JP2012048829A - Composite cable - Google Patents

Abstract

The present invention provides a composite cable that can have excellent flexibility and can suppress deterioration of an optical signal at a bent place.
A composite cable includes an optical fiber bundle having a first optical fiber arranged linearly and at least one second optical fiber wound spirally around the first optical fiber. And at least one electric wire 50 wound spirally around the optical fiber bundle 30.
[Selection] Figure 1

Description

  The present invention relates to a composite cable, and more particularly to a composite cable that has excellent flexibility and can suppress deterioration of an optical signal at a bent place.

  A composite cable in which an optical fiber that transmits an optical signal and an electric wire that transmits an electric signal or electric power are combined is known. Such composite cables are used in industrial machines, video equipment, and the like. For example, when composite cables are used in video equipment, large-capacity signals such as image information are transmitted by optical fiber, and are used for voice and text. Information etc. are transmitted by electric wires.

  Patent Document 1 below describes such a composite cable. In this composite cable, one optical fiber is provided in a straight line at the center, an outer covering layer that covers the outer peripheral surface of the optical fiber is provided, and a plurality of electric wires are provided on the outer peripheral surface of the outer covering layer. Is provided. This electric wire is spirally wound on the outer peripheral surface of the outer covering layer. Thus, this composite cable is supposed to be excellent in flexibility by winding the electric wire in a spiral shape.

Japanese Unexamined Patent Publication No. 63-4504

  However, in the composite cable described in Patent Document 1, an optical fiber that transmits an optical signal is linearly provided. Therefore, although this composite cable is excellent in bendability, when it is bent, stress concentrates on the bent portion of the optical fiber, and the refractive index changes due to the concentration of the stress, so that the optical signal may be deteriorated.

  Therefore, an object of the present invention is to provide a composite cable that has excellent flexibility and can suppress deterioration of an optical signal at a bent place.

  In order to solve the above problems, a composite cable of the present invention is a light having a first optical fiber arranged in a straight line and at least one second optical fiber wound spirally around the first optical fiber. It comprises a fiber bundle and at least one electric wire spirally wound around the optical fiber bundle.

  According to such a composite cable, it is possible to transmit electric power and an electric signal through electric wires, and to transmit an optical signal through at least the second optical fiber. In addition, since the second optical fiber and the electric wire are spirally wound around the first optical fiber and the optical fiber bundle, respectively, the second optical fiber and the electric wire are in a place where the composite cable is bent. The position shifts slightly in the length direction of the second optical fiber or the electric wire. Thus, the composite cable can have excellent flexibility. Further, when the composite optical cable is bent due to the positional deviation of the second optical fiber, stress is suppressed from being concentrated on a part of the second optical fiber, and an optical signal is transmitted by the second optical fiber. It is possible to suppress the deterioration of the optical signal when it is performed.

  Moreover, it is preferable that the composite cable further includes a tape spirally wound around the electric wire so as to cover the optical fiber bundle and the electric wire.

  According to such a composite cable, it is possible to prevent the electric wire and the second optical fiber from being scattered by the tape. And since the tape is wound spirally, it can suppress that the flexibility of a composite cable is inhibited.

  Preferably, the composite cable further includes a coating layer that covers the optical fiber bundle, and the electric wire is spirally wound around the optical fiber bundle via the coating layer.

  According to such a composite cable, the second optical fiber can be prevented from being displaced in the lateral direction of the second optical fiber by the coating layer, and the second optical fiber can be prevented from being unevenly distributed. In this way, it is possible to prevent stress from being concentrated on some of the second optical fibers due to the uneven distribution of the second optical fibers.

  In the composite cable, it is preferable that the first optical fiber and the second optical fiber have the same diameter, and the number of the second optical fibers is six.

  According to such a composite cable, the diameter of the optical fiber bundle can be reduced by densely filling the second optical fiber.

  In the composite cable, the first optical fiber is preferably a dummy fiber that does not transmit an optical signal.

  Since the second optical fiber is spirally wound around the first optical fiber, the second optical fiber has different lengths with respect to a certain length of the composite cable. Therefore, according to such a composite cable, since the optical signal is transmitted only by the second optical fiber, it is possible to prevent the transmission time of the optical signal from being different.

  In the composite cable, it is preferable that a pitch at which the second optical fiber is spirally wound is larger than a pitch at which the electric wire is spirally wound.

  According to such a composite cable, it is possible to suppress an increase in the curvature of the second optical fiber, and it is possible to suppress deterioration due to bending loss of an optical signal transmitted through the second optical fiber. Moreover, since the electric wire arrange | positioned at the outer peripheral side of a composite cable receives the influence by the bending of a composite cable more strongly, the flexibility of a composite cable can be improved more by winding an electric wire with a small pitch. In addition, the pitch in this specification means the distance along the length direction of a composite cable in case an optical fiber or an electric wire is wound once in a spiral.

  The first optical fiber and the second optical fiber are preferably optical fibers having a glass core and cladding.

  By comprising in this way, physical properties, such as a linear expansion coefficient, of a 1st optical fiber and a 2nd optical fiber can be made equal. Therefore, even if the first and second optical fibers expand and contract due to a change in environmental temperature, it is possible to suppress excessive stress from being applied to the second optical fiber, and it is possible to suppress deterioration of the optical signal.

  As described above, according to the present invention, there is provided a composite cable that has excellent flexibility and can suppress deterioration of an optical signal at a bent place.

It is a side view which shows the composite cable which concerns on embodiment of this invention. It is a figure which shows the mode of the structure in a cross section perpendicular | vertical to the longitudinal direction of the composite cable of FIG. It is a figure which shows the mode of the structure in the cross section perpendicular | vertical to the longitudinal direction of the 1st, 2nd optical fiber of FIG. It is a figure which shows the mode of the structure in a cross section perpendicular | vertical to the longitudinal direction of the electric wire of FIG.

  Hereinafter, a preferred embodiment of a composite cable according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a side view showing a composite cable according to an embodiment of the present invention, and FIG. 2 is a view showing a structure in a cross section perpendicular to the longitudinal direction of the composite cable of FIG.

  As shown in FIGS. 1 and 2, the composite cable 1 includes an optical fiber bundle 30 having one first optical fiber 10 and a plurality of second optical fibers 20 wound around the first optical fiber 10; A coating layer 40 that covers the optical fiber bundle 30, a plurality of wires 50 that are spirally wound around the coating layer 40, a tape 60 that is spirally wound around the wires 50 so as to cover the wires 50, and a tape 60 And a sheath 70 for covering the main body.

  FIG. 3 is a view showing a structure in a cross section perpendicular to the longitudinal direction of the first and second optical fibers 10 and 20 of FIG. As shown in FIG. 3, the first optical fiber 10 includes a core 11, a clad 12 that covers the outer peripheral surface of the core 11, and a protective layer 13 that covers the outer peripheral surface of the clad 12. The two optical fiber 20 includes a core 21, a clad 22 that covers the outer peripheral surface of the core 21, and a protective layer 23 that covers the outer peripheral surface of the clad 22 as main components. The fiber 10 and the second optical fiber 20 have the same configuration. Therefore, the structure and material of the first optical fiber 10 will be described below.

  The clad 12 has a refractive index lower than that of the core 11, and is configured so that light propagates through the core 11. In addition, the size of each component in the optical fiber 10 is not particularly limited because it is appropriately selected depending on the application. For example, the diameter of the core 11 is 4 μm to 50 μm, and the outer diameter of the cladding 12 is Is 100 μm to 200 μm, and the outer diameter of the protective layer 13 is 170 μm to 350 μm.

Moreover, as a material which comprises the core 11, the quartz etc. to which the dopant which makes a refractive index high are added are mentioned, for example. Examples of such a dopant include germanium oxide (GeO ₂ ) and aluminum oxide (Al ₂ O ₃ ). Examples of the material constituting the clad 12 include quartz to which no dopant is added and quartz to which a dopant that lowers the refractive index such as fluorine (F) is added. Moreover, as a material which comprises the protective layer 13, ultraviolet curable resin, such as an acrylate, is mentioned, for example.

  Moreover, the 1st optical fiber 10 is arrange | positioned at linear form. This linear arrangement means that the composite cable 1 is arranged along the longitudinal direction. When the composite cable 1 is linear, the first optical fiber 10 is also linear. I mean. A plurality of second optical fibers 20 are spirally wound on the outer peripheral surface of the first optical fiber 10. The pitch of the second optical fiber 20 wound spirally is not particularly limited, but is about 100 mm in the present embodiment.

  As shown in FIG. 2, in the present embodiment, the diameters of the first optical fiber 10 and the second optical fiber 20 are the same, and six second optical fibers 10 are arranged on the outer peripheral surface of the first optical fiber 10. The optical fiber 20 is wound spirally. This is preferable because the second optical fiber 20 can be closely packed on the outer peripheral surface of the first optical fiber 10 to reduce the diameter of the optical fiber bundle 30.

  Thus, the second optical fiber 20 is spirally wound on the outer peripheral surface of the first optical fiber 10 to form an optical fiber bundle 30. As described above, the optical fiber bundle 30 is covered with the coating layer 40. ing. The coating layer 40 has a circular outer shape in a cross section perpendicular to the longitudinal direction, and covers the optical fiber bundle 30 by, for example, extrusion molding. The diameter of the coating layer 40 is not particularly limited, but is 0.75 mm to 2.0 mm. Although it does not restrict | limit especially as a material of the coating layer 40, For example, resin, such as polyethylene and a polypropylene, can be mentioned.

  FIG. 4 is a diagram illustrating a structure in a cross section perpendicular to the longitudinal direction of the electric wire 50. As shown in FIG. 4, the electric wire 50 includes a conductive wire 51 made of a stranded metal wire and an insulating layer 52 that covers the outer periphery of the conductive wire 51. Although the diameter of this electric wire 50 is not specifically limited, It shall be 0.2 mm-2.0 mm. Moreover, as a material of the conducting wire 51 of the electric wire 50, if it is a conductor, it will not specifically limit, Copper, iron, nickel, aluminum etc. can be mentioned. Furthermore, the material of the insulating layer 52 is preferably a material having excellent properties such as flame retardancy, water resistance, and insulation. Such materials include ethylene materials such as polyethylene, ethylene vinyl acetate copolymer and ethylene ethyl acrylate copolymer, and composite resins blended with polyolefins such as polypropylene, ethylene propylene rubber and styrene elastomer. Examples of the base include metal hydroxides such as magnesium hydroxide and aluminum hydroxide, or phosphoric acid esters, and fluororesins.

  The plurality of electric wires 50 having such a configuration are spirally wound on the outer peripheral surface of the coating layer 40 as described above, and the pitch at which the electric wires 50 are wound is such that the second optical fiber 20 is spirally wound. The pitch is preferably smaller than the pitch, and in this embodiment, the pitch is 10 mm. The direction in which the electric wire 50 is spirally wound is the same as the direction in which the second optical fiber is wound as shown in FIG. Since the two optical fibers 20 are displaced in the same direction, it is preferable from the viewpoint of improving the flexibility of the composite cable 1.

  Further, the electric wire 50 is covered with a tape 60. The tape 60 is a resin or metal tape, and is wound spirally as shown in FIG. Examples of the resin constituting the tape 60 include polyethylene terephthalate, and examples of the metal include aluminum and copper. The direction in which the tape 60 is spirally wound is the direction opposite to the direction in which the electric wire 50 is wound as shown in FIG. 1, so that when the composite cable 1 is bent, the electric wire tends to be displaced. The direction in which the tape is to be displaced and the direction in which the tape is about to be displaced are opposite to each other, so that the displacement of the wire becomes too large or the displacement of the wire cannot be restored. This is preferable from the viewpoint of preventing separation and maintaining the shape of the composite cable 1. Note that an adhesive may be applied to the surface of the tape 60 on the electric wire 50 side.

  The sheath 70 covering the outer peripheral surface of the tape 60 is formed by extrusion molding, and the outer shape in a cross section perpendicular to the longitudinal direction is circular. Examples of the material of the sheath 70 include the same material as that of the insulating layer 52 of the electric wire 50.

  In the composite cable 1 described above, each electric wire 50 transmits an electric signal and electric power, and at least the second optical fiber 20 transmits an optical signal. In this case, it is preferable not to transmit an optical signal using the first optical fiber 10 as a dummy fiber. This is because the first optical fiber 10 is not spirally wound, and stress may concentrate when the composite cable 1 is bent. However, an optical signal may be transmitted by the first optical fiber 10.

  As described above, according to the composite cable 1 of the present embodiment, power and electrical signals can be transmitted by the electric wires 50, and optical signals can be transmitted by at least the second optical fiber 20. Further, since the plurality of second optical fibers 20 and the plurality of electric wires 50 are respectively wound spirally, the second fiber 20 and the electric wires 50 are combined when the composite cable 1 is bent. In the place where the cable 1 bends, the position shifts slightly in the length direction. That is, in the part where the composite cable 1 is bent, the first optical fiber 10 is used as a reference and moves slightly to the outside of the second optical fiber located inside. Thus, the composite cable 1 can have excellent flexibility. Further, when the second optical fiber 20 is displaced in the length direction of the second optical fiber 20, stress is concentrated on a part of the second optical fiber 20 when the composite cable 1 is bent. It is suppressed. Therefore, a change in the refractive index of a part of the second optical fiber 20 is suppressed, and deterioration of the optical signal when the optical signal is transmitted by the second optical fiber 20 can be suppressed.

  Furthermore, in the composite cable 1, it is possible to prevent the electric wire 50 and the second optical fiber 20 from being scattered by the tape 60. And since this tape 60 is wound spirally, it can suppress that the flexibility of the composite cable 1 is inhibited.

  Furthermore, in the composite cable 1, the second optical fiber 20 is prevented from being displaced in the lateral direction of the second optical fiber 20 by the coating layer 40 when the composite cable 1 is bent. It is possible to prevent the fiber 20 from being unevenly distributed. Thus, it is possible to prevent stress from being concentrated on some of the second optical fibers 20 by gathering the second optical fibers 20.

  In the case where the first optical fiber 10 is a dummy fiber and the optical signal is transmitted only by the second optical fiber 20 as described above, the stress concentration is suppressed when the composite cable 1 is bent. Since the optical signal is transmitted only by the two optical fibers, the deterioration of the optical signal can be further suppressed. Further, since the second optical fiber 20 is spirally wound around the first optical fiber 10, the second optical fiber 20 has different lengths with respect to a certain length of the composite cable 1. Therefore, by using the first optical fiber 10 as a dummy fiber and transmitting the optical signal only by the second optical fiber, it is possible to prevent the transmission time of the optical signal from being different.

  Further, as described above, the pitch at which the electric wire 50 is wound is smaller than the pitch at which the second optical fiber 20 is helically wound, that is, the pitch at which the second optical fiber 20 is helically wound is the helical pitch of the electric wire 50. It can suppress that the curvature of a 2nd optical fiber becomes high by being larger than the pitch wound by a shape. Therefore, deterioration due to bending loss of the optical signal transmitted by the second optical fiber 20 can be suppressed. Moreover, since the electric wire 50 arrange | positioned at the outer peripheral side of the composite cable 1 receives the influence by the bending of the composite cable 1 more strongly, the flexibility of the composite cable 1 is improved by winding this electric wire 50 with a small pitch. be able to.

  As mentioned above, although this invention was demonstrated to the example for embodiment, this invention is not limited to these.

  For example, in the above-described embodiment, the cores 11 and 21 and the claddings 12 and 22 of the first and second optical fibers 10 and 20 are made of glass. However, in the present invention, at least the first and second optical fibers are used. One may be a plastic optical fiber (POF).

  Further, the second optical fiber 20 may be wound as a single spiral on the outer peripheral surface of the first optical fiber 10, or the electric wire 50 may be wound as a spiral.

  Further, the coating layer 40 may be formed by spirally winding an insulating tape around the optical fiber bundle 30.

  ADVANTAGE OF THE INVENTION According to this invention, while having the outstanding flexibility, the composite cable which can suppress deterioration of the optical signal in the place bent is provided.

DESCRIPTION OF SYMBOLS 1 ... Composite cable 10 ... 1st optical fiber 11 ... Core 12 ... Cladding 13 ... Protective layer 20 ... 2nd optical fiber 21 ... Core 22 ... Cladding 23 * ..Protective layer 30 ... optical fiber bundle 40 ... covering layer 50 ... electric wire 51 ... conductive wire 52 ... insulating layer 60 ... tape 70 ... sheath

Claims (7)

An optical fiber bundle having a first optical fiber arranged linearly and at least one second optical fiber spirally wound around the first optical fiber;
At least one electric wire spirally wound around the optical fiber bundle;
A composite cable characterized by comprising:   The composite cable according to claim 1, further comprising a tape wound spirally around the electric wire so as to cover the optical fiber bundle and the electric wire. A coating layer for coating the optical fiber bundle;
The composite cable according to claim 1, wherein the electric wire is spirally wound around the optical fiber bundle through the coating layer. The first optical fiber and the second optical fiber have the same diameter;
The composite cable according to claim 1, wherein the number of the second optical fibers is six.   The composite cable according to claim 1, wherein the first optical fiber is a dummy fiber that does not transmit an optical signal.   The composite cable according to any one of claims 1 to 5, wherein a pitch at which the second optical fiber is spirally wound is larger than a pitch at which the electric wire is spirally wound.   The composite cable according to claim 1, wherein the first optical fiber and the second optical fiber are optical fibers having a glass core and a clad.

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