder chamber on the mold closing side via the sequence valve by increasing the hydraulic pressure of the booster line connecting the hydraulic pump to the booster cylinder chamber, and the sequence valve is bypassed. Thus, the bypass line connecting the booster line to the main cylinder chamber on the mold closing side and the bypass line are cut off,
A configuration in which a second communication / blocking means for communicating the bypass line when switching from the high speed type movement to the low speed type movement is provided can also be suitably adopted.

By adopting such a constitution, it is possible to carry out the conventionally known spring-type molding under the condition that the bypass line is always blocked by the second communicating / blocking means. Moreover, when performing injection compression molding, the hydraulic oil is supplied to the main cylinder chamber from the middle of the mold matching operation through the bypass line, so that the high-speed mold movement based on the hydraulic pressure in the booster cylinder chamber prevents the main cylinder from moving. Switching to low-speed type movement based on the hydraulic pressure in the chamber can be made smoothly, and instability of control due to obstruction of hydraulic oil supply to the main cylinder chamber by the sequence valve, etc. is advantageously prevented, and mold matching operation is performed. Also, the operation can be stabilized during the mold clamping operation.

Further, in the present invention relating to the booster ram type mold clamping device, as described in claim 5, after the movable mold is moved to the compression completion position by the mold clamping operation, the pressure accumulating means. The connection line to the main cylinder chamber is cut off by the first communication / cutoff means, and the mold clamping holding pressure of the main cylinder chamber is maintained by supplying hydraulic oil from the hydraulic pump to the main cylinder chamber. A configuration that can be adopted is also suitably adopted.

By adopting such a structure, even a hydraulic pump having a small capacity can maintain a large mold clamping holding pressure while ensuring a sufficiently large mold clamping speed, and moreover, the mold clamping holding is performed. By supplying the hydraulic oil to the pressure accumulating means and accumulating the pressure at the stage, it is possible to improve the molding cycle.

On the other hand, the features of the present invention relating to the injection compression molding method using the booster ram type mold clamping device are as follows:
A booster ram is inserted into a main ram slidably arranged in the main cylinder chamber to form a booster cylinder chamber in the main ram, and hydraulic oil from a hydraulic pump is supplied to the booster cylinder chamber and / or the main cylinder chamber. By using the booster ram type mold clamping device, the movable dies mounted on the movable platen can be driven toward and away from the fixed mold mounted on the fixed platen by ejecting and driving the main ram. After moving the movable mold with respect to the fixed mold and injecting and filling a resin material into a molding cavity formed between the two molds at a predetermined injection start position, the movable mold and the fixed mold are fixed. When injection compression molding is performed by pressing the mold to compress the resin material in the molding cavity, hydraulic oil is supplied to the booster cylinder chamber to supply hydraulic oil to the booster cylinder chamber. Driving the main ram by moving the movable mold in the mold closing direction, and then supplying hydraulic oil to the main cylinder chamber to drive the main ram by the hydraulic pressure of the main cylinder chamber. By switching to a low speed mold movement to guide the movable mold to the injection start position, and after injecting and filling the resin material into the molding cavity, connect a pressure accumulator to the main cylinder chamber, On the other hand, by supplying hydraulic oil from the pressure accumulator together with the hydraulic pump, the main ram is driven based on the hydraulic pressure in the main cylinder chamber to perform the mold clamping operation.

According to such a method of the present invention, the movable platen is driven based on the hydraulic pressure in the main cylinder chamber until the movable mold is guided to the injection start position from the middle of the mold matching operation. In addition to achieving excellent stop position accuracy of the movable plate, pressure oil is supplied to the main cylinder chamber from both the hydraulic pump and the pressure accumulating means during the mold clamping operation. The mold clamping speed is ensured, which makes it possible to obtain the desired effect of injection compression molding advantageously and stably.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described in detail with reference to the drawings.

First, FIG. 1 schematically shows a booster ram type mold clamping device having a structure according to the present invention. In this figure, 10 is a mold clamping device main body, which has a main cylinder 12. Further, a fixed platen 14 is arranged to face the main cylinder 12 with a predetermined distance therebetween, and the fixed platen 14 has four tie bars 1 with respect to the main cylinder 12.
8 are connected in a fixed relative position. Furthermore,
A movable platen 16 is arranged between the main cylinder 12 and the fixed platen 14, and is supported by a tie bar 18 so that the movable platen 16 is guided toward and away from the fixed platen 14. The fixed mold 20 mounted on the fixed platen 14 and the movable mold 22 mounted on the movable platen 16 are adapted to be opened and closed.

In the cylinder chamber of the main cylinder 12,
A main ram 26 is axially slidably and liquid-tightly inserted, and a front end portion of the main ram 26 is projected forward from the main cylinder 12 and fixed to the movable platen 16. The main cylinder chamber is liquid-tightly divided into a front side and a rear side by a piston portion of the main ram 26. Therefore, the mold closing side main cylinder chamber on the front side (hereinafter, simply referred to as “main cylinder chamber”). 2) and a rear mold opening side main cylinder chamber (hereinafter referred to as “mold opening cylinder chamber”) 29. Furthermore, the main cylinder 1
2 to the rear end side (left side in FIG. 1) of the valve cylinder 24
Are integrally provided, and the cylinder chamber 25 of the valve cylinder 24 is the main cylinder chamber 27 of the main cylinder 12.
Is coaxially formed in the state of being communicated with.

In the valve cylinder chamber 25 and the main cylinder chamber 27, a cylindrical booster ram 28 having a diameter smaller than that of the main ram 26 extends in the axial direction from the rear end of the valve cylinder 24. It is arranged in such a length that it penetrates 25 and reaches the main cylinder chamber 27. On the other hand, the main ram 26 is formed with a bottomed hole 30 that opens to the rear end surface, and the tip end portion of the booster ram 28 is slidably and liquid-tightly inserted into the bottomed hole 30 so that a booster cylinder is formed. A chamber 31 is formed.

Further, a communication hole 32 is formed in the peripheral wall portion of the valve cylinder 24 so as to penetrate the valve cylinder chamber 2.
5 is connected to the external oil tank 36 from the communication hole 32 through the supply / discharge line 34. A substantially cylindrical prefill valve 38 is slidably accommodated in the valve cylinder chamber 25, and the prefill valve 38 is held by a coil spring 40 at the axially front end of the valve cylinder chamber 25. The pressure oil is supplied to the drive cylinder chamber 42 formed on the outer circumference of the prefill valve 38 so that the prefill valve 38 can be moved by the coil spring 4.
It can be displaced axially rearward against an urging force of zero. The pre-fill valve 38 is positioned at the axially front end portion in the valve cylinder chamber 25 to close the communication hole 32, while the pre-fill valve 38 is axially rear end portion in the valve cylinder chamber 25. By being positioned at, the communication hole 32 is opened and the main cylinder chamber 27 is connected to the external oil tank 36 through the valve cylinder chamber 25 and the supply / discharge line 34. The drive cylinder chamber 42
Is connected to a hydraulic pump 46 via an electromagnetic switching valve 44, and the switching operation of the hydraulic pump 46 selectively connects the drive cylinder chamber 42 to the hydraulic pump 46 or the external oil tank 36. It is like this.

On the other hand, the booster cylinder chamber 31 is connected to the electromagnetic switching valve 52 and the electromagnetic switching valve 53 by the booster line 50 through the inner hole of the booster ram 28. By the switching operation of the electromagnetic switching valve 52,
The booster cylinder chamber 31 is connected to or disconnected from the hydraulic pump 46, and the booster cylinder chamber 31 is switched by the switching operation of the electromagnetic switching valve 53.
The external oil tank 36 is connected / disconnected via the throttle 33. That is, the electromagnetic switching valve 52
Switching operation of the booster cylinder chamber 31 to the hydraulic pump 46.
By connecting to the booster cylinder chamber 3
While the booster cylinder chamber 31 is connected to the external oil tank 36 by the switching operation of the electromagnetic switching valve 53, the booster cylinder chamber 31 is supplied to the external oil tank 36.
Is designed to be depressurized. A relief valve 54 is connected to the line that supplies the hydraulic oil of the hydraulic pump 46 to the booster line 50. The relief valve 54 allows the hydraulic pressure of the hydraulic oil discharged from the hydraulic pump 46 to be a constant value. It is kept below. Further, the booster line 50 is connected to a protection line 58 having a check valve 56 that allows the reverse flow of the hydraulic oil from the booster cylinder chamber 31 to the hydraulic pump 46 side so as to bypass the electromagnetic switching valve 52. ing.

Further, a main line 64 is connected to the booster line 50 connecting the booster cylinder chamber 31 to the electromagnetic switching valve 52. The main line 64 is connected to the main line 64.
Thus, the electromagnetic switching valve 52 is connected to the main cylinder chamber 27 through the valve cylinder chamber 25 via the check valve-equipped sequence valve 60. The main cylinder chamber 27 is connected / disconnected to the hydraulic pump 46 by the switching operation of the electromagnetic switching valve 52, and the switching operation of the electromagnetic switching valve 53 connected to the booster line 50 is performed. The main cylinder chamber 27 is adapted to communicate / disconnect with the external oil tank 36. That is, by connecting the main cylinder chamber 27 to the hydraulic pump 46 by switching the electromagnetic switching valve 52, hydraulic oil is supplied to the main cylinder chamber 27, while switching the electromagnetic switching valve 53. Main cylinder chamber 27
Is connected to the external oil tank 36 through the throttle 33, so that the main cylinder chamber 27 is depressurized.

Since the sequence valve 60 with a check valve is arranged on the main line 64, the booster line 5 for supplying the working oil to the booster cylinder chamber 31.
When the pressure of 0 rises above a certain value, the hydraulic oil is supplied to the main cylinder chamber 27 through the main line 64. Further, when the operating oil is supplied to the booster cylinder chamber 31 or the main cylinder chamber 27 by the switching operation of the electromagnetic switching valve 52, the mold opening cylinder chamber 29 is connected to the external oil tank 36 via the electromagnetic switching valve 52. It is designed to be depressurized. Furthermore, hydraulic oil is supplied from the hydraulic pump 46 to the mold opening cylinder chamber 29 by the switching operation of the electromagnetic switching valve 52.

A bypass line 66 is connected to the booster line 50 that connects the electromagnetic switching valve 52 to the booster cylinder chamber 31.
6, the both sides of the sequence valve 60 with a check valve (the electromagnetic switching valve 52 side and the main cylinder chamber 27 side in the main line 64) are communicated with each other. An electromagnetic switching valve 68 is arranged on the bypass line 66, and the bypass line 66 is connected / disconnected by the switching operation of the electromagnetic switching valve 68. In short, by connecting the bypass line 66 by the switching operation of the electromagnetic switching valve 68, the hydraulic oil from the hydraulic pump 46 is directly supplied to the main cylinder chamber 27 without passing through the sequence valve 60 with check valve. It is supposed to be.

Further, an accumulator 74 as a pressure accumulating means is connected to a pump line 70 for guiding the hydraulic oil supplied from the hydraulic pump 46 to the electromagnetic switching valve 52 through a connection line 72. And connection line 7
By operating the open / close valve 76 arranged above the accumulator 74, the accumulator 74 is connected / disconnected to / from the pump line 70. Under the communication state of the open / close valve 76, the hydraulic oil accumulated in the accumulator 74 is transferred to the electromagnetic switching valve 52
Can be guided to the main line 64 by the switching operation.

A pressure accumulating pump 7 for supplying pressure oil to the accumulator 74 to accumulate the pressure is connected to the connection line 72.
8 is connected via a check valve 80, and a pressure relief valve 82 for connecting the accumulator 74 to the external oil tank 36 is connected. Further, a pressure switch 86 is provided on the connection line 72 connecting the accumulator 74 to the pump line 70, while a relief valve 84 is connected on the pressure oil supply line of the pressure accumulation pump 78. The electromagnetic switch valve 88 for controlling the operation of the relief valve 84 is switched by the pressure switch 86 according to the hydraulic pressure of the accumulator 74, so that the hydraulic pressure of the accumulator 74 is controlled to a predetermined value. In short, the electromagnetic switching valve 88
Is a control valve for charging the accumulator 74 by the pressure-accumulation pump 78. Regardless of the operation of the mold clamping device body 10, when the pressure of the accumulator 74 decreases, the pressure switch 86 is turned on and the electromagnetic switching valve 88 is excited. As a result, hydraulic oil is supplied from the pressure accumulation pump 78 to the accumulator 74 to increase its pressure, while the pressure switch 86 is turned off and the electromagnetic switching valve 88 is demagnetized when the pressure of the accumulator 74 reaches a predetermined value. As a result, the hydraulic oil supplied from the pressure accumulation pump 78 is guided to the external oil tank 36, and the hydraulic oil having a predetermined pressure is stored in the accumulator 74.

On the connection line 72 for guiding the hydraulic oil accumulated in the accumulator 74 to the pump line 70,
A flow rate control valve 90 as a flow rate control means is provided, and the flow rate control valve 90 allows the accumulator 74 to be provided.
The flow rate (flow rate per unit time) of the hydraulic oil supplied from the to the pump line 70 can be arbitrarily adjusted. Furthermore, in the connection line 72, an electromagnetic relief valve 92 as a pressure control means is connected to the flow control valve 90.
Is connected on the pump line 70 side, and the pressure of the hydraulic oil supplied from the accumulator 74 to the pump line 70 can be arbitrarily adjusted by the electromagnetic relief valve 92.

Further, particularly in this embodiment, although not explicitly shown in the drawing, an electromagnetic switching valve 68 connected to the booster line 50 and the main line 64 through a bypass line 66, and a pump line 70. Accumulator 74, pressure-accumulation pump 78, flow control valve 90, electromagnetic relief valve 92 connected through a connection line 72.
Etc. are integrated as a unit 94, and can be retrofitted to the hydraulic circuit of the mold clamping device. In short, the part excluding the unit 94 (the hydraulic pump 4
6 and booster line 50, main line 64, electromagnetic switching valve 52, sequence valve 60 with check valve, etc.)
It is a general hydraulic circuit in a booster ram type mold clamping device used in general injection molding (for example,
Jpn. Pat. Appln. KOKAI No. 4-18817), therefore, it is necessary to remodel the booster ram type mold clamping device having such a conventionally known hydraulic circuit by mounting the unit 94 as described above. Without doing so, it is possible to obtain the booster ram type mold clamping device having the structure of this embodiment as described above.

Next, a specific example of an operation mode for carrying out injection compression molding using the mold clamping device of the present embodiment having the above-mentioned structure will be described.

First, the solenoid C of the electromagnetic switching valve 52 is excited to excite the hydraulic pump 46 while the mold is open.
The hydraulic oil from the is supplied to the booster cylinder chamber 31. At the same time, the electromagnetic switching valve 44 is demagnetized and the prefill valve 38 is moved rearward so that the main cylinder chamber 27 can communicate with the external oil tank 36 through the communication hole 32. As a result, the main ram 26 is advanced at a high speed based on the hydraulic pressure in the booster cylinder chamber 31, and as shown in FIG. It can be moved at high speed in the forward direction).

Subsequently, the movable die 22 moves forward, and the movable platen 1
When a cam (not shown) attached to 6 pushes a first limit switch (not shown), the booster cylinder chamber 31 is adjusted by adjusting the discharge oil amount of the hydraulic pump 46.
Reduce the amount of oil supplied to the vehicle to decelerate. As a result, the forward speed of the main ram 26 is reduced, so that the movable mold 22 is moved to the fixed mold 2 as shown in the section of points: a to b in FIG.
The deceleration mold is moved in the mold closing direction with respect to 0.

Next, when the movable die 22 further moves forward and the cam attached to the movable platen 16 pushes the second limit switch (not shown), the electromagnetic switching valve 44 is excited,
By moving the prefill valve 38 forward,
The main cylinder chamber 27 is closed. At the same time, the electromagnetic switching valve 68 is excited to supply the hydraulic oil from the hydraulic pump 46 to the main cylinder chamber 27 through the bypass line 66. As a result, the main ram 26 is moved forward at a low speed based on the hydraulic pressure in the main cylinder chamber 27, and the movable mold 22 is fixed to the fixed mold as shown in the section of points: b to c in FIG. Type 2
The mold is moved at a low speed in the mold closing direction with respect to 0.

Further, the movable mold 22 is moved to the predetermined injection start position: c by the low speed mold movement, and the cam mounted on the movable plate 16 is moved to the third limit switch (not shown). When is pressed, the electromagnetic switching valve 5
2 is demagnetized, and the supply of hydraulic oil from the hydraulic pump 46 to the main cylinder chamber 27 and the booster cylinder chamber 31 is temporarily stopped, and the movable mold 22 is stopped and held at the injection start position: c. The injection start position: c is a position where the fixed mold 20 and the movable mold 22 are opened by a predetermined amount from the mold closing completion position: e.

The fixed mold 20 and the movable mold 2 are held while the movable mold 22 is held at the injection starting position: c.
A predetermined resin material is injected and filled into the molding cavity formed between the two by an injection device (not shown).

After the injection and filling of the resin material is completed, and after a certain period of time set by the timer mechanism or the like has passed, the solenoid C of the electromagnetic switching valve 52 is excited and the hydraulic oil from the hydraulic pump 46 is supplied. , Again to the main cylinder chamber 27. At the same time, the opening / closing valve 76 on the connection line 72 is opened to supply the hydraulic oil from the accumulator 74 to the main cylinder chamber 27. As a result, the main ram 26 is advanced by a high pressure based on the oil pressure in the main cylinder chamber 27, and the movable mold 22 is completely compressed, as shown in the section of points: cd in FIG. Position: The mold is moved to the position d and the mold clamping operation is performed.
The compressive action is applied to the resin material filled in the molding cavity of (1).

Then, the movable mold 22 is clamped by the mold clamping operation.
When it is confirmed by the pressure of the main cylinder chamber 27, the limit switch, etc. that it has been moved to the compression completion position: d, the opening / closing valve 76 is closed to shut off the accumulator 74 from the main cylinder chamber 27. Only by the pressure oil supplied from the hydraulic pump 46 to the main cylinder chamber 27,
The movable mold 22 is clamped and held with respect to the fixed mold 20.

After that, after elapse of a predetermined cooling and solidifying time,
After demagnetizing the electromagnetic switching valve 44 and exciting the electromagnetic switching valve 53 to release the mold clamping pressure, the electromagnetic switching valve 52
The solenoid O is excited and hydraulic oil is supplied from the hydraulic pump 46 to the mold opening cylinder chamber 29 to drive the main ram 26 backward and open the movable mold 22 with respect to the fixed mold 20. , Take out the molded product.

As is apparent from the above description, in the present embodiment, the line switching means for switching from the high speed type movement to the low speed type movement is configured to include the electromagnetic switching valve 52 and the electromagnetic switching valve 68. The first communication / cutoff means for connecting / disconnecting the connection line is the open / close valve 76.
And the sequence valve 60.
A second communication / cutoff means for connecting / disconnecting the bypass line is constituted by the electromagnetic switching valve 68.

According to such injection compression molding, since the pressure oil is supplied to the main cylinder chamber 27 from both the hydraulic pump 46 and the accumulator 74 during the mold clamping operation, a sufficient amount of the hydraulic oil and hence the mold clamping speed are obtained. Is secured. Further, the supply flow rate and the supply pressure of the pressure oil supplied from the accumulator 74 to the main cylinder chamber 27 can be appropriately adjusted by the flow rate control valve 90 and the electromagnetic relief valve 92.

Therefore, even if the capacity of the hydraulic pump 46 is small, the mold clamping speed and the mold clamping pressure can be advantageously secured, and thereby the desired effect of the injection compression molding can be advantageously and stabilized. It becomes possible to obtain it.

According to the injection compression molding as described above,
The hydraulic oil is supplied to the main cylinder chamber 27 from the middle of the mold matching operation (refers to an operating region for moving the movable mold to the injection start position from the start of the movement of the movable mold), and the oil in the main cylinder chamber 27 is supplied. Since the main ram 26 is driven forward based on the pressure, the position control accuracy of the main ram 26 is improved as compared with the case where the main ram 26 is driven forward based on the oil pressure in the booster cylinder chamber 31. Therefore, the control accuracy of the stop position when stopping the movable mold 22 at the injection start position and thus the compression margin for the resin material can be improved, and the desired compression amount can be stably applied to the resin material. Is possible.

Further, in the mold clamping device of this embodiment, the main line 64 is provided with the bypass line 66 that bypasses the sequence valve with check valve 60, and the high speed mold movement based on the hydraulic pressure in the booster cylinder chamber 31 is performed. When the mode is switched to the low speed type movement based on the hydraulic pressure of the main cylinder chamber 27, the hydraulic oil is supplied to the main cylinder chamber 27 through the bypass line 66.
Since the hydraulic pressure in the booster cylinder chamber 31 is low, the sequence valve 60 with a check valve is prevented from interrupting the supply of hydraulic oil to the main cylinder chamber 27, and the switching to the low speed type movement is smoothly performed. At the same time, the booster cylinder chamber 31 and the main cylinder chamber 27 are moved during low speed movement.
Since the hydraulic oil is simultaneously supplied to and, the hydraulic pressure and the mold moving speed can be easily controlled.

Further, in the mold clamping device of this embodiment, since the sequence valve 60 with a check valve is arranged on the main line 64 without impairing the compression moldability,
By not functioning the bypass line 66, the mold clamping device of the present embodiment is advantageous even when performing general injection molding, which is not compression molding, in which a resin material is injected and filled into the molding cavity after mold matching and mold clamping. Can be used.

By the way, in the first specific example of the above-mentioned operation mode, the movable mold is switched to the low-speed mold movement operation during the high-speed mold movement operation in the mold closing direction, whereby the movable mold is Although the mold was guided to the injection start position by the low speed mold movement in the mold closing direction, instead, as shown in FIG. 3, the movable mold is once moved to the high speed mold in the mold closing direction. After being guided to the mold closing completion position by the operation, it may be switched to the low speed mold moving operation, and the movable mold may be again moved at a low speed in the mold opening direction to be guided to the injection start position.

Specifically, first, with the mold open,
The movable mold 22 is moved to the fixed mold 2 based on the hydraulic pressure in the booster cylinder chamber 31 by the same control as in the first specific example.
When it is confirmed that the movable mold 22 has reached the preset deceleration position: a while moving the mold at a high speed in the mold closing direction with respect to 0, by adjusting the discharge oil amount of the hydraulic pump 46, The movable mold 22 is moved in the mold closing direction by the deceleration mold.

Then, as shown in the section of points a to e in FIG. 3, the decelerating mold movement of the movable mold 22 in the mold closing direction moves the movable mold 22 to the mold closing completion position. Then, the movable mold 22 is once closed with respect to the fixed mold 20.

Next, without increasing the mold closing force, the electromagnetic switching valve 44 is excited to seal the main cylinder chamber 27 with the prefill valve 38, and at the same time, the electromagnetic switching valve 5 is closed.
The solenoid O of No. 2 and the electromagnetic switching valve 53 are excited to supply the working oil from the hydraulic pump 46 to the mold opening cylinder chamber 29, and the main cylinder chamber 2 through the main line 64.
The hydraulic oil 7 is discharged to the oil tank 36 and released. As a result, based on the hydraulic pressure in the mold opening cylinder chamber 29,
The main ram 26 is retracted at a low speed, and a point in FIG.
As shown in the section c, the movable mold 22 is moved at a low speed in the mold opening direction with respect to the fixed mold 20.
At this time, a throttle 33 is provided in the pressure release line from the main cylinder chamber 27 so that the pressure in the main cylinder chamber 27 can be maintained.

When it is confirmed that the movable die 22 is moved to the predetermined injection start position: c by the low speed die movement, the electromagnetic switching valve 52 and the electromagnetic switching valve 53 are demagnetized ( The electromagnetic switching valve 44 is kept excited, and the supply of hydraulic oil from the hydraulic pump 46 to the mold opening cylinder chamber 29 is stopped to stop and hold the movable mold 22 at the injection start position: c.

After that, injection, compression, mold clamping and holding, and mold opening are performed through the same controls and steps as those in the first embodiment, and the desired molded product is taken out.

Therefore, even in such an operating mode,
At the time of low-speed mold movement that guides the movable mold 22 to the injection start position: c, a driving force is generated by the supply of hydraulic oil to the main cylinder chamber 29 on the mold opening side, and from the main cylinder chamber 27 on the mold closing side. Since the discharge of the hydraulic oil is restricted by the throttle 33, the main ram and hence the movable mold 22 can be controlled at a very low speed, and the movable mold 22 is injected at the injection start position: c as in the first specific example. It is possible to lead to high accuracy.

Although the embodiments of the present invention have been described above in detail, these are literal examples and the present invention should not be construed as being limited to such specific examples.

For example, it is not always necessary to form the electromagnetic switching valve 68, the accumulator 74, the accumulator pump 78, the flow control valve 90, the electromagnetic relief valve 92, etc. into a unit structure.

It is also possible to use a hydraulic pump for driving the main ram together as a pump for accumulating pressure in the accumulator.

Furthermore, in the above-described embodiment, the mold moving speed during the mold matching operation is such that the high speed mold moving and the decelerating mold moving based on the oil pressure in the booster cylinder chamber 31 and the low speed mold moving based on the oil pressure in the main cylinder chamber 27. However, the high speed movement based on the hydraulic pressure in the booster cylinder chamber 31 may be directly switched to the low speed movement based on the hydraulic pressure in the main cylinder chamber 27.

Further, the mold clamping pressure in the mold clamping operation can be controlled in a plurality of stages depending on the resin material, the shape of the molded product, and the like.

In addition, although not enumerated one by one, the present invention
Based on the knowledge of those skilled in the art, various changes, modifications, improvements, and the like can be made, and unless such embodiments depart from the spirit of the present invention.
Both are included within the scope of the present invention,
Needless to say.

[0062]

As is apparent from the above description, in the booster ram type mold clamping device having the structure according to the present invention, the hydraulic pump capacity is supplemented by the pressure accumulating means, and the mold clamping speed can be advantageously secured. At the same time, the mold clamping speed and the mold clamping pressure can be adjusted by the flow rate control means and the pressure control means, so that the desired effect of the injection compression molding can be obtained advantageously and stably.

In the booster ram type mold clamping device, the movable mold is moved at a high speed based on the hydraulic pressure in the booster cylinder chamber in the initial stage of mold matching.
At the end of mold matching, the movable mold is moved at a low speed based on the hydraulic pressure in the main cylinder chamber.Therefore, the stop position when stopping the movable mold at the injection start position, and thus the control accuracy of the compression allowance for the resin material, is improved. Can be improved.

Further, according to the method of the present invention, in the mold matching operation, the movable mold is guided to the injection start position by the low speed mold movement based on the hydraulic pressure in the main cylinder chamber.
The stop position of the movable mold, and thus the control accuracy of the compression margin for the resin material, is advantageously ensured, and the hydraulic pump capacity is supplemented by the pressure accumulating means during the mold clamping operation, so that the mold clamping speed can be advantageously ensured. is there.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an outline of a booster ram type mold clamping device as one embodiment of the present invention.

FIG. 2 is a graph for explaining a specific example of mold matching and mold clamping operations according to the present invention regarding an injection compression molding method.

FIG. 3 is a graph for explaining another specific example of the mold matching and mold clamping operations according to the present invention regarding the injection compression molding method.

[Explanation of symbols]

 10 Mold clamping device body 12 Main cylinder 14 Fixed plate 16 Movable plate 20 Fixed mold 22 Movable mold 26 Main ram 27 Main cylinder chamber 28 Booster ram 31 Booster cylinder chamber 46 Hydraulic pump 50 Booster line 64 Main line 74 Accumulator

Claims (6)

[Claims] 1. A booster ram is inserted into a main ram slidably arranged in the main cylinder chamber, a booster cylinder chamber is formed in the main ram, and an operation from a hydraulic pump is performed in the booster cylinder chamber and the main cylinder chamber. By supplying and draining oil and driving the main ram, the movable mold attached to the movable platen is moved to the fixed mold attached to the fixed platen and guided to the predetermined injection start position, and both molds are moved. In a booster ram type mold clamping device in which the resin material in the molding cavity is compression-molded by injecting and filling the resin material in the molding cavity formed between the movable mold and the fixed mold. , Hydraulic fluid from the hydraulic pump is supplied to the booster cylinder chamber, and the main ram is driven by the hydraulic pressure of the booster cylinder chamber to close the movable mold. After moving the mold toward the high speed direction, the hydraulic oil from the hydraulic pump is supplied to the main cylinder chamber, and the main ram is driven by the hydraulic pressure of the main cylinder chamber to move the movable mold at the low speed type. By connecting the movable die to the injection start position and the main cylinder chamber by supplying hydraulic oil to the main cylinder chamber, the die is closed with respect to the main ram. Accumulating means for exerting a driving force in a direction, and a connecting line of the accumulating means to the main cylinder chamber for blocking the connecting line, and for injecting and filling the resin material into the molding cavity, the connecting line The hydraulic fluid from the hydraulic pump and the hydraulic fluid from the pressure accumulating means are both supplied to the main cylinder chamber, and the main ram is driven by the hydraulic pressure in the main cylinder chamber. First communication / cutoff means for clamping the movable mold, flow rate control means provided in a connection line of the pressure accumulating means to the main cylinder chamber, and connection of the pressure accumulating means to the main cylinder chamber. A booster ram type mold clamping device, comprising: a pressure control means provided on the line. 2. The line switching means switches to a low speed mold moving operation in the middle of a high speed mold moving operation of the movable mold in the mold closing direction to move the movable mold in the mold closing direction at a low speed. The booster ram type mold clamping device according to claim 1, which is adapted to lead to the injection start position. 3. The line switching means moves the movable mold in a mold closing direction at a high speed to guide it to a mold closing completion position, and then switches to a low speed mold moving operation to open the movable mold. The booster ram type mold clamping device according to claim 1, wherein the booster ram type mold clamping device is configured to move at a low speed in a direction to be guided to the injection start position. 4. A sequence valve is arranged in a main line connecting the hydraulic pump to the main cylinder chamber on the mold closing side, and a hydraulic pressure rise in a booster line connecting the hydraulic pump to the booster cylinder chamber. The hydraulic oil is supplied to the main cylinder chamber on the mold closing side by means of the sequence valve, and the booster line is connected to the main cylinder on the mold closing side by bypassing the sequence valve. A bypass line connecting to the room,
The second communication / blocking means for blocking the bypass line and for connecting the bypass line when switching from the high speed type movement to the low speed type movement is provided. The booster ram type clamping device described. 5. The connection line to the main cylinder chamber of the pressure accumulating means is cut off by the first communicating / cutting off means after the movable mold is moved to a compression completion position by the mold clamping operation. The booster ram type mold clamping device according to any one of claims 1 to 4, wherein the mold clamping holding pressure in the main cylinder chamber is maintained by supplying hydraulic oil from the hydraulic pump. 6. A booster ram is inserted into a main ram slidably arranged in the main cylinder chamber to form a booster cylinder chamber in the main ram, and a hydraulic pump is provided in the booster cylinder chamber and / or the main cylinder chamber. A booster ram type that allows the movable mold mounted on the movable platen to move toward and away from the fixed mold mounted on the fixed platen by supplying and discharging the hydraulic oil of After moving the movable mold with respect to the fixed mold using a mold clamping device and injecting and filling a resin material into a molding cavity formed between the two molds at a predetermined injection start position, the movable mold is moved. At the time of injection compression molding by pressing the mold and the fixed mold to compress the resin material in the molding cavity, hydraulic oil is supplied to the booster cylinder chamber to supply the booster cylinder. By driving the main ram by a hydraulic force of Sunda chamber,
After moving the movable mold at high speed in the mold closing direction, hydraulic oil is supplied to the main cylinder chamber and the main ram is driven by the hydraulic pressure of the main cylinder chamber to switch to low speed mold movement. After introducing the movable mold to the injection start position and injecting and filling the resin material into the molding cavity, a pressure accumulator is connected to the main cylinder chamber, and the pressure accumulation is performed together with the hydraulic pump in the main cylinder chamber. Injection hydraulic molding using a booster ram type mold clamping device characterized in that the mold clamping operation is performed by driving the main ram based on the oil pressure in the main cylinder chamber by supplying hydraulic oil from a container as well. Method.