JP4801182B2 - Rubber unit and cable connection using the same - Google Patents

Description

  The present invention relates to a rubber unit and a cable connecting portion using the rubber unit, and more particularly to a rubber unit mounted on the outer periphery of a cable insulator of a high-voltage CV cable (crosslinked polyethylene cable) and a cable connecting portion using the rubber unit.

  Conventionally, a rubber block using a so-called one-piece / pre-molded rubber unit that utilizes the self-shrinking force of rubber from the viewpoint of making the intermediate connection portion of a high-voltage CV cable of 66 kV or higher compact and highly reliable. Insulated intermediate connection portions are implemented (for example, Patent Documents 1 and 2, Non-Patent Documents 1 and 2).

  FIG. 12 shows a longitudinal sectional view of the main part of such a rubber block insulation type intermediate connection part. In this figure, the rubber block insulation type intermediate connection portion is formed on a conductor connection portion 200 of a high voltage CV cable formed by compressing and connecting a pair of cable conductors (not shown) with a connection sleeve 100, and on the outer periphery of the conductor connection portion 200. And a cylindrical rubber unit 400 that is inserted between the outer circumferences of the pair of cable insulators 300a and 300b.

  Here, the rubber unit 400 is composed of a cylindrical main insulator 500 made of a silicone rubber material, and a semiconductive silicone rubber material integrally embedded in the inner peripheral surface of the central portion of the main insulator 500. The inner semi-conductor 600, the stress cones 700a and 700b made of semi-conductive silicone rubber material integrally embedded in the inner peripheral surfaces of both ends of the main insulator 500, and the outer periphery of the main insulator 500 are provided. And an external semiconductive layer 800 made of a semiconductive coating layer or a semiconductive rubber layer. Note that the inner diameter of the insertion part of the rubber unit 400 is slightly smaller than the outer diameter of the cable insulators 300a and 300b.

  The rubber unit 400 having such a configuration is inserted between the outer periphery of the pair of cable insulators 300a and 300b on the outer periphery of the conductor connecting portion 200 by using a diameter expansion jig (not shown) such as a spiral core. Due to the self-shrinkage force, the cable insulators 300a and 300b are brought into close contact with the outer periphery, thereby ensuring the insulation performance in the rubber block insulating intermediate connection portion.

  According to the rubber unit 400 having such a configuration, the rubber unit 400 can be easily contracted and adhered to the outer periphery of the cable insulators 300a and 300b at the construction site by simply pulling out the spiral core without requiring a special tool. Since it can be used, it is excellent in workability.

  However, in the rubber block insulation type intermediate connection portion having such a configuration, the surface pressure with the interface of the cable insulators 300a and 300b is obtained by the contraction force of the rubber unit 400, as shown in FIG. When the electric field strength of the rising portion A of the stress cones 700a and 700b embedded in the end portion of the rubber unit 400 is highest, a surface corresponding to the electric field strength of the rising portion A as shown in FIG. Since the pressure is applied with a constant tightening force over the entire length of the rubber unit 400, the surface of the portions other than the rising portion A of the stress cones 700a and 700b (filled portion in FIG. 13B) is more than necessary. Pressure is applied. In the figure, reference numeral 900 denotes an equipotential line.

  Therefore, in the rubber block insulation type intermediate connection portion having such a configuration, the required maximum surface pressure is applied with a constant tightening force over the entire length of the rubber unit 400, so that the rubber unit 400 has excellent elongation characteristics. In addition, the rubber unit 400 has to be second vulcanized in order to stabilize its physical properties after the rubber unit 400 is first vulcanized, and the overall material cost and processing cost are high. There was a difficulty of becoming.

  Further, it is necessary to increase the diameter expansion force of the rubber unit 400 by a diameter expansion member such as a spiral core, and further, when the rubber unit 400 is stored for a long time with the diameter expansion force of the rubber unit 400 increased. There is a problem that the tightening force of the rubber unit 400 is reduced.

  On the other hand, in the rubber unit 400 applied to the intermediate connection portion of the high voltage CV cable of 33 kV or less, it can be inserted and attached to the outer periphery of the cable insulators 300a and 300b without using a diameter expansion jig such as a spiral core. However, in the so-called slide assembly method (for example, Non-Patent Documents 3 and 4) of the rubber unit 400 that does not use a diameter expansion jig such as a spiral core, the tightening margin of the rubber unit 400 (the inner diameter of the rubber unit 400). Is required to slide the rubber unit 400 along the outer peripheral surfaces of the cable insulators 300a and 300b. Met. In particular, when applied to an intermediate connection portion of a 33 kV class high-voltage CV cable, there is a problem that considerable labor is required. Therefore, when applied to an intermediate connection portion of a high voltage CV cable of 66 kV class or higher, the outer diameter of the rubber unit 400 is increased, and the interference between the rubber unit 400 and the cable insulators 300a and 300b needs to be increased. Therefore, the slide assembly method of the rubber unit 400 has a drawback that it cannot be substantially applied to an intermediate connection portion of a high voltage CV cable of 66 kV class or higher.

JP 2000-37029 A JP 2008-61416 A

Furukawa Electric Times Issue 104 (July 1999) 81-86 Mitsubishi Electric Industrial Time Report No. 98 (October 2001) 45-49 Showa Electric Wire Review Vol.55, No.1 (2005) 21-24 2006 IEEJ National Convention 7-122

  The present invention has been made to solve the above-mentioned problems, and by reducing the surface pressure distribution of the rubber unit with respect to the cable insulator to the electric field strength distribution as much as possible, the surface pressure is reduced, and as a result, assembly. The purpose is to provide a cable connection part that is skillless by using a rubber unit that is easy to construct.

  A rubber unit according to a first aspect of the present invention includes an insulating cylinder made of an elastic material, and a cylindrical metal fitting concentrically provided integrally with the insulating cylinder at at least one end of the insulating cylinder. A cylindrical stress cone is embedded concentrically with the insulating cylinder in the inner periphery of the end portion facing the metal fitting of the tube, and the metal fitting faces the stress cylinder of the first cylindrical portion and the first cylindrical portion. A second cylindrical portion concentrically connected to the first cylindrical portion is provided at the end opposite to the end portion, and the end facing the metal fitting of the insulating cylinder extends toward the second cylindrical portion. A cylindrical outer extension is provided, the inner peripheral surface of which can be attached to the outer peripheral surface of the second cylindrical portion, and the end facing the metal fitting of the stress cone faces the first cylindrical portion. A cylindrical inner extension is provided, the inner peripheral surface of which can be attached to the outer peripheral surface of the first cylindrical portion. The inner peripheral surface of the portion is integrally bonded to the outer peripheral surface of the second cylindrical portion, and the inner peripheral surface of the inner extension portion is attached to the outer peripheral surface of the first cylindrical portion in an unbonded state. It is.

  A rubber unit according to a second aspect of the present invention includes an insulating cylinder made of an elastic material, and a cylindrical metal fitting concentrically provided integrally with the insulating cylinder at at least one end of the insulating cylinder. A cylindrical stress cone is embedded concentrically with the insulating cylinder at the end of the cylinder facing the metal fitting, and the metal fitting is opposite to the first cylinder and the end of the first cylinder facing the stress cone. A second cylindrical portion concentrically connected to the first cylindrical portion at the end on the side, and an annular recessed portion that can be attached to the outer peripheral surface of the metal fitting at the end facing the metal fitting of the stress cone The inner peripheral surface located on the end side opposite to the end facing the stress cone is integrally bonded to the outer peripheral surface of the second cylindrical portion. The inner peripheral surface located on the end facing the stress cone of the inner peripheral surface of the first portion is opposite to the outer peripheral surface of the first cylindrical portion. It is what is deposited in a non-adhesive state Te.

  According to a third aspect of the present invention, in the rubber unit according to the first aspect, an annular groove or protrusion is provided on the outer peripheral surface of the first cylindrical portion in the vicinity of the second cylindrical portion. An annular protrusion or groove that can be fitted into the groove or protrusion is provided on the inner periphery of the inner extension.

  According to a fourth aspect of the present invention, in the rubber unit according to the second aspect, an annular groove or protrusion is provided on the outer peripheral surface of the first cylindrical portion in the vicinity of the second cylindrical portion, An annular protrusion or groove that can fit into the groove or protrusion is provided on the inner periphery of the recess.

  According to a fifth aspect of the present invention, in the rubber unit according to any one of the first to fourth aspects, the outer peripheral edge of the end opposite to the end opposite to the stress cone of the metal fitting The flange portion is continuously provided outward in the radial direction.

  The cable connection part which is a 6th aspect of this invention is a conductor connection part of the power cable formed by connecting the cable conductors of a pair of power cables, and any one of the first to fifth aspects. A rubber unit is provided, and the rubber unit is elastically attached to the outer periphery of the conductor connection portion across the outer periphery of the cable insulator constituting the pair of power cables.

  The cable connecting portion according to the seventh aspect of the present invention includes a cable terminal portion in which a cable insulator is exposed by a stripping process, and a soot tube that surrounds the cable terminal portion and has a lower metal fitting on its low-pressure side. And a rubber unit according to any one of the first to fifth aspects, wherein the rubber unit is mounted on the outer periphery of the cable insulator with the metal part constituting the rubber unit facing the lower metal part side. Is fixed to the lower metal fitting through an O-ring.

  The cable connection portion according to the eighth aspect of the present invention includes a cable terminal portion in which a cable insulator is exposed by a stripping process, and a soot tube surrounding the cable terminal portion and having a lower metal fitting disposed on its own low pressure side. And a rubber unit according to any one of the first to fifth aspects, and a cylindrical adapter disposed between the lower metal fitting and the rubber unit and having a flange portion on the high-pressure side, In the cable insulator, a metal fitting constituting the rubber unit is mounted on the outer periphery of the cable insulator toward the adapter side, and the metal fitting is fixed to the flange portion via an O-ring.

  According to the rubber unit of the first to eighth aspects of the present invention and the cable connecting portion using the rubber unit, the following effects are obtained.

  First, a large clamping force can be generated in the vicinity of the stress cone cable insulator and the surface pressure can be applied intensively to the high electric field strength portion of the rising portion of the stress cone. As a result, the surface pressure distribution can be matched to the electric field strength distribution as much as possible, and the tightening force of the entire rubber unit can be reduced by designing a rubber unit having a small diameter difference.

  Second, by using a rubber unit in which the surface pressure distribution matches the electric field strength distribution as much as possible and the tightening force of the entire rubber unit is reduced, that is, a rubber unit designed with a small diameter difference is used. By using it, stable insulation can be ensured even in a so-called self-compression slide type in which the rubber unit is slid.

  Third, the rubber unit designed with a small diameter difference can be slid to easily insert the rubber unit into the cable insulator.

  Fourth, since the connecting portion of the high-pressure CV cable can be assembled by a self-compression slide type, a diameter-enlarged holding member such as a spiral core is not necessary, and cost can be reduced.

  Fifth, by attaching the metal fitting of the rubber unit toward the lower metal fitting and fixing the metal fitting to the lower metal fitting via an O-ring or to a cylindrical adapter disposed between the rubber unit and the lower metal fitting. The number of parts can be reduced as compared with the conventional seal portion (oil stop portion), and the sealing performance of the seal portion (oil stop portion) can be greatly improved.

  Sixth, since there is no need to use metal fittings and tape seals dedicated to oil stoppers as in the past, and no operator skills are required, there is no variation in airtightness at the seal part, and assembly is simplified. Can be achieved.

  Seventh, the reliability of the seal portion can be greatly improved by the seal structure using the O-ring.

  Eighth, in one part of the adhesive portion between the outer peripheral surface of the first cylindrical portion of the metal fitting near the second cylindrical portion and the inner periphery of the inner extension of the stress cone, one of the fittings is an annular groove. When the other is constituted by an annular projection, the metal fitting and the stress cone can be integrated with a stronger adhesion state.

The partial sectional view of the rubber unit in the 1st example of the present invention. The exploded sectional view of the rubber unit in the 1st example of the present invention. The partial sectional view of the cable connection part (intermediate connection part) in the 2nd example of the present invention. Explanatory drawing which shows the state before the assembly of the rubber unit in the 2nd Example of this invention, and after an assembly. Explanatory drawing which shows the provision condition of the electric field and surface pressure of a cable connection part (intermediate connection part) in 2nd Example of this invention. The partial sectional view of the rubber unit in the 3rd example of the present invention. The partial sectional view of the cable connection part (termination connection part) in the 4th example of the present invention. Explanatory drawing which shows the state before the assembly of the rubber unit in the other Example of this invention, and the state after an assembly. Explanatory drawing which shows the state before the assembly of the rubber unit in the other Example of this invention, and the state after an assembly. The partial sectional view of the rubber unit in other examples of the present invention. The partial sectional view of the rubber unit in other examples of the present invention. The partial cross section figure of the conventional rubber block insulation type intermediate connection part. Explanatory drawing which shows the provision condition of the electric field and surface pressure in the conventional rubber block insulation type intermediate | middle connection part.

  BEST MODE FOR CARRYING OUT THE INVENTION The best embodiment to which a rubber unit of the present invention and a cable connecting portion using the same are applied will be described below with reference to the drawings.

  FIG. 1 is a longitudinal sectional view of a rubber unit of the present invention suitable for an intermediate connection part of a 110 to 132 kV class high voltage CV cable.

  In the figure, a rubber unit Ua of the present invention includes an insulating cylinder 1a formed of an elastic material, for example, a silicone rubber material, and a cylindrical shape provided integrally with both ends of the insulating cylinder 1a concentrically with the insulating cylinder 1a. Metal fittings 2a and 2b are provided.

  The insulating cylinder 1a includes a cylindrical main insulator 10a, and cylindrical outer extensions 11a extending toward the metal fittings 2a and 2b, respectively, at outer peripheral edges of both ends of the main insulator 10a, 11b is provided concentrically with the main insulator 10a. Further, on the inner peripheral surface side of the end portion of each outer extension portion 11a, 11b, annular thick portions 12a, 12b whose inner peripheral surface can be attached to the outer peripheral surfaces of metal fittings 2a, 2b described later. Is provided. Here, the outer peripheral surface of the cylindrical main insulator 10a and the outer peripheral surface of the cylindrical outer extension portions 11a and 11b are formed to be flush with each other, and the inner periphery of the annular thick portions 12a and 12b The surface and the inner peripheral surfaces of inner extensions 43a and 43b of stress cones 4a and 4b described later are formed so as to be flush with each other.

  An inner semiconductor made of a cylindrical semiconductive elastic material, for example, a semiconductive silicone rubber material, is formed on the inner peripheral surface of the central portion of the main insulator 10a, and a cylindrical shape is formed on the inner peripheral surfaces of both ends. Stress cones 4a and 4b made of a semiconductive elastic material, for example, a semiconductive silicone rubber material, are respectively embedded and molded concentrically with the main insulator 10a. Here, the inner peripheral surface of the inner semiconductor 3 and the pair of stress cones 4a and 4b are formed to be flush with the inner peripheral surface of the main insulator 10a.

  As shown in FIG. 2A, the pair of stress cones 4a and 4b includes electric field relaxation portions 41a and 41b each having a tapered inner peripheral surface that expands in a trumpet shape toward the outer periphery of the central portion of the main insulator 10a. And have thick cylindrical portions 42a, 42b on the side facing the metal fittings 2a, 2b, and on the outer surface of the metal fittings 2a, 2b on the side facing the metal fittings 2a, 2b of each cylindrical portion 42a, 42b. An annular inner extension 43a, 43b that can be deposited is provided. In addition, annular protrusions 44a and 44b are provided on the inner circumferences of the ends of the inner extensions 43a and 43b on the side facing the metal fittings 2a and 2b. Here, the axial lengths of the outer extensions 11a and 11b are approximately twice the axial length of the inner extensions 43a and 43b.

  The metal fittings 2a and 2b are each formed of aluminum or the like, and as shown in FIG. 2 (b), first cylindrical portions to which the inner peripheral surfaces of the inner extensions 43a and 43b of the stress cones 4a and 4b are attached, respectively. 21a, 21b and second cylindrical portions 22a, 22b to which the inner peripheral surfaces of the outer extension portions 11a, 11b are attached, and the second cylindrical portions 22a, 22b are the first cylindrical portions 21a, 21b. The first cylindrical portions 21a and 21b are concentrically connected to the end opposite to the end facing the stress cones 4a and 4b.

  In addition, annular concave grooves 23a and 23b are provided on the outer peripheral surfaces of the first cylindrical portions 21a and 21b in the vicinity of the second cylindrical portions 22a and 22b. The inner diameters of the metal fittings 2a and 2b are larger than the outer diameters of the cable insulators 81a and 81b described later, and the outer diameters of the metal fittings 2a and 2b are the inner diameters of the inner extensions 43a and 43b of the stress cones 4a and 4b. The inner diameter of the thick portions 12a and 12b of the insulator 10a is substantially the same.

  Next, a method of integrating the main insulator 10a as the insulating cylinder 1a, the internal semiconductor 3, the pair of stress cones 4a and 4b, and the metal fittings 2a and 2b will be described.

  First, as shown in FIG. 2 (b), semiconductive adhesives 6a and 6b, for example, semiconductive rubber paste-like adhesives and silanes, only in the concave grooves 23a and 23b of the metal fittings 2a and 2b. In this state, a primer for vulcanization adhesion mainly composed of a coupling agent is applied, and in this state, the inner extensions 43a of the pair of stress cones 4a and 4b molded in advance as shown in FIG. The first cylindrical portions 21a and 21b of the metal fittings 2a and 2b are mounted in 43b. As a result, as shown in FIG. 2 (c), the inner peripheral surfaces of the inner extensions 43a and 43b excluding the protrusions 44a and 44b of the stress cones 4a and 4b are the first excluding the grooves 23a and 23b of the metal fittings 2a and 2b. It adheres to the outer peripheral surface of 1 cylindrical part 21a, 21b in a non-adhesive state. Further, the protrusions 44a and 44b provided on the inner peripheral surfaces of the inner extensions 43a and 43b of the stress cones 4a and 4b are fitted into the concave grooves 23a and 23b, and the protrusions of the stress cones 4a and 4b at the fitting parts. Only the portions 44a and 44b are integrated with the metal fittings 2a and 2b in a stronger adhesive state. As a result, only the inner periphery on the end side of the pair of stress cones 4a and 4b is more firmly fixed to the metal fittings 2a and 2b, and the detachment from the metal fittings 2a and 2b is prevented.

  Next, as shown in FIG. 2 (c), adhesives 7a and 7b similar to the semiconductive adhesives 6a and 6b are applied to the outer circumferences of the second cylindrical portions 22a and 22b constituting the metal fittings 2a and 2b. Apply. Then, the stress cones 4a and 4b with the pair of metal fittings 2a and 2b and the preliminarily molded internal semiconductor 3 thus obtained are set in a mold, and the pair of stress cones 4a and 4b and the internal semiconductivity are set. By injecting an insulating rubber such as a silicone rubber material between the bodies 3 to form a main insulator 10a and vulcanizing it, as shown in FIG. 1, the main insulator 10a, the internal semiconductor 3 and a pair of The stress cones 4a and 4b are integrated. In addition, the inner peripheral surfaces of the thick portions 12a and 12b are integrated with the outer peripheral surfaces of the metal fittings 2a and 2b through the adhesives 7a and 7b.

  The rubber unit Ua thus obtained has a diameter difference of about 1.5 to 2.0 mm with respect to the outer diameter of the cable insulators 81a and 81b as the mounted portions. In the figure, reference numeral 5 denotes an external semiconductor composed of a semiconductive paint coating layer provided on the outer periphery of the main insulator 10a.

  According to the rubber unit Ua having such a configuration, as will be described later, a large clamping force can be generated in the vicinity of the mounting portion of the stress cones 4a and 4b with the cable insulators 81a and 81b. The surface pressure can be intensively applied to the portion of the rising portion 4b where the electric field strength is high, and the surface pressure distribution can be matched to the electric field strength distribution as much as possible. By designing the rubber unit Ua of about 0.0 mm), it is possible to reduce the tightening force of the entire rubber unit Ua.

  FIG. 3 shows a partial cross-sectional view of an intermediate connection portion of a 110-132 kV class high voltage CV cable using the rubber unit Ua of the present invention. In the figure, parts common to those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In FIG. 3, the intermediate connection part of the high voltage CV cable as the cable connection part of the present invention is formed as follows. First, a pair of high-voltage CV cables to be connected are stepped to expose cable insulators 81a and 81b and cable conductors (not shown). Then, the exposed cable conductor is connected by the conductor connector 82 to obtain the conductor connecting portion 83 of the high-voltage CV cable. Therefore, the rubber unit Ua according to the present invention that has been fitted and inserted in advance on one of the cable insulators 81a and 81b is brought into a normal position, that is, the contact in which the central portion of the rubber unit Ua corresponds to the central portion of the conductor connecting portion 83. Slide to the desired position. As a result, the rubber unit Ua before assembly shown in FIG. 4A is mounted on the outer periphery of the cable insulators 81a and 81b as shown in FIG. As a result, a tightening force is generated toward the central direction as a whole. In this case, since the end of the rubber unit Ua according to the present invention is constrained by the metal fittings 2a and 2b, the insulating cylinder 1a constituting the rubber unit Ua is formed by mounting the rubber unit Ua with a diameter increased at a normal position. Is constrained by the bonding portions with the metal fittings 2a and 2b, and the non-bonding portions on the inner peripheral surfaces of the inner extensions 43a and 43b of the stress cones 4a and 4b are the outer circumferences of the first cylindrical portions 21a and 21b of the metal fittings 2a and 2b. The diameter is increased radially outward from the surface. As a result, as indicated by an arrow Y2, a large tightening force is generated in the vicinity of the mounting portion of the stress cones 4a and 4b with the cable insulators 81a and 81b, and the electric field strength at the rising portion of the stress cones 4a and 4b is high. As shown in FIG. 5, an intermediate connection portion of the high-pressure CV cable in which the surface pressure is controlled is obtained.

  FIG. 5 shows an ideal surface pressure design pattern of the rubber unit Ua. In the figure, the left vertical axis represents the electric field (kV / mm), the right vertical axis represents the surface pressure, the horizontal axis represents the position at the interface between the insulating cylinder 1a and the cable insulator 81b, the solid line represents the electric field strength distribution, and the broken line represents the surface. The pressure distribution is shown.

  As shown in the figure, the electric field strength at the interface between the insulating cylinder 1a and the cable insulator 81b is highest at the rising portion of the stress cone 4b, and it is ideal that the surface pressure distribution matches the electric field strength distribution as much as possible. The surface pressure of the rubber unit Ua can be reduced by adopting such a surface pressure design.

  As described above, according to the intermediate connection portion of the high-pressure CV cable using the rubber unit Ua according to the present invention, first, the surface pressure distribution matches the electric field strength distribution as much as possible, and the entire rubber unit Ua By using the rubber unit Ua with a small tightening force, that is, by using the rubber unit Ua designed with a small diameter difference (about 1.5 to 2.0 mm), the rubber unit Ua is slid. The so-called self-compression type slide type can be used to ensure stable insulation. Secondly, the rubber unit Ua designed with a small diameter difference can be slid to easily insert the rubber unit Ua into the cable insulator 81b. Third, since the intermediate connection portion of the high-pressure CV cable can be assembled by a self-compression slide type, a diameter-enlarged holding member such as a spiral core is not necessary, and the cost can be reduced.

  FIG. 6 is a longitudinal sectional view of a rubber unit of the present invention suitable for a terminal connection part of a 220 kV class high voltage CV cable. In the figure, parts common to those in FIGS. 1 to 3 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In FIG. 6, the rubber unit Ub of the present invention includes an insulating cylinder 1b formed of an elastic material, for example, a silicone rubber material, and a low-pressure side end (lower part in the figure) of the insulating cylinder 1b that is integrated with the insulating cylinder 1b. And a cylindrical metal fitting 2c.

The insulating cylinder 1b includes a cylindrical main insulator 10b. A cylindrical outer extension 11c extending toward the metal fitting 2c is mainly provided on the outer peripheral edge of the low-pressure side end of the main insulator 10b. It is connected to the insulator 10b concentrically. An annular thick portion 12c is provided on the inner peripheral surface side of the end portion of the outer extension portion 11c so that the inner peripheral surface thereof can be attached to the outer peripheral surface of the metal fitting 2c described later. Here, the outer peripheral surface of the cylindrical main insulator 10b and the outer peripheral surface of the cylindrical outer extension portion 11c are formed to be flush with each other, and the inner peripheral surface of the annular thick portion 12c will be described later. It is formed to be flush with the inner peripheral surface of the inner extension 43c of the stress cone 4c.
On the other hand, the outer periphery of the high-pressure side end (upper part in the drawing) of the main insulator 10b as the insulating cylinder 1b is provided with a cone-shaped outer surface 13c that gradually decreases in diameter toward the high-pressure side end. At the inner peripheral edge of the high-pressure side end, a tulip-shaped recess 14c having an inner surface that gradually increases in diameter from the vicinity of the high-pressure side end toward the high-pressure side end is a main insulator 10b as an insulating cylinder 1b. And is concentric.

  A stress cone 4c made of a cylindrical semiconductive elastic material, for example, a semiconductive silicone rubber material, is integrally embedded concentrically with the main insulator 10b on the inner peripheral surface of the low voltage side end portion of the main insulator 10b. Has been. Here, the inner peripheral surface of the stress cone 4c is formed to be flush with the inner peripheral surface of the main insulator 10b.

  The stress cone 4c has an electric field relaxation portion 41c having a tapered inner peripheral surface that expands in a trumpet shape toward the outer periphery of the central portion of the main insulator 10b, and a thick cylindrical portion 42c on the side facing the metal fitting 2c. An annular inner extension 43c that can be attached to the outer peripheral surface of the metal fitting 2c is provided on the side of the cylindrical portion 42c that faces the metal fitting 2c. An annular protrusion 44c is provided on the inner periphery of the end of the inner extension 43c on the side facing the metal fitting 2c. Here, the length of the outer extension portion 11c in the axial direction is about twice the length of the inner extension portion 43c in the axial direction.

  The metal fitting 2c is formed of aluminum or the like, and a first cylinder portion 21c for attaching the inner peripheral surface of the inner extension portion 43c of the stress cone 4c and a second cylinder for attaching the inner peripheral surface of the outer extension portion 11c. The second cylindrical portion 22c is concentrically connected to the first cylindrical portion 21c at the end opposite to the end facing the stress cone 4c of the first cylindrical portion 21c. ing. Further, a flange portion 26 is continuously provided outwardly in the radial direction at the end portion of the second cylindrical portion 22c opposite to the end portion facing the stress cone 4c. Furthermore, an annular groove 23c is provided on the outer peripheral surface of the first cylindrical portion 21c in the vicinity of the second cylindrical portion 22c. Note that the inner diameter of the metal fitting 2c is larger than the outer diameter of the cable insulator 81c, which will be described later, and the outer diameter of the portion to be attached to the insulating cylinder 1b of the metal fitting 2c is the inner diameter of the inner extension 43c of the stress cone 4c and the main insulation. The inner diameter of the thick portion 12c of the body 10b is substantially the same.

  The main insulator 10b, the stress cone 4c, and the metal fitting 2c as the insulating cylinder 1b having such a configuration are integrated in the same manner as in the first embodiment.

  As described above, the rubber unit Ub of the present invention has the following effects.

  First, similar to the first embodiment, a large clamping force can be generated in the vicinity of the attachment portion of the stress cone 4c to the cable insulator 81c, and the electric field strength at the rising portion of the stress cone 4c is high. A rubber unit Ub having a small diameter difference (about 1.5 to 2.0 mm) can be designed by making it possible to apply a surface pressure intensively to the surface and to make the surface pressure distribution match the electric field strength distribution as much as possible. By doing so, it is possible to reduce the tightening force of the entire rubber unit Ub.

  Secondly, a tulip-shaped recess 14c is provided on the inner peripheral edge of the high-pressure end of the main insulator 10b as the insulating cylinder 1b, so that the high-pressure side of the main insulator 10b as the insulating cylinder 1b is provided. Electric field concentration at the triple junction (triple junction) P of the insulating fluid 98 (see FIG. 7), the main insulator 10b as the insulating cylinder 1b, and the cable insulator 81c (see FIG. 7) at the end can be prevented.

  FIG. 7 is a partial cross-sectional view of a terminal connection portion of a 220 kV class high voltage CV cable using the rubber unit Ub of the present invention. In the figure, parts common to those in FIG. 6 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In FIG. 7, in this embodiment, the cable terminal portion 9 where the cable insulator 81c is exposed by the stripping process, and the soot tube 92 that surrounds the cable terminal portion 9 and has a lower metal fitting 91 disposed under the cable terminal portion 9 itself. And a rubber unit Ub, and a cylindrical adapter 93 disposed between the lower metal fitting 91 and the rubber unit Ub and having flange portions 93a and 93b on the high-pressure side and the low-pressure side.

  The rubber unit Ub having such a configuration is mounted on the outer periphery of the cable insulator 81c with the metal fitting 2c constituting the rubber unit Ub facing the cylindrical adapter 93, and the metal fitting 2c includes the fixing metal 94 and the O-ring 95. And is fixed to a flange portion 93 a on the high pressure side of the adapter 93.

  The rubber unit Ub having such a configuration is assembled as a terminal connection portion of a high-voltage CV cable as follows.

  First, an annular lower metal fitting 91 is fixed in the vicinity of the end of a cable sheath (not shown) of the cable terminal portion 9 via a support lever 97 or the like. Next, the rubber unit Ub is attached to the outer periphery of the cable insulator 81c from its upper end. In this case, the metal fitting 2c of the rubber unit Ub is mounted toward the adapter 93 side, the lower surface of the metal fitting 2c is brought into contact with the upper surface of the flange portion 93a on the high pressure side of the adapter 93 via the O-ring 95, and the fixing metal fitting 94 is attached. The metal fitting 2c is fixed to the flange portion 93a by covering the upper surface of the flange portion 93a of the metal fitting 2c and fixing the adapter 93 and the fixing metal piece 94 with bolts. Thereby, a seal part (oil stop part) is formed.

  Next, the cable terminal portion 9 is surrounded by the soot tube 92, the low-pressure side end portion is placed on the lower metal fitting 91, and both are fixed with bolts. Insulation of silicone oil, mineral oil, synthetic oil, etc. in the soot tube 92 Fill with fluid 98. Thereby, the electrical insulation performance of the space in the soot pipe 92 is ensured. Next, an upper metal fitting (not shown) is attached to the upper portion of the tub tube 92, and an anticorrosion layer (not shown) is formed on the low voltage side end of the cable terminal portion 9, thereby completing the assembly of the terminal connection portion of the high voltage CV cable. .

  As described above, according to the terminal connection part of the high-voltage CV cable using the rubber unit Ub of the present invention, the following effects are obtained.

  First, as in the second embodiment, by using the rubber unit Ub in which the surface pressure distribution is matched to the electric field strength distribution as much as possible and the tightening force of the entire rubber unit Ub is reduced, that is, By using the rubber unit Ub designed with a small diameter difference (about 1.5 to 2.0 mm), it is possible to ensure stable insulation even in a so-called self-compression slide type in which the rubber unit Ub is slid. .

  Second, the rubber unit Ub can be easily inserted into the cable insulator 81c by sliding and moving the rubber unit Ub designed with a small diameter difference.

  Third, since the terminal connection portion of the high-pressure CV cable can be assembled by a self-compression slide type, a diameter-enlarged holding member such as a spiral core is not necessary, and the cost can be reduced.

  Fourth, the fitting 2c of the rubber unit Ub is mounted toward the lower fitting 91, and the fitting 2c is fixed to the flange 93a on the high-pressure side of the adapter 93 via the O-ring 95, so that the conventional seal portion The number of parts can be reduced as compared with the (oil stopper), and the sealing performance of the seal portion (oil stopper) can be greatly improved.

  Fifth, since there is no need to use metal fittings and tape seals dedicated to oil stoppers as in the past, and no need for operator skills, there is no variation in airtightness at the seal part, and assembly is simplified. Can be achieved.

  Sixth, the seal structure by the O-ring 95 can greatly improve the reliability of the seal portion.

  In this embodiment, the metal fitting 2c of the rubber unit Ub is fixed to the adapter 93 via the O-ring 95. However, without using the adapter 93, the metal fitting 2c of the rubber unit Ub via the O-ring 95 is used. You may fix to the lower metal fitting 91.

  FIG. 8 is an exploded cross-sectional view of a rubber unit according to another embodiment of the present invention. In the figure, the same reference numerals are given to portions common to FIGS. 2 and 6, and detailed description thereof is omitted.

  8, in this embodiment, instead of the stress cones 4a, 4b, and 4c having the protrusions 44a, 44b, and 44c shown in FIGS. 2 and 6, the inner peripheral surfaces of the inner extensions 43d and 43e are annular. Stress cones 4d and 4e provided with concave grooves 44d and 44e are used. Instead of the metal fittings 2a, 2b and 2c having the concave grooves 23a, 23b and 23c shown in FIGS. Metal fittings 2d and 2e provided with portions 23d and 23e are used.

  Thus, the first cylindrical portions 21a and 21b of the metal fittings 2d and 2e in which the semiconductive adhesives 6a and 6b are applied only to the protrusions 23d and 23e by the same method as in the first embodiment are shown in FIG. As shown in FIG. 8 (c), the inner extensions excluding the concave grooves 44d and 44e of the stress cones 4d and 4e can be mounted in the inner extensions 43d and 43e of the stress cones 4d and 4e shown in FIG. The inner peripheral surfaces of 43d and 43e can be attached to the outer peripheral surfaces of the first cylindrical portions 21a and 21b excluding the projections 23d and 23e of the metal fittings 2d and 2e in an unbonded state. The projections 23d and 23e of 2e are fitted into the concave grooves 44d and 44e of the stress cones 4d and 4e, and only the concave grooves 44d and 44e of the stress cones 4d and 4e are more firmly attached to the metal fittings 2d and 2e. By be integrated with an adhesive state, stress cone 4d, 4e, the end portion side of the inner circumferential only the brackets 2d, to 2e, is more firmly fixed, it is possible to prevent separation from the bracket 2d, 2e.

  The stress cones 4d and 4e with the pair of metal fittings 2d and 2e, the main insulator 10a (see FIG. 1), and the internal semiconductor 3 (see FIG. 1) having the above-described configuration are the same as those in the first embodiment. Is integrated.

  Also in this embodiment, as in the first embodiment, a large tightening force is generated in the vicinity of the mounting portion of the stress cones 4d and 4e with the cable insulators 81a (see FIG. 3) and 81b (see FIG. 3). The surface pressure can be applied intensively to the high electric field strength portions of the rising portions of the stress cones 4d and 4e, and the surface pressure distribution can be matched to the electric field strength distribution as much as possible. By designing a rubber unit having a diameter difference (about 1.5 to 2.0 mm), the tightening force of the entire rubber unit can be reduced.

  In the third and fourth embodiments, similarly, the stress cone 4c can be configured as a rubber unit in which an annular concave groove is provided, and the metal fitting 2c is provided with an annular protrusion. Is obtained.

  FIG. 9 is an exploded cross-sectional view of a rubber unit according to another embodiment of the present invention. In the figure, the same reference numerals are given to portions common to FIGS. 2 and 6, and detailed description thereof is omitted.

  9, in this embodiment, instead of the stress cones 4a, 4b, and 4c having the protrusions 44a, 44b, and 44c shown in FIGS. 2 and 6, the inner peripheral surfaces of the inner extensions 43f and 43g are smooth. That is, the stress cones 4f and 4g in which no protrusions or grooves are formed on the inner peripheral surfaces of the inner extensions 43f and 43g are used, and the metal fitting 2a having the grooves 23a, 23b, and 23c shown in FIGS. Instead of 2b and 2c, metal fittings 2f and 2g having a smooth outer peripheral surface, that is, having no concave grooves or protrusions on the outer peripheral surface, are used.

  Thus, by the same method as in the first embodiment, the semiconductive adhesive is applied only to the outer peripheral surface at a predetermined location (the outer peripheral surface at the position corresponding to the concave grooves 23a, 23b, and 23c shown in FIGS. 2 and 6). The first cylindrical portions 21a and 21b of the metal fittings 2f and 2g coated with the agents 6a and 6b are mounted in the inner extensions 43f and 43g of the stress cones 4f and 4g shown in FIG. As shown in c), the inner peripheral surfaces of the inner extensions 43f and 43g excluding the predetermined portions of the stress cones 4f and 4g (positions corresponding to the protrusions 44a, 44b and 44c shown in FIGS. 2 and 6) are the fittings 2d. 2e can be attached to the outer peripheral surfaces of the first cylindrical portions 21a and 21b excluding a predetermined portion in an unbonded state, and only predetermined portions of the stress cones 4f and 4g are bonded to the metal fittings 2f and 2g. By integrating in the state Stress cone 4f, 4g of the end portion of the inner circumferential only the brackets 2f, is secured to 2g, it is possible to prevent separation from the bracket 2f, 2 g.

  The pair of fittings 2f, 2g with stress cones 4f, 4g, the main insulator 10a (see FIG. 1) and the internal semiconductor 3 (see FIG. 1) having the above-described configuration are the same as those in the first embodiment. Is integrated.

  Also in this embodiment, as in the first embodiment, a large tightening force is generated in the vicinity of the mounting portion between the stress cones 4f and 4g and the cable insulators 81a (see FIG. 3) and 81b (see FIG. 3). The surface pressure can be applied intensively to the high electric field strength portions of the rising portions of the stress cones 4f and 4g, and the surface pressure distribution can be matched to the electric field strength distribution as much as possible. By designing a rubber unit having a diameter difference (about 1.5 to 2.0 mm), the tightening force of the entire rubber unit can be reduced.

  Moreover, also in Examples 3 and 4, it can be set as the structure of the rubber unit in which the one adhesive part of the 1st cylindrical part 21c and the stress cone 4c is smooth, and the effect similar to the said Example is acquired. .

  In the above-described embodiments, the present invention is described with specific embodiments shown in the drawings. However, the present invention is not limited to these embodiments, and as long as the effects of the present invention are exhibited, You may comprise as follows.

  First, in the above-described embodiment, the outer extensions 11a, 11b, and 11c are formed of an insulating elastic material, but are formed of a semiconductive elastic material similar to the stress cones 4a, 4b, and 4c. May be. That is, as shown in FIG. 10, the cylindrical stress cone 4h is provided at the end facing the metal fittings 2a, 2b, 2c of the insulating cylinders 1a, 1b, and the outer peripheral surface of the cylindrical cylinder is itself the outer peripheral surface of the insulating cylinders 1a, 1b. An annular ring that can be embedded concentrically with the insulating cylinders 1a and 1b so as to be attached to the outer peripheral surface of the metal fittings 2a, 2b, and 2c at the end of the stress cone 4h facing the metal fittings 2a, 2b, and 2c. The inner peripheral surface located on the end side opposite to the end facing the stress cone 4h among the inner peripheral surfaces of these concave portions is the second cylindrical portion 22a, 22b, 22c. The inner peripheral surface which is integrally bonded to the outer peripheral surface and is located on the end side facing the stress cone 4h of the inner peripheral surface of the recessed portion is a part of the first cylindrical portion 21a, 21b, 21c. Non-adhesive to the outer peripheral surface excluding (projection in Fig. 10) In may be configured to deposit.

  Second, in the above-described embodiment, the stress cones 4a, 4b, and 4c are formed of a semiconductive elastic material. However, the stress cones 4a, 4b, and 4c are formed of an insulating elastic material as shown by a broken line in FIG. Alternatively, semiconductive paint may be applied to the entire peripheral surface of itself or the inner peripheral surface of the inner extensions 43a, 43b, 43c and the entire peripheral surface excluding the end surface 42d facing the metal fittings 2a, 2b, 2c. That is, the cable shielding side and the metal fittings 2a, 2b, and 2c may be electrically connected.

  Thirdly, the metal fitting is not limited to one made of aluminum, and may be made of, for example, copper, copper alloy, or aluminum alloy.

  Fourthly, in the above-described embodiment, the case where the main insulator 10b, the internal semiconductor 3, and the stress cones 4a, 4b, and 4c are formed of silicone rubber has been described. However, ethylene propylene rubber (EPR) or the like is described. May be formed.

  Fifth, in this embodiment, the outer diameters of the first cylindrical portions 21a, 21b, and 21c and the second cylindrical portions 22a, 22b, and 22c are the same, but the first cylindrical portions 21a, The outer diameters of 21b and 21c may be different from the outer diameters of the second cylindrical portions 22a, 22b and 22c.

Sixth, the case where the insulating oil is filled in the soot tube 92 has been described in the above-described embodiment, but an insulating gas such as SF ₆ gas may be filled instead of the insulating oil.

  Seventh, in the above-described embodiment, the case where the present invention is applied to an air termination connection portion has been described. However, the present invention may be applied to a gas termination connection portion or an oil termination connection portion.

  Eighth, in the above-described embodiments, the intermediate connection portion having the applied voltage of 110 to 132 kV class and the air termination connection portion having the 220 kV class are described, but the present invention is not limited to these voltages.

Ua, Ub ... rubber units 1a, 1b ... insulating cylinders 4a, 4b, 4c ... stress cones 11a, 11b, 11c ... outer extension parts 21a, 21b, 21c ... first cylindrical part 22a, 22b, 22c ... 2nd cylindrical part 23a, 23b, 23c ... Groove 26 ... Flange part 43a, 43b, 43c ... Inner extension part 44a, 44b, 44c ... Projection part 81a, 81b, 81c ... Cable insulator 83 ... Conductor connection part 9 ... Cable terminal part 91 ... Lower metal fitting 92 ... Steel pipe 93 ... Adapter 95 ... O-ring

Claims (8)

An insulating cylinder made of an elastic material, and a cylindrical metal fitting provided concentrically with the insulating cylinder at at least one end of the insulating cylinder;
A cylindrical stress cone is embedded concentrically with the insulating cylinder on the inner periphery of the end of the insulating cylinder facing the metal fitting,
The metal fitting is connected to a first cylindrical portion and a second cylindrical portion concentrically connected to the first cylindrical portion at an end opposite to the end of the first cylindrical portion facing the stress cone. With a cylindrical part,
A cylindrical outer side that extends toward the second cylindrical part at the end of the insulating cylinder facing the metal fitting and whose inner peripheral surface can adhere to the outer peripheral surface of the second cylindrical part An extension is provided,
A cylindrical inner side that extends toward the first cylindrical portion at the end of the stress cone facing the metal fitting and whose inner peripheral surface can adhere to the outer peripheral surface of the first cylindrical portion. An extension is provided,
The inner peripheral surface of the outer extension is integrally bonded to the outer peripheral surface of the second cylindrical portion,
The rubber unit is characterized in that an inner peripheral surface of the inner extension portion is attached in an unbonded state to an outer peripheral surface of the first cylindrical portion. An insulating cylinder made of an elastic material, and a cylindrical metal fitting provided concentrically with the insulating cylinder at at least one end of the insulating cylinder;
A cylindrical stress cone is embedded concentrically with the insulating cylinder at the end of the insulating cylinder facing the metal fitting,
The metal fitting is connected to a first cylindrical portion and a second cylindrical portion concentrically connected to the first cylindrical portion at an end opposite to the end of the first cylindrical portion facing the stress cone. With a cylindrical part,
An end of the stress cone facing the metal fitting is provided with an annular recess that can be attached to the outer peripheral surface of the metal fitting,
Of the inner peripheral surface of the recessed portion, the inner peripheral surface located on the end side opposite to the end facing the stress cone is integrally bonded to the outer peripheral surface of the second cylindrical portion,
Of the inner peripheral surface of the recessed portion, an inner peripheral surface located on an end side facing the stress cone is attached to the outer peripheral surface of the first cylindrical portion in an unbonded state. Rubber unit to be used.   An annular groove or protrusion is provided on the outer peripheral surface of the first cylinder near the second cylinder, and the groove or protrusion is provided on the inner periphery of the inner extension of the stress cone. The rubber unit according to claim 1, wherein an annular protrusion or a concave groove that can be fitted to the groove is provided.   An annular concave groove or protrusion is provided on the outer peripheral surface of the first cylindrical part in the vicinity of the second cylindrical part, and the concave groove or the protrusion is provided on the inner periphery of the concave part of the stress cone. The rubber unit according to claim 2, wherein an annular protrusion or a concave groove that can be fitted is provided.   The flange part is continuously provided in the outer-periphery edge part of the edge part on the opposite side to the edge part which opposes the said stress cone of the said metal fitting toward the radial direction outward. 4. The rubber unit according to any one of 4 above. A conductor connecting portion of a power cable formed by connecting cable conductors of a pair of power cables, and a rubber unit according to any one of claims 1 to 5,
The cable connecting portion, wherein the rubber unit is elastically attached to an outer periphery of the conductor connecting portion over an outer periphery of a cable insulator constituting the pair of power cables. 6. The cable terminal part in which the cable insulator is exposed by the stepping process, a soot pipe surrounding the cable terminal part and having a lower metal fitting disposed on the low pressure side of the cable terminal part, 6. With the described rubber unit,
The rubber unit is mounted on the outer periphery of the cable insulator with the metal part constituting the rubber unit facing the lower metal part side,
The cable connection part, wherein the metal fitting is fixed to the lower metal fitting through an O-ring. 6. The cable terminal part in which the cable insulator is exposed by the stepping process, a soot pipe surrounding the cable terminal part and having a lower metal fitting disposed on the low pressure side of the cable terminal part, 6. The rubber unit described above, and a cylindrical adapter that is disposed between the lower metal fitting and the rubber unit and has a flange portion on the high-pressure side,
The rubber unit is mounted on the outer periphery of the cable insulator with the metal fittings constituting the rubber unit facing the adapter side,
A cable connecting portion, wherein the metal fitting is fixed to the flange portion via an O-ring.

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