JP5484855B2 - Power cable termination connection - Google Patents

Description

  The present invention relates to a rubber block type terminal connection portion of a power cable.

  FIG. 5 shows a rubber block type terminal connecting portion of a conventional power cable. In the figure, 1 is a rubber or plastic insulated power cable, 3 is a metal sheath exposed by stepping off the end of the power cable 1, 5 is an external semiconductive layer, 7 is an insulating layer, and 9 is a conductor. Reference numeral 11 denotes a normal temperature shrinkable rubber block mounted on the outer periphery from the outer semiconductive layer 5 to the insulating layer 7. The rubber block 11 is composed of a semiconductive rubber portion 13 for electric field relaxation and an insulating rubber portion 15, and contraction force due to expansion by the cable core (portion from the external semiconductive layer 5 to the insulating layer 7). In close contact with the outer periphery of the cable core. 17 is a conductor lead bar compression-connected to the conductor 9, 19 is a soot pipe, 21 is an upper metal fitting of the soot pipe 19, 23 is a lower metal fitting, 25 is a cable holding pipe, 27 is a waterproofing section, and 29 is filled in the soot pipe 19. Insulating compound (low viscosity silicone oil having a viscosity of about 50 to 100 cs), 31 is an oil stop processing unit that prevents the insulating compound from entering the power cable 1.

  In such a power cable terminal connection part, it is necessary to perform oil stop processing of the insulating compound 29 filled in the soot pipe 19 locally by using an oil-tight mold or a tube. Oil leakage may occur due to variations.

  In order to improve this point, an oil retaining flange is sandwiched between the lower metal fitting of the dredge pipe and the cable holding pipe, and the lower end of the rubber block is put on the cylindrical part rising in the dredge pipe from the center of this oil retaining flange. An oil stopper structure has also been proposed (see Patent Document 1).

JP 2002-315171 A

  However, in the structure using the oil retaining flange, it is necessary to sandwich the oil retaining flange between the lower metal fitting of the saddle tube and the cable holding tube, which not only complicates the structure but also makes the assembly of the terminal connection part troublesome. There's a problem.

  An object of the present invention is to provide a power cable terminal connecting portion that can perform oil retaining with a simple structure without performing oil retaining treatment and without using an oil retaining flange.

In order to achieve the above object, the present invention covers an electric field relaxation rubber block mounted on the outer periphery from an outer semiconductive layer to an insulating layer of a cable core of a power cable end portion, the power cable end portion and the rubber block. The rubber block is in close contact with the outer peripheral surface of the cable core due to the contraction force caused by being expanded in diameter by the cable core, and the insulating tube is filled with the insulating compound. In the terminal connection portion, the rubber block integrally has a portion that is in close contact with the outer peripheral surface of the cable core and an expanded cylindrical portion that has an inner diameter and an outer diameter larger than this portion, and the outer peripheral surface of the expanded diameter cylindrical portion. Is closely attached to the inner peripheral surface of the tubule.

  Moreover, it is preferable that the said rubber block is formed so that an outer peripheral surface may closely_contact | adhere to a soot pipe inner peripheral surface by the repulsive force by a diameter expansion cylinder part being diameter-reduced by a soot pipe.

  Further, the rubber block may be such that the outer peripheral surface is pressed against the inner peripheral surface of the vertical tube by a diameter-expanding member press-fitted inside the rubber tube.

  In the above power cable terminal connecting portion, it is preferable that the outer peripheral surface of the diameter-expanding member is a tapered surface whose outer diameter decreases toward the tip in the press-fitting direction.

  Further, in the above power cable terminal connection portion, an annular convex portion is formed near the lower end of the outer peripheral surface of the diameter expanding member, and the diameter increasing member is press-fitted to a predetermined position near the lower end of the inner peripheral surface of the diameter expanding cylindrical portion. It is preferable that an annular recess into which the annular projection enters when formed is formed.

  According to the present invention, since the outer peripheral surface of the rubber block is pressed against the inner peripheral surface of the soot tube, it is possible to prevent leakage of the insulating compound in the soot tube with a simple structure without using an oil retaining flange. Further, since the insulating compound only needs to be filled above the rubber block, there is an advantage that the amount of the insulating compound used can be reduced.

  Providing the rubber block with the enlarged diameter cylindrical portion as described above has an advantage that the rubber block can be easily adhered to the inner peripheral surface of the soot tube.

  If the outer peripheral surface of the rubber block diameter-expanding cylinder part is in close contact with the inner peripheral surface of the steel pipe due to the repulsive force caused by the diameter reduction by the steel pipe, the inner surface of the steel pipe and the rubber block are naturally adhered to each other. There are advantages to being.

  Further, when the diameter-enlarged cylindrical portion is expanded by the diameter-enlarging member, the outer peripheral surface of the diameter-enlarged cylindrical portion can be pressed more strongly against the inner peripheral surface of the soot tube, so that the oil stop effect is improved.

  Moreover, if the outer peripheral surface of a diameter-expansion member is made into a taper surface, the diameter-expansion member can be easily press-fitted into the inside of the diameter-expansion cylindrical portion.

  Furthermore, an annular convex portion is formed near the lower end of the outer peripheral surface of the diameter-expanding member, and an annular concave portion into which the annular convex portion enters near the lower end of the inner peripheral surface of the enlarged-diameter cylindrical portion. And the annular recess can be prevented from coming out.

Sectional drawing which shows one Example of the power cable termination | terminus connection part which concerns on this invention. Sectional drawing of the rubber block used for the termination | terminus connection part of FIG. Sectional drawing which shows the other Example of the power cable termination | terminus connection part which concerns on this invention. The expanded sectional view of the principal part of the termination | terminus connection part of FIG. Sectional drawing which shows an example of the conventional electric power cable termination | terminus connection part.

<Example 1> FIG. 1: shows one Example of the power cable termination | terminus connection part which concerns on this invention. In FIG. 1, the same reference numerals are given to the same portions as the terminal connection portion of FIG. 5 described above. The rubber block 11 used in this terminal connection portion is lower than the portion (electric field relaxation portion) that is in close contact with the outer peripheral surface from the outer semiconductive layer 5 to the insulating layer 7 of the cable core, and both the inner diameter and the outer diameter are larger than the portion. The enlarged diameter cylindrical portion 33 is formed integrally with the insulating rubber portion 15.

  In the free state before the external force is applied, the rubber block 11 has an inner diameter d of the electric field relaxation portion smaller than the outer diameter of the cable core and an outer diameter D of the enlarged diameter cylindrical portion 33 as shown in FIG. It is made to be larger than the inner diameter.

  Therefore, when the rubber block 11 is mounted on the outer periphery of the cable core, the diameter is expanded by the cable core, so that a contracting force is generated, and the contracting force is brought into close contact with the outer peripheral surface of the cable core so that an electric field relaxation effect can be exhibited. . Furthermore, if the outer periphery of the rubber block 11 is covered with the tub tube 19, the diameter-expanded cylindrical portion 33 is reduced in diameter by the inner peripheral surface of the tub tube 19. It comes into close contact with the peripheral surface and is in a state where oil leakage of the insulating compound 29 filled in the soot tube 19 can be prevented. As the insulating compound 29, it is preferable to use a high-viscosity silicone oil having a viscosity of about 1,000 to 10,000 cs.

  With such a structure, the oil retaining process can be performed by covering the soot tube 19, so that it is not necessary to perform the oil retaining process on the metal sheath 3, and it is not necessary to use the oil retaining flange. Oil stop processing can be performed.

<Example 2> FIG.3 and FIG.4 shows the other Example of the power cable termination | terminus connection part which concerns on this invention. 3 and 4, the same parts as those in FIG. 1 are denoted by the same reference numerals. The rubber block 11 used in this terminal connection portion is also larger than the portion (electric field relaxation portion) that is in close contact with the outer peripheral surface from the outer semiconductive layer 5 to the insulating layer 7 of the cable core, and has an inner diameter and an outer diameter larger than the portion. The enlarged diameter cylindrical portion 33 is formed integrally with the insulating rubber portion 15, and the feature of this terminal connection portion is that the diameter enlarged member 35 is press-fitted into the enlarged diameter cylindrical portion 33 to increase the diameter. The cylindrical portion 33 is expanded in diameter so that the outer peripheral surface of the expanded cylindrical portion 33 is in close contact with the inner peripheral surface of the soot tube 19.

  With such a structure, the outer peripheral surface of the enlarged diameter cylindrical portion 33 can be more closely attached to the inner peripheral surface of the soot tube 19, so that a higher oil stop effect can be obtained. In the case of this embodiment, since the diameter-expanded cylindrical portion 33 is expanded by the diameter-expanding member 35, the outer diameter of the diameter-expanded cylindrical portion 33 in the free state before the external force is applied to the rubber block 11 is It may not be larger than the inner diameter of the soot tube 19, and may be approximately the same as the inner diameter of the soot tube 19.

  The outer peripheral surface of the diameter-expanding member 35 is a tapered surface whose outer diameter decreases toward the tip, and the inner peripheral surface of the diameter-expanded cylindrical portion 33 is a tapered surface corresponding thereto. This is to facilitate the press-fitting of the diameter-expanding member 35 into the inside of the diameter-expanding cylindrical portion 33.

  Further, as shown in FIG. 4, an annular convex portion 37 is formed near the lower end of the outer peripheral surface of the diameter expanding member 35, and an annular concave portion 39 is formed near the lower end of the inner peripheral surface of the expanded diameter cylindrical portion 33. Yes. This is because the annular protrusion 37 enters the annular recess 39 when the diameter-expanding member 35 is press-fitted to a predetermined position, thereby preventing the diameter-expanding member 35 from coming out.

  Furthermore, the diameter-expanding member 35 of this embodiment is formed so that the tip portion enters between the semiconductive rubber portion 13 and the insulating rubber portion 15 and presses the semiconductive rubber portion 13 in the radial direction from the outer peripheral surface. Yes. This is because the semiconductive rubber portion 13 is more strongly pressed against the outer peripheral surface of the cable core to obtain a more stable electric field relaxation effect.

1: Power cable 3: Metal sheath 5: External semiconductive layer 7: Insulating layer 9: Conductor 11: Rubber block 13: Semiconductive rubber part 15: Insulating rubber part 17: Conductor lead bar 19: Steel pipe 29: Insulating compound 33: Expanded cylindrical portion 35: Expanded diameter member 37: annular convex portion 39: annular concave portion

Claims (5)

An electric field relaxation rubber block attached to the outer periphery of the cable core of the power cable terminal portion from the outer semiconductive layer to the insulating layer, and a soot tube arranged to cover the power cable terminal portion and the rubber block, The rubber block is in close contact with the outer periphery of the cable core due to the contraction force caused by being expanded by the cable core, and in the power cable terminal connection portion in which the insulation tube is filled with the insulating compound,
The rubber block integrally has a portion that is in close contact with the outer peripheral surface of the cable core and an enlarged cylindrical portion that has an inner diameter and an outer diameter that are larger than the outer peripheral surface. A power cable terminal connecting portion characterized by being in close contact with the cable. It said radially enlarged tube portion of the rubber block, power cable sealing end according to claim 1, wherein the outer peripheral surface with a repulsive force by being reduced in diameter is characterized in that it is in close contact with the inner peripheral surface porcelain bushing by the porcelain bushing. Diameter cylinder portion of the rubber block, power cable sealing end according to claim 1, wherein the outer peripheral surface is pressed against the inner circumferential surface porcelain bushing by the enlarged diameter member which is press-fitted therein. 4. The power cable terminal connecting portion according to claim 3 , wherein the outer peripheral surface of the diameter-expanding member is a tapered surface whose outer diameter decreases toward the tip in the press-fitting direction. An annular convex portion is formed in the vicinity of the lower end of the outer peripheral surface of the diameter expanding member, and the annular convex portion enters in the vicinity of the lower end of the inner peripheral surface of the diameter expanding cylindrical portion when the diameter expanding member is press-fitted to a predetermined position. The power cable terminal connecting portion according to claim 3 or 4, wherein an annular recess is formed.

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