JP4371325B2 - Drive control device and drive control method for injection molding machine - Google Patents

Description

  The present invention belongs to the field of drive control technology for injection molding machines, and particularly relates to a drive control apparatus and drive control method for an injection molding machine driven by an electric motor.

As an example of a drive control device of a conventional injection molding machine, each ball screw shaft of two ball screw shafts is provided with a speed controller, and further provided with a position controller and a torque tuner for tuning the operation of each shaft, A system in which a parallel servo system that is not affected by the nonlinear friction of the ball screw mechanism is constructed is known (for example, see Patent Document 1 below).
Japanese Patent No. 3582722

  The technique shown in the above document is an effective method for obtaining a large output or thrust by driving a plurality of ball screws in parallel. In order to obtain a larger output, the number of axes is increased. This not only complicates the mechanism, but also reduces the cost merit.

  Also, when increasing the size by increasing the motor and ball screw of each axis without increasing the number of axes, the acceleration performance deteriorates due to the increase in the moment of inertia of the motor itself due to the increase in the size of the motor. Not only is it difficult to obtain important acceleration performance in a molding machine, but servo motors with a size exceeding several tens of kW have few applications in industrial machines and become expensive machines because they become special motors. End up.

  The present invention has been made to solve such a problem, and is newly applied to each ball screw shaft of a drive mechanism of an injection molding machine that drives a plurality of ball screw shafts in parallel by a servo system having a master-slave relationship. By configuring multiple servo motors with different master-slave relationships, injection performance with high acceleration performance, low cost and high reliability without complicating the drive mechanism, and capable of driving a large injection molding machine It is an object of the present invention to provide a drive control device and a drive control method for a machine.

  In order to solve the above-described problem, the present invention is configured such that one ball screw shaft is driven by two or more servomotors controlled by a master and slave relationship in the first master-slave relationship, and the first master-slave relationship is achieved. Control means for generating the same torque as that of the servo motor in the primary relationship in the first master-slave relationship, and driving each ball screw shaft. Of the servo motors in the master relationship in the master-slave relationship, one servo motor in the master relationship in the first master-slave relationship is between the servo motor in the master relationship in the other first master-slave relationship. The second master-slave relationship is different from the first master-slave relationship, and the servo motor in the slave relationship in the second master-slave relationship is the main motor-slave relationship in the second master-slave relationship. It is obtained so as to be constituted by the drive control device including a control means which is position control so as to follow the rotational position of the servo motor in engagement.

  According to the present invention, it is possible to obtain a large output by increasing the number of motors for one ball screw shaft without increasing the number of ball screw shafts. Large capacity is achieved with a simple configuration.

  That is, the present invention includes a mechanism in which a movable part is driven by at least two ball screw shafts, and in the drive control device or drive control method of an injection molding machine for obtaining the rotational force of the ball screw by a servo motor, the at least two ball screw shafts Is driven by two or more servo motors configured by the first master-slave relationship, and the servo motor in the master relationship in the first master-slave relationship determines the speed or position of the drive shaft. A detector for detecting, a torque command signal of a servo motor having a main relationship in the first master-slave relationship is formed based on a deviation between the detected speed and a given speed command, and the first master-slave is formed. Servo motors in the subordinate relationship in relation to the torque command signal of the main servomotor in the first master-subordinate relationship One of the servo motors in the main relationship in the first master-slave relationship that drives each ball screw shaft of the at least two ball screw shafts is the main relationship in the other first master-slave relationship. The servo motor in the second master-slave relationship is in a master relationship in the second master-slave relationship. Based on the deviation between the position detection signal of the servo motor and the position detection signal of the servo motor in the slave relationship in the second master-slave relationship, a position synchronization signal is formed to establish the slave relationship in the second master-slave relationship. In addition to the torque command signal of a certain servo motor, position synchronization is performed.

  Further, in the drive control apparatus or drive control method for an injection molding machine of the present invention, the servo motor in the slave relationship in the first master-slave relationship is provided with a detector for detecting the speed or position, and is detected by the detector. A position synchronization signal is formed based on a deviation between the detected position detection signal and the position detection signal of the servo motor in the primary relationship in the first master-slave relationship, and the slave relationship in the first master-slave relationship In addition to the torque command signal of the servo motor in the position, position synchronization is performed, and a braking control signal is formed on the basis of the position detection signal of the servo motor in the slave relationship in the first master-slave relationship. The brake control is performed in addition to the torque command signal of the servo motor in the slave relationship in the master-slave relationship.

  According to the present invention, the plurality of servo motors having the first master-slave relationship are configured for each ball screw of the drive mechanism that drives the plurality of ball screw shafts in parallel by the servo system having the second master-slave relationship. Even in a large drive device, high acceleration performance necessary for an injection molding machine can be obtained, and an inexpensive and highly reliable device can be obtained without complicating the drive mechanism.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing an overall configuration in an embodiment of the present invention.
FIG. 1 shows an example in which the present invention is applied to a drive mechanism for a mold clamping shaft. The drive sources are four main master servo motors 20, main slave servo motors 22, sub master servo motors 24, and sub slave servo motors 26. A control configuration in the case of a motor is shown.

  The cross head 44 which is a movable part is a cross head in a toggle type mold clamping device (not shown). The main master motor 20 of the main drive shaft rotates the drive pulley 30 and rotates the driven pulley 32 connected by the timing belt 33.

  The main slave motor 22 of the main drive shaft rotates the drive pulley 31 and rotates the driven pulley 32 connected by the timing belt 34. The driven pulley 32 is directly connected to the threaded portion of the ball screw 40 and rotates the threaded portion of the ball screw 40. The rotational force is converted into a thrust in the linear direction of the ball nut 41 of the ball screw 40 by the ball screw 40. The thrust generated in the ball nut 41 of the ball screw 40 becomes the thrust of the cross head 44.

  On the other hand, the sub-main motor 24 of the driven shaft rotates the driving pulley 35 and rotates the driven pulley 37 connected by the timing belt 38. The sub slave motor 26 rotates the driving pulley 36 and rotates the driven pulley 37 connected by the timing belt 39.

  The driven pulley 37 is directly connected to the threaded portion of the ball screw 42 and rotates the threaded portion of the ball screw 42. The rotational force is converted by the ball screw 42 into a thrust in the linear direction of the ball nut 43 of the ball screw 42. The thrust generated in the ball nut 43 of the ball screw 42 becomes the thrust of the cross head 44.

  That is, the mechanism is such that the thrust of the cross head 44 is obtained as the resultant force of the thrust generated by the two drive shafts. The controller is configured such that the command generation controller 1 outputs a speed command or a position command a that is a basic operation of the mold clamping shaft, and the servo controller 2 controls the servo motor in accordance with the command.

  The servo controller 2 includes a position detection signal j output from a pulse generator 21 attached to the main master motor 20, a position detection signal k output from a pulse generator 23 attached to the main slave motor 22, and a sub master motor 24. The position detection signal 1 output from the pulse generator 25 attached to the sub-slave motor 26 and the position detection signal m output from the pulse generator 27 attached to the sub-slave motor 26 are input, and the current detector (7, 8, 9, The current detection signals (f, g, h, i) output from 10) are input to the servo controller 2. In this embodiment, a pulse generator is used as the position detector, but it can be realized in the same manner by using a rotary encoder.

  The servo controller 2 controls the four servo motors (20, 22, 24, 26) according to those inputs (f, g, h, i, j, k, l, m) and the command a from the host. Is used to control the operation of the crosshead 44.

  The calculation results are output as voltage commands (b, c, d, e) of the voltage type inverters (3, 4, 5, 6) of the main master, main slave, sub master and sub slave, and the drive currents are output as E1 to E4. Is done.

  FIG. 2 shows a control block diagram of the servo controller 2 when the command a from the command generation controller 1 is a speed command.

  The speed of the main master motor 20 is controlled by the speed controller 50 using two signals: a speed command and a speed feedback from the main master motor 20. 53 is a speed signal processor. The output of the speed controller 50 becomes a current command of the main master motor 20, and is compared with the current detection signal of the main master motor 20 detected by the current detector 7 by the adder 51, and the current control is performed by the current controller 52.

  The main slave motor 22 is torque controlled by a current command from the main master motor 20. The current command of the main slave motor 22 is the same as the current command of the main slave motor 22, and is compared with the current detection signal of the main slave motor 22 detected by the current detector 8 by the adder 56 and is output by the current controller 57. The

  On the other hand, the same speed command as the speed command input to the main master motor 20 is input to the speed controller 59 on the sub side, and the speed is controlled by speed feedback from the sub main motor 24. 62 is a speed signal processor. The output of the speed controller 59 becomes a current command of the sub master motor 24, is compared with the current detection signal of the sub master motor 24 detected by the current detector 9 by the adder 60, and is current controlled by the current controller 61.

  The sub slave motor 26 is torque controlled by a current command from the sub master motor 24. The current command of the sub master motor 24 is the same as the current command of the sub slave motor 26, and is compared with the current detection signal of the sub slave motor 26 detected by the current detector 10 by the adder 65, and the current controller 66 outputs the current. Is done.

  Further, the position signal of the main master motor 20 and the position signal of the sub master motor 24 are compared by the adder 68, and the position controller 69 controls the position so that the positions of the main master motor 20 and the sub master motor 24 become equal. . The output of the position controller 69 is added to the current command of the sub master motor 24 by the adder 70 as a position synchronization control output. In FIG. 1, the servo controller 2 is shown as a concentrated unit, but each servo amplifier is configured with an individual servo controller, and signals necessary for realizing the operation of the block diagram of FIG. A configuration of transmitting by serial communication or parallel communication may be used.

Embodiment 2. FIG.
FIG. 3 is a block diagram showing Embodiment 2 of the present invention. In the configuration shown in FIG. 2, the position detectors (23, 27) are not used for the main slave motor 22 and the sub slave motor 26. However, like the configuration shown in FIG. The motor 26 is also provided with a position detector (23, 27) for detecting the rotational position information of the motor, and the rigidity of the mechanical coupling between the main master motor 20 and the main slave motor 22, or the sub master motor 24 and the sub slave motor. By using a position controller (54, 63) for the slave motor (22, 26) and a braking controller (71, 73) for suppressing vibrations when the mechanical coupling between the 26 is low, the machine It is possible to suppress performance deterioration due to the influence of rigidity and obtain more stable operation. Reference numerals 55, 58, 64, 67, 72 and 74 in the figure are adders.

  Various methods are conceivable as a method of configuring the braking controller (71, 73). As a simple method, there is a configuration using a PD (proportional / differential) controller as shown in FIG.

  In the present embodiment, the case where the present invention is applied to a driving device of a mold clamping device is shown. However, if the portion corresponding to the cross head 44 is applied to an operating portion that transmits the radiant power, the injection device is also configured in the same manner. can do.

It is a block diagram which shows schematic structure of the drive control apparatus of the injection molding machine which is embodiment of this invention. It is a control block diagram of the drive control apparatus of the injection molding machine in Embodiment 1 of this invention. It is a control block diagram of the drive control apparatus of the injection molding machine in Embodiment 2 of this invention. It is a block diagram which shows the structural example of PD controller which shows the braking controller in embodiment of this invention.

Explanation of symbols

  1 Command generation controller, 2 servo controllers, 3, 4, 5, 6 inverter, 7, 8, 9, 10 Current detector, 20 main master servo motor, 22 main slave servo motor, 24 sub master servo motor, 26 sub slave Servo motor, 21 main master pulse generator, 23 main slave pulse generator, 25 sub master pulse generator, 27 sub slave pulse generator, 30, 31, 35, 36 drive pulley, 33, 34, 38, 39 timing belt, 32, 37 Drive pulley, 40, 42 Ball screw, 41, 43 Ball nut, 44 Cross head, 50, 59 Speed controller, 51, 55, 56, 58, 60, 64, 65, 67, 68, 70, 72, 74 Adder , 52, 57, 61 , 66 Current controller, 53, 62 Speed signal processor, 54, 63, 69 Position controller, 71, 73 Braking controller, a, b, c, d, e, f, g, h, i, j, k, l, m signal lines, E1, E2, E3, E4 power lines.

Claims (4)

In a drive control device of an injection molding machine comprising a mechanism in which a movable part is driven by at least two ball screw shafts, and obtaining the rotational force of the ball screw by a servo motor,
One of the at least two ball screw shafts is driven by two or more servo motors configured by a first master-slave relationship, and the servo motor in the master relationship in the first master-slave relationship is driven. A detector for detecting the speed or position of the shaft is provided, and a torque command signal of a servo motor having a main relationship in the first master-slave relationship is formed based on a deviation between the detected speed and a given speed command. ,
The servo motor in the slave relationship in the first master-slave relationship is controlled by a torque command signal of the master servo motor in the first master-slave relationship,
Of the servo motors in the primary relationship in the first master-slave relationship that drives the ball screw shafts of the at least two ball screw shafts, one servo motor is the servo in the primary relationship in the other first master-slave relationship. A second master-slave relationship different from the first master-slave relationship with the motor;
The servo motor in the slave relationship in the second master-slave relationship includes the position detection signal of the servo motor in the master relationship in the second master-slave relationship and the position detection of the servo motor in the slave relationship in the second master-slave relationship. A drive for an injection molding machine characterized in that a position synchronization signal is formed based on a deviation from the signal and position synchronization is performed in addition to a torque command signal of a servo motor in a slave relationship in the second master-slave relationship Control device. In the drive control device of the injection molding machine according to claim 1,
The servo motor in the slave relationship in the first master-slave relationship is provided with a detector for detecting speed or position, and the position detection signal detected by the detector and the master relationship in the first master-slave relationship A position synchronization signal is formed based on a deviation from a position detection signal of a certain servo motor, and position synchronization is performed in addition to the torque command signal of the servo motor in a slave relationship in the first master-slave relationship, A braking control signal is formed based on the position detection signal of the servo motor in the slave relationship in the first master-slave relationship, and in addition to the torque command signal of the servo motor in the slave relationship in the first master-slave relationship A drive control device for an injection molding machine, characterized in that braking control is performed. In a drive control method of an injection molding machine having a mechanism in which a movable part is driven by at least two ball screw shafts and obtaining a rotational force of the ball screw by a servo motor,
One of the at least two ball screw shafts is driven by two or more servo motors configured by a first master-slave relationship, and the servo motor in the master relationship in the first master-slave relationship is driven. A detector for detecting the speed or position of the shaft is provided, and a torque command signal of a servo motor having a main relationship in the first master-slave relationship is formed based on a deviation between the detected speed and a given speed command. ,
The servo motor in the slave relationship in the first master-slave relationship is controlled by a torque command signal of the master servo motor in the first master-slave relationship,
Of the servo motors in the primary relationship in the first master-slave relationship that drives the ball screw shafts of the at least two ball screw shafts, one servo motor is the servo in the primary relationship in the other first master-slave relationship. A second master-slave relationship different from the first master-slave relationship with the motor;
The servo motor in the slave relationship in the second master-slave relationship includes the position detection signal of the servo motor in the master relationship in the second master-slave relationship and the position detection of the servo motor in the slave relationship in the second master-slave relationship. A drive for an injection molding machine characterized in that a position synchronization signal is formed based on a deviation from the signal and position synchronization is performed in addition to a torque command signal of a servo motor in a slave relationship in the second master-slave relationship Control method. In the drive control method of the injection molding machine according to claim 3,
The servo motor in the slave relationship in the first master-slave relationship is provided with a detector for detecting speed or position, and the position detection signal detected by the detector and the master relationship in the first master-slave relationship A position synchronization signal is formed based on a deviation from a position detection signal of a certain servo motor, and position synchronization is performed in addition to the torque command signal of the servo motor in a slave relationship in the first master-slave relationship, A braking control signal is formed based on the position detection signal of the servo motor in the slave relationship in the first master-slave relationship, and in addition to the torque command signal of the servo motor in the slave relationship in the first master-slave relationship A drive control method for an injection molding machine, wherein braking control is performed.

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