JP2010039050A - Optical fiber cable - Google Patents

Abstract

An object of the present invention is to protect an optical fiber from a spawning tube of a spider and prevent a reduction in connection work.
One or more optical fibers arranged at the center and a straight line parallel to one of two directions orthogonal to the longitudinal direction of the optical fiber and passing through the center of the optical fiber. And a pair of strength members 5 extending on both sides of the optical fiber 3 in the longitudinal direction of the optical fiber 3 and a Shore D hardness integrally coated on the outer periphery of the optical fiber 3 and the pair of strength members 5. An optical fiber cable constituting a long optical element portion 9 composed of a first jacket 7 composed of 53 or less, parallel to the other of the two directions, and centered on the optical fiber 3 A second outer cover 11 having a Shore D hardness of 55 or more is formed from the upper and lower surfaces of the first outer cover 7 including a straight line to the inside of the first outer cover 7. 7 and the second jacket 11 are joined together to form a single piece. It is characterized in that is.
[Selection] Figure 1

Description

  The present invention relates to an optical fiber cable, and more particularly to an optical fiber drop cable or a small building or a general building constructed between utility poles when one or more optical fibers made of, for example, an optical fiber core are drawn into a small building or general home. The present invention relates to an optical fiber cable for drawing into a home.

  Conventionally, FTTH (Fiber to the Home), that is, from an optical fiber cable of an access system extended from a telephone office to a building or general in order to be able to transmit and receive high-speed broadband information such as ultra-high-speed data at home or office For example, an optical fiber made of an optical fiber core or the like is pulled down to a subscriber's house such as a house, and an optical fiber drop cable is used for wiring the optical fiber. In other words, the optical fiber drop cable is used when drawing the optical fiber from the branch closure of the main line cable on the utility pole into the home, and is mainly applied to the optical fiber drop cable (outdoor line) and a longer installation span. For this purpose, a small-core optical aerial cable with an increased support line size is used.

  As known in Patent Document 1 and Non-Patent Document 1, for example, referring to FIG. 3, as a conventional optical fiber drop cable 101, for example, one or more optical fiber cores arranged at the center, etc. And an optical fiber 103, and parallel to one direction (left and right direction in FIG. 3) of two directions orthogonal to the longitudinal direction of the optical fiber 103 (direction perpendicular to the paper surface in FIG. 3), and the light. A pair of strength members 105 made of, for example, an aramid fiber FRP and the like, which are extended in the longitudinal direction of the optical fiber 103 on both sides of the optical fiber 103 on a straight line passing through the center of the fiber 103, and the optical fiber 103 and a pair of tensile strength An outer cover 107 made of a resin such as a non-halogen flame retardant sheath, for example, having a rectangular cross-sectional shape covering the outer periphery of the body 105 It constitutes an element portion 109.

  In this optical element portion 109, a flat inclusion 111 is provided at a certain distance of the optical fiber 103 in the outer jacket 107 above and below the optical fiber 103.

  The long optical element portion 109 is integrated with a jacket 117 made of resin in which a support wire 115 made of, for example, steel wire is coated on the left side of the jacket 107 in the optical element portion 109 via a neck portion 113. The long optical fiber drop cable 101 is configured by the support line portion 119.

  The inclusion 111 is provided in the outer sheath 107 above and below the optical fiber 103 at a certain distance from the optical fiber 103, so that the bearfish stabs the egg-laying tube into the outer sheath 107, and light The occurrence of a failure that breaks the fiber 103 is prevented.

  Further, as the optical fiber drop cable 121 that takes measures against the damage of the oviposition of the bearfish, the one shown in FIG. 4 is used. In FIG. 4, as an optical fiber drop cable 121, for example, an optical fiber 103 composed of one or more optical fiber cores arranged at the center, and the longitudinal direction of this optical fiber 103 (in FIG. 4, orthogonal to the paper surface). For example, an aramid fiber FRP and the like, which is arranged to extend in the longitudinal direction of the optical fiber 103 on both sides of a straight line passing through the center of the optical fiber 103. A jacket 107 made of a high-strength resin having, for example, a rectangular cross-sectional shape and a low friction and wear resistance covering the outer periphery of the pair of strength members 105 and the optical fiber 103 and the pair of strength members 105. A long optical element portion 109 is configured.

  The long optical element portion 109 is integrated with a jacket 117 made of resin in which a support wire 115 made of, for example, steel wire is coated on the left side of the jacket 107 in the optical element portion 109 via a neck portion 113. A long optical fiber drop cable 121 is configured with the support line portion 119.

  In the optical element portion 109, a notch portion 123 is formed on the surface of the jacket 107 above and below the optical fiber 103.

  The outer cover 107 is made of a high-strength resin having low friction and wear resistance, so that measures are taken so that the laying tube does not pierce the outer cover 107.

Further, as known from Patent Document 2, a structure in which the outer cover has a two-layer structure, the hardness shore D of the inner cover is 65 or more, and the thickness is 0.15 mm or more is already known.
JP 2002-90591 A JP 2007-127848 A Proceedings of IEICE Proceedings 2007 Society Conference B-10-7

  By the way, in the optical fiber cable 101 shown in FIG. 3 as in the above-described Patent Document 1 and Non-Patent Document 1, the inclusion 111 becomes an obstacle when the optical fiber 103 is taken out. In addition, there is a problem that it takes time and labor to cut and remove the inclusion 111 that has come out of the jacket 107 when the optical fiber 103 is taken out.

  Further, in the optical fiber cable 121 shown in FIG. 4 described above, since the high-strength outer jacket 107 is used, the ones and wedges of the resin outer casing gripping member are sufficiently attached to the high-strength outer casing 107. There is a problem that it cannot be bitten and the grip strength of the outer jacket 107 is lowered. In addition, since the outer jacket 107 is hard, the tearing force required for tearing the outer jacket 107 is increased, and workability such as the lead-out property of the optical fiber 103 and the separation between the support wire portion 119 and the optical element portion 109 is reduced. . If the strength of the outer cover material is selected in consideration of the attachment property of the outer cover gripping member and the lead workability, the anti-kumazemi effect is reduced.

  Furthermore, in Patent Document 2, as a protective material, in addition to polyamide thermoplastic resin, ABS resin, ACS resin, AES resin, ABS / PVC alloy, ASA resin, ethylene-vinyl chloride copolymer, fluorine resin, polyamide Examples include imide, polyarylate, olefin vinyl alcohol copolymer, phenol resin, polybutylene terephthalate, polycarbonate, polyether sulfone, polythioether sulfone, polyethylene terephthalate, polyimide, norbornene resin, polyphenylene ether, polyphenylene sulfide, and polyvinyl chloride. ing. On the other hand, the jacket material of the optical fiber drop cable is made of olefin-based thermoplastic resin (polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate) due to the requirement of weather resistance against ultraviolet rays, combustion resistance, non-halogenation, etc. Copolymers etc.) as a main component, carbon black, and magnesium hydroxide as a flame retardant are generally used. These protective materials including polyamide-based resin applied as a suitable example in Patent Document 2 are poorly compatible with the flame-retardant olefin-based resin used as a jacket material for optical fiber drop cables, and have different melting points. Therefore, it is difficult to heat-seal during extrusion. In addition, as in the case of Patent Document 2, the structure in which the notch is provided on the short-diameter surface of the protective material, the outer layer jacket material can be provided even if the notch is provided in the central portion of the outer cover material of the cable portion It is impossible to take out the fiber core wire by tearing the notch part at the same time, and after tearing the outer sheath, it is necessary to tear the protective material further and take out the optical fiber core wire There is a problem that workability is worse than that of a conventional optical fiber drop cable.

  In order to solve the above-mentioned problems, an object of the present invention is to protect an optical fiber from a spawning tube of a pupa and prevent a reduction in connection work.

In order to achieve the problem to be solved by the invention described above, an optical fiber cable according to the invention includes one or more optical fibers disposed in a central portion,
A pair of two optical fibers extending in the longitudinal direction of the optical fiber on both sides of the optical fiber on a straight line parallel to one of two directions orthogonal to the longitudinal direction of the optical fiber and passing through the center of the optical fiber. A tensile body of
A first jacket having a Shore D hardness of 53 or less integrally coated on the outer periphery of the optical fiber and a pair of strength members;
An optical fiber cable constituting a long optical element portion consisting of:
The Shore D hardness is 55 or more from the upper and lower surfaces of the first jacket including a straight line parallel to the other direction of the two directions and passing through the center of the optical fiber to the inside of the first jacket. A second outer cover is formed, and the first outer cover and the second outer cover are integrally formed with each other, and the thickness of the second outer cover is 0.3 mm or more from the surface. It is 6 mm or less.

  In the optical fiber cable according to the present invention, in the optical fiber cable, it is preferable that a long support line portion in which a support line is covered with a jacket is integrated with the optical element portion in parallel with each other.

  As can be understood from the means for solving the above-described problems, according to the present invention, the second sheath having a Shore D hardness of 55 or more and having a Shore D hardness of 55 or more. An outer sheath is formed, and the first outer sheath and the second outer sheath are bonded together to form an optical fiber from a semi-vibrated tubule such as a bear jemi by the second outer sheath. Can be protected. In addition, when the thickness of the second jacket is 0.3 mm or more and 0.6 mm or less from the surface, and the Shore D hardness of the first jacket is 53 or less, when the first jacket is gripped by the closure and the connector The crab and wedge can be easily pierced into the first jacket, ensuring a stable gripping force, and having excellent optical fiber take-out performance.

  Since the conventional inclusion is not used, the workability is not deteriorated by the inclusion at the time of taking out the optical fiber.

  Embodiments of the present invention will be described below with reference to the drawings.

  Referring to FIG. 1, an optical fiber drop cable 1 includes one or more optical fibers 3 including, for example, an optical fiber core disposed in the center, and a longitudinal direction of the optical fiber 3 (in FIG. A straight line that is parallel to the X-axis direction (left-right direction in FIG. 1) of two directions (X-axis and Y-axis directions) orthogonal to the direction orthogonal to the center of the optical fiber 3. A pair of strength members 5 made of, for example, an aramid fiber FRP and the like, which are arranged to extend in the same direction as the longitudinal direction of the optical fiber 3 on both sides of the optical fiber 3 on the X axis, and the optical fiber 3 and a pair of strength members And a long outer optical element portion 9 including a first outer cover 7 made of a non-halogen flame retardant sheath integrally covered with the outer periphery of the outer peripheral portion 5.

  Of the two directions, the first jacket 7 is formed from the upper and lower surfaces 7A of the first jacket 7 including the straight Y-axis parallel to the other Y-axis direction and passing through the center of the optical fiber 3. A second outer cover 11 having a Shore D hardness of 55 or more is formed inside 7, and the first outer cover 7 and the second outer cover 11 are bonded together and formed integrally.

  A long support line portion 19 made of an outer sheath 17 covering a support wire 15 made of, for example, a steel wire is integrated with the optical element portion 9 in parallel with each other via a neck portion 13. In this embodiment, the same material as that of the first outer cover 7 is used for the outer cover 17.

  With the above-described configuration, even when the bearfish pierces the first envelope 7 with the egg-laying tube, the straight Y-axis parallel to the other Y-axis direction of the two directions and passing through the center of the optical fiber 3 is provided. The second outer cover 11 having a hardness higher than the hardness of the first outer cover 7 is formed from the upper and lower surfaces 7A of the first outer cover 7 to the inside of the first outer cover 7. The optical fiber 3 can be protected from being disconnected from the egg-laying tube. Further, by using a non-halogen flame retardant sheath as the first jacket 7, when the outer layer jacket 7 is gripped by a closure or a connector, the seam, the wedge or the like can be easily stuck in the first jacket 7, A stable gripping force can be secured.

  The first jacket 7 is made of a low-hardness jacket material equivalent to that of the conventional optical fiber cable, and the first jacket 7 is engaged with the connector and the closure jacket gripping member. A gripping force equivalent to that of the fiber cable can be maintained.

  The second jacket 11 is coated with a high hardness jacket material having a Shore D hardness of 55 or more. By shielding the periphery of the optical fiber 3 with this high-hardness outer covering material, the optical fiber 3 is protected from the egg-laying tube of the bearfish. The second outer cover 11 and the first outer cover 7 are both made of a thermoplastic resin. The first outer cover 7 is a non-halogen flame retardant resin mainly composed of an ethylene-based copolymer having a Shore D hardness of 53 or less. The cover 11 was made of a flame retardant polyolefin resin having a Shore D hardness of 55 or more, for example, a Shore D hardness of 63. During the extrusion molding, the joint surfaces of the second outer cover 11 and the first outer cover 7 are fused and integrated by heat sealing.

  Thereby, the 1st jacket 7 and the 2nd jacket 11 can be collectively torn using a tool. The optical fiber drop cable 101 having the inclusions 111 shown in FIG. 3 does not need to be individually treated with the jackets 107 and the inclusions 111 that protect the optical fiber 3, and the core wire picking workability is excellent. Yes.

  Next, about the effectiveness with respect to the fallopian tube damage of the bear zest about the 2nd jacket 11. The verification results are described.

An optical fiber drop cable 1 shown in FIG. 1 was prototyped using four types of polyolefin resins having different Shore D hardnesses, and the optical fiber drop cable 1 was installed on a tree where a bear-zemi actually appeared in summer for two months. After removal, the number and depth of the laying tube stab wound were measured. The results are as shown in Table 1.

  As can be seen from Table 1, in the conventional cable in which the jacket 107 having a Shore D hardness of 50 was coated, 55/100 m stabs were confirmed, and the maximum depth of these scratches was 1.1 mm. It was. In contrast, all of the resins A, B, and C having a Shore D hardness of 55 or more had few puncture scratches, and the depth of the scratches was 0.2 mm or less. It was also confirmed that the higher the Shore D hardness, the less stabs.

Therefore, the second jacket 11 in the optical fiber drop cable 1 shown in FIG. 1 has a Shore D hardness of 55 or more and is coated with a thickness of 0.3 mm or more from the surface of the second jacket 11, thereby providing the optical fiber 3. Can be protected. Desirably, if the Shore D hardness is 63 or more, stabs are further reduced and reliability is obtained. Note that the width of the second jacket 11 is orthogonal to the longitudinal direction of the optical fiber cable 1 because it is necessary to be able to shield the optical fiber 3 even when the laying tube is stabbed from an oblique direction. The length of each intersection of the optical fiber 3 where the straight X-axis passing through the center of the optical fiber 3 and the X-axis of the straight line intersect with the outer peripheries of a pair of strength members 5 arranged on both sides of the optical fiber 3 It is desirable to make the width B of the second jacket 11 longer than B (B ≧ A). Note that when the thickness of the second jacket 11 exceeds 0.6 mm from the surface, the take-out property of the optical fiber 3 deteriorates. In addition, if the first outer cover 7 is too hard, there is a problem that the resin outer cover holding member does not bite into the first outer cover 7. Table 2 shows the Shore D hardness of the first jacket 7 and the attachment of the connector jacket gripping member. Table 3 shows the influence of the thickness of the second jacket 11 and the Shore D hardness of the first jacket 7 on the take-out property of the optical fiber core wire.

  As can be seen from this result, if the Shore D hardness of the second jacket 11 is 55 or more, the thickness is 0.3 mm or more, and the Shore D hardness of the first jacket 7 is 53 or less, the second jacket 11 The optical fiber 3 is protected from the spawning tube of the bearfish, and when the first jacket 7 is gripped by the closure and the connector, the first and seventh wedges can be easily stuck in the first jacket 7 and the stable jacket gripping member It is possible to obtain the optical fiber cable 1 that secures the gripping force and has a good takeout property of the optical fiber 3. Desirably, if the Shore D hardness of the second jacket 11 is 63 or more, the thickness is 0.3 mm or more and 0.6 mm or less, and the Shore D hardness of the first jacket 7 is 48 or less, then the oak egg laying is further performed. The number of punctures caused by the tube can be further reduced to obtain the optical fiber cable 1 having higher reliability, ensuring the gripping force of the outer gripping member, and having good takeout performance of the optical fiber 3.

  Further, in order to secure the mechanical strength of the first jacket 7 of the optical fiber cable 1 and tear the second jacket 11 and the first jacket 7 together to take out the optical fiber 3, the first jacket 7 and the second outer cover 11 need to be easily attached and integrated at the time of extrusion. The material of the first jacket 7 used for the optical fiber cable 1 is an olefin-based thermoplastic non-halogen flame retardant resin (polyethylene, ethylene vinyl acetate co-polymer) due to requirements such as weather resistance against ultraviolet rays, combustion resistance, and environmental resistance. A combination of a blend, ethylene-acrylate copolymer, etc. as a main component, carbon black as a countermeasure against ultraviolet deterioration, and a non-halogen flame retardant such as magnesium hydroxide as a flame retardant is preferred. The material of the second outer cover 11 is such that it easily sticks to the first outer cover 7 by heat during extrusion, such as high-density polyethylene, olefin-based thermoplastic resin, high-density polyethylene, high-molecular-weight polyethylene, cyclic It is preferable to blend with polyolefin, polypropylene, etc. to increase the hardness, blend carbon black as a measure against ultraviolet deterioration, and blend with a non-halogen flame retardant as combustion resistance.

  From the above, the second jacket 11 is formed in the first jacket 7 having a Shore D hardness of 53 or less and having a Shore D hardness of 55 or more higher than the hardness of the first jacket 7. In addition, since the first outer cover 7 and the second outer cover 11 are integrally formed with each other, the second outer cover 11 protects the optical fiber 3 from the cicada oviposition tube such as a bearfish. can do. In addition, by using a non-halogen flame retardant sheath such as a non-halogen flame retardant sheath having a Shore D hardness of 53 or less, when the first jacket 7 is gripped by a closure or a connector, the first joint and the wedge are easy to grip. It is possible to secure a stable gripping force by sticking into the first outer cover 7.

    Since the conventional inclusion is not used, the workability is not deteriorated by the inclusion at the time of taking out the optical fiber.

  FIG. 1 described above describes the optical fiber cable 1, but the present invention is also applicable to FIG. 2 in which a jacket tearing groove (notch) 21 is provided in the center of the long diameter surface of the optical element portion 9 in FIG. 1. Is possible. As can be seen from Table 1, since the depth of the burrowing of the oak tube in the second jacket 11 with a Shore D hardness of 55 or more was 0.2 mm, the second outer sheath also in the optical fiber cable shown in FIG. If the thickness including the minimum thickness of the notch lower portion 21 of the cover 11 is 0.3 mm or more, it is possible to protect the optical fiber core wire from the laying tube of the bearfish.

  1 and 2 described the optical fiber drop cable 1, but the present invention can also be applied to an indoor optical fiber cable having no support line portion 21 in FIGS.

It is sectional drawing which shows the optical fiber cable of this invention. It is sectional drawing which shows the other optical fiber cable of this invention. It is sectional drawing which shows the conventional optical fiber cable. It is sectional drawing which shows the other conventional optical fiber cable.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical fiber drop cable 3 Optical fiber 5 Strength member 7 1st jacket 9 Optical element part 11 2nd jacket 13 Neck part 15 Support line 17 Cover 19 Support line part 21 Groove for jacket tearing

Claims (2)

One or more optical fibers disposed in the center;
A pair of two optical fibers extending in the longitudinal direction of the optical fiber on both sides of the optical fiber on a straight line parallel to one of two directions orthogonal to the longitudinal direction of the optical fiber and passing through the center of the optical fiber. A tensile body of
A first jacket having a Shore D hardness of 53 or less integrally coated on the outer periphery of the optical fiber and a pair of strength members;
An optical fiber cable constituting a long optical element portion consisting of:
The Shore D hardness is 55 or more from the upper and lower surfaces of the first jacket including a straight line parallel to the other direction of the two directions and passing through the center of the optical fiber to the inside of the first jacket. A second outer cover is formed, and the first outer cover and the second outer cover are integrally formed with each other, and the thickness of the second outer cover is 0.3 mm or more from the surface. An optical fiber cable having a length of 6 mm or less.   2. The optical fiber cable according to claim 1, wherein a long support line portion in which a support line is covered with a jacket is integrated in parallel with the optical element portion.

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