JP5366430B2 - LAN cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a LAN cable 10 comprising at least two pairs of twisted wires 20 each formed of twisting two insulating wires 22 each having an insulatingly covered center conductor 21, and a coating 30 covering the outer peripheries of the pairs of twisted wires 20 in a lump, having good electric properties while achieving more space saving than that in the prior art. <P>SOLUTION: The contraction percentage of the coating 30 is &le;2% under predetermined conditions, an outer diameter L of the center conductor 21 of the insulating wire 22 is &le;0.4 mm, and an outer diameter M of the cable is &le;4 mm. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention includes a LAN cable, in particular, at least two pairs of twisted wires formed by twisting two insulated wires having a central conductor insulated, and a jacket whose outer periphery is collectively covered with the twisted wires. It relates to a LAN cable.

With the practical application of LAN, development of a communication cable for signal transmission suitable for high-speed communication is strongly desired. As the transmission rate increases, it is necessary to improve the crosstalk attenuation characteristics of the communication cable. As a communication cable with improved crosstalk attenuation characteristics, for example, as disclosed in Patent Document 1, a cross-shaped interposition is used. Communication cable is known. In this known communication cable, twisted wires having different twisting pitches are arranged in four storage areas whose cross sections are defined by a cross-shaped interposition, thereby improving crosstalk attenuation characteristics between adjacent twisted wires. It is done.
Japanese Patent Laid-Open No. 11-53958

  In addition to improvements in electrical characteristics such as crosstalk characteristics, high-density mounting type switching hubs and patch panels are used in current data centers and offices. Since a large number of the cables are densely arranged in the space provided, it has been desired to provide a communication cable that can reduce the occupied space.

  An object of the present invention is to provide a LAN cable that has good electrical characteristics and can save space compared to the conventional one.

  As a result of studies to solve the above-mentioned problems, the present inventors have found that at least two pairs of twisted wires formed by twisting two insulated wires having a central conductor insulated, and the outer periphery of the twisted wires. If the outer diameter of the central conductor of the insulated wire is 0.4 mm or less and the outer diameter of the cable is 4 mm or less, the cable is wired to the specified piping. As a result, it has been found that the number of wires more than twice that of the conventional one can be wired, and the allowable bending radius of the cable can be reduced, resulting in a significant reduction in occupied space.

However, if the outer diameter of the central conductor and the cable is simply reduced, the jacket of the thinned LAN cable shrinks due to heat or aging. Due to the shrinkage difference, stress in the cable length direction is applied to the twisted pair. Due to this stress, distortion occurs in the twisted pair wire, and the internal structure of the twisted pair wire is not uniform. As a result, signal reflection occurs and electrical characteristics such as return loss are greatly deteriorated. It was difficult to produce a product.
Therefore, as a result of further earnest research, the outer diameter of the central conductor and the cable is reduced by optimizing the outer sheath of the LAN cable so that the shrinkage rate under a predetermined condition is 2% or less. It has been found that a LAN cable having good electrical characteristics and space saving compared to the conventional one can be provided because deterioration of electrical characteristics due to the reduction can be reduced.

In order to achieve the above object, the gist of the present invention is as follows.
(1) Provided with at least two pairs of twisted wires formed by twisting two insulated wires with insulation coating on the center conductor, and a jacket with insulation covering the outer periphery of the pair of twisted wires together and having a total length of 50 m or less A LAN cable used between permanent links,
The shrinkage when the jacket is used in an environment of 100 ° C. for 120 hours is 2% or less, the outer diameter of the central conductor of the insulated wire is 0.3 mm or less, and the cable outer diameter is 4 mm or less. A LAN cable characterized in that the twist pitch of the stranded wire is in the range of 6 to 10 mm and has electrical characteristics satisfying the CAT5e standard.

(2) The LAN cable according to (1) above, wherein the material of the jacket is polyvinyl chloride, flame retardant polyethylene or fluororesin, and its volatilization loss is 3% or less.

(3) the jacket material, seven of the LAN cable, after the length was cut so as to 3m, from a bundled state at a pressure of 300Pa range of 1m from the center of each cable, the most central The LAN cable according to claim 1 or 2, wherein a tensile resistance required for pulling out one positioned cable is 10 N or less.

  According to the present invention, it is possible to provide a LAN cable that has good electrical characteristics and can save space compared to the conventional one.

  Hereinafter, the configuration of the present invention and the reasons for limitation will be described with reference to the drawings.

FIGS. 1A and 1B are enlarged schematic views showing the cross section of the LAN cable of the present invention for easy explanation.
As shown in FIG. 1 (a), the LAN cable 10 according to the present invention includes at least two pairs of twisted wires formed by twisting two insulated wires 22 in which a central conductor 21 is insulated, and the twisted wires 20. And an outer cover 30 in which the outer periphery is collectively covered with an insulating coating.

  As shown in FIG. 1A, the LAN cable 10 of the present invention has a shrinkage rate of 2% or less under a predetermined condition of the jacket 30 and an outer diameter L of the central conductor 21 of the insulated wire 22 is 0.4. It is characterized in that it is mm or less and the cable outer diameter M is 4 mm or less.

By reducing the center outer diameter L of the insulated wire to 0.4 mm or less and the cable outer diameter M to 4 mm or less, the cross-sectional area can be reduced to about half that of a conventional LAN cable. This is because the bending radius of the cable 10 can be reduced by reducing the cross-sectional area, and as a result, even when the cable is folded and stored, a great effect of space saving can be achieved. .
Furthermore, by optimizing the jacket 30 so that the shrinkage rate under a predetermined condition is 2% or less, the outer diameters of the central conductor 21 and the cable 10 are reduced, so This is because it becomes possible to reduce the deterioration of the electrical characteristics due to the difference in shrinkage rate.

  Here, the shrinkage rate under the predetermined condition refers to the rate (%) of shrinkage of the jacket 30 and the twisted wire 20 caused by heat or aging of the cable jacket 30, and the conditions in the present invention. Means the shrinkage rate (%) of each of the jacket 30 and the twisted pair wire 20 when used in an environment of 100 ° C. or higher for 120 hours or longer.

In addition, the twisted pair wire 20 of the present invention is formed by twisting two insulated electric wires 22 in which a central conductor 21 is insulated and coated, as shown in FIG.
As described above, as long as the outer diameter of the center conductor 21 is 0.4 mm or less, a material used for a normal LAN cable, for example, soft copper, hard copper, aluminum, or the like may be used, and there is no particular limitation. Moreover, what is necessary is just to use what is normally used also about the insulating film 21a which coat | covers the said center conductor 21. FIG.

Here, FIG. 2 is an enlarged view of the twisted pair wire 20 from the side, but the twist pitch P of the twisted pair wire 20 is in the range of 6 to 10 mm . This is because when the twist pitch P is less than 6 mm, the number of man-hours to be twisted is increased, and when it exceeds 10 mm, the structure is easily broken and the impedance becomes unstable.

  Furthermore, the twist pitch P of the twisted pair wire 20 is preferably different for each twisted pair wire 20 constituting the cable 10. When the twist pitch P is set to the same value for all the twisted wires 20 (four twisted wires 20 in FIG. 1 (a)), the respective electrical signals interfere with each other. This is because characteristics such as level far end crosstalk deteriorate.

  The jacket 30 of the present invention is a member that covers the outer periphery of the twisted wire 20 as shown in FIG. The configuration is not particularly limited as long as the outer diameter is 4 mm or less and the contraction rate is 2% as described above, but the predetermined contraction rate can be realized. As a possible material, it is preferable to use polyvinyl chloride, flame-retardant polyethylene or fluororesin having a predetermined volatilization loss of 3% or less.

  Here, the volatilization loss in the present invention refers to the ratio (%) of the mass reduced when the material is held at 100 ° C. for 120 hours under an environmental test. The reason why the volatilization loss is 3% or less is that if the volatilization loss is 3% or less, the shrinkage rate of the jacket 30 can be effectively suppressed to 2% or less.

  In addition, it is preferable that the outer cover 30 has a tensile resistance of 10 N or less when the outer cover material is pulled out from a state where a plurality of the LAN cables are bundled. In the LAN cable 10 of the present invention, the twisted pair wire 20 is thinner and the jacket 30 is thinner than the conventional cable. For this reason, since the mechanical strength is lower than that of a conventional LAN cable, a strong force is exerted on the cable 10 when a single cable 10 is pulled out from a state in which many cables are laid together. When added, the twisted wire 20 may be stretched or broken, resulting in an adverse effect on electrical characteristics. Therefore, by reducing the frictional force of the jacket 30, the friction between the cables 10 is reduced, the deterioration of the electrical characteristics due to the elongation and breakage is prevented, and the above problem is solved. The state in which a plurality of the LAN cables are bundled is not particularly limited. For example, a state in which seven LAN cables are bundled at a pressure of 300 Pa in a length range of 1 m, and one of them is pulled out. The tensile resistance required sometimes may be 10N or less.

  Further, the LAN cable 10 of the present invention can further include a drain wire 31 inside the jacket 30 as shown in FIG.

  Furthermore, the LAN cable 10 of the present invention can also include a cross interposition 40 inside as shown in FIG. This cross interposition 40 is effective in that the crosstalk attenuation characteristics between the adjacent twisted pair wires 20 can be improved.

FIG. 3 shows one embodiment of the channel using the LAN cable 10 of the present invention. The LAN cable 10 of the present invention is used between the permanent links 100 having a total length X of 50 m or less . Here, the permanent link 100 is one in which a patch panel 50 and an outlet 60 are provided at both ends of the LAN cable 10 as shown in FIG. If the length X of the permanent link 100 is set to 50 m or less, the deterioration of the electric characteristics will not be noticeable. Therefore, the electric characteristics equivalent to those when using the conventional LAN cable are provided, and the space can be saved. This is effective in that it is possible to provide the indicated permanent link.

  The above description is merely an example of the embodiment of the present invention, and various modifications can be made within the scope of the claims.

Example 1
As Example 1, as shown in FIG. 1 (a), at least two pairs of twisted wires formed by twisting two insulated wires 22 in which a central conductor 21 is insulated and an outer periphery of the twisted wires 20 are arranged. A jacket 30 made of a low-friction material that is collectively covered with an insulation coating, the shrinkage rate of the jacket 30 is 2%, the outer diameter L of the central conductor 21 of the front insulated wire 22 is 0.3 mm, and the outer diameter of the cable A LAN cable having M of 3.7 mm was produced as a sample.

(Comparative Example 1)
As Comparative Example 1, a LAN cable having the same configuration as Example 1 was prepared as a sample except that the shrinkage rate was 5%.

(Comparative Example 2)
As Comparative Example 2, a LAN cable having the same configuration as Example 1 was prepared as a sample, except that the jacket was not made of a low friction material.

(Comparative Example 3)
As Comparative Example 3, a LAN cable having the same configuration as that of Example 1 was prepared as a sample except that the outer diameter L of the central conductor 21 of the pre-insulated electric wire 22 was 0.5 mm and the outer diameter M of the cable was 5.3 mm. .

(Evaluation method)
The LAN cable obtained as described above was evaluated according to the following evaluation method.

(1) Electrical characteristics with respect to standard (CAT5e) For the sample produced in Example 1, a channel model (channel length Y: 60 m, permanent link length X: 50 m) as shown in FIG. 3 was produced.
The electrical characteristics (a. Insertion loss (10 MHz), b. Insertion loss (100 MHz), c. Near-end crosstalk attenuation, d. Power sum near-end crosstalk attenuation, e. , F. Power sum equal level far-end crosstalk, g. Attenuation to crosstalk ratio, h. Attenuation to power sum crosstalk ratio, i. Return loss, j. Propagation delay time, k. Delay time difference). The measured electrical property values were evaluated by calculating a margin with respect to the CAT5e standard. The calculated results are shown in Table 1.

(2) Return loss characteristics For the samples of Example 1 and Comparative Example 1, using a vector network analyzer, the magnitude (reflection loss) (dB) of the signal that is returned after the input signal is reflected is measured. Went. The measurement results are shown in FIGS. 4 (a) and 4 (b), FIG. 4 (a) for Example 1, and FIG. 4 (b) for Comparative Example 1.
For this evaluation, four pairs of cables were prepared as sample LAN cables of Example 1 and Comparative Example 1, and each pair was connected to the 12-pin, 36-pin, 45-pin, and 78-pin connectors. .

(3) Resistance by pulling Prepare 7 samples each of Example 1 and Comparative Example 2 and cut them to a length of 3 m, then press the pressure of about 300 Pa in the range of 1 m from the center of each cable. So I bundled the seven cables together. Thereafter, the force (N) required for pulling out the cable located at the center of the seven bundled cables was measured. The measurement results are shown in Table 2.

(4) Number of filled pipes For the samples of Example 1 and Comparative Example 3, the maximum number of pipes that could be filled into a pipe with an inner diameter of 20 mm and a pipe with an inner diameter of 30 mm was measured. Table 3 shows the measurement results.

From the results shown in Table 1, the channel using the sample of Example 1 has cleared the standard (CAT5e) in all items (a to k), so the present invention is used for use at a short distance (within 50 m). It turned out that there was no problem in using the cable.
4A and 4B, the sample of Example 1 has a large return loss (dB) at any frequency compared to the sample of Comparative Example 1, and the thermal contraction of the jacket. It was found that the effect of reducing the rate was exhibited.
Furthermore, from the results of Table 2, the sample of Example 1 has a smaller force (N) required for pulling out than the sample of Comparative Example 2, and can suppress the cable elongation and the jacket tearing that occur during pulling. I understood.
Furthermore, from the results in Table 3, the sample of Example 1 can be filled with more cables (about 2.5 to 2.7 times) than the sample of Comparative Example 3, and space saving can be achieved here. I understood.

  According to the present invention, it is possible to provide a LAN cable that has good electrical characteristics and can save space compared to the conventional one.

It is sectional drawing which expanded and showed typically the LAN cable of this invention. It is the figure which expanded the twisted pair wire used for the LAN cable of this invention, and was seen from the side. It is the figure which showed typically the state seen from the side about the channel structure using the LAN cable of this invention. It is the graph which showed the return loss (dB) with respect to the frequency at the time of using the LAN cable (12 pin, 36 pin, 45 pin, 78 pin) of Example 1 and Comparative Example 1, Comprising: (a) Examples 1 and (b) show the results of Comparative Example 1.

Explanation of symbols

10 LAN cable 20 Twisted wire 21 Center conductor 22 Insulated electric wire 30 Outer sheath 31 Drain wire 40 Cross interposition

Claims (3)

Between permanent links with a total length of 50 m or less, comprising at least two pairs of twisted wires formed by twisting two insulated wires with insulation coating on the center conductor and a jacket with the outer periphery of the twisted wires collectively covered with insulation coating LAN cable used in
The shrinkage when the jacket is used in an environment of 100 ° C. for 120 hours is 2% or less, the outer diameter of the central conductor of the insulated wire is 0.3 mm or less, and the cable outer diameter is 4 mm or less. A LAN cable characterized in that the twist pitch of the stranded wire is in the range of 6 to 10 mm and has electrical characteristics satisfying the CAT5e standard.   The LAN cable according to claim 1, wherein the material of the jacket is polyvinyl chloride, flame retardant polyethylene, or fluororesin, and its volatilization loss is 3% or less. The envelope material, seven of the LAN cable, positioned after the length was cut so as to 3m, from a bundled state at a pressure of 300Pa range of 1m from the center of each cable, the most central cable The LAN cable according to claim 1 or 2, wherein a tensile resistance required for pulling out one of said cables is 10 N or less.

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