JPH11234885A - Straight connection - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an improved connection structure in which a connection of a shielding layer can maintain stable contact for a long period of time. SOLUTION: A cable shielding layer is formed at a straight line connecting portion formed by connecting the stripped cable conductors 2 and 2 'with a conductor connecting sleeve 1 and providing an insulating cylinder 8, a shielding layer 14 and a waterproof layer 17 on the outer periphery thereof. Ends of spacers 16, 16 'and cable sheaths 6, 6' provided with connecting portions of 5, 5 'and connecting portion shielding layer 14 in communication with the ends of the insulating tube, the outer periphery of the end of the insulating tube, and the outer periphery of the cable sheath. It is a straight connection part held in the gap formed by the above.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a connecting portion of a power cable, and more particularly to a structure of a straight connecting portion of a CV cable.

[0002]

2. Description of the Related Art An end portion of a power cable to be connected is stepped off to expose a cable conductor, and the cable conductor is inserted into the connection sleeve so as to abut against the connection sleeve and compression-connected. A connection portion is assembled by forming an insulating reinforcing layer, a shielding layer, and a waterproof layer over the outer periphery of the connecting portion.

[0003] At this time, the connection of the cable conductors is performed by a round-hex system in which a connection sleeve having a round outer shape is compressed with a hexagon die, or an ellipse-round system in which a connection sleeve having an outer shape with an elliptical shape is compressed with a round die. Is generally heavily used. As the insulating reinforcing layer, a method of inserting an insulating cylinder having a three-layer mold structure manufactured in advance in a factory into a connecting portion in order to save labor and a method of contracting an insulating tube having an enlarged diameter to the connecting portion are used. .

[0004] The shield layer of the connection portion is formed by soldering a plain woven braided wire to the cable shield layer of one power cable and winding it around the insulating cylinder or vertically attaching it to the cable shield layer of the other power cable. Often, the method of attaching is used. However, this soldering work requires skill,
In addition, since a heating source is required, the solderless method is being put to practical use especially overseas. The specific connection structure of this solderless method is a connection method in which a connection part shielding layer is laminated on the outer periphery of the cable shielding layer, and a roll spring is wound around the outer periphery of the connection part shielding layer and fixed. C processed from spring material at the end of the wire
There is a connection method in which a ring having a mold shape is welded, and the ring is attached to a cable shielding layer and fixed.

[0005] On the outer circumference of the insulating tube with the shielding layer attached, a waterproof tape wound layer as a direct waterproof layer, and a waterproof layer made of a heat-shrinkable tube layer and a normal-temperature shrinkable tube layer are provided between the sheaths of the power cables. The connection part is provided and formed.

[0006]

The basic idea of using a spring material for connection between the cable shielding layer and the connection part shielding layer is to always follow the expansion and contraction of the power cable and to provide a constant connection to the shielding layer connection part. The purpose is to maintain good contact by applying pressure. At this time, in order for the spring material to follow the expansion and contraction, the spring material needs to move freely, and this requires at least a space around the spring material to move freely.

In the above-described conventional connection method, since a waterproof layer such as a tape winding layer or a tube layer is formed directly on the outer periphery of the spring material, the movement of the spring material is restricted by these. . When the cable insulation layer and the cable shield layer of the power cable expand, the spring material restrains them from the outer periphery and fixes them, so the reaction force acts on the cable insulation layer and the cable shield layer of the power cable,
If this phenomenon is repeated for a long time, wrinkles may occur in the shielding copper tape forming the cable shielding layer of the power cable, and this copper tape may be cut. Alternatively, the cable insulating layer of the power cable may be deformed, causing poor contact with the connection portion shielding layer, generating heat, and burning the power cable.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide an improved connection structure in which a shield layer connection can maintain stable contact for a long period of time.

[0009]

SUMMARY OF THE INVENTION According to the present invention, an end portion of a power cable to be connected is stripped off, and the exposed cable conductors are inserted into a conductor connection sleeve and compression-connected. In the straight connection portion provided with a waterproof layer, the cable shielding layer and the shielding layer of the connection portion are connected to the insulating cylinder end, the outer periphery of the insulating cylinder end, and the spacer and the cable sheath end provided in communication with the outer periphery of the cable sheath. The formed gaps are formed, and a tape-shaped or tubular waterproof layer is provided on the outer periphery of these gaps.

[0010] The connection part of the shielding layer is fixed by mounting one end of a C-shaped spring connected to both ends of the plain woven braid on the cable shielding layer of one power cable,
The plain-woven braided wire may be vertically attached or wound around the outer circumference of the insulating cylinder, and the other end may be fixed by being mounted on the cable shielding layer of the other power cable.

The spacer has an inner diameter smaller than the outer circumference of the insulating cylinder, and the insertion length is set to a position sufficiently longer than the rising portion of the stress cone formed on the inner surface of the insulating cylinder. With a close shape,
The outer periphery on the cable sheath side is tapered. Then, the spacer may be pressed into the insulating cylinder and fixed integrally.

[0012]

According to the structure described above, the connection portion of the shielding layer connected by the spring is held in the gap formed by the end of the insulating tube, the end of the cable sheath, and the inner diameter of the spacer. The outer circumference of the spring is not restrained at all,
It is possible to move freely following the expansion and contraction of the power cable, and it is possible to form a good connection portion of the shielding layer for a long period of time.

Since the spacer is mounted on the outer periphery of both ends of the insulating cylinder, it is possible to freely select a material, a shape and the like in which other characteristics are emphasized irrespective of the insulating performance. For example, if a material having a high hardness and a Young's modulus larger than that of the insulating cylinder is used, it is possible to reliably maintain a gap against a large external pressure and bending of the connection portion. Since the rising portion of the stress cone, which is a cylinder, is tightened with a large force, it is possible to provide high insulation performance at the same time.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side view in which an upper half portion showing a configuration of a straight connection portion of one embodiment is a cross-sectional view. That is, in the straight connection portion of the CV cable, the ends of the respective power cables to be connected are stripped off, and the cable conductors 2 and 2 are connected.
′, Cable insulators 3, 3 ′, external semiconductive layers 4, 4 ′,
The copper tape shielding layers 5, 5 'are respectively exposed, and the mutually connected cable conductors 2, 2' are inserted into the conductor connection sleeve 1 so as to abut each other, and compressed and connected.

End processing sections 7, 7 of external semiconductive layers 4, 4 '
′ Is a method of applying a conductive paint in communication with the outer semiconductive layers 4 and 4 ′ and / or a method of winding a semiconductive tape, and performing a pencilling process on the ends of the outer semiconductive layers 4 and 4 ′. A method of winding a semiconductive tape or the like is used.

The method of connecting the cable conductors 2 and 2 ′ includes a round-hexagonal method of compressing the external round sleeve 1 with a hexagonal die,
The elliptical-circular method of compressing the external elliptical sleeve 1 with a round die, the indent compression method of press-fitting a pin from the outer periphery of the circular sleeve 1 and the compression of a female terminal having a contact built into one cable conductor and the other Any fitting method or the like in which male terminals are provided by being compressed on the cable conductor and these are fitted and connected to each other can be used.

[0017] An insulating reinforcing layer is provided on the outer periphery of the connection portion of the cable conductor thus connected. As the insulating reinforcing layer, an insulating cylinder 8 in which a central shield layer 9, an insulating layer 10, and an external semiconductive layer 11 are integrally molded is used. Both ends of the outer periphery of the insulating tube 8 are tapered to form small-diameter portions 13 and 13 '. The small diameter portions 13, 13 'may be parallel and / or loosely tapered. The difference between the large-diameter portion and the small-diameter portion of the insulating tube 8, that is, the thickness of the end portion of the insulating tube 8 forms one wall that forms a gap in the solderless connecting portion, and depends on the structure of the solderless connecting portion. From about 15 mm, a sufficient gap can be formed. As another insulating reinforcing layer, a room-temperature shrinkable tube or the like in which a shield layer 9, an insulating layer 10, and an external semiconductive layer 11 are laminated in this order from the inside can also be used.

A shield layer 14 is connected to the outer periphery of the insulation reinforcing layer formed as described above from the cable shield layer 5 of one power cable to the cable shield layer 5 'of the other power cable. This shielding layer 14 is braided in a cylindrical shape,
A plain weave braid or one obtained by welding contact plates to both ends of a plain weave braid can be used. A method for connecting both ends of the shielding layer 14 is a so-called solderless method in which the ends of the shielding layer 14 are covered and laminated on the cable shielding layers 5, 5 ', and the outer periphery thereof is pressed and fixed by roll springs 15, 15'. It is suitable.

The roll springs 15, 15 'are formed by forming a spring material such as phosphor bronze into a coil shape as shown in the perspective view of FIG.
2.0 mm and a width of 10 to 20 mm are preferable. As another connection method of the shielding layer, as shown in FIG. 5, a spring material j having a C-shaped cross section is welded to both ends of a plain woven braided wire h, and a C-shaped spring is attached to one of the cable shielding layers 5. j can be attached and fixed, and the plain weave braided wire h can be vertically attached or wound around the outer periphery of the insulating tube 8 and a C-shaped spring j can be attached and fixed to the other cable shielding layer 5 'in the same manner. .

Spacers 16, 16 'shown in FIG. 2 are attached and fixed to the outer periphery of the small-diameter portions 13, 13' of the insulating cylinder 8 so as to sandwich both ends of the shielding layer 14. The inner diameters of the spacers 16 and 16 ′ correspond to the smaller diameter portions 13 of the insulating cylinder 8.
An annular member having a substantially rhombus-shaped cross section having a large-diameter portion a to be fitted to 13 'and a small-diameter portion b to be fitted to the cable sheaths 6, 6'. By mounting the spacers 16, 16 ′ at both ends of the insulating tube 8, the end surfaces of the cable sheaths 6, 6 ′ around the spring members 15, 15 ′ and the insulating tube 8, the inner diameters of the spacers 16, 16 ′ and A gap surrounded by the cable shielding layers 5, 5 'can be reliably formed.

As another example of the spacer, it may be configured as shown in FIG. That is, the spacers 16a, 16a
′ Has a substantially rhombus-shaped cross section having a small-diameter portion b whose inner diameter portion is fitted to the small-diameter portions 13 and 13 ′ of the insulating tube 8 and the cable sheaths 6 and 6 ′, and a large-diameter portion a forming a gap therebetween. It is formed in the annular member which has.

The spacers 16, 16 'and 16a, 1
Since the material of 6a 'is mounted at a position that does not directly affect the insulation performance of the connection portion, an insulator and / or a semiconductor can be used. Further, it can be manufactured by molding a material harder than the insulating cylinder 8 or a material having a larger Young's modulus.

The spacers 16, 16 'and 16a, 1
The position at which the 6a 'is inserted into the outer periphery of the small-diameter portions 13 and 13' of the insulating tube 8 is located at the stress cone rising portion 1 of the insulating tube 8.
By making the length longer than 2, 12 ', the stress cone rising portions 12, 12' can be pressed from the outer periphery, and the insulation performance of the connection portion can be improved.

The spacers 16, 16 'and 16a, 1
6a ', the outer circumference of the insulating tube 8 is covered with a waterproof layer 17 from the cable sheath 6 of one power cable to the cable sheath 6' of the other power cable, and waterproof tapes 18, 18 'are provided at both ends. Rolled to form a straight connection. The outer periphery of the spacers 16, 16 'and 16a, 16a' is preferably tapered toward the cable sheaths 6, 6 'so as to have a tapered shape c in order to facilitate the waterproof tape winding process. .

For the waterproof layer 17, a room-temperature shrinkable material of rubber or plastic, a heat-shrinkable tube material or a tape material is used. The operation of the linear connecting portion according to the embodiment of the present invention having the above configuration will be described.

A CV cable is generally laid in an environment such as a pipeline, a tunnel, or directly buried, and is used by passing an allowable current at which an allowable value of a cable conductor temperature becomes 90 ° C. under each environment. I have. However, recently, in order to increase the transmission capacity, the allowable value of the cable conductor temperature is set to 100 ° C. or 1 ° C.
It has been considered to increase the allowable current by raising the temperature to 20 ° C.

The rise in the temperature of the cable conductors 2, 2 'necessarily leads to the rise in the temperature of the cable insulators 3, 3' and the outer semiconductive layers 4, 4 'which are the cable coating layers. The amount of thermal expansion increases. When the load is small, the current decreases and the temperature decreases, so that the cable insulators 3, 3 'and the cable outer semiconductive layers 4, 4' contract in proportion to the temperature. As described above, since the temperature of the cable conductors 2 and 2 ′ changes depending on the load, the cable insulators 3 and 3 ′ which are the cable coating layers are formed.
In addition, the cable outer semiconductive layers 4, 4 'expand and contract, and the shielding copper tape layers 5, 5' undergo thermal expansion and contraction.

A shielding layer 14 at the connection portion is laminated on the outer periphery of the shielding copper tape layers 5 and 5 ', and is fixed by being pressed against the outer periphery of both ends by roll springs 15 and 15'.

In the conventional connection structure, since a tape winding or a shrinkable tube layer is provided directly on the outer periphery of the connection portion of the shielding layer as a waterproof layer, particularly in the solderless connection system, a pressing portion such as a spring is restrained from the outer periphery. The movement following the thermal expansion and contraction of the cable coating layer is restricted. When the thermal expansion and contraction are restrained, the reaction force acts on the shielded copper tape layers 5, 5 'of the cable and the cable insulating layers 3, 3'. If this phenomenon is repeated for a long time, the shielded copper tape layers 5, 5 'are repeated. Wrinkles may occur and the copper tape may be cut. Alternatively, the cable insulators 3, 3 'and the cable outer semiconductive layers 4, 4', which are the cable coating layers, may be deformed, resulting in poor contact at the connection portions of the shielding layers, and the coating layers may be burned out by heat generated by charging current or the like. There is.

To avoid this situation, spacers 16, 16 'or 16a, 16a,
By providing 16a ', a gap can be reliably secured on the outer periphery of the shield layer connection portion, and spring materials 15, 15' such as a roll spring used for the solderless connection portion along with thermal expansion and contraction of the power cable. Is not constrained at all from the outer periphery, so that the spring members 15, 15 'can move freely following the thermal expansion and contraction.

For this reason, the solderless connection is maintained at the set pressure, and a good contact state can be maintained for a long time. Further, spacers 16, 16 'or 16 which are mounted to form a gap at the outer periphery of both ends of the insulating cylinder.
a, 16a 'have the effect of pressing the insulating tube 8 from the outer periphery of both ends of the insulating tube 8, and the insulating tube 8 and the cable insulating layers 3, 3
This force is applied to the interface of '′, and an effect of improving the insulation performance of the connection portion is also produced. In addition, at both ends of the insulating cylinder 8, the shielding layer 14 of the connection part is formed by inserting the inserted spacers 16,16.
Or 16a, 16a ', it is possible to omit the time-consuming work of winding the pressing tape, which was conventionally performed.

Since the solderless method can be used for connecting the shielding layer, the work is simpler than the conventional soldering method, and the work can be performed without skill. In this structure, a soldering method can be adopted. Here, the structure of the straight connection portion has been described. However, it is needless to say that the present invention can be similarly applied to an aerial terminal connection portion using a rubber molded product for insulation reinforcement of a cable end.

[0033]

As described above, according to the linear connecting portion of the present invention, the shielding layer connecting portion connected by the spring is held in the gap formed by the insulating cylinder end, the sheath end and the inner diameter of the spacer. Therefore, the outer periphery of the spring is not restricted, and can freely move following the expansion and contraction of the power cable, so that a good shielding layer connection can be formed for a long period of time. Further, since the spacer is mounted on the outer periphery of the insulating cylinder, it is possible to select a material, a shape, and the like in which other characteristics are emphasized regardless of the insulation performance. For example, if the material is high in hardness and has a Young's modulus larger than that of the insulating cylinder, a gap can be maintained even with a large external pressure or bending of the connection portion. Can be tightened with a large force, so that high insulation performance can also be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional side view of an upper half showing a configuration of a straight connection portion according to an embodiment;

FIG. 2 is an explanatory diagram for explaining the shape of an example of a spacer;

FIG. 3 is an explanatory diagram for explaining the shape of another spacer;

FIG. 4 is a perspective view showing an appearance of a roll spring.

FIG. 5 is a perspective view showing an example of a shielding layer.

[Description of Signs] 1 Connection sleeve 2, 2 'Cable conductor 3, 3' Cable insulator 4, 4 'Cable semiconductive layer 5, 5' Copper tape shielding layer 6, 6 'Cable sheath 7, 7' Outer conductor treatment Part 8 Insulating cylinder 9 Shield layer 10 Insulating layer 11 External semiconductive layer 12, 12 'Stress cone rising part 13, 13' Insulating cylinder small diameter part 14 Shielding layer 15, 15 'Roll spring 16, 16', 16a, 16a 'Spacer 17 Waterproof layer 18, 18 'Waterproof tape a Large-diameter part of spacer b Small-diameter part of spacer c Taper part h Plain weave element wire j C-shaped spring

Claims (9)

[Claims] 1. A connection between a cable shielding layer and a connection part shielding layer in a straight connection part formed by connecting the stripped cable conductors with a conductor connection sleeve and providing an insulating cylinder, a shielding layer, and a waterproof layer on the outer periphery thereof. A straight connection portion, wherein the portion is held in a gap formed by a spacer provided in communication with an end of the insulating cylinder, an outer periphery of the end of the insulating cylinder, and an outer periphery of the cable sheath, and a gap formed by the end of the cable sheath. 2. The straight connection part according to claim 1, wherein the connection method between the cable shielding layer and the connection part shielding layer is fixed by covering with a roll spring. 3. The straight connection portion according to claim 1, wherein a shielding layer obtained by braiding the connection portion shielding layer into a tubular shape is used. 4. The straight connection portion according to claim 1, wherein the connection method between the cable shielding layer and the connection portion shielding layer is a C-shaped spring connected to the plain woven braided wire. 5. The straight connection portion according to claim 1, wherein the inner diameter of the spacer is smaller than the outer circumference of the end of the insulating cylinder, the end surface in contact with the insulating cylinder has a shape close to the insulating cylinder, and the cable sheath side is tapered. . 6. The linear connection portion according to claim 1, wherein the spacer is provided with a large-diameter portion and a small-diameter portion of the insulating cylinder communicating with an inner diameter of the spacer. 7. The linear connection part according to claim 1, wherein the spacer is formed by molding a material using an insulator and / or a semiconductor. 8. The linear connection part according to claim 1, wherein the spacer has a Young's modulus larger than that of the insulating cylinder. 9. The insulating cylinder according to claim 1, wherein a length of a spacer mounting portion provided on the outer periphery of both ends of the insulating cylinder is longer than a stress cone rising portion of the insulating cylinder. Straight connection.