JP7256060B2 - Branch connection part and branch connection method of litz wire - Google Patents

Description

TECHNICAL FIELD The present invention relates to a branch connection portion of a litz wire and a branch connection method.

In general, power facilities such as power stations and substations are equipped with fault currents and fault currents that flow into the grounded body to protect the building structures and electrical equipment (hereinafter referred to as the "grounded body") from ground faults and lightning strikes. A grounding system is provided to release and spread lightning currents (surge currents) to earth. A grounding system includes a ground wire that electrically connects a grounded object to the earth and carries ground fault currents and lightning currents. The ground line is electrically connected to, for example, a ground electrode buried in the ground.

Conventional grounding systems are designed and constructed based on the characteristics of low frequencies (direct current, commercial frequency) that flow during a ground fault. An IV wire (vinyl insulated wire) in which vinyl insulation is applied to a cable conductor is used. In this case, due to the influence of the skin effect and the like, the impedance increases when current in a high frequency band flows. Therefore, when a lightning surge current containing high-frequency components of 100 kHz to 1 MHz is applied, the potential of the grounding system increases greatly, and there is a risk of failure (for example, equipment damage or malfunction) occurring in the grounded object.

In particular, in recent years, ICT (Information and Communication Technology) has been introduced for power equipment control and remote monitoring, and ICT equipment is being used for control. Therefore, it is required to improve the lightning resistance of the grounding system.

By using Litz wire as the ground wire of the ground system, the above requirements can be met. In order to facilitate the formation of grounding nets and raised wires for grounding systems, the ends of litz wires are often equipped with metal terminals for branching (see Patent Documents 1 to 3, for example). According to the techniques disclosed in Patent Documents 1 to 3, it is possible to easily achieve electrically and mechanically stable quality.

JP 2019-23983 A Japanese Patent No. 6427613 Japanese Patent No. 6423465

However, the techniques disclosed in Patent Literatures 1 to 3 use, as metal terminals, exclusive products having a special structure developed for branch connection of litz wires, so there is a risk of an increase in construction costs. Specifically, when configuring a branch connection of a litz wire using the technique disclosed in Patent Document 1, a dedicated metal terminal having a special structure, a lead wire corresponding to the number of branches, and a C-shaped cross-sectional connector is required, and the number of parts has increased.

SUMMARY OF THE INVENTION An object of the present invention is to provide a litz wire branch connection part and a branch connection method that can easily and inexpensively realize stable quality electrically and mechanically.

The branch connection part of the litz wire according to the present invention is
two litz wires formed by twisting a plurality of strands each having an insulating film applied to the outer peripheral surface of the conductor;
a branch sleeve that mechanically connects the two litz wires by gripping and crimping them along the longitudinal direction without removing the insulating coating,
In a state in which the two litz wires are mechanically connected by the branch sleeve, a portion connected by the branch sleeve is straddled over the two litz wires so as not to penetrate the branch sleeve in the drilling direction. The two litz wires are electrically connected by filling the solder filling hole with solder.

A branch connection method for a litz wire according to the present invention includes:
Two litz wires obtained by twisting a plurality of strands of conductors each having an insulating coating on the outer peripheral surface are held by a branch sleeve in a state in which they are arranged along the longitudinal direction without removing the insulating coating. a step of mechanically connecting by crimping;
a step of forming a solder filling hole across the two litz wires in the portion connected by the branch sleeve so as not to penetrate the branch sleeve in the drilling direction;
and filling the solder filling hole with solder to electrically connect the two litz wires.

ADVANTAGE OF THE INVENTION According to this invention, the branch connection part of the litz wire which has stable quality electrically and mechanically can be implement|achieved easily and cheaply.

FIG. 1 is a diagram showing the configuration of a grounding system. 2A to 2C are diagrams showing examples of ground lines. FIG. 3 is a diagram showing an example of a branch connection in a ground system. FIG. 4 is an external perspective view showing an example of a branch sleeve. 5A and 5B are cross-sectional views of the branch connection. 6A-6C are diagrams showing a method of constructing a branch connection. FIG. 7 is a diagram showing another example of the branch connection. FIG. 8 is a diagram showing another example of the branch connection. FIG. 9 is a diagram showing another example of the branch connection.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing the configuration of a grounding system 1. As shown in FIG.
The grounding system 1 is provided as ancillary equipment in and around power facilities such as power plants and substations. A fault current or lightning current (surge current) that has flowed into the body 20 is released to the ground and diffused.
As shown in FIG. 1, the grounding system 1 includes a grounding wire EW that electrically connects a grounded object 20 and the ground and carries a ground fault current, a lightning current, or a shielding current. The ground wire EW is electrically connected to a ground electrode 11 buried in the ground. In the branch connections B1 to B4 of the ground wire EW of the ground system 1, the branch connections of the litz wire according to the present invention are applied.

The ground wire EW forms a ground network 12, a riser wire 13 and a pole connection wire 14. FIG. The ground network 12 has a structure in which a plurality of ground wires EW are arranged in a lattice at predetermined intervals (for example, 4 m), and is buried in the ground in a substantially horizontal state. The ground network 12 may have a configuration in which the ground wires EW are arranged in a ring. The ground network 12 has a size that covers substantially the entire construction area of the power plant. The grounded object 20 is electrically connected to the ground network 12 via the rising wire 13 . The ground network 12 is electrically connected to the ground pole 11 via a pole connection line 14 . By providing the ground network 12, equal potential can be achieved.

In the present embodiment, a litz wire is used as the ground wire EW, which is obtained by collecting and twisting a plurality of element wires (enameled wires) each having a conductor covered with an insulating film. 2A to 2C are cross-sectional views showing an example of the ground wire EW.

The ground wire EW1 shown in FIG. 2A has a configuration in which a plurality of strands 100 (20 in FIG. 2A) are assembled and twisted.

The wire 100 is an enameled wire having a finished outer diameter of about 0.45 mm, which is obtained by baking an insulating film 102 onto a conductor 101 made of, for example, annealed copper. For example, polyvinyl formal, polyurethane, polyurethane nylon, polyester, polyester nylon, polyester imide, polyamide imide, polyester imide/polyamide imide, polyimide, etc. are applied to the insulating film 102 . Note that the ground wire EW1 shown in FIG. 2A is a set twist of enameled wires, and the twist direction is either S (right) twist or Z (left) twist. 5 mm.

The ground wire EW2 shown in FIG. 2B uses a litz wire as shown in FIG. (FIG. 2B for a conductor with a nominal cross-sectional area of 60 mm ² ). The primary strand 103 is also called a child strand and the secondary strand 104 is also called a parent strand.

In FIG. 2B, the secondary strand 104 as the parent strand has a 1-bundle, 6-bundle, and 12-bundle concentric stranded structure from the center outward. Here, the most central side of the concentric twist is called the first twisted layer, and when there are multiple twisted layers, hereinafter, the second, third, and fourth twisted layers are called in order toward the outside. In FIG. 2B, six bundles concentrically twisted on the outside of one central bundle are the first twisted layer 104a, and the outer twelve bundles are the second twisted layer 104b.

The twist direction of strands 100 forming primary twisted wire 103 is preferably opposite to the twist direction of a bundle of primary twisted wires 103 in each twisted layer of secondary twisted wire 104 . In other words, the twist directions of the parent twist and the child twist are preferably opposite.

The case where the secondary strands 104 are concentrically stranded, as in the case of FIG. 2B, will be specifically described. First, the twist direction of the outermost layer of the twisted wire is preferably S (right) twist in order to conform the ground wire to the JIS standard. Therefore, in the configuration of FIG. 2B, the second twisted layer 104b is the outermost layer of the secondary twisted wires 104, so the twist direction of the bundle of the primary twisted wires 103 in the second twisted layer 104b, which is the outermost layer, is S (right ) is twisted. In this case, the twisting direction of the strands 100 of each primary twisted wire 103 constituting the second twisted layer 104b (the twisting direction of each child twist of 12 bundles) is a Z (left) twist opposite to the parent twist. is preferred.

On the other hand, the twist direction of the bundle of the primary twisted wires 103 in the first twisted layer 104a of the secondary twisted wires 104 is preferably a Z twist opposite to the twisting direction (S twist) in the second twisted layer 104b. In this case, the twisting direction of the strands 100 of each primary twisted wire 103 constituting the first twisted layer 104a (the twisting direction of each child twist of 6 bundles) is preferably S-twisted in the opposite direction to the parent twist. . Similarly, the twist direction of the strands 100 of the primary twisted wire 103 constituting one bundle at the center of the secondary twisted wire 104, on which the first twisted layer 104a is formed on the outer side, is the same as that in the first twisted layer 104a. It is preferable to set the S twist in the direction opposite to the parent twist. Thus, the S-twist and Z-twist are determined on the basis that the outermost layer of the twisted wire is S-twisted.

When the secondary twisted wire 104 has one (second twisted layer 104b) or a plurality of twisted layers (third twisted layer or more) outside the first twisted layer 104a, the adjacent twisted layer ( For example, the twist directions of the bundles of the primary twisted wires 103 in the first twisted layer 104a and the second twisted layer 104b) are preferably opposite to each other. That is, when the secondary twisted wire is formed of a plurality of twisted layers, the twisting direction is alternately opposite for each twisted layer (for example, the first twisted layer: Z twist, the second twisted layer: S twist, the third Twisted layer: Z-twisted, . . . ).

Furthermore, the twist direction (direction of each child twist) of the strands 100 of each primary twisted wire 103 constituting each twist layer is different from the twist direction (direction of parent twist) of the bundle of the primary twisted wires 103 in that twist layer. It is preferably formed in the opposite direction (for example, the child twist in a twisted layer in which the parent twist is a Z twist is an S twist).

Thereby, the ground wire EW2 can be made flexible. In addition, by alternately reversing the direction, it is easy to form a concentric twist, and the finished outer diameter can be stabilized. The finished outer diameter of the ground wire EW2 shown in FIG. 2B is approximately 12.3 mm.

The ground wire EW3 shown in FIG. 2C is a jacketed litz wire in which a separator 105 is interposed to form a jacket 106 on the litz wire (secondary stranded wire 104) as shown in FIG. 2B. For example, a nylon film or the like is applied to the separator 105 . Fire-resistant crosslinked polyethylene or the like is applied to the jacket 106, for example. The ground wire EW3 is used for a portion exposed to the ground (for example, the rising wire 13 and the indoor wiring of the ground network 12). The finished outer diameter of the ground wire EW3 shown in FIG. 2C is approximately 15.5 mm.

Note that the outer diameter, the number of twists, etc. of the wire 100 constituting the ground wire EW (EW1 to EW3) are not limited to those shown in the embodiment, and can be arbitrarily selected. In addition to copper, the conductor 101 of the wire 100 may be made of copper alloy, aluminum, aluminum alloy, or a clad material having a double structure of these (for example, copper clad aluminum).

In the grounding system 1, when an alternating current flows through the grounding wire EW, the higher the frequency, the higher the current density on the surface of the conductor compared to the inside of the conductor, and the smaller the effective cross-sectional area of the conductor, resulting in an increase in impedance ( skin effect). The litz wire used for the grounding wire EW has a structure in which each of the wires with a small diameter is insulated. increase can be suppressed. In addition, by using a litz wire for the grounding wire EW, the grounding wire EW can be easily bent when the grounding wire EW is arranged in a grid pattern or a ring shape, and the workability when laying the grounding wire EW is improved. It is remarkably improved as compared with the conventionally used IV line.

FIG. 3 is a diagram showing a branch connection B2 in the grounding system 1. As shown in FIG. FIG. 4 is an external perspective view showing an example of the branch sleeve 15. As shown in FIG. 5A is a cross-sectional view taken along line XX in FIG. 3, and FIG. 5B is a cross-sectional view taken along line YY in FIG. 5A.

As shown in FIG. 3 and the like, two ground wires 121 and 122 of the ground wires EW forming the ground network 12 are connected by the branch sleeve 15 at the branch connection portion B2.
Ground wires EW1 to EW3 shown in FIGS. 2A to 2C are applied to the ground wires 121 and 122, for example. When applying the ground wire EW3 shown in FIG. 2C, the jacket 106 and the separator 105 are removed in advance.
The branch sleeve 15 is composed of, for example, a general-purpose sleeve (also called a T-shaped connector, a C-shaped connector, or a C-shaped metal fitting) having a C-shaped cross section as shown in FIG. The branch sleeve 15 defines the cross-sectional area of the connectable wire and the like. The branch sleeve 15 holds a plurality of wires in a bundled state, and mechanically connects the wires by caulking (compression in the present embodiment).

In the present embodiment, the ground wires 121 and 122 are mechanically connected by gripping and compressing the branch sleeve 15 while extending the ground wires 121 and 122 along the longitudinal direction. A solder filling hole 16 is formed across the ground lines 121 and 122, and the ground lines 121 and 122 are electrically connected by filling the solder filling hole 16 with the solder 17. .

6A to 6C are diagrams showing a construction method of the branch connection portion B2 (branch connection method of litz wire).
First, as shown in FIGS. 6A and 6B, the branch sleeve 15 is attached to the portion where the ground wires 121 and 122 are bundled, and is compressed by a compression tool (not shown). Thereby, the mechanical strength of the ground wires 121 and 122 and the branch sleeve 15 is ensured. At this time, since the insulating film 102 of the ground wires 121 and 122 is not removed, the ground wires 121 and 122 are not electrically connected.

Next, as shown in FIG. 6C, solder filling holes 16 are formed radially from the peripheral surface of the branch sleeve 15 . The solder filling hole 16 is formed by, for example, a punch such as an electric drill. At this time, the solder filling hole 16 is formed so as to straddle the ground wires 121 and 122 and not penetrate the branch sleeve 15 in the radial direction.
In this embodiment, the center of the solder filling hole 16 is formed so as to pass through the contact portion of the ground wires 121 and 122, that is, the boundary in the parallel arrangement direction (direction perpendicular to the longitudinal direction). The hole 16 evenly straddles the ground lines 121 and 122 within the drilling plane. The solder filling hole 16 is formed from a portion where the ends of the C-shaped cross section of the branch sleeve 15 (ends in the circumferential direction of the arc) are in contact with each other due to compression.

Here, "to straddle the ground wires 121 and 122" means to straddle the solder filling hole 16 in at least one of the radial direction and the axial direction. In other words, both ground lines 121 and 122 need only be partially cut by forming the solder filling hole 16 .
By forming the solder filling hole 16, the wires 100 of the ground wires 121 and 122 at the position of the solder filling hole 16 are cut or cut in the drilling direction, and the conductor 101 ( The portion without the insulating film 102) is exposed.

Further, "not to penetrate the branch sleeve 15 in the radial direction" means that one end of the solder filling hole 16 is closed. For example, when the tip of the punch passes through the grounding wires 121 and 122 and reaches a portion on the opposite side of the branch sleeve 15 from the punch start portion, the branch sleeve 15 is pierced in the radial direction. A solder filling hole 16 is formed without solder. Whether or not the tip of the punch has reached the branch sleeve 15 can be confirmed, for example, by drilling while visually checking the tip portion of the solder filling hole 16 .

Next, as shown in FIG. 6D, solder 17 is filled into solder filling hole 16 . As for the method of filling the solder 17 , in the embodiment, the rod-shaped solder 17 is placed in the solder filling hole 16 and heated to melt the solder 17 and fill the solder filling hole 16 . As a result, the conductors 101 of the ground wires 121 and 122 cut and exposed by the solder filling holes 16 are electrically connected via the solder 17 . Since the solder filling hole 16 does not penetrate the branch sleeve 15 in the radial direction, the filled solder 17 is properly filled into the solder filling hole 16 without leaking to the outside. The branch connection portion B2 is assembled through the above steps.
When the solder 17 is poured, it is preferable to heat the branch sleeve 15 before the solder 17 is poured into the solder filling hole 16 . As a result, the mechanical properties and electrical properties of the solder 17 can be improved.

Here, if the size (aperture) of the solder filling hole 16 is too large, most of the ground wires 121 and 122 will be broken, resulting in deterioration of mechanical properties. On the other hand, if the size of the solder filling hole 16 is too small, less conductor 101 is exposed by forming the solder filling hole 16, resulting in increased electrical resistance. Therefore, the number and size of the solder filling holes 16 are appropriately set in consideration of the mechanical properties (eg, tensile strength) and electrical properties (eg, electrical resistance) of the branch connection portion B2.

In particular, considering the twist pitch of the ground wires 121 and 122, the number, size and drilling direction of the solder filling holes 16 are set so that most of the conductors 101 of the wires 100 are exposed and the solder 17 to be filled is exposed. can be electrically connected via Specifically, considering the twist pitch of the ground wires 121 and 122, it is preferable to provide at least two solder filling holes 16A at positions separated from each other in the longitudinal direction of the ground wires 121 and 122 (see FIG. 7). , see FIG. 8).

When at least two solder filling holes 16A and 16B are provided at spaced apart positions, the distance between the centers of the two solder filling holes 16A and 16B is W (mm), and the outermost layer of the two connecting ground wires 121 and 122 is If the twist pitch of is L (mm),
L×(1/3)≦W≦L×(2/3)
It is preferable to satisfy the relationship of
In other words, the conductor of the ground wire 121 (122) is rotated 120° to 240° with respect to the wire 100 (enameled wire) connected via the solder 17A filled in one solder filling hole 16A. It is preferable that the wires 100 on one side are connected through the solder 17B filled in the solder filling hole 16B on the other side. If the positional relationship of the wires 100 connected via the solders 17A and 17B is less than 120° or exceeds 240° in rotation angle, the number of the wires 100 electrically connected by the solders 16A and 16B is insufficient. This is because the electrical resistance between the solders 17A and 17B may be greater than the electrical resistance between the terminals at both ends of the same ground line 121 (122).

Also, the center-to-center distance W between the two solder filling holes 16A and 16B is
L×(5/12)≦W≦L×(7/12)
It is more preferable to satisfy the relationship of
In other words, in the conductor of the ground wire 121 (122), the strand located at a position rotated by 150° to 210° with respect to the strand 100 connected via the solder 17A filled in one solder filling hole 16A. 100 are preferably connected via solder 17B that fills the other solder filling hole 16B. In this case, more wire strands 100 can be electrically connected by solders 17A and 17B.

Furthermore, the center-to-center distance W between the two solder filling holes 16A and 16B is
W=L×(1/2)
is most preferred.
In other words, in the conductor of the ground wire 121 (122), the wire 100 at a position rotated 180° with respect to the wire 100 connected via the solder 17A filled in one solder filling hole 16A is It is most preferable to connect via solder 17B filled in the other solder filling hole 16B. In this case, many wires 100 that are not electrically connected via solder 17A can be electrically connected via solder 17B. That is, more strands of wire 100 than in the above case can be electrically connected via the solders 17A and 17B filled in the solder filling holes 16A and 16B, respectively.

In the embodiment, the electric resistance (conductor ^resistance ) is was measured. The diameter of the solder filling hole is preferably 11 to 13 mm, and was set to 12 mm in the embodiment.
When the distance W between the solder filling holes 16A and 16B is 80 mm (=160 mm×(1/2)), the wire 100 connected through the solder 17A in the solder filling hole 16A is , the wire 100 connected via the solder 17B is rotated by 180°. In this case, the electrical resistance between the solder 17A and the solder 17B has a value equivalent to the electrical resistance between the terminals at both ends of the same ground line 121 (122).
On the other hand, when the distance between the solder filling holes 16A and 16B is 40 mm (=160 mm×(1/4)), the wire 100 connected through the solder 17A in the solder filling hole 16A is The wire 100 connected via the solder 17B at 16B is rotated by 90°, and the electrical resistance between the solder 17A and the solder 17B is compared with the electrical resistance between the terminals at both ends of the same ground wire 121 (122). was a high value.

When the distance between the centers of the solder filling holes 16A and 16B is rotated by 90° or 270° with respect to the conductor of the ground wire, the one solder filling hole 16A is electrically connected through the solder 17A. The wires 100 that are in contact with each other and the wires that are electrically connected through the solder 17B in the other solder filling hole 16B overlap to some extent, and many wires 100 cannot be electrically connected to each other. It is considered to be for

As described above, the branch connection portion B2 (the branch connection portion of the litz wire) according to the embodiment is formed by twisting a plurality of strands 100 each having an insulating film 102 applied to the outer peripheral surface of the conductor 101, thereby forming two ground wires. A branch sleeve that mechanically connects the wires 121 and 122 (litz wire) and the two ground wires 121 and 122 by gripping and compressing the wires 121 and 122 along the longitudinal direction without removing the insulating coating 102. 15, and in a state where the two ground wires 121 and 122 are mechanically connected by the branch sleeve 15, it is formed across the two ground wires 121 and 122 so as not to penetrate in the drilling direction. The two ground lines 121 and 122 are electrically connected by filling the solder filling hole 16 with the solder 17 .

In addition, the construction method of the branch connection portion B2 (branch connection method of litz wire) includes two ground wires 121 and 122 formed by twisting together a plurality of wires 100 each having an insulating film 102 applied to the outer peripheral surface of the conductor 101. A step of mechanically connecting (litz wire) by gripping and compressing (see FIG. 6A) with a branch sleeve 15 in a state in which the (litz wire) is stretched along the longitudinal direction without removing the insulating coating 102 (see FIG. 6B). Then, a step of forming a solder filling hole 16 across the two ground wires 121 and 122 so as not to penetrate in the drilling direction (see FIG. 6C); and electrically connecting the ground lines 121, 122 of (see FIG. 6D).

According to the method of constructing the branch connection portion B2 and the branch connection portion B2 according to the embodiment, a simple method of forming the solder filling hole 16 in the portion mechanically connected by the branch sleeve 15 and filling the solder 17 can be used. , the two ground wires 121, 122 can be mechanically and electrically connected. Since the conductor 101 is exposed by forming the solder filling hole 16, it is not necessary to remove the insulating film 102 in advance. Further, since a general-purpose connection component (for example, a C-shaped cross section connector) can be applied as the branch sleeve 15, cost reduction can be achieved. Therefore, the branch connection portion B2 having stable quality electrically and mechanically can be realized easily and inexpensively.

Further, when a litz wire is applied to the ground wire EW to form the ground system 1 to be buried in the ground, if a branch connection portion is formed by bolting the terminals connected to the ground wire EW, the bolt connection There is a risk that electrolytic corrosion may occur at the terminal connection portion where the contact is made. On the other hand, since the branch connection portion B2 of the present embodiment does not require bolting, stable characteristics are maintained over a long period of time.

Also, the solder filling hole 16 is preferably formed so as to evenly straddle the contact portions of the two ground wires 121 and 122 (litz wire).
Furthermore, it is preferable that a plurality of solder filling holes 16 are provided according to the twist pitch of the ground wires 121 and 122 as described above.
As a result, most of the wire 100 can be cut or cut to expose the conductor 101 without significantly impairing the mechanical properties of the two grounding wires 121, 122, and the grounding wires 121, 122 can be securely grounded. can be made conductive.

Although the invention made by the inventor of the present invention has been specifically described above based on the embodiments, the present invention is not limited to the above embodiments, and can be changed without departing from the scope of the invention.

For example, in the embodiment, the branch sleeve 15 is a general-purpose connector with a C-shaped cross section, but the branch sleeve 15 may be another general-purpose connector such as a cylindrical sleeve with a split structure.

Further, in the embodiment, one solder filling hole 16 is formed so as to evenly straddle the contact portions of the ground wires 121 and 122 , but the solder filling hole 16 straddles the ground wires 121 and 122 . The number, size and perforation direction can be set as appropriate.

For example, as shown in FIG. 7, at least two branch sleeves 15A and 15B may be spaced apart in the longitudinal direction, and solder filling holes 16A and 16B may be provided in the respective branch sleeves 15A and 15B. As shown in FIG. 8, one branch sleeve 15 may be provided with at least two solder filling holes 16A and 16B. This increases the number of strands of the ground wires 121 and 122 that are electrically connected through the solders 17A and 17B, so that an electrically stable ground system 1 can be realized. 7 and 8 may be formed so that three or more solder filling holes are arranged. When three or more solder filling holes are provided, the distance W (mm) between the centers of the solder filling holes and the twist pitch L (mm) of the outermost layer of the two connecting ground wires 121 and 122 are determined by the above relational expression. It is not necessary to satisfy the adjacent solder filling holes, and it is preferable that at least two of the three or more solder filling holes satisfy the above relational expression.

In the example shown in FIG. 7, the branch sleeves 15A and 15B are not in electrical contact, and the current between the branch sleeves 15A and 15B is equal to the cross-sectional area of the conductor 101 that is not in contact with the solders 17A and 17B. Since the path becomes smaller, a potential difference may occur between the branch sleeves 15A and 15B. Therefore, in this case, it is preferable to electrically connect the branch sleeves 15A and 15B with an electric conductor 18 such as a braided wire. As a result, when a general-purpose connector having a C-shaped cross section is used as a branch sleeve, the branch sleeves 15A and 15B can be reliably electrically connected, and the ground wires 121 and 122 can be reliably electrically connected. A stable grounding system 1 can be realized.
Furthermore, in FIG. 8, a plurality of solder filling holes 16 are provided in one branch sleeve 15 by using a branch sleeve 15 longer in the longitudinal direction than a general-purpose connector having a C-shaped cross section. In this case, the solder 17A and the solder 17B are electrically connected by the branch sleeve 15 without connecting the electrical conductor 18 as shown in FIG. 7 to the branch sleeve.
By satisfying the aforementioned relational expression between W and L at the branch connection portion B2 shown in FIGS. Therefore, a stable grounding system 1 can be realized.

Furthermore, in the embodiment, the case where the present invention is applied to the branch connection portion B2 in the grounding system 1 has been described, but the present invention can also be applied to other branch connection portions B1, B3 to B4. For example, when the present invention is applied to the branch connection portion B1, the connection mode shown in FIG. 9 is obtained.

Further, by applying the present invention, a litz wire can be branch-connected to an existing ground wire (for example, a copper stranded wire). There is no work to cut the existing grounding wire in the middle, work to crimp the terminal on the cut part is not required, and the branch connection can be easily formed with a branch sleeve such as a C-shaped connector, improving on-site workability. do.
Further, in the embodiment, the case where the branch sleeve 15 is crimped by compression has been described, but it may be crimped by pressure using a crimping tool or a crimping machine.

It should be considered that the embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the scope of the claims rather than the above description, and is intended to include all modifications within the meaning and range of equivalents of the scope of the claims.

REFERENCE SIGNS LIST 1 grounding system 11 grounding electrode 12 grounding network 13 riser wire 14 pole connecting wire 15, 15A, 15B branch sleeve 16, 16A, 16B solder filling hole 17, 17A, 17B solder 18 electrical conductor 20 grounded body 100 strand 101 Conductor 102 Insulation film EW, 121, 122 Ground wire (litz wire)
B1 to B4 branch connection

Claims (9)

two litz wires formed by twisting a plurality of strands each having an insulating film applied to the outer peripheral surface of the conductor;
a branch sleeve that mechanically connects the two litz wires by gripping and crimping them along the longitudinal direction without removing the insulating coating,
In a state in which the two litz wires are mechanically connected by the branch sleeve, a portion connected by the branch sleeve is straddled over the two litz wires so as not to penetrate the branch sleeve in the drilling direction. a branch connecting portion of a litz wire , wherein the two litz wires are electrically connected by filling the solder filling hole with solder. 2. The branch connection portion of a litz wire according to claim 1, wherein at least two solder filling holes are provided spaced apart in the longitudinal direction. When the distance between the centers of at least two of the solder filling holes is W (mm) and the twist pitch of the outermost layer of the two litz wires is L (mm),
L×(1/3)≦W≦L×(2/3)
3. The branch connection part of the litz wire according to claim 2, which satisfies the relationship of L×(5/12)≦W≦L×(7/12)
The branch connection portion of the litz wire according to claim 3, which satisfies the relationship of 5. The litz wire branch connector according to claim 2, wherein at least two solder filling holes are provided in one branch sleeve. 5. The litz wire branch connection according to any one of claims 2 to 4, wherein two branch sleeves are arranged spaced apart in the longitudinal direction, and each of the branch sleeves is provided with the solder filling hole. Department. 7. The litz wire branch connection according to claim 6, wherein the two branch sleeves are electrically connected by an electrical conductor. The litz wire branch connector according to any one of claims 1 to 7, wherein the branch sleeve is a connector having a C-shaped cross section. Two litz wires obtained by twisting a plurality of strands of conductors each having an insulating coating on the outer peripheral surface are held by a branch sleeve in a state in which they are arranged along the longitudinal direction without removing the insulating coating. a step of mechanically connecting by crimping;
a step of forming a solder filling hole across the two litz wires in the portion connected by the branch sleeve so as not to penetrate the branch sleeve in the drilling direction;
and filling the solder filling hole with solder to electrically connect the two litz wires.

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