Drum-wound trolley wire

Abstract

To provide a drum-wound trolley wire in which a trolley wire incorporating an optical fiber of 1800 m or more is wound on a drum, the drum-wound trolley wire enabling total length measurement of the optical fiber with OTDR.SOLUTION: The present invention provides a drum-wound trolley wire 100 in which a trolley wire 1 is wound on a drum 50, wherein a diameter of a trunk 51 of the drum 50 is 970 mm or more, the trolley wire 1 including a trolley wire main body 10 composed of a conductor and an optical fiber 20 housed in an optical fiber accommodating hole 14 of the trolley wire main body 10, and the trolley wire main body 10 having a length of 1800 m or more, and the optical fiber 20 having a transmission loss of 0.5 dB / km or less across the entire length of the trolley wire main body 10.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a drum-wound trolley wire in which a trolley wire incorporating an optical fiber as a wear detection wire is wound around a drum. [Background technology]

[0002] Conventionally, a trolley wire with an optical fiber embedded therein as a wear detection wire has been known (see, for example, Patent Document 1). Generally, after being manufactured, the trolley wire is wound around a drum for storage, transportation, etc. until it is stretched.

[0003] The drum on which the contact wire is wound is limited in size in order to be mounted on a rolling stock. In other words, even when winding a long contact wire, the diameter of the drum collar or the width of the drum body cannot be increased. Therefore, when winding a long contact wire, such as 1,800 m or more, onto a drum, the diameter of the drum body must be significantly reduced. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-1494 Summary of the Invention [Problem to be solved by the invention]

[0005] However, as the diameter of the drum becomes smaller, the curvature of the wound contact wire increases, which increases the distortion of the optical fiber embedded in the contact wire. When the distortion of the optical fiber increases, it becomes difficult to measure the entire length of the contact wire using an OTDR (optical time domain reflectometer) during production, making it difficult to guarantee the quality of the optical fiber over the entire length.

[0006] Therefore, the object of the present invention is to provide a drum-wound trolley wire in which a trolley wire containing an optical fiber of 1,800 m or more is wound around a drum, and which allows the entire length of the optical fiber to be measured using an OTDR. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, the present invention provides a drum-wound trolley wire in which a trolley wire is wound around a drum, wherein the diameter of the drum body is 970 mm or more, the trolley wire comprises a trolley wire body made of a conductor and an optical fiber accommodated in an optical fiber accommodating hole of the trolley wire body, the length of the trolley wire body is 1800 m or more, and the transmission loss of the optical fiber is 0.5 dB / km or less over the entire length of the trolley wire body. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a drum-wound trolley wire in which a trolley wire containing an optical fiber of 1800 m or more is wound around a drum, and which allows the entire length of the optical fiber to be measured using an OTDR. [Brief explanation of the drawings]

[0009] [Figure 1] Fig. 1(a) is a radial cross-sectional view of a trolley wire according to an embodiment of the present invention, and Fig. 1(b) is an enlarged cross-sectional view of the periphery of an optical fiber receiving hole of the trolley wire. [Figure 2] FIG. 2 is a cross-sectional view that schematically shows a cross section of a drum-wound trolley wire in which the trolley wire is wound around a drum. [Figure 3] FIG. 3 is a graph showing the transmission characteristics of light propagating through the optical fibers of sample A and sample B, obtained by OTDR measurement. [Figure 4] 4(a) and 4(b) are top views schematically showing the configuration of a die box for accommodating an optical fiber in a trolley wire body and for drawing the trolley wire body. [Figure 5]5(a) and 5(b) are front views of the wire pressing guide. DETAILED DESCRIPTION OF THE INVENTION

[0010] [Embodiment] (Contact wire structure) 1(a) is a radial cross-sectional view of a trolley wire 1 according to an embodiment of the present invention. The trolley wire 1 has a trolley wire body 10 made of a conductor having an optical fiber accommodating hole 14 therein, and an optical fiber 20 as a wear detection wire accommodated in the optical fiber accommodating hole 14 of the trolley wire body 10.

[0011] The trolley wire body 10 of the trolley wire 1 is an irregularly shaped round trolley wire and has a small arc surface 11 at the top, a large arc surface 12 at the bottom, V-shaped ear grooves 13 between the small arc surfaces 11 and large arc surfaces 12 on both sides, and a linear optical fiber accommodating hole 14 provided along the longitudinal direction of the trolley wire body 10 at a predetermined distance from the bottom of the large arc surface 12. The shape of the trolley wire body 10 corresponds to a grooved hard-copper trolley wire specified in JISE2101 or IEC62917.

[0012] The trolley wire body 10 is mainly composed of a copper alloy, for example, a Cu-Sn-In alloy or a Cu-Sn alloy. The nominal cross-sectional area of ​​the trolley wire body 10 is 170 mm 2 Here, the nominal cross-sectional area means the calculated cross-sectional area when it is assumed that the optical fiber receiving hole 14 is not provided. For example, when the nominal cross-sectional area is 170 mm 2 This means that the calculated cross-sectional area is approximately 170 mm 2 if the optical fiber receiving hole 14 is not provided. 2 (For example, 166.6 mm 2 Above, 173.4mm 2 This indicates that the tolerance is ±2% or less.

[0013] The length of the trolley wire body 10 is 1800 m or more, for example, 1800 m or more and 1850 m or less. When an extra length of 15 m is secured and the maximum wire length is 1835 m, the maximum total length is 1850 m.

[0014] When power is supplied to an electric car, such as a railway vehicle like a Shinkansen traveling at high speed, via the trolley wire 1, the bottom of the large arc surface 12 of the trolley wire body 10 comes into contact with the electric car's current collector, such as a pantograph. As a result, the sliding of the current collector causes wear of the trolley wire body 10, starting from the bottom of the large arc surface 12. As wear progresses, the optical fiber 20 breaks before reaching the set wear limit position 16, and the wire breakage detection system is activated, detecting that the trolley wire body 10 has worn close to its limit.

[0015] The optical fiber accommodating hole 14 is provided at a position such that the position of its upper end coincides with the wear limit position 16 of the trolley wire body 10. In the trolley wire body 10, two optical fiber accommodating holes 14 are provided, one on each side of the center line 30 of the trolley wire body 10, and one optical fiber 20 is accommodated in each of the two optical fiber accommodating holes 14. By using two optical fibers 20, wear can be detected even when uneven wear occurs.

[0016] 1(b) is an enlarged cross-sectional view of the periphery of the optical fiber accommodating hole 14 of the trolley wire 1. A circle 15 represented by a dotted line in the optical fiber accommodating hole 14 in FIGS. 1(a) and 1(b) is the largest true circle included in the cross section of the optical fiber accommodating hole 14. The diameter D0 of the circle 15 is called the effective diameter of the optical fiber accommodating hole 14, and the area of ​​the circle 15 is called the effective cross-sectional area of ​​the optical fiber accommodating hole 14.

[0017] Fig. 2 is a cross-sectional view schematically showing a cross section of a drum-wound trolley wire 100 in which the trolley wire 1 is wound around a drum 50. The drum 50 has a cylindrical body 51 for winding the trolley wire 1 and disk-shaped flanges 52 provided on both sides of the body 51. Fig. 2 shows the cross section of the trolley wire 1 wound in multiple layers from the bottom up, and omits the cross sections of the third and subsequent layers.

[0018] The diameter D1 of the body 51 of the drum 50 is 970 mm or more. By making the diameter D1 of the body 51 of the drum 50 970 mm or more and inserting the optical fiber 20 into the optical fiber accommodating hole 14 of the trolley wire body 10 using a dice box 70 described later, the transmission loss of the optical fiber 20 can be made 0.5 dB / km or less over the entire length of the trolley wire body 10, and the entire length of the optical fiber 20 can be measured with an OTDR (optical time domain reflectometer).

[0019] Furthermore, the diameter D1 of the body 51 of the drum 50 is within a range that allows the trolley wire 1 to be wound around the body 51 over its entire length. For example, if the diameter D1 of the body 51 of the drum 50 is 980 mm or less, the trolley wire 1 having a trolley wire body 10 of 1,850 m or less can be wound around the body 51 over its entire length.

[0020] The inner width W of the body 51 of the drum 50 is approximately 670 mm, for example, not less than 660 mm and not more than 680 mm.

[0021] In the example shown in Fig. 2, the trolley wire 1 is wound horizontally around the drum 50. That is, the center line 30 of the trolley wire body 10 is wound so as to be inclined from a direction perpendicular to the surface of the barrel 51 of the drum 50, typically so as to be approximately parallel. By winding the trolley wire 1 horizontally around the drum 50, it is possible to suppress the occurrence of corrugation after the installation caused by the trolley wire 1 undulating. On the other hand, when the trolley wire 1 is wound horizontally around the drum 50, the distances from the barrel 51 of the center of the trolley wire body 10 and the center of the optical fiber accommodating hole 14 are different, so that the strain of the optical fiber 20 becomes larger and the transmission loss becomes larger than when the trolley wire 1 is wound vertically around the drum 50. Note that, of the two optical fibers 20, the optical fiber 20a closer to the barrel 51 is subjected to compressive strain, and the optical fiber 20b farther from the barrel 51 is subjected to tensile strain.

[0022] Table 1 below shows the results of OTDR measurements carried out on four types of drum-wound contact wires 100 (referred to as samples A to D).

[0023] [Table 1]

[0024] The contact wire bodies 10 of the samples A to D all have a length of 1835 m and a nominal cross-sectional area of ​​170 mm 2 (having a diameter of approximately 15.5 mm), and the effective diameter of the optical fiber receiving hole 14 is approximately 1.8 mm. The inner width W of the body 51 of the drum 50 of samples A to D is all 670 mm. In addition, for samples A to D, the contact wire 1 is wound horizontally around the drum 50 like the drum-wound contact wire 100 shown in Figure 2, and the OTDR measurement was performed on the optical fiber 20a closest to the body 51.

[0025] In Table 1, "optical fiber diameter" is the diameter of the optical fiber 20. "Optical fiber occupancy" is the occupancy rate of the optical fiber 20 in the optical fiber accommodating hole 14, and is the ratio of the radial cross-sectional area of ​​the optical fiber 20 to the effective cross-sectional area of ​​the optical fiber accommodating hole 14. "Drum body diameter" is the diameter D1 of the cylindrical body 51 of the drum 50.

[0026] "OTDR measurement" in Table 1 is the result of the OTDR measurement. The result of the OTDR measurement "pass" means that the transmission loss of the optical fiber 20 is 0.5 dB / km or less over the entire length of the trolley wire body 10, and OTDR measurement of the optical fiber 20 is possible over the entire length of the trolley wire body 10. Furthermore, "partially impossible" means that the transmission loss is so large that light does not reach the position corresponding to the tip of the trolley wire body 10, and OTDR measurement of the optical fiber 20 is not possible over the entire length of the trolley wire body 10, or that even if measurement is possible over the entire length, a value exceeding 0.5 dB / km was obtained.

[0027] 3 is a graph showing the transmission characteristics, obtained by OTDR measurement, of light propagating through the optical fiber 20 of sample A and sample B. As shown in Table 1, sample A and sample B differ in the diameter D1 of the body 51.

[0028] In the trolley wire body 10 of sample A, in which the trolley wire 1 is wound around a drum 50 having a diameter D1 of the body 51 of 940 mm, the distance from the tip on the winding start side to the boundary between the part wound in the first layer around the body 51 and the part wound in the second layer is approximately 133 m.

[0029] As shown in Fig. 3, the position 133 m from the tip of the winding start side of the trolley wire body 10 almost coincides with the position where the backscattered light intensity of the optical fiber 20 of sample A suddenly drops, that is, the position where the transmission loss suddenly increases. This is thought to be because the curvature of the part of the trolley wire body 10 wound in the first layer around the trunk 51 is the highest, and the distortion of the part of the optical fiber 20 housed in that part becomes particularly large.

[0030] Based on this result, the inventors considered that if the diameter D1 of the body 51 is equal to or greater than the outer diameter D2 of the portion wound in the first layer around the body 51 of the trolley wire body 10 of sample A, the curvature of the portion wound in the first layer around the body 51 of the trolley wire body 10 will be equivalent to the curvature of the portion wound in the second layer or later around the body 51 of the trolley wire body 10 of sample A, and it will be possible to measure the entire length of the optical fiber 20 using an OTDR.

[0031] Here, the diameter D2 of sample A is calculated as 971 mm from the diameter D1 of 940 mm and the diameter of the trolley wire body 10 of 15.5 mm. The diameter D1 (970 mm) of the body 51 of samples B, C, and D is set based on the diameter D2 of sample A. It is considered that the reason why OTDR measurement of the optical fiber 20 is possible over the entire length of the trolley wire body 10 in samples B, C, and D is because the condition that the diameter D1 of the body 51 is 970 mm or more is satisfied.

[0032] "Extension" in Table 1 is the evaluation result of the amount of the optical fiber 20a pulled into the trolley wire body 10 when the trolley wire 1 is extended. In samples A to D, the trolley wire 1 is wound horizontally around the drum 50, and the length of the optical fiber 20a closer to the drum 50 within the trolley wire 1 is shorter than the length of the trolley wire body 10. Therefore, when the trolley wire 1 is pulled out from the drum 50 and extended, part of the optical fiber 20a that was located on the trunk 51 side of the trolley wire body 10 when the trolley wire 1 was wound around the drum 50 is pulled into the inside of the trolley wire body 10.

[0033] In the evaluation result for "extension compatibility" in Table 1, "Acceptable" means that the amount of retraction of the optical fiber 20a is within the allowable range for terminal processing on the extension vehicle, and "Difficult" indicates that the amount of retraction of the optical fiber 20a is large, making terminal processing of the optical fiber 20a difficult.

[0034] The amount of retraction of the optical fiber 20a depends on the occupancy rate of the optical fiber accommodating hole 14 by the optical fiber 20. In sample D, the more difficult the terminal treatment, the greater the amount of retraction of the optical fiber 20a. Therefore, in order to perform terminal treatment of the optical fiber 20a in an appropriate state, it is preferable that the occupancy rate of the optical fiber accommodating hole 14 by the optical fiber 20 is greater than 25.0%.

[0035] When drawing the trolley wire body 10, lubricating oil is applied in advance to the surface of the trolley wire body 10 that comes into contact with the wire drawing die to prevent seizure. The lubricating oil is applied to the trolley wire body 10 by spraying the lubricating oil onto the surface of the trolley wire body 10 rather than immersing the trolley wire body 10 in stored lubricating oil in order to prevent the lubricating oil from entering the open optical fiber accommodating hole 14. However, even if the lubricating oil is applied to the surface of the trolley wire body 10 by spraying, it is not possible to completely prevent the lubricating oil from entering the optical fiber accommodating hole 14, and therefore lubricating oil remains inside the optical fiber accommodating hole 14 after drawing the trolley wire body 10.

[0036] When the drum-wound trolley wire 100 is stored for a long period of time as a disaster spare, the lubricating oil remaining inside the optical fiber accommodating hole 14 is likely to adhere to the optical fiber 20. If the lubricating oil adheres to the optical fiber 20, the optical fiber 20a is hardly drawn into the trolley wire body 10 when the trolley wire 1 is extended, which may cause a problem of increased distortion of the optical fiber 20a.

[0037] The adhesion of the lubricating oil remaining inside the optical fiber accommodating hole 14 to the optical fiber 20 can be suppressed by reducing the occupancy rate of the optical fiber accommodating hole 14 by the optical fiber 20. In samples A to D, it was confirmed that there was little lubricating oil residue on the optical fiber 20 and adhesion hardly occurred, so it is preferable that the occupancy rate of the optical fiber accommodating hole 14 by the optical fiber 20 be 37.3% or less.

[0038] 4(a) and (b) are top views schematically showing the configuration of the die boxes 60 and 70 that accommodate the optical fiber 20 in the trolley wire body 10 and draw the trolley wire body 10. Note that Figs. 4(a) and (b) show how one optical fiber 20 is inserted into the trolley wire body 10, and do not show how another optical fiber 20 is inserted into the trolley wire body 10.

[0039] The die box 60 shown in Figure 4(a) is a die box conventionally used for drawing trolley wire containing optical fiber, and is equipped with a wire drawing die 61 for drawing the trolley wire body 10, and wire holder guides 62a, 62b, and 62c for guiding the trolley wire body 10 toward the wire drawing die 61.

[0040] 5(a) is a front view of the wire pressure guide 62a. The wire pressure guide 62a has a die hole 620 for passing (guiding) the trolley wire body 10. The wire pressure guides 62b and 62c also have die holes 620 like the wire pressure guide 62a.

[0041] When the die box 60 is used, the optical fiber 20 drawn out from the optical fiber bobbin 81 and passed through the horizontal payoff roll 82 and the vertical payoff roll 83 joins the trolley wire body 10 at a position P1 just before the trolley wire body 10 passes through the wire holding guide 62a, which is the farthest from the wire drawing die 61 among the wire holding guides 62a, 62b, and 62c. The trolley wire body 10 is fed horizontally (in a direction in which the two optical fiber accommodating holes 14 are aligned vertically), and the two optical fibers 20 join the trolley wire body 10 from above and below, respectively.

[0042] At position P1, the optical fiber 20 is inserted into the open optical fiber accommodating hole 14 of the trolley wire body 10. Then, the trolley wire body 10 with the optical fiber 20 inserted therein passes through the die holes 620 of the wire pressing guides 62a, 62b, and 62c and is drawn by the wire drawing dies 61. By being drawn by the wire drawing dies 61, the optical fiber accommodating hole 14 of the trolley wire body 10 is closed, and the optical fiber 20 is accommodated inside the optical fiber accommodating hole 14.

[0043] The die box 70 shown in Fig. 4(b) is a die box developed by the present inventors to realize the drum-wound trolley wire 100 according to the embodiment of the present invention. The trolley wire bodies 10 of samples A to D were drawn using the die box 70. The die box 70 differs from the die box 60 in the structure of the wire pressure guide.

[0044] 5(b) is a front view of the wire pressure guide 72a. The wire pressure guide 72a has a die hole 720 for passing (guiding) the trolley wire body 10 and an optical fiber through-hole 721 for passing (guiding) the optical fiber 20 before it is inserted into the trolley wire body 10. The wire pressure guide 72b has a die hole 720 and an optical fiber through-hole 721 similar to the wire pressure guide 72a. On the other hand, the wire pressure guide 72c has a structure similar to the wire pressure guide 72a, and has a die hole 720 but does not have an optical fiber through-hole 721.

[0045] When using the die box 70, the optical fiber 20 is pulled out from the optical fiber bobbin 81 and passes through the horizontal payoff roll 82 and the vertical payoff roll 83, passes through the optical fiber through-hole 721 of the wire holding guides 72a and 72b, and then joins the trolley wire body 10 at position P2 just before the trolley wire body 10 passes through the wire holding guide 72c.

[0046] At position P2, the optical fiber 20 is inserted into the open optical fiber accommodating hole 14 of the trolley wire body 10. Then, the trolley wire body 10 with the optical fiber 20 inserted therein passes through the die hole 720 of the wire pressing guide 72c and is drawn by the wire drawing die 71. By being drawn by the wire drawing die 71, the optical fiber accommodating hole 14 of the trolley wire body 10 is closed, and the optical fiber 20 is accommodated inside the optical fiber accommodating hole 14.

[0047] When using the die box 70, the optical fiber 20 is passed through the optical fiber passage hole 721 of the wire holding guides 72a, 72b before being inserted into the optical fiber accommodating hole 14 of the trolley wire body 10. Therefore, compared to when using the die box 60, in which the optical fiber 20 is inserted into the optical fiber accommodating hole 14 of the trolley wire body 10 immediately after passing through the payoff vertical roll 83, the insertion angle of the optical fiber 20 into the trolley wire body 10 is smaller, thereby reducing the load (elongation) on the optical fiber 20.

[0048] Furthermore, when using the die box 60, there is a possibility that the optical fiber 20 may get caught in the gap between the die hole 620 of the wire holding guides 62a, 62b, 62c and the trolley wire body 10 caused by the vibration of the trolley wire body 10 during wire drawing, resulting in damage such as external injury or breakage. However, when using the die box 70, the optical fiber 20 does not pass through the die hole 720 of the wire holding guides 72a, 72b, so the incidence of damage such as breakage can be significantly reduced.

[0049] 4(a) and (b), when the dice box 70 is used, the distance from the wire drawing die 71 to position P2 where the optical fiber 20 is inserted into the open optical fiber accommodating hole 14 of the trolley wire body 10 is shorter than the distance from the wire drawing die 61 to position P1 when the dice box 60 is used. This makes it possible to reduce the amount of lubricating oil applied to the trolley wire body 10 that adheres to the optical fiber 20, thereby suppressing an increase in distortion of the optical fiber 20a caused by the adhesion of lubricating oil to the optical fiber 20 when the above-mentioned drum-wound trolley wire 100 is stored for a long period of time.

[0050] (Effects of the embodiment) According to the above-described embodiment of the present invention, by using the die box 70 to wind the trolley wire 1, in which the optical fiber 20 is inserted into the optical fiber receiving hole 14 of the trolley wire body 10, around the drum 50 having a body 51 with a diameter D1 of 970 mm or more, it is possible to provide a drum-wound trolley wire 100 in which the transmission loss of the optical fiber 20 is 0.5 dB / km or less over the entire length of the trolley wire body 10, even when the trolley wire 1 incorporating the optical fiber 20 and having a length of 1,800 m or more is wound around the drum. Moreover, according to the drum-wound trolley wire 100 according to the embodiment of the present invention, even when the trolley wire 1 is wound horizontally around the drum 50 or when the drum-wound trolley wire 100 is stored for a long period of time, the entire length of the optical fiber 20 can be measured using an OTDR.

[0051] (Summary of the embodiment) Next, the technical ideas grasped from the above-described embodiments will be described by using the reference numerals and the like in the embodiments. However, the reference numerals and the like in the following description do not limit the components in the claims to the members and the like specifically shown in the embodiments.

[0052] [1] A drum-wound trolley wire (100) in which a trolley wire (1) is wound around a drum (50), the diameter of the body (51) of the drum (50) is 970 mm or more, the trolley wire (1) comprises a trolley wire body (10) made of a conductor and an optical fiber (20) accommodated in an optical fiber accommodating hole (14) of the trolley wire body (10), the length of the trolley wire body (10) is 1800 m or more, and the transmission loss of the optical fiber (20) is 0.5 dB / km or less over the entire length of the trolley wire body (10).

[0053] [2] The drum-wound trolley wire (100) according to the above [1], wherein the diameter of the body (51) of the drum (50) is 980 mm or less.

[0054] [3] The drum-wound trolley wire (100) according to [1] above, wherein the length of the trolley wire (1) is 1850 m or less.

[0055] [4] The drum-wound trolley wire (100) according to any one of the above [1] to [3], wherein the radial cross-sectional area of ​​the optical fiber (20) is greater than 25.0% of the effective cross-sectional area of ​​the optical fiber receiving hole (14).

[0056] [5] The drum-wound trolley wire (100) according to any one of the above [1] to [3], wherein the radial cross-sectional area of ​​the optical fiber (20) is 37.3% or less of the effective cross-sectional area of ​​the optical fiber receiving hole (14).

[0057] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit and scope of the invention.

[0058] Furthermore, the above-described embodiments do not limit the scope of the invention as claimed, and it should be noted that not all of the combinations of features described in the embodiments are necessarily essential to the means for solving the problems of the invention. [Explanation of symbols]

[0059] 1 Contact wire 10 Contact wire body 14 Optical fiber receiving hole 20, 20a, 20b optical fiber 50 drums 51 Torso 100 Drum-wound contact wire

Claims

1. A drum-wound contact wire in which the contact wire is wound around a drum, The diameter of the drum body is 970 mm or more, The trolley wire includes a trolley wire body made of a conductor and an optical fiber accommodated in an optical fiber accommodating hole of the trolley wire body, The length of the trolley wire body is 1800 m or more, a transmission loss of the optical fiber is 0.5 dB / km or less over the entire length of the contact wire body; Drum-wound contact wire.

2. The diameter of the drum barrel is 980 mm or less.

2. The drum-wound contact wire according to claim 1.

3. The length of the contact wire is 1850 m or less.

2. The drum-wound contact wire according to claim 1.

4. a radial cross-sectional area of ​​the optical fiber is greater than 25.0% of an effective cross-sectional area of ​​the optical fiber receiving hole; The drum-wound trolley wire according to any one of claims 1 to 3.

5. a cross-sectional area of ​​the optical fiber in the radial direction is 37.3% or less of an effective cross-sectional area of ​​the optical fiber receiving hole; The drum-wound trolley wire according to any one of claims 1 to 3.

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