JP2011022229A - Optical fiber cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical fiber cable which ensures that two optical fibers are each taken out without being imbedded in a jacket and which facilitates identification of the two optical fibers, in exposing the optical fibers by removing the jacket. <P>SOLUTION: Two coated optical fibers 5 are covered integrally with a jacket 7, with the jacket 7 interposed between the two coated optical fibers 5. In the jacket 7, there are two notches 8 formed corresponding to the respective coated optical fibers 5. With respect to the optical fiber 5 on the other side further away from the notch 8 on one side, the deepest part 9 of the notch 8 on the one side is situated in a position farther away than the space A between the optical fibers. Also, on the outer side of the two coated optical fibers 5, two high-tensile wires 6 are arranged in parallel with the coated optical fibers 5 and covered with the jacket 7. The two high-tensile wires 6, relative to the respective coated optical fibers 5, are arranged in a position farther away than the space A between the coated optical fibers 5. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an optical fiber cable in which two optical fibers are integrally covered with a jacket.

  2. Description of the Related Art In a factory automation (FA) application in which devices are communicably connected such as connecting a control panel and a machine tool in a factory, a two-fiber type optical connector is widely used. In such an optical connector, it is common that a ferrule is provided for each optical fiber and the distance between the optical fibers is increased.

As an optical fiber cable that can be connected to such an optical connector, an indoor optical fiber cable having two optical fibers can be cited.
The two-core type indoor type optical fiber cable is arranged inside the jacket in a state where two optical fibers are in contact with each other in parallel (for example, see Patent Document 1).

JP 2006-30335 A

  When connecting an optical fiber to a two-fiber type optical connector used for FA, etc., use an ordinary indoor type optical fiber cable to reduce the cost and attach the optical connector by an automatic machine. It is preferable that In order to attach an optical connector to an indoor type optical fiber cable, first, the outer end of the cable end portion is removed to expose the optical fiber. Then, the exposed optical fiber is inserted into the ferrule of the optical connector, but it is necessary to identify which optical fiber is inserted into the two ferrules.

  However, since the conventional indoor optical fiber cable is in a state where two inner optical fibers are in contact with each other even if the outer sheath is torn from a notch formed in the outer sheath, the two optical fibers are in contact with each other. May not be separated into left and right and may be misplaced with respect to the ferrule. Moreover, even if the jacket is torn, the optical fiber is buried in the jacket and the optical fiber cannot be taken out.

  An object of the present invention is to provide an optical fiber cable in which two optical fibers can be reliably taken out without being buried in the outer sheath when the outer sheath is removed to expose the optical fiber, and the two can be easily identified. There is.

The optical fiber cable according to the present invention capable of solving the above-mentioned problems is an optical fiber cable in which two optical fibers are integrally covered with a jacket,
The jacket is interposed between the two optical fibers,
The jacket is formed with at least two notches corresponding to the optical fibers,
The deepest part of the notch on one side is located farther than the distance between the optical fibers with respect to the optical fiber on the other side far from the notch on one side.

In the optical fiber cable of the present invention, on the outside of the two optical fibers, two tensile wires arranged in parallel with the optical fiber are arranged so as to be covered by the jacket,
It is preferable that the two tensile strength lines are disposed at positions farther from the optical fibers than the distance between the optical fibers.

  In the optical fiber cable of the present invention, it is preferable that the deepest portion of each notch is located at a position closer to each optical fiber than the distance between the optical fibers.

According to the present invention, when the jacket is torn from the notch on one side, the tear reaches the optical fiber on one side. Further, when the outer cover is torn, the distance from the optical fiber on one side to the deepest part of the notch on the other side is larger than the distance between the optical fibers, so that the tear is directed from the optical fiber on one side to the optical fiber on the other side. Occurs. If a tear occurs from the optical fiber on one side to the notch on the other side, the optical fiber on the other side remains buried in the jacket. The fiber can be reliably taken out without being buried in the jacket.
Furthermore, since the two optical fibers are arranged at a distance from each other inside the jacket, it is easy to distinguish the two optical fibers even when they are exposed. When attaching an optical connector to this optical fiber cable, It is possible to prevent two optical fibers from being mixed up. Therefore, the optical connector can be attached by an automatic machine, and the efficiency and reliability of the attachment work are improved.

It is sectional drawing which shows the example of the optical fiber cable of this invention. It is the schematic which shows the process of attaching an optical connector to the optical fiber cable of FIG.

Hereinafter, an example of an embodiment of an optical fiber cable according to the present invention will be described with reference to the drawings.
As shown in FIG. 1, the optical fiber cable 1 includes two optical fiber cores (optical fibers) 5 and two tensile wires 6 that are integrally covered with a jacket 7. The tensile strength wires 6 are arranged side by side on both sides of the two optical fiber core wires 5 therebetween.

The optical fiber core 5 is preferably a plastic clad fiber (PCF) in which the core is quartz glass and the clad is a high-hardness plastic, and a coating such as an ultraviolet curable resin is provided around the core. The diameter of each part is, for example, 0.2 mm for the core, 0.23 mm for the cladding, and 0.35 mm for the coating.
The two optical fiber core wires 5 are arranged at a distance from each other, and an outer jacket 7 is interposed between them.

  As the tensile strength wire 6, a metal wire such as steel or GFRP (glass fiber reinforced plastic) can be used. An adhesive layer may be provided on the outer periphery of the tensile strength wire 6 in order to improve adhesion with the outer jacket 7. The outer diameter of the tensile strength wire 6 is 0.4 mm, for example, and the outer diameter of the adhesive layer is 0.56 mm, for example.

  The outer jacket 7 is made of a resin such as flame retardant polyethylene and has a substantially rectangular cross section that is long in the parallel direction of the optical fiber core wire 5 and the tensile strength wire 6. The dimension in the direction of the long side of the cross section is, for example, 4.2 mm, and the dimension in the direction of the short side of the cross section is, for example, 2.0 mm. Further, the corner portion of the outer cover 7 is chamfered to be a curved surface.

  A notch 8 having a V-shaped cross section is formed in each of the two long side portions of the jacket 7 corresponding to each optical fiber core wire 5. The deepest part 9 of the notch 8 is provided close to the optical fiber core wire 5.

Here, the distance between the two optical fiber core wires 5 and other parts will be described. One optical fiber core wire is designated as 5a, and a sign is attached to the side near this (left side in FIG. 1), and the other optical fiber core wire is designated as 5b, and the side closer to this (right side in FIG. 1). This will be described by adding b to the reference numeral.
The distance A between one optical fiber core wire 5a and the other optical fiber core wire 5b is about 0.4 mm. The distance B between one optical fiber core wire 5a and the deepest part 9a of one notch 8a is about 0.3 mm. The distance B between the other optical fiber core wire 5b and the deepest part 9b of the other notch 8b is also about 0.3 mm. The distance C between one optical fiber core wire 5a and the deepest part 9b of the other notch 8b is about 0.5 mm. The distance C between the other optical fiber core wire 5b and the deepest portion 9a of one notch 8a is also about 0.5 mm.

  Thus, one optical fiber core wire 5a is disposed at a position closest to the deepest portion 9a of one notch 8a. In addition, the other optical fiber core wire 5b is disposed at a position closest to the deepest portion 9b of the other notch 8b. Thereby, even if the jacket 7 is torn from any of the notches 8, the tear reaches the optical fiber core wire 5 which is closer.

  And the distance C from the deepest part 9a of one notch 8a to the other optical fiber core wire 5b is larger than the distance A between one optical fiber core wire 5a and the other optical fiber core wire 5b (A <C). . The distance C from the deepest part 9b of the other notch 8b to the one optical fiber core wire 5a is also larger than the distance A. As a result, the tear that reaches from one notch 8a to one optical fiber core 5a is directed to the other optical fiber core 5b without going to the other notch 8b, so that one optical fiber core 5a and the other optical fiber The jacket 7 is torn between the optical fiber 5b. Thereafter, the jacket 7 between the other optical fiber core wire 5b and the other notch 8b is torn.

  Thus, after the outer jacket 7 between one notch 8a and one optical fiber core 5a or the outer jacket 7 between the other notch 8b and the other optical fiber core 5b is torn, Further, when the outer sheath 7 is torn into two using the rigidity of the tensile strength wires 6a and 6b, the outer sheath 7 is torn between the one optical fiber core wire 5a and the other optical fiber core wire 5b. That is, in the optical fiber cable 1, when the outer cover 7 is torn into two from any notch 8, the outer cover 7 is torn at the locations indicated by the distances A and B, and the optical fiber core wires 5 a and 5 b are disconnected. 7 can be taken out without being buried.

  Further, the distance D between the one optical fiber core wire 5a and the one tensile strength wire 6a is longer than the distance A and the distance B. The distance D between the other optical fiber core wire 5b and the other tensile strength wire 6b is also longer than the distance A and the distance B. Therefore, when the outer sheath 7 is torn, the outer sheath 7 is prevented from being split between the notch 8a, 8b or the optical fiber core wires 5a, 5b and the tensile strength wires 6a, 6b. The optical fiber core wires 5a and 5b can be taken out.

  Further, the deepest portion 9a of one notch 8a is located closer to the one optical fiber core 5a than the distance A between the optical fiber cores 5a and 5b (distance A> B). Further, the other optical fiber core wire 5b is located at a position farther than the distance B from the one optical fiber core wire 5a with respect to the deepest portion 9a of one notch 8a (distance C> B). Thereby, the tear from one notch 8a formed when tearing the jacket 7 reaches not between the other optical fiber core 5b but between the one optical fiber core 5a. Similarly, the tear formed when tearing the jacket 7 from the other notch 8b reaches not between one optical fiber core 5a but the other optical fiber core 5b.

  When tearing the jacket 7, blades are arranged at the upper and lower positions in FIG. 1 at the end of the optical fiber cable 1 so that the blades enter the deepest portions 9 a and 9 b of the notches 8 a and 8 b, respectively. In this state, the optical fiber cable 1 and the blade may be slid relative to each other in the cable longitudinal direction. Thereby, a cut | interruption enters inside from the deepest part 9a, 9b, and the jacket 7 can be more reliably torn from the notches 8a, 8b to the optical fiber core wires 5a, 5b.

Next, the process of attaching an optical connector to the end of the optical fiber cable 1 will be described with reference to FIG.
When the outer fiber 7 is torn by a predetermined length of the terminal and the optical fiber core wire 5 is taken out, the outer sheath 7 and the tensile strength wire 6 at the torn part are cut and removed. That is, as shown in FIG. 2A, only the two optical fiber core wires 5 are exposed at the terminal portion. At this time, the optical fiber core wires 5 are arranged apart from each other as in the case where they are covered with the jacket 7.

As shown in FIG. 2A, the optical connector 20 has a configuration in which two ferrules 22 are provided in a housing 21. In an automatic machine for attaching an optical connector, a core wire separating pin 23 is arranged behind the housing 21 (right side in the figure), and the optical fiber cable 1 is set behind the pin.
Since the distance between the axes of the insertion holes of the two ferrules 22 is longer than the distance between the optical fiber cores 5, the automatic machine uses the core wire separation pin 23 to direct the optical fiber core wire 5 toward the ferrule 22. To guide.

As shown in FIG. 2 (b), when the optical fiber cable 1 is advanced toward the optical connector 20, the two optical fiber core wires 5 come into contact with the core wire separating pins 23 and the distance between them is increased. Guided towards 22 When the optical fiber cable 1 is further advanced as it is, the tips of the two optical fiber cores 5 are inserted into the ferrule 22, and the optical fiber core wire 5 reaches the position of the front end of the ferrule 22 as shown in FIG. Is inserted.
A guide member that guides the optical fiber core wire 5 toward the insertion hole of the ferrule 22 with higher accuracy may be provided between the ferrule 22 and the core wire separation pin 23.
And in order to make the front end surface of the ferrule 22 and the front end surface of the optical fiber core wire 5 coincide with each other with high accuracy, the optical fiber core wire 5 is once protruded in front of the ferrule 22, and then the optical fiber core is projected by the protrusion length. The line 5 may be cut.

  Thus, since the two optical fiber core wires 5 are separated and exposed when the jacket 7 is removed, the optical fiber cable 1 is clearly identified without the two optical fiber core wires 5 crossing each other. Thus, it is possible to prevent a misplacement with respect to the ferrule 22.

  DESCRIPTION OF SYMBOLS 1: Optical fiber cable, 5: Optical fiber core wire (optical fiber), 6: Tensile wire, 7: Outer sheath, 8: Notch, 9: The deepest part of a notch, 20: Optical connector, 21: Housing, 22: Ferrule

Claims (3)

An optical fiber cable in which two optical fibers are integrally covered with a jacket,
The jacket is interposed between the two optical fibers,
The jacket is formed with at least two notches corresponding to the optical fibers,
An optical fiber cable, wherein a deepest portion of the notch on one side is located farther than a distance between the optical fibers with respect to the optical fiber on the other side far from the notch on one side. The optical fiber cable according to claim 1,
Two tensile wires arranged in parallel with the optical fiber are arranged outside the two optical fibers so as to be covered with the outer sheath,
The optical fiber cable, wherein the two tensile strength lines are arranged at positions farther from the distance between the optical fibers than the optical fibers. The optical fiber cable according to claim 1 or 2,
An optical fiber cable, wherein a deepest portion of each notch is located at a position closer to each optical fiber than a distance between the optical fibers.

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