JP2020138487A - Method for manufacturing insulating spacer - Google Patents

Abstract

To easily and inexpensively provide an insulating spacer which reduces an electric field of a creepage direction component on the surface and is used as a cast article laminated with an insulating resin layer having a desired dielectric ratio.SOLUTION: There are provided a method for manufacturing a cone type insulating spacer including a step of continuously injecting two or more resins having different dielectric constant ratios into a mold 20 for casting which has a center conductor 10 arranged in the central part of a bottom surface and has a bottom surface projecting downward using movable casting nozzles 21a and 21b, the resins being injected while rotating the movable casting nozzles relative to the mold for casting, and a step of heating and molding the resin filling the mold; a cone type insulating spacer manufactured from the same; and a casting device capable of manufacturing them.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for manufacturing an insulating spacer used in a gas-insulated switchgear and an insulating spacer.

The gas-insulated switchgear has a structure in which a high-voltage conductor is arranged in a sealed metal container. In such a gas-insulated switchgear, a solid insulator called an insulating spacer is used to fix the high-voltage conductor at a predetermined position in the sealed container. FIG. 6 is a conceptual cross-sectional view showing an example of a cone-shaped insulating spacer according to the prior art. In this insulating spacer, a high-pressure conductor 100 is provided at the center, and an insulating spacer 120 is provided so as to support the high-pressure conductor 100. A metal flange 110 is attached around the insulating spacer 120, is sandwiched between the connecting flanges of the sealed container 300 by the metal flange 110, and is fixed to the sealed container 300 with bolts 320. The insulating spacer 12 has a shape symmetrical with respect to the axis A, and the cross-sectional structure perpendicular to the axis A is a circular shape in which the high-voltage conductor 100 is arranged in the central portion and the flange 110 is arranged in the peripheral portion. A high-voltage lead (not shown) is attached to the high-voltage conductor 100, and the high-voltage lead electrically penetrates the insulating spacer 120. Insulation spacers used in gas-insulated switchgear come in a variety of other shapes and structures, including disc-shaped ones, those with axisymmetric irregularities, and those through which three high-voltage conductors penetrate. Are known.

In recent years, more economic efficiency has been required, and compact gas-insulated switchgear has been desired. In the conventional insulating spacer, the electric field concentration in the gas space due to the difference in the dielectric constant between the insulating gas containing SF ₆ as the main component and the solid insulator, and the management of conductive foreign substances hinder the compactification. There is. Therefore, in order to reduce the size, it has been studied to reduce the electric field of the creepage component of the surface by changing the dielectric constant of the cone-type insulating spacer in the radial direction (see, for example, Non-Patent Document 1).

Further, the cone-shaped insulating spacer is composed of a plurality of materials in which the mixing ratio of the filler and the epoxy resin is changed with respect to the axial direction of the high-pressure conductor, and the upper portion in the axial direction has a large dielectric constant and forms a convex portion. However, there is known an attempt to improve the insulating performance by making the lower part in the axial direction have a small dielectric constant and forming a recess (for example, Patent Document 1).

Further, it has been proposed that when the insulating spacer is manufactured by casting, resins having different ratios of fillers are continuously injected into the casting mold and heat-molded (see, for example, Patent Document 2). ).

On the other hand, as a resin molding method, there is known a method for producing a rotary molded product in which a polyurethane resin composition having a predetermined composition is used to react and cure the rotary molding while rotating the mold (see, for example, Patent Document 3).

Japanese Unexamined Patent Publication No. 2004-335390 Japanese Unexamined Patent Publication No. 2010-176969 Japanese Unexamined Patent Publication No. 2000-336137

The Institute of Electrical Engineers of Japan Power and Energy Division Conference "Examination of Insulation Performance Improvement Effect of GIS Spacer Using Inclined Dielectric Permittivity Material", Vol. B, No. 405, pp178-179,2000

However, in the insulating spacer disclosed in Patent Document 1, the specific casting method in its production is unknown. When a resin having a different compounding ratio is poured into a mold, the gelled resin in the front layer adheres along the flow path and remains, so that a cast product having a desired dielectric constant cannot be obtained. There is. Further, in the method described in Patent Document 2, there is a problem that the resin layers are mixed in the middle of the injection because the difference in viscosity is small by continuously injecting the resins having different filler ratios.

In view of the above-mentioned problems of the prior art, in the production of an insulating spacer using casting materials having different dielectric constants, when casting resins having different dielectric constants are poured into a mold, upper and lower layers are formed during injection. It is an object of the present invention to provide an insulating spacer as a cast product in which a desired dielectric constant is laminated without being mixed with each other easily and inexpensively.

As a result of diligent studies, the present inventors have made a plurality of resins having different dielectric constants by using a nozzle that is movable in the vertical direction of the casting die and is configured to be relatively rotatable with respect to the casting die. The idea was to pour the plastic into a mold, and the present invention was completed.

According to one embodiment, the present invention is a method for manufacturing a cone-type insulating spacer, in which a central conductor is arranged in the center of the bottom surface and the bottom surface is convex downward. This is a step of continuously injecting two or more kinds of resins having different dielectric constants using a mold nozzle, in which the movable casting nozzle is injected while being relatively rotated relative to the casting mold. It includes a step and a step of heat-molding the resin filled in the mold.

In the injection step of the manufacturing method, it is preferable that the movable casting nozzle is inserted from the upper part of the casting mold, and the movable casting nozzle is movable in the vertical direction and up and down.

It is preferable that the injection step of the manufacturing method includes a step of rotating the movable casting nozzle with respect to the fixed casting mold. And / or the injection step of the manufacturing method preferably includes a step of rotating the casting mold with respect to the fixed movable casting nozzle.

It is preferable that the injection step of the manufacturing method includes a step of discharging the resin from the movable casting nozzle while moving the movable casting nozzle upward in the vertical direction.

According to another embodiment, the present invention is a cone-shaped insulating spacer provided around the central conductor in support of the central conductor, and one surface of the central conductor along the axial direction is a convex surface. , The other surface is a concave surface, and a plurality of insulating resin layers having different dielectric constants are included from the convex surface to the concave surface, and the plurality of insulating resin layers are arranged in a spiral shape. Regarding spacers.

According to another embodiment, the present invention relates to a cone-type insulating spacer manufactured by the manufacturing method according to any one of the above.

According to yet another embodiment of the present invention, the cone-type insulating spacer according to any one of the above, which is a gas-insulated switchgear and is sandwiched and fixed by a connecting flange of a cylindrical sealed container. Be prepared.

According to yet another embodiment, the present invention is for a cone-type insulating spacer, which is a casting device having a cavity whose bottom surface is convex downward and a nozzle introduction port communicating with the cavity at the top. It includes a casting mold and a movable casting nozzle that is movable in a vertical direction and up and down with respect to the casting mold and is configured to be rotatable with respect to the casting mold.

The casting device further includes a casting tank for accommodating the casting mold and the movable casting nozzle, and the casting tank provides a rotating mechanism for rotating the casting mold in the horizontal direction. It is preferable to prepare. And / or, in the casting device, a casting tank for accommodating the casting mold and the movable casting nozzle is further provided, and the casting tank horizontally holds the movable casting nozzle. It is preferable to provide a rotating mechanism for rotating.

According to the method for manufacturing an insulating spacer according to the present invention, in the manufacturing of an insulating spacer using different dielectric constant materials, when the resin having a different compounding ratio is poured into the mold, the resin layers are not mixed during the injection. Insulating spacers as cast products in which different dielectric constants are laminated can be obtained easily and inexpensively. In particular, since resins having different dielectric constants can be continuously laminated, waste of the resin can be reduced while avoiding mixing of the resins.

FIG. 1 is a conceptual cross-sectional view illustrating a method for manufacturing a cone-type insulating spacer according to an embodiment of the present invention and a casting device used therefor. FIG. 2 is a plan view taken along the line AA of FIG. FIG. 3 is a conceptual cross-sectional view illustrating a method for manufacturing a cone-type insulating spacer according to another embodiment of the present invention, and a casting device used for the method. FIG. 4 is a diagram conceptually explaining a resin injection step in the method for manufacturing a cone-type insulating spacer according to an embodiment of the present invention. FIG. 5 is a conceptual cross-sectional view showing a cone-shaped insulating spacer according to an embodiment of the present invention and a part of a sealed container provided with the cone-shaped insulating spacer. FIG. 6 is a conceptual cross-sectional view illustrating a cone-shaped insulating spacer according to the prior art.

Hereinafter, embodiments of the present invention will be described. However, the present invention is not limited to the embodiments described below.

[First Embodiment: Manufacturing method of cone type insulating spacer]
According to the first embodiment, the present invention relates to a method for manufacturing a cone-type insulating spacer. The production method according to the present invention includes at least the following steps.
1) Using a movable casting nozzle, two or more types of resins with different dielectric constants are continuously placed in a casting mold with a convex bottom surface and a central conductor arranged in the center of the bottom surface. A step of injecting the resin while rotating the movable casting nozzle relative to the casting mold. 2) A second step of heat-molding the resin filled in the mold.

With reference to FIGS. 1 and 2, a casting device according to a first aspect that can be used in the method for manufacturing a cone-type insulating spacer according to the first embodiment will be described. Referring to FIG. 1, the casting device includes a casting mold 20 housed in a casting tank 40, movable casting nozzles 21a and b, and a rotation mechanism 42.

The casting mold 20 is convex downward in the vertical direction, and has a cavity 13 in which the central conductor 10 can be installed in the central portion of the convex bottom surface. The shape of the cavity 13 can be appropriately designed to match the shape of the desired cone-shaped insulating spacer. More specifically, the cavity 13 can be designed into a shape capable of producing a cone-shaped insulating spacer having the cross-sectional shape shown in FIG. 5 described in detail later. The casting die 20 is generally a casting die. Hereinafter, in the present specification, the casting mold and the casting mold are used interchangeably and have the same reference numerals, but the casting mold constituting the present invention is not limited to the metal mold. .. The casting die 20 is provided with an introduction port 23 into which the movable casting nozzles 21a and b can be inserted on the upper surface or the side surface of the casting die 20. FIG. 2 is a plan view taken along the line AA of FIG. 1, which is a plan view of the casting mold 20 and the movable casting nozzles 21a and b from above the casting mold 20. Referring to FIG. 2, a groove-shaped introduction port 23 along the circumference is provided in the vicinity of the outer edge portion of the upper surface of the substantially circular mold. Although not shown, the introduction port 23 may be provided above the side surface of the mold. The introduction port 23 communicates with the cavity 13, and the movable casting nozzles 21a and b can be moved vertically upward and downward through the introduction port 23, and is movable by the circular groove-shaped introduction port 23. The casting nozzles 21a and b can be continuously rotated.

The movable casting nozzles 21a and 21b are devices capable of injecting resin as a material for an insulating spacer into the casting mold 20, and may be a heat-resistant and flexible conduit or the like. Examples of the movable casting nozzles 21a and b include, but are not limited to, a silicone rubber tube and a fluororubber tube. The movable casting nozzles 21a and 21b are connected to a drive unit 41 and a resin preparation / storage unit (not shown). The drive unit 41 may include a drive mechanism capable of moving the movable casting nozzles 21a and b vertically upward and downward, and includes, but is not limited to, a power cylinder, a servomotor, and the like. .. By the drive unit 41, the tips of the movable casting nozzles 21a and b can be moved upward and downward in the vertical direction in the cavity 13, and the nozzle tips are arranged at desired positions in the cavity 13 to place the resin. It can be discharged. Here, the phrase "movable upward and downward in the vertical direction" includes movement in the diagonally upward direction and diagonally downward direction, if accompanied by movement in the vertical direction upward and downward. In this respect, an action different from the conventional method in which the resin is introduced by a pipe fixed from a fixed injection port of the mold or the like becomes possible.

In the illustrated embodiment, two movable casting nozzles 21a and b are provided, and the two nozzles are located on the diameter of the circle when the casting die 20 is viewed in a plan view from above in the vertical direction. It is fixed to the drive unit 41 in such an manner. However, the present invention is not limited to the number and arrangement of specific nozzles. For example, the number of nozzles may be one, or three or more nozzles, for example, four nozzles may be provided evenly along the circumference of the circular groove serving as the introduction port 23.

The resin preparation / storage unit (not shown) stores two or more types of resin to be injected into the casting mold 20, or prepares a predetermined composition as needed, and a control unit (not shown) provides a movable casting nozzle. Resin is continuously supplied to 21a and 21b. Such a resin preparation / storage unit may include a storage tank containing a filler and a thermosetting resin in different proportions, a mixing device for mixing these, and a control device for controlling the composition. Not limited to these.

The rotation mechanism 42 is a device that rotates the casting die 20 in the horizontal direction about the axis P. The rotation mechanism 42 is controlled in conjunction with the drive unit 41 by a control unit (not shown) to rotate the rotation mechanism 42 at a desired speed and direction. As a result, the casting die 20 can be rotated relative to the movable casting nozzles 21a and b fixed to the casting tank 40. Further, the casting device according to this embodiment may include a casting mold 20, a movable casting nozzles 21a and b, a driving unit 41 thereof, and a casting tank 40 accommodating a rotation mechanism 42. The casting tank 40 may include a heater capable of heating the inside of the tank, or may be configured to be connectable to a vacuum pump so that the pressure can be reduced.

Next, the casting device according to the second aspect will be described with reference to FIG. Referring to FIG. 3, the casting device includes a casting mold 20 housed in the casting tank 40 and movable casting nozzles 21a and b supported by a drive unit 41 further including a rotation mechanism 43. Is equipped with. In this aspect, the configuration of the casting die 20 and the movable casting nozzles 21a and b may be the same as the casting device according to the first aspect described with reference to FIGS. 1 and 2. In the casting device according to the second aspect, the casting mold 20 is fixed in the casting tank 40, and the drive unit 41 that supports the movable casting nozzles 21a and b is provided with the rotation mechanism 43. As a result, the movable casting nozzles 21a and b can rotate around the axis P, and the movable casting nozzles 21a and b can be rotated relative to the casting mold 20.

Although not shown, both the casting mold and the movable casting nozzle can be configured to be rotatable, and the same operation as that of the device according to the first and second aspects can be obtained.

Next, the manufacturing method according to this embodiment will be described with reference to FIG. FIG. 4 is a conceptual diagram schematically explaining the rotational movement of the nozzle and the laminating mode of the resin in the injection step. In FIG. 4, a casting device having one movable casting nozzle is used. It will be explained by an example. Further, the relative positional relationship between the movable casting nozzle and the casting mold 2 will be illustrated and described without specifically showing the rotation mechanism. In the first step of the manufacturing method according to the present embodiment, two or more kinds of resins having different dielectric constants are continuously injected by using the movable casting nozzle 21.

The resin used in this step may be a fluid insulating resin having a dielectric constant of 3 to 40 that can be heat-cured and function as an insulating spacer. In particular, it is preferable that the resin has a relatively high viscosity at the time of casting, which is about 1000 to 20000 mPa · sec. Specifically, it may be a thermosetting resin containing a filler, and the thermosetting resin may be, for example, an epoxy resin, a maleimide resin, a cyanate resin, or a mixture thereof.

The thermosetting resin is preferably an epoxy resin. The epoxy resin preferably contains an epoxy resin main agent, a curing agent, and optionally a curing accelerator. As the epoxy resin main agent, an aliphatic epoxy, an alicyclic epoxy, or a mixture thereof can be used. Examples of the aliphatic epoxy resin include, but are not limited to, bisphenol A type epoxy, bisphenol F type epoxy, bisphenol AD type epoxy, biphenyl type epoxy, cresol novolac type epoxy, and trifunctional or higher functional polyfunctional type epoxy. .. These can be used alone or in combination of two or more. Examples of the alicyclic epoxy resin include, but are not limited to, monofunctional epoxy, bifunctional epoxy, and trifunctional or higher polyfunctional epoxy. The alicyclic epoxy resin can also be used alone or in combination of two or more different alicyclic epoxy resins.

The curing agent for the thermosetting resin is not particularly limited as long as it can react with the epoxy resin main agent and cure, but it is preferable to use an acid anhydride-based curing agent. Examples of the acid anhydride-based curing agent include aromatic acid anhydrides, specifically, phthalic anhydride, pyromellitic anhydride, trimellitic anhydride and the like. Alternatively, cyclic aliphatic acid anhydrides, specifically tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, etc., or aliphatic acid anhydrides, specifically. Specific examples thereof include succinic anhydride, polyadipic anhydride, polysevacinic anhydride, polyazelineic anhydride and the like, but are not particularly limited. Further, as the curing accelerator, imidazole or a derivative thereof, a tertiary amine, a borate ester, a Lewis acid, an organometallic compound, an organoacid metal salt and the like can be appropriately used, but is not particularly limited.

The filler is contained in the resin in a composition and an amount so that the dielectric constant of the resin used is a desired dielectric constant. As the filler, an insulating inorganic filler can be used. As the filler for preparing a resin having a relatively low dielectric constant, alumina, silica, dolomite or the like having a relative permittivity of less than 10 can be used, and the filler for preparing a resin having a relatively high dielectric constant can be used. As the filler, barium titanate, strontium titanate and the like can be used, but the filler is not limited thereto.

In the present embodiment, the composition of the resin to be injected is such that the thermosetting resin main agent, the curing agent, the curing accelerator and the inorganic filler are optionally used, and the desired physical properties such as dielectric constant and heat resistance are achieved. As such, those skilled in the art can make the appropriate decisions. The target dielectric constant value is preferably designed so that the ratio of the dielectric constant of the resin having the lowest dielectric constant to the resin having the highest dielectric constant is 3 to 4. Further, it is preferable to design so that the difference in dielectric constant between the continuously injected resins is, for example, less than 1. If the difference in dielectric constant between the continuously injected resins is too large, there may be a problem that the electric field is concentrated on the surface of the spacer having an interface. Further, the viscosities between the plurality of different resins may be different or similar.

In this step, two or more kinds of resins having different dielectric constants are used, and the kind of the resin is preferably three or more kinds. Therefore, it may be four to ten or more. That is, the permittivity of the injected resin differs in at least two stages, and may vary from three stages to ten stages or more. These two or more different types of resins can be prepared to a desired composition by a resin preparation unit (not shown) connected to the movable casting nozzle 21. Then, a resin having a predetermined composition is sent to the movable casting nozzle 21 in a predetermined amount by a control unit (not shown) so that the resin can be injected into the casting mold 20. According to one aspect, the order of injecting two or more kinds of resins having different dielectric constants may be the order of increasing dielectric constants. Alternatively, the order of injection may be in ascending order of dielectric constant or in order of varying dielectric constant from large, small, and medium, and is not particularly limited. Hereinafter, the present invention will be described by exemplifying the case of injecting in descending order of dielectric constant, but the present invention is not limited to a specific embodiment regarding the order of injecting two or more kinds of resins having different dielectric constants.

In the present embodiment, "continuously" injection means that resins having different compositions are continuously supplied to the movable casting nozzle 21, and the discharge from the movable casting nozzle 21 is substantially performed through the injection step. It shall be done without interruption.

Hereinafter, the case where five types of resins to be injected will be described as an example. In this example, each resin is designated as a first resin, a second resin, a third resin, a fourth resin, and a fifth resin in descending order of dielectric constant, and the first resin, the second resin, and the third resin are designated. The resin, the fourth resin, and the fifth resin are injected into the casting mold 20 in this order. However, in the present invention, the types of resins having different dielectric constants are not limited to five types, and the injection order is not limited to a specific order.

First, the movable casting nozzle 21 is inserted into the casting mold 20 to inject the first resin having the highest dielectric constant. At the start of injection of the first resin, the tip of the movable casting nozzle 21 is positioned near the bottom surface of the casting mold 20. Then, the first resin 12a is discharged from the movable casting nozzle 21 while moving the movable casting nozzle 21 upward and rotating the movable casting nozzle 21 relative to the casting mold 20. While injecting the first resin 12a, it is preferable to raise the tip of the movable casting nozzle 21 as the liquid level of the first resin 12a rises. For example, the tip of the movable casting nozzle 21 can be raised so as to be located near the liquid surface within a range where the tip of the movable casting nozzle 21 does not touch the liquid surface of the first resin 12a. FIG. 4A conceptually shows the state of the resin and the nozzle at the time when the movable casting nozzle 21 is rotated by 180 ° relative to the casting mold 20 after the injection of the first resin 12a is started. Those skilled in the art can appropriately determine the injection speed of the first resin 12a, the ascending speed of the tip of the movable casting nozzle 21, and the rotation speed.

Next, when the movable casting nozzle 21 rotates 360 ° relative to the casting mold 20, the resin to be discharged is switched to the second resin. If there are two movable casting nozzles 21, The resin can be switched when it is rotated by 180 °, or the resin to be discharged can be switched at a desired time according to the design of those skilled in the art. The switching to the second resin is preferably performed so that the first resin and the second resin are continuously discharged in the movable casting nozzle 21 without interruption. FIG. 4B conceptually shows the resin stacking state and the nozzle position when the movable casting nozzle 21 rotates 180 ° relative to the casting mold 20 after the injection of the second resin 12b is started. Shown.

Similarly, after switching to the second resin, when the movable casting nozzle 21 rotates 360 ° relative to the casting mold 20, the resin to be discharged is switched to the third resin having a lower dielectric constant. .. FIG. 4C conceptually shows the resin stacking state and the nozzle position when the movable casting nozzle 21 rotates 180 ° relative to the casting mold 20 after the injection of the third resin 12c is started. Shown. Further, after switching to the third resin 12c, when the movable casting nozzle 21 rotates 360 ° relative to the casting mold 20, the resin to be discharged is switched to the fourth resin having a lower dielectric constant. FIG. 4D conceptually shows the resin stacking state and the nozzle position when the movable casting nozzle 21 rotates 180 ° relative to the casting mold 20 after the injection of the fourth resin 12d is started. Shown. Although not shown, the cavity 13 can be filled with the resin by similarly switching to the fifth resin and injecting the resin to complete the resin injection step. The present invention is not limited to the embodiment in which one type of resin is injected while the nozzle 21 rotates 180 ° relative to the casting die 20, and the injection is performed at shorter intervals. The type of resin can be changed, or one type of resin can be injected over, for example, 360 ° rotation. It is also possible to inject while continuously changing the concentration of the resin. Further, even when the order of resin injection is not the order of increasing dielectric constant, the injection step can be carried out in the same manner as described above.

In the heat molding step, which is the second step, the resin filled in the mold is heat molded. In the first step, after the resin layers are spirally laminated, heat molding is performed. Conditions such as heating temperature and time can be appropriately determined by those skilled in the art so as to match the curing conditions of the thermosetting resin to be used. For example, when the thermosetting resin main agent is an epoxy resin, it can be set at about 120 to 140 ° C. for about 1 to 5 hours, but is not limited to specific conditions. In some cases, curing by two-step heating can also be performed. Further, the heating can be carried out under atmospheric pressure or under reduced pressure.

FIG. 5 shows a schematic cross-sectional view when the insulating spacer obtained through the first and second steps is installed in a closed container. In FIG. 5, a cone-shaped insulating spacer 12 is formed around the central conductor 10, and one surface of the central conductor 10 along the axis A direction is a convex surface and the other surface is a concave surface. A metal flange 11 is provided on the outer periphery of the insulating spacer 12, and the metal flange 11 is fixed to the closed container 30 by bolts 32. In the cone-type insulating spacer 12, a plurality of insulating resin layers 12a, 12b, 12d, and 12e having different dielectric constants, for example, gradually decreasing, are spirally laminated from a convex surface to a concave surface along the axis A. There is. When viewed in a plan view from the convex side, the insulating resin layers 12a, 12b, 12d, and 12e are arranged in this order from the inside to the outside in the radial direction with the axis A as the center. Then, in the insulating spacer according to the present invention, these insulating resin layers 12a to e are hardly mixed with each other. Note that FIG. 5 is a cross-sectional view conceptually showing the laminated state of the resin, but the thickness (amount of laminated resin) of each layer having a different dielectric constant is not limited to the illustrated embodiment. For example, in the vicinity of the central portion of the convex surface, that is, the peripheral edge portion of the central conductor 10, the thickness (amount of laminated resin) of each layer having a different dielectric constant is reduced, and the resins having different dielectric constants are gradually laminated in multiple layers. be able to. This is to prevent electric field concentration at the relevant location. On the other hand, in the outer peripheral portion close to the flange 11, resin layers having the same dielectric constant may be laminated relatively thickly. Further, as described in the injection step, the spiral lamination mode of the resin layers having different dielectric constants is limited to the case where a plurality of insulating resin layers whose dielectric constants gradually decrease form adjacent layers. However, the dielectric constant may be gradually increased or repeatedly increased or decreased, and even in the layer formed during the rotation of the nozzle at 180 ° or 360 °, the dielectric constant may be increased. May be changed so as to continuously decrease, increase, or increase or decrease.

[Second Embodiment: Casting Device]
The present invention relates to a casting device according to a second embodiment. The casting device is the device described in the manufacturing method according to the first embodiment, and is a casting mold for a cone type insulating spacer, a movable casting nozzle, a casting mold and / or a movable casting nozzle. Includes at least a rotating mechanism that can rotate horizontally. Optionally, a casting tank for accommodating these may be provided.

The specific configuration and mode of the casting device according to the present embodiment are as described in detail with reference to FIGS. 1 to 3 in the first embodiment, and the usage thereof is also described in detail with reference to FIG. As you did. According to the casting apparatus according to the present embodiment, it is possible to obtain an insulating spacer in which two or more kinds of resins having different dielectric constants are laminated in a spiral shape, which could not be manufactured by the prior art.

The insulating spacer according to the present invention can be used in a gas-insulated switchgear.

10 center conductor, 11 flange,
12a 1st resin, 12b 2nd resin, 12c 3rd resin, 12b 4th resin,
12e 5th resin, 13 cavity 20 casting mold,
21, 21a, 21b Movable casting nozzle, 23 inlet 30 sealed container, 32 metal flange 40 casting tank, 41 drive unit, 42, 43 rotation mechanism

Claims (11)

Using a movable casting nozzle, two or more types of resins with different dielectric constants are continuously injected into a casting mold with a central conductor arranged in the center of the bottom surface and a convex bottom surface. A step of injecting the movable casting nozzle while rotating the movable casting nozzle relative to the casting mold.
A method for manufacturing a cone-type insulating spacer, which comprises a step of heat-molding the resin filled in the mold. The manufacturing method according to claim 1, wherein in the injection step, the movable casting nozzle is inserted from the upper part of the casting mold, and the movable casting nozzle is movable in the vertical direction up and down. The manufacturing method according to claim 1 or 2, wherein the injection step includes a step of rotating the movable casting nozzle with respect to the fixed casting mold. The manufacturing method according to claim 1 or 2, wherein the injection step includes a step of rotating the casting mold with respect to the fixed movable casting nozzle. The production according to any one of claims 1 to 3, wherein the injection step includes a step of discharging resin from the movable casting nozzle while moving the movable casting nozzle upward in the vertical direction. Method. A cone-type insulating spacer that supports the center conductor and is provided around the center conductor.
One surface of the central conductor along the axial direction is a convex surface, the other surface is a concave surface, and a plurality of insulating resin layers having different dielectric constants are included from the convex surface to the concave surface. A cone-type insulating spacer in which the insulating resin layers of the above are arranged in a spiral shape. A cone-type insulating spacer manufactured by the manufacturing method according to any one of claims 1 to 5. The gas-insulated switchgear comprising the cone-shaped insulating spacer according to claim 6 or 7, which is sandwiched and fixed by a connecting flange of a cylindrical sealed container. A casting mold for a cone-type insulating spacer, which has a cavity whose bottom surface is convex downward and a nozzle introduction port which communicates with the cavity at the top.
A casting device including a movable casting nozzle that is movable in a vertical direction and up and down with respect to the casting mold and is configured to be rotatable with respect to the casting mold. Further provided with a casting tank for accommodating the casting mold and the movable casting nozzle.
The device according to claim 9, wherein the casting tank includes a rotation mechanism for rotating the casting mold in a horizontal direction. Further provided with a casting tank for accommodating the casting mold and the movable casting nozzle.
The device according to claim 9 or 10, wherein the casting tank includes a rotation mechanism for rotating the movable casting nozzle in a horizontal direction.