JP2011118386A - Flat type drop cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flat type drop cable which is configured such that tension restoration force generated by the hanging down of a first tension member does not affect a joining force between a sheath part and the first tension member. <P>SOLUTION: The flat type drop cable 100 is characterized in that it includes: an optical fiber unit 10; a pair of first tension members 20 arranged in parallel along the longitudinal direction of the optical fiber unit 10 in the upper/lower part of the optical fiber unit 10; a first sheath part 30 covering the optical fiber unit 10 and the first tension member 20; a second tension member 40 arranged in the upper part of the first sheath part 30; and a second sheath part 50 covering the second tension member 40. The drop cable satisfies a relation of F>k×ΔL(x) (wherein F is a joining force between the first tension member 20 and the first sheath part 30, k is an elastic modulus of the first tension member 20, and ΔL(x) is a length of the first tension member 20 extended under its own weight when an inter-post distance is 100 m). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a flat type drop cable including a pair of first strength members and one second strength member, and more specifically, a first strength member and a sheath for preventing deformation of an optical fiber. It is related with the flat type drop cable which improved the joining force with a part.

  In general, an optical cable includes an optical fiber unit that transmits an optical signal and a covering for protecting the optical fiber unit.

  Here, the covering for protecting the optical fiber unit has a structure in which a tensile body such as a steel wire or glass fiber reinforced plastic is inserted so as to withstand the tensile force applied in the process of laying the optical cable. Yes.

  In addition, in the case of an FTTH drop cable for connecting an optical cable to a house via a telephone pole, an optical fiber unit and a pair of strength members are surrounded by a sheath material, and a support wire is surrounded by a sheath material. It has a flat structure in which the support line portion is separated.

  Here, in order to implement the FTTH network, when cables are connected to the home via telegraph poles, cables are installed between the telegraph poles, and a tensile force is generated on the cables due to gravity. Stress is applied, and there is a risk of breakage.

  Therefore, in a general flat type drop cable, the first strength member 20 and the support wire 40 of the support wire portion serve as a protective material for preventing stress applied to the optical fiber unit 10 from the generated tensile force. become.

  However, when the flat drop cable is installed, as shown in FIG. 1, when a tensile force is generated in the cable 100 while the cable 100 hangs down due to the load of the cable 100 itself, the first located at the lower part of the optical fiber unit 10. The tensile body 20 of this type extends relative to the support line 40 on the upper side.

  Here, a tensile restoring force is generated in the first tensile body 20 on the lower side, which is relatively elongated, and this affects the bonding force between the sheath 30 and the first tensile body 20.

  Subsequently, when the tensile restoring force of the stretched first strength member 20 becomes larger than the bonding force between the sheath 30 and the first strength member 20, the two materials are released, and the first strength member 20 is removed. Becomes shorter than the sheath 30.

  As a result, the separated first strength member 20 cannot sufficiently function as a strength member, and the optical fiber unit 10 becomes stressed over time, and the optical signal due to the breakage of the optical fiber unit 10 occurs. Resulting in increased loss.

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to provide a tensile restoring force generated by the first strength member drooping when the flat drop cable is installed. It is an object of the present invention to provide a flat type drop cable configured so as not to affect the bonding force between the tensile strength member and the tensile strength member.

  Another object of the present invention is to provide a flat drop cable that can increase the bonding force between the sheath portion and the first strength member by coating the outer surface of the first strength member with an adhesive reinforcing member. There is.

  Still another object of the present invention is to provide a flat-type drop cable that can realize easy exposure of optical fibers during connection and connection of cables by forming a notch portion in a sheath portion.

According to the present invention, the object is to provide an optical fiber unit, a pair of first tensile bodies disposed in parallel along the length direction of the optical fiber unit at the upper and lower portions of the optical fiber unit, and the optical fiber unit. And a first sheath portion that covers the first strength member, a second strength member that is disposed on top of the first sheath portion, and a second sheath portion that covers the second strength member. , F> k · ΔL (x) is satisfied by the flat type drop cable. (F: bonding force between the first tensile body and the first sheath part, k: elastic coefficient of the first tensile body, ΔL (x): when the distance between the power poles is 100 m, due to the weight of the cable Length of stretched first strength member)
Here, the bonding force F between the first strength member and the first sheath portion is provided to be smaller than the breaking strength of the first strength member.

  The outer surface of the first strength member is coated with an adhesion reinforcing member for increasing the bonding force with the first sheath portion.

  Here, the adhesion reinforcing member is made of ethylene acetic acid or ethylene acrylic acid.

  The optical fiber unit is manufactured with a single-core optical fiber, a multi-core optical fiber, or a ribbon-type optical fiber.

  On the other hand, the first strength member is made of glass fiber reinforced plastic.

  The first sheath part may additionally include notch parts formed on both side parts along the length direction of the first sheath part.

  Here, the second strength member is made of a steel wire or a steel stranded wire.

  Further, the first sheath portion and the second sheath portion are provided integrally.

  Here, the first sheath portion and the second sheath portion are made of polyethylene (PE) or low smoke zero halogen (LSZH).

  According to the present invention, since the tensile restoring force generated when the first strength member hangs does not affect the bonding force between the sheath portion and the first strength member, the first strength due to the cable's own weight. The body is prevented from falling off.

  In addition, by coating the outer surface of the first strength member with the adhesion reinforcing member, the bonding force between the sheath portion and the first strength member is increased.

  Further, by forming the notch portion in the sheath portion, easy exposure of the optical fiber is realized at the time of connecting and connecting the cables.

It is a model figure of the flat type | mold drop cable installed between each telephone pole and drooping. It is a modeling graph of the flat type drop cable concerning the present invention. It is a perspective view of the flat type drop cable concerning the present invention. It is a perspective view of the flat type drop cable concerning other examples of the present invention.

  Hereinafter, a configuration of the present invention will be described in detail with reference to the accompanying drawings.

  Terms used in the specification and claims should not be construed to be limited to a dictionary meaning, but the inventor should apply the terminology concept in order to best explain the invention. It must be interpreted based on the principle that it can be defined in terms of meaning and concept consistent with the technical idea of the present invention.

  Accordingly, the embodiments described in the present specification and the configurations shown in the drawings are only preferred embodiments of the present invention and do not represent all the technical ideas of the present invention. It should be understood that various equivalents and variations can be substituted for these.

  FIG. 1 is a model diagram of a flat type drop cable installed between telephone poles, FIG. 2 is a modeling graph of a flat type drop cable according to the present invention, and FIG. 3 is a flat type according to the present invention. FIG. 4 is a perspective view of a drop cable, and FIG. 4 is a perspective view of a flat drop cable according to another embodiment of the present invention.

  1 to 4, a flat type drop cable 100 according to the present invention is disposed in parallel along the length direction of the optical fiber 10 and the upper and lower portions of the optical fiber 10. A pair of first strength members 20, a first sheath portion 30 covering the optical fiber 10 and the first strength member 20, and a second strength member 40 disposed on the top of the first sheath portion 30. And a second sheath portion 50 that covers the second strength member 40, and satisfies a relationship of F> k · ΔL (x) (F: between the first strength member and the first sheath portion) Bonding force, k: elastic coefficient of the first strength member, ΔL (x): length of the first strength member extended by the weight of the cable when the distance between the power poles is 100 m).

  Here, the optical fiber unit 10 is constituted by a unit assembly including one or more optical fiber core wires.

  Here, the optical fiber core wire is a portion through which an optical signal including data is transmitted. Generally, a glass optical fiber made of silica material having a high refractive index is used for a core portion, and a cladding portion is used. Is made of glass or synthetic resin having a low refractive index, and is designed to transmit the optical signal passing through the central portion by total reflection.

  Preferably, the optical fiber core wire is formed by coating a polymer resin on an outer surface of the core wire in order to mechanically protect the core portion and the clad portion.

  The optical fiber unit 10 is configured by a loose cable type in which the one or more optical fiber cores are arranged at a predetermined interval, or formed by closely attaching one or more optical fiber cores in the form of a ribbon. It is composed of a ribbon cable type.

  That is, the optical fiber unit 10 is manufactured with a single-core optical fiber, a multi-core optical fiber, or a ribbon-type optical fiber.

  The first strength member 20 is disposed at the upper and lower portions of the optical fiber unit 10, and is an element for protecting the optical fiber unit 10 by generating a tensile strength when the optical cable 100 is deformed such as bending. And it also performs the function of forming the central skeleton of the cable.

  Here, the first tensile body 20 is made of Kevlar aramid yarn, an epoxy fiber rod (Fiber glass epoxy rod), a glass fiber reinforced plastic, which is a material that is rigid but has a certain degree of elasticity. However, it is not limited to these.

  As shown in FIGS. 3 to 4, the optical fiber unit 10 and the first strength member 20 are surrounded by a first sheath portion 30.

  Here, the first sheath part 30 is a part that forms the outer shape of the cable and performs a mechanical protection function, and is made of polyethylene, low smoke zero halogen (LSZH), PVC or Although it is made of an insulating material such as an olefin polymer, it can be variously modified within the scope of a known technical idea depending on the purpose of use and the installation environment.

  Further, a glass fiber layer is disposed inside the first sheath portion 30 in order to improve the cable strength and the cable bending characteristics.

  In addition, a metal jacket may be additionally formed inside the first sheath portion 30 in order to block external interference due to electromagnetic waves generated from other adjacent cables or other electronic equipment. it can.

  Further, the first sheath part 30 may additionally include notch parts 32 formed on both sides along the length direction of the first sheath part 30.

  Here, when the optical cable 100 is connected or connected, the notch portion 32 peels off the first sheath portion 30 and exposes the optical fiber unit 10 to facilitate peeling of the first sheath portion 30. It is a component.

  On the other hand, the second strength member 40 is disposed on the upper portion of the first sheath portion 30 that covers the optical fiber unit 10 and the pair of first strength members 20, and reinforces the strength of the cable 100. Is an element.

  Preferably, the second strength member 40 is made of a steel wire or a steel stranded wire, and is made of a Kevlar aramid yarn, an epoxy fiber rod, or a glass fiber reinforced plastic. However, it is not limited to these.

  As shown in FIGS. 3 to 4, the second strength member 40 is covered with a second sheath portion 50, and the first sheath portion 30 and the second sheath portion 50 are provided integrally. It is done.

  Here, the second sheath portion 50 is formed integrally with the first sheath portion 30, and is formed continuously or intermittently along the length direction of the optical cable 100.

  In addition, the second sheath portion 50 is made of polyethylene (PE), low smokeless halogen (LSZH), PVC, or an olefin polymer material, like the first sheath portion 30 described above. Consists of insulating materials such as.

  The flat drop cable manufactured using the above-described components has a tensile restoring force generated by the first tensile body 20 hanging when the cable is installed, and the first sheath portion 30 and the first tensile body 20 Provide a structure that does not affect the bonding force between the two.

  In more detail, the cable installed between the two telephone poles has a catenary line as shown in the graph of FIG. 2 (when both ends of a uniform rope are fixed at two positions at the same height, It is modeled by an equation) and expressed mathematically as the following equation.

（Ｈ：ケーブルの水平張力、ｗ：単位長さ当たりのケーブルの重さ）
また、前記懸垂線方程式でモデリングされた第２の抗張力体４０を被覆する第２のシース部５０と第１の抗張力体２０の方程式から、任意の点で第２のシース部５０と第１の抗張力体２０の伸びた長さの差ΔＬ（ｘ）は、下記の式のように整理される。

(H: Horizontal tension of cable, w: Weight of cable per unit length)
Further, from the equations of the second sheath portion 50 and the first strength member 20 that cover the second strength member 40 modeled by the catenary line equation, the second sheath portion 50 and the first strength point at any point can be obtained. The stretched length difference ΔL (x) of the strength member 20 is arranged as shown in the following equation.

ここで、ｐは、第２のシース部５０と第１の抗張力体２０との間の距離を意味し、Ｈは、ケーブルの水平張力を意味し、ｗは、ケーブルの単位長さ当たりの重さを意味するもので、前記式を用いて第１の抗張力体２０の伸びた長さによる引張復元力は、下記の式のように整理される。

Here, p means the distance between the second sheath portion 50 and the first strength member 20, H means the horizontal tension of the cable, and w means the weight per unit length of the cable. This means that the tensile restoring force due to the extended length of the first strength member 20 using the above formula is arranged as the following formula.

ここで、ｋは、第１の抗張力体自体の弾性係数を意味する。

Here, k means the elastic coefficient of the first strength member itself.

  By using the above mathematical formula, the first strength member is formed by forming the bonding force between the first strength member 20 and the first sheath portion 30 to be equal to or greater than the tensile restoring force of the first strength member 20. The detachment of the first sheath portion 30 and the first strength member 20 caused by the tensile restoring force of 20 can be prevented, and thereby stress applied to the optical fiber unit 10 can be prevented.

  That is, by manufacturing the cable in consideration of the influence of the tensile restoring force of the first strength member 20 generated when the cable is installed, the joining force between the first strength member 20 and the first sheath portion 30 is the first. It is possible to design a cable that is equal to or larger than the tensile restoring force of the tensile strength member 20 of the above.

  Here, in order to increase the bonding force between the first strength member 20 and the first sheath portion 30, after the adhesion reinforcing member 22 is coated on the outer surface of the first strength member 20, the first strength member 20 is coated with the first strength member 20. The tensile body 20 and the first sheath portion 30 are coupled.

  Preferably, the adhesive reinforcing member 22 is made of ethylene acetic acid or ethylene acrylic acid, and is coated on the outer surface of the first strength member 20, but is not limited thereto. It can also be coated with any kind of adhesive.

  On the other hand, the bonding force F between the first strength member 20 and the first sheath portion 30 is set to be equal to or smaller than the breaking strength of the first strength member 20 itself.

  That is, the bonding strength between the first strength member 20 and the first sheath portion 30 is equal to or greater than the tensile restoring force due to the extended length of the first strength member 20, and the first strength By constituting the same or smaller than the breaking strength of the body 20 itself, it is possible to prevent the first strength member 20 and the first sheath portion 30 from being detached due to the weight of the cable.

  Therefore, according to the flat type drop cable 100 according to the present invention, the first tensile body 20 and the first sheath portion 30 are prevented from falling off, and the optical fiber unit 10 can be protected from stress due to the weight of the cable. It is possible to reduce the loss rate of the optical signal.

  As described above, in the flat type drop cable according to the present invention, the tensile restoring force generated when the first strength member hangs does not affect the bonding force between the sheath portion and the first strength body. The first strength member is prevented from falling off due to the weight of the cable. Further, by coating the outer surface of the first strength member with an adhesion reinforcing member, the bonding force between the sheath portion and the first strength member is increased, and by forming a notch portion in the sheath portion, the cable connection and Easy exposure of the optical fiber is realized at the time of connection.

  As described above, the present invention has been described with reference to the limited embodiments and drawings. However, the technical idea of the present invention is not limited thereto, and a person having ordinary knowledge in the technical field to which the present invention belongs. Various modifications and variations may be made within the scope of the technical idea of the present invention and the scope of the following claims.

DESCRIPTION OF SYMBOLS 10 Optical fiber unit 20 1st strength body 22 Adhesive reinforcement member 30 1st sheath part 32 Notch part 40 2nd strength body 50 2nd sheath part 100 Flat type drop cable

Claims (10)

An optical fiber unit;
A pair of first strength members disposed in parallel along the length direction of the optical fiber unit at the upper and lower portions of the optical fiber unit;
A first sheath covering the optical fiber unit and the first tensile body;
A second strength member disposed on top of the first sheath portion;
A second sheath covering the second strength member,
F> k · ΔL (x)
(F: bonding force between the first tensile body and the first sheath part, k: elastic coefficient of the first tensile body, ΔL (x): when the distance between the power poles is 100 m, due to the weight of the cable Length of stretched first strength member)
Flat type drop cable characterized by satisfying the above relationship.   2. The flat drop cable according to claim 1, wherein a bonding force F between the first strength member and the first sheath portion is smaller than a breaking strength of the first strength member.   The flat drop cable according to claim 1, wherein an outer surface of the first strength member is coated with an adhesion reinforcing member for increasing a bonding force with the first sheath portion.   The flat type drop cable according to claim 3, wherein the adhesion reinforcing member is made of ethylene acetic acid or ethylene acrylic acid.   The flat type drop cable according to claim 1, wherein the optical fiber unit is made of a single-core optical fiber, a multi-core optical fiber, or a ribbon-type optical fiber.   The flat drop cable according to claim 1, wherein the first strength member is made of glass fiber reinforced plastic.   2. The flat drop cable according to claim 1, wherein the first sheath portion additionally includes notches formed on both sides along the length direction of the first sheath portion. .   The flat drop cable according to claim 1, wherein the second strength member is made of a steel wire or a steel stranded wire.   The flat drop cable according to claim 1, wherein the first sheath portion and the second sheath portion are provided integrally. The flat drop according to claim 9, wherein the first sheath part and the second sheath part are made of polyethylene (PE) or low smoke zero halogen (LSZH). cable.

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