JP2645093B2 - Manufacturing method of heat-resistant insulated wire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to the heat resistance of electric equipment used at a high temperature of 300 ° C. or more, such as an electromagnetic pump for circulating liquid sodium in a fast breeder reactor. The present invention relates to an insulated wire loop and a manufacturing method thereof.

(Prior art) Heat-resistant insulated wires that can be used at a high temperature of 300 ° C. or higher are hardly known. A heat-resistant insulated wire filled with magnesium oxide powder between a conductor and a metal sheath, such as an MI cable (made by Furukawa Electric Co., Ltd.), is known. In addition, since the space factor of the conductor is low, it is not suitable for a wire loop of an electric device having a large capacity.

Also, Japanese Patent Publication No. 62-1241 and Japanese Patent Publication No. 62-1242 disclose that a silicone resin or a silicone resin and a high melting point resin are used in at least a part of the gap between the coils and the outer surface of the coil. A heat-resistant insulated coil is described in which an inorganic layer is formed by filling and / or coating an inorganic powder and then firing.

Further, JP-B-62-57086 and JP-B-62-57087 disclose a coil formed by winding a conductor on an inorganic insulating layer or a heat-resistant insulated wire that becomes inorganic at high temperatures such as abnormalities during use. A method of manufacturing a heat-resistant insulating coil device relating to the method is described.

(Problems to be Solved by the Invention) Since the heat-resistant insulated wire described in these known examples has a powdered inorganic layer formed on the surface, the powdered inorganic layer that is exposed when used for a long period of time is exposed. However, it gradually becomes powdered, falls off and falls apart, and cannot be used for a long period of time. Further, since a too thick inorganic layer cannot be formed, the dielectric breakdown voltage is low, so that it cannot be used for high-voltage equipment.

Therefore, insulated wires used at high temperatures of 300 ° C or higher, such as liquid sodium immersion type uncooled electromagnetic pumps for liquid sodium circulation in fast breeder reactors, can be used stably at high temperatures of 300 ° C or higher for a long time. It is required to have heat resistance and to increase the space factor of the conductor to reduce the size of the insulated wire itself and the electromagnetic pump. Large capacity machines require high voltage insulated wire loops.

The present invention has been made in order to meet such a demand, and can be used stably for a long time at a high temperature of 300 ° C. or more,
An object of the present invention is to provide a heat-resistant insulated wire that can be used even at a high voltage and a method for producing the same.

[Configuration of the invention]

(Means for Solving the Problems) That is, the heat-resistant insulated wire loop of the present invention has a mica tape surface obtained by laminating an insulated conductor surface and an inorganic reinforcing material and mica with an inorganic silicone or an inorganic adhesive. A heat-resistant inorganic material obtained by winding the mica tape around the conductor while applying an inorganicized silicone or an inorganic paint containing an inorganic filler to the material, and further applying an inorganicized silicone or an inorganic adhesive around the conductor. It is manufactured by winding a prepreg insulating tape made of a woven fabric of a fiber and firing it at a high temperature of 300 ° C. or more.

Here, as the inorganic filler, alumina (Al
₂ O _3), magnesia (MgO), silica (SiO _2), zirconia (ZrO _2), steatite (MgSiO _3), clay, kaolin, mica powder, include high melting glass frit or the like. The average particle size of these fillers is preferably 10 μm or less for easy mixing with the mineralized silicone and easy application.

Inorganic silicone is a general term for silicone which is made inorganic by firing at a high temperature. Examples thereof include alkyl silicate silicone AY49-208 (trade name, manufactured by Toray Silicone Co., Ltd.) and borosiloxane paint SMR-1 containing an inorganic filler.
09 (trade name, manufactured by Showa Densen Densha Co., Ltd.) and YR3286 (trade name, manufactured by Toshiba Silicone Co., Ltd.), a pressure-sensitive adhesive composed of methylpolysiloxane.

Examples of the inorganic paint include phosphates such as aluminum monophosphate and silicon phosphate, colloidal silica and colloidal alumina.

If a large amount of an inorganic filler is added to the mineralized silicone, it is generally thermally stable and the price is low. But,
Since the filler itself does not bond by firing, it is necessary to mix the mineralized silicone to such an extent that a strong bond is formed by firing. On the other hand, it is necessary to select the compounding ratio of the inorganic filler and the mineralized silicone so that the composition is not difficult to apply and does not become brittle after firing. Usually, the content of the inorganic filler is preferably about 10 to 90% by weight.

(Function) Here, the mica tape is used because mica has high heat resistance and is excellent in dielectric breakdown voltage and withstand voltage. The reason why the mica tape is used near the conductor is that the electric field is higher near the conductor, and the life can be extended by placing a material having high withstand voltage.

Since mica tape has excellent electrical properties but poor mechanical strength, wrap a prepreg insulating tape made of woven fabric of inorganic fiber with high mechanical strength and heat resistance from above mica tape with poor mechanical strength. By pressing,
Mica tape can be prevented from falling apart.

Winding and baking mica tape or prepreg insulating tape while applying mineralized silicone containing inorganic filler or inorganic paint fills the gaps between the tapes and adheres the conductor and mica tape and tape to each other This is because a strong insulating layer can be formed. There are methods such as vacuum impregnation to fill the voids in the insulating layer, but mineralized silicone containing inorganic fillers or inorganic paints have high viscosity and are difficult to impregnate between tapes, so apply This is because, after all, an insulated wire loop having higher heat resistance can be obtained.

The wrapping of the prepreg insulating tape on the surface is performed by applying a mineralized silicone or an adhesive to the space of the inorganic fiber woven fabric to form a prepreg, so the inorganic filler containing the inorganic filler previously applied between the mica tapes Insulation with excellent insulation properties, while preventing the activated silicone or inorganic paint from flowing out of the space of the inorganic fiber woven fabric wound on the surface, and firmly bonding between prepreg tapes or between prepreg tape and mica tape. This is because a wire loop can be obtained.

In the heat-resistant insulated wire of the present invention, the operating temperature is 30 ° C.
When used at a high temperature of about 0 ° C., soft mica is better than hard mica. This is because hard mica has a lower crystallization water release temperature and softer heat resistance than soft mica. Fig. 3 shows the mica winding insulation at high temperature.
An example of the result of the voltage application life test at 5 kV / mm shows that the soft mica tape wound insulation A is superior to the hard mica wound insulation B at a higher temperature at higher temperatures. The base material of the prepreg insulating tape wound on the surface is electric glass (E
Glass) should be avoided at 600 ° C, as its strength is significantly reduced.

Further, the conductor used in the present invention may be a conductor itself without an insulating coating or an insulated wire having an insulating coating.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

Example 1 In FIG. 1, a rectangular wire made of nickel-plated alumina dispersion strengthened copper 5 (trade name: Glidcop AL-15 manufactured by Glidden Metal Co., Ltd.) was coated with a glass cloth having a thickness of 35 μm and a thickness of 100 mm.
A conductor 1 having a mica tape 2 formed by laminating a soft non-fired mica sheet having a thickness of μm and a small amount of silicone (for example, YR3286 of Toshiba Silicone Co., Ltd.) as an adhesive is wound into a pancake shape, and then an inorganic filler is added. Using an inorganic adhesive 6 such as an alkyl silicate-based inorganic silicone (trade name: AY49-208, manufactured by Toray Silicone Co., Ltd.) containing alumina or the like. Further, a 35-μm-thick glass woven fabric is reinforced with a 100-μm-thick non-fired soft laminated mica from above, and the above-mentioned inorganic filler-containing inorganic silicone (AY49-208) and inorganic filler-containing borosiloxane A mica tape 3 coated with a base resin paint (trade name: SMR-109, manufactured by Showa Densen Densha Co., Ltd.) and a silicone pressure-sensitive adhesive (trade name: YR3286, manufactured by Toshiba Silicone Co., Ltd.) is applied to an inorganic silicone containing the above inorganic filler ( AY49-208) to the insulated conductor 1
It was wound while being applied on the surface and the mica tape 3 surface.
Further, from above, a mineralized silicone (AY49-208) containing the above-mentioned inorganic filler was added to a woven fabric of a fiber ceramic fiber for ultra-high temperature (trade name: Nextel manufactured by 3M Co., USA) comprising three components of alumina, boron oxide and silica. And a borosiloxane-based resin paint (SMR-109) containing an inorganic filler and a prepreg insulating tape 4 made of an inorganic fiber woven fabric obtained by drying and applying an inorganic mineralized silicone (AY49-208) containing the inorganic filler. While winding, an insulating layer was formed.

A polytetrafluoroethylene tape (not shown) for release is wound around the outside of the insulating layer thus formed,
After applying an iron plate, a heat-shrinkable polyester tape (which may be in the form of a film, a tube, or a woven fabric) is wrapped, and wrapped at 80 ° C for 1 hour, 130 ° C for 2 hours, and 150 ° C for 2 hours.
And cured for another 15 hours at 180 ° C. Thereafter, the heat-shrinkable polyester tape, iron plate, and polytetrafluoroethylene tape for release were removed, and the wire was baked in air at 300 ° C. for 8 hours and at 600 ° C. for 8 hours to obtain a heat-resistant insulated wire. I got

In the above manufacturing process, pressure during heat curing is performed by heat shrinkage of a heat-shrinkable polyester tape, and furthermore, by heating and baking at a high temperature, organic components contained in the insulating layer are scattered and disappear to become inorganic (ceramic). And a strong inorganic insulating layer was formed.

Example 2 As shown in FIG. 2, as a conductor 1, a 5 mm thick nickel-plated alumina dispersion strengthened copper 5 having a circular cross section of 1.3 mm in diameter (Glid cop AL-1 manufactured by Glidden Metal Co., Ltd.)
5) The round wire consisting of alumina, boria oxide and silica
A yarn of ceramic fiber 7 for high temperature composed of the components (NEXTEL, trade name, manufactured by 3M, USA) is wound, and borosiloxane resin paint 8 (trade name, AMR-109, manufactured by Showa Densen Cable Co., Ltd.) containing inorganic filler is further applied thereon. A heat-resistant insulated wire 9 formed by applying and baking at 485 ° C. to form a baked coating of insulating paint is coated with mineralized silicone 10 containing an inorganic filler.
(Toy Silicone Co., Ltd., trade name: AY49-208) was applied while applying multiple turns and applying heat.

 Thereafter, a heat-resistant insulated wire loop was manufactured in the same manner as in Example 1.

When the heat-resistant insulated wire obtained as in Examples 1 and 2 was filled with nitrogen and used for a sodium circulation pump of a fast breeder reactor operated at 600 ° C., the breakdown voltage was not changed after one year. It was 80% or more in the initial stage, and it was confirmed that it could withstand long-term use at a high temperature of about 300 to 600 ° C.

〔The invention's effect〕

As described above, according to the present invention, after winding the mica tape having excellent electrical properties and heat resistance on the inner layer in contact with the conductor, mechanical reinforcement from above, heat resistance having excellent heat resistance Since a tape made of a woven fabric of conductive inorganic fibers is wound, a heat-resistant insulated wire excellent in electric and mechanical properties can be obtained. The heat-resistant insulated wire of the present invention can maintain good electrical insulation properties over a long period of time with almost no deterioration in performance even when used at a high temperature for a long period of time.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a heat-resistant insulated wire showing one embodiment of the present invention, FIG. 2 is a cross-sectional view showing another embodiment of the present invention, and FIG.
The figure is a comparison diagram of the charging life characteristics of soft mica tape wound insulation and hard mica tape wound insulation at high temperatures. DESCRIPTION OF SYMBOLS 1 ... Conductor, 2, 3 ... Mica tape 4 ... Pre-preg insulating tape made of inorganic fiber woven cloth 5 ... Nickel-plated alumina dispersion strengthened copper 6 ... Mineralized silicone or inorganic adhesive 7 ... Ceramic fiber for high temperature 8: Borosiloxane resin paint containing inorganic filler 9: Heat-resistant insulated wire 10: Mineralized silicone containing inorganic filler

Claims (1)

(57) [Claims] An inorganic silicone or inorganic paint containing an inorganic filler is applied to a surface of an insulated conductor or a surface of a mica tape obtained by laminating an inorganic reinforcing material and mica with an inorganic silicone or an inorganic adhesive. While winding the mica tape around the conductor, and further winding a prepreg insulating tape made of a heat-resistant inorganic fiber woven fabric coated with an inorganic silicone or an inorganic adhesive around the mica tape, A method for producing a heat-resistant insulated wire, characterized by firing at a high temperature of 300 ° C or higher.