JPS6266510A - Control of extrusion covered line - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a method of controlling an extrusion coating line used for manufacturing electric wires and cables, and particularly to a technique for stabilizing line speed and take-off tension.

[Prior art and its problems]

When manufacturing electric wires by extruding conductive wires with rubber or plastic sheaths, or manufacturing cables by extruding rubber or plastic sheaths around cable cores, the thickness of the sheathing material (rubber or plastic) must be determined. In order to make the material uniform in the longitudinal direction, it is necessary to keep the extrusion rate of the extruder constant and the speed of the core material (wire rod, cable core, etc.) passing through the extruder constant.

The amount of extrusion from an extruder is determined by the rotational speed of the screw, so it is relatively easy to keep it constant; however, it is difficult to keep the speed of the core material that passes through the extruder constant for the following reasons. It was difficult to do so.

In other words, in the conventional extrusion coating line, the core material fed out from the drum (or bobbin) is passed through an extruder, the outer periphery of the core material is extruded and coated with the coating material, and the coating material that comes out of the extruder is passed through a cooling water tank. The structure is such that the material is taken up by a take-up machine at a constant speed and then wound onto the wind-up machine.

In such an extrusion coating line, the speed of the core material passing through the extruder depends on the take-up speed of the take-off machine, but there is a cooling water tank between the extruder and take-off machine, and the distance between them is Because it is long, if the take-up tension changes for some reason, the elongation and slack of the core material will change, and the speed of the core material passing through the extruder will change. In order to stabilize the pulling tension, there is a method of applying a brake to the drum that unwinds the core material and adding back tension to the core material, but even with this method, the tension of the core material fluctuates depending on the amount and condition of the core material being wound. There's a problem.

c. Means for solving the problem and its operation] The present invention provides a control method for an extrusion coating line that solves the problems of the prior art as described above. between the drum and the extruder)
A sending machine that sends out the core material in a non-slip manner is installed, and a take-up machine that takes up the covering body in a non-slip manner after the extruder is installed, and the extruder, the send-out machine, and the take-up machine are each driven by DC separately excited electric motors, The sending machine controls its line speed to maintain a constant relationship with the screw rotation speed of the extruder, and the take-up machine gives a speed command corresponding to a line speed higher than the line speed of the sending machine. , is characterized in that it is driven in a state where a current limit command is given to set the upper limit of armature current according to the required take-up tension.

In this control method, the speed of the core material passing through the extruder is determined by a feeder whose speed is controlled so as to maintain a constant relationship with the screw rotational speed of the extruder. Since the pulling machine is given a speed command corresponding to a line speed higher than the line speed of the sheathing, it tries to increase the speed, but since the armature current is limited by the current limit command, it will exceed a certain limit. As a result, the torque does not increase, and the covering is pulled at a constant tension by the feeding machine at a fixed running speed.

〔Example〕

FIG. 1 shows an embodiment of the invention. In the figure, 11 is a feeder, 12 is an extruder, 13 is a cooling water tank, and 14 is a take-up machine. In the feeding step 4111, the core material 15 fed out from a drum (not shown) is held between rotating endless healds so as not to slip, and sent to the extruder 12. Further, the take-up machine 14 takes the covering body 16 that has exited the extrusion 1112 and has been cooled in the cooling water tank 13 by pinching it with a rotating endless belt so as not to slip, and sends it to a winding machine (not shown).

Further, 17 is a separately excited DC motor that drives the feeder 11, 18 is a separately excited DC motor that drives the screw of the extruder 9112, and 19 is a separately excited DC motor that drives the take-up machine 14. The excitation of each electric motor 17, 1B, and 19 is constant. 20, 21, and 22 are electric motors 17 and 1, respectively.
8 and 19 are drive control units, and 23, 24, and 25 are electric motors 17, 18, and 1, respectively.
The drive control unit detects the rotational speed of 9) 20, 21,
This is a speed generator that feeds back to 22.

Furthermore, 26 is an extrusion amount setting device, 27 is a switch for starting and stopping the line, 28 is a ramp setting device (single integrator) for setting the rise and fall times of the line, and 29 is an extruder 1
2 is an operational amplifier that correlates the screw rotation speed (extrusion amount) with the line speed of the feeder 11; 30 is an operational amplifier that correlates the line speed of the feeder 11 and the take-up machine 14; 31 is an operational amplifier that correlates the line speed of the take-up machine 14 with This is a speed difference setting device for setting higher than that of No. 11.

Further, 32 is a current setting device for setting the upper limit of the armature current of the motor 19 on the receiving machine side, 33 is a current controller, and 34 is a differentiator for compensating the acceleration torque at the time of line rise.

The drive control units 20 and 21 of the electric motors 17 and 18 are ordinary ones, but the drive control unit 22 of the electric motor 19 has a configuration as shown in FIG. 2 in order to limit the current of the inlet. That is, 35 is a speed control unit that operates by inputting the speed command from the operational amplifier 34 and the speed signal from the speed generator 25, and 36 is the speed signal from the speed control unit 35 and the armature current from the current controller 33. This is an operational amplifier that operates by inputting a limit signal.
This is to limit the output torque of the motor. 37 is a thyristor single firing angle control circuit, 38 is a thyristor circuit,
39 is a current detector. As described above, the current limit signal and the speed command signal are calculated by the operational amplifier 36, and this signal drives the firing angle control circuit 37 to operate the thyristor and drive the electric motor 19.

Next, the control method will be explained.

The speed command X to the extruder 12 corresponds to the extrusion amount set by the extrusion amount setting device 26, and the electric motor 1B rotates at a speed corresponding to this speed command X, and the screw rotates.
Extruder 12 extrudes a set amount of dressing.

In addition, on the feeding machine ll side, the operational amplifier 29 calculates the speed command yl of the feeding machine 11 based on the speed command X, and the electric motor 17 rotates at a speed according to the speed command yl. The core material 15 is fed out at a speed that is in a constant relationship (eg, proportional relationship) to the screw rotation speed of the extruder 12.

Furthermore, on the collecting machine 14 side, an operational amplifier 29 calculates a speed command y2 for the collecting machine 14 based on the speed command y1. At this time, in order to always make the speed command y8 of the take-up machine 14 higher than the speed command y of the feeder 11 by a constant width, a speed difference C set by the speed difference setting device 31 is added. In other words, the relationship between the speed command yI and Vt is as shown in FIG. As a result, the electric motor 19 receives the calculated speed command y2.
It tries to rotate at a speed according to the 4111
4 clamps the covering 16 to prevent it from slibbing, so the line speed will not rise above the speed set by the feeder 11. However, if this continues, the electric motor 19
The armature current of the motor 19 increases, the torque increases, and the take-up tension becomes excessive. Therefore, the upper limit of the armature current of the electric motor 8119 is set by the current setting device 32, and the torque of the electric motor 19 is prevented from rising above a certain limit. I try not to.

As a result, the take-up machine 14 attempts to reach a speed corresponding to the speed command y, but since the take-up torque is limited, the speed does not increase, and the line speed eventually decreases to the feeder 11.
It will be restricted to the speed set by . In particular, since the feeder 11 can be placed close to the extruder 12, the speed of the core material 15 passing through the extruder 12 is not affected by elongation or slack of the core material 15, and is almost equal to the speed set by the feeder 11. Become that. Moreover, the take-off tension is stabilized at the maximum take-off tension of the take-off machine 14 determined by the current limit.

Therefore, the relationship between the speed of the core material passing through the extruder and the extrusion rate of the extruder is stable, and a coated body with little variation in coating thickness in the longitudinal direction can be produced.

Note that if the current of the electric motor 19 is limited, the acceleration torque required at the time of line rise may be insufficient. The necessary acceleration torque can be obtained by

〔Effect of the invention〕

As explained above, according to the present invention, a feeder is installed before the extruder, and a take-off machine is installed after the extruder, and the line speed is set by the feeder and the take-off tension is set by the take-off machine. This has the advantage that the speed of the core material passing through the extruder is stable, and extrusion coating can be performed with a uniform coating thickness in the longitudinal direction.

[Brief explanation of drawings]

Fig. 1 is a control system diagram showing the control method for an extrusion coating line according to the present invention, Fig. 2 is a detailed view of the drive control unit on the take-up machine side in Fig. 1, and Fig. 3 is a diagram showing the speed command on the delivery machine side. It is a graph showing the relationship between speed commands on the collecting machine side. 11-feeding machine, 12-extruder, 13-cooling water tank, 1
4 ~ Taking machine, 15 ~ Heartwood, 16 ~ Covering body, 17.1
8.19~DC separately excited motor, 20.2I.22~Drive control unit, 26~Extrusion amount setter, 29.30~Operation amplifier, 31~Feed rate difference setter, 32~Current setter, 33
~Current controller.

Claims (1)

[Claims] A feeder is installed in front of the extruder to send out the core material in a non-slip manner, and a take-off machine is installed after the extruder to take over the coating in a non-slip manner. The feeder is controlled so that its line speed maintains a constant relationship with the screw rotation speed of the extruder, and the take-off machine has a line speed that is higher than the line speed of the feeder. A method for controlling an extrusion coating line, characterized in that the extrusion coating line is driven in a state where a speed command is given and a current limit command is given to set an upper limit of armature current according to a required take-up tension.