JPH0618091B2 - Method for manufacturing foam insulated wire - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a foam insulated wire.

[Prior Art] In the manufacturing process of thermoplastic synthetic resin foam insulated wire, the outer diameter of the wire (core outer diameter) and capacitance, the outer diameter of the metal filament (conductor outer diameter), etc. are important management items. is there.

Among these, there is a correlation between the outer diameter of the core and the capacitance.Therefore, controlling each individually causes problems such as hunting of each value, and it takes time to obtain stable extrusion conditions. It was

As a method of controlling the outer diameter of the core, a method of controlling the extrusion rotation speed or the take-up speed by a signal from the outer diameter measuring device is known.

Also, as a method of controlling the capacitance of the electric wire, when the outer diameter of the conductor is fixed, the extrusion temperature, the cooling rate after coating, the cooling temperature, the injection amount of the foaming agent, etc. are signaled from the capacitance measuring device. It is known to control by.

However, in the method of controlling the electrostatic capacity, the outer diameter of the core is affected because the foaming degree of the resin is changed.

Therefore, it is not easy to automatically control the outer diameter of the core and the electrostatic capacity at the same time, and it takes a long time to stabilize the core, because hunting is required a plurality of times.

[Problems to be Solved by the Invention] In the above-mentioned conventional technology, it is not easy to automatically control the core outer diameter and the capacitance at the same time, and it takes a long time to obtain stable extrusion conditions due to multiple hunting. Was needed.

The present invention has been made in view of the above points, and it is possible to easily obtain stable extrusion conditions by minimizing the fluctuation of the core outer diameter and the core capacitance when extruding the foam insulated wire. It is an object of the present invention to provide a method for producing the foam insulated wire.

[Means for Solving the Problems] The purpose is to measure the outer diameter of the conductor after preheating, the outer diameter of the electric wire before and after the wire is taken up by a take-up machine, and the capacitance, and to obtain these measured values and the conductors. Enter the outer diameter, the outer diameter of the wire covered with the foamed resin, the capacitance and the set value of the dielectric constant of the resin into the calculator, and the calculator calculates the degree of foaming of the foamed resin and the basis weight of the foamed resin. The value of the basis weight of the foamed resin calculated by is the target value calculated by the set value.The extrusion rotation speed and the take-up speed are controlled by the basis weight control output to control the core outer diameter. The extrusion temperature, the cooling speed of the wire after coating, the cooling temperature, and the injection amount of the foaming agent are controlled by the foaming degree control output so that the calculated foaming degree of the foamed resin becomes the target value calculated by the set value. Controlling capacitance, so to speak, the core outer diameter and capacitance This is achieved by controlling separately rather than simultaneously.

[Operation] As described above, the measured values of the outer diameter of the conductor, the outer diameter of the core, and the core capacitance, and the set values of the outer diameter of the conductor, the outer diameter of the core, the core capacitance, and the dielectric constant of the resin are set. Processing with a calculator, calculating the foaming degree of the foamed resin and the basis weight of the foamed resin, and the basis weight control output so that the value of the basis weight of the foamed resin calculated by the measured value becomes the target value calculated by the set value. The extrusion rotation speed and the take-up speed are controlled to control the core outer diameter, and the extrusion degree is controlled by the foaming degree control output so that the foaming degree of the foamed resin calculated by the measured value becomes the target value calculated by the set value. Since the temperature, the cooling rate of the electric wire after coating, the cooling temperature, and the injection amount of the foaming agent are controlled to control the capacitance,
Control is easy because there is no correlation between the outer diameter of the core and the capacitance.

Further, since there are few control items for the control output, there is an advantage that the response is quick.

Therefore, when the coated electric wire is extruded, variations in the core outer diameter and the core capacitance can be minimized, and stable extrusion conditions can be easily obtained.

Incidentally, if a is the conductor outer diameter, b is the core outer diameter, c is the core capacitance, and ε is the dielectric constant of the foamed resin between the capacitance of the core, the outer diameter of the core, and the outer diameter of the conductor, It is said that a relational expression such as the expression (1) holds.

By the way, ε is determined by the dielectric constant of the resin and the foaming degree of the foamed resin. If P is the foaming degree of the foamed resin and ε ₀ is the dielectric constant of the resin, a Bethel equation such as equation (2) can be obtained. To establish.

Therefore, if a resin having a known dielectric constant is used to obtain a fixed core outer diameter, capacitance, and conductor outer diameter, the degree of foaming of the foamed resin can be calculated by itself.

Since the proportion of resin in the foamed resin can be known from this,
The weight per unit length of wire is also determined.

[Examples] Hereinafter, the present invention will be described based on illustrated examples.

FIG. 1 shows an embodiment of the present invention.

As shown in the figure, the method of manufacturing the foam insulated wire is
The delivery device 1, the preheating device 2, the extruder 3, the cooling water tank 4 (moving cooling water tank 4a, fixed cooling water tank 4b), the take-up machine 5, the accumulator 6, and the winder 7 are provided, and the conductor 8 sent by the delivery device 1 is provided. Is preheated by a preheating device 2, and the preheated conductor 8 is covered with a foaming resin by an extruder 3. The electric wire 8a covered with the foaming resin is cooled by a moving cooling water tank 4a and a fixed cooling water tank 4b, and then a take-up machine 5 Then, it is wound on the winder 7 via the accumulator 6.

In this embodiment, the outer diameter of the conductor 8 after preheating, the outer diameter of the electric wire 8a before and after being taken up by the take-off machine 5, and the capacitance are measured by the method for producing a foam insulated wire as described above. The outer diameter of the conductor 8, the outer diameter of the electric wire 8a, the capacitance, and the set value of the dielectric constant of the resin are calculated by the computer 9, and the foaming degree of the foamed resin and the basis weight of the foamed resin are calculated.

Then, the extrusion rotation speed and the take-up speed are controlled by the basis weight control output such that the value of the basis weight of the foamed resin calculated by the measured value becomes the target value of the basis weight of the foamed resin calculated by the set value. Controls the outer diameter of the core.

Further, the extrusion temperature, the cooling rate of the coated wire 8a, the cooling temperature, and the injection of the foaming agent are controlled by the foaming degree control output so that the foaming degree of the foamed resin calculated from the measured value becomes the target value calculated from the set value. The capacitance was controlled as the amount was controlled.

By doing so, the extrusion rotation speed and the take-up speed according to the difference from the target areal weight, the extrusion temperature according to the calculated foaming degree, the cooling speed of the coated electric wire 8a, the cooling temperature, and the injection of the foaming agent. The amount can be controlled, and the core outer diameter (outer diameter of the electric wire 8a) and core capacitance (capacitance of the electric wire 8a) when the coated electric wire 8a (foamed insulated electric wire 8a) is extruded are changed. It is possible to obtain a method for producing a foam insulated wire in which stable extrusion conditions can be easily obtained by minimizing the above.

That is, the outer diameter of the conductor 8 after preheating is measured by the conductor outer diameter measuring device 10 provided between the preheating device 2 and the extruder 3 to measure the capacitance provided between the cooling water tank 4 and the take-up device 5. The core capacitance was measured at a value of 11.

Then, the core outer diameter was measured by the core outer diameter measuring device 12 provided between the take-up machine 5 and the accumulator 6.

The measured values of the conductor outer diameter, the core outer diameter, and the core capacitance measured by the conductor outer diameter measuring device 10, the core outer diameter measuring device 12, and the capacitance measuring device 11 are input to the computer 9, and these input values are The set value input A of the conductor outer diameter, the core outer diameter, the core capacitance, the dielectric constant of the resin, etc. input to the calculator 9 is input to the calculator
Then, the basis weight control output B and the foaming degree control output C are calculated.

By doing so, the extrusion rotation speed and the take-up speed are controlled by the basis weight control output B, and the extrusion temperature, the cooling speed of the electric wire 8a after coating, the cooling temperature, and the injection amount of the foaming agent are controlled by the foaming degree control output C. By controlling, mutual variation between the core outer diameter and the core capacitance can be suppressed, and stable extrusion conditions can be easily obtained.

In the case where the extruder is a method of injecting a foaming agent from the connected portion in the connected twin-screw manufacturing, the first extruder is used for supplying the resin, and the second extruder is used for kneading the resin and the foaming agent. When the present invention is applied to this type of extruder, the basis weight control output B
Control the first extruder.

Since the second extruder rotation speed affects the injection amount of the foaming agent with respect to the resin amount, the foaming degree control output C may be used for the second extruder rotation speed command.

[Advantages of the Invention] As described above, the present invention minimizes fluctuations in the core outer diameter and core capacitance when a foam insulated wire is extruded, and stable extrusion conditions are easily obtained. It is possible to obtain a method for producing a foam insulated electric wire, which minimizes fluctuations in the core outer diameter and the core capacitance when the foam insulated electric wire is extruded and makes it possible to easily obtain stable extrusion conditions.

[Brief description of drawings]

FIG. 1 is a front view of an extrusion molding line according to an embodiment of the method for producing a foam insulated wire of the present invention. 1: Delivery device, 2: Preheating device, 3: Extruder, 4: Cooling water tank, 4a: Moving cooling water tank, 4b: Fixed cooling water tank, 5: Take-up machine, 6: Accumulator, 7: Winding machine, 8: Conductor , 8a: electric wire (coated with foamed resin), 9: calculator, 10: conductor outer diameter measuring device, 11: capacitance measuring device, 12: core outer diameter measuring device.

Claims (1)

[Claims] 1. A delivery device, a preheating device, an extruder, a cooling water tank,
It comprises a take-up machine, an accumulator, and a winding machine, preheats the conductor delivered by the delivery device by the preheating device, coats the preheated conductor with foamed resin by the extruder, and forms an electric wire coated with the foamed resin. In a method for producing a foam insulated wire, which is cooled in the cooling water tank, then taken up by the take-up machine, and then taken up by the winder through the accumulator, a conductor outer diameter provided between the preheating device and the extruder. Measure the outer diameter of the conductor with a measuring device, measure the capacitance of the wire with a capacitance measuring device provided between the cooling water tank and the take-off device, the core provided between the take-up device and the accumulator Measure the outer diameter of the electric wire with an outer diameter measuring instrument, and use these measured values in a calculator with the outer diameters of these conductors, the outer diameter of the electric wire coated with foamed resin, the capacitance, and the dielectric constant of the resin. Enter and calculate the foaming degree of foamed resin and foamed resin in the calculator Calculating the basis weight, the basis weight of the value of the foamed resin obtained from the measured value, the extrusion speed by the basis weight control output such that the target value calculated by the set value,
By controlling the take-up speed, and by using the foaming degree control output so that the value of the foaming degree of the foamed resin obtained from the measured value becomes the target value calculated by the set value, the extrusion temperature and the cooling rate of the electric wire after coating The method for producing a foam insulated wire is characterized in that the cooling temperature and the injection amount of the foaming agent are controlled.