JPS6112604B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling the capacitance of wire in the manufacture of foamed plastic insulated wire.
In communication cables, unbalanced capacitance between lines causes crosstalk, and for this reason, the capacitance formed between conductors across the insulation coating layer of each insulated wire that makes up a communication cable must be reduced. It needs to be evenly aligned over the entire length.

This type of capacitance C is calculated per unit length of the insulated wire, C=K・ε/logD/d( K: Dielectric constant of vacuum)...
(1) The capacitance C can be controlled by adjusting any of the conductor diameter, coating outer diameter, and dielectric constant.

Therefore, in recent years, as a method of controlling the capacitance of foamed plastic insulated wires to maintain a constant value, a cooling tank movable in the running direction of the wire is provided on the exit side of the extruder in the extrusion coating process. By adjusting the foaming rate of the foamed plastic by moving the position of, its dielectric constant can be adjusted;
Methods have been adopted to control the capacitance of wires.

FIG. 1 is a diagram illustrating an example of a method for controlling the capacitance of an electric wire in the manufacturing process of a foamed plastic insulated electric wire, and the conventional control method will be explained using this diagram. In the figure, after a foamed plastic insulator is extruded from an extruder 3 onto a conductor 2 supplied from a supply device 1, it is cooled in a cooling water tank 5, and wound while being drawn at a constant speed by a capstan 7. Foamed plastic insulated wire 9 on the handle 8
is wound up. The capacitance of the electric wire 9 is usually measured as a capacitance deviation from a reference value by a capacitance measuring device 10 connected to a capacitance detection electrode 6 provided at an arbitrary position in the cooling water tank 5. Ru.

Further, a movable water tank 4 is provided inscribed on the inlet side of the cooling water tank 5 and is movable back and forth in the running direction of the electric wire, so that the distance l from the extrusion die to the movable water tank 4 can be changed. , by changing this distance l, the capacitance of the extruded wire changes.

Conventionally, in order to control the capacitance C of the extruded foamed plastic electric wire 9, the deviation △ from a reference value of capacitance measured by a capacitance measuring device 10 is used.
The method used was to multiply Cs by a coefficient f ₁ (for example, a distance of 15 mm per 1 picofuate deviation) to obtain the moving distance △l ₁ of the movable water tank 4, and to move by that amount. In this case, the coefficient f ₁ takes a constant value regardless of the linear speed of the electric wire, so depending on the linear speed, there is a large error between the actual required moving distance and the moving water tank 4 is changed to △l ₁ Even after movement, there is a deviation from the reference value of capacitance, and this is repeated, resulting in a slow response until the capacitance converges to the reference value.

Note that the determination of the distance Δl ₁ from the above-mentioned capacitance deviation ΔCs and the operation related to the movement of the movable water tank 4 are performed by the control device 11 shown in FIG.

The present invention solves the above-mentioned drawbacks, and is a method that eliminates the conventional error in the moving distance of a moving water tank due to changes in linear speed, has a fast response speed, and can control the capacitance of a foamed plastic insulated wire with high precision. We aim to provide the following.

The present invention provides a method for controlling the capacitance of an extrusion-coated foamed plastic insulated wire by adjusting the moving distance of a moving water tank for cooling the wire after extrusion, based on the measured value of a capacitance measuring device. , a method for manufacturing a foamed plastic insulated wire, characterized in that the moving distance of the moving water tank is adjusted in proportion to the product of the capacitance deviation measured by the capacitance measuring device and the linear speed of the wire. .

Hereinafter, the present invention will be explained by examples using the drawings. In the present invention, the method of manufacturing the foamed plastic insulated wire is the same as the conventional method already described with reference to FIG.

The present inventor has discovered that there is the following relationship between the capacitance of the electric wire described above and the cooling conditions of the extrusion-coated electric wire.

Figure 2 is a diagram showing the relationship between the above-mentioned capacitance C and the distance l from the extrusion die to the moving water tank 4. As shown in the figure, the relationship between the two is a curve that varies depending on the linear velocity V (m/min) of the electric wire. , which shows that there is a nearly linear relationship until the capacitance C reaches near the minimum value.

In this figure, the horizontal axis is the time t from when the foamed plastic exits the extrusion die until it enters the moving water tank 4.
, the relationship between capacitance C and time t is the third
As shown in the figure, the curves are almost the same for each linear velocity. That is, it can be seen that the capacitance C depends on the time t regardless of the linear velocity, and has a substantially linear relationship.

Therefore, in order to control the capacitance C shown in FIG. 3, it is sufficient to adjust the time t.

That is, the movable water tank may be moved in a direction in which the time t from the extrusion die to the movement water tank is shifted by Δt in proportion to the deviation ΔCs of the capacitance from the reference value. On the other hand, from Figure 3, there is a relationship △Cs∝△t, and t = l/V, so if the corrected movement distance is △l, then △Cs∝△l/V Therefore, if f ₂ is the coefficient, then , △l≒f ₂ △Cs・V ...(2) The present invention utilizes the relationship shown in equation (2), and the capacitance measured by the capacitance measuring device 10 shown in FIG. The moving distance △l of the moving water tank 4 is calculated by multiplying the product of the deviation △Cs and the linear velocity V of the electric wire, which is measured separately or set, by a certain coefficient _f2 . Calculation of Δl from , and operations related to movement of the movable water tank 4 are performed by the control device 11.

In this case, the coefficient f ₂ is constant regardless of the linear velocity as described above, and if it is determined in advance by actual measurement,
There is no need to change it depending on the linear speed, the moving distance △l can be calculated, and the moving distance with a small error required to correct the capacitance deviation is determined, so the capacitance after moving the moving aquarium is the standard. Therefore, the capacitance of the electric wire can be easily controlled with high response speed and accuracy.

As described above, the present invention provides a method for controlling the capacitance of an extrusion-coated foamed plastic insulated wire by multiplying the capacitance deviation ΔCs measured by a capacitance measuring device and the linear velocity V of the wire. In other words, by multiplying the product by a certain coefficient _f2 , the moving distance of the cooling water tank △
Since the movement is performed in search of l, there is no need to change the coefficient f ₂ depending on the linear velocity, and the movement distance with less error required to correct the capacitance deviation can be found, and the capacitance after correction is close to the reference value. Therefore, it is possible to easily control the capacitance of the foamed plastic insulated wire with high response speed and accuracy.

[Brief explanation of the drawing]

FIG. 1 is a diagram illustrating an example of a method for controlling the capacitance of an electric wire in the manufacturing process of a foamed plastic insulated electric wire. Figure 2 shows the relationship between the capacitance of foamed plastic and the distance from the extrusion die to the moving water tank, and Figure 3 shows the relationship between the capacitance and the time from exiting the extrusion die to entering the moving water tank. FIG. DESCRIPTION OF SYMBOLS 1... Supply device, 2... Conductor, 3... Extruder, 4... Moving water tank, 5... Cooling water tank, 6... Capacitance detection electrode, 7... Capstan, 8... Winding machine, 9...Foamed plastic insulated wire, 10...
...Capacitance measuring device, 11...Control device.

Claims (1)

[Claims] 1. In a method of controlling the capacitance by adjusting the moving distance of a moving water tank for cooling the wire after extrusion, based on the measured value of the capacitance measuring device of the extrusion-coated foamed plastic insulated wire, A method for manufacturing a foamed plastic insulated wire, characterized in that the moving distance of the moving water tank is adjusted in proportion to the product of the capacitance deviation measured by a capacitance measuring device and the linear speed of the wire.