JP2003346566A - Transmission cable and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce an internal skew in a cable by preventing difference in the length of insulating wires from easily occurring even if the cable is bent. <P>SOLUTION: In the transmission cable 1, the insulating wire 9 is composed by providing a fusion layer 7 at the outer periphery of an insulating layer 5 for covering a signal line 3, and a plurality of insulating wires 9 allow each insulating layer 5 to be fused and joined each other via the fusion layer 7, thus preventing the difference in the length of the signal lines 3 from being increased since the plurality of insulating wires 9 cannot slide easily even if the transmission cable 1 is bent, and hence reducing the internal skew in the cable 1. <P>COPYRIGHT: (C)2004,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a transmission cable, for example, a coaxial cable and a transmission cable, and more particularly to a method for high-speed data transmission used for internal wiring of various communication equipment and large equipment such as computers. The present invention relates to a motion signal transmission cable and a method for manufacturing the same.

[0002]

2. Description of the Related Art Referring to FIG. 4, in a conventional transmission cable 101 for high-speed data transmission, a pair of signal lines 103 (center conductors) are separately sheathed by an insulating layer 105 made of an insulating material such as resin. And is extruded to form the insulated wire 107. A drain wire 109 is attached to these two insulated wires 107 and is tape-wrapped with a conductive tape 111 such as an aluminum tape as an external conductor, and is shielded. By applying the positive and negative potentials to the pair of two-core signal lines 103, a differential voltage signal is transmitted.

[0003]

By the way, in the structure of the conventional transmission cable 101, when the cable 101 is bent, the two insulated wires 107 slip and the difference in length between the insulated wires 107 tends to occur. In addition, there is a problem that a difference in propagation delay time between the signal lines 103 tends to occur. In other words, when a signal of a differential voltage is sent by applying a potential of + and-to the pair of signal lines 103, the transmission signal speed of the pair of signal lines 103 is different, and the effect thereof is given. As a result, there is a problem that an intra-pair skew (intra-pair propagation delay difference) occurs.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to reduce the in-pair skew of a cable by making it difficult for a difference in length between the insulated wires even when the cable is bent. An object of the present invention is to provide a transmission cable and a manufacturing method thereof.

[0005]

According to a first aspect of the present invention, there is provided a transmission cable according to the first aspect of the present invention, wherein a fusion layer is provided on an outer periphery of an insulation layer covering a signal line to form an insulation line. A plurality of insulated wires are formed by fusing and joining each of the insulating layers via the fusing layer.

Accordingly, since the insulating layers of the insulated wires are fusion-bonded to each other through the fusion layer, even if the cable is bent, the plurality of insulated wires are less likely to slip, so that the length of the signal lines is reduced. The difference is suppressed. As a result, the in-pair skew of the cable is suppressed and reduced.

According to a second aspect of the present invention, there is provided the transmission cable according to the first aspect, wherein the fusion layer is made of a heat-meltable or solvent-meltable fusing agent. .

[0008] Therefore, since the fusion agent is easily melted by heating or a solvent, the insulating layers are easily fusion-bonded to each other via the fusion layer.

According to a third aspect of the present invention, there is provided a transmission cable according to the present invention, wherein the outer periphery of the signal line is sheathed with an insulating layer made of an insulating material by extrusion molding, and then a fusion layer is applied to the outer periphery of the insulating layer. Is formed in advance, the fusion layers of the plurality of insulated wires are melted in advance, and then the plurality of insulated wires are substantially parallel to each other and shielded with an external conductor from the outside thereof, thereby forming the plurality of insulated wires. An insulating layer is fusion-bonded via the fusion layer.

Therefore, the operation is similar to that of the first aspect, and since the insulating layers of the insulated wires are fusion-bonded via the fusion layer, even if the cable is bent, the plurality of insulated wires slide. This makes it difficult to reduce the difference in length between the signal lines. As a result, the in-pair skew of the cable is suppressed and reduced.

According to a fourth aspect of the present invention, in the method for manufacturing a transmission cable according to the third aspect, a heat-meltable or solvent-meltable fusing agent is used for the fusion layer. It is characterized by the following.

[0012] Therefore, the operation is the same as that of the second aspect, and since the fusing agent is easily melted by heating or a solvent, the insulating layers are easily fusion bonded via the fusing layer.

[0013]

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

Referring to FIG. 1, a transmission cable 1 for high-speed data transmission according to this embodiment includes a pair of signal lines 3 (center conductors) in this embodiment.
The core signal line 3 (center conductor) is separately sheathed with an insulating layer 5 made of an insulating material such as resin, and a fusion layer 7 is applied to the outer periphery of each insulating layer 5 to form an insulating wire 9. Is composed. The fusion layer 7 may be made of, for example, a nylon-based thermoplastic adhesive as the heat-meltable fusion agent 19, or an alcohol-soluble fusion agent as the solvent-meltable fusion agent 19, for example. Is used.

Further, the two insulating lines 9 are provided substantially parallel to the outside of the insulating layer 5 so that the drain line 11 is located, for example, between the pair of signal lines 3. I have. The two insulating wires 9 and the drain wire 11 are wound around the outside with a conductive tape 13 such as an aluminum tape as an external conductor and shielded, and the insulating layer 5 of the two insulating wires 9 is melted. They are fusion-bonded to each other via a bonding layer 7.

The above-mentioned drain line 11 may be plural or may be provided at another position.

Next, a method of manufacturing the transmission cable 1 according to this embodiment will be described.

Referring to FIG. 2, each of the insulating wires 9 is formed by extruding the signal wire 3 after being sheathed by an extruder 15 with an insulating layer 5 made of an insulating material such as a resin.
Is provided with a fusion layer 7 on the outer periphery of. In this case, the insulating layer 5 provided with the extruded signal line 3 is impregnated with the above-mentioned nylon-based thermoplastic adhesive or alcohol-soluble fusion agent 19 in the fusion agent tank 17 so that the insulation layer 5 is insulated. A fusion layer 7 is applied to the outer periphery of the layer 5.

Referring to FIG. 3, two insulated wires 9 are provided.
In this embodiment, the fusion layer 7 is, for example, a nylon-based thermoplastic adhesive as a heat-fusible fusion agent 19, so that hot air is blown in a heater 21 as a fusion means. And heated and melted. When the fusion layer 7 is, for example, alcohol-soluble as the solvent-melting fusion agent 19, the solvent, for example, alcohol is applied and melted.

Next, the drain wire 11 is sent out to the outside of the insulating layer 5 of these two insulated wires 9 so as to be substantially parallel to each other, and the drain wire 11 and the two insulated wires 9 are wound on a tape winding device 23. Then, the tape is wound from the outside with a conductive tape 13 such as an aluminum tape, shielded, and then wound.

In this embodiment, two insulated wires 9 are used.
Is heated (or coated with alcohol) to melt the adhesive layer 7 on the outer periphery of the insulating layer 5 in advance, so that when the conductive tape 13 is wound, the insulating layer 5 of the two insulating wires 9 is wound.
Are fusion bonded to each other via the fusion layer 7.

According to the above configuration, since the transmission cable 1 has the insulating layers 5 of the signal lines 3 fused to each other via the fusion layer 7, even if the transmission cable 1 is bent, the two insulating wires 9 are formed. Since there is no slip, the difference in length between the two insulated wires 9 is suppressed. As a result, a difference in the length of the pair of signal lines 3 is less likely to occur, so that it is possible to suppress and reduce in-pair skew (in-pair propagation delay time difference).

Since the above-mentioned fusing agent 19 is easily melted by heating or a solvent, the insulating layer 5 of the two insulated wires 9 is formed.
Are easily fusion bonded to each other via the fusion layer 7.

The present invention is not limited to the above-described embodiment, but can be implemented in other modes by making appropriate changes.

[0025]

As will be understood from the above description of the embodiments of the present invention, according to the first aspect of the present invention, the insulating layers of the signal lines are fusion-bonded to each other via the fusion layer. So
Even if the cable is bent, the sliding of the plurality of insulated wires can be suppressed, and the difference in length between the signal wires can be suppressed. As a result, in-pair skew of the cable can be reduced.

According to the second aspect of the present invention, since the fusion agent can be easily melted by heating or a solvent, the insulating layers can be easily fusion-bonded to each other via the fusion layer.

According to the third aspect of the invention, the effect is the same as that of the first aspect, and the insulating layers of the signal lines are fusion-bonded to each other via the fusion layer. Also, it is possible to suppress slippage of a plurality of insulated wires and to suppress a difference in length between signal wires. As a result, in-pair skew of the cable can be reduced.

According to the fourth aspect of the invention, the effect is the same as that of the second aspect, and since the fusing agent can be easily melted by heating or a solvent, the insulating layers are easily fused via the fusing layer. Can be joined.

[Brief description of the drawings]

FIG. 1 is a sectional view of a transmission cable according to an embodiment of the present invention.

FIG. 2 is a schematic explanatory view of a method of manufacturing the transmission cable according to the embodiment of the present invention.

FIG. 3 is a schematic explanatory view of a method of manufacturing the transmission cable according to the embodiment of the present invention.

FIG. 4 is a sectional view of a conventional transmission cable.

[Explanation of symbols]

1 Transmission cable 3 signal line (center conductor) 5 Insulating layer 7 Fusion layer 9 Insulated wire 11 Drain wire 13 Conductive tape (outer conductor) 15 Extrusion molding machine 17 Fusing agent tank 19 Fusing agent 21 heating machine (melting means) 23 Tape winding device

Claims (4)

[Claims] An insulation wire is provided by providing a fusion layer on the outer periphery of an insulation layer covering a signal line, and a plurality of the insulation wires are fusion-bonded to each other through the fusion layer. A transmission cable, comprising: 2. The transmission cable according to claim 1, wherein the fusing layer is made of a heat-fusible or solvent-fusible fusing agent. 3. An outer periphery of the signal line is sheathed with an insulating layer made of an insulating material by extrusion molding, and then a fusion layer is formed on the outer periphery of the insulating layer to form an insulating line. After melting the fusion layer, the plurality of insulated wires are made substantially parallel to each other and shielded with an external conductor from the outside, whereby the insulation layers of the plurality of insulated wires are fused through the fusion layer. A method for manufacturing a transmission cable, comprising joining. 4. The method according to claim 3, wherein a heat-meltable or solvent-meltable fusing agent is used for the fusing layer.