Soft magnetic composite plate, iron core and rotating electric machine using said soft magnetic composite plate

Abstract

The present invention provides a soft magnetic composite material plate capable of reducing iron loss more than conventional plates without significantly impairing the magnetization characteristics inherent in soft magnetic materials, and an iron core and a rotating electric machine using the soft magnetic composite material plate. [Solution] The soft magnetic composite plate of the present invention is a composite of a soft magnetic material and an electrically insulating coating, wherein the soft magnetic material has a filament shape, the electrically insulating coating contains a lead-free glass composition and has a linear expansion coefficient that is 3 ppm / K or more smaller than the linear expansion coefficient of the soft magnetic material, and comprises a soft magnetic composite wire in which the electrically insulating coating is formed on the surface of the filament-shaped soft magnetic material, and the soft magnetic composite wire is integrated so that the longitudinal direction of the soft magnetic composite wire is aligned in the in-plane direction of the plate shape of the soft magnetic composite plate.

Description

[Technical Field]

[0001] The present invention relates to soft magnetic material technology, and more particularly to a soft magnetic composite plate exhibiting low iron loss, an iron core using the soft magnetic composite plate, and a rotating electric machine. [Background technology]

[0002] Laminated cores made by laminating multiple soft magnetic material sheets (e.g., 0.01 to 3 mm thick), such as electromagnetic pure iron sheets or electromagnetic steel sheets, are widely used in electrical machinery devices (e.g., rotating electrical machines and transformers).From the perspective of protecting the global environment, the application fields of electrical machinery devices that use soft magnetic materials have been expanding in recent years, and as a result, there has been an increasing demand for higher output and higher efficiency in these electrical machinery devices.

[0003] When considering a rotating electric machine as an electromechanical device, its output is proportional to the product of the torque and rotation speed during operation, so increasing either the torque or rotation speed can increase output. Torque is proportional to the product of the magnetic flux density and the current value. To increase torque, it is desirable to use soft magnetic materials that achieve high saturation magnetic flux density Bs and / or high saturation magnetization Ms. Various methods of controlling the composition and microstructure of soft magnetic materials are being used to increase Bs / Ms.

[0004] When increasing the rotation speed during operation, the conversion efficiency between electrical energy and magnetic energy is important, and reducing the loss (iron loss Pi) in the soft magnetic material plate becomes a challenge. Reducing Pi also leads to reduced heat generation during operation. Pi is the sum of hysteresis loss and eddy current loss, and a small coercive force Hc is desirable to reduce hysteresis loss, while increasing electrical resistance and thinning the plate are effective in reducing eddy current loss.

[0005] Currently, Fe-Si alloy electrical steel sheets are widely used as a material that has a good balance between a relatively high Bs / Ms and a relatively low Pi. Fe-Co alloy sheets are known to have a higher Bs than Fe-Si alloy electrical steel sheets. In recent years, Fe (iron)-based amorphous alloy sheets and Fe-based nanocrystalline alloy sheets have also attracted attention as materials that have a lower Pi than Fe-Si alloy electrical steel sheets and Fe-Co alloy sheets.

[0006] On the other hand, since electromechanical devices using soft magnetic materials have a wide variety of applications and sizes, there has been active development of technology for the stable production of soft magnetic materials in order to meet the various required characteristics in the design of such electromechanical devices.

[0007] For example, in Patent Document 1 (JP 2022-113111), the alloy composition is represented by the formula (Fe 1-x A x ) a Si b B c Cu d M e where A is at least one of Ni and Co, and M is one or more selected from the group consisting of Nb, Mo, V, Zr, Hf, and W, and the atomic percentages are 82.4≦a≦86, 0.2≦b≦2.4, 12.5≦c≦15.0, 0.05≦d≦0.8, 0.4≦e≦1.0, and 0≦x≦0.1. The soft magnetic alloy ribbon has a structure in which crystal grains having a grain size of 60 nm or less exist in an amorphous phase, and has a saturation magnetic flux density of 1.74 T or more and an iron loss at 1 kHz and 1 T of 25 W / kg or less.

[0008] According to Patent Document 1, it is possible to obtain a soft magnetic alloy ribbon having a high saturation magnetic flux density and low iron loss, and a method for manufacturing the same. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2022-113111 Summary of the Invention [Problem to be solved by the invention]

[0010] As mentioned above, there is a growing demand for increasing the output power (e.g., power density W / kg) of electromechanical devices. Recently, increasing the rotation speed and / or frequency during operation has been promoted as a means of increasing the output power of electromechanical devices. However, increasing the rotation speed and / or frequency poses a major problem of energy loss and efficiency reduction due to the Pi of soft magnetic materials. In other words, in order to increase the power density and efficiency of electromechanical devices, it is desirable for soft magnetic materials to have both a high Bs / Ms and a low Pi.

[0011] The present invention has been made to achieve the above-mentioned object, and its primary object is to provide a soft magnetic composite sheet that can reduce Pi more than conventionally without significantly impairing the Bs / Ms characteristics inherent in soft magnetic materials, and an iron core and a rotating electric machine that use the soft magnetic composite sheet. [Means for solving the problem]

[0012] (I) One aspect of the present invention is a soft magnetic composite plate in which a soft magnetic material and an electrically insulating coating are combined, the soft magnetic material has a filament shape; the electrically insulating coating contains a lead-free glass composition and has a linear expansion coefficient that is at least 3 ppm / K smaller than the linear expansion coefficient of the soft magnetic material; A soft magnetic composite wire is formed by forming the electrically insulating coating on the surface of the soft magnetic material in a filament shape, The soft magnetic composite wires are integrated so that their longitudinal directions are aligned in the in-plane direction of the plate shape of the soft magnetic composite material plate. The present invention provides a soft magnetic composite plate characterized by the above-mentioned.

[0013] In the present invention, the linear expansion coefficients of the soft magnetic material and the electrical insulating coating are defined as the average linear expansion coefficients from room temperature to the glass transition point Tg of the electrical insulating coating.

[0014] In the present invention, the following improvements and modifications can be freely combined and added to the soft magnetic composite material plate (I) according to the present invention. (i) The thickness of the soft magnetic composite plate is 0.01 mm or more and 3 mm or less, the space factor of the soft magnetic material is 80 volume % or more, and the average thickness of the electrical insulating coating is less than 10% of the diameter of the equivalent area circle of the cross section of the filament shape. (ii) the glass composition, when expressed as nominal components in terms of oxides, contains 40% by mass or more and 70% by mass or less of V2O5 (vanadium oxide) and 10% by mass or more and 35% by mass or less of P2O5 (phosphorus oxide), and the sum of the V2O5 and the P2O5 is 50% by mass or more and 98% by mass or less; The material contains two or more elements selected from the group consisting of BaO (barium oxide), Sb2O3 (antimony oxide), WO3 (tungsten oxide), ZnO (zinc oxide), K2O (potassium oxide), Fe2O3 (iron oxide), TeO2 (tellurium oxide), Ag2O (silver oxide), and Li2O (lithium oxide) in a total amount of 2% by mass or more and 50% by mass or less, with the remainder being unavoidable impurities, The softening point of the glass composition is 500° C. or lower. (iii) the electrically insulating coating contains no more than 75% by volume of a filler of oxide particles; The filler is one or more of the group consisting of SiO2 (silicon oxide), ZrO2 (zirconium oxide), Al2O3 (aluminum oxide), Nb2O5 (niobium oxide), ZrSiO4 (zirconium silicate), Zr2(WO4)(PO4)2 (zirconium tungstate phosphate), 2MgO·2Al2O3·5SiO2 (cordierite), 3Al2O3·2SiO2 (mullite), and LiAlSiO4 (eucryptite). (iv) The linear expansion coefficient of the electrical insulating coating is less than 10 ppm / °C. (v) The soft magnetic material has a tensile strain in the range of 10 μST to 1000 μST along its longitudinal direction.

[0015] (II) Another aspect of the present invention is an iron core made of a laminate of soft magnetic composite plates, The soft magnetic iron alloy plate is the soft magnetic iron alloy plate according to the present invention, The soft magnetic composite wires are arranged so that the longitudinal direction of the soft magnetic composite wires is parallel to the magnetization direction applied to the soft magnetic composite plate. The present invention provides an iron core characterized by the above-mentioned.

[0016] (III) Yet another aspect of the present invention is a rotating electric machine having an iron core, The present invention also provides a rotating electric machine, wherein the iron core is the iron core according to the present invention. [Effects of the Invention]

[0017] According to the present invention, it is possible to provide a soft magnetic composite plate that can reduce Pi more than conventionally without significantly impairing the Bs / Ms characteristics that the soft magnetic material originally has, and an iron core and a rotating electric machine that use the soft magnetic composite plate.

[0018] Problems, configurations, and effects other than those described above will become clear from the description of the embodiments below. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a partially enlarged perspective schematic view showing an example of the structure of a soft magnetic composite core according to the present invention; [Figure 2] 1 is a schematic perspective view showing an example of an iron core according to the present invention. [Figure 3A] FIG. 1 is a schematic perspective view showing an example of a stator of a rotating electric machine. [Figure 3B] FIG. 2 is an enlarged cross-sectional schematic view of a slot region of the stator. [Figure 4]1 is an example of a chart obtained during the temperature rise process of differential thermal analysis of a glass composition used as an electrical insulating coating in the present invention. [Figure 5] 1 is a flow diagram showing an outline of a method for manufacturing an iron core using a soft magnetic composite plate according to the present invention. [Figure 6] FIG. 2 is a plan view schematically illustrating an example of an arrangement of soft magnetic composite wires in a soft magnetic composite plate according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] [Basic concept of the present invention] As mentioned above, Pi is the sum of hysteresis loss and eddy current loss, and increasing the electrical resistance of soft magnetic material sheets and reducing their thickness are considered effective ways to reduce eddy current loss. The inventors have conducted various studies on technologies to further reduce Pi in soft magnetic material sheets.

[0021] In this research, it was found that increasing the electrical resistance by partially replacing the constituent components of soft magnetic materials and simply thinning the soft magnetic material tend to lead to a decrease in the Bs / Ms characteristics. On the other hand, it was found that applying tensile strain in the in-plane direction of the soft magnetic material plate may be able to reduce hysteresis loss. Furthermore, it was found that it is preferable to align the tensile strain applied to the soft magnetic material plate with the magnetization direction of the soft magnetic material plate.

[0022] The inventors of the present invention have further intensively researched means for reducing Pi below conventional levels without significantly impairing the inherent Bs / Ms characteristics of soft magnetic materials. As a result, they have found a possible solution in a method in which soft magnetic material is filamentized to reduce the eddy current area, and an electrically insulating coating having a smaller linear expansion coefficient than the soft magnetic material is formed on the surface of the soft magnetic filaments to reduce hysteresis loss, thereby forming a soft magnetic composite wire that is subjected to tensile strain, and then bundling the soft magnetic composite wires to form a plate shape. The present invention was completed based on this finding.

[0023] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the specific embodiments described, and can be appropriately combined with or improved on known techniques without departing from the technical concept of the invention.

[0024] [Soft magnetic composite plate and iron core of the present invention] FIG. 1 is a partially enlarged perspective schematic view showing an example of the structure of a soft magnetic composite plate according to the present invention, and FIG. 2 is a perspective schematic view showing an example of an iron core according to the present invention. As shown in FIG. 1, a soft magnetic composite plate 20 according to the present invention is formed by bundling a plurality of soft magnetic composite wires 10, each of which has an electrically insulating coating 2 formed on the surface of a filament-shaped soft magnetic material (soft magnetic filament 1), and integrally molding the bundled wires into a plate shape. The soft magnetic composite plate 20 can be suitably used, for example, as a soft magnetic plate for a split iron core. Furthermore, as shown in FIG. 2, an iron core 30 according to the present invention is formed by stacking a plurality of soft magnetic composite plates 20 and integrating them.

[0025] In Fig. 1, the cross section of the soft magnetic composite plate 20 shows four layers of soft magnetic filaments 1 stacked in a square arrangement in the plate thickness direction, but the present invention is not limited to this. For example, the soft magnetic filaments 1 may be stacked in one to three layers, or five or more layers, or may be arranged hexagonally. There is no particular limitation on the thickness of the soft magnetic composite plate 20, but when used as a constituent material for a laminated iron core, a thickness of 0.01 mm or more and 3 mm or less is preferable.

[0026] [Stator and rotating electrical machine using the soft magnetic composite material plate of the present invention] Fig. 3A is a schematic perspective view showing an example of a stator of a rotating electric machine, and Fig. 3B is an enlarged schematic cross-sectional view of a slot region of the stator. Note that the cross-sectional view refers to a cross section perpendicular to the rotation axis direction (a cross section whose normal is parallel to the axial direction). In a rotating electric machine, a rotor (not shown) is disposed radially inside the stator of Figs. 3A and 3B.

[0027] 3A and 3B, the stator 40 has stator coils 41 wound in multiple stator slots 31 formed on the inner periphery of the core 30. The stator slots 31 are spaces that are arranged at a predetermined circumferential pitch around the circumferential direction of the core 30 and penetrate the core 30 in the axial direction, with slits 32 opening in the innermost periphery and extending in the axial direction. The areas separating adjacent stator slots 31 are called teeth 33 of the core 30, and the parts of the inner periphery tip areas of the teeth 33 that define the slits 32 are called tooth claw portions 34. The outer periphery parts that connect adjacent teeth 33 are called yokes 35 of the core 30.

[0028] The stator coil 41 is usually made up of a plurality of segment conductors 42. For example, in Figures 3A and 3B, the stator coil 41 is made up of three segment conductors 42 corresponding to the U-phase, V-phase, and W-phase of a three-phase AC. Furthermore, from the viewpoint of preventing partial discharge between the segment conductors 42 and the iron core 30 and partial discharge between the phases (U-phase, V-phase, W-phase), the outer periphery of each segment conductor 42 is usually covered with an electrical insulating material 43 (for example, insulating paper or enamel coating).

[0029] The rotating electric machine referred to here is a rotating electric machine that uses an iron core 30 made of the soft magnetic composite material plate 20 of the present invention. The iron core 30 can reduce Pi more than conventionally without significantly impairing the Bs / Ms characteristics inherent in soft magnetic materials, and therefore can suitably accommodate higher rotation speeds and higher frequencies while suppressing energy loss and efficiency reduction of the rotating electric machine. As a result, the rotating electric machine can improve its power density more than conventionally.

[0030] The structure of the soft magnetic composite plate 20 will now be described in detail.

[0031] (soft magnetic filament) Although there is no particular limitation on the soft magnetic material used in the present invention, from the viewpoint of Bs / Ms, it is preferable to use a material that exhibits a higher Bs / Ms than Fe-Si alloy-based electrical steel sheet (e.g., electromagnetic pure iron material, Fe-Co alloy material, Fe-N alloy material, Fe-Co-N alloy material, etc.). Also, from the viewpoint of Pi, it is preferable to use a material that is suitable for reducing Pi (e.g., Fe-Co alloy material, Fe-Co-N alloy material, Fe-based amorphous alloy material, Fe-based nanocrystalline alloy material, etc.).

[0032] In the present invention, the Fe-based nanocrystalline alloy material basically means an alloy material in which an Fe-based nanocrystalline alloy phase is finely dispersed in a matrix of an Fe-based amorphous alloy phase, but it may also be an alloy material composed only of an Fe-based nanocrystalline alloy phase.

[0033] Regarding the filament shape, Fig. 1 depicts a case where the filament cross section is rectangular, but the present invention is not limited thereto. For example, the filament cross section may be circular, elliptical, hexagonal, or flat. There are no particular limitations on the filament diameter, but assuming that the final thickness of the soft magnetic material plate is 0.01 to 3 mm, it is preferable to control the filament diameter so that the diameter of the equivalent area circle of the cross section is 0.008 mm to 2.5 mm.

[0034] Furthermore, when the soft magnetic composite plate 20 of the present invention is used as a constituent material of a laminated iron core, in order to ensure desirable magnetic properties (e.g., magnetic flux density of the iron core), it is preferable that the space factor of the soft magnetic filaments 1 in the soft magnetic composite plate 20 be 80 volume % or more.

[0035] (electrical insulating coating) The electrical insulating coating 2 preferably has a linear expansion coefficient smaller than that of the soft magnetic filament 1 (usually 10 ppm / K or greater). When the electrical insulating coating 2 has a linear expansion coefficient smaller than that of the soft magnetic filament 1, compressive stress is applied to the electrical insulating coating 2 when the electrical insulating coating 2 is cooled from its formation temperature to room temperature, and tensile stress can be applied to the soft magnetic filament 1.

[0036] More specifically, the electrical insulating coating 2 is preferably made of a material that contains a lead-free glass composition and has a linear expansion coefficient that is at least 3 ppm / K smaller than that of the soft magnetic filaments 1. The linear expansion coefficient of the electrical insulating coating 2 is more preferably at least 5 ppm / K smaller, and even more preferably at least 10 ppm / K smaller, than that of the soft magnetic material.

[0037] Research by the present inventors has revealed that applying a tensile strain within the elastic deformation range to the soft magnetic filament 1 in the longitudinal direction can significantly reduce Pi. On the other hand, applying a tensile strain within the plastic deformation range to the soft magnetic filament 1 increases Pi. The amount of strain applied to the soft magnetic filament 1 is preferably in the range of 10 μST to 1000 μST (where ST means the amount of strain), more preferably in the range of 15 μST to 800 μST, and even more preferably in the range of 20 μST to 700 μST.

[0038] In order to ensure the space factor of the soft magnetic filaments 1 in the soft magnetic composite plate 20, the average thickness of the electrical insulating coating 2 is preferably less than 10% of the diameter of the equivalent area circle of the cross section of the soft magnetic filaments 1.

[0039] 4 is an example of a chart (DTA curve) obtained during the temperature rise process of differential thermal analysis (DTA) for the glass composition used as an electrical insulating coating in the present invention. As shown in FIG. 4, the onset temperature of the first endothermic peak is taken as the glass transition point Tg (viscosity = 10 13.3 The peak temperature of the first endothermic peak is the sag point Td (viscosity = 10 11.0 The peak temperature of the second endothermic peak is the softening point Ts (viscosity = 10 7.65 The peak temperature of the first exothermic peak is defined as the crystallization peak temperature Tcp. These temperatures are determined by the tangent method.

[0040] A glass composition with lower characteristic temperatures Tg, Td, and Ts is more likely to soften and flow at low temperatures, allowing the electrical insulating coating 2 to be formed at low temperatures. From the standpoint of workability and temperature controllability, it is desirable to form the electrical insulating coating 2 at a temperature approximately 20 to 50°C higher than Ts. On the other hand, if the glass composition crystallizes, the softening and flow properties are significantly impaired and the adhesion of the coating is also greatly reduced, so the coating must be formed at a temperature below Tcp.

[0041] For these reasons, the glass composition constituting the electrical insulating coating 2 preferably has a characteristic temperature such that the temperature difference between Ts and Tcp is at least about 20 to 50° C. More specifically, the glass composition used in the present invention preferably has a Ts of 500° C. or less, more preferably 450° C. or less, and even more preferably 420° C. or less.

[0042] Since it is undesirable for the electrical insulating coating 2 of the soft magnetic composite sheet 20 to soften and flow when the electromechanical device is used, it is preferable to set the Ts of the glass composition to be higher than the temperature at which the electromechanical device is used when using the soft magnetic composite sheet 20 of the present invention. For example, when the operating temperature of the electromechanical device is 150°C, it is preferable that the Ts of the glass composition be higher than 150°C.

[0043] From the viewpoint of environmental protection, the glass composition used in the present invention is preferably a lead-free glass composition, and when the nominal components are expressed as oxides, it contains 40% by mass or more and 70% by mass or less of V2O5 and 10% by mass or more and 35% by mass or less of P2O5, the total of V2O5 and P2O5 being 50% by mass or more and 98% by mass or less, and it contains two or more members selected from the group consisting of BaO, Sb2O3, WO3, ZnO, KO, Fe2O3, TeO2, Ag2O, and Li2O in a total amount of 2% by mass or more and 50% by mass or less, and the balance consisting of unavoidable impurities.

[0044] In the present invention, "lead-free" does not mean that lead components are intentionally contained, but it is acceptable that lead components are inevitably contained within a range below the value specified by the laws and regulations of each country.

[0045] In the glass composition used in the present invention, V2O5 is a component that contributes to lowering the glass softening flow temperature. P2O5 is a component that can form the glass skeleton and also contributes to suppressing crystallization of glass. BaO, Sb2O3, WO3, ZnO, K2O, and Fe2O3 are components that contribute to improving the moisture and water resistance of glass and suppressing crystallization. TeO2 and Ag2O, like V2O5, are components that contribute to lowering the glass softening flow temperature. Li2O is a vitrifying component that contributes to improving adhesion and adhesion.

[0046] By controlling the above components and their contents, a lead-free glass composition having a desired characteristic temperature can be obtained. However, if the difference in the linear expansion coefficient between the soft magnetic filament 1 and the electrical insulating coating 2 is too small, sufficient tensile strain cannot be imparted to the soft magnetic filament 1.

[0047] Therefore, in order to control the linear expansion coefficient of the electrical insulating coating 2, a filler may be mixed into the lead-free glass composition. Naturally, mixing a filler is not essential. Oxide particles are preferred as the filler in terms of compatibility with the oxide glass. For example, one or more selected from the group consisting of SiO2, ZrO2, Al2O3, Nb2O5, ZrSiO4, Zr2(WO4)(PO4)2, 2MgO·2Al2O3·5SiO2, 3Al2O3·2SiO2, and LiAlSiO4 can be suitably used. The oxide particles are preferably spherical (e.g., with a minor axis / major axis ratio of 0.8 or more).

[0048] The average particle size of the filler is preferably 0.1 μm to 10 μm, more preferably 0.5 μm to 5 μm. When a filler is mixed, the mixing ratio is preferably 75 vol% or less, more preferably 70 vol% or less, and even more preferably 5 vol% to 70 vol%.

[0049] Mixing a filler into the glass composition to form the electrical insulating coating 2 has the advantage of being able to control the linear expansion coefficient of the electrical insulating coating 2 and also the viscosity at the time of softening and flowing. Another advantage is that controlling the average particle size and mixing ratio of the filler makes it easier to control the spacing between the soft magnetic filaments 1 (i.e., the thickness of the electrical insulating coating 2) when bundling the soft magnetic filaments 1 and molding them into an integrated structure.

[0050] [Soft magnetic composite plate and method of manufacturing an iron core using the soft magnetic composite plate] Fig. 5 is a flow diagram showing an outline of a method for manufacturing an iron core using a soft magnetic composite material plate according to the present invention. As shown in Fig. 5, first, a soft magnetic filament preparation step S1 is performed to prepare a soft magnetic filament 1, and a paste preparation step S2 is performed to prepare a paste that will be the basis for the electrical insulating coating 2. The order of steps S1 and S2 does not matter.

[0051] Next, the paste prepared in step S2 is applied to the surface of the soft magnetic filament 1 prepared in step S1 to form a soft magnetic composite wire precursor that serves as an intermediate material, and then an electrical insulating coating formation step S3 is performed in which the soft magnetic composite wire precursor is subjected to a predetermined heat treatment to form an electrical insulating coating 2. Through this step, a soft magnetic composite wire 10 is obtained.

[0052] Next, a soft magnetic composite plate forming step S4 is performed in which the soft magnetic composite wires 10 are bundled and molded while being subjected to a predetermined heat treatment to form the soft magnetic composite plate 20. Through this step, the soft magnetic composite plate 20 according to the present invention is obtained.

[0053] Next, an iron core formation step S5 is performed in which a plurality of soft magnetic composite plates 20 are stacked to form the iron core 30. At this time, although it is not an essential process, it is more preferable to subject the entire stacked soft magnetic composite plates 20 to a predetermined heat treatment to soften, flow, and harden the electrical insulating coating 2 again, thereby joining the soft magnetic composite plates 20 together. Through this step, the iron core 30 according to the present invention is obtained.

[0054] Each step will be described in more detail.

[0055] Step S1 is a step of preparing a soft magnetic filament 1. This step is not particularly limited as long as the desired soft magnetic filament 1 can be prepared, and a conventional metal processing method (for example, wire drawing from a rod material or cutting from a thin plate material) may be used, or the soft magnetic filament 1 may be procured from a commercially available soft magnetic material wire.

[0056] Step S2 is a step of preparing a paste that is the base of the electrical insulating coating 2. The paste is obtained by mixing a powder of the aforementioned lead-free glass composition or a frit obtained by mixing the powder with the aforementioned filler, with a resin binder and a solvent.

[0057] When a filler is mixed into the frit, as described above, the lead-free glass composition is preferably 25% by volume or more and 95% by volume or less, and the filler is preferably 5% by volume or more and 75% by volume or less. As a resin binder for the paste, for example, nitrocellulose can be preferably used. As a solvent for the paste, for example, butyl carbitol acetate or α-terpineol can be preferably used. The mixing ratio of the resin binder and the solvent can be appropriately adjusted taking into consideration the workability when applying the glass paste.

[0058] In step S3, the paste prepared in step S2 is applied to the surface of the soft magnetic filament 1 prepared in step S1 to form a soft magnetic composite wire precursor that serves as an intermediate material, and then the soft magnetic composite wire precursor is subjected to a predetermined heat treatment to form an electrical insulating coating 2. In this way, a soft magnetic composite wire 10 is obtained.

[0059] The process for forming the soft magnetic composite wire precursor is not particularly limited to a coating method, as long as the thickness of the paste coating film (e.g., on the order of μm) can be controlled. The prescribed heat treatment pattern includes, for example, a drying process in which the coating film is heated and maintained at 120 to 200°C to dry out the moisture, binder components, and solvent components, followed by a firing process in which the coating film is heated and maintained at a temperature 20 to 50°C higher than the Ts of the lead-free glass composition used. The maximum temperature of the firing process is lower than the Tcp of the lead-free glass composition used. When an Fe-based amorphous alloy material or an Fe-based nanocrystalline alloy material is used as the soft magnetic material, the maximum temperature is lower than the secondary crystallization temperature of the material.

[0060] The second crystallization temperature of Fe-based amorphous alloy materials and Fe-based nanocrystalline alloy materials is defined as the higher of the two large exothermic peaks observed during the heating process when DTA (differential thermal analysis) is performed on Fe-based amorphous alloy materials. The lower of the two large exothermic peaks is considered to be the exothermic reaction where partial crystallization begins from the amorphous phase (the exothermic reaction where the nanocrystalline alloy phase begins to nucleate and crystallize), and this peak temperature is defined as the first crystallization temperature. The higher peak is considered to be the exothermic reaction where the original amorphous phase completely crystallizes and the nanocrystalline alloy phases begin to coalesce and coarsen.

[0061] After the electrical insulating coating 2 is formed by the firing process, when it is cooled, due to the difference in the linear expansion coefficients, compressive stress is applied to the electrical insulating coating 2 and tensile stress is applied to the soft magnetic filament 1. Ceramic materials are generally brittle to tensile stress but are very strong to compressive stress, so they can maintain / fix the soft magnetic filament 1 in a state where it is subjected to tensile strain.

[0062] In order to adjust the tensile strain of the soft magnetic filament 1, the treatment may be carried out in a state where a tensile stress is applied to the soft magnetic filament 1.

[0063] In step S4, a plurality of the soft magnetic composite wires 10 prepared in step S3 are bundled and molded while being subjected to a predetermined heat treatment, thereby forming a soft magnetic composite plate 20. In this step, it is preferable to determine the magnetization direction that will occur in the iron core 30 when the soft magnetic composite plate 20 is used as the iron core 30 of an electric machine device, and then bundle and mold the plurality of soft magnetic composite wires 10 so that the magnetization direction and the longitudinal direction of the soft magnetic composite wire 10 coincide with each other.

[0064] Fig. 6 is a schematic plan view showing an example of the arrangement of soft magnetic composite wires in a soft magnetic composite plate according to the present invention. As shown in Fig. 6, in the portions that will become the teeth 33 of the iron core 30, it is preferable to arrange the soft magnetic composite wires 10 so that the radial direction of the soft magnetic composite plate 20 coincides with the longitudinal direction of the soft magnetic composite wires 10, and in the portions that will become the yoke 35 of the iron core 30, it is preferable to arrange the soft magnetic composite wires 10 so that the circumferential direction of the soft magnetic composite plate 20 coincides with the longitudinal direction of the soft magnetic composite wires 10.

[0065] The method of integral molding is not particularly limited, but since heating is performed while molding (molding while heating), for example, hot pressing or hot isostatic pressing (HIP) can be suitably used. The heat treatment pattern in step S4 is basically the same as step S3, except that differences in heat capacity of the heat-treated articles are taken into consideration and a drying process is not required.

[0066] In addition, if precise control of the shapes of the parts that will become the teeth 33 of the iron core 30 and the parts that will become the yoke 35 is not performed in the integral molding process of step S4, an additional soft magnetic composite material plate shape processing step may be performed in which the integrally molded soft magnetic composite material plate 20 is shaped using a conventional metal processing method (e.g., laser processing, water jet processing, etc.).

[0067] Step S5 is a step of laminating multiple soft magnetic composite plates 20 to form the iron core 30. At this time, a predetermined heat treatment may or may not be applied to the entire laminated soft magnetic composite plate 20. If the predetermined heat treatment is performed to soften, flow, and harden the electrical insulating coating 2 again and join the soft magnetic composite plates 20 together, the entire iron core 30 can be integrated, which has the advantage of contributing to the miniaturization of the iron core 30 and improving its vibration resistance. The heat treatment pattern in step S5 is the same as that in step S4.

[0068] As in step S4, an iron core shape processing step for precisely controlling the iron core 30 into a desired shape may be additionally performed as part of this step. [Example]

[0069] The present invention will be explained in more detail below with reference to various experiments, however, the present invention is not limited to the configurations and structures described in these experiments.

[0070] [Experiment 1] (Preparation of soft magnetic materials SM-1 to SM-4) Soft magnetic materials SM-1 to SM-4 were prepared as materials for the soft magnetic filament 1. As the soft magnetic material SM-1, a commercially available Fe-based amorphous alloy plate (Magprost Co., Ltd., 1K101, thickness 25 μm, length 70 mm, width 20 mm) was prepared. As the soft magnetic material SM-2, a commercially available Fe-based nanocrystalline alloy plate (Magnet Institute Co., Ltd., NANOMET (registered trademark), NMAQ, thickness 25 μm, length 70 mm, width 20 mm) was prepared. Note that NMAQ is a soft magnetic material plate that becomes an Fe-based nanocrystalline alloy plate by a predetermined nanocrystallization heat treatment.

[0071] A homemade Fe-Co alloy plate (80 atomic % Fe-20 atomic % Co, 100 μm thick, 70 mm long, and 20 mm wide) was prepared as the soft magnetic material SM-3. An Fe-Co-N alloy plate (79.5 atomic % Fe-19.5 atomic % Co-1 atomic % N, 100 μm thick, 70 mm long, and 20 mm wide) was prepared as the soft magnetic material SM-4 by nitriding SM-3.

[0072] (Soft magnetic filaments SMF-1 to 4 available) The soft magnetic filaments SMF-1 to SMF-4 were prepared by cutting the soft magnetic materials SM-1 to SM-4 into pieces each having a width of 1 mm.

[0073] (Property investigation of soft magnetic materials SM-1 to SM-4) The crystallization temperatures of the prepared SM-1 and SM-2 were measured using a differential thermal analyzer (Hitachi High-Tech Corporation, model: TG / DTA6200). The results are shown in Table 1 below.

[0074] Based on the results of the DTA measurements, the influence on Pi was investigated after heat treatment of SM-1 and SM-2. Pi was also investigated for the prepared SM-3 and SM-4. Pi measurements were performed using a BH loop analyzer (IFG Corporation, IF-BH550) and the H coil method (compliant with JIS C 2556:2015) using a vertical yoke single sheet tester. Iron loss Pi under the conditions of magnetic flux density 1.0 T, frequency 400 Hz, and temperature 20°C -1.0 / 400 (unit: W / kg) and iron loss Pi under the conditions of magnetic flux density 1.0 T, frequency 10000 Hz, and temperature 20°C -1.0 / 10k (Unit: W / kg) was measured. The results are shown in Table 1.

[0075] [Table 1]

[0076] As shown in Table 1, SM-1 has a first crystallization temperature of 533°C and a second crystallization temperature of 557°C. SM-2 has a first crystallization temperature of 395°C and a second crystallization temperature of 514°C. SM-1 and SM-2 have very low Pi values ​​for heat treatment at a temperature (505°C) lower than the second crystallization temperature. -1.0 / 400 However, at 10000 Hz, Pi -1.0 / 10k It is confirmed that the Pi increases dramatically when heat treatment is performed at a temperature above the second crystallization temperature (700°C). -1.0 / 400On the other hand, in SMF-3 and SMF-4, the Pi is sufficiently low at 400 Hz. -1.0 / 400 However, at 10000 Hz, Pi -1.0 / 10k is confirmed to increase dramatically.

[0077] [Experiment 2] (Preparation of Glass Compositions G-1 to G-3) Glass compositions G-1 to G-3 were prepared, each having the nominal composition shown in Table 2 below. The nominal compositions in the table are expressed as the mass ratio of each component converted to oxide. The starting materials used were V2O5 (Kojundo Chemical Laboratory Co., Ltd., purity 99.9%), P2O5 (Kojundo Chemical Laboratory Co., Ltd., purity 99.9%), BaCO3 (Kojundo Chemical Laboratory Co., Ltd., purity 99.9%), and Sb2O3 (Fujifilm Wako Pure Chemical Industries, Ltd., purity 99.9%). As can be seen from the purity of the starting materials, the lead-free glass composition used in the present invention contains a certain amount of unavoidable impurities.

[0078] The platinum crucible containing the mixed raw material powder was placed in a glass melting furnace and heated to 900°C at a heating rate of 5°C / min to melt the mixed raw material powder. The mixture was then held for 1 hour while stirring with an alumina rod to homogenize the composition of the melt in the platinum crucible. The platinum crucible was then removed from the glass melting furnace, and the melt was poured into a graphite mold preheated to 300°C to produce a bulk glass composition. The cast bulk was then transferred to a stress relief furnace preheated to a stress relief temperature, held for 1 hour to remove stress, and then cooled to room temperature at a rate of 1°C / min. The cooled bulk was pulverized using a stamp mill and a jet mill to prepare powders of lead-free glass compositions G-1 to G-3.

[0079] (Measurement of characteristic temperatures of glass compositions G-1 to G-3) The characteristic temperatures of G-1 to G-3 were measured using the same differential thermal analyzer as in Experiment 1. The measurement conditions were as follows: α-alumina was used as the standard sample, the measurement atmosphere was nitrogen, and the heating rate was 5°C / min. The measurement results of the softening points Ts are also shown in Table 2.

[0080] [Table 2]

[0081] As shown in Table 2, it has been confirmed that glass compositions with desirable characteristic temperatures can be obtained by controlling the constituent components and contents of the glass. It has also been confirmed that the crystallization peak temperatures Tcp of G-1 to G-3 are each 45°C or more higher than Ts.

[0082] (Production of glass frits GF-1 to GF-9 and investigation of bulk properties) The powders G-1 to G-3 prepared above and a filler powder were mixed in the ratios shown in Table 3 below to prepare glass frits GF-1 to GF-9 that serve as the basis for the electrical insulating coating 2. As the filler powder, spherical SiO2 powder (average particle size 1 μm) was used.

[0083] Each of the prepared glass frits GF-1 to GF-9 was used to form a powder compact, which was then fired at a temperature 20°C higher than the Ts of the glass composition used to produce a bulk body corresponding to the electrical insulating coating 2. The bulk body was then ground into a prismatic shape (4 mm x 4 mm x 15 mm) to prepare a sample for measuring the linear expansion coefficient. The linear expansion coefficient of each measurement sample was measured using a thermal dilatometer (ULVAC, Model DL-9600). The temperature range for measuring the linear expansion coefficient was from 30°C to the Tg of the glass composition. The results are also shown in Table 3.

[0084] [Table 3]

[0085] As shown in Table 3, it is confirmed that the linear expansion coefficient of the electrical insulating coating 2 can be controlled by mixing a filler into the glass composition.

[0086] (Prepare glass paste GP-1 to GP-9) Glass pastes GP-1 to GP-9 for the soft magnetic composite wire 10 were prepared by mixing 100 parts by mass of each of the glass frits GF-1 to GF-9 prepared in Experiment 2 with 10 parts by mass of nitrocellulose as a resin binder and 20 parts by mass of α-terpineol as a solvent.

[0087] [Experiment 3] (Production of soft magnetic composite plates SMCP-1r to SMCP-4r as reference samples) The glass paste GP-8 prepared in Experiment 2 was applied to both surfaces of the soft magnetic materials SM-1 to SM-4 prepared in Experiment 1 to form soft magnetic composite plate precursors that served as intermediate materials. The soft magnetic composite plate precursors were then subjected to a predetermined heat treatment to form an electrical insulating coating 2, producing soft magnetic composite plates SMCP-1r to SMCP-4r that served as reference samples. The heat treatment pattern involved a drying process in which the material was heated to 170°C and held there for 30 minutes, followed by a firing process in which the material was heated to a temperature 20°C higher than the Ts of the glass composition used and held there for 30 minutes. The thickness of the electrical insulating coating 2 was controlled by controlling the thickness of the glass paste coating.

[0088] (Property investigation of soft magnetic composite plates SMCP-1r to 4r) For the fabricated SMCP-1r to 4r, the iron loss Pi was measured in the same way as in Experiment 1. -1.0 / 400 and iron loss Pi -1.0 / 10k In addition, the Pi in Table 1 was measured. -1.0 / 400 and Pi -1.0 / 10k The reduction rate (Pi reduction rate) was calculated from the measurement results.

[0089] Additionally, Pi -1.0 / 400 and Pi -1.0 / 10k After the measurement, the sample was cut and the Vickers hardness of the cross section of the soft magnetic material was measured using a nanoindentation tester (Elionix Co., Ltd., model ENT-1100a), and the amount of strain in the soft magnetic material was calculated. The results are shown in Table 4.

[0090] [Table 4]

[0091] As shown in Table 4 and Table 1, the soft magnetic composite material plates SMCP-1r to 4r, which are the reference samples, have a higher Pi than the soft magnetic materials SM-1 to SM-4. -1.0 / 400 and Pi -1.0 / 10k However, it can be seen that Pi of SMCP-1r to 4r has decreased. -1.0 / 10k The rate of decrease is Pi -1.0 / 400 It can be seen that this is small compared to the rate of decrease.

[0092] [Experiment 4] (Preparation of soft magnetic composite wire) The glass pastes GP-1 to GP-9 prepared in Experiment 2 were applied to both surfaces of the soft magnetic filaments SMF-1 to 4 prepared in Experiment 1 to form soft magnetic composite wire precursors as intermediate materials, and then the soft magnetic composite wire precursors were subjected to a predetermined heat treatment to form electrical insulating coatings 2, thereby preparing soft magnetic composite wires. The heat treatment pattern was the same as in Experiment 3, except that the drying process was omitted. The thickness of the electrical insulating coating 2 was controlled by controlling the thickness of the glass paste coating film, as in Experiment 3.

[0093] (Production of soft magnetic composite plates SMCP-1i to 20i of the present invention) The prepared soft magnetic composite wires were bundled and arranged into a plate shape (70 mm long, 70 mm wide). At this time, the soft magnetic composite wires were arranged so that their longitudinal directions were all aligned (parallel). After that, the plate-shaped sample was subjected to a specified heat treatment while being pressed to a thickness of 300 μm, causing the electrical insulating coating 2 to soften, flow, and harden again, resulting in an integrated molding. The heat treatment pattern was the same as in Experiment 3, except that the drying process was omitted.

[0094] Next, the integrally molded plate-shaped samples were cut parallel to the longitudinal direction of the arranged soft magnetic composite wires to produce soft magnetic composite material plates SMCP-1i to 20i of the present invention (length 70 mm, width 20 mm, thickness 300 μm, the longitudinal direction of the sample plate and the longitudinal direction of the soft magnetic composite wires were parallel).

[0095] (Property investigation of soft magnetic composite plates SMCP-1i to 20i) The properties of the fabricated SMCP-1i to 20i were investigated in the same manner as in Experiment 3. In the Pi measurement, the applied magnetic field was adjusted to be parallel to the longitudinal direction of the sample plate (the magnetization direction was parallel to the longitudinal direction of the soft magnetic composite wire). The results are shown in Table 5.

[0096] [Table 5]

[0097] As shown in Tables 5 and 4, the soft magnetic composite plates SMCP-1i to 20i of the present invention have Pi values ​​equal to or higher than those of the reference samples SMCP-1r to 4r. -1.0 / 400 The Pi decreases by a much larger rate than that of SMCP-1r~4r. -1.0 / 10k This is thought to be due to a combination of the reduction in hysteresis loss due to the application of tensile strain to the soft magnetic filaments and the reduction in eddy current loss due to filamentization (reduction in the eddy current area).

[0098] [Experiment 5] (Production of soft magnetic composite plates SMCP-1c to 4c as comparison samples) The plate-shaped sample (length 70 mm, width 70 mm) integrally molded in Experiment 4 was cut perpendicular to the longitudinal direction of the arranged soft magnetic composite wires to produce comparative soft magnetic composite material plates SMCP-1c to 4c (length 70 mm, width 20 mm, thickness 300 μm, the longitudinal direction of the sample plate was perpendicular to the longitudinal direction of the soft magnetic composite wires).

[0099] (Property investigation of soft magnetic composite plates SMCP-1c to 4c) The properties of the fabricated SMCP-1i to 20i were investigated in the same manner as in Experiment 3. In the Pi measurement, the applied magnetic field was adjusted to be parallel to the longitudinal direction of the sample plate (the magnetization direction was perpendicular to the longitudinal direction of the soft magnetic composite wire). The results are shown in Table 6.

[0100] [Table 6]

[0101] As shown in Tables 6 and 1, the soft magnetic composite material plates SMCP-1c to 4c used as comparative samples had a higher Pi value than the soft magnetic materials SM-1 to SM-4. -1.0 / 400 and Pi -1.0 / 10k It can be seen that Pi is increasing. -1.0 / 400 Decrease rate and Pi -1.0 / 10k Pi, not the rate of decrease -1.0 / 400 Growth rate and Pi -1.0 / 10k From this result, it can be said that in a soft magnetic composite plate, it is desirable to align the magnetization direction with the longitudinal direction of the soft magnetic composite wire (the longitudinal direction of the soft magnetic filaments).

[0102] The above-described embodiments and experiments have been described to aid in understanding the present invention, and the present invention is not limited to the specific configurations described. For example, it is possible to replace part of the configuration of the embodiments with configurations within the technical common sense of those skilled in the art, and it is also possible to add configurations within the technical common sense of those skilled in the art to the configuration of the embodiments. In other words, it is possible to delete, replace, or add part of the configurations of the embodiments and experiments in this specification without departing from the technical spirit of the invention. [Explanation of symbols]

[0103] 1...soft magnetic filament, 2...electrical insulating coating, 10...soft magnetic composite wire, 20...soft magnetic composite material plate, 30...iron core, 31...stator slot, 32...slit, 33...teeth, 34...teeth claw portion, 35...yoke portion, 40...stator, 41...stator coil, 42...segment conductor, 43...electrical insulating material.

Claims

1. A soft magnetic composite plate in which a soft magnetic material and an electrically insulating coating are combined, the soft magnetic material has a filament shape; the electrically insulating coating includes a lead-free glass composition and has a linear expansion coefficient that is at least 3 ppm / K smaller than the linear expansion coefficient of the soft magnetic material; A soft magnetic composite wire is formed by forming the electrically insulating coating on the surface of the soft magnetic material in a filament shape, The soft magnetic composite wires are integrated so that their longitudinal directions are aligned in the in-plane direction of the plate shape of the soft magnetic composite material plate. A soft magnetic composite plate characterized by:

2. 2. The soft magnetic composite plate according to claim 1, The thickness of the soft magnetic composite plate is 0.01 mm or more and 3 mm or less, The space factor of the soft magnetic material is 80% by volume or more, The average thickness of the electrical insulating coating is less than 10% of the diameter of a circle having an equivalent area of ​​the cross section of the filament shape. A soft magnetic composite plate characterized by:

3. 2. The soft magnetic composite plate according to claim 1, The glass composition has the following nominal components expressed as oxides: 40% to 70% by mass of V 2 O 5 and 10% by mass or more and 35% by mass or less of P 2 O 5 and V 2 O 5 and the aforementioned P 2 O 5 and the total of these is 50% by mass or more and 98% by mass or less, BaO, Sb 2 O 3 , WO 3 , ZnO, K 2 O, Fe 2 O 3 , TeO 2 , Ag 2 O, and Li 2 O in a total amount of 2% by mass or more and 50% by mass or less, The balance is unavoidable impurities, The softening point of the glass composition is 500°C or less. A soft magnetic composite plate characterized by:

4. 3. The soft magnetic composite plate according to claim 2, The glass composition has the following nominal components expressed as oxides: 40% to 70% by mass of V 2 O 5 and 10% by mass or more and 35% by mass or less of P 2 O 5 and V 2 O 5 and the aforementioned P 2 O 5 and the total of these is 50% by mass or more and 98% by mass or less, BaO, Sb 2 O 3 , WO 3 , ZnO, K 2 O, Fe 2 O 3 , TeO 2 , Ag 2 O, and Li 2 O in a total amount of 2% by mass or more and 50% by mass or less, The balance is unavoidable impurities, The softening point of the glass composition is 500°C or less. A soft magnetic composite plate characterized by:

5. 4. The soft magnetic composite plate according to claim 3, the electrically insulating coating comprises 75% by volume or less of a filler of oxide particles; The filler is SiO 2 , ZrO 2 , Al 2 O 3 , Nb 2 O 5 , ZrSiO 4 , Zr 2 (WO 4 )(PO 4 ) 2 , 2MgO·2Al 2 O 3 ・5SiO 2 , 3Al 2 O 3 ・2SiO 2 , and LiAlSiO 4 one or more of the group consisting of A soft magnetic composite plate characterized by:

6. 5. The soft magnetic composite plate according to claim 4, the electrically insulating coating comprises 75% by volume or less of a filler of oxide particles; The filler is SiO 2 , ZrO 2 , Al 2 O 3 , Nb 2 O 5 , ZrSiO 4 , Zr 2 (WO 4 )(PO 4 ) 2 , 2MgO·2Al 2 O 3 ・5SiO 2 , 3Al 2 O 3 ・2SiO 2 , and LiAlSiO 4 one or more of the group consisting of A soft magnetic composite plate characterized by:

7. 6. The soft magnetic composite plate according to claim 5, 10. A soft magnetic composite plate, wherein the coefficient of linear expansion of the electrical insulating coating is less than 10 ppm / °C.

8. 7. The soft magnetic composite plate according to claim 6, 10. A soft magnetic composite plate, wherein the coefficient of linear expansion of the electrical insulating coating is less than 10 ppm / °C.

9. The soft magnetic composite plate according to any one of claims 1 to 8, A soft magnetic composite plate, characterized in that the soft magnetic material has a tensile strain in the range of 10 μST to 1000 μST along its longitudinal direction.

10. The soft magnetic composite plate according to any one of claims 1 to 8, The soft magnetic composite plate is characterized in that a tensile strain occurs in the in-plane direction of the soft magnetic composite plate in the range of 10 μST to 1000 μST.

11. An iron core made of a laminate of soft magnetic composite plates, The soft magnetic composite plate is a soft magnetic composite plate according to any one of claims 1 to 8, The soft magnetic material is arranged so that the longitudinal direction of the wire-shaped soft magnetic material is parallel to the magnetization direction applied to the soft magnetic composite plate. An iron core characterized by:

12. An iron core made of a laminate of soft magnetic composite plates, The soft magnetic composite plate is the soft magnetic composite plate according to claim 9, The soft magnetic material is arranged so that the longitudinal direction of the wire-shaped soft magnetic material is parallel to the magnetization direction applied to the soft magnetic composite plate. An iron core characterized by:

13. An iron core made of a laminate of soft magnetic composite plates, The soft magnetic composite plate is the soft magnetic composite plate according to claim 10, The soft magnetic material is arranged so that the longitudinal direction of the wire-shaped soft magnetic material is parallel to the magnetization direction applied to the soft magnetic composite plate. An iron core characterized by:

14. A rotating electric machine having an iron core, A rotating electric machine, wherein the iron core is the iron core according to claim 11.

15. A rotating electric machine having an iron core, A rotating electric machine, wherein the iron core is the iron core according to claim 12.

16. A rotating electric machine having an iron core, A rotating electric machine, wherein the iron core is the iron core according to claim 13.

Images