JP2863015B2 - Manufacturing method of metal-coated wire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a metal-coated wire by extrusion-coating a metal tube made of aluminum or the like around an insulating core.

[0002]

2. Description of the Related Art Metal-coated wires in which a core is coated with an insulating core such as foamed polyethylene or the like and a metal tube made of aluminum or the like is coated on the outer periphery of an insulating core are used in various fields.
Often used for coaxial cables such as ATV systems.

A metal-coated wire using, for example, aluminum has been conventionally manufactured as shown in FIG. That is, an insulating core 11 in which a core is covered with an insulator such as foamed polyethylene.
Is introduced into a conform type extruder (friction drive type extruder) 13, and the aluminum tube 17 is extruded by the conform type extruder 13 so that the gap 15 is present on the outer periphery of the insulating core 11.

[0004] The conform type extruder 13 is disclosed in
No. 59-11366, wherein a groove surface of a drive wheel 13a having a groove on an outer peripheral surface and a drive wheel 13a
The aluminum pipe 17 is pushed out by introducing aluminum into a pipeline formed by the inner wall surface of the fixed shoe block 13b engaged with the drive wheel 13a by frictional force with the drive wheel 13a.

Next, the extruded aluminum pipe 17 is cooled in a cooling water tank 19. Then, compressed air is blown onto the surface of the aluminum pipe 17 by the air wiper 21, and the cooling water adhering to the surface is blown off to drain the water. Finally, the diameter of the aluminum tube 17 is reduced by the diameter reducing die 23 to produce the metal-coated wire 25 using aluminum. In the figure, reference numeral 41 denotes a dancer.

[0006]

However, in the above-mentioned conventional manufacturing method, even if the cooling water adhering to the surface of the aluminum pipe is drained with an air wiper, the water remaining on the surface of the aluminum pipe is completely removed. May not be possible. If water remains, the lubricating oil is repelled and a portion where the lubricating oil does not adhere is formed. Therefore, due to insufficient lubrication, seizure between the diameter-reducing die and the aluminum tube is liable to occur, and the diameter may not be reduced.

[0007] If the aluminum tube is wound up and accommodated in a drum or the like with water remaining, the water is trapped and the aluminum tube may be corroded or discolored, resulting in poor appearance or shortened product life. . Furthermore, the temperature of the aluminum tube becomes about 80 ° C. when the diameter is reduced, and the heat causes shrinkage and thermal deterioration of an insulator such as foamed polyethylene, thereby reducing the adhesion to the aluminum tube. Was.

[0008]

SUMMARY OF THE INVENTION The present invention provides a method of manufacturing a metal-coated wire which solves the above-mentioned problems, and comprises a method of extruding a metal tube so that a void is present on the outer periphery of an insulating core. The metal pipe immediately after that is cooled with cooling water, the cooling water adhering to the surface of the metal pipe is drained with an air wiper, and then the diameter is reduced by a diameter reducing die to make the metal pipe closely contact the insulating core. In the wire manufacturing method, after the cooling water is drained, the metal tube is heated and dried, and the metal tube is further passed through a lubricating oil so that the temperature of the metal tube at the time of diameter reduction adversely affects the insulating core. After cooling to a temperature that does not affect
The diameter is reduced by a diameter reducing die.

[0009]

In the present invention, the purpose of heating and drying the metal pipe after draining the cooling water is to completely remove the water remaining on the surface of the metal pipe and to apply the lubricating oil to the entire outer circumference of the metal pipe. This is to prevent seizure between the reduced diameter die and the metal tube. Furthermore, after passing this metal tube through lubricating oil and cooling it to a temperature at which the temperature of the metal tube at the time of diameter reduction does not adversely affect the insulating core, the diameter is reduced by the diameter reducing die because of the heat generated during the diameter reduction. This is because the temperature of the metal tube is suppressed to a desired temperature (for example, 50 ° C. or lower) to prevent thermal contraction and thermal deterioration of the insulating core.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method of manufacturing a metal-coated wire according to the present invention will be described below in detail with reference to FIG. The insulating core 11 in which the core is covered with an insulator such as foamed polyethylene is introduced into the conform type extruder 13, and the aluminum tube 17 is formed by the conform type extruder 13 so that a void is present on the outer periphery of the insulating core 11. Extrude. In this case, the outer diameter of the insulation core is 8.5m
m, the outer diameter of the aluminum tube is 13 mm, the inner diameter is 11.7 mm,
The extrusion temperature of the aluminum tube is 430 ° C and the extrusion speed is 50m /
Minutes.

The extruded aluminum tube 17 is a cooling water tank.
Enter 19 and cool to about 35 ° C with cooling water kept at about 25 ° C. At this time, the temperature of the aluminum pipe 17 to be cooled is monitored by a radiation thermometer (not shown) at the outlet side of the cooling water tank 19, and is automatically adjusted by adjusting the position of the weir 19a of the cooling water tank 19. Maximum effective length of aquarium 19 is 1
m to a minimum of 50 cm so that the temperature of the aluminum pipe 17 at the outlet of the cooling water tank is maintained at about 35 ° C.

Thereafter, the aluminum pipe 17 passes through three nozzle-type air wipers 21 installed at a distance of 50 cm or more,
Then, compressed air is sprayed onto the surface of the aluminum pipe 17 to drain the cooling water. The first-stage air wiper removes large water droplets adhering to the surface of the aluminum tube 17, and the second-stage air wiper removes water droplets that were missed in the first stage and the thickness of the water film on the surface of the tube. And the third-stage air wiper removes the water film as much as possible.

However, since the moisture cannot be completely removed by the air wiper alone, the aluminum pipe 17 is then placed in a hot air blower.
Hot air heated to about 80 ° C. by 27 is passed through a hot air sleeve 29 flowing at a rate of 5 m ³ / min. As a result, the aluminum tube 17 is heated to about 50 ° C., and the water adhering to the surface is completely removed.

Further, after passing the aluminum pipe 17 through a lubricating oil tank 31 having a length of about 50 cm filled with lubricating oil whose temperature is controlled to about 20 ° C., a reduced-diameter die 23 installed at the rear end of the lubricating oil tank 31 Reduces the outer diameter of the aluminum tube 17 to 9.5 mm,
The metal-coated wire 25 using aluminum is manufactured.

The lubricating oil in the lubricating oil tank 31 overflows to the side opposite to the side where the reduced-diameter die is installed.
7. Circulating in the route of the lubricating oil tank 31 (the pump is not shown). A heat exchanger 39 is installed in the pipe 37, and lubricating oil is passed through the heat exchanger 39 at a flow rate of 5 liter / min.
Temperature control.

When the aluminum pipe 17 is passed through a lubricating oil at about 20 ° C., the temperature of the aluminum pipe at the time of diameter reduction, which was conventionally about 80 ° C., can be suppressed to 50 ° C. or less. As a result, thermal contraction and thermal degradation of the insulating core can be prevented. Further, since the surface of the aluminum tube 17 is completely removed from the water, the lubricating oil adheres to the entire surface, and the seizure between the reduced diameter die and the aluminum tube does not occur.

According to the results of testing the manufactured metal-coated wire, when an insulating core having an outer diameter of 8.5 mm was used, the length was 30 cm.
The force required to pull out the insulating core from the 9.5 mm outer diameter aluminum tube after diameter reduction was conventionally 10 kgf or less, but this method has been improved to 30 kgf or more. This means that there is no heat shrinkage of the foamed polyethylene, and the aluminum tube and the foamed polyethylene are surely in close contact.

In the above embodiment, the lubricating oil temperature was set to about 20
However, experiments have confirmed that the temperature of the lubricating oil should be set to 30 ° C. or less in order to keep the temperature of the aluminum tube at the time of diameter reduction to 50 ° C. or less. Also, the above embodiment is
This is a case where an aluminum tube is used as a metal tube and a polyethylene foam is used as an insulator, but the present invention can be similarly applied to the manufacture of other metal-coated wires.

[0019]

As described above, the present invention extrudes a metal tube on the outer periphery of an insulating core when manufacturing a metal-coated wire.
After cooling the metal pipe with cooling water, draining the cooling water attached to the surface of the metal pipe with an air wiper, and then heating and drying the metal pipe, the moisture remaining on the surface of the metal pipe is completely removed. can do. Therefore, seizure of the metal tube and the reduced-diameter die can be prevented. Further, the metal pipe is passed through lubricating oil, cooled to a temperature at which the diameter of the metal pipe at the time of diameter reduction does not adversely affect the insulating core, and then reduced by a diameter reducing die. Can be suppressed to a desired temperature (for example, 50 ° C. or lower), and thermal contraction and thermal degradation of the insulating core can be prevented. Therefore,
A good metal-coated wire in which the insulating core and the metal tube are in close contact can be manufactured.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a method for manufacturing a metal-coated wire according to one embodiment of the present invention.

FIG. 2 is an explanatory view of a conventional method of manufacturing a metal-coated wire.

[Explanation of symbols]

 11 Insulation core 13 Conform extruder 17 Aluminum tube 19 Cooling water tank 21 Air wiper 23 Reduced diameter die 25 Metal-coated wire 29 Hot air sleeve 31 Lubricating oil tank 33, 37 Pipe 35 Lubricating oil tank 39 Heat exchanger

Claims (1)

(57) [Claims] 1. A metal pipe is extruded so that a void is present on the outer periphery of an insulating core, and the metal pipe immediately after the metal pipe is cooled with cooling water, and cooling water attached to the surface of the metal pipe is drained by an air wiper. Then, in the method of manufacturing a metal-coated wire to reduce the diameter by a diameter reducing die to bring the metal tube into close contact with the insulating core, after draining the cooling water, the metal tube is heated and dried, and the metal tube is further dried. A method for producing a metal-coated wire, comprising passing through a lubricating oil, cooling the metal tube at the time of diameter reduction to a temperature that does not adversely affect the insulating core, and then reducing the diameter with a diameter reducing die.