CONNECTION MEMBER

Technical Field

The present disclosure relates to a cable connection method, a cable connection structure, and a cable connection member.

Background

Patent Document 1 describes a method of forming a connection portion of a plastic insulated power cable with an impervious layer. In this forming method, when a connection portion of a plastic insulated power cable is formed that includes, below a plastic sheath, an impervious layer formed of a metal laminated tape including a metal tape on which a plastic layer is laminated, an end portion of the plastic sheath closely contacted by the impervious layer is cut into strips. The cut portion is folded back to expose a metal tape surface, and a metal grounding conductor is solder-connected to the metal tape surface and electrically connected to a metal shielding layer of a cable.

Patent Document 2 describes a ground structure of a power cable with an impervious layer. The ground structure is a ground structure for a power cable including an impervious layer formed of a cable impervious layer formed of a metal laminate lying between a cable sheath and a cable shielding layer.

The ground structure includes a grounding terminal connected to a grounding conductor and a fastener electrically and mechanically connecting the grounding terminal and the cable impervious layer. The fastener includes a single-end screw including a first fastener and a second fastener. The first fastener inserted into a through hole from the cable impervious layer side with the grounding terminal inserted in between, the through hole penetrating the cable sheath and the cable impervious layer in the radial direction, is threadably engaged with the second fastener inserted into the through hole from the cable sheath side and clamped to the first fastener to fix the grounding terminal to the cable impervious layer.

Citation List Patent Literature

Patent Document 1 JP 62-147905 A Patent Document 2: JP 2019-122103 A

Summary

Technical Problem

In a case where the plastic sheath is cut into strips and the cut portion is folded back to expose the metal tape surface, to which the metal grounding conductor is solder-connected, as described above, then the solder-connected portion may fail to have high strength. In other words, the strength of the solder connection may decrease due to thermal expansion and contraction. Additionally, the reliability of the solder joint depends on the proficiency of an operator performing solder connection, and the like, there is room for improvement in terms of reliability of the connection. The ground structure described above includes the grounding terminal connected to the grounding conductor, the first fastener inserted into the through hole from the cable impervious layer side, and the second fastener inserted into the through hole from the cable sheath side and clamped to the first fastener. In the ground structure, the through hole is formed in the cable sheath and the cable impervious layer, the first fastener and the second fastener are inserted into the through hole, and the second fastener is clamped to the first fastener. Since the through hole is formed in the cable sheath and the cable impervious layer in advance as described above, there is room for improvement in the workability of installation of the cable connection structure.

Solution to Problem

A cable connection method according to the present disclosure is a cable connection method for a cable including an impervious layer located on an inner side of a cable sheath and a shielding layer located on an inner side of the impervious layer, the cable connection method including the steps of exposing the shielding layer by stripping the cable sheath and the impervious layer off from the shielding layer to space the cable sheath and the impervious layer apart from the shielding layer, piercing, with a piercing terminal attached to a grounding conductor, a portion of the cable sheath and the impervious layer which portion is spaced apart from shielding layer to fix the piercing terminal to the portion of the cable sheath and the impervious layer which portion is spaced apart from shielding layer, and connecting the grounding conductor extending from the piercing terminal, to the shielding layer, in a state of the grounding conductor being bent.

In the cable connection method, the cable sheath and the impervious layer are stripped off to expose the shielding layer located on the inner side of the cable sheath and the impervious layer, and the portion of the cable sheath and the impervious layer which portion is spaced apart from the shielding layer is pierced with the piercing terminal attached with the grounding conductor. Accordingly, the grounding conductor extending from the piercing terminal is brought into contact with the shielding layer to fix the grounding conductor to the shielding layer, thus allowing the impervious layer to be electrically and mechanically connected to the shielding layer. By electrically connecting the shielding layer to the impervious layer, the potential of the impervious layer can be made equal to the potential of the shielding layer, suppressing induction of voltage. Thus, discharge caused by induction of voltage can be suppressed. In addition, by using the piercing terminal and the grounding conductor to connect the impervious layer and the shielding layer, the need for solder connection can be eliminated, thus allowing the reliability of the connection to be improved. The grounding conductor attached with the piercing terminal can be connected to the shielding layer by piercing with the piercing terminal, thus enabling a reduction in the number of components and allowing facilitation of an operation for installing a cable connection structure. Furthermore, the grounding conductor is connected to the shielding layer in a state of being bent, and thus even in a case where thermal expansion or the like occurs, the bent portion can be caused to follow thermal expansion or the like. Thus, even in a case where thermal expansion or the like occurs, the connection between the impervious layer and the shielding layer can be more reliably maintained, thus allowing the reliability of the connection to be further improved.

The grounding conductor may have a flat shape.

The grounding conductor may have a net shape.

The cable connection method described above may include the step of wrapping a grounding spring around the grounding conductor extending from the bent portion along the shielding layer.

The grounding conductor may have a length of 100 mm or more and 200 mm or less.

The grounding conductor may have a cross-sectional area of 1.25 mm ² or more and 14 mm ² or less.

In the step of fixing the piercing terminal, a plurality of the piercing terminals may be fixed.

The piercing terminal may include a blade portion piercing the portion of the cable sheath and the impervious layer which portion is spaced apart from the shielding layer, and a number of the blade portions may be 2 or more and 10 or less.

A cable connection structure according to the present disclosure is a cable connection structure provided in a cable including an impervious layer located on an inner side of a cable sheath and a shielding layer located on an inner side of the impervious layer, the cable connection structure including a grounding conductor and a piercing terminal attached to the grounding conductor and piercing a portion of the cable sheath and the impervious layer which portion is spaced apart from the shielding layer, wherein the grounding conductor is connected in a bent state to the shielding layer.

The cable connection structure is provided in the cable including the cable sheath, the impervious layer, and the shielding layer, and the cable sheath and the impervious layer include a portion spaced apart from the shielding layer. The piercing terminal attached with the grounding conductor pierces the spaced-apart portion of the cable sheath and the impervious layer. The grounding conductor extending from the piercing terminal is connected in a bent state to the shielding layer. Accordingly, the grounding conductor extending from the bending portion is brought into contact with the shielding layer to fix the grounding conductor to the shielding layer, thus allowing the impervious layer to be electrically and mechanically connected to the shielding layer. Thus, the potential of the impervious layer can be made equal to the potential of the shielding layer to suppress induction of voltage, restraining discharge caused by the induction of voltage. As is the case with the cable connection method described above, the piercing terminal and the grounding conductor are used to connect the impervious layer and the shielding layer, thus eliminating the need for solder connection. This allows the reliability of the connection to be improved. The grounding conductor can be connected to the shielding layer by piercing the cable sheath and the grounding conductor with the piercing terminal, thus enabling a reduction in the number of components and allowing facilitation of the operation for installing the cable connection structure. The grounding conductor is connected to the shielding layer in a state of being bent, and thus even in a case where thermal expansion or the like occurs, the bent portion can be caused to follow thermal expansion or the like. Consequently, even in a case where thermal expansion or the like occurs, the connection between the impervious layer and the shielding layer can be more reliably maintained, thus allowing the reliability of the connection to be further improved.

A cable connection structure according to another aspect of the present disclosure includes a shielding layer grounding conductor pulled out from the shielding layer, the shielding layer grounding conductor includes a first ground lead-out portion connected to the shielding layer and a second ground lead-out portion extending from the first ground lead-out portion in a longitudinal direction of the cable to a position where the second ground lead-out portion is connected to a terminal, the first ground lead-out portion is located on an inner side of an impervious layer built-in tube covering the cable, and the second ground lead-out portion is located on an outer side of the impervious layer built-in tube, and the cable connection structure includes a grounding conductor lead-out protection portion covering the second ground lead-out portion.

In the cable connection structure, the shielding layer grounding conductor includes the first ground lead-out portion connected to the shielding layer and the second ground lead-out portion extending from the first ground lead-out portion in the longitudinal direction of the cable to the position where the second ground lead-out portion is connected to the terminal. The first ground lead-out portion is provided on the inner side of the impervious layer built-in tube. Accordingly, formation of recesses and protrusions on the first ground lead-out portion can be suppressed, thus allowing suppression of wrinkling of the impervious layer of the impervious layer built-in tube. Additionally, the second ground lead-out portion located on the outer side of the impervious layer built-in tube is covered with the grounding conductor lead-out protection portion, thus allowing protection of the second ground lead-out portion located on the outer side of the impervious layer built-in tube.

A cable connection member according to the present disclosure is a cable connection member attached to a cable including an impervious layer located on an inner side of a cable sheath and a shielding layer located on an inner side of the impervious layer, the cable connection member including a grounding conductor having a flat shape and a net shape, a piercing terminal attached to the grounding conductor and piercing a portion of the cable sheath and the impervious layer which portion is spaced apart from the shielding layer, and a grounding spring wrapped around the grounding conductor extending along the shielding layer.

In the cable connection member, the piercing terminal attached with the grounding conductor pierces the portion of the cable sheath and the impervious layer which portion is spaced apart from the shielding layer. The grounding conductor extending from the piercing terminal is disposed to extend along the shielding layer. Thus, when the grounding conductor extending from the piercing terminal piercing the cable sheath and the impervious layer is brought into contact with the shielding layer to fix the grounding conductor to the shielding layer, the impervious layer can be electrically and mechanically connected to the shielding layer. Consequently, the potential of the impervious layer can be made equal to the potential of the shielding layer, suppressing induction of voltage and discharge. In addition, the need for solder connection can be eliminated to improve the reliability of the connection, and the grounding conductor can be connected to the shielding layer by piercing the cable sheath and the grounding conductors with the piercing terminal, thus, allowing facilitation of the operation for installing the cable connection structure. In the cable connection member, the grounding conductor can be fixed by wrapping a grounding spring around the grounding conductor contacting the shielding layer. Consequently, the reliability of the connection can be further improved without using solder. Additionally, the grounding conductor extending from the piercing terminal can be disposed in a state of being bent along the inner side of the cable sheath and the impervious layer and along the shielding layer, and thus even in a case where thermal expansion occurs, the bending portion can be caused to follow thermal expansion or the like. Thus, even in a case where thermal expansion or the like occurs, the connection between the impervious layer and the shielding layer can be more reliably maintained, thus allowing the reliability of the connection to be further improved.

Advantageous Effects of Invention

According to the present disclosure, the reliability of the connection can be enhanced, and the operation for installing the cable connection structure is facilitated.

Brief Description of the Drawings

FIG. 1 is a cross sectional view illustrating a cable connection structure according to an embodiment.

FIG. 2(a) is a diagram schematically illustrating an inner cold shrink tube according to an embodiment.

FIG. 2(b) is a cross sectional view illustrating an example of an inner cold shrink tube according to an embodiment.

FIG. 3(a) is a diagram schematically illustrating an outer cold shrink tube according to an embodiment.

FIG. 3(b) is a cross sectional view illustrating an example of an outer cold shrink tube according to an embodiment.

FIG. 4 is a diagram illustrating an insulating tube of a cable connection member according to an embodiment.

FIG. 5 is a diagram illustrating a connector of the cable connection member according to an embodiment.

FIGS. 6(a) and 6(b) are diagrams illustrating a cable connection structure according to an embodiment.

FIG. 7 is a cross-sectional view of a cable as an example.

FIG. 8 is a diagram illustrating a piercing terminal and a grounding conductor of the cable connection member according to an embodiment.

FIG. 9(a) is a diagram illustrating a piercing terminal of the cable connection member according to an embodiment. FIG. 9(b) is a diagram illustrating a grounding conductor of the cable connection member according to an embodiment. FIG. 9(c) is a diagram illustrating a grounding spring of the cable connection member according to an embodiment.

FIGS. 10(a), 10(b), and 10(c) are diagrams illustrating a procedure of a method for connecting a cable according to an embodiment.

FIGS. 11(a) and 11(b) are diagrams illustrating the procedure of the method for connecting a cable according to an embodiment.

FIGS. 12(a) and 12(b) are diagrams illustrating the procedure of the method for connecting a cable according to an embodiment.

FIG. 13 is a diagram illustrating the procedure of the method for connecting a cable according to an embodiment.

FIG. 14 is a diagram illustrating the procedure of the method for connecting a cable according to an embodiment.

FIGS. 15(a) and 15(b) are diagrams illustrating the procedure of the method for connecting a cable according to an embodiment.

FIG. 16(a) and 16(b) are diagrams illustrating a cable connection structure according to a modified example.

FIG. 17 is a diagram illustrating a cable connection structure according to a modified example.

FIG. 18 is a diagram schematically illustrating a shielding layer grounding conductor in the cable connection structure.

FIG. 19 is a cross-sectional view illustrating an example of a first ground lead-out portion and a second ground lead-out portion of the shielding layer grounding conductor in the cable connection structure.

FIG. 20 is a side view schematically illustrating the first ground lead-out portion.

FIG. 21 is a side view schematically illustrating the first ground lead-out portion and the second ground lead-out portion.

FIG. 22 is a side view schematically illustrating a grounding conductor lead-out protection portion covering the second ground lead-out portion.

FIG. 23 is a cross-sectional view illustrating a grounding conductor lead-out protection portion according to a modified example.

FIG. 24 is a cross-sectional view illustrating a grounding conductor lead-out protection portion according to a modified example.

FIG. 25 is a perspective view schematically illustrating a metal member of the second ground lead-out portion in FIG. 24.

Detailed Description

Now, with reference to the drawings, a cable connection method, a cable connection structure, and a cable connection member according to the present disclosure will be described. In the description of the drawings, the same or corresponding elements are denoted by the same reference signs, and redundant description will be appropriately omitted. In addition, the drawings may be simplified or exaggerated in part for ease of understanding, and the dimensional ratios, etc. are not limited to those illustrated in the drawings.

First, the term “cable” used herein includes a power cable such as a CVT cable, an insulated wire, and a communication cable, and encompasses a wide variety of cables. “Cable Connection Portion” includes a connection portion that connects a plurality of cables each other, and the periphery of the connection portion, a connection portion that connects each of the cables and a connector, and the periphery of the connection portion, and a connection portion that connects the cable and equipment other than the connector, and the periphery of the connection portion. The term “inner side” as used herein refers to a cable conductor side of a member covering the cable, that is, the inner side of the cable in the radial direction. “Outer side” refers to a cable conductor opposite side (cable sheath side) of the member covering the cable, that is, the outer side of the cable in the radial direction.

In an embodiment, the cable includes a cable sheath, an impervious layer, and a shielding layer. “Cable sheath” refers to an outer skin (outer covering) of the cable. “Impervious layer” refers to a layer that blocks water including moisture. “Shielding Layer” is a metal layer grounded formed of, e g., copper. The cable sheath and the impervious layer are pierced with a piercing terminal attached to a grounding conductor. “Grounding conductor” is wiring connected to ground. “Piercing terminal” refers to a terminal including a portion that pierces the cable sheath, and including, for example, a claw portion that pierces the cable sheath.

As illustrated in FIG. 1, the cable connection structure 1 according to the present embodiment, as an example, includes a pair of cables 2, a cable connection portion 10 connecting a pair of cables 2 together, a pair of inner cold shrink tube (Pre-Stretched Tube, Inner Cold Shrink PST Tube) 20 covering the cable 2, and a pair of outer cold shrink tube (Pre-Stretched Tube, Outer Cold Shrink PST Tube) 30 covering the cable connection portion 10 and the inner cold shrink tube 20.

The cable 2 is, for example, a power cable of rated 66 kV. However, the cable 2 may be a power cable of 66 kV or more (as an example, 77 kV or 154 kV). The cable 2 includes, for example, an impervious layer 2h (see FIG. 7) including a conductor 2b, an insulating layer 2c covering the conductor 2b, a semi-conductive layer 2d covering the insulating layer 2c, a shielding layer 2f covering the semi- conductive layer 2d, and an impervious layer 2h laminated with a semi -conductive layer 2g covering the shielding layer 2f (see FIG. 7), and a cable sheath 2j covering the impervious layer 2h. For example, the shielding layer 2f is a shielding copper tape. As an example, the cable connection portion 10 includes a shielding treated portion 16 at both ends in a longitudinal direction D1 of an insulating tube 11 described below. The shielding treated portion 16 will be described below in detail.

The conductor 2b has a cross-sectional area of, for example, 80 (mm ² ) or more and 600 (mm ² ) or less, and the cable connection portion 10 has an outer diameter (diameter) of 90 (mm) or more. The cable connection portion 10 has, for example, a larger outer diameter than the cable 2. The outer diameter of the cable connection portion 10 may have a lower limit of 100 (mm), 110 (mm), 120 (mm), or 130 (mm). The outer diameter of the cable connection portion 10 may have an upper limit of 200 (mm), 170 (mm), or 150 (mm). For example, the outer diameter of the cable connection portion 10 is 135 (mm) or more and 145 (mm) or less. However, the outer diameter of the cable connection portion 10 is not limited to the values described above, and is not particularly limited.

For example, the cable connection portion 10 is provided at an end portion of the cable 2, and the end portions of the pair of cables 2 are connected to each other. As an example, one of the cables 2, the cable connection portion 10, and the other cable 2 are disposed in alignment along the longitudinal direction D1 of the cable connection structure 1. The cable connection member 100 as an example includes the inner cold shrink tube 20 covering a portion of the cable connection portion 100 located adjacent to the cable connection portion 10, the outer cold shrink tube 30 covering the cable connection portion 10 and the inner cold shrink tube 20, a piercing terminal 40 fixed to the cable 2 turned up (see FIGS. 6(a) and 6(b)), a grounding conductor 50 extending from the piercing terminal 40, and a grounding spring 60 wrapped around the grounding conductor 50 and the shielding layer 2f.

FIG. 2(a) is a perspective view schematically illustrating the inner cold shrink tube 20 as an example. FIG. 2 (b) is a schematic cross-sectional view of the inner cold shrink tube 20. As illustrated in FIGS. 2(a) and 2(b), the inner cold shrink tube 20 may be expanded in diameter by an expanded diameter holding member 23. The expanded diameter holding member 23 includes a disassembly line 23b formed in a direction in which the axis LI of the expanded diameter holding member 23 extends (hereinafter, also referred to as an axial direction). The expanded diameter holding member 23 is, for example, a cylindrical, tubular hollow member. The disassembly line 23b is formed such that the line advances gradually in the axial direction while revolving or revolving and reversing around the axis LI of the expanded diameter holding member 23.

As a material of the diameter holding member 23, a resin material such as polyethylene or polypropylene is used as an example. The expanded diameter holding member 23 can be pulled out along the disassembly line 23b as a core ribbon 23c that has a string-like body. The portion where the disassembly line 23b is formed is thinner than the remaining surrounding portion, and is easily ruptured.

For example, the disassembly line is not limited to an aspect in which the disassembly line is spirally formed like the disassembly line 23b, and may be formed in an SZ shape, or may have any shape as long as the expanded diameter holding member 23 can be pulled out. Pulling the core ribbon 23c sequentially ruptures the expanded diameter holding member 23 along the disassembly line 23b, and is continuously pulled out as a new core ribbon 23c. The disassembly line 23b is formed, for example, with a constant pitch, and thus, the width of the core ribbon 23c pulled out is constant. However, the width of the core ribbon 23c need not be constant.

The disassembly line 23b may be formed only on an inner circumferential surface of the expanded diameter holding member 23, or may be formed only on an outer circumferential surface of the expanded diameter holding member 23, or may be formed on both the inner circumferential surface and the outer circumferential surface of the expanded diameter holding member 23. The expanded diameter holding member 23 with the disassembly line 23b may be manufactured, for example, by spirally turning the disassembly line 23b, while fixing adjacent portions of the disassembly line 23b each other by bonding, welding, engagement, or a combination thereof, or may be manufactured by directly forming the disassembly line 23b in a cylindrical member.

The tubular, hollow expanded diameter holding member that can be pulled out may be in an aspect in which the core ribbon is pulled to sequentially shrink the inner cold shrink tube as is the case with the expanded diameter holding member 23 described above, or in an aspect in which the expanded diameter holding member slides relative to the inner cold shrink tube and is pulled out from the inner cold shrink tube. The expanded diameter holding member 23 includes a first end portion 23d corresponding to a start point side for pulling out the expanded diameter holding member 23 as the core ribbon 23c, and a second end portion 23f corresponding to an end point side for pulling out the expanded diameter holding member 23 as the core ribbon 23c. In the vicinity of the first end portion 23d, an exposed portion 23g is formed in which the inner cold shrink tube 20 is not installed, with the outer circumferential surface of the expanded diameter holding member 23 exposed, and the exposed portion 23g is also formed in the vicinity of the second end portion 23f.

The core ribbon 23c disassembled from the first end portion 23d is, for example, passed through the inner side of the expanded diameter holding member 23 and pulled out from the second end portion 23f side. The core ribbon 23c is pulled out on the second end portion 23f side, and thus the expanded diameter holding member 23 is sequentially disassembled from the first end portion 23d toward the second end portion 23f. In the present embodiment, the core ribbon 23c is formed all over the length in the axial direction, and thus the expanded diameter holding member 23 can be completely disassembled from the first end portion 23d to the second end portion 23f. However, the disassembly line 23b may be formed in at least a portion of the expanded diameter holding member 23 in which the inner cold shrink tube is held with an expanded diameter, and for example, the disassembly line 23b may be absent in a predetermined region on the second end portion 23f side.

The inner cold shrink tube 20 as an example is a member held with an expanded diameter on the outer circumference side of the expanded diameter holding member 23. The inner cold shrink tube 20 covers a portion of the cable 2 located adjacent to the cable connection portion 10. The inner cold shrink tube 20 is formed of, for example, rubber that shrinks at normal temperature and has excellent stretching properties. The inner cold shrink tube 20 may be formed of, for example, a material having waterproof properties. In this regard, “has waterproof properties” refers to a state in which an external liquid can be prevented from entering to inside with the inner cold shrink tube 20 being shrunk. “Has waterproof properties” refers to, for example, IPX7 specified in JIS C 0920 “degree of protection (IP code) provided by enclosure of electrical machinery and equipment” (when the article is immersed in water at a water depth of 1 m for 30 minutes, no water enters inside). The material of the inner cold shrink tube 20 is, for example, Ethylene Propylene Diene rubber (EPDM). FIG. 3(a) is a diagram schematically illustrating the outer cold shrink tube 30. FIG. 3(b) is a cross-sectional view of the outer cold shrink tube 30. As illustrated in FIGS. 1, 3(a) and 3(b), the outer cold shrink tube 30 covers the cable connection portion 10 and the inner cold shrink tube 20. The outer cold shrink tube 30 has a larger diameter (outer diameter and inner diameter) than that of the inner cold shrink tube 20. For example, the outer cold shrink tube 30 has a larger length in the axial direction (longitudinal direction) than that of the inner cold shrink tube 20.

For example, the outer cold shrink tube 30 covers at least a portion of the cable connection portion 10 and at least a portion of the inner cold shrink tube 20. The outer cold shrink tube 30 covers a region that includes a boundary portion B between the cable connection portion 10 and the inner cold shrink tube 20. For example, like the inner cold shrink tube 20, the outer cold shrink tube 30 is formed of a material having waterproof properties. The material of the outer cold shrink tube 30 is, for example, EPDM.

For example, before the outer cold shrink tube 30 covers the cable connection portion 10 and the inner cold shrink tube 20 (before installation and before use), the outer cold shrink tube 30 may be held around an outer circumference of the expanded diameter holding member 33 in a state in which the outer cold shrink tube 33 has an expanded diameter. Similar to the expanded diameter holding member 23 described above, the expanded diameter holding member 33 includes a disassembly line 33b formed in the direction in which the axis L2 extends, and can be pulled out along the disassembly line 33b as a core ribbon 33c that has a string-like body. Similar to the expanded diameter holding member 23 described above, the expanded diameter holding member 33 includes a first end portion 33d corresponding to a start point side for pulling out the expanded diameter holding member 33 as the core ribbon 33 c, and a second end portion 33f corresponding to an end point side for pulling out the expanded diameter holding member 33 as the core ribbon 33c. In the vicinity of the first end portion 33d, an exposed portion 33g is formed in which the outer cold shrink tube 30 is not installed, with the outer surface of the expanded diameter holding member 33 exposed, and the exposed portion 33g is also formed in the vicinity of the second end portion 33f. As described above, the shape and material of the expanded diameter holding member 33 may, for example, be identical to the shape and material of the expanded diameter holding member 23.

As an example, the cable connection portion 10 includes an insulating tube 11, a connector 12, and a semi-conductive tape 13. The insulating tube 11 is configured as a cylindrical body including a hollow portion 1 lb that penetrates the cable 2 in the longitudinal direction Dl. The insulating tube 11 includes, for example, an insulating tube body 1 lc including a hollow portion 1 lb, a shield mesh 1 Id, an impervious layer 1 If, and a waterproof tube 1 lg. The insulating tube body 1 lc is, for example, an integrally molded article of rubber. The insulating tube body 1 lc as an example may include insulating rubber, for example, ethylene propylene rubber or silicone rubber. For example, the insulating tube body 1 lc includes insulating mbber 1 lcl and conductive mbber 1 lc2. The conductive mbber 1 lc2 is provided, for example, at three locations including both end portions of the insulating tube body 1 lc in the longitudinal direction Dl and the center of the insulating tube body 1 lc in the longitudinal direction Dl. The shield mesh l id covers at least a portion of the insulating tube body 1 lc. The impervious layer I lf covers the shield mesh 1 Id. For example, at least a portion of the shield mesh 1 Id is covered with the outer cold shrink tube 30.

For example, the insulating tube 11 covers the connector 12. FIG. 4 is a diagram schematically illustrating the insulating tube 11. As illustrated in FIG. 4, before the connector 12 is covered (before installation and before use), the insulating tube 11 may be held around the outer circumference of the expanded diameter holding member 1 lh in a state in which the insulating tube 11 has an expanded diameter. Similar to the expanded diameter holding member 23 described above, the expanded diameter holding member 1 lh includes a disassembly line 1 lj, and can be pulled out along the disassembly line 1 lj as a core ribbon that has a string-like body. The material of the expanded diameter holding member 1 lh may be, for example, identical to the material of the expanded diameter holding member 23.

The connector 12, for example, connects the conductors 2b extending from the pair of cables 2 opposing each other along the longitudinal direction Dl. FIG. 5 is a perspective view illustrating the connector 12 as an example. As illustrated in FIGS. 1 and 5, the connector 12 is a sleeve to which, for example, a plurality of conductors 2b appropriately crimped and connected. The connector 12 as an example has a tubular shape including an outer circumferential surface 12f including openings 12c respectively formed at both ends of the outer circumferential surface 12f. In this case, the pair of conductors 2b are inserted into the respective openings 12c of the connector 12, and in this state, each conductor of the pair of conductors 2b is appropriately crimped, and thus the pair of conductors 2b are electrically connected to each other inside the connector 12.

As the connector 12, a threaded connector (also referred to as a shear bolt connector) may be used instead of the sleeve described above. In this case, a plurality of threaded holes communicating with the internal space of the connector body are formed on the outer circumferential surface of the tubular connector body, and bolts are screwed into the respective threaded holes to bring the conductors inside the connector body into pressure contact with one another. With the pair of conductors inserted into the connector body through the respective openings, a plurality of bolts are screwed into the respective threaded holes to electrically connect the pair of conductors 2b to each other. In a case where the cable connection portion 10 includes the connector 12, the need for a compression tool can be eliminated, and the pair of conductors 2b can be easily connected. The type of the connector 12 has been described above as an example, but the type of the connector is not particularly limited. Note that the semi-conductive tape 13 is wrapped around the connector 12.

FIGS. 6(a) and 6(b) are perspective views schematically illustrating the shielding treated portion 16 of the cable connection structure 1. FIG. 7 is a cross-sectional view schematically illustrating the layered structure of the cable 2. As illustrated in FIGS. 6(a), 6 (b) and 7, in the cable 2, the conductor 2b, the insulating layer 2c, the semi-conductive layer 2d, the shielding layer 2f, the semi-conductive layer 2g, the impervious layer 2h, and the cable sheath 2j are laminated in this order from inner side of the cable 2 in the radial direction. The shielding treated portion 16 refers to an area in which in the shielding layer 2f, the semi-conductive layer 2g, the impervious layer 2h, and the cable sheath 2j, the piercing terminal 40, the grounding conductor 50, and the grounding spring 60 are provided.

For example, the shielding treated portion 16 includes a portion 17 of the cable sheath 2j and the impervious layer 2h which portion 17 is spaced apart from the shielding layer 2f, and an exposed portion 19 in which the shielding layer 2f is exposed The exposed portion 19 refers to an area where the cable sheath 2j, the impervious layer 2h, and the semi-conductive layer 2g are stripped off to expose the shielding layer 2f. For example, the exposed portion 19 extends in the longitudinal direction D1 of the cable 2 and a circumferential direction D2 of the cable 2. The portion 17 of the cable sheath 2j and the impervious layer 2h which portion 17 is spaced apart from the shielding layer 2f is an area between a pair of cuts 18 aligned along the circumferential direction D2, and includes a portion of the cable sheath 2j and impervious layer 2h which is turned up from the shielding layer 2f. The portion 17 includes, for example, a three-layer structure of the cable sheath 2j, the impervious layer 2h, and the semi-conductive layer 2g.

For example, the shielding treated portion 16 includes a plurality of portions 17 (two as an example) of the cable sheath 2j and the impervious layer 2h which portions 17 are spaced apart from the shielding layer 2f, and the plurality of portions 17 are aligned along the circumferential direction D2. For example, each of the plurality of portions 17 is provided with the piercing terminal 40 and the grounding conductor 50. The piercing terminal 40 and the grounding conductor 50 are installed in order to electrically and mechanically connect the impervious layer 2h and the shielding layer 2f to keep the potential of the impervious layer 2h equal to the potential of the shielding layer 2f. The piercing terminal 40 pierces the cable sheath 2j and the impervious layer 2h and is thus fixed to the portion 17, and the grounding conductor 50 extends from the piercing terminal 40.

For example, the grounding conductor 50 includes a first bending portion 51 extending from the piercing terminal 40 and bending along an inner side 17b of the spaced-apart portion 17, a first extending portion 52 extending along the inner side 17b, a second bending portion 53 bending along the shielding layer 2f at an end portion of the first extending portion 52 opposite to the first bending portion 51 (the inner end portion of the spaced-apart portion 17), and a second extending portion 54 extending from the second bending portion 53 to the exposed portion 19.

The second bending portion 53 is located, for example, at a root side end portion of the portion 17 of the cable sheath 2j and the impervious layer 2h which portion 17 is spaced apart from the shielding layer 2f. However, the second bending portion 53 may be located at a portion (for example, an intermediate portion) other than the root side end portion of the portion 17. The second extending portion 54 extends in the longitudinal direction D1 in the exposed portion 19, and the grounding spring 60 is wrapped around the extending portion For example, the grounding spring 60 clamps a plurality of the grounding conductors 50 (second extending portions 54) to the shielding layer 2f.

As described above, the grounding conductor 50 is installed on the inner side of the cable sheath 2j with bending portions bending in a Z shape being formed (as an example, the first bending portion 51 and the second bending portion 53). The bending portion of the grounding conductor 50 has a length (e.g., the length from the first bending portion 51 to the second bending portion 53) of, for example, 20 mm or more. This allows reliable maintenance of the connection established between the impervious layer 2h and the shielding layer 2f by the grounding conductor 50 even in a case where the cable sheath 2j is subjected to shrink back of 20 mm or less. Additionally, even in a case where the relative positions of the cable sheath 2j and the shielding layer 2f are displaced due to thermal expansion or the like, the bending portion absorbs the displacement to allow reliable maintenance of electrical and mechanical connection between the impervious layer 2h and the shielding layer 2f. Furthermore, the grounding spring 60 clamps the grounding conductor 50 to the shielding layer 2f to allow the connection between the shielding layer 2f and the impervious layer 2h to be made more robust.

FIG. 8 is a perspective view illustrating the piercing terminal 40 to which the grounding conductor 50 as an example is coupled. FIG. 9(a) is a diagram illustrating the piercing terminal 40 as an example. FIG. 9(b) is a diagram illustrating the grounding conductor 50 as an example. FIG. 9(c) is a diagram illustrating the grounding spring 60 as an example. As illustrated in FIGS. 8, 9(a), and 9(b), the piercing terminal 40 may be a Termifoil terminal attached to an end portion of the grounding conductor 50. The piercing terminal 40 as an example includes a first portion 42 including a plurality of blade portions 41 that pierce the cable sheath 2j and the impervious layer 2h, and a second portion 43 that is folded closer to the first portion 42, and a coupling portion 44 coupled to the first portion 42.

The piercing terminal 40 is formed of a conductive material (e.g., metal). For example, the piercing terminal 40 may include at least either nickel plating or tin plating. The first portion 42 and the second portion 43 have, for example, a plate shape. The first portion 42 is, for example, continuous with the second portion 43 via the folded portion 45, and the second portion 43 is folded closer to the first portion 42 via the folded portion 45.

The coupling portion 44 has, for example, a tubular shape (as an example, a cylindrical shape). The grounding conductor 50 is coupled to the coupling portion 44 by, for example, crimping.

Specifically, the coupling portion 44 is appropriately crimped, with the end portion of the grounding conductor 50 being inserted into the coupling portion 44, thus the grounding conductor 50 is coupled to the coupling portion 44. The folded portion 45 extends, for example, along the direction D3 in which the grounding conductor 50 is inserted into the coupling portion 44.

The first portion 42 is located, for example, on an extension of the direction D3 of the coupling portion 44. As an example, the first portion 42 has a rectangular plate shape extending in the direction D3 and in a direction D4 intersecting the direction D3. The first portion 42 includes blade portions 41 that pierce the cable sheath 2j and the impervious layer 2h. The first portion 42 includes, for example, a plurality of through holes 42b penetrating the first portion 42 in a plate thickness direction, and the blade portion 41 protmdes from an edge of each of the through holes 42b. For example, a plurality of (as an example, four) the blade portions 41 may protrude from the through hole 42b. As an example, the piercing terminal 40 includes five blade portions 41. In this case, one of the five blade portions 41 is disposed in the center of the first portion 42, and the remaining four blade portions 41 may be disposed in a square shape. In this way, one of the plurality of blade portions 41 may be disposed in the center of the first portion 42.

For example, the second portion 43 has a rectangular plate shape. For example, like the first portion 42, the second portion 43 includes a plurality of through holes 43b penetrating the second portion 43 in a plate thickness direction, and the blade portion 41 may protrude from the edge of each of the through holes 43b. The second portion 43 includes an opposing surface facing the first portion 42 when the second portion 43 is folded closer to the first portion 42 via the folded portion 45, and for example, the blade portions 41 protrude from the opposing surface. The number of blade portions 41 included in the piercing terminal 40 is, for example, 2 or more and 10 or less. However, the number of blade portions 41 may be 1, 3 or more, 4 or more, 5 or more, or 10 or more, or may be nine or less, 8 or less, 7 or less, or 6 or less.

The grounding conductor 50 has, for example, a flat shape. In this case, the grounding conductor 50 includes the portion 17 included in the cable sheath 2j and the impervious layer 2h and spaced apart from the shielding layer 2f, and a main surface 50b opposing the shielding layer 2f, and an end surface 50c facing in a direction intersecting the main surface 50b. As an example, the grounding conductor 50 extends in a tape shape along the longitudinal direction of the grounding conductor 50, and the main surface 50b has a rectangular shape including long sides extending in the longitudinal direction. The grounding conductor 50 has, for example, a net shape. In this case, the grounding conductor 50 may be a braided wire.

For example, the grounding conductor 50 may be a flat braided wire (as an example, a flat braided copper wire). The grounding conductor 50 may have a length of 100 mm or more and 200 mm or less (as an example, 150 mm). The grounding conductor 50 may have a cross-sectional area of 1.25 mm ² or more and 14 mm ² or less. As an example, the grounding conductor 50 is formed by braiding a plurality of wires including a conductive material. As an example, the wire has a diameter of 0.12 mm, the number of wires constituting the grounding conductor 50 is 490, and thus the grounding conductor 50 has a cross- sectional area of 5.54 mm ² (= 0.0012 mm ² x 490). However, the diameter and number of the wires, and the length and cross-sectional area of the grounding conductor 50 are not limited to the values described above.

The grounding spring 60 is, for example, a constant force spring. For example, the grounding spring 60 has a tape shape. The grounding spring 60 exerts an elastic force in the radial direction of the cable 2 when the grounding spring 60 is wrapped around the shielding layer 2f and the grounding conductor 50. In the example described above, an example has been described in which the cable connection member 100 includes the inner cold shrink tube 20, the outer cold shrink tube 30, the piercing terminal 40, the grounding conductor 50, and the grounding spring 60. However, the cable connection member may include the piercing terminal 40, the grounding conductor 50, and the grounding spring 60, and the components constituting the cable connection member can be changed as appropriate. Now, an example of a method for connecting the cable 2 according to the present embodiment will be described. An example in which two cables 2 are connected will be described below. First, as illustrated in FIG. 10(a), for example, a step of treating the cables is performed. At this time, after terminal treatment is performed on each of the pair of cables 2 by stripping off the cable sheath 2j to expose the conductor 2b and the insulating layer 2c in this order, the conductors 2b of the pair of cable 2 are placed facing each other.

Now, as illustrated in FIGS. 10(b) and 10(c), the step of inserting members into the cable 2 is performed. At this time, the outer cold shrink tube 30 expanded in diameter by the expanded diameter holding member 33 and the inner cold shrink tube 20 expanded in diameter by the expanded diameter holding member 23 are each inserted into each of the pair of cables 2. Then, the insulating tube 11 expanded in diameter by the expanded diameter holding member 1 lh is inserted into any one of the pair of cables 2.

Then, as illustrated in FIG. 11(a), the step of attaching the connector 12 is performed. Specifically, each of the pair of conductors 2b is inserted into each of the openings 12c of the connector 12, and the connector 12 is crimped. In this way, the connector 12 is used to clamp the pair of conductors 2b and to electrically connect the pair of cables 2.

After the connector 12 is used to connect the pair of cables 2, the step of wrapping the semi- conductive tape 13 is performed as illustrated in FIG. 11(b). At this time, the semi-conductive tape 13 is wrapped around the connector 12. For example, the connector 12 is completely covered with the semi- conductive tape 13.

Subsequently, as illustrated in FIGS. 12(a) and 12(b), the step of mounting the insulating tube 11 is performed. Specifically, the insulating tube 11 inserted into the cable 2 is moved, for example, the core ribbon of the expanded diameter holding member 1 lh is pulled out, and the insulating tube 11 is used to clamp the semi -conductive tape 13 and the pair of cables 2. Subsequently, shielding treatment is performed on both ends of the insulating tube 11 in the longitudinal direction D1 to form the shielding treated portion 16.

Above described FIG. 6(a) and FIG. 6(b), and FIGS. 13 and 14 illustrate a specific procedure for forming the shielding treated portion 16. First, as illustrated in FIG. 13, the cable sheath 2j, the impervious layer 2h, and the semi-conductive layer 2g of the cable 2 are stripped off at each end of the insulating tube 11 in the longitudinal direction D1 to form the exposed portion 19 in which the shielding layer 2f is exposed.

Then, cuts 18 are formed in the cable sheath 2j and the impervious layer 2h (on which the semi- conductive layer 2g is laminated) of the cable 2 located on a side of the exposed portion 19 opposite to the insulating tube 11, and the cable sheath 2j and the impervious layer 2h are turned up to form the portion 17 of the cable sheath 2j and the impervious layer 2h which portion 17 is spaced apart from the shielding layer 2f, thus exposing the shielding layer 2f (the step of exposing the shielding layer). At this time, a pair of the cuts 18 aligned along the circumferential direction D2 of the cable 2 are formed, and the portion between the pair of cuts 18 is turned up to form the portion 17 spaced apart from the shielding layer 2f. For example, a plurality of (as an example, two) spaced-apart portions 17 are formed.

On the other hand, the grounding conductor 50 is coupled to the piercing terminal 40 (the step of coupling the grounding conductor to the piercing terminal). As a specific example, one end of the grounding conductor 50 is inserted into the coupling portion 44 of the piercing terminal 40, and the coupling portion 44 in which the grounding conductor 50 is inserted is crimped to couple the grounding conductor 50 to the piercing terminal 40. Then, the piercing terminal 40 pierces the spaced-apart portion 17. At this time, the spaced-apart portion 17 is sandwiched between the first portion 42 and the second portion 43, and the cable sheath 2j and the impervious layer 2h in the portion 17 are pierced with the blade portions 41. As a specific example, with the coupling portion 44 of the piercing terminal 40 disposed at an end portion of the portion 17 in the longitudinal direction Dl, the portion 17 is sandwiched between the first portion 42 and the second portion 43 and pierced with the blade portions 41 to fix the piercing terminal 40 to the portion 17.

After the portion 17 is pierced with the piercing terminal 40 to fix the piercing terminal 40, the grounding conductor 50 is bent such that the grounding conductor 50 extending from the piercing terminal 40 is placed along the inner side 17b of the spaced-apart portion 17 and the shielding layer 2f, as illustrated in FIG. 6(a) (the step of bending the grounding conductor). At this time, a bending portion that bends in a Z shape is formed. As a specific example, the grounding conductor 50 extending from the coupling portion 44 is folded back along the inner side 17b of the portion 17 to form the first bending portion 51 (the step of forming a first bending portion), and the grounding conductor 50 is placed along the inner side 17b of the portion 17 to form the first extending portion 52 (the step of forming a first extending portion). Subsequently, the second bending portion 53 is formed that bends along the shielding layer 2f from the end portion of the first extending portion 52 opposite to the first bending portion 51 (the step of forming a second bending portion), and the grounding conductor 50 is extended from the second bending portion 53 along the shielding layer 2f to form the second extending portion 54 (the step of forming a second extending portion).

The step of bending the grounding conductor 50 as described above is, for example, performed on each of the plurality of spaced-apart portions 17. Subsequently, as illustrated in FIG. 6(a) and FIG. 6(b), the grounding spring 60 is wrapped around the grounding conductor 50 extending along the shielding layer 2f (the step of wrapping the grounding spring). At this time, the grounding spring 60 is wrapped around the grounding conductor 50 extending from the bending portion. As a specific example, the grounding spring 60, which has a tape shape, is installed by wrapping and fixing around the grounding conductor 50. For example, the grounding spring 60 is wrapped around a plurality of the grounding conductors 50

After the grounding spring 60 is wrapped, as illustrated in FIG. 14, the tape T is wrapped after whether the impervious layer 2h and the shielding layer 2f are electrically continuous is checked. Then, as illustrated in FIG. 15(a), the step of mounting the inner cold shrink tube 20 is performed. Specifically, the inner cold shrink tube 20 inserted into each of the pair of cables 2 is moved to each of one side and the other side of the cable connection portion 10 (the position adjacent to the cable connection portion 10). The core ribbon 23c of the expanded diameter holding member 23 of each of the inner cold shrink tubes 20 is pulled out to shrink the inner cold shrink tube 20, and thus the inner cold shrink tubes 20 clamp the one side and the other side of the cable connection portion 10.

Subsequently, the step of mounting the outer cold shrink tube 30 is performed as illustrated in FIG. 15(b). At this time, the outer cold shrink tube 30 inserted into each of the pair of cables 2 is moved to a position where the outer cold shrink tube 30 covers the cable connection portion 10 and the inner cold shrink tube 20. Specifically, the outer cold shrink tube 30 is moved to a position where the outer cold shrink tube 30 covers at least a portion of the cable connection portion 10 and at least a portion of the inner cold shrink tube 20. Then, the core ribbon 33c of the expanded diameter holding member 33 of each of the outer cold shrink tubes 30 is pulled out to shrink the outer cold shrink tube 30. Thus, each of the outer cold shrink tubes 30 covers the one side of the cable connection portion 10 and inner cold shrink tubes 20 in the longitudinal direction D1 of the cable connection portion 10 and the other side of the cable connection portion 10 and inner cold shrink tubes 20 in the longitudinal direction D1 of the cable connection portion 10. Subsequently, a series of steps of connecting the pair of cables 2 together are complete.

Now, the effects of the cable connection method, the cable connection structure 1, and the cable connection member 100 according to the present embodiment will be described. As illustrated in FIG.

6(a) and FIG. 6(b), in the cable connection method, the cable connection structure 1, and the cable connection member 100 according to the present embodiment, the cable sheath 2j and the impervious layer 2h are stripped off to expose the shielding layer 2f located on the inner side of the cable sheath 2j and the impervious layer 2h, and the portion 17 of the cable sheath 2j and the impervious layer 2h which portion 17 is spaced apart from the shielding layer 2f is pierced with the piercing terminal 40 attached with the grounding conductor 50. Thus, when the grounding conductor 50 extending from the piercing terminal 40 is brought into contact with the shielding layer 2f to fix the grounding conductor 50 to the shielding layer 2f, the impervious layer 2h can be electrically and mechanically connected to the shielding layer 2f.

By electrically connecting the shielding layer 2f to the impervious layer 2h, the potential of the impervious layer 2h can be made equal to the potential of the shielding layer 2f, suppressing induction of voltage. Thus, discharge caused by induction of voltage can be suppressed. In addition, by using the piercing terminal 40 and the grounding conductor 50 to connect the impervious layer 2h and the shielding layer 2f, the need for solder connection can be eliminated, allowing the reliability of the connection to be improved. The grounding conductor 50 attached with the piercing terminal 40 can be connected to the shielding layer 2f by piercing with the piercing terminal 40, thus enabling a reduction in the number of components to facilitate the operation for installing the cable connection structure 1. Furthermore, the grounding conductor 50 is disposed in a state of being bent along the cable sheath 2j and the inner side 17b of the impervious layer 2h and the shielding layer 2f, and thus even in a case where thermal expansion or the like occurs, the bent portion can be caused to follow thermal expansion or the like. Consequently, even in a case where thermal expansion or the like occurs, the connection between the impervious layer 2h and the shielding layer 2f can be more reliably maintained, thus allowing the reliability of the connection to be further improved.

The grounding conductor 50 may have a flat shape. In this case, the flat portion of the grounding conductor 0 can be disposed along the outer circumferential surface of the shielding layer 2f, thus allowing the workability of installation of the connection structure to be improved.

The grounding conductor 50 may have a net shape. This enables the stretching properties of the grounding conductor 50 to be improved, thus allowing the grounding conductor 50 to easily follow thermal expansion or the like. Consequently, the reliability of the connection can be further improved.

The cable connection method according to the present embodiment may include the step of wrapping the grounding spring 60 around the grounding conductor 50 extending from the bent portion along the shielding layer 2f. In this case, the grounding conductor 50 can be fixed by wrapping the grounding spring 60 around the grounding conductor 50 contacting the shielding layer 2f. Consequently, the reliability of the connection can be further improved without using solder. Furthermore, the need for a dedicated tool such as a soldering iron can be eliminated, thus allowing high-quality connection reliability to be achieved without depending on a skilled person.

The grounding conductor 50 may have a length of 100 mm or more and 200 mm or less. When the grounding conductor 50 has a length of 100 mm or more, the electncal and mechanical connection between the impervious layer 2h and the shielding layer 2f can be more reliably maintained. When the grounding conductor 50 has a length of 200 mm or less, the grounding conductor 50 can be easily fixed to the shielding layer 2f.

The grounding conductor 50 may have a cross-sectional area of 1.25 mm ² or more and 14 mm ² or less. When the grounding conductor 50 has a cross-sectional area of 1.25 mm ² or more, the strength of the grounding conductor 50 can be increased. When the grounding conductor 50 has a cross-sectional area of 14 mm ² or less, the handling properties of the grounding conductor 50 can be further improved.

In the step of fixing the piercing terminal 40, a plurality of (as an example, two) piercing terminals 40 may be fixed. In this case, the plurality of piercing terminals 40 are fixed, and thus even in a case where the connection at one of the piercing terminals 40 is defective, the connections at the other piercing terminals 40 are maintained. Consequently, the reliability of the connection can be improved, allowing safety to be enhanced.

The piercing terminal 40 may include a blade portion 41 piercing the portion 17 of the cable sheath 2j and the impervious layer 2h which portion 17 is spaced apart from the shielding layer 2f, and the number of blade portions 41 may be 2 or more and 10 or less. When the number of blade portions 41 is 2 or more, the connection of the piercing terminal 40 to the cable sheath 2j and the impervious layer 2h can be strengthened. When the number of blade portions 41 is 10 or less, the configuration of the piercing terminal 40 is simplified, allowing the connection using the piercing terminal 40 to be facilitated.

The embodiments of the cable connection method, the cable connection structure, and the cable connection member according to the present disclosure have been described above. However, the present disclosure can be variously modified without departing from the subject matter recited in the claims. That is, the shape, size, number, and arrangement of each of the cable connection structure and the cable connection member and contents and order of the steps of the cable connection method can be changed as appropriate without departing from the subject matter described above.

For example, in the foregoing embodiments, an example has been described in which the cable connection member includes the piercing terminal 40, the grounding conductor 50, and the grounding spring 60. However, the cable connecting member may include at least one of the piercing terminal 40, the grounding conductor 50, and the grounding spring 60, and the components constituting the cable connection member can be appropriately changed.

The piercing terminal according to the present disclosure may be a piercing terminal attached to the grounding conductor and piercing a portion of the cable sheath and the impervious layer of the cable which portion is spaced apart from the shielding layer. The grounding conductor according to the present disclosure may have a flat shape and a knitted shape, may be attached to a piercing terminal piercing a portion of the cable sheath and the impervious layer of the cable which portion is spaced apart from the shielding layer, and may be bent along the inner side of the spaced-apart potion and the shielding layer. The grounding spnng according to the present disclosure may be wrapped around the grounding conductor that is bent along the inner side of the portion of the cable sheath and the impervious layer, which portion is spaced apart from the shielding layer, and along the shielding layer and is extending from the shielding layer.

In the above-described embodiment, an example has been described in which the grounding spring 60 is wrapped around the grounding conductor 50 to bring the grounding conductor 50 into contact with the shielding layer 2f to fix the grounding conductor 50 to the shielding layer 2f. However, the means for bringing the grounding conductor 50 into contact with the shielding layer 2f to fix the grounding conductor 50 to the shielding layer 2f is not limited to the grounding spring 60. For example, the grounding conductor 50 may be brought into contact with and fixed to the shielding layer 2f by wrapping a braided wire around the grounding conductor 50 extending into the shielding layer 2f, which is a shielding copper tape, and soldering and fixing the braided wire to the shielding layer 2f.

In the above-described embodiment, an example has been described in which the grounding conductor 50 is bent such that the grounding conductor 50 extending from the piercing terminal 40 is placed along the inner side 17b of the spaced-apart portion 17 and the shielding layer 2f. At this time, for example, in a case where the grounding conductor 50 is formed of a stretchable material, the grounding conductor 50 may be bent in a state of being shrunk. In this case, the conformability of the grounding conductor 50 with respect to thermal expansion or the like can be further enhanced. As described above, in the above-described embodiment, an example has been described in which the grounding conductor 50 is a flat braided wire. However, the grounding conductor may be other than a flat braided wire, for example, a braided wire, flat shape metal foil, or a metal wire.

In the above-described embodiment, the cable 2, which is a power cable with a rated voltage of 66 kV or more, has been described as an example. However, the cable connection method, cable connection structure, and cable connection member according to the present disclosure may be applied to a power cable of less than 66 kY.

Now, with reference to FIG. 16(a) and FIG. 16(b), a cable connection method and a cable connection structure according to a modified example will be described. FIGS. 16(a) and 16(b) illustrate a shielding treated portion 76 of the cable connection structure according to the modified example. In the shielding treated portion 76, the piercing terminal 40 is fixed in a state in which the piercing terminal 40 is piercing the cable sheath 2j and the impervious layer 2h, and the grounding conductor 50 extends from the piercing terminal 40.

The shielding treated portion 76 differs from the shielding treated portion 16 described above in that the grounding conductor 50 extending from the piercing terminal 40 does not extend along the inner side 17b of the spaced-apart portion 17. In the shielding treated portion 76, the grounding conductor 50 includes the first bending portion 51 that extends from the piercing terminal 40 and that bends toward the inner side of the piercing terminal 40 (the inner side of the cable 2 in the radial direction), the second bending portion 53 that extends from the first bending portion 51 in the longitudinal direction D1 and that bends on the inner side of the piercing terminal 40, and the second extending portion 54 that extends from the second bending portion 53 to the exposed portion 19. The second bending portion 53 is located, for example, below the piercing terminal 40. The second extending portion 54 extends in the longitudinal direction D1 in the exposed portion 19, and the grounding spring 60 is wrapped around the extending portion. In the grounding conductor 50 according to a modified example, a bending portion bending in a Z shape (the first bending portion 51 and the second bending portion 53) is exposed on the shielding layer 2f.

For a cable connection method according to a modified example, after the piercing terminal 40 is fixed to the end portion of the portion 17 of the cable sheath 2j and the impervious layer 2h which portion is spaced apart from the shielding layer 2f, the grounding conductor 50 extending from the piercing terminal 40 is folded back to form the first bending portion 51 (the step of forming a first bending portion). Subsequently, the second bending portion 53 is formed that bends along the shielding layer 2f below the piercing terminal 40 (the step of forming a second bending portion). The grounding conductor 50 is then extended from the second bending portion 53 along the shielding layer 2f to form the second extending portion 54 (the step of forming a second extending portion). Subsequently, the grounding spring 60 is wrapped around the second extending portion 54 extending along the shielding layer 2f (the step of wrapping the grounding spring). After the grounding spring 60 is wrapped, the tape T is wrapped after whether the impervious layer 2h and the shielding layer 2f are electrically continuous is checked. The cable connection structure and the cable connection method according to the modified examples described above can produce effects similar to the effects of the shielding treated portion 16 described above. Note that in the modified examples described above, an example has been described in which the Z-shaped bending portion (second bending portion 53) of the grounding conductor 50 is located on the inner side of the piercing terminal 40 (the inner side of the cable 2 in the radial direction). Elowever, as illustrated in FIG. 17, in the shielding treated unit 86, the Z-shaped bending portion of the grounding conductor 50 need not be located on the inner side of the piercing terminal 40 (Z-shaped bending portion is exposed at the shielding layer 2f). In the shielding treated portion 86, the grounding conductor 50 includes the first bending portion 51 that extends from the piercing terminal 40 and that bends toward the inner side (shielding layer 2f side) at a position spaced apart from the piercing terminal 40, the second extending portion 53 that extends from the first bending portion 51 toward the piercing terminal 40 and that bends toward the inner side at a position spaced apart from the piercing terminal 40, and the second extending portion 54 that extends from the second bending portion 53 to the exposed portion 19. Even the shielding treated portion 86 produces effects similar to effects of the shielding treated portions 16 and 76 described above.

Examples

Now, examples of the cable connection method, the cable connection structure, and the cable connection member will be described. Note that the present disclosure is not limited to the examples given below. First, as illustrated in FIGS. 9(a), 9(b), and 9(c), in the examples, the piercing terminal 40, the grounding conductor 50, and the grounding spring 60 were prepared In the present example, the piercing terminal 40 is a piercing connector (Termifoil, manufactured by Tyco Electronics Japan G.K.), the grounding conductor 50 had a cross-sectional area of 5.5 mm ² and a length of 150 mm. As the grounding spring 60, a constant force spring manufactured by 3M was used.

As illustrated in FIGS. 6(a) and 6(b), the above piercing terminal 40, the grounding conductor 50, and the grounding spring 60 were installed in the cable 2 of 66 kV. Specifically, two portions 17 of the cable sheath 2j and the impervious layer 2h of the cable 2 which portions 17 are spaced apart from the shielding layer 2f were formed, each of the portions 17 was pierced with the piercing terminal 40, and the grounding conductor 50 was bent along the inner side 17b of the portion 17 and the shielding layer 2f. Then, the grounding spring 60 was wrapped around two grounding conductors 50 extending in the shielding layer 2f, the tape T was wrapped around as illustrated in FIG. 14, and whether the impervious layer 2h and the shielding layer 2f was electrically continuous was checked. The cable connection structure according to the example was formed through the steps described above. In contrast, a cable connection structure of a comparative example was formed as follows.

(Comparative Example)

The cable 2 identical to that in the example was used. In the comparative example, the semi- conductive layer 2g was stripped off from the shielding layer 2f and the semi-conductive layer 2g was turned up, and then a flat braided wire was soldered to the semi -conductive layer 2g. Subsequently, the flat braided wire extending above the shielding layer 2f was loosened and then the flat braided wire was fixed using the grounding spring.

Three samples for each of the cable connection structures in the example and the comparative example described above were prepared, and for each sample, a load was applied to the cable sheath 2j to reciprocate the cable sheath 2j approximately 10 mm along the longitudinal direction Dl. The cable sheath 2j was reciprocated five times.

The results of the experiment described above indicate that with the cable connection structure with soldering of the flat braided wire in the comparative example, five reciprocations described above resulted in falloff of solder in all of the three samples. In contrast, in the cable connection structure with the piercing terminal 40 and the grounding conductor 50 in the example, even with five reciprocations described above, no disconnection occurred in three samples. This indicates that in the example using the piercing terminal 40 and the grounding conductor 50, even in a case where the cable 2 is subjected to reciprocation such as thermal shrinkage, high conformability can be achieved, allowing connection reliability to be enhanced. In other words, in the example, an excess length portion of the grounding conductor 50 connecting the impervious layer 2h and the shielding layer 2f is housed in a folded state, thus even in a case where shrink back of the cable sheath 2j or core movement (movement of a portion located further on the inner side than the shielding layer 2f) of the cable 2 occurs, connection can be reliably maintained due to high conformability.

Now, another example of the structure of the grounding conductor in the cable connection structure 1 according to an embodiment will be described with reference to FIG. 18. The cable connection structure 1 includes, in addition to the grounding conductor 50 illustrated in FIG. 14 (which may be referred to as the impervious layer grounding conductor 50 for distinction), a shielding layer grounding conductor 90 in FIG. 18. The impervious layer grounding conductor 50 is a grounding conductor for grounding the impervious layer 2h, whereas the shielding layer grounding conductor 90 is a grounding conductor for grounding the shielding layer 2f. The shielding layer grounding conductor 90 is used to reduce the potential of the shielding layer 2f. For example, in an electric line with a large line length, the shielding layer 2f of the cable 2 has an increased potential, and thus the shielding layer grounding conductor 90 is used to pull out the grounding conductor at an intermediate connection portion and connect the grounding conductor to a grounding electrode. FIG. 18 illustrates both the impervious layer grounding conductor 50 and the shielding layer grounding conductor 90. However, in another aspect, only one of the impervious layer grounding conductor 50 and the shielding layer grounding conductor 90 may be provided. In other words, (1), in a case where a cable including an impervious layer is used and the potential of the cable shielding layer need not be reduced, only the impervious layer grounding conductor 50 is necessary. (2) In a case where a cable including an impervious layer is used and the potential of the cable impervious layer is to be reduced, then both the impervious layer grounding conductor 50 and the shielding layer grounding conductor 90 are used. (3) In a case where a cable with no impervious layer is used and the potential of the cable shielding layer is to be reduced, then only the shielding layer grounding conductor 90 is necessary. In FIG. 19 and subsequent figures, the impervious layer grounding conductor 50 is omitted, but the description covers both the case in (2) and the case in (3) in common.

FIG. 19 illustrates a cross-section. The shielding layer grounding conductor 90 extends from a bent portion P toward a side opposite to the grounding spring 60 The configuration of the shielding layer grounding conductor 90 is, for example, similar to the configuration of the grounding conductor 50. As an example, the shielding layer grounding conductor 90 is a flat braided wire. The cable connection structure

1 includes a first ground lead-out portion 70 at which the shielding layer 2f and the shielding layer grounding conductor 90 are connected, and a second ground lead-out portion 80 extending from the first ground lead-out portion 70 to a side opposite to the bent portion P and connected to a terminal 82.

The first ground lead-out portion 70 is a portion where the shielding layer grounding conductor 90 connects to the shielding layer 2f of the cable 2, and the shielding layer grounding conductor 90 is pressed by the grounding spring 60. The inner cold shrink tube 20 is an impervious layer built-in tube, and the first ground lead-out portion 70 is provided on the inner side of the impervious layer of the inner cold shrink tube 20. For example, the impervious layer of the inner cold shrink tube 20 is metal foil formed of a metal material such as aluminum. In this case, when stress is concentrated in the impervious layer of the inner cold shrink tube 20, a hole may be formed in the impervious layer. Consequently, the first ground lead-out portion 70 has a flat shape with no recesses or protrusions to prevent stress concentration in the impervious layer of the inner cold shrink tube 20.

The second ground lead-out portion 80 is a portion that includes the shielding layer grounding conductor 90 protruding from the inner cold shnnk tube 20, and at which the shielding layer grounding conductor 90 extending from the first ground lead-out portion 70 in the longitudinal direction of the cable

2 connects to the terminal 82. The second ground lead-out portion 80 is provided with a grounding conductor lead-out protection portion 81 that protects the pulled-out shielding layer grounding conductor 90, and a terminal 82 connected to the shielding layer grounding conductor 90 and a metal member 83 that extends from the terminal 82 to a side opposite to the shielding layer grounding conductor 90. As an example, the grounding conductor lead-out protection portion 81 includes a tape 81b that covers the exposed shielding layer grounding conductor 90 and attached to the terminal 82, and a waterproof tube

8 lc that covers the cable 2 and the tape 8 lb. For example, the tape 8 lb is an adhesive polyethylene tape, and the waterproof tube 8 lc is formed of EPDM. The waterproof tube 8 lc is a tube with no impervious layer. As an example, the waterproof tube 81c is a cold shrink tube.

A portion of the second ground lead-out portion 80 that does not include the inner cold shrink tube 20 corresponds to a portion for which the stress on the impervious layer of the inner cold shrink tube 20 need not be taken into account, and may thus include recesses and protmsions. The terminal 82 and the metal member 83 are disposed in a position away from the inner cold shrink tube 20. For example, the terminal 82 is joined to the metal member 83 using a bolt and a nut 84. As an example, an area where the terminal 82 and the bolt and nut 84 are provided protmdes from the cable 2.

The metal member 83 is formed of, for example, copper. As an example, the metal member 83 has a plate shape. For example, the metal member 83 includes a connection portion 83b connected to the terminal 82 and covered with the grounding conductor lead-out protection portion 81, and an extending portion 83c that is not covered with the grounding conductor lead-out protection portion 81 and that extends from the connection portion 83b toward the outer side of the grounding conductor lead-out protection portion 81. The connection portion 83b corresponds to a portion of the metal member 83 at the terminal 82 side that is connected to the terminal 82 via the bolt and nut 84.

As an example, the connection portion 83b extends substantially parallel to the cable 2. A putty material 85 (as an example, butyl putty) may be provided between the connection portion 83b and the grounding conductor lead-out protection portion 81 (tape 81b) and between the connection portion 83b and the cable 2. Additionally, the connection portion 83b may be spaced apart from the cable 2. The extending portion 83c extends obliquely toward the outer side in the radial direction of the cable 2 while extending away from the connection portion 83b.

Now, a method for assembling the cable connection structure 1 including the first ground lead- out portion 70 and the second ground lead-out portion 80 will be described. First, as illustrated in FIG.

20, with the insulating tube 11 of the cable connection portion 10 attached to the cable 2, the shielding layer grounding conductor 90 is fixed to the shielding layer 2f of the cable 2 using the grounding spring 60, and the shielding layer grounding conductor 90 is pulled out (the step of forming a first ground lead- out portion). Then, the bent portion P is formed. The portion P has an extra length to allow the shielding layer grounding conductor 90 to follow expansion and shrinkage of the cable 2 when the cable is expanded or shrunk in the longitudinal direction due to thermal expansion or shrinkage.

The inner cold shrink tube 20 is installed to cover the bent portion P of the shielding layer grounding conductor 90 as illustrated in FIG. 21. Then, the terminal 82 is connected to a portion of the shielding layer grounding conductor 90 that extends from the inner cold shrink tube 20, and the terminal 82 is connected to the metal member 83 using the bolt and nut 84 (the step of forming a second ground lead-out portion). At this time, the putty material 85 may be attached between the metal member 83 and the cable 2.

Subsequently, for example, the putty material 85 is attached on the metal member 83, and the tape 8 lb is wrapped around the connection portion 83b of the metal member 83, the terminal 82, and the exposed portion of the shielding layer grounding conductor 90 (the step of wrapping the tape to the exposed portion of the shielding layer grounding conductor). As illustrated in FIGS. 19 and 22, the tape 8 lb is covered with the waterproof tube 8 lc (the step of covering with the waterproof tube). After the grounding conductor lead-out protection portion 81 is attached as described above, the cable connection structure 1 illustrated in FIG. 19 is complete, and a series of steps of assembling the cable connection structure 1 is complete. Now, a modified example of the cable connection structure including the first ground lead-out portion 70 and the second ground lead-out portion 80 will be described. Descriptions overlapping with those in the embodiments described above are hereinafter omitted as appropriate. As illustrated in FIG.

23, the cable connection structure 1 A according to the modified example includes a grounding conductor lead-out protection portion 81 A different from the grounding conductor lead-out protection portion 81. The grounding conductor lead-out protection portion 81A differs from the grounding conductor lead-out protection portion 81 in that the grounding conductor lead-out protection portion 81A includes no waterproof tube. For example, the grounding conductor lead-out protection portion 81 A includes a self fusing tape 8 Id bonded to the terminal 82, and a tape 8 If that covers the self-fusing tape 8 Id. As an example, the tape 8 If is an adhesive polyethylene tape.

Now, a further modified example of the cable connection structure including the first ground lead-out portion 70 and the second ground lead-out portion 80 will be described. As illustrated in FIG. 24, a cable connection structure IB according to the modified example does not include the terminal 82 and includes a metal member 83B different from the metal member 83. The metal member 83B includes the terminal portion 83d in addition to the connection portion 83b and the extending portion 83c described above. The terminal portion 83d is located at the shielding layer grounding conductor 90 side end portion of the connection portion 83b, and functions as a terminal to which the shielding layer grounding conductor 90 is connected.

As illustrated in FIGS. 24 and 25, for example, the terminal portion 83d of the metal member 83B has a tubular shape protruding from the connection portion 83b having a plate shape. In this case, the shielding layer grounding conductor 90 is inserted into the inner side of the terminal portion 83d having a tubular shape, and the shielding layer grounding conductor 90 is pressure-bonded inside the terminal portion 83d to connect the shielding layer grounding conductor 90 to the metal member 83B. In this manner, in the cable connection structure IB according to the modified example, instead of the terminal 82, the terminal portion 83d integrated with the metal member 83 is connected to the shielding layer grounding conductor 90. This allows elimination of the need for the bolt and nut 84, and enables a reduction in the number of components.

In the cable connection structures 1, 1A, and IB including the first ground lead-out portion 70 and the second ground lead-out portion 80, the shielding layer grounding conductor 90 includes the first ground lead-out portion 70 connected to the shielding layer 2f and the second ground lead-out portion 80 extending from the first ground lead-out portion 70 in the longitudinal direction of the cable 2 to a position where the second ground lead-out portion 80 is connected to the terminal, and the first ground lead-out portion 70 is provided on the inner side of the impervious layer of the inner cold shrink tube 20, which is an impervious layer built-in tube. Accordingly, formation of recesses and protrusions on the first ground lead-out portion 70 can be suppressed, thus allowing suppression of wrinkling of the impervious layer of the inner cold shrink tube 20. As a result, formation of a hole in the impervious layer can be more reliably suppressed. Additionally, the second ground lead-out portion 80 located on the outer side of the inner cold shrink tube 20 is covered with the grounding conductor lead-out protection portion 81 or 81 A, thus allowing protection of the second ground lead-out portion 80 located on the outer side of the inner cold shrink tube 20.

Various examples of the cable connection structure including the first ground lead-out portion and the second ground lead-out portion have been described above. However, the structures of the first ground lead-out portion and the second ground lead-out portion are not limited to the examples described above, and various modifications can be made. For example, in the examples described above, the second ground lead-out portion 80 has been described that includes the grounding conductor lead-out protection portion 81, the terminal 82, the metal member 83, the bolt and nut 84, and the putty material 85. However, the components constituting the second ground lead-out portion are not limited to the examples described above, and can be changed as appropriate. The same applies to the first ground lead-out portion.