JPH08275367A - Cable connection structure - Google Patents

Abstract

PURPOSE: To connect cables with each other, without incurring the decrease of conductivity or withstand voltage by providing a cable connection structure with a seal mechanism which prevents the fused part of an insulating block from flowing into a connector terminal, and a guide member which leads bubbles generated in the insulating block to the conductor of a cable. CONSTITUTION: A seal mechanism 38 is equipped with a sealing body 40 and a seal member 42. The sealing body 40 is equipped with a circular disc 44 being fixed airtightly to the conductor 12B at an interval D apart from the end face 26 of the insulating layer 12a of a power cable 12, and a tubular part 46 being coupled airtightly to this disc 44. Therefore, in case of bridge processing of the insulating block 14, bubbles are not shut in the insulating block layer 14 or between this and the insulating layer 12A, and also the fused part of the insulating block 14 is deterred from inflow into an electrode member 16. Accordingly, cables can be connected surely with each other without incurring decrease conductivity and withstand voltage, and an electrically stable connection can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cable connecting portion structure suitable for a so-called BMJ method (block mold type connecting portion method) for forming a connecting portion between electric power cables.

[0002]

2. Description of the Related Art There is a BMJ method as a method of connecting power cables such as CV power cables to each other. According to this BMJ method, a cable in which a connector is crimped to a conductor protruding from an insulating layer by a cable end treatment has a tubular shape of an uncrosslinked (including a half-crosslinked) tube that is previously formed in a factory at a connection site. The cable is inserted into the insulating block from both ends, and the connection terminals of both cables are connected to each other at a position covered by the tubular electrode member embedded in the insulating block. In this connection state, the insulating block is subjected to a cross-linking treatment in order to integrate the insulating layer of the cables connected to each other and the insulating block, and the cross-linking treatment forms an insulator covering the connecting portion. .

By the way, during such a cross-linking process of the insulating block, since the insulating block is given fluidity,
There is a risk of flowing into the space between the connecting terminals connected to each other through the inner gap of the cylindrical electrode member. The inflow of the fluid between the connection terminals causes a decrease in conductivity between the connection terminals.

[0004]

Therefore, in order to prevent the fluid from flowing between the connection terminals, it is possible to provide a sealing mechanism at the end of the cylindrical electrode member covering the connection terminals. . However, if the inward gap of the electrode member is simply sealed by such a sealing mechanism, the electrode block is moved from the outer end portion of the insulating block to the central portion where the electrode member is provided as the crosslinking process proceeds. There is no escape route for bubbles. As a result, the bubbles having no escape route are contained as voids at the interface between the insulating layer and the insulating block. These voids cause dielectric breakdown and thus reduce the pressure resistance of the electrical connection. Then, the objective of this invention is providing the cable connection part structure which connects cables, without inviting the conductivity and pressure resistance of a cable connection part.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a pair of connections, which are fixed to conductors exposed from the end faces of the insulating layers of power cables that are connected to each other at a distance from the end faces of the insulating layers and are connected to each other. A terminal, a cylindrical electrode member arranged around the connection terminal and electrically connected thereto, and a cylindrical electrode member arranged concentrically around the electrode member and integrally connected to the insulating layer of the cable by a cross-linking treatment. At the cable connection part including the tubular insulation block, the sealing mechanism that prevents the molten portion of the insulation block from flowing toward the connection terminal during the cross-linking process of the insulation block In addition to being provided between the end of the insulating layer and the connection terminal, the air bubbles generated in the insulating block during the cross-linking process are provided toward the conductor of the cable. Characterized in that a guide portion for.

[0006]

In the present invention, the bubbles generated from the insulating block or the interface between the insulating block and the insulating layer are moved from the outer end portion of the insulating block toward the central portion where the electrode member is provided as the crosslinking treatment progresses, Escape between the conductor wires through the guide part of the seal mechanism. On the other hand, the fused part of the insulating block is
The conductor does not flow between the closely-attached wires, and the seal mechanism reliably prevents the inflow toward the connection terminal.

[0007]

The present invention will be described in detail below with reference to the illustrated embodiments. FIG. 1 is a longitudinal section showing a cable connecting portion according to the present invention. The cable connecting portion 10 according to the present invention includes a pair of power cables 12, 1 such as a CV cable.
The insulating block 14 which is applied to the connection of 2 and has a tubular shape as a whole is used. The insulating block 14 is made of, for example, an uncrosslinked or semi-crosslinked insulating material obtained by mixing a polyethylene material with a crosslinking agent similar to the insulating layer 12A of the power cable. The insulating block 14 is tapered toward both ends thereof, and a cylindrical electrode member 16 is concentrically embedded in the inner hole 14A of the insulating block 14.

Inside the electrode member 16, a tubular hook portion 20 is provided which is engaged with one end of each of a pair of tubular contacts 18 similar to the conventional one. The tubular contact 18 includes a large number of contact pieces 22 and an annular coil spring 24 that connects the contact pieces 22 in a tubular shape. The cylindrical contact 18 is
Each end of the contact piece 22 is engaged with the hook portion 20 formed on the inner circumference of the electrode member 16 and incorporated in the electrode member 16.

Power cables 12, 12 connected to each other
Has an insulating layer 12A made of cross-linked polyethylene and an end face 26 of the insulating layer 12A, and a conductor 12B sequentially exposed at the ends to be connected. The exposed conductor 12B is spaced apart from the end face 26 by a connection terminal 28. , 30 are fixed by crimping. Connection terminals 28, 30
Are connected to each other at the inner position of the electrode member 16 via the fitting portions 32 and 34 forming a male and female pair. At this connection position, each of the connection terminals 28, 30 is locked to the other end of the cylindrical contactor 18 by a protruding portion 36 formed outwardly in the radial direction.

The electrode member 16 is connected to the connection terminals 28 and 30 via the cylindrical contact 18 so that the outside of the connection terminals 28 and 30 is surrounded by a smooth surface having the same electric potential. As a result, the electrode member 16 acts to prevent partial concentration of the electric field and enhance the pressure resistance.

Connection terminals 28, 3 of both cables 12, 12
After connecting 0 inside the electrode member 16, the insulating block 1
4 is subjected to a cross-linking treatment and is integrally bonded to the insulating layer 12A of the cable 12, but for preventing the molten portion of the insulating block 14 which is softened at this time from flowing toward the connection terminals 28 and 30. The seal mechanism 38 is provided at both ends of the electrode member 16.

FIG. 2 is an enlarged partial sectional view of one sealing mechanism 38 which is a part of the cable connecting portion according to the present invention. The sealing mechanism 38 includes a sealing body 40 that is inserted into the conductor 12B of the power cable 12 before attaching the connection terminals 28 and 30 to the conductor 12B, and an inner side of the electrode member 16 in cooperation with the sealing body 40. And an annular seal member 42 for sealing.

In the illustrated example, the sealing body 40 is an annular disc portion 44 that is airtightly fixed to the conductor 12B at a distance D from the end surface 26 of the insulating layer 12A of the power cable 12, and the disc portion 44. And a tubular portion 46 that is airtightly coupled to. A male screw groove 48 is formed on the outer peripheral surface of the disc portion 44, and a female screw groove 50 that is airtightly screwed into the male screw groove 48 is formed on the inner peripheral surface of the base end of the tubular portion 46. Prior to the screwing of the screw grooves 48 and 50, the connection terminals 28 and 30 are fixed to the conductor 12B, and the disk portion 44 is formed into the insulating layer 1.
It is fixed to the conductor 12B in an airtight manner with a uniform distance D from the end face 26 of 2A in the circumferential direction. This distance D is 1 mm to 3
mm is preferred. Subsequently, a seal tape 5 for enhancing airtightness is provided between the connection terminals 28, 30 and the disc portion 44.
It is desirable to wind two.

After winding the sealing tape 52, the disc portion 44
The female thread groove 50 of the cylindrical portion 46 is airtightly screwed into the male thread groove 48, and the sealing body 40 is assembled. In the state where the sealing body 40 is assembled, the cable 12 is connected so that both connection terminals 28 and 30 of the power cables 12 and 12 are connected inside the electrode member 16 as shown in FIG.
Ends of the insulating block 14 are inserted into the inner hole 14A from both ends of the insulating block 14.

By inserting the power cable 12 into the inner hole 14A, the tubular portion 46 of the sealing body 40 is inserted into the electrode member 16 from both ends of the electrode member 16. A concave groove 54 is formed on the inner peripheral surface of each end of the electrode member 16, and the seal member 42 housed in the concave groove 54 has a cylindrical portion 46.
Close to the outer peripheral surface of. As a result, the sealing body 40 and the sealing member 42 that are spaced from the end surface 26 of the insulating layer 12A by the distance D.
Thereby, both ends of the electrode member 16 are reliably sealed.

In the cable connecting portion 10 according to the present invention, when the insulating block 14 is subjected to the crosslinking treatment, the insulating block 14 is provided with the electrode member 16 from the thin outer end portion thereof along with the progress of the crosslinking treatment. When melted sequentially toward the part,
Bubbles generated from the insulating block 14 or the interface between the insulating block 14 and the insulating layer 12A are moved toward the central portion where the electrode member 16 is provided due to the melting. Since the end portion of the electrode member 16 is sealed by the sealing mechanism 38, this bubble uses the gap D between the sealing mechanism 38 and the end surface 26 of the insulating layer 12A as the guide portion 56 and between the strands of the conductor 12B. Will be guided to.

Therefore, air bubbles are not trapped between the insulating block 14 and the insulating layer 12A as in the conventional case, and the dielectric breakdown due to the voids caused by the entrapment of the bubbles is prevented and the withstand voltage is increased. You can improve your sex.

Further, since the melted portion of the insulating block 14 is prevented from flowing into the electrode member 16 by the sealing mechanism 38, the connection terminals 28, 30 in the electrode member 16 are prevented.
It does not flow into the connection part and is blocked without penetrating between the strands of the conductor 12B. As a result, it is possible to prevent a decrease in conductivity due to the molten portion of the insulating block 14 entering the connecting portion.

Therefore, the cable connecting portion 10 according to the present invention.
According to this, the cables can be reliably connected to each other without lowering the conductivity and the pressure resistance of the cable connection portion, and an electrically stable connection portion can be obtained.

In the illustrated example, the sealing body is composed of the disc portion 44 and the tubular portion 46, but the sealing body is not limited to this and various types of sealing bodies can be applied. Further, in order to form the guide portion 56 for guiding the bubbles between the conductor wires,
An example in which the sealing body 40 is arranged at equal intervals D in the circumferential direction from the end surface 26 of the cable insulating layer has been shown, but instead of this, the sealing body 40 is arranged in contact with the end surface 26 of the insulating layer. Then
A guide groove or the like can be formed in either one of the sealing body 40 and the insulating layer to form a guide portion. However, as shown in the figure, it is extremely advantageous to use the gap D between the sealing body 40 and the end surface 26 of the cable insulating layer as a guide portion in terms of simplification of the manufacturing process.

[0021]

As described above, in the cable connection structure according to the present invention, the bubbles generated from the insulating block or the interface between the insulating block and the insulating layer escape between the conductor wires through the guide portion of the sealing mechanism. On the other hand, the melted portion of the insulating block does not flow between the wires of the conductor that are in close contact with each other, and the sealing mechanism prevents the inflow toward the connecting terminal. Does not remain as a void and the molten portion of the insulating block does not flow between the connection terminals. Therefore, according to the present invention, the cables can be reliably connected to each other without lowering the conductivity and the pressure resistance of the cable connecting portion.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing the structure of a cable connecting portion according to the present invention.

FIG. 2 is a partial cross-sectional view showing an enlarged part of the cable connecting portion according to the present invention.

[Explanation of symbols]

 10 Cable Connection Part 12 Power Cable 12A Insulation Layer 12B Conductor 14 Insulation Block 16 Electrode Member 26 End Face 28, 30 Connection Terminal 38 Sealing Mechanism 56 Guide Part

Claims (2)

[Claims] 1. A pair of connection terminals, which are fixed to a conductor exposed from an end surface of an insulating layer of an electric power cable connected to each other at a distance from the end surface and are connected to each other, and the connection connected to each other. A cylindrical electrode member arranged around the terminal and electrically connected to the connection terminal, and a cylindrical electrode member arranged concentrically around the electrode member and integrally coupled with the insulating layer by a cross-linking treatment. An insulating block is provided between the end surface of the insulating layer and the connection terminal, and a molten portion of the insulating block is provided between the conductor and the corresponding end of the electrode member when the insulating block is crosslinked. A sealing mechanism that prevents the inflow toward the connection terminal, and a bubble that is provided in association with the sealing mechanism and that is generated in the insulating block during a cross-linking process is in contact with the end surface of the insulating layer. Cable connection structure including a guide portion for guiding towards the conductor between the terminals. 2. The cable according to claim 1, wherein each of the sealing mechanisms is arranged at a distance from an end surface of the insulating layer of the power cable, and the distance constitutes the guide portion. Connection structure.