JP3400031B2 - Core for manufacturing reinforced insulator - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connection processing unit in which a spindle-shaped insulator molded in advance is arranged on a conductor connection portion of a rubber / plastic power cable. In particular, a core used for molding the reinforcing insulator can be easily removed, and a cooling means is provided on the core so that the core can be cooled from the inside of the reinforcing insulator. The present invention relates to a core for manufacturing a reinforced insulator. 2. Description of the Related Art In a high-voltage power cable such as a cross-linked polyethylene insulated power cable or the like, an insulating material such as plastic is formed in a cone shape on an outer peripheral portion of an intermediate connection portion by means of extrusion molding or the like. That is being done.
However, extruding a plastic material to form an insulating part requires carrying out an extrusion molding device to the cable connection work site and performing the work.Therefore, providing a clean room at the work site or carrying in the extrusion molding device is required. In addition to the problem that the preparation is troublesome, there is a problem that the operation of molding the reinforcing insulator requires a lot of time. In order to solve the above-mentioned problem of molding the reinforcing insulator on site, for example, Japanese Patent Application Laid-Open No.
As disclosed in Japanese Patent Application Laid-Open No. 0721 and Japanese Patent Application Laid-Open No. 4-272677, it has been proposed to configure a means for covering a connection portion of a cable using a reinforcing insulator molded in advance. [0003] Of the above conventional examples, Japanese Patent Laid-Open No.
In Japanese Patent Application Publication No. 1-2003, the reinforcing insulator has a cylindrical outer shape, and a through-hole for locating a connection portion of a cable is formed in a tapered shape in which the outside has a large diameter and the diameter gradually becomes smaller toward the inside. Used. Then, a connection portion of the cable is arranged in the through hole of the reinforcing insulator, and a cone-shaped spacer is inserted from both sides of the tapered portion so that the cable and the reinforcing insulator can be fixed. In the example disclosed in Japanese Patent Application Laid-Open No. 4-272677, a means for combining a reinforcing insulator formed in two pieces in a longitudinal direction is used, and a cable connection is provided inside the reinforcing insulator. A hole corresponding to the shape of the part is formed. Then, heating is performed in a state where the half-shaped reinforcing insulator is attached to the cable connecting portion, and the connecting portion of the half-shaped member of the reinforcing insulator and the periphery of the cable are melted and connected, An integral reinforcing insulator can be formed. [0005] The molding method of the reinforcing insulator as described above is as follows.
Although any means can be used depending on the type and size of the cable, it is considered that a connection processing section (insulated linear connection section) as shown in FIG. . In the connection processing unit 10 shown in FIG. 6, the connection processing unit 10 is configured by arranging a reinforcing insulator 11 on an outer peripheral portion thereof corresponding to a portion where the cables 1 and 1a are connected by the conductor connectors 9 and 9a. are doing. In the connection processing unit 10, a high-voltage shield electrode 13 is disposed at the center of a hole 12 penetrating the center of the reinforcing insulator 11, and the outer peripheral portions of the conductor connectors 9 and 9 a are arranged with respect to the high-voltage shield electrode 13. Are brought into contact with the conductor contacts 8 disposed at the same position. Further, a shielding layer 1 is provided on the outer periphery of the reinforcing insulator 11.
A layer 15 of the waterproofing mixture is formed via 4 and the outside thereof is covered by a protective tube 16, and waterproofing layers 19 and 19a are provided between both ends and the surface of the cable. further,
An insulating tube 17 is arranged on one side of the protection tube 16, and terminal seats 18 are provided on the protection tube 16 to constitute a means for connecting to the cross bond. The cable for forming the connection processing section 10 can be applied to a general high-voltage power transmission CV cable, but in the example shown in the drawing, a CV coated with aluminum corrugated coating is used. It is intended for the cables 1 and 1a. When connecting the cables 1 and 1a, the cables are directly led out to the connection ends of the corresponding cables over a predetermined length, and the outer aluminum pipe 7 and the outer shielding layer 6, The semiconductive layer 5 is removed stepwise so that the insulator layer 4 is exposed by a predetermined length. After that, in a state where the conductors 2 and 2a are exposed for a predetermined length, the ends of the insulator layer 4 are cut into a tapered shape and formed. Attach 9a and prepare for connection. Further, one end of the cable is inserted into the through hole 12 of the reinforcing insulator 11, and the conductor connectors 9 and 9 a are positioned so as to correspond to the high-voltage shield electrode 13 of the reinforcing insulator 11. After that, the other cable is inserted into the reinforcing insulator 11, and the conductor connector 9 a of the other cable is engaged with the conductor connector 9 of the one cable 1, and the inside of the reinforcing insulator 11 is The connection of the cable conductor is made. As described above, in a state where the reinforcing insulator 11 is integrally fixed to the cable connection portion,
And a shield layer 14 is provided around the periphery of the cable, and an end of the shield layer 14 is provided so as to overlap the outer semiconductive layer 5 of the cable. On the outside of the shielding layer 14, a layer 15 of the waterproofing mixture is long applied so as to cover the end of the exterior aluminum pipe,
A protective tube 16 is attached to the outer periphery, and waterproof layers 19 and 19a are applied to the ends. [0008] The reinforcing insulator disposed in the connection processing section uses a means of injecting a plastic material such as cross-linked polyethylene into a casting mold and integrally molding the same. When molding the reinforcing insulator, for example, when using a material obtained by adding dicumyl peroxide as a cross-linking material to polyethylene, the temperature at the time of injecting the plastic material is 80 to 140 ° C, particularly 100 to 100 ° C. It is required to control in the range of 120 ° C. However, when molding the reinforcing insulator by setting the heating temperature as described above,
After the plastic material is injected into the mold and cooled naturally, the reinforcing insulator is cooled from the outside, so the outer resin solidifies and then the inner resin solidifies while being dragged outwards. The resin in contact with the inserted core is also pulled outward. At this time, the core is not uniformly pulled and the circle to be formed by the core is distorted. Also,
There is a problem that the resin adheres to the core surface, making it difficult to remove the core. Therefore, in order to solve the above-mentioned problem, it is conceivable to apply means as disclosed in, for example, Japanese Patent Application Laid-Open No. 5-24056. In the above conventional example, the reinforcing insulator is provided by covering the outer peripheral portion of the core with a plastic member constituting the reinforcing insulator and a heat-shrinkable tube having a property of not being adhered or meltable. The core can be easily pulled out even in a cooled state. However, when the reinforcing insulator has a large thermal shrinkage and is cooled in a state where the core is strongly fastened, there remains a problem that it is difficult to pull out the core from the reinforcing insulator. Further, when the reinforcing insulator is cooled, there is a problem that the diameter of the through-hole provided in a state penetrating through the central portion of the reinforcing insulator becomes small, and since the diameter of the through-hole becomes small, a cable is inserted. In some cases, a drawback such as an obstacle to the connection process may occur, which may hinder the efficiency of the operation for forming the connection processing unit. SUMMARY OF THE INVENTION The object of the present invention is to solve the above-mentioned problems in molding a reinforced insulator. A cooling means is provided for a core, and a plastic material is poured into a casting mold. After injection, by applying a cooling action from the part in contact with the core, the shape of the through hole of the reinforcing insulator can be maintained, and due to the cooling of the plastic material, uneven shrinkage and deformation of the inside of the hole due to cooling of the plastic material It is an object of the present invention to provide a core for producing a reinforced insulator which prevents occurrence of cracks. The present invention relates to a reinforcing insulator used for forming a connection processing part by arranging a spindle-shaped insulator molded in advance on a conductor connecting part of a rubber / plastic power cable, wherein the reinforcing insulating material is used. When the body is molded using a mold, a core forming a through hole corresponding to a cable connection portion is constituted by two cylindrical members connectable at a central portion in a length direction, and two substantially cylindrical members are formed. The member constituted by the tubular body of the core, a large-diameter portion at both ends of the core, a small-diameter connection portion disposed in the center portion, is configured by a tapered portion formed between the large-diameter portion and the connection portion, At the center of the core cylinder, a fixing bolt is arranged to penetrate, and the end of the fixing bolt is fastened by a nut arranged outside the side wall of the end of the large-diameter portion. While setting the shape, at the connection part of the core, The end of the member is configured as a small-diameter cylindrical portion, and the tapered surface of the insertion portion formed at the end of the other member is inserted into the other cylindrical portion to enable the connection portion to be sealed, After the cooling means is connected to the inside of the core and the reinforcing insulator is molded, a cooling action on the reinforcing insulator can be performed from the core portion. As described above, the through holes formed in the reinforcing insulator correspond to the large diameter at both ends and the small diameter at the center, so that two cores capable of separating the core at the center are formed. It is configured by combining members so that the core can be easily removed after the reinforcing insulator is molded. In addition, the connection between the two members constituting the core is formed by inserting the tapered portion of the other member into the cylindrical portion formed at the end of one member, so that the connection between the two members can be improved. It becomes possible to set. Furthermore, by providing the cooling means inside the core, after the reinforcing insulator is molded, a cooling action can be performed from the side of the through hole of the reinforcing insulator, and the plastic material is cooled from the inside. The shape of the through hole can be maintained, and the core can be easily removed. DESCRIPTION OF THE PREFERRED EMBODIMENTS A core for manufacturing a reinforced insulator according to the present invention will be described with reference to the illustrated example. The example shown in FIG. 1 shows a schematic configuration of an apparatus used for molding a reinforcing insulator. A casting mold 20 has a heater 22 for heating a plastic material to be cast. , 22a
Are arranged, and the shape of the internal space 21 is made to match the reinforcing insulator. In addition, a core 25 is disposed at the center of the inner space of the casting mold 20, and the high-voltage shield electrode 13 is positioned and fixed in a state of supporting the high-voltage shield electrode 13 with respect to the small diameter portion at the center of the core. A device for injecting a plastic material from an extruder 24 is connected to an injection port 23 provided in the casting mold 20. Then, for example, polyethylene obtained by adding dicumyl peroxide as a cross-linking material is heated to 100 to 120 ° C., and a molten state is applied to the internal space 21 of the casting mold 20 while applying pressure. The reinforcing insulator is molded so as to fill the space. While injecting a plastic material into the interior space 21 of the casting mold and performing molding of the reinforcing insulator, energization is continued to a heater arranged around the casting mold, The cast plastic material is maintained at a constant temperature so that the molding operation can be performed in good condition. A core 25 inserted into the casting mold and used to form a through hole of the reinforcing insulator is configured as shown in FIG. Core 2 shown in FIG.
5 is a member 2 composed of two substantially cylindrical tubes.
6 and 27, large diameter portions 31 and 31a at both ends of the core 25, a small diameter connection portion 35 disposed at the center portion, and a tapered portion formed between the large diameter portion and the connection portion. 3
3, 33a. At the center of the cylinder of the core 25, a fixing bolt 40 is disposed so as to pass therethrough,
The ends of the fixing bolts 40 are tightened by nuts 41, 42 arranged outside the side walls 32, 32a to set the shape of the core. In the connecting portion 35 of the core 25, the end of one of the members 27 is formed as a small-diameter cylindrical portion 38,
The tapered surface 37 of the insertion portion 36 formed at the end of the other member 26 is inserted into the cylindrical portion 38 to connect the two members 26 and 27 and to allow the connection portion to be sealed. In addition,
The two members constituting the core are configured as symmetric members except that the shape of the connecting portion is different, and one tapered surface 37 of the connecting portion is inserted into the other cylindrical portion. Thereby, a step, a gap or the like is prevented from being generated at the connection portion between the two members. Further, the outer shape of the core is configured so as to correspond to the shape of the connection portion of the cable constituting the connection processing portion using the reinforcing insulator. Is formed in a state in which the connection portion is inserted without a gap. The core 2 of the present invention configured as described above.
5, a plastic material was poured into the interior space 21 of the casting mold to form a reinforcing insulator while being fixed inside the casting mold 20, as shown in FIG. After the cooling action, the plastic material is solidified,
Pull out from the reinforcing insulator. When pulling out the core, one of the nuts 41, 42 that locks both ends of the fixing bolt 40 is removed, the fixing bolt 40 is removed, and the components of the core are removed from both sides of the reinforcing insulator. 26, 2
7 is pulled out using a tool or the like. In addition,
When the core is taken out, for example, Japanese Patent Application Laid-Open No. 5-24056
As disclosed in Japanese Unexamined Patent Publication (Kokai) No. H10-205, a means for pushing out using compressed air may be used. In the present invention, after a plastic material is injected and a reinforcing insulator is molded, a cooling action is applied from a core portion, and the shape of the through hole of the reinforcing insulator changes after cooling. Means that can be used can be used. For this purpose, as shown in FIG. 3 or FIG. 4, a cooling means is arranged inside the core, and after the reinforcing insulator is molded, a cooling effect on the reinforcing insulator is given from the core portion. And a mechanism that enables the shape of the reinforcing insulator to be maintained well and allows the core to be easily extracted. For the purpose described above, in the example shown in FIG. 3 of the present invention, cooling tubes 50 and 50a are arranged in a hollow section defined by a core tube 30, so that cold air or the like is supplied. A means for blowing into the inside of the child and cooling the reinforcing insulator through the tube 30 is constituted. Openings 51 and 51a are provided in portions exposed to the outside of the mold, and cooling pipes 50 and 50a are provided.
a is inserted through the opening, and the refrigerant such as cold air is discharged from the opening.
The cooling operation can be performed from the central portion of the core by disposing the cold air outlet of “a” so as to extend to the deep portion of the tube. In the example shown in FIG. 4, a cooling device is configured by disposing a spiral cooling pipe 55 inside the core tube 30. The cooling pipe 55 extends linearly from the injection port 56 toward the inner side of the pipe, and a spiral pipe is disposed from the center to the end. , The cooling action can be applied sequentially from the connection portion 35 toward the end.
In the cooling means shown in FIGS. 3 and 4, the same cooling means is provided in both of the two members 26 and 27 constituting the core 25 in FIG. 2 so that a cooling action can be given to the core. . As shown in FIGS. 3 and 4, when the cooling means is provided inside the core, the reinforcing insulator is formed by casting a plastic material into the interior space of the casting mold. Then, by supplying the cooling medium to the cooling means disposed on the core, as shown in FIG.
, A cooling action can be performed from the center. Then, when cooling the reinforcing insulator after molding, the plastic material is first cooled at the central portion in contact with the core 25 and solidified, and is uniformly cooled from the inside and cooled sequentially toward the outside. State. Therefore, even if the plastic material shrinks due to cooling, a uniform shrinkage action is performed in the circumferential direction while maintaining the shape of the through hole, and the cylindrical shape of the reinforcing insulator can be accurately set and molded. It will be. In addition, in order to cool the core provided with the cooling means as described above, in addition to using the cooled air as the refrigerant to be supplied to the pipe, a very low temperature Gas can be used. In addition, as shown in FIG. 4, when the pipe is provided in a state where it is not opened to the outside, cold water, a liquid refrigerant, or the like can be used. Further, the cooling action on the core can be set to an arbitrary cooling temperature in accordance with the properties of the plastic material constituting the reinforcing insulator and conditions such as the thickness of the reinforcing insulator, Compared with the conventional natural air cooling, the cooling time after molding can be shortened and the quality of the reinforcing insulator can be improved. The core for manufacturing a reinforced insulator according to the present invention has the above-described structure, and is applicable to a reinforced insulator having a step portion or the like formed in a through hole. Using a core that is split into two parts in the vertical direction, the molding operation can be easily performed, and after molding in a casting mold, also when extracting the core from the reinforcing insulator, Extraction work can be easily performed. Further, when the cooling means is provided for the core, since the cooling action is performed from the central through-hole portion to the outside of the molded reinforcing insulator,
Since the shape of the through-hole can be set first, and the plastic material can be solidified sequentially toward the periphery thereof, the cooling action can be imparted uniformly and the shape of the reinforcing insulator can be set accurately. Furthermore, when the core provided with the cooling means of the present invention is used, it is possible to set the cooling temperature according to the material constituting the reinforcing insulator, and to improve the quality of the reinforcing insulator. Can be.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing a configuration of a casting mold of the present invention. FIG. 2 is an explanatory view showing a configuration of a core of the present invention. FIG. 3 is an explanatory view showing a configuration of a cooling means provided in a core. FIG. 4 is an explanatory view showing the configuration of another embodiment of the cooling means provided in the core. FIG. 5 is an explanatory diagram of a reinforcing insulator cooled by the cooling means of the present invention. FIG. 6 is an explanatory diagram of a connection processing unit configured using a reinforcing insulator. [Description of Signs] 1 cable, 2 conductors, 9.9a conductor connector, 10 connection processing section, 11 reinforcing insulator,
12 through hole, 13 high voltage shield electrode, 16
Protection tube, 20 casting mold, 22 heater, 2
4 extruder, 25 core, 26/27 core member, 30 tube, 31 large diameter part, 33 taper part, 35 connection part, 40 fixing bolt, 5
0.55 cooling pipe.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-58-107313 (JP, A) JP-A-5-46416 (JP, U) JP-A-59-91811 (JP, U) (58) Investigation Field (Int.Cl. ⁷ , DB name) H01R 43/00 B29C 39/22 B29C 39/26 B29C 39/38 H02G 1/14

Claims (1)

(57) [Claim 1] A reinforced insulator used for forming a connection processing part by arranging a spindle-shaped insulator molded in advance on a conductor connection part of a rubber / plastic power cable. When the reinforcing insulator is molded using a mold, a core forming a through hole corresponding to a cable connection portion is constituted by two cylindrical members connectable at a central portion in a length direction. The member constituted by the two substantially cylindrical tubes has a large-diameter portion at both end portions of the core, a small-diameter connection portion disposed at the center portion,
It is constituted by a tapered portion formed between a large diameter portion and a connection portion, and is disposed in a state where a fixing bolt is penetrated in a center portion of the core cylinder, and an end of the fixing bolt is connected to the large diameter portion. The core is set by tightening with a nut disposed outside the side wall of the end of the core, and at the connection part of the core, the end of one member is formed as a small-diameter cylindrical portion, and the other member is formed. After inserting the tapered surface of the insertion portion formed at the end of the other cylindrical portion into the other cylindrical portion to enable sealing of the connection portion, connecting the cooling means inside the core, and molding the reinforcing insulator A core for manufacturing a reinforced insulator, wherein a cooling action on the reinforced insulator is enabled from the core portion.