Magnetic wedge and rotating electric machine

Abstract

To provide magnetic wedges and rotary electric machines with excellent magnetic and mechanical properties.SOLUTION: A magnetic wedge of the embodiment is a magnetic wedge of a rotary electric machine, the magnetic wedge comprises a plurality of flat magnetic metal particles and an intervening phase, and the proportion of flat magnetic metal particles occupying the surface of the magnetic wedge in the thickness direction is larger than the proportion occupying the center of the magnetic wedge in the thickness direction.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] An embodiment of the present invention relates to a magnetic wedge and a rotating electric machine. [Background technology]

[0002] Typically, the coil windings of a rotating electric machine are housed in core slots and supported and fixed by wedges installed at the slot openings. While non-magnetic materials are typically used for these wedges, discontinuities in the magnetic reluctance in the air gap between the stator core and rotor core result in pulsation in the magnetic flux distribution on the surface of the core facing the wedge across the air gap, resulting in increased harmonic loss. To reduce this harmonic loss, wedges with moderate magnetic properties (magnetic wedges) have long been used. The use of magnetic wedges reduces harmonic loss and improves the efficiency of rotating electric machines. Figure 1 is a schematic diagram illustrating the use and effects of a magnetic wedge. Figure 1 shows a radial gap-type rotating electric machine as an example. Figure 1 illustrates a magnetic wedge 100, a coil 230, core teeth 250, and core slots 260.

[0003] It goes without saying that the higher the magnetic permeability of a magnetic wedge, the more effectively it can reduce harmonic loss. However, as shown in Figure 1, magnetic wedges are arranged to bridge adjacent core teeth, which has the disadvantage of increasing leakage magnetic flux flowing between the core teeth through the magnetic wedge. Furthermore, existing magnetic wedges have low saturation magnetization, which makes them prone to magnetic saturation, and they also have low loss, limiting the extent to which they can improve the efficiency of rotating electric machines. Furthermore, existing magnetic wedges have low permeability, which limits the extent to which they can improve the efficiency of rotating electric machines, and they are insufficient in terms of thermal stability and mechanical properties (strength and toughness). Therefore, it is desirable to improve the properties of magnetic wedges in terms of saturation magnetization, permeability, loss, strength, toughness, etc. It is particularly desirable to improve the properties of magnetic wedges in terms of permeability, loss, strength, etc. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Utility Model Application Publication No. 58-6572 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a magnetic wedge and a rotating electric machine having excellent magnetic and mechanical properties. [Means for solving the problem]

[0006] The magnetic wedge of the embodiment includes: A radial gap type in which the stator is arranged facing the rotor at a predetermined radial distance. A magnetic wedge used in a rotating electric machine, the magnetic wedge comprising a plurality of flat magnetic metal particles and an intervening phase, wherein the flat magnetic metal particles occupy a larger proportion of the surface portion in the thickness direction of the magnetic wedge than the proportion of the central portion in the thickness direction of the magnetic wedge. Ku , The thickness direction is the radial direction, and the flat surfaces of the flat magnetic metal particles are oriented in at least one direction, the rotation direction and the axial direction of the rotating electric machine. . [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic diagram showing the use of a magnetic wedge and the effect of the magnetic wedge. [Figure 2] FIG. 3 is a conceptual diagram showing an example of how to determine the thickness of a flat magnetic metal particle in the magnetic wedge of the first embodiment. [Figure 3] 3 is a conceptual diagram for explaining how to determine the maximum length and minimum length within the flat surface of a flat magnetic metal particle in the magnetic wedge of the first embodiment. FIG. [Figure 4] FIG. 10 is a conceptual diagram for explaining another example of how to determine the maximum length and minimum length within the flat surface of a flat magnetic metal particle in the magnetic wedge of the first embodiment. [Figure 5] This is a schematic diagram showing the direction in which the coercive force was measured in the magnetic wedge of the first embodiment, changing the direction every 22.5 degrees relative to the 360-degree angle within the flat surface of the flat magnetic metal particle. [Figure 6] FIG. 2 is a schematic diagram of a flat magnetic metal particle in the magnetic wedge of the first embodiment. [Figure 7] FIG. 2 is a schematic diagram of a magnetic wedge according to the first embodiment. [Figure 8] FIG. 2 is a schematic diagram of a magnetic wedge according to the first embodiment. [Figure 9] FIG. 2 is a schematic diagram of a magnetic wedge according to the first embodiment. [Figure 10] FIG. 10 is a schematic diagram of a fifth step in the method for manufacturing the magnetic wedge according to the first embodiment. [Figure 11] FIG. 6 is a schematic diagram illustrating an example of a radial gap type rotating electric machine according to a second embodiment. [Figure 12] FIG. 6 is a schematic diagram illustrating an example of an axial gap type rotating electric machine according to a second embodiment. [Figure 13] FIG. 4 is a schematic diagram illustrating an example of a generator according to a second embodiment. [Figure 14] FIG. 6 is a schematic diagram illustrating an example of a linear motor according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments will be described with reference to the drawings. In the drawings, identical or similar parts are denoted by identical or similar reference numerals. In this specification, measurements are made at 25°C unless otherwise specified.

[0009] In this specification, the terms "axial direction," "rotational direction," and "radial direction" are defined relative to the rotor of the rotating electric machine. That is, "axial direction" refers to the direction along the rotational axis of the rotor, "rotational direction" refers to the direction around the rotational axis of the rotor (or the tangential direction thereof), and "radial direction" refers to the direction perpendicular to (perpendicular to) the rotational axis of the rotor.

[0010] (First embodiment) The magnetic wedge of the embodiment is a magnetic wedge for a rotating electric machine, and is a magnetic wedge that comprises a plurality of flat magnetic metal particles and an intervening phase, and in which the flat magnetic metal particles occupy a larger proportion of the surface portion in the thickness direction than the proportion of the central portion in the thickness direction of the magnetic wedge.

[0011] The magnetic wedge of the embodiment is a magnetic wedge for a radial gap type rotating electric machine in which a stator is arranged facing a rotor at a predetermined radial distance, and the thickness direction is the radial direction. The magnetic wedge of the embodiment is a magnetic wedge used in an axial gap type rotating electric machine in which a stator is arranged facing a rotor at a predetermined axial distance, and the thickness direction is the axial direction. The flat magnetic metal particles have an average thickness of 10 nm to 100 μm, flat surfaces, and a magnetic metal phase containing at least one first element selected from the group consisting of Fe, Co, and Ni, and the average ratio of the average length within the flat surfaces to the thickness is 5 to 10,000, and the intervening phase is present between the flat magnetic metal particles and contains at least one second element selected from the group consisting of oxygen (O), carbon (C), nitrogen (N), and fluorine (F).

[0012] The flat magnetic metal particles are flaky particles (flattened particles) that have a flaky shape (flattened shape).

[0013] The thickness refers to the average thickness of a single flat magnetic metal particle. Any method can be used to determine the thickness, as long as it can determine the average thickness of a single flat magnetic metal particle. For example, a cross section perpendicular to the flat surface of a flat magnetic metal particle can be observed using a transmission electron microscope (TEM), a scanning electron microscope (SEM), or an optical microscope. Ten or more randomly selected locations along the flat surface of the observed cross section of the flat magnetic metal particle can be selected, the thickness of each selected location can be measured, and the average value can be calculated. Alternatively, ten or more equally spaced locations along the flat surface of the observed cross section of the flat magnetic metal particle can be selected from one end to the other (it is preferable not to select the end and other ends because they are special locations), the thickness of each selected location can be measured, and the average value can be calculated. Figure 2 is a conceptual diagram showing an example of how to determine the thickness of a flat magnetic metal particle in the magnetic wedge of the first embodiment. Figure 2 specifically illustrates how to determine the thickness in this case. Ten points are selected at equal intervals from one end to the other in the direction of the flat surface (excluding the ends), and the thicknesses at each point are t1, t2, . . . , t 10 Then, the thickness of the flat magnetic metal particle is (t1 + t2 + + t 10 ) / 10. It is preferable to measure as many points as possible, as this allows for obtaining average information. If the cross-sectional contour line is very uneven or has a rough surface, making it difficult to determine the average thickness as is, it is preferable to smooth the contour line with an average straight line or curve, as appropriate, before carrying out the above method.

[0014] Furthermore, the average thickness refers to the average value of the thicknesses of multiple flat magnetic metal particles and is distinct from the simple "thickness" mentioned above. When determining the average thickness, it is preferable to use an average value for 20 or more flat magnetic metal particles. It is also preferable to determine the average thickness for as many flat magnetic metal particles as possible, as this allows for obtaining average information. Furthermore, if it is not possible to observe more than 20 flat magnetic metal particles, it is preferable to observe as many flat magnetic metal particles as possible and use an average value for them. The average thickness of the flat magnetic metal particles is preferably 10 nm to 100 μm. It is more preferably 10 nm to 1 μm, and even more preferably 10 nm to 100 nm. It is also preferable that the flat magnetic metal particles include those with a thickness of 10 nm to 100 μm, more preferably 10 nm to 1 μm, and even more preferably 10 nm to 100 nm. This is preferable because it allows for sufficiently small eddy current loss when a magnetic field is applied in a direction parallel to the flat surfaces. Furthermore, a smaller thickness is preferable because the magnetic moment is confined in a direction parallel to the flat surface, and magnetization easily progresses by rotational magnetization. When magnetization progresses by rotational magnetization, the magnetization tends to progress reversibly, so the coercive force becomes smaller, which is preferable because hysteresis loss can be reduced.

[0015] The average length of a flat magnetic metal particle is defined as (a + b) / 2, where a is the maximum length within the flat surface and b is the minimum length. The maximum length a and minimum length b can be calculated as follows. For example, consider the rectangle with the smallest area among the rectangles circumscribing the flat surface. The length of the long side of this rectangle is the maximum length a, and the length of the short side is the minimum length b. Figure 3 is a conceptual diagram illustrating how to calculate the maximum and minimum lengths within the flat surface of a flat magnetic metal particle in the magnetic wedge of the first embodiment. Figure 3 is a schematic diagram showing the maximum length a and minimum length b calculated using the above method for several flat magnetic metal particles as examples. Like the average thickness, the maximum length a and minimum length b can be calculated by observing the flat magnetic metal particles using a TEM, SEM, or optical microscope. It is also possible to calculate the maximum length a and minimum length b by performing image analysis of a micrograph on a computer. In either case, it is preferable to calculate the maximum length a and minimum length b for 20 or more flat magnetic metal particles. It is also preferable to calculate the maximum length a and minimum length b for as many flat magnetic metal particles as possible, as this allows for obtaining average information. Furthermore, if it is not possible to observe more than 20 flat magnetic metal particles, it is preferable to observe as many flat magnetic metal particles as possible and adopt the average value for them. Furthermore, since it is preferable to obtain an average value as much as possible, it is preferable to perform observation or image analysis in a state where the flat magnetic metal particles are uniformly dispersed (in a state where multiple flat magnetic metal particles with different maximum and minimum lengths are dispersed as randomly as possible). For example, it is preferable to thoroughly mix multiple flat magnetic metal particles and then attach them to tape, or to drop multiple flat magnetic metal particles from above and attach them to tape, and then perform observation or image analysis.

[0016] However, depending on the flat magnetic metal particle, determining the maximum length a and minimum length b using the above method may result in a calculation that does not capture the essence. Figure 4 is a conceptual diagram illustrating another example of how to determine the maximum and minimum lengths within the flat surface of a flat magnetic metal particle in the magnetic wedge of the first embodiment. For example, in the case shown in Figure 4, the flat magnetic metal particle is elongated and curved. In this case, the maximum and minimum lengths of the flat magnetic metal particle are essentially the lengths a and b shown in Figure 4. As such, the method of determining the maximum lengths a and b is not completely unique. Basically, it is acceptable to "consider the rectangle with the smallest area among the rectangles circumscribing the flat surface, and set the length of the long side of that rectangle as the maximum length a and the length of the short side of that rectangle as the minimum length b." However, depending on the shape of the particle, if this method does not capture the essence, the maximum length a and minimum length b can be calculated flexibly to capture the essence. The thickness t is defined as the length perpendicular to the flat surface. The ratio A of the average length in the flat plane to the thickness is defined as A=((a+b) / 2) / t, where a is the maximum length, b is the minimum length, and t is the thickness.

[0017] The average ratio of the average length within the flat surface to the thickness of the flat magnetic metal particles is preferably 5 or more and 10,000 or less, because this increases the magnetic permeability and also increases the ferromagnetic resonance frequency, thereby reducing ferromagnetic resonance loss.

[0018] The ratio of the average length within the flat surface to the thickness is the average value. Preferably, the average value for 20 or more flat magnetic metal particles is used. It is also preferable to measure as many flat magnetic metal particles as possible, as this allows for obtaining average information. If it is not possible to observe 20 or more flat magnetic metal particles, it is preferable to observe as many flat magnetic metal particles as possible and use the average value for them. For example, if there are particles Pa, Pb, and Pc, each with thicknesses Ta, Tb, and Tc, and average lengths within the flat surface La, Lb, and Lc, the average thickness is calculated as (Ta + Tb + Tc) / 3, and the average ratio of the average length within the flat surface to the thickness is calculated as (La / Ta + Lb / Tb + Lc / Tc) / 3.

[0019] The flat magnetic metal particles preferably have a coercive force difference depending on the direction within the flat surface. The larger the directional coercive force difference, the better, and it is preferably 1% or more. More preferably, the coercive force difference is 10% or more, even more preferably 50% or more, and even more preferably 100% or more. The coercive force difference ratio here is defined as (Hc(max)-Hc(min)) / Hc(min)×100(%), where Hc(max) is the maximum coercive force and Hc(min) is the minimum coercive force within the flat surface. Note that coercive force can be evaluated using a vibrating sample magnetometer (VSM) or the like. When the coercive force is low, a coercive force of 0.1 Oe or less can be measured by using a low magnetic field unit. Measurements are performed by changing the direction within the flat surface relative to the direction of the measurement magnetic field.

[0020] The phrase "having a coercive force difference" refers to the existence of a direction in which the coercive force is maximized and a direction in which the coercive force is minimized when a magnetic field is applied in a 360-degree direction within the flat surface and the coercive force is measured. For example, when the coercive force is measured by changing the direction every 22.5 degrees relative to a 360-degree angle within the flat surface, a coercive force difference is observed, i.e., there are angles where the coercive force is greater and angles where the coercive force is smaller. This is considered to be a "coercive force difference." Figure 5 is a schematic diagram showing the directions in which the coercive force is measured by changing the direction every 22.5 degrees relative to a 360-degree angle within the flat surface of a flat magnetic metal particle in the magnetic wedge of the first embodiment. Note that Figure 5 illustrates the flat surface of the flat magnetic metal particle as viewed from above. Having a coercive force difference within the flat surface is preferable because it reduces the minimum coercive force value compared to an isotropic case in which there is almost no coercive force difference. In materials with magnetic anisotropy within the flat plane, the coercive force varies depending on the direction within the flat plane, and the minimum coercive force value is smaller than that of magnetically isotropic materials. This reduces hysteresis loss and improves magnetic permeability, which is preferable. Figure 5 shows a flat magnetic metal particle 10 and a flat plane 6.

[0021] The flat magnetic metal particles also have a magnetic metal phase containing at least one first element selected from the group consisting of Fe, Co, and Ni. The flat magnetic metal particles contain Fe and Co, and the amount of Co is preferably 10 atomic % to 60 atomic % of the total amount of Fe and Co, and more preferably 10 atomic % to 40 atomic %. This is preferable because it makes it easier to impart a moderately large magnetic anisotropy and improves the above-mentioned magnetic properties. Fe-Co systems are also preferable because they easily achieve high saturation magnetization. Furthermore, by having the composition range of Fe and Co fall within the above range, it is preferable to achieve higher saturation magnetization. It is also preferable for the flat magnetic metal particles and the attached metal to have the same composition, as this makes it easier to improve mechanical properties such as thermal stability, strength, and hardness. The elements can be easily analyzed by EDX (Energy Dispersive X-ray spectroscopy) or ICP (Inductively Coupled Plasma) optical emission spectroscopy.

[0022] The flat magnetic metal particles preferably contain at least one non-magnetic metal selected from the group consisting of Mg, Al, Si, Ca, Zr, Ti, Hf, Zn, Mn, Ba, Sr, Cr, Mo, Ag, Ga, Sc, V, Y, Nb, Pb, Cu, In, Sn, and rare earth elements. This improves the thermal stability and oxidation resistance of the flat magnetic metal particles. Among these, Al and Si are particularly preferred because they easily dissolve in Fe, Co, and Ni, the main components of the flat magnetic metal particles, and contribute to improving thermal stability and oxidation resistance.

[0023] In order to induce magnetic anisotropy, one method is to make the crystallinity of the flat magnetic metal particles as amorphous as possible and then induce magnetic anisotropy in one direction in the plane using a magnetic field or strain. In this case, it is desirable to use a composition that makes it as easy to make the flat magnetic metal particles amorphous as possible. From this perspective, it is preferable that the magnetic metal contained in the flat magnetic metal particles contains at least one additive element selected from B (boron), Si (silicon), Al (aluminum), C (carbon), Ti (titanium), Zr (zirconium), Hf (hafnium), Nb (niobium), Ta (tantalum), Mo (molybdenum), Cr (chromium), Cu (copper), W (tungsten), P (phosphorus), N (nitrogen), Ga (gallium), and Y (yttrium). It is preferable that the additive element has a large difference in atomic radius from at least one first element selected from the group consisting of Fe, Co, and Ni. Furthermore, the additive element is preferably at least one first element selected from the group consisting of Fe, Co, and Ni, such that the mixing enthalpy of the additive element becomes negative. Furthermore, a multi-element system consisting of three or more elements, including the first element and the additive element, is preferable. Furthermore, semimetallic additive elements such as B and Si have a slow crystallization rate and are prone to amorphization, making them advantageous to incorporate into the system. From the above perspectives, B, Si, P, Ti, Zr, Hf, Nb, Y, Cu, etc. are preferable, and it is more preferable that the additive element includes one of B, Si, Zr, Hf, and Y. For example, it is preferable that the first element of the magnetic metal phase includes Fe and Co, and the additive element includes Si and B. Furthermore, it is preferable that the total amount of the additive element is 0.001 at% to 80 at% of the total amount of the first element and the additive element. More preferably, it is 5 at% to 80 at% and even more preferably, it is 10 at% to 40 at%. The larger the total amount of the added elements, the more the amorphization progresses and the easier it is to impart magnetic anisotropy, which is preferable (i.e., it is preferable from the viewpoint of low loss and high magnetic permeability), but on the other hand, it is not preferable in that the proportion of the magnetic metal phase decreases, which reduces the saturation magnetization. For these reasons, it is important to select the composition and the amount of added elements by comprehensively considering high saturation magnetization, low loss, high magnetic permeability, etc.

[0024] It is preferable that at least a portion of the surface of the flat magnetic metal particles is covered with a coating layer having a thickness of 0.1 nm or more and 1 μm or less and containing at least one second element selected from the group consisting of oxygen (O), carbon (C), nitrogen (N) and fluorine (F).

[0025] 6 is a schematic diagram of a flat magnetic metal particle in the magnetic wedge of the first embodiment, showing a coating layer 9 and a flat magnetic metal particle 10.

[0026] The coating layer preferably contains at least one non-magnetic metal selected from the group consisting of Mg, Al, Si, Ca, Zr, Ti, Hf, Zn, Mn, Ba, Sr, Cr, Mo, Ag, Ga, Sc, V, Y, Nb, Pb, Cu, In, Sn, and rare earth elements, and at least one second element selected from the group consisting of oxygen (O), carbon (C), nitrogen (N), and fluorine (F). From the viewpoint of thermal stability, Al and Si are particularly preferred as non-magnetic metals. When the flat magnetic metal particles contain at least one non-magnetic metal selected from the group consisting of Mg, Al, Si, Ca, Zr, Ti, Hf, Zn, Mn, Ba, Sr, Cr, Mo, Ag, Ga, Sc, V, Y, Nb, Pb, Cu, In, Sn, and rare earth elements, the coating layer preferably contains at least one non-magnetic metal that is the same as the non-magnetic metal that is one of the components of the flat magnetic metal particles. Among oxygen (O), carbon (C), nitrogen (N), and fluorine (F), it is preferable to contain oxygen (O), and it is preferable to use an oxide or a composite oxide. The above is from the viewpoint of ease of coating layer formation, oxidation resistance, and thermal stability. This improves the adhesion between the flat magnetic metal particles and the coating layer, making it possible to improve the thermal stability and oxidation resistance of the magnetic wedge described below. The coating layer not only improves the thermal stability and oxidation resistance of the flat magnetic metal particles, but also improves the electrical resistance of the flat magnetic metal particles. Increasing the electrical resistance suppresses eddy current loss and improves the frequency characteristics of magnetic permeability. For this reason, it is preferable for the coating layer to have high electrical resistance, for example, a resistance value of 1 mΩ·cm or more.

[0027] The presence of a coating layer is also preferable from a magnetic standpoint. Because the thickness of flat magnetic metal particles is small compared to the size of the flat surfaces, they can be considered as a pseudo-thin film. In this case, the coating layer formed on the surface of the flat magnetic metal particles and integrated can be considered as a pseudo-laminated thin film structure, and the magnetic domain structure is energetically stabilized. This makes it possible to reduce the coercive force (thereby reducing hysteresis loss), which is preferable. At this time, the magnetic permeability also increases, which is preferable. From this standpoint, it is more preferable that the coating layer is non-magnetic (this makes it easier to stabilize the magnetic domain structure).

[0028] The thicker the coating layer, the better from the standpoints of thermal stability, oxidation resistance, and electrical resistance. However, if the coating layer is too thick, the saturation magnetization decreases, which also reduces the magnetic permeability, which is undesirable. Also, from a magnetic standpoint, if the thickness is too thick, the "effect of stabilizing the magnetic domain structure to achieve low coercivity, low loss, and high magnetic permeability" is reduced. Taking these factors into consideration, the preferred coating layer thickness is between 0.1 nm and 1 μm, and more preferably between 0.1 nm and 100 μm.

[0029] FIG. 7 is a schematic diagram of a magnetic wedge according to this embodiment. Magnetic wedges are not limited to simple rectangular parallelepiped shapes, as shown in FIG. 7, but may also have various cross-sectional shapes, such as trapezoidal, hexagonal, or convex. Regardless of the shape, the three axial directions that intersect perpendicularly or orthogonally are defined as the width direction, thickness direction, and longitudinal direction. For example, the longitudinal direction of a magnetic wedge is the direction in which the length of the magnetic wedge is longer. The thickness direction and width direction of a magnetic wedge are directions perpendicular to the longitudinal direction of the magnetic wedge. Furthermore, the thickness direction and width direction of a magnetic wedge can be distinguished from the orientation state of the flat magnetic metal particles, which will be described later.

[0030] FIG. 8 is a schematic diagram of a magnetic wedge according to this embodiment. The magnetic wedge is a magnetic wedge for a radial gap type rotating electric machine in which a stator is disposed facing a rotor at a predetermined radial distance, and the flat surfaces are oriented in at least one of the rotational direction and the axial direction. Since it is sufficient that the flat surfaces are oriented, the magnetic metal particles may be arranged so as to be dispersed when the magnetic wedge is observed in a cross section consisting of the longitudinal and width directions. Furthermore, it is preferable that the magnetic metal particles are arranged so as to form layers with adjacent magnetic metal particles in the rotational or axial direction when the magnetic wedge is observed in a cross section consisting of the longitudinal and width directions. More preferably, the flat surfaces are oriented in both the rotational and axial directions. In the case of a magnetic wedge for a radial gap type rotating electric machine, the longitudinal direction of the magnetic wedge is the axial direction of the rotating electric machine, the width direction of the magnetic wedge is the rotational direction of the rotating electric machine, and the thickness direction of the magnetic wedge is the radial direction of the rotating electric machine. In this case, the orientation angle of the flat surface relative to the rotation direction is 45 degrees or less, preferably 1 degree or more and 45 degrees or less, preferably 1 degree or more and 30 degrees or less, more preferably 1 degree or more and 20 degrees or less, and even more preferably 1 degree or more and 10 degrees or less. The orientation angle of the flat magnetic metal particles is calculated as follows. First, if the target magnetic wedge is installed inside a rotating electric machine, the target magnetic wedge is removed from the inside of the rotating electric machine. Here, the rotation direction of the rotating electric machine becomes the width direction of the target magnetic wedge. Next, the outer dimensions of the target magnetic wedge are measured. This determines the longitudinal direction of the magnetic wedge (the direction in which the magnetic wedge is longest). For example, if the target magnetic wedge has a roughly rectangular parallelepiped shape, the direction along the longest side of the roughly rectangular parallelepiped shape is determined as the longitudinal direction of the target magnetic wedge. Next, a cross section perpendicular to the longitudinal direction of the target magnetic wedge is determined. For such a cross section, the end faces of the target magnetic wedge are not used. For such a cross section, the target magnetic wedge is cut perpendicular to the longitudinal direction of the target magnetic wedge so that the length of the cross section is at least one-tenth of the longitudinal length of the target magnetic wedge. The cross section formed by cutting is a cross section including the width direction and thickness direction or a cross section perpendicular to the longitudinal direction. Next, the center of the cross section formed by cutting is determined. For example, the geometric center of the cross section is used as the center of the cross section formed by cutting. Next, the cross section formed by cutting of the target magnetic wedge is observed using an optical microscope, SEM, or TEM. Next, for each flat magnetic metal particle observed in the cross section formed by cutting, consider the rectangle with the smallest area among the rectangles circumscribing each flat magnetic metal particle, and define the angle between the long side direction of that rectangle and the rotation direction of the rotating electric machine in which the target magnetic wedge is installed as the orientation angle of that flat magnetic metal particle. Note that the orientation angle is the angle between the rotation direction and the flat surface of the flat magnetic metal particle, and is not distinguished as positive or negative. Even if a flat magnetic metal particle is not completely contained within the observation range (it is evaluated even if it protrudes from the region), the orientation angle of that particle is evaluated. However, among the flat magnetic metal particles, there may be particles whose particle outlines are unclear during observation, making them difficult to evaluate. In other words, there are cases where the particle outline cannot be clearly identified through image analysis, and in such cases, the particle is excluded from the observation target. In this way, the orientation angles of all flat magnetic metal particles contained within the observation range are determined, and the average value is used as the orientation angle. In addition, the cross sections to be observed are evaluated at multiple cross sections, for example, three or more cross sections, and the average value is used. Furthermore, it is preferable that the proportion of the flat magnetic metal particles in the radial surface portion is greater than the proportion of the flat magnetic metal particles in the radial center portion. More preferably, the ratio of the proportion of the flat magnetic metal particles in the radial surface portion to the proportion of the flat magnetic metal particles in the radial center portion is greater than 1, more preferably greater than 1 but less than 2, even more preferably 1.1 or greater but less than 2, and even more preferably 1.2 or greater but less than 2. A ratio greater than 2 results in poor structural balance between the surface and center, which is undesirable in terms of strength, etc. Here, the radial center portion refers to the region in the radial center of the magnetic wedge, extending from the radial center to the "average length of the flat magnetic metal particles." The radial surface portion refers to the region extending from the radial end to the "average length of the flat magnetic metal particles." An intermediate portion is provided between the surface portion and the center portion. The proportion of flat magnetic metal particles refers to the packing density of flat magnetic metal particles per cross-sectional area observed using an optical microscope, SEM, TEM, etc. The proportion of flat magnetic metal particles is expressed as the ratio (area proportion) of the sum (SAm) of all the areas (Am) of individual flat magnetic metal particles in the observed region of the center and surface area of ​​the cross section including the width and thickness directions of the magnetic wedge to the area (At) of the observed region (SAm / At). Furthermore, at least three or more cross sections are observed and evaluated, and the average value is used as the proportion of magnetic metal particles in the center and surface area of ​​the magnetic wedge. The area of ​​each flat particle is calculated using image processing software such as ImageJ. The area of ​​the entire observation region is also calculated using image processing software such as ImageJ. Thus, when the ratio of the flat magnetic metal particles in the radial surface portion to the flat magnetic metal particles in the radial center portion is greater than 1 and less than 2, the progress of thermal decomposition from the material surface can be suppressed, achieving higher heat resistance than when the flat magnetic metal particles are uniformly distributed. Furthermore, the presence of many flat magnetic metal particles on the surface suppresses the progression of cracks, achieving superior mechanical strength, such as higher strength, than when the flat magnetic metal particles are uniformly distributed. Furthermore, concentrating the flat magnetic metal particles in the surface portion increases the magnetic permeability in the surface portion, which is preferable because it increases the overall effective magnetic permeability. This is preferable because it improves the efficiency of the rotating electric machine. The ratio of the flat magnetic metal particles in the radial surface portion to the radial center portion is preferably 1.1 or more and 2 or less, and even more preferably 1.2 or more and 2 or less, thereby further improving the above-mentioned high heat resistance, high strength, and overall effective magnetic permeability. In FIG. 8, flat magnetic metal particles 10, intervening phases 20, and magnetic wedges 100 are shown. If the magnetic wedge in question is not installed inside a rotating electric machine, the longitudinal direction of the magnetic wedge is first determined. Next, the thickness direction is tentatively determined in a plane perpendicular to the longitudinal direction. Next, the center is determined with respect to the tentatively determined thickness direction, and the orientation angle of the flat magnetic metal particles at the center is determined. At this time, the orientation angle is defined as the smallest rectangle among the rectangles circumscribing the magnetic metal particles, and the long side direction of that rectangle forms with the "direction perpendicular to the tentatively determined thickness direction." Next, the orientation angle at the center is determined using the same procedure while changing the thickness direction in a cross section perpendicular to the longitudinal direction. At this time, the thickness direction is changed to achieve a realistic arrangement, assuming that the magnetic wedge will be installed inside a rotating electric machine. After that, the "tentative thickness direction" with the smallest orientation angle at the center is determined as the "official thickness direction."

[0031] FIG. 9 is a schematic diagram of a magnetic wedge for an axial gap type rotating electric machine. The magnetic wedge is used in an axial gap type rotating electric machine in which a stator is arranged facing a rotor at a predetermined axial distance, and the flat surfaces are oriented in at least one of the radial direction and the rotation direction. More preferably, the flat surfaces are oriented in both the radial direction and the rotation direction. In the case of a magnetic wedge used in an axial gap type rotating electric machine, the longitudinal direction of the magnetic wedge is the radial direction of the rotating electric machine, the width direction of the magnetic wedge is the rotation direction of the rotating electric machine, and the thickness direction of the magnetic wedge is the axial direction of the rotating electric machine. In this case, the orientation angle is 45 degrees or less, preferably 1 degree to 45 degrees, preferably 1 degree to 30 degrees, more preferably 1 degree to 20 degrees, and even more preferably 1 degree to 10 degrees. The orientation angle is the angle between the rotation direction and the flat surfaces of the flat magnetic metal particles, and there is no distinction between positive and negative. Furthermore, it is preferable that the proportion of the flat magnetic metal particles in the axial surface portion is greater than the proportion of the flat magnetic metal particles in the axial center portion. More preferably, the ratio of the proportion of the flat magnetic metal particles in the axial surface portion to the proportion of the flat magnetic metal particles in the axial center portion is greater than 1 and less than 2, more preferably 1.1 to 2, and even more preferably 1.2 to 2. The excellent mechanical properties, excellent magnetic properties, and improved efficiency of the rotating electric machine obtained are the same as in the radial gap type rotating electric machine described above, so they will not be described here. Figure 9 shows a magnetic wedge 100.

[0032] A method for manufacturing the magnetic wedge of this embodiment will be described below. Note that the manufacturing method is not particularly limited and will be described only as an example.

[0033] The first step is to produce a magnetic metal ribbon containing at least one first element selected from the group consisting of Fe, Co, and Ni. This step involves producing a ribbon or thin film using a film-forming device such as a roll quenching device or a sputtering device. In this case, when using a film-forming device, it is desirable to form a film with uniaxial anisotropy in the film plane by magnetic field deposition or rotational deposition. When using a film-forming device, it is possible to achieve a thin film, and the structure tends to be refined, making it easier to induce rotational magnetization. Therefore, when producing a material with rotational magnetization, it is desirable to use a film-forming method. A roll quenching device is suitable for mass synthesis and is therefore desirable when synthesizing bulk materials. A single-roll quenching device is simple and preferred.

[0034] The second step is heat-treating the magnetic metal ribbon at a temperature between 50°C and 800°C. In this step, the ribbon may be cut to an appropriate size to facilitate placement in an electric furnace for heat treatment. For example, cutting to an appropriate size may be performed using a mixer or similar device. This step is desirable because it facilitates improved pulverization in the subsequent third step, the crushing step. The heat treatment atmosphere is preferably a low-oxygen vacuum atmosphere, an inert atmosphere, or a reducing atmosphere, and more preferably a reducing atmosphere such as H2 (hydrogen), CO (carbon monoxide), or CH4 (methane). This is because even if the magnetic metal ribbon is oxidized, heat treatment in a reducing atmosphere can reduce the oxidized metal and return it to its original metal state. This also allows for the reduction of a magnetic metal ribbon that has been oxidized and has lost its saturation magnetization, restoring it to its original state. Furthermore, if the crystallization of the magnetic metal ribbon progresses significantly due to heat treatment, the properties will deteriorate (coercive force increases, magnetic permeability decreases), so it is preferable to select conditions to suppress excessive crystallization. Furthermore, it is more preferable to perform the heat treatment in a magnetic field. The stronger the applied magnetic field, the better, but it is preferable to apply a magnetic field of 1 kOe or more, and even more preferably 10 kOe or more. This is preferable because it allows magnetic anisotropy to be expressed in the plane of the magnetic metal ribbon, achieving excellent magnetic properties.

[0035] The third step is to pulverize the heat-treated magnetic metal ribbon to produce flat magnetic metal particles. Prior to this pulverization, the magnetic metal ribbon or thin film may be cut to an appropriate size using a mixer or other device. In this step, pulverization is performed using a pulverizer such as a bead mill or planetary mill. Any type of pulverizer is acceptable. Examples include planetary mills, bead mills, rotary ball mills, vibrating ball mills, stirring ball mills (attritors), jet mills, centrifuges, and a combination of mills and centrifugation. During pulverization, cooling at a temperature below 0°C is preferred to facilitate pulverization. Cooling to liquid nitrogen temperature (77 K) or dry ice temperature (194 K) is particularly desirable, with liquid nitrogen temperature being even more desirable. This facilitates low-temperature embrittlement of the magnetic metal ribbon, facilitating pulverization. This method is preferred because it allows for efficient pulverization without applying excessive stress or strain to the magnetic metal ribbon. However, in many cases, the powder can be sufficiently pulverized without cooling, and in such cases, cooling is not necessary.

[0036] In the third step, the thickness of the flat magnetic metal particles can be reduced by combining rolling with simple pulverization. If the desired thickness is achieved by the second step, the rolling step can be omitted. Rolling can be performed simultaneously, or after pulverization, or after rolling. In this case, a device capable of applying strong gravitational acceleration is preferred, such as a planetary mill, bead mill, rotary ball mill, vibrating ball mill, stirring ball mill (attritor), jet mill, centrifuge, or a combination of milling and centrifugation. For example, a high-power planetary mill is preferred because it can easily apply gravitational accelerations of several tens of g. In the case of a high-power planetary mill, an inclined planetary mill is more preferred, in which the direction of the rotational gravitational acceleration and the direction of the revolutionary gravitational acceleration are not collinear but are angled. In a normal planetary mill, the direction of the gravitational acceleration due to rotation and the direction of the gravitational acceleration due to revolution are on the same line, but in an inclined planetary mill, the container rotates while tilted, so the direction of the gravitational acceleration due to rotation and the direction of the gravitational acceleration due to revolution are not on the same line but at an angle. This is preferable because it allows power to be transmitted to the sample efficiently, allowing for efficient milling and rolling. Furthermore, when considering mass production, a bead mill is preferable as it is easy to process large quantities.

[0037] It is desirable to carry out the above cutting, crushing and rolling (rolling is carried out as necessary, and not carried out if not necessary), and in some cases to repeat the cutting, crushing and rolling to process into flat magnetic metal particles of a predetermined thickness and aspect ratio. In this case, crushing and rolling is carried out so that the thickness is 10 nm to 100 μm, more preferably 10 nm to 1 μm, and even more preferably 10 nm to 100 nm, which results in particles that are prone to rotational magnetization, and is therefore preferable. In order to achieve the degree of orientation of the flat magnetic metal particles as in this embodiment, it is effective to improve the slippage of the flat magnetic metal particles and increase their fluidity, but for this purpose, the average thickness of the flat magnetic metal particles should be 10 μm to 30 μm. belowThe average ratio of the average length to the thickness of the flat magnetic metal particles is preferably 10 to 100, more preferably 10 to 50.

[0038] It is also desirable to appropriately remove lattice distortion from the obtained flat magnetic metal particles by heat treatment. This heat treatment, like the second step, is preferably carried out at a temperature of 50°C or higher and 800°C or lower, and the heat treatment atmosphere is preferably a vacuum atmosphere with a low oxygen concentration, an inert atmosphere, or a reducing atmosphere, and more preferably a reducing atmosphere such as H2, CO2, or CH4. It is even more desirable to carry out the heat treatment in a magnetic field. The reasons and details for these are the same as those for the second step, so a detailed explanation will be omitted here.

[0039] Next, in the fourth step, the above-mentioned interstitial phase and magnetic metal particles are mixed to form a mixed powder of the interstitial phase and flat magnetic metal particles. Next, in the fifth step, the mixed powder of the interstitial phase and magnetic metal particles is molded. Heat treatment may also be performed before or after the above steps as appropriate. In other words, heat treatment may be performed before or after molding, or simultaneously with molding. Heat treatment may also be performed before or after processing. The heat treatment conditions are as described above. It is more preferable to perform heat treatment in a magnetic field. The reasons and details for these are the same as those for the second step, so explanation will be omitted here.

[0040] In order to obtain the magnetic wedge of this embodiment, this fifth step is extremely important. In this step, it is preferable to use a method in which a press pressure is applied in one axial direction, such as uniaxial press molding or hot press molding. Figure 10 shows a schematic diagram of the fifth step in the method for manufacturing the magnetic wedge of this embodiment. When a press pressure is applied in one axial direction, the flat magnetic metal particles tend to be stacked and oriented in the direction of the press pressure application. However, simple uniaxial press molding results in a structure in which the flat magnetic metal particles are uniformly stacked and oriented, and the magnetic wedge of this embodiment cannot be obtained. Therefore, when applying a press pressure in the uniaxial direction, the molding die is magnetized in a direction intersecting the direction of the press pressure application. In other words, it is preferable that the die be magnetized in a direction perpendicular to the direction of the press pressure application. Generally, the distance (gap) between the mold die and the mold punch is very narrow, for example, about 5 μm. In this case, the flat magnetic metal particles have difficulty moving inside the mold, and the structure of this embodiment cannot be obtained. Therefore, the distance between the mold die and the mold punch is appropriately adjusted. For example, in the case of flat magnetic metal particles with an average thickness of 10 to 20 μm and an average ratio of the average length within the flat surface to the thickness of about 10 to 50, a gap of about 50 μm is provided. By providing such a gap, the fluidity of the intervening phase is increased, and it flows out appropriately through the gap, expelling the voids contained in the magnetic material. Furthermore, at this time, the flat magnetic metal particles are oriented while moving inside the mold, and are attracted to the magnetized mold punch, causing local segregation. On the other hand, if the gap between the hot press die and punch is too large, the interstitial phase will overflow, resulting in a reduced amount of interstitial phase in the magnetic material, which is undesirable. Therefore, it is important to appropriately set the distance (gap) between the die and punch. For flat magnetic metal particles with an average thickness of 10 to 20 μm and an average ratio of the average length within the flat surface to the thickness of approximately 10 to 50, the gap is preferably greater than 5 and less than 100 μm, and more preferably between 10 and 80 μm (around 50 μm is more preferable). However, the optimal gap range may change depending on the size of the flat magnetic metal particles (average thickness, average ratio of the average length within the flat surface to the thickness). Furthermore, the optimal gap range may also change depending on the type of interstitial phase and molding conditions such as temperature, pressure, and time. Therefore, this is merely a guideline, and it is important to appropriately set the gap depending on the actual size of the flat magnetic metal particles, the type of interstitial phase, and molding conditions such as temperature, pressure, and time. Furthermore, to realize the structure of this embodiment, a magnetic field is applied in a direction perpendicular to the direction of application of the pressing pressure. As a result, a structure is obtained in which flat magnetic metal particles are more distributed in the surface portion of the formed magnetic wedge than in the center portion. At least one of "using a mold magnetized in a direction perpendicular to the direction of application of the pressing pressure" and "applying a magnetic field in a direction perpendicular to the direction of application of the pressing pressure" is essential, and it is more preferable to perform both. Furthermore, to achieve such orientation, it is more preferable to perform hot press molding while applying a magnetic field. In other words, it is preferable to mold while simultaneously applying heat, a magnetic field, and pressing pressure. As a result of the above, the structure of this embodiment can be more effectively realized.

[0041] When measuring the coercive force depending on the direction within the plane of the magnetic wedge (within a plane parallel to the flat surface of the flat magnetic metal particle), for example, the coercive force is measured by changing the direction every 22.5 degrees relative to a 360-degree angle within the plane.

[0042] By having a coercive force difference within the plane of the magnetic wedge, the minimum coercive force value becomes smaller than in the case of an isotropic material with almost no coercive force difference, which is preferable. In a material with magnetic anisotropy within the plane, the coercive force varies depending on the direction within the plane, and the minimum coercive force value becomes smaller than in a magnetically isotropic material. This is preferable because it reduces hysteresis loss and improves magnetic permeability.

[0043] Within the plane of the magnetic wedge (within a plane parallel to the flat surface of the flat magnetic metal particle), the larger the percentage of coercive force difference due to direction, the better, and it is preferably 1% or more. More preferably, the percentage of coercive force difference is 10% or more, even more preferably, the percentage of coercive force difference is 50% or more, and even more preferably, the percentage of coercive force difference is 100% or more. The percentage of coercive force difference here is defined as (Hc(max)-Hc(min)) / Hc(min)×100(%), where Hc(max) is the maximum coercive force and Hc(min) is the minimum coercive force within the flat surface.

[0044] The coercive force can be easily evaluated using a vibrating sample magnetometer (VSM) or the like. When the coercive force is low, a coercive force of 0.1 Oe or less can be measured by using a low magnetic field unit. Measurements are performed by changing the direction of the measuring magnetic field within the plane of the magnetic wedge (within a plane parallel to the flat surface of the flat magnetic metal particle).

[0045] When calculating the coercive force, the difference between the magnetic fields at the two points where the horizontal axis intersects (magnetic fields H1 and H2 where magnetization becomes zero) can be divided by 2 (i.e., coercive force = |H2-H1| / 2).

[0046] The intervening phase contains at least one second element selected from the group consisting of oxygen (O), carbon (C), nitrogen (N), and fluorine (F). This is because it can increase the resistance. The electrical resistivity of the intervening phase is preferably higher than that of the flat magnetic metal particles. This is because it can reduce the eddy current loss of the flat magnetic metal particles. The intervening phase surrounds the flat magnetic metal particles, which is preferable because it can improve the oxidation resistance and thermal stability of the flat magnetic metal particles. Among these, those containing oxygen are more preferable from the viewpoint of high oxidation resistance and high thermal stability. The intervening phase also plays a role in mechanically bonding the flat magnetic metal particles together, which is also preferable from the viewpoint of high strength.

[0047] The intervening phase preferably contains a resin. Examples of resins that can be used include thermoplastic resins, thermosetting resins, polyester resins, vinyl ester resins, polyethylene resins, polystyrene resins, polyvinyl chloride resins, polyvinyl butyral resins, polyvinyl alcohol resins, polybutadiene resins, Teflon® resins, polyurethane resins, cellulose resins, ABS resins, nitrile-butadiene rubbers, styrene-butadiene rubbers, silicone resins, other synthetic rubbers, natural rubbers, epoxy resins, phenolic resins, allyl resins, polybenzimidazole resins, amide resins, polyimide resins, polyamideimide resins, bismaleimide resins, and copolymers thereof. To achieve high thermal stability, it is particularly preferable to use a silicone resin, polyimide resin, or imide resin, which has high heat resistance. Epoxy resins, phenolic resins, and polyester resins are generally used resins that offer relatively high heat resistance and strength, and are therefore preferred. In addition, to increase strength, materials such as FRP (Fiber-Reinforced Plastics) containing fibers such as glass fiber, aramid fiber (Kevlar fiber), carbon fiber, Zylon fiber, polyethylene fiber (Dyneema), and boron fiber are also preferred. This strengthens the bond between the flat magnetic metal particles and the intervening phase, which tends to improve mechanical properties such as thermal stability, strength, and toughness. Furthermore, since the intervening phase surrounds the flat magnetic particles, the particles have excellent oxidation resistance and are less likely to suffer from deterioration of magnetic properties due to oxidation of the flat magnetic metal particles, which is also preferred. The type of resin can be identified using infrared spectroscopy (IR), nuclear magnetic resonance (NMR), and other methods.

[0048] The molecular weight of the intervening phase is preferably 100 or more and 1000 or less, which is preferable because it increases the thermal stability and strength.

[0049] The polyimide resin preferably contains a repeating unit represented by the following chemical formula (1). [ka] (1) In the chemical formula (1), R preferably contains a biphenyl, triphenyl, or tetraphenyl structure, and R' preferably represents a structure having at least one aromatic ring within the structure. Moreover, the polyimide resin more preferably has the following structural formula (2) or (3). [ka] (2) [ka] (3)

[0050] As described above, the magnetic wedge of this embodiment is a magnetic wedge for a rotating electric machine, and the magnetic wedge comprises a plurality of flat magnetic metal particles and an intervening phase, and the flat magnetic metal particles occupy a larger proportion of the surface portion in the thickness direction of the magnetic wedge than the proportion of the central portion in the thickness direction of the magnetic wedge. Furthermore, the magnetic wedge of this embodiment is a magnetic wedge for a radial gap type rotating electric machine in which a stator is arranged facing a rotor at a predetermined radial distance, and the thickness direction is the radial direction. Furthermore, the magnetic wedge of this embodiment is a magnetic wedge used in an axial gap type rotating electric machine in which a stator is arranged facing a rotor at a predetermined axial distance, and the thickness direction is the axial direction. The magnetic wedge of this embodiment makes it possible to provide a magnetic wedge with excellent magnetic properties, such as low magnetic loss, and excellent mechanical properties, such as high strength.

[0051] (Second embodiment) The rotating electric machine of this embodiment is characterized by including the magnetic wedge of the first embodiment. Therefore, description of the same content as in the first embodiment will be omitted. In this specification, the rotating electric machine is a concept that includes all of an electric motor (motor), a generator (generator), and a motor-generator that functions as both a motor and a generator as needed.

[0052] FIG. 11 shows an example of a radial gap motor according to this embodiment. A radial gap motor includes a rotor and a stator positioned radially opposite the rotor with a predetermined gap between them. In FIG. 11, the rotor is positioned inside the stator, but it can also be positioned outside. The rotor includes a rotor core and a shaft and is supported for rotation. The stator includes a stator core, a field coil inserted into the slots in the stator core, and magnetic wedges held in the wedge grooves at the slot openings. While FIG. 11 shows an example in which the magnetic wedges are positioned as in the first embodiment, this is not limiting. In a radial gap rotating electric machine, the stator is positioned radially opposite the rotor with a predetermined gap between them, so the "gap plane" is a plane parallel to a cylindrical surface centered on the rotor's rotation axis. Therefore, the radial direction is perpendicular to the gap plane, and the axial direction and rotation direction are parallel to the gap plane. The "gap plane" is a plane passing through the gap between the rotor and stator. In FIG. 11, flat magnetic metal particles 10, intervening phases 20, magnetic wedges 100, a rotating electric machine 200, a rotor 210, a stator 220, a coil 230, a gap surface 240, and iron core teeth 250 are shown.

[0053] By arranging the magnetic wedges of the first embodiment, it is possible to reduce harmonic loss occurring on the surface of the rotor while suppressing leakage magnetic flux. In addition, the magnetic flux passing through the air gap increases, which increases the torque of the radial gap motor. High efficiency can be achieved by either or both of the above loss reduction effect and torque increase effect.

[0054] The radial gap motor may be one having a conductor in the rotor (induction motor), one having a permanent magnet (permanent magnet motor), or one having a magnetic material (reluctance motor).

[0055] FIG. 12 shows an example of an axial gap motor according to this embodiment. The axial gap motor includes a rotor and a stator facing the rotor across a predetermined axial gap. The stator includes a stator core, field coils inserted into slots in the stator core, and magnetic wedges held in wedge grooves at the slot openings. The magnetic wedges according to this embodiment reduce harmonic losses on the rotor surface while suppressing leakage flux. Furthermore, the increased magnetic flux passing through the gap increases the torque of the axial gap motor. These improvements contribute to high efficiency. While the rotor is shown between two stators in FIG. 12, it may be located on one or both sides of a single stator. In an axial gap rotating electric machine, the stator faces the rotor across a predetermined axial gap, so the "gap plane" is a plane perpendicular to the rotor's rotation axis. Therefore, the axial direction is perpendicular to the gap surface, and the rotation direction and radial direction are parallel to the gap surface. The "gap surface" is a plane passing through the gap between the rotor and the stator. Figure 12 shows flat magnetic metal particles 10, intervening phases 20, magnetic wedges 100, a rotating electric machine 200, a rotor 210, a coil 230, a gap surface 240, iron core teeth 250, a stator 270, and a shaft 280.

[0056] FIG. 13 is a schematic diagram showing an example of a generator according to this embodiment. A generator typically includes a rotor with excitation coils housed in slots in the rotor core (alternatively, a rotor using permanent magnets as an excitation source may be used) and a stator with armature coils housed in slots in the stator core. By rotating the rotor and passing an excitation current through the excitation coils, electric power is generated in the armature coils. The rotor includes a rotor core, a field coil inserted in the slots of the rotor core, and magnetic wedges held in wedge grooves at the slot openings, and is supported for rotation by bearings. The placement of the magnetic wedges according to this embodiment makes it possible to reduce harmonic losses occurring on the surface of the stator while suppressing an increase in leakage flux. Furthermore, because the magnetic flux passing through the air gap and interlinking with the armature coils increases, the generated voltage induced in the armature coils increases. As a result, high efficiency can be achieved. In Fig. 13, magnetic wedges are arranged at the slot openings of the rotor core, but they may also be arranged at the slot openings of the stator core. Also, while the figure shows a winding-type generator with an excitation coil in the rotor, a permanent magnet-type generator with a permanent magnet in the rotor may also be used. In this case, the magnetic wedges are arranged at the slot openings of the stator core. Fig. 13 shows flat magnetic metal particles 10, intervening phases 20, magnetic wedges 100, a rotating electric machine 200, a rotor 210, a stator core 222, an excitation coil 232, an armature coil 234, an air gap surface 240, and iron core teeth 250.

[0057] Since a linear motor is a flat-plate structure developed from a radial gap motor, the magnetic wedge of the present invention can also be applied to the linear motor. Specifically, the stator may include a stator core and a field coil inserted into slots in the stator core, with a magnetic wedge provided at the slot opening. Figure 14 is a schematic diagram showing an example of a linear motor according to this embodiment. In a linear motor, the moving direction of the mover, the direction perpendicular to the moving direction of the mover, and the direction perpendicular to the stator correspond to the rotation direction, axial direction, and radial direction of the radial gap motor, respectively. By using the magnetic wedge of this embodiment, it is possible to reduce harmonic losses generated on the surface of the mover while suppressing an increase in leakage magnetic flux. Furthermore, the increased magnetic flux passing through the air gap improves the thrust of the linear motor. As a result, high efficiency can be achieved. In FIG. 14, flat magnetic metal particles 10, intervening phases 20, magnetic wedges 100, stator 220, coil 230, gap surface 240, iron core teeth 250, and mover 290 are shown.

[0058] As described above, the rotating electric machine of this embodiment can suppress the increase in leakage flux due to the use of magnetic wedges and effectively alleviate the pulsation of the magnetic flux distribution on the surface of the iron core, thereby achieving high efficiency. Note that the slot shape of the rotating electric machine of this embodiment may be semi-closed slots, but is preferably open slots. This is preferable because harmonic loss can be significantly reduced.

[0059] The rotating electric machine of this embodiment can be applied to transportation systems such as railways, electric vehicles, and hybrid cars; social systems such as elevators and air conditioners; industrial systems such as robots, pumps, compressors, and fans; energy systems such as thermal power generators, hydroelectric generators, wind power generators, nuclear power generators, and geothermal power generators; and home appliances such as washing machines, thereby enabling high system efficiency. In particular, large-capacity industrial machines generally employ open slots, and therefore are preferably provided with the magnetic wedge of the first embodiment. Furthermore, traction motors for railways use form-wound coils due to the need to withstand high voltages and vibrations, and therefore employ open slots, and therefore are preferably provided with the magnetic wedge of the first embodiment.

[0060] In railways, the loss in the rotating electric machine accounts for about half of the power consumption when the train is running, so reducing the loss in the rotating electric machine has a significant effect on improving efficiency. Also, in electric vehicles and hybrid cars, the efficiency of the main motor can be improved by using the magnetic wedge of the first embodiment, thereby extending the cruising range.

[0061] The technology is expected to be highly effective in hydroelectric generators, especially variable-speed pumped-storage generators, and also in wind power generators.

[0062] (Example) Example 1 will be described in more detail below in comparison with Comparative Example 1.

[0063] Example 1 First, a ribbon of Fe-Co-Si-B (Fe70Co30B25 (at%)-4 wt%Si) was produced using a single-roll quenching device. The resulting ribbon was then heat-treated at 300°C in a H2 atmosphere. Next, this ribbon was pulverized using a mixer to obtain flat magnetic metal particles (the average thickness was approximately 15 μm, and the average ratio of the average length within the flat surface to the thickness was approximately 30). The resulting flat magnetic metal particles were then mixed with an imide-based resin and molded. Molding was carried out according to Figure 10. That is, a molding die was used that was magnetized in a direction perpendicular to the direction of application of press pressure. The gap between the mold die and the mold punch was approximately 50 μm. Furthermore, when applying press pressure in one axis direction, a magnetic field was applied in a direction perpendicular to the direction of application of press pressure. Subsequently, hot press molding was performed while applying a magnetic field to produce magnetic wedges. For the magnetic wedge fabricated, the sum (SAm) of all the areas (Am) of the individual flat magnetic metal particles in the observed region of the center and surface areas was calculated in a cross section including the width and thickness directions of the magnetic wedge. The area (At) of the observed region was calculated, and the percentage (area ratio: SAm / At) was determined. Three cross sections were observed and evaluated. The average value was taken as the percentage of magnetic metal particles in the center and surface areas of the magnetic wedge. The area of ​​each flat magnetic particle and the area of ​​the entire observation region were calculated from images obtained by SEM observation using the image processing software ImageJ. As a result, it was confirmed that the ratio of the percentage of flat magnetic metal particles in the surface area to the percentage in the center area was 1.7.

[0064] (Comparative Example 1) The molding method was the same as in Example 1, except that the flat magnetic metal particles were uniformly stacked and oriented by simple hot press molding, which was not magnetized in a direction perpendicular to the direction of application of the press pressure, and then cutting out the particles. It was confirmed that the ratio of the flat magnetic metal particles in the surface area to the center area of ​​the manufactured magnetic wedge was approximately 1.

[0065] Table 1 shows the magnetic properties of the magnetic wedge of this embodiment, the degree of improvement in efficiency as a rotating electrical machine, and the mechanical properties (the bending strength is shown as an example) together with those of Comparative Example 1.

[0066] (1) Magnetic permeability: The magnetic permeability is measured at 100 Hz. The magnetic permeability is shown as a ratio based on the iron loss of Comparative Example 1.

[0067] (2) Degree of efficiency improvement as a rotating electrical machine: Using a standard radial gap motor as a motif, the degree of efficiency improvement is calculated based on the efficiency when a non-magnetic wedge is used. The degree of efficiency improvement is shown as a ratio based on the degree of efficiency improvement in Comparative Example 1.

[0068] (3) Strength: The flexural strength of the evaluation sample at 25°C was measured, and expressed as a ratio to the flexural strength of the sample of Comparative Example 1 at 25°C (= flexural strength of evaluation sample at 25°C / flexural strength of sample of Comparative Example 1 at 25°C).

[0069] (4) Change in strength over time: After heating the evaluation sample at 100°C in the air for 100 hours, measure the flexural strength at 25°C and calculate the change over time (flexural strength after 100 hours / flexural strength before flexural strength).

[0070] [Table 1]

[0071] Table 1 shows that Example 1 has improved magnetic permeability, the degree of efficiency improvement as a rotating electric machine, strength, and the rate of change in strength over time compared to Comparative Example 1. When the proportion of flat magnetic metal particles is high in the surface region, as in Example 1, the progression of thermal decomposition from the material surface is suppressed, achieving higher heat resistance than in the case of a uniform distribution, and it is thought that this is why the rate of change in strength over time is significantly improved. It was also found that the presence of many flat magnetic metal particles on the surface suppresses the progression of cracks, achieving higher strength than in the case of a uniform distribution (Comparative Example 1). Furthermore, it was found that concentrating flat magnetic metal particles in the surface region increases the magnetic permeability in the surface region, thereby increasing the effective magnetic permeability overall. It was found that this improves the efficiency of the rotating electric machine.

[0072] Although several embodiments and examples of the present invention have been described, these embodiments and examples are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims.

[0073] The above-described embodiments can be summarized as the following technical proposals. (Technical proposal 1) A magnetic wedge for a rotating electric machine, the magnetic wedge comprises a plurality of flat magnetic metal particles and an intervening phase; the flat magnetic metal particles occupy a larger proportion of the surface portion in the thickness direction of the magnetic wedge than the proportion of the central portion in the thickness direction of the magnetic wedge; magnetic wedge. (Technical proposal 2) The magnetic wedge is for a radial gap type rotating electric machine in which a stator is disposed facing a rotor at a predetermined radial distance, The thickness direction is the radial direction. The magnetic wedge described in Technical Proposal 1. (Technical proposal 3) The flat surfaces of the flat magnetic metal particles are oriented in the rotation direction and axial direction of the rotating electric machine. Magnetic wedge as described in Technical Proposal 2. (Technical proposal 4) A magnetic wedge used in an axial gap type rotating electric machine in which a stator is disposed facing a rotor at a predetermined axial distance, The thickness direction is the axial direction. The magnetic wedge described in Technical Proposal 1. (Technical proposal 5) The flat surfaces of the flat magnetic metal particles are oriented in the rotation direction and radial direction of the rotating electric machine. Magnetic wedge as described in Technical Proposal 4. (Technical proposal 6) A magnetic wedge according to any one of technical proposals 1 to 5, wherein the ratio of the flat magnetic metal particles in the surface portion to the central portion is 1.1 or more and 2 or less. (Technical proposal 7) The flat magnetic metal particles have an average thickness of 10 nm or more and 100 μm or less, and have the flat surfaces and a magnetic metal phase containing at least one first element selected from the group consisting of Fe, Co, and Ni, and the average value of the ratio of the average length within the flat surfaces to the thickness is 5 or more and 10,000 or less, The intervening phase is present between the flat magnetic metal particles and contains at least one second element selected from the group consisting of oxygen (O), carbon (C), nitrogen (N) and fluorine (F). A magnetic wedge according to any one of technical proposals 1 to 6. (Technical proposal 8) The average thickness of the plurality of flat magnetic metal particles is 10 μm or more and 30 μm or less below A magnetic wedge according to Technical Solution 7, wherein the average ratio of the average length to the thickness of the flat magnetic metal particles is 10 or more and 100 or less. (Technical proposal 9) A magnetic wedge according to any one of Technical Schemes 1 to 8, wherein the intervening phase contains a resin. (Technical proposal 10) A magnetic wedge described in any one of Technical Schemes 1 to 9, wherein at least a portion of the surface of the flat magnetic metal particle is covered with a coating layer having a thickness of 0.1 nm or more and 1 μm or less and containing at least one second element selected from the group consisting of oxygen (O), carbon (C), nitrogen (N) and fluorine (F). (Technical proposal 11) A magnetic wedge according to any one of technical solutions 1 to 10, having a difference in coercive force depending on the direction in a plane parallel to the flat surface. (Technical proposal 12) A rotating electric machine equipped with a magnetic wedge according to any one of technical proposals 1 to 11.

[0074] Furthermore, the above embodiments can be summarized as the following technical solutions. (Technical proposal 1) A plurality of flat magnetic metal particles; an intervening phase; A magnetic wedge comprising: the flat magnetic metal particles occupy a larger proportion of the surface portion in the thickness direction of the magnetic wedge than the proportion of the central portion in the thickness direction of the magnetic wedge; magnetic wedge. (Technical proposal 2) The magnetic wedge is a rotor that rotates around an axial direction in a direction perpendicular to the axial direction; a stator disposed opposite the rotor at a predetermined interval in a radial direction perpendicular to the axial direction and the rotation direction; The rotor or the stator of a radial gap type rotating electric machine is used, The longitudinal direction of the magnetic wedge is the axial direction, the thickness direction of the magnetic wedge is the radial direction; the width direction of the magnetic wedge is the rotation direction; The flat magnetic metal particles occupy a larger proportion of the surface portion in the radial direction than a proportion of the center portion in the radial direction. The magnetic wedge described in Technical Proposal 1. (Technical proposal 3) The flat surfaces of the flat magnetic metal particles are oriented in the rotation direction and the axial direction of the rotating electric machine. Magnetic wedge as described in Technical Proposal 2. (Technical proposal 4) The magnetic wedge is a rotor that rotates around an axial direction in a direction perpendicular to the axial direction; a rotor disposed opposite to the rotor at a predetermined interval in the axial direction; The rotor or the stator of an axial gap type rotating electric machine is used in the rotor or the stator, The longitudinal direction of the magnetic wedge is a radial direction, the thickness direction of the magnetic wedge is the axial direction; the width direction of the magnetic wedge is the rotation direction; The flat magnetic metal particles occupy a larger proportion of the surface portion in the axial direction than a proportion of the center portion in the axial direction. The magnetic wedge described in Technical Proposal 1. (Technical proposal 5) The flat surfaces of the flat magnetic metal particles are oriented in the rotation direction and the radial direction of the rotating electric machine. Magnetic wedge as described in Technical Proposal 4. (Technical proposal 6) A magnetic wedge according to any one of technical proposals 1 to 5, wherein the ratio of the flat magnetic metal particles in the surface portion to the central portion is 1.1 or more and 2 or less. (Technical proposal 7) The plurality of flat magnetic metal particles have an average thickness of 10 nm or more and 100 μm or less, have flat surfaces, and a magnetic metal phase containing at least one first element selected from the group consisting of Fe, Co, and Ni, and the average value of the ratio of the average length within the flat surfaces to the thickness is 5 or more and 10,000 or less, The intervening phase is present between the flat magnetic metal particles and contains at least one second element selected from the group consisting of oxygen (O), carbon (C), nitrogen (N) and fluorine (F). A magnetic wedge according to any one of technical proposals 1 to 6. (Technical proposal 8) The average thickness of the plurality of flat magnetic metal particles is 10 μm or more and 30 μm or less belowA magnetic wedge according to Technical Solution 7, wherein the average ratio of the average length to the thickness of the flat magnetic metal particles is 10 or more and 100 or less. (Technical proposal 9) A magnetic wedge according to any one of Technical Schemes 1 to 8, wherein the intervening phase contains a resin. (Technical proposal 10) A magnetic wedge described in any one of Technical Schemes 1 to 9, wherein at least a portion of the surface of the flat magnetic metal particle is covered with a coating layer having a thickness of 0.1 nm or more and 1 μm or less and containing at least one second element selected from the group consisting of oxygen (O), carbon (C), nitrogen (N) and fluorine (F). (Technical proposal 11) A magnetic wedge according to any one of technical solutions 1 to 10, having a difference in coercive force depending on the direction in a plane parallel to the flat surface. (Technical proposal 12) A rotating electric machine equipped with a magnetic wedge according to any one of technical proposals 1 to 11. [Explanation of symbols]

[0075] 6: Flat surface 9: Coating layer 10: Flat magnetic metal particle 20: Intervening phase 100: Magnetic wedge 200: Rotating electric machine 210: Rotor 220: Stator 222: Stator core 230: Coil 232: Excitation coil 234: Armature coil 240: Air gap surface 250: Core teeth 260: Core slot 270: Stator 280: Shaft 290: Movement

Claims

1. A magnetic wedge used in a radial gap type rotating electric machine in which a stator is disposed facing a rotor at a predetermined radial distance, the magnetic wedge comprises a plurality of flat magnetic metal particles and an intervening phase; the flat magnetic metal particles occupy a larger proportion of the surface portion in the thickness direction of the magnetic wedge than the proportion of the central portion in the thickness direction of the magnetic wedge; the thickness direction is the radial direction, The flat surfaces of the flat magnetic metal particles are oriented in at least one direction, namely, the rotation direction and the axial direction of the rotating electric machine. magnetic wedge.

2. A magnetic wedge used in an axial gap type rotating electric machine in which a stator is arranged facing a rotor at a predetermined axial distance, the magnetic wedge comprises a plurality of flat magnetic metal particles and an intervening phase; the flat magnetic metal particles occupy a larger proportion of the surface portion in the thickness direction of the magnetic wedge than the proportion of the central portion in the thickness direction of the magnetic wedge; the thickness direction is the axial direction, The flat surfaces of the flat magnetic metal particles are oriented in at least one direction of the rotation direction and the radial direction of the rotating electric machine. magnetic wedge.

3. 3. The magnetic wedge according to claim 1, wherein the ratio of the flat magnetic metal particles in the surface portion to the central portion is 1.1 or more and 2 or less.

4. The flat magnetic metal particles have an average thickness of 10 nm or more and 100 μm or less, and have the flat surfaces and a magnetic metal phase containing at least one first element selected from the group consisting of Fe, Co, and Ni, and the average value of the ratio of the average length within the flat surfaces to the thickness is 5 or more and 10,000 or less, The intervening phase is present between the flat magnetic metal particles and contains at least one second element selected from the group consisting of oxygen (O), carbon (C), nitrogen (N), and fluorine (F).

3. The magnetic wedge according to claim 1 or 2.

5. A magnetic wedge as described in claim 4, wherein the average thickness of the plurality of flat magnetic metal particles is 10 μm or more and 30 μm or less, and the average value of the ratio of the average length to the thickness of the flat magnetic metal particles is 10 or more and 100 or less.

6. 3. The magnetic wedge according to claim 1, wherein the intervening phase contains a resin.

7. A magnetic wedge as described in claim 1 or claim 2, wherein at least a portion of the surface of the flat magnetic metal particle is covered with a coating layer having a thickness of 0.1 nm or more and 1 μm or less and containing at least one second element selected from the group consisting of oxygen (O), carbon (C), nitrogen (N) and fluorine (F).

8. 3. The magnetic wedge according to claim 1, wherein the magnetic wedge has a difference in coercive force depending on the direction in a plane parallel to the flat surface.

9. A rotating electric machine comprising the magnetic wedge according to claim 1 or 2.

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