CN213877623U

CN213877623U - Shielded cable

Info

Publication number: CN213877623U
Application number: CN202022563678.4U
Authority: CN
Inventors: 张裕仕
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-11-09
Filing date: 2020-11-09
Publication date: 2021-08-03
Anticipated expiration: 2030-11-09

Abstract

A shielded cable having: the cable comprises a first core wire, a first inner liner layer tightly wrapping the first core wire along the length direction, a first shielding layer tightly wrapping the outer surface of the first inner liner layer along the length direction, a second core wire which is parallel to the first core wire and is arranged outside the first shielding layer, a second inner liner layer tightly wrapping the first shielding layer and the second core wire along the length direction, a second shielding layer tightly wrapping the outer surface of the second inner liner layer along the length direction, and an outer sheath tightly wrapping the second shielding layer along the length direction; the second core wire is twisted on the first shielding layer and forms electric contact with the first shielding layer, the first shielding layer and the second shielding layer adopt metal woven meshes, the first inner lining layer and the second inner lining layer adopt soft insulating materials with a damping effect, and the outer sheath adopts insulating rubber or plastic materials. The second core wire is twisted on the first shielding layer, thereby suppressing the characteristic impedance change, improving the problems of signal loss and waveform distortion, and reducing the transmission loss.

Description

Shielded cable

Technical Field

The utility model relates to the technical field of cables, specifically a shielded cable.

Background

Cables are the most important factor causing electromagnetic compatibility problems in systems, and in practical applications it is often found that: after the external pulling cable on the equipment is taken down, the equipment can pass the test smoothly, or when the electromagnetic interference is met on the site, the fault phenomenon is eliminated immediately as long as the cable is pulled down. One of the main reasons for this is that signal crosstalk occurs between the conductors due to the large fractional capacitance and mutual inductance between the conductors in the cable, causing signal loss and waveform distortion, and increasing transmission loss.

Currently, one of the main means for solving the above problems in the industry is to shield the cable. There are many cable structures using shielding technology in the prior art, and the industry is still continuously researching and developing the technical innovation of shielding cables in order to obtain more ideal shielding technology.

SUMMERY OF THE UTILITY MODEL

The utility model aims at satisfying the demand of above-mentioned prior art, provide a shielded cable with novel shielding technique. In order to achieve the above purpose, the present invention adopts the following technical solution.

A shielded cable having:

the cable comprises a first core wire, a first inner liner layer tightly wrapping the first core wire along the length direction, a first shielding layer tightly wrapping the outer surface of the first inner liner layer along the length direction, a second core wire which is parallel to the first core wire and is arranged outside the first shielding layer, a second inner liner layer tightly wrapping the first shielding layer and the second core wire along the length direction, a second shielding layer tightly wrapping the outer surface of the second inner liner layer along the length direction, and an outer sheath tightly wrapping the second shielding layer along the length direction;

the first shielding layer and the second shielding layer adopt metal woven meshes, and the second core wire is twisted on the first shielding layer and forms electric contact with the first shielding layer; the first lining layer and the second lining layer are made of soft insulating materials with a damping effect, and the outer sheath is made of insulating rubber or plastic materials.

Compared with the prior art, the beneficial effects of the utility model reside in that: the second core wire is twisted on the first shielding layer to form electric contact with the first shielding layer, so that the characteristic impedance change is restrained, the problems of signal loss and waveform distortion caused by the interference of inductance and capacitance of the traditional cable are solved, and the transmission loss is reduced.

The invention is further described with reference to the drawings and the detailed description.

Drawings

Fig. 1 is a schematic structural diagram of a first embodiment of the present invention.

Fig. 2 is a schematic structural diagram of a second embodiment of the present invention.

Fig. 3 is a schematic structural diagram of a third embodiment of the present invention.

Detailed Description

As shown in fig. 1 to 3, a shielded cable has:

the cable comprises a first core wire 1, a first inner liner layer 2 tightly wrapping the first core wire 1 along the length direction, a first shielding layer 3 tightly covering the outer surface of the first inner liner layer 2 along the length direction, a second core wire 4 parallel to the first core wire 1 and outside the first shielding layer 3, a second inner liner layer 5 tightly wrapping the first shielding layer 3 and the second core wire 4 along the length direction, a second shielding layer 6 tightly covering the outer surface of the second inner liner layer 5 along the length direction, and an outer sheath 7 tightly wrapping the second shielding layer 6 along the length direction;

the first shielding layer 3 and the second shielding layer 6 adopt metal woven meshes, and the second core wire 4 is twisted on the first shielding layer 3 and forms electric contact with the first shielding layer 3; the first lining layer 2 and the second lining layer 5 are made of soft insulating materials with a damping effect, and the outer sheath 7 is made of insulating rubber or plastic materials.

The shielding cable can be used for alternating current transmission cables, two-core signal transmission cables and microwave coaxial cables, and the second core wire 4 is twisted on the first shielding layer 3 to form electric contact with the first shielding layer, so that characteristic impedance change is restrained, the problems of signal loss and waveform distortion caused by inductance and capacitance interference of the traditional cable are solved, and transmission loss is reduced.

In order to facilitate understanding of the implementation of the above-described shielded cable, the following description will be made of embodiments in which the shielded cable is used for an ac transmission cable, a two-core signal transmission cable, and a microwave coaxial cable, respectively.

[ EXAMPLES one ]

In a traditional alternating current transmission cable, three wires of N zero, L fire and E ground are stranded with the stranding ratio being 18 to 22 times, so that 3 inductors and 3 capacitors are generated, and the transmission loss is large.

As shown in fig. 1, when the shielded cable of the present invention is used for an ac transmission cable, the first core wire 1 adopts two wires twisted in a double spiral shape, and the two wires are respectively provided with an insulating layer 10; the two conductors of the first core wire 1 are set to have the same diameter and the stranding pitch thereof is 18 to 22 times the diameter of the wire; the second core wire 4 is a single conductor wire provided bare, and the second core wire 4 is stranded with the first shielding layer 3 at a stranding pitch including, but not limited to, 18 to 22 times its diameter.

The two wires of the first core 1 are respectively used as N zero and L fire two wires, and the second core 4 is used as E ground. Thus, in this embodiment, the nrot, L two wires generate only one inductance and one capacitance. And the interference of external electromagnetic radiation to the N zero line and the L fire line is isolated and shielded through the first lining layer 2 and the first shielding layer 3, the E ground is twisted on the first shielding layer 3 to be used as a ground drainage wire, the second lining layer 5 is adopted to be compressed and pressed to reduce vibration, and finally, the external electromagnetic radiation interference is isolated and shielded through the second shielding layer 6.

[ example two ]

Two heart yearns of two positive and negative signals of two traditional core signal transmission lines directly twist the back and cover inner liner, shielding layer, oversheath, the shortcoming lies in that the length and the material of shielding layer all are inconsistent with two heart yearns of positive and negative signal, have influenced transmission efficiency, the transmission of signal is serious loss.

As shown in fig. 2, when the shielded cable of the present invention is used for a two-core signal transmission line, the first core 1 is formed by two wires twisted in a double spiral shape, and the two wires are respectively provided with an insulating layer 10; the two conductors of the first core wire 1 are set to have the same diameter and the stranding pitch thereof is 18 to 22 times the diameter of the wire; the second core wire 4 is a single conductor with a bare wire, and the second core wire 4 is stranded with the first shielding layer 3 at a stranding pitch including, but not limited to, 18-22 times its diameter.

Wherein two wires of first core wire 1 are respectively as two heart yearns of positive and negative signal, through outer covering and through first inner liner 2, the interference of two heart yearns of positive and negative signal of external electromagnetic radiation of isolation shielding of first shielding layer 3, still through the earthing terminal of second heart yearn 4 sharing as positive and negative signal, and second heart yearn 4 transposition is as the ground wire drainage wire on first shielding layer 3, can not influence the characteristic impedance change, is favorable to improving transmission efficiency.

[ EXAMPLE III ]

In the traditional microwave coaxial cable, a shielding layer and an anode core wire exist, and negative feedback exists, so that anode transmission is influenced.

As shown in fig. 3, when the shielded cable of the present invention is used for a microwave coaxial cable, the first core wire 1 and the second core wire 4 are both made of a single conductor, and the first core wire 1 and the second core wire 4 form mutually independent and non-interfering electrical isolation through the first inner liner layer 2 and the first shielding layer 3; the second core wire 4 is stranded with the first shield layer 3 at a stranding pitch including, but not limited to, 18-22 times its diameter.

The first core wire 1 is used as a positive electrode signal circuit, the characteristic impedance is controlled by the first lining layer 2 and the first shielding layer 3, and the second core wire 4 is twisted on the first shielding layer 3 to serve as a negative electrode signal circuit, so that the material and the length of the positive electrode signal circuit and the negative electrode signal circuit tend to be consistent, the negative feedback of a transmission signal is inhibited, and the characteristic impedance is not influenced.

Various other modifications and alterations of the disclosed structure and principles may occur to those skilled in the art, and all such modifications and alterations are intended to be included within the scope of the present invention.

Claims

1. A shielded cable, characterized by comprising:

2. The shielded cable of claim 1, wherein the first core is formed by twisting two wires twisted in a double helix, the two wires having respective insulating layers; the second core wire adopts a single bare conductor.

3. A shielded electric cable according to claim 2, wherein the two conductors of the first core are arranged to have the same diameter and the stranding pitch is 18 to 22 times the diameter of the conductor.

4. The shielded cable of claim 1, wherein the first core wire and the second core wire are single bare wires, and the first core wire and the second core wire are electrically isolated from each other independently and without interference through the first lining layer and the first shielding layer.

5. The shielded cable as claimed in claim 1, 2, 3 or 4, wherein the second core wire is twisted with the first shield layer at a twisting pitch of 18 to 22 times its diameter.