JP2012032572A - Optical fiber cable - Google Patents

Abstract

The present invention provides an optical fiber cable having a structure that is not damaged by puncture of an optical fiber core wire by an oviposition tube such as a bear swallow without providing a protective wall member inside the cable.
An optical fiber cable includes an optical fiber core wire 6, tension members 10 disposed on both sides of the optical fiber core wire 6, and a cable jacket 9 that collectively covers these members. The cable jacket 9 has a tensile fracture strength measured in accordance with JIS K7113 of 15 MPa or more, a durometer hardness measured in accordance with JIS K7215 of HDD50 or more, and in any cross section perpendicular to the cable axial direction, The length of the line segment connecting the optical fiber core wire or the optical fiber tape core wire and the surface of the jacket is 0.4 mm or more.
[Selection] Figure 4

Description

  The present invention relates to an optical fiber cable for drawing an optical fiber into a subscriber's house. More specifically, the present invention relates to an improvement in a drop optical fiber cable that can prevent an optical fiber from being damaged by a stab by making it possible to prevent the entry of an oviposition tube during spawning of a cocoon such as a courge.

The drop optical fiber cable is configured such that the optical fiber core wire, the tension member, and the support wire are arranged so as to be included in the same plane and are collectively covered with a jacket. When a drop optical fiber cable is used in an aerial environment, there are many cases in which the outer sheath of the cable is damaged due to the stab wound by the spawning of the bearfish and the internal optical fiber core is broken (see Non-Patent Document 1).
The cause of the failure is that the bearfish punctures the egg-laying tube into the drop optical cable for laying eggs and damages the inner optical fiber. In detail, when the drop optical fiber cable is invaded by the laying tube, the stress is concentrated on the intruded portion, and the optical fiber is broken and broken. Therefore, as these countermeasures, a drop optical fiber cable in which a protective wall member is provided inside the cable has been devised and used in order to keep the invasion of the laying tube at a certain depth (see Patent Document 1).

JP 2006-195109 A

Kimio Ando et al., B-10-17 “Study on Drop Optical Fiber Cable Technology for Countermeasures against Semi-damage”, 2001 IEICE General Conference Proceedings Communication 2, March 7, 2001, pp. 450

However, the conventional countermeasure article is effective for stab damage caused by the spawning tube of the bearfish, but the provision of the protective wall member has caused an increase in the cable material cost.
In addition, the conventional countermeasure article has a problem that the construction cost increases because the number of steps for removing the protective wall during construction increases, and further, the construction becomes complicated.

  The present invention has been made in view of such problems, and the object of the present invention is to prevent the optical fiber core from being stabbed by an oviposition tube such as a bear swallow without providing a protective wall member inside the cable. It is to provide an optical fiber cable having no structure.

In order to achieve the above object, in the present invention, even if the laying tube enters and the cable jacket is damaged, the inner optical fiber core is not affected by the stab, that is, allowed. “Hardness (durometer hardness)” and “Tensile strength (tensile fracture strength) that the cable jacket should have in order to prevent the penetration of the laying tube from reaching its allowable depth after clarifying the“ stab depth ” ) ”Was clarified by experiments and the cable structure was clarified.
As a result, the present invention has the ability to prevent damage to the optical fiber core wire due to the puncture of the spawning tube of the black oak without providing a protective wall member, and can be manufactured at a low cost, thereby improving the workability during construction. Can be improved.

  That is, the present invention relates to an optical fiber cable comprising one or more optical fiber cores or optical fiber tape cores, tension members arranged at intervals on both sides thereof, and a jacket covering them all at once. The outer sheath has a tensile fracture strength measured in accordance with JIS K7113 of 15 MPa or more, a durometer hardness measured in accordance with JIS K7215 of HDD50 or more, and the optical fiber core on a cross section perpendicular to the cable axis direction. The length of the line segment connecting the wire or the optical fiber ribbon and the surface of the jacket is 0.4 mm or more.

  Further, the present invention provides an optical fiber cable comprising one or more optical fiber cores or optical fiber tape cores, tension members disposed at intervals on both sides thereof, and a jacket covering them all at once. A first jacket that covers the optical fiber core or optical fiber ribbon and the tension member to form a cable center, and a second jacket that covers the first jacket The first outer cover has a tensile fracture strength measured in accordance with JIS K7113 of 15 MPa or more, a durometer hardness measured in accordance with JIS K7215 of HDD50 or more, and a cross section perpendicular to the cable axis direction. In the above, the length of a line segment connecting the optical fiber core wire or the optical fiber tape core wire and the surface of the second jacket is 0.4 mm or more. It is a sign.

  Further, the present invention provides an optical fiber cable comprising one or more optical fiber cores or optical fiber tape cores, tension members disposed at intervals on both sides thereof, and a jacket covering them all at once. The jacket includes a first jacket that covers the optical fiber core or the optical fiber ribbon, and a second jacket that covers each of the first jacket and the tension member. 1 has a tensile fracture strength measured in accordance with JIS K7113 of 15 MPa or more and a durometer hardness measured in accordance with JIS K7215 of HDD50 or more. The length of the line segment connecting the fiber core or the optical fiber ribbon and the surface of the first jacket is 0.4 mm or more.

  It is preferable that the outer cover has a slit groove on the outer cover surface. Moreover, it is preferable that the said jacket is provided with the support wire which supports a cable main body on the outer side of a jacket.

INDUSTRIAL APPLICABILITY The present invention can prevent a disconnection failure of an optical fiber core wire caused by an egg-laying tube such as a bearfish.
Moreover, since the member for protecting optical fiber core wires, such as a protective wall, is unnecessary for this invention, it can hold down cable material cost low.
Further, according to the present invention, the cable structure is simplified due to the omission of the protective wall and the like, and therefore, the work for taking out the core wire and the terminal processing work at the time of construction become easy, and the construction time can be shortened.
Furthermore, the present invention can be expected to reduce failure due to the improved workability during construction.

It is a figure which shows the execution method of a bear-zemi tolerance test. It is a figure which shows the measuring method of the puncture depth. It is the figure which graphed the relationship between tensile fracture strength, durometer hardness, and stab depth. It is a figure which shows the drop optical fiber cable which concerns on Example 1 of this invention. It is a figure which shows the drop optical fiber cable which concerns on Example 1 of this invention. It is a figure which shows the drop optical fiber cable which concerns on Example 1 of this invention. It is a figure which shows the drop optical fiber cable which concerns on Example 1 of this invention. It is a figure which shows the drop optical fiber cable which concerns on Example 2 of this invention. It is a figure which shows the drop optical fiber cable which concerns on Example 2 of this invention.

First, the conditions of the cable jacket having the resistance to the bear burrow are examined.
<Acceptable stab depth>
Since it is difficult to realize a jacket that completely prevents stabbing caused by spawning of the burdock, the permissible stab depth is specified. In order to make it easy to take out the optical fiber core, the drop optical fiber cable is provided with a tearing groove called a notch extending in the longitudinal direction in parallel with the optical fiber core. About 0.2 mm is necessary.

  The number of cores of the drop optical fiber cable is generally 1 core, 2 cores, 4 cores of 4 cores optical fiber tape, and 8 cores of 4 cores of optical fiber tape. The case where the distance between the line and the surface is the smallest is the case where two four-fiber optical fiber tapes are used.

  When the width in the short side direction of the drop optical fiber cable having a substantially rectangular cross-sectional shape is 1.8 to 2.2 mm, the distance from the center of the cable to the surface is 0.9 to 1.1 mm. Since the thickness of the optical fiber tape is generally about 0.3 mm, the thickness of the jacket is about 0.6 to 0.8 mm when these thicknesses are taken into consideration. Furthermore, when the width of the notch is subtracted, the distance from the cable surface to the tape is at least 0.4 mm. From this, it is considered that if the puncture is 0.4 mm or less, the disconnection of the optical fiber core wire can be prevented. Therefore, the allowable stab depth required for the Coomassemi-resistant outer jacket is set to 0.4 mm.

<Examination of jacket material parameters>
(Durometer hardness)
Generally, the quantity representing the magnitude of resistance to deformation when a local force is applied to a substance from outside for a short time is called hardness. Hardness was considered as one of the parameters because it was considered necessary to have high resistance to local force in order to resist the insertion of the oviposition of Komazemi. There are various types of hardness, but the durometer hardness (JIS K7215), which measures the resistance when a needle-shaped indenter is inserted, is considered to be close to the insertion state of the oviposition tube of the black oak, and the durometer hardness is examined. It was adopted as one of the parameters.

(Tensile fracture strength)
As described above, the resistance to the invasion of the laying tube is secured by the hardness, but on the other hand, the problem of the brittleness of the material itself needs to be considered. Even if the brittle material has the necessary hardness, it cannot withstand long-term stress, leading to the destruction of the outer jacket. In other words, the second condition was considered to be a tenacious material. Therefore, the strength of the material is determined based on the parameter of tensile fracture strength (JIS K7113) representing the strength of the material.

  In order to confirm the relationship between the tensile fracture strength and the durometer hardness with respect to the permissible stab depth selected by the above examination, trial production of 12 types of drop optical fiber cables with different tensile fracture strength and durometer hardness (hereinafter, (Referred to as a sample) was prepared, and an experiment for resistance to Coomasemi was performed.

<Confirmation of bearsemi resistance>
FIG. 1 is a diagram showing a method for carrying out a Komazemi tolerance test. The material parameter region that is effective against the kuma-zemi was confirmed by actually capturing the koma-zemi and causing the cable under test (drop optical fiber cable) 2 to try to lay eggs. The experiment was conducted (July to August) in accordance with the egg-laying season of the bearfish.

  By placing the bearfish on the cable 2 to be tested, a state in which the bearfish jumped on the cable in a pseudo manner was created, and egg-laying was attempted. At that time, the evaluator controlled the number of times of contact so that the number of times the bear juniper contacts each cable is not biased so that the bear jemi is equally in contact with each cable.

  FIG. 2 is a diagram showing a method for measuring the puncture depth. The cable which finished the egg-laying test of the kuma-zemi disassembled each stab 3 and measured the distance (stabbed depth 4) from the surface of the cable jacket 5 to the deepest part of the stab 3. For the data of the stab depth 4, the 99.7% confidence interval is considered to be the safety region, and the value obtained by adding the value of 3 times the sample standard deviation to the average value (average value + 3σ) and the stab depth of each sample. did.

Table 1 shows the verification results of the Komazemi tolerance test.

  In Samples 1 to 6, the average value of stab depth + 3σ exceeded 0.4 mm (allowable stab depth), and did not satisfy the specified value. Samples 7 to 15 satisfied the specified value. FIG. 3 is a graph showing the relationship between tensile fracture strength, durometer hardness, and puncture depth.

  Considering the results, the higher the tensile fracture strength and the greater the durometer hardness, the higher the resistance to egg-laying in the courges. It was confirmed that the coating material parameter region that can ensure the allowable stab depth is a tensile fracture strength of 15 MPa or more and a durometer hardness of HDD50 or more.

The optimal cable was examined from the result of the above trial production. Examples are given below.
<Example 1>
The drop optical fiber cable which concerns on Example 1 is shown in FIGS. 4 shows a drop optical fiber cable using one optical fiber core, FIG. 5 shows a drop optical fiber cable using two optical fiber cores, and FIG. FIG. 7 shows a drop optical fiber cable using one four-fiber optical fiber ribbon, and FIG. 7 shows a drop optical fiber cable using two four-fiber optical fiber ribbons.

  The drop optical fiber cable includes a cable portion and a support wire portion. The cable portion includes a cable jacket 9 having a substantially rectangular cross-sectional shape, and an optical fiber core wire 6 or an optical fiber provided at the center of the cable jacket 9. It comprises a fiber tape core 7 and tension members 10 arranged on both sides of the optical fiber core 6 or the optical fiber tape core 7 in order to prevent tension from being applied to the optical fiber core 6 or the optical fiber tape core 7. The support wire 11 is provided in the support wire portion. The cable jacket 9 is provided with a notch 8 extending in the longitudinal direction parallel to the optical fiber core wire 6 or the optical fiber tape core wire 7.

  The drop optical fiber cable according to Example 1 is obtained by applying a material having a tensile fracture strength measured according to JIS K7113 to 15 MPa or more and a durometer hardness measured according to JIS K7215 to HDD50 or more to the cable jacket 9. Furthermore, in an arbitrary cross section perpendicular to the cable axial direction, the length of the line segment connecting the optical fiber core wire 6 or optical fiber tape core wire 7 and the surface of the cable jacket 9 is 0.4 mm or more. It is characterized by being.

<Example 2>
A drop optical fiber cable according to the second embodiment is shown in FIGS. The drop optical fiber cable according to the second embodiment is obtained by applying a cable jacket 9 that is resistant to Coomasemi to a part of a normal cable jacket 12. The drop optical fiber cable shown in FIG. 8 is composed of a cable jacket 9 that is bearsemi-resistant and a normal cable jacket 12 that covers the cable jacket 9. 9 is a configuration including the optical fiber core wire 6 and the tension member 10, and the drop optical fiber cable shown in FIG. 9 has a cable jacket 9 that is resistant to bearsemi and an outer side of the cable jacket 9. The cable jacket 9 includes the optical fiber core wire 6, and the cable jacket 12 includes the tension member 10.

  The drop optical fiber cable according to Example 2 includes a part of a cable jacket 9 made of a material having a tensile fracture strength measured in accordance with JIS K7113 of 15 MPa or more and a durometer hardness measured in accordance with JIS K7215 of HDD50 or more. Further, the cable jacket 9 and the cable jacket 12 are not easily separated from each other, and in any cross section perpendicular to the cable axial direction, an optical fiber core or an optical fiber The length of the line segment connecting the tape and the surface of the cable jacket is 0.4 mm or more.

  In the second embodiment, by using a general drop optical fiber cable material as the jacket material, it is possible to take countermeasures against bear spot while maintaining good consistency with peripheral members that are in direct contact with the cable.

  Also in the second embodiment, any one of a single fiber, a single fiber, a four-fiber optical fiber tape, and a four-fiber optical fiber tape may be used as the optical fiber.

  In the above-described embodiment, the drop optical fiber cable has been described. However, the present invention is not limited to this, and can be applied to an indoor optical fiber cable without a support line.

  In the above-described embodiment, the optical fiber cable has a tearing groove called a notch 8 in the vicinity of the center of the cable portion in order to facilitate the operation of taking out the optical fiber core. It is applicable also to the optical fiber cable which does not have.

2 cable under test 3 stab wound 4 stab depth 5 cable jacket 6 optical fiber core wire 7 4 core optical fiber tape 8 notch 9 komazemi resistant cable jacket 10 tension member 11 support wire 12 normal cable jacket

Claims (5)

In an optical fiber cable comprising one or more optical fiber cores or optical fiber tape cores, tension members arranged at intervals on both sides thereof, and a jacket covering them all at once,
The outer sheath has a tensile fracture strength measured in accordance with JIS K7113 of 15 MPa or more, a durometer hardness measured in accordance with JIS K7215 of HDD50 or more, and the optical fiber on a cross section perpendicular to the cable axis direction. An optical fiber cable, wherein a length of a line segment connecting the core wire or the optical fiber tape core wire and the surface of the jacket is 0.4 mm or more. In an optical fiber cable comprising one or more optical fiber cores or optical fiber tape cores, tension members arranged at intervals on both sides thereof, and a jacket covering them all at once,
A first jacket that covers the optical fiber core or optical fiber ribbon and the tension member to form a cable center; and a second jacket that covers the first jacket. The first outer cover has a tensile fracture strength measured in accordance with JIS K7113 of 15 MPa or more, a durometer hardness measured in accordance with JIS K7215 of HDD50 or more, and is perpendicular to the cable axis direction. An optical fiber cable, wherein a length of a line segment connecting the optical fiber core wire or the optical fiber tape core wire and the surface of the second jacket is 0.4 mm or more on a cross section. In an optical fiber cable comprising one or more optical fiber cores or optical fiber tape cores, tension members arranged at intervals on both sides thereof, and a jacket covering them all at once,
The jacket is composed of a first jacket covering the optical fiber core or the optical fiber tape core, and a second jacket covering each of the first jacket and the tension member, The first outer cover has a tensile fracture strength measured in accordance with JIS K7113 of 15 MPa or more, and a durometer hardness measured in accordance with JIS K7215 of HDD50 or more, on a cross section perpendicular to the cable axial direction, An optical fiber cable, wherein a length of a line segment connecting the optical fiber core wire or the optical fiber tape core wire and the surface of the first jacket is 0.4 mm or more.   The optical fiber cable according to any one of claims 1 to 3, wherein the outer cover is provided with a tearing groove on a surface of the outer cover.   The optical fiber cable according to any one of claims 1 to 4, wherein the outer jacket includes a support wire that supports the cable body on an outer side of the outer jacket.

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