JP4667303B2 - Normal temperature shrinkable rubber unit - Google Patents

Description

  The present invention relates to a room temperature shrinkable rubber unit used for an insulating connection (IJ) of a power cable such as a high voltage CV cable.

  Various types of structures such as an extrusion mold, a prefabricated mold, a tape winding mold, and a tape winding mold are applied to an insulating connection portion such as a high-voltage CV cable. In addition to these, due to remarkable progress in rubber mold technology in recent years, one-piece joints having excellent workability using one-piece cold-shrinkable rubber units have been developed, and this application is being expanded. As shown in FIG. 2, the cold-shrinkable rubber unit used for this joint includes an internal semiconductive layer 1, a reinforcing insulating layer 3, an external semiconductive layer 5, and a reinforcing insulating layer formed mainly of a rubber material. 3 is provided in the vicinity of one of the stress cone portions 7 and 7 on both ends and the stress cone portion 7 of the reinforcing insulating layer 3 (the stress cone portion 7 on the right side in the illustrated example), and the external semiconductive layer 5 is disposed in the longitudinal direction. The inner semiconductive layer 1, the reinforcing insulating layer 3, the outer semiconductive layer 5, and the stress cone portions 7 and 7 are molded into a substantially cylindrical shape to form a one-piece. Is. The other stress cone portion 7 of the reinforcing insulating layer 3 is integrally connected to the end portion of the external semiconductive layer 7.

  This room temperature shrinkable rubber unit has elasticity, and its inner diameter is smaller than the outer diameter of a cable connection portion (not shown) to which it is attached, and a diameter-expanding member (not shown) that can be disassembled in advance in a factory or the like 1) The diameter is supported on the upper side. When forming a cable insulation connection part using this rubber unit, this is positioned on the cable connection part in the field, and the diameter is reduced by disassembling and removing the diameter-expanding member to be on the cable connection part. This is done by mounting (see Patent Document 1).

JP 2000-324643 A (paragraphs 0018 to 0025 and FIGS. 1 to 4 in the detailed description of the invention)

  However, in the conventional cold shrinkable rubber unit, the edge cut portion 9 is provided in the vicinity of one stress cone portion 7 (the stress cone portion 7 on the right side in the illustrated example) where the stress of the outer semiconductive layer 5 is lowest. The shape of the external semiconductive layer 5 formed on the outer peripheral surface of the reinforcing insulating layer 3 becomes thin on the edge cut portion 9 side and becomes thick on the other stress cone portion 7 side and becomes complicated.

  Therefore, when a semiconductive rubber material is injected into the mold and the outer semiconductive layer 5 is molded on the outer peripheral surface of the reinforcing insulating layer 3, the speed of the rubber material flowing in the mold is uneven (unbalanced). In other words, the rubber material flow becomes worse, the control of the molding pressure of the rubber material becomes complicated, the molding of the outer semiconductive layer 5 becomes troublesome, and the thickness of the outer semiconductive layer 5 becomes thicker. May fluctuate. Moreover, since the other stress cone part 7 side of the external semiconductive layer 5 becomes thicker and harder to cure than the edge cut part 9 side, the time required for curing the external semiconductive layer 5 becomes longer. Therefore, there are problems that the manufacturing cost of the rubber unit is increased and the quality is lowered.

  The present invention has been made in view of the above problems, and the formation of the external semiconductive layer is easy and the time required for the formation is shortened. An object of the present invention is to provide a good quality cold shrinkable rubber unit that is inexpensive to manufacture.

In order to achieve the above object, the present invention integrates an internal semiconductive layer formed mainly of a rubber material, a reinforcing insulating layer, an external semiconductive layer, and a stress cone portion, and the internal semiconductive layer is formed by integrating the internal semiconductive layer. The layer is provided on the inner peripheral surface of the central portion of the reinforcing insulating layer, the stress cone portion is provided on both inner peripheral sides of the reinforcing insulating layer, and the outer semiconductive layer is provided on the outer peripheral surface of the reinforcing insulating layer. It is a cylindrical cold shrinkable rubber unit,
Furthermore, the inner diameter of the cable connecting portion to be mounted is smaller than the outer diameter, and after being arranged on the cable connecting portion in a state where the diameter is supported on the diameter expanding member that can be disassembled, the diameter expanding member is disassembled. It is a normal temperature shrinkable rubber unit that is reduced in diameter by being removed and attached to the cable connection part,
An edge cutting part that cuts off the stress cone part and the outer semiconductive layer is provided by exposing the outer peripheral surface of the reinforcing insulating layer in the vicinity of both stress cone parts to both ends,
The outer peripheral surface of the reinforcing insulating layer extends in parallel to the axial direction of the room temperature shrinkable rubber unit from the outer semiconductive layer end side in these both edge cut portions ,
In addition, the end of the stress cone portion protrudes from both ends of the reinforcing insulating layer .

  As described above, the edge cut portion is provided in the vicinity of both stress cone portions of the external semiconductive layer, so that the external semiconductive layer is formed in a thin and uniform thickness on the outer peripheral surface of the reinforcing insulating layer. Thus, the shape of the outer semiconductive layer is simplified. As a result, when the semiconductive rubber material is injected into the mold and the external semiconductive layer is molded on the outer peripheral surface of the reinforcing insulating layer, the speed of the rubber material flowing in the mold becomes substantially uniform, and the rubber The flow of the material does not stagnate in the mold, the rubber material flows smoothly in the mold, the control of the molding pressure of the rubber material is simplified, and the formation of the external semiconductive layer is facilitated In addition, the thickness of the outer semiconductive layer is less likely to vary.

  In addition, since the outer semiconductive layer is thin and simplified in shape, the outer semiconductive layer is uniformly and quickly cured over the entire periphery, and the time required for curing the outer semiconductive layer is shortened. Therefore, it is possible to manufacture the cold-shrinkable rubber unit with a short delivery time, thereby reducing the manufacturing cost and improving the quality.

  The cold-shrinkable rubber unit used to insulate and connect the power cable may be specified by the user in accordance with the line conditions, etc., as in the present invention. By using the cold-shrinkable rubber unit provided in the vicinity of both stress cone parts, there is no need to prepare a new cold-shrinkable rubber unit that meets the user's specifications, saving labor and insulating connection parts. The workability of formation can be improved.

  Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing the configuration of a cold-shrinkable rubber unit according to the present invention. In addition, the same code | symbol is attached | subjected to the thing of the same structure as the cold shrinkable rubber unit of a prior art.

  The cold-shrinkable rubber unit according to this embodiment includes an internal semiconductive layer 1 formed mainly of a rubber material such as ethylene propylene rubber (EPR) and silicone rubber (SR), a reinforcing insulating layer 3, and an external semiconductive layer. 11, the stress cone portions 7 and 7 on both ends of the reinforcing insulating layer 3, and the stress cone portions 7 and 7 on both sides of the external semiconductive layer 11. Parts 7 and 7 and edge cutting parts 9 and 9 which are longitudinally cut, and the inner semiconductive layer 1, the reinforcing insulating layer 3, the outer semiconductive layer 11 and the stress cone parts 7 and 7 are molded into a substantially cylindrical shape. It is formed into one piece.

  More specifically, the reinforcing insulating layer 3 is formed in a substantially cylindrical shape by molding the rubber material. The inner semiconductive layer 1 is embedded in the inner peripheral surface of the central portion of the reinforcing insulating layer 3 by molding a semiconductive rubber material mixed with carbon or the like so that the inner peripheral surface is exposed, and is cylindrical. It is formed in a shape. The outer semiconductive layer 11 is formed into a thin cylindrical shape by molding a semiconductive rubber material mixed with carbon or the like on the outer peripheral surface of the reinforcing insulating layer 3. Both stress cone portions 7 and 7 are formed in a substantially cylindrical shape by molding a semiconductive rubber material mixed with carbon or the like so as to be positioned at both ends of the reinforcing insulating layer 3. Both edge cut portions 9, 9 are provided on the outer peripheral surface of the reinforcing insulating layer 3 in the vicinity of both stress cone 7 portions 7, 7 of the outer semiconductive layer 11 so as to be edge-cut with the stress cone portions 7, 7 in the longitudinal direction. .

  As a result, the shape of the outer semiconductive layer 11 is simplified with a thin and uniform thickness, the control of the molding pressure of the rubber material is simplified, and the formation of the outer semiconductive layer 11 is facilitated. In addition, the thickness of the outer semiconductive layer 11 is less likely to vary. Further, the time required for curing the outer semiconductive layer 11 is shortened.

  This room temperature shrinkable rubber unit has elasticity, and its inner diameter is smaller than the outer diameter of a cable connection portion (not shown) to which it is attached, and a diameter-expanding member (not shown) that can be disassembled in advance in a factory or the like. 1) The diameter is supported on the upper side. When forming a cable insulation connection part using this rubber unit, this is positioned on the cable connection part in the field, and the diameter is reduced by disassembling and removing the diameter-expanding member to be on the cable connection part. It is done by wearing. The fitting surface pressure when the rubber unit is attached to the cable connection portion is secured by the elasticity generated by expanding the diameter of the rubber unit.

  There are various methods for manufacturing the cold-shrinkable rubber unit. For example, the internal semiconductive layer 1 and the stress cone portions 7 and 7 are each made up of a dedicated die and a mandrel (mandrel). ) And molding by molding.

Next, the internal semiconductive layer 1 and the stress cone portions 7 and 7 are arranged at the center on the core metal forming the reinforcing insulating layer 3, and the stress cone portions 7 and 7 are spaced apart from each other at a predetermined interval. The cored bar is held in the mold for forming the reinforcing insulating layer, and the reinforcing insulating layer 3 is molded so as to cover the internal semiconductive layer 1 and the stress cone portions 7 and 7. Formed by molding.

Next, after replacing the rubber unit core having the reinforcing insulating layer 3 formed on the outer peripheral surface with the core metal, or replacing the core metal with a core metal for forming an external semiconductive layer, The external semiconductive layer 11 is molded so as to be held in a mold for forming the external semiconductive layer, and on the outer peripheral surface of the reinforcing insulating layer 3, the edge cut portions 9 and 9 are provided in the vicinity of the stress cone portion 77. Form. At this time, the semiconductive rubber material for forming the outer semiconductive layer 11 does not flow into the stress cone portions 7 and 7 and is not covered on the outer peripheral surface of the stress cone portions 7 and 7. For example, as indicated by a one-dot chain line in FIG. 1, it is desirable to provide an annular stopper member 15 that protrudes inward at a portion where the edge cut portion 9 of the mold 13 is provided.

  As described above, the present invention includes an internal semiconductive layer formed mainly of a rubber material, a reinforcing insulating layer, an external semiconductive layer, stress cone portions on both ends of the reinforcing insulating layer, and an external semiconductive layer. A cylindrical cold-shrinkable rubber unit provided in the vicinity of the stress cone portion of the layer and provided with an edge cut portion for cutting the outer semiconductive layer in the longitudinal direction. Therefore, the outer semiconductive layer is formed in a cylindrical shape with a thin and uniform thickness on the outer peripheral surface of the reinforcing insulating layer, and the shape of the outer semiconductive layer is simplified.

As a result, when the semiconductive rubber material is injected into the mold and the external semiconductive layer is molded on the outer peripheral surface of the reinforcing insulating layer, the speed of the rubber material flowing in the mold becomes substantially uniform, and the rubber The flow of the material does not stagnate in the mold, the rubber material flows smoothly in the mold, the control of the molding pressure of the rubber material is simplified, and the formation of the external semiconductive layer is facilitated In addition, the thickness of the outer semiconductive layer is less likely to vary.

  In addition, since the outer semiconductive layer is thin and simplified in shape, the outer semiconductive layer is uniformly and quickly cured over the entire periphery, and the time required for curing the outer semiconductive layer is shortened. Therefore, it is possible to manufacture the cold-shrinkable rubber unit with a short delivery time, thereby reducing the manufacturing cost and improving the quality.

  Further, the cold-shrinkable rubber unit used to insulate and connect power cables of different diameters may be designated by the user depending on the line conditions, etc., as in the present invention. By using a cold-shrinkable rubber unit that is provided near both stress cones of the outer semiconductive layer, there is no need to prepare a new cold-shrinkable rubber unit that meets the user's specifications, saving labor. Thus, the workability of forming the insulating connection portion can be improved.

It is sectional drawing which shows the structure of the normal temperature shrink type | mold rubber unit of this invention. It is sectional drawing which shows the structure of the conventional cold shrinkable rubber unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Internal semiconductive layer 3 Reinforcement insulating layer 5 External semiconductive layer 7 Stress cone part 9 Edge cut part 11 External semiconductive layer 13 Mold 15 Annular stopper member

Claims (1)

An internal semiconductive layer formed mainly of a rubber material, a reinforcing insulating layer, an external semiconductive layer, and a stress cone portion are integrated, and the internal semiconductive layer is an inner peripheral surface of a central portion of the reinforcing insulating layer. The stress cone portion is provided on the inner peripheral side of both ends of the reinforcing insulating layer, and the outer semiconductive layer is a cylindrical room temperature shrinkable rubber unit provided on the outer peripheral surface of the reinforcing insulating layer,
Furthermore, the inner diameter of the cable connecting portion to be mounted is smaller than the outer diameter, and after being arranged on the cable connecting portion in a state where the diameter is supported on the diameter expanding member that can be disassembled, the diameter expanding member is disassembled. It is a normal temperature shrinkable rubber unit that is reduced in diameter by being removed and attached to the cable connection part,
An edge cutting part that cuts off the stress cone part and the outer semiconductive layer is provided by exposing the outer peripheral surface of the reinforcing insulating layer in the vicinity of both stress cone parts to both ends,
The outer peripheral surface of the reinforcing insulating layer extends in parallel to the axial direction of the room temperature shrinkable rubber unit from the outer semiconductive layer end side in these both edge cut portions ,
In addition, the normal temperature shrinkable rubber unit is characterized in that the ends of the stress cone portions protrude from both ends of the reinforcing insulating layer .

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