JP2021170480A - Multilayer insulated wire for transformer - Google Patents

Abstract

To provide a multilayer insulated wire for transformer which is used in a transformer in an inverter, and has high heat resistance, voltage resistance and flexibility.SOLUTION: An insulated wire 10 is used in a transformer for an inverter having a conductor 1 and an insulated film 2 provided on outer periphery of the conductor 1, in which the insulated film 2 has two or more fluorine resin layers 2A and 2B that are extruded and laminated. The two or more fluorine resin layers 2A and 2B are preferably the same material, in the case of the two fluorine resin layers 2A and 2B, preferably, a thickness of the first layer is within a range of 0.02-0.06 mm, and a thickness of the second layer is within a range of 0.02-0.06 mm.SELECTED DRAWING: Figure 1

Description

The present invention relates to a multi-layer insulated wire for a transformer, and more particularly to a multi-layer insulated wire for a transformer having high heat resistance, withstand voltage and flexibility, which is used for a transformer or the like in an inverter.

Hybrid vehicles, electric vehicles, and the like are equipped with a motor drive device having an inverter. An inverter is a device that switches at several kHz to several tens of kHz, generates a surge voltage for each pulse, and changes the rotation speed of the motor to drive the inverter. Examples of devices equipped with an inverter include electric devices such as high-speed switching elements, inverter motors, and transformers. These electric devices have a coil using an insulated electric wire made of an enamel wire.

Such a coil receives nearly twice the output voltage. When a high voltage is applied to the coil, partial discharge (corona discharge) is likely to occur on the surface of the insulating coating constituting the insulated wire. The occurrence of partial discharge tends to cause a local temperature rise and the generation of ozone, etc., and as a result, there is a problem that the insulating coating deteriorates and the life of the insulated wire and the motor made of the insulated wire is shortened. It was happening.

In order to increase the partial discharge start voltage, for example, in Patent Document 1, at least one thick film enamel baking layer and at least one extruded coating resin layer are provided on the outer periphery of a conductor having a rectangular cross section. Insulated wires have been proposed. Further, as in Patent Documents 2 and 3, it is also proposed that the insulating film is made of a low dielectric constant material such as fluororesin.

Japanese Unexamined Patent Publication No. 2008-226853 JP-A-2010-284895 Japanese Unexamined Patent Publication No. 2014-32885

However, if the above-mentioned insulating film is thickened or formed of a fluororesin, the flexibility tends to deteriorate. In particular, insulated wires used in transformers for inverters used in hybrid vehicles and electric vehicles are required to have high withstand voltage and flexibility as well as heat resistance because cracks do not occur at bent portions to reduce the withstand voltage.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a multi-layer insulated wire for a transformer having high heat resistance, withstand voltage and flexibility, which is used for a transformer or the like in an inverter. To provide.

The multi-layer insulated wire for a transformer according to the present invention is an insulated wire used for an inverter transformer having a conductor and an insulating coating provided on the outer periphery of the conductor, and the insulating coating is two layers extruded and laminated. It is characterized by having the above-mentioned fluororesin layer.

According to the present invention, since it has a fluororesin layer, it is excellent in heat resistance, and since it is a thick film in which two or more layers are laminated, a sufficient withstand voltage can be ensured and the withstand voltage after bending can be increased. Further, since they are laminated by extrusion, they can slide at the interface between each layer, and flexibility can be realized. Further, since it is an extrusion lamination of two or more layers, the heat capacity of the fluororesin can be reduced at the time of extrusion, and oxidation of the conductor surface and deterioration of plating can be prevented. Further, by laminating the fluororesin layers in multiple layers, even when the winding load is applied and the outer layer is damaged, the outer layer can slide on the boundary surface with the inner layer to disperse the winding load. Wrinkles are less likely to occur and the shape can be stabilized.

In the multilayer insulated wire for a transformer according to the present invention, the two or more fluororesin layers are made of the same material. By doing so, it is possible to realize an efficient terminal peeling operation in which the output of the laser peeling device or the like is constant.

In the multilayer insulated wire for a transformer according to the present invention, the diameter of the conductor is in the range of 0.08 to 0.30 mm, and the thickness of the insulating coating is in the range of 0.05 to 0.10 mm. By doing so, the volume of the transformer ^{can be reduced to 2000 to 13000 mm 3} , and a sufficient withstand voltage can be secured.

In the multilayer insulated wire for a transformer according to the present invention, the insulating coating is composed of two fluororesin layers, the thickness of the first layer is within the range of 0.02 to 0.06 mm, and the thickness of the first layer is within the range of 0.02 to 0.06 mm. The thickness of is in the range of 0.02 to 0.06 mm. Especially, it is preferable that the thickness is the same.

According to the present invention, it is possible to provide a multi-layer insulated wire for a transformer having a high withstand voltage and flexibility, which is used for a transformer or the like in an inverter.

It is explanatory drawing which shows an example of the multilayer insulation electric wire for a transformer which concerns on this invention. It is sectional drawing of the multilayer insulation electric wire for a transformer shown in FIG.

The multilayer insulated wire for a transformer according to the present invention will be described with reference to the drawings. It should be noted that the present invention can be modified in various ways as long as it has its technical features, and is not limited to the forms of the following description and drawings.

[Multilayer insulated wire for transformer]
As shown in FIGS. 1 and 2, the transformer multilayer insulated wire (hereinafter referred to as “multilayer insulated wire”) 10 according to the present invention has a conductor 1 and an insulating coating 2 provided on the outer periphery of the conductor 1. Insulating electric wire 10 used for an inverter transformer, the insulating coating 2 has two or more extruded and laminated fluororesin layers 2A and 2B.

Since the multilayer insulated wire 10 has a fluororesin layer, it has excellent heat resistance, and since it has a thick coating in which two or more layers are laminated, a sufficient withstand voltage can be ensured and the withstand voltage after bending can be increased. Further, since they are laminated by extrusion, they can slide at the interface between each layer, and flexibility can be realized. Further, since it is extruded and laminated with two or more layers, the heat capacity of the resin can be reduced during extrusion, and oxidation of the conductor surface and deterioration of plating can be prevented. Further, by laminating the fluororesin layer in multiple layers, even when the winding load is applied and the outer layer is damaged, the outer layer can slide on the boundary surface with the inner layer to disperse the winding load and wrinkle. Is unlikely to occur, and the shape can be stabilized.

Hereinafter, each configuration will be described.

(conductor)
The conductor 1 is not particularly limited as long as it is applied as the central conductor of the multilayer insulated wire 10 for a transformer, and may be any kind of conductor, regardless of the material or twisted structure. .. For example, it may be composed of one strand extending in the longitudinal direction, may be composed by twisting several strands, or may be configured as a litz wire. The type of the strand is not particularly limited as long as it is a good conductive metal, but it is a good conductive metal conductor such as a copper wire, a copper alloy wire, an aluminum wire, an aluminum alloy wire, or a copper-aluminum composite wire, or a surface thereof. A plating layer is preferably applied to the aluminum. From the viewpoint of coils, copper wire and copper alloy wire are particularly preferable. As the plating layer, a solder plating layer, a tin plating layer, a gold plating layer, a silver plating layer, a nickel plating layer and the like are preferable. Further, the conductor may be covered with an enamel layer or the like for insulation / antioxidant. The cross-sectional shape of the wire is not particularly limited, but the cross-sectional shape may be a circular or substantially circular wire rod, or may be a rectangular shape.

The cross-sectional shape of the conductor 1 is also not particularly limited, but may be circular (including an elliptical shape), rectangular, or the like. The outer diameter of the conductor 1 is also not particularly limited, but for example, the circular wire is preferably about 0.08 to 0.30 mm.

(Insulation film)
As shown in FIGS. 1 and 2, the insulating coating 2 has two or more fluororesin layers 2A and 2B extruded and laminated on the outer periphery of the conductor 1. The fluororesin constituting the fluororesin layer is not particularly limited, and examples thereof include PFA, ETFE, and FEP. Since these fluororesins have excellent heat resistance, it is possible to give the multilayer insulated wire high heat resistance. Further, since the fluororesin has a low dielectric constant, it is also advantageous in increasing the partial discharge start voltage. It is preferable that two or more fluororesin layers are made of the same material. By doing so, it is possible to realize an efficient terminal peeling operation in which the output of the laser peeling device or the like is constant.

The insulating coating 2 is composed of two or more fluororesin layers. By doing so, the insulating coating 2 can be made thicker, a sufficient withstand voltage can be ensured, and the withstand voltage after bending can be increased. The total thickness of the insulating coating 2 is preferably in the range of 0.05 to 0.10 mm, the volume of the transformer after fabrication ^{can be reduced to 2000 to 13000 mm 3} , and a sufficient withstand voltage can be secured. When the insulating coating 2 is composed of two fluororesin layers, the thickness of the first layer is in the range of 0.02 to 0.06 mm, and the thickness of the second layer is 0. It is preferably in the range of 02 to 0.06 mm, and particularly preferably the same thickness. By making the thickness the same, the manufacturing conditions (extrusion conditions, peeling conditions, etc.) can be made the same, and it is easy to manufacture efficiently.

The insulating coating 2 may be formed by two-layer extrusion or three-layer extrusion, but it is formed by two-layer extrusion because the manufacturing cost increases if the number of layers is too large. It is preferable to have. In particular, in the present invention, two fluororesin layers are laminated by extrusion. The extruded layers of the fluororesin layer can slide on the boundary surface of the fluororesin layer without the interlayer close contact as in the baking film, and flexibility can be realized. Then, even when a winding load is applied during transformer manufacturing and the fluororesin layer of the outer layer is damaged, the fluororesin layer of the outer layer slides on the interface with the fluororesin layer of the inner layer to disperse the winding load. In addition to being able to do so, wrinkles are less likely to occur and the shape can be stabilized.

Further, since the number of layers is two or more (preferably two layers), the heat capacity of each layer at the time of extrusion can be reduced even if the fluororesin has a relatively high extrusion temperature, and the conductor surface is oxidized or the plating is deteriorated. Can be prevented. An insulating outer cover (not shown) may be further provided on the outermost circumference of the multilayer insulated wire 10 as needed.

The present invention will be described in more detail with reference to Examples. The present invention is not limited to the following examples, and those skilled in the art can make various changes, modifications and modifications within the scope of the present invention.

[Example 1]
The first layer is a PFA extruded layer (fluororesin layer 2A) with a thickness of 30 μm on the outer circumference of a tin-plated copper wire with a diameter of 0.120 mm provided with tin plating with a thickness of 0.35 μm, and the second layer is also 30 μm thick. A multilayer insulated wire 10 having a total outer diameter of 0.240 mm was produced using the PFA extruded layer (fluororesin layer 2B) of the above. The conductor resistance of the obtained multilayer insulated wire 10 was measured with an ohmmeter and found to be 1.534 Ω / m. The dielectric breakdown voltage was measured with a withstand voltage tester by twisting two strands and was in the range of 12.8 to 14.8 kV.

[Example 2]
Instead of the tin-plated copper wire of the multilayer insulated wire 10 of Example 1, a tin-plated copper wire having a diameter of 0.180 mm provided with tin plating having a thickness of 0.35 μm was used. A multilayer insulated wire 10 having a total outer diameter of 0.300 mm was produced in the same manner as in Example 1 except for the above. The conductor resistance of the obtained multilayer insulated wire 10 was 0.670 Ω / m, and the dielectric breakdown voltage was in the range of 12.2 to 15.0 kV.

[Example 3]
Instead of the tin-plated copper wire of the multilayer insulated wire 10 of Example 1, a tin-plated copper wire having a diameter of 0.260 mm provided with tin plating having a thickness of 0.35 μm was used. A multilayer insulated wire 10 having a total outer diameter of 0.380 mm was produced in the same manner as in Example 1 except for the above. The conductor resistance of the obtained multilayer insulated wire 10 was 0.334 Ω / m, and the dielectric breakdown voltage was in the range of 13.1 to 15.3 kV.

[Comparative Example 1]
In the multilayer insulated wire 10 of Example 1, the first layer was a PFA extruded layer (fluororesin layer 2A) having a thickness of 60 μm, and the second fluororesin layer (fluororesin layer 2B) was not provided. An insulated wire having a total outer diameter of 0.240 mm was produced in the same manner as in Example 1 except for the above. The conductor resistance of the obtained insulated wire was 1.534 Ω / m, and the dielectric breakdown voltage was in the range of 12.5 to 14.5 kV.

[Comparative Example 2]
In the multilayer insulated wire 10 of Example 1, the first layer was a PFA extruded layer (fluororesin layer 2A) having a thickness of 30 μm, and the second fluororesin layer (fluororesin layer 2B) was not provided. An insulated wire having a total outer diameter of 0.180 mm was produced in the same manner as in Example 1 except for the above. The conductor resistance of the obtained insulated wire was 1.534 Ω / m, and the dielectric breakdown voltage was in the range of 6.4 to 7.4 kV.

[Comparative Example 3]
In the multilayer insulated wire 10 of Example 1, a tin-plated copper wire having a diameter of 0.260 mm provided with tin plating having a thickness of 0.35 μm is used, and the first layer is a PFA extruded layer (fluororesin layer 2A) having a thickness of 60 μm. ), And the second fluororesin layer (fluororesin layer 2B) was not provided. An insulated wire having a total outer diameter of 0.380 mm was produced in the same manner as in Example 1 except for the above. The conductor resistance of the obtained insulated wire was 0.334 Ω / m, and the dielectric breakdown voltage was in the range of 12.3 to 15.3 kV.

[Withstanding voltage test when winding load is applied]
A withstand voltage test was performed on the multilayer insulated wire 10 of Example 3 and the insulated wire of Comparative Example 3 when a winding load was applied. The test was conducted in accordance with JIS C3215-0-1 (2014) and JIS C3216-3 (2011) with a mandrel diameter of 0.26 mm (n = 5). As a result, in Example 3, the average was 7.88 kV, and in Comparative Example 3, it was 7.02 kV. As a result, even if the thickness is the same, in Example 3, since the insulating film is formed by the extruded layer composed of two fluororesin layers, it is possible to slide at the boundary surface, and the flexibility is improved. A high withstand voltage could be achieved.

1 Conductor 2 Insulation coating 2A 1st layer 2B 2nd layer 10 Multi-layer insulated wire for transformer

Claims (4)

An insulated wire used for an inverter transformer having a conductor and an insulating coating provided on the outer periphery of the conductor, wherein the insulating coating has two or more extruded and laminated fluororesin layers. Multi-layer insulated wire for transformers. The multilayer insulated wire for a transformer according to claim 1, wherein the two or more fluororesin layers are made of the same material. The multilayer insulation for a transformer according to claim 1 or 2, wherein the diameter of the conductor is in the range of 0.08 to 0.30 mm, and the thickness of the insulating coating is in the range of 0.05 to 0.10 mm. Electrical wire. The insulating coating is composed of two fluororesin layers, the thickness of the first layer is in the range of 0.02 to 0.06 mm, and the thickness of the second layer is 0.02 to 0.06 mm. The multilayer insulated wire for a transformer according to any one of claims 1 to 3, which is within the range of.

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