Method for manufacturing stranded wire

Abstract

To provide a method for manufacturing a stranded wire in which the shape of a hollow part is stabilized and the outer shape is formed into an elliptical shape or an oval shape.SOLUTION: The optical fiber cable is composed of two layers of a first preliminary outer layer 2a and a second preliminary outer layer 2a provided inside the first preliminary outer layer 2b, a hollow part 3 is formed inside the second preliminary outer layer, and the number of first preliminary element wires 4 constituting the first preliminary outer layer 2a is the same as the number of second preliminary element wires 5 constituting the second preliminary outer layer 2b. In the manufacturing method of the twisted wire 10, a preliminary twisted wire 1 in which the diameters of wire rods to be the bases of first preliminary wires are formed larger than the diameters of wire rods to be the bases of second preliminary wires is manufactured, and a part of the preliminary twisted wire 1 is pressurized and deformed by a die 11 which is divided into two from the outside and in which the shape of the 11c of an inner peripheral surface in a closed state is formed in an elliptic shape or an oval shape.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a stranded wire. [Background technology]

[0002] In the electric wire market, from the viewpoint of making electric wires and cables thinner, lighter, and more functional, a stranded conductor has been proposed in which a first outer layer is formed by circumferentially arranging first wires so that the cross section is closer to a circular shape, and a second outer layer is formed by circumferentially arranging second wires inside the first outer layer, with the inside of the second outer layer being hollow (Patent Document 1).

[0003] In recent years, attention has been focused on the fact that the cooling effect can be enhanced by circulating cool air or the like through the hollow part of this stranded conductor, and the use of the above stranded conductor as Litz wire for magnet coils in electric vehicles has been considered. When used in magnet coils, it is desirable for the outer shape of the stranded conductor to be elliptical or oval.

[0004] On the other hand, for a stranded conductor consisting of one layer having a hollow portion, it has been proposed to roll the stranded conductor to have an oval or oval outer shape (Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-158331 [Patent Document 2] Japanese Patent Application Publication No. 11-111063 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in a rolled state, the conductor tends to stretch in the longitudinal direction but has poor ductility in the transverse direction. Therefore, when attempting to deform the outer diameter of a two-layer stranded conductor by roll rolling, problems arise in that twisting occurs due to the twist pitch after rolling, the arrangement of the inner second outer layer becomes disordered, the wires cross each other, and the hollow portion collapses.

[0007] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a method for manufacturing a stranded wire in which the shape of the hollow portion is stable and the outer shape is elliptical or oval. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems, the present invention provides a method for producing a pre-stranded wire, which is composed of two layers, a first pre-stranded outer layer and a second pre-stranded outer layer provided inside the first pre-stranded outer layer, a hollow portion formed inside the second pre-stranded outer layer, the first pre-stranded outer layer being made of first pre-strands, the second pre-stranded outer layer being made of second pre-strands, the number of the first pre-strands and the number of the second pre-strands being the same, and the diameter of the wire material that is the base of the first pre-strands being larger than the diameter of the wire material that is the base of the second pre-strands, a die that is divided into two from the outside and has an inner peripheral surface that is elliptical or oval when closed, is closed and pressed, and then the die is opened; Then, a portion of the pre-twisted wire is moved a predetermined distance in the axial direction, and then the portion of the pre-twisted wire is repeatedly pressed while closing a two-part mold from the outside.

[0009] Furthermore, the circumferential length of a circle having a radius equal to the average distance from the axis of the pre-stranded wire to the outer edge of each of the first pre-stranded wires may be the same as the circumferential length in a cross section of the mold.

[0010] Furthermore, the outer surface of the first preliminary strand constituting the first preliminary outer layer of the preliminary stranded wire is not compressively deformed, The stranded wire may have a first outer layer and a second outer layer, and the outer surface of the first wire constituting the first outer layer may not be compressively deformed.

[0011] The number of the first wires and the number of the second wires may each be an even number of six or more. [Effects of the Invention]

[0012] According to the present invention, a pre-stranded wire is composed of two layers, a first outer layer and a second outer layer provided inside the first outer layer, and a hollow portion is formed inside the second outer layer. A part of the pre-stranded wire is press-formed using a mold whose inner surface shape when closed is elliptical or oval. The pre-stranded wire is then moved a predetermined distance in the axial direction, and the pre-stranded wire is then press-formed from the outside using a mold divided into multiple parts. This process is repeated, and it is possible to prevent the collapse of the hollow portion due to twisting of the twisted wire, and to stably produce a twisted wire. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 2 is a cross-sectional view of a pre-stranded wire used in Example 1 of the present invention. [Figure 2] FIG. 2 is a perspective view of an example of a closed state of a mold used in Example 1 of the present invention. [Figure 3] FIG. 3 is a perspective view of another example of a mold used in Example 1 of the present invention in a closed state. [Figure 4] 1 is a cross-sectional view of an example of a stranded wire according to a first embodiment of the present invention. [Figure 5] FIG. 3 is a cross-sectional view of another example of the stranded wire according to the first embodiment of the present invention. [Figure 6] FIG. 10 is a cross-sectional view showing an example of a stranded wire according to a third embodiment of the present invention. [Figure 7] FIG. 10 is a cross-sectional view showing another example of a stranded wire according to Example 3 of the present invention. [Figure 8] FIG. 10 is a cross-sectional view showing another example of a stranded wire according to Example 3 of the present invention. [Figure 9] FIG. 10 is a cross-sectional view showing another example of a stranded wire according to Example 3 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the accompanying drawings.

[0015] [Example 1] First, the preliminary stranded wire will be described.

[0016] As shown in Fig. 1, the pre-stranded wire 1 is composed of a pre-stranded outer layer 2 consisting of two layers: a first pre-stranded outer layer 2a and a second pre-stranded outer layer 2b disposed inside the first pre-stranded outer layer 2a, and a hollow space 3 is formed inside the second pre-stranded outer layer 2b. Fig. 1 is a cross-sectional view of the pre-stranded wire 1 according to Example 1 of the present invention, cut in a direction perpendicular to the axial direction, and the diagonal lines indicating the cross sections of the individual wires have been omitted to avoid cluttering the drawing.

[0017] 1, the first preliminary outer layer 2a is formed by arranging 20 first preliminary strands 4 on the same circumference, and the 20 wire rods that form the 20 first preliminary strands 4 that make up the first preliminary outer layer 2a have a circular cross section and are all made of the same diameter and material. Adjacent first preliminary strands 4, 4 in the circumferential direction around the center of the pre-stranded wire 1 are arranged so as to abut on each other over the entire axial direction or part of the axial direction.

[0018] 1, the second preliminary outer layer 2b is formed by arranging 20 second preliminary strands 5 on the same circumference, and the 20 wire rods that form the 20 second preliminary strands 5 that make up the second preliminary outer layer 2b have a circular cross section and are all made of the same diameter and material. Adjacent second preliminary strands 5, 5 in the circumferential direction around the center of the pre-stranded wire 1 are arranged so as to abut on each other over the entire axial direction or part of the axial direction.

[0019] The number of first preparatory strands 4 constituting the first preparatory outer layer 2a is set to be the same as the number of second preparatory strands 5 constituting the second preparatory outer layer 2b.

[0020] The diameter d1 of the wire material that forms the basis of the first preliminary strand 4 that forms the first preliminary outer layer 2a is set to be larger than the diameter d2 of the wire material that forms the basis of the second preliminary strand 5 that forms the second preliminary outer layer 2b.

[0021] In an inner valley portion 6 formed by the outer surfaces of the first spare wires 4 constituting the first spare outer layer 2a, a portion of the outer surface of the second spare wire 5 constituting the second spare outer layer 2b is arranged so as to abut against a portion of the outer surface of the first spare wire 4 over its entire axial direction or over a portion of its axial direction.

[0022] The wire material that forms the basis of the first spare wire 4 that forms the first spare outer layer 2a and the wire material that forms the basis of the second spare wire 5 that forms the second spare outer layer 2b can be copper wire such as bare copper wire, oxygen-free copper wire, linear crystal oxygen-free copper wire, single crystal high-purity oxygen-free copper wire, copper wire plated with tin, nickel, silver, etc., aluminum wire, various alloy wires, and wires with an insulating coating such as enameled wire, Litz wire, formalin wire, etc.

[0023] In the present Example 1, the spare strands 4 and 5 were used, in which the relationship d2=0.76×d1 was established.

[0024] The cross-sectional shape of the pre-stranded wire 1 is formed to be substantially circular, that is, the distance from the center of the pre-stranded wire 1 to the outermost edge of each of the first pre-stranded strands 4 constituting the first pre-outer layer 2a is substantially the same. The pre-stranded wire 1 can be formed to be substantially circular without compressing its outer shape, and the pre-stranded strands 4, 5 can be brought into contact with almost all of the adjacent pre-stranded strands 4, 5. The pre-stranded wire 1 can be formed to be substantially circular without compressing its outer shape.

[0025] Next, a method for manufacturing the stranded wire 10 will be described.

[0026] In manufacturing the stranded wire 10, a mold 11 divided into a plurality of molds 11a and 11b is used as shown in FIGS.

[0027] The molds 11a and 11b of this embodiment can be moved in the vertical direction in FIGS. 2 and 3 by a driving means (not shown), and can be moved relatively close to or farther apart from each other.

[0028] When the mold 11 is closed as shown in Fig. 2 and Fig. 3, the shape of its inner peripheral surface 11c is formed into an ellipse as shown in Fig. 2 or an oval shape as shown in Fig. 3. It is preferable that the perimeter (2 × π × L1) of a circle (two-dot chain line in Fig. 1) whose radius is the average of the distances L1 from the axis of the pre-stranded wire 1 to the outer edges of the first pre-strands 4 is the same as the perimeter of the ellipse or oval shape in the cross section of the mold.

[0029] The axial length of the mold 11 is preferably 5 to 20 times the twist pitch of the pre-stranded wire 1, and in this example it was set to 10 times.

[0030] With the mold 11 open, the mold 11 is positioned outside a portion of the pre-stranded wire 1, and then the molds 11a and 11b are closed while applying pressure to deform a section of a predetermined length in the axial direction of the pre-stranded wire 1 to form the twisted wire 10.

[0031] By this pressure application, the first preparatory strand 4 becomes the first strand 14, the first preparatory outer layer 2a becomes the first outer layer 12a, the second preparatory strand 5 becomes the second strand 15, and the second preparatory outer layer 2b becomes the second outer layer 12b. The first outer layer 12a and the second outer layer 12b form the outer layer 12, and the stranded wire 10 has an oval or oval outer shape.

[0032] Next, after opening the mold 11, the preliminary stranded wire 1 is moved a predetermined distance in the axial direction so that a portion of the stranded wire 10 and a portion of the preliminary stranded wire 1 are positioned inside the mold 11, and then the mold is closed while applying pressure to form the stranded wire 10, and the axial length of the formed stranded wire 10 is extended as needed.

[0033] This process is repeated to produce the stranded wire 10. The sum of the cross-sectional areas of the wires 14, 15 in the longitudinal cross section of the stranded wire 10 is set to be the same as the sum of the cross-sectional areas of the preparatory wires 4, 5 in the longitudinal cross section of the preparatory wire 1. More preferably, the cross-sectional area of ​​each of the wires 14, 15 is the same as that of the preparatory wires 4, 5. By setting it in this way, the preparatory wire 1 does not stretch in the axial direction when the stranded wire 10 is formed using the mold 11, so there is no need to accommodate the axial stretch of the stranded wire 10, and the stranded wire 10 can be produced stably.

[0034] As shown in FIG. 4, the outer surface of the first wire 14 may be formed using a mold 11 so as not to be compressed and deformed, or as shown in FIG. 5, the outer surface of the first wire 14 may be formed using molds 11a and 11b so as to be compressed and deformed. However, it is preferable to prevent the first wire 14 from being compressed and deformed as much as possible in order to improve the physical properties, flexibility, etc. of the twisted wire 10.

[0035] The first wires 14 constituting the first outer layer 12a of the stranded wire 10 are arranged in an elliptical shape, and circumferentially adjacent first wires 14, 14 may be in contact with or spaced apart from each other. Even if the first wires 14, 14 are spaced apart from each other, the shape of the stranded wire 10 is stable because it is twisted and the second wires 15 are located inside.

[0036] The second wires 15 constituting the second outer layer 12b of the twisted wire 10 are arranged in an elliptical shape without crossing or intersecting, and the second wires 15, 15 adjacent to each other in the circumferential direction are abutted along their entire axial direction or along part of their axial direction.

[0037] A single first wire 14 is positioned in an outer valley portion 16 formed by the outer surfaces of circumferentially adjacent second wires 15, 15, and in the outer valley portion 16, a portion of the outer surface of the first wire 14 is arranged to abut against a portion of the outer surface of the second wire 15 over its entire axial direction or over part of its axial direction.

[0038] A hollow portion 13 is formed inside the twelfth outer layer.

[0039] The shape of the inner peripheral surface of the die 11 is designed so that the circumferential length (2×π×L1) of a circle in the pre-stranded wire 1, whose radius is the average of the distances L1 from the center to the outer edge of each of the first pre-stranded strands 4, is the same as the circumferential length of the elliptical or oval shape in the cross section of the die. The design is also based on the outer diameter of the pre-stranded wire 1, the inner diameter of the hollow portion 3, the diameters of the pre-stranded strands 4 and 5, whether the hollow portion 13 of the stranded wire 10 can be formed when molded, its shape, whether the sum of the cross-sectional areas of the strands 14 and 15 in the longitudinal cross section of the stranded wire 10 is the same as the sum of the cross-sectional area of ​​the pre-stranded strands 4 and 5 in the longitudinal cross section of the pre-stranded wire 1, and so on.

[0040] The stranded wire 10 can improve cooling efficiency by circulating cool air or the like within the hollow portion 13, and by making the outer diameter elliptical or oval, it can be used as a Litz wire for magnet coils in electric vehicles. The stranded wire 10 can also be used as a stranded conductor for electric wires and cables, a catheter tube used in treatment, a guide wire for passing through blood vessels, a wire for operating an endoscope, and other medical wires.

[0041] When the twisted wire 10 is manufactured using the mold 11, the pre-twisted wire 1 has good ductility in the longitudinal and transverse directions, allowing for stable production of the twisted wire 10. Since no rotational force is applied, as occurs in the case of rolling, collapse of the hollow portion 13 due to twisting of the twisted wire 10 can be prevented, allowing for stable production of the twisted wire 10.

[0042] Even in a large-diameter wire having 20 first wires 14 as in the present Example 1, the second wires 15 constituting the second outer layer 12b are arranged in an elliptical shape without crossing or intersecting, and circumferentially adjacent second wires 15, 15 abut over the entire axial direction or over part of the axial direction, and one first wire 14 is located in an outer valley portion 16 formed by the outer surfaces of circumferentially adjacent second wires 15, 15, so that even though it has a hollow portion 13, the shape of the second outer layer 12b can be made robust and the shape of the twisted wire 10 can be stabilized.

[0043] Even when a hard material is used for the wires 14, 15 that make up the stranded wire 10, the presence of the hollow portion 13 allows the stranded wire 10 to have excellent flexibility.

[0044] The outer surface of the first preparatory strand 4 that constitutes the preparatory strand 1 is made of a material that does not undergo compressive deformation, and the perimeter (2 × π × L1) of the circumference of a circle in the preparatory strand 1 whose radius is the average of the distances L1 from the center to the outer edge of each of the first preparatory strands 4 is made the same as the perimeter of the elliptical or oval shape in the cross section of the mold.This makes it possible to form the outer surface of the first preparatory strand 4 that constitutes the preparatory strand 1 without compressive deformation, and to form the outer surface of the first strand 14 that constitutes the stranded wire 10 without compressive deformation, and to form the stranded wire 10 without compromising the physical properties, flexibility, etc. of the strands 14, 15 of the stranded wire 10.

[0045] [Example 2] As long as it is possible to form an arrangement similar to that of the pre-stranded wire 1 of Example 1, the pre-stranded wire 1 can be formed using wires having any diameter other than the wires having the diameter described in Example 1. Furthermore, the pre-stranded wire 1 may be compressed from the outside of the first preliminary outer layer 2a, which is the outermost layer, using a compression die or the like.

[0046] This compression causes the outer periphery of the first preliminary strand 4 constituting the first preliminary outer layer 2a to be compressed and deformed, making the outer shape of the pre-stranded wire 1 closer to a perfect circle. Compression using a compression die or the like may be performed when manufacturing the pre-stranded wire 1 or after manufacturing the pre-stranded wire 1. The compression ratio may be set arbitrarily.

[0047] The other structures are the same as those in the first embodiment, and therefore the explanation will be omitted.

[0048] In the second embodiment, the same effects as those in the first embodiment can be achieved.

[0049] [Example 3] In the above-mentioned Examples 1 and 2, the twisted wire 10 is composed of 20 first wires 14 and 20 second wires 15, but the number of first wires 14 and second wires 15 can be set to any number, but it is preferable to compose each of the first wires 14 and second wires 15 with an even number of six or more.

[0050] The first wires 14 and the second wires 15 are arranged with the same regularity as in the above-mentioned Examples 1 and 2, and the stranded wire is manufactured by the same manufacturing method. In this example, too, it is preferable to form the mold so that the circumferential length of the circle in the pre-stranded wire, whose radius is the average of the distances from the center to the outer edge of each first pre-stranded wire, is the same as the circumferential length of the elliptical or oval shape in the cross section of the mold.

[0051] For example, as shown in FIG. 6, in the case of a stranded wire 21 in which the first wires 14 and the second wires 15 are each composed of an even number of six wires, the stranded wire 21 can be constructed by using wire material that forms the base of each wire 14, 15 such that the relationship d2 = 0.385 × d1 holds.

[0052] Furthermore, as shown in FIG. 7, in the case of a stranded wire 22 in which the first wires 14 and the second wires 15 are each composed of an even number of eight wires, the stranded wire 22 can be constructed by using wire material that serves as the base for each of the wires 14, 15, such that the relationship d2 = 0.495 × d1 holds.

[0053] Furthermore, as shown in FIG. 8, in the case of a stranded wire 23 in which the first wires 14 and the second wires 15 are each composed of an even number of 10 wires, the stranded wire 23 can be constructed by using wire material that serves as the base for each of the wires 14, 15, such that the relationship d2 = 0.575 × d1 holds.

[0054] Furthermore, as shown in FIG. 9, in the case of a stranded wire 24 in which the first wires 14 and the second wires 15 are each composed of an even number of 12 wires, the stranded wire 24 can be constructed by using wire material that serves as the base for each of the wires 14, 15, such that the relationship d2 = 0.63 × d1 holds.

[0055] The other structures are the same as those in the first and second embodiments, and therefore the explanation will be omitted.

[0056] In this third embodiment, the same effects as those in the first and second embodiments can be achieved. [Explanation of symbols]

[0057] 1 spare stranded wire 2a First preliminary outer layer 2b Second spare outer layer 3 Hollow part 4. First spare wire 5 Second spare wire 10 strands 11 Mold

Claims

1. a pre-stranded wire is manufactured, which is composed of two layers, a first pre-strand and a second pre-strand provided inside the first pre-strand, a hollow portion is formed inside the second pre-strand, the first pre-strand is made of first pre-strands, the second pre-strand is made of second pre-strands, the number of the first pre-strands is the same as the number of the second pre-strands, and the diameter of the wire material that is the base of the first pre-strands is larger than the diameter of the wire material that is the base of the second pre-strands; a die that is divided into two from the outside and has an inner peripheral surface that is elliptical or oval when closed, is closed and pressed, and then the die is opened; Then, a portion of the pre-stranded wire is moved a predetermined distance in the axial direction, and then the portion of the pre-stranded wire is pressed while closing a two-part mold from the outside. This method for manufacturing a twisted wire is characterized by repeating this process.

2. 2. The method for manufacturing a stranded wire according to claim 1, wherein the circumferential length of a circle whose radius is the average of the distances from the axial center to the outer edges of the first preparatory strands in the preparatory strand is the same as the circumferential length in a cross section of the mold.

3. The outer surface of the first preliminary strand constituting the first preliminary outer layer of the preliminary stranded wire is not compressively deformed, 3. The method for manufacturing a stranded wire according to claim 1, wherein the stranded wire has a first outer layer and a second outer layer, and the outer surface of the first wire constituting the first outer layer is not compressively deformed.

4. 3. The method for manufacturing a stranded wire according to claim 1, wherein the number of the first preparatory strands and the number of the second preparatory strands are each an even number of six or more.

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