JPS6110264Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention relates to improvements in shielded wires. Conventionally, this type of shielded wire used annealed copper wire (or tinned annealed copper wire) as the shielding material, but recently, as audio equipment becomes more sophisticated, electromagnetic induction (power frequency and The harmonics (or the rotational frequency of the motor and its harmonics) are viewed as problems. In order to solve this problem, it is necessary to use a material with a high relative magnetic permeability as the shielding material, which is impossible with an annealed copper wire whose relative magnetic permeability is approximately 1. Furthermore, simply using a wire with a high relative magnetic permeability will result in a lower low frequency electromagnetic shielding effect than an annealed copper wire if the terminal impedance is low. This proposal was devised for the purpose of solving the above problems. The embodiments shown in the drawings will be described below. The figure is an enlarged sectional view of an embodiment of the shielded wire according to the present invention, in which 1 is an insulator core, 11 is a conductor, 12 is an insulator, 2 is a shield, and 3 is an outer jacket. The shield 2 uses a nickel-plated iron wire and annealed copper wire having a high magnetic permeability of 90 or more. The shield of the present invention has a so-called horizontally wound structure in which the above-mentioned annealed copper wire and nickel-plated iron wire are spirally wound in parallel in one direction, or a plurality of each strand is wound in parallel. It has a so-called braided structure in which the wires are woven in a crisscross pattern, and in either case of horizontal winding or braiding, the ratio of the number of strands of annealed copper wire and nickel-plated iron wire is approximately 1:2. It is optional to plate the wire with a metal such as tin. Note that the number of insulated conductors is not limited to one as in the above-mentioned embodiments, but there is also a case in which a shield and an outer cover are provided on a plurality of insulated conductors. Next, an experimental example of the proposed shielded wire will be shown. (1) Measurement method A frequency of 200Hg is applied to the coil used as an induction source.
A current of 50 gauss is applied to produce an induced magnetic field of 50 gauss. The induced voltage is measured when a current is placed across the magnetic field and the impedance at the end is changed. (2) Wire sample A horizontally wound shield with a surface density of 95% of the following surface material and configuration is applied on an insulator core with an outer diameter of 1.0 mmφ made by extruding cross-linked polyethylene on an annealed copper wire conductor of size AWG28, and then This is a 0.25mm vinyl chloride jacket with an outer diameter of 2.0mm. (3) Actual measured values are as shown in the table below. Electric wire sample 2 is based on the invention of the present application.

[Table] From the above table, it is recognized that a shielded wire with a ratio of the number of strands of annealed copper wire to nickel-plated iron wire of about 1:2 has a stable low-frequency electromagnetic shielding effect against fluctuations in terminal impedance. This can be said to have a wide range of applicability to actually used circuits. The shielded wire according to the present invention as described above has advantages such as excellent low-frequency electromagnetic shielding effect and excellent electrostatic shielding effect due to the high conductivity of the copper wire.

[Brief explanation of the drawing]

The figure shows an enlarged cross section of a shielded wire in which the present invention was implemented. 1 is an insulator core, 11 is a conductor, 12 is an insulator, 2 is a shield, and 3 is an outer jacket.

Claims (1)

[Claims for Utility Model Registration] A shielded wire in which a shield and an outer sheath are successively provided on one or more insulated conductors, the shield being an annealed copper wire and a nickel-plated iron wire having a relative magnetic permeability of 90 or more. A shielded electric wire comprising: braided or horizontally wound; the number of strands of the braided or horizontally wound annealed copper wire and nickel plated iron wire is approximately 1:2.