JP4136097B2 - Low noise coaxial cable and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a low-noise coaxial cable and a method for manufacturing the same, and particularly to a low-noise coaxial cable having a good flexibility and easy terminal processing and a method for manufacturing the same.
[0002]
[Prior art]
Conventionally, for example, sliding occurs between the outer conductor of the coaxial cable and the dielectric due to bending or mechanical vibration of the coaxial cable, and as a result, an electrostatic charge is generated to transmit the coaxial cable. The characteristics may be adversely affected. In order to prevent this adverse effect, a low-noise coaxial cable has been proposed. This low-noise coaxial cable is provided with a semiconductive layer between the outer conductor layer and the dielectric layer of the coaxial cable, and further these In order to prevent sliding between the layers, the layers are tightly adhered to each other, so that the flexibility of the coaxial cable is poor, and the coaxial cable is The removal of the semiconductive layer performed during the terminal processing is also difficult and time consuming, and the terminal processing is troublesome.
[0003]
In the above-described low noise coaxial cable, for example, a coaxial cable capable of high-speed signal transmission has been proposed so far. In such a coaxial cable, a dielectric as a dielectric covering the inner conductor is used. Polytetrafluoroethylene, which has a low rate, is coated around the inner conductor, and the semiconductive layer provided between the dielectric and the outer conductor is conductive in the porous portion of the porous polytetrafluoroethylene tape. A tape made semiconductive by mixing carbon powder or carbon fiber is wound around the dielectric, then sintered and completely fused to form a low noise coaxial cable. As a result, the cable is not flexible enough to remove the semiconductive layer from the dielectric even when the end treatment is performed. Or It takes a long time by using the Kezugu, etc., it was also difficult the work. In particular, the above-described low-noise coaxial cable with a small diameter has a problem that it takes a very long time to process the terminal and the operation becomes very difficult.
[0004]
[Problems to be solved by the invention]
Therefore, the present invention has been made to solve the above-described problems of the prior art, and its purpose is to enable high-speed signal transmission, low flexibility without sacrificing flexibility, and easy terminal processing. To provide a coaxial cable.
[0005]
[Means for Solving the Problems]
The above object is achieved by a low noise coaxial cable and a method for manufacturing the same according to the present invention. That is, in summary, the present invention relates to an inner conductor, a dielectric layer coated around the inner conductor, a semiconductive layer formed around the dielectric layer, and a periphery of the semiconductive layer. In a low-noise coaxial cable including an outer conductor layer to be formed and a jacket coated around the outer conductor layer, the dielectric layer is made of polytetrafluoroethylene, and the semiconductive layer is formed of the dielectric layer. Around the periphery is formed by winding a plastically deformable green or semi-fired semiconductive porous polytetrafluoroethylene tape, and the outer conductor layer is embedded in the plastically deformable semiconductive layer , a low noise coaxial cable, characterized in that the outer conductor layer and the semiconductive layer is in close contact with the dielectric layer, the present invention includes the steps of preparing an inner conductor, around the inner conductor A step of covering the collector layer, forming a dielectric layer semiconductive layer by winding a tape of semiconductive porous polytetrafluoroethylene plastically deformable green or semi-sintered around, Forming an external conductor layer around the semiconductive layer; and squeezing the external conductor layer from the outside to embed the external conductor layer in the semiconductive layer so that the external conductor layer and the semiconductive layer are A method for manufacturing a low-noise coaxial cable, comprising: a step of closely contacting a dielectric layer; and a step of covering a jacket around the outer conductor layer.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
In the low-noise coaxial cable 1 according to the present invention, the outer conductor layer is squeezed from the outside without sintering the semiconductive layer, and the outer conductor layer can be plastically deformed because of the unfired or semi-fired EPTFE tape. As a result, the semiconductive layer and the outer conductor layer are kept in close contact with the dielectric layer, so that when the end treatment is performed, it is formed by winding the tape. When the semiconductive layer is unwound from the dielectric layer, it can be easily removed without requiring a special tool or apparatus, and the terminal treatment can be performed very easily.
Furthermore, in this low-noise coaxial cable, as described above, the semiconductive layer is not baked to be fused to the dielectric layer, and therefore the flexibility is not impaired.
[0007]
【Example】
The present invention will be described below with reference to the accompanying drawings on the basis of one embodiment thereof.
FIG. 1 is a cross-sectional view of an embodiment of a low noise coaxial cable according to the present invention.
Referring to FIG. 1, a low noise coaxial cable 10 according to the present invention is shown in FIG. 1, and this low noise coaxial cable 10 is composed of an inner conductor 2 (in this embodiment, silver having an outer diameter of 0.17 mm). A dielectric layer 3 formed by extruding and coating polytetrafluoroethylene having a low dielectric constant is provided around (7 twists of plated copper-coated steel wire) (in this embodiment, an outer diameter of 1.3 mm).
[0008]
Around this dielectric layer 3, an unsintered or semi-sintered EPTFE tape in which conductive carbon powder or carbon fiber is mixed into a porous part of a porous polytetrafluoroethylene (EPTFE) tape to make it semiconductive. A semiconductive layer 4 (in this embodiment, a thickness of 0.2 mm) is formed by winding (in this embodiment, a width of 5 mm and a thickness of 0.1 mm). An outer conductor layer 5 (in this embodiment, 43 silver-plated annealed copper wires having an outer diameter of 0.12 mm and an outer diameter of 1.84 mm) in which a conductor wire is wound horizontally is formed.
[0009]
Thereafter, the formed outer conductor layer 5 is squeezed from the outside using a die (not shown) or the like, and the outer conductor layer 5 can be plastically deformed because of an unfired or semi-fired EPTFE tape. Embedded in the semiconductive layer 4, and as a result, the semiconductive layer 4 and the external conductor layer 5 are brought into close contact with the dielectric layer 3 and maintained there. A low-noise coaxial cable 10 is formed by covering a hexafluoropropylene copolymer (FEP) to form a jacket 6 (in this embodiment, a thickness of 0.2 mm).
[0010]
In the low-noise coaxial cable 10 configured as described above, when the end processing is performed, the jacket 6 having a desired length is removed from the end of the cable 10 and then embedded in the semiconductive layer 4. The outer conductive layer 5 is removed from the semiconductive layer 4 and bundled, folded in a predetermined direction, and then unwound the semiconductive layer 4 formed by winding the tape, so that the dielectric is formed by the embedded external conductor 5. A special tool or device is required from the dielectric layer 3 to the semiconductive layer 4 of the so-called green tape that has been pressed against and closely adhered to the body layer 3, that is, the unfired or semi-fired EPTFE tape. Therefore, the terminal processing can be performed very easily.
[0011]
Further, in this low-noise coaxial cable 10, the semiconductive layer 4 of the unfired or semi-fired EPTFE tape is adhered to the dielectric layer 3 together with the external conductor layer 5 by ironing from the outside of the external conductor layer 5. Thus, since it is maintained there, firing to be fused to the dielectric layer 3 is not performed, and therefore flexibility is not impaired.
[0012]
In order to measure the noise charge amount of the low-noise coaxial cable having the above configuration according to the present invention, when a cable length of 2 m was used as a sample and vibration with an amplitude of 5 mm and a frequency of 20 Hz was added, the noise charge amount was 7 pC ( Pico Coulomb). As a comparative example, when the noise charge amount of a device without the semiconductive layer 4 of the present invention was measured under the same conditions, the noise charge amount was 1000 pC (picocoulomb). It will be understood that the amount of noise charge is sufficiently reduced.
[0013]
【The invention's effect】
As described above, according to the low-noise coaxial cable of the present invention, polytetrafluoroethylene having a low dielectric constant is used for the dielectric layer and the semiconductive layer, so that high-speed signal transmission is possible. Since the layer is not fired into a dielectric layer, the semiconductive layer can be easily removed from the dielectric layer without the need for special tools or equipment, and the terminal treatment can be performed very easily. There is an effect that flexibility is not impaired.
[0014]
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an embodiment of a low noise coaxial cable according to the present invention.
[Explanation of symbols]
2: inner conductor, 3: dielectric layer,
4: semiconductive layer, 5: outer conductor layer,
6: Jacket, 10: Low noise coaxial cable.

Claims (2)

An inner conductor, a dielectric layer coated around the inner conductor, a semiconductive layer formed around the dielectric layer, an outer conductor layer formed around the semiconductive layer, and the outer In a low-noise coaxial cable having a jacket coated around a conductor layer, the dielectric layer is made of polytetrafluoroethylene, and the semiconductive layer is unfired or plastically deformable around the dielectric layer. Formed by winding a semi-baked semiconductive porous polytetrafluoroethylene tape, the outer conductor layer is embedded in the plastically deformable semiconductive layer, and the outer conductor layer and the semiconductive layer are A low-noise coaxial cable characterized by being in close contact with a dielectric layer. A step of preparing an inner conductor, a step of coating a dielectric layer around the inner conductor, and an unfired or semi-fired semiconductive porous polytetrafluoroethylene that can be plastically deformed around the dielectric layer . A step of winding a tape to form a semiconductive layer, a step of forming an external conductor layer around the semiconductive layer, and squeezing the external conductor layer from the outside to convert the external conductor layer into the semiconductive layer A method of manufacturing a low-noise coaxial cable, comprising: embedding and adhering the outer conductor layer and the semiconductive layer to the dielectric layer; and covering a jacket around the outer conductor layer. .

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