Optical cable

Abstract

To provide an optical cable 1 which allows use of coaxial cable terminal processing equipment.SOLUTION: An optical cable 1 is provided, comprising a first insulating coating layer 20 concentrically covering an outer surface of an optical fiber 10 with respect to the optical fiber 10, a braided wire 30 braided with multiple strands and configured to concentrically cover an outer surface of the first insulating coating layer 20 with respect to the optical fiber 10, and a second insulating coating layer 40 configured to concentrically cover an outer surface of the braided wire 30 with respect to the optical fiber 10.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an optical cable. [Background technology]

[0002] Optical fiber cables are widely used in information communications because they are suitable for high-speed communications and have excellent EMC resistance. When optical fiber is used in automobiles, etc., there is a risk that the optical fiber will be subjected to strong forces, so optical fiber cables are required to have high wire tensile strength.

[0003] Patent Document 1 discloses an optical cable in which an optical fiber core is covered with a sheath material, the sheath material being made of a material containing polyphenylene ether. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-2910 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the optical fiber described in Patent Document 1 has a different structure from conventional high-speed electrical communication lines. Therefore, a dedicated terminal processing machine must be prepared, which may increase the cost of capital investment.

[0006] The present invention has been made in view of the problems inherent in the prior art, and an object of the present invention is to provide an optical cable that is highly versatile and can be manufactured using the same terminal processing equipment as coaxial cables. [Means for solving the problem]

[0007] An optical cable according to an aspect of the present invention includes an optical fiber and a first insulating coating layer that concentrically covers the outer surface of the optical fiber. The optical cable includes a braided wire formed by braiding multiple strands, with the outer surface of the first insulating coating layer concentrically covering the optical fiber. The optical cable includes a second insulating coating layer that concentrically covers the outer surface of the braided wire with the optical fiber. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an optical cable that is highly versatile and can utilize terminal processing equipment for coaxial cables. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a side view showing an optical cable according to an embodiment; [Figure 2] 1 is a cross-sectional view showing an optical cable according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] The optical cable, the optical cable with terminal, and the method for manufacturing the optical cable according to the present embodiment will be described in detail below with reference to the drawings. Note that the dimensional proportions in the drawings are exaggerated for the convenience of explanation and may differ from the actual proportions.

[0011] [Optical cable] FIG. 1 is a side view showing an optical cable 1 according to one embodiment. FIG. 2 is a cross-sectional view showing the optical cable 1 according to one embodiment. As shown in FIGS. 1 and 2, the optical cable 1 includes an optical fiber 10, a first insulating coating layer 20, a braided wire 30, and a second insulating coating layer 40. The optical cable 1 according to this embodiment is a cable that propagates light. As shown in FIG. 2, the optical fiber 10 has a circular shape when viewed from an axial direction perpendicular to a plane cut in the radial direction.

[0012] As shown in Figure 2, the optical fiber 10 has a circular shape when viewed in the axial direction. The optical fiber 10 includes a core and a cladding that has a lower refractive index than the core and that concentrically covers the outer periphery of the core. The core is a transmission path for transmitting optical signals. The cladding also serves to reflect light from the outer periphery of the core and confine the light within the core. By including a core and a cladding, the optical fiber 10 can transmit light to distant locations.

[0013] The optical fiber 10 is made of at least one of glass and plastic. For example, the optical fiber 10 may be a glass optical fiber in which both the core and cladding are made of glass. Alternatively, the optical fiber 10 may be a plastic optical fiber (POF) in which both the core and cladding are made of plastic. The optical fiber 10 may have a core made of glass and a cladding made of plastic.

[0014] The glass used in the optical fiber 10 may be quartz glass. The plastic used in the optical fiber 10 may be a synthetic resin such as an acrylic resin such as polymethyl methacrylate (PMMA), polycarbonate (PC), or a fluororesin. From the viewpoint of optical transparency, the core may be an acrylic resin. Also, from the viewpoint of heat resistance, the core may be polycarbonate. The cladding may be a fluororesin. The fluororesin may be a fluorinated acrylate resin, a vinylidene fluoride resin, a tetrafluoroethylene resin, or a mixture thereof.

[0015] The first insulating coating layer 20 coats the outer peripheral surface of the optical fiber 10 concentrically with respect to the optical fiber 10. The first insulating coating layer 20 has a cylindrical shape, and has an annular shape when viewed in the axial direction as shown in FIG.

[0016] The thickness of the first insulating coating layer 20 may be 0.2 mm or more and 4 mm or less, as specified in JIS C3501-1993 (High Frequency Coaxial Cable (Polyethylene Insulated Braided)). The thickness of the first insulating coating layer 20 may be 0.4 mm or more, 0.6 mm or more, 0.8 mm or more, or 1 mm or more. The thickness of the first insulating coating layer 20 may be 3 mm or less, 2 mm or less, or 1 mm or less.

[0017] The outer diameter of the first insulating coating layer 20 may be 0.8 mm or more and 10 mm or less, as specified in JIS C3501-1993 (High Frequency Coaxial Cable (Polyethylene Insulated Braided)). The outer diameter of the first insulating coating layer 20 may be 1 mm or more, 2 mm or more, 3 mm or more, or 4 mm or more. The outer diameter of the first insulating coating layer 20 may be 10 mm or less, 9 mm or less, 8 mm or less, or 7 mm or less.

[0018] The first insulating coating layer 20 may contain an insulating resin such as polyolefin. Polyolefin is also used in the insulating coating layer that covers the outer periphery of the central conductor of a coaxial cable, and the optical cable 1 according to this embodiment can be easily processed using terminal processing equipment for coaxial cables. The polyolefin may contain at least one selected from the group consisting of polyethylene, polypropylene, ethylene-ethyl acrylate copolymer, ethylene-methyl acrylate copolymer, and ethylene-vinyl acetate copolymer. The resin of the first insulating coating layer 20 may be crosslinked. Specifically, the polyolefin of the first insulating coating layer 20 may contain a crosslinked polyolefin.

[0019] The first insulating coating layer 20 may contain a filler, for example to improve strength, and may also contain various additives such as antioxidants, lubricants, metal deactivators, pigments, and fillers. The first insulating coating layer 20 may be foamed or non-foamed polyolefin.

[0020] The tensile strength of the first insulating coating layer 20 may be 10 MPa or more, as specified in JIS C3501-1993 (High-frequency coaxial cable (polyethylene insulated braided type)). Such a configuration ensures the mechanical strength of the optical cable 1. The tensile strength of the first insulating coating layer 20 can be measured in accordance with JIS C3005:2014. The tensile strength of the first insulating coating layer 20 may be 50 MPa or less, 40 MPa or less, 30 MPa or less, or 20 MPa or less.

[0021] The elongation of the first insulating coating layer 20 may be 400% or more, as specified in JIS C3501-1993 (High-frequency coaxial cable (polyethylene insulated braided type)). Such a configuration ensures the mechanical strength of the optical cable 1. The elongation of the first insulating coating layer 20 can be measured in accordance with JIS C3005:2014. The elongation of the first insulating coating layer 20 may be 10,000% or less, 5,000% or less, 1,000% or less, or 500% or less.

[0022] The braided wire 30 covers the outer peripheral surface of the first insulating coating layer 20 concentrically around the optical fiber 10. The braided wire 30 is made of a plurality of metal wires braided together. By configuring the optical cable 1 in this manner similar to a coaxial cable, the wire tensile strength of the optical fiber 10 can be ensured. The braided wire 30 may have a plurality of wires arranged concentrically at equal intervals. The braided wire 30 is cylindrical and has a circular ring shape when viewed in the axial direction as shown in FIG. 2.

[0023] The element wires of the braided wire 30 are made of metal. The element wires of the braided wire 30 may contain aluminum, copper, or an alloy thereof. Examples of copper or copper alloy element wires include hard copper wire, semi-hard copper wire, annealed copper wire, copper-silver alloy wire, copper-zinc alloy wire, copper-tin alloy wire, beryllium copper wire, titanium copper wire, zirconium copper wire, iron-reinforced copper wire, and Corson alloy wire.

[0024] The thickness of the braided wire 30 may be 0.5 mm or more and 1 mm or less. The thickness of the braided wire 30 may be 0.6 mm or more, 0.7 mm or more, 0.8 mm or more, or 0.9 mm or more. The thickness of the braided wire 30 may be 0.9 mm or less, 0.8 mm or less, 0.7 mm or less, or 0.6 mm or less. The diameter of the strands of the braided wire 30 may be 0.10 mm to 0.20 mm.

[0025] The second insulating coating layer 40 covers the outer peripheral surface of the braided wire 30 concentrically with the optical fiber 10. The second insulating coating layer 40 has a cylindrical shape and has a circular ring shape when viewed from the axial direction as shown in Fig. 2. The second insulating coating layer 40 is disposed on the outermost side of the optical cable 1 in the radial direction.

[0026] The thickness of the second insulating coating layer 40 may be 0.35 mm or more and 1.3 mm or less, as specified in JIS C3501-1993 (High Frequency Coaxial Cable (Polyethylene Insulated Braided)). The thickness of the second insulating coating layer 40 may be 0.4 mm or more, 0.5 mm or more, 0.6 mm or more, 0.7 mm or more, 0.8 mm or more, or 0.9 mm or more. The thickness of the second insulating coating layer 40 may be 1.2 mm or less, 1.1 mm or less, 1 mm or less, 0.9 mm or less, or 0.8 mm or less.

[0027] The outer diameter of the second insulating coating layer 40 may be 2 mm or more and 15 mm or less, as specified in JIS C3501-1993 (High Frequency Coaxial Cable (Polyethylene Insulated Braided)). The outer diameter of the second insulating coating layer 40 may be 3 mm or more, 4 mm or more, 5 mm or more, 6 mm or more, 7 mm or more, or 8 mm or more. The outer diameter of the second insulating coating layer 40 may be 14 mm or less, 13 mm or less, 12 mm or less, or 11 mm or less.

[0028] The second insulating coating layer 40 may contain at least one thermoplastic resin having insulating properties, for example, selected from the group consisting of polyvinyl chloride (PVC) and polyolefin. Such a configuration can improve the flexibility of the optical cable 1. The polyolefin may contain at least one selected from the group consisting of polyethylene, polypropylene, ethylene-ethyl acrylate copolymer, ethylene-methyl acrylate copolymer, and ethylene-vinyl acetate copolymer. The resin of the second insulating coating layer 40 may be crosslinked. Specifically, the polyolefin of the second insulating coating layer 40 may contain a crosslinked polyolefin.

[0029] The tensile strength of the second insulating coating layer 40 may be 10 MPa or more, as specified in JIS C3501-1993 (High-frequency coaxial cable (polyethylene insulated braided type)). Such a configuration ensures the mechanical strength of the optical cable 1. The tensile strength of the second insulating coating layer 40 can be measured in accordance with JIS C3005:2014. The tensile strength of the second insulating coating layer 40 may be 50 MPa or less, 40 MPa or less, 30 MPa or less, or 20 MPa or less.

[0030] The elongation of the second insulating coating layer 40 may be 200% or more, as specified in JIS C3501-1993 (High-frequency coaxial cable (polyethylene insulated braided type)). Such a configuration ensures the mechanical strength of the optical cable 1. The elongation of the second insulating coating layer 40 can be measured in accordance with JIS C3005:2014. The elongation of the second insulating coating layer 40 may be 10,000% or less, 5,000% or less, 1,000% or less, or 500% or less.

[0031] The optical fiber 10 may be a multimode optical fiber or a single-mode optical fiber. The optical fiber 10 may be a graded-index fiber, a pseudo-step-index fiber, or a step-index fiber. The optical fiber 10 may also be a single-clad fiber including one cladding layer or a double-clad fiber including two cladding layers.

[0032] The optical cable 1 may be used as an optical cable for a wire harness. The wire harness may include, for example, a plurality of optical cables 1, or may be configured by bundling a plurality of optical cables 1. The wire harness may include at least one electric wire including a conductor and an insulating coating layer that covers the conductor.

[0033] As described above, the optical cable 1 according to this embodiment includes the optical fiber 10 and the first insulating coating layer 20 that concentrically covers the outer peripheral surface of the optical fiber 10. The optical cable 1 includes the braided wire 30 in which a plurality of wires are braided, with the outer peripheral surface of the first insulating coating layer 20 concentrically covering the optical fiber 10. The optical cable 1 includes the second insulating coating layer 40 that concentrically covers the outer peripheral surface of the braided wire 30 with the optical fiber 10.

[0034] The optical cable 1 according to this embodiment has a similar configuration to a coaxial cable. This makes it highly versatile and allows the use of terminal processing equipment for coaxial cables. This reduces capital investment at production bases and facilitates the repurposing of production technology. Furthermore, because the structure is similar to that of coaxial cables that have a proven track record in automotive applications, the design concept of existing coaxial cables can be used for vehicle installation design, making it easier to ensure performance. Furthermore, because the structure is similar to that of coaxial cables, connectors with a similar configuration to coaxial cable connectors that have a proven track record in automotive applications can be attached during terminal processing.

[0035] The wires may be made of metal. A braided wire 30 made of such wires can improve the tensile strength of the optical cable 1. Furthermore, compared to aramid fibers such as Kevlar (registered trademark) used in general optical cables, metal wires such as those used in coaxial cables are easier to cut with a termination processing machine. This reduces wear on the cutting blade and shortens the time required for termination processing. Furthermore, unlike coaxial cables, the optical cable 1 has an optical fiber 10, rather than a conductor, located in the center. Therefore, even if there is a defect in the termination processing of the braided wire 30, defects such as short circuits that occur with coaxial cables do not occur, and therefore such an inspection process can be omitted.

[0036] The first insulating coating layer 20 may contain polyolefin. Such a configuration is closer to that of a coaxial cable, making it easier to process in terminal processing equipment for coaxial cables. Furthermore, the first insulating coating layer 20 as described above can effectively protect the optical fiber 10. Furthermore, since polyolefin has high flexibility, the optical cable 1 can be more flexible, improving its handling when mounted on a vehicle, for example.

[0037] [Optical cable with terminal] Next, an optical cable with terminal according to this embodiment will be described. The cable with terminal according to this embodiment may include an optical cable 1 and a crimp connector (not shown) attached to the end of the optical cable 1. The crimp connector allows the optical cable 1 to be electrically connected to other components. As described above, the optical cable 1 can utilize the same terminal processing equipment used for coaxial cables, so even when a crimp connector is attached to the optical cable 1 by crimping, deformation and breakage of the optical fiber 10 can be suppressed.

[0038] The crimp connector is attached to the end of the optical cable 1. The connector may include a crimping portion that crimps the second insulating coating layer 40 of the optical cable 1 and a connecting portion for mechanically connecting to a mating member (not shown). The connector can be attached to the optical cable 1 by attaching the crimping portion of the connector to the optical cable 1 by crimping or the like. The terminal portion of the optical cable 1 connected to the connector may have an exposed portion where the first insulating coating layer 20, the braided wire 30, and the second insulating coating layer 40 have been removed to expose the optical fiber 10.

[0039] [Optical cable manufacturing method] Next, a description will be given of a method for manufacturing the optical cable 1 according to this embodiment. The method for manufacturing the optical cable 1 according to this embodiment includes an optical fiber preparation step, a first insulating coating step, a braided wire formation step, and a second insulating coating step.

[0040] (Optical fiber preparation process) In the optical fiber preparation step, the optical fiber 10 is prepared. As described above, the optical fiber 10 includes a core and a cladding.

[0041] (First insulating coating process) In the first insulating coating step, the outer peripheral surface of the optical fiber 10 is extruded using an extruder to concentrically coat the optical fiber 10 with a molten first insulator, thereby forming the first insulating coating layer 20. The first insulator may be an insulating resin such as polyolefin.

[0042] (Knitting wire formation process) In the braided wire forming step, a braiding machine is used to braid a plurality of wires together, thereby concentrically covering the outer circumferential surface of the first insulating coating layer 20 around the optical fiber 10, thereby forming the braided wire 30.

[0043] (Second insulating coating process) In the second insulating coating step, the outer peripheral surface of the braided wire 30 is coated with a molten second insulator concentrically around the optical fiber 10 by extrusion molding using an extruder, thereby forming the second insulating coating layer 40. The second insulator may be at least one thermoplastic resin selected from the group consisting of polyvinyl chloride (PVC) and polyolefin.

[0044] The manufacturing method of the optical cable 1 may involve using a coaxial cable stripper to remove the first insulating coating layer 20, the braided wire 30, and the second insulating coating layer 40 from the end of the optical cable 1, thereby forming an exposed portion at the end of the optical cable 1 where the optical fiber 10 is exposed.

[0045] According to the manufacturing method of the optical cable 1 according to this embodiment, the optical cable 1 can be manufactured by the same manufacturing method as that for a coaxial cable.

[0046] Although the present embodiment has been described above, the present embodiment is not limited to this, and various modifications are possible within the scope of the gist of the present embodiment. [Explanation of symbols]

[0047] 1 optical cable 10 Optical Fiber 20 First insulating coating layer 30 braided wire 40 Second insulating coating layer

Claims

1. An optical fiber; a first insulating coating layer that coats the outer peripheral surface of the optical fiber concentrically with respect to the optical fiber; a braided wire in which a plurality of wires are braided together, the braided wire concentrically covering the outer peripheral surface of the first insulating coating layer around the optical fiber; a second insulating coating layer that covers the outer peripheral surface of the braided wire concentrically with the optical fiber; An optical cable comprising:

2. The optical cable according to claim 1 , wherein the wires are made of metal.

3. The optical cable according to claim 1 or 2, wherein the first insulating coating layer contains polyolefin.

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