JP2001212855A - Drive apparatus for electromotive injection molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To move an injection screw or a movable platen by obtaining drive force of large capacity by smoothly connecting three or more electric motors to operate them. SOLUTION: The ball nuts 16 fixed to a pusher plate (movable member) 7 supported by guide rods 5 are screwed on the ball screws 13 of a pair of screw mechanisms 11 supported on the front and rear plates 3, 4 connected by the guide rods 5. The screw mechanisms 11 are synchronously operated by the electromotive servo motors (drive electromotors) 8, 8 fixed to the rear plate 4 through speed reducing transmissions 10, 10 each consisting of timing pulleys 12, 14 and a timing belt 15 and by an added electromotive servo motor (added electromotor) 20 through a synchronizing device 19 consisting of synchronizing timing pulleys 17, 21 and a synchronizing timing belt 18 to move the pusher plate 17 to move an injection screw 6 in its axial direction so as to allow the same to advance and retreat.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to electric injection molding in which a screw mechanism in which a nut is screwed onto a screw shaft is operated by an electric motor to drive a movable plate of a mold clamping unit or an injection screw of an injection unit forward and backward. The present invention relates to a driving device for a machine.

[0002]

2. Description of the Related Art Conventionally, as a driving device of an electric injection molding machine, one electric servomotor is directly connected to each of a pair of screw mechanisms for moving a pusher plate on which an injection screw of an injection unit is mounted (particularly, Fairness 4-736
No. 89) and a device in which the above-mentioned pair of screw mechanisms directly connected to one electric servomotor are connected to each other by a synchronous device using gears (Japanese Patent Application Laid-Open No. 62-128724).

[0003]

The drive device of the above-mentioned conventional electric injection molding machine drives the pusher plate by two electric servomotors, so that it is almost in comparison with the drive device driven by one electric servomotor. There is an advantage that a double driving force can be obtained and a corresponding capacity and pressure can be injected. However, 1
Since there is a limit to the maximum torque that can be obtained from two electric servomotors, a drive device that operates with two electric servomotors is required for high-power, high-pressure injection drive, which has been increasingly demanded recently. It is still insufficient, and it has been desired to realize a drive device for an electric injection molding machine that can meet the above demand.

[0004] The present invention has been made in view of the above points, and is intended to move a movable member such as a pusher plate or a movable plate with a large driving force by rationally combining three or more electric motors. It is an object of the present invention to provide a drive device of an electric injection molding machine that can perform the above. Another object of the present invention is to provide a drive device for an electric injection molding machine that can smoothly perform a connection operation of three or more electric motors.

[0005]

In order to achieve the above object, an object of the present invention is to provide an electric motor in which a movable member is driven by a plurality of screw mechanisms which are operated by a drive motor to convert a rotary motion into a linear motion. In the injection molding machine, each of the screw mechanisms is drive-coupled to one drive motor, and
They are communicated with each other via a synchronizer, and the synchronizer is configured to be drivingly connected to an additional electric motor.

In the apparatus having the above structure, when the driving motor and the additional motor rotate, the screw mechanism is operated via the synchronizing device to drive the movable members such as the pusher plate of the injection unit and the movable plate of the mold clamping unit. You. Thus, the injection of the molten resin is performed by the injection screw attached to the movable member, or the mold fixed to the movable plate and the fixed plate is clamped. According to the drive device, the drive motor and the additional motor rotate in synchronization with each other by the synchronization device, so that their drive forces are reasonably integrated, a large drive force is obtained, and a large capacity, high pressure injection and the like. , High-pressure mold clamping and the like are performed.

In the apparatus according to the first aspect, each screw mechanism is drivingly connected to the drive motor via a reduction gear transmission in which a transmission timing belt is wound around a transmission timing pulley attached to each of the screw mechanism and the drive motor. With this configuration (claim 2), the driving force of each drive motor is increased via the deceleration transmission device and is reliably transmitted to each screw mechanism, so that the movement of the movable member is independent of the load. It is performed smoothly.

[0008] In the apparatus according to the first or second aspect, the synchronization device is configured such that a synchronization timing belt is wound around a synchronization timing pulley attached to each screw mechanism (claim 3). It can be constituted by a plurality of meshed synchronous gears. Further, a synchronous timing belt can be wound around a synchronous timing pulley attached to each drive motor (claim 5). Further, in the device according to claim 3 or 5, the synchronization device may be configured such that a synchronization timing belt is wound around a timing pulley attached to the additional motor and is drivingly connected to the additional motor. (Claim 6).

Further, in the apparatus according to the present invention, a transmission timing belt is wound around a transmission timing pulley attached to any one of the synchronous gears and a transmission timing pulley attached to the additional motor. Thus, it is possible to adopt a configuration that is driven and connected to the additional electric motor (claim 7). According to these configurations, since the rotations of the drive motor and the additional motor are transmitted to each screw mechanism in synchronization with each other, the driving of the movable member is performed more smoothly.

In the apparatus according to any one of the first to seventh aspects, the movable member may be a pusher plate for moving the injection screw of the injection unit forward and backward (claim 8), or the movable member of the mold clamping unit. If it is a board, the drive by the large output of the injection screw and the movable board is performed smoothly.
Further, in the apparatus according to any one of the first to ninth aspects, the main drive control means for driving and controlling the additional electric motor, and the auxiliary drive means for driving the drive electric motor by torque control based on a torque command signal output from the main drive control means. With the configuration including the drive control means (claim 9), the rotation of the drive motor and the additional motor is synchronized accurately, and the movable member is smoothly moved by each screw mechanism.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described.
An example in which the present invention is applied to a driving device for moving an injection screw of an injection unit back and forth will be described with reference to the accompanying drawings. FIG.
2 and 1, reference numeral 1 denotes an injection unit in an electric injection molding machine. The injection unit 1 has a pusher plate (movable member) 7 in which an injection screw 6 is rotatably mounted on a pair of guide rods 5 integrally connecting a front plate 3 and a rear plate 4 to which the heating cylinder 2 is fixed.
Is supported movably in the axial direction of the injection screw 6, and the pusher plate 7 is driven by a pair of electric servomotors (drive motors) 8, 8 fixed to the rear plate 4 via a pair of reduction gear transmissions 10, 10. The molten resin is injected from the nozzle (not shown) of the heating cylinder 2 into the cavity of the mold by advancing and moving together with the injection screw 6 by the pair of screw mechanisms 11 and 11 which are respectively operated. Has become.

Each of the reduction gear transmissions 10 has a small-diameter transmission timing pulley 12 attached to the output shaft 8a of the electric servomotor 8 and a large-diameter transmission timing pulley 14 attached to the ball screw shaft 13 of the screw mechanism 11. And the transmission timing belt 15 is wound therearound.
Each of the screw mechanisms 11 includes a ball screw shaft 13 rotatably supported at both ends by a front plate 3 and a rear plate 4, and a ball nut fixed to the pusher plate 7 and screwed to the ball screw shaft 13. 16.

Synchronous timing pulleys 17, 17 are attached to the tip of the ball screw shaft 13 of each of the screw mechanisms 11, 11, and a synchronous timing belt 18 is wound around the synchronous timing pulleys 17, 17. The synchronous timing pulleys 17 and 17 and the synchronous timing belt 18 constitute a synchronous device 19 that synchronizes the operations of the pair of screw mechanisms 11 with each other. Further, the synchronization timing belt 18 of the synchronization device 19 is connected to an additional electric servomotor (additional electric motor) 20 attached to the rear plate 4.
Synchronous pulley 21 fixed to output shaft 20a
And a synchronizer 19 is drivingly connected to the additional electric servomotor 20, and the additional electric servomotor 20 and the electric servomotors 8, 8 operate the screw mechanisms 11, 11 in cooperation with each other. It has become.

The additional electric servomotor 20 can adjust the radial position of the output shaft 20a with respect to the rear plate 4 and adjust the tension of the synchronous timing belt 18. Also, in FIG.
Reference numeral a denotes an electric servomotor fixed to the pusher plate 7, which rotates the injection screw 6 via a gear transmission 6b.

Next, a control device A for controlling the driving of the electric servomotors 8, 8 and the additional electric servomotor 20 will be described with reference to FIGS. In FIG.
Reference numeral 50 denotes a motion controller (operation command means) for generating a command signal i for instructing the operation of the injection molding machine including the moving direction of the injection screw 6 of the injection unit 1, the injection speed, the injection pressure, the back pressure, and the like. The command signal i is sent to an amplifier (main drive control means) 51 via a signal line 52.
Is to be sent. Master servo amplifier 5
1 includes a PWM control circuit and an inverter (not shown), and the additional electric servomotor 20 based on a command signal i from the motion controller 50.
, A detection value e of a position detector 20a such as an encoder provided on the additional electric servomotor 20 is input, and the detection value e is used as a feedback amount to rotate the additional electric servomotor 20 (rotational position). Feedback control.

The master servo amplifier 51 includes a torque command calculator 51a. The master servo amplifier 51 determines the torque of the additional electric servomotor 20 according to the rating of the additional electric servomotor 20 and the command signal i output from the motion controller 50.
The output ratio when driving 0 is calculated. The ratio calculated by the torque command calculator 51a is converted into an analog signal (torque command signal) such as a sine wave. The frequency of the torque command signal indicates the rotation speed of the electric servomotor, and the amplitude indicates the magnitude of the torque.

Reference numerals 53, 53 denote slave servo amplifiers (slave drive control means), each of which has a PWM control circuit and an inverter similarly to the master servo amplifier 51, and a pair of signal lines from the master servo amplifier 51. Torque command signal input units 53a, 53 via 54, 55
It is configured such that a torque command signal t is input to a. Each of the command signal input sections 53a, 53a is connected to the switching speed of a transistor constituting an inverter provided in each of the slave servo amplifiers 53, 53 based on the input torque command signal, and to the electric servomotors 8, 8, The amount of current flowing is calculated, a control signal is output to a PWM control circuit provided in each of the slave servo amplifiers 53, 53, and the electric servomotors 8, 8 are driven at a predetermined output ratio. I have.

Further, as shown in FIG. 4, in the master servo amplifier 51, the additional electric servomotor 20 is connected to the position detector 20a by a position control loop LP.
The rotational position is controlled by feeding back the detection value e of the position detector 20 and the position detector 20 is controlled by the speed control loop LV.
The rotation speed is controlled by feeding back the rotation speed obtained by calculating from the detected value e of a, and the current flowing through the additional electric servomotor 20 is detected and fed back by the first torque control loop LC1. It is configured to be controlled.

Each of the slave servo amplifiers 53,
In 53, the electric servomotors 8 and 8 are controlled in rotation speed based on a control command of the rotation speed of the speed control loop LV in the master servo amplifier 51, and are controlled by the second torque control loops LC2 and LC2. The torque is controlled by detecting and feeding back a current flowing through each of the electric servomotors 8 and 8.

Next, the operation of the driving device of the injection molding machine configured as described above will be described. When the motion controller 50 of the control device A is operated, an operation command signal i is output to the master servo amplifier 51, and the master servo amplifier 51 detects the detection value of the position detector 20a with respect to the command position in the command signal i. e, the additional electric servomotor 8 is driven by the position feedback control, and the torque command calculation unit 51a of the master servo amplifier 51 calculates the torque command signal t and sends it to each of the slave servo amplifiers 53, 53. Output.

As a result, each slave servo amplifier 5
3, 53 torque command signal input units 53a, 53a calculate the switching speed of the transistor constituting the inverter from the frequency of the input torque command signal t, and calculate the electric servo motors 8, 8 from the amplitude of the torque command signal t. The amount of current flowing through the slave servo amplifiers 53 and 5 is calculated.
3 outputs a control signal to the PWM control circuit.
The inverter is operated by the M control circuit, and the electric servomotors 8, 8 are driven at the commanded speed and torque.

In this manner, each electric servomotor 8,
When the additional servomotor 8 and the additional electric servomotor 20 are operated, the rotation of each electric servomotor 8, 8 is transmitted to each screw mechanism 11, 11 via the deceleration transmission device 10, 10, respectively. Together with the injection screw 6, it moves forward or backward along the guide rods 5, 5 according to the rotation direction of the electric servomotors 8, 8, respectively. On this occasion,
The synchronizer 19 is a ball screw shaft 1 of each screw mechanism 11, 11.
The rotations of the motors 3 and 13 are mechanically synchronized with each other, and the torque of the additional electric servomotor 20 is added to the rotation and transmitted to the ball screw shafts 13 and 13.

In the above, the speed control of the electric servomotors 8 and 8 and the additional electric servomotor 20 is performed based on the speed command by the speed control loop LV in the master servo amplifier 51.
The torque control of 0 and the torque control of the electric servomotors 8 and 8 are performed independently in the master servo amplifier 51 and the slave servo amplifiers 53 and 53. There is an advantage that the rotation speed of the servomotor 20 does not differ and hunting can be prevented.

For this reason, the ball nuts 16, 16 of the screw mechanisms 11, 11 are accurately and synchronously moved without deviation from each other, so that the pusher plate 4 moves smoothly. As a result, the driving forces of the three electric servomotors 8, 8, and 20 are integrated to actuate the screw mechanisms 11 and 11 to move the injection screw 6 forward and backward. Using a servomotor, high-output injection drive can be performed, and the capacity and pressure of the injection unit can be increased.

In the above embodiment, the synchronization device 19
The synchronous timing belt 18 is wound around synchronous timing pulleys 17 attached to the ball screw shafts 13 of each screw mechanism 11, and the synchronous timing belt 18 is attached to the output shaft 20 a of the additional electric servomotor 20.
The synchronous device 19 is driven and connected to the additional electric servomotor 20 by being wound around the synchronous timing pulley 21 fixed to the
As shown in (1), the synchronizers 19a and 19b may be configured, and these may be drivingly connected to the additional electric servomotor 20. The injection unit 1 shown in FIGS.
In FIGS. 1A and 1B, the same components as those of the injection unit 1 of FIGS. 1 and 2 are denoted by the same reference numerals.

That is, the one shown in FIG.
9a is a ball screw shaft 13, 1 of each screw mechanism 11, 11.
3 is meshed with another synchronous gear 24 rotatably attached to the rear plate 4 by a support shaft 23. And
A transmission timing pulley 25 integrally connected to the other synchronous gear 24 and rotatably supported by the support shaft 23.
And a transmission timing pulley 2 fixed to the output shaft 20a of the additional electric servomotor 20 fixed to the rear plate 4.
A transmission timing belt 26 is wound around the transmission timing belt 1a. In the above, the other synchronous gear 24 is connected to the output shaft 20a of the additional electric servomotor 20 without passing through the reduction gear transmission 10a in which the transmission timing belt 26 is wound around the transmission timing pulley 25 and the transmission timing pulley 21a. It may be fixed.

FIG. 6 shows a synchronizer 19b.
Are the output shafts 8a, 8 of the main electric servomotors 8, 8, respectively.
a synchronous timing pulley 27, 2 attached to
7, a synchronous timing belt 28 is wound therearound. The synchronous timing belt 28 is wound around a transmission timing pulley 21 fixed to the output shaft of the additional electric servomotor 20 attached to the rear plate 4. The mounting position of the additional electric servomotor 20 can be adjusted in the radial direction of the output shaft so that the tension of the synchronous timing belt 28 can be adjusted.

In the case of the injection units 1a and 1b provided with the above-mentioned synchronizing devices 19a and 19b, the respective synchronizing devices 19a and 19b are also used.
b synchronizes the rotations of the ball screw shafts 13, 13 of the screw mechanisms 11, 11 (see FIG. 2) with each other, and adds the driving force of the additional electric servomotor 20 to the driving force of the electric servomotors 8, 8. Since the respective screw mechanisms 11 and 11 are operated, the same operation and effects as those of the injection unit 1 can be achieved. 6, the speed reducer 10
Before the output shaft 8a of the electric servomotor 8
Since the belt 9b is located, the length of the synchronous timing belt 28 can be reduced, and the required tension of the belt is reduced to extend its life and reduce tooth skipping.

In each of the injection units 1, 1a, and 1b, each screw mechanism 11 includes an electric servomotor 8 having a ball screw shaft 13 supported on the front plate 3 and the rear plate 4 and provided on the rear plate 4 side. As a result, the ball nut 16 fixed to the pusher plate 7 moves by rotating through the deceleration transmission 10. Instead, the ball nut 16 is supported by the front plate 3 or the rear plate 4. And the ball screw shaft 13 fixed to the pusher plate 7 may be configured to move. In this case, the same operation and effect as those of the above-described embodiment can be obtained. FIG. 7 shows an example in which the ball nut 16 is supported by the rear plate 4.

Further, the injection units 1, 1a, 1b
, Each of the electric servomotors 8, 8 provided on the rear plate 4, the reduction transmission 10, the synchronizers 19, 19a,
The pusher plate 7 is moved with respect to the front plate 3 by the operation of a drive device such as 19b, but instead of this, as shown in FIG.
May be omitted, and the driving device may be provided on the pusher plate 7. Also in this example, as shown in FIG. 9, the ball nut 16 rotatably supported by the pressure plate 7 may be rotated to move the pressure plate 7 via the ball screw shaft 13 fixed to the front plate 3. it can. In this case, the same operation and effect as those of the apparatus of the above embodiment can be obtained, and the structure can be simplified because the rear plate 4 is omitted.

In the injection unit 1a shown in FIG. 5, each of the synchronous gears 22, 22 of the synchronizing device 19a is replaced with each of the electric servomotors 8, 8, instead of the ball screw shafts 13, 13.
Attached to the output shafts 8a, 8a of the
, The operations of the screw mechanisms 11, 11 are mutually synchronized, and the driving forces of the electric servomotors 8, 8 and the additional electric servomotor 20 can be integrated.

Further, in the above embodiment, since the ball screw shaft 13 and the ball nut 16 are constituted by ball screws, the operation of the screw mechanism 11 is preferably performed extremely smoothly. You may comprise a square screw or a trapezoidal screw. In the above embodiment, the transmission timing pulleys 12, 14, 21a, 25 and the transmission timing belts 15, 26 constitute the reduction transmission 10, 10a, and the synchronous timing pulleys 17, 21, 27.
And the synchronization timing belts 18 and 28
9 and 19b, it is preferable because it is lightweight and has good transmission efficiency. However, these reduction transmissions 10 and 10a and the synchronizers 19 and 19b are not limited thereto, and the V pulley and V
It may be constituted by a belt or by other pulleys and a belt.

In the above embodiment, the synchronization device 1
One additional electric servomotor 20 is provided as an additional electric motor to which the drive 9, 19a, 19b is connected. However, the number of the additional electric motor is not limited to this, and two or more additional electric motors may be provided. The electric motor is connected to the synchronization devices 19, 19
By the synchronous operation of the control device A together with the operations of a and 19b, the synchronous operation with each of the drive motors 8 and 8 is performed favorably, and it is effective to drive the movable member smoothly and strongly. In this case, one of the plurality of additional motors is driven and controlled by the master servo amplifier 51, and the remaining ones are driven and controlled by the slave servo amplifier 53. Further, in the above embodiment, a pair of screw mechanisms 11 is provided, but three or more screw mechanisms 11 each driven by a drive motor may be provided.

In the above-described embodiment, the pusher plate 7 as a movable member for moving the injection screw 6 of the injection unit back and forth is driven by the screw mechanisms 11 of the drive unit. Instead of this, the movable plate as the movable member of the mold clamping unit may be moved forward and backward directly or via a toggle mechanism by the screw mechanism 11 to drive the mold opening / closing and the mold clamping drive. Further, an ejector plate as a movable member of the ejector device may be directly or indirectly driven. Also in this case, as in the driving device of the injection unit, the precise synchronous rotation of each screw mechanism 11, 11 and the electric servomotor (drive motor) 8, 8
In addition, the total driving force of the additional electric servomotor (additional electric motor) 20 allows each movable member to move smoothly, which can cope with an increase in capacity (increase in size) and an increase in pressure of the apparatus.

[0035]

As described above, the first aspect of the present invention is an electric injection molding machine in which a movable member is driven by a plurality of screw mechanisms which are operated by a drive motor to convert a rotational motion into a linear motion. Wherein each of the screw mechanisms is drivingly connected to one of the driving motors and connected to each other via a synchronizing device, and the synchronizing device is drivingly connected to the additional electric motor. I have. Therefore, according to the drive device, since the drive motor and the additional motor rotate in synchronization with each other by the synchronization device to operate the screw mechanism, the drive forces of the respective motors are reasonably integrated and a large drive force is obtained. As a result, the movable member can be moved smoothly, and the capacity and pressure of the device can be increased.

According to the second aspect of the present invention, the driving force of the driving motor is increased via the reduction gear transmission,
Since the power is reliably transmitted to each screw mechanism via the transmission timing pulley and the transmission timing belt, the movement of the movable member can be performed more smoothly by a strong driving force. According to the third and fourth aspects of the present invention, the rotation of the driving motor and the additional motor can be transmitted to the respective screw mechanisms in a precisely synchronized manner with a simple configuration. Control accuracy can be improved.

According to the fifth and sixth aspects of the present invention, since the synchronous timing pulley of the additional motor is drive-coupled to the synchronous timing belt, the synchronous timing pulley can be moved and adjusted to adjust the tension. Even without providing an idler pulley, the tension of the synchronous timing belt can be adjusted, and the configuration is simplified. Furthermore, according to the fifth aspect of the present invention, since the common synchronous timing belt is wound around the synchronous timing pulley of the driving motor and the additional electric motor, the rotations of these electric motors can be satisfactorily synchronized. The responsiveness of the rotation operation of each electric motor by the control means can be enhanced, and the responsiveness of the operation in the movement of the movable member can be improved.

According to the seventh aspect of the present invention, the transmission device in which the transmission timing belt is wound around the transmission timing pulley of the synchronous gear and the transmission timing pulley of the additional motor is used as a reduction transmission device, so that the additional motor can be used. The driving force can be increased, and the control accuracy of the movement of the movable member can be increased, as in the fourth aspect. According to the eighth and ninth aspects of the invention, the injection step of the injection unit and the movable plate of the mold clamping unit can be smoothly operated with a strong driving force.

According to the tenth aspect of the present invention, the main drive control means for controlling the driving of the additional electric motor, and the auxiliary drive for driving the drive motor by the torque control based on the torque command signal output from the main drive control means. With the configuration including the control means, the rotation of the drive motor and the additional motor can be accurately synchronized with each other, and therefore, the movable member can be moved by the respective screw mechanisms extremely smoothly.

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of the present invention.

FIG. 2 is an exploded plan view partially showing the same in cross section.

FIG. 3 is a block diagram of a control device.

FIG. 4 is a block diagram of a main part of the control device.

FIG. 5 is a front view showing a second embodiment of the present invention.

FIG. 6 is a front view showing a third embodiment of the present invention.

FIG. 7 is an exploded plan view showing a fourth embodiment of the present invention.

FIG. 8 is a developed plan view showing a fifth embodiment of the present invention.

FIG. 9 is an exploded plan view showing a sixth embodiment of the present invention.

[Explanation of symbols]

Reference Signs List 1 injection unit 2 heating cylinder 3 front plate 4 rear plate 6 injection screw 7 pusher plate (movable member) 8 electric servomotor (drive motor) 10, 10a
Reduction transmission device 11 Screw mechanism 12, 14, 21a, 25 Transmission timing pulley 11 Ball screw shaft 15, 26 Transmission timing pulley 16 Ball nut 17, 21, 27 Synchronous timing pulley 18, 28 Synchronous timing belt 19, 19a,
19b Synchronous device 20 Additional electric servo motor (additional electric motor) 50 Motion controller (operation command means) 51 Master servo amplifier (main drive control means) 53 Slave servo amplifier (slave drive control means)

Continued on the front page (72) Inventor Yoshie Kaneko 1300 Okayama, Niigata City, Niigata Prefecture Inside Niigata Ironworks Niigata Seiki Factory (72) Inventor Katsuaki Yamada 1300 Okayama Niigata City Niigata Prefecture Niigata Ironworks Niigata Seiki Factory F term (reference) 4F206 AR087 AR11 AR16 JA07 JL02 JT01 JT03 JT32 JT33 JT37 JT38

Claims (10)

[Claims] 1. An electric injection molding machine driven by a plurality of screw mechanisms which are operated by a drive motor to convert rotary motion into linear motion, wherein each of said screw mechanisms is connected to one drive motor. A driving device for an electric injection molding machine, wherein the driving device is connected to each other via a synchronization device while being drivingly connected thereto, and the synchronization device is drivingly connected to an additional motor. 2. Each of the screw mechanisms is drivingly connected to the drive motor via a deceleration transmission device in which a transmission timing belt is wound around a transmission timing pulley attached to the screw mechanism and the drive motor, respectively. The driving device for an electric injection molding machine according to claim 1. 3. The electric motor according to claim 1, wherein the synchronization device has a configuration in which a synchronization timing belt is wound around a synchronization timing pulley attached to each screw mechanism. Drive device of the injection molding machine. 4. The drive device for an electric injection molding machine according to claim 1, wherein the synchronization device is constituted by a plurality of synchronization gears meshed with each other. 5. The electric injection molding machine according to claim 2, wherein the synchronization device has a configuration in which a synchronization timing belt is wound around a synchronization timing pulley attached to each of the drive motors. Drive. 6. The synchronous device according to claim 3, wherein the synchronous timing belt is wound around a synchronous timing pulley attached to the additional electric motor and is drivingly connected to the additional electric motor. 4. The driving device for an electric injection molding machine according to claim 1. 7. The synchronizer is configured such that a transmission timing belt is wound around a transmission timing pulley attached to any one of the synchronous gears and a transmission timing pulley attached to an additional electric motor, and is driven by the additional electric motor. The driving device for an electric injection molding machine according to claim 4, wherein the driving device is connected. 8. The electric injection molding machine according to claim 1, wherein the movable member is a pusher plate for moving an injection screw of the injection unit forward and backward. Drive. 9. The driving device for an electric injection molding machine according to claim 1, wherein the movable member is a movable plate of a mold clamping unit. 10. Main drive control means for controlling the drive of the additional motor, and auxiliary drive control means for driving the drive motor by torque control based on a torque command signal output from the main drive control means. The drive device for an electric injection molding machine according to any one of claims 1 to 9, wherein: