JP3472075B2 - Manufacturing method of insulation resin casting - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a casting product obtained by molding a conductor requiring ground insulation with an insulating resin, such as a magnetic levitation railway propulsion coil or a secondary coil of a through current transformer. The present invention relates to a method of manufacturing an insulating resin cast product to be manufactured.

[0002]

2. Description of the Related Art As a cast product obtained by molding the outer periphery of a conductor with an insulating resin, for example, a propulsion coil used in a magnetic levitation railway, a secondary coil of a feedthrough rectifier, and the like can be mentioned. In such a coil, since a high voltage is applied between the wound body of the conductive material that constitutes the coil body and the ground, it is necessary to secure an insulation distance between them that can withstand the high voltage. . Therefore, these coils have a structure in which the outer circumference of the coil body made of the wound body of the conductive material is molded with an insulative casting resin to a thickness corresponding to the insulation distance.

For example, the molding of the insulating resin in the propulsion coil is performed by cast molding. That is,
The coil body is held in a casting mold formed to be larger than the coil body, and an insulating resin is injected between the inner peripheral surface of the casting mold and the outer peripheral surface of the coil to cure. It is done by letting.

Incidentally, in this casting, in order to secure the insulation distance, it is necessary to hold the coil body in a state where the coil body and the inner surface of the casting die are separated by a certain distance. is there.

Therefore, as a means for this, insulating particle spacers are dispersed and adhered to the inner wall surface of the casting mold in advance, and the insulating distance is surely secured by the insulating spacers. A method is adopted to enable setting.

According to such a manufacturing method, the injected insulating resin is filled in the gap between the coil body secured by the insulating spacer and the inner surface of the mold, and is cured to form a desired coil. Obtainable.

[0007]

By the way, in the casting step, the inside of the casting die is maintained in a substantially vacuum state. Therefore, the insulating resin injected into the mold is strongly defoamed. The bubbles generated by defoaming can flow in the resin as long as the insulating resin has a low viscosity, but at the stage where the curing reaction progresses and the liquid state changes to a gel state, the insulating spacer and the uneven portion on the outer surface of the coil body are formed. It may adhere to the minute space defined by, and may reach the flow limit and remain as it is.

In addition, when the curing reaction of the insulating resin progresses and the resin shrinks from the gel state to the solid state, a shrinkage occurs at the interface between the insulating spacer, the coil body and the insulating resin starting from the residual air bubbles, and a minute mark occurs. There is a gap. If such a minute gap exists at the interface of the insulating spacer, the resin may be carbonized by partial discharge under a high electric field, and trees may be generated along the interface of the insulating spacer to cause dielectric breakdown in a relatively short time. .

The present invention has been made in view of the above circumstances, and provides a method for producing a resin-resin cast product capable of maintaining an initial insulating property for a long period of time even after cast molding. That is the purpose.

[0010]

A first means of the present invention is to provide a gap between an inner surface of a casting mold and a conductor when holding a conductor requiring ground insulation in the casting mold. In the method of manufacturing an insulating resin cast product in which the conductor is cast with the insulating resin by interposing an insulating spacer in the gap and injecting the insulating resin into the gap to solidify the conductor, the conductor is positioned in the casting mold. Prior to this, the method for producing an insulating resin cast product is characterized by including a step of adhering an insulating sheet material covering the concavo-convex portion to the concavo-convex portion of the conductor facing the insulating spacer.

With such a structure, it is possible to prevent a minute space from being formed at the boundary between the insulating spacer and the conductor, so that it is possible to effectively prevent bubbles from remaining in this portion during casting.

At least a part of the insulating sheet is preferably made of a material having an affinity with the insulating resin, and more preferably a glass tape or a polyester non-woven fabric.

Further, an insulating sheet material may be adhered to the conductor, followed by impregnation with a resin and heating and curing. Alternatively, after filling uneven portions of the conductor with glass fiber,
The insulating sheet material may be attached and cured by heating.

As the insulating spacer, it is preferable to use an insulating spacer obtained by sandblasting the surface and then subjecting it to a primer treatment with a resin of the same system as the casting resin.

With such a structure, it is possible to prevent the adhesion of water or fouling substances to the surface of the insulating spacer. Therefore, it is possible to prevent bubbles from being generated and remaining in the insulating resin due to the evaporation.

The same effect can be obtained by using, as the insulating spacer, an insulating spacer obtained by subjecting the surface to sandblasting and then vacuum heating to remove trace components attached to the surface of the insulating spacer. .

Further, even if an insulating spacer made of a material having low water absorption is used as the insulating spacer, the same effect as above can be obtained, and it is preferable to adopt ceramic as such a material.

In the second means, when a conductor requiring ground insulation is held in the casting mold, an insulating spacer is interposed in the gap between the inner surface of the casting mold and the conductor. In a method of manufacturing an insulating resin cast product in which the conductor is cast with an insulating resin by injecting and solidifying an insulating resin into the insulating resin, as the insulating spacer, at least a part of a surface of the conductor surface facing the uneven portion is formed. The method for producing an insulating resin cast product is characterized in that an insulating spacer having a protrusion whose abutting portion is in contact with the uneven portion is used.

According to this structure, the contact area between the unevenness and the insulating spacer can be reduced, so that a minute space can be prevented from being formed at the interface between these.
This makes it possible to obtain the same effect as the first means.

The protrusions are preferably formed with a size corresponding to the recesses or protrusions of the concavo-convex portion of the conductor. A third means is to hold a conductor requiring ground insulation in a casting mold by interposing an insulating spacer in a gap between the inner surface of the casting mold and the conductor, and insulating resin in the gap. In the method of manufacturing an insulating resin cast product in which the conductor is cast with an insulating resin by injecting and solidifying the insulating resin, an insulating spacer having a thickness smaller than the distance of the ground insulation is used as the insulating spacer. A method for manufacturing an insulating resin cast product, comprising a step of restricting contact between the insulating spacer and a conductor by fixing the spacer to the mold.

According to this structure, the contact between the insulating spacer and the conductor can be restricted, so that the minute space can be prevented from being formed between them. This makes it possible to obtain the same effect as the first means.

For fixing the insulating spacer, an insert portion to be inserted into a concave portion provided in the mold is provided in a part of the insulating spacer, and a Teflon ring is mounted on the insert portion and then provided on the mold. It is preferable to firmly fix the Teflon ring by inserting it into the recess and expanding the Teflon ring by heating. With such a configuration, it is possible to prevent the insulating spacer from collapsing.

In addition, the insulating spacer is fixed to a mold, the insulating spacer is covered with a heat-shrink cap, and the heat-shrink cap shrinks by heating, so that the space between the conductor and the insulating spacer is reduced. A gap may be created.

Further, a sheet layer that thermally expands is inserted between the insulating spacer and the conductor, and the sheet layer expands due to the heat of the mold and the heat generated by the casting resin at the time of curing to form a gap that is forcibly formed. The casting resin may be injected into the.
With such a structure, it is possible to form a stronger insulating resin layer.

A fourth means is to interpose an insulating spacer in the gap between the inner surface of the first casting mold and the conductor requiring ground insulation, and inject the insulating resin into this gap to solidify it. A first insulating resin casting step of casting a conductor with an insulating resin, a casting product manufactured in the first insulating resin casting step, and a second
And a second insulating resin casting step of casting the casting product with the insulating resin by interposing an insulating spacer in the gap between the casting mold and injecting and solidifying the insulating resin into the gap. And a method for manufacturing an insulating cast product.

According to this structure, even if a small amount of air bubbles remain between the bottom of the insulating spacer and the conductor, a plurality of insulating spacers are discontinuously arranged between the conductor and the ground. By using it, the creepage distance increases, so that the insulation characteristics do not deteriorate and a cast product with excellent insulation properties can be obtained. In addition,
Even better insulating characteristics can be obtained by shifting the positions of the first and second insulating spacers from each other and performing casting.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. First, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a front view showing a propulsion coil 1 formed by the manufacturing method of the present invention. This propulsion coil 1 is basically composed of a coil main body 2 formed by winding a conductive strip in a substantially oval shape, and an insulating resin mold body 3 that insulates the coil main body 2 from ground. As described in the section of the conventional example, this propulsion coil 1 holds the coil body 2 in a casting mold 4 having an outline shown by a dashed line in the drawing, and the coil body 2 and the casting mold 4 are Four
It is manufactured by injecting an insulating resin (casting resin) into the gap between and to form the insulating resin molded body 3.

The insulating resin mold body 3 must be formed with a thickness corresponding to a predetermined ground insulation distance. Therefore, by interposing an insulating spacer 5 shown in this figure between the inner surface of the casting mold 4 and the coil body 2, it is possible to inject a resin having a size corresponding to a required insulating distance. I try to secure a gap.

After the insulating resin is injected into the gap and cured, the insulating spacer 5 is embedded in the cured insulating resin, and forms the insulating resin mold body 3 integrally with the insulating resin.

The method of manufacturing the propulsion coil 1 will be described in detail below with reference to FIG. This FIG. 2 shows I- of FIG.
It corresponds to the I section, and shows the state in which the coil body 2 is held in the cavity 6 of the casting mold 4 via the pair of upper and lower insulating spacers 5. As shown in this figure, the coil body 2 includes a winding body 7 (conductor) of a conductive strip 7a and an insulating tape 8 (insulating sheet material) wound around the winding body 7.

The wound body 7 is formed by winding a long conductive strip 7a around a winding die a plurality of times while performing interlayer insulation. In this embodiment, as shown in the figure, the wound body 7 is made of a conductive strip 7a wound in five layers, and the upper and lower end surfaces thereof have irregularities 9.

The insulating tape 8 is provided in order to eliminate or reduce a minute space formed at the boundary portion when the insulating spacer 5 is directly brought into contact with the unevenness 9, and at least the insulating spacer 5 is provided. It must be provided in the contact area. As this insulating tape 8,
A material having affinity with the insulating resin is preferable, and for example, glass tape or polyester non-woven fabric is preferable.

On the other hand, the insulating spacer 5 is a resin molded product formed of the same or similar material as the insulating molded body 3, and has a thickness dimension corresponding to the insulating distance required at the place of use, for example, After cutting into a shape like an abacus ball,
Chamfering is performed to form the shape shown in this figure. Then, sandblasting is performed to improve the adhesiveness of the surface, and the surface is treated with a resin of the same system as the casting resin to prevent water and stain components from adhering.

The insulating spacers 5 are previously bonded to the inner surfaces of the upper mold 4a and the lower mold 4b constituting the casting mold 4 with an instant adhesive material or the like. Then, first, the coil body 2 is positioned in the cavity of the lower die 4b, and then the upper die 4b is closed.
Will be retained in the cavity in the state shown in FIG. At this time, the insulating tape 8 is interposed at the interface between the insulating spacer 5 and the irregularities 9 of the wound body 7.

Next, the casting mold 4 is preheated to reduce the pressure in the cavity 6, and then the casting mold 4 is filled with a casting resin to be cooled and solidified. This makes the propulsion coil 1
Can be obtained.

With this structure, the following effects can be obtained. First, since the unevenness 9 generated on the surface of the wound body 7 is covered with the insulating tape 8 and direct contact between the unevenness 9 and the insulating spacer 5 is restricted, the bottom of the insulating spacer 5 and the unevenness 9 are formed. It is possible to prevent the generation of a minute space that occurs at this boundary portion when directly contacting the.

This effectively prevents the bubbles generated by the encapsulation of the insulating resin from remaining on the bottom of the insulating spacer 5, so that the bubbles may be generated by curing the resin while remaining. It is possible to effectively prevent the presence of minute gaps. As a result, dielectric breakdown due to this minute gap can be effectively prevented, and this propulsion coil 1 can be used satisfactorily for a long period of time.

Secondly, since the surface of the insulating spacer 5 is sandblasted and then subjected to the primer processing, it is possible to prevent water and stain components from adhering to the surface of the insulating spacer 5. It is possible to effectively prevent bubbles that may be generated.

That is, since the surface of the insulating spacer that has been only sandblasted is roughened by an abrasive material and has fine irregularities, water and stain components may easily adhere depending on the management method. In the casting process of the propulsion coil, since the inside of the mold is kept in a high vacuum state, these water and pollutant components evaporate from the insulating spacers with moisture and pollutant components adhering to the surface to form bubbles. There is a risk that they will remain on the surface of the insulating spacer.

However, the insulating spacer 5 of this embodiment is
Is sand-blasted on the surface, and is then primed with a resin of the same type as the insulating resin, and the insulating spacers 5 that have been primed have minute irregularities covered with the resin. Little adhesion of Therefore, the use of the insulating spacer 5 of this embodiment can prevent the generation of bubbles. Therefore, the same effect as the first effect can be achieved.

FIG. 3 shows a modified example of the first embodiment. After winding the insulating tape 8 around the winding body 7, the insulating tape 8 may be impregnated with resin under a reduced pressure condition and cured by heating. By performing this treatment, the resin infiltrates into the gap between the insulating tape 8 and the wound body 7 as shown in FIG. 11 to form a strong insulating layer, so that the insulating performance can be improved.

Further, FIG. 4 shows a further modified example of the first embodiment. In this modified example, after the glass fiber 12 is filled in the concave and convex portions 9 of the wound body 7, the insulating tape 8 is wound, impregnated with the insulating resin under reduced pressure, and cured by heating. By packing the glass fiber 12 in the uneven portion 9, it is possible to prevent the uneven portion 9 from being deformed due to curing shrinkage of the resin.

In the first embodiment, the insulating spacer 5 is coated with a primer to cover irregularities on the surface of the insulating spacer 5, but the insulating spacer is not treated with a primer. However, if it is used after being subjected to a vacuum heat treatment, it is possible to remove the trace components adhering to the minute irregularities on the surface of the insulating spacer, and thus it is possible to prevent the generation of bubbles or the like.

Further, the effect of this embodiment can be enhanced even if a material having relatively small water absorption, such as ceramics, is used as the material of the insulating spacer 5 instead of the resin. When ceramics or the like having low water absorbency can be easily removed by heating to remove foreign substances and water adhering to the surface, it may be difficult for air bubbles to adhere to the resin.

Next, a second embodiment of the present invention will be described with reference to FIG. The manufacturing steps not described in the second embodiment are the same as those in the first embodiment.

In this embodiment, the insulating spacer shown in FIG. 14 is used. The insulating spacer 14 has a spherical protrusion 15 having a width dimension equal to or smaller than the width of the conductive strip 7a forming the winding body 7 on at least a part of the bottom portion (the surface facing the winding body 7). Is provided. According to such a configuration, the wound body 7 and the insulating spacer 1
Since it is possible to reduce the contact area with the bottom portion of No. 4, it is possible to prevent the formation of a minute space at these boundary portions.

Therefore, it is possible to prevent bubbles from remaining in this portion without providing the insulating tape 8 as in the first embodiment. This makes it possible to obtain substantially the same effect as that of the first embodiment.

Next, a third embodiment will be described with reference to FIG. The manufacturing steps not described in the second embodiment are the same as those in the first embodiment. In the manufacturing method of this embodiment, the insulating spacer shown by 16 in FIG. 6 is used.

The insulating spacer 16 is formed to have a thickness slightly smaller than the insulating distance, and has a cylindrical shape which is inserted into a recess 17 formed on the inner surface of the mold 4 on the base end side thereof. Is provided with a protrusion 18 (insertion portion). The insulating spacer 16 is inserted into the recess 20 provided in the mold 4 after the Teflon ring 19 is mounted on the protrusion 18 (projection portion), and the Teflon ring 19 is expanded by heating so that the insulating spacer 16 is removed. The inner surface of the mold 4 is crimped and fixed. As a result, a gap having a predetermined size is forcibly formed between the irregularities 9 of the coil body 2 and the bottom of the insulating spacer 16, and contact with the coil body 2 is regulated.

At the time of resin casting, the insulating resin also flows into the gap forcibly formed between the bottom of the insulating spacer 16 and the conductor, so that the insulating resin layer is formed according to the size of the gap. The thickness of the insulating resin layer is appropriately determined according to the applied voltage.

After the insulating resin is cooled and hardened, the Teflon ring 19 contracts, so that the propulsion coil 1 can be easily released from the mold. Further, after the mold release, the tephron ring 19 and the protrusion 18 are cut.

With this structure as well, the contact between the insulating spacer 16 and the unevenness 9 of the wound body 7 can be prevented, so that it is possible to effectively prevent the bubbles generated at the time of resin casting from remaining in this portion. Further, since the insulating spacer 16 is firmly fixed by the teflon ring 19, the insulating spacer 16 can be prevented from falling down.

Next, a fourth embodiment will be described with reference to FIG. In this embodiment, the insulating spacer 16 of the third embodiment is covered with a cap 21 made of heat-shrinkable resin. According to such a configuration, the winding body 7 is covered by the cap 21.
While the (coil body 2) can be held, at the time of casting, the heat-shrink cap 21 heat-shrinks, so that a predetermined gap is forcibly formed between the wound body 7 and the insulating spacer 16. .

Therefore, the same effect as that of the third embodiment can be obtained. Next, regarding the fifth embodiment,
This will be described with reference to FIG. In this embodiment, in the third embodiment, the sheet layer 22 that thermally expands between the bottom portion of the insulating spacer 16 and the wound body 7 (coil body 2).
Is inserted.

According to this structure, at the time of casting, the sheet layer 22 is thermally expanded and the gap between the layers of the sheet layer 22 is impregnated with the insulating resin, so that a strong insulating resin layer is formed. .

Next, FIG. 9 shows the sixth embodiment.
This will be described with reference to (a) and (b). In this embodiment, first, the first layer 3a of the insulating resin mold body 3 is formed using a mold (not shown) having a size smaller than the casting mold used in the first to fifth embodiments. Then, the second layer 3b of the insulating resin mold body 3 is formed by using a mold having the same size as the casting mold 4 used in the first to fifth embodiments. .

When molding the first layer 3a,
The first insulating spacer 23 is used, the second insulating spacer 24 is used when the second layer is formed, and the first and second insulating spacers 2 are formed as shown in FIG. 9B.
3, 24 are arranged so as to be offset from each other.

According to this structure, since the plurality of insulating spacers 23 and 24 are used in the thickness direction of the mold body 3 and these are offset from each other, the winding body 7 (coil body) is used. 2) Distance from the surface to the outer surface of the molded body 3 (outer surface of the second layer 3b) along the outer extension of the first and second insulating spacers 23 and 24 (creeping distance)
Can be increased.

Therefore, even if the bubbles remain at the boundaries between the irregularities 9 of the wound body 7 and the first insulating spacers 23 to cause a minute space after the resin is cured and cause a dielectric breakdown, It is possible to prevent the dielectric breakdown from reaching the outer surface of the second layer 3b. Further, even when bubbles remain at the boundary portion, it is possible to prevent the bubbles from continuing to the second insulating spacer 24 of the second layer 3b.

As a result, it is possible to obtain the propulsion coil 1 exhibiting excellent insulating characteristics and having extremely high reliability. It should be noted that as the first and second insulating spacers 23, 24 are arranged farther apart, the creeping distance between the insulating spacers 23, 24 becomes longer and a propulsion coil having excellent insulating characteristics can be obtained.

The present invention is not limited to the above-described one embodiment, and can be modified within the scope of the invention. For example, in FIG. 1, eight insulating spacers 5 are provided above and below, but the number is not limited to this. Further, it is not necessary for all the insulating spacers to have the same configuration. For example, some of them have the configuration of the first embodiment, and others have the same configuration.
It may have the configuration of the second embodiment.

The surface processing applied to the insulating spacer 5 has been described only in the description of the first embodiment.
Similar surface processing may be performed on the insulating spacers 14, 16, 23 and 24 of the other embodiments. As a result, the insulation characteristics of the propulsion coil 1 manufactured according to each embodiment can be further improved.

Further, in the above embodiment, the propulsion coil 1 used in the magnetic levitation railway has been described as an example, but other insulating resin cast products having the same function, such as a penetration type current transformer, may be used. The present invention can also be applied to electrical equipment that is connected to the outside via a connection terminal.

[0064]

As described above, according to the present invention, it is possible to prevent bubbles generated in the resin from remaining around the insulating spacer in the casting process. As a result, it is possible to prevent a minute gap from being formed at the boundary between the insulating spacer and the conductor after the resin is cured, and thus it is possible to effectively prevent the occurrence of defects such as dielectric breakdown due to the minute gap. is there.

Further, by using a plurality of insulating spacers in the thickness direction of the mold body and further shifting these positions, the creeping distance from the conductor to the outer surface of the mold body can be increased. As a result, it is possible to prevent the bubbles from continuing, and thus it is possible to obtain an insulating resin cast product that is resistant to dielectric breakdown and the like.

[Brief description of drawings]

FIG. 1 is a front view showing a magnetic levitation railway propulsion coil according to an embodiment of the present invention.

FIG. 2 is a vertical sectional view similarly illustrating the first embodiment.

FIG. 3 is a vertical cross-sectional view illustrating a modified example of the first embodiment.

FIG. 4 is a vertical cross-sectional view illustrating another modification of the first embodiment.

FIG. 5 is a vertical sectional view for explaining the second embodiment as well.

FIG. 6 is likewise a vertical cross-sectional view for explaining the third embodiment.

FIG. 7 is likewise a vertical cross-sectional view illustrating a fourth embodiment.

FIG. 8 is likewise a vertical cross-sectional view for explaining the fifth embodiment.

9A is a longitudinal sectional view of the propulsion coil manufactured in the sixth embodiment, and FIG. 9B is a longitudinal sectional view taken along line II-II of FIG. 9A.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Propulsion coil (insulating resin cast product) 2 ... Coil main body 3 ... Insulating resin mold body 4 ... Casting mold 5 ... Insulating spacer 7 ... Conductive band winding body (conductor) 8 ... Insulating tape ( Insulating sheet material, glass tape, non-woven fabric of polyester) 9 ... Roughness 15 ... Projection 17 ... Die 18 provided in the mold ... Insert 19 ... Teflon ring 23 ... First insulating spacer 24 ... Second insulating spacer

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Miwa Jin No. 1 in Toshiba Fuchu factory, Fuchu-shi, Tokyo (72) Inventor Satoshi Makishima No. 1 Toshiba-cho, Fuchu, Tokyo Toshiba Fuchu factory, Co., Ltd. (72) Inventor Masaharu Yasue 1 Toshiba Town, Fuchu-shi, Tokyo Inside Toshiba Fuchu factory (56) References JP-A-6-238680 (JP, A) JP-A-6-134766 (JP, A) JP-A-5-121230 (JP, A) JP-A-4-239704 (JP, A) JP-A-2-168610 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01F 7/20

Claims (18)

(57) [Claims] 1. When holding a conductor requiring ground insulation in a casting mold, an insulating spacer is interposed in the gap between the inner surface of the casting mold and the conductor, and an insulating resin is placed in this gap. By injecting and solidifying, in the method for producing an insulating resin cast product in which the conductor is cast with an insulating resin, in the conductor, in the uneven portion where the insulating spacer faces,
A method of manufacturing an insulating resin cast product, which comprises a step of adhering an insulating sheet material covering the uneven portion. 2. The method for manufacturing an insulating resin cast product according to claim 1, wherein at least a part of the insulating sheet is formed of a material having an affinity with the insulating resin. Manufacturing method of mold. 3. The method for manufacturing an insulating resin cast product according to claim 2, wherein a glass tape is used as the insulating sheet. 4. The method for producing an insulating resin cast product according to claim 2, wherein a polyester non-woven fabric is used as the insulating sheet. 5. The method for manufacturing an insulating resin cast product according to claim 1, further comprising a step of attaching an insulating sheet material to the conductor, impregnating the insulating resin, and heating and curing the insulating resin. Manufacturing method of resin casting. 6. The method for manufacturing an insulating resin cast product according to claim 1, wherein the insulating sheet material is attached after impregnated portions of the conductor are filled with glass fiber, and the insulating resin is impregnated and cured by heating. A method for manufacturing an insulating resin cast product, comprising the steps of: 7. The method of manufacturing an insulating resin cast product according to claim 1, wherein the insulating spacer is an insulating spacer obtained by sandblasting the surface and then subjecting it to a primer treatment with a resin of the same system as the casting resin. A method of manufacturing an insulating resin cast product, comprising: 8. The method for producing an insulating resin cast product according to claim 1, wherein the insulating spacer is sandblasted on the surface and then vacuum-heated to remove trace components adhering to the surface of the insulating spacer. A method of manufacturing an insulating resin cast product, which comprises using an insulating spacer as described above. 9. The method for manufacturing an insulating resin cast product according to claim 1, wherein the insulating spacer is an insulating spacer formed of a material having low water absorption. Method. 10. The method for manufacturing an insulating resin cast product according to claim 9, wherein an insulating spacer made of ceramic is used as the insulating spacer. 11. When holding a conductor requiring ground insulation in a casting mold, an insulating spacer is interposed in the gap between the inner surface of the casting mold and the conductor, and an insulating resin is placed in this gap. A method of manufacturing an insulating resin cast product in which the conductor is cast with an insulating resin by injecting and solidifying, the insulating spacer, as the insulating spacer, at least a part of the surface of the conductor surface facing the uneven portion, the uneven portion A method for manufacturing an insulating resin cast product, which comprises using an insulating spacer provided with a protrusion that abuts against the insulating resin. 12. The method for manufacturing an insulating resin cast product according to claim 11, wherein the protrusion is formed with a size corresponding to a recess or a protrusion of an uneven portion of the conductor. Casting method. 13. When holding a conductor requiring ground insulation in a casting mold, an insulating spacer is interposed in the gap between the inner surface of the casting mold and the conductor, and an insulating resin is placed in this gap. In a method of manufacturing an insulating resin cast product, in which the conductor is cast with an insulating resin by pouring and solidifying, an insulating spacer having a thickness smaller than a distance of the ground insulation is used as the insulating spacer, and the insulating spacer is used. Is fixed to the mold to regulate contact between the insulating spacer and the conductor. 14. The method for manufacturing an insulating resin cast product according to claim 13, wherein an insert portion to be inserted into a recess provided in the mold is provided in a part of the insulating spacer, and a Teflon ring is provided in the insert portion. A method for producing an insulating resin cast product, which comprises a step of fixing the insulating spacer to the mold by inserting it into a recess provided in the mold after the packaging and expanding a Teflon ring by heating. . 15. The method for manufacturing an insulating resin cast product according to claim 13, wherein the insulating spacer is fixed to a mold, the insulating spacer is covered with a heat shrink cap, and the heat shrink cap is heated. A method of manufacturing an insulating cast product, comprising the step of causing a gap between the conductor and the insulating spacer by heat shrinking. 16. The method for manufacturing an insulating resin cast product according to claim 13, wherein a thermally expandable sheet layer is inserted between the insulating spacer and the conductor, the sheet layer is expanded by heating, and the insulating resin is provided between the layers. A method for producing an insulating resin cast product, comprising a step of producing a gap that can be injected. 17. A first insulating spacer is interposed in a gap between an inner surface of the first casting mold and a conductor requiring ground insulation,
A first insulating resin casting step of casting the conductor with an insulating resin by injecting an insulating resin into the gap and solidifying the conductor, and a casting product manufactured in the first insulating resin casting step and a second insulating resin casting step. Interpose the second insulating spacer in the gap between the casting mold of
A second insulating resin casting step of casting the casting product with the insulating resin by injecting an insulating resin into the gap and solidifying the insulating resin, the method for producing the insulating casting product. 18. The method for manufacturing an insulating cast product according to claim 17, wherein the first and second insulating spacers are arranged so as to be displaced from each other. .