JPWO2017168749A1 - Insulated wires, coils and motors for vehicles - Google Patents

Abstract

An insulated wire having a high partial discharge start voltage and excellent in flexibility and ATF resistance, a coil made of the insulated wire, and a vehicle motor including the coil are provided. The insulated wire 10 is coated on the outer periphery of the conductor 1, the polyimide layer 2 made of polyimide having an imide group concentration of 36% or less as the innermost insulating film layer coated on the outer periphery of the conductor 1, and the polyimide layer 2. The polyamideimide layer 3 is provided as an outermost insulating film layer, and the polyamideimide layer 3 has a thickness of 20 μm or more and 40 μm or less, and the ratio of the thickness to the total film thickness of the insulating film layer is 50% or less. .

Description

  The present invention relates to an insulated wire, a coil, and a vehicle motor.

  Insulated electric wires used in electric devices such as motors used at high voltages are required to improve partial discharge (corona discharge) starting voltage (see Patent Document 1).

  In recent years, as a vehicle motor, a structure integrated with a transmission and filled with ATF (Automatic Transmission Fluid) is used. In this application, the insulated wire that is a component of the motor is required to have characteristics such as flexibility, and since the insulation layer of the insulated wire directly contacts the ATF, ATF resistance is particularly required (Patent Document) 2). Here, the ATF resistance refers to a characteristic in which even if an insulated wire directly touches the ATF, the electrical insulation performance is not easily lowered.

Japanese Patent No. 5837397 JP-A-2015-133218

  However, it is difficult to obtain an insulated wire having a high partial discharge starting voltage and excellent flexibility and ATF resistance, and an insulated wire satisfying these characteristics is required.

  In addition, since various new ATFs have been developed, even an insulated wire that had resistance to ATF for one specific ATF has ATF resistance to another specific ATF. The problem of not having it has arisen.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an insulated wire having a high partial discharge start voltage and excellent flexibility and ATF resistance, a coil made of the insulated wire, and a vehicle motor equipped with the coil. .

  In order to achieve the above object, the present invention provides the following insulated wire, coil and vehicle motor.

[1] A conductor, a polyimide layer made of polyimide having an imide group concentration of 36% or less as an innermost insulating film layer coated on the outer periphery of the conductor, and an outermost layer coated on the outer periphery of the polyimide layer An insulated wire comprising a polyamideimide layer as an insulating film layer, wherein the polyamideimide layer has a thickness of 20 μm or more and 40 μm or less, and a ratio of the thickness to the total film thickness of the insulating film layer is 50% or less.
[2] The insulated wire according to [1], wherein the insulating film layer has a two-layer structure of the polyimide layer and the polyamideimide layer.
[3] The insulated wire according to [1] or [2], wherein the polyimide layer has a thickness of 30 μm to 85 μm.
[4] The insulated wire according to any one of [1] to [3], wherein the polyamideimide layer is made of polyamideimide having a viscosity of 7000 to 10,000 mPa · s when the nonvolatile content of the paint is 31%.
[5] The insulated wire according to any one of [1] to [4], wherein the polyimide layer is made of polyimide having an imide group concentration of 28 to 34%.
[6] The insulated wire according to any one of [1] to [5], wherein the conductor is a flat wire.
[7] A coil comprising the insulated wire according to any one of [1] to [6].
[8] A vehicle motor including the coil according to [7].

  ADVANTAGE OF THE INVENTION According to this invention, the partial discharge start voltage is high, and the insulated motor wire excellent in the flexibility and ATF resistance, the coil which consists of the said insulated wire, and the motor for vehicles provided with the said coil can be provided.

It is a transverse cross section of an insulated wire concerning an embodiment of the invention.

[Insulated wire]
FIG. 1 is a cross-sectional view of an insulated wire according to an embodiment of the present invention.
The insulated wire 10 according to the embodiment of the present invention includes a conductor 1 and a polyimide layer 2 made of polyimide having an imide group concentration of 36% or less as an innermost insulating film layer coated on the outer periphery of the conductor 1, And a polyamideimide layer 3 as an outermost insulating coating layer coated on the outer periphery of the polyimide layer 2, and the polyamideimide layer 3 has a thickness of 20 μm or more and 40 μm or less, and a thickness with respect to the total thickness of the insulating coating layer. The ratio is 50% or less. Details will be described below.

(Conductor 1)
The conductor 1 can be used without particular limitation as long as it is used for an insulated wire, and examples thereof include a copper wire and a copper alloy wire. These surfaces may be plated with a metal such as nickel. Further, the conductor 1 may be of various shapes such as a round wire, a flat wire, and an irregularly shaped wire, but a flat wire as shown in FIG. 1 is particularly preferable.

(Polyimide layer 2)
The polyimide layer 2 is an innermost insulating coating layer coated on the outer periphery of the conductor 1, that is, an insulating coating layer coated directly on the conductor 1.

  The polyimide layer 2 is a polyimide obtained by imidizing a polyimide precursor obtained by reacting an aromatic diamine component and an aromatic tetracarboxylic dianhydride, and is made of polyimide having an imide group concentration of 36% or less. The imide group concentration of the polyimide is preferably 28 to 34%. In the following description, a to b mean a to b.

  As a specific example of a polyimide having an imide group concentration of 36% or less, it is produced by subjecting a diamine component containing at least one aromatic diamine having three or more benzene rings and an acid composed of tetracarboxylic dianhydride to a dehydration reaction. What imidized the polyimide precursor to perform is mentioned.

  As aromatic diamines having three or more benzene rings, 2,2-bis (4-aminophenoxyphenyl) propane (BAPP), 4,4′-bis (4-aminophenoxy) biphenyl (BAPB), bis [4 -(4-aminophenoxy) phenyl] sulfone (BAPS), 1,3-bis (4-aminophenoxy) benzene (TPE-R), 1,4-bis (4-aminophenoxy) benzene (TPE-Q), Examples include 1,3-bis (3-aminophenoxy) benzene (APB) and 9,9-bis (4-aminophenyl) fluorene (FDA). These may be used alone or in combination of two or more. In addition, you may use together the aromatic diamine which has three or more of the above-mentioned benzene rings, and 4,4'- diamino diphenyl ether (ODA).

  In particular, in the case of a polyimide having an imide group concentration of 28% to 34%, it is preferable to use one or more aromatic diamines having four or more benzene rings such as BAPP, BAPB, and BAPS.

  The polyimide used in this embodiment preferably has a weight average molecular weight Mw of 25000 or more.

  On the other hand, as tetracarboxylic dianhydride, pyromellitic dianhydride (PMDA), 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride (BTDA), 3,3 ′, 4,4 Examples include '-biphenyltetracarboxylic dianhydride (BPDA), 4,4'-oxydiphthalic dianhydride (ODPA), and the like. These may be used alone or in combination of two or more.

  The polyimide layer 2 preferably has a thickness of 30 to 85 μm, more preferably 55 to 85 μm, and still more preferably 60 to 80 μm.

(Polyamideimide layer 3)
The polyamideimide layer 3 is an outermost insulating film layer coated on the outer periphery of the polyimide layer 2.

  The polyamide-imide layer 3 is preferably made of a polyamide-imide having a viscosity of 7000 to 10,000 mPa · s when the non-volatile content of the paint is 31%, and more preferably made of a polyamide-imide having a viscosity of 7000 to 9000 mPa · s.

  The polyamideimide is composed of diisocyanate components such as 4,4′-diphenylmethane diisocyanate (MDI) and tolylene diisocyanate (TDI), trimellitic anhydride (TMA), terephthalic acid (TPA), isophthalic acid (IPA) and the like. It consists of an acid component.

  The polyamideimide layer 3 has a thickness of 20 μm or more and 40 μm or less, and the ratio of the thickness to the total film thickness of the insulating coating layer is 50% or less. The thickness of the polyamideimide layer is preferably 20 to 35 μm, and more preferably 20 to 30 μm. Further, the ratio of the thickness of the polyamideimide layer to the total film thickness of the insulating coating layer is preferably 15% or more and 45% or less, and more preferably 20% or more and 40% or less.

  The polyamideimide used in this embodiment preferably has a weight average molecular weight Mw of 50000 or more.

  The insulated wire 10 may include another insulating layer between the polyimide layer 2 and the polyamideimide layer 3, but an insulating film layer having a two-layer structure of the polyimide layer 2 and the polyamideimide layer 3 is provided. It is preferable that it is an insulated wire (enameled wire) provided

  The polyimide layer 2 can be formed by applying an insulating paint on the conductor 1 and baking it. The polyamideimide layer 3 can be formed by applying an insulating paint on the polyimide layer 2 and baking it. Application and baking are repeated until the desired thickness is achieved.

  The insulating paint contains an organic solvent and the aforementioned polyimide or polyamideimide dissolved in the organic solvent. The insulating coating can be produced, for example, by a known two-step synthesis method, a high-temperature solution polymerization method, or a one-step synthesis method using an isocyanate method.

  The organic solvent is not particularly limited. For example, N-methyl-2-pyrrolidone (NMP), cresol, γ-butyrolactone, N, N-dimethylacetamide (DMAc), N, N-dimethylformamide ( DMF), dimethylimidazolidinone (DMI), cyclohexanone, methylcyclohexanone. These may be used alone or in combination with a plurality of solvents, or may be diluted.

〔coil〕
The coil which concerns on embodiment of this invention consists of the said insulated wire which concerns on embodiment of this invention.

  As a use of the coil according to the embodiment of the present invention, a motor for a vehicle can be cited as a suitable one, but it can also be used for other motors and generators.

[Vehicle motor]
A vehicle motor according to an embodiment of the present invention includes the coil according to the embodiment of the present invention.

  As a vehicle motor, a transmission-integrated vehicle motor having a structure in which a coil and an ATF (Automatic Transmission Fluid) are in direct contact with each other is preferable. In particular, those using ATF containing synthetic lubricating oil can be used as ATF, and even in this case, ATF resistance is exhibited. For example, ATF containing 10 to 20 wt% of synthetic lubricating oil can be mentioned.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited thereto.

  An insulated wire (enameled wire) having the structure of FIG. 1 (provided that Comparative Examples 2 and 4 are polyimide layers only) having an insulating film layer having the structure shown in Table 1 (Examples 1 to 5 and Comparative Examples 1 to 5). Manufactured. A rectangular wire made of pure copper was used as the conductor.

  The polyimide constituting the polyimide layer (lower layer) is a polyimide having an imide group concentration of 32% (containing BAPB and ODA as a diamine component in a ratio (mass ratio) of BAPB: ODA = 20: 80, and PMDA as an acid component. And BPDA in a ratio (mass ratio) of PMDA: BPDA = 70: 30). DMAc was used as the organic solvent for each insulating coating.

  As the polyamideimide constituting the polyamideimide layer (upper layer), a polyamideimide having a non-volatile content of 31% and a viscosity of 8000 mPa · s was used. NMP was used as the organic solvent for each insulating coating.

  Each manufactured insulated wire (enameled wire) was subjected to the following ATF resistance test, measurement of partial discharge starting voltage, and flexibility test. The results are shown in Table 1.

[ATF resistance test]
A 300 mm insulated wire (enameled wire) is immersed in 1300 g of ATF with a water content of 0.5 wt% heated to 150 ° C., and a pressure resistance test (1.5 kV-3 minutes) is performed when 504 hours, 1008 hours, and 1752 hours have elapsed. Samples with a withstand voltage of 1.5 kV or less were rejected. The number of samples is 10 each, and the numbers in Table 1 are the number of failures in 10 samples. The case where the number of failures was 0 at the time of 1752 hours was evaluated as ◎ (passed), the case of 1 to 2 was evaluated as ◯ (passed), and the case of 3 or more was evaluated as × (failed). In addition, what contains 10-20 wt% of synthetic lubricating oil was used as ATF.

[Measurement of partial discharge start voltage]
The sample which made the insulated wire (enameled wire) back to back was produced by the test method based on JISC3003. Next, the terminal film was formed by scraping the insulating film from the end of the sample to a position of 10 mm. Next, an electrode was connected to the terminal processing unit, and a voltage of 50 Hz was applied in an atmosphere having a temperature of 23 ° C. and a humidity of 50%. Thereafter, the voltage was increased at a rate of 10 to 30 V / s, and the voltage value at which 100 pC discharge was generated 50 times per second on the insulated wire was determined. This was repeated three times, and the average value of the three voltage values was taken as the partial discharge start voltage.

  In Examples 1 to 3 and Comparative Examples 1 and 3, when the insulating film layer is only a polyimide layer (100 μm) (Comparative Example 2), evaluation was performed based on the PDIV reduction rate relative to the partial discharge start voltage (PDIV). Then, it evaluated by the PDIV reduction | decrease rate with respect to PDIV when an insulating film layer is only a polyimide layer (60 micrometers) (comparative example 4), and in Example 5, when an insulating film layer is only a polyimide layer (80 micrometers) (comparison) In Example 5, not shown in the table, the PDIV reduction rate relative to PDIV was evaluated. In Comparative Example 5, when the insulating film layer was only a polyimide layer (70 μm) (Comparative Example, not shown in the table) PDIV Was evaluated by the PDIV reduction rate. A case where the PDIV decrease rate was within 5% was evaluated as ◎ (pass), a case where it exceeded 5% and within 7% was evaluated as ◯ (pass), and a case where it exceeded 7% was evaluated as x (fail). In Comparative Examples 2 and 4, since it is an evaluation standard of the PDIV reduction rate, it was set to “−” (not evaluated).

[Flexibility test]
When an insulated wire (enameled wire) elongated in advance at a specific ratio (20% or 30%) was bent 180 degrees, the minimum bending diameter (conductor diameter) at which no crack was generated in the insulating film was obtained. “Crack” was judged visually. The case where the minimum bending diameter (diameter) is 3 mm or less at 20% elongation and 4 mm or less at 30% elongation. The case of ◯ (pass), 20% elongation exceeding 5 mm, and 30% elongation exceeding 8 mm was evaluated as x (failed).

〔Comprehensive evaluation〕
In any of the ATF resistance test, the partial discharge start voltage measurement, and the flexibility test, the evaluation is ◎ or ◯, and the evaluation is ◯ (pass). It was.

  From Table 1, it can be seen that if the polyamideimide layer (upper layer) is 20 μm or more and 40 μm or less, desired performance can be obtained with respect to ATF resistance.

  Further, the lower the ratio of the polyamideimide layer, the lower the PDIV decrease rate (higher PDIV). The polyamideimide layer was 20 μm or more and 40 μm or less, the polyamideimide layer ratio was 50% or less, and the PDIV decrease rate was within 7%. .

  Moreover, when the polyamideimide layer was 20 μm or more and 40 μm or less, the polyamideimide layer ratio was 50% or less, and the flexibility evaluation was acceptable.

  In addition, this invention is not limited to the said embodiment and Example, A various deformation | transformation implementation is possible.

10: insulated wire (enameled wire), 1: conductor, 2: polyimide layer, 3: polyamideimide layer

Claims (8)

Conductors,
A polyimide layer made of polyimide having an imide group concentration of 36% or less as an innermost insulating film layer coated on the outer periphery of the conductor;
The outer periphery of the polyimide layer is coated with a polyamideimide layer as an outermost insulating film layer,
The polyamideimide layer has a thickness of 20 μm or more and 40 μm or less, and the ratio of the thickness to the total thickness of the insulating coating layer is 50% or less.   The insulated wire according to claim 1, wherein the insulating film layer has a two-layer structure of the polyimide layer and the polyamideimide layer.   The insulated wire according to claim 1, wherein the polyimide layer has a thickness of 30 μm to 85 μm.   The insulated wire according to any one of claims 1 to 3, wherein the polyamide-imide layer is made of polyamide-imide having a viscosity of 7000 to 10000 mPa · s when the nonvolatile content of the paint is 31%.   The insulated wire according to any one of claims 1 to 4, wherein the polyimide layer is made of polyimide having an imide group concentration of 28 to 34%.   The insulated wire according to claim 1, wherein the conductor is a flat wire.   The coil which consists of an insulated wire of any one of Claims 1-6. A vehicle motor comprising the coil according to claim 7.

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