JP2678317B2 - Three-pronged branch pipe for power cable - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a three-pronged branch pipe for a power cable, which is used for a branch portion of a single-core cable of each line, such as a terminal portion of a three-phase power cable. is there.

[Prior Art] Conventionally, in a three-phase power cable, a three-pronged branch pipe is often attached at a connecting portion, a terminating portion, or the like in order to safely and reliably branch each single-core cable.
As shown in FIGS. 7 (a) and 7 (b), the most commonly used three-pronged branch pipe 1 is a large tubular portion 2 into which a three-phase power cable is inserted together with an exterior portion, and the large tubular portion 2. It is composed of three branch cylinders 3a, 3b, 3c that branch the upper part of the branch into three branches, and the single core cables of the respective strips are inserted into the respective branch cylinders 3a, 3b, 3c.

The cable end portion into which the three-pronged branch pipe 1 is attached is
The outer portion 4 of the power cable is removed as shown in the figure,
It is branched into three single-core cables 5a, 5b, 5c, and the above-mentioned three-pronged branch pipe 1 is inserted at the root of the branch. At this time, the outer periphery of the three-pronged branch pipe 1 in the vicinity of both ends is covered with a protective insulating tape from the large tubular portion 2 to the exterior portion 4 and the branched tubular portions 3a, 3b, 3c to the single core cables 5a, 5b, 5c of the respective strips. 6 is wound, waterproofing and strengthening of seams and single core cables 5a, 5b,
Insulation reinforcement is applied to the 5c side. In this case, the ground wire 7 may be pulled out from the barrier layer of each of the single-core cables 5a, 5b, 5c.

[Problems to be Solved by the Invention] As described above, the three-pronged branch pipe 1 is fixed to the power cable by protecting the outer periphery from both ends of the three-pronged branch pipe 1 to the exterior portion 4 and the single-core cable, respectively. It is performed by winding the insulating tape 6. When winding the insulating tape 6, it is necessary to set the winding start position on the side of the trifurcated branch pipe 1 to a predetermined position in order to keep the waterproof and insulating properties constant. It is extremely troublesome to work while measuring, and there is a great risk of incorrect work. In particular, when the trifurcated branch pipe 1 is miniaturized, if the winding start position is wrong, the relative error increases, and there is a risk that the waterproof / insulation characteristics are greatly affected. This hinders the miniaturization of the branch pipe 1, that is, the miniaturization of the terminal portion of the power cable and the structure of the connecting portion.

An object of the present invention is to solve the above problems and to easily determine a predetermined winding end position when winding an insulating tape without error, so that even if the size is reduced, a predetermined waterproof property is obtained. -To provide a three-pronged branch pipe for a power cable that can maintain insulation characteristics.

[Means for Solving the Problems] In order to achieve the above-mentioned object, in a three-pronged branch pipe for a power cable according to the present invention, a large tube portion into which a three-core cable is inserted, and each of the three-core cables are branched. A power cable having three branch tubes through which a single-core cable is inserted, and a predetermined cable is inserted into each of the large tube portion and each branch tube, and an insulating tape is wound between the cables to fix the cable. A three-pronged branch pipe for use, wherein the winding portion of the insulating tape on the peripheral surface of each of the large tubular portions and each branching tube is flat, and a convex ring is provided around each winding end of the insulating tape. It is characterized by

[Operation] In the three-pronged branch pipe for the power cable having the above-described configuration, the convex ring provided around the branch pipe indicates the predetermined winding end position of the insulating tape.

Embodiment The present invention will be described in detail based on the embodiment shown in FIGS. The same reference numerals as those of the conventional example indicate the same members.

FIG. 1 shows a connecting portion of a power cable for driving, for example, a three-phase high-voltage electric motor, and FIG. 2 shows a sectional view seen from the side. The outer sheath 4 at the end of the power cable is removed and branched into three single-core cables 5a, 5b, 5c, and the three-branch branch pipe 10 made of chloroprene rubber, ethylene propylene rubber, or the like is provided at the root of the branch. Is attached. As shown in FIG. 3 and FIG. 4, the three-pronged branch pipe 10 has a large tubular portion 11 into which a three-phase power cable is inserted together with the exterior portion 4 from below, and an upper portion of the large tubular portion 11 is branched into three branches. Three
The branch cylinders 12a, 12b, 12c are formed of a book, and the lower end open part of the large cylinder part 11 and the upper end open parts of the branch cylinders 12a, 12b, 12c are formed so that the cylinder wall becomes thinner toward the tip. . Then, the cable portion that is not branched to the large tube portion 11 and the single core cables 5a, 5b, and 5 that are branched to the branch tubes 12a, 12b, and 12c.
c is inserted respectively, and the winding portion of the protective insulating tape 13 on the outer periphery of each of the large cylinder portion 11 and the branch cylinders 12a, 12b, 12c is flat, and a predetermined winding start or end position. Convex rings 14 and 15 are integrally provided around the outer peripheral surface of the.

To fix the three-pronged branch pipe 10 to the power cable and to reinforce the insulation, attach the three-pronged branch pipe 10 to the power cable, and then attach the protective insulating tape 13 from the convex ring 14 of the large tubular portion 11 to the cable exterior portion on the lower side. As for 4, the branch parts 12a, 12b,
Each single core cable 5a, 5b, 5 above the convex ring 15 of 12c
It is done by winding in both ranges up to c. When winding, a predetermined winding range can be realized simply by using the convex rings 14 and 15 as the ends of the winding, and there is little risk of erroneous work, for example, a conventional trifurcated branch pipe of about 180 mm. Even if the overall length of the product is reduced to about 50 mm, the specified waterproof and insulating properties can be easily obtained.

Further, in FIG. 1 and FIG. 2, each single core cable 5a, 5b, 5c branched by the three-pronged branch pipe 10 is formed of ethylene propylene rubber or the like around the tip end portion thereof, and has a length of 70 mm, for example. Hollow spindle type rubber stress cone 20
Are inserted respectively. These stress cones 20
Has a hollow portion 21 through which the single-core cables 5a, 5b, 5c are inserted as shown in FIG. 6, and a rubber insulating portion 22 and a semiconductor layer portion 23 are provided.
The rubber insulating portion 22 is integrally provided with, for example, three convex rings 24 at equal intervals on the outer peripheral surface of the large diameter portion of the rubber insulating portion 22. The flat portion between the convex rings 24 has a different color for each stress cone 20 for later phase discrimination, for example, red, blue,
Each of the colored tapes made of white synthetic resin material can be wound, and the height of the convex ring 24 is substantially equal to the thickness of the wound colored tape. Then, recesses 25 and 26 for winding the protective insulating tape are formed on the outer circumferences near both ends of the stress cone 20.

Here, as shown in FIGS. 1 and 2, the semiconductive layer portion 23
Are connected by winding the respective outer semiconductive layers 31 of the single-core cables 5a, 5b, 5c and the semiconductive tape 32, and the convex portion 25 at the lower end of the stress cone 20 is further connected to a three-pronged branch pipe. The protective insulating tape 13 for fixing 1 is the branch cylinders 12a, 12b, 12
By continuously winding from c to the position shown by the dotted line in FIG. 6, and by winding another insulating tape 13 ′ in the recess 26 at the upper end, the stress cones 20 are made into single core cables respectively.
It is fixed to 5a, 5b and 5c. On the other hand, each single-core cable 5
The conductor 33 is exposed from the ends of a, 5b, and 5c, and is connected to the motor-side lead wires 35a, 35b, and 35c of the high-voltage motor (not shown) through the connection terminals 34, respectively, and the insulating tape 36 is provided thereon. Is wound.

By having such a configuration, the single-core cable 5a,
Since the stress cone 20 is attached to the 5b and 5c, the stress cone 20 can alleviate the electrical stress which is the original purpose, and the stress cone 20 is attached to the single core cables 5a, 5b and 5c. With the convex ring 24, slippage is reduced, workability upon insertion is improved, and further, the protective insulating tape 13 wound around the stress cone 20,
The 13 'can satisfy the insulation characteristics without filling the number of turns only by filling the recesses 25 and 26, and can obtain a smooth shape without rising as a step.

Instead of the above-mentioned three-pronged branch pipe 10, a three-pronged branch pipe 10 'as shown in FIG. 5 may be used. This three-pronged branch pipe 1
In 0 ', another convex ring 16 and 17 is provided outside the convex rings 14 and 15, respectively, in parallel with the convex rings 14 and 15. In this case, the insulating tape 13 is a convex ring.
If the winding start position is 14 or 15, the convex ring 1
6 and 17 will be buried by the insulating tape 13.
The convex rings 16 and 17 act to lock the movement of the insulating tape 13, and effectively prevent the wound insulating tape 13 from being displaced from the large cylinder portion 11 and the branch pipes 12a, 12b, and 12c. In the related art, the large tubular portion 11 and the branch pipes 12a, 12b, 12 were used to prevent the pressure-bonded and wound insulating tape 13 from being displaced by surface friction.
c can reduce the area of its outer peripheral surface. Therefore, in the above-described three-pronged branch pipe 10 ', it is possible to further reduce the total length of the large tubular portion 11 and the branched pipes 12a, 12b, 12c, and eventually the three-pronged branch pipe 10'.

Incidentally, in the above embodiment, the convex ring 14, 15, 1
It is preferable that 6 and 17 are provided over the entire circumference of the large tubular portion 11 and the branch portions 12a, 12b and 12c, but there is no problem even if they are provided partially.

[Effects of the Invention] As described above, the three-pronged branch pipe for a power cable according to the present invention, when winding an insulating tape, facilitates a predetermined winding start position without error by a circumferentially arranged convex ring. Therefore, it is easy to wind while maintaining the prescribed waterproof / insulation characteristics, and even if it is downsized, the waterproof / insulation characteristics of the winding part can be kept good, and the branch pipe and thus the power cable It is easy to downsize the terminal unit and the connection unit.

[Brief description of the drawings]

1 to 6 show an embodiment of a three-pronged branch pipe for a power cable according to the present invention, FIG. 1 is a front view of a terminal portion of a power cable, and FIG. 2 is a cross-sectional view as seen from the side. FIG. 3 is a front view of a trifurcated branch pipe, FIG. 4 is a plan view, FIG. 5 is a front view of a trifurcated branch pipe according to another embodiment, and FIG. 6 is a sectional view of a stress cone. FIG. 8A is a plan view of a conventional three-pronged branch pipe, FIG. 8B is a front view, and FIG. 8 is a front view of a conventional power cable terminal portion. Reference numeral 4 is a power cable exterior portion, 5a, 5b and 5c are single-core cables, 10 and 10 'are three-pronged branch pipes, 11 is a large tube portion, 12a, 12b and 12
c is a branch cylinder, 13 and 13 'are insulating tapes, 14, 15, 16 and 17 are convex rings, and 20 is a stress cone.

Continued front page (72) Inventor Isao Okamoto 1008 Shinbori, Kumagaya, Saitama Mitsubishi Cable Industries, Ltd. Kumagaya Manufacturing Co., Ltd. (72) Yoshiki Kita 1008 Shinbori, Kumagaya, Saitama Mitsubishi Cable Industries, Ltd. (72) Inventor Shizuho Maeda 1008, Shinbori, Kumagaya-shi, Saitama Mitsubishi Cable Industries, Ltd. Kumagaya Manufacturing Co., Ltd. (56) References )

Claims (1)

(57) [Claims] 1. A large cylinder portion into which a three-core cable is inserted, and three branch cylinders into which single-core cables branched from the three-core cable are inserted, respectively, and the large cylinder portion and the branch cylinders are respectively provided with predetermined ones. A three-pronged branch pipe for a power cable, in which an insulating tape is wound around and fixed to the cable in a state where the cable is inserted, wherein the large cylinder portion and the wound portion of the insulating tape on the peripheral surface of each branch cylinder. Is a flat shape, and a convex ring is provided around each winding end position of the insulating tape.