JPH0624753B2 - Motor control device for extrusion molding line - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a motor control device for an extrusion molding line, and more particularly to a plurality of extrusion molding lines in an extrusion molding line including an extrusion molding machine and used for plastic molding of long products and laminates. The present invention relates to an improvement of a motor control device suitable for controlling the rotation speed of a motor.

[Conventional technology]

An extrusion molding line that extrudes long products such as plastic pipes and laminates such as plastic sheets is configured by connecting a take-up machine to an extruder, for example, and extruding molten plastic raw materials with a screw using the extruder. In addition, the take-out machine takes the extruded product.

In such an extrusion molding line, in order to maintain a constant molding shape, it is necessary to set the number of rotations of the motor that rotates the screw of the extruder and the motor that is used to take the molded product in the take-up machine in a predetermined relationship. .

Furthermore, when changing the molding speed in the extrusion molding line or changing the composition of the extrusion molding line, it is necessary to change the rotation speeds of the motor of the extruder and the motor of the take-up machine under a predetermined speed command.

In order to issue such a motor speed command, for example, a motor speed control device is known in which the motors of the extruder and the take-up machine have the following relationship.

(1) A configuration in which the rotation speeds of the motor of the extruder and the motor of the take-off machine are independently controlled.

(2) A configuration in which the motor of the extruder is the main motor and the motor of the take-up machine is the sub motor, and the rotation speed of the sub motor is ratio-controlled at a predetermined ratio according to the rotation control of the main motor.

(3) A configuration in which the motor of the extruder is the slave motor and the motor of the take-up machine is the master motor, and the rotation speed of the slave motor is ratio-controlled at a predetermined ratio according to the rotation control of the master motor.

(4) A configuration in which the motors of the extruder and the take-up machine are each sub-motors, and the rotation speeds of the sub-motors are compared and controlled by a speed setter at a predetermined ratio.

Since the motors of the configuration (1) are independent of each other, the speed control does not affect each other, and the configurations (2) and (3) automatically control the ratio of the number of rotations of the sub motor by the main motor. Although possible, the main motor cannot be controlled by controlling only the sub motor.

Further, the configuration of (4) is characterized in that the motors of the extruder and the take-up machine are each controlled as a slave motor by a speed setter at a constant rotation ratio.

The speed command control of the motor of these extruders and take-up machines is
The independent operation and the ratio operation mode are appropriately selected according to the configuration of the extrusion molding line, the type of molded product, the molding speed, and the like.

[Problems to be Solved by the Invention]

However, in the conventional motor control device, the connection circuit configuration of each motor was changed to cope with the switching between the independent operation and the ratio operation mode. Therefore, when the mode is switched between the independent operation and the ratio operation mode, the switching is performed. There is a problem that a speed difference easily occurs between the front and rear motors, and from the viewpoint of stable extrusion molding operation, there is a demand for a device that does not change the rotation speed of each motor before and after the mode switching.

In particular, when the modes are frequently changed, there is a problem that the reproducibility of the ratio operation of each motor is deteriorated when the independent operation mode is changed to the ratio operation mode.

The present invention has been made under such circumstances, and an object of the present invention is to provide a motor control device in which a motor speed difference does not occur even when the motor speed command mode of an extrusion molding line is switched between a single operation mode and a ratio operation mode. And

[Means for Solving the Problems]

In order to solve such a problem, according to the present invention, as shown in the claim correspondence diagram of FIG. 1, a plurality of motors 100 arranged in an extrusion molding line including an extrusion molding machine, a rotation speed setting means 101, a rotation speed. Measuring means 102, master-slave relationship setting means 1
03, mode switching means 104, line speed setting means 10
5, the control means 106 and the speed command means 107 are provided.

The rotation speed setting means 101 sets the rotation speeds of the plurality of motors 100, and the rotation speed measuring means 102 sets the rotation speeds of the respective motors 10.
The number of revolutions of 0 is measured, and the master-slave relationship setting means 103
Is to set a master-slave relationship between the motors 100.

The mode switching means 104 switches at least the individual operation and the ratio operation of each motor 100, and the line speed setting means 105 sets the operation speed of the extrusion molding line.

The control means 106 has a rotation speed setting means 10 when operating independently.
The rotation speed signal from 1 is output to the speed command means, and the same speed command signal is output from the speed command means before and after mode switching during the ratio operation, and the rotation speed measuring means 1
02, the rotation speed ratio between the motors is calculated based on the measured rotation speed signal of each motor or the speed command signal from the speed command means 107 to each motor after the mode switching, and from the line speed setting means 105. Under the speed setting, a ratio rotation speed signal of the main and slave motors based on the rotation speed ratio is calculated and the rotation speed signal is output to the speed command means 107.

The speed command means 107 outputs a speed command signal for the main and slave motors 100 from the rotation speed signal from the control means 106 to the corresponding main and slave motors 100, and
The same latest speed command signal is output before and after the switching operation of the mode switching means 104.

The speed command means 107 may output the same speed command signal most recently, for example, the speed command means 107.
An example in which the device itself has a latch function for continuously outputting the latest speed command signal before and after the switching operation, and a storage means 10 for storing the latest rotation speed of each motor.
8 may be connected to the control means 106, and the control means 106 may output the latest rotation speed signal from the storage means 108 by the switching operation.

[Work]

In the present invention provided with such means, the mode switching means 1
When the mode is switched to the single operation mode by 04, the rotation speed signal from the rotation speed setting means 101 is output from the control means 106 to each motor 100 via the speed command means 107.

When switched to the ratio operation mode, the control means 106
Each motor 1 is based on the measured rotation speed signal from the rotation speed measurement means 102 or the speed command signal from the speed command means 107.
The rotation ratio between 00 and the line speed setting means 105 is calculated.
According to the speed setting from, the ratios of the rotation speeds of the main and slave motors are calculated and output to the speed command means 107, and the speed command means 107 outputs the speed command signals to the main and slave motors 100.

Before and after the mode switching operation by the mode switching means 104, the speed command means 107 itself outputs the latest speed command signal, or the control means 106 outputs the latest rotation speed signal from the storage means 108 to the speed command means 107. Then, the speed command means 107 outputs the most recent same speed command signal.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a schematic diagram showing an example of an extrusion molding line for implementing the motor control device according to the present invention.

In the figure, an extruder 1 includes a main screw 5 inside a molding machine table 3, an extrusion motor 7 for rotationally driving the main screw 5, and a rotation speed detection sensor 9 such as a tachogenerator for detecting the rotation speed of the extrusion motor 7. It has a conventionally known configuration having other configurations such as.

The molding machine table 3 is equipped with a raw material feeder device 15 having a hopper 11 for supplying a plastic raw material, an auxiliary screw 13 and the like, and the raw material feeder device 15 has a feeder motor 1 for rotationally driving the auxiliary screw 13.
7 and a sensor 19 for detecting the number of rotations of the feeder motor 17 are arranged.

Reference numerals 21 and 23 are a temperature sensor and a pressure sensor arranged on the molding machine base 3.

In this extruder 1, a plastic raw material supplied from a raw material feeder device 15 to a main screw 5 portion by a feeder motor 17 is driven by a rotation of the main screw 5 to form a molded product 25 from a die (not shown) arranged near the tip. Is to be extruded as.

The extruded molded product 25 has, for example, two sets of take-up machines 27, 2
It is designed to be picked up by 9 and each picking machine 2
Rollers 27a for picking up the molded product 25 at 7, 29,
29a is rotationally driven by the take-up motors 31 and 33, respectively, and the rotation speeds of the take-up motors 31 and 33 are detected by the sensors 35 and 37 similar to the sensors 9 and 19, respectively.

The extrusion motor 7, the feeder motor 17, the take-up motors 31, 33 and the sensors 9, 19, 35, 37 are connected to the motor control device A of the present invention by a cable or the like. 7, 17, 31,
It controls the number of rotations of 33.

FIG. 3 is a block diagram showing the configuration of a motor control device for an extrusion molding line according to the present invention.

In the figure, a control circuit 39 as control means outputs a rotation speed signal instructed to input, and a CPU 41 for calculating a ratio rotation speed in the ratio mode, and the CPU 41.
ROM 43 storing the operation program of CPU, and CPU 41
It is formed by having a RAM 45 for temporarily storing data in the calculation process of, a data input / output interface (I / O) 47, etc., and is a main part of a so-called microcomputer.

The master-slave relationship setting device 49, the mode switching device 51, the rotation speed setting device 53, and the line speed setting device 55 connected to the control circuit 39 are, as shown in FIG. 2, a keyboard 57 formed on the operation surface of the main body of the device. Is formed, and the details will be described later.

The master-slave relationship storage circuit 59, the rotation speed storage circuit 61, and the limit rotation speed storage circuit 63 connected to the control circuit 39 are
The external storage circuit 65 as a storage unit including a RAM is used by dividing the storage area.

The display device CRT connected to the control circuit 39 is a cathode ray tube display device that displays input / output data, and a plasma display device, for example, is used in addition to this.

The rotation speed measuring device 67 includes the rotation speed detecting sensors 9, 19, 35 and 37 shown in FIG.
3 which outputs an analog electric signal according to the number of revolutions, is connected to the control circuit 39 via an A / D conversion circuit 69 which converts the analog signal into a digital number of revolutions signal and outputs the measured number of revolutions signal. The rotational speed measuring means is formed by these.

The D / A conversion circuit 71 converts the digital rotation speed signal from the control circuit 39 into an analog signal and is connected to the speed command signal output circuit 73 to form speed command means. Reference numeral 73 is for outputting a speed command signal to the motors 7, 17, 31, 33 in FIG. 2 to control the rotation.

D / A conversion circuit 71 or speed command signal output circuit 73
Has a latch function or a memory function that keeps outputting the same speed command signal based on the rotation speed signal from the control circuit 39 unless the next rotation speed signal is output from the control circuit 39.

The mode switching device 51 is a mode setting means for setting whether or not the motor control device A controls each of the motors 7, 17, 31, 33 in the independent operation mode or the ratio operation mode,
The manual mode and the automatic mode can be selected under the single operation and the ratio operation mode, respectively, but it is sufficient that at least the single operation and the ratio operation mode can be set to be switched.

In the single operation mode, the manual mode is under the control of the control circuit 39 and individually controls each motor 7, 17, 31, 33 with the rotation speed input from the rotation speed setting device 53, and the automatic mode is controlled. Under the control of the circuit 39, each of the motors 7 is operated at the rotation speed previously input from the rotation speed setting device 53.
It is for automatically controlling 17, 31, and 33 individually.

Under the control of the control circuit 39, the ratio operation mode is based on the measured rotation speed signal input from the A / D conversion circuit 69 for the main motor and from the rotation speed of the main motor to which the slave motor depends on the slave motor. Calculate the ratio of each motor 7, 17,
The number of rotations of 31, 33 is controlled. In some cases, the ratio may be calculated from the signal related to the latest speed command signal from the D / A conversion circuit 71.

The master-slave relationship setting for each motor 7, 17, 31, 33 will be described later.

The rotation speed setting device 53 includes the motors 7, 17, 31, 33.
Is a rotation speed setting means for manually inputting the rotation speed of
Under the control of the control circuit 39, the rotation speed storage circuit 61 stores the data.

Further, from the rotation speed setting device 53, the maximum allowable rotation speed (limit rotation speed) of each motor 7, 17, 31, 33 can be input under the control of the control circuit 39.
Each limit rotation speed is stored in the limit rotation speed storage circuit 63.

The master-slave relationship setting device 49 includes the motors 7 and 1 in FIG.
It is a master-slave relationship setting means for setting and changing the master-slave relationship of which of 7, 31, 33 becomes the master motor and which becomes the slave motor for the master motor, and the master-slave relationship is controlled by the control circuit 39. It is adapted to be stored in the relational storage circuit 59.

Regarding the master-slave relationship, a configuration in which a plurality of motors are used as main motors and one or more slave motors are subordinate to each main motor,
A configuration in which another slave motor is slaved to a slave motor that is slaved to the main motor is optional.

FIG. 4 shows a rotation speed setting device 53 and a master-slave relationship setting device 4.
The limit rotation speed and the master-slave relationship of each motor 7, 17, 31, 33 set in 9 are shown on the display device CRT, and the numbers in the items indicating the master-slave relationship are the upper motors to which the slave motor depends. Is the number.

The line speed setting device 55 is a line speed command means for setting the molding operation speed of the whole or a part of the extrusion molding line shown in FIG.

The control circuit 39, when the rotation speed of each motor 7, 17, 31, 33 is input from the rotation speed setting device 53 under the condition that the mode switching device 51 selects the manual mode in the independent operation, does not change. D / A conversion circuit 7 for each rotation speed signal
1, and the rotation speed is stored in the rotation speed storage circuit 61.

When the mode switching device 51 selects the automatic mode in the independent operation, the number of revolutions input from the number of revolutions setting device 53 in advance, for example, the number of revolutions stored in the number-of-revolutions storage circuit 61 is read to read the respective motors 7, 17. , 31 and 33 are output to the D / A conversion circuit 71 in a predetermined procedure and stored in the rotation speed storage circuit 61.

The control circuit 39 refers to the master-slave relationship data stored in the master-slave relationship storage circuit 59 when the mode switching device 51 is selecting the ratio mode, and measures the rotation speed signal or D / D from the A / D conversion circuit 69. The rotation speed ratio of the master and slave motors is calculated from the signal related to the latest speed command signal from the A conversion circuit 71 (substantially a digital signal equivalent to the speed command signal), and the line speed setting device 55 outputs the signal to the main motor. Based on the speed setting, the rotation speed of each main motor is calculated, and the rotation speed of the sub motor is calculated from the rotation speed of the main motor according to the rotation speed ratio and output to the D / A conversion circuit 71. It has a function of storing the number of rotations.

The control circuit 39 receives the measured rotation speed signal of each of the motors 7, 17, 31, 33 or D / input from the A / D conversion circuit 69.
Each rotation speed signal output to the A conversion circuit 71 is compared with the limit rotation speed from the limit rotation speed storage circuit 63,
It is monitored whether or not even one unit exceeds the limit rotation speed, and if there is a motor that exceeds the limit rotation speed, the ratio rotation speed of the other main and slave motors at the time of exceeding is calculated to calculate the D / A conversion circuit. It outputs to 71 and has a function of suppressing the number of rotations of the motor that does not exceed the limit number of rotations.

Therefore, as shown in FIG. 5, certain motors 7, 17,
When the rotational speeds 31 and 33 reach the limit rotational speed (2), the rotational speeds of the other motors 7, 17, 31, 33 are controlled while maintaining a predetermined ratio even if they do not reach the rotational speed limit (1).

The motor control device having such a configuration operates independently by the mode switching device 51 unless a rotation speed signal different from the rotation speed signal once output from the control circuit 39 is output from the control circuit 39 to the D / A conversion circuit 71. Even when switching between the ratio operation mode and the ratio operation mode, a constant speed command signal is applied to the motors 7, 17, 31, 33 before and after the switching,
The number of rotations of the motors 7, 17, 31, 33 is difficult to change.

By the way, in the above-described embodiment, the D / A conversion circuit 71 or the speed command signal output circuit 73 has a latch function or a memory function to output a constant speed command signal before and after mode switching. The invention is not limited to this.

For example, when the mode is switched by the mode switching device 51,
The object of the present invention can be achieved even if the control circuit 39 is configured to read out the most recent rotation speed from the rotation speed storage circuit 61 and output it to the D / A conversion circuit 71.

Further, in the above-described configuration, the master-slave relationship of a plurality of motors in the extrusion molding line can be arbitrarily changed and set, and the rotation speed of the slave motor can be calculated as a ratio from the rotation speed of the main motor and output. Even if the line is variously changed, the optimum speed command system in various extrusion molding lines can be easily configured without changing the connection configuration of each motor.

〔The invention's effect〕

As described above, the motor control device of the present invention has a structure in which the speed command means outputs the same speed command signal before and after switching between the independent operation and the ratio operation mode for a plurality of motors arranged in the extrusion molding line. For example, the speed command means itself outputs the latest speed command signal by switching the mode switching means, or the control means outputs the latest rotation speed signal from the storage means to the speed command means by switching the mode switching means. Therefore, even if the operation mode is switched between the ratio operation mode and the single operation mode, no speed difference occurs between the motors at the time of switching.

Therefore, there is an advantage that a stable operation of the extrusion molding line can be ensured, and since it is not necessary to change the connection configuration of each motor, the configuration is simple and the workability is good.

[Brief description of drawings]

FIG. 1 is a claim correspondence diagram corresponding to the claims according to the present invention, FIG. 2 is a schematic diagram showing an example of an extrusion molding line including a motor control device of the present invention, and FIG. 3 is a motor according to the present invention. FIG. 4 is a block diagram showing an embodiment of a control device, FIG. 4 is a diagram showing an example of setting the master-slave relationship and limit rotation speed of each motor on the display device of FIG. 3, and FIG. 5 is a limit of each motor. It is a figure explaining the number of rotations. 1 ... Extruder 3 ... Molding machine base 5 ... Main screw 7 ... Extrusion motor 9, 19, 35, 37 ... Sensor 13 ... Sub screw 15 ... Raw material feeder device 17 ... Feeder motor 25 ...... Molded product 27,29 ...... Take-off machine 31, 33 ...... Take-off motor 39 ...... Control circuit 41 ...... CPU 49 ...... Master-slave relationship setting device 51 ...... Mode switching device 53 ...... Rotational speed setting device 55 ... Line speed setting device 59 ... Master / slave relationship memory circuit 61 ... Ratio rotation speed memory circuit 63 ... Limit rotation speed memory circuit 67 ... Rotation speed measuring device 69 ... A / D conversion circuit 71 ... D / A conversion Circuit 73 ... Speed command signal output circuit A ... Motor control device CRT ... Display device 100 ... Motor 101 ... Rotation speed setting means 102 ... Rotation speed measuring means 103 ... Master-slave relationship setting means 04 ...... mode switching means 105 ...... line speed setting means 106 ...... control means 107 ...... speed command means 108 ...... storage means

Claims (3)

[Claims] 1. A plurality of motors arranged in an extrusion molding line including an extrusion molding machine, rotation speed setting means for setting the rotation speeds of the plurality of motors, and rotation speed measurement for measuring the rotation speeds of the respective motors. Means, a master-slave relationship setting means for setting a mutual master-slave relationship between the respective motors, a mode switching means for switching at least the individual operation and the ratio operation of the respective motors, and a line speed for setting the operating speed of the extrusion molding line. The setting means and the speed command signals of the main and slave motors are output from the input rotation speed signal to the corresponding main and slave motors, and the same speed command signals immediately before and after the switching operation of the mode switching means are output. The speed command means for outputting and the rotation speed from the rotation speed setting means are output to the speed command means during the independent operation, and the mode is switched during the ratio operation. The same speed command signal before and after is output from the speed command means, and the measured rotation speed signal of each motor from the rotation speed measurement means or the speed command to each motor after the mode switching from the speed command means The rotation speed ratio between the motors is calculated based on the signal, and the rotation speed signals of the main and slave motors are calculated based on the rotation speed ratio by the speed setting from the line speed setting means to calculate the speed command means. A motor control device for an extrusion molding line, comprising: a control unit that outputs the rotation speed signal to the control unit, and suppresses a speed difference of the motor when switching between the single operation and the ratio operation. 2. The motor control device for an extrusion molding line according to claim 1, wherein the speed command means itself continues to output the latest speed command signal before and after the switching operation of the mode switching means. 3. A storage means for storing the latest rotation speed of each of the motors is connected to the control means, and the control means causes the control means to perform the latest rotation speed from the storage means. The motor control device for an extrusion molding line according to claim 1, which outputs a signal.