JPH10149728A - Electric cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To heighten the manufacturing efficiency while effectively suppressing crosstalk occurrence. SOLUTION: A communication cable 10 is constituted of a plurality of unit cables 12a-12f, spacers 14 installed between neighboring unit cables 12a-12f, and an outer coating 18 which unitedly coats the unit cables 12a-12f and the spacers 14. The spacers 14 are made to be string-like material with round cross- section and made of a resin material having low dielectric constant. Six slots 16 spirally extended in the longitudinal direction of the spacers are formed on the surfaces of the spacers 14 in the circumferential direction at equal intervals and the unit cables 12a-12f are housed in respective slots 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric cable suitable for a communication cable, a control cable for instrumentation, and the like.

[0002]

2. Description of the Related Art Conventionally, for example, as shown in FIG. 4, a unit cable is constructed by integrally covering a plurality of lines 53 composed of a pair of electric wires with an outer cover 54, and furthermore, several unit cables 51a to 51a. 51f (six in the illustrated example)
A single communication cable is formed by integrally coating two communication cables.

In the communication cable 50 having such a large number of lines, it is necessary to prevent harmful coupling (crosstalk) between the electric wires due to the dielectric voltage.
At 1f, the occurrence of crosstalk in each line is suppressed by twisting the two core wires that are the basis of the line 53, respectively.

It is known that when a plurality of twisted wire pairs are bundled, the crosstalk between the wire pairs can be suppressed by setting the twist pitch of each wire pair to a different pitch. Then, by setting the twist pitch of the core wire of each line 53 in each of the unit cables 51a to 51f to a different pitch, crosstalk between the lines 53 is suppressed.
If the lines 53 in 1f are twisted together and the twisting pitch is set to a different pitch among the unit cables 51a to 51f, the unit cables 5
Crosstalk between 1a to 51f is suppressed.

[0005]

However, in the communication cable as described above, although crosstalk can be effectively suppressed, the twist pitch between lines must be set to a different value between each unit cable. The manufacturing efficiency is poor and the parts management is troublesome.

In recent years, there has been a tendency to include a very large number of lines in a single communication cable, which makes it difficult to produce the lines of each unit cable at different twist pitches, and furthermore, the twist pitch of the lines is low. There is a possibility that a situation in which crosstalk cannot be sufficiently suppressed by approximation may occur.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a communication cable capable of effectively increasing crosstalk while effectively suppressing crosstalk.

[0008]

In order to solve the above-mentioned problems, an electric cable according to the present invention comprises a plurality of unit cables comprising one or more electric wires and a low dielectric constant interposed between the unit cables. And a plurality of grooves each independently extending in the direction of the unit cable are provided in the spacer, and the unit cables are accommodated in the respective grooves.

According to this electric cable, since the unit cables are separated from each other by the spacer having a low dielectric constant, generation of a dielectric voltage between the unit cables can be suppressed. Therefore, it is not always necessary to set the twisting pitch of the wire between the unit cables to be different, and the structure of each unit cable can be shared.

Further, in the electric cable according to the present invention, each of the unit cables has a plurality of lines formed by twisting a pair of transmitting and receiving core wires, and each line is integrally twisted. In each of the unit cables, the twist pitch between the core wires of each line is set to a different pitch, and the twist pitch between the lines is set to the same pitch between the unit cables.

According to this electric cable, crosstalk between the lines can be effectively suppressed while a large number of lines are included in one cable, and a communication cable which is structurally advantageous can be constructed. it can.

Furthermore, in the electric cable according to claim 1 or 2, the spacer is formed to have a circular cross section, the grooves are provided at predetermined intervals in a circumferential direction, and each groove is spirally formed in the direction of the unit cable. It has been formed.

According to this electric cable, each unit cable is easily fixed to the spacer.

[0014]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a cross section of a communication cable as an example of an electric cable according to the present invention. As shown in this figure, the communication cable 10 includes a plurality of unit cables 12.
a to 12f and a spacer 14 interposed between the unit cables 12a to 12 and the unit cables 12a to 12f and the spacer 14
And are integrally covered by

As shown in FIG. 2, each of the unit cables 12a to 12f includes a plurality of lines 20a to 20d each composed of a pair of electric wires for transmission and reception. The cores constituting each of the lines 20a to 20d are twisted at a constant pitch, and the twisting pitch is different between the lines 20a to 20d. That is, since the cores constituting each of the lines 20a to 20d are twisted, the generation of the dielectric voltage between the transmission and reception cores is suppressed, whereby the crosstalk in each of the lines 20a to 20d is reduced. In addition, crosstalk between the lines 20a to 20d is suppressed by setting the pair twisting pitch different between the lines 20a to 20d.

In each of the unit cables 12a to 12f, the lines 20a to 20d are integrally twisted.

On the other hand, as shown in FIG. 1, the spacer 14 is a flexible cord-like member having a substantially circular cross section, and is made of a resin material having a low dielectric constant, for example, polyethylene or polypropylene (dielectric constant ε = 2.2 to 2.4), preferably from foamed polyethylene and foamed polypropylene.

On the surface of the spacer 14 are formed six slots 16 which are provided at regular intervals in the circumferential direction and extend spirally in the longitudinal direction of the spacer 14 as shown in FIG. As shown in FIG. 1, each of the unit cables 12a to 12
f is accommodated.

The communication cable 10 configured as described above
Then, as described above, the unit cables 12a to 12f are housed in the slots 16, and the unit cables 12a to 12f
f are arranged with the spacer 14 having a low dielectric constant therebetween, the unit cables 12a to 12f are hardly affected by the magnetic field of the adjacent unit cables 12a to 12f. Therefore, each unit cable 12
Even if the twist pitch of the lines 20a to 20d constituting the a to 12f is set to the same pitch, the unit cables 12a to 12d
Crosstalk between f can be effectively suppressed.

That is, according to the communication cable 10,
The structure of each unit cable 12a to 12f can be made common to improve the manufacturing efficiency.
There is an effect that crosstalk in 2a to 12f can be effectively suppressed.

According to the communication cable 10, since the unit cables 12a to 12f are housed in the slots 16 even if the communication cable 10 is stepped on, for example, the unit cables 12a to 12f There is also an advantage that the acting pressure can be reduced, thereby effectively preventing disconnection of the unit cables 12a to 12f and the like.

The communication cable 10 is an electric cable according to the present invention, and its specific configuration can be changed as appropriate without departing from the gist of the present invention.

For example, in the communication cable 10, the spacer 14 is made of polyethylene or polypropylene, but the spacer 14 may be made of any other material having a low dielectric constant. In this case, the dielectric constant [epsilon] is 3. although it depends on the type (use) of the electric wire accommodated in the slot 16.
It is desirable to form the spacer 14 using a material of 0 or less.

Incidentally, polyethylene or polypropylene is preferable in that it has a low dielectric constant as described above, but has relatively low flexibility. Therefore, when high flexibility is required, the spacer 14 may be made of, for example, a vinyl chloride resin or the like which is easy to obtain a soft product by blending a plasticizer. For example, if the spacers 14 are composed of a vinyl chloride resin mixture of calcium chloride and lead stearate in a vinyl chloride resin, the dielectric constant is relatively low (ε = about 3.0) and the flexibility is excellent. Spacer 14 can be obtained.

In the communication cable 10, the slots 16 are formed in the spacer 14 in a spiral shape. For example, as shown in FIG. 3 (b), the slots 16 are formed so as to extend straight and parallel to each other in the longitudinal direction. You may make it. According to such a spacer 14, FIG.
There is an advantage that manufacturing is easier than the spacer 14 shown in FIG. However, the spacer 14 shown in FIG.
In the communication cable 10 using the
Since 12f is wound around the spacer 14, there is an advantage that the fixing property is good and it is easy to handle in a production process or the like.

Although the communication cable 10 shown in FIG. 1 has a structure in which the unit cables 12a to 12f are bundled in a circle, the present invention can be applied to, for example, a flat cable structure. In this case, the spacer may be formed in a flat plate shape, and slots may be formed parallel to each other to accommodate the unit cable. According to the flat cable having such a structure, the occurrence of crosstalk in the unit cable can be effectively prevented, similarly to the communication cable 10.

[0028]

As described above, the electric cable of the present invention is provided with a plurality of unit cables and a spacer having a low dielectric constant, and the spacers independently extend in the direction of the unit cable. Grooves are formed to accommodate the unit cables in these grooves, respectively, so that the unit cables are less likely to be affected by the magnetic field. Therefore, the structure of each unit cable is shared and the production efficiency is improved. And crosstalk between the unit cables can be effectively suppressed.

In particular, each unit cable has a plurality of lines formed by twisting a pair of core wires for transmission and reception,
When the lines are twisted together, the twist pitch between the core wires of each line in each unit cable is set to a different pitch, and the twist pitch between the lines is the same between the unit cables. If the pitch is set, crosstalk between the lines can be effectively suppressed, and a communication cable that is structurally advantageous can be configured.

In such an electric cable,
If the spacers are formed in a circular cross section and the grooves are provided at predetermined intervals in the circumferential direction, and each groove is formed spirally in the direction of the unit cable, the fixability of each unit cable to the spacer is improved and the production process is improved. Etc. makes it easier to handle.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a communication cable (electric cable) according to the present invention.

FIG. 2 is a fragmentary sectional view showing a unit cable included in the communication cable.

FIG. 3A is a perspective view showing a spacer applied to the communication cable, and FIG. 3B is a perspective view showing a modified example of the spacer.

FIG. 4 is a sectional view showing an example of a conventional communication cable.

[Explanation of symbols]

 10 Communication cable 12a-12f Unit cable 14 Spacer 16 Slot 18 Outer skin 20a-20d Circuit

Claims (3)

[Claims] 1. A unit cable comprising a plurality of unit cables each comprising one or more electric wires, and a spacer having a low dielectric constant interposed between the unit cables. A plurality of grooves extending in a direction are provided, and each of the unit cables is housed in each groove. 2. Each of the unit cables has a plurality of lines formed by twisting a pair of core wires for transmission and reception,
Each line is twisted together,
2. The twist pitch between core wires of each line in each unit cable is set to a different pitch, and the twist pitch between lines is set to the same pitch between unit cables. Electric cable. 3. The spacer is formed to have a circular cross section,
3. The electric cable according to claim 1, wherein the grooves are provided at predetermined intervals in a circumferential direction, and each groove is spirally formed in a direction of the unit cable.