Manufacturing method of hanging wire

Abstract

To provide a manufacturing method of a hanging wire capable of increasing strength of the hanging wire while suppressing an increase in a diameter and a weight of the hanging wire.SOLUTION: In a manufacturing method of a hanging wire 2 for supporting a trolley wire 3 that supplies electric power to a railway vehicle 9, a plurality of wire drawing dies 51 to 53 having different inner diameters are used, a single-head wire drawing step is performed multiple times in which wires 71 to 73 through which any one of the plurality of wire drawing dies 51 to 53 passes are wound up around drums 61 to 63, and an inner diameter of the wire drawing dies 51 to 53 used in the single-head wire drawing step is gradually reduced every time the single-head wire drawing step is repeated.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a catenary wire for supporting a contact wire that supplies power to a railway vehicle. [Background technology]

[0002] Electric power is supplied to railway vehicles via a contact wire installed above the tracks. The contact wire is further supported by a suspension wire installed above the contact wire via a hanger serving as a suspender. The suspension wire is suspended from the beam of an overhead pole via insulators at multiple support points along its length. The applicant has proposed such a suspension wire (feeder suspension wire) as described in Patent Document 1. The suspension wire is suspended with a predetermined sag (the difference in height between the support point and the lowest point of the suspension wire) indicated by the symbol D in Figure 1(a) of Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-59247 Summary of the Invention [Problem to be solved by the invention]

[0004] For example, in places where there are height restrictions above the tracks, such as inside tunnels, the suspension wires must be installed with high tension to minimize sag. Therefore, the suspension wires installed in such places must be stronger than usual. One way to increase the strength of the suspension wires is to increase the diameter of the wires and the cross-sectional area of ​​the conductors. However, increasing the diameter of the suspension wires increases the weight of the wires themselves, which creates new problems, such as the need to increase the support strength of the support points.

[0005] Therefore, an object of the present invention is to provide a method for manufacturing a suspension wire that can increase the strength of the suspension wire while suppressing increases in diameter and weight of the suspension wire. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, the present invention provides a method for manufacturing a suspension wire for supporting a trolley wire that supplies power to a railway vehicle, which method uses a plurality of wire drawing dies with different inner diameters, and performs a single-head wire drawing process multiple times in which a wire that has passed through any one of the plurality of wire drawing dies is wound onto a drum, and each time the single-head wire drawing process is repeated, the inner diameter of one of the wire drawing die is gradually reduced. [Effects of the Invention]

[0007] According to the method for manufacturing a suspension wire of the present invention, it is possible to increase the strength of the suspension wire while suppressing increases in diameter and weight of the suspension wire. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic diagram showing an overhead line system using a suspension wire according to an embodiment of the present invention, together with a railroad track and a railway vehicle; [Figure 2] FIG. [Figure 3] FIG. 2 is a structural diagram showing the suspension wires and trolley wires in the hanger and its surrounding area. [Figure 4] 1(a) to 1(c) are explanatory views showing a specific example of a wire drawing process. [Figure 5] FIG. 10 is an explanatory diagram showing a wire drawing process according to a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Embodiment Mode] <Overhead line configuration> 1 is a schematic diagram showing an overhead line system 1 using a suspension wire 2 according to an embodiment of the present invention, together with a track 8 and a railway vehicle 9. The railway vehicle 9 comprises a bogie 91 having a plurality of wheels 911, a car body 92 including a passenger compartment 921, and a pantograph 93 disposed on the roof of the car body 92. The wheel 911 is driven to rotate by a motor that rotates using power supplied from the pantograph 93.

[0010] The overhead contact system 1 includes a suspension wire 2, a contact wire 3, and a plurality of hangers 4 that suspend the contact wire 3 from the suspension wire 2. The suspension wire 2 is suspended from a beam 11 of an overhead contact line mast via insulators 12 at a plurality of support points 20 along its length. The contact wire 3 is installed along the track 8 and suspended from the suspension wire 2 by the plurality of hangers 4. The pantograph 93 has a slider 931 that slides on the contact wire 3. The slider 931 contacts the contact wire 3 from below and slides on the contact wire 3 as the railway vehicle 9 travels.

[0011] 2 is a cross-sectional view of the suspension wire 2. The suspension wire 2 is a stranded wire made by twisting together a plurality of wires 21, and in this embodiment, the suspension wire 2 is made by twisting together 37 wires 21 each having a circular cross section. Each of the wires 21 is a hard copper wire made of a copper alloy containing copper as the main component. The wire diameter D of the wires 21 is 21 is equal to or less than 4.0 mm, for example, 3.7 mm.

[0012] Figure 3 is a structural diagram showing one hanger 4 and the surrounding suspension wire 2 and trolley wire 3. The hanger 4 is made of a metal rod, and a hook portion 41 at its upper part is bent into a loop shape. A resin protective cover 13 is attached to the suspension wire 2. The protective cover 13 has a cylindrical portion 131 on which the hook portion 41 of the hanger 4 is hooked, and a pair of flanges 132 to prevent the hook portion 41 from coming off. An ear 14 that grips the trolley wire 3 is attached to the lower end of the hanger 4.

[0013] As shown in Figure 1, the suspension wire 2 is curved so that its height from the track 8 is high at the support points 20 and its height from the track 8 is low between adjacent support points 20. The lengths of the multiple hangers 4 between the suspension wire 2 and the contact wire 3 are adjusted so that the contact wire 3 is parallel to the track. Distance D in Figure 1 indicates the slack of the suspension wire 2. Here, slack refers to the degree of slack in the suspension wire 2 due to the weight of the suspension wire 2 and the contact wire 3, and is expressed by the difference between the height of midpoint P of the line segment L connecting the two support points 20 and the height of the suspension wire 2 below midpoint P.

[0014] For example, in sections where the height from the track 80 is limited, such as inside a tunnel, it is necessary to increase the tension of the suspension wire 2 and reduce the slack of the suspension wire 2. For this reason, a high-strength suspension wire 2 is used for the suspension wire 2 installed in such sections. In this embodiment, a high-strength suspension wire 2 is obtained by the manufacturing method described below.

[0015] <Summary of the manufacturing method of the suspension wire> The manufacturing method of the suspension wire 2 according to this embodiment includes a wire-rod forming process, a wire-drawing process, and a stranding process. The wires obtained in the wire-rod forming process are twisted together to form the suspension wire 2. In the wire-rod forming process, a molten copper alloy is cast and hot-rolled to form the wire. In the wire-drawing process, a plurality of wire-drawing dies with different inner diameters are used, and a single-head wire-drawing process is performed multiple times to wind a wire rod that has passed through one of the plurality of wire-drawing dies onto a drum. Each time the single-head wire-drawing process is repeated, the inner diameter of the single drawing die used for the wire-drawing is gradually reduced to obtain the wire 21. The number of repetitions of the single-head wire-drawing process is the same as the number of wire-drawing dies used in the wire-drawing process. In the stranding process, a twisting machine twists together the plurality of wires 21 to form the suspension wire 2. Next, a specific example of the wire-drawing process will be described in detail with reference to FIG. 4.

[0016] <Wire drawing process> 4(a) to 4(c) are explanatory diagrams showing a specific example of the wire drawing process. In the wire drawing process, first to third wire drawing dies 51 to 53 with different inner diameters and first to third drums 61 to 63 are used to reduce the diameter of a wire rod 70 delivered from a wire rod delivery machine 7 to a predetermined wire diameter. The diameter of the wire rod 70 is, for example, 8.0 mm. In this embodiment, the diameter of the wire to be processed is successively reduced from the wire rod 70 to the wire rod 21 through the first to third single-head wire drawing processes.

[0017] 4(a) to 4(c) show cross sections of the first to third wiredrawing dies 51 to 53 at the blowout section. The die hole diameter D1 (inner diameter) of the die hole 510 in the first wiredrawing die 51 is smaller than the diameter of the wire rod 70, and the die hole diameter D2 of the die hole 520 in the second wiredrawing die 52 is smaller than the die hole diameter D1 of the first wiredrawing die 51. Furthermore, the die hole diameter D3 of the die hole 530 in the third wiredrawing die 53 is smaller than the die hole diameter D2 of the second wiredrawing die 52. The die hole diameter D3 of the third wiredrawing die 53 is equal to the wire diameter of the wire 21.

[0018] In the first single-head wire drawing process, as shown in Fig. 4(a), a rough wire rod 70 delivered from a rough wire rod delivery machine 7 is passed through a first wire drawing die 51 and wound around a first drum 61 as a first wire rod 71 having a smaller diameter than the rough wire rod 70. In the second single-head wire drawing process, as shown in Fig. 4(b), the first drum 61 is used as the delivery-side drum, and the first wire rod 71 delivered from the first drum 61 is passed through a second wire drawing die 52 and wound around a second drum 62 on the take-up side as a second wire rod 72 having a smaller diameter than the first wire rod 71.

[0019] In the third single-head wire drawing process, as shown in Fig. 4(c), the second drum 62 is used as the drum on the delivery side, the second wire rod 72 delivered from the second drum 62 is passed through the third wire drawing die 53, and the third wire rod 73, which has a smaller diameter than the second wire rod 72, is wound around the third drum 63 on the take-up side. The third wire rod 73 wound around the third drum 63 is sent to the wire twisting process as the wire 21 that constitutes the suspension wire 2.

[0020] In the first single-head wire drawing process, the entire length of the wire rod 70 is fed out from the wire rod feeder 7, and the entire length of the first wire rod 71 is wound around the first drum 61. In the second single-head wire drawing process, the entire length of the first wire rod 71 is fed out from the first drum 61, and the entire length of the second wire rod 72 is wound around the second drum 62. In addition, in the third single-head wire drawing process, the entire length of the second wire rod 72 is fed out from the second drum 62, and the wire 21 obtained by drawing the second wire rod 72 is wound around the third drum 63.

[0021] <Comparative Example> 5 is an explanatory diagram showing a wiredrawing process according to a comparative example. In this comparative example, first to third wiredrawing dies 51 to 53 similar to those described above are used, and the first to third wiredrawing dies 51 to 53 are arranged in series between the rough wire drawing payoff device 7 and the winding drum 64 so that the inner diameters of the dies become smaller in that order, and continuous wiredrawing is performed. That is, a first wire rod 710 that has passed through the first wiredrawing die 51 is introduced into a second wiredrawing die 52 without being bent, and a second wire rod 720 that has passed through the second wiredrawing die 52 is introduced into a third wiredrawing die 53 without being bent. Then, a third wire rod 730 that has passed through the third wiredrawing die 53 is wound around the winding drum 64. The diameter and weight per unit length of the third wire rod 730 according to the comparative example are equivalent to the diameter and weight per unit length of the third wire rod 73 according to the present embodiment that has been subjected to the first to third single-head wiredrawing processes.

[0022] Compared with the third wire rod 730 of the comparative example, which was obtained by continuously drawing the wire using the first to third wiredrawing dies 51 to 53 arranged in series so that the inner diameter successively decreases, the third wire rod 73 of the present embodiment, which was obtained by the first to third single-head wiredrawing steps described above, has a tensile strength that is 5% or more higher. The third wire rods 73 are twisted together as element wires 21 to form the suspension wire 2, thereby obtaining a high-strength suspension wire 2. The principle by which the tensile strength of the third wire rod 73 of the present embodiment is higher than that of the comparative example is not entirely clear, but it is thought to be related to the fact that each time the wire rod is reduced in diameter by one wiredrawing die, the wire rod is curved by winding it around a drum and then returned to a straight shape.

[0023] Furthermore, the tensile strength of the third wire rod 73 of the present embodiment, which has been subjected to the first to third single-head wire drawing processes, is 5% or more higher than the standard values ​​of tensile strength for each diameter listed in Appendix 1 of JIS C 3101:1994 (Hard-drawn copper wire for electrical use). Appendix 1 of JIS C 3101:1994 specifies the following tensile strength values: 440 MPa when the diameter is 2.0 mm, 437 MPa when the diameter is 2.3 mm, 434 MPa when the diameter is 2.6 mm, 431 MPa when the diameter is 2.9 mm, 427 MPa when the diameter is 3.2 mm, 424 MPa when the diameter is 3.5 mm, 422 MPa when the diameter is 3.7 mm, and 419 MPa when the diameter is 4.0 mm.

[0024] <Effects of the embodiment> As described above, according to this embodiment, it is possible to increase the strength of the suspension wire 2 while suppressing increases in the diameter and weight of the suspension wire 2.

[0025] (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 in the following description do not limit the components in the claims to the members and the like specifically shown in the embodiments.

[0026] [1] A method for manufacturing a suspension wire (2) for supporting a trolley wire (3) that supplies power to a railway vehicle (9), the method comprising the steps of: using a plurality of wire-drawing dies (51-53) having different inner diameters (D1, D2, D3); carrying out a single-head wire-drawing process multiple times in which a wire (71-73) that has passed through any one of the plurality of wire-drawing dies (51-53) is wound around a drum (61-63); and gradually reducing the inner diameter (D1, D2, D3) of one of the wire-drawing dies (51-53) each time the single-head wire-drawing process is repeated.

[0027] [2] The method for manufacturing a suspension wire according to the above [1], wherein the tensile strength of the wire rod obtained by performing the single-head wire drawing process for the number of the plurality of wire drawing dies (51 to 53) is 5% or more higher than the tensile strength of the wire rod (730) obtained by performing continuous wire drawing using the plurality of wire drawing dies (51 to 53) arranged in series so that the inner diameters (D1, D2, D3) become smaller successively.

[0028] [3] The method for manufacturing the suspension wire (2) described in [1] or [2] above, further comprising a twisting process of twisting together a plurality of wire rods (73) that have been subjected to the single-head wire drawing process for the number of wire drawing dies (51 to 53).

[0029] Although the embodiments of the present invention have been described above, the invention according to the claims is not limited to the above embodiments. 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. Furthermore, the present invention can be appropriately modified and implemented without departing from the spirit of the invention, and can be modified, for example, as follows.

[0030] In the above embodiment, a case has been described in which three wire drawing dies (first to third wire drawing dies 51 to 53) are used to process the wire rod 70 into the wire 21 through the first to third single-head wire drawing processes, but two or four or more wire drawing dies may be used to process the wire rod 70 into the wire 21 by performing the single-head wire drawing process two or four or more times. Furthermore, the number, wire diameter, and material of the wires 21 in the suspension wire 2 are not limited to those exemplified in the above embodiment, and can be adjusted as appropriate. [Explanation of symbols]

[0031] 2...Suspension wire 21...Element wire 3... Contact wire 51-53... First to third wire drawing dies 61 to 63: First to third drums 71 to 73: First to third wire rods 9...Railway vehicle D1, D2, D3...Die hole diameter

Claims

1. A method of manufacturing a suspension wire for supporting a contact wire that supplies power to a railway vehicle, comprising: a single-head wire drawing process is carried out a plurality of times using a plurality of wire drawing dies having different inner diameters, and the wire rod is passed through any one of the plurality of wire drawing dies and wound around a drum; Each time the single-head wire drawing process is repeated, the inner diameter of the one wire drawing die is gradually reduced. Method of manufacturing a suspension wire.

2. the tensile strength of the wire rod obtained by performing the single-head wire drawing process using the same number of wire drawing dies as the number of the plurality of wire drawing dies is 5% or more higher than the tensile strength of the wire rod obtained by performing continuous wire drawing using the plurality of wire drawing dies arranged in series so that the inner diameters of the dies become smaller successively; A method for manufacturing a suspension wire according to claim 1.

3. The method further includes a twisting step of twisting together a plurality of wire rods that have been subjected to the single-head wire drawing step for the number of wire drawing dies. A method for manufacturing a suspension wire according to claim 1 or 2.

Images