JP2009265394A - Optical fiber cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical fiber cable which is prevented from being damaged when sticking a cicada's ovipositor, has no curl, and has flame resistance. <P>SOLUTION: The optical cable fiber has a coated optical fiber 13 and a tension member 14 disposed in parallel and coated integrally with a casing 15. The casing 15 has an inner first coating layer 15a covering an outer circumference of the coated optical fiber 13, and an outer second coating layer 15b covering an outer circumference of the first coating layer. The first coating layer 15a is formed of a resin material having a hardness of not less than 52 measured by a durometer (type D) and the second coating layer 15b is formed of a resin material having a smaller hardness than the first coating layer. The hardness of the first coating layer 15a may be 56 to 64 and the hardness of the second coating layer 15b may be not larger than 52. Further, the cross section ratio of the first coating layer 15a to the casing 15 is preferably 1/4 to 2/3. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical fiber cable in which an optical fiber core wire and a tension member are arranged in parallel and are integrally covered with a jacket.

  With the spread of information communication and the like such as the Internet, construction of an optical network is progressing in order to cope with bidirectional communication and large-capacity communication in addition to increasing the communication speed and the amount of information. In this optical network, a FTTH (Fiber To The Home) service has been started to provide a high-speed communication service by directly connecting a communication carrier and each home with an optical fiber. As a result, there is an increasing demand for drop optical cables that are used for drawing optical cables into the home, and aggregate optical cables in which a plurality of optical cables are aggregated. These optical fiber cables generally have a structure in which a tensile body is embedded in the cable jacket in parallel with the optical fiber core wire to increase the tensile strength of the cable.

  In recent years, a problem has frequently arisen with this type of optical fiber cable in that a spear pierces an egg laying tube into the cable jacket and damages the inner optical fiber core or lays an egg in the jacket. This is presumed that the drop optical cable was recognized as an object that the cocoon is likely to lay. However, as a measure against this cocoon, for example, as disclosed in Patent Documents 1 and 2, an internal optical fiber core wire is used. An optical fiber cable for preventing wrinkles is known in which a wire is surrounded by a hard protective body such as metal.

  As a conventional optical fiber cable for preventing wrinkles, for example, a self-supporting optical fiber in which a main body portion 8 and a support wire portion 9 as shown in FIGS. 4 (A) to 4 (C) are connected by a narrow neck portion. Cable is known. The main body 8 of the optical fiber cable 1a shown in FIG. 4A is provided with a tensile member 3 (also called a tension member) on both sides of the optical fiber core wire 2, and an optical fiber on both sides where the tensile member 3 is not arranged. This is an example in which a protective body 4 for wrinkle countermeasures is arranged across the core wire 2 and covered with a jacket 6 at once. In addition, a notch 7 for tearing the jacket is formed on the surface of the jacket 6 on which the protective body 4 is arranged.

  In the main body 8 of the optical fiber cable 1b shown in FIG. 4B, the tensile body 3 is disposed on both sides of the optical fiber ribbon 2 ', and the optical fiber tape core is disposed on both sides where the tensile body 3 is not disposed. In this example, a protection body 4 for wrinkle countermeasures is arranged across 2 ′ and covered with a jacket 6 at once. In addition, although the example in which the notch 7 for cutting the jacket is not formed is shown, the notch 7 may be formed.

The body portion 8 of the optical fiber cable 1c shown in FIG. 4C is provided with a tensile strength body 3 on both sides of the optical fiber core wire 2 and is made of a hard resin so that the spawning tube of the spider is not pierced. This is an example in which the cover is collectively covered with '. Further, the notch 7 for tearing the jacket may or may not be the same as described above.
4A to 4C, the main body portion 8 can be used separately from the support wire portion 9, and the support wire portion 9 is not provided from the beginning. It may be a thing.
JP 2006-11166 A JP 2006-195109 A

As shown in FIGS. 4A and 4B, the optical fiber cable having a structure in which the optical fiber core wire is protected by the protective body 4 is obtained by cutting the protective body when attaching the optical connector to the cable end. The workability is not good.
In addition, with the expansion of the application environment of optical fiber cables, optical cables to which non-halogen flame retardancy is imparted are required. However, when a hard resin material is used for the jacket as in the cable shown in FIG. 4C, there is a problem that it becomes difficult to add a flame retardant, and sufficient flame retardant characteristics cannot be realized. Furthermore, the hard jacket has a problem in that workability is not good due to the influence of curl when separated from the support wire.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to provide an optical fiber cable that prevents damage caused by piercing by a spawning tube of sputum, has flame retardancy, and has no curl.

An optical fiber cable according to the present invention is an optical fiber cable in which an optical fiber core wire and a tension member are arranged in parallel and is integrally covered with an outer cover, and the outer cover is a first inner wire covering the outer periphery of the optical fiber core wire. A coating layer and an outer second coating layer covering the outer periphery of the first coating layer, the first coating layer having a durometer (type D) hardness of 52 or more, and the second coating layer Is formed of a resin material having a hardness lower than that of the first coating layer.
For example, the hardness of the first coating layer can be 56 to 64, and the hardness of the second coating layer can be 52 or less. Moreover, it is desirable that the cross-sectional area ratio of the first covering layer to the outer jacket is 1/4 to 2/3. Note that a flame-retardant polyethylene resin can be used for the second coating layer.

  According to the present invention, the first covering layer of the outer cover has the drought resistance of preventing damage due to piercing by the spawning tube of the spider, the second covering layer gives the cable flame retardancy, The workability can be improved with less.

  An embodiment of the present invention will be described with reference to FIG. FIG. 1 (A) shows a basic form of an optical fiber cable according to the present invention, FIG. 1 (B) shows an example having a notch, and FIG. 1 (C) shows an optical fiber core without a support line and a first covering layer. An example of covering only a line is shown, and FIG. 1D is a diagram showing an example having a notch without a support line. In the figure, 10a to 10d are optical fiber cables, 11 is a main body part, 12 is a support line part, 13 is an optical fiber core wire, 14 is a tension member, 15 is a jacket, 15a is a first covering layer, and 15b is a first coating layer. 2 coating layers, 16 a notch, 17 a steel wire, and 18 a neck.

  In the optical fiber cable 10a shown in FIG. 1A, a main body portion 11 and a support wire portion 12 are integrally formed through a narrow neck portion 18. The main body 11 is formed by, for example, arranging tension members (also referred to as strength members) 14 on both sides of the optical fiber core wire 13 and integrally covering with a jacket 15. The support wire portion 12 is a steel wire 17 (outer diameter of about 1.2 mm) made of a single core wire or a stranded wire, and is covered with the same resin material as the outer cover 15 when the outer cover 15 of the main body 11 is molded. Formed. This form of cable is often used as a drop cable.

The optical fiber core wire 13 is referred to as an optical fiber strand in which a glass fiber having a standard outer diameter of 125 μm is coated with a coating outer diameter of about 250 μm, and further, a coating is applied to the outside or a colored coating is applied. It shall include all applied. One to several optical fiber cores are used.
For the tension member 14, a wire having a resistance to tension and compression can be used. For example, steel wire with an outer diameter of 0.4 mm to 0.7 mm, glass fiber reinforced plastic (G-FRP), aramid fiber reinforced plastic (K-FRP), etc. are used for a long period of time in a high to low temperature environment. Can withstand.

  The outer jacket 15 is formed of two layers including an inner first covering layer 15a that directly covers the optical fiber core wire 13 and a second covering layer 15b that covers the outer periphery of the first covering layer 15a. The inner first covering layer 15a is formed of a hard resin material that is hard to pierce the spawning tube of the cocoon. For example, the hardness by the durometer (type D) hardness test method defined by JIS K 7215 is 52 or more. The resin material is used. The second coating layer 15b is formed of a resin material that has a lower hardness than the first coating layer 15a and has flame retardancy. In the optical fiber cable 10a, for example, the main body portion 11 has a long side of 3.1 ± 0.2 mm, the short side has a length of 2.0 ± 0.2 mm, and the support wire portion 12 has a coated outer diameter of 2.8 ± 0. It is formed with an external dimension of 2 mm.

  The optical fiber cable 10b shown in FIG. 1 (B) is formed integrally with the main body 11 and the support wire portion 12 via the narrow neck portion 18 in the same manner as in the example of FIG. 1 (A). This is an example in which a notch 16 for facilitating the removal of the optical fiber core wire is provided. The notches 16 are formed on both side surfaces of the outer jacket 15 on the side where the tension member 14 is not disposed, for example, at positions that coincide with the optical fiber core wire 13.

  As in the example of FIG. 1A, the jacket 15 of the optical fiber cable 10b includes an inner first covering layer 15a and a second covering layer 15b covering the outer periphery of the first covering layer 15a. Formed by two layers. The inner first covering layer 15a is formed of a hard resin material that is hard to be pierced by the spawning tube, and the second covering layer 15b is less hard than the first covering layer 15a and has flame retardancy. It is made of resin material. The spider laying tube is often pierced from the portion of the notch 16 having a small distance to the optical fiber core wire 13, but can be blocked by the hard first covering layer 15a.

  An optical fiber cable 10c shown in FIG. 1C is a cable that does not have a support wire portion or has been removed. This type of cable is often used as an aggregate cable that is laid as a branch line by assembling a plurality of cables, or as an indoor cable used for indoor wiring. The optical fiber cable 10c is the same as the main body 11 in FIG. 1A in the configuration in which the tension members 14 are arranged on both sides of the optical fiber core wire 13.

  As in the example of FIG. 1A, the outer jacket 15 of the optical fiber cable 10c includes an inner first coating layer 15a and a second coating layer 15b covering the outer periphery of the first coating layer 15a. Formed by two layers. The inner first covering layer 15a is formed of a hard resin material that is hard to be pierced by the spawning tube, and the second covering layer 15b is less hard than the first covering layer 15a and has flame retardancy. It is made of resin material. The first coating layer 15 a covers the outer periphery of the optical fiber core wire 13 but does not cover the tension member 14. The tension member 14 is covered with the second covering layer 15b. In other words, the first coating layer 15a only needs to cover at least the outer periphery of the optical fiber core wire 13, thereby avoiding direct damage due to the spawning tube of the spider. In this example, since the ratio of the second coating layer 15b is increased as compared with the example of FIG. 1A, the flame retardancy is improved and the curl is reduced accordingly.

  An optical fiber cable 10d shown in FIG. 1D is an example in which a support line portion is not provided or removed, and a notch is provided. As in the case of FIG. 1C, this form of cable is used as a collective cable that assembles a plurality of cables as a branch line or an indoor cable used for indoor wiring. The optical fiber cable 10d has a configuration in which tension members 14 are arranged on both sides of an optical fiber core wire 13 and is formed of two layers including a hard first coating layer 15a and a flame retardant second coating layer 15b. Is the same as the main body 11 in FIG. Even when the spider laying tube pierces from the portion of the notch 16 having a small distance to the optical fiber core wire 13, it can be blocked by the hard first covering layer 15a.

  FIG. 2 is a diagram showing an example in which an optical fiber core wire (hereinafter referred to as a “tape core wire”) in which a plurality of optical fibers are arranged and collectively covered is used as the optical fiber core wire. FIG. 1A shows a basic form, FIG. 1B shows an example having a notch, and FIG. 1C shows an example in which the first covering layer covers only the tape core without a support line. FIG. 1D is a diagram showing an example having a notch without a support line. In the figure, 20a to 20d are optical fiber cables, and 13 'is a tape core. Other parts having the same functions as those described with reference to FIG.

  In the optical fiber cable 20a shown in FIG. 2A, the main body portion 11 and the support wire portion 12 are integrally formed via a narrow neck portion 18. The main body 11 uses a four-core fiber core 13 ′ as an optical fiber core, and arranges tension members 14 on both sides in the width direction so as to be aligned with the tape core 13 ′. It is integrally coated. The support wire portion 12 is a steel wire 17 (outer diameter of about 1.2 mm) made of a single core wire or a stranded wire, and is covered with the same resin material as the outer cover 15 when the outer cover 15 of the main body 11 is molded. Formed. This form of cable is often used as a drop cable.

  The tape core wire 13 'is formed by coating a plurality of optical fiber core wires in which a glass fiber having a standard outer diameter of 125 μm and a coating outer diameter of about 250 μm are arranged in a row, for example, four cores and having a width. The one having a thickness of about 1.1 mm and a thickness of about 0.3 mm is used. One to several tape cores 13 'are used. As the tension member 14, a wire material having a resistance to tension and compression can be used as described in the example of FIG. 1, and detailed description thereof is omitted.

  Similarly to the outer cover 15, as described in the example of FIG. 1, the inner first covering layer 15a that directly covers the tape core wire 13 'and the second outer covering that covers the outer periphery of the first covering layer 15a. The cover layer 15b is formed of two layers. The inner first covering layer 15a is made of a hard resin material that is hard to be pierced by the spawning tube of the cocoon, and is made of a resin material having a durometer (type D) hardness of 52 or more. The second coating layer 15b is formed of a resin material that has a lower hardness than the first coating layer 15a and has flame retardancy. In the optical fiber cable 20a, for example, the main body portion 11 has a long side of 3.7 ± 0.2 mm, the short side has a length of 2.0 ± 0.2 mm, and the support wire portion 12 has a coated outer diameter of 2.8 ± 0. It is formed with an external dimension of 2 mm.

The optical fiber cable 20b shown in FIG. 2 (B) is formed by integrally forming the main body portion 11 and the support wire portion 12 through the narrow neck portion 18 as in the example of FIG. 2 (A). This is an example in which a notch 16 for accommodating the wire 13 ′ and facilitating removal of the optical fiber core wire by forming a cable end or the like is provided. The notches 16 are formed on both side surfaces of the outer jacket 15 on the side where the tension member 14 is not disposed, for example, at positions that coincide with the tape core wire 13 ′.
As in the example of FIG. 2A, the outer jacket 15 of the optical fiber cable 20b includes an inner hard first covering layer 15a and a flame-retardant second covering the outer periphery of the first covering layer 15a. The shape and function are the same as in the example of FIG. 1B.

  The optical fiber cable 20c shown in FIG. 2C is a cable that does not have a support line portion or has been removed. This type of cable is often used as an aggregate cable that is laid as a branch line by assembling a plurality of cables, or as an indoor cable used for indoor wiring. The optical fiber cable 20c is the same as the main body 11 in FIG. 2A in the configuration in which the tension members 14 are arranged on both sides of the tape core wire 13 '.

  As in the example of FIG. 2A, the jacket 15 of the optical fiber cable 20c includes an inner first covering layer 15a and a second covering layer 15b covering the outer periphery of the first covering layer 15a. Formed in two layers. However, the first coating layer 15a covers the outer periphery of the optical fiber core wire 15a, but does not cover the tension member 14. The tension member 14 is different in that it is covered with the second covering layer 15b. That is, as in the example of FIG. 1 (C), the first covering layer 15a only needs to cover at least the outer periphery of the tape core wire 13 ', thereby avoiding direct damage by the spawning tube of the salmon. Can do. In this example, since the ratio of the second coating layer 15b is increased as compared with the example of FIG. 2A, the flame retardancy is improved and the curl is reduced accordingly.

  An optical fiber cable 20d shown in FIG. 2D is an example in which a support line portion is not provided or removed, and a notch is provided. As in the case of FIG. 2C, this form of cable is used as an aggregate cable that is assembled as a branch line by assembling a plurality of cables, or as an indoor cable used for indoor wiring. The optical fiber cable 20d is formed of two layers including a hard first coating layer 15a and a flame-retardant second coating layer 15b, with tension members 14 disposed on both sides of the tape core wire 13 '. Configured.

  In the optical fiber cable according to the present invention, as described above, the jacket 15 covers at least the outer periphery of the optical fiber core wire 13 (including the tape core wire 13 ') with the hard first covering layer 15a, thereby Prevent damage from laying tube piercing. In this case, the first coating layer 15a needs to have a hardness that does not allow the spawning tube to pierce. If the hardness of the first covering layer 15a is 52 or more by durometer (type D), the spawning tube can be prevented from being pierced by a durometer. .

  And the outer periphery of the 1st coating layer 15a is covered with the 2nd coating layer 15b, and the predetermined coating thickness and the shape of the jacket 15 are ensured as the whole jacket. The second coating layer 15b is formed of a softer resin material than the first coating layer 15a. Thereby, bending wrinkles due to the outer jacket 15 can be reduced, and handleability can be improved. Further, by using a soft resin material for the second coating layer 15b, it is possible to add a flame retardant and to realize a flame retardant cable. The first coating layer 15a and the second coating layer 15b can be easily formed by using a two-color extrusion molding machine.

  FIG. 3 shows the evaluation results of the optical fiber cable according to the present invention, and FIG. 3 (A) compares the characteristics with the conventional optical fiber cable. The test product (A) corresponds to the conventional cable shown in FIG. 4 (A), in which the hardness of the entire jacket is 48 (soft) and protective bodies are arranged on both sides of the optical fiber core. . The test product (b) corresponds to the conventional cable shown in FIG. 4 (C), in which the entire jacket has a hardness of 60 (hard) and no protective body is provided on both sides of the optical fiber core. . The test article (C) corresponds to the cable shown in FIG. 1A of the present invention, and the hardness of the inner first coating layer is 60, and the hardness of the outer second coating layer is 482. It is formed with a layered outer coat. The outer jacket was made of flame-retardant polyethylene and had a rectangular cross section of 2.0 mm × 3.1 mm.

  As for the evaluation item (1), bending of the main body part, the test products (a) and (c) were not particularly problematic, but the test product (b) was bent to Φ100 mm or less when the support wire was cut and separated. Habit occurred. As for the evaluation item (2) flame retardancy, the test products (b) and (c) were able to clear the flame retardancy test of JISC3521, but the test product (b) was flame retardant of the jacket. However, the fire retardant test could not be cleared.

  With regard to the evaluation item (3) handling properties, the test products (b) and (c) had no particular problems, but the test product (b) required removal of the protective body. As for the evaluation item (4), the test product (b) is a protective body, the test product (b) is a hard jacket, and the test product (c) is a hard first covering layer. It was also possible to protect the optical fiber core from the laying tube piercing of the spider.

  3 (B) and 3 (C) are optical fiber cables according to the present invention, with respect to the cross-sectional area ratio between the inner first coating layer and the outer second coating layer, and the relationship between the respective hardnesses. It is a figure which shows the evaluation result from a viewpoint of a bending wrinkle. The hardness of the coating layer indicates a value obtained by a test using a durometer (type D) defined in JIS K7215. “○” indicates that no bending wrinkles occur in the main body after the support line is removed, “△” indicates that bending wrinkles of Φ100 mm or more occur in the main body, and “×” indicates that bending wrinkles less than Φ100 mm occur in the main body. The case where it occurred is shown.

  FIG. 3B shows the case where the cross-sectional area of the first covering layer is “3” and the cross-sectional area of the second covering layer is “1”, that is, the cross-sectional area of the first covering layer is the entire outer cover. Of 3/4 (75%). The hardness of the first coating layer is 52 to 56 and the hardness of the second coating layer is “Δ” in the range of 40 to 44, but above that, a bending wrinkle less than Φ100 mm occurs. This indicates that when the hard first covering layer occupies 75% of the entire outer cover in the cross-sectional area, the hard covering layer becomes dominant and bending wrinkles are likely to occur.

  FIG. 3C shows the case where the cross-sectional area of the first covering layer is “2” and the cross-sectional area of the second covering layer is “1”, that is, the cross-sectional area of the first covering layer is the entire outer cover. Of 2/3 (67%). The hardness of the first coating layer is 52 to 64, and the hardness of the second coating layer is “◯” in the range of 52 or less. In addition, when the hardness of the 1st coating layer is 52 or less, there exists damage by a spawning tube of a cocoon, and is not evaluated.

  From the evaluation results shown in FIGS. 3B and 3C, it is desirable that the hard first coating layer has a cross-sectional area of 67% or less of the entire outer cover. Further, the hard first coating layer needs to cover at least the outer periphery of the optical fiber core wire, and the hard first coating layer has a cross-sectional area of 1/4 (25%) or more of the entire jacket. It is desirable to do. In this case, from the result of FIG. 3C, in order to completely eliminate the bending wrinkles, the hardness of the first coating layer is set to 56 to 64, and the hardness of the second coating layer is set to 52 or less. Is desirable.

It is a figure explaining embodiment of this invention. It is a figure explaining other embodiment of this invention. It is a figure which shows the evaluation result of this invention. It is a figure explaining a prior art.

Explanation of symbols

10a to 10d, 20a to 20d ... optical fiber cable, 11 ... main body, 12 ... support wire part, 13 (13 ') ... optical fiber core wire (tape core wire), 14 ... tension member, 15 ... jacket, 15a ... 1st coating layer, 15b ... 2nd coating layer, 16 ... Notch, 17 ... Steel wire, 18 ... Neck part.

Claims (4)

An optical fiber cable in which an optical fiber core wire and a tension member are arranged in parallel and are integrally covered with a jacket,
The jacket includes an inner first covering layer that covers the outer periphery of the optical fiber core wire, and an outer second covering layer that covers the outer periphery of the first covering layer, and the first covering layer Is a durometer (type D) having a hardness of 52 or more, and the second coating layer is formed of a resin material whose hardness is smaller than that of the first coating layer.   2. The optical fiber cable according to claim 1, wherein the first covering layer has a hardness of 56 to 64, and the second covering layer has a hardness of 52 or less.   3. The optical fiber cable according to claim 1, wherein a cross-sectional area ratio of the first covering layer to the outer jacket is ¼ to 2/3.   The optical fiber cable according to any one of claims 1 to 3, wherein the second coating layer is a flame retardant polyethylene resin.

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