JP2008300249A - Paired strand communication cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To maintain satisfactory characteristics even if a frequency of a signal which is transmitted and received is not lower than 250 MHz, in a shielded type paired strand communication cable in which a metal-foil pasted plastic tape is disposed on the periphery of stranded conductor pairs. <P>SOLUTION: This paired strand communication cable is equipped with at least one or more conductor pairs 2 coated with an insulator 1, a metal-foil pasted plastic tape 3 disposed on the periphery side of the conductor pair 2 with its longitudinal direction paralleled with the axial direction of the cable (longitudinally paralleled), an adhesive layer 5 formed on the metal foil 4 of the metal-foil pasted plastic tape 3, and a sheath 6 which covers the outermost periphery and to the inner peripheral surface of which the metal foil 4 is bonded by the adhesive layer 5. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a shielded twisted communication cable used for high-speed signal transmission.

  FIG. 6 is a side view showing a configuration of a conventional shielded twisted communication cable.

  As shown in FIG. 6, a conventional shielded pair twisted communication cable twists a desired pair of conductors 102 covered with an insulator 101, and wraps an aluminum foil-laminated plastic tape 103 on the outer periphery of the pair of conductors 102. Further, the outer periphery of the aluminum foil-attached plastic tape 103 is covered with a sheath 104. A drain wire 105 is provided between the aluminum foil-laminated plastic tape 103 and the sheath 104.

  In Patent Document 1, a metal laminate tape is provided around a twisted pair wire, a drain wire is disposed on the outer periphery of the metal laminate tape, and a metal laminate tape is further provided on the outer periphery of the metal laminate tape and the drain wire. The provided twisted pair communication cable is described.

  Such a twisted communication cable can be used without problems if the frequency of signals to be transmitted and received is up to about 200 MHz.

  Further, in Patent Document 2, a plurality of conductive wire pairs covered with an insulator are arranged around a deformed interposed shaft, and the movement of each conductive wire pair is constrained by the deformed interposed shaft and covered with a sheath. A twisted pair communication cable is described.

Japanese Examined Patent Publication No. 6-22083 Japanese Patent Laid-Open No. 11-283449

  By the way, in the conventional shielded twisted communication cable as described above, when the frequency of a signal to be transmitted / received is 250 MHz or more, the following problems occur.

  That is, in the conventional shielded-twisted communication cable, in order to reduce crosstalk due to an increase in operating frequency, the performance is improved by improving the pitch of the conductor pairs and the pitch ratio of each conductor pair, etc. . However, in a shielded communication cable, since a plastic tape with a metal foil such as an aluminum foil is wound around it, reflection at a specific frequency occurs due to the periodicity of the winding pitch of the plastic tape. There was a problem.

  In such a communication cable, a configuration in which an aluminum foil-attached plastic tape is vertically attached, that is, the longitudinal direction is arranged along the axial direction is also conceivable. However, in this case, there has been a problem that the plastic tape with aluminum foil cannot be securely fixed, and the characteristics fluctuate when the communication cable is moved.

  Therefore, the present invention is proposed in view of the above-described circumstances, and provides a twisted communication cable that can maintain good characteristics even when the frequency of a signal to be transmitted and received is 250 MHz or higher. For the purpose.

  The twisted communication cable according to the present invention has any one of the following configurations.

[Configuration 1]
A shielded twisted pair communication cable used for signal transmission, and is arranged with at least one pair of conductor wires covered with an insulator and the longitudinal direction along the axial direction on the outer peripheral side of the conductor pair. Metal foil affixed plastic tape (attached vertically), an adhesive layer formed on the metal foil of the metal foil affixed plastic tape, and the metal foil was adhered to the inner peripheral surface by the adhesive layer covering the outermost periphery A sheath is provided.

[Configuration 2]
In the twisted communication cable having the configuration 1, the adhesive layer is intermittently formed on the metal foil of the metal foil-attached plastic tape, and the adhesive layer for the entire surface area of the metal foil is not formed. When the area ratio is an intermittent rate, the intermittent rate is 1% to 99%, and a drain wire is provided between the sheath and the metal foil-attached plastic tape. .

[Configuration 3]
In the twisted communication cable having the configuration 1 or the configuration 2, the metal foil of the metal foil-attached plastic tape is an aluminum foil.

[Configuration 4]
In the twisted pair communication cable having the configuration 1 or the configuration 2, the metal foil of the metal foil-attached plastic tape is a copper foil.

  In the twisted pair type communication cable according to the present invention having the configuration 1, the metal foil-attached plastic tape disposed on the outer peripheral side of the pair of conductors has the longitudinal direction along the axial direction (attached vertically) Since the adhesive layer formed on the foil is adhered to the inner peripheral surface of the sheath covering the outermost periphery, reflection may occur at a specific frequency according to the periodicity of the winding pitch of the metal tape with the metal foil. Since it is avoided and the plastic foil-laminated plastic tape is securely fixed, stable and good transmission characteristics and good characteristic impedance can be realized even when used at a high frequency of 250 MHz or higher.

  In the twisted communication cable according to the present invention having the configuration 2, the adhesive layer is intermittently formed on the metal foil of the metal foil-attached plastic tape, and between the sheath and the metal foil-attached plastic tape. Since the drain wire is provided, when the metal foil of the metal foil-attached plastic tape and the drain wire are electrically connected, a good characteristic impedance can be realized even when used at a high frequency of 250 MHz or higher.

  In the twisted pair communication cable according to the present invention having the configuration 3, since the metal foil of the metal foil-attached plastic tape is an aluminum foil, even when used at a high frequency of 250 MHz or higher, good transmission characteristics and good Characteristic impedance can be realized.

  In the twisted pair communication cable according to the present invention having the configuration 4, since the metal foil of the metal foil-attached plastic tape is a copper foil, even when used at a high frequency of 250 MHz or more, good transmission characteristics and good Characteristic impedance can be realized.

  That is, the present invention can provide a twisted communication cable that can maintain good characteristics even when the frequency of a signal to be transmitted and received is 250 MHz or more.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is a side view showing a configuration of a twisted communication cable according to the present invention.

  In the twisted pair communication cable according to the present invention, as shown in FIG. 1, a desired wire pair 2 covered with an insulator 1 is twisted. On the outer peripheral side of the conductive wire pair 2, a metal foil-attached plastic tape 3 is arranged with the longitudinal direction thereof being along the axial direction of the cable, that is, vertically attached. The metal foil in the metal foil-attached plastic tape 3 is, for example, an aluminum foil or a copper foil.

  The outermost periphery of the twisted communication cable is covered with a sheath 6. The sheath 6 is made of a polymer compound material having good wear resistance and heat resistance. The metal foil of the metal foil-attached plastic tape 3 is bonded to the inner peripheral surface of the sheath 6 by an adhesive layer formed on the metal foil of the metal foil-attached plastic tape 3. Further, a drain wire 7 is provided between the metal foil-attached plastic tape 3 and the sheath 6. The drain wire 7 is attached along the longitudinal direction of the cable in the axial direction of the cable, that is, vertically.

  FIG. 2 is a plan view showing the configuration of the metal foil-attached plastic tape of the twisted communication cable according to the present invention.

  In the metal foil-attached plastic tape 3, as shown in FIG. 2, the adhesive layer 5 is intermittently formed in a striped pattern on the metal foil 4. When the ratio of the area of the region where the adhesive layer 5 is not formed to the total surface area of the metal foil 4 is defined as an intermittent rate, the intermittent rate is 1% to 99%. The material forming the adhesive layer 5 can be appropriately selected according to the material forming the sheath 6.

  The metal foil 4 and the sheath 6 of the plastic foil-laminated plastic tape 3 can be sufficiently adhered by heat at the time of extrusion molding of the sheath 6 or heating by a hot jet or the like. By bonding the metal foil 4 and the sheath 6, the metal foil-attached plastic tape 3 is securely fixed in the sheath 6.

  And since the adhesive layer 5 is intermittently formed, the drain wire 7 is in electrical contact (conduction) with the metal foil 4 in the region where the adhesive layer 5 of the metal foil 4 is not formed. Yes. Accordingly, the drain wire 7 exhibits a sufficient shielding performance.

  FIG. 3 is a plan view showing another example of the configuration of the metal foil-attached plastic tape of the twisted communication cable according to the present invention.

  In the metal foil-attached plastic tape 3, the adhesive layer 5 may be intermittently formed in an island shape on the metal foil 4, as shown in FIG.

〔Example〕
As an example of the present invention, a twisted communication cable was prepared as follows. An annealed copper wire having an outer diameter of 0.65 mm was used as the conducting wire, polyethylene was used as the insulator, and the outer diameter of the insulator was 1.4 mm. Four pairs of conductor wires were twisted together. As the metal foil-attached plastic tape, an aluminum foil-attached plastic tape having a thickness of 65 μm obtained by attaching an aluminum foil having a thickness of 30 μm was used. The adhesive layer was an ionomer resin with a thickness of 30 μm, and the intermittent rate was about 50%. The aluminum foil is formed on the sheath side. The drain wire was a 20 / 0.18 mm tin-plated annealed copper wire, and the sheath was formed of non-halogen flame-retardant polyethylene having a thickness of 0.5 mm and an outer diameter of 10 mm.

  FIG. 4 is a graph showing characteristic impedance frequency characteristics of the twisted communication cable according to the present invention.

  FIG. 5 is a graph showing characteristic impedance frequency characteristics of a conventional twisted communication cable.

  The characteristic impedance frequency characteristic of the twisted pair communication cable according to the present invention is good as shown in FIG. 4 when the measurement length is 100 m and the measurement results of each pair of conductors are overlapped. That is, in the conventional twisted-type communication cable having a metal foil-attached plastic tape with a lap winding structure, as shown in FIG. 5, the characteristic impedance waveform is disturbed by reflection due to the tape winding periodicity. In the twisted communication cable according to the present invention, there is no such disturbance in the characteristic impedance waveform as shown in FIG.

[Other Examples]
The twisted communication cable according to the present invention is not limited to the materials in the above-described embodiments, and various materials can be used. For example, as for the conducting wire and the drain wire, not only an annealed copper wire but also a tin-plated annealed copper wire, a silver-plated annealed copper wire, and a copper alloy wire (including plating) can be considered. In addition, as a material forming the insulator and the sheath, not only polyethylene but also cross-linked polyethylene, polypropylene, fluororesin, and various other polymer materials can be used. Furthermore, even if the metal foil in the metal foil-attached plastic tape is a tin or silver plated copper foil in addition to the aluminum foil or the copper foil, the same effects as described above can be obtained. Moreover, you may insert an interposed axis between each conducting wire pair as needed.

It is a side view which shows the structure of the twisted communication cable which concerns on this invention. It is a top view which shows the structure of the metal foil sticking plastic tape of the twisted communication cable which concerns on this invention. It is a top view which shows the other example of a structure of the metal foil sticking plastic tape of the twisted communication cable which concerns on this invention. It is a graph which shows the characteristic impedance frequency characteristic of the twisted pair type communication cable which concerns on this invention. It is a graph which shows the characteristic impedance frequency characteristic of the conventional twisted communication cable. It is a side view which shows the structure of the conventional shielding pair twist type | mold communication cable.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Insulator 2 Conductor pair 3 Metal foil sticking plastic tape 4 Metal foil 5 Adhesive layer 6 Sheath 7 Drain wire

Claims (4)

A shielded twisted communication cable used for signal transmission,
At least one wire pair covered with an insulator;
On the outer peripheral side of the conductive wire pair, a metal foil-attached plastic tape disposed along the axial direction in the longitudinal direction;
An adhesive layer formed on the metal foil of the metal foil-attached plastic tape;
A twisted communication cable comprising: a sheath covering an outermost periphery and having the metal foil adhered to an inner peripheral surface by the adhesive layer. The adhesive layer is intermittently formed on the metal foil of the metal foil-attached plastic tape, and the ratio of the area of the region where the adhesive layer is not formed to the total surface area of the metal foil is an intermittent rate. The intermittent rate is 1% to 99%,
The twisted communication cable according to claim 1, wherein a drain wire is provided between the sheath and the metal foil-attached plastic tape. The twisted communication cable according to claim 1 or 2, wherein the metal foil of the metal foil-attached plastic tape is an aluminum foil. The twisted communication cable according to claim 1 or 2, wherein the metal foil of the metal foil-attached plastic tape is a copper foil.

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