JP2012003062A - Optical fiber cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical fiber cable that does not cause micro-bending on an optical fiber core wire even when the cable is clamped by a P-clamp.SOLUTION: An optical fiber cable 1 has a cable support part 13 through a connection part 9 on one side of a cable body 7 having an optical fiber core wire 5 arranged between a pair of tension members 3. When a longitudinal direction of the optical fiber cable 1 is defined as a Z-axis direction, an arrangement direction of the tension members 3, the optical fiber core wire 5 and the cable support part 13 is defined as a Y-axis direction, and a direction orthogonal to the Z-axis direction and the Y-axis direction is defined as an X-axis direction, grooves 25A and 25B having wider widths than a diameter of the optical fiber core wire 5 are provided long in the Z-axis direction at positions corresponding to the optical fiber core wire 5 on both sides of the cable body 7 in the X-axis direction. Distances from a shaft center of the optical fiber core wire 5 to bottom parts 29A and 29B of the grooves 25A and 25B are longer than a radius of the optical fiber core wire 5 and shorter than a radius of a supporting line 11 provided on the cable support part 13.

Description

  The present invention relates to an optical fiber cable for drawing an optical line into a subscriber's house, and more particularly to an optical fiber cable that can be used not only in Japan but also overseas.

  Conventionally, in order to be able to send and receive high-speed broadband information such as ultra-high-speed data at FTTH (Fiber to the Home), that is, at home or in the office, an optical fiber cable extended from a telephone station is sent to a subscriber's house such as a general house. A suitable optical fiber drop cable is used for wiring the optical fiber cable core wire (see, for example, Patent Documents 1 and 2).

JP 2010-39057 A JP 2000-171673 A

  As shown in FIG. 1A, the optical fiber cable 1 described in Patent Documents 1 and 2 includes a Y-axis of a cable body 7 provided with an optical fiber core wire 5 disposed between a pair of strength members 3. A cable support portion 13 having a large-diameter support wire 11 is integrally provided on one side of the direction via a connecting portion (neck portion) 9. More specifically, the pair of strength members 3, the optical fiber core wire 5, and the support wire 11 are arranged in a line in the Y-axis direction (vertical direction in FIG. 1A), and are made of an appropriate thermoplastic resin. It is covered integrally. And the notch part 15 is formed in the both sides | surfaces of the X-axis direction (left-right direction in FIG. 1 (A)) of the said cable main body 7. As shown in FIG.

  When the optical fiber cable 1 having the above configuration is pulled down to each home, a part of the connecting portion 9 at both ends of the optical fiber cable 1 is cut off to separate the cable body 7 and the cable support portion 13. Then, one end of the cable support 13 is connected and fixed to an outdoor wire clamp (not shown) of a utility pole (not shown), and the other end of the cable support 13 is provided in a part of the house ( (Not shown). One end of the optical fiber core wire 5 is connected to a cable branch box (not shown) provided on the utility pole, and the other end is connected to an indoor OE converter (not shown).

  By the way, in the optical fiber cable 1A used overseas, as shown in FIG. 1B, large-diameter strength members 3A are arranged on both sides of the optical fiber core wire 5A, and the pair of strength members 3A and The optical fiber core wire 5A is covered with a thermoplastic resin. And the thing for which the said optical fiber cable 1A is fastened to poles, such as an electric pole, for example, what is called a P-clamp in WO2009 / 070200 is used. The P-clamp 17 is configured as shown conceptually and schematically in FIG.

  That is, the P-clamp 17 as an outdoor wire clamp includes a clamp body 19, a gripper 21, and a wedge member 23. The clamp body 19 is formed by bending a metal plate to include side wall surface portions 19B on both sides of the ceiling surface portion 19A and having a substantially C-shaped cross section. The ceiling surface portion 19A of the clamp body 19 is provided with an uneven portion 19C over an appropriate range. The side wall surface portion 19B is formed in a wedge shape by making the height dimension on the other end side smaller than the height dimension on the one end side. A bent portion 19D that is bent inward is provided at the lower edge of the side wall surface portion 19B.

  The gripper 21 is formed in a plate shape with plastic or the like, and the width of the central portion 21A is a width that can enter between both side wall surface portions 19B of the clamp body 19, and both ends of the central portion 21A have An extension portion 21 </ b> B that is held in a state of protruding outward from both ends of the clamp body 19 is provided. The central portion 21A of the gripper 21 is provided with a plurality of convex portions 21C at appropriate intervals.

  The wedge member 23 includes a pressing surface 23A that presses the gripper 21 disposed in the clamp body 19 toward the ceiling surface portion 19A. On both sides of the pressing surface 23A, there are provided wedge-like side wall portions 23B that engage with guide grooves 19E between the side wall surface portions 19B and the bent portions 19D of the clamp body 19. The pressing surface 23A of the wedge member 23 is provided with a plurality of hemispherical convex portions 23C, and a suspension tool 23D is provided on one end side where the height of the side wall portion 23B is small.

  When the optical fiber cable 1 is clamped by the P-clamp 17 having the above configuration, the configuration is conceptually and schematically shown in FIG. That is, after the optical fiber cable 1 is inserted and disposed in the clamp body 19, the gripper 21 is disposed in the clamp body 19 and the wedge member 23 is engaged in the clamp body 19 (state shown in FIG. 3). Then, by pulling the hanger 23D, the gripper 21 is pressed to the ceiling surface portion 19A side of the clamp body 19 by the wedge action of the wedge member 23 and the like, and the optical fiber cable is interposed between the ceiling surface portion 19A and the gripper 21. 1 is firmly clamped.

  At this time, as schematically shown in FIG. 3, the entire cable support portion 13 and the cable body 7 of the optical fiber cable 1 are firmly held between the ceiling surface portion 19 </ b> A of the clamp body 19 and the gripper 21. Become. As shown in FIG. 2, the ceiling surface portion 19A of the clamp body 19 is formed with an uneven portion 19C over an appropriate range, and the central portion 21 of the gripper 21 has a plurality of convex portions 21C. By being formed at appropriate intervals, the portion of the coated thermoplastic resin is pressurized and greatly deformed. Therefore, a lateral pressure load in the vertical direction in FIG. 3 is applied to the optical fiber core wire 5 in the optical fiber cable 1, and the notch portion 15 having a shallow depth is deformed, and a lateral pressure is also applied to the bottom of the notch portion 15. Become. Therefore, there is a problem in that a slight bend (microbend) occurs in the optical fiber core wire 5 and transmission loss increases.

  That is, there is a problem in clamping the conventional optical fiber cable 1 used in Japan with the P-clamp 17. Therefore, there is a demand for an optical fiber cable that can be applied to both the outdoor wire clamp used in the country and the P-clamp 17 described above.

  The present invention has been made in view of the above-described problems, and includes a cable support portion on one side of a cable body provided with an optical fiber core wire disposed between a pair of strength members via a connecting portion. The longitudinal direction of the optical fiber cable is the Z-axis direction, the arrangement direction of the tensile body, the optical fiber core wire and the cable support is the Y-axis direction, and the Z-axis direction and the direction perpendicular to the Y-axis direction are the X-axis direction. The optical fiber is provided with a groove longer than the diameter of the optical fiber core in the Z-axis direction at positions corresponding to the optical fiber core on both side surfaces in the X-axis direction of the cable body. The distance from the axis of the core wire to the bottom of the groove is larger than the radius of the optical fiber core wire and smaller than the radius of the support wire provided in the cable support portion. .

  In the optical fiber cable, the bottom of the groove is formed in a V shape.

  According to the present invention, even when the optical fiber cable is firmly held by the P-clamp, the deformation of the cable body portion is absorbed in the groove portion. Therefore, a large lateral pressure does not act on the optical fiber core wire and no microbend is generated, and the conventional problems as described above can be solved.

It is explanatory drawing which shows the structure of the conventional common optical fiber cable. FIG. 3 is an exploded perspective view schematically showing a configuration of a P-clamp. It is explanatory drawing of the state before clamping an optical fiber cable to a P-clamp and clamping firmly. It is explanatory drawing which shows the structure of the optical fiber cable which concerns on embodiment of this invention.

  Hereinafter, the configuration of the optical fiber cable according to the embodiment of the present invention will be described in detail with reference to the drawings. The same reference numerals are given to components having the same functions as those of the conventional optical fiber cable 1 described above. The explanations made are omitted.

  Referring to FIG. 4, the overall configuration of the optical fiber cable 1 according to the embodiment of the present invention is similar to the conventional optical fiber cable shown in FIG. In order to facilitate understanding of the configuration of the optical fiber cable 1, the longitudinal direction of the optical fiber cable 1 (the direction perpendicular to the paper surface in FIG. 4A) is the Z-axis direction, and the strength member 3, the optical fiber core wire 5. The support wire 11, that is, the arrangement direction of the cable support portion 13 (vertical direction in FIG. 4A) is the Y-axis direction. A direction orthogonal to the Z-axis direction and the Y-axis direction (the left-right direction in FIG. 4A) is taken as the X-axis direction.

  A width dimension of the cable body 7 in the X-axis direction of the optical fiber cable 1 is formed to be substantially equal to a dimension of the cable support portion 13 in the X-axis direction.

  In the optical fiber cable 1, a center line in the X-axis direction passing through the axis of the optical fiber core wire 5 is located at a position corresponding to the optical fiber core wire 5 on both side surfaces in the X-axis direction of the cable body 7. Symmetrical deformation absorbing grooves 25A and 25B that are symmetrical in the Y-axis direction are formed symmetrically in the X-axis direction as the center. That is, the cable body 7 is configured symmetrically in the X-axis direction and the Y-axis direction with the optical fiber core wire 5 as the center.

  More specifically, in the present embodiment, the deformation absorbing grooves 25A, 25B are formed in an arc shape, and the intersections 27A, 27B, 27C, 27D of the cable body 7 with both surfaces in the X-axis direction are formed. The spacing dimension in the Y-axis direction is larger than the spacing dimension of the strength members 3, and the intersecting portions 27 </ b> A, 27 </ b> B, 27 </ b> C, and 27 </ b> D are located on both sides of the strength body 3 in the X-axis direction. . The bottom portions 29A and 29B of the deformation absorbing grooves 25A and 25B are located on both sides in the X-axis direction of the optical fiber core wire 5, and from the axis of the optical fiber core wire 5 to the bottom portions 29A and 29B. The distance L is formed to be larger than the radius of the optical fiber core wire 5 and smaller than the radius R of the support wire 11 provided in the cable support portion 13.

  In other words, when the optical fiber cable 1 is clamped by the P-clamp 17 similarly to the conventional optical fiber cable, the ceiling surface portion 19A and the gripper 21 of the clamp body 19 in the P-clamp 17 and the deformation absorbing groove 25A. 25B, the bottom portions 29A and 29B are not in contact with each other. That is, when the optical fiber cable 1 is clamped from the X-axis direction by the ceiling surface portion 19 </ b> A of the clamp body 19 and the gripper 21 in the P-clamp 17, the optical fiber core from both sides in the X-axis direction corresponding to the optical fiber core wire 5. In this configuration, a direct lateral pressure does not act on the wire 5.

  In the above configuration, when the optical fiber cable 1 is set and clamped on the P-clamp 17 described above, the cable support portion 13 and the cable body 7 in the optical fiber cable 1 are connected to the ceiling surface portion 19A of the clamp body 19 in the P-clamp 17. Both surfaces in the X-axis direction are clamped by the gripper 21. At this time, the cable body 7 is configured such that the end side in the Y-axis direction is pinched from the intersections 27A, 27B, 27C, and 27D between the deformation absorbing grooves 25A and 25B and both side surfaces in the X-axis direction. In other words, since the deformation absorption grooves 25A and 25B exist on both sides in the X-axis direction of the optical fiber core wire 5, both sides in the X-axis direction of the optical fiber core wire 5 receive a direct lateral pressure due to pinching. There is nothing.

  As described above, when both ends in the Y-axis direction of the cable support portion 13 and the cable body 7 are sandwiched from the X-axis direction by the ceiling surface portion 19A and the gripper 21 and firmly held, the cable support portion 13 and the cable body 7 The resin portion in is elastically deformed. At this time, the deformation of the resin portion in the cable body 7 is absorbed by the deformation absorbing grooves 25A and 25B, and the proximity position between the ceiling surface portion 19A and the gripper 21 is regulated by the support wire 11, and the deformation absorbing groove The bottom portions 29A and 29B of the 25A and 25B cannot contact each other. Therefore, since gaps exist between the bottom portions 29A and 29B of the deformation absorbing grooves 25A and 25B, the ceiling surface portion 19A, and the gripper 21, it is possible to suppress the occurrence of microbending in the optical fiber core wire 5. As described above, the conventional problems can be solved.

  By the way, the deformation absorbing grooves 25A and 25B on the both side surfaces in the X-axis direction of the cable body 7 cause the elastic deformation of the both ends when the both ends in the Y-axis direction of the cable body 7 are clamped from the X-axis direction. Any structure can be used as long as it absorbs and the gaps can exist in the bottom portions 29A and 29B, and the interval between the intersecting portions 27A, 27B, 27C, and 27D in the Y-axis direction is kept larger than the diameter of the optical fiber core wire 5. It is good. That is, the shape of the deformation absorbing grooves 25A and 25B is not limited to the circular arc shape as described above, but may be various shapes such as a triangular shape, a rectangular shape, and a polygonal shape.

  According to the above-described configuration, when the P-clamp 17 is clamped from the X-axis direction by the ceiling surface portion 19A of the clamp body 19 and the gripper 21, a plurality of cable support portions 13 and a plurality of cable body 7 on both ends in the Y-axis direction are arranged. Since the portion is pinched, the P-clamp 17 is stably clamped.

  By the way, the present invention is not limited to the above-described embodiments, and can be implemented in appropriate modifications. For example, as shown in FIG. 4B, it is also possible to form a V notch VN at the bottom of the deformation absorbing grooves 25A and 25B to form a V-shaped bottom so that the cable body 7 can be easily torn. In addition, the cable body 7 may be provided with connecting portions 9 and cable support portions 13 on both sides in the Y-axis direction so that the overall configuration of the optical fiber cable 1 is symmetrical with respect to the Y-axis direction and the X-axis direction. Is possible.

DESCRIPTION OF SYMBOLS 1 Optical fiber cable 3 Strength body 5 Optical fiber core wire 7 Cable main body 9 Connection part (neck part)
DESCRIPTION OF SYMBOLS 11 Support line 13 Cable support part 17 P-clamp 19 Clamp main body 21 Gripper 23 Wedge member 25A, 25B Deformation absorption groove 27A-27D Cross | intersection part 29A, 29B Bottom

Claims (2)

  A longitudinal direction of an optical fiber cable provided with a cable support portion via a connecting portion on one side of a cable body provided with an optical fiber core wire disposed between a pair of strength members, the tensile strength body, When the arrangement direction of the optical fiber core wire and the cable support portion is the Y-axis direction, and the direction orthogonal to the Z-axis direction and the Y-axis direction is the X-axis direction, the both sides of the cable body in the X-axis direction are A groove having a width wider than the diameter of the optical fiber core is provided at a position corresponding to the optical fiber core in the Z-axis direction, and a separation dimension from the axis of the optical fiber core to the bottom of the groove is: An optical fiber cable, wherein the optical fiber cable is larger than a radius of the optical fiber core wire and smaller than a radius of a support line provided in the cable support portion.   2. The optical fiber cable according to claim 1, wherein the bottom of the groove is formed in a V shape.

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