JPH03216914A - Manufacture of low crosstalk cable and braiding machine used therefor - Google Patents

Abstract

PURPOSE:To provide excellent crosstalk preventing characteristic by forming a cable core independently arranging inner sheath layers on respective twisted pair insulated wires, separating and covering respective inner sheath layers with inner shield layers, and further arranging an outer shield layer and an outer sheath layer over them. CONSTITUTION:An inner sheath layer 17 made of PVC(polyvinyl chloride) is provided over the twisted pair insulated wires 10, 11 on one side and an inner sheath layer 18 made of the same material is provided over the other pair of twisted insulated core wires 12, 13. The inner sheath layers 17, 18 are covered and separated independently from each other wire an inner shield tape 19 placed in an S shape along the length of the sheaths. On the inner shield tape 19 is provided a braided shield layer 20 as an external shield layer. Over the braided shield layer 20 is provided with an external sheath layer 21 made of PVC. As a result, the twisted pair insulated wires 10, 11 and 12, 13 are shielded from each other with the inner shield tape 19 so that the characteristic against crosstalk between those wires is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a low crosstalk cable with improved crosstalk characteristics between twisted pairs of insulated core wires, and a braiding machine used for manufacturing the same.

(Prior art) When using signal cables with twisted insulated core wires in integrated services digital networks (ISDN), etc., when the transmission speed of digital signals increases, the crosstalk characteristics between the twisted insulated core wires decreases. do. Therefore, there is a problem in that near-end crosstalk occurs between the twisted insulated core wire pairs, and the code error rate increases.

Now, FIG. 2 is a cross-sectional view of a conventional round signal cable having twisted pair insulated core wires. This signal cable includes two sets of twisted pair insulated core wires 1.2 and 3.4.

These insulated core wires 1 to 4 are conductors 1a, 2a, . . . made of annealed copper wire, respectively. 3a, 4a and a polyethylene insulating layer 1b coated thereon. 2b. It is composed of 3b and 4b. The pair of twisted insulated core wires 1.2 and the other twisted pair of insulated core wires 3.4 are twisted at different pitches and then further twisted together, and a polyvinyl chloride sheath layer 5 is provided thereon. ing. Further provided on this sheath layer 5 are a tape shielding layer 6 made of a plastic tape laminated with aluminum, a braided shielding layer 7 made of tin-plated annealed copper wire, and an outer sheath layer 8 in this order. In this cable, low-frequency external noise is shielded by the braided shielding layer 7, and high-frequency external noise is shielded by the tape shielding layer 6, so it has the advantage of being able to prevent external noise from entering and radiating over a wide band. be.

(Problems to be Solved by the Invention) However, simply by further twisting the twisted pair of insulated core wires 1.2 and the other pair of insulated core wires 3.4 to each other in this manner, these insulated core wires 1. Since the distance (spacing) between 2 and 3.4 is small, there is a drawback that near-end crosstalk occurs even when a digital signal is transmitted at, for example, several hundred KBPS.

The present invention was made to solve these problems, and an object of the present invention is to provide a low crosstalk cable with excellent crosstalk characteristics and a braiding machine used for manufacturing the same.

(Means for Solving the Problems) The low crosstalk cable of the present invention has inner sheath layers independently provided on each twisted pair of insulated core wires to form a cable core, and each inner sheath layer is formed into an inner shielding layer. It is characterized in that it is separated and covered, and further provided with an outer shielding layer and an outer sheath layer thereon.

The braiding machine of the present invention also includes a tape supply mechanism that supplies a shielding tape as an internal shielding layer, a cable core guide mechanism that guides a pair of cable cores to travel along with the shielding tape on both sides thereof, and A tape forming device vertically attaches a shielding tape in an S-shape on a pair of cable cores, and a braided wire is provided as an external shielding layer on the vertically attached shielding tape by a braiding machine body. shall be.

(Function) In the low crosstalk cable of the present invention, an inner sheath layer is provided on each twisted insulated core wire, and the distance between each twisted insulated core wire is set large by the thickness of the inner sheath layer, and each inner sheath layer is internally shielded. Since the layers are separated and covered, the crosstalk characteristics of the cable are improved. Therefore, even if digital signals are transmitted at high speed through each twisted pair of insulated core wires, near-end crosstalk can be reliably prevented from occurring. The internal shielding layer and the external shielding layer can also prevent external noise from entering and radiating.

Further, in the braiding machine of the present invention, the tape supply mechanism supplies the shielding tape toward the tape forming device. On the other hand, the cable core guide mechanism guides the pair of cable cores to both sides of the shielding tape, and causes them to travel together with the shielding tape toward the tape forming device. The tape forming device bends the shielding tape into an S-shape and attaches it vertically onto a pair of cable cores. Then, the braiding machine main body continuously provides an external shielding layer made of a braided wire on the vertically attached shielding tape.

Therefore, the inner shielding layer and the outer shielding layer of the low crosstalk cable can be provided in one step. Therefore, a low crosstalk cable can be manufactured at low cost, and the installation space for manufacturing equipment can be reduced.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view of a low crosstalk cable according to the present invention.

This low crosstalk cable has twisted pair insulated core wires 10, 11 and 1
2.13. These insulated core wires 10 to 13
are conductors 10a, l made of annealed copper wire with a diameter of 0.65 mm.
la, 12a. 13a and 0. The polyethylene insulating layer 10b, llb. is coated with a wall thickness of 3 mm and an outer diameter of 1.25 mm. 12b and 13b. An inner sheath layer 17 made of polyvinyl chloride is provided on one of the twisted insulated core wire pairs 10.11, and an inner sheath layer 18 made of the same material is provided on the other twisted insulated core wire 12.13. ing. These inner sheath layers 17
．． 18 is 0. It has a wall thickness of 5 mm and an outer diameter of 4 mm, and forms a cable core together with the insulated core wire.

These inner sheath layers 17 and 18 are separated and covered independently by an internal shielding tape 19 that is vertically attached in an S-shape. This internal shielding table 19 has a structure in which aluminum is laminated on both sides of a plastic table, and 0. 3 with a thickness of 055mm
It is formed with a width of 0 mm. A braided shield layer 20 is provided on the inner shielding table 19 as an outer shielding layer. This braided shield layer 20 is formed by braiding tin-plated annealed copper wires having a diameter of 0.1 mm. An outer sheath layer 21 of polyvinyl chloride is provided on the braided shield layer 20. This outer sheath layer 21 is 0
．． It has a wall thickness of 5 mm, which makes the width 6. OxlO
．． A low crosstalk cable of the present invention of Omm is obtained.

In this way, when each inner sheath layer 17, 18 is separated and covered by the inner shielding table l9, the twisted pair insulated core wire 10.1
1 and 12.13 are mutually shielded by the internal shielding table 19. In addition, each insulated core wire 10, 11 and 1
2.13 are covered with inner sheath layers 17 and 18, respectively, so the distance between them is increased by the thickness of these sheath layers 17.18. Therefore, the crosstalk characteristics between the twisted insulated core wire pairs 10.11 and 12.13 are improved, so that near-end crosstalk does not occur between these insulated core wires even when digital signals are transmitted at high speed.

Further, the internal shielding table 19 shields high-frequency external noise, and the braided shield layer 20 shields low-frequency external noise, so that it is possible to prevent external noise from entering and radiating over a wide band.

By the way, when the near-end crosstalk attenuation of the low crosstalk cable of the present invention having each of the above-mentioned dimensional configurations was measured while changing the frequency, it was approximately 90 dB in the range from 100 κHz to 10 Mt{z, and 70 dB at 30 MHz.

<Comparative Example> A conventional round signal cable shown in FIG. 2 was prototyped, and its near-end crosstalk attenuation was measured. ．． That is, each insulated core wire 1 to 4
is a conductor made of annealed copper wire with a diameter of 0.65 mm, and a conductor of 0.65 mm in diameter on top of the annealed copper wire. It consists of a polyethylene insulation layer coated with a wall thickness of 3 mm. Moreover, the polyvinyl chloride sheath layer 5 is 0. It is formed with a wall thickness of 7 mm and an outer diameter of 6.2 mm. The tape shielding layer 6 on this sheath layer 5 is made of a plastic tape laminated with aluminum on one side.
It is formed to have a thickness of 0.4 mm and a width of 25 mm. Furthermore, the braided shield layer 7 is formed by braiding tin-plated annealed copper wire with a diameter of 0.1 mm, and the outer sheath layer 8 made of polyvinyl chloride is formed to have a thickness of 0.7 mm.

In a conventional round signal cable with such a configuration, its crosstalk attenuation is 70 dB in IOOK}Iz, 300K}l
60dB at z, 50dB at I MHz, 10MHz
It was 40dB at z and 30dB at 30Mllz.

From the above, it can be seen that the low crosstalk cable of the present invention has improved near-end crosstalk attenuation by 20 to 50 dB over the conventional signal cable, and has significantly improved crosstalk characteristics particularly in the high frequency band.

In addition, in the low crosstalk cable shown in Fig. 1, the inner sheath layer 1
Of course, a shielding tape may be applied vertically or wrapped around the inner shielding layers 7 and 18, respectively.

Next, FIG. 3 is an overall configuration diagram of a braiding machine according to the present invention. This braiding machine includes a braiding machine main body 30. This braiding machine main body 30 has a well-known configuration, and includes a revolving rotary body 32 rotatably attached to a base 3l, and a revolving rotary body 32 rotatably attached to a base 3l.
It has a plurality of supply bobbins 33 which are arranged concentrically on the front surface of 2 and are detachably and rotatably attached, and each supply bobbin 33 is wound with a tin-plated annealed copper wire 20a.

These tin-plated annealed copper wires 20a are respectively introduced into guide tubes 34 protruding from the front surface of the revolving rotary body 32, and are drawn out forward by these guide tubes 34. Each of the tin-plated annealed copper wires 20a drawn out is passed through a batten 35.

A tape supply mechanism 36 is provided within the base 3l.

This tape supply mechanism 36 is shown in FIG. 4(A). As shown in (B), the frame 37 fixed to the base 3l, the mounting plate 38 fixed to the frame 37, the reel 39 rotatably mounted to the mounting plate 38, and the mounting An outlet roll 4o attached to the protrusion at the tip of the plate 38, and a pair of torsion rollers 41 disposed in front of the outlet roll 40.
It consists of The torsion rollers 41, 41 are fixed to the support rod 42 with their rotational axes slightly shifted in the radial direction. In this tape supply mechanism 36, a tape pad 19a consisting of a shielding table 19 is attached to the knoll 39. This shielding table 19 is unwound from the reel 39, led out at the outlet port 40, and is pressed against and supplied to the twisting rollers 41, 41. Therefore, the shielding table 19 is twisted by the twisting rollers 41, 41 after being let out from the reel 39.

At the center of the base 31, as shown in FIG. 3, a cable core guide mechanism 43 is arranged. As shown in FIG. 5, this cable core guide mechanism 43 includes a pair of guide rollers 44.
, 45. These guide rollers 44 and 45 are rotatably attached to the support 46 at a constant interval and slightly offset in the width direction of the shielding table 19. Each support 46 is fixed to a support rod 47, and the support rod 47
is fixed to the base 3l. In this cable core guide mechanism 43, a pair of guide rollers 44, 45 guide the fed cable cores 48, 49 in substantially orthogonal directions, respectively, so that the cable cores 48, 49 are guided on both sides of the tape 19 along the feeding direction of the shielding table l9. Run each. Incidentally, the cable cores 48 and 49 are made of the above-mentioned pair of insulated core wires 10, 11 and 1.
2.13 and the inner sheath layer 17 provided thereon.
18, respectively.

As shown in FIG. 3, a tape forming device 50 is disposed between the revolving body 32 and the batten 35. As shown in FIG. This tape forming device 50 is shown in FIG. 6(A). (B
), the forming body 51 has an introduction part 51A with an upper opening into which the shielding table 19 and the cable core 48, 49 are introduced, and an introduction part 51A with an approximately elliptical cross section gradually tapering toward the tip. It consists of a tape bent portion 51B that is bent so as to The forming main body 5l is supported on a support stand 53 by a column 52. A forming die 5 is placed on the tip side of the forming body 5l.
4 is arranged, and this molding die 54 is also supported on the support stand 53. A shielding table 19 is placed in the center of the molding die 54.
An oval die hole 54 is used to completely form the S-shape.
A is provided.

Next, the operation of the braiding machine of the present invention will be explained.

The shielding tape 19 supplied by the tape supplying mechanism 36 is unwound from the reel 39 while being given pack tension, is twisted by twisting rollers 41 and 41, is introduced between guide rollers 44 and 45, and is further attached to the revolving rotating body. The forming body 5l is passed through the center through hole (not shown) of 32.
is supplied to

On the other hand, the cable cores 48, 49 are guided by the guide rollers 44, 45.
It travels along with the shielding tape 19 on both sides of the shielding tape 19, and similarly passes through the central through hole of the revolving rotary body 32 and is guided to the forming body 5l. Therefore, the sixth
As shown in the figure, the shielding table 19 and cable cores 48, 49 are introduced into the forming main body 5l with a cable core 49 located on the upper surface of the shielding table 19 and another cable core 48 located on the lower surface thereof. Ru.

When the cable cores 48, 49 and the shielding table 19 are pulled in such a state, one end of the shielding table 19 is bent upward by the tape bending part 51B of the forming body 51, and the other end is bent downward, and the cable It is attached vertically on the cores 48 and 49 in an S-shape. and,
Since the shielding table l9 that has passed through the forming main body 5l is passed through the die hole 54a of the forming die 54,
It is completely formed into an S-shape and is placed vertically on the cable cores 48, 49.

The cable cores 48, 49 and the vertically supporting shielding table 19 that have passed through the forming die 54 are further passed through the center of the batten 35, but in this case, the revolving rotary body 32 is rotated by a drive mechanism (not shown). Therefore, each supply bobbin 33 feeds out the tin-plated annealed copper wire 20a while the tape forming device 5
It revolves around 0. Therefore, since the braided shield layer 20 is formed on the vertically attached shielding tape 19, the shielding tape 19 can be longitudinally attached on the cable cores 48, 49 and the braided shield layer 20 can be provided in one step.

(Effects of the Invention) As explained above, according to the present invention, an inner sheath layer is independently provided on each twisted insulated core wire pair, the interval between each twisted insulated core wire pair is set large, and each inner sheath layer Since the layers are separated and covered by internal shielding layers, the crosstalk characteristics of the cable can be improved. Therefore, even when transmitting digital signals at high speed, near-end crosstalk can be reliably prevented, and the internal shielding layer and the external shielding layer can also reliably prevent external noise from entering and radiating. Therefore, it is possible to provide a low crosstalk cable that has excellent noise resistance characteristics and almost never generates near-end crosstalk.

Further, according to the braiding machine of the present invention, the tape supply mechanism supplies the shielding tape to the tape forming device, and
The pair of cable cores are positioned on both sides of the shielding tape by the cable core guide mechanism and run to the tape forming device, so the shielding tape is attached vertically in an S-shape on the pair of cable cores by the tape forming device. The inner shielding layer can be provided simultaneously with an outer shielding layer of braided wire thereon. Therefore, since the inner and outer shielding layers can be provided in one step, the low crosstalk cable of the present invention can be manufactured at low cost, and the installation space of the manufacturing equipment can be reduced by one step.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a low crosstalk cable according to the present invention, FIG. 2 is a cross-sectional view of a conventional signal cable, FIG. 3 is an overall configuration diagram of a braiding machine according to the present invention, and FIG. 4 (A). (B) is a plan view and a front view showing the tape supply mechanism of the braiding machine, and
The figure is a front view of the cable core guide mechanism of the same braiding machine, and FIGS. 6(A) and 6(B) are a plan view and a front view, respectively, showing the tape forming device of the same braiding machine. 10, If, 12. 13 --- one insulated core wire, 17
．． 18--One inner sheath layer, 19--One inner shielding tape, 20--
- one braided shielding layer, 21. --1-1-1 outer sheath layer, 30--1 braiding machine main body, 36--1-tape supply mechanism, 43--1-cable core guide mechanism, 44. 45
-1-1 guide roller, 48.49--1 cable core, 50-------table forming device, 5 1
−−−−−−−Table forming body. Fig. 4 10 11, 12.13--Insulated core wire 17.18--
----1 inner sheath layer 1 9----------1 internal shielding tape 2 0--1-1 braided shield layer 2 1-- Outer sheath layer 30---
-------1 item
5-------One guide roller 48. 49--One cable core 50--One--Tabe forming device 5
1 ----1------Tave forming body No.l Figure 2Figure 1

Claims (2)

[Claims] (1) A low crosstalk cable comprising a plurality of twisted insulated core wire pairs, including an inner sheath layer provided independently on each twisted insulated core wire to form a cable core, and each of the twisted insulated core wire pairs. A low crosstalk cable comprising: an internal shielding layer that separately covers each of the inner sheath layers to independently shield the internal shielding layer; and an external shielding layer and an outer sheath layer provided on the internal shielding layer. (2) A braiding machine used for manufacturing a low-crosstalk cable in which the internal shielding layer is formed from a shielding tape longitudinally attached to a pair of the cable cores, and the external shielding layer is formed from a braided wire, a tape supply mechanism that supplies the tape; a cable core guide mechanism that guides the pair of cable cores to run on both sides thereof together with the supplied shielding tape; 1. A braiding machine comprising: a tape forming device for vertically applying the shielding tape in an S-shape, and an external shielding layer is provided on the vertically applied shielding tape in a braiding machine main body.