JP3010926B2 - Insulated cable - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a coated cable used for connection inside and between various electronic devices, and more particularly, to a coating provided with a structure for preventing transmission of electromagnetic noise and radiation to the outside. About the cable.

[0002]

2. Description of the Related Art Conventionally, various cables have been used for wiring inside electronic devices and for connecting electronic devices. This type of cable includes a non-shield type cable in which an insulating coating layer is formed around a core wire and a shield type cable in which an electromagnetic shielding layer is further provided outside the insulating coating layer around the core wire. In the former non-shielded type cable, as shown in FIG.
When the core wire b is connected to the connector 3 of the electronic device 2,
There has been a problem that noise is transmitted through the core wires of the cables 1a and 1b, or electromagnetic noise is radiated to the surroundings as indicated by an arrow A.

On the other hand, a shield type cable 4 shown in FIG. 5 has a structure in which an insulating coating layer 4b, an electromagnetic shielding layer 4c made of a metal braid, and an insulating coating layer 4d are provided on the outer periphery of a core wire 4a. This shield type cable 4
, An electromagnetic shield layer 4c is provided on the outside, and the electromagnetic shield layer 4c is used so as to be connected to a reference potential. Therefore, it is possible to prevent radiation of electromagnetic wave noise outside the cable 4 for the time being.

[0004]

However, as shown in FIG. 6, a connector 5 provided in electronic devices 5 and 6 is provided.
When the cables 4a and 6a are connected by the cable 4, electromagnetic noise may be radiated to the surroundings as shown by the arrow A. That is, the reference potentials of the connected electronic devices 5 and 6 are not always equal, and if they are different, a current flows through the electromagnetic shield layer 4c, and electromagnetic noise is radiated to the surroundings. was there. as a result,
Even if the shield type cable 4 is used, the radiation of electromagnetic wave noise to the surroundings cannot be reliably prevented, which may cause malfunction of peripheral devices and deterioration of characteristics. An object of the present invention is to not only prevent transmission of noise to connected devices or components, but also to reliably suppress radiation of electromagnetic wave noise to surroundings.
It is to provide a coated cable.

[0005]

SUMMARY OF THE INVENTION The present invention relates to
The insulating coating layer and the conductive coating layer are formed in this order.
And a core wire made of a conductive material,
An insulating cover layer made of an insulating resin provided outside of the core wire, the resistance value between the is provided outside the insulating coating layer, a conductive resin only than-than both end 1Ω~100kΩ
Have a resistance, a sheathed cable, characterized in that it comprises a conductive coating layer which is connected to a reference potential.

[0006]

Since the conductive coating layer is provided on the outside of the core wire via the insulating coating layer, the conductive coating layer is connected to the reference potential, so that electromagnetic noise is radiated to the surroundings by the electromagnetic shielding effect. Can be prevented. Moreover, the conductive coating layer has a resistance between both ends of 1 Ω to 100 kΩ.
Therefore, even when the reference potential is different between the electronic devices connected to both ends, the current flowing through the conductive coating layer is suppressed by the resistance of the conductive coating layer. Therefore, radiation of electromagnetic wave noise to the surroundings is suppressed.

[0007] Further, since the core wire and the conductive resin layer overlap with each other via the insulating coating layer, the LC filter is distributed over the entire length of the cable by the inductance of the core wire and the capacitance formed by the insulating coating layer. It is composed. Therefore, the electromagnetic wave noise passing through the core wire is dropped to the conductive coating layer that is to be connected to the reference potential, so that the transmission of the electromagnetic wave noise via the core wire can be reliably prevented.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be clarified by describing non-limiting embodiments of the present invention. 1 and 2 are a perspective view and a cross-sectional view showing a covered cable according to one embodiment of the present invention. The insulated cable 11 is made of a core wire 1 made of a conductive material having good conductivity, such as gold, silver, or copper.
2 is provided. An insulating coating layer 13 made of an insulating resin is formed outside the core wire 12.

The insulating coating layer 13 includes a conductive coating layer 14 described later.
In addition to providing electrical insulation between the core wire 12 and the core wire 12, the capacitor is provided between the core wire 12 and the conductive coating layer 14 in a distributed constant manner over the entire length of the coated cable 11. This insulating coating layer 13 needs to be formed relatively thin in order to constitute the capacitor.

In the wiring in the device, the capacitance component constituted by the insulating coating layer 13 is about 100 pF to about 100 pF.
Although it is preferable to configure a capacitance of about 0 pF, the length of a coated cable used for wiring in equipment is usually 15 cm.
It is about. Therefore, in order to realize the above capacitance value in the covered cable 11 having a length of about 15 cm, the insulating coating layer 1
In the case where 3 is made of a vinyl chloride resin or the like having a relative dielectric constant of about ε = 4, the thickness of the insulating coating layer 13 may be about 0.1 mm. Further, in a cable used for connection between devices, it is preferable that a capacitance value of about 500 to 1000 pF is configured by the insulating coating layer 13 in order to absorb noise. On the other hand, the length of a coated cable used for connection between devices is usually about 1 m. Therefore, the insulating coating layer 1 is made of an insulating resin of about ε = 4 such as a vinyl chloride resin.
In the case of forming No. 3, the thickness of the coating layer may be about 0.1 mm similarly to the above, and a capacity of about 600 pF can be formed, which is preferable.

As described above, the insulating coating layer 13 is disposed between the core wire 12 and the conductive coating layer 14 to form a capacitor. However, the insulating coating layer 13 has a required capacitance, that is, a preferable capacitance value for noise removal. Next, the thickness of the insulating coating layer 13 and the insulating resin constituting the insulating coating layer 13 may be selected. A conductive coating layer 14 made of a conductive resin is provided outside the insulating coating layer 13. The conductive coating layer 14 is made of a material having a resistance in which carbon powder or the like is dispersed in a conductive resin, and has a resistance value of 1Ω to 1 between both ends.
It is configured to have a resistance value in the range of 00 kΩ.

Accordingly, in the coated cable 11 of the present embodiment, the resistors R _{1 to} R ₄ are added to the LC filter shown in the circuit diagram of FIG.
Are realized. Referring to FIG. 3, inductances L _{1 to} L ₄ are formed by core wire 11,
Capacitor C ₁ -C ₄ is configured by the insulating cover layer 13 and the dielectric. On the other hand, resistors R _{1 to} R
₄ is composed of the conductive coating layer 14. Note that an insulating coating layer 15 made of an insulating material such as a vinyl chloride resin is formed outside the conductive coating layer 14.

In the coated cable 11 of this embodiment, a large number of LC filters are arranged in a distributed manner over the entire length, so that the electromagnetic wave noise superimposed on the core wire 12 is connected to the conductive coating layer 14 connected to the reference potential. Is dropped. On the other hand, since the conductive coating layer 14 is formed on the outer peripheral side, radiation of electromagnetic noise to the outside is prevented by the electromagnetic shielding action of the conductive coating layer 14. Moreover, since the conductive coating layer 14 is made of a material having resistance as described above,
Unlike the reference potential between the apparatuses connected, even when a current flows through the conductive coating layer 14, the resistor R ₁ to R ₄
Accordingly, the current is suppressed, and therefore, radiation of electromagnetic wave noise to the surroundings and transmission of electromagnetic wave noise between devices can be reliably prevented.

The conductive coating layer 14 can be easily formed by a method of dispersing a carbon powder in a conductive resin or a method of dispersing a metal powder in a resin. Also, the insulating coating layer 13 can be made of an appropriate insulating resin such as polyethylene and fluorine resin, in addition to the above-mentioned vinyl chloride resin.

[0015]

According to the coated cable of the present invention, a large number of LC filters are distributed over the entire length of the coated cable by the core wire made of a conductive material and the core wire and the conductive coating layer provided via the insulating coating layer. Are located in Therefore, electromagnetic wave noise superimposed on the current flowing through the core wire is reliably dropped on the conductive coating layer connected to the reference potential.

Further, since the conductive coating layer is provided on the outer peripheral side, radiation of electromagnetic noise to the outside can be prevented by the electromagnetic shielding effect of the conductive coating layer. Not only that, the conductive coating layer has a resistance value between 1 Ω and
Since it is configured to have a resistance value of 100 kΩ, even when a reference potential differs between connected devices and a current flows through the conductive coating layer, the flow of the current is suppressed by the above-described resistance. Therefore, transmission of noise current via the conductive coating layer and radiation of electromagnetic wave noise outside the conductive coating layer can be reliably prevented.

Further, the coated cable of the present invention is constituted by forming at least the above-mentioned core wire, insulating coating layer and conductive coating layer, and the conductive coating layer is easily formed by dispersing a resistive material in a conductive resin. It is formed. That is,
It can be formed very easily as compared with an electromagnetic shield layer composed of a conventionally used metal braided wire. Therefore, a coated cable that can effectively prevent noise transmission and radiation to the surroundings as described above can be provided at low cost.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing a covered cable of an embodiment.

FIG. 2 is a partially cutaway sectional view showing a covered cable of the embodiment.

FIG. 3 is a diagram showing a circuit configuration of the coated cable of the embodiment.

FIG. 4 is a partially cutaway sectional view for explaining a problem when a conventional coated cable is connected to a device.

FIG. 5 is a partially cutaway perspective view showing an example of a conventional covered cable.

6 is a partially cutaway cross-sectional view for explaining a problem when the devices are connected with the coated cable shown in FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Insulated cable 12 ... Core wire 13 ... Insulation coating layer 14 ... Conductive coating layer

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01B 11/06 H01B 11/08 H01B 7/18

Claims (1)

(57) [Claims] 1. An insulating coating layer and a conductive coating around a core wire.
A coated cable in which layers are formed in this order, a core wire made of a conductive material, an insulating coating layer provided outside the core wire, and made of an insulating resin, and an outside of the insulating coating layer. is provided, the conductive resin
It consists only, the resistance value between both ends have a resistance 1Omu～100keiomega, characterized in that it comprises a conductive coating layer which is connected to a reference potential, sheathed cable.