JP6257441B2 - Cable assembly - Google Patents

Description

  The present invention relates to a cable assembly that performs matching of characteristic impedance when a twisted pair cable that performs differential transmission is connected to a connector.

  In cable transmission in the industrial field, high-speed and long-distance transmission technology is required for the purpose of high-speed system and high expandability. In long-distance transmission, transmission by a differential signal using a cable is used.

  FIG. 5 shows a conventional transmission cable and connector. In the differential transmission cable, the characteristic impedance is flattened by the twisted pair signal line 100. In addition, the connection location with the connector 200 improves the connection work efficiency with the connector 200 by loosening the twist (see the twist portion 101), but the distance between the signal lines at the loosened portion (see the assembly portion 102) is increased. Since they are separated from each other, there is a problem that the characteristic impedance increases, signal reflection occurs, and the passing performance deteriorates. FIG. 6 shows an example of a conventional characteristic impedance corresponding to FIG. The rapidly rising part (corresponding to the assembly part 102) becomes a problem part.

  In order to improve the impedance mismatch of the loosened portion, a method is known in which impedance matching is performed by causing the distance between the signal lines to be close by an electric wire holding member (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 2004-71404

  However, in the conventional assembly structure, by loosening the twisted pair cable, the distance between the signal line and the GND is increased, and the parasitic capacitance is reduced, so that the characteristic impedance is increased. When the characteristic impedance is increased, reflection occurs, which causes a problem of deterioration of transmission characteristics.

  Further, as described in Patent Document 1, the characteristic impedance can be lowered to some extent by keeping the distance between the signal lines of the untwisted portions close, but in this case, excessive force is applied to the connector pins. There are problems such as bent connector pins and inability to handle various connector dimensions.

  The present invention has been made to solve the above-described problems, and provides a cable assembly that can cope with various connector dimensions without applying excessive force to the connector pins and can improve transmission efficiency. The purpose is to obtain.

  The cable assembly according to the present invention is a cable assembly for connecting a twisted pair cable to a connector, wherein an insulator is provided between a pair of cables constituting the twisted pair cable, and the side opposite to the side where the insulator of the pair of cables is provided Each of them is provided with a grounded conductor.

  In the cable assembly of the present invention, since an insulator is provided between a pair of cables and a grounded conductor is provided on the side opposite to the side on which the insulator of the pair of cables is provided, an excessive force is applied to the connector pin. Various connector dimensions can be accommodated without adding, and transmission efficiency can be improved.

It is sectional drawing which shows the cable assembly by Embodiment 1 of this invention. It is a block diagram which shows the connection state of the cable assembly and connector by Embodiment 1 of this invention. It is sectional drawing which shows the cable assembly by Embodiment 2 of this invention. It is sectional drawing which shows the cable assembly by Embodiment 3 of this invention. It is a block diagram which shows the connection state of the conventional cable and a connector. It is explanatory drawing which shows the characteristic impedance of the conventional cable.

Embodiment 1 FIG.
FIG. 1 is a cross-sectional view showing a cable assembly according to Embodiment 1 of the present invention. FIG. 2 is a configuration diagram showing a connection state between the twisted pair signal line 100 and the connector 200.
As shown in FIG. 2, the twisted pair signal line 100 is a differential transmission cable in which a pair of cables 100a and 100b in which signal lines 1a and 1b are covered with dielectrics 2a and 2b have a twisted structure. A cable assembly for connecting to the connector 200 is formed at the end. In the cable assembly, the insulator 3 is provided between the pair of cables 100a and 100b, and the conductors 4a and 4b are grounded on the opposite side (outside of the cable) of the pair of cables 100a and 100b. 4b is provided. Further, the pair of cables 100a and 100b, the insulator 3, and the conductors 4a and 4b are integrally fixed by winding the tape 5 around. Further, the twisted pair signal line 100 and the connector 200 are connected by inserting the distal ends of the signal lines 1 a and 1 b into the connector pins 201 provided in the connector 200.

  In the twisted pair signal line 100, the distance between signals is short and the characteristic impedance is stable in the twisted portion. However, when connecting to the connector 200, the twisted pair signal line 100 is connected to loosen the twist for improving workability. In a situation where no countermeasure is taken, the distance between the signal lines is increased, the capacitive coupling is reduced, and the characteristic impedance is increased. Therefore, in the present embodiment, a coupler is constituted by the conductors 4a and 4b and the insulator 3 and attached to the assembly portion.

  The characteristic impedance increases as the capacitive coupling decreases, but the magnitude of the capacitive coupling is affected by the distance between the signal lines 1a, 1b and GND, the dielectric constant of the substance between the signal lines 1a, 1b, and the like. Further, the virtual GND appears to be located at the midpoint between the two signal lines 1a and 1b in the differential signal.

  As shown in FIG. 1, the insulator 3 is installed between the pair of cables 100a and 100b, and the grounded conductors 4a and 4b are provided outside the pair of cables 100a and 100b, thereby adjusting the characteristic impedance to a desired value. Can do. Further, the insulator 3 may be replaceable, and by changing its size, it corresponds to various connectors 200 (intervals between the connector pins 201), and the dielectric constant of the insulator 3 is prepared in many types. Thus, the characteristic impedance can be adjusted to a desired value according to the situation and can be attached. Further, the conductors 4a and 4b and the insulator 3 are covered with a tape 5 to hold these members.

  As described above, according to the cable assembly of the first embodiment, in the cable assembly for connecting the twisted pair cable to the connector, the insulator is provided between the pair of cables constituting the twisted pair cable, and the pair of cables are insulated. Since the grounded conductors are provided on the side opposite to the side on which the body is provided, various connector dimensions can be accommodated without applying excessive force to the connector pins, and transmission efficiency can be improved.

  In addition, according to the cable assembly of the first embodiment, since the insulator can select at least one of size and dielectric constant, the characteristic impedance can be adjusted to a desired value.

Embodiment 2. FIG.
In the second embodiment, a spacer 6 is provided in a portion where the insulator 3 is located, and the distance between the pair of cables 100a and 100b is adjusted.
FIG. 3 is a cross-sectional view showing the cable assembly of the second embodiment. As illustrated, in the second embodiment, a spacer 6 made of an insulator is provided between the divided insulators 3a and 3b. Since the other configuration is the same as that of the first embodiment shown in FIG.

  In the cable assembly according to the second embodiment configured as described above, by preparing various spacers 6, even when the sizes of the insulators 3a and 3b are fixed, the distance between the signal lines 1a and 1b is arbitrarily selected. It is possible to cope with various connectors 200, and by preparing the spacer 6 having a different dielectric constant, the characteristic impedance can be adjusted by changing the dielectric constant of the spacer 6.

  In the above example, the insulator is divided into two parts, and the spacers 6 are provided therebetween. However, the relationship between the insulators and the spacers 6 is not limited to this, and the number of divisions of the insulators can be further increased. Alternatively, the spacer 6 may be provided between the insulator 3 and the cable 100a (or the cable 100b) without dividing the insulator 3.

  As described above, according to the cable assembly of the second embodiment, since the spacer is provided in the portion where the insulator is located, it is possible to cope with various connectors by selecting the size of the spacer. By selecting the dielectric constant, the characteristic impedance can be easily adjusted.

Embodiment 3 FIG.
In the third embodiment, the tape 5 in the first embodiment is a conductor tape 7.
FIG. 4 is a cross-sectional view showing the cable assembly of the third embodiment. In the third embodiment, the conductors 4a and 4b, the insulator 3, and the pair of cables 100a and 100b are surrounded by the conductive tape 7 having conductivity so that these members are integrally held. The conductor tape 7 is assumed to be grounded. The other configuration is the same as that of the first embodiment shown in FIG.

  In the cable assembly configured as described above, since the conductive tape 7 has conductivity, the characteristic impedance adjustment by the conductive tape 7 is also possible.

  In the above example, the conductor tape 7 is applied to the configuration of the first embodiment, but may be applied to the configuration of the second embodiment. That is, the structure provided with the spacer 6 in this Embodiment may be sufficient. By adopting such a configuration, it is possible to cope with various connectors 200 and further facilitate adjustment of characteristic impedance.

  As described above, according to the cable assembly of the third embodiment, since the pair of cables, the insulator, and the conductor are integrally surrounded by the conductor tape and the conductor tape is grounded, the characteristic impedance can be further easily adjusted. Can be done.

  In the present invention, within the scope of the invention, any combination of the embodiments, or any modification of any component in each embodiment, or omission of any component in each embodiment is possible. .

  1a, 1b Signal line, 2a, 2b Dielectric, 3 Insulator, 4a, 4b Conductor, 5 Tape, 6 Spacer, 7 Conductor tape, 100 Twisted pair signal line, 100a, 100b A pair of cables, 200 connectors, 201 Connector pins.

Claims (4)

In a cable assembly that connects a twisted pair cable to a connector,
An insulator is provided between a pair of cables constituting the twisted pair cable,
And,
A cable assembly, wherein grounded conductors are provided on opposite sides of the pair of cables to the side on which the insulator is provided.   The cable assembly according to claim 1, wherein a spacer is provided at a portion where the insulator is located.   The cable assembly according to claim 1, wherein at least one of a size and a dielectric constant of the insulator is selectable.   The cable according to any one of claims 1 to 3, wherein the pair of cables, the insulator, and the conductor are integrally surrounded by a conductor tape, and the conductor tape is grounded. assembly.

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