JPH04210721A - Connecting method for rubber/plastic power cable - Google Patents

Abstract

PURPOSE:To accurately position a high voltage shielding electrode by forming the inner peripheral wall of an insulation reinforcing cylinder in a tapered state increased in diameter from its center to both ends, disposing the cylinder on a cable connector, and then inserting diameter matching spaces coincident with the inner wall of the cylinder into both ends of the cylinder. CONSTITUTION:The inner peripheral wall of an insulation reinforcing cylinder 3 is formed in a tapered surface from both ends to the center in a diameter reducing manner, and profiles of spacers 2a, 2b are coincident with the air gap shape of the wall. Thus, the inserting limits of the spacers 2a, 2b are set to the exposed edge of a high voltage shielding electrode 4 of the cylinder 3. When the inserting ends 21a, 21b of the spacers are brought into contact with a conductor cover 5, the electrode 4 is effectively superposed on the cover 5 without deviation. Accordingly, the cylinder 3 is movably provided on a cable connector, and even if the position of the electrode 4 is not visually observed, it can be positioned on the cover 5. Since the tapered surfaces of the outer surfaces of the spacers 2a, 2b are so inserted as to be opposed, its assembled state is scarcely collapsed.

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for connecting rubber-plastic power cables with molded connections. [0002]

[Conventional techniques] Methods for forming intermediate joints of rubber/plastic power cables such as ICV cables include a method in which a polyethylene tape containing a crosslinking agent is wound around the cable joint and heat molded; A common method is to attach a mold, fill the mold with polyethylene compound, and crosslink it by heating from the outside to form an insulation reinforcement. However, these methods require a lot of time, considerable experience, and skill, and the tape winding method requires transporting a tape winding machine and the compound injection method requires transporting a heavy extruder to the work site. It's hard to say it's practical. [0003] The present applicant has previously proposed a connection part that solves the above problems, saves equipment and manpower, and is easy to form, in Japanese Patent Application Laid-Open No. 2-51306. FIG. 7 shows a sectional view of the connection part of the conventional example, in which the conductors 10a and 10b of the CV cables la and lb to be connected are connected to the conductor connection tube 11.
A conductor cover 50 is placed thereon, and half diameter matching spacers 20a and 20b made of polyethylene material to which a crosslinking agent has been added are placed on the end insulators of the cables la and lb. Then, the insulation reinforcing tube 30 with a built-in high voltage shield electrode 40 inserted into the cable in advance,
Cables la and lb are moved onto the connecting portion, and finally the semiconductive tape 60 is wound around the insulation reinforcing tube 30, and then,
The connecting cylinder is formed by heating within the mold. [0004] In this connection method, the connecting parts are made into units and assembled and molded on site, so construction time can be shortened, large-scale equipment is not required, and construction can be easily performed even by non-skilled workers. It has the advantage of being [0005] [Problem to be Solved by the Invention] By the way, in such a connection part, the high voltage shield electrode 40 buried in the insulation reinforcing tube 30 is used for adjusting the diameter of the connection part of the conductors 10a and 10b. It is desirable that the conductor cover 50 is aligned and in contact with the provided conductor cover 50 as accurately as possible. That is, if the shield electrode 40 and the conductor cover 50 are in a disconnected state at the connection part,
This is because there is a high possibility that the electrical characteristics of the connection portion will be adversely affected. [0006] However, in the above conventional method, it was difficult to position the shield electrode 40. That is, the shield electrode 40 is attached to the inner peripheral wall of the insulation reinforcing tube 30 with the conductor cover 5.
Although the contact surface with 0 is exposed, the other part is buried in the insulation reinforcing tube 30, so the insulation reinforcing tube 30, which has been inserted into one cable in advance, is inserted into the cable 1a.
This is because the position of the high voltage shield electrode 40 cannot be visually observed when moving it to a predetermined location on the lb connection portion. Therefore, in order to accurately position the shield electrode 40 and the conductor cover 50, precisely measure the dimension from the open end of the insulation reinforcing tube 30 to the exposed edge of the shield electrode 40, and place a mark that matches the measured value on the cable surface. This required extremely troublesome work, such as adding the Moreover, even if such measurements were performed, it was not possible to reliably confirm whether the shield electrode 40 was located at a predetermined location. [0007]Furthermore, in the conventional method, the insulation reinforcing tube 30 is moved after the halved diameter adjusting spacer 20 is placed on the connecting portion of the cables la and lb. Therefore, although the surface of the spacer 20 and the inner circumferential wall of the insulation reinforcing tube 30 are parallel to the cable surface, on the diameter matching spacer 20 which is not fixed on the cable circumference,
Since the insulating reinforcing body 30 is moved by sliding, there is also a problem that the assembled state of the diameter adjusting spacer 20 and the conductor cover 50 before molding may change due to the movement of the insulating reinforcing body 30. [0008]

OBJECTS OF THE INVENTION An object of the present invention is to provide a cable connection method that allows accurate positioning of a high-voltage shield electrode and reliable assembly of a connection portion before molding. [0009]

[Means for Solving the Problems] The rubber/plastic power cable connection method of the present invention has a high-voltage shield electrode at the center on the conductor connection portion of the rubber/plastic power cable, and the inner diameter of the cable extends from both ends to the center. An insulation reinforcing cylinder having a tapered inner circumferential wall with a smaller diameter toward the end is placed, and then a diameter matching spacer matching the shape of the gap is inserted into the gap between the cable and the inner circumferential wall of the insulation reinforcing cylinder, and then heated. It is characterized by molding. [0010]

[Operation] The inner circumferential wall of the insulation reinforcing tube is made into a tapered shape that increases in diameter from the center to both ends, and after first placing the insulation reinforcing tube on the cable connection part, the diameter matching the inner circumferential wall of the insulation reinforcing tube is When the mating spacer is inserted from both ends of the insulation reinforcing tube, the conductor cover functions as a spacer insertion stopper, so that the high voltage shield electrode is naturally located on the conductor cover. In addition, the contact surface between the insulation reinforcing tube and the diameter adjusting spacer is inclined with respect to the longitudinal direction of the cable, and the spacer with a tapered cross section is inserted later, so the assembled state of the cable connection part before molding becomes less likely to collapse. [00111] [Embodiment] An embodiment of the present invention will be described in detail below based on the drawings. [00121] FIG. 1 is a cross-sectional view of a cable connection part in which the rubber/plastic power cable connection method according to the present invention is implemented. la, lb are rubber/plastic power cables, such as C ■ cables, and cables la, lb
The conductors 10a and 10b are exposed at the ends thereof, and are compressed and connected by a conductor connecting tube 11 made of steel or the like. Further, the exposed conductors 10a, 10b and the conductor connecting tube 11 are covered with a conductor cover 5 made of metal (conductive rubber or the like may be used). [0013] An insulating reinforcing tube 3 having a built-in metal high-voltage shield electrode 4 as shown in the perspective view of FIG. 2 is disposed on the connecting portion of the cables la and lb. Insulation reinforcement tube 3
is formed into a spindle shape from rubber/plastic material added with a crosslinking agent or crosslinked rubber/plastic, and has a cylindrical center part and cable insertion holes 3a at both left and right ends.
, 3b are provided. The high-voltage shield electrode 4 has a ring-shaped flange portion 4a provided on the inner surface of a cylindrical body, and only this flange portion 4a (same width as the conductor cover 5) is exposed on the inner circumferential wall of the insulation reinforcing tube 3. The inner circumferential wall of the cylinder 3 is a tapered inner circumferential wall whose inner diameter increases from both ends of the flange portion 4a toward both ends. [0014] The inner diameter of the insulation reinforcing tube 3 is usually made considerably larger than the outer diameter of the cable so that it can be adapted to various cable sizes. Diameter matching spacers 2a, 2b are provided on the cable la, lb insulators. The spacers 2a and 2b are made of uncrosslinked rubber/plastic material added with a crosslinking agent and have a shape that matches the shape of the gap between the inner circumferential wall of the insulation reinforcing tube 3 and the cables la and lb, and have a cylindrical shape. It may be either a body or a half body. The outer surface of the insulation reinforcing tube 3 is provided with an outer semiconductive layer 6 made of a wound layer of semiconductive tape. [0015] Next, a method for forming the above-mentioned cable connection portion will be explained based on the drawings from FIG. 3 onwards. First, when carrying out the connection method of the present invention, as shown in FIG.
The insulation reinforcing tube 3 is inserted in advance. Next, as shown in FIG. 4, the conductors 10a and 10b are connected by the conductor connecting tube 11, and the conductor cover 5 made of the half-split body is placed over the conductor connecting tube 11 and the exposed portions of the conductors 10a and 10b. Then, as shown in FIG. 5, the insulation reinforcing tube 3 inserted in advance is moved to a position where the exposed surface of the flange portion of the high voltage shield electrode 4 and the outer surface of the conductor cover 5 substantially match. [0016] After completing L, as shown in FIG. 6, diameter adjusting spacers 2a and 2b consisting of half bodies are inserted into the gap between the insulation reinforcing tube 3 and the cables la and lb. Note that when using cylindrical spacers 2a and 2b, it is necessary to insert them into the cables la and lb in advance. When the spacers 2a, 2b are completely inserted, their insertion ends 21a, 21b will come into contact with the conductor cover 5, and as a result, the positioning of the conductor cover 5 and the high voltage shield electrode 4 will be automatically achieved. [0017] That is, the inner circumferential wall of the insulation reinforcing cylinder 3 has a tapered surface with a small diameter from both ends to the center (exposed edge of the shield electrode 4), and the outer shape of the spacers 2a and 2b is the same as that of the inner circumferential wall. Since the spacers 2a and 2b match the shape of the gap, the insertion limit of the spacers 2a and 2b is limited to the exposed edge of the high voltage shield electrode 4 of the insulation reinforcing cylinder 3. When the insertion ends 21a and 21b of the spacer are brought into contact with the conductor cover 5, as a result, the high voltage shield electrode 4 and the conductor cover 5 are reliably overlapped without shifting. Therefore, even if the insulation reinforcing tube 3 is loosely fitted onto the cable connection part and the position of the high voltage shield electrode 4 is not visible, the conductor cover 5
It is possible to perform positioning. In addition, since the connection part assembled in this way is inserted so that the tapered surfaces of the outer surfaces of the spacers 2a and 2b face each other,
- Once assembled, the insulation reinforcing tube 3 does not slide in the cable axial direction, making the assembled state difficult to collapse. [0018] After inserting the spacers 2a and 2b,
An outer semiconductive layer 6 is provided by wrapping semiconductive tape or heat shrink tubing over this assembly to obtain a cable connection as shown in FIG. Thereafter, the connecting portion is placed in a mold, and heat molding is performed by applying a known method such as heating in a pressurized gas environment to complete the cable connecting portion. [0019] In the present invention, the high-voltage shield electrode 4 of the insulation reinforcing cylinder 3 and the conductor cover 5 may be fixed by means such as providing threaded portions. In this case, when moving the insulation reinforcing tube 3 to a predetermined position on the cable connection part (at the time of FIG. 5), both can be positioned and fixed. If you do it this way,
The high-voltage shield electrode 4 can be positioned more reliably, and the assembled state can be made more difficult to collapse. [00201] [Effects of the Invention] As explained above, according to the rubber/plastic cable connection method of the present invention, the high voltage shield electrode of the insulation reinforcing tube can be easily and reliably positioned by simply inserting the diameter matching spacer. Therefore, it is possible to simplify the assembly work of the connection part and improve the reliability of the electrical characteristics. [00211 In addition, in the conventional method, the insulation reinforcing tube was moved after placing the diameter adjusting spacer on the cable connection part, but in the method of the present invention, the spacer is inserted after the insulation reinforcing tube is moved to a predetermined position. This has the advantage that the assembly work of the connection part becomes easier and the assembled state is less likely to collapse. [0022]Furthermore, if the cable connection part is not in a straight line but has a slight curve, the conventional method of moving an insulating reinforcing tube with a uniform inner peripheral wall diameter onto the diameter matching spacer,
It was very difficult to move it, but the method of the present invention involves first moving the insulation reinforcing tube and then inserting the spacer.
Moreover, since the inner circumferential wall of the insulation reinforcing cylinder has a tapered diameter, insertion is easy, and the present invention has excellent effects, such as being able to flexibly accommodate slight curvature of the cable connection portion.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a cable connection section in which the rubber/plastic power cable connection method of the present invention is implemented.

FIG. 2 is a perspective view of an insulation reinforcing cylinder used in the present invention.

FIG. 3 is a cross-sectional view for explaining the first step of the connection method of the present invention.

FIG. 4 is a cross-sectional view for explaining the second procedure of the connection method of the present invention.

FIG. 5 is a cross-sectional view for explaining the third step of the connection method of the present invention.

FIG. 6 is a sectional view for explaining the fourth step of the connection method of the present invention.

FIG. 7 is a cross-sectional view of a cable connection section using a conventional connection method.

[Explanation of symbols]

la, lb cable 10a, 10b conductor 11 Conductor connection pipe 2a, 2b Diameter matching spacer 3 Insulation reinforcing tube 4 High voltage shield electrode 5 Conductor force bar

[Figure 5]

Claims (1)

[Claims] Claim 1: An insulating reinforcing cylinder having a high-voltage shield electrode in the center and a tapered inner circumferential wall whose inner diameter decreases from both ends to the center is provided on the conductor connection part of a rubber/plastic power cable. A method for connecting a rubber/plastic power cable, characterized in that a diameter matching spacer matching the shape of the gap is inserted into the gap between the cable and the inner circumferential wall of the insulation reinforcing cylinder, and then heating molding is performed.