JPH09267372A - Injection molding machine - Google Patents

Abstract

(57) Abstract: In so-called high-pressure injection molding, the responsiveness of a movable mold is enhanced, and the reliability of pressure regulation and measurement is enhanced. In high-pressure injection molding, a movable mold 7 is opened by resin pressure when filling a mold with resin, and then a gate is closed while the mold clamping force is increased and the movable mold 7 is closed. As a result, the pressure is adjusted and measured, and the pressure and amount of the resin in the cavity 61 becomes constant. The fluid pressure drive device of the mold clamping device 1 has a two-stage configuration, and the rams at each stage have a booster ram mechanism configuration. The first ram 14 ensures a mold opening / closing stroke, and the second ram 14 is moved during pressure adjustment and metering. The total stroke of the second ram 14 is set to the minimum required. Thereby, the responsiveness of the movable die 7 is enhanced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding machine used in so-called high-pressure injection molding (in-mold metering compression molding), and more particularly to the structure of a mold clamping device.

[0002]

2. Description of the Related Art As described in, for example, JP-A-63-94808, in injection compression molding of a thermoplastic resin, a movable die is opened by resin pressure as the resin is filled in a cavity. In this method, the resin in the cavity is compressed by increasing the mold clamping force afterwards. This also applies to so-called high-pressure injection molding, which has recently been adopted. This high-pressure injection molding employs a mold structure in which the gate is closed during the final mold closing after the resin is filled in the cavity. Return the resin to the molding material feeder such as a heating cylinder,
The resin in the cavity is compressed after the gate is closed. In this way, the amount and pressure of the resin in the cavity at the time when the gate is closed are made constant by the process of opening the movable mold by the resin pressure and the process of returning the resin in the cavity to the molding material supply device side (measurement and To regulate).

In a conventional molding machine used for this type of molding, for example, a fixed mold and a movable mold are opened and closed by a direct pressure type mold clamping device having one hydraulically driven ram. . Therefore, although the stroke of the ram and the stroke of opening and closing the mold are equal, the total stroke must be large enough to take out the molded product at least when the mold is opened. The volume of the cylinder in which the piston of the ram is fitted also needs to have a size corresponding to the stroke.

[0004]

However, in the above-described conventional mold clamping device, since the fixed mold and the movable mold are opened and closed by one ram, the responsiveness of the ram operation is poor. That is, since the volume of the cylinder is large, the movement of oil into and out of this cylinder and the movement of the movable die do not respond quickly to each other, and the movable die does not open smoothly when the resin is filled, or when the die clamping force is increased. The movable type may not close immediately. For example, if the movable mold is not closed promptly, the resin in the mold becomes hard during that time, and the resin in the cavity may not be smoothly returned to the molding material supply device side. This will reduce the reliability of pressure regulation and metering.

Conventionally, a booster ram mechanism in which a booster ram is provided for the main ram has been used in order to shorten the opening / closing time of the mold, but such a booster ram mechanism also has the above-mentioned problem. It cannot be resolved.

In high-pressure injection molding, the amount of movement of the movable mold from the position when it is opened by the resin pressure to the final mold closing position is generally much smaller than the total stroke of opening and closing the mold. That is, the ram that opens and closes the mold over the entire stroke is not suitable for moving the movable mold for pressure regulation and metering in high-pressure injection molding.

On the other hand, it is an object of the present invention to enhance the responsiveness of the movable mold during high pressure injection molding and enhance the reliability of pressure regulation and measurement.

[0008]

SUMMARY OF THE INVENTION The present invention is directed to a fixed platen to which a fixed mold is attached, a movable platen to which a movable mold is attached, and a fluid pressure drive for opening and closing the movable platen with respect to the fixed platen. A mold clamping device having a device, and a molding material supplying device for filling a molding material into a cavity formed between the fixed mold and the movable mold, the molding material supplying device filling the cavity with the molding material. The movable side platen moves in a direction away from the fixed side platen along with the movement of the movable side platen, and the mold clamping device increases the mold clamping force after completion of the filling to move the movable side platen in a direction approaching the fixed side platen. It is an injection molding machine used for high pressure injection molding in which a gate from the molding material supply device to the cavity is closed. Further, in order to achieve the above object, the fluid pressure drive device includes a first cylinder in which a first cylinder chamber is formed and a first rod portion is built in the first cylinder chamber, A first ram slidably fitted into the first cylinder and slidably fitted to the outside of the first rod portion, wherein the first rod portion is provided with the first ram. A fluid inlet / outlet that communicates with the first cylinder chamber is provided, and one side and the other side of the piston portion of the first ram that is in contact with the peripheral wall portion communicates with the first cylinder chamber in the peripheral wall portion of the first cylinder. Provided with a fluid inlet and outlet,
A second cylinder which is provided at the tip of the first ram, forms a second cylinder chamber therein, and has a second rod portion built into the second cylinder chamber; A second ram slidably fitted to the outside of the second rod portion and slidably fitted to the outside of the second rod portion, the second rod portion being provided in the second cylinder chamber. A fluid inlet / outlet communicating therewith is provided, and the second wall is provided on the peripheral wall portion of the second cylinder on one side and the other side of the piston portion of the second ram which is in contact with the peripheral wall portion.
A fluid inlet / outlet communicating with the cylinder chamber of
By moving the second ram with respect to the cylinder, the movable platen moves when the molding material is filled in the cavity and the mold is clamped thereafter.

In the fluid pressure drive device of the mold clamping device,
The first ram is used to open and close the fixed mold and the movable mold, while the second ram moves the movable mold together with the movable platen during filling of the cavity with molding material and subsequent mold clamping. Used for. Both sets of cylinders and rams have a structure of a booster ram mechanism, and the ram moves rapidly when a fluid is put into the ram from the fluid inlet / outlet of the rod portion and pressure is applied. The mold clamping force is weak when pressure is applied to the ram from the fluid inlet / outlet of the rod portion, but the mold clamping force is increased by applying pressure from the fluid inlet / outlet of the peripheral wall of the cylinder.

At the time of molding, the movable side platen moves by the movement of the first ram to the limit position with respect to the first cylinder, and the fixed die and the movable die are closed.
Then, the molding material supplied from the molding material supply device is filled in the cavity formed between the fixed mold and the movable mold in a state where pressure is applied from the fluid inlet / outlet of the second rod portion into the second ram. . Along with that, the movable mold and the movable-side platen move in the direction away from the fixed mold due to the balance between the pressure of the molding material in the cavity and the pressure of the fluid applied to the second ram. The second ram moves with respect to the cylinder. Thus, the movable mold moves due to the balance between the pressure of the molding material and the mold clamping force, so that the pressure in the cavity becomes constant. Then, pressure is applied to the second ram from the fluid inlet / outlet of the peripheral wall of the second cylinder to strengthen the mold clamping force, whereby the second ram moves relative to the second cylinder, and the movable mold and the movable side are moved. The platen moves toward the fixed mold. Along with that, the molding material in the cavity returns to the molding material supply device side,
When the gate is closed, a certain amount of resin remains in the cavity under the above-mentioned constant pressure, and thereafter the molding material in the cavity is compressed. Further, after the molding material in the cavity is solidified, the first ram moves with respect to the first cylinder to move the movable platen, thereby opening the fixed mold and the movable mold, and molding the product. Taken out.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the injection molding machine of the present invention will be described below with reference to the drawings. The injection molding machine of the present embodiment is a vertical tightening type, and the upper and lower sides in the drawing match the actual upper and lower sides. The mold clamping device 1 includes a base plate 2
The fixed side platen 4 is fixed to the upper ends of the tie bars 3 provided upright at the four corners of the fixed side platen 4.
A movable side platen 5 located below is supported by the tie bar 3 so as to be vertically movable. Then, the fixed die 6 of the dies is attached to the lower surface of the fixed platen 4, and the movable die 7 of the dies is attached to the upper surface of the movable platen 5. The movable platen 5 is moved up and down by the drive of the direct pressure type fluid pressure drive device 11 to open and close with respect to the fixed platen 4.

Here, the structure of the fluid pressure drive device 11 will be described. The fluid pressure drive device 11 is basically a hydraulic cylinder device having a booster ram mechanism in a two-stage configuration. The first on the base plate 2
The cylinder 12 is provided, and the first rod portion 13 is erected from the bottom of the first cylinder chamber 12a in the first cylinder 12. And this first rod part
13 is slidably fitted vertically in a cylindrical first ram 14 whose upper surface is closed. In addition, a first piston portion 15 provided in a flange shape at the lower end portion of the first ram 14 has a first
Is vertically slidably fitted inside the peripheral wall of the cylinder 12. Further, the first ram 14 is the first cylinder
It penetrates through the upper wall of 12 and projects upward. Then, on the peripheral wall portion of the first cylinder 12, the first cylinder chamber 12a
Oil inlets / outlets 16, 17, and 18 which are fluid inlets / outlets communicating with the uppermost portion and the lowermost portion are formed. At the same time, the first rod portion 13 is formed with an oil inlet / outlet port 19 which is a fluid inlet / outlet opening to the upper end surface of the tip end thereof.

A second member is provided at the upper end of the first ram 14.
The cylinder 22 is provided, and the second rod portion 23 is erected from the bottom of the second cylinder chamber 22a in the second cylinder 22. A cylindrical second ram 24 having an upper surface closed is fitted on the outer side of the second rod portion 23 so as to be slidable in the vertical direction. Also, this second ram 24
A second piston portion 25, which is provided in a flange shape at the lower part of the above, is slidably fitted vertically inside the peripheral wall portion of the second cylinder 22. Further, the second ram 24 penetrates the upper wall portion of the second cylinder 22 and projects upward. Then, on the peripheral wall portion of the second cylinder 22, oil inlets / outlets 26, 27, 28 which are fluid inlets / outlets communicating with the uppermost portion and the lowermost portion of the second cylinder chamber 22a are formed. At the same time, the second rod portion 23 is formed with an oil inlet / outlet port 29 which is a fluid inlet / outlet opening at the upper end surface of the tip end thereof. The connection block 30 fixed on the second ram 24 is fixed to the movable platen 5.

The first ram 14 includes a fixed die 6 and a movable die 7.
Used to open and close. On the other hand, the second ram 24, together with the movable platen 5 and the movable mold 7 is filled with the thermoplastic resin as the molding material in the mold and the subsequent mold clamping in the step of high pressure injection molding described later in detail. It is used to move and has as many strokes as it needs. Therefore, the stroke of the second ram 24 is significantly smaller than the stroke of the first ram 14.

Next, the circuit configuration of the fluid pressure drive device 11 will be described with reference to FIG. The first drive circuit 31 that drives the first ram 14 and the second drive circuit 32 that drives the second ram 24 share the tank 33 and the pump 34,
Moreover, although they have the same structure, they are controlled independently of each other. Taking the first drive circuit 31 as an example,
First supply path 36 connected to tank 33 via pump 34
And a first return path 37 connected to the tank 33
It is connected to the stage switching valve 38. A first pressure regulating valve 39 is provided between the first supply passage 36 and the first return passage 37. Then, the first three-stage switching valve 38 is the first two-stage switching valve.
40, the first pre-feel valve 41 and the upper oil outlet / inlet 18 of the first cylinder 12. Further, the first two-stage switching valve 40 is connected to one oil inlet / outlet port 16 on the lower side of the first cylinder 12 and the oil inlet / outlet port 19 of the first rod portion 13. Further, the first pre-feel valve 41 is connected to the other oil inlet / outlet 17 on the lower side of the first cylinder 12. The second drive circuit 32 also has the same structure, and has a second supply path 46, a second return path 47, a second three-stage switching valve 48, a second pressure adjusting valve 49, and a second two. It has a stage switching valve 50 and a second pre-feel valve 51.

The changeover valves 38, 40, 48, 50 are used to connect the return passages 37, 47 to the oil inlets 18, 28 above the cylinders 12, 22.
When the oil inlets and outlets 19 and 29 of the rod portions 13 and 23 communicate with the supply passages 36 and 46, the oil that is a fluid flows into the rams 14 and 24 from the oil inlets and outlets 19, 29, and the rams 14, 24 rises. As a result, oil is introduced from the space above the piston parts 15 and 25 in the cylinders 12 and 22 to the oil inlet / outlet port 1
Return to the tank 33 through the 8, 28, 3 stage switching valves 38, 48. Further, one of the oil inlets / outlets 16 and 26 on the lower side of the cylinders 12 and 22 communicates with the return passages 37 and 47, but the space below the piston portions 15 and 25 in the cylinders 12 and 22 is Due to the negative pressure, oil flows from the tank 33 through the pre-feel valves 41, 51 and the other oil outlets 17, 27 on the lower side of the cylinders 12, 22. In this step, the rams 14 and 24 are raised by the pressure received on the upper surfaces of the rams 14 and 24 having a smaller pressure receiving area than the lower surfaces of the piston portions 15 and 25.

After that, the two-stage switching valves 40 and 50 are switched,
The oil passages 16 and 26 at one of the lower ends of the cylinders 12 and 22 communicate with the supply passages 36 and 46, and the oil passages 19 and 29 of the rod portions 13 and 23 are connected.
Communicates with the return paths 37 and 47. In this state, pressure is received by the lower surfaces of the piston portions 15 and 25 having a large area, so that a large mold clamping force can be obtained (pressurizing stroke). At this time, the pre-feel valves 41 and 51 prevent the reverse flow of oil from the space in the cylinders 12 and 22 below the piston portions 15 and 25.

On the other hand, by the switching valves 38, 40, 48, 50, the return ports 37, 47 are connected to the oil inlet / outlet ports 19, 29 of the rod portions 13, 23 and the oil inlet / outlet ports 16, 17, 26, below the cylinders 12, 22, respectively. When the oil passages 18 and 28 on the upper side of the cylinders 12 and 22 communicate with the supply passages 36 and 46 while communicating with 27, the oil passages 18 and 28 above the piston portions 15 and 25 in the cylinders 12 and 22 are communicated. Oil flows into the space and the rams 14 and 24 descend. Along with this, the oil in the spaces below the piston parts 15, 25 in the cylinders 12, 22 and in the rams 14, 24 returns to the tank 33 (return stroke).

A hydraulically driven ejector 56 is attached to the connecting block 30.

Next, the structure of the mold will be described. The fixed mold 6 and the movable mold 7 are opened and closed by the movement of the movable platen 5, and when the molds are closed, a product-shaped cavity 61 is formed between them. The fixed mold 6 includes a fixed side mounting plate 62 mounted on the fixed side platen 4 and a fixed side receiving plate fixed to a lower surface of the fixed side mounting plate 62.
63, and the fixed-side mounting plate 62 and the fixed-side receiving plate 63 form a base 64. Further, a locating ring 65 and a sprue bush 66 are fixed to the fixed side mounting plate 62. This sprue bush 66
Is connected to a nozzle 68 of a heating cylinder device 67 that is a molding material supply device of an injection molding machine, and has a sprue 69 that is a material passage inside, and a movable type that penetrates the fixed side receiving plate 63. It projects to the 7 side.

A movable plate 71, which is a movable body, is supported below the fixed side receiving plate 63 so as to be movable in a predetermined range in the vertical direction. For this support, although not shown, guide pins fixed to the fixed side mounting plate 62 and the fixed side receiving plate 63 and projecting downward penetrate the movable plate 71 slidably. Along with this, a stopper is provided below the fixed side receiving plate 63.
A sleeve 74 fixed by a bolt 73 together with 72 penetrates the moving plate 71 slidably. In addition, stopper 72
By moving the moving plate 71 from below.
The maximum opening amount between the 71 and the base 64 is regulated.
Further, the moving plate is moved by the spring 75 which is a biasing means sandwiched between the fixed side mounting plate 62 and the moving plate 71 in a compressed state.
71 is urged downward with respect to the base body 64. And
A tip portion of the sprue bush 66 is slidably fitted in a through hole 76 formed in the moving plate 71.

The base 64 has a fixed side mounting plate.
The pin 77 is fixed by being sandwiched between the fixed side receiving plate 63 and the fixed side receiving plate 63. The pin 77 penetrates the fixed side receiving plate 63 and projects downward, and the tip side of the pin 77 is a moving plate. It is slidably fitted in a through hole 78 formed in 71. And
A tip portion of the pin 77 forms a convex portion 79 that can project downward from the moving plate 71.

The movable die 7 has a movable side attachment plate 81 attached to the movable side platen 5 and a movable side die plate 82 fixed to the upper surface of the movable side attachment plate 81.
The movable side mold plate 82 abuts against the moving plate 71 and closes.
For mutual guidance of 71, this moving plate 71 has guide pins.
83 is fixed, and the guide pin 83 is
Is formed with a through hole 84 into which is slidably fitted. The movable side mold plate 64 is formed with a concave portion 86 into which the convex portion 79 of the fixed mold 6 is removably fitted. The final product-shaped cavity 61 is formed by the convex portion 79 and the concave portion 86. Also a closed moving plate
A runner 87 and a gate 88, which are material passages for communicating the sprue 69 with the cavity 61, are formed between the 71 and the movable side mold plate 82.

Although not shown, the movable die 7 is provided with an ejection mechanism which is driven by the ejection device 56 to release the molded product from the movable die 7.

Next, a high pressure injection molding method using the injection molding machine and the mold will be described. 1 shows the state when the mold is opened, but when the mold is closed, as shown in FIG.
First, the first ram 14 rises to the limit position. The first ram 14 is in the upper limit position until the mold is opened again thereafter. Along with this, the second ram 24 rises due to the rapid forward travel. As a result, the movable platen 5 is raised,
The movable side mold plate 82 and the moving plate 71 hit and close. However, since the hydraulic pressure applied to the second ram 24 is relatively weak during the rapid forward movement, the base 64 of the fixed mold 6 and the moving plate 71 are slightly open due to the balance between this hydraulic pressure and the force of the spring 75. Also, the second ram 24 is also in an intermediate position with respect to the second cylinder 22.

In this state, a molten thermoplastic resin as a molding material is injected from the heating cylinder device 67. This resin passes through sprue 69 and runner 87 to gate 88.
To fill the cavity 61 (filling step). In the case of an in-line screw type, for example, the resin is supplied from the heating cylinder device 67 until the screw reaches a predetermined position such as the forward limit. Along with this, as shown in FIG. 3, the movable die 7, the movable platen 5 and the second ram 24 are pushed down by the pressure of the resin in the cavity 61, and the opening amount between the base body 64 and the moving plate 71 is reduced. Expand from A1 at the time of mold closing to A2. The opening amount A2 is determined by the balance between the resin pressure in the cavity 61 and the force of the spring 75 and the hydraulic pressure applied to the second ram 24 during the rapid forward movement, and the more resin is filled in the cavity 61. growing. In other words, even if there is an error in the amount of resin supplied from the heating cylinder device 67, the error is absorbed by the change in the opening amount, and the pressure of the resin in the cavity 61 is adjusted and becomes constant (pressure adjustment). Process).

Thereafter, the second ram 24 of the fluid pressure drive device 11 is
Shifts to the pressurizing stroke, and the mold clamping force by the second ram 24 increases. As a result, the movable platen 5, the movable die 7, and the movable plate 71 ascend together with the second ram 24 and close to the base body 64. Along with that, the excess resin in the cavity 61 returns to the runner 87 from the gate 88 which is still open,
The resin in the mold returns to the heating cylinder device 67. Then, as shown in FIG. 4, when the opening amount between the base body 64 and the moving plate 71 decreases to A3, the convex portion 79 of the base body 64 of the fixed mold 6 starts to fit into the concave portion 86 of the movable mold 7. And the gate 88 closes,
At this point, a certain amount of resin remains in the cavity 61 (measurement step). Then, as shown in FIG.
The moving plate 71 and the moving plate 71 are closed until they abut each other, and accordingly, the resin in the cavity 61 is pressed and compressed (compressing step).

After the resin in the cavity 61 is sufficiently cooled and solidified, the second ram 24 and the first ram 14 are transferred to the second cylinder 22 and the first cylinder 12 as shown in FIG. The movable mold 7 is lowered together with the movable platen 5, and the mold is opened. With this mold opening,
The resin in the cavity 61, that is, the product and the resin solidified in the runner 87 and the sprue 69 first separate from the fixed mold 6. Then, using the ejector 56, the product and runner
87 and the resin solidified in the sprue 69 are ejected and separated from the movable mold 7. At the same time, a take-out device (not shown) takes out the product and the resin solidified in the runner 87 and the sprue 69 from the mold. Thereafter, the mold is closed again, and the above steps are repeated.

In order to prevent the operation of the take-out device from being hindered, the position of the movable die 7 at the time of taking out the product must be accurately maintained. For this purpose, for example, a mechanical stopper is provided and the die is provided. This can be dealt with by performing positioning when opened.

According to the high-pressure injection molding as described above, it is possible to obtain a high-precision product with stable quality by the pressure adjusting process and the measuring process. Moreover, since the density is increased by the compression step, a product excellent in mechanical properties and the like can be obtained.

Moreover, since the fluid pressure drive device 11 of the mold clamping device 1 has a two-stage structure of the first cylinder 12 and the first ram 14 and the second cylinder 22 and the second ram 24, Fixed type 6 and movable type 7 depending on the stroke of the ram 14
While the full stroke of opening and closing is ensured, the pressure adjustment process, the metering process, and the compression process are performed by the movement of the second ram 24 in which the total stroke is minimized. And the accuracy and reliability of pressure regulation and metering are improved. That is, since the volume inside the second cylinder 22 and the volume inside the second ram 24 are small, the movable mold 7 can be lowered quickly and accurately in accordance with the resin pressure in the cavity 61 during the pressure adjusting step. During the metering process, the second ram 24 is swiftly changed from the rapid forward stroke to the pressurizing stroke in response to the switching of the second two-stage switching valve 40, and the movable die 7 is quickly and accurately raised. it can. Therefore, the measuring step and the compressing step can be performed while the resin in the mold is still sufficiently soft.

Further, since the second ram 24 has the structure of the booster ram mechanism, compared with the case where the mold clamping force is switched by using a relief valve or the like in the hydraulic drive device, the movable mold 7
The responsiveness of is further improved, and the reliability of pressure regulation and metering is further enhanced.

Further, the mold clamping device 1 has a structure suitable for a vertical clamp type injection molding machine. By adopting the vertical clamp type, the mold precision is improved and various troubles due to continuous molding are reduced. You can also get the effect that you can.

Of course, the injection molding machine of this embodiment can be used for molding other than high-pressure injection molding, especially for general injection molding.

It should be noted that the present invention is not limited to the above embodiment, and various modifications can be made. For example,
Although the injection molding machine of the above-mentioned embodiment was a vertical tightening type,
The present invention can of course be applied to a lateral tightening type injection molding machine. Further, the moving plate in the mold apparatus of the above embodiment is necessary because the gate is a side gate, and is not essential for high pressure injection molding. For example, if the gate is a direct gate, The fixed type and the movable type may be integrated with each other.

[0036]

According to the present invention, in the injection molding machine used for high pressure injection molding, the fluid pressure driving device of the mold clamping device is the first cylinder and the first ram, the second cylinder and the second ram. And the second ram moves with respect to the second cylinder, so that the movable platen moves when the cavity is filled with the molding material and subsequently the mold is clamped. The responsiveness of the movable mold during filling and subsequent mold clamping is improved,
Increased reliability of pressure regulation and measurement. In addition, since the second rod portion having the fluid inlet / outlet at the tip end which is built in the second cylinder is slidably fitted in the second ram to form the booster ram mechanism, the movable type response is provided. Performance and reliability of pressure regulation and measurement are further enhanced.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of an injection molding machine of the present invention when a mold is opened.

FIG. 2 is a sectional view of the same filling step.

FIG. 3 is a cross-sectional view at the same time as the pressure adjusting step, in which (a) shows the molding machine and (b) shows the vicinity of the cavity.

FIG. 4 is a cross-sectional view of the same measuring step as above, where (a) shows a molding machine and (b) shows the vicinity of a cavity.

FIG. 5 is a cross-sectional view at the time of the compression step, in which (a) shows the molding machine and (b) shows the vicinity of the cavity.

FIG. 6 is a circuit diagram of the same fluid pressure drive device.

[Explanation of symbols]

 4 Fixed side platen 5 Movable side platen 6 Fixed type 7 Movable type 11 Fluid pressure drive device 12 First cylinder 12a First cylinder chamber 13 First rod part 14 First ram 15 Piston part 16 Oil inlet / outlet (fluid inlet / outlet) ) 17 Oil inlet / outlet (fluid inlet / outlet) 18 Oil inlet / outlet (fluid inlet / outlet) 19 Oil inlet / outlet (fluid inlet / outlet) 22 Second cylinder 22a Second cylinder chamber 23 Second rod portion 24 Second ram 25 Piston portion 26 Oil inlet / outlet (Fluid Port) 27 Oil Port (Fluid Port) 28 Oil Port (Fluid Port) 29 Oil Port (Fluid Port) 61 Cavity 67 Heating Cylinder Device (Molding Material Supply Device) 88 Gate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshinobu Takeda 1-3, Kogane-cho, Niigata City, Niigata Prefecture Mitsubishi Materials Co., Ltd. Niigata Plant

Claims (1)

[Claims] 1. A mold clamping device having a fixed platen to which a fixed mold is attached, a movable platen to which a movable mold is attached, and a fluid pressure drive device for opening and closing the movable platen with respect to the fixed platen. A molding material supplying device for filling a molding material into a cavity formed between the fixed mold and the movable mold, and the movable side platen is provided with the molding material supplying device filling the cavity with the molding material. It moves in a direction away from the fixed platen, and after completion of filling, the mold clamping device strengthens the mold clamping force and moves in a direction in which the movable platen approaches the fixed platen, and during this movement, from the molding material supply device. An injection molding machine used for high-pressure injection molding in which a gate to a cavity is closed, wherein the fluid pressure drive device forms a first cylinder chamber therein. A first cylinder having a first rod portion built into the first cylinder chamber, and slidably fitted in the first cylinder and slidable outside the first rod portion. And a first ram fitted to
The first rod portion is provided with a fluid inlet / outlet communicating with the first cylinder chamber, and the peripheral wall portion of the first cylinder has one side and the other side of the piston portion of the first ram in contact with the peripheral wall portion. Side is provided with a fluid inlet / outlet communicating with the first cylinder chamber, and is provided at a tip end portion of the first ram to form a second cylinder chamber therein and a second cylinder chamber is provided with a second cylinder chamber. A second cylinder containing a rod portion, and a second ram slidably fitted in the second cylinder and slidably fitted to the outside of the second rod portion. The second rod portion is provided with a fluid inlet / outlet communicating with the second cylinder chamber, and the peripheral wall portion of the second cylinder is provided with one side of the piston portion of the second ram in contact with the peripheral wall portion. Oh On the other side, a fluid inlet / outlet communicating with the second cylinder chamber is provided, and the second ram moves with respect to the second cylinder, thereby filling the cavity with the molding material and subsequently clamping the mold. An injection molding machine characterized in that the movable platen moves.