JP3237576B2 - Apparatus and method for controlling moving distance of mold opening of movable plate and injection compression molding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for controlling the amount of mold opening movement of a movable platen in an injection molding machine, and to an injection compression molding method.

[0002]

2. Description of the Related Art As an injection molding machine, as shown in FIG.
The movable platen 2 is moved to a predetermined molding position by the hydraulic cylinder 1 and the molds 4 and 5 are clamped between the fixed platen 3 and the fixed platen 3 at a low pressure. The injection of the resin into the molding cavity C is started, and the distance of the mold opening movement of the movable platen 2 due to the pressure of the resin injected into the molding cavity C is detected by the distance sensor 7 provided on the movable platen 2 and the fixed platen 3. When the movement amount reaches a preset compression allowance, filling is stopped, and the hydraulic cylinder 1
5 is re-clamped at high pressure to compress the resin in the molding cavity C (Japanese Patent Application Laid-Open No. 7-100888).

[0003] The movable platen 2 is slidably supported by a tie bar 9 provided between the fixed platen 3 and the end plate 8. The hydraulic cylinder 1 is fixed to an end plate 8, and a rod 1 b of a piston 1 a thereof is connected to the movable platen 2.

[0004]

In the above-mentioned conventional injection molding machine, the movable platen opening movement control device uses a very accurate distance sensor 7 such as a laser type or an eddy current type. The distance between the fixed plates 3 is measured, and the amount of mold opening movement of the movable platen 2 at the time of injection filling of the molding cavity C with the resin is controlled so as to be a set value as accurately as possible. However, since the fixed platen 3 is bent as shown by a two-dot chain line in FIG. 6 due to the mold clamping force of the hydraulic cylinder 1 and the nozzle pressing force of the injection device 6, the control accuracy is reduced and greatly fluctuates. For this reason, there is a problem that the molding control is adversely affected. FIG. 6 is exaggerated for easy understanding of the bending of the fixed platen 3.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an apparatus and a method for controlling the amount of mold opening movement of a movable plate capable of accurately controlling the amount of mold opening movement of the movable plate irrespective of the bending of the fixed plate. It is another object of the present invention to provide a movable platen mold opening moving amount control device and a control method capable of controlling the movable amount of mold opening movement of the movable plate with high accuracy using inexpensive control means.

Another object of the present invention is to provide an injection compression molding method capable of performing a good injection compression molding by controlling the amount of mold opening movement of a movable plate with high accuracy. Still another object of the present invention is to provide an injection compression molding method with good controllability.

[0007]

In order to achieve at least one of the above-mentioned objects, a movable platen mold opening moving amount detecting apparatus according to the present invention comprises a movable platen which is driven by a hydraulic cylinder as a driving source. In an injection molding machine that moves and clamps a mold between the movable platen and the fixed platen and injects and fills a molding cavity of the mold with a molten resin by an injection device, a mold-clamping-side oil chamber of the hydraulic cylinder is provided. In addition, the mold opening movement of the movable platen caused by the filling resin pressure at the time of injection filling of the resin into the molding cavity of the mold, the amount of mold opening movement of the movable platen by the hydraulic oil discharged from the mold-clamping-side oil chamber of the hydraulic cylinder. A hydraulic actuator having an actuating member actuated larger than
A connecting means is provided via an electromagnetic switching valve, and a detecting means for detecting that the operating member is operated by a set amount and the mold opening moving amount of the movable plate reaches a set value is provided.

In the above-described detection device, a plurality of hydraulic actuators can be connected in parallel to the mold-side oil chamber of the hydraulic cylinder, and each hydraulic actuator can be provided with an electromagnetic switching valve. Further, it is preferable that a pressure control valve for controlling the pressure of hydraulic oil flowing from the mold-side oil chamber to the actuating means be provided in a pipe connecting the hydraulic actuator to the mold-side oil chamber of the hydraulic cylinder. The hydraulic actuator can be an auxiliary cylinder having a smaller diameter than the hydraulic cylinder of the mold clamping device. Further, the detection means may be a detection switch operated by an operation member of the hydraulic actuator. The hydraulic actuator may be provided with setting means for variably setting the operation amount of the operation member. The setting means may be screwed to the hydraulic actuator so as to be movable in the operating direction of the operating member, and may be a stopper for regulating the operating position of the operating member. The setting means is a stopper which is attached to the hydraulic actuator, and which is moved and adjusted in the operation direction of the operation member by a rotation of the servomotor via a linear motion conversion mechanism formed by a nut and a screw, and regulates the operation position of the operation member. It may be.

Further, according to the present invention, there is provided a method for detecting the amount of mold opening movement of a movable platen in an injection molding machine provided with the control device having the above-described structure, in which the mold is opened by filling resin pressure into a molding cavity of a mold. The amount of mold opening movement of the moving movable platen is set by the operation amount of a hydraulic actuator that is operated by hydraulic oil discharged from the mold-clamping-side oil chamber of the hydraulic cylinder during the mold opening movement of the movable platen, and the movement of the movable platen Has reached the set value of the mold opening movement amount by the detecting means.

[0010] Further, the injection compression molding method according to the present invention comprises:
In the injection molding machine equipped with the control device having the above-described configuration, the injection molding device injects and fills the resin into the molding cavity of the mold clamped by the mold clamping device, and the movable platen is opened and moved by the pressure of the filled resin. Detecting means that the hydraulic actuator is actuated by the hydraulic oil discharged from the mold-side oil chamber of the hydraulic cylinder of the device, the actuating member is operated by a set amount, and the movable amount of the movable platen has reached the set value. Then, based on this detection signal, the hydraulic cylinder is operated to clamp the mold to compress the resin in the molding cavity.

In the above injection compression molding method, it is possible to adopt a configuration in which the mold opening movement amount of the movable platen is set by the movement of the piston of the auxiliary cylinder having a smaller diameter than the hydraulic cylinder.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described based on embodiments with reference to the drawings. FIG. 1 shows an embodiment of an apparatus for controlling the amount of opening movement of a movable platen according to the present invention. FIG.
The same reference numerals are given to the same members and the like, and the detailed description is omitted.

Pipes 12 and 13 having an electromagnetic switching valve 11 are connected to the mold-side oil chamber 1c and the mold-opening oil chamber 1d of the hydraulic cylinder 1, respectively. The electromagnetic switching valve 11 is provided by connecting pipes 12, 13 to a hydraulic source 14 such as a hydraulic pump and an oil tank 15 to four ports, respectively, and disconnects the hydraulic source 14 and the pipe 12 at a neutral position. When the pipe 13 is connected to the oil tank 15 and the solenoid a is excited, the pipe 12 is connected to the oil source 1 while the pipe 13 is connected to the oil tank 15.
4 and exciting the solenoid b, the piping 13
To the oil pressure source 14 and the piping 12 to the oil tank 1
5 is connected.

Reference numeral 17 denotes an auxiliary cylinder. The auxiliary cylinder 17 includes a head-side oil chamber 17c and a rod-side oil chamber 17d.
The pipes 19 and 20 each having an electromagnetic switching valve 18 are connected thereto, and a rod-side oil chamber 17 d is connected to one end of a pipe 22. When the solenoid a is excited, the pipe 22 is disconnected at the neutral position.
The hydraulic switch 1 has an electromagnetic switching valve 23 that opens the other end, and the other end is connected to the pipe 12 of the mold-side oil chamber 1 c of the hydraulic cylinder 1. The pipe 22 may be directly connected to the mold-side oil chamber 1c of the hydraulic cylinder 1. The inner diameter of the auxiliary cylinder 17 is smaller than the inner diameter of the hydraulic cylinder 1.

When the solenoid-operated switching valve 18 disconnects the pipe 20 from the hydraulic source 14a at the neutral position to connect the pipe 19 to the oil tank 15 and excites the solenoid a, the pipe 19 is connected to the hydraulic source 1
4a and the pipe 20 is connected to the oil tank 15.

On the head-side end wall of the auxiliary cylinder 17,
A stopper 25 having a screw structure is inserted into the auxiliary cylinder 17 with its tip end side and screwed forward and backward so as to be movable.
The movement stop position of the (operating member) can be adjusted. A dog 2 for operating detection switches 26 and 27 such as a limit switch and a proximity switch is provided at the tip of the piston rod 17b of the auxiliary cylinder 17.
8 is attached.

The detection switch 26 outputs a signal when the piston 17a of the auxiliary cylinder 17 contacts the stopper 25, and outputs a signal when the piston 17a reaches the forward limit. The relationship with the dog 28 is determined so as to output, and it is mounted together with the auxiliary cylinder 17 on a frame or the like of an injection molding machine. The positions of the detection switches 26 and 27 can be adjusted in the forward and backward directions of the dog 28. The position at which the piston 17a is retracted by the stopper 25 is determined by the amount of the mold opening movement (the moving distance of the movable platen from the mold closed position to the mold open position when the piston 1a of the hydraulic cylinder 1 retreats during injection filling of the resin into the molding cavity C). The moving position of the piston 17a is set to a value corresponding to the compression allowance of the resin). The auxiliary cylinder 17 constitutes an actuating means for actuating the mold opening movement of the movable platen with the hydraulic oil discharged from the mold clamping side oil chamber of the hydraulic cylinder 1, and the detection switch 26 sets the mold opening movement position of the movable platen. It constitutes detecting means for detecting. The hydraulic cylinder 1 constitutes driving means of the mold clamping device.

Next, the operation of the apparatus for controlling the amount of opening movement of the movable platen in the injection molding machine having the above configuration will be described. When the movable platen 2 is moved to the left in FIG. 1 to open the molds 4 and 5, the solenoid b of the electromagnetic switching valve 11 is changed from the state of FIG.
To excite. As a result, the hydraulic oil from the hydraulic source 14 flows into the mold opening side oil chamber 1d of the hydraulic cylinder 1 and pushes the piston 1a to the left.
The movable platen 2 retreats to the left, and the dies 4 and 5 are opened.

When the mold is to be clamped from the above-mentioned mold open state, the solenoid a of the electromagnetic switching valve 11 is excited. As a result, the hydraulic oil of the hydraulic pressure source 14 flows through the pipe 12 to the mold-clamping-side oil chamber 1c of the hydraulic cylinder 1, and the hydraulic oil of the mold-opening-side oil chamber 1d returns to the oil tank 15. 1
a moves forward and moves the movable platen 2 to clamp the molds 4 and 5 in a mold closed state where their parting surfaces are in contact. The mold clamping pressure at this time is usually set to a low pressure, the solenoid a is demagnetized, the electromagnetic switching valve 11 is set to the neutral position, and the movable platen 2 is stopped at a predetermined molding position.

By energizing the solenoid a of the electromagnetic switching valve 18 in parallel with the above operation, the operating oil of the hydraulic pressure source 14a is put into the head side oil chamber 17c, the auxiliary cylinder 17 is extended, and the piston 17a is moved forward. Move to. When the piston 17a reaches the forward limit, the detection switch 27 operates to output a signal, and after outputting this signal, the solenoid a of the electromagnetic switching valve 18 is demagnetized.

In the closed state of the mold, the injection device 6 is operated to inject and fill the molten resin into the molding cavities C of the dies 4 and 5. At an appropriate time from before the operation of the injection device 6 to immediately after the start of injection, the solenoid a of the electromagnetic switching valve 23 is excited to open the pipe 22, and the mold-side oil chamber 1 c of the hydraulic cylinder 1 is connected to the auxiliary cylinder by the pipes 12 and 22. 17 rod-side oil chambers 1
7d.

When the resin is filled in the molding cavity C and the resin is filled in the molding cavity C, the movable platen 2 is opened by the pressure of the filled resin and the piston 1 is moved.
a, the mold-clamping-side oil chamber 1c of the hydraulic cylinder 1
Hydraulic fluid flows into the rod-side oil chamber 17d of the auxiliary cylinder 17 as the piston 1a retreats, causing the piston 17a to retreat.

In this way, when the piston 17a of the auxiliary cylinder 17 is retracted from its forward limit position and abuts against the stopper 25 and stops, the mold of the movable platen 2 corresponding to the set value of the compression allowance of the resin in the molding cavity is set. The amount of opening movement is obtained, and at this time, a signal is issued from the detection switch 26. Immediately after the output of this signal, the solenoid a of the electromagnetic switching valve 23 is demagnetized. After a predetermined time, the operating oil pressure of the hydraulic pressure source 14 is switched from low pressure to high pressure, and the solenoid a of the electromagnetic switching valve 11 is changed.
After the molds 4 and 5 are re-clamped at a high pressure to compress the resin in the molding cavity C by the compression allowance, the solenoid a of the electromagnetic switching valve 11 is demagnetized. In general,
The timer is operated by the output signal of the detection switch 26,
Upon completion of counting by the timer, the solenoid a of the electromagnetic switching valve 11
To excite.

After the resin in the molding cavity C is solidified, the mold is opened as described above, and the molded product subjected to the injection compression molding is removed from the molding cavity C.

The hydraulic cylinder 1 is moved by the opening movement of the movable platen 2 which occurs when the resin is injected into the molding cavity C.
The inner diameter of the auxiliary cylinder 17 that is operated by the hydraulic oil discharged from the mold-clamping-side oil chamber 1c is smaller than the inner diameter of the hydraulic cylinder 1, and the piston 1a of the hydraulic cylinder 1
Since the retreat amount of the piston 17a of the auxiliary cylinder 17 is larger than the mold opening movement amount of the (movable platen 2), the resolution of the mold opening movement amount of the movable platen 2 is increased, and the setting accuracy is improved.

More specifically, for example, the hydraulic cylinder 1
In an injection molding machine with an inner diameter of 200 mm, the inner diameter is 40 mm
When the piston 1a of the hydraulic cylinder 1 moves by 1 mm when the auxiliary cylinder 17 of the
7a moves 25 mm, and the detection accuracy is increased 25 times. Moreover, even if the fixed platen 3 is bent by the mold clamping force or the nozzle pressing force, it is completely unrelated to this,
The detection accuracy is not impaired, and a constant accuracy can be always obtained without variation.

In re-clamping of the dies 4 and 5 at high pressure, the operating oil in the rod-side oil chamber 17d of the auxiliary cylinder 17 is fed to the mold-clamping-side oil chamber 1c of the hydraulic cylinder 1 by extending the auxiliary cylinder 17. You can also do it. Also, mold 4,
The re-clamping of 5 can be performed not only in one stage but in multiple stages. In this case, the re-clamping can be performed in the auxiliary cylinder 17 in one or more stages. When the mold is re-clamped by the auxiliary cylinder 17, the mold can be clamped with a higher pressure, and the trouble of returning the piston 17a of the auxiliary cylinder 17 to the forward limit can be omitted, and the workability is improved. The hydraulic pressure sources 14 and 14a may be integrated. The amount of mold opening movement of the movable platen 2 is set by changing and adjusting the amount of retreat of the piston 17a of the auxiliary cylinder 17 by moving and adjusting the stopper 25 in the axial direction.

FIG. 2 shows another embodiment of the apparatus for controlling the amount of opening movement of the movable platen according to the present invention. In this embodiment, a variable pressure control valve 30 is provided between the auxiliary cylinder 17 of the pipe 22 and the electromagnetic switching valve 23. The pressure control valve 30 controls the pressure of hydraulic oil flowing from the mold-side oil chamber 1 c of the hydraulic cylinder 1 to the rod-side oil chamber 17 d of the auxiliary cylinder 17.

In this embodiment, when the resin is injected and filled into the molding cavity C, the pressure control valve 30 applies a back pressure to the retreat of the piston 1a to prevent the movable platen 2 from abruptly opening the mold and perform compression molding. Can be performed well. Other configurations are the same as those in FIG.

FIG. 3 shows another embodiment of the movable platen opening moving amount control apparatus according to the present invention. In this embodiment, an auxiliary cylinder 17A having an inner diameter smaller than that of the auxiliary cylinder 17 is provided in parallel with the auxiliary cylinder 17, and an electromagnetic switching valve 23 is attached to each of the auxiliary cylinders 17 and 17A.

In this embodiment, an auxiliary cylinder 17 having a piston 17a that moves over the entire length of the cylinder,
By selecting one or more of 17A in combination with the switching state of each electromagnetic switching valve 23, 23, the mold opening movement amount of movable platen 2 can be set to three stages (large when auxiliary cylinders 17, 17A are selected, large In the case of only the auxiliary cylinder 17A, it can be set to medium, and in the case of only the auxiliary cylinder 17A, it can be set to small. For this reason, although the stopper 25 (FIG. 1) is not provided, the stopper 25 may be provided and practiced, so that the adjustment width of the mold opening movement amount can be further widened.

The number of auxiliary cylinders can be three or more. When three auxiliary cylinders 17 having different inner diameters are provided in parallel with each other, by selecting one or more of the auxiliary cylinders, the mold opening moving amount of the movable platen 2 can be changed to seven steps. Assuming that the ratio of the inner diameters of the three auxiliary cylinders is 1: 2: 4, an integral multiple of 1 to 7 based on the mold opening movement amount of the movable platen 2 when only the auxiliary cylinder having the minimum diameter is selected. This is convenient because adjustment is possible.

A pressure control valve 30 can be provided in the pipe 22 as shown in FIG.
Even if the pressure control valve 30 is provided on the pipe 22 of each of the auxiliary cylinders 17 and 17A, one pressure control valve 30 is provided on the common pipe 22 of each of the auxiliary cylinders 17 and 17A so that all the auxiliary cylinders 17 and 17A are provided. They can be shared. Some or all of the auxiliary cylinders provided in parallel with each other may have the same inner diameter. Other configurations are the same as those in FIG.

FIG. 4 shows still another embodiment of the movable platen mold opening moving amount control device according to the present invention. In this embodiment, instead of the stopper 25 in the embodiment shown in FIGS. 1 and 2, one end side is slidable in the axial direction in the auxiliary cylinder 17 as means for adjusting the movement stop position of the piston 17 a. And inserted so as not to rotate in the circumferential direction,
A stopper 25a provided with a ball screw 36 on the other end side is used. The stopper 25a is connected to a ball nut 37 screwed on a ball screw 36 via a required transmission mechanism 38 to a servomotor 35. When the servomotor 35 rotates, the ball nut 37 is transmitted via the transmission mechanism 38. Is rotated at a predetermined position fixed in the axial direction, and the stopper 25a screwed with the ball nut 37 moves in the axial direction to regulate the advance position of the piston 17a. The servomotor 35 is connected to a control device (not shown), and operates via a control device based on a command from a setting device such as an operation panel to set the movement position of the piston 17a corresponding to the compression allowance of the resin. Rotate to move the stopper 25a to the position. This rotation is detected by a rotation amount detector 35a provided in the servo motor 35 and feedback-controlled, so that the stopper 25a stops accurately at the set position.

In this embodiment, when the detection switch 26 detects that the piston 17a of the auxiliary cylinder 17 has retracted from the contact position with the stopper 25a to the inner end position of the auxiliary cylinder 17 on the piston rod 17b side. Then, the electromagnetic switching valve 23 is turned off, and after a predetermined time, the solenoid a of the electromagnetic switching valve 11 is excited to start high-pressure re-clamping. Other structures are the same as those in FIG. Therefore, according to this embodiment, the position of the stopper 25a is automatically adjusted, unlike the stopper 25, which needs to manually adjust the screwing position with respect to the auxiliary cylinder 17 in order to set the mold opening movement amount of the movable platen 2. It is easy to perform and operability is good.
The mechanism for adjusting the movement of the stopper 25a in the axial direction in this embodiment can be applied in place of the stopper 25 in the control device of the embodiment in FIGS.

In the embodiment shown in FIGS. 1 and 2, the piston 1
The forward position of the piston 17a is regulated by the rod-side end of the auxiliary cylinder 17, and the retracted position of the piston 17a is set and adjusted by the stopper 25. May be adjusted by the stopper 25. In this case, it goes without saying that the piston rod 17b is changed to the side opposite to the stopper 25. Similarly, in the embodiment of FIG. 4, the relationship between the arrangement of the stopper 25a and the piston rod may be reversed (the retreat position of the piston 17a is set and adjusted by the stopper 25a). In each of the above embodiments,
In each case, the linear auxiliary cylinder 17 is used as the operating means, but other rotary hydraulic actuators such as a swing type cylinder and a hydraulic motor can be used. Although the mold clamping device of each embodiment is of a direct pressure type, it may be a mold clamping device that moves the movable platen 2 via a toggle mechanism with a hydraulic cylinder. In each of the above embodiments,
A detection switch operated by the piston 17a of the auxiliary cylinders 17 and 17A is used as detection means for detecting that the operating member of the hydraulic actuator has operated the set amount and the mold opening movement amount of the movable plate has reached the set value. However, instead of this, the pipe 22 connecting the electromagnetic switching valve 18 and the electromagnetic valve 23 or the auxiliary cylinders 17, 1,
7A oil chamber 17d (when the pressure control valve 30 is provided in the pipe 22, the pipe 2 between the solenoid valve 23 and the pressure control valve 30
A pressure switch may be provided in 2) to detect that the hydraulic pressure acting on the auxiliary cylinders 17 and 17A from the hydraulic cylinder has risen to a predetermined value.

[0037]

As described above, since the apparatus and method for controlling the amount of opening movement of the movable plate according to the present invention have the above-described structure, the movable platen can be injected and filled with the resin into the molding cavity. The mold opening movement amount can be accurately set and controlled irrespective of the deflection of the fixed plate, and does not require expensive detection means such as a laser distance sensor. Therefore, a good molded product can be obtained by performing good molding control, and the cost can be reduced.

When a plurality of hydraulic actuators are connected in parallel to the mold-side oil chamber of the hydraulic cylinder and each hydraulic actuator is provided with an electromagnetic switching valve, by selecting a plurality of hydraulic actuators,
The amount of mold opening movement of the movable platen, that is, the compression allowance for re-clamping,
Settings can be changed easily and accurately.

Further, if a pressure control valve for controlling the pressure of hydraulic oil flowing from the mold-clamping-side oil chamber to the hydraulic actuator is provided in a pipe connecting the hydraulic actuator to the mold-clamping-side oil chamber of the hydraulic cylinder, Appropriate back pressure is applied to the opening movement of the movable platen during the injection filling of the resin into the molding cavity, whereby the movable platen can be prevented from suddenly moving with inertia, and compression molding can be performed favorably.

When the hydraulic actuator is an auxiliary cylinder having a smaller diameter than the hydraulic cylinder of the mold clamping device, the amount of movement of the auxiliary cylinder increases, the resolution of the amount of mold opening movement of the movable platen increases, and the setting accuracy increases. Improved, and because auxiliary cylinders are commonplace in hydraulic equipment,
The design is easy and the cost can be reduced.
Further, even when the detection means is a detection switch, the cost can be reduced. When the means for variably setting the operation amount of the operating member of the hydraulic actuator is a stopper screwed to the hydraulic actuator, the structure can be simple and easily implemented. If the variable setting means is a stopper that is moved and adjusted by a servo motor, the setting change of the mold opening movement amount of the movable plate can be automatically, quickly and accurately performed, and there is an advantage that the operation is easy.

Further, the injection compression molding method according to the present invention
In the injection molding machine equipped with the control device having the above-described configuration, the injection cavity is used to inject resin into the molding cavity of the mold clamped by the mold clamping device, and the movable platen is opened by the pressure of the filled resin. The hydraulic actuator was actuated with the hydraulic oil discharged from the mold-clamping-side oil chamber of the hydraulic cylinder of the mold-clamping device, and the actuating member was actuated by the set amount to reach the mold-opening movement amount of the movable platen. Is detected by the detection means, and based on this detection signal, the hydraulic cylinder is operated to close the mold to compress the resin in the molding cavity, so that the injection compression molding can be performed accurately regardless of the deflection of the fixed platen. And a good molded product can be obtained.

In this case, if the amount of mold opening movement of the movable platen is set by the movement of the piston of the auxiliary cylinder having a smaller diameter than the hydraulic cylinder of the mold clamping device, a good injection in which the resin allowance is set accurately. Compression molding can be performed.

[Brief description of the drawings]

FIG. 1 is a view showing an embodiment of a mold opening moving amount control device for a movable platen according to the present invention.

FIG. 2 is a diagram showing another embodiment of a movable platen mold opening moving amount control device according to the present invention.

FIG. 3 is a diagram showing another embodiment of the movable platen mold opening movement amount control device according to the present invention.

FIG. 4 is a view showing still another embodiment of the movable platen mold opening moving amount control device according to the present invention.

FIG. 5 is a diagram showing a conventional movable platen mold opening moving amount control device.

FIG. 6 is a view showing the bending of a fixed board.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Hydraulic cylinder 1a ... Piston 1c ... Mold clamping side oil chamber 1d ... Mold opening side oil chamber 2 ... Movable platen 3 ... Fixed platen 4, 5 ... Die 6 ... Injection device 14, 14a ... Hydraulic power source 17, 17A ... Auxiliary Cylinder 23 ... electromagnetic switching valve 26 ... detection switch (detection means) 30 ... pressure control valve C ... molding cavity

Claims (11)

(57) [Claims] 1. A movable plate is moved by a mold clamping device using a hydraulic cylinder as a drive source, a mold is clamped between the movable plate and the fixed plate, and molten resin is injected into a molding cavity of the mold. In the injection molding machine that performs injection filling by a device, the mold opening movement of the movable platen caused by the filling resin pressure at the time of injection filling of the resin into the molding cavity of the mold into the mold-side oil chamber of the hydraulic cylinder causes the mold of the hydraulic cylinder to enter. A hydraulic actuator having an operating member that is operated by the operating oil discharged from the tightening-side oil chamber to be larger than the mold opening movement amount of the movable plate is connected via an electromagnetic switching valve, and the operating member is operated by a set amount. And a detecting means for detecting that the movable amount of the movable plate has reached the set value. 2. The movable platen according to claim 1, wherein a plurality of hydraulic actuators are connected in parallel to the mold-side oil chamber of the hydraulic cylinder, and each hydraulic actuator is provided with an electromagnetic switching valve. Mold opening movement amount control device. 3. A pressure control valve for controlling a pressure of hydraulic oil flowing from said mold-clamping-side oil chamber to operating means is provided in a pipe connecting a hydraulic actuator to a mold-clamping-side oil chamber of a hydraulic cylinder. The moving amount control device for mold opening of a movable platen according to claim 1 or 2. 4. The control device according to claim 1, wherein the hydraulic actuator is an auxiliary cylinder having a smaller diameter than a hydraulic cylinder of the mold clamping device. . 5. The control device according to claim 1, wherein the detection means is a detection switch operated by an operation member of a hydraulic actuator. 6. The control device according to claim 1, wherein said hydraulic actuator is provided with setting means for variably setting an operation amount of said operation member. 7. The setting means, which is screwed to the hydraulic actuator so as to be movable in the operating direction of the operating member and is a stopper for regulating the operating position of the operating member. The movable amount control device for mold opening of the movable plate as described in the above. 8. The setting means is attached to the hydraulic actuator, and is moved and adjusted in the operating direction of the operating member by a rotation of a servomotor via a linear motion conversion mechanism including a nut and a screw, thereby regulating the operating position of the operating member. 7. The apparatus according to claim 6, which is a stopper for printing. 9. An injection molding machine provided with the control device according to claim 1, wherein the mold of the movable platen is moved by the pressure of the filling resin when the resin is injected into the molding cavity of the mold. Open travel distance
The movable platen is set by the amount of operation of the hydraulic actuator that is operated by the hydraulic oil discharged from the mold-clamping-side oil chamber of the hydraulic cylinder during the mold opening movement of the movable plate, and the movement of the movable plate reaches the set value of the mold opening movement amount. A moving amount of the movable platen, which is detected by the detecting means. 10. An injection molding machine provided with the control device according to claim 1, wherein a resin is injected and filled into the molding cavity of the mold clamped by the mold clamping device. When the movable platen opens due to the pressure of the filled resin, the hydraulic actuator is actuated by the hydraulic oil discharged from the mold-clamping-side oil chamber of the hydraulic cylinder of the mold-clamping device. An injection compression molding method, characterized in that the detection means detects that the mold opening movement amount has reached a set value, and based on the detection signal, the hydraulic cylinder is operated to perform mold clamping to compress the resin in the molding cavity. 11. The injection compression molding method according to claim 10, wherein the amount of mold opening movement of the movable platen is set by movement of a piston of an auxiliary cylinder having a smaller diameter than a hydraulic cylinder.