JP3150646B2 - Mold clamping device of injection molding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold clamping apparatus for an injection molding machine which enables injection compression molding in which molding is performed by changing the clamping force in multiple stages.

[0002]

2. Description of the Related Art In an injection compression molding machine, it is sometimes necessary to compress a molten resin material injected into a mold cavity stepwise by moving a movable platen stepwise. As a mold clamping device for performing this, a branch pipe is connected in the middle of a pipeline connecting a hydraulic source to a mold clamping side oil chamber of a mold clamping cylinder, and an electromagnetic switching valve and a pressure control valve are provided in the branch pipe, A servo valve is provided upstream of the branch pipe of the pipeline (oil pressure source side), and a pilot check valve is provided downstream of the branch pipe of the pipeline (mold clamping cylinder side). Japanese Patent Application Laid-Open No. Hei 6 (1996) -1994 proposes a multistage compression of an injection resin material by switching valves.
No. 304985).

[0003]

The above-described mold clamping device for an injection molding machine has a problem that a hydraulic circuit and its control become complicated and that it cannot be added to an existing machine later. In addition, since the servo valve is used, it is difficult to manage the hydraulic oil and adjust the operation in order to maintain the stable and smooth operation.

[0004] One object of the present invention is to provide a mold clamping device for an injection molding machine, which has a simple structure of a hydraulic circuit and is easy to control, and also facilitates management and operation adjustment of hydraulic oil. SUMMARY OF THE INVENTION It is an object of the present invention to provide a mold clamping device for an injection molding machine in which an existing mold clamping device can be easily improved. Another object of the present invention is to provide a mold clamping device for an injection molding machine, which can stop a mold in a state where the mold is opened from a parting position precisely and minutely.

[0005]

In order to achieve at least one of the above-mentioned objects, a mold clamping device for an injection molding machine according to the present invention comprises a main passage provided with an electromagnetic switching valve, and a mold-side oil chamber and a rod. In a mold clamping device of an injection molding machine for moving a movable plate by moving a piston rod of a mold clamping cylinder in which a hydraulic pressure source is connected to a side oil chamber and clamping a mold between the movable plate and a fixed plate, An auxiliary cylinder whose piston is moved by a motor via a screw mechanism is provided such that its auxiliary oil chamber is connected to the mold-side oil chamber of the above-mentioned mold-clamping cylinder via a communication line.

In another aspect of the present invention, there is provided a mold clamping device for an injection molding machine, wherein a hydraulic source is connected to a mold clamping side oil chamber and a rod side oil chamber by a main conduit having an electromagnetic switching valve. In a mold clamping device of an injection molding machine for moving a movable plate by movement of a piston rod to clamp a mold between the movable plate and the fixed plate, the diameter of the mold clamping cylinder is larger than that of a mold clamping side oil chamber. The main pipe line is connected to the mold-side oil chamber side of the rod-side oil chamber, and a hydraulic pressure source is connected to an outer end of the rod-side oil chamber by an auxiliary pipe line having an auxiliary electromagnetic switching valve. An auxiliary oil chamber of an auxiliary cylinder, whose piston is moved by a motor through a screw mechanism, is connected to an outer end of the rod-side oil chamber via a communication pipe. Place the shuttle head between the main line and the auxiliary line, Fitted to Nroddo which was a configuration was charged so as to move freely with respect to the said piston rod and the rod-side oil chamber.

Further, according to another aspect of the present invention, there is provided a mold clamping device for an injection molding machine, wherein a hydraulic source is connected to a mold clamping side oil chamber and a rod side oil chamber by a main conduit having an electromagnetic switching valve. After the movable plate is moved by moving the piston rod to clamp the mold between the movable plate and the fixed plate, the resin injected by the injection device into the cavity of the mold is clamped to the mold. In a mold clamping device of an injection molding machine that compresses by increasing the force, an auxiliary cylinder whose piston is moved by a motor via a screw mechanism is connected to the auxiliary oil chamber to the mold clamping side oil chamber of the mold clamping cylinder. A control device is provided that communicates with a pipe and calculates a mold clamping force corresponding to the rotation amount of the motor when the resin is compressed, and controls the motor so that the mold clamping force becomes a set value. The configuration was adopted.

The piston rod of the mold clamping cylinder may be connected to a crosshead of a toggle mechanism for transmitting the moving force of the piston rod to a movable plate, or a rotation amount sensor provided on the motor to determine the rotation amount of the motor. The detection may be made by the following. Further, a configuration in which the piston rod of the mold clamping cylinder is coupled to the movable plate can be adopted.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described based on embodiments with reference to the drawings. 1 and 2 show an embodiment of a mold clamping device for an injection molding machine according to the present invention. Symbol 1 in the figure
Is a mold clamping cylinder. The mold clamping cylinder 1 is for moving the movable platen 3 along the tie bar 4 via the toggle mechanism 2 to clamp the molds 3a and 5a between the movable platen 3 and the fixed platen 5, and includes a piston rod. 1r is coupled to the crosshead 2a of the toggle mechanism 2 and fixed to the end plate 6. A plurality of tie bars 4 are provided with both ends fixed to a fixed plate 5 and an end plate 6 (only one is shown in the figure), and slidably support the movable plate 3.

Then, the mold-clamping-side oil chamber 1a of the mold-clamping cylinder 1
A hydraulic source 10 is connected to the rod-side oil chamber 1b by main pipelines 9a and 9b provided with an electromagnetic switching valve 8. The crosshead 2a is provided with a position sensor 11 for detecting the moving position of the crosshead 2a. Solenoid switching valve 8
Disconnects the main line 9a from the hydraulic source 10 at the neutral position, and connects the other main line 9b to the oil tank 12, and when the solenoid a is excited, connects the main line 9a to the hydraulic source 10 and The other main line 9b is connected to the oil tank 12, and when the solenoid b is excited, the main line 9a is connected to the oil tank 12 and the other main line 9b is connected to the hydraulic power source 10. . Reference numeral 14 denotes an injection device for injecting a molten resin into a mold cavity by bringing a nozzle of a heating cylinder into contact with the clamped molds 3a and 5a.

Reference numeral 20 denotes an auxiliary cylinder having an inner diameter smaller than that of the mold clamping cylinder 1. Auxiliary cylinder 20
Is fixed to a moving member 22 attached to a nut member 21 such as a ball nut, with its piston rod 20r
The auxiliary oil chamber 20a on the head side is provided so as to communicate with the mold-side oil chamber 1a of the mold-clamping cylinder 1 by a communication line 24. The nut member 21 is fixed in the axial direction by a motor 25 such as a servomotor or the like via a transmission mechanism 26 such as a gear, and is rotated at a fixed position by a screw shaft 27 such as a ball screw shaft.
The rotation of the screw shaft 27 by the electric motor 25 is moved in the axial direction of the screw shaft 27 to move the piston 20b of the auxiliary cylinder 20 via the moving member 22 and the piston rod 20r. I have. The motor 25 has a rotation amount sensor 29 such as a pulse encoder that detects a rotation amount of the motor and outputs a signal. The rotation amount of the electric motor 25 is determined by attaching a rotation amount sensor
The detection may be performed in anticipation of the reduction ratio of 6. The nut member 21 and the screw shaft 27 constitute a screw mechanism for converting a rotary motion into a linear motion. The amount of movement of the piston 20b moved by the electric motor 25 via a screw mechanism or the like and the amount of movement of the piston rod 1r (crosshead 2a) of the mold clamping cylinder 1 communicating with the auxiliary cylinder 20 are determined by the lead of the screw shaft 27 and the transmission mechanism 26. Is proportional to the rotation amount of the electric motor 25 with a fixed relationship determined by the reduction ratio of
9 can be detected.

A control device 31 for controlling the above-mentioned device includes a mold clamping force controller 31a, a mold clamping cylinder position controller 31b, an electromagnetic valve controller 31c, and a screw controller 31d. , Movable plate position sensor 1
1. A setter 3 for connecting the electromagnetic switching valve 8 and the screw position sensor 35 and setting various numerical values required for control.
0 is connected.

The clamping force controller 31a includes a servo amplifier 33
Is connected to the electric motor 25 through the
9, a mold clamping force and a toggle mechanism 2 set in various data setting units 30c of the setting unit 30 in response to the rotation amount signal r detected by the setting unit 30.
Indicating the relationship with the position of the crosshead 2a, the lead of the screw shaft 27, the reduction ratio of the transmission mechanism and the crosshead 2a.
From the data indicating the relationship between the position of the motor 25 and the amount of rotation of the motor 25, a mold clamping force corresponding to the amount of rotation of the motor 25 is calculated, and the mold clamping force is set in multiple steps in the mold clamping force setting device 30a. After the control signal (rotation amount signal) is output to the servo amplifier 33 to rotate the motor 25 so that the predetermined setting value is obtained, the predetermined setting time set in the mold clamping force holding timer 30b that can be set in multiple stages is set. Only the motor 25 is stopped and the motor 25 is operated so as to maintain the mold clamping force.

The mold clamping cylinder position controller 31b receives the position signal detected by the movable platen position sensor 11, detects that the movable platen 3a has reached a predetermined position, and sends a control signal to the solenoid valve controller 31c. The electromagnetic switching valve controller 31c switches the electromagnetic switching valve 8 via the output unit 34, switches the electromagnetic switching valve (not shown) for the injection cylinder of the injection device 14, and controls the mold clamping force controller. 31a to send a control signal,
The electric motor 25 stops at the clamping end position of the movable platen 3. The screw controller 31d receives the position signal y from the screw position sensor 35, and when the screw of the injection device 14 reaches the set value set in the screw position setter 30e, the screw controller 31d sets the screw in the mold clamping delay time setter 30d. After a time, a control signal is sent to the mold clamping force controller 31a, and the motor 25
To rotate.

By the way, the position of the crosshead 2a and the mold clamping force have a relationship as shown in FIG. 4, for example, and the position of the crosshead 2a and the rotation amount of the electric motor 25 are as shown in FIG.
Is proportional to Therefore, control device 31 calculates the position of crosshead 2a and the amount of rotation of electric motor 25 based on FIGS. In FIG. 4, P1 is a position where the molds 3a and 5a are aligned, and PE is a stroke end (mold clamping completion) position of the mold clamping cylinder 1.

The comparison circuit 32 of the servo amplifier 33
Compares the control signal from the mold clamping force controller 31a of the control device 31 with the detection signal of the rotation amount sensor 29, and the detection signal of the rotation amount sensor 29 matches the control signal of the mold clamping force controller 31a. By the way, the output to the drive command section 33a is stopped to stop the electric motor 25. By such feedback control, the piston 20 of the auxiliary cylinder 20
b, and thus the crosshead 2a is accurately stopped at the set position.

Next, the operation of the mold clamping device of the injection molding machine having the above configuration will be described. In the mold opening state, when the solenoid a of the electromagnetic switching valve 8 is excited by the mold closing command, the hydraulic oil of the hydraulic power source 10 passes through the main line 9a at the low mold closing pressure set by the mold clamping force setting device 30a. Since it flows into the mold-clamping-side oil chamber 1a of the mold-clamping cylinder 1 and moves the piston rod 1r to the right in the drawing, the movable platen 3 moves to the right via the toggle mechanism 2, and the mold 3a and the fixed platen 5 are moved. Is performed in which the mold 5a is matched with the parting surface on the parting surface (SP1).

At this time, the position of the crosshead 2a is detected by the movable platen position sensor 11, and the position of the crosshead 2a where the parting surfaces of the dies 3a and 5a meet (parting position (see FIG. 4), the movable platen 3 stops with almost no mold clamping force applied. When the mold closed state is reached, the position signal x from the movable platen position sensor 11 is transmitted to the mold clamping cylinder position controller 31.
b receives the signal and sends the signal to the solenoid valve controller 31d. The solenoid valve controller 31d instructs the output unit 34 to demagnetize the solenoid a of the solenoid-operated switching valve 8 (SP2).
The molten resin is injected into the cavity a by the forward movement of the injection screw from the injection device 14 (SP3). When the cavity is filled with the molten resin, the tie bar is extended by the pressure of the resin, and the parting surfaces of the molds 3a and 5a are opened, so that compression allowance of the resin occurs.

The injection screw is a screw position setting device 30e.
Screw controller 31d that has advanced to a preset position in from is detected by the position signal y from the screw position sensor 35, the predetermined time set in the mold clamping delay time setting unit 30d counts up (SP4 ), A signal is sent from the screw controller 31d to the mold clamping force controller 31a,
The electric motor 25 is rotated, and the operation of the electric motor 25 causes the screw shaft 27 to rotate.
Is rotated and the auxiliary cylinder 20 together with the nut member 21 is rotated.
When the movable platen is closed, the piston rod 20r and the piston 20b are moved rightward from the position retracted to the left end in FIG. 1 by the hydraulic pressure in the main pipeline 9a (SP5). As a result, the hydraulic oil in the auxiliary oil chamber 20a of the auxiliary cylinder 20 passes through the communication pipe 24 and the main pipe 9a, and the clamping cylinder 1
And the piston rod 1r is moved to the right, so that the molds 3a and 5a whose parting surfaces are open for the compression allowance are clamped by the increased mold clamping force.
At this time, the position of the crosshead is determined by the position signal x from the movable platen position sensor 11 to the mold clamping cylinder position controller 31b.
Is detected and commanded to the mold clamping force controller 31a, so that the mold clamping force controller 31a reads a signal from the rotation amount sensor 29 of the electric motor 25 (SP6), and rotates based on the relationship shown in FIGS. The mold clamping force corresponding to the amount r is calculated, and it is determined whether or not this mold clamping force has reached the first-stage mold clamping force set in the mold clamping force setting device 30b (SP7). It is determined whether the mold clamping force is the one set at the last stage (SP
8) If it is not the last stage, the motor 25 is stopped and held for the time set in the mold clamping force holding timer setting unit 30b for the first stage mold clamping force (SP9). The mold clamping force set value of the next stage is read, and the mold re-clamping is commanded (SP10).

In this manner, the molds 3a, 5a
Is clamped to compress the resin. When the final stage of the mold clamping force reaches the set value, the mold clamping cylinder position controller 31b receives the position signal x from the movable platen position sensor 11 and switches to the mold clamping force controller 31a and the solenoid valve controller 31c. The command signal is sent, and the mold clamping force controller 31a stops the electric motor 25 via the servo amplifier 33, so that the multi-stage mold clamping operation in the injection compression molding is completed. When a predetermined time has elapsed since the end of the mold clamping operation, the electromagnetic valve controller 31c outputs the
4, a command i is issued, the solenoid b of the electromagnetic switching valve 8 is excited, pressure oil is sent to the rod side chamber 1b of the mold clamping cylinder 1, the movable platen 3 is opened, and a molded product is taken out. You.

Since the auxiliary cylinder 20 is operated by the electric motor 25, the piston rod 20r (piston 20b) of the auxiliary cylinder 20 can be accurately controlled and stopped at a predetermined position accurately. For this reason, the amount of oil supply of the mold clamping cylinder 1 to the mold clamping side oil chamber 1a can be accurately controlled, so that the position of the crosshead 2a can be controlled in multiple stages, and the mold clamping force in injection compression can be controlled in multiple stages. .

The auxiliary cylinder 20 is used to perform metal clamping of the molds 3a and 5a in addition to the above-mentioned method of clamping a mold having a parting surface opened with resin for a compression margin by increasing the mold clamping force in multiple stages. After the solenoid a of the electromagnetic switching valve 8 is turned off, the electric motor 25 is rotated in the reverse direction to move the piston rod 20r of the auxiliary cylinder 20 in the extension direction, and the piston 20b is retracted from the forward position, whereby the crosshead is moved. 2a is moved to the left in FIG.
After setting the compression allowance by opening the parting surface and injecting the resin into the mold cavity in this state, the resin can be compressed by controlling the mold clamping force in multiple stages. For this reason, it is possible to widely cope with the injection compression molding conditions. In this case, the electric motor 2 is also controlled by the control device 31.
The operation including the stop of 5 is controlled.

FIG. 6 shows another embodiment of the mold clamping device of the injection molding machine according to the present invention. In this mold clamping device, the rod-side oil chamber 1 b
Has a large diameter, a main pipe line 9b is connected to the rod-side oil chamber 1b on the side of the mold-clamping oil chamber 1a, and the rod-side oil chamber 1b
An oil pressure source 43 is connected to an outer end (an end on the movable platen 3 side) by an auxiliary pipeline 42 having an auxiliary electromagnetic switching valve 41.

When the solenoid a is excited, the auxiliary electromagnetic switching valve 41 connects the auxiliary line 42 to the oil tank 44 when the solenoid a is excited.
Further, when the solenoid b is excited, the auxiliary pipe 42 is connected to the hydraulic power source 43.

Further, at the outer end of the rod-side oil chamber 1b,
The auxiliary oil chamber 20 a of the auxiliary cylinder 20 is connected via a communication pipe 46. In addition, a shuttle head 47 is fitted and inserted into the piston rod 1r of the mold clamping cylinder 1 between the main pipeline 9b and the auxiliary pipeline 42 in the rod side oil chamber 1b. The shuttle head 47 has a piston rod 1r.
And the rod side oil chamber 1b. Since the other structure is the same as that of the mold clamping device of FIG. 1, the same reference numerals are given and the detailed description is omitted.

Next, the operation of the mold clamping device of the injection molding machine having the above configuration will be described. When the mold opening is completed, the solenoid b of the auxiliary electromagnetic switching valve 41 is excited to
Is sent to the outside of the shuttle head 47 (the right side in FIG. 6) of the rod-side oil chamber 1b of the mold clamping cylinder 1 via the auxiliary pipeline 42, and the shuttle head 47 is moved to the left end position in FIG. At this time, the electric motor 25 is operated to activate the auxiliary cylinder 2.
The 0 piston rod 20r is moved to the left end position in FIG.

Next, the solenoid b of the auxiliary electromagnetic switching valve 41 is demagnetized, and the solenoid a of the electromagnetic switching valve 8 is excited to move the piston rod 1r of the mold clamping cylinder 1 rightward in FIG. 47 to stop. At this time, the movable platen 3 is at a position separated by a predetermined distance from the position where the parting surfaces of the molds 3a and 5a are joined. Note that the solenoid a of the electromagnetic switching valve 8 is kept in the excited state. In this state, the electric motor 25 is operated to move the piston rod 20r of the auxiliary cylinder 20 to the right and stop at the set position.

By the above operation, the hydraulic oil outside the shuttle head 47 of the rod-side oil chamber 1b of the mold clamping cylinder 1 flows through the auxiliary pipe 42 and the communication pipe 46 to the auxiliary oil chamber 20a of the auxiliary cylinder 20. The shuttle head 47 moves to the right in FIG.
Moves to the right together with the shuttle head 47, and the movable platen 3 is moved to the mold 3a via the piston rod 1r.
The parting surface 5a is moved to a set position in which the parting surface is opened by a distance corresponding to the compression allowance of the resin, and the mold is closed.

In the above-mentioned mold closed state, the molten resin is moved forward by the injection screw from the injection device 14 so that the molten resin becomes the mold 3a, 5a.
Injected into the cavity. Then, the injection screw advances to a preset position, and after that, when the mold-clamping delay setter 30d counts up the set time, the motor 25
Moves the piston rod 20r of the auxiliary cylinder 20 rightward again by the set amount. Thereby, the mold clamping cylinder 1
Operates to move the piston rod 1r to the set position,
The mold clamping by the set mold clamping force of the first stage is completed.

Thereafter, the timer is stopped for the time set in the mold clamping force holding timer 30b, and when the time is up, the motor 25 is further operated to perform the mold clamping by the set clamping force of the second stage. This is repeated at the required stage to perform multi-stage injection compression molding, and after the piston rod 1r of the mold clamping cylinder 1 moves by the amount of the mold clamping, the mold clamping force of the final stage is reached and mold clamping is completed at the stroke end. . 6, the motor 25, the electromagnetic switching valve 8, and the auxiliary electromagnetic switching valve 41 are controlled by the control device 31 to set various values of the setting device 30, the rotation amount sensor 29, the movable platen position sensor 11, the screw It goes without saying that control is performed in substantially the same manner as in the embodiment shown in FIG. 1 based on a detection signal from the position sensor 35.

The same effects as those of the mold clamping device of FIG. 1 can be expected in the mold clamping device of FIG.

Each of the mold clamping devices shown in FIGS. 1 and 6 has a structure in which the movable platen 3 is moved by the mold clamping cylinder 1 via the toggle mechanism 2. The piston rod 1 r is connected to the movable platen 3. The present invention can also be applied to a direct pressure type mold clamping device in which the movable platen 3 is directly moved by the mold clamping cylinder 1. 1 and 6, the position of the crosshead 2a is detected by the position sensor 11, and the motor 2
Although the operation of the motor 5 is controlled, it is also possible to detect the mold clamping force from the pressure of the hydraulic circuit, the amount of elongation of the tie bar 4, and the like, and control the operation of the electric motor 25 with the mold clamping force.

Further, the screw mechanism shown in the drawing has a structure in which the nut member 21 is moved by the rotation of the screw shaft 27. However, the rotation of the nut member 21 at the fixed position by the electric motor 25 causes the non-rotation of the screw shaft 27. The piston rod 20r can be moved in the axial direction and the piston rod 20r can be moved together with the movement. A hydraulic pump, an accumulator, or the like is used for the hydraulic sources 10 and 43 as in the related art. However, in the mold clamping device of FIG. 6, the hydraulic sources 10 and 43 can be integrated. The hydraulic circuit is provided with a hydraulic device such as a relief valve as necessary, as in the related art.

[0034]

As described above, in the mold clamping device of the injection molding machine according to the present invention, the hydraulic source is connected to the mold clamping side oil chamber and the rod side oil chamber by the main pipeline having the electromagnetic switching valve. In a mold clamping device of an injection molding machine that moves a movable plate by moving a piston rod of a mold clamping cylinder to clamp a mold between the movable plate and a fixed plate, a piston is moved via a screw mechanism by an electric motor. The auxiliary cylinder is provided so that the auxiliary oil chamber is connected to the mold-side oil chamber of the mold-clamping cylinder by a communication line, and another mold-clamping device is provided for the mold-clamping cylinder. The main pipeline is connected to the mold-side oil chamber side of the rod-side oil chamber that has a larger diameter than the mold-side oil chamber,
An oil pressure source is connected to an outer end of the rod-side oil chamber by an auxiliary conduit having an auxiliary electromagnetic switching valve, and a piston is connected to an outer end of the rod-side oil chamber by a motor via a screw mechanism. The auxiliary oil chamber of the auxiliary cylinder is moved through a communication pipe, and the shuttle head is fitted to the piston rod of the mold clamping cylinder between the main pipe and the auxiliary pipe in the rod-side oil chamber. The piston rod and the rod-side oil chamber are movably inserted into the piston rod and the rod-side oil chamber. After the movable plate is moved by moving the piston rod of the mold clamping cylinder in which the oil pressure source is connected to the oil chamber, the mold is clamped between the movable plate and the fixed plate, and then injected into the cavity of the mold. The resin injected by the device is In a mold clamping device of an injection molding machine that compresses by increasing a mold clamping force, an auxiliary cylinder whose piston is moved via a screw mechanism by an electric motor has an auxiliary oil chamber in a mold clamping side oil chamber of the mold clamping cylinder. And a control device which is provided in communication with a communication pipe, calculates a mold clamping force corresponding to a rotation amount of the electric motor when the resin is compressed, and controls the electric motor so that the mold clamping force becomes a set value. Is provided, the following effects can be obtained.

(1) It is not necessary to provide a servo valve in the hydraulic circuit, and the configuration of the circuit is simple. Therefore, the management and operation adjustment of the hydraulic oil is easy, and the mold clamping force can be accurately controlled. Easy. (2) Basically, the hydraulic circuit of a conventionally used mold clamping device is simply connected to an auxiliary cylinder that is operated by a motor via a screw mechanism. The mold clamping device can be easily improved. (3) It is possible to accurately set the resin compression allowance to be performed by stopping the mold in a state in which the mold is accurately opened from the parting position by a minute amount, so that injection compression molding can be accurately performed.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of a mold clamping device of an injection molding machine according to the present invention.

FIG. 2 is a diagram illustrating an example of a control system of an electric motor.

FIG. 3 is a flowchart illustrating an example of an injection compression operation.

FIG. 4 is a diagram illustrating an example of a relationship between a crosshead position and a mold clamping force.

FIG. 5 is a diagram illustrating a relationship between a motor rotation amount and a crosshead position.

FIG. 6 is a view showing another embodiment of the mold clamping device of the injection molding machine according to the present invention.

[Explanation of symbols]

Reference Signs List 1 mold clamping cylinder 1a mold clamping side oil chamber 1b rod side oil chamber 1r piston rod 2 toggle mechanism 2a crosshead 3 movable plate 3a, 5a mold 5 fixed plate 8 electromagnetic switching valve 9a, 9b main pipeline 10, 43 hydraulic power source 11 Position sensor 20 Auxiliary cylinder 20a Auxiliary oil chamber 20r Piston rod 21 Nut member 24 Communication line 25 Electric motor 27 Screw shaft 29 Rotation amount sensor 31 Control device 41 Auxiliary electromagnetic switching valve 42 Auxiliary line 46 Communication line 47 Shuttle head

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-8-164529 (JP, A) JP-A 1-156029 (JP, A) JP-A 1-146721 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) B29C 45/64-45/68 B29C 45/76-45/82 B29C 33/20-33/28

Claims (6)

(57) [Claims] 1. A movable platen is moved by moving a piston rod of a mold-clamping cylinder in which a hydraulic source is connected to a mold-side oil chamber and a rod-side oil chamber by a main conduit having an electromagnetic switching valve. In a mold clamping device of an injection molding machine for clamping a mold with a fixed platen, an auxiliary cylinder whose piston is moved by a motor via a screw mechanism is used to clamp the auxiliary oil chamber to the mold clamping cylinder. A mold clamping device for an injection molding machine, which is provided in communication with a side oil chamber via a communication pipe. 2. A movable platen is moved by moving a piston rod of a mold clamping cylinder in which a hydraulic source is connected to a mold-side oil chamber and a rod-side oil chamber by a main conduit having an electromagnetic switching valve. In a mold clamping device of an injection molding machine for clamping a mold with a fixed platen, a rod-side oil chamber having a diameter larger than that of the mold-clamping cylinder of the mold-clamping cylinder is disposed on the mold-clamping-side oil chamber side. The main pipeline is connected, and a hydraulic pressure source is connected to an outer end of the rod-side oil chamber by an auxiliary pipeline having an auxiliary electromagnetic switching valve, and is connected to an outer end of the rod-side oil chamber. An auxiliary oil chamber of an auxiliary cylinder whose piston is moved by a motor via a screw mechanism is connected via a communication pipe, and a shuttle head is provided between the main pipe and the auxiliary pipe in the rod-side oil chamber. Fit to the piston rod of the mold clamping cylinder and An injection molding machine mold clamping device characterized by being charged so as to move freely with respect to the rod-side oil chamber. 3. The movable platen is moved by movement of a piston rod of a mold-clamping cylinder in which a hydraulic source is connected to a mold-side oil chamber and a rod-side oil chamber by a main conduit having an electromagnetic switching valve. After clamping the mold with the fixed platen, the mold clamping device of the injection molding machine compresses the resin injected by the injection device into the cavity of the mold by increasing the mold clamping force on the mold. In the above, an auxiliary cylinder whose piston is moved by a motor via a screw mechanism is provided by connecting the auxiliary oil chamber to a mold-side oil chamber of the mold-clamping cylinder by a communication pipe,
Injection molding, wherein a control device for calculating a mold clamping force corresponding to a rotation amount of the electric motor at the time of compressing the resin and controlling the electric motor so that the mold clamping force becomes a set value is provided. Machine clamping device. 4. A cross-head of a toggle mechanism for transmitting a moving force of the piston rod to a movable plate, wherein the piston rod of the mold clamping cylinder is coupled to the cross-head.
Or a mold clamping device for an injection molding machine according to 3. 5. The mold clamping device for an injection molding machine according to claim 3, wherein the rotation amount of the electric motor is detected by a rotation amount sensor provided in the electric motor. 6. The mold clamping device for an injection molding machine according to claim 1, wherein a piston rod of the mold clamping cylinder is coupled to a movable plate.