CN-117203285-B - Insulating varnish composition, insulating varnish cured product, coil, and method for producing coil

Abstract

The insulating varnish composition comprises a thermosetting resin (15) which contains at least 1 resin out of unsaturated polyester resins, epoxy resins and vinyl ester resins containing a high molecular weight body having a weight average molecular weight of 2000 or more, and a liquid bubble forming component having a vapor pressure of 1mmHg or more and 80mmHg or less in a standard state of a gas.

Inventors

• Seiyue Wenyan

Assignees

• 三菱电机株式会社

Dates

Publication Date

20260508

Application Date

20210513

Claims (4)

1. 1. An insulating varnish composition characterized by comprising: A thermosetting resin comprising at least 1 resin among an unsaturated polyester resin containing a high molecular weight body having a weight average molecular weight of 2000 or more, an epoxy resin and a vinyl ester resin, and A bubble forming component of the liquid, a vapor pressure of the liquid in a standard state of a gas thereof being 5mmHg or more and 40mmHg or less, The standard state of the gas is a condition in which the reference temperature is set to 25 ℃, the standard pressure is set to 100kPa, The thermosetting resin comprises a polymerization initiator having a 1-minute half-life temperature of 180 ℃ or less, The bubble forming component is a liquid containing at least 1 of a ketone solvent, an ester solvent, an alcohol solvent, a phenol solvent, and an amide solvent.
2. 2. A cured insulating varnish which is obtained by curing the insulating varnish composition according to claim 1, characterized in that, The average diameter of the bubbles contained in the cured insulating varnish is in the range of 0.1-10 [ mu ] m.
3. 3. A coil, comprising: An electric wire wound around the stator core, and The cured insulating varnish of claim 2, wherein gaps between adjacent wires are filled.
4. 4. A method for manufacturing a coil according to claim 3, comprising: An impregnating step of impregnating the coil with the insulating varnish composition according to claim 1, and And a heat curing step of heating the insulating varnish composition impregnated in the coil to cure the insulating varnish composition.

Description

Insulating varnish composition, insulating varnish cured product, coil, and method for producing coil Technical Field The present invention relates to an insulating varnish composition, an insulating varnish cured product obtained by curing the insulating varnish composition, a coil having the insulating varnish cured product, and a method for manufacturing the coil. Background Conventionally, a rotary machine such as a motor, a generator, or a compressor has a coil formed by winding an electric wire around a stator core. In the coil described above, in order to secure electrical insulation of the coil, protect the wire, and fix the wire to the stator core, self-welding of the wire, molding resin forming, insulating varnish treatment, and the like are performed. Among them, in the insulating varnish treatment, it is necessary to impregnate an insulating varnish composition in a gap between wires of a coil, and thus an insulating varnish composition containing a thermosetting resin having a low viscosity is widely used. The insulating varnish composition is required to have impregnability into gaps between wires of a coil. On the other hand, it is required to prevent dielectric breakdown caused by partial discharge occurring between wires of a coil in a cured insulating varnish product produced by curing the insulating varnish composition by heating. As a method for suppressing occurrence of partial discharge between wires of a coil, generally, thickening of an insulating coating layer of the wire and increase of a distance between wires are effective, but there is a possibility that the output of a rotary machine is reduced. As a technique for suppressing the occurrence of partial discharge between electric wires of a coil without causing a decrease in the output of a rotary machine, a technique has been developed in which bubbles are formed in an insulating varnish cured product to reduce the relative dielectric constant of the insulating varnish cured product and to increase the partial discharge initiation voltage (PDIV: PARTIAL DISCHARGE InceptionVoltage) of the insulating varnish cured product. For example, patent document 1 discloses a technique of adding a microcapsule-type foaming agent to a thermosetting resin to obtain an insulating varnish cured product containing air bubbles. Patent document 1 Japanese patent laid-open No. 2020-33433 Disclosure of Invention The larger the size of the air bubbles contained in the insulating varnish cured product, the more likely partial discharge occurs in the air bubbles, and thus the more likely the insulating varnish cured product is to be broken by insulation. However, in patent document 1, since miniaturization of the air bubbles is not considered, there is a possibility that the effect of suppressing the occurrence of partial discharge in the air bubbles is insufficient. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an insulating varnish composition capable of suppressing occurrence of partial discharge of bubbles in an insulating varnish cured product. In order to solve the above problems and achieve the object, the insulating varnish composition of the present invention comprises a thermosetting resin comprising at least 1 resin among an unsaturated polyester resin containing a high molecular weight body having a weight average molecular weight of 2000 or more, an epoxy resin and a vinyl ester resin, and a bubble forming component of a liquid having a vapor pressure of 5mmHg or more and 40mmHg or less in a standard state of a gas, and the thermosetting resin comprises a polymerization initiator having a 1-minute half-life temperature of 180 ℃ or less. ADVANTAGEOUS EFFECTS OF INVENTION According to the present invention, the occurrence of partial discharge of bubbles in the cured insulating varnish can be suppressed. Drawings Fig. 1 is a cross-sectional view of the rotary machine according to embodiment 1 taken along a central axis. Fig. 2 is a cross-sectional view of the rotary machine according to embodiment 1 taken in a direction perpendicular to the central axis, and is a partially enlarged cross-sectional view showing the stator. Fig. 3 is an enlarged partial cross-sectional view schematically showing a cured product of an electric wire and an insulating varnish according to embodiment 1. Detailed Description Next, an insulating varnish composition, an insulating varnish cured product, a coil, and a method for manufacturing a coil according to an embodiment will be described in detail with reference to the drawings. Embodiment 1. Fig. 1 is a cross-sectional view of a rotary machine 1 according to embodiment 1 taken along a central axis C. The rotary machine 1 has a stator 2, a rotor 3, a shaft 4, a frame 5 and 2 brackets 6. The stator 2 is formed in a cylindrical shape based on a central axis C. In the following description of the respective components of the rotary machine