JPH11266521A - Power cable joint and its forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the diametrical expansion rate of an insulation unit, and furthermore, reduce the relief allowance of the expanded insulation unit for reducing the dimensions of a joint itself. SOLUTION: A joint has a conductor connection part which is formed by retaining male terminals 2A and 2B, with a female terminal 3 and a diameter expansion type insulation unit 1 covering the conductor connection part. It is preferable to use tulip contacts or multibands in the conductor connection part. Since the cable conductor connection is of insertion type conductor connection part composed of the male and female terminals 2A, 2B and 3, the relief for the insulation unit 1 on a cable core can be dispensed with.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power cable connecting portion using an insulator unit having an enlarged diameter and a method for forming the same.

[0002]

2. Description of the Related Art FIG. 6 is a longitudinal sectional view showing an example of a plug-in connection portion of a plastic power cable. Generally, plastic power cables have conductors in order from the center.
21, an inner semiconductive layer, an insulator 22, such as cross-linked polyethylene, an outer semiconductive layer 23, and a metal shielding layer. The outermost part is provided with a plastic sheath such as polyethylene or vinyl chloride. At the end of each cable, the conductor 21, the insulator 22, and the outer semiconductive layer 23 are exposed in a stepwise manner, and the conductor 21 is compressed by a sleeve or the like to form a conductor connection portion 24.

[0005] An insulator unit 25 is fitted around the outer periphery of the conductor connection portion 24. This is because the outer semiconductive layer 26 on the outer peripheral side, the inner semiconductive layer 27 on the inner peripheral side, and the insulating rubber part
28 is integrally formed. Since the inner diameter of the insulator unit 25 is smaller than the outer diameter of the cable insulator 22, a jig for expanding the diameter (not shown) is required for mounting on the cable insulator.
Is used. First, the diameter increasing jig is inserted into the inner diameter portion of the insulator unit 25 to expand the diameter of the insulator unit 25 in the diameter direction.
Next, the insulator unit 25 whose diameter has been increased is fitted into one of the cables and once escaped, and the conductor 21 is connected. Then, the expanded insulator unit 25 is positioned outside the conductor connection portion 24, and the jig for diameter expansion is pulled out, so that the insulating unit 25 is brought into close contact with the cable insulator by the tightening force due to the contraction of the insulator unit 25. Installing.

[0004] As described above, the insulator unit has the effect of achieving the close contact at the interface with the cable insulator only by the tightening force due to the contraction of itself. It is known that the tightening force decreases as the diameter expansion ratio increases because the tightening force of the insulator unit decreases, and it is necessary to suppress the diameter expansion ratio as much as possible to secure the reliability of the connection portion. .

[0005]

However, in order to release the expanded insulator unit onto the plastic sheath, it is necessary to increase the inner diameter of the insulator unit beyond the outer diameter of the sheath. Normally, it is necessary to increase the diameter of the cable in consideration of the bend of the cable. Further, in order to suppress the diameter expansion rate as much as possible, it is necessary to ensure the linearity of the cable and to release the expanded insulator unit onto the cable core (from the conductor to the external semiconductive layer). To form this relief, the plastic sheath (not shown) must be stripped. The portion where the plastic sheath has been stripped requires a separate restoration of the sheath, and the total length of the connecting portion is long including the stripped portion of the plastic sheath. However, generally, plastic power cables for power transmission are laid in underground conduits, and connection work needs to be performed in a limited space underground, and it is desirable that the total length of the connection portion be as short as possible.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a power cable connecting portion and a method of forming the power cable connecting portion capable of suppressing the diameter expansion rate of the insulator unit, shortening the escape allowance of the expanded insulator unit and shortening the connection portion itself. Is to provide.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is characterized by a conductor connecting portion connected by engagement of a female terminal and a male terminal, and an expanded portion covering the conductor connecting portion. At a power cable connection comprising a radial insulator unit.

Here, it is preferable to use a tulip contact or a multi-band for the conductor connection portion. Further, it is desirable to provide a shrink-back mechanism for connecting between the male terminal and the cable insulating layer or between the female terminal and the cable insulating layer.

On the other hand, the method of the present invention, which is most suitable for forming the above-mentioned connection portion, comprises a step of arranging an insulator unit having a diameter increased by a diameter-expanding pipe at a predetermined position; A step of inserting a cable into the cable and connecting the conductor of the cable by engaging the male terminal and the female terminal, and a step of removing the expanded pipe and covering the conductor connection portion with an insulator unit. And

[0010]

Embodiments of the present invention will be described below. FIG. 1 is an explanatory diagram of a method of forming a connecting portion of the present invention before connecting a conductor, and FIG. 2 is an explanatory diagram of a method of forming a connecting portion of the present invention showing a condition after connecting a conductor. The connecting portion of the present invention uses the expanded-diameter insulator unit 1 and forms a connection portion without escape of the insulator unit 1 by engaging the conductors by engaging the male and female terminals 2A, 2B and 3.

First, the inner diameter is expanded by inserting a diameter increasing jig 4 into the inner diameter portion of the insulator unit 1 similar to that described with reference to FIG. As the diameter-enlargement jig 4, for example, a jig that can be divided into two in the axial direction and further each can be divided into two in the radial direction is used. The extent to which the diameter is increased is such that the inner diameter of the insulator unit 1 is slightly larger than the outer diameter of the cable core (from the conductor to the outer semiconductive layer).

The cable to be connected has, for example, a conductor 5, an inner semiconductive layer, an insulator such as cross-linked polyethylene 6, an outer semiconductive layer, and a metal shielding layer in order from the center. It has a plastic sheath. The end of each cable to be connected exposes the outer semiconductive layer, insulator 6 and conductor 5 stepwise. At this time,
The length at which the sheath is stripped off at each cable end may be slightly longer than half of the combined length of the insulator unit 1 and the diameter increasing jig 4. Conventionally, the insulator unit 1 whose diameter has been expanded
The length of stripping the sheath had to be longer than that of the insulator unit in order to allow the cable to escape onto one of the cable cores. In the method of the present invention, as described later, it is not necessary to release the insulator unit whose diameter has been increased onto the cable core, so that the stripping length of the sheath can be reduced.

The insulator unit 1 whose diameter has been increased as described above is set at the final position of the cable connection portion. Then, without connecting the insulator unit 1 in the axial direction, a cable end is inserted thereinto to connect the conductor. Male and female terminals 2A, 2B, 3 are used for this conductor connection. For example, as shown in FIG. 1, male terminals 2A and 2B having a bulged tip are fixed to the conductor 5 of each cable by compression or the like, and the female terminal 3 is inserted into one male terminal 2A to engage the cable. Let it match.
The female terminal 3 is a cylindrical one with both ends opened, and the male terminals 2A, 2
It has an inner peripheral shape corresponding to the tip shape of B. Then, each cable is inserted from both sides of the insulator unit 1 whose diameter has been increased, and the male terminal 2B of the other cable is inserted into and engaged with the female terminal 3 already attached to one of the cable ends. (FIG. 2). In FIGS. 1 and 2, the case where the male terminal is inserted from both sides of the female terminal has been described as an example. However, the female terminal is fixed to one conductor in advance by compression or the like, and the male terminal is compressed to the other conductor by compression or the like. Alternatively, both male and female terminals may be engaged.

Here, a tulip contact or a multi-band can be used to connect both cable conductors. FIG. 3 is a sectional view showing an example of a tulip contact. The male terminal 2A is attached to the tip of the cable conductor 5, and the male terminal engaging projection 7 is connected to the tulip contact 8
The electrical connection as well as the mechanical connection is made by fitting the cable. On the other hand, FIG. 4 is a cross-sectional view of an example in which connection is made using multiband. In this case, the outer protrusion 9 of the male terminal 2A fixed to the conductor 5 is connected to the inner protrusion 10 of the cable insertion portion.
The electrical connection is performed by the multiband 11 provided on the outer periphery of the tip of the male terminal.

Furthermore, it is preferable to take measures against shrink-back at this connection portion. FIG. 5 shows a cable insulator 6
FIG. 6 is a cross-sectional view showing a state where the retention jig 12 is mounted between the male terminal 2A and the male terminal 2A. Notch groove 13 on the outer peripheral surface of the exposed insulator end
And a notch groove 14 is also formed on the outer periphery of the male terminal. Then, the insulator 6 and the male terminal 2A are connected by fitting the tubular retaining jig 12 having the inner peripheral projections at both ends into the cutout grooves 13 and 14. As a result, the phenomenon that the cable insulator separates from the conductor connection portion can be suppressed.
27 can be minimized, and the dimensions of the insulator unit and the cable connection part can be reduced.

Although FIG. 5 shows a drawing jig for connecting the insulator and the male terminal, a drawing jig for connecting the insulator to the female terminal may be used instead (not shown). . That is, instead of the cutout groove on the outer periphery of the male terminal, a cutout groove may be formed on the outer periphery of the female terminal, and a holding jig similar to the holding jig of FIG. 5 may be fitted into both notch grooves.

[0017]

As described above, according to the connecting portion and the forming method of the present invention, it is not necessary to release the insulator unit onto the cable core in the forming process, so that the release allowance formed by stripping the sheath can be reduced. The length of the connecting portion can be reduced.

Further, since the diameter of the insulator unit does not need to be increased beyond the outer diameter of the cable sheath, the diameter expansion ratio can be reduced, and a connection portion having a high interface performance between the insulator unit and the cable insulator can be formed. Can be. In particular, if the diameter of the insulator unit is small, the insulator unit can be shipped in a state where the diameter of the insulator unit is expanded, and the work of expanding the diameter at the connection part forming site can be omitted.

Further, by providing a shrink-back countermeasure mechanism, the phenomenon that the cable insulator separates from the conductor connection portion can be suppressed, so that the dimensions of the insulator unit and the cable connection portion can be reduced.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a method for forming a connecting portion of the present invention before connecting a conductor.

FIG. 2 is an explanatory diagram of a method of forming a connection portion of the present invention after conductor connection.

FIG. 3 is a sectional view of a conductor connecting portion using a tulip contact.

FIG. 4 is a cross-sectional view of a conductor connecting portion using a multi-band.

FIG. 5 is an explanatory view showing a shrinkback countermeasure mechanism.

FIG. 6 is a partial sectional view of a pluggable power cable connection.

[Explanation of symbols]

1,25 Insulator unit 2A, 2B Male terminal 3 Female terminal 4 Jig for diameter expansion 5 Conductor 6,22 Insulator 7 Outer protrusion 8 Tulip contact 9 Outer protrusion 10 Inner protrusion 11 Multiband 12
Retention jig 13,14 Notch groove 23 External semiconductive layer 24 Conductor connection
26 Outer semiconductive layer 27 Inner semiconductive layer 28 Insulation rubber

Claims (4)

[Claims] 1. A power cable connection portion comprising: a conductor connection portion connected by engagement of a female terminal and a male terminal; and a diameter-insulating unit covering the conductor connection portion. 2. A conductor connecting part comprising a tulip contact or a multi-band.
Power cable connection as described. 3. The power cable connecting part according to claim 1, further comprising a shrink back mechanism for connecting between the male terminal and the cable insulating layer or between the female terminal and the cable insulating layer. 4. A step of arranging an insulator unit having a diameter increased by a diameter-expanding pipe at a predetermined position, inserting a cable inside the insulator unit without moving the insulator unit, and engaging a male terminal and a female terminal. A method for forming a power cable connection portion, comprising: a step of connecting the conductors of the above; and a step of removing the expanded pipe and covering the conductor connection portion with an insulator unit.