JPH0134509Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a cable insulating connection portion that insulates a cable outer conductor at the cable connection portion.

In order to facilitate the discovery of cable fault sections and reduce cable sheath current loss, the cable outer conductor is sometimes insulated and connected at the cable connection. Figure 1 shows a known insulated connection of a rubber/plastic cable. It shows.

In Figure 1, J' is a cable connector;
A cable end receiving hole 11' is provided in the insulator 1', and a metal jacket 12' is integrated with the insulator 1'. 2'
is the cable end inserted into the receiving hole 11',
3' is a rubber cone inserted into the cable terminal 2' and has a bellmouth shielding layer 31', which is in contact with the cable outer semiconductive layer 21'. 4' is a cable protection metal tube, which has an insulating tube 5' in the middle, and a cable connector.
A connection is made between J' and cable sheath 22'.
6' is a rubber cone push pipe (usually made of fiber-reinforced plastic), 61' is a spring,
The compressive stress of the spring 61' compresses the rubber cone 3'. 7' is a bond line,
The cable outer metal shielding layer 23' and the cable protection metal pipe rear half 42' are bonded. 8' is a lead wire, which is connected to the latter half 42' of the cable protection metal tube.

In FIG. 1, when the insulating tube 5' becomes electrically conductive, the outer metal shielding layer end 23' of the cable
As shown by A', electrical continuity is established through the bond wire 7' → the latter half of the cable protection metal tube 42' → the conductive insulating tube 5' → the first half of the cable protection metal tube 41' to the metal jacket 12' of the cable connector J'. This leads to loss of insulation connection performance. Normally, the above-mentioned insulating tube 5' is covered with an insulating cover, but because the insulating tube has a protruding shape, its watertightness is not very reliable, and it is not suitable for places where flooding is difficult to avoid, such as inside a manhole. In this case, the above-mentioned loss of insulation connection performance cannot be avoided.

The cable connection unit according to the present invention has a structure that eliminates the above-mentioned disadvantages and can stably maintain insulation connection performance, and the cable terminal is inserted into the cable terminal receiving hole provided in the insulator of the cable connector, The cable end receiving hole is filled with a rubber cone having a bell mouth shielding layer and at least the upper end of the shielding layer is covered with an insulating layer, and the cable connector and the cable sheath are connected with a cable protection metal tube. This structure is characterized in that a lead wire is connected to the external metal shielding layer, the lead wire is drawn out from the cable protection metal tube, and the space between them is insulated.

The present invention will be explained below with reference to the drawings.

In Figure 2, J is a cable connector;
A metal jacket 13 is integrally provided on an insulator 1 having a cable terminal receiving hole 11 and a conductor connection fitting 12. 2 is the end of the rubber/plastic cable, which is inserted into the cable end receiving hole 11 of the cable connector J.
and connect the cable conductor 21 to the cable connector J.
It is connected to the conductor connection fitting 12 of. Reference numeral 3 denotes a rubber cone for relieving electrical stress, which is inserted into the cable terminal in advance and housed in the cable terminal receiving hole 11. At least the upper end of the bellmouth shielding layer 31 of the rubber cone 3 is coated with an insulating layer 4 (usually made of the same material as the rubber cone), and in the case shown in FIG. An insulating layer 4 is coated over the entire length. The lower end of the bellmouth shielding layer 31 is brought into contact on the outer semiconductive shielding layer 22 of the cable termination.
5 is a cable protection metal tube, and the front metal tube 51
and a rear metal tube 52, and these metal tubes connect the cable connector J and the cable sheath 23. Reference numeral 6 denotes a rubber cone holding pipe (made of metal, glass fiber reinforced plastic), which has a shaft 61, into which a spring 62 and a sliding ring 63 are inserted, and the sliding ring 6
3 is locked to a stepped portion 510 on the inner surface of the front metal tube. Thus, the spring 62 is compressed, and the rubber cone 3 is compressed by this stress. Reference numeral 7 denotes an insulated wire for a lead connected to the end 24 of the external metal shielding layer of the cable, and is drawn out from the rear metal tube 52 described above. Therefore, the insulation coating 70 of the lead wire 7 is between the lead wire 7 and the cable protection metal tube 5.
ensure reliable insulation. Reference numeral 8 denotes an insulating layer, such as a heat-shrinkable plastic tube, coated on the outer shielding layer of the cable terminal, and is used to prevent any damage between the outer shielding layer and the above-mentioned shaft rod, spring, and sliding ring (all made of metal). This is to prevent contact and can be omitted.

In order to improve the watertightness of the lead wire drawing section, a waterproof cover 70 can be provided as shown in FIG. 4.

In Figure 2, the outer metal shielding layer 2 of the cable
The parts that are electrically connected to the lead wire 7 are the conductor 71 of the lead wire 7, the cable outer semiconductive layer 22, and the rubber cone bell mouth shielding layer 31.
1 and the cable protection metal tube 5 are insulated by the insulation coating 70 of the lead wire 7, and the cable outer semiconductive layer 22 and the cable protection metal tube 5 are insulated by an insulating space. Since the mouse shielding layer 31 and the cable protection metal tube 5 (the metal jacket of the cable connector) are insulated by the insulation coating, the outer conductor of the cable, the cable protection metal tube, and the cable connector metal jacket are insulated. Can be insulated reliably.

The cable connection unit according to the present invention can be used for cross-bonding of the outer conductor of a cable line, detection of a faulty section of a cable, etc., and FIG. 5 shows an example of the latter.

In Fig. 5, J,... are the cable branch connection parts according to the present invention, 13,... are the metal jackets of the connection parts,
W,... are cables, 24,... are cable external shielding layers, i,... are insulation parts, 7,... are lead wires, T,...
is a current transformer, and the output side of the current transformer is led to a central monitoring room, where the fault section of the cable is detected.

The cable connection part according to the present invention has the above-mentioned configuration, and the upper end of the bell mouth shielding layer of the rubber cone is connected to the cable terminal receiving hole at ground potential (the hole in the metal jacket of the connector, the end of the cable protection metal tube). In addition to insulating the cable with an insulating coating, the lead wire of the cable external shielding layer is also insulated from the cable protection metal tube at the same earth potential as above, so insulated connections can be made without providing an insulating tube on the cable protection metal tube. It is possible to eliminate loss of insulation connection performance due to flooding of the cylinder. In addition, the insulating tube can be omitted and a metal one can be used for the rubber cone push pipe.
It is also advantageous in reducing costs.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing a conventional cable connection part.
Fig. 2 is an explanatory diagram showing the cable connection part according to the present invention, Fig. 3 is an explanatory diagram showing the rubber cone used in the present invention, and Fig. 4 is an explanatory diagram showing the lead wire extraction part of the cable external metal shielding layer in the present invention. Explanatory diagram,
FIG. 5 is an explanatory diagram showing a cable line using the cable connection part of the present invention. In the figure, J is a cable connector, 1 is an insulator, 11 is a cable terminal receiving hole, 2 is a cable terminal, 3 is a rubber cone, 31 is a bell mouth shielding layer,
4 is an insulating layer, 5 is a cable protection metal tube, and 7 is a lead wire.

Claims (1)

[Scope of utility model registration request] Insert the cable terminal into the cable terminal receiving hole provided in the insulator of the cable connector, and fill the cable terminal receiving hole with a rubber cone having a bell mouth shielding layer and having at least the upper end of the shielding layer covered with an insulating layer. The cable connector and the cable sheath are connected by a cable protection metal tube, the lead wire is connected to the cable external metal shielding layer, the lead wire is drawn out from the cable protection metal tube, and the space between them is insulated. A cable connection section featuring: