JPH03127409A - Shield cable - Google Patents

Abstract

PURPOSE:To obtain excellent shielding effect by coating the circumference of a core wire with an insulating sleeve comprising a resin including magnetic powder by not less than a specified ratio, and with a shield conductor comprising a conductive resin, to which a drain wire is connected. CONSTITUTION:An insulating sleeve 3 for coating the circumference of a core wire 2 is formed out of an insulating resin including no less than 50weight% of magnetic powder 4, into a tube shape. A shield conductor 5 for coating the circumference of the sleeve 3 is formed out of a conductive resin, into a tube shape, with a drain wire 6 comprising a conductor, buried inside in a longitudinal direction. A wire 1 formed in this manner is used after the wire 6 is grounded. For the use, when electric power is fed, a radiant noise generated by the core wire 2 is absorbed in the magnetic powder 4 in the sleeve 3. Since no less than 50weght% of magnetic powder 4 is included in the sleeve 3, absorption of electromagnetic wave is excellent, and a leaking electromagnetic wave is shielded due to the electrostatic shield effect of the conductor 5.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a shielded cable in which a core wire is coated with a shielded conductor.

[Conventional technology]

In shielded cables, the core wire is covered with a shield conductor such as a mesh tube through an insulator, so that radiated noise generated from the core wire is reflected inward by the electrostatic shield and prevented from leaking to the outside. In such a shielded cable, current leaking from the core wire flows through the shielded conductor and radiates noise from the shielded conductor to the outside.

In order to prevent noise from being generated from such a shield conductor, there are two types of shield conductors: ferrite powder coated around the shield conductor (Japanese Patent Laid-open No. 190611/1983), and ferrite-containing rubber coated around the shield conductor. (Japanese Unexamined Patent Publication No. 48-77390) has been proposed.

[Problem to be solved by the invention]

However, such conventional shielded cables do not have a sufficient shielding effect, and since a mesh tube is used as the shield conductor, there are problems such as the manufacturing process becomes complicated to cover the cable completely in the form of a tube. was there.

This invention was made to solve the above-mentioned problems, and aims to provide a shielded cable that has an excellent electromagnetic shielding effect and is easy to manufacture.

[Means to solve the problem]

The shielded cable of the present invention includes an insulating sleeve made of resin containing 50% by weight or more of magnetic powder and a shielded conductor made of conductive resin to which a drain wire is connected so as to cover the core wire. .

[For production]

The shielded cable of the present invention grounds the drain wire and uses the shielded conductor as an electrostatic shield. In use, the insulating sleeve containing magnetic powder absorbs electromagnetic waves leaking from the core wire or shield conductor. In this case, since the shield conductor contains 50% by weight or more of magnetic powder in the resin, the electromagnetic wave absorption effect is high and leakage of electromagnetic waves is eliminated.

Furthermore, since the shield conductor is made of conductive resin, it can be easily molded into a complete tube shape, and the electrostatic shielding effect is enhanced.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 to 3 are perspective views each showing another embodiment of the present invention.

In Figure 1, (1) is a shielded cable, (2) is a core wire made of a conductor such as copper, and (3) is an insulating sleeve that covers the core wire (2), which contains 50% by weight or more of ferrite. It is formed into a tube shape from an insulating resin containing magnetic powder (4) such as. (5) is an insulating sleeve (
3) is a shield conductor that covers the periphery and is formed into a tube shape from conductive resin, and a drain wire (6) made of a conductor is buried inside in the longitudinal direction.

The shielded cable (1) configured as described above is used with the drain wire (6) grounded. In use, when power is supplied to the core wire (2), radiant noise generated from the core wire (2) is absorbed by the magnetic powder (4) in the insulating sleeve (3). In this case, the insulating sleeve (3) is made of magnetic powder (4)
Because it contains more than 50% by weight.

It has excellent electromagnetic wave absorption properties and is not very likely to leak to the outside, but leaking electromagnetic waves are shielded by the electrostatic shielding effect of the shield conductor (5).

In the embodiment shown in FIG. 2, an insulating sleeve (7) made of an insulating resin containing magnetic powder (4) is formed to further cover the shield conductor (5) shown in FIG. 1.

In this embodiment, the electromagnetic waves radiated from the shield conductor (5) are further absorbed by the insulating sleeve (7), and leakage of electromagnetic waves to the outside is almost completely eliminated.

In the embodiment shown in Fig. 3, the core wire (2) and the shield conductor (5)
An insulating sleeve (8) made of an insulating resin containing no magnetic powder (4) is formed between the shield conductor (5) and the shield conductor (5).
An insulating sleeve (7) made of an insulating resin containing magnetic powder (4) is formed around the insulating sleeve (7).

In this embodiment, the radiation noise generated from the core wire (2) is shielded by the shield conductor (5).
) is shielded by the insulating sleeve (7).

Fig. 4 is an impedance characteristic diagram of the shielded cable (1), in which curve A is the impedance characteristic of the shielded cable (1) in Figs. The impedance characteristics of (1,) are shown.

As shown in Figures 1 and 2, a shielded cable (1) in which an insulating sleeve (3) containing magnetic powder (4) is interposed between a core wire (2) and a shielded conductor (5) is capable of handling electromagnetic waves. In addition to absorbing noise, it reduces the impedance of the shielded cable (1) itself, and in a certain frequency range, there is no difference in impedance depending on the frequency, making impedance matching easier and eliminating practical restrictions.

In addition, although the said Example showed the case where the core wire (2) was one single wire, the same effect is shown also when there are multiple core wires (2).

〔Effect of the invention〕

As described above, according to the present invention, an insulating sleeve made of resin containing 50% by weight or more of magnetic powder and a shield conductor made of conductive resin connected to a drain wire are provided so as to cover the core wire. Therefore, a shielded cable that has an excellent electromagnetic shielding effect and is easy to manufacture can be obtained.

[Brief explanation of the drawing]

1 to 3 are perspective views of the shielded cable of the embodiment, and FIG. 4 is an impedance characteristic diagram. In each figure, the same reference numerals indicate the same or corresponding parts, (1)
is shielded cable, (2) is core wire, (3), (7),
(8) is an insulating sleeve, (4) is a magnetic powder, (5) is a shield conductor, and (6) is a drain wire.

Claims (1)

[Claims] (1) A shielded cable characterized by comprising an insulating sleeve made of a resin containing 50% by weight or more of magnetic powder and a shielded conductor made of a conductive resin to which a drain wire is connected so as to cover the core wire. .