JPS59219916A - Manufacture of resin molded coil - Google Patents

Abstract

PURPOSE:To remove leakage of resin, and to stabilize the electric and the mechanical characteristics of a resin molded coil by a method wherein inner peripheral insulators formed of a heat-resistant board are provided on the inner periphery to face with a cooling air path, and moreover nonimpregnatable insulators are provided on the outer periphery, and a heat-shrinkable tape is wound around the edge parts thereof to form heat-shrinkable layers. CONSTITUTION:Insulators 21a-21c consisting of a nonimpregnatable heat-resistant board are provided on the inner peripheral sides of respective coils, and the lap parts of the insulators 21a-21c thereof consisting of the heat-resistant board are sealed. Moreoverm in regard to the outer peripheral sides of the inside coil 10a and the outside coil 10b of a low voltage coil 10, and the inside coil 12a of a high voltage coil 12, nonimpregnatable insulators 19a-19c are provided also. A glass cloth tape is wound round moreover on a nonimpregnatable film 25 formed on the outermost peripheral part of an outside coil 12b to form an insulator layer 26. Moreover, a heat-shrinkable tape is wound around the edge parts of the respective coils to form heat-shrinkable layers 20. According to the process mentioned above, leakage of the impregnated resin can be checked.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for manufacturing a resin molded coil with a multi-winding structure used in electromagnetic induction devices such as dry transformers and reactors.

[Technical background of the invention]

For example, the coil of a mold type dry transformer can be manufactured using a mold or a so-called impregnation type manufacturing method without using a mold.

Among these manufacturing methods, the impregnation type manufacturing method does not use a mold, so it has a high degree of freedom in design and can easily accommodate a wide variety of coils, and the thickness of the resin layer can be easily changed. There is no cracking that is typical of molded coils, and the product can be made smaller and lighter. however,
Since low-viscosity resin is used and no mold is used, the resin impregnated inside the coil may leak out, and the key to the manufacturing method is how to prevent this.

By the way, the conventional method of manufacturing a molded coil using the impregnation type is as follows: (1) Take out a coil impregnated with resin in a resin tank, and then transfer the coil to a rotary drive device so that it can be rotated. (2) A curing accelerator is attached to the inside of the coil or the coil insulation layer in advance, and the resin is impregnated with the resin, and the resin reacts with the curing accelerator to cure the resin. A known method is to take the coil out of the resin tank when the resin in the coil no longer leaks and heat it in a heating furnace to harden the resin.

Of these methods, method (1) above requires work to set the coil in a rotary drive device, and also has the disadvantage that it is not suitable for fertile root species due to equipment limitations of the rotary drive device. Recently, the manufacturing method (2) above has been attracting attention.

Here, the manufacturing method (2) above will be explained with reference to the drawings. FIG. 1 and FIG. 2 show an example of a resin molded coil having a multi-wound structure produced by a conventional manufacturing method.

In order to manufacture a resin molded coil by this conventional method, a conductor 2a is wound around a winding frame 1 such as an insulating tube to constitute a low voltage coil 2, and the upper end of the Hiji wire 2 is shown (Fig. 2). After pulling it out to the side, a glass tube to which a hardening accelerator has been applied in advance is wound around the outer periphery of the low voltage coil 2 to form an insulator 3a around the outer periphery of the low voltage coil 2. On the outside of this insulator 3a, a wave-shaped spaced insulator 4 is arranged to ensure a cooling airway. A curing accelerator was previously attached to the spacing insulator 4, and after winding the lath tape to form the insulator 3b, the conductor 5IL was wound to form the high voltage coil 5, and the lead wire 5b was attached to the upper end. Pull it out to the side. The high voltage coil 5 is formed of a plurality of winding layers with an interstage insulator 6 interposed therebetween.

Therefore, a predetermined distance is maintained between the low voltage coil 2 and the high voltage coil 5 by the spacing insulator 4.

In addition, end insulators 2 are provided at the upper and lower ends of the low-voltage coil 2 and the high-voltage coil 5 to insulate the coils and improve mechanical strength.
7' is inserted, but in this case, the lower end insulator 7' is treated with a curing accelerator in advance. Further, the outermost periphery of the high voltage coil 5 was also treated with a curing accelerator and wound with lath tape to form an outer periphery insulator 3c.

The entire coil is housed in a resin bath (not shown) and impregnated with resin, and this resin becomes the insulator treated with the curing accelerator. a.

3b, 3e, and 7' are left in a resin bath until they are mixed with a curing accelerator. Eventually, the hardening of the insulators 3m, 3b, 3c, and 7' treated with the curing accelerator progresses, and when the resin impregnated inside the coil does not flow out, the coil is removed from the resin bath. The coil was pulled up and then heated in a heating furnace to harden the resin to obtain an integrated resin molded coil.

[Problems with background technology]

However, such conventional molded coil manufacturing methods have the following drawbacks.

That is, in a cylindrical or square tube multiple winding structure, the coil is wound with end insulators 7, 7' arranged at the upper and lower ends of the coil as explained in the conventional example. ' is a conductor of 3m
If the 5 m long bank parting is thin, a gap is likely to form between it and the interstage insulator 6 that extends to the lower end. Further, a wedge-shaped gap corresponding to the thickness is formed in the lap portion of the interstage insulator 6 inserted for each conductor winding layer. On the other hand, a curing accelerator is applied to the lower end insulator 7' in advance, but if several interstage insulators 6 are used in a stacked manner, a curing accelerator is applied to the lower end insulator 7' in advance. The reaction between the agent and the resin causes a lubrication effect on the interstage insulator 6.
This causes the resin to leak to the outside from the interstage insulator 6.

On the other hand, from the perspective of coil winding work, the various gaps that occur at the lower end of the coil vary greatly depending on the winding worker.In a coil that is tightly tightened, the gaps are small, so the resin does not leak outside, and the gaps are loose. Sometimes the resin leaks from various gaps, and the manufacturing method is unstable because there are large differences depending on the individual winding work.

Furthermore, when the coil capacity is large, it is common to provide cooling air passages inside the low-pressure coil and high-pressure coil for cooling purposes, but as mentioned above, the tightening of the lower end of the coil is
Since a gap is created in the tightening at this cooling airway section, resin tends to leak to the outside from the lower end of the coil.

In this way, if the lower end of the coil is tightened, the impregnated resin may or may not leak from the gap created at the lower end of the coil, which may cause a decrease in insulation properties, especially partial discharge, or dielectric breakdown. There is a fear. In addition, in order to prevent this partial discharge from decreasing, leave the coil in the resin bath for a long time to prevent the reaction between the resin in each insulator and the curing accelerator.
The dulling effect progresses and it is possible to prevent leakage of the impregnated resin due to individual differences in the coil winding process, but this will not only slow down the flow of the production process, but also cause the resin in the resin tank to deteriorate over time. The disadvantage is that the pot life is shortened due to the progress of dulling.

[Purpose of the invention]

The present invention has been made to eliminate the above-mentioned drawbacks.
Provided is a method for manufacturing a resin molded coil that is capable of stably impregnating resin without being affected by the degree of coil tightening during coil winding work, and that is electrically and mechanically good without leaking of the impregnated resin. The purpose is to

[Summary of the invention]

In order to achieve such an object, the present invention provides edge insulators on the outer sides of the upper and lower ends of the winding layer in which the conductor is wound, and also provides a heat-resistant material that is difficult to impregnate with resin on the inner periphery of the winding layer facing the cooling airway. −
A coil is provided with an inner circumferential insulator made of aluminum foil, a non-impregnable insulator is provided on the outer circumference, and a heat-shrinkable layer is formed by wrapping a heat-shrinkable tape around the lower end of the coil. After adhering the agent and pre-drying, the coil is impregnated with resin in a resin bath, and when the resin impregnated into the lower end insulator of the coil reacts with the curing accelerator and becomes dull, the coil is removed from the resin bath. It is characterized by being extruded and then heated and cured.

[Embodiments of the invention]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As an embodiment of the present invention, the structure and manufacturing method of a multi-wound coil having a cooling airway inside a resin molded coil will be described below with reference to the drawings. FIG. 3 is a plan view showing an example of the structure of a resin molded coil obtained by the manufacturing method according to the present invention. As shown in Fig. 3, a winding frame 8 made of a cylindrical insulator
A low voltage coil 10 and a high voltage coil 12 are arranged concentrically. The low voltage coil 10 consists of an inner coil 10m and an outer coil 10b.
A corrugated spacing insulator 9a is arranged between the coils 10b to form a cooling airway, and a part of the inner coil 717a is electrically connected to the outer coil 717a and the outer coil 717a ([111]). A crossing section 73a is provided.The high-voltage coil 2 consists of an inner coil 12a and an outer coil 12b, and an insulator 9b having the same waveform as described above is provided between both coils 12a and 12b to cool the airway. and an inner coil 12m and an outer coil 12b are formed in a part thereof.
A crossing section 1 that electrically connects the end of the winding and the beginning of the winding.
There are 3 retakes. A corrugated spacing insulator 1) is also provided between the low voltage coil io and the high voltage coil 12 to form a cooling airway. In this way, each corrugated space insulator 9a is concentrically placed on the winding frame 8.

After resin impregnation and hardening, the low voltage coil 10 and the high voltage coil 12 wound through the coil 11.9b are firmly fixed with resin to form an integrated resin molded coil. Note that the winding start end of the inner coil 10h of the low voltage coil 10 and the outer coil 10
Generally speaking, each exposed portion 14 at the winding end υ end of b, the winding start end of the inner coil 12m of the high voltage coil 12, and the winding end end of the outer coil 12b is connected to the low voltage coil 10 as shown in FIG. Although it is located on the opposite side to the high voltage coil 12, it may also be located in the same direction.

Next, a method for manufacturing a resin molded coil will be described with reference to a sectional view of the main parts shown in FIG.

First, a winding frame 8 made of a cylindrical insulator is mounted on a winding form of a winding machine (not shown), and then a highly impregnable material such as a nonwoven fabric is wound on this winding frame 8 to form an insulator J5h. form. Examples of the highly impregnable material include aramid nonwoven fabric, polyester nonwoven fabric, glass mat, and glass cloth tape.

Thereafter, end insulators 16 and J6' made of highly impregnable rock wool, mineral fiber, aramid nonwoven fabric, etc. are placed at the upper and lower ends of the 15 m insulator, and an insulating coating is placed between the end insulators 16 and 16'. The inner coil 10a is formed by winding the conductor 77a which has been subjected to the thinning process.

Here, since there is a transition part 13a on the outer side of the inner coil 10a, a sheet-like easily impregnable material is wound around the outer peripheral surface of the inner coil 10a to form an insulating material 78m, and a non-impregnable material is further placed on top of the insulating material 78m. Thin leaf material (for example, product name: Devon 4)
101-MEX, Nippon Aroma GAH, etc.) is wound to form an insulator 19h. At this time, the part 13a of the bridge 9 is sealed with a silicone room-temperature vulcanized rubber or the like to seal the part coming out of the coil 10a, and an insulator 19a made of a non-impregnable thin material is used.
Also seal the wrap part with silicone room-temperature vulcanized rubber or adhesive tape. After that, the insulator 19a made of the thin material
A heat-shrinkable layer 20 is formed by wrapping a heat-shrinkable tape several times only around the lower end of the coil. This heat-shrinkable tape is a heat-shrinkable film (product name: Toshi's heat-shrinkable Lumirror).
, polyester-mixed aromatic polyamide nonwoven fabric (trade name HX-0205 manufactured by Nippon Vilene Co., Ltd.), polyester nonwoven fabric, and the like.

Next, after disposing and fixing a corrugated spacing insulator 9a for forming a cooling airway around the outer periphery of the insulator 19m, an insulator 2Ja made of non-impregnable heat-resistant z-p is provided. Is this heat resistant? Examples of the laminate include Nippon Aro'V's GA, FR-D (trade name), and epoxy glass laminate. At this time, the ferry section 1
3a or heat resistant? The 7'' section of the 21 m insulator consisting of - is sealed by applying silicone room-temperature hot-flow rubber or the like.

On the insulator 21h made of this heat-resistant date, a sheet-like easily impregnable feather similar to that described above was wound to form an insulator 18b, and on top of that, end insulators 16 and 16' were arranged at the lower end. After that, the conductor 17b is wound in between to form the outer coil 10.
form b.

The outer circumferential surface of the outer coil 10b is coated with an easily impregnable material in the same manner as the outer circumferential surface of the inner coil 10m.
8c, a non-impregnable thin sheet material is wound thereon to form an insulator 19b, and a heat-shrinkable tape is wrapped several times around the lower end of this insulator 19b to form a heat-shrinkable layer 20.

Next, after arranging and fixing a corrugated spacing insulator 1 for maintaining the main insulation spacing around the outer periphery of the low voltage coil 10 formed in this way, an insulator 21b made of a heat-resistant board is placed on top of it. An insulator 15b is formed by winding an easily impregnable material thereon, and a high voltage coil J2 is also wound around the outer periphery of the insulator 15b in the same manner as the low voltage coil 10. That is, FIG. 5 shows a cross section of the lower end of the inner 1 coil 12a of the high voltage coil 12, and FIG. 6 shows the outer coil 12b of the high voltage coil J2.
This is a cross-sectional view of the lower end. As shown in FIGS. 4 and 5, end insulators J 6 are provided at the upper and lower ends of the insulator 15b formed on the insulator 2Ib having a heat resistance of -.
, 16' are arranged and fixed, a conductor 17c having an insulating wave υ is wound therebetween to form an inner coil J2a. In this case, since the high-voltage coil 2 generally has a larger number of turns than the low-voltage coil io, the inner coil 12g is formed with multiple layers (the figure shows the case of two layers), and between the layers there is a An insulator 22a (eg, aramid nonwoven fabric, etc.) is inserted. A sheet-like easily impregnable material is wound around the outer circumferential surface of the inner coil 12m in the same manner as that wound around the outer circumferential surface of the inner coil 10m of the low voltage coil 10.
8c, a non-impregnable material is wound thereon to form an insulator 19c, and a heat-shrinkable tape is wound around only the lower end of this insulator 19c to form a heat-shrinkable layer 20. Next, after disposing and fixing the additional corrugated interval insulator 9b for forming a cooling airway around the outer periphery of the insulator 19c, the outer coil 12b is wound up in the same manner as the outer coil 10b of the low voltage coil 10. That is, as shown in FIGS. 4 and 6, an insulator 21c made of a non-impregnable heat-resistant board is wrapped around the outer periphery of the wavy insulator 9b. A sheet-like easily impregnable insulating material is wound to form an insulator 18d, and an end insulator 16° 16' is placed on the lower end thereof, and then an insulated conductor J7d is wound between them. Then, the outer coil 12b is formed. In this case, the outer coil 12b is formed in two layers like the inner coil 12m, and an interlayer insulator 22b is inserted between the layers. The outer periphery of the outer coil 12b wound up in this manner may have the same structure as the outer periphery of the inner coil 12m if there is no voltage switching device, etc., but since a voltage tag is generally provided, a sheet-like structure may be used. In the case of insulating material, holes must be made, so it is made of tape-shaped insulating material.

First, an easily impregnable material such as glass cloth tape or nonwoven tape is wound around the outer peripheral surface of the outer coil j2b to form the insulator 24.
Forms a layer on which it is difficult to impregnate and adhere with resin:
Apply leaf insulation tissue (e.g., product name: Nomex 410 type, GAH, A tissue made by Nippon Aroma, etc.).
The non-impregnated film 25 is formed by winding it around once. Furthermore, a glass cloth tape with a curing accelerator stuck thereon is wound to form an insulator 26, and then a heat shrink tape is wound around the outer peripheral surface of the lower end to form a heat shrink layer 20.

The low-voltage coil No. 0 and high-voltage coil No. 2 wound in this way are pre-dried after a curing accelerator is applied to their lower ends, and then the coils are placed in a resin bath in a vacuum pressurized tank (not shown). Then, vacuum and pressure impregnate it with epoxy resin, etc.

Then, while the coil remains in the resin bath, the lower end outer circumferential surface 16' to which a curing accelerator has been applied in advance and the insulator 26 formed by the glass cloth tape react with the impregnated resin and become glued. At that point, remove the coil from the resin tank,
The resin completely impregnated inside the coil is cured in a dryer or the like, and a resin molded coil in which a low voltage coil and a high voltage coil are integrated is obtained as shown in FIG.

By obtaining a resin molded coil by such a manufacturing method, the following effects can be obtained. That is, in a resin molded coil, it is important to impregnate the coil with resin and to prevent the impregnated resin from leaking to the outside.

Therefore, if any of these is insufficient, insulation defects such as unimpregnated areas or voids due to leakage will occur inside the coil, resulting in a decrease in partial discharge voltage and dielectric strength, and there is a risk of dielectric breakdown of the coil. be. Therefore, in this embodiment, when impregnating with resin, the insulator 15a is provided on the side facing each coil conductor.

15b, 188 to 8d, 24 and interlayer insulator 22m,
An easily impregnable insulating material is used as 22b, and end insulators 16, 16' are provided at the upper and lower ends of each coil.
Also, a material with good impregnation properties is used so that the resin is impregnated from the upper and lower ends of the coil in the axial direction. In this case, the impregnation distance varies depending on the degree of vacuum, pressure, and time during resin impregnation, but according to experiments, after putting io o o cp of epoxy resin into a resin bath in a vacuum of 1 wnHg, 5
700m when pressurized for 30 min at kg/crn
It was found that even the stack was sufficiently impregnated.

On the other hand, in terms of leakage of the impregnated resin to the outside, as explained in the conventional example, there is a risk of loosening of the insulator, gaps forming at the lap part, butting part of the end insulator, etc. If the coil is pulled out of the resin bath at the point when the curing accelerator reacts with the impregnated resin and becomes glued, the impregnated resin may leak to the outside. On the other hand, in this embodiment, an insulator 21a made of a non-impregnated thermal board is provided on the inner peripheral side of each coil.
~21cf: Is this heat resistant as well as installed? Since the lap portions of the insulators 21a to 21c made of - cord are sealed, the impregnated resin will not leak from this surface from the outside. Also, the inner coil 10I of the low voltage coil No. 0! L, outer coil yv l Ob, non-impregnable insulator 19a~ for the outer circumferential surface of the inner coil 12m of the pressure coil No. 2.
19c, the impregnated resin will not leak to the outside from this surface as well. Furthermore, since the outermost periphery of the outer coil 12b of the high-voltage coil 12 is wrapped with a thin film anti-resuscitation tape made of a non-impregnable material to form a non-impregnated film 25, the tape and the wrap portion of the tape may leak the impregnated resin. However, since the insulator 26 is formed by winding a glass cloth tape coated with a curing accelerator on top of the tape, the wrap portion of the non-impregnated insulating tape is pressed down.
Then, it reacts with the resin in the resin bath and undergoes lubrication, forming a sealing layer together with the non-impregnated film 25. Therefore, the impregnated resin is prevented from leaking to the outside from the inner and outer circumferential surfaces of each coil. On the other hand, regarding the lower end of each coil, depending on the method of coil winding, there may be a slight gap between the lower end of each coil and the end insulator. Since the shrink layer 20 has not yet been formed, this heat shrink layer 20 is only 1% of the total at the time of pre-drying.
~ 2 degrees of shrinkage occurs, and when the coil is taken out of the resin bath and placed in a drying oven, it shrinks further and squeezes the lower end insulator 16', and at the same time, a gap is created due to the progress of ruching at the lower end due to the curing accelerator. Since it is filled with resin, leakage of the impregnated resin from this part can be prevented. According to experiments, heat shrinkable Lumirror Tape (trade name) made by Toshi (0,025t x 25
Width) is wrapped three times and pre-attached using IB2MZ (trade name) made by Shikoku Kasei as a curing accelerator, epoxy resin Ep828 (trade name) made by Shell Co. as the impregnating resin and acid anhydride curing agent made by Hitachi Chemical. Using HN-2200 (product name),
After pre-drying for 1001: x 15 hours, vacuum pressure impregnation with impregnating resin at 80°C is carried out, and when the resin is immersed up to the top of the coil, it is left for 1 to 2 hours, and then the coil is taken out and heated to 120°C to 150°C. When the coil was placed in a drying oven and cured, a stable resin-molded coil with good insulation properties was obtained without any resin leakage.

By wrapping the heat-shrinkable tape around the lower end of the coil to form the heat-shrinkable layer 20, the gap at the lower end that occurs at the time of winding the coil can be heat-shrinked during the resin treatment process from pre-drying to curing. There is no damage due to the shrinkage of the layer 20,
Stable resin molded coils can be manufactured.

In addition, in the above embodiment, a case was explained in which the low-voltage coil and the high-voltage coil are prevented from flowing out of the impregnated resin with respect to a cylindrical coil in which the low-voltage coil and the high-voltage coil are arranged concentrically. If prevention is not necessary, biopsy to prevent resin outflow may be performed only on the high-voltage coil (9), and the low-voltage coil may have the same configuration as the conventional one. Further, in the above-mentioned example 1', a transformer having a low-voltage coil and a high-voltage coil was explained, but the present invention can also be applied to a transducer or the like.

In addition, the same method can be used for rectangular tubes with the same multi-winding configuration as in the above example, and C can be used to manufacture resin molded coils with the same configuration (O) even when there are multiple cooling airways in the coil. Needless to say.

〔Effect of the invention〕

As described above, according to the present invention, an inner circumference insulator formed of a heat-resistant board is provided on the inner circumference facing the cooling airway of a wound layer formed by winding eight bodies, and a non-impregnable insulator is provided on the outside. A coil is prepared by wrapping a heat-shrink tape around the end of the coil to form a heat-shrink layer, and a curing accelerator is added to the bottom end of the coil, and after pre-drying, it is impregnated with a resin. Since the coil is heated and cured once it reacts with the curing accelerator and becomes rubberized, there is no instability of the impregnated resin due to differences in the degree of tightening during coil winding work, and there is no leakage of the impregnated resin. It is possible to create a resin molded coil that is electrically and mechanically stable without any problems. Furthermore, in the past, gaps at the bottom end of the coil, etc., were inspected and repaired in order to eliminate leakage of the impregnated resin, but with the present invention, these efforts can be omitted, and the coil can be immersed in the resin bath for a long time. Since there is no need to store the resin, there are great economical benefits such as extending the useful life of the resin in the resin tank.

[Brief explanation of the drawing]

1 and 2 are plan views and partially sectional front views showing a resin molded coil produced by a conventional manufacturing method, and FIGS. 3 and 4 show an embodiment of a resin molded coil produced by the manufacturing method of the present invention. A plan view, a partially sectional front view, and FIGS. 5 and 6 are sectional views showing the main parts of FIG. 4, respectively. 8... Winding frame, 9a, ! ? b, 11... Spacing insulator, 10... Low voltage coil, JOa... Inner coil, Ob... Outer coil, J2... High voltage coil, 1
2h...Inner coil, 2b...Outer coil, 13
Il, j3b...Watashi line, 14...Exit part, 15
m, 15b... Absolute material made of easily impregnable material, 16
, l6'... end insulator, 17a to 17d...
- Conductor, 18a to 18d... Insulator made of easily impregnable material, 19a to j9e... Insulator made of traceable material,
20... Heat-shrinkable layer, 21a to 21c... Insulator formed of heat-resistant board, 22 a + 22 b... Interlayer insulator, 24... Easily impregnable insulator, 25... Non-containing material. Impregnated film, 26...insulator. Applicant ('J Patent Attorney Takeshi Suzue Figure 1 Figure 2Wi Figure 3 4 Figure 411 Figure 5 Figure 6

Claims (1)

[Claims] End insulators are provided outside the upper and lower ends of the winding layer in which the conductor is wound, and an inner peripheral insulator made of a heat-resistant material that is difficult to impregnate with resin is provided on the inner periphery of the winding layer facing the cooling airway. A coil is provided, and a non-impregnable insulator is provided on the outer periphery, and a heat shrink layer is formed by wrapping a heat shrink tape around the lower end of the coil.
A curing accelerator is attached to the lower end of the coil and after preliminary drying, it is impregnated with resin in a resin bath, and when the resin impregnated into the lower end insulator of the coil reacts with the curing accelerator and turns into a A method for producing a resin molded coil by taking out the coil from the resin bath and curing it by heating.