Optical cable and method of manufacturing an optical cable

Abstract

The present invention relates to an optical cable and a method of manufacturing the same. The optical cable (1) of the present invention is characterized by comprising a plurality of optical fiber units (11) each having an optical fiber bundle (14) composed of a plurality of optical fibers (15), and the plurality of optical fiber units (11) are stranded in an SZ shape, and at least one of the optical fiber bundles (14) has a clamping member (17) wound around the outer periphery thereof.

Description

Technical Field

[0001] This invention relates to optical cables and methods for manufacturing optical cables. Background Technology

[0002] It is known that an assembly of multiple optical fibers bundled together is called an optical fiber unit, and multiple optical fiber units are housed inside an outer sheath to form an optical cable. Patent Document 1 describes a technique in which, when multiple optical fiber units are twisted into an SZ shape, a clamping device is placed inside the compression tape surrounding the multiple optical fiber units in order to suppress the "untwisting" that causes the optical fibers to move in the direction of untwisting.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2020-76915

[0004] To suppress de-twisting, it is preferable to arrange more clamping material around the fiber unit to reduce voids within the optical cable. On the other hand, if the amount of clamping material within the optical cable increases, the lateral pressure applied to the fiber will increase, potentially increasing microbending loss. Therefore, it is desirable to address the opposite problem of reducing clamping material while suppressing de-twisting of the fiber unit. Summary of the Invention

[0005] The purpose of this invention is to reduce clamping material and suppress uncoupling.

[0006] The main invention for achieving the above objectives is an optical cable having multiple optical fiber units, each having an optical fiber bundle composed of multiple optical fibers, the multiple optical fiber units being twisted into an SZ shape, and at least one optical fiber bundle having a clamping component wound around its outer periphery.

[0007] Other features of the invention will become clear from the description in the following specification and drawings.

[0008] According to the present invention, it is possible to reduce the number of clamping components and suppress the untwisting of the optical fiber unit. Attached Figure Description

[0009] Figure 1 is an explanatory diagram of optical cable 1.

[0010] Figure 2A This is an explanatory diagram of fiber optic unit 11. Figure 2B This is an explanatory diagram of the other fiber optic units 11.

[0011] Figure 3 This is an explanatory diagram of the configuration of the clamping component 17A of a certain optical fiber unit 11A.

[0012] Figure 4 This is a table representing the evaluation results of the disassembly operability of optical cable 1.

[0013] Figure 5 This is an explanatory diagram of the manufacturing system 40 for optical cable 1.

[0014] Figure 6A as well as Figure 6B This is an explanatory diagram of panel 44.

[0015] Figures 7A to 7C This is an explanatory diagram showing the situation when panel 44 is rotated.

[0016] Figure 8 This is an explanatory diagram of the manufacturing system 40 in the modified example.

[0017] Figure 9A This is an explanatory diagram illustrating the measurement of the compressibility R. Figure 9B This is an illustrative diagram showing the change in cross-sectional shape before and after the application of lateral pressure.

[0018] Figure 10 It is the result of the measurement of the compression ratio of the clamping components, bundle materials, and Kevlar fibers.

[0019] Figure 11 It is a graph showing the relationship between the applied load P and the compression ratio R.

[0020] Figure 12 This is a cross-sectional diagram illustrating the clamping component 17 inside the optical cable 1. Detailed Implementation

[0021] Based on the description in the following instructions and the accompanying drawings, at least the following will become clear.

[0022] An optical cable is disclosed comprising multiple optical fiber units having optical fiber bundles composed of multiple optical fibers, the multiple optical fiber units being twisted into an SZ shape, and at least one optical fiber bundle having a clamping member wound around its outer periphery. According to such an optical cable, the number of clamping members can be reduced and the untwisting of the optical fiber units can be suppressed.

[0023] Preferably, the aforementioned optical fiber unit includes a bundle for bundling the multiple optical fibers. This allows the optical fibers to be bundled together without becoming tangled.

[0024] Preferably, the aforementioned clamping component is wound around the outside of the aforementioned bundle material. This allows the clamping component to easily contact the surrounding fiber optic units, thus reducing the number of clamping components and further suppressing the untwisting of the fiber optic units.

[0025] Preferably, the fiber optic unit includes both the fiber optic unit with the aforementioned clamping component and the fiber optic unit without the aforementioned clamping component. This makes it easier to reduce the number of clamping components.

[0026] Preferably, the inner layer unit is composed of the aforementioned optical fiber units, and the outer layer unit is composed of a plurality of the aforementioned optical fiber units arranged circumferentially on the outside of the inner layer unit. The optical fiber units constituting the inner layer unit have the aforementioned clamping member. Furthermore, in this case, it is preferable that the outer layer unit includes: optical fiber units having the aforementioned clamping member, and optical fiber units without the aforementioned clamping member. This reduces the number of clamping members and further suppresses the untwisting of the optical fiber units.

[0027] Preferably, an optical fiber unit without the clamping component is disposed between two optical fiber units having the clamping component in the outer layer unit. This reduces the number of clamping components and further suppresses the untwisting of the optical fiber unit.

[0028] When the winding spacing of the aforementioned clamping components is set to P1, and the twisting spacing of the plurality of aforementioned optical fiber units is set to P2, it is preferable that P1 / P2 is 0.1 or higher. This improves the ease of disassembling the optical cable.

[0029] Preferably, the aforementioned clamping component is not connected to other components and is wound in an SZ shape around the outer periphery of the fiber bundle. The clamping component does not need to bundle multiple fibers, so it can be wound in an SZ shape around the outer periphery of the fiber bundle without connecting to other components.

[0030] When the load applied to the winding member that is wound around the outer periphery of the clamping member is set to P (N), and the compression ratio of the clamping member when the load P is applied to the winding member and lateral pressure is added to the clamping member is set to R, it is preferable that when the load P is 1N or more, the compression ratio R increases as the load P increases. This helps to suppress the untwisting of the optical fiber unit.

[0031] Preferably, when the load P is in the range of 1.5 to 2.0 N, the compression ratio R increases as the load P increases. This helps to suppress the de-twisting of the fiber unit.

[0032] Preferably, the ratio of the increase in the compression ratio R to the increase in the load P when the load P is in the range of 1.5 to 2.0 N is set as α(N). -1 When α is greater than 0.17, it can suppress the de-twisting of the fiber unit.

[0033] Preferably, when the load applied to the winding member that is wound around the outer periphery of the clamping member is set to P (N), and the compression ratio of the clamping member when the load P is applied to the winding member and lateral pressure is added to the clamping member is set to R, the clamping object can deform to a compression ratio R of 0.57 or higher. This suppresses the untwisting of the optical fiber unit.

[0034] A method for manufacturing an optical cable is disclosed, comprising the following steps: inserting an optical fiber bundle into each of a plurality of through holes in a panel; inserting a clamping member into at least one of the through holes in the panel; and winding the clamping member around the outer periphery of at least one of the optical fiber bundles by oscillating the panel. According to this method, it is possible to manufacture an optical cable with fewer clamping members and to suppress untwisting of the optical fiber units.

[0035] ===First Implementation Method===

[0036] <Structure of Optical Cable 1>

[0037] Figure 1A as well as Figure 1B This is an explanatory diagram of optical cable 1. For ease of explanation, the following diagrams will sometimes be used as follows: Figure 1B The fiber unit 11 with a deformed cross-sectional shape as shown is as follows: Figure 1A It is represented as a circular cross-section, as shown. Similarly, sometimes it is... Figure 1B The clamping component 17, which has a deformed cross-sectional shape as shown, is represented by a regular cross-section such as a circle or an ellipse.

[0038] Optical cable 1 is a cable that houses optical fibers. In this embodiment, optical cable 1 is an optical cable without slotted rods forming grooves (grooves for housing optical fibers), and is a so-called slotless optical cable. However, optical cable 1 can also be a slotted optical cable with slotted rods. Optical cable 1 has a core 10 and an outer sheath 20.

[0039] Core 10 is a component housed within the outer sheath 20. Core 10 has multiple fiber units 11 (11A~11J) and a compression tape 18. For example... Figure 1A (or Figure 1B As shown, although the core 10 of this embodiment has 10 optical fiber units 11, the number of optical fiber units 11 is not limited to 10. Furthermore, the core 10 of this embodiment is constructed by twisting multiple optical fiber units 11 into an SZ shape. The compression tape 18 is a component that surrounds the multiple optical fiber units 11.

[0040] In this embodiment, an inner layer unit 12 and an outer layer unit 13 are formed by multiple fiber optic units 11 constituting the core 10. The inner layer unit 12 is a fiber optic unit 11 disposed in the central part of the core 10. The outer layer unit 13 is a fiber optic unit 11 disposed outside the inner layer unit 12. In this embodiment, the inner layer unit 12 is composed of three fiber optic units 11, and the outer layer unit 13 is composed of seven fiber optic units 11. However, the number of fiber optic units 11 constituting the inner layer unit 12 and the outer layer unit 13 is not limited to these. In the following description, letters A to C are sometimes added to the reference numerals of the fiber optic units 11 constituting the inner layer unit 12, and letters D to J are sometimes added to the reference numerals of the fiber optic units 11 constituting the outer layer unit 13. In addition, in the following description, it is preferable to add the same letters as the corresponding fiber optic units 11 to the reference numerals of the components corresponding to the fiber optic units 11 (e.g., the insertion hole 441 in FIG. 7).

[0041] The outer sheath 20 is a component that covers multiple optical fiber units 11 (and the coiled tape 18). Although the cross-section of the outer sheath 20 is approximately circular, its shape is not limited to a circular shape. Tension members 21 are embedded in the outer sheath 20. In addition to tension members 21, other components (such as tear cords 22) may also be embedded in the outer sheath 20.

[0042] Figure 2A This is an explanatory diagram of fiber optic unit 11.

[0043] The optical fiber unit 11 is a structure that bundles together multiple optical fibers 15. Figure 2A The fiber unit 11 shown has a fiber bundle 14 and a bundle 16. The fiber bundle 14 is a bundle of multiple optical fibers 15. In this embodiment, the fiber bundle 14 is formed by bundling multiple intermittently connected fiber ribbons. However, the fiber bundle 14 may not be composed of multiple intermittently connected fiber ribbons; for example, it may be composed of a single intermittently connected fiber ribbon, or it may be composed of multiple single-core optical fibers. The bundle 16 is a component that bundles the multiple optical fibers 15 constituting the fiber bundle 14. The bundle 16 is wound around the outer periphery of the fiber bundle 14. This bundles the multiple optical fibers 15 constituting the fiber bundle 14 in a non-scattered manner. In this embodiment, the fiber unit 11 has a pair of bundles 16, each bundle 16 wound in an SZ shape around the outer periphery of the fiber bundle 14 with opposite winding directions at the junction. The bundle 16 is not limited to being wound in an SZ shape; it may also be wound in a spiral shape along one direction around the outer periphery of the fiber bundle 14. Furthermore, the number of bundles 16 is not limited to two. In addition, when the fiber unit 11 is composed of an intermittently connected fiber ribbon, the fiber unit 11 may not have a bundle material 16 because the bundle of fiber 15 will not be scattered.

[0044] Figure 2B This is an explanatory diagram of the other fiber optic units 11.

[0045] Several fiber optic units 11 (11A-11C, 11G, 11J) in this embodiment; refer to Figure 1A It also has a clamping component 17.

[0046] The clamping component 17 is a component that fills the gaps in the internal space of the optical cable 1. By arranging the clamping component 17 inside the optical cable 1, the installation density of the optical fibers 15 can be increased. Furthermore, the installation density of the optical fibers 15 is the ratio of the cross-sectional area of ​​the multiple optical fibers 15 to the area of ​​the components other than the optical fibers 15 (such as the compression tape 18, the bundle 16, and the clamping component 17) after removing the overall cross-sectional area from the internal space of the optical cable 1. That is, when the overall cross-sectional area of ​​the internal space of the optical cable 1 is set as S0, the total cross-sectional area of ​​the components other than the optical fibers 15 inside the optical cable 1 (such as the compression tape 18, the bundle 16, and the clamping component 17) is set as S1, the total cross-sectional area of ​​the optical fibers 15 inside the optical cable 1 is set as Sf, and the installation density of the optical fibers 15 is set as ρ, then ρ = Sf / (S0 - S1).

[0047] However, when the installation density of optical fiber 15 is low, the increased gaps within the internal space of optical cable 1 may cause the multiple stranded SZ-shaped optical fiber units 11 to shift towards eliminating the stranding. That is, with a low installation density of optical fiber 15, there is a concern about "untwisting" of the optical fiber units 11. On the other hand, to suppress "untwisting," excessively increasing the number of clamping components 17 disposed within the optical cable 1 could increase the lateral pressure applied to the optical fiber 15, leading to increased microbending loss. In particular, low-loss optical fibers (e.g., optical fibers with low-loss characteristics conforming to ITU-T G.654.E) used to increase the transmission range of optical cable 1 have poorer microbending characteristics compared to optical fibers conforming to ITU-T G.657.A1. Therefore, if more clamping components 17 are disposed within the optical cable 1 using such optical fibers, microbending loss is likely to increase. Therefore, in this embodiment, as described below, the number of clamping components 17 is reduced, and "untwisting" of the optical fiber units 11 is suppressed.

[0048] The clamping component 17 in this embodiment is a long strip-shaped component, wound around the outer periphery of the optical fiber bundle 14 in a spiral or SZ shape along its long side. Although the clamping component 17 in this embodiment is a rope-like component, it is not limited to a rope shape; for example, it could also be a strip. Furthermore, although the clamping component 17 in this embodiment is made of a polypropylene rope, the material of the clamping component 17 is not limited to polypropylene and could be other materials. For example, the clamping component 17 could also be a water-absorbing component, such as absorbent yarn. The clamping component 17's water absorption property thereby inhibits water seepage into the optical cable 1. Figure 2BIn this configuration, the clamping component 17 is wound in a spiral shape around the outer periphery of the fiber bundle 14 in one direction. Alternatively, the clamping component 17 can be wound in an SZ shape around the outer periphery of the fiber bundle 14 by reversing the winding direction midway.

[0049] The preferred clamping component 17 is a component with cushioning properties compared to the bundle 16. Therefore, the clamping component 17 is a component whose cross-sectional shape changes significantly when lateral pressure is applied (in contrast, the bundle 16 is a component with a small amount of deformation whose cross-sectional shape hardly deforms even when lateral pressure is applied). In addition, the clamping component 17 deforms its cross-sectional shape even under small lateral pressure and has the property of easily restoring its cross-sectional shape when the lateral pressure is removed (high recovery rate). The clamping component 17 has such cushioning properties that even if the internal space of the optical cable 1 deforms when the cable is bent, it can continue to fill the gaps inside the optical cable 1 by following the deformation of the internal space. As a result, the orientation of the components (e.g., fiber unit 11) inside the optical cable 1 can be maintained, and the "un-twisting" of the fiber unit 11 can be suppressed.

[0050] In addition, Figure 2B In the original description, the fiber optic unit 11 (and fiber optic bundle 14) is depicted extending in a straight line along its long side. However, in this embodiment, since multiple fiber optic units 11 are twisted together inside the optical cable 1, the fiber optic unit 11 extends in an SZ shape along the long side of the optical cable 1. That is, the fiber optic unit 11 (and fiber optic bundle 14) is arranged in an SZ shape along the long side of the optical cable 1. In this embodiment, the clamping member 17 is wound in a spiral or SZ shape along the long side of such an SZ-shaped fiber optic bundle 14.

[0051] Figure 3 This is an explanatory diagram illustrating the configuration of the clamping component 17A of a certain optical fiber unit 11A. Only the clamping component 17A of the optical fiber unit 11A is shown here; the clamping components 17 of other optical fiber units 11 are not illustrated. Figure 3 The image shows cross-sections of optical cable 1 at different locations along its long side. Furthermore, in... Figure 3 In this embodiment, the optical fiber units 11 inside the optical cable 1 are depicted in such a way that the circumferential position of the cross-section of the optical cable 1 is changed (in this embodiment, multiple optical fiber units 11 are twisted in an SZ shape inside the optical cable 1, so the position of the optical fiber units 11 in the cross-section of the optical cable 1 is different depending on the position of the long side of the optical cable 1).

[0052] In this embodiment, the clamping member 17 is wound around the outer periphery of the fiber bundle 14 in a spiral or SZ shape along the long side (see reference). Figure 2B Therefore, as Figure 3As shown, the clamping component 17A of a certain optical fiber unit 11A is not only adjacent to the specific optical fiber unit 11, but can also be adjacent to other surrounding optical fiber units 11. For example, Figure 3 The clamping component 17A of a certain optical fiber unit 11A shown is adjacent to the optical fiber unit 11D of the outer unit 13 in one cross-section, and adjacent to the optical fiber unit 11B of the inner unit 12 in another cross-section. Thus, Figure 3 The clamping component 17A of a certain fiber unit 11A shown is adjacent to multiple different fiber units 11. Similarly, the clamping components 17 of other fiber units 11 are also wound in a spiral or SZ shape around the outer periphery of the fiber bundle 14 along the long side, thereby adjacent to multiple different fiber units 11. In this way, the clamping component 17 of a certain fiber unit 11 is adjacent to multiple different surrounding fiber units 11, thus the clamping component 17 is adjacent to a large number of fiber units 11. The fiber units 11 adjacent to the clamping component 17 are easily held in a certain position by the clamping component 17 (twisted into an SZ shape), thus the clamping component 17 is adjacent to a large number of fiber units 11, thereby suppressing the "untwisting" of the fiber units 11. That is, in this embodiment, the clamping component 17 is wound in a spiral or SZ shape around the outer periphery of the fiber bundle 14 along the long side, thereby reducing the number of clamping components 17 and suppressing the "untwisting" of the fiber units 11.

[0053] In addition, in this embodiment, such as Figure 2B As shown, the clamping member 17 is wound around the outside of the bundle 16. Therefore, in this embodiment, compared with the case where the clamping member 17 is disposed on the inside of the bundle 16, the clamping member 17 can easily contact the surrounding fiber units 11, thus further suppressing the "untwisting" of the fiber units 11.

[0054] like Figure 1A As shown, in this embodiment, not all fiber optic units 11 have the clamping component 17, but fiber optic units 11 (11A-11C, 11G, 11J; see reference 11) have the clamping component 17. Figure 2B ), and fiber optic units 11 (11D~11F, 11H, 11I) without clamping components 17; see reference Figure 2A (The optical fibers are mixed together.) Therefore, compared to the case where all optical fiber units 11 have clamping components 17, the number of clamping components 17 inside the optical cable 1 can be reduced. Furthermore, by having optical fiber units 11 without clamping components 17 adjacent to the clamping components 17 of adjacent optical fiber units 11 to suppress "un-twisting", it is permissible for optical fiber units 11 without clamping components 17 to coexist. Alternatively, all optical fiber units 11 may have clamping components 17.

[0055] In addition, in this embodiment, such as Figure 1AAs shown, each of the three fiber optic units 11 (11A to 11C) constituting the inner unit 12 has a clamping member 17. Compared to the fiber optic units 11 (11D to 11J) constituting the outer unit 13, the inner unit 12 has a larger number of adjacent fiber optic units 11. Therefore, as in this embodiment, by having clamping members 17 on the fiber optic units 11 constituting the inner unit 12, the clamping members 17 are positioned adjacent to a larger number of fiber optic units 11. As a result, the fiber optic units 11 are more likely to maintain a twisted SZ shape, thus easily suppressing the "untwisting" of the fiber optic units 11. Alternatively, the fiber optic units 11 constituting the inner unit 12 may not have clamping members 17.

[0056] Moreover, in this embodiment, such as Figure 1A As shown, the outer unit 13 contains both fiber optic units 11 with clamping components 17 and fiber optic units 11 without clamping components 17. This reduces the number of clamping components 17 inside the optical cable 1. Furthermore, in this embodiment, even when the fiber optic units 11 of the inner unit 12 have clamping components 17, if the outer unit 13 contains fiber optic units 11 without clamping components 17, the fiber optic units 11 of the outer unit 13 are at least adjacent to the clamping components 17 of the fiber optic units 11 of the inner unit 12, thus suppressing the "untwisting" of the fiber optic units 11 of the outer unit 13.

[0057] Furthermore, when fiber optic units 11 with clamping components 17 and fiber optic units 11 without clamping components 17 coexist in the outer unit 13, it is preferable to arrange the fiber optic unit 11 without clamping components 17 between the two fiber optic units 11 with clamping components 17 in the circumferential direction. Thus, compared to the case where two fiber optic units 11 with clamping components 17 are adjacent in the circumferential direction in the outer unit 13, it is easier to suppress the "untwisting" of the fiber optic units 11 even if the number of clamping components 17 inside the optical cable 1 is reduced.

[0058] However, when the clamping component 17 is wound around the fiber bundle 14, if the winding pitch of the clamping component 17 is too narrow, the removal of the clamping component 17 becomes laborious and time-consuming, raising concerns about the time spent on branching the optical cable 1. Therefore, the winding pitch of the clamping component 17 is set to P1, and the twisting pitch of the multiple fiber units 11 is set to P2. Multiple types of optical cables 1 with varying P1 / P2 are manufactured, and the disassembly operability of each optical cable 1 is evaluated. Furthermore, the winding pitch P1 of the clamping component 17 is the length of the long side of the fiber bundle 14 when the clamping component 17, wound spirally around the outer circumference of the fiber bundle 14, completes one circumferential turn. The twisting pitch P2 is the length of the long side of the optical cable 1 from the start of the reverse twisting direction of the twisted SZ-shaped fiber units 11 until the next reverse twisting direction. The manufactured optical cable 1 is... Figure 1A (or Figure 1B The structure shown is composed of five four-core intermittently connected fiber optic ribbons forming fiber unit 11, and ten fiber units 11 are twisted together in an SZ shape. Furthermore, a clamping member 17 is spirally wound around five of the ten fiber units 11. Based on the disassembly operability of the optical cable 1 when the clamping member 17 is added longitudinally to the fiber bundle 14 without winding (making P1 infinitely large), the following criteria were used to evaluate the disassembly operability: "Excellent" (◎) indicates almost no change in disassembly operability; "Good" (〇) indicates no problem with disassembly operability; and "Acceptable" (△) indicates that disassembly is possible but takes time.

[0059] Figure 4 This is a table showing the evaluation results of the operability of disassembling optical cable 1. As shown in the figure, it is preferable that P1 / P2 is 0.1 or more (P1 / P2≥0.1). Furthermore, it is more preferable that P1 / P2 is 0.5 or more (P1 / P2≥0.5).

[0060] Alternatively, instead of spirally winding the clamping member 17 around the outer periphery of the fiber bundle 14, the clamping member 17 can be wound in an SZ shape around the outer periphery of the fiber bundle 14. When the clamping member 17 is wound in an SZ shape around the outer periphery of the fiber bundle 14, the removal of the clamping member 17 becomes easier compared to the spiral winding method. Furthermore, it is preferable that the clamping member 17 is not engaged with other components (e.g., another clamping member 17 in the case where the fiber unit 11 has two or more clamping members 17), but is wound in an SZ shape around the outer periphery of the fiber bundle 14. This makes the removal of the clamping member 17 easier. Moreover, unlike the bundle material 16, the clamping member 17 does not need to bundle multiple fibers 15, so it can be wound in an SZ shape around the outer periphery of the fiber bundle 14 to form the fiber unit 11 without being engaged with other components. Furthermore, unlike the bundle 16, the clamping component 17 does not need to bundle multiple optical fibers 15. Therefore, the number of clamping components 17 winding around the outer periphery of the optical fiber bundle 14 of the optical fiber unit 11 can be set to one, and this one optical fiber bundle 14 can be wound around the outer periphery of the optical fiber bundle 14 in an SZ shape. When the bundle 16 is wound in an SZ shape, it bundles multiple optical fibers 15 and thus joins with other bundles 16 in pairs. In contrast, even when the clamping component 17 is wound in an SZ shape, the number of clamping components 17 contained in the optical cable 1 can be set to one, thus easily suppressing the number of clamping components 17 contained in the optical cable 1.

[0061] As described above, the optical cable 1 of this embodiment includes a plurality of optical fiber units 11, each optical fiber unit 11 having an optical fiber bundle 14 composed of a plurality of optical fibers 15. The plurality of optical fiber units 11 are twisted into an SZ shape, and a clamping member 17 is wound around the outer periphery of at least one optical fiber bundle 14. According to the optical cable 1 with this structure, as... Figure 3 As shown, the clamping member 17 can be adjacent to multiple different fiber units 11. Therefore, the fiber units 11 adjacent to the clamping member 17 are easily held in an SZ-shaped twisted position by the clamping member 17. As a result, the number of clamping members 17 can be reduced and the "untwisting" of the fiber units 11 can be suppressed. Furthermore, in the above embodiment, each of the five fiber units 11 has a clamping member 17, but as long as at least one of the multiple fiber units 11 has a clamping member 17, and this clamping member 17 is wound around the outer periphery of the fiber bundle 14, the number of clamping members 17 can be reduced and the "untwisting" of the fiber units 11 can be suppressed.

[0062] <Manufacturing Method>

[0063] Figure 5 This is an explanatory diagram of the manufacturing system 40 for optical cable 1. The manufacturing system 40 includes: an optical fiber supply unit 41, a bundling device 42, a clamping supply unit 43, a panel 44, an extrusion molding unit 45, and a winding unit 47.

[0064] The optical fiber supply unit 41 is a device (supply source) for supplying optical fibers 15. In this embodiment, the optical fiber supply unit 41 is a device (supply source) for supplying intermittently connected optical fiber ribbons, capable of supplying multiple optical fibers 15. Specifically, the optical fiber supply unit 41 is composed of a spool (or reel) pre-wound with intermittently connected optical fiber ribbons. Alternatively, the optical fiber supply unit 41 may also be composed of an intermittently connected optical fiber ribbon manufacturing apparatus. In this embodiment, the optical fiber ribbon supplied from the optical fiber supply unit 41 is supplied to the bundling device 42 as an optical fiber bundle 14.

[0065] The bundling device 42 is a device for winding the bundle 16 around the outer periphery of the fiber bundle 14. In this embodiment, the bundling device 42 winds two bundles 16 in opposite directions into an SZ shape, and joins the two bundles 16 at the reverse position of the winding direction. Alternatively, the bundling device 42 may wind the bundle 16 in a spiral shape around the outer periphery of the fiber bundle 14 in one direction. The bundling device 42 winds the bundle 16 around the fiber bundle 14, thereby forming... Figure 2A The fiber optic unit 11 is shown. Furthermore, if the fiber optic unit 11 is constructed without the bundle 16, the bundling device 42 may also be omitted.

[0066] The clamping supply unit 43 is a device (supply source) for supplying the clamping component 17. For example, the clamping supply unit 43 is composed of a spool (or roll) with the clamping component 17 pre-wound.

[0067] Figure 6A as well as Figure 6B This is an explanatory diagram of panel 44. Figure 6A This is an explanatory diagram of panel 44. Figure 6B This is an explanatory diagram showing the state in which the fiber unit 11 (fiber bundle 14 and bundle material 16) and the clamping component 17 are inserted into the insertion hole 441 of the panel 44.

[0068] The panel 44 is a plate-shaped component having multiple insertion holes 441. Each insertion hole 441 is a through-hole extending through the panel 44, used for inserting the fiber bundle 14 and the clamping member 17. In this embodiment, the insertion holes 441 are circular. Fiber units 11 (fiber bundles 14) are supplied from the bundling device 42 toward their respective insertion holes 441 in the panel 44, and clamping members 17 are supplied from the clamping supply unit 43. Figure 5 As shown, the supply direction of the optical fiber unit 11 to the panel 44 is different from the supply direction of the clamping component 17. Specifically, the supply direction of the optical fiber unit 11 to the panel 44 is approximately perpendicular to the panel 44, while the supply direction of the clamping component 17 to the panel 44 is inclined relative to the perpendicular direction of the panel 44.

[0069] With the fiber bundle 14 and the clamping member 17 inserted into the insertion hole 441, the insert 44 oscillates around its central rotation axis. This oscillation of the insert 44 strands multiple fiber units 11 into an SZ shape. Furthermore, the oscillation of the insert 44 in this embodiment also functions to arrange the clamping member 17 in an SZ shape around the outer periphery of the fiber bundle 14.

[0070] Figures 7A to 7C This is an explanatory diagram showing the situation when the panel 44 is rotated. For illustration, the diagram here shows the state where the fiber bundle 14 and the clamping component 17A are inserted into only one insertion hole 441A.

[0071] like Figures 7A to 7C As shown, the panel 44 is oscillated, thereby changing the circumferential position of the fiber bundle 14. As a result, inside the optical cable 1, the fiber bundle 14 (fiber unit 11A) is arranged in an SZ shape along the long side direction.

[0072] As already explained, in this embodiment, the clamping member 17 is inclined relative to the vertical direction of the insert 44 in the supply direction toward the insert 44. As a result, the clamping member 17 is easily biased towards the clamping supply section 43 side inside the through hole 441. For example, Figures 7A to 7C The clamping supply section 43 of the clamping component 17 shown (see reference) Figure 5 The panel 44 is positioned on the upper side of the insertion hole 441 in the figure, resulting in: Figures 7A to 7C The clamping member 17A shown is located inside the insertion hole 441A and is easily biased towards the upper side (upper edge) of the insertion hole 441. In this embodiment, the panel 44 is swung while the clamping member 17 is biased towards the insertion hole 441 in a specific direction, thereby allowing the clamping member 17 to be wound around the outer periphery of the fiber bundle 14 in an SZ shape along the long side direction.

[0073] Furthermore, in this embodiment, the through hole 441 is configured as a circle. Thus, as... Figures 7A to 7C As shown, when the panel 44 is oscillating, the fiber bundle 14 and the clamping member 17 can easily slide circumferentially (along the periphery of the insertion hole 441) with respect to the periphery of the insertion hole 441, and the clamping member 17 can easily be biased in a specific direction (here, the upper side) inside the insertion hole 441. Since the clamping member 17 can be biased in a specific direction inside the insertion hole 441, the shape of the insertion hole 441 does not have to be circular; it can be any other shape.

[0074] Furthermore, in this embodiment, the panel 44 is oscillated while the clamping member 17 is positioned biased in a specific direction inside the insertion hole 441. This allows the clamping member 17 to not only abut against a specific fiber optic unit 11 but also against other surrounding fiber optic units 11. For example, Figure 7A The clamping component 17A shown is in Figure 7B In the state shown, the fiber optic unit 11D inserted into the insertion hole 441D (in) Figure 7B Not illustrated in the image; see reference. Figure 3 Adjacent, in Figure 7C In the state shown, the fiber optic unit 11B inserted into the insertion hole 441B (in) Figure 7C Not illustrated in the image; see reference. Figure 3 Similarly, by swinging the panel 44 while the clamping member 17, which is inserted into other through holes 441, is biased in a specific direction inside the through hole 441, it is also possible to be adjacent to multiple different fiber optic units 11.

[0075] like Figure 5 As shown, multiple optical fiber units 11, after passing through the panel 44, are supplied to the extrusion molding section 45 in an SZ-shaped stranded state. In addition to supplying multiple optical fiber units 11 to the extrusion molding section 45, other components such as compression tape 18, tension member 21, and tear cord 22 are also supplied.

[0076] The extrusion molding section 45 is an apparatus for forming the outer sheath 20. In the extrusion molding section 45, a compression tape 18 is wound around multiple optical fiber units 11, and resin that will become the outer sheath 20 is extruded and molded, thereby manufacturing the outer sheath 20. Figure 1A (or Figure 1B The optical cable 1 of this embodiment is shown in the figure. After being cooled by the cooling device 46, the optical cable 1 manufactured by the extrusion molding section 45 is wound onto the winding section 47 (e.g., a spool).

[0077] As described above, in the manufacturing method of the optical cable 1 of this embodiment, the following steps are performed: inserting the optical fiber bundle 14 into each of the plurality of insertion holes 441 of the panel 44; inserting the clamping member 17 into at least one insertion hole 441 of the panel 44; and winding the clamping member 17 around the outer periphery of at least one optical fiber bundle 14 by swinging the panel 44. According to this manufacturing method, it is possible to manufacture an optical cable 1 that can reduce the number of clamping members 17 and suppress the "untwisting" of the optical fiber unit 11.

[0078] Figure 8 This is an explanatory diagram of the manufacturing system 40 of the modified example. The manufacturing system 40 of the modified example includes an optical fiber supply unit 41, a bundling device 42, a clamping and winding unit 43', a panel 44, an extrusion molding unit 45, and a winding unit 47. Figure 5 Compared to the manufacturing system 40 shown, the modified manufacturing system 40 replaces the aforementioned clamping supply unit 43 (see reference). Figure 5The device has a clamping and winding section 43'. The clamping and winding section 43' is a device for winding the clamping member 17 around the outer periphery of the fiber bundle 14. Here, the clamping and winding section 43' is a device for winding the clamping member 17 around the outer periphery of the fiber bundle 14 in a spiral shape. Alternatively, if the clamping member 17 does not fall off, it can also be wound around the outer periphery of the fiber bundle 14 in an SZ shape.

[0079] In a modified example, the insert 44, with the fiber bundle 14 and the clamping member 17 inserted into the insertion hole 441, swings around its central rotation axis. This swinging motion of the insert 44 twists multiple fiber units 11 into an SZ shape. In another modified example, the clamping member 17 is wound around the outer periphery of the fiber bundle 14 in a spiral or SZ shape, thereby twisting multiple fiber units 11 into an SZ shape. Therefore, in this modified example, the winding pitch P1 of the clamping member 17 and the twisting pitch P2 of the multiple fiber units 11 can be easily set separately.

[0080] <Regarding the cushioning of clamping component 17>

[0081] As already explained, clamping component 17 is a component whose cross-sectional shape changes significantly when lateral pressure is applied. As an example of an indicator of the change in cross-sectional shape when lateral pressure is applied, there is a compression ratio. When the diameter of the component before lateral pressure is applied is set to D1 (mm), and the diameter of the component when lateral pressure is applied is set to D2 (mm), the compression ratio R of the component is as shown in the following formula.

[0082] R = (D1 - D2) / D2

[0083] Furthermore, when the length of the outer perimeter of the component before lateral pressure is applied (initial circumference) is set to L1 (mm), and the length of the outer perimeter of the component when lateral pressure is applied is set to L2 (mm), the compression ratio R of the component is as shown in the following formula.

[0084] R = (L1 - L2) / L2

[0085] Figure 9A This is an explanatory diagram illustrating the measurement of the compressibility R. Figure 9B This is an illustrative diagram showing the change in cross-sectional shape before and after the application of lateral pressure.

[0086] like Figure 9A As shown, one end of the component 19 to be measured (e.g., clamping component 17) is fixed, and a weight is installed at the other end to apply tension to the component 19. Here, a weight of 200g (approximately 2N of tension) is applied in the same manner as the clamping component 17 in the optical cable 1.

[0087] Figure 9B The left side shows the state before the load is applied to the winding component 53. Figure 9BThe right side shows the state in which a load is applied to the winding component 53.

[0088] like Figure 9A as well as Figure 9B As shown, a rope-like winding member 53 is wound around the outer periphery of the component being measured 19 (e.g., clamping component 17). Additionally, as... Figure 9A as well as Figure 9B As shown, one end of the component 19 being measured is fixed, and a measuring device 52 is mounted on the other end. The measuring device 52 measures the load P (N) applied to the winding component 53, and the displacement X (mm) of the end of the winding component 53 relative to the reference position X0.

[0089] like Figure 9A As shown, at the reference position X0 before applying a load to the winding component 53, the initial circumference of the component 19 being measured is L1, and the diameter is D1. Figure 9B As shown, if a load P (pull load) is applied to the winding component 53, lateral pressure is applied evenly to the outer periphery of the component being measured 19, and the cross-sectional shape of the component being measured 19 is compressed and deformed, the circumference of the component being measured 19 becomes L2, and the diameter becomes D2 (the density of the component being measured 19 increases). Figure 9B As shown, if a load is applied to the winding member 53, the end of the winding member 53 will be displaced. By measuring the displacement X of the end of the winding member 53 relative to the reference position X0 with the measuring device 52, the circumference L2 (or diameter D2) of the measured member 19 can be measured, and thus the compression ratio R can be calculated.

[0090] Figure 10 These are the results of measurements on the compression ratios of the clamping components, bundles, and Kevlar fibers. Three types of clamping components (clamping components 1-3), bundles, and Kevlar fibers were measured as the tested components. Furthermore, in optical cables constructed by winding the bundles and Kevlar fibers of the tested object around the outer periphery of the optical fiber unit, untwisting occurs in the multiple stranded optical fiber units. In contrast, in optical cables constructed by winding the clamping components (clamping components 1-3) of the tested object around the outer periphery of the optical fiber unit, untwisting of the optical fiber unit is suppressed. Clamping components 2 and 3 are water-absorbing clamping components, specifically water-absorbing yarn. Additionally, here, the applied load P is varied within the range of 0.0 to 2.5 N, such as... Figure 9B As shown, the circumference L2 was measured when a load P was applied to the winding component 53, and the compression ratio R was measured based on the initial circumference L1 and the circumference L2.

[0091] Figure 11 This is a graph showing the relationship between the applied load P and the compression ratio R. The horizontal axis of the graph shows the applied load P. Figure 9A as well as Figure 9BThe pulling load P (N) of the winding component 53. The vertical axis of the graph shows the compression ratio R of the component 19 being measured.

[0092] like Figure 11 As shown, in the case of bundled materials and Kevlar fibers, when the applied load P is 1.0 N or more, the compression ratio R hardly changes, and the amount of change in the compression ratio R is the degree of measurement error. In contrast, in the case of clamping components (clamping components 1 to 3), when the applied load P is 1.0 N or more, the compression ratio R increases as the applied load P increases. That is, it shows the case where the bundled materials and Kevlar fibers are components whose cross-sectional shape is difficult to change when lateral pressure is applied, while the clamping components are components whose cross-sectional shape changes more significantly when lateral pressure is applied compared to the bundled materials and Kevlar fibers. As long as the cross-sectional shape changes more significantly when lateral pressure is applied, the gaps inside the optical cable 1 can be continuously filled, thereby maintaining the posture of the components (e.g., fiber unit 11) inside the optical cable 1. Therefore, as Figure 11 As shown, the preferred clamping component increases the compression ratio R as the applied load P increases. In particular, the preferred clamping component increases the compression ratio R as the applied load P increases when it is 1.0 N or more. Furthermore, it is believed that the increase in compression ratio R as the applied load P increases when it exceeds 1.0 N also has an effect on suppressing the microbending loss of the optical fiber.

[0093] like Figure 10 as well as Figure 11 As shown, in the case of bundled materials and Kevlar fibers, the compression ratio R does not change when the applied load P is in the range of 1.5 to 2.0 N. This means that even with changes in lateral pressure, the cross-sectional shape of the bundled materials and Kevlar fibers does not change when the applied load P reaches 1.5 to 2.0 N. In other words, if the applied load P exceeds 1.5 N, the cross-sectional shape of the bundled materials and Kevlar fibers does not change. In contrast, in the case of clamping components (clamping components 1 to 3), when the applied load P is in the range of 1.5 to 2.0 N, the compression ratio increases as the applied load P increases. This means that, unlike bundled materials and Kevlar fibers, the cross-sectional shape of clamping components (clamping components 1 to 3) can change even when the applied load P exceeds 1.5 N. Thus, when comparing the clamping components (clamping components 1-3) with the bundle material and Kevlar fibers, a significant difference in the change of compression ratio R is observed when the applied load P is in the range of 1.5-2.0 N. It is believed that by utilizing this difference in the change of compression ratio R, the untwisting of the optical fiber unit in the optical cable constructed by winding the clamping components (clamping components 1-3) around the outer periphery of the optical fiber unit is suppressed. Therefore, it is preferable that the clamping material has the property that the compression ratio R increases as the applied load P increases, at least when the applied load P is in the range of 1.5-2.0 N.

[0094] Figure 10The right side shows the rate of change of compression ratio α (the ratio of the increase in compression ratio R to the increase in applied load P) for an applied load P in the range of 1.5 to 2.0 N. Components with a large value of the rate of change of compression ratio α have the characteristic that the compression ratio R increases more easily as the applied load P increases. Figure 10 The rate of change α of the compression ratio of each component shown is equivalent to Figure 11 The slope of the graph for an applied load P in the range of 1.5 to 2.0 N is equivalent to the connection... Figure 11 The slopes of the lines from two measurements were given for an applied load P ranging from 1.5 to 2.0 N. The rate of change α of the compression ratio of the clamped component was 0.17 to 0.26 (unit: N). -1 (In contrast, the rate of change of compression ratio of the bundle material and Kevlar fiber is approximately zero). Thus, it is preferable that the clamping member 17 wound around the outer periphery of the aforementioned optical fiber bundle 14 is a member whose rate of change of compression ratio α (the ratio of the increase in compression ratio R to the increase in the applied load P) is 0.17 or more within the range of 1.5 to 2.0 N.

[0095] like Figure 10 as well as Figure 11 As shown, the maximum compression ratio R of the bundled material is 0.40, and the maximum compression ratio R of the Kevlar fiber is 0.33. In contrast, the maximum compression ratio R of clamping components 1 to 3 are 0.91, 0.57, and 0.66, respectively, which are larger than those of the bundled material and Kevlar fiber. The reason is that in the case of the bundled material and Kevlar fiber, the compression ratio R hardly changes when a load P of 1.0 N or more is applied. In contrast, in the case of clamping components (clamping components 1 to 3), the compression ratio R changes when a load P of 1.0 N or more is applied, resulting in a larger change in the cross-sectional shape. From this point of view, it is also shown that the bundled material and Kevlar fiber are components whose cross-sectional shape is difficult to change when lateral pressure is applied, while the clamping components are components whose cross-sectional shape changes more significantly when lateral pressure is applied compared to the bundled material and Kevlar fiber. As described above, any component whose cross-sectional shape changes significantly when lateral pressure is applied can continuously fill the gaps inside the optical cable 1, thereby maintaining the orientation of components (e.g., fiber unit 11) within the internal space of the optical cable 1. Therefore, it is preferable that the clamping component can deform to a compression ratio R of 0.57 or higher.

[0096] It was confirmed that when the applied load on the winding member 53 was released after the compression ratio measurement (when the lateral pressure applied to the measured member 19 was removed), the cross-sectional shape of the clamping member (clamping member 1 to 3) changed significantly, roughly returning to the cross-sectional shape before the measurement. Thus, it is preferable that the clamping member 17 wound around the outer periphery of the aforementioned fiber bundle 14 has the property of easily restoring its cross-sectional shape when the lateral pressure is removed (high recovery rate).

[0097] Figure 12 This is a cross-sectional diagram illustrating the clamping component 17 inside the optical cable 1. Figure 12 yes Figure 1B This is an enlarged view of the periphery of a clamping component 17 of the optical cable 1 shown. The cross-section of the clamping component 17 in the figure is depicted with shading corresponding to density. Here, areas of high density in the clamping component 17 are given darker shading, and areas of low density are given lighter shading.

[0098] like Figure 12 As shown, in the cross-section of the clamping member 17, there are regions with different densities. In areas with wider gaps inside the optical cable 1, the density of the clamping member 17 is lower (lighter shaded), while in areas with narrower gaps inside the optical cable 1, the density of the clamping member 17 is higher (denseer shaded). Therefore, it is assumed that in areas of denser density, there is greater lateral pressure from the surroundings compared to areas of lighter density, resulting in greater compressive deformation. Thus, it is preferable that there are regions of different densities in a certain cross-section of the clamping member 17. That is, it is preferable that the density of the clamping member 17 is non-uniform in a certain cross-section. In other words, it is preferable that the clamping member 17 can deform into regions of different densities in a certain cross-section (preferably deformable so that the density varies depending on the region). By using such a clamping member 17, the gaps inside the optical cable 1 can be continuously filled as the internal space deforms, thereby maintaining the orientation of the components (e.g., fiber optic units 11) inside the optical cable 1.

[0099] ===Other Implementation Methods===

[0100] The above embodiments are provided to facilitate understanding of the present invention and are not intended to limit or explain the embodiments of the present invention. The present invention can be modified / improved without departing from its spirit, and the present invention naturally includes its equivalents. Furthermore, the above embodiments can be appropriately combined.

[0101] Explanation of reference numerals in the attached figures

[0102] 1… Optical cable, 10… Core, 11… Optical fiber unit, 12… Inner layer unit, 13… Outer layer unit, 14… Optical fiber bundle, 15… Optical fiber, 16… Bundle material, 17… Clamping component, 18… Pressing tape, 19… Component to be measured, 20… Outer sheath, 21… Tension member, 22… Tear rope, 40… Manufacturing system, 41… Optical fiber supply unit, 42… Bundling device, 43… Clamping supply unit, 43′… Clamping winding unit, 44… Panel, 441… Through hole, 45… Extrusion molding unit, 46… Cooling device, 47… Winding unit, 51… Weight, 52… Measuring device, 53… Winding component.

Claims

1. An optical cable, characterized in that, The optical cable has multiple optical fiber units, and each optical fiber unit has an optical fiber bundle composed of multiple optical fibers. Multiple optical fiber units are twisted together. At least one fiber bundle has a clamping component wound around its outer periphery. Let P be the load applied to the winding member that is wound around the outer periphery of the clamping member, where the unit of P is N. And when the load P is applied to the winding component and lateral pressure is added to the clamping component, the compression ratio of the clamping component is set as R. When the load P is between 1N and 2.5N, the compression ratio R increases as the load P increases.

2. The optical cable according to claim 1, characterized in that, The optical fiber unit has a bundle for binding the plurality of optical fibers.

3. The optical cable according to claim 2, characterized in that, The clamping component is wound around the outside of the bundle.

4. The optical cable according to any one of claims 1 to 3, characterized in that, The optical cable includes an optical fiber unit having the clamping component and an optical fiber unit without the clamping component.

5. The optical cable according to any one of claims 1 to 3, characterized in that, The inner layer unit is composed of the aforementioned optical fiber units. An outer layer unit is formed by arranging multiple optical fiber units circumferentially on the outside of the inner layer unit. The optical fiber unit constituting the inner layer unit has the clamping component.

6. The optical cable according to claim 5, characterized in that, The outer unit includes an optical fiber unit having the clamping component and an optical fiber unit without the clamping component.

7. The optical cable according to claim 6, characterized in that, An optical fiber unit without the clamping component is disposed between two optical fiber units having the clamping component in the outer unit.

8. The optical cable according to any one of claims 1 to 3, characterized in that, When the winding spacing of the clamping component is set to P1 and the twisting spacing of the plurality of optical fiber units is set to P2, P1 / P2 is greater than 0.

1.

9. The optical cable according to any one of claims 1 to 3, characterized in that, The clamping component is not engaged with other components, but is wound in an SZ shape around the outer periphery of the optical fiber bundle.

10. The optical cable according to any one of claims 1 to 3, characterized in that, When the load P is in the range of 1.5 to 2.0 N, the compression ratio R increases as the load P increases.

11. The optical cable according to any one of claims 1 to 3, characterized in that, When the increase in the compression ratio R is defined as the ratio of the increase in load P to the increase in load P when the load P is in the range of 1.5 to 2.0 N, and the unit of α is N, -1 , α is 0.17 or higher.

12. The optical cable according to any one of claims 1 to 3, characterized in that, Let P be the load applied to the winding member that is wound around the outer periphery of the clamping member, where the unit of P is N. And when the load P is applied to the winding component and lateral pressure is added to the clamping component, the compression ratio of the clamping component is set as R. The clamping component can be deformed to a compression ratio R of 0.57 or higher.

13. The optical cable according to any one of claims 1 to 3, characterized in that, Multiple optical fiber units are twisted together in an SZ shape.

14. A method for manufacturing an optical cable, comprising the following steps: Insert the fiber bundle into each of the multiple through holes in the panel. Inserting the clamping component into at least one of the through holes of the panel; and By oscillating the panel, the clamping component is wound around the outer periphery of at least one of the fiber bundles. Let P be the load applied to the winding member that is wound around the outer periphery of the clamping member, where the unit of P is N. And when the load P is applied to the winding component and lateral pressure is added to the clamping component, the compression ratio of the clamping component is set as R. When the load P is between 1N and 2.5N, the compression ratio R increases as the load P increases.

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