JP6477346B2 - Coil wire - Google Patents

Description

  The present invention relates to a wire used for a coil. In particular, the present invention relates to a coil wire material that can form a low-loss coil by reducing eddy currents caused by surrounding alternating magnetic fields.

  A coil is used as one part of various electric devices. Examples of the electric device including the coil include a motor, a transformer (transformer), a reactor, and the like. Generally, a coil is formed by winding a winding having a conductor wire in a spiral shape. The winding is typically an enameled wire that has an insulating layer on a conductor wire.

  Patent document 1 is disclosing the insulated wire which uses nickel plating copper wire as a core material, and equips the outer periphery with an adhesion layer and an insulating layer in order.

Japanese Patent Application Laid-Open No. 07-296643

  It is desired that a low-loss coil can be formed in the wire used for the coil.

  For example, in a coil in which the interval between adjacent turns is narrow for the purpose of downsizing and high space factor, the conductor wires forming each turn are arranged close to each other. When an alternating current is passed through such a coil, a magnetic flux from a magnetic field generated by another conductor wire B close to a certain conductor wire A may be linked to the conductor wire A, and an eddy current may be generated in the conductor wire A. In recent years, with the increase in performance and efficiency of various electric devices such as motors, the increase in current has progressed. The alternating magnetic field generated with the increase in current also increases, and the eddy current generated in the conductor wire can also increase.

  As described above, when the eddy current is generated in the conductor wire due to the magnetic flux from the surrounding alternating magnetic field based on the adjacent conductor wire or leakage magnetic flux, and the amount of eddy current increases, the eddy current loss generated in the conductor wire increases, Increases loss. Therefore, it is desirable for the coil wire material to be able to reduce eddy currents due to the surrounding alternating magnetic field.

  In the case where an insulating layer is provided, if there is a surface defect such as a crack in the conductor wire, the insulating layer is not properly formed due to this defect, resulting in a defective portion of insulation and a decrease in yield. Accordingly, a coil wire that can reduce eddy current when using the coil and is excellent in insulation and manufacturability is desired.

  Furthermore, it is desirable to use a coil wire that is easy to bend when being formed into a coil and has excellent coil formability. If the wire is easy to bend and the like, it is easy to reduce deformation due to the springback after the coil is formed, and a coil having excellent dimensional accuracy and shape accuracy can be formed, and the productivity of the coil is also excellent.

  Accordingly, one of the objects of the present invention is to provide a coil wire that can form a low-loss coil by reducing eddy currents caused by surrounding alternating magnetic fields.

  A coil wire according to an aspect of the present invention includes a conductor wire and a magnetic layer formed of a magnetic material on an outer periphery of the conductor wire, and the magnetic layer is a steel-containing layer formed of carbon steel. Is provided.

  The coil wire described above can reduce eddy currents due to the surrounding alternating magnetic field and form a low-loss coil.

It is a schematic sectional drawing which shows an example of the wire material for coils which concerns on Embodiment 1. FIG. It is a schematic sectional drawing which shows an example of the wire material for coils which concerns on Embodiment 2. It is process explanatory drawing explaining an example of the manufacturing method for the wire material for coils (round wire) concerning Embodiment 3. FIG. It is process explanatory drawing explaining an example of the wire for coils (square wire) which concerns on Embodiment 3, and its manufacturing method. FIG. 3 is a schematic configuration diagram showing a measurement circuit used for loss measurement in Test Example 1.

[Description of Embodiment of the Present Invention]
First, embodiments of the present invention will be listed and described.

(1) A coil wire according to an aspect of the present invention includes a conductor wire and a magnetic layer formed of a magnetic material on an outer periphery of the conductor wire, and the magnetic layer is formed of carbon steel. A steel-containing layer is provided.

  The coil wire described above can reduce eddy currents due to the surrounding alternating magnetic field for the following reasons, reduce loss due to eddy currents, and form a low-loss coil.

  When the coil wire is formed, the coil wire material is provided with a magnetic layer made of a magnetic material on the outer periphery of a conductor wire made of a non-magnetic metal although generally excellent in conductivity such as copper. Magnetic flux from the surrounding alternating magnetic field flows through the magnetic layer, and the magnetic flux that can be linked to the conductor wire can be reduced. Since the magnetic layer is substantially made of only a magnetic material and has a sufficient magnetic component, the magnetic flux easily passes through the magnetic layer. Thus, the magnetic layer functions as a magnetic shield that shields the magnetic flux from the surrounding alternating magnetic field to the conductor wire.

In particular, the coil wire described above includes a steel-containing layer made of carbon steel in the magnetic layer. Since carbon steel has a high saturation magnetic flux density, the magnetic flux from the surrounding alternating magnetic field can be sufficiently flowed, the magnetic flux that can be linked to the conductor wire can be effectively reduced, and the eddy current generated in the conductor wire can be reduced. Carbon steel has a higher specific resistance than pure iron and can reduce eddy currents generated in the steel-containing layer itself.
This is because the eddy current that can be generated not only in the conductor wire but also in the magnetic layer can be reduced.

Moreover, said wire for coils is excellent in manufacturability for the following reasons.
When carbon steel is welded, blow holes are not easily formed, and embrittlement such as hydrogen embrittlement hardly occurs. Therefore, when forming a steel content layer using welding so that it may mention later, generation of defects, such as a crack resulting from a blowhole or embrittlement, can be reduced, and a magnetic layer excellent in surface properties can be formed. When an insulating layer is formed on the outer periphery of a magnetic layer having excellent surface properties, the occurrence of defects such as pinholes and blisters can be reduced, the insulating layer can be formed satisfactorily, and a coil wire with excellent insulating properties can be obtained. be able to.
This is because not only the magnetic layer but also the insulating layer can be satisfactorily formed, and the yield reduction can be reduced.

Furthermore, the coil wire described above is excellent in coil manufacturability for the following reasons.
Carbon steel is excellent in plastic workability such as bending, and the above-described coil wire may have a small force required for forming the coil and can be easily wound. Moreover, if the force required for winding is small, the stress remaining in the wire after winding is also small, and it is difficult to produce a springback, and a coil having excellent dimensional accuracy and shape accuracy can be formed.
This is because the coil can be formed satisfactorily in this way, and the yield reduction can be reduced.

(2) As an example of said coil wire, the form whose total content of carbon in the said carbon steel, phosphorus, and sulfur is more than 0 and 0.3 mass% or less is mentioned.

Carbon steel in which the total content of carbon, phosphorus, and sulfur satisfies the above range hardly causes blowholes or embrittlement during welding. Therefore, the above-described embodiment can reduce eddy currents and form a low-loss coil, and can easily form a magnetic layer and a sound insulating layer having excellent surface properties, and is excellent in manufacturability.

(3) As an example of the coil wire, the magnetic layer includes a non-uniform layer having a thick portion and a thin portion having different thicknesses in the circumferential direction in a cross section orthogonal to the axial direction of the conductor wire. And the ratio of the maximum thickness of the thick part to the minimum thickness of the thin part (hereinafter sometimes referred to as the thickness ratio) is 1.1 or more.

  The coil may have a region (hereinafter sometimes referred to as a linkage region) that is more susceptible to magnetic flux from the surrounding alternating magnetic flux than other regions. The said form can arrange | position a thick part in the said linkage area | region among nonuniform layers, and can reduce more reliably the magnetic flux which can be linked to a conductor wire. Even when the magnetic material is a metal, the non-uniform layer has a thin portion. Therefore, the non-uniform layer has a non-uniform thickness as compared with a case where a magnetic layer having a uniform thickness and the same thickness as the thick portion is provided. The eddy current that can be generated in one layer can be reduced. In particular, if the non-uniform layer is made of carbon steel having a relatively high resistance (if the non-uniform layer is a steel-containing layer), it is easier to further reduce eddy currents that can be generated in the non-uniform layer itself. Therefore, the said form can reduce the eddy current resulting from the surrounding alternating magnetic flux about both a conductor wire and a magnetic body layer, and can form a coil with lower loss. In addition, the said form has effects, such as reduction of the constituent material of a magnetic body layer and weight reduction by this reduction.

(4) As an example of the coil wire, the ratio of the cross-sectional area of the magnetic layer to the cross-sectional area of the conductor wire and the magnetic layer (hereinafter sometimes referred to as area ratio) is 3%. The form which is 40% or less is mentioned above.

  The said form is equipped with magnetic path cross-sectional area enough, and can easily flow the magnetic flux from the surrounding alternating magnetic field to a magnetic body layer, and can fully reduce the magnetic flux which can be linked with a conductor wire. And since the magnetic body layer is not too thick, the said form can suppress a diameter increase of a wire, and is easy to perform a bending process. Therefore, the above-mentioned form can reduce eddy current and form a low-loss coil, particularly a small coil, and can easily form a coil, and is excellent in coil manufacturability.

(5) As an example of the coil wire, when the saturation magnetic flux density of the magnetic layer is Bs, the maximum width of the coil wire is w, and the thickness of the magnetic layer is t, Bs × (t / W) A form satisfying ≧ 0.01T is mentioned.

  The larger Bs × (t / w), the higher the magnetic shielding effect and the higher the effect of suppressing loss generated in the conductor wire. In the above embodiment, Bs × (t / w) is 0.01T or more, and a coil with lower loss can be formed.

(6) As an example of said coil wire, the form whose average crystal grain diameter of the metal which comprises the said conductor wire is 200 micrometers or less is mentioned.

  In the above form, the conductor wire is excellent in mechanical properties such as strength (0.2% yield strength, etc.) and toughness (break elongation, etc.), and is excellent in sag resistance and workability such as bending. Therefore, the above-mentioned form can reduce eddy current and form a low-loss coil, and can easily form a coil, and is excellent in coil manufacturability.

(7) As an example of said coil wire rod, the form whose 0.2% yield strength is 60 Mpa or more and whose breaking elongation is 5% or more is mentioned.

  Although the said form is high intensity | strength, it is also high in elongation, and is excellent in sag-resistance and workability, such as a bending process. Therefore, the above-mentioned form can reduce eddy current and form a low-loss coil, and can easily form a coil, and is excellent in coil manufacturability.

(8) As an example of the coil wire, there may be mentioned a form in which an insulating layer is provided on the outer periphery of the conductor wire.

  When an insulating layer is provided on the outer periphery of the magnetic layer, these wires can be insulated by an insulating layer interposed between adjacent coil wires. When an insulating layer is provided between the conductor wire and the magnetic layer, the conductor wire and the magnetic layer can be insulated by the insulating layer interposed between the conductor wire and the magnetic layer. Therefore, the said form can prevent an eddy current produced in the magnetic layer itself from flowing to the adjacent coil wire or the lower conductor wire by the insulating layer, and can form a lower loss coil. In addition, since the surface properties are excellent if the magnetic layer is a steel-containing layer, an insulating layer can be satisfactorily formed on the steel-containing layer, and the above form is also excellent in manufacturability.

[Details of the embodiment of the present invention]
Hereinafter, specific examples of the coil wire according to the embodiment of the present invention will be described with reference to FIGS. In the figure, the same reference numerals indicate the same names. 1 to 4 show cross sections obtained by cutting the coil wire 10 and the like along a plane perpendicular to the axial direction of the conductor wire 11 and the like. 1 to 4 show the magnetic layer 12 and the like exaggerated thickly for easy understanding. The formation regions of the thick portion 12a and the thin portion 12b and the thicknesses of the portions 12a and 12b shown in the lower diagram of FIG. 3 and the lower diagram of FIG. 4 are examples.

(Coil wire)
Outline The coil wire 10 according to the embodiment includes a conductor wire 11 and an outer periphery of the conductor wire 11 so as to cover the conductor wire 11 as shown in the lower diagrams of FIGS. And a magnetic layer 12 made of a magnetic material. Specific examples are shown below. Other specific examples will be described later.
A coil wire 10 according to the first embodiment shown in FIG. 1 is an example including a conductor wire 11 and a magnetic layer 12.
The coil wire 10 according to the second embodiment shown in FIG. 2 is an example including a conductor wire 11, a magnetic layer 12, and an insulating layer 13 formed on the outer periphery of the conductor wire 11.
A coil wire 10 according to Embodiment 3 shown in FIGS. 3 and 4 includes a conductor wire 11 and a magnetic layer 12, and the magnetic layer 12 is arranged around the coil wire 10 in a cross section of the coil wire 10. When viewed in the direction, the thickness of the magnetic layer 12 is different.

  The coil wire 10 according to the embodiment is characterized in that the magnetic layer 12 includes a steel-containing layer containing carbon steel. Hereinafter, each component will be described in detail.

-Conductor wire The conductor wire 11 is a part through which a current mainly flows in the coil wire 10.

.. Composition It is preferable that the constituent material of the conductor wire 11 includes at least one metal selected from metals, particularly copper, copper alloys, aluminum, and aluminum alloys, which are excellent in conductivity. The conductor wire 11 including the metal listed above has a high conductivity and a small electric resistance, so that a predetermined current can flow with a low loss. From the viewpoint of reducing the loss, copper or a copper alloy is preferable, and from the viewpoint of reducing the weight, aluminum or an aluminum alloy is preferable. The metals listed above are generally non-magnetic materials.

Here, “copper” is pure copper containing 99.9% by mass or more of Cu. Specific examples include tough pitch copper, deoxidized copper (eg, phosphorus deoxidized copper), and oxygen-free copper (OFC).
The “copper alloy” herein is a copper-based alloy containing 50% by mass or more, preferably 90% by mass or more of Cu, and containing an additive element other than Cu. Examples of the additive element of the copper alloy include Sn, Zr, Fe, Zn, Ag, Cr, P, Si, Mn, Ti, Mg, and Ni.
Here, “aluminum” is pure aluminum containing 99 mass% or more of Al.
Here, the “aluminum alloy” is an aluminum-based alloy containing 50% by mass or more, preferably 90% by mass or more of Al and containing an additive element other than Al. Examples of the additive element of the aluminum alloy include Si, Cu, Mg, Zn, Fe, Mn, Ni, Ti, Cr, Ca, Zr, and Li.
In addition, inevitable impurities may be included.
From the viewpoint of securing higher conductivity, copper (pure copper) is preferable.

  The content of the additive element may be set as appropriate depending on the type of the additive element as long as desired conductivity is obtained. The total content of additive elements is, for example, 0.1% by mass or more and 30% by mass or less, and further 0.1% by mass or more and 5.0% by mass or less. From the viewpoint of increasing the electrical conductivity, it is preferable that the content of the additive element is small. When the content of the additive element is large, the strength and the like are excellent.

The conductor wire 11 preferably has a low oxygen and hydrogen content. When the magnetic layer 12 is provided immediately above the outer periphery of the conductor wire 11 and the conductor wire 11 and the magnetic layer 12 are in direct contact, if the conductor wire 11 contains a large amount of oxygen or hydrogen, This is because hydrogen may diffuse into the magnetic layer 12 and the ductility and magnetic characteristics of the magnetic layer 12 may be impaired.
The oxygen content of the conductor wire 11 is preferably 50 ppm or less, and more preferably 10 ppm or less, by mass ratio. The hydrogen content of the conductor wire 11 is preferably 10 ppm or less, and more preferably 5 ppm or less, by mass ratio. For the measurement of the oxygen content, for example, infrared spectroscopy can be used. For measurement of the hydrogen content, for example, an inert gas melting method can be used. In addition, an inert gas melting-infrared absorption method and the like can be mentioned.

  In consideration of conductivity, low loss, ductility, maintenance of the characteristics of the magnetic layer 12, and the like, the constituent material of the conductor wire 11 does not contain impurities such as oxygen and hydrogen among pure copper, particularly pure copper, and has the highest purity. Oxygen-free copper is preferred.

.. Structure It is preferable that the metal constituting the conductor wire 11 has a fine crystal structure because of excellent mechanical properties. For example, the average crystal grain size of the metal constituting the conductor wire 11 is 200 μm or less. When the average crystal grain size is 200 μm or less, a conductor wire 11 having a high 0.2% proof stress, breaking elongation and the like can be obtained. The smaller the average grain size is, the better the mechanical properties are, and the upper limit is 100 μm or less, further 80 μm or less, 70 μm or less. The lower limit of the average crystal grain size is not particularly limited. From the viewpoint of production, the average crystal grain size is, for example, 1 μm or more.

  Here, the “average crystal grain size” is an average crystal grain size measured in accordance with the cutting method described in “Method for testing grain size of copper products” defined in JIS H 0501 (1986). The average crystal grain size is measured by taking a cross section of the coil wire 10 and observing the crystal structure of the conductor wire 11 in the cross section with a microscope.

-Shape The shape of the conductor wire 11 is not particularly limited. For example, the conductor wire 11 has various cross-sectional shapes such as a circular shape (FIGS. 1 and 2), an elliptical shape (the lower diagram in FIG. 3), a racetrack shape, a polygonal shape such as a hexagonal shape or a rectangular shape (the lower diagram in FIG. 4). The shape is mentioned. The outer shape of the conductor wire 11 is typically a shape similar to the outer shape of the coil wire 10, although it depends on manufacturing conditions.

-Size The cross-sectional area of the conductor wire 11 can be appropriately selected according to the current value, for example. For example, in applications where a large current of 2 A or more flows, the cross-sectional area is 0.4 mm ² or more, further 0.5 mm ² or more, 0.8 mm ² or more. For low current applications, the cross-sectional area is less than 0.4 mm ² , and further 0.3 mm ² or less. The upper limit of the cross-sectional area is not particularly limited, but if it is 50 mm ² or less, it is easy to bend and excellent in workability, and a coil having a high space factor can be formed because it is relatively thin.
When the conductor wire 11 is a round wire, the diameter φ of the conductor wire 11 is about 0.5 mm or more and 8 mm or less.
When the conductor wire 11 is a rectangular wire such as a flat wire or an elliptical wire, the length of the long side of the conductor wire 11 is about 0.5 mm to 10 mm and the length of the short side is about 0.2 mm to 5 mm. It is done.

.. Electrical conductivity The higher the electrical conductivity of the conductor wire 11, the lower the loss and the better the current can flow. Specific conductivity includes 70% IACS or more, 80% IACS or more, 90% IACS or more.

Magnetic Layer The magnetic layer 12 is formed of a magnetic material, and mainly functions as a magnetic shield that prevents and reduces the magnetic flux from the surrounding alternating magnetic field from passing through the conductor wire 11. When a surrounding alternating magnetic field is applied to the coil wire 10, the magnetic flux from the alternating magnetic field flows to the magnetic layer 12, whereby the magnetic flux interlinking with the conductor wire 11 can be reduced.

.. Composition The constituent material of the magnetic layer 12 is a magnetic material, particularly a soft magnetic material. Ferromagnetic materials that can be expected to have a high magnetic shielding effect are preferable, and iron-based materials with high relative permeability and high saturation magnetic flux density are more preferable. Moreover, if it is an iron-type material with a high specific resistance, the eddy current which arises in magnetic body layer 12 itself can be reduced. Therefore, in the coil wire 10 according to the embodiment, the magnetic layer 12 includes a steel-containing layer formed of carbon steel, which is an iron-based material having a high saturation magnetic flux density and a relatively high specific resistance.

“Carbon steel” as used herein contains carbon (C) in a range of more than 0 to about 2% by mass, and in addition, silicon (Si), manganese (Mn), phosphorus (P), sulfur (S), etc. Is an iron-based alloy containing a small amount of. For example, low carbon steel (typically C: 0.15 mass% or less) or medium carbon steel (typically C :) specified in JIS G 3141 (2011), JIS G 3118 (2010), etc. 0.30 mass% or less, Si: 0.15 mass% to 0.4 mass%) and the like. Examples of the content (% by mass) of Mn, P, and S include the following.
Mn amount: 1.20% or less, P amount: 0.100% or less, S amount: 0.040% or less

  In particular, if the total content of carbon, phosphorus, and sulfur in carbon steel is low, embrittlement such as blowholes or hydrogen embrittlement is unlikely to occur when welding is performed to form a steel-containing layer. It is easy to form an excellent steel-containing layer, and the productivity of the coil wire 10 is excellent. Moreover, when forming the insulating layer 13 in the outer periphery of a steel containing layer, the insulating layer 13 can be formed favorably and it is excellent also in the manufacturability of the coil wire rod 10 provided with the insulating layer 13. As the total content is smaller, blowholes and embrittlement are less likely to occur, and it is preferably 0.6% by mass or less, and more preferably 0.5% by mass or less. Considering the formation of a good insulating layer 13, the total content is preferably more than 0 and not more than 0.3% by mass, more preferably not more than 0.2% by mass, and further preferably not more than 0.15% by mass. For example, refining or the like is performed so that the total content satisfies a desired range to adjust the components of the carbon steel material used for forming the steel-containing layer, in particular, to reduce phosphorus and sulfur.

..Structure The coil wire 10 includes only one magnetic layer 12, and the insulating layer 13 (intermediate insulating layer) is provided in addition to the single-layer structure (FIGS. 1 to 4) in which this layer is a steel-containing layer. A plurality of magnetic layers 12 are provided, and each of the plurality of magnetic layers 12 is a steel-containing layer (not shown), and as the plurality of magnetic layers 12, at least one steel-containing layer and the remainder are The form (not shown) provided with the layer comprised from magnetic materials other than carbon steel is mentioned. The magnetic material other than carbon steel is preferably an iron-based material as described above. For example, if it is a high μ layer made of an iron-based material having a high magnetic permeability, magnetic flux from the surrounding alternating magnetic field easily passes, and if it is a high Bs layer made of an iron-based material having a high saturation magnetic flux density, the surrounding alternating If it is a high electrical resistance layer made of an iron-based material that can sufficiently pass magnetic flux from a magnetic field, eddy currents generated in this layer itself can be reduced.

  The magnetic layer 12 having a multilayer structure in which two or more layers made of different magnetic materials are stacked can be provided without using the insulating layer 13. Of the multiple layers, at least one layer may include a steel-containing layer. For example, as the magnetic layer 12 having a multilayer structure, a form in which the inner region of the magnetic layer 12 is a steel-containing layer and the region on the surface side is an iron oxide layer.

.. Other Magnetic Materials The “iron-based material” here is a metal containing Fe, a compound containing Fe, or the like. Specific examples include at least one soft magnetic material selected from iron, iron-based alloys excluding carbon steel, and iron-based compounds.
Here, “iron” is pure iron containing 99.8% by mass or more of Fe.
Examples of iron-based alloys include permalloy (Fe-Ni alloy), permendur (Fe-Co alloy), silicon steel (Fe-Si alloy), iron-based amorphous alloy, Sendust (Fe-Si-Al alloy), and the like. Can be mentioned. Permendur, permalloy, silicon steel, iron-based amorphous alloy, and the like are iron-based materials having a large specific resistance (for example, 20 μΩ · cm or more).
Examples of the iron compound include iron oxide (iron oxide) such as ferrite (Fe ₂ O ₃ ), FeO, and Fe ₃ O ₄ .
Examples of magnetic materials other than iron-based materials include soft magnetic materials such as cobalt-based materials containing Co (pure metals, alloys, etc.) and nickel-containing materials containing Ni (pure metals, alloys, etc.).

  It is preferable that the oxygen content and the hydrogen content of the iron-based material (iron-based alloy including carbon steel, iron, iron-based compound, etc.) constituting the magnetic layer 12 are also small. If the magnetic layer 12 is formed of an iron-based material having an excessive oxygen or hydrogen content, the ductility and magnetic properties of the magnetic layer 12 are impaired as described above, and the magnetic body 12 will be described later. This is because, when the layer 12 is formed, when welding is performed using a tape made of an iron-based material, blow holes or other welding defects may occur. The oxygen content of the iron-based material constituting the magnetic layer 12 is preferably, for example, 50 ppm or less and 10 ppm or less by mass ratio. The hydrogen content of the iron-based material constituting the magnetic layer 12 is preferably, for example, 10 ppm or less and 5 ppm or less by mass ratio. As a method for measuring the oxygen content and the hydrogen content, the method described for the conductor wire 11 can be used.

.. Magnetic characteristics The higher the saturation magnetic flux density of the magnetic layer 12, the more easily the magnetic saturation of the magnetic layer 12 is suppressed, and more magnetic flux from the surrounding alternating magnetic field can flow through the magnetic layer 12. The magnetic flux that can be linked to each other can be further reduced, which is preferable. Specific examples of the saturation magnetic flux density include 0.5T or more, and more preferably 1.0T or more, 1.5T or more, 1.8T or more, and 2.0T or more. When a plurality of magnetic layers 12 (including a multilayer structure) are provided, it is preferable that the saturation magnetic flux density of any layer is high. The saturation magnetic flux density of the steel-containing layer is, for example, 1.5T or more.

.. Electrical characteristics It is preferable that the electrical resistance of the magnetic layer 12 is larger because eddy currents are less likely to occur in the magnetic layer 12 itself, and eddy current loss can be reduced. Specific resistance of the steel-containing layer is 10 μΩ · cm or more, and further 12 μΩ · cm or more. The specific resistance of the magnetic layer made of an iron-based material other than carbon steel is, for example, 20 μΩ · cm or more. When a plurality of magnetic layers 12 (including a multilayer structure) are provided, it is preferable that all layers have high specific resistance.

.. Area ratio The larger the area ratio of the magnetic layer 12 in the cross section of the coil wire 10, the more sufficient the magnetic path cross-sectional area can be secured and the magnetic saturation of the magnetic layer 12 can be suppressed. As a result, a magnetic flux from the surrounding alternating magnetic field can be sufficiently passed through the magnetic layer 12, and a high magnetic shielding effect can be expected.
If the area ratio is small to some extent, an eddy current that can be generated in the magnetic layer 12 itself can be reduced, and further, suppression of an increase in diameter and good workability can be expected.
Considering the magnetic shield effect and the suppression of increase in eddy current loss in the magnetic layer 12 itself, the ratio (area ratio) of the sectional area of the magnetic layer 12 to the combined sectional area of the conductor wire 11 and the magnetic layer 12 Is preferably 3% or more and 40% or less. The area ratio is preferably 5% to 30%, more preferably 10% to 25%. When a plurality of magnetic layers 12 (including a multilayer structure) are provided, the “cross-sectional area of the magnetic layer 12” is the sum of the cross-sectional areas of the plurality of magnetic layers 12.

.. Non-uniform layer The coil wire 10 according to the third embodiment shown in FIGS. 3 and 4 is a thick portion having a thickness different from the circumferential surface of the conductor wire 11 in the cross section of the coil wire 10 as the magnetic layer 12. A non-uniform layer having 12a and a thin portion 12b is provided. It can be said that the coil formed of the coil wire rod 10 having the non-uniform layer includes a portion where the thick portion 12a exists and a portion where the thin portion 12b exists. If the coil is formed so that the portion where the thick portion 12a exists is disposed in the interlinkage region where the magnetic flux from the surrounding alternating magnetic field is more easily received than the other regions in the coil, the magnetic shielding effect by this non-uniform layer Can be obtained satisfactorily. In addition, the thin portion 12b can reduce the constituent material of the magnetic layer 12, reduce the diameter of the coil wire 10, reduce the weight, and suppress the increase in rigidity due to the provision of the magnetic layer 12. And can be easily bent. Therefore, the coil wire 10 according to the third embodiment is easy to form a coil, is excellent in the manufacturability of the coil, and can reduce the spring back and is excellent in the shape retention of the coil.

Examples of the interlinking region include the following.
(A) In one wire forming one coil, a region on the side where the wires forming the turn are adjacent to each other (b) When a plurality of coils are arranged close to each other, a region on the adjacent side in each coil (c ) When there are members that can be arranged close to the coil to generate magnetic flux (including leakage magnetic flux), such as a magnetic core where the coil is placed, a magnet that is close to the coil, etc., the side of the coil that is close to these members Area

  Since the magnetic shielding effect is enhanced as the thick portion 12a is thicker, it is preferable that the ratio (thickness ratio) of the maximum thickness of the thick portion 12a to the minimum thickness of the thin portion 12b is 1.1 or more. If the thickness ratio is 1.2 or more, further 1.4 or more, 1.5 or more, the magnetic flux from the surrounding alternating magnetic field can be sufficiently passed through the thick portion 12a, and the magnetic shielding effect can be further enhanced. If the thick portion 12a is too thick, an increase in eddy current generated in the thick portion 12a and a decrease in workability of the coil wire 10 are likely to occur, so the upper limit of the thickness ratio is about 10 or less, and further 5 or less. Degree.

The distinction between the thick part 12a and the thin part 12b in one magnetic layer 12 is performed based on the average thickness ta of the magnetic layer 12. The average thickness ta is obtained as follows.
In the cross section of the coil wire 10, at least 10 points of thickness are measured at equal intervals in the circumferential direction of one magnetic layer 12 to be measured, and the average of the thicknesses of 10 points or more is determined as the magnetic layer. The average thickness ta is 12. The measurement points include the maximum thickness tx and the minimum thickness tn of the magnetic layer 12 to be measured.
A portion having a thickness greater than the average thickness ta is a thick portion 12a, a portion having an average thickness ta or less is a thin portion 12b, and the magnetic layer 12 having both portions 12a and 12b is a non-uniform layer. The thick part 12a includes the thickest part having the maximum thickness tx. The thin portion 12b includes the thinnest portion having the minimum thickness tn.

In the cross section of the coil wire 10, the position of the thick portion 12 a with respect to the conductor wire 11 and the length ratio of the thick portion 12 a to the circumferential length of the conductor wire 11 are the thick portions in the interlinkage region of the coil described above. It may be selected in consideration of the interlinking region and the shape of the conductor wire 11 so that 12a is arranged.
As the length ratio of the thick part 12a is larger, the thick part 12a can be surely arranged in the interlinkage region, and the magnetic shield effect can be obtained better. In the case where the interlinkage region is small and the length ratio of the thick portion 12a may be small, if the magnetic layer 12 is provided with a non-uniform layer in which only a very small portion is thick and most of the thickness is uniform. In addition to reducing eddy currents that can occur in the coil itself, the coil wire 10 can be easily bent.

  In the cross section of the coil wire 10, the magnetic layer 12 is present over the entire circumference of the conductor wire 11, that is, when the magnetic layer 12 is provided with an annular or frame-like magnetic layer 12, If it is a uniform layer, a part in the circumferential direction is the thick part 12a, and the remaining part is the thin part 12b.

  Alternatively, in the cross-section of the coil wire 10, the magnetic body layer 12 is not present in a part of the conductor wire 11 in the circumferential direction, and an exposed region in which the outer peripheral surface of the conductor wire 11 is exposed is provided. it can. For example, the form provided with the C-shaped magnetic body layer 12 with respect to the conductor wire 11 shown in FIG. 3 is mentioned. The form including the exposed region can reduce the eddy current that can be generated in the magnetic layer 12 itself, and can be a coil wire 10 with lower loss. Further, this form is expected to be easy to bend by reducing the improvement in rigidity due to the magnetic layer 12. The thickness of the magnetic layer 12 can be uniform throughout the entire region, or different in thickness from the circumferential direction of the conductor wire 11. It can be said that the latter form is a form provided with the nonuniform layer which has an exposed area | region and the thick part 12a and the thin part 12b. The steel-containing layer can be such a non-uniform layer.

.. Thickness The average thickness ta of one magnetic layer 12 is, for example, more than 10 μm and not more than 300 μm, and more preferably not less than 30 μm and not more than 200 μm. The maximum thickness tx of one magnetic layer 12 is, for example, more than 10 μm and not more than 300 μm, further not less than 30 μm and not more than 250 μm, and further not more than 200 μm. The minimum thickness tn is, for example, about 2/3 or less of the maximum thickness tx, Or more than 0 micrometer and 270 micrometers or less, Furthermore, 27 micrometers or more and 180 micrometers or less are mentioned.
When the thickness of the magnetic layer 12 is uniform in the circumferential direction of the conductor wire 11 (FIGS. 1 and 2), the maximum thickness tx, the minimum thickness tn, and the average thickness ta of the magnetic layer 12 are as follows. Substantially equal.

-Other characteristics, configuration, etc.-(Bs x (t / w))
In the coil wire 10, Bs × (t / w) ≧ 0..., Where Bs is the saturation magnetic flux density of the magnetic layer 12, w is the maximum width of the coil wire 10, and t is the thickness of the magnetic layer 12. It is preferable to satisfy 01T. When the maximum width w of the coil wire 10 is large, the maximum width of the conductor wire 11 also tends to be large, and the region where the magnetic flux from the surrounding alternating magnetic field in the conductor wire 11 can be linked easily increases. If the saturation magnetic flux density Bs of the magnetic layer 12 is large to some extent, magnetic saturation is difficult, and even if the magnetic layer 12 can be sufficiently supplied with magnetic flux from the surrounding alternating magnetic field and the thickness t of the magnetic layer 12 is small to a certain degree, it is thin. The magnetic flux that can be linked to the conductor wire 11 can be reduced. When the magnetic layer 12 is thin, the coil wire 10 can be reduced in diameter and thickness. Alternatively, if the thickness t of the magnetic layer 12 is large to some extent, even if the saturation magnetic flux density Bs is small to some extent, the magnetic flux can be sufficiently passed through the magnetic layer 12 and the magnetic flux that can be linked to the conductor wire 11 can be reduced. In this case, for example, the degree of freedom in selecting the magnetic material constituting the magnetic layer 12 can be increased.

If both the saturation magnetic flux density Bs and the thickness t are large, the magnetic flux that can be linked to the conductor wire 11 can be further reduced, and the coil wire 10 with lower loss can be obtained. That is, as the value of Bs × (t / w) is larger, the loss reduction effect of the conductor wire 11 tends to be enhanced. Therefore, Bs × (t / w) is more preferably 0.02T or more, further 0.05T or more, and 0.1T or more.
The “maximum width of the coil wire” is, for example, a diameter when the cross-sectional shape of the coil wire 10 is a circle (round wire), a long diameter when it is an ellipse, and a long side length when it is a rectangle (such as a flat wire). It is.
“The thickness of the magnetic layer” is the average thickness ta of the magnetic layer 12 measured in the cross section of the coil wire 10.
When a plurality of magnetic layers 12 (including a multilayer structure) are provided, “t” of Bs × (t / w) is the total thickness of the average thickness ta of each layer. The saturation magnetic flux density “Bs” of Bs × (t / w) is the value of the layer that takes the minimum value among the saturation magnetic flux density of each layer.

.. Mechanical properties It is desired that the coil wire 10 is difficult to crack, break or excessively deform when forming a coil, and does not easily sag when using a coil. As such a coil wire 10, one having a 0.2% proof stress of 60 MPa or more and a breaking elongation of 5% or more is preferable. The higher the 0.2% proof stress and the elongation at break, the better the mechanical properties, the easier it is to perform bending during coil manufacture, and the more difficult it is to sag when using the coil. Therefore, the 0.2% proof stress is 70 MPa or more, more preferably 80 MPa or more, and the elongation at break is 10% or more, more preferably 15% or more.

-Shape The shape of the coil wire 10 is not particularly limited. For example, the coil wire 10 has various cross-sectional shapes such as a circular shape (FIGS. 1 to 3), an elliptical shape, a race track shape, a polygonal shape (FIG. 4) such as a hexagonal shape or a rectangular shape (FIG. 4). Can do. The outer shape of the coil wire 10 may be similar to the outer shape of the conductor wire 11 (FIGS. 1 and 2) or may be different from the outer shape of the conductor wire 11 (FIGS. 3 and 4).

.. Insulating layer The coil wire 10 can include an insulating layer 13 on the outer periphery of the conductor wire 11. Form α (hereinafter, this insulating layer may be referred to as an outer insulating layer, not shown) including the insulating layer 13 on the outer periphery (radially outer side) of the magnetic layer 12, the conductor wire 11, the magnetic layer 12, and Form β (hereinafter, this insulating layer may be referred to as an intervening insulating layer, FIG. 2), Form γ (not shown) including both the outer insulating layer and the intervening insulating layer, as described above In the case where a plurality of magnetic layers 12 are provided, a form δ including an intermediate insulating layer between the magnetic layers 12 is exemplified. Typically, in the forms α and γ, the outer insulating layer forms the outer layer, and in the form β, the magnetic layer 12 forms the outermost layer of the coil wire 10.

The coil formed of the coil wire rod 10 having the outer insulating layer can achieve insulation between turns and insulation between the coil and its surrounding members by the outer insulating layer. The outer insulating layer can also cover the above-described exposed region.
The coil formed of the coil wire material 10 including the intervening insulating layer and the intermediate insulating layer can achieve insulation between the conductor wire 11 and the magnetic layer 12 and insulation between the magnetic layers 12 by these insulating layers. it can. Therefore, even if an eddy current is generated in the magnetic layer 12 itself, the eddy current can be prevented from flowing into the conductor wire 11 or another magnetic layer 12 below, and a low-loss coil can be obtained.

The constituent material of the insulating layer 13 is an insulating resin. Specifically, polyimide resin, polyamideimide resin, polyesterimide resin, polyurethane resin, polyester resin, polyolefin resin, polyamide resin, polyethersulfone resin, polyphenylene sulfide resin, polyetheretherketone resin, polytetrafluoroethylene resin, etc. But not necessarily.
The insulating layer 13 can have a single layer structure or a multilayer structure of two or more layers. In the case of a multilayer structure, the material of each layer can be made different.
The thickness of the insulating layer 13 can be appropriately selected according to the magnitude of the current flowing through the conductor wire 11. For example, the thickness of the insulating layer 13 is 5 μm or more and 500 μm or less, and further 5 μm or more and 100 μm or less. Particularly, the lower limit is 30 μm or more and 50 μm or more.

.. Other constituent layers The coil wire 10 is provided with a lubricating layer (not shown) in the outermost layer, or the conductor wire 11 or the magnetic layer 12 and the insulating layer 13 (intervening insulating layer, outer insulating layer, intermediate insulating layer) An adhesion layer (not shown) may be provided between the two layers. Lubricity can be improved by providing a lubricating layer containing additives such as a lubricity improver. Adhesion with the insulating layer 13 can be improved by providing an adhesion layer containing an additive such as an adhesion improver.
Alternatively, of the insulating layer 13, an outer insulating layer that forms the outermost layer of the coil wire 10 is formed by blending an additive such as a lubricity improver, or an adhesion improver or the like is added to the insulating layer 13. It is possible to mix an agent.

Examples of the lubricity improver include paraffins such as liquid paraffin and solid paraffin, various waxes, and lubricants such as polyethylene resin, fluororesin, and silicone resin.
Examples of the constituent material of the lubricating layer include those obtained by binding the lubricant with a binder resin. Examples of the binder resin include the insulating resin described in the section of the insulating layer 13. The constituent material of the lubricating layer is preferably an amide-imide resin to which lubricity is imparted by adding paraffin or wax.
Adhesion improvers include, for example, acetylenes (such as 1-hexyne), alkynols (such as propargyl alcohol and 1-hexyn-3-ol), aldehydes (such as benzaldehyde and cinnamic aldehyde), and amines (laurylamine, N , N′-dimethylcetylamine, trimethylcetylammonium promide, etc.), mercaptans (eg cetyl mercaptan, 2-mercaptoimidazole, 5-amino-1,3,4-thiadiazole-2-thiol), thioureas (thio) Urea, phenylthiourea, etc.) and melamine.
Among these mercaptans, 2-mercaptoimidazole has a great effect of improving adhesion.

(Effect of coil wire)
Since the coil wire 10 according to the embodiment includes the magnetic layer 12 on the outer periphery of the conductor wire 11, the magnetic flux from the surrounding alternating magnetic field flows through the magnetic layer 12 and the magnetic flux to be linked to the conductor wire 11 is generated. Can be reduced. In particular, in the coil wire 10, since the magnetic layer 12 includes a steel-containing layer formed of carbon steel, the magnetic shield effect can be satisfactorily exhibited, and an eddy current that can be generated in the steel-containing layer itself is generated. Less. Therefore, the coil wire 10 can form a low-loss coil by reducing the eddy current that can be generated in the conductor wire 11 and the magnetic layer 12 itself by the surrounding alternating magnetic field. Such a coil wire 10 can be suitably used for a coil provided in various electric devices such as a motor.

  Moreover, the wire 10 for coils of embodiment is equipped with the steel containing layer which can reduce generation | occurrence | production of the defect resulting from welding and is excellent in surface property, when using welding for formation of a steel containing layer. In the case of the coil wire rod 10 provided with the insulating layer 13, since the insulating layer 13 can be satisfactorily formed on the outer periphery of the steel-containing layer having excellent surface properties, the occurrence of defects such as pinholes and blisters can be reduced, and the insulating property It can be set as the coil wire 10 which is excellent. Since the reduction in yield can be reduced by reducing the defects, the coil wire 10 according to the embodiment is excellent in manufacturability.

  Furthermore, although the coil wire 10 according to the embodiment includes a steel-containing layer, it is easy to bend, and therefore, a force required for winding may be small, and a springback hardly occurs after coil forming. Therefore, the coil wire rod 10 of the embodiment can form a coil having excellent dimensional accuracy and shape accuracy, and is excellent in coil manufacturability. In addition, since carbon steel is less expensive than pure iron or a highly functional magnetic material, the coil wire 10 according to the embodiment is excellent in economic efficiency by including a steel-containing layer in the magnetic layer 12.

(Manufacturing method of coil wire)
As a manufacturing method of the coil wire rod 10, for example, the following fitting method can be used.
-Fitting method Here, the fitting method refers to a state in which a material wire that will eventually become the conductor wire 11 is prepared, and a member made of a magnetic material (hereinafter also referred to as a magnetic member) is fitted to the material wire. It is a method of performing plastic working such as wire drawing and rolling. The magnetic member finally becomes the magnetic layer 12.

(Preparation process) The process which arrange | positions a magnetic member around a raw material wire, and produces the preparatory material which covered the outer periphery of the raw material wire with the magnetic member.
(Fitting process) A process of producing a composite material in which the preparation material is subjected to plastic working and tightened, and a magnetic member is fitted to the outer periphery of the material wire.
(Processing step) A step of forming a magnetic layer on the outer periphery of the conductor wire by subjecting the composite material to plastic working until the composite material has a predetermined wire diameter.

-Preparation process In order to arrange a magnetic member on the outer periphery of a raw material wire in a preparation process, the following is mentioned, for example.
(S) A tape, a sheet, or a wire made of a magnetic material is wound around the material wire.
(P) A material wire is inserted into a pipe made of a magnetic material.
(W) A wire composed of a magnetic material is vertically attached around the material wire along the axial direction.
After the above-described magnetic member is disposed on the outer periphery of the material wire, the following fitting process is easily performed by joining the end surfaces of the magnetic members or the material wire and the magnetic member by welding or brazing as necessary. In particular, when a steel-containing layer is formed, a method of winding (s) a tape or the like and fixing it by welding can be suitably used.

  For example, the thickness and thickness ratio of the magnetic layer and the area ratio of the magnetic layer in the coil wire can be adjusted by adjusting the thickness of the magnetic member described above, Rate) or by adjusting the cross-sectional shape. The size (thickness) of the magnetic member to be prepared in consideration of the cross-sectional shape of the conductor wire, the degree of processing, the processing state, etc. so as to obtain a magnetic layer satisfying the desired thickness, thickness ratio, area ratio, etc. Etc.).

The material wire can be typically manufactured by a process of casting ⇒ hot working (rolling, forging, extrusion) ⇒ cold working (rolling, wire drawing), and appropriate heat treatment.
Magnetic members such as tapes, sheets, wires, and pipes can be manufactured by known methods.

.. Fitting process In the fitting process, the magnetic member is tightened from outside in the radial direction, and the material wire and the magnetic member are fitted and integrated. Examples of the plastic processing for tightening include wire drawing and rolling.

.. Machining process In the machining process, plastic working such as wire drawing and rolling is performed so that the material wire and magnetic member have a predetermined size (cross-sectional area, thickness, etc.) and shape. Pipes with different wall thicknesses in the circumferential direction can also be used.

  When manufacturing a wire for a coil (see FIGS. 3 and 4) including a non-uniform layer including a thick part and a thin part, the magnetic member satisfies a specific thickness ratio and is a conductor wire in the processing step. The processing state may be adjusted so that a magnetic layer (non-uniform layer) having a specific thickness in a specific region (region corresponding to the interlinkage region of the coil) is obtained.

  For example, by changing the shape of the wire drawing die, adjusting the rolling conditions (number of rolling operations, rolling reduction of each pass, groove shape of the rolling roll used for each pass, etc.), adjusting the cross-sectional shape, etc. Can be mentioned. Specifically, as shown in the upper diagram of FIG. 3, a composite material 30 including an annular magnetic member 22 is prepared on the outer periphery of a round wire 21, and a wire drawing die or a hole die having an appropriate shape is prepared. In this way, a workpiece 40 having an elliptical outer shape is formed (middle of FIG. 3), and the workpiece 40 is drawn with a circular wire drawing die to form a coil wire 10 having a circular outer shape. Can be mentioned. As shown in the lower diagram of FIG. 3, the coil wire 10 of the round wire has an elliptical conductor wire 11, a thin portion 12 b in a region near the end of the long diameter of the conductor wire 11, The magnetic layer 12 having the thick portion 12a is provided in the region. Thus, when forming the coil wire 10 of the round wire provided with a non-uniform | heterogenous layer, it makes it oval shape etc. in an intermediate process stage, and shape | molds in a circular shape by final process.

  Alternatively, as shown in the upper diagram of FIG. 4, a composite material 30 including a rectangular frame-shaped magnetic member 22 is prepared on the outer periphery of a rectangular material wire 21, and rolling is performed so as to press an intermediate portion between two opposing surfaces. Then, a deformed workpiece 40 in which the middle part of each surface is recessed is formed (middle figure in FIG. 4), and the workpiece 40 is subjected to square wire rolling to form a coil wire 10 having a rectangular outer shape. To do. As shown in the lower diagram of FIG. 4, the rectangular coil wire 10 has a polygonal conductor wire 11, a thin wire portion 12 b in a region near the middle portion in the vertical direction of the conductor wire 11, and the other The magnetic layer 12 having the thick portion 12a is provided in the region. When the coil wire 10 is a square wire, the coil wire 10 having a non-uniform layer may be manufactured by processing according to the ratio of the short side to the long side (aspect ratio) of the conductor wire 11. is there.

In the processing step, the processing can be repeated until the final wire diameter or final shape is reached. In this case, if necessary, an intermediate heat treatment step for performing a heat treatment between the processing can be provided. The object to be processed is softened by the heat treatment, and the next processing can be easily performed.
A final heat treatment step for performing a heat treatment after the processing step can be provided. In the final heat treatment step, the heat treatment temperature is, for example, 150 ° C. or more and 900 ° C. or less, and the heat treatment time is, for example, from the viewpoint of suppressing the coarsening of the crystal grain size of the conductor wire while improving coil formability by softening. It may be set to 1 second or more and 10 hours or less. When the conductor wire is a copper wire, the average crystal grain size can be easily set to 200 μm or less when the temperature of the final heat treatment is 500 ° C. or less. The heat treatment conditions may be selected from the above range in consideration of the composition of the conductor wire and the degree of processing.

Other methods Instead of using the magnetic member described above, a plating layer made of a magnetic material formed on the outer periphery of the material wire by various plating methods can be used. The processing steps are the same as those described above.
A plating method can be used for manufacturing a wire for a coil including a non-uniform layer including a thick portion and a thin portion. In this case, a conductor wire having a predetermined wire diameter and shape is prepared, masking is performed on a predetermined region of the conductor wire and plating is performed. You can adjust the height.

-Insulation process When manufacturing the coil wire 10 provided with the insulating layer 13 on the outer periphery of the conductor wire 11, the insulating layer is formed on the outer periphery of the material wire, the outer periphery of the conductor wire 11, the outer periphery of the magnetic layer 12, etc. A process can be provided. For example, the insulating layer may be formed by applying the insulating resin described in the section of the insulating layer 13 and then baking it.

[Example 1]
A coil wire comprising a magnetic layer composed of a magnetic material on the outer periphery of a conductor wire, and further comprising an insulating layer (outer insulating layer) on the outer periphery of the magnetic layer, wherein the material of the magnetic layer is different. The loss during energization was investigated.

  In this test, a copper wire made of oxygen-free copper and a magnetic member made of various iron-based materials (carbon steel, pure iron, permalloy, permendur) shown in Table 1 were prepared and fitted. A coil wire is produced by a legal method. All of the prepared iron-based materials (the following tapes) have an oxygen content of 10 ppm or less and a hydrogen content of 5 ppm or less. For the measurement of each content, an inert gas melting-infrared absorption method is used.

The outline of the sample preparation procedure is as follows.
Prepare a copper wire made of oxygen-free copper with a diameter of 11.5 mm and the above-mentioned iron-based material, and a tape with an appropriate thickness. The tape is wound around the outer periphery of the copper wire and fixed by welding. Is made.
The above-mentioned preparation material is passed through a wire drawing die, drawn and tightened to produce a composite material.
Using a wire drawing die or a rolling roller having an appropriate shape and size for the composite material, the wire material is drawn and rolled until the shape and size of the wire becomes the shape and size (major axis and minor axis) shown in Table 1 Apply processing.
A wire having an ellipse in shape (outer shape) includes a process of drawing using an ellipse drawing die and rolling using a hole roll.
In the processing step, when wire drawing or rolling is repeated until a predetermined shape (outer shape) and size are obtained, intermediate heat treatment is performed after an appropriate pass, and processing and heat treatment are repeated.
After the final heat treatment is performed on the obtained coated wire including the copper wire and the coating made of the iron-based material, an insulating layer (thickness: 50 μm) is formed. The insulating layer is formed by applying and baking a polyamide-imide resin insulating paint on the surface of the wire after the final heat treatment.
Through the above steps, the wire for a coil is provided with an annular or frame-like magnetic body layer made of an iron-based material on the entire surface of the conductor wire (copper wire) and an insulating layer on the outer periphery of the magnetic body layer. Is obtained.

A plurality of types of iron-based material tapes having different thicknesses are prepared, and the thickness and area ratio of the magnetic layer are adjusted to some extent. In this test, the thickness of the tape is about 0.8 mm to 2.0 mm.
Sample No. 1-2 to 1-4, 1-12 to 1-14, 1-22 to 1-24, 1-32 to 1-34, 1-112 to 1-114, 1-132 to 1-134 (hereinafter, For these samples), the thickness of the magnetic layer is adjusted by selecting the shape of the wire drawing dies and adjusting the rolling conditions. In this test, when measuring the loss described later, the thickness of the magnetic layer provided in the region disposed substantially parallel to the magnetic flux on the outer peripheral surface of the conductor wire is larger than the thickness of the magnetic layer in the other region. Adjust to be thicker.
The temperature of the final heat treatment is selected from the range of 200 ° C. or more and 500 ° C. or less, and the average crystal grain size of pure copper constituting the conductor wire is adjusted. In the above temperature range, the average crystal grain size tends to be smaller as the temperature is lower.

Evaluation performed for each prepared sample is as follows.
(Measurement of shape and size)
Observe the cross-section of the coil wire rod of each sample with an optical microscope. From the photographed micrograph, the size of the coil wire rod (excluding the insulating layer), 16 points or more at equal intervals in the circumferential direction of the magnetic layer The average value ta of the measured thickness, the maximum thickness tx of the magnetic layer, and the minimum thickness tn are measured.
The magnitude | size of the wire material for coils of each sample is shown by the length of a short side, and the length of a long side. In a round line (diameter) having a circular shape and a square line having a square shape, the length of the long side is equal to the length of the short side. In the case of an elliptical line, the major axis is the long side and the minor axis is the short side.
A thickness ratio (= tx / tn) is obtained from the maximum thickness tx and the minimum thickness tn of the magnetic layer. Sample No. with a thickness ratio of 1.0. In all of 1-1, 1-11, 1-21, 1-31, 1-101, 1-111, 1-131, and 1-135, the thickness of the magnetic layer is uniform over the entire circumference. It means that. These samples (hereinafter sometimes referred to as a uniform thickness sample group) include a magnetic layer having a uniform thickness over the entire circumference of the conductor wire.
For the coil wire, the ratio (area ratio) of the cross-sectional area of the magnetic layer to the total cross-sectional area of the conductor wire and the magnetic layer excluding the insulating layer was determined. The area ratio is calculated by performing image processing on the micrograph, extracting the conductor wire and the magnetic layer based on the material, and obtaining the total cross-sectional area and the cross-sectional area of the magnetic layer, respectively. A commercially available processing apparatus can be used for image processing.
For the coil wire of each sample, the shape of the wire, the length of the long side (mm) and the length of the short side (mm), the material of the magnetic layer, the maximum thickness tx (μm), the thickness ratio, the area ratio (%) Is shown in Table 1.
In addition, the coil wire of any sample is provided with an annular or frame-like magnetic body layer so as to cover the entire circumference of the conductor wire in the cross section.

(Component analysis)
With respect to the sample using carbon steel as the iron-based material, the components of the carbon steel constituting the magnetic layer were examined, and the total content (mass%) of carbon, phosphorus and sulfur in the carbon steel is shown in Table 1. Table 1 shows the results of examining materials other than carbon steel. Here, ICP emission spectroscopic analysis is used for component analysis, but atomic absorption spectrophotometry can also be used.

(Measurement of saturation magnetic flux density)
The magnetic flux density-magnetic field curve was measured using a vibrating sample magnetometer (BHV-5, manufactured by Riken Denshi Co., Ltd.), the saturation magnetic flux density of the coil wire of each sample was obtained, and the measured value was used as a magnetic material. Find the saturation flux density of the layer. The saturation magnetic flux density is obtained by dividing the measured magnetization M by the volume of the magnetic layer. Table 1 shows the saturation magnetic flux density (T).
Further, Bs × (t / w) is obtained by assuming that the obtained saturation magnetic flux density is Bs, the maximum width (here, long side) of the coil wire is w, and the thickness of the magnetic layer (here, average value ta) is t. The results are shown in Table 1.

(Measurement of specific resistance)
For the coil wire of each sample, the specific resistance (μΩ · cm) of the magnetic layer was measured using a four-terminal method, and the results are shown in Table 1. Here, as the test piece for measurement, a ribbon having a length of 150 mm cut out from the tape of the iron-based material described above is used. A test piece may be cut out from the magnetic layer of each sample.

(Measurement of hardness)
For the coil wire of each sample, the Vickers hardness Hv of the magnetic layer was measured, and the results are shown in Table 1. Here, although the test specimen for measurement was cut out from the magnetic layer of each sample, the above-described iron-based material tape can be cut out and used. A commercially available Vickers hardness tester can be used for the measurement of hardness.

(Measurement of loss)
The measurement circuit shown in FIG. 5 is configured, and the loss of the coil wire of each sample is obtained using this measurement circuit. A measurement circuit 100 shown in FIG. 5 includes a C-shaped magnetic core 110 having a gap 111 formed therein, a primary coil 121 and a secondary coil 122 wound around the magnetic core 110, and a signal generator 131. -H analyzer 130 is provided.

The loss of the coil wire is measured as follows.
The measurement sample S obtained by cutting the coil wire into strips is inserted into the gap 111 of the magnetic core 110. As shown in FIG. 5, the measurement sample S is inserted into the gap 111 so that the long side of the measurement sample S is parallel to the magnetic flux passing through the magnetic core 110 (here, the vertical direction).
An excitation signal is generated from the signal generator 131 of the BH analyzer 130, an excitation current i ₁ is passed through the primary coil 121 via the amplifier 132, and an alternating magnetic field is generated in the gap 111. From the AC resistance component obtained by measuring the exciting current i ₁ flowing through the resistor 133 and the induced voltage V ₂ generated at both ends of the secondary coil 122 when the measurement frequency and magnetic flux density of the AC magnetic field are changed, Find the loss.
Here, a comparative sample consisting only of a copper wire having substantially the same material, shape and size as the conductor wire in the coil wire of each sample and having no magnetic layer is prepared. Also measure the loss. The loss of the coil wire of each sample was evaluated as a relative value (%) with respect to 100 as the loss in the comparative sample, and the results are shown in Table 1.

(Measurement of average crystal grain size)
The cross section of the coil wire of each sample is observed with an optical microscope to determine the average crystal grain size (μm). Here, the cross section is etched to expose the crystal structure from the cross section of the conductor wire, and a micrograph (magnification: 25 to 200 times) is obtained. For this micrograph, the average grain size is measured based on the cutting method described in “Method for testing grain size of drawn copper products” defined in JIS H 0501 (1986). This average crystal grain size is defined as the average crystal grain size of the conductor wire, and the results are shown in Table 1.

(Tensile test)
The coil wire of each sample was subjected to a tensile test using a tensile testing machine (manufactured by Shimadzu Corporation, AG-5000D) to measure a stress-strain curve, and 0.2% proof stress (MPa) and elongation at break ( %) And the results are shown in Table 1. The distance between chucks in this tensile test is 250 mm, and the crosshead speed is 50 mm / min.

(Insulation)
For the coil wire of each sample, the insulating properties of the insulating layer were examined, and the results are shown in Table 1.
Here, an electrode is disposed at an appropriate position in the middle of the coil wire to be sent and in the vicinity of the coil wire, voltage is applied to the coil wire, and the number of energizations is counted. When there is a defect in the insulating layer, a current is applied between the conductor wire of the coil wire and the electrode, and the number of energizations increases as the number of defects increases. Therefore, the number of energizations can be regarded as the number of defects. Table 1 shows the number of energizations with respect to the dose (ton) as inspection defects (pieces / t). The coil wire is grounded.

  When the coil wire of each sample was examined using the above-mentioned micrograph of the optical microscope used for measuring the maximum thickness tx, etc., all the non-uniform thickness sample groups were thicker than the average thickness ta. Has a thick portion and a thin portion having an average thickness ta or less, and it can be said that the thickness is different when the magnetic layer is viewed in the circumferential direction.

  As shown in Table 1, it can be seen that by providing the magnetic layer, the loss is lower than that of the comparative sample having no magnetic layer. Here, the coil wire material of any sample is about half or less of the loss when there is no magnetic layer, and many samples are about 1/4 or less. In particular, Sample No. provided with a steel-containing layer containing carbon steel in the magnetic layer. The coil wires of 1-1 to 1-4, 1-11 to 1-14, 1-21 to 1-24, and 1-31 to 1-34 are sample Nos. Provided with pure iron layers. 1-101 and Sample No. with permalloy layer. Compared with 1-111 to 1-114, the loss is lower. The reason for this is that eddy currents generated in the steel-containing layer itself can be reduced because the specific resistance is higher than that of pure iron, and the saturation magnetic flux density is higher than that of permalloy, so that a sufficient amount of magnetic flux can be passed through the steel-containing layer, and This is probably because the generated eddy current was reduced.

  It can also be seen that carbon steel has lower hardness than permalloy or permendur. Therefore, it can be said that the sample coil wire provided with the steel-containing layer is easy to bend and has excellent coil formability. On the other hand, Sample No. provided with a permendur layer. It can be said that the wire materials for coils 1-131 to 1-134 are low in loss but hard and inferior to the wire materials including the steel-containing layer in terms of coil formability.

  Among the coil wire rods of the sample including the steel-containing layer, in particular, when the total amount of carbon, phosphorus and sulfur in the carbon steel is small, preferably 0.3% by mass or less, when the insulating layer is provided. It turns out that it is excellent also in insulation. The reason for this is that it is difficult to cause embrittlement such as blowholes and hydrogen embrittlement during welding, and it is possible to form a preparatory material with excellent surface properties. This is probably because the occurrence of pinholes and blisters was reduced.

  From these facts, the sample coil wire provided with the steel-containing layer is expected to form a low-loss coil and to be excellent in coil manufacturability. In addition, when the insulating layer is provided, it is expected that the insulating property of the coil is excellent.

  In addition, in the case where a magnetic layer of the same component is provided, the thickness is provided when the ratio between the minimum thickness and the maximum thickness (thickness ratio) satisfies 1.1 or more. It can be seen that the loss can be further reduced when the ratio is 1.0, that is, when the thickness is uniform over the entire area of the magnetic layer. It can also be seen that the loss can be further reduced as the thickness ratio increases (for example, 1.5 or more). Furthermore, even when the thickness of the magnetic layer of the uniform thickness sample group is approximately the same as the maximum thickness of the sample having the thick portion, it can be said that the loss is reduced in the sample having the thick portion.

The reason why such a result was obtained is as follows.
・ By arranging the thick part parallel to the magnetic flux, the cross-sectional area of the magnetic path can be secured sufficiently large, and the magnetic flux flowing through the thick part can be reduced sufficiently to reduce the magnetic flux that flows through the conductor wire. The provision of the thin portion reduced the eddy current that can occur in the magnetic layer itself. The area ratio of the magnetic layer satisfies 3% to 40%, and Bs × (t / w) ≧ 0. By satisfying 01T or more, and further 0.1T or more, it was possible to have a sufficient magnetic layer for the conductor wire.

  In addition, when the average crystal grain size of the conductor wire is 200 μm or less, the 0.2% proof stress is 60 MPa or more, the elongation at break is 5% or more, and further 10% or more here, and has excellent mechanical properties. I understand that If the average crystal grain size is 150 μm or less, the 0.2% proof stress is 80 MPa or more, and many samples have 90 MPa or more. If the average crystal grain size is 100 μm or less, the 0.2% proof stress is 100 MPa or more, and if the average crystal grain size is 70 μm or less, the 0.2% proof stress is 120 MPa or more, which is higher strength. In this test, the elongation at break is 10% or more. Therefore, it can be seen that it is excellent in elongation while having higher strength.

  The present invention is not limited to these exemplifications, but is defined by the scope of claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

  The coil wire of the present invention can be used for coils provided in motors, transformers (transformers), reactors, IH heaters (induction heating devices), and the like.

DESCRIPTION OF SYMBOLS 10 Coil wire 11 Conductor wire 12 Magnetic layer 13 Insulating layer 12a Thick part 12b Thin part 21 Material wire 22 Magnetic member 30 Composite material 40 Work material S Measurement sample (Coil wire)
DESCRIPTION OF SYMBOLS 100 Measurement circuit 110 Magnetic core 111 Gap 121 Primary coil 122 Secondary coil 130 BH analyzer 131 Signal generator 132 Amplifier 133 Resistance

Claims (7)

A conductor wire;
A magnetic layer formed of a magnetic material on the outer periphery of the conductor wire,
The magnetic layer includes a steel-containing layer formed of carbon steel ,
The steel-containing layer includes a non-uniform layer having a thick portion and a thin portion having different thicknesses in a circumferential direction in a cross section perpendicular to the axial direction of the conductor wire,
Maximum thickness ratio is 1.1 or more der Ru wire coil of the thick portion to the minimum thickness of the thin portion. The coil wire according to claim 1, wherein the total content of carbon, phosphorus, and sulfur in the carbon steel is more than 0 and 0.3 mass% or less. The magnetic layer coil wire according to claim 1 or claim 2 ratio of cross-sectional area is 40% or less than 3% of the relative cross-sectional area combined with the magnetic layer and the conductor wire. 2. The saturation magnetic flux density of the magnetic layer is Bs, the maximum width of the coil wire is w, and the thickness of the magnetic layer is t, Bs × (t / w) ≧ 0.01T is satisfied. The coil wire according to any one of claims 3 to 4 . Coil wire according to any one of claims 1 to 4 average crystal grain size of the metal constituting the conductor wire is 200μm or less. 0.2% proof stress of not less than 60 MPa, the coil wire as claimed in any one of claims 5 breaking elongation of 5% or more. Coil wire according to any one of claims 1 to 6 comprising an insulating layer on the outer periphery of the conductor wire.

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