JPH058826U - Many-pair cable - Google Patents

Abstract

(57) [Summary] [Purpose] With a relatively simple structure, while maintaining sufficient mechanical strength without impairing the flexibility of the multi-pair cable, SCSI
An object is to provide a multi-pair cable that can satisfy the interface standard. [Structure] A multi-pair cable 1 is provided with 24 sets of signal cores (first assembled wires) 4 in which a first core wire 3 in which a conductor 21 having a single wire structure is covered with an insulator 14 is twisted, and thin wires 5a and 5a are provided. ,,, 5
One set of a power source core (first assembled wire) 2 in which wire cores (second core wires) 5 and 5 in which a conductor 22 in which seven pieces of a are twisted are covered with an insulator 14 is twisted, and a total of 25 pairs are provided. A pair of twisted insulated wire group 36 having the above-described configuration is formed, a holding winding tape (insulating intervening layer) 7 is wound on the outer side thereof, a shield layer 8 made of a braid is provided thereon, and a sheath layer 9 is provided on the outer side thereof. It is composed.
The twisted pair insulated wire group 36 has three sets of signal cores 4 at the center.
8 layers of signal cores 4 are formed on the outer side of the first layer A by forming the first layer A.
To form a second layer B, and 13 sets of signal cores 4 and one set of power supply cores 2 are arranged on the outside thereof to form a third layer C.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an improvement of a multi-pair cable.

[0002]

[Prior Art]

Generally, a multi-pair cable using a large number of twisted pair wires as shown in FIG. 5 is used for interface signal connection between electronic device terminals, particularly between computers. This multi-pair cable 10 is a twisted pair insulation in which a conductor 12 formed by twisting seven thin wires 3a, 3a, ..., 3a is covered with an insulator 14 (core wire) 15, 15 (see FIG. 6). 3 sets are arranged around the wire 17 to form the first layer A, and 8 sets of twisted pair insulation wires are arranged on the outside thereof to form the second layer B, and 14 sets of twisted pair insulation are formed on the outside thereof. Outside the three-layered twisted pair insulated wire group 26 consisting of 25 pairs of twisted pair insulated wires 17, 17, ..., 17 in which the wires 17 are arranged to form the third layer C, a holding tape ( An insulating intervening layer) 7 is wound, a shielding layer 8 made of a braid is provided on the winding, and a sheath layer 9 is provided outside the shielding layer 8. Generally the characteristic impedance Z ₀ of such many-cable 10, the diameter of the conductor 12 d, if the distance between conductor 12 and B (see FIG. 2) of the first two twisted wire characteristic impedance Z _A Obtained by equation (1),

[0003]

[Equation 1]

Next, the characteristic impedance Z ₀ of the multi-pair cable 10 is obtained by the equation (2).

Z ₀ = [0.65-0.3exp (−0.22n)] Z _A [Ω] (2) However, n: logarithm (N ≧ 2) Z _A : double twist without shielding It can be said that the characteristic impedance of the wire (twisted pair wire 17), that is, the characteristic impedance Z ₀ increases or decreases depending on the distance B between the conductors 12 and 12 and the relative permittivity ε _e of the insulator 14.

In recent years, for example, a small computer system (SCSI) interface standard, that is, a high impedance Z _X = 100 ± 10 [Ω] has been standardized, and the characteristic impedance Z ₀ of the multi-pair cable 10 meets this standard. It is necessary to make the impedance high. The SCSI interface standard is as shown in Table 1.

[0007]

[Table 1]

For example, when a multi-pair cable 10 having a conductor size of 28 AWG (7 wires / 0.130 mmΦ) and an outer diameter of the core wire 15 of 0.88 [mmΦ] is formed, a finished outer diameter of 12 [mmΦ] results in a characteristic impedance Z. ₀ becomes 93 [Ω].

[0009]

[Problems to be solved by the device]

 However, the above-mentioned multi-pair cable 10 satisfies the SCSI interface standard, but has a large core wire outer diameter = 0.88 [mmΦ], and the finished outer diameter of the multi-pair cable 10 is 12 [mmΦ], which makes it When the D-SUB connector or the like is attached to the terminal portion, the flexibility of the cable 10 is lowered, and the connector is easily detached from the device side connection portion due to the cable rigidity.

In addition, when the number of pairs is 25 or more, for example, 35 pairs, the finished outer diameter of the multi-pair cable 10 is further increased, the flexibility of the multi-pair cable 10 is further reduced, and in the worst case, the D- There was a problem that the connector cover could not be attached after the SUB connector was attached. In this case, the outer diameter of the core wire 15 may be reduced, but in this case, from the above formula (1), the characteristic impedance Z ₀ is lowered, and the SCSI interface standard cannot be satisfied. When the relative permittivity ε _e of the insulator 14 of each core wire 15 is reduced (the degree of foaming is increased), the outer diameter of the core wire 15 becomes thicker and the strength of the core wire 15 decreases, resulting in the reliability of the product. There was an inconvenience that it dropped significantly.

[0011]

[The purpose of the device]

 The present invention improves the disadvantages of the conventional example described above, and with a relatively simple structure, it can satisfy the SCSI interface standard while maintaining sufficient mechanical strength without impairing the flexibility of the multi-pair cable. The purpose is to provide a twin cable.

[0012]

[Means for Solving the Problems]

 Therefore, in the present invention, a plurality of pairs of first core wires in which a plurality of first core wires each having a coating layer provided on a conductor of a single wire structure are twisted in pairs and a twisted wire conductor in which a plurality of thin wire conductors are twisted It is intended to achieve the above-mentioned object by adopting a constitution in which a shielding layer and a sheath layer are provided outside a second assembly line composed of at least one second core wire provided with a coating layer. .

[0013]

【Example】

 An embodiment of the present invention will be described below with reference to FIGS. Here, the same components as those of the above-mentioned conventional example are designated by the same reference numerals. The multi-pair cable 1 shown in FIG. 1 includes a signal core (first assembled wire) formed by pair-twisting a first core wire 3 in which a conductor 21 having a single wire structure is covered with an insulator 14 as shown in FIG. ) 4 are provided in 24 sets, and the thin wires 5a, 5a, ..., 5a are twisted into seven as shown in FIG. 3 (b). The conductor 22 covered with the insulator 14 (second core wire) 5, 5 One pair of power supply cores (first assembled wire) 2 twisted with each other are provided, and a pair twisted insulated wire group 36 of 25 pairs is formed as a whole, and a holding winding tape (insulating intervening layer) 7 is provided on the outside thereof. The shield layer 8 is wound, the shield layer 8 made of a braid is provided thereon, and the sheath layer 9 is provided outside the shield layer 8. In the twisted pair insulated wire group 36, like the above-described conventional multi-pair cable 10, three sets of signal cores 4 are arranged in the center to form the first layer A, and eight sets of signals are arranged outside thereof. The core 4 is arranged to form the second layer B, and 13 sets of the signal cores 4 and one set of the power supply cores 2 are arranged on the outside thereof to form the third layer C.

Here, for example, as the core wire of the present embodiment, it is assumed that a single wire structure 30 AWG is used for the signal core 4 and a twisted wire structure 28 AWG is used for the power supply core 2.

If the signal core 4 is a single wire structure 30 AWG conductor 21 (1 wire / 0.26 mm Φ) and the power supply core 2 is a stranded wire structure 28 AWG conductor 22 (7 wires / 0.13 mm Φ), the former is The latter has a cross-sectional area of about 0.05 [mm ² ] and the cross-sectional area of about 0.093 [mm ² ]. For example, using a 28 AWG core wire pressure welding (IDC) connector 50 with a stranded wire structure as shown in FIG. 4 (a). When connecting to the connecting piece 51, the 30 AWG having a single wire structure has a smaller cross-sectional area than the 28 AWG having a twisted wire structure, and therefore the 30 AWG can be collectively connected to the connecting piece 51. The outer diameters of the core wire 3 and the core wire 5 are preferably 0.68 [mm Φ] and preferably have the same structure. According to the experiments by the inventors, when the transmission loss of the multi-pair cable is measured, the conventional multi-pair cable 10 has a twisted wire structure of 28 AWG, 25 pairs and the single wire structure of the present embodiment of 30 AWG, 24 pairs, a twisted wire. When compared with the 28 AWG, 1 pair of structure, the attenuation amount is almost unchanged, and both multi-pair cables 1 (10) satisfy the SCSI-2 attenuation standard (0.095 db / mm at.5MHZ), It has been found that the conductor can be a single wire structure 30 AWG. Further, according to this configuration, the characteristic impedance Z ₀ of the 25 pairs of multi-pair cables 1 is about 100 [Ω], the finished outer diameter is 9.5 [mmΦ], and the characteristic impedance Z ₀ of the 35 pairs of multi-pair cables 1 is A cable with a finished outer diameter of 11 [mm Φ] could be constructed with about 100 [Ω].

It should be noted that the power source core 2 does not have to have a twisted pair structure, and may have only one.

Since the present embodiment is configured as described above, according to this, it is possible to reduce the diameter by 2 [mm] as compared with the outer shape of the conventional multi-pair cable 10 while satisfying the SCSI standard. If the outer diameters of the core wire 3 and the core wire 5 are the same, the IDC connectors having the same diameter can be fitted together, and the power supply core 20 does not need to be subjected to a separate process as in the conventional case. The terminal processing work can be simplified.

[0018]

[Effect of the device]

 Since the present invention is configured as described above, it satisfies the SCSI interface standard while maintaining a sufficient mechanical strength without compromising the flexibility of the multi-pair cable with a relatively simple configuration. Can provide a multi-pair cable.

[Brief description of drawings]

FIG. 1 is a cross-sectional configuration diagram of a multi-pair cable according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of core wires according to the present embodiment and a conventional example.

FIG. 3 is an explanatory diagram of a core wire of the multi-pair cable of FIG.

4 is an explanatory view of a pressure welding process of the multi-pair cable of FIG.

FIG. 5 is a cross-sectional configuration diagram of a conventional multi-pair cable.

6 is an explanatory view of core wires of the multi-pair cable of FIG.

[Explanation of symbols]

 1 ... Multi-pair cable 2 ... Second aggregate line 3 ... First core line 4 ... First aggregate line 5 ... Second core line 14 ... Insulator 8 ... ...... Shield layer 9 …… Sheath layer 21 …… Single wire conductor 22 …… Twisted wire conductor 36 …… Twisted insulated wire group

Claims (1)

[Claims for utility model registration] [Claim 1] A plurality of pairs of first core wires each having a plurality of first core wires each having a coating layer provided on a conductor having a single wire structure, and a plurality of thin wire conductors. A multi-pair cable, characterized in that a shielding layer and a sheath layer are provided on the outside of a second assembled wire composed of at least one second core wire in which a coating layer is provided on the twisted wire conductors that are twisted together.