Cable branch connection structure and method for manufacturing cable branch connection portion

Abstract

To provide a branch connection structure of a cable that can ensure proper conduction performance, and a method for manufacturing a branch connection part of a cable.SOLUTION: A method for manufacturing a branch connection part of a cable includes: an assembly process (step S1) of assembling a sleeve including a polishing part to a trunk cable having an exposure part with the polishing part opposite to the exposure part; a rotation process (step S2) of rotating the sleeve around an axis in a constant direction, with the exposure part in contact with a polishing part including a plurality of polishing projections formed on an inner face of a cylindrical body in a spiral shape around an axis and capable of polishing a surface of the exposure part and a plurality of groove parts formed between the polishing projections in a spiral shape around the axis and having their ends opening along the axis; and a crimping process (step S3) of covering the exposure part, the sleeve, and one end of a branch line conductor with a crimp contact around the axis, and crimping the crimp contact together with the exposure part, the sleeve, and one end of the branch line conductor.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a cable branch connection structure and a method for manufacturing a cable branch connection portion. [Background technology]

[0002] Conventionally, as a branch connection structure for a cable, for example, Patent Document 1 describes a branch connection structure for a cable that includes a trunk cable having a trunk conductor made of aluminum, a branch cable having a branch conductor made of copper and one end connected to an exposed portion of the trunk conductor of the trunk cable, and an electrolytic corrosion prevention structure at the connection portion between the trunk conductor and the branch conductor that prevents electrolytic corrosion between them. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-004766 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the cable branch connection structure described in the above-mentioned Patent Document 1, for example, an oxide film may be formed on the exposed portion of the trunk conductor made of aluminum, which may reduce the electrical conductivity. In such cases, the cable branch connection structure needs to remove the oxide film to ensure proper electrical conductivity, but there is room for further improvement in terms of a configuration that can ensure proper electrical conductivity without deteriorating workability.

[0005] Therefore, the present invention has been made in consideration of the above, and aims to provide a cable branch connection structure and a method for manufacturing a cable branch connection portion that can ensure appropriate conductivity performance. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, a method for manufacturing a cable branch connection portion according to the present invention includes an assembling step of assembling a tubular member, which is made of copper or a copper alloy and covers the exposed portion around the axis, to a trunk cable including a trunk conductor made of aluminum or an aluminum alloy and extending along an axis, and an insulating covering member covering the trunk conductor, and the trunk conductor having an exposed portion exposed from the insulating covering member, with the abrasive portion formed on an inner surface of the tubular member, with the abrasive portion facing the exposed portion; and after assembling the tubular member to the exposed portion in the assembling step, The method includes a rotation process in which the tubular member is rotated in a fixed direction around the axis while the polishing portion is abutted against the exposed portion, the polishing portion including a plurality of polishing protrusions capable of polishing the surface of the exposed portion and a plurality of grooves formed spirally around the axis between each of the polishing protrusions and having ends opening along the axis; and a crimping process in which, while abutting one end of the branch line conductor of a branch line cable having a branch line conductor formed of copper or a copper alloy against the tubular member rotated by the rotation process, the exposed portion, the tubular member, and one end of the branch line conductor are covered around the axis with a crimping member and the crimping member is used to crimp the exposed portion, the tubular member, and one end of the branch line conductor together.

[0007] The branch connection structure for a cable according to the present invention comprises a trunk cable including a trunk conductor formed of aluminum or an aluminum alloy and extending along an axis, and an insulating covering member covering the trunk conductor, the trunk conductor having an exposed portion exposed from the insulating covering member; a cylindrical member including a tubular body formed of copper or a copper alloy and covering the exposed portion around the axis, and a polishing portion formed on the inner surface of the tubular body, the cylindrical body being fixed to the exposed portion with the polishing portion abutting against the exposed portion; and a branch conductor formed of copper or a copper alloy, the cylindrical member being fixed to the exposed portion. the polishing portion includes a plurality of polishing projections formed on the inner surface of the cylindrical body in a spiral shape around the axis and capable of polishing the surface of the exposed portion, and a plurality of grooves formed between the polishing projections in a spiral shape around the axis and having ends that open along the axis, and the plurality of grooves are The cylindrical body is rotated around the axis in a state before the cylindrical member is assembled to the exposed portion and crimped by the crimping member. The polishing projections are characterized in that the polishing projections are filled with metal powder that is generated when the surface of the exposed portion is polished.

[0008] The branch connection structure for a cable according to the present invention comprises a trunk cable including a trunk conductor made of aluminum or an aluminum alloy and extending along an axis, and an insulating covering member covering the trunk conductor, the trunk conductor having an exposed portion exposed from the insulating covering member; a cylindrical body made of copper or a copper alloy and covering the exposed portion around the axis, and a polishing portion formed on the inner surface of the cylindrical body, the cylindrical body being fixed to the exposed portion with the polishing portion abutting against the exposed portion. a branch line cable having a branch line conductor formed of copper or a copper alloy, one end of the branch line conductor connected to the tubular member fixed to the exposed portion; and a crimping member that covers the exposed portion, the tubular member, and one end of the branch line conductor around the axis and is crimped together with the exposed portion, the tubular member, and one end of the branch line conductor in a state where the one end of the branch line conductor is in contact with the tubular member fixed to the exposed portion, wherein the tubular member is formed to protrude from the outer surface of the tubular main body. In a state before being assembled to the exposed portion and crimped by the crimping member The cylindrical body includes a protrusion that allows the cylindrical body to be rotated around the axis. [Effects of the Invention]

[0009] The manufacturing method for a cable branch connection according to the present invention involves rotating the tubular member in a fixed direction around its axis while the polishing portion of the tubular member is in contact with the exposed portion. As the tubular member is rotated, the polishing protrusions of the tubular member polish the oxide coating on the exposed portion of the trunk conductor, and the metal powder generated by the polishing can be discharged to the outside through the multiple grooves. The cable branch connection structure crimps the tubular member, the exposed portion, and one end of the branch conductor, thereby properly connecting the trunk conductor and the branch conductor via the tubular member. As a result, the manufacturing method for a cable branch connection and the cable branch connection structure ensure proper electrical conductivity. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a front view showing a cable branch connection structure according to an embodiment. [Figure 2]FIG. 2 is a cross-sectional view showing a cable branch connection structure according to the embodiment. [Figure 3] FIG. 3 is a schematic diagram of a cross section taken along the arrow MM shown in FIG. [Figure 4] FIG. 4 is a perspective view showing an example of the configuration of the sleeve according to the embodiment. [Figure 5] FIG. 5 is an enlarged view showing an example of the configuration of the polishing protrusions and grooves according to the embodiment. [Figure 6] FIG. 6 is a diagram illustrating how the sleeve according to the embodiment is assembled to the exposed portion of the main conductor. [Figure 7] FIG. 7 is a diagram showing the sleeve assembled to the exposed portion of the main conductor according to the embodiment being rotated. [Figure 8] FIG. 8 is a flowchart showing a method for manufacturing a branched connection portion of a cable according to the embodiment. [Figure 9] FIG. 9 is an enlarged view showing an example of the configuration of the polishing protrusions and grooves according to a modified example of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Modes (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the following embodiments. Furthermore, the components described below include those that can be easily imagined by a person skilled in the art and those that are substantially the same. Furthermore, the configurations described below can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the configuration can be made within the scope of the gist of the present invention.

[0012] [Embodiment] A cable branch connection structure 1 according to an embodiment and a method for manufacturing a cable branch connection part G will be described with reference to the drawings. The cable branch connection structure 1 is applied to low-voltage wiring, also known as a branch cable, in condominiums, buildings, apartment buildings, factories, tunnels, etc., and includes a trunk cable 10, a sleeve 20 as a tubular member, a branch cable 30, a crimp terminal 40 as a crimp member, and a resin molded part 50, as shown in Figures 1, 2, and 3.

[0013] The trunk cable 10 is a cable having a relatively large allowable current, for example, a cable having a larger allowable current than the branch cables 30. The trunk cable 10 includes a trunk conductor 11 and an insulating covering member 12.

[0014] The main conductor 11 is a conductor made of aluminum or an aluminum alloy. The main conductor 11 is formed, for example, by twisting together a plurality of wires made of aluminum or an aluminum alloy. The cross-sectional area of ​​the main conductor 11 is larger than the cross-sectional area of ​​the branch conductors 31 described below. The main conductor 11 extends along the axis X1.

[0015] The insulating covering member 12 covers the trunk conductor 11 and is made of an insulating resin or the like. The insulating covering member 12 covers the outer periphery of the trunk conductor 11, thereby covering the trunk conductor 11 from one side to the other along the axis X1.

[0016] The trunk cable 10 has an exposed portion 11a in the trunk conductor 11 that is exposed from the insulating covering member 12. The exposed portion 11a is a portion of the trunk conductor 11 that is exposed by, for example, peeling off a part of the insulating covering member 12 covering the trunk conductor 11 around the axis X1. A branch cable 30 is electrically connected to this exposed portion 11a.

[0017] Next, a description will be given of the sleeve 20. The sleeve 20 includes a cylindrical main body 21, an abrasive portion 22, and a protruding portion 23, as shown in FIG.

[0018] The cylindrical body 21 is made of copper or a copper alloy and has a cylindrical shape, and is provided with a slit (notch) along the axis X1. The slit allows both ends of the cylindrical body 21 around the axis X1 to be separated from each other, and the cylindrical body 21 is formed in a C-shape when viewed from the axis X1. The cylindrical body 21 is fixed to the exposed portion 11a of the trunk conductor 11 and covers the exposed portion 11a around the axis X1.

[0019] The polishing portion 22 polishes the oxide film formed on the exposed portion 11a. The polishing portion 22 is formed on the inner surface 21a of the cylindrical main body 21, and includes a plurality of polishing protrusions 22a and a plurality of grooves 22b.

[0020] The polishing protrusions 22a are capable of polishing the surface of the exposed portion 11a and are formed in a spiral shape around the axis X1 on the inner surface 21a of the cylindrical main body 21. Each of the polishing protrusions 22a protrudes in a protruding direction from the inner surface 21a of the cylindrical main body 21, is formed linearly in a fixed direction, and is inclined (intersecting) with respect to the axis X1. As shown in FIG. 5 , the polishing protrusions 22a have a plurality of fine protrusions formed on the polishing surface in the protruding direction, and the polishing surface is formed, for example, in the shape of a grater. When the sleeve 20 is assembled to the exposed portion 11a and the polishing portion 22 of the sleeve 20 is abutted against the exposed portion 11a, the polishing protrusions 22a polish the surface of the exposed portion 11a and remove an oxide film formed on the surface of the exposed portion 11a.

[0021] The grooves 22b are formed spirally around the axis X1 and are provided between the polishing protrusions 22a. That is, the grooves 22b and the polishing protrusions 22a are provided alternately. Each of the grooves 22b is recessed on the inner surface 21a of the cylindrical body 21, and each is formed linearly in a fixed direction and inclined (intersecting) with respect to the axis X1. Both ends 24a of the grooves 22b are open along the axis X1. That is, both ends 24a of the grooves 22b are exposed to the outside along the axis X1. The grooves 22b temporarily store metal powder generated when the polishing protrusions 22a polish and remove the oxide coating on the surface of the exposed portion 11a when the sleeve 20 is rotated in a fixed direction around the axis X1. The metal powder stored in the grooves 22b is pushed out by the metal powder newly removed by the rotation of the sleeve 20 and is discharged to the outside from the ends 24a of the grooves 22b. The grooves 22b are filled with the final metal powder generated when the surface of the exposed portion 11a is polished by the polishing protrusions 22a.

[0022] The protrusions 23 are operated when rotating the cylindrical main body 21. The protrusions 23 are formed to protrude from the outer surface of the cylindrical main body 21, and in this example, are provided at two locations spaced apart at a fixed interval. Each protrusion 23 is formed linearly and extends along the axis X1, extending from one end of the cylindrical main body 21 to the other end at the axis X1. The worker hooks his or her finger on the protrusion 23 and rotates the cylindrical main body 21 in a fixed direction around the axis X1.

[0023] Next, a description will be given of the branch cable 30. The branch cable 30 is a cable with a relatively small allowable current, for example, a cable with a smaller allowable current than the trunk cable 10. The branch cable 30 includes a branch conductor 31 and an insulating coating member 32.

[0024] The branch line conductor 31 is a conductor made of copper or a copper alloy. The branch line conductor 31 is formed, for example, by twisting together a plurality of wires made of copper or a copper alloy. The branch line conductor 31 has a smaller cross-sectional area than the main line conductor 11.

[0025] The insulating covering member 32 covers the branch line conductor 31 and is made of insulating resin or the like. The insulating covering member 32 covers the outer periphery of the branch line conductor 31, thereby covering the branch line conductor 31 from one side to the other side along the axis X.

[0026] At one end of the branch cable 30, one end 31a of the branch conductor 31 is exposed from the insulating covering member 32. The one end 31a of the branch conductor 31 is, for example, a portion of the end of the branch conductor 31 that is exposed by peeling off a part of the insulating covering member 32 that covers the branch conductor 31. The one end 31a of the branch conductor 31 is electrically connected to the outer surface of the sleeve 20 that is fixed to the exposed portion 11a. As a result, the one end 31a of the branch conductor 31 is electrically connected to the exposed portion 11a of the trunk conductor 11 via the sleeve 20.

[0027] Next, the crimp terminal 40 will be described. The crimp terminal 40 is a C-shaped terminal made of copper or a copper alloy, and for example, a general-purpose product is used. Since a general-purpose product can be used for the crimp terminal 40, productivity and procurement can be improved. The crimp terminal 40 is formed in a cylindrical shape, and a slit (notch) is formed along the axis X1, and the slit is formed so that both ends around the axis X1 can be separated. In other words, the crimp terminal 40 is formed in a C-shape when viewed from the axis X1.

[0028] With one end 31a of the branch line conductor 31 abutting against the sleeve 20 fixed to the exposed portion 11a, the crimp terminal 40 has the exposed portion 11a, the sleeve 20, and the one end 31a of the branch line conductor 31 inserted inward from the slit side to cover the periphery of the axis X1, and is compressed or crimped (also simply referred to as crimped) together with the exposed portion 11a, the sleeve 20, and the one end 31a of the branch line conductor 31. With the exposed portion 11a, the sleeve 20, and the one end 31a of the branch line conductor 31 crimped to the crimp terminal 40, the tip of the one end 31a of the branch line conductor 31 protrudes from one side of the axis X1 of the crimp terminal 40.

[0029] Next, the resin molded portion 50 will be described. The resin molded portion 50 is a portion in which exposed metal portions are covered with resin. The resin molded portion 50 covers, for example, the exposed portion 11a of the main conductor 11, the sleeve 20, and one end 31a of the branch conductor 31 with resin. In other words, the exposed portion 11a of the main conductor 11, the sleeve 20, and one end 31a of the branch conductor 31 are not exposed to the outside when covered by the resin molded portion 50. This prevents moisture from penetrating into the resin molded portion 50 from the outside, thereby suppressing galvanic corrosion that occurs between dissimilar metals such as aluminum and copper.

[0030] Next, a method for manufacturing the cable branch connection G will be described. The method for manufacturing the cable branch connection G may be performed manually by an operator using various devices, equipment, jigs, etc., or may be performed automatically using various manufacturing devices. The method for manufacturing the cable branch connection G includes an assembly process (step S1), a rotation process (step S2), a crimping process (step S3), and a sealing process (step S4). In the following description, the method for manufacturing the cable branch connection G will be described as being performed manually by an operator.

[0031] In the assembling process, a worker assembles the sleeve 20 to the trunk cable 10 having the exposed portion 11a with the polished portion 22 of the sleeve 20 facing the exposed portion 11a (step S1). At this time, as shown in Fig. 6, the worker inserts the sleeve 20 into the exposed portion 11a of the trunk conductor 11 from the slit side, and assembles the sleeve 20 to the exposed portion 11a (step S1).

[0032] Next, the worker moves to the rotation step. After assembling the sleeve 20 to the exposed portion 11a in the assembling step, as shown in FIG. 7, the worker rotates the sleeve 20 multiple times (e.g., three or more rotations) in a fixed direction around the axis X1 with the polishing portion 22 of the sleeve 20 in contact with the exposed portion 11a (step S2). At this time, the worker hooks his / her fingers on the protrusions 23 provided on the outer surface of the sleeve 20 and rotates the sleeve 20 in a fixed direction around the axis X1. By rotating the sleeve 20 three or more rotations in a fixed direction, the worker polishes and removes the oxide film formed on the exposed portion 11a with the polishing protrusions 22a of the sleeve 20, and discharges metal powder generated during the removal to the outside through the multiple grooves 22b. When the worker rotates sleeve 20 three or more times in a certain direction, after removing the oxide film formed on exposed portion 11a, the worker also polishes the aluminum base of exposed portion 11a, so that the metal powder made of the polished aluminum pushes out the metal powder made of the oxide film and discharges the metal powder made of the oxide film to the outside from ends 24a of multiple grooves 22b. In this way, the worker can fill multiple grooves 22b with metal powder (aluminum powder) generated when polishing the aluminum base of exposed portion 11a, and can remove the metal powder made of the oxide film from multiple grooves 22b.

[0033] Next, the worker moves to the crimping step, and with one end 31a of the branch conductor 31 of the branch cable 30 abutting against the outer surface of the sleeve 20 rotated in the rotating step, the worker covers the exposed portion 11a, the sleeve 20, and the one end 31a of the branch conductor 31 around the axis X1 with the crimp terminal 40, and crimps the crimp terminal 40 together with the exposed portion 11a, the sleeve 20, and the one end 31a of the branch conductor 31 (step S3). Here, after the oxide coating is removed from the exposed portion 11a of the trunk conductor 11 in the rotating step, an oxide coating may momentarily form again. In this case, when the worker crimps the exposed portion 11a with the crimp terminal 40, the polished protrusion 22a of the sleeve 20 can break through the oxide coating that momentarily formed on the exposed portion 11a. At this time, the worker can increase the contact area between the sleeve 20 and the exposed portion 11a by making the polished protrusions 22a of the sleeve 20 bite into the exposed portion 11a, thereby improving the electrical conductivity.

[0034] Next, the worker moves on to the sealing process, and uses a resin injection molding device (not shown) that injects resin to mold (seal) the exposed portion 11a of the main conductor 11, the sleeve 20, and one end 31a of the branch conductor 31 to form a resin molded portion 50 (step S4), thereby completing the manufacture of the branch connection portion G of the cable.

[0035] As described above, the manufacturing method of the cable branch connection portion G according to the embodiment includes at least an assembling step (step S1), a rotating step (step S2), and a crimping step (step S3). In the assembling step (step S1), a trunk cable 10 is assembled to the trunk cable 10, which includes a trunk conductor 11 made of aluminum or an aluminum alloy and extending along an axis X1, an insulating coating member 12 covering the trunk conductor 11, and an exposed portion 11a of the trunk conductor 11 exposed from the insulating coating member 12. The sleeve 20 is assembled to the trunk cable 10, which includes a tubular body 21 made of copper or a copper alloy and covering the exposed portion 11a around the axis X1, and a polished portion 22 formed on the inner surface 21a of the tubular body 21, with the polished portion 22 facing the exposed portion 11a. In the rotation process (step S2), after assembling the sleeve 20 to the exposed portion 11a in the assembly process (step S1), the sleeve 20 is rotated in a fixed direction around the axis X1 while the polishing portion 22, which includes a plurality of polishing protrusions 22a formed spirally around the axis X1 on the inner surface 21a of the cylindrical body 21 and capable of polishing the surface of the exposed portion 11a, and a plurality of grooves 22b formed spirally around the axis X1 between each polishing protrusion 22a and whose ends 24a open along the axis X1, is abutted against the exposed portion 11a. In the crimping process (step S3), one end 31a of the branch line conductor 31 of the branch line cable 30, which has the branch line conductor 31 formed of copper or a copper alloy, is abutted against the sleeve 20 rotated in the rotation process (step S2), and the crimp terminal 40 covers the exposed portion 11a, the sleeve 20, and the one end 31a of the branch line conductor 31 around the axis X1, and the crimp terminal 40 is crimped together with the exposed portion 11a, the sleeve 20, and the one end 31a of the branch line conductor 31.

[0036] With this configuration, when the sleeve 20 is rotated in the rotation step (step S2), the manufacturing method for the cable branch connection portion G can polish and remove the oxide coating on the exposed portion 11a of the trunk conductor 11 with the polishing protrusions 22a of the sleeve 20. Furthermore, the manufacturing method for the cable branch connection portion G can discharge metal powder generated when the polishing protrusions 22a of the sleeve 20 polish and remove the oxide coating on the exposed portion 11a of the trunk conductor 11 with the polishing protrusions 22a of the sleeve 20 to the outside through the multiple grooves 22b. As a result, the manufacturing method for the cable branch connection portion G can properly establish electrical continuity between the exposed portion 11a of the trunk conductor 11 and the one end 31a of the branch conductor 31 via the sleeve 20, thereby ensuring proper electrical continuity. The manufacturing method for a cable branch connection according to the comparative example may remove the oxide coating by applying a compound (abrasive particles) to the exposed portion 11a. However, in such cases, when the crimp terminal 40 is used for crimping, the compound may leak between the crimp terminal 40 and the exposed portion 11a. In this case, the compound must be wiped off, resulting in poor workability. Furthermore, the manufacturing method for a cable branch connection according to the comparative example involves applying the compound to the exposed portion 11a, which can result in uneven application and in variations in quality depending on the worker. In contrast, the manufacturing method for a cable branch connection G according to the embodiment removes the oxide coating without using a compound. This prevents the compound from leaking between the crimp terminal 40 and the exposed portion 11a, as in the comparative example, thereby suppressing deterioration in workability and variations in quality depending on the worker. As a result, the manufacturing method for a cable branch connection G according to the embodiment can manufacture a cable branch connection G that ensures appropriate conductivity without compromising workability.

[0037] In the manufacturing method of the cable branch connection portion G, in the rotation step (step S2), when the sleeve 20 is rotated, metal powder generated when the polishing protrusions 22a polish the oxide film of the trunk conductor 11 is discharged to the outside through the grooves 22b. With this configuration, the manufacturing method of the cable branch connection portion G can properly establish electrical continuity between the exposed portion 11a of the trunk conductor 11 and one end 31a of the branch conductor 31 via the sleeve 20, thereby ensuring proper electrical continuity.

[0038] In the manufacturing method of the cable branch connection part G, in the rotation step (step S2), the cylindrical body 21 is rotated in a fixed direction around the axis X1 by the protrusion 23 formed to protrude from the outer surface of the cylindrical body 21. With this configuration, the manufacturing method of the cable branch connection part G allows a worker to rotate the cylindrical body 21 by hooking his / her fingers on the protrusion 23, thereby preventing the worker's fingers from slipping when the cylindrical body 21 is rotated, and as a result, the workload can be reduced.

[0039] The cable branch connection structure 1 includes a trunk cable 10, a sleeve 20, a branch cable 30, and a crimp terminal 40. The grooves 22b of the sleeve 20 are filled with metal powder generated when the surface of the exposed portion 11a is polished with the polishing protrusions 22a. With this configuration, the cable branch connection structure 1 achieves the same effects as the manufacturing method of the cable branch connection portion G described above.

[0040] In the above-described cable branching connection structure 1, the sleeve 20 includes a protrusion 23 that protrudes from the outer surface of the cylindrical body 21 and allows the cylindrical body 21 to be rotated about the axis X1. With this configuration, the cable branching connection structure 1 can improve the rotational operability of the cylindrical body 21.

[0041] The cable branching connection structure 1 includes a trunk cable 10, a sleeve 20, a branching cable 30, and a crimp terminal 40, and the sleeve 20 includes a protruding portion 23 formed to protrude from the outer surface of a cylindrical body 21 and capable of rotating the cylindrical body 21 about an axis X1. With this configuration, the cable branching connection structure 1 can improve the rotational operability of the cylindrical body 21.

[0042] [Modification] Next, a modified example of the embodiment will be described. In the modified example, the same components as those in the embodiment will be denoted by the same reference numerals, and detailed description thereof will be omitted.

[0043] In the above description, the polishing protrusions 22a of the polishing portion 22 of the sleeve 20 are described as having a plurality of fine protrusions formed on the polishing surface in the protruding direction, but this is not limited to this. For example, as shown in Fig. 9, the polishing protrusions 23a of the polishing portion 22A of the sleeve 20A have three protrusions formed on the polishing surface in the protruding direction, and the polishing surface is formed, for example, in a pincushion shape. In this example, the polishing protrusions 23a include a first protrusion in the center, a second protrusion on one side, and a third protrusion on the other side, each extending along the axis X1, with the first protrusion in the center being higher than the second and third protrusions on both sides.

[0044] Although the sleeve 20 has been described as including the protrusion 23, the present invention is not limited to this and the sleeve 20 may not include the protrusion 23.

[0045] In the rotating step (step S2), an example has been described in which the cylindrical main body 21 is rotated by the protrusion 23, but the present invention is not limited to this, and the rotation does not necessarily have to be performed by the protrusion 23. [Explanation of symbols]

[0046] 1 Cable branch connection structure 10 Trunk Cable 11 Main conductor 11a Exposed part 12 Insulating coating material 20 Sleeve (cylindrical member) 21 Cylindrical body 21a Inside 22, 22A Polishing section 22a, 23a Polishing protrusion 24a end 22b, 23b Multiple grooves 23 Protrusion 30 Branch cable 31 Branch line conductor 31a One end of branch line conductor 40 Crimp terminal (crimping member) X1 axis

Claims

1. an assembling process for assembling a tubular member, which includes a tubular main body made of copper or a copper alloy and covering the exposed portion around the axis, and a polishing portion formed on an inner surface of the tubular main body, to a trunk cable that includes a trunk conductor made of aluminum or an aluminum alloy and extending along an axis, and an insulating covering member that covers the trunk conductor, and has an exposed portion of the trunk conductor exposed from the insulating covering member, with the polishing portion facing the exposed portion; a rotating step of rotating the cylindrical member in a fixed direction around the axis while the polishing portion, which includes a plurality of polishing protrusions formed spirally around the axis on the inner surface of the cylindrical main body and capable of polishing the surface of the exposed portion, and a plurality of grooves formed spirally around the axis between each of the polishing protrusions and having ends that open along the axis, is in contact with the exposed portion after the assembling step of assembling the cylindrical member to the exposed portion; a crimping step of covering the exposed portion, the tubular member, and the one end of the branch line conductor of a branch line cable, the branch line conductor being formed of copper or a copper alloy, around the axis with a crimping member, and crimping the crimping member together with the exposed portion, the tubular member, and the one end of the branch line conductor, while abutting the one end of the branch line conductor on the tubular member rotated in the rotating step; A method for manufacturing a branched connection portion of a cable, comprising:

2. 2. A method for manufacturing a cable branch connection portion as described in claim 1, wherein, in the rotating process, when the tubular member is rotated, metal powder generated when the polishing protrusion portion polishes the oxide coating of the trunk conductor is discharged to the outside through the groove portion.

3. 3. The method for manufacturing a cable branch connection portion according to claim 1 or 2, wherein in the rotating process, the tubular body is rotated in a fixed direction around the axis by a protrusion formed protruding from the outer surface of the tubular body.

4. a trunk cable including a trunk conductor formed of aluminum or an aluminum alloy and extending along an axis, and an insulating covering member covering the trunk conductor, the trunk conductor having an exposed portion exposed from the insulating covering member; a cylindrical member including a cylindrical main body formed of copper or a copper alloy and covering the exposed portion around the axis, and a polishing portion formed on an inner surface of the cylindrical main body, wherein the cylindrical main body is fixed to the exposed portion with the polishing portion in contact with the exposed portion; a branch line cable having a branch line conductor made of copper or a copper alloy, one end of the branch line conductor being connected to the tubular member fixed to the exposed portion; a crimping member that covers the exposed portion, the tubular member, and the one end of the branch line conductor around the axis in a state where one end of the branch line conductor is in contact with the tubular member fixed to the exposed portion, and is crimped together with the exposed portion, the tubular member, and the one end of the branch line conductor, the polishing portion includes a plurality of polishing protrusions formed spirally around the axis on the inner surface of the cylindrical body and capable of polishing the surface of the exposed portion, and a plurality of grooves formed spirally around the axis between the polishing protrusions and having ends that open along the axis, A cable branch connection structure characterized in that the multiple grooves are filled with metal powder produced when the tubular body is rotated around the axis and the surface of the exposed portion is polished by the polishing protrusion portion before the tubular member is assembled to the exposed portion and crimped by the crimping member.

5. The cable branching connection structure described in claim 4, wherein the tubular member includes a protrusion formed to protrude from the outer surface of the tubular main body and capable of rotating the tubular main body around the axis before being assembled to the exposed portion and crimped by the crimping member.

6. a trunk cable including a trunk conductor formed of aluminum or an aluminum alloy and extending along an axis, and an insulating covering member covering the trunk conductor, the trunk conductor having an exposed portion exposed from the insulating covering member; a cylindrical member including a cylindrical main body formed of copper or a copper alloy and covering the exposed portion around the axis, and a polishing portion formed on an inner surface of the cylindrical main body, wherein the cylindrical main body is fixed to the exposed portion with the polishing portion in contact with the exposed portion; a branch line cable having a branch line conductor made of copper or a copper alloy, one end of the branch line conductor being connected to the tubular member fixed to the exposed portion; a crimping member that covers the exposed portion, the tubular member, and the one end of the branch line conductor around the axis in a state in which the one end of the branch line conductor is in contact with the tubular member fixed to the exposed portion, and is crimped together with the exposed portion, the tubular member, and the one end of the branch line conductor, A cable branching connection structure characterized in that the tubular member includes a protrusion formed to protrude from the outer surface of the tubular main body and capable of rotating the tubular main body around the axis before being assembled to the exposed portion and crimped by the crimping member.

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