JPS63271829A - Manufacturing device for foam-coated electric wire - Google Patents

Abstract

PURPOSE:To keep the outer diameter of a foam coating tube constant by increasing or decreasing the winding speed based on the low-frequency component of the outer diameter fluctuation of a core wire and the outer diameter fluctuation of the foam coating tube. CONSTITUTION:The outer diameter of a core wire 100 delivered from a reel 1 is detected with a measuring instrument 6, and the low-frequency component is extracted in a circuit 22. The running time is delayed in response to the passage length of arranged positions of outer diameter measuring instruments 6, 11 in a delay circuit 23 and fed to a comparing circuit 26. A foam core wire 101 formed when passing a furnace 7 is cooled with the liquid 8a in a tank 8, its outer diameter is detected with the measuring instrument 11 when passing the second outer diameter measuring instrument, and the low-frequency component is extracted in a circuit 25. Outputs of the circuits 23, 25 are compared in the circuit 26, the difference output is fed via an integrator and mixed with the output of a reference signal setting circuit 29 in a circuit 28, and it is fed to a winding motor 31 via a driving circuit 30. The winding speed is decreased. When the outer diameter of the core wire 100 becomes thin and increased when thick to keep the outer diameter constant.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a manufacturing device for a foam-covered electric wire, and more particularly to a manufacturing device that can obtain a foam-covered electric wire whose finished outer diameter is controlled to be constant. It is.

[Prior Art] Foam-covered electric wires are made, for example, by adding a foaming agent to polyethylene and foaming it, or by pressurizing gas into molten polyethylene to mix inert gas in the form of closed cells.

At this time, the degree of foaming can be changed by adjusting the gas pressure, so the desired low dielectric constant can be obtained to some extent, and the dielectric loss tangent is also small, so it is widely used as shield wires and coaxial cables in communication cables, etc. ing.

A pre-foamed wire (hereinafter referred to as "core wire") formed on the outer periphery of a core conductor using an extruder is continuously passed through a heating furnace to foam and form a desired foam coating. It is being done. The foamed covered wire is then wound up by a winding machine.

[Problems to be Solved by the Invention] When the core wire of a foam-covered electric wire is continuously manufactured, the outer diameter tolerance is about ±7 μm, which is a value obtained by a general extruder. Furthermore, when extrusion is carried out continuously over a long period of time, this value usually has a characteristic that the high frequency component fluctuates slightly while the low frequency component fluctuates greatly.

Such fluctuations cause fluctuations in the foaming state in the heating furnace, and greatly influence the accuracy of the outer diameter of the foam-covered electric wire finally obtained.

In other words, the outer diameter of the core wire changes from +P to -P, which corresponds to a general outer diameter tolerance of about ±7 μm, as shown in Figure 3.
Generally, the high frequency components fluctuate slightly while the low frequency components fluctuate greatly. When manufacturing and covering a foam-covered electric wire using such a core wire, the outer diameter of the foam coating layer that is finally obtained varies within ±5 μm, which is the general outer diameter tolerance, as shown in Figure 4. Corresponding +Q
It is common for low frequency components to have large fluctuations while high frequency components have small fluctuations between -Q and -Q.

Further, as the outer diameter of the core wire becomes thicker, the outer diameter of the foam-covered electric wire becomes thinner, and conversely, as the outer diameter of the core wire becomes thinner, the outer diameter of the foam-covered electric wire becomes thicker. This seems to be due to the difference in heat capacity of the core wire with respect to its outer diameter.

Moreover, minute fluctuations in a short time, in other words, fluctuations in high frequency components, do not pose a problem because there is mutual interference in the longitudinal direction of the foam-covered electric wire due to the foaming mechanism.

Accordingly, an object of the present invention is to provide an I-making apparatus that can obtain a foam-covered electric wire in which the outer diameter of the foam coating layer of the final foam-covered electric wire is made constant.

[Means for Solving the Problems] The foam-coated electric wire manufacturing apparatus according to the present invention runs a core wire, which has a coating containing a thermally decomposable foaming agent formed on the outer periphery of a core conductor, through a heating furnace. In an apparatus for manufacturing a foam-covered electric wire that is wound with a winder after obtaining a foam coating layer by forming a foam coating layer, a first outer diameter measuring device detects the outer diameter of the core wire, and a first outer diameter measuring device detects the outer diameter of the foam coating layer after foaming. a second outer diameter measuring device for detecting; a first extraction circuit for extracting the low frequency component of the output of the first outer diameter measuring device; and a first extraction circuit for extracting the low frequency component of the output of the second outer diameter measuring device; a second extraction circuit for extracting, and the first
and a control circuit that controls the winding speed in the winder based on the correlation between the respective outputs of the second extraction circuit.

[Function] In the manufacturing process of the foam-coated electric wire according to the present invention, the winding speed of the winding machine is increased or decreased based on the outer diameter variation of the core wire and the low frequency component of the outer diameter variation of the foam coating layer. This keeps the outer diameter of the foamed coating layer constant.

[Example] Hereinafter, an example of the present invention will be described in which a core wire 100 formed on the outer periphery of a core wire conductor as shown in FIGS. 1 and 2 is wound around a supply reel 1 and pulled out from the supply reel 1. core wire 10
0 passes through a loop 2 for stabilizing the cable running and for making exchange connections while the wire is running, and further passes through a first outer diameter measuring device 6 via a guide roller 3.4.5, It is designed to be guided to a heating furnace 7.

This first outer diameter measuring device 6 is for removing the core wire 100. The foamed core wire 101 that has passed through such a heating furnace 7 is cooled through a guide roller 9 disposed in a cooling water tank 8 filled with a cooling liquid 8a, and then cooled through a guide roller 10. 2 outer diameter measuring device 11
After passing through the rollers 13 and 14 forming the take-up machine 2 in a loop shape, it is wound onto the take-up reel 16 of the take-up machine 15.

This second outer diameter measuring device 11 is for detecting the outer diameter of the foamed coating diagram after foaming, that is, the outer diameter of the foamed core wire 101.
The take-up reel 16 is rotated by the rotational driving force of the take-up motor 31.

The foam-coated electric wire manufacturing apparatus configured in this way has a second
The circuit sections shown in the figure are connected.

That is, the output end of the first outer diameter measuring device 6 is connected to a first extraction circuit 22 formed of an El-pass filter that extracts the low frequency component of the output, and a delay circuit 23 having a delay time τ.
The output end of the second outer diameter measuring device 11 is connected to one input end of the comparator circuit 26 via
is connected to the other input terminal of the comparison circuit 26 via the extraction circuit 25 in sequence.

The output terminal of this comparison circuit 26 is connected to one input terminal of a mixing circuit 28 via an integrator 27.
The output terminal of the reference signal setting circuit 29 is connected to the other input terminal of the reference signal setting circuit 29 .

Further, the delay time τ in the delay circuit 23 is set to a travel time corresponding to the route length between the installation position of the first outside diameter measuring device 6 and the installation position of the second outside diameter measuring device 11. .

The output end of the mixing circuit 28 is connected to a winding motor 31 via a drive circuit 30.

Such a comparison circuit 26. Integrator 27. Mixing circuit 28.
Reference signal @ setting circuit 29. The drive circuit 30 forms a control circuit that controls the winding speed of the winding reel 16 in the winding machine 15 based on the correlation between the respective outputs of the first and second extraction circuits 22,25. be.

Therefore, when the core wire 100 unwound from the supply reel 1 passes through the loop 2 and the guide roller 3.4.5 in sequence and passes through the first outer diameter measuring device 6, it is measured by the first outer diameter measuring device 6. The outer diameter of the core wire 100 is detected, and its output is passed through the first extraction circuit 22 to extract the low frequency component. This low-frequency component signal is delayed by a travel time corresponding to the route length of the installation positions of the first and second outer diameter measuring devices 6 and 11 by the delay circuit 23, and then inputted to the comparison circuit 26. be done.

On the other hand, a foamed core wire 101 formed by passing through a heating furnace 7
The outer diameter of the foam core wire 101 is detected by the second outer diameter measuring device 11 when it is cooled by the cooling liquid 8a in the cooling water tank 8 and passing through the second outer diameter measuring device 11, and its output is the second outer diameter measuring device 11. The low frequency components are extracted by passing through the second extraction circuit 25.

This low frequency component signal is input to the comparator circuit 26. This comparison circuit 26 compares the power of both the delay circuit 23 and the second extraction circuit 25, and the difference output is sent to the integrator 2.
7, the output of the integrator 27 is supplied to a mixing circuit 28,
The signal is mixed with the output of the reference signal setting circuit 29. The output of the mixing circuit 28 is then supplied to the winding motor 31 via the drive circuit 30.

Here, the output setting of the reference signal setting circuit 29 is determined by the delay circuit 23. When the Ryokawa forces of the second extraction circuit 25 match, in other words, when the differential output of the comparator circuit 26 is zero, the value is appropriate for applying a predetermined rotational force to the winding motor 31.

Therefore, when the outer diameter of the core wire 100 becomes thicker, the output of the first outer diameter measuring device 6 increases, and accordingly, the output of the delay circuit 23 increases. At the same time, the output of the second outer diameter measuring device 11 decreases, and as a result, the output of the comparison circuit 26 increases. Then, the integrator 27. Mixing circuit 28. Drive circuit 3
The rotation of the winding motor 31, which is rotationally driven through 0, is reduced. For this reason, the winding speed of the foamed core wire 101 is reduced, and the outer diameter of the foamed core wire 101 is controlled to increase.

Conversely, when the outer diameter of the core wire 100 becomes thinner, the output of the first outer diameter measuring device 6 decreases, and the output of the delay circuit 23 decreases accordingly. At the same time, the output of the second outer diameter measuring device 11 increases, and as a result, the output of the comparison circuit 26 decreases. Then, the integrator 27, the mixing circuit 28 . Drive circuit 3
The rotation of the winding motor 31, which is rotationally driven through 0, is increased.

For this reason, the winding speed of the foamed core wire 101 is increased, and the outer diameter of the foamed core wire 101 is controlled to decrease.

For this reason, the outer diameter of the foamed core wire 101 is controlled to be constant in response to variations in the outer diameter of the core wire 100.

In addition, since the first extraction circuit 22 and the second extraction circuit 25 are provided for small fluctuations in a short time, in other words, fluctuations in high frequency components, they are irrelevant to the outer diameter control. Therefore, control is not performed with an unnecessarily fast response time, and the control operation is never unstable.

As a condition for foaming, there is a close relationship between the outer diameter and the degree of foaming, that is, capacitance; the larger the outer diameter, the smaller the capacitance, and conversely, the smaller the outer diameter, the larger the capacitance. (in the same foaming state). Therefore, the variation in the outer diameter also affects the capacitance, and under the same foaming state, the capacitance can be made constant by eliminating the variation in the outer diameter.

[Effects of the Invention] As described above, according to the foam-coated electric wire production 1 according to the present invention, the speed of the winding reel of the winding machine is controlled based on the low frequency component of the variation in the outer diameter of the core wire. Therefore, there is an apparatus for manufacturing a foam-covered wire that can perform extremely stable outer diameter i+l control and can obtain a foam-covered wire with a constant outer diameter of the foam coating layer of the foam-covered wire obtained by R reduction. I can provide it.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of a foam-covered electric wire manufacturing apparatus showing an embodiment of the present invention, and FIG. 2 is a circuit diagram showing an electric circuit connected to the foam-covered electric wire manufacturing apparatus shown in FIG. 1. , FIG. 3 is a diagram showing an example of variation in the outer diameter of the core wire, and FIG. 4 is a diagram showing an example of variation in the outer diameter of the foamed core wire. 100... Core wire '101... Foamed core wire 6... I...
...First outer diameter measuring device 7...Heating furnace 8...Cooling water tank 11...Second outer diameter measurement Vessel 15...
... Winder 16 ... Winding reel 22 ... First extraction circuit 25 ...
...Second extraction circuit 23...Delay circuit 26...Comparison circuit 27...Integrator 28... ...Mixing circuit 29...Reference signal setting circuit 30...
... Drive circuit 31 ... Winding motor patent applicant Hitachi Cable Co., Ltd. Agent Koyama 1) Former husband Fig. 1 Fig. 2

Claims (1)

[Claims] A foaming method in which a core wire in which a coating containing a thermally decomposable foaming agent is formed on the outer periphery of a core conductor is passed through a heating furnace while running to obtain a foam coating layer, and then wound up with a winder. In a covered wire manufacturing device, the first step detects the outer diameter of the core wire.
a second outer diameter measuring device that detects the outer diameter of the foamed coating layer after foaming; and a first extraction circuit that extracts a low frequency component of the output of the first outer diameter measuring device. and a second extraction circuit that extracts the low frequency component of the output of the second outer diameter measuring device, and winding in the winder based on the correlation between the outputs of the first and second extraction circuits. 1. A foam-covered electric wire manufacturing device, comprising: a control circuit for controlling a removal speed;