Insulated electric wire, production method therefor, coil and coil production method using same

Abstract

This insulated electric wire comprises an insulation coat covering a flat rectangular conductor wire whereof the transversal cross-sectional shape is rectangular. The insulation coat comprises an inner layer covering the surface of the flat rectangular conductor wire, and an outer layer covering the surface of the inner layer. In the rectangular transversal cross section of the flat rectangular conductor wire, among two short sides opposing one another and having an identical length, one of the short sides is covered by the inner layer whereof the thickness (t1) is greater than the thickness (t2) of the inner layer covering the other short side (which includes t2=0). The elastic modulus of the inner layer is smaller than the elastic modulus of the outer layer, or the yield stress of the inner layer is smaller than the yield stress of the outer layer. Alternatively, the elastic modulus and the yield stress of the inner layer are both smaller than the elastic modulus and the yield stressof the outer layer.

Description

technical field [0001] The present invention relates to an insulated wire for coiling which is formed by covering a conductor wire with an insulating film having a two-layer structure, and a method for manufacturing the same. More specifically, it relates to an insulated wire having excellent adhesion between an insulating coating on the inner side of a bend and a conductor wire during bending, and a method for manufacturing the same. Still more in detail, it is related with the manufacturing method of the coil using an insulated electric wire, and a coil. [0002] This application claims priority based on Patent Application No. 2017-055389 for which it applied in Japan on March 22, 2017, and uses the content here. Background technique [0003] In recent years, for hybrid vehicles and electric vehicles, the performance of reactors and motors has been demanded. Along with this, insulated wires for coils used in reactors and motors have changed from coil wires with a circula...

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Problems solved by technology

[0010] However, the resin used in the undercoat layer of the insulated wire disclosed in Patent Document 1 is generally inferior in heat resistance and insulation performance to the resin covered by the outer layer.

In addition, when an insulated wire with a primer layer is used as a coil, there is a problem that when the coating on the outer side of the bend becomes thinner due to edge-to-edge bending, compared with an insulated wire with the same film thickness and no primer layer , there is a tendency for the insulation or heat resistance of the curved outer periphery to deteriorate

In order to solve this problem, it is considered to increase the total thickness of the coating film composed of the primer layer and its outer layer, but there are various problems as follows: if the coating film is thickened, the coating film on the inside of the bend will be damaged when the bending process is performed. Compression causes wrinkles; in order to thicken the coating, multiple dipping coatings must be performed, but the number of times of drying increases and the drying time becomes longer; the adhesion becomes poor due to the formation of an oxide layer at the interface between the conductor and the coating; and due to the coating become thicker, and the manufacturing cost becomes higher, etc.

[0011] In addition, in the winding wire shown in Patent Document 2, the adhesiveness is improved by providing an engaging portion between the inner film and the outer film, but the parts where peeling of the inner film is most likely to occur are the metal as a conductor and the metal as an insulator. However, in this method, it is not possible to sufficiently improve the adhesion to the lead wire of the inner coating in the flat wire subjected to the edge-to-edge bending process.

[0012] Furthermore, in the method for forming a multilayer anionic electrodeposition coating film shown in Patent Document 3, when forming a multilayer coating film by electrodeposition, it is described that excellent adhesion resistance is imparted to the coating film of the first coating layer. method, and described in order to achieve good adhesion, the amount of the curing agent is set to an appropriate amount, but for improving the adhesion of the coating film of the first coating film of the flat conductor wire subjected to edge-to-edge bending processing Inadequate and not suitable for systems that do not inherently use curing agents

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