Magnetic wedges and rotating electric machines

Abstract

To provide a magnetic wedge and a rotary electric machine having excellent electrical characteristics, and heat resistance (electrical characteristics, magnetic characteristics, and mechanical characteristics).SOLUTION: A magnetic wedge of an embodiment is a magnetic wedge of a rotary electric machine. The magnetic wedge comprises a plurality of flat magnetic metal particles, and an interposition phase. A surface coating layer is present in at least part of a surface of the magnetic wedge.SELECTED DRAWING: Figure 10

Description

Technical Field

[0001] Embodiments of the present invention relate to a magnetic wedge and a rotating electrical machine.

Background Art

[0002] Generally, the coil windings of a rotating electrical machine are housed in iron core slots and are supported and fixed by wedges provided at the slot openings. A non-magnetic material is generally adopted for the material of this wedge. However, since the magnetic resistance value in the air gap between the stator core and the rotor core becomes discontinuous, pulsations occur in the magnetic flux distribution on the core surface portion facing the wedge through the air gap, and the harmonic loss increases. For the purpose of reducing this harmonic loss, and also, a wedge having an appropriate amount of magnetism (magnetic wedge) is provided. By applying a magnetic wedge, the harmonic loss is reduced and the efficiency of the rotating electrical machine is improved. FIG. 1 is a schematic diagram of the use state and effect of a magnetic wedge. In FIG. 1, a radial gap type rotating electrical machine is shown as an example. In FIG. 1, a magnetic wedge 100, a coil 230, a core tooth 250, and a core slot 260 are shown.

[0003] Needless to say, the higher the magnetic permeability of the magnetic wedge, the more the harmonic loss can be reduced. However, as shown in FIG. 1, since the magnetic wedge is arranged so as to bridge between adjacent core teeth, there is a drawback that the leakage magnetic flux flowing between the core teeth through the magnetic wedge increases. In addition, existing magnetic wedges have a low saturation magnetization, so they are likely to cause magnetic saturation. Furthermore, since the loss is large (the coercive force is high, so the hysteresis loss is large, and the electrical resistivity is low, so the eddy current loss is large), the improvement range of the efficiency of the rotating electrical machine is limited. In addition, existing magnetic wedges have a low magnetic permeability, so the improvement range of the efficiency of the rotating electrical machine is limited, and they are insufficient in terms of thermal stability and mechanical properties (strength, toughness). Therefore, it is desired to improve the characteristics of the magnetic wedge in terms of saturation magnetization, magnetic permeability, loss, strength, toughness, etc. In particular, it is desired to improve the magnetic characteristics, electrical characteristics, and thermomechanical characteristics of the magnetic wedge.

Prior Art Documents

Patent Documents

[0004] [Patent Document 1] Japanese Utility Model Publication No. 58-6572 [Overview of the project] [Problems that the invention aims to solve]

[0005] The magnetic wedge of the embodiment is a magnetic wedge for a rotating electric machine, and the magnetic wedge comprises a plurality of flattened magnetic metal particles, Multiple flattened magnetic metal surface particles located perpendicular to the longitudinal direction of the magnetic wedge and closest to the widthwise contour line in the cross-section at the center of the longitudinal direction, The magnetic wedge has an intervening phase, and a surface coating layer is present on at least a portion of the surface of the magnetic wedge. Furthermore, the thickness of the surface coating layer is equal to or greater than the average thickness of the flat magnetic metal surface particles. [Means for solving the problem]

[0006] The magnetic wedge of this embodiment is a magnetic wedge for a rotating electric machine, and the magnetic wedge comprises a plurality of flattened magnetic metal particles and an intervening phase, and a surface coating layer is present on at least a portion of the surface of the magnetic wedge. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic diagram illustrating the usage and effects of magnetic wedges. [Figure 2] This is a schematic diagram of the flattened magnetic metal particles in the magnetic wedge of the first embodiment. [Figure 3] This is a conceptual diagram showing an example of how to determine the thickness of the flattened magnetic metal particles in the magnetic wedge of the first embodiment. [Figure 4] This is a conceptual diagram illustrating how to determine the maximum and minimum lengths of the flattened magnetic metal particles within the flattened plane in the magnetic wedge of the first embodiment. [Figure 5] This is a conceptual diagram illustrating another example of how to determine the maximum and minimum lengths of flattened magnetic metal particles within the flattened plane in a magnetic wedge according to the first embodiment. [Figure 6] This is a schematic diagram showing the directions when measuring the coercivity of a magnetic wedge according to the first embodiment, by changing the direction at 22.5-degree intervals with respect to the 360-degree angle within the flattened plane of the flattened magnetic metal particles. [Figure 7]This is a schematic diagram of the magnetic wedge according to the first embodiment. [Figure 8] This is a schematic diagram of the magnetic wedge according to the first embodiment. [Figure 9] This is another schematic diagram of the magnetic wedge according to the first embodiment. [Figure 10] This is a schematic diagram showing an example of a radial gap type rotating electric machine according to the second embodiment. [Figure 11] This is a schematic diagram showing an example of an axial gap type rotating electric machine according to the second embodiment. [Figure 12] This is a schematic diagram showing an example of a generator according to the second embodiment. [Figure 13] This is a schematic diagram showing an example of a linear motor according to the second embodiment. [Modes for carrying out the invention]

[0008] Embodiments will be described below with reference to the drawings. In the drawings, identical or similar parts are denoted by the same or similar reference numerals. Unless otherwise specified in this specification, measurements are performed at 25°C.

[0009] In this specification, the "axial direction," "rotational direction," and "radial direction" are defined with respect to the rotor of the rotating electric machine. That is, the "axial direction" means the direction along the rotor's axis of rotation, the "rotational direction" means the circumferential direction (or tangential direction) around the rotor's axis of rotation, and the "radial direction" means the direction perpendicular (perpendicular) to the rotor's axis of rotation.

[0010] (First Embodiment) The magnetic wedge of this embodiment is a magnetic wedge for a rotating electric machine, and the magnetic wedge comprises a plurality of flattened magnetic metal particles and an intervening phase, and a surface coating layer is present on at least a portion of the surface of the magnetic wedge.

[0011] The flat magnetic metal particles are flat particles having a flaky or flattened shape. Note that the flat magnetic metal particles can be replaced with magnetic metal particles of any shape other than flaky. The magnetic wedge of the present embodiment exhibits an effect by covering at least a part of the surface of the magnetic wedge with a surface coating layer. Therefore, magnetic metal particles having a shape other than flaky can also exhibit excellent magnetic properties, electrical properties, and thermomechanical properties. In particular, when having a flaky shape, an improvement in more excellent magnetic properties, electrical properties, and thermomechanical properties can be expected.

[0012] FIG. 2 is a schematic diagram of the flat magnetic metal particles in the magnetic wedge of the first embodiment. The coating layer 9 and the flat magnetic metal particles 10 are shown.

[0013] 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 further preferably contains at least one second element selected from the group consisting of oxygen (O), carbon (C), nitrogen (N), and fluorine (F).

[0014] As the non-magnetic metal, Al and Si are particularly preferable from the viewpoint of thermal stability. 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 more preferably contains at least one of the same non-magnetic metals as the non-magnetic metal that is one of the constituent components of the flat magnetic metal particles.

[0015] Among oxygen (O), carbon (C), nitrogen (N), and fluorine (F), it is preferable to contain oxygen (O), and it is preferable to be an oxide or a composite oxide.

[0016] The above considerations are based on ease of coating layer formation, oxidation resistance, and thermal stability. As a result, the adhesion between the flat magnetic metal particles and the coating layer can be improved, and the thermal stability and oxidation resistance of the magnetic wedge, described later, can be improved. The coating layer can improve not only the thermal stability and oxidation resistance of the flat magnetic metal particles, but also the electrical resistance of the flat magnetic metal particles. By increasing the electrical resistance, eddy current losses can be suppressed and the frequency characteristics of the magnetic permeability can be improved. 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 is preferable.

[0017] Furthermore, the presence of a coating layer is also preferable from a magnetic standpoint. Since the thickness of the flattened magnetic metal particles is small relative to the size of the flattened surface, they can be considered as a pseudo-thin film. In this case, when a coating layer is formed on the surface of the flattened magnetic metal particles and integrated, it can be considered as a pseudo-layered thin film structure, and the magnetic domain structure is energetically stabilized. This reduces coercivity, which in turn reduces hysteresis loss, and is therefore preferable. At this time, the permeability is also increased, which is preferable. From this viewpoint, it is even more preferable that the coating layer is non-magnetic, as this makes it easier to stabilize the magnetic domain structure.

[0018] The thickness of the coating layer is preferably between 0.1 nm and 1 μm. This thickness range allows for appropriate thermal stability, oxidation resistance, and electrical resistance while preventing the saturation magnetization from becoming too small and suppressing a decrease in permeability. Furthermore, from a magnetic standpoint, it does not impair the effects of stabilizing the magnetic domain structure, resulting in lower coercivity, lower losses, and higher permeability. More preferably, the thickness of the coating layer is between 0.1 nm and 100 μm.

[0019] The thickness of a flattened magnetic metal particle refers to the average thickness of a single flattened magnetic metal particle. Any method that can determine the average thickness of a single flattened magnetic metal particle is acceptable.

[0020] For example, one could observe a cross-section of a flattened magnetic metal particle perpendicular to its flattened plane using a transmission electron microscope (TEM), scanning electron microscope (SEM), or optical microscope. Then, in the observed cross-section of the flattened magnetic metal particle, select at least 10 arbitrary locations within the direction of the flattened plane, measure the thickness at each selected location, and use the average value.

[0021] Alternatively, in the cross-section of the observed flattened magnetic metal particle, one may select at least 10 locations at equal intervals from one end to the other in the direction of the flattened plane (in this case, it is preferable not to select the ends and other ends as they are special locations), measure the thickness at each selected location, and use the average value.

[0022] Figure 3 is a conceptual diagram showing an example of how to determine the thickness of the flattened magnetic metal particles in the magnetic wedge of the first embodiment. Figure 3 specifically shows how to determine the thickness in this case. Ten locations are selected at equal intervals in the direction of the flattened plane, from one end to the other (excluding the ends), and the thickness at each location is recorded as t1, t2, ..., t 10 In this case, the thickness of the flattened magnetic metal particles is (t1 + t2 + ... + t 10 ) / 10. It is preferable to measure as many points as possible during measurement, as this allows for obtaining average information. Furthermore, if the cross-sectional contour is highly irregular or the surface contour is rough, making it difficult to determine the average thickness in its current state, it is preferable to smooth the contour with an average straight line or curve, as appropriate depending on the situation, before performing the above method.

[0023] Furthermore, average thickness refers to the average value of the thicknesses of multiple flattened magnetic metal particles, and is distinct from the simple "thickness" mentioned above.

[0024] When determining the average thickness, it is preferable to use the average value obtained from 20 or more flattened magnetic metal particles. Furthermore, it is preferable to use as many flattened magnetic metal particles as possible to obtain average information. If it is not possible to observe 20 or more flattened magnetic metal particles, it is preferable to observe as many flattened magnetic metal particles as possible and use the average value obtained from them.

[0025] The average thickness of the flattened magnetic metal particles is preferably 10 nm to 100 μm. More preferably 10 nm to 1 μm, and even more preferably 10 nm to 100 nm. Furthermore, it is preferable that the flattened 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. These features are preferable because they allow for sufficiently small eddy current losses when a magnetic field is applied in a direction parallel to the flattened plane. Furthermore, a smaller thickness is preferable because the magnetic moment is confined in a direction parallel to the flattened plane, making it easier for magnetization to proceed through rotational magnetization. When magnetization proceeds through rotational magnetization, the magnetization tends to proceed reversibly, resulting in a smaller coercivity, which is preferable because it reduces hysteresis losses.

[0026] The average length of a flattened magnetic metal particle is defined as (a+b) / 2, where a is the maximum length and b is the minimum length within the flattened plane. The maximum length a and minimum length b can be determined as follows. For example, consider the rectangle with the smallest area that is circumscribed around the flattened plane. Let the length of the longer side of that rectangle be the maximum length a, and the length of the shorter side be the minimum length b.

[0027] Figure 4 is a conceptual diagram illustrating how to determine the maximum and minimum lengths within the flattened plane of a flattened magnetic metal particle in a magnetic wedge according to the first embodiment. Figure 4 is a schematic diagram showing the maximum length a and minimum length b determined by the above method, using several flattened magnetic metal particles as examples. The maximum length a and minimum length b, like the average thickness, can be determined by observing the flattened magnetic metal particle with a TEM, SEM, or optical microscope.

[0028] Furthermore, it is possible to determine the maximum length a and minimum length b by performing image analysis of microscopic photographs on a computer. In either case, it is preferable to perform the determination on 20 or more flattened magnetic metal particles. Moreover, it is preferable to perform the determination on as many flattened magnetic metal particles as possible in order to obtain average information.

[0029] Furthermore, if it is not possible to observe 20 or more flattened magnetic metal particles, it is preferable to observe as many flattened magnetic metal particles as possible and adopt the average value obtained from them. In this case, since it is preferable to obtain the average value as much as possible, it is preferable to perform observation or image analysis when the flattened magnetic metal particles are uniformly dispersed (in a state in which multiple flattened magnetic metal particles with different maximum and minimum lengths are dispersed as randomly as possible). For example, it is preferable to perform observation or image analysis by thoroughly mixing multiple flattened magnetic metal particles and sticking them onto a tape, or by dropping multiple flattened magnetic metal particles from above and letting them fall and stick onto a tape.

[0030] However, depending on the type of flattened magnetic metal particle, the method used to determine the maximum length a and minimum length b may not accurately reflect the true nature of the particle. Figure 5 is a conceptual diagram illustrating another example of how to determine the maximum and minimum lengths within the flattened plane of a flattened magnetic metal particle in the magnetic wedge of the first embodiment.

[0031] For example, in the case shown in Figure 5, the flattened magnetic metal particles are in a long, curved shape. In this case, the maximum and minimum lengths of the flattened magnetic metal particles are essentially the lengths a and b shown in Figure 5. Thus, the maximum lengths a and b cannot be determined in a completely unique way. Basically, it is acceptable to consider the rectangle with the smallest area that is circumscribing the flattened plane, and set the length of the longer side of that rectangle as the maximum length a and the length of the shorter side as the minimum length b. However, depending on the shape of the particles, if this method does not capture the essence, the maximum and minimum lengths a and b should be determined flexibly to capture the essence. The thickness t is defined as the length perpendicular to the flattened plane. The ratio A of the average length within the flattened plane to the thickness is defined as A = ((a+b) / 2) / t, using the maximum length a, minimum length b, and thickness t.

[0032] The average value of the ratio of the average length within the flattened plane to the thickness of the flattened magnetic metal particles is preferably between 5 and 10,000. This is because it increases the magnetic permeability. Furthermore, it allows for a higher ferromagnetic resonance frequency, thereby reducing ferromagnetic resonance losses.

[0033] The ratio of the average length within the flattened plane to the thickness is calculated using the average value. Preferably, the average value obtained over 20 or more flattened magnetic metal particles is used. Furthermore, it is preferable to obtain average information by examining as many flattened magnetic metal particles as possible. If it is not possible to observe 20 or more flattened magnetic metal particles, it is preferable to observe as many flattened magnetic metal particles as possible and use the average value obtained over them. For example, if there are particles Pa, Pb, and Pc, and their respective thicknesses are Ta, Tb, and Tc, and their average lengths within the flattened plane are La, Lb, and Lc, then the average thickness is calculated as (Ta + Tb + Tc) / 3, and the average value of the ratio of the average length within the flattened plane to the thickness is calculated as (La / Ta + Lb / Tb + Lc / Tc) / 3.

[0034] It is preferable that the flattened magnetic metal particles have a difference in coercivity depending on the direction within the flattened plane. The larger the percentage of the difference in coercivity depending on the direction, the better, and it is preferable that it is 1% or more. More preferably, the percentage of the difference in coercivity is 10% or more, even more preferably 50% or more, and even more preferably 100% or more.

[0035] The coercivity difference ratio referred to here is defined as (Hc(max)-Hc(min)) / Hc(min) × 100(%), using the maximum coercivity Hc(max) and minimum coercivity Hc(min) within the flattened plane. Coercivity can be evaluated using a vibrating sample magnetometer (VSM), etc. If the coercivity is low, a low-field unit can be used to measure coercivity of 0.1Oe or less. Measurements are performed by changing the direction within the flattened plane relative to the direction of the measurement magnetic field.

[0036] "Having a coercivity difference" means that when a magnetic field is applied in all 360 degrees within a flattened plane and the coercivity is measured, there is a direction in which the coercivity is maximum and a direction in which the coercivity is minimum. For example, when the coercivity is measured by changing the direction every 22.5 degrees with respect to the 360-degree angle within a flattened plane, a coercivity difference appears; that is, there is an angle in which the coercivity is greater and an angle in which the coercivity is smaller. In this case, it is said that "a coercivity difference exists." Figure 6 is a schematic diagram showing the directions in which the coercivity is measured by changing the direction every 22.5 degrees with respect to the 360-degree angle within the flattened plane of the flattened magnetic metal particles in the magnetic wedge of the first embodiment. In Figure 6, the flattened plane of the flattened magnetic metal particles is shown as viewed from above.

[0037] Having a difference in coercivity within the flattened plane is preferable because it reduces the minimum coercivity value compared to the isotropic case where there is almost no difference in coercivity. In materials with magnetic anisotropy within a flattened plane, there is a difference in coercivity depending on the direction within the flattened plane, and the minimum coercivity value is smaller compared to magnetically isotropic materials. This reduces hysteresis loss and improves permeability, which is preferable. Figure 6 shows flattened magnetic metal particles 10 and a flattened plane 6.

[0038] Furthermore, the flattened magnetic metal particles have a magnetic metal phase containing at least one first element selected from the group consisting of Fe, Co, and Ni. The flattened 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 easily imparts a moderately large magnetic anisotropy, thereby improving the magnetic properties described above. In addition, the Fe-Co system is preferable because it easily achieves high saturation magnetization. Furthermore, it is preferable that the composition range of Fe and Co falls within the above range, as this allows for the achievement of even higher saturation magnetization.

[0039] Elements can be easily analyzed using methods such as EDX (Energy Dispersive X-ray spectroscopy) and ICP (Inductively Coupled Plasma) emission spectroscopy.

[0040] The flattened 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 enhances the thermal stability and oxidation resistance of the flattened magnetic metal particles. Among these, Al and Si are particularly preferred because they readily form solid solutions with Fe, Co, and Ni, which are the main components of the flattened magnetic metal particles, and contribute to improving thermal stability and oxidation resistance.

[0041] Furthermore, in order to induce magnetic anisotropy, there is also a method of making the crystallinity of the flattened magnetic metal particles as amorphous as possible and inducing magnetic anisotropy in one direction in the plane by a magnetic field or strain. In this case, it is desirable to have a composition that makes it easy to make the flattened magnetic metal particles as amorphous as possible. From this viewpoint, it is preferable that the magnetic metal contained in the flattened 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).

[0042] 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. It is also preferable that the additive element is such that the enthalpy of mixture between the at least one first element selected from the group consisting of Fe, Co, and Ni and the additive element becomes negatively large. Furthermore, it is preferable that the system consists of a total of three or more elements, including the first element and the additive element. In addition, metalloid additive elements such as B and Si are advantageous when mixed into the system because they have a slow crystallization rate and are prone to amorphous formation.

[0043] From the above viewpoints, B, Si, P, Ti, Zr, Hf, Nb, Y, Cu, etc. are preferred, and among them, it is more preferable that the additive element contains one of B, Si, Zr, Hf, or Y. For example, it is preferable that the first element of the magnetic metal phase contains Fe and Co, and the additive elements contain Si and B.

[0044] Furthermore, it is preferable that the total amount of the additive elements is 0.001 at% or more and 80 at% or less relative to the total amount of the first element and the additive elements. More preferably, it is 5 at% or more and 80 at% or less, and even more preferably, 10 at% or more and 40 at% or less. Furthermore, while a larger total amount of the aforementioned additive elements is preferable because it promotes amorphization and facilitates the imparting of magnetic anisotropy (i.e., preferable from the viewpoint of low loss and high permeability), it is undesirable because it reduces the proportion of the magnetic metal phase, resulting in a lower saturation magnetization. For these reasons, it is important to select the composition and amount of additive elements by considering all factors, including high saturation magnetization, low loss, and high permeability.

[0045] 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 electrical resistance. Preferably, the electrical resistivity of the intervening phase is higher than that of the flattened magnetic metal particles. This is because it can reduce eddy current losses in the flattened magnetic metal particles. Since the intervening phase surrounds the flattened magnetic metal particles, it is preferable that it can improve the oxidation resistance and thermal stability of the flattened 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 flattened magnetic metal particles together, so it is also preferable from the viewpoint of high strength.

[0046] The intervening phase preferably contains a resin. Suitable resins 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, or copolymers thereof.

[0047] In particular, to achieve high thermal stability, the intervening phase preferably contains a highly heat-resistant silicone resin, polyimide resin, imide resin, or bismaleimide resin. Epoxy resins, phenolic resins, and polyester resins are preferred because they are relatively heat-resistant, high-strength, and versatile resins.

[0048] Furthermore, the intervening phase preferably contains at least one resin selected from the group consisting of bismaleimide resins, polyimide resins, polyester resins, phenolic resins, epoxy resins, and silicone resins. In addition, it is preferable that the weight increase rate after exposure to air at room temperature for one week after exposure to air at 120°C for 30 minutes is 1% or less, and more preferably 0.1% or less.

[0049] Furthermore, the resin contained in the intervening phase preferably has a water absorption rate of 1% or less, as defined in ISO 62:1999 (JIS K7209:2000), and more preferably 0.1% or less. To increase strength, the intervening phase preferably also contains materials such as FRP (Fiber-Reinforced Plastics) which is a mixture of fibers such as glass fibers, aramid fibers, carbon fibers, Zylon fibers, polyethylene fibers, and boron fibers. As a result, the bonding between the flat magnetic metal particles and the intervening phase becomes stronger, and thermal stability and mechanical properties such as strength and toughness are easily improved.

[0050] The intervening phase surrounding the flattened magnetic particles provides excellent oxidation resistance, and the degradation of magnetic properties due to oxidation of the flattened magnetic metal particles is less likely to occur, which is desirable. The type of resin can be identified by IR (Infrared Spectroscopy), NMR (Nuclear Magnetic Resonance), etc.

[0051] Bismaleimide resins are preferable because they can be molded at relatively low temperatures (e.g., 180°C or below) and can therefore be molded using general-purpose low-temperature hot press equipment. They are also preferable because they offer high thermal stability and excellent mechanical properties after molding. Furthermore, they are easily composited (bonded) with flattened magnetic metal particles, and are preferable because they easily achieve excellent properties in terms of thermal stability and mechanical properties such as strength and toughness as a composite material. In addition, the intervening phase easily surrounds the flattened magnetic particles, making it less likely for the magnetic properties of the flattened magnetic metal particles to deteriorate due to oxidation, which is also preferable.

[0052] Bismaleimide resins are preferably given a glass transition temperature of 250°C or higher. This is desirable because it enhances thermal stability and strength.

[0053] Bismaleimide resins specifically include 4,4′-diphenylmethanebismaleimide, phenylmethanebismaleimide, m-phenylenebismaleimide, bisphenol A diphenyl ether bismaleimide, 3,3′-dimethyl-5,5′-diethyl-4,4′-diphenylmethanebismaleimide, 4-methyl-1,3-phenylenebismaleimide, 1,6′-bismaleimide-(2,2,4-trimethyl)hexane, 2,2′-diallylbisphenol A, and 4,4′-diphenyl It is preferable to include leuetherbismaleimide, 4,4′-diphenylsulfonebismaleimide, 1,3-bis(3-maleimidophenoxy)benzene, 1,3-bis(4-maleimidophenoxy)benzene, bis(3-ethyl-5-methyl-4-maleimidophenyl)methane, 2,2′-bis[4-(4-maleimidophenoxy)phenyl]propane, etc. (It is preferable to include the above as monomers because bismaleimide resins are produced by polymerizing these monomers). This is preferable because it increases thermal stability and strength.

[0054] Furthermore, the curing agent for curing the monomer preferably includes 4,4′-diaminodiphenylmethane, diaminodiphenyl ether, diaminodiphenyl sulfone, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, o,o′-diallylbisphenol A, etc. However, other types of curing agents are also acceptable as long as they are effective in properly curing the monomer.

[0055] Preferred combinations of monomers and curing agents include, for example, 4,4′-diphenylmethanebismaleimide and 4,4′-diaminodiphenylmethane. When 4,4′-diphenylmethanebismaleimide and 4,4′-diaminodiphenylmethane are included, the ratio of 4,4′-diphenylmethanebismaleimide to 4,4′-diaminodiphenylmethane is preferably 1 to 3, and more preferably around 2. This ratio is preferable because it enhances thermal stability and strength.

[0056] The molecular weight of the intervening phase is preferably between 100 and 1000. This is desirable because it enhances thermal stability and strength.

[0057] The polyimide resin preferably contains repeating units represented by the following chemical formula (1). [ka] (1) In chemical formula (1), R preferably contains the structure of biphenyl, triphenyl, or tetraphenyl. R' preferably has a structure containing at least one aromatic ring.

[0058] Furthermore, it is more preferable that the polyimide resin has the structural formula of (2) or (3) below. [ka] (2) [ka] (3)

[0059] Figure 7 is a schematic diagram of the magnetic wedge of this embodiment. As shown in Figure 7, magnetic wedges can be not only simple rectangular parallelepiped shapes (with a rectangular cross-section), but also various shapes such as trapezoidal, hexagonal, and convex cross-sections. The closer the magnetic wedge is positioned to the gap surface between the rotor and stator, the more efficient the rotating electric machine becomes. From this viewpoint, trapezoidal, convex, and hexagonal shapes are preferable to rectangular shapes.

[0060] Furthermore, from the perspective of "a shape that easily draws magnetic flux towards the magnetic wedge, which improves the efficiency of a rotating electric machine," trapezoidal and convex shapes are preferable to hexagonal shapes. On the other hand, from the perspective of ease of manufacture and high reliability in terms of mechanical and thermal properties as a material, the rectangular shape is the most preferable, followed by the trapezoidal and hexagonal shapes. In that sense, the trapezoidal shape is very preferable because it is easy to position close to the gap surface between the rotor and stator, the trapezoidal shape makes it easy to draw magnetic flux towards the magnetic wedge, and furthermore, it is easy to manufacture and the reliability in terms of mechanical and thermal properties as a material is high.

[0061] Regardless of the shape, the three axial directions that intersect each other orthogonally or perpendicularly are defined as the width direction, thickness direction, and longitudinal direction. The longitudinal direction of a magnetic wedge is the direction in which the length of the magnetic wedge is longer. For example, if the shape of the magnetic wedge in question is approximately a rectangular parallelepiped, the longitudinal direction of the magnetic wedge is determined to be the direction along the longest side of this approximately rectangular parallelepiped shape.

[0062] The thickness and width directions of a magnetic wedge are directions perpendicular to the longitudinal direction of the magnetic wedge. The thickness and width directions of a magnetic wedge can be distinguished as follows: If the magnetic wedge in question is installed inside a rotating electric machine, the magnetic wedge in question is removed from inside the rotating electric machine. Here, the direction of rotation of the rotating electric machine becomes the width direction of the magnetic wedge in question.

[0063] The thickness direction is perpendicular to the width direction. On the other hand, if the magnetic wedge in question is not installed inside a rotating electric machine, the width direction is the direction closest to the average orientation direction of the flattened magnetic metal particles at the center of the cross section perpendicular to the longitudinal direction. The thickness direction is perpendicular to the width direction. Note that the end face of the magnetic wedge in question should be avoided when using the cross section perpendicular to the longitudinal direction.

[0064] For such a cross-section, the target magnetic wedge is cut perpendicular to its longitudinal direction so that the cross-section has a length of at least one-tenth of the longitudinal length of the target magnetic wedge. Furthermore, as the center of the cross-section formed by the cut, for example, a region containing multiple flattened magnetic metal particles is used at the geometric center of the cross-section. Next, the cross-section formed by the cut in the target magnetic wedge is observed using an optical microscope, SEM, or TEM.

[0065] Subsequently, for each flattened magnetic metal particle observed in the cross-section formed by cutting, the rectangle with the smallest area among the rectangles circumscribing each flattened magnetic metal particle is considered, and the orientation direction of the longer side of that rectangle is measured as the orientation direction.

[0066] However, some flattened magnetic metal particles may have unclear outlines during observation, making evaluation difficult. In other words, there may be cases where the particle outline cannot be clearly identified through image analysis, and in such cases, the particles are excluded from observation.

[0067] Figure 8 is a schematic diagram of the magnetic wedge of this embodiment. In Figure 8, the magnetic wedge has at least a portion of a surface coating layer. Covering the surface of the magnetic wedge with a surface coating layer in this way is preferable because it allows it to have excellent magnetic properties, electrical properties (high electrical resistivity, etc.), and maintains excellent properties without degrading its strength after heat resistance testing or its efficiency as a rotating electric machine. Having a surface coating layer is preferable because it suppresses oxidation of the flattened magnetic metal particles and flattened magnetic metal surface particles contained in the magnetic wedge, and maintains excellent magnetic properties (saturation magnetization, coercivity, and permeability).

[0068] The magnetic wedge according to this embodiment may have a smooth or rough surface in contact with the surface coating layer. A rough surface in contact with the surface coating layer means that the surface has irregularities (a rough surface), that some of the flattened magnetic metal surface particles near the surface in contact with the surface coating layer are not oriented in the width direction, or that a portion of the length of the flattened magnetic metal surface particles is located outside the contour average line (i.e., on the surface coating layer side).

[0069] Figure 9 is another schematic diagram of the magnetic wedge of this embodiment. In Figure 9, some of the flattened magnetic metal particles contained in the magnetic wedge have portions that protrude outward from the magnetic wedge. The figure shows the flattened magnetic metal particles located near the contour line in the width direction in a cross-section perpendicular to the longitudinal direction of the magnetic wedge and at the center of the longitudinal direction (hereinafter, the characteristics will be defined with respect to this cross-section). Note that the method for determining the cross-section perpendicular to the longitudinal direction of the magnetic wedge and at the center of the longitudinal direction is not limited as long as the size and contour line of the flattened magnetic metal particles can be determined. For example, observation can be performed using a scanning electron microscope (SEM), optical microscope, or transmission electron microscope (TEM), and observation can be performed at any magnification. Here, the flattened magnetic metal particles located closest to the contour line in the width direction are referred to as flattened magnetic metal surface particles. The average contour line in the width direction is an average line obtained by averaging the unevenness of the contour line in the width direction. The contour average line can be defined, for example, as the "average line" in surface roughness measurement, as defined in JIS-B0601 (ISO-4287).

[0070] In the magnetic wedge of this embodiment, it is preferable that the flat magnetic metal surface particles include flat magnetic metal surface particles in which 10% or more of the length of the flat magnetic metal particles are located outside the average contour line in the width direction. More preferably, it is preferable that 1% to 90% of the total number of flat magnetic metal surface particles present in the measured cross-section are flat magnetic metal surface particles in which 10% or more of the length of the flat magnetic metal surface particles are located outside the average contour line in the width direction of the magnetic wedge, more preferably 5% to 60%, and even more preferably 5% to 30%.

[0071] The orientation angle of the flattened magnetic metal surface particles, where 10% or more of their length is positioned outside the average contour line in the width direction of the magnetic wedge, is preferably 1 degree or more and 60 degrees or less with respect to the average contour line in the width direction, more preferably 3 degrees or more and 45 degrees or less, and even more preferably 3 degrees or more and 30 degrees or less.

[0072] Furthermore, the surface roughness Ra of the widthwise contour line of the magnetic wedge in Figures 8 and 9 is preferably 0.1 μm to 100 μm, more preferably 0.1 μm to 10 μm, and even more preferably 1 μm to 10 μm. It is preferable that the widthwise contour line (i.e., the widthwise surface) of the cross section perpendicular to the longitudinal direction of the magnetic wedge and at the center of the longitudinal direction satisfies this range of surface roughness, more preferably that the surface of the magnetic wedge including the widthwise and lengthwise directions satisfies this range of surface roughness, and even more preferably that any surface of the magnetic wedge satisfies this range of surface roughness. The surface roughness Ra and its measurement method are defined in JIS-B0601 (ISO-4287).

[0073] When a magnetic wedge has a portion of its surface in which flattened magnetic metal particles protrude outwards, the thickness of the surface coating layer is preferably equal to or greater than the average thickness of the flattened magnetic metal surface particles, and more preferably equal to or greater than the average length of the flattened magnetic metal particles. Even more preferably equal to or greater than the maximum length of the flattened magnetic metal particles. Having the above structure is preferable because the surface coating layer adheres firmly to (bonds to) the magnetic wedge (anchoring effect), protecting the magnetic wedge. This improves the reliability of the material, which is preferable. For example, it is preferable because the electrical resistivity can be greatly improved, so when used as a magnetic wedge, electrical short circuits can be suppressed, and eddy current losses can be reduced, improving the efficiency of the rotating electric machine. It is also preferable because it can maintain excellent properties without degrading the strength after heat resistance testing or the efficiency as a rotating electric machine. Furthermore, it is preferable because oxidation of the flattened magnetic metal particles and flattened magnetic metal surface particles can be suppressed, and excellent magnetic properties (saturation magnetization, coercivity, and permeability) can be maintained. Furthermore, having the above-described structure (arrangement structure of flat magnetic metal surface particles, number ratio, orientation angle, surface roughness, etc.) allows for efficient guidance of magnetic flux in a rotating electric machine, improving permeability and the efficiency of the rotating electric machine, which is preferable. Regarding permeability, it is preferable because the permeability is improved in the direction intermediate between the width direction and the thickness direction of the magnetic wedge. In addition, it is preferable that losses are also reduced in the direction intermediate between the width direction and the thickness direction of the magnetic wedge.

[0074] The surface coating layer preferably contains inorganic materials such as oxides, carbides, nitrides, and borides, or organic materials such as resins, but it is more preferable that it contains resins.

[0075] The resins 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, or copolymers thereof.

[0076] In particular, to achieve high thermal stability, the surface coating layer preferably contains a highly heat-resistant silicone resin, polyimide resin, imide resin, or bismaleimide resin. Epoxy resins, phenolic resins, and polyester resins are preferred because they are relatively heat-resistant, high-strength, and versatile resins.

[0077] Furthermore, the surface coating layer preferably contains at least one resin selected from the group consisting of bismaleimide resins, polyimide resins, polyester resins, phenolic resins, epoxy resins, and silicone resins.

[0078] Furthermore, as mentioned above, the type of resin can be identified by IR, NMR, etc. It is also preferable that the surface coating layer is a resin whose weight increase rate after exposure to air at room temperature for one week following exposure to air at 120°C for 30 minutes is 1% or less, and more preferably 0.1% or less. Additionally, it is preferable that the water absorption rate, as defined in ISO 62:1999 (JIS K7209:2000), is 1% or less, and more preferably 0.1% or less.

[0079] In magnetic wedges consisting of flattened magnetic metal particles and an intervening phase, preliminary investigations have revealed that, particularly when the intervening phase is resin, absorption of moisture or humidity increases weight and easily degrades mechanical properties such as strength, as well as thermomechanical properties. Furthermore, absorption of moisture or humidity by the flattened magnetic metal particles leads to oxidation, which is undesirable as it reduces saturation magnetization and permeability, and increases losses. Therefore, it is considered effective to minimize contact between the intervening phase and moisture (to suppress weight increase).

[0080] From the above, in this embodiment, by coating the surface of the magnetic wedge with a surface coating layer that has low water absorption and hygroscopic properties, it is possible to prevent moisture and humidity from coming into contact with the intervening phase as much as possible. For this reason, as mentioned above, it is preferable that the surface coating layer is a resin whose weight increase rate after exposure to air at room temperature for one week after exposure to air at 120°C for 30 minutes is 1% or less, and more preferably 0.1% or less. Furthermore, it is preferable that the water absorption rate as defined in ISO 62:1999 (JIS K7209:2000) is 1% or less, and more preferably 0.1% or less. More preferably, the surface coating layer contains at least one resin selected from the group consisting of bismaleimide resins, polyimide resins, polyester resins, phenolic resins, epoxy resins, and silicone resins, and is a resin whose weight increase rate after exposure to air at room temperature for one week following exposure at 120°C for 30 minutes is 1% or less, and is a resin whose water absorption rate as defined in ISO 62:1999 (JIS K7209:2000) is 1% or less. Even more preferably, the surface coating layer contains at least one resin selected from the group consisting of bismaleimide resins, polyimide resins, polyester resins, phenolic resins, epoxy resins, and silicone resins, and is a resin whose weight increase rate after exposure to air at room temperature for one week following exposure at 120°C for 30 minutes is 0.1% or less, and is a resin whose water absorption rate as defined in ISO 62:1999 (JIS K7209:2000) is 0.1% or less. By forming the surface coating layer described above, excellent properties can be maintained without degrading mechanical properties such as strength, or thermomechanical properties. Furthermore, oxidation of the flat magnetic metal particles is suppressed, thus maintaining excellent properties without degrading saturation magnetization, permeability, or losses.

[0081] A method for manufacturing the magnetic wedge of this embodiment will now be described. Note that the manufacturing method is not particularly limited and is described merely as an example.

[0082] The first step is to manufacture a magnetic metal ribbon containing at least one first element selected from the group consisting of Fe, Co, and Ni. This step involves manufacturing a ribbon or thin film using a film deposition apparatus such as a roll quenching apparatus or a sputtering apparatus. In this case, it is desirable to deposit a film with uniaxial anisotropy within the film surface by means of magnetic field deposition or rotational deposition when using a film deposition apparatus.

[0083] The second step is to heat-treat the magnetic metal ribbon at a temperature of 50°C to 800°C. 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 (hydrogen), CO (carbon monoxide), or CH4 (methane). More preferably, the heat treatment is performed in a magnetic field.

[0084] The third step involves crushing the heat-treated magnetic metal ribbon to produce flattened magnetic metal particles. In this step, crushing is carried out using a crushing device such as a bead mill or a planetary mill. The type of crushing device is not particularly limited. Examples include planetary mills, bead mills, rotary ball mills, vibrating ball mills, agitated ball mills (attritors), jet mills, centrifugal separators, or methods combining milling and centrifugal separation.

[0085] In the third step, the thickness of the flat magnetic metal particles can be reduced not only by simple crushing but also by combining it with rolling. If the desired thickness has been achieved by the second step, the rolling process can be omitted. Rolling can be performed simultaneously, after crushing, or after rolling. In this case, a device that can apply a strong gravitational acceleration is preferable, but this can be done using, for example, a planetary mill, bead mill, rotary ball mill, vibrating ball mill, agitated ball mill (attritor), jet mill, centrifuge, or a method that combines a mill and centrifuge.

[0086] The above cutting, crushing, and rolling processes are carried out (rolling is performed as needed; it is omitted if unnecessary). In some cases, it is desirable to repeat the cutting, crushing, and rolling processes until flattened magnetic metal particles of the specified thickness and aspect ratio are obtained.

[0087] Furthermore, it is desirable to remove lattice strain from the obtained flattened magnetic metal particles by heat treatment. This heat treatment is preferably carried out at a temperature of 50°C to 800°C, similar to the second step, and the atmosphere for the heat treatment 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, CO, or CH4. Moreover, it is even more desirable to carry out the heat treatment in a magnetic field.

[0088] Next, in the fourth step, the intervening phase and magnetic metal particles are mixed to form a mixed powder of the intervening phase and flattened magnetic metal particles. Next, in the fifth step, the mixed powder of the intervening phase and magnetic metal particles is molded. Heat treatment may also be performed before or after the above steps as appropriate. That is, 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. Furthermore, it is more desirable to perform the heat treatment in a magnetic field.

[0089] In the fifth step, it is preferable to use a method that applies press pressure in a uniaxial direction, such as uniaxial press molding or hot press molding. When press pressure is applied in a uniaxial direction, the flat magnetic metal particles tend to stack and orient in the direction in which the press pressure is applied. Therefore, with simple uniaxial press molding, the flat magnetic metal particles will stack and orient in one direction, in the direction in which the press pressure is applied, which is not desirable. For this reason, when applying press pressure in a uniaxial direction, it is preferable to apply a magnetic field in a direction parallel to the direction in which the press pressure is applied. It is also preferable to magnetize the mold punch during molding in a direction parallel to the direction in which the press pressure is applied. These measures make it easier for the flat magnetic metal particles to move in a direction parallel to the direction in which the press pressure is applied. Furthermore, it is preferable to perform hot press molding after uniaxial press molding. If the intervening phase is, for example, a thermosetting resin, it is preferable to adjust the hot press temperature and time during hot press molding and stop before the intervening phase hardens. In addition, it is more preferable to perform hot press molding while applying a magnetic field in a direction parallel to the direction in which the press pressure is applied.

[0090] Furthermore, it is preferable to reduce or release the press pressure when the resin is softening or melting during hot pressing. The hot pressing temperature is preferably 50°C to 1000°C, and more preferably 50°C to 800°C. The applied magnetic field is preferably as large as possible, but it is preferably 1 kOe or more, and more preferably 10 kOe or more. The press pressure is preferably 1 MPa to 100 MPa, and more preferably 1 MPa to 10 MPa.

[0091] Subsequently, it is preferable to perform heat treatment while applying a magnetic field parallel to the direction in which the press pressure is applied, in order to completely harden the material. The heat treatment temperature is preferably between 50°C and 1000°C, and more preferably between 50°C and 800°C. The larger the applied magnetic field, the better, but it is preferable to apply 1 kOe or more, and more preferably 10 kOe or more.

[0092] Here, the ratio of "flat magnetic metal surface particles in which 10% or more of the length is located outside the average contour line in the width direction of the magnetic wedge" to the total number of flat magnetic metal surface particles can be adjusted by adjusting the hot press temperature and time. For example, if you want to increase the ratio of "flat magnetic metal surface particles in which 10% or more of the length is located outside the average contour line in the width direction of the magnetic wedge" to the total number of flat magnetic metal surface particles, you can adjust this by lowering the hot press temperature or shortening the hot press time. Conversely, if you want to decrease the ratio of "flat magnetic metal surface particles in which 10% or more of the length is located outside the average contour line in the width direction of the magnetic wedge" to the total number of flat magnetic metal surface particles, you can adjust this by raising the hot press temperature or lengthening the hot press time. It should be noted that even if the intervening phase is a thermoplastic resin or an oxide with a softening point, it is possible to manufacture similar magnetic wedges by devising the molding process. In other words, it is possible to manufacture similar magnetic wedges regardless of the type of intervening phase. For example, during hot pressing, when the resin is softening or melting, it is possible to reduce or release the press pressure, or to apply a magnetic field parallel to the direction of the applied press pressure, and then lower the temperature to solidify the resin, thereby producing a similar magnetic wedge.

[0093] Next, in the sixth step, a surface coating layer is formed on the surface of the molded magnetic wedge. In this step, an inorganic or organic material is coated onto the surface of the magnetic wedge. The method of coating is not particularly limited. When coating with an organic material such as resin, it is preferable to coat it by impregnation, dipping, etc., or, in some cases, to press it down with a hot press after coating. When coating with an inorganic material, it is preferable to coat it by gas phase method, liquid phase method such as sol-gel, etc., or, in some cases, to press it down with a hot press after coating. It is also preferable to perform heat treatment after coating to form a strong coating layer.

[0094] When measuring the coercivity with respect to direction in a plane parallel to the flattened plane of the flattened magnetic metal particles of a magnetic wedge, for example, the coercivity is measured by changing the direction every 22.5 degrees for a 360-degree angle within the plane.

[0095] Having a difference in coercivity within the plane of the magnetic wedge is preferable because it reduces the minimum coercivity value compared to the isotropic case where there is almost no difference in coercivity. In materials that have magnetic anisotropy within a plane, there is a difference in coercivity depending on the direction within the plane, and the minimum coercivity value is smaller compared to magnetically isotropic materials. This reduces hysteresis loss and improves permeability, which is preferable.

[0096] In a plane parallel to the flattened plane of the flattened magnetic metal particles of the magnetic wedge, the larger the ratio of the coercivity difference depending on the direction, the more preferable it is, preferably 1% or more. More preferably, the ratio of the coercivity difference is 10% or more, even more preferably 50% or more, and even more preferably 100% or more. The ratio of the coercivity difference referred to here is defined as (Hc(max)-Hc(min)) / Hc(min)×100(%), using the maximum coercivity Hc(max) and the minimum coercivity Hc(min) within the flattened plane.

[0097] Furthermore, coercivity can be easily evaluated using a vibrating sample magnetometer (VSM) or the like. If the coercivity is low, it can be measured even below 0.1 Oe by using a low-field unit. The measurement is performed by changing the direction of the magnetic wedge within the aforementioned plane (a plane parallel to the flattened plane of the flattened magnetic metal particle) with respect to the direction of the measurement magnetic field.

[0098] When calculating coercivity, the difference between the magnetic fields at two points where the horizontal axis intersects (magnetic fields H1 and H2 where magnetization is zero) can be divided by 2 (i.e., coercivity can be calculated as |H2-H1| / 2).

[0099] As described above, according to this embodiment, the magnetic wedge is a magnetic wedge for a rotating electric machine, and the magnetic wedge comprises a plurality of flattened magnetic metal particles and an intervening phase, and a surface coating layer exists on at least a part of the surface of the magnetic wedge. This makes it possible to provide a magnetic wedge with excellent electrical properties and excellent heat resistance (electrical properties, magnetic properties, mechanical properties). Furthermore, it is even more preferable if the magnetic wedge has flattened magnetic metal particles and the flattened magnetic metal particles have the aforementioned structure (arrangement structure of flattened magnetic metal surface particles, number ratio, orientation angle, surface roughness, etc.), as this allows for efficient guidance of magnetic flux in the rotating electric machine, improving permeability and the efficiency of the rotating electric machine. In addition, by having flattened magnetic metal particles with the above structure, the surface coating layer can be firmly formed (anchoring effect), further improving the reliability of the material and achieving even better heat resistance (electrical properties, magnetic properties, mechanical properties), which is preferable.

[0100] (Second Embodiment) The rotating electric machine of this embodiment is equipped with the magnetic wedge of the first embodiment. Therefore, descriptions that overlap with the first embodiment are omitted. In this specification, the term "rotating electric machine" refers to a concept that includes electric motors, generators, and motor-generators that perform both motor and generator functions as needed.

[0101] Figure 10 shows an example of a radial gap motor according to this embodiment. A radial gap motor has a rotor and a stator that is positioned opposite the rotor with a predetermined radial gap. In Figure 10, the rotor is positioned inside the stator, but it may also be positioned outside. The rotor has a rotor core and a shaft and is supported so that it can rotate. The stator, on the other hand, has a stator core, field coils inserted into slots in the stator core, and magnetic wedges held in wedge grooves in the slot openings. Figure 10 shows an example of the arrangement of magnetic wedges according to the first embodiment, but is not limited to this. In the case of a radial gap rotating electric machine, since the stator is positioned opposite the rotor with a predetermined radial gap, the "gap surface" is a surface parallel to the cylindrical surface centered on the rotor's axis of rotation. Therefore, the radial direction is perpendicular to the gap surface, and the axial direction and rotational direction are parallel to the gap surface. Figure 10 shows flattened magnetic metal particles 10, intervening phase 20, magnetic wedge 100, rotating electric machine 200, rotor 210, stator 220, coil 230, air gap surface 240, and iron core teeth 250.

[0102] By arranging the magnetic wedge of the first embodiment, it becomes possible to reduce harmonic losses occurring on the rotor surface while suppressing leakage flux. In addition, the torque of the radial gap type motor is increased because the magnetic flux passing through the air gap increases. High efficiency can be achieved through either or both of the above loss reduction effect and torque increase effect.

[0103] Furthermore, radial gap motors can be any of the following: those with a conductor in the rotor (induction motor), those with a permanent magnet (permanent magnet motor), or those with a magnetic material (reluctance motor).

[0104] Figure 11 shows an example of an axial gap motor according to this embodiment. The axial gap motor has a rotor and a stator that is positioned opposite the rotor with a predetermined gap in the axial direction. The stator includes a stator core, field coils inserted into slots in the stator core, and magnetic wedges held in wedge grooves in the slot openings. By arranging the magnetic wedges in this embodiment, it is possible to reduce harmonic losses occurring on the rotor surface while suppressing the increase in leakage flux. In addition, the torque of the axial gap motor is increased because the magnetic flux passing through the gap increases. As a result, high efficiency can be achieved. In Figure 11, the rotor is positioned between two stators, but it may also be positioned on one side or both sides of a single stator. In the case of an axial gap rotating electric machine, since the stators are positioned opposite the rotor with a predetermined gap in the axial direction, the "gap surface" is a surface perpendicular to the rotor's rotation axis. Therefore, the axial direction is perpendicular to the gap surface, and the rotational and radial directions are parallel to the gap surface. Figure 12 shows the flattened magnetic metal particles 10, the intervening phase 20, the magnetic wedge 100, the rotating electric machine 200, the rotor 210, the coil 230, the gap surface 240, the iron core teeth 250, the stator 270, and the shaft 280.

[0105] Figure 12 is a schematic diagram showing an example of a generator according to this embodiment. The generator typically has a rotor in which excitation coils are housed in slots of the rotor core (in addition, a rotor using permanent magnets as an excitation source may be used), and a stator in which armature coils are housed in slots of the stator core. By rotating the rotor and passing an excitation current through the excitation coils, power is generated in the armature coils. The rotor comprises a rotor core, field coils inserted into slots of the rotor core, and magnetic wedges held in wedge grooves of the slot openings, and is supported by bearings so that it can rotate. By arranging the magnetic wedges in this embodiment, it is possible to reduce harmonic losses occurring on the surface of the stator while suppressing the increase in leakage flux. In addition, since the magnetic flux passing through the air gap and linking with the armature coils increases, the generated voltage induced in the armature coils increases. As a result, high efficiency can be achieved. In Figure 12, the magnetic wedge is positioned in the slot opening of the rotor core, but it may also be positioned in the slot opening of the stator core. Also, although the figure shows a wound-type generator with an excitation coil on the rotor, it may also be a permanent magnet type generator with a permanent magnet on the rotor. In this case, the magnetic wedge is positioned in the slot opening of the stator core. Figure 12 shows flat magnetic metal particles 10, intervening phase 20, magnetic wedge 100, rotating electric machine 200, rotor 210, stator core 222, excitation coil 232, armature coil 234, air gap surface 240, and core teeth 250.

[0106] Since a linear motor is a radial gap type motor unfolded into a flat plate structure, the magnetic wedge of the present invention can also be applied to a linear motor. That is, the stator comprises a stator core and field coils inserted into slots in the stator core, and a magnetic wedge may be provided at the slot opening. Figure 13 is a schematic diagram showing an example of a linear motor of this embodiment. In a linear motor, the direction of travel of the movable element, the direction perpendicular to the direction of travel of the movable element, and the direction perpendicular to the stator correspond to the rotational direction, axial direction, and radial direction of the radial gap type motor, respectively. By arranging the magnetic wedge of this embodiment, it is possible to reduce harmonic losses occurring on the surface of the movable element while suppressing the increase in leakage flux. In addition, since the magnetic flux passing through the air gap increases, the thrust of the linear motor is improved. As a result, high efficiency can be achieved. Figure 13 shows the flattened magnetic metal particles 10, the intervening phase 20, the magnetic wedge 100, the stator 220, the coil 230, the gap surface 240, the iron core teeth 250, and the movable element 290.

[0107] 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 mitigate the pulsation of the magnetic flux distribution on the surface of the iron core, thereby achieving high efficiency. The slot shape of the rotating electric machine of this embodiment may be a semi-closed slot, but it is preferably an open slot. This is preferable because it can significantly reduce harmonic losses.

[0108] 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 blowers; energy systems such as thermal power generators, hydroelectric power generators, wind power generators, nuclear power generators, and geothermal power generators; and home appliances such as washing machines, thereby improving the efficiency of the system. In particular, for large-capacity industrial machines, open slots are generally used for the slot shape, so it is preferable to provide the magnetic wedge of the first embodiment. Also, for main motors for railways, type-wound coils are used due to the need to withstand high voltage and vibration, and open slots are adopted for the slot shape, so it is preferable to provide the magnetic wedge of the first embodiment.

[0109] In railways, losses in rotating electric machinery account for approximately half of the power consumption during train operation, so reducing losses in rotating electric machinery has a significant effect on improving efficiency. Furthermore, in electric vehicles and hybrid cars, using the magnetic wedge of the first embodiment can improve the efficiency of the main motor, thereby extending the driving range.

[0110] In the field of power generation, significant improvements are expected for hydroelectric generators, particularly variable-speed pumped-storage generators. Significant improvements are also expected for wind turbines.

[0111] (Examples) Examples 1 to 15 are described in more detail below, in comparison with Comparative Example 1.

[0112] (Example 1) First, a ribbon of Fe-Co-Si-B (Fe70Co30B25(at%)-4wt%Si) was prepared using a single-roll quenching device. Next, the obtained ribbon was heat-treated at 300°C in an H2 atmosphere. Then, this ribbon was crushed using a mixer device to obtain flattened magnetic metal particles (average thickness was approximately 15 μm, and the average ratio of the average length within the flattened plane to the thickness was approximately 30). Subsequently, the obtained flattened magnetic metal particles were mixed with a polyester resin and molded. After that, hot-press molding was performed and the resin was completely cured to produce a magnetic wedge. At this time, there were no flattened magnetic metal surface particles where more than 10% of the length was located outside the average contour line in the width direction of the magnetic wedge. Finally, a polyester resin was coated as a surface coating layer. Furthermore, it was confirmed that the thickness of the surface coating layer is equal to or greater than the average thickness of the flat magnetic metal surface particles, that the weight increase rate of the surface coating layer after exposure to air at 120°C for 30 minutes followed by exposure to air at room temperature for one week is 1% or less, and that the water absorption rate as defined in ISO 62:1999 (JIS K7209:2000) is 1% or less.

[0113] (Example 2) This example is almost identical to Example 1, except that the surface coating layer is made of a bismaleimide-based resin.

[0114] (Example 3) The method is almost identical to Example 1, except that the surface coating layer is made of a polyimide-based resin.

[0115] (Example 4) The method is almost identical to Example 1, except that the type of surface coating layer used is a phenolic resin.

[0116] (Example 5) This example is almost identical to Example 1, except that the surface coating layer is made of epoxy resin.

[0117] (Example 6) The only difference from Example 1 is that the surface coating layer is made of a silicone-based resin.

[0118] (Example 7) In Example 1, when mixing flat magnetic metal particles with a polyester resin and molding (applying press pressure in a uniaxial direction), a magnetic field was applied in a direction parallel to the direction of press pressure application. Then, hot press molding was performed. During hot press molding, the hot press temperature and time were adjusted and stopped before hardening. After that, heat treatment was performed while applying a magnetic field in a direction parallel to the direction of press pressure application to fully harden and produce a magnetic wedge. By adjusting the hot press temperature and time, the ratio of flat magnetic metal surface particles in which 10% or more of the length is located outside the average contour line in the width direction of the magnetic wedge was adjusted to the total number of flat magnetic metal surface particles (in Example 7, this was 30%). After that, a polyester resin was applied as a surface coating layer. Furthermore, it was confirmed that the thickness of the surface coating layer is equal to or greater than the average thickness of the flat magnetic metal surface particles, that the weight increase rate of the surface coating layer after exposure to air at 120°C for 30 minutes followed by exposure to air at room temperature for one week is 1% or less, and that the water absorption rate as defined in ISO 62:1999 (JIS K7209:2000) is 1% or less.

[0119] (Example 8) The method is almost identical to Example 7, except that the surface coating layer is made of a bismaleimide-based resin.

[0120] (Example 9) This example is almost identical to Example 7, except that the surface coating layer is made of a polyimide-based resin.

[0121] (Example 10) The only difference from Example 7 is that the surface coating layer is made of a phenolic resin.

[0122] (Example 11) The only difference from Example 7 is that the surface coating layer is made of epoxy resin.

[0123] (Example 12) The only difference from Example 7 is that the surface coating layer is made of a silicone-based resin.

[0124] (Example 13) This example is almost identical to Example 7, except that by adjusting the hot press temperature and time, the ratio of flat magnetic metal surface particles in which more than 10% of the length is located outside the average contour line in the width direction of the magnetic wedge, relative to the total number of flat magnetic metal surface particles, was set to 1%.

[0125] (Example 14) This example is almost identical to Example 7, except that by adjusting the hot press temperature and time, the proportion of flat magnetic metal surface particles in which more than 10% of the length is located outside the average contour line in the width direction of the magnetic wedge was set to 90% of the total number of flat magnetic metal surface particles.

[0126] (Example 15) This example is almost identical to Example 7, except that by adjusting the hot press temperature and time, the proportion of flat magnetic metal surface particles in which more than 10% of the length is located outside the average contour line in the width direction of the magnetic wedge was set to 95% of the total number of flat magnetic metal surface particles.

[0127] (Comparative Example 1) This is almost the same as Example 1, except that a surface coating layer of the polyester resin is not formed.

[0128] Table 1 shows, for each of the magnetic wedges of this embodiment (Examples 1 to 15), the presence or absence of a surface coating layer, the type of surface coating layer (only for cases with a surface coating layer), and the ratio of flattened magnetic metal surface particles in which 10% or more of the length is located outside the average contour line in the width direction of the magnetic wedge, to the total number of flattened magnetic metal surface particles, along with Comparative Example 1.

[0129] Table 2 shows the electrical resistivity, electrical resistivity after heat resistance testing, magnetic permeability, and strength of the magnetic wedges of this embodiment (Examples 1 to 15), along with Comparative Example 1.

[0130] (1) Electrical resistivity: The DC electrical resistivity of the surface in the length and width directions of the magnetic wedge is measured and expressed as a ratio to the DC electrical resistivity of the sample of Comparative Example 1 (= DC electrical resistivity of the evaluation sample / DC electrical resistivity of Comparative Example 1).

[0131] (2) Electrical resistivity after heat resistance test: For the evaluation sample, the DC electrical resistivity (DC electrical resistivity on the surface in the length and width directions of the magnetic wedge) after heating at 180°C in air for 100 hours (heat resistance test) is measured and shown as a ratio with the DC electrical resistivity of the sample of Comparative Example 1 (= DC electrical resistivity of the evaluation sample after heating at 180°C in air for 100 hours / DC electrical resistivity of Comparative Example 1 after heating at 180°C in air for 100 hours).

[0132] (3) Permeability after heat resistance test: For the evaluation sample, the permeability (permeability at 100 Hz in the direction midway between the width and thickness directions of the magnetic wedge) after heating at 180°C in air for 100 hours (heat resistance test) is measured and shown as a ratio with the permeability of the sample of Comparative Example 1 after heating at 180°C in air for 100 hours (= permeability of the evaluation sample after heating at 180°C in air for 100 hours / permeability of Comparative Example 1 after heating at 180°C in air for 100 hours).

[0133] (4) Strength after heat resistance test: For the evaluation sample, the flexural strength was measured at 25°C after heating in air at 180°C for 100 hours (heat resistance test), and the strength is shown as a ratio with the flexural strength of the sample of Comparative Example 1 at 25°C after heating in air at 180°C for 100 hours (= flexural strength of the evaluation sample at 25°C after heating in air at 180°C for 100 hours / flexural strength of Comparative Example 1 at 25°C after heating in air at 180°C for 100 hours).

[0134] [Table 1]

[0135] [Table 2]

[0136] Table 2 shows that Examples 1-6 exhibit superior properties compared to Comparative Example 1 in terms of electrical resistivity, electrical resistivity after heat resistance testing, magnetic permeability, and strength. This is because forming an insulating surface coating layer not only increases the electrical resistivity of the magnetic wedge surface but also protects the magnetic wedge during heat resistance testing. As a result, it was found that excellent properties can be maintained without deterioration of electrical resistivity, magnetic permeability, and strength after heat resistance testing. Furthermore, this effect becomes more pronounced when, in the magnetic wedge, flattened magnetic metal surface particles whose length exceeds 10% and are located outside the average contour line in the width direction of the magnetic wedge account for 1% to 90% of the total number of flattened magnetic metal surface particles. In Examples 7 to 14, the proportion of flattened magnetic metal surface particles in which 10% or more of the length is located outside the average contour line in the width direction of the magnetic wedge is between 1% and 90% of the total number of flattened magnetic metal surface particles. This shows that higher performance is achieved compared to the 0% in Examples 1 to 6 and the 95% in Example 15. In other words, it was found that the presence of "flattened magnetic metal surface particles in which 10% or more of the length is located outside the average contour line in the width direction of the magnetic wedge, comprising between 1% and 90% of the total number of flattened magnetic metal surface particles" results in superior electrical resistivity, permeability, and strength after the heat resistance test. In summary, forming a surface coating layer increases electrical resistivity, and also improves electrical resistivity, magnetic permeability, and strength after heat resistance testing. However, this effect is particularly pronounced when "1% to 90% of the total number of flattened magnetic metal surface particles are located outside the average contour line in the width direction of the magnetic wedge, with 10% or more of their length being outside the average contour line in the width direction of the magnetic wedge."

[0137] While several embodiments and examples of the present invention have been described, these embodiments and examples are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out 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 variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents.

[0138] Furthermore, the above embodiments can be summarized in the following technical proposal. (Technical proposal 1) A magnetic wedge for a rotating electric machine, wherein the magnetic wedge comprises a plurality of flattened magnetic metal particles and an intervening phase. A magnetic wedge having a surface coating layer on at least a portion of its surface. (Technical proposal 2) The magnetic wedge according to Technical Proposal 1, wherein the thickness of the surface coating layer is equal to or greater than the average thickness of the flat magnetic metal surface particles. (Technical proposal 3) A magnetic wedge according to Technical Proposal 1 or Technical Proposal 2, wherein the surface coating layer contains resin. (Technical proposal 4) A magnetic wedge according to any one of Technical Proposals 1 to 3, wherein the surface coating layer is made of a resin whose weight increase rate after exposure to air at room temperature for one week following exposure to air at 120°C for 30 minutes is 1% or less. (Technical proposal 5) A magnetic wedge according to any one of Technical Proposals 1 to 4, wherein the surface coating layer has a water absorption rate of 1% or less as defined in ISO 62:1999 (JIS K7209:2000). (Technical proposal 6) A magnetic wedge according to any one of Technical Proposals 1 to 5, wherein the surface coating layer comprises at least one resin selected from the group consisting of bismaleimide resin, polyimide resin, polyester resin, phenolic resin, epoxy resin, and silicone resin. (Technical proposal 7) In a cross-section perpendicular to the longitudinal direction of the magnetic wedge and at the center in the longitudinal direction, A magnetic wedge according to any one of Technical Proposals 1 to 6, comprising flat magnetic metal surface particles among the plurality of flat magnetic metal particles, wherein 10% or more of the length of the flat magnetic metal particles is positioned outside the average contour line in the width direction of the magnetic wedge. (Technical proposal 8) A magnetic wedge according to any one of Technical Proposals 1 to 7, wherein, in a cross-section perpendicular to the longitudinal direction of the magnetic wedge and at the center of the longitudinal direction, 10% or more of the length of the flat magnetic metal surface particles is located outside the average contour line in the width direction of the magnetic wedge, and these particles constitute 1% to 90% of the total number of flat magnetic metal surface particles. (Technical proposal 9) A magnetic wedge according to any one of Technical Proposals 1 to 8, wherein, in a cross-section perpendicular to the longitudinal direction of the magnetic wedge and at the center of the longitudinal direction, 10% or more of the length of the flat magnetic metal surface particles is arranged outside the average contour line in the width direction of the magnetic wedge, and the orientation angle of these flat magnetic metal surface particles is 1 degree or more and 60 degrees or less with respect to the average contour line in the width direction. (Technical proposal 10) A magnetic wedge according to any one of Technical Proposals 1 to 9, wherein the surface roughness Ra of the contour line in the width direction in a cross section perpendicular to the longitudinal direction of the magnetic wedge and at the center of the longitudinal direction is 0.1 μm or more and 100 μm or less. (Technical proposal 11) The magnetic wedge according to any one of the technical proposals 1 to 10, wherein the intervening phase is present between the plurality of flattened magnetic metal particles and includes at least one second element selected from the group consisting of oxygen (O), carbon (C), nitrogen (N), and fluorine (F). (Technical proposal 12) A magnetic wedge according to any one of Technical Proposals 1 to 11, wherein the intervening phase includes a resin. (Technical proposal 13) The magnetic wedge according to any one of Technical Proposals 1 to 12, wherein the intervening phase comprises at least one resin selected from the group consisting of bismaleimide resins, polyimide resins, polyester resins, phenolic resins, epoxy resins, and silicone resins. (Technical proposal 14) A magnetic wedge according to any one of Technical Proposals 1 to 13, wherein the plurality of flattened magnetic metal particles have an average thickness of 10 nm to 100 μm, and have 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 in the flattened plane to the thickness is 5 to 10000. (Technical proposal 15) A magnetic wedge according to any one of Technical Proposals 1 to 14, wherein at least a portion of the surface of the flattened magnetic metal particle is covered with a coating layer having a thickness of 0.1 nm to 1 μm and containing at least one second element selected from the group consisting of oxygen (O), carbon (C), nitrogen (N), and fluorine (F). (Technical proposal 16) A magnetic wedge according to any one of Technical Proposals 1 to 15, having a difference in coercivity depending on the direction within the flattened plane of the flattened magnetic metal particles. (Technical proposal 17) A magnetic wedge according to any one of Technical Proposals 1 to 16, having a difference in coercivity depending on the direction in a plane parallel to the aforementioned flattened plane. (Technical proposal 18) A rotating electric machine equipped with the magnetic wedge described in any one of Technical Proposal 1 to Technical Proposal 17. [Explanation of symbols]

[0139] 6: flat surface 9: Covering layer 10: Flat magnetic metal particles 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 :Void surface 250: Iron Core Teeth 260: Iron Core Slot 270: Stator 280: Axis 290: Mover

Claims

1. A magnetic wedge for a rotating electric machine, wherein the magnetic wedge comprises a plurality of flattened magnetic metal particles, a plurality of flattened magnetic metal surface particles perpendicular to the longitudinal direction of the magnetic wedge and closest to the widthwise contour line in a cross section at the center of the longitudinal direction, and an intervening phase, wherein a surface coating layer is present on at least a portion of the surface of the magnetic wedge, and the thickness of the surface coating layer is equal to or greater than the average thickness of the flattened magnetic metal surface particles.

2. The magnetic wedge according to claim 1, wherein the surface coating layer includes a resin.

3. The magnetic wedge according to claim 1, wherein the surface coating layer is a resin whose weight increase rate after exposure to air at room temperature for one week following exposure to air at 120°C for 30 minutes is 1% or less.

4. The magnetic wedge according to claim 1, wherein the surface coating layer has a water absorption rate of 1% or less as defined in ISO 62:1999 (JIS K7209:2000).

5. The magnetic wedge according to claim 1, wherein the surface coating layer comprises at least one resin selected from the group consisting of bismaleimide resin, polyimide resin, polyester resin, phenolic resin, epoxy resin, and silicone resin.

6. The magnetic wedge according to claim 1, wherein, in a cross-section perpendicular to the longitudinal direction of the magnetic wedge and at the center of the longitudinal direction, the plurality of flat magnetic metal particles include a flat magnetic metal surface particle in which 10% or more of the length of the flat magnetic metal particle is arranged outside the average contour line in the width direction of the magnetic wedge.

7. The magnetic wedge according to claim 1, wherein, in a cross-section perpendicular to the longitudinal direction of the magnetic wedge and at the center of the longitudinal direction, 10% or more of the length of the flattened magnetic metal surface particles is located outside the average contour line in the width direction of the magnetic wedge, and these particles constitute 1% to 90% of the total number of flattened magnetic metal surface particles.

8. The magnetic wedge according to claim 1, wherein, in a cross section perpendicular to the longitudinal direction of the magnetic wedge and at the center of the longitudinal direction, the orientation angle of flat magnetic metal surface particles such that 10% or more of the length is located outside the average contour line in the width direction of the magnetic wedge is 1 degree or more and 60 degrees or less with respect to the average contour line in the width direction.

9. The magnetic wedge according to claim 1, wherein the surface roughness Ra of the contour line in the width direction in a cross section perpendicular to the longitudinal direction of the magnetic wedge and at the center of the longitudinal direction is 0.1 μm or more and 100 μm or less.

10. The magnetic wedge according to claim 1, wherein the intervening phase is present between the plurality of flattened magnetic metal particles and comprises at least one second element selected from the group consisting of oxygen (O), carbon (C), nitrogen (N), and fluorine (F).

11. The magnetic wedge according to claim 1, wherein the intervening phase includes a resin.

12. The magnetic wedge according to claim 1, wherein the intervening phase comprises at least one resin selected from the group consisting of bismaleimide resins, polyimide resins, polyester resins, phenolic resins, epoxy resins, and silicone resins.

13. The magnetic wedge according to claim 1, wherein the plurality of flattened magnetic metal particles and the plurality of flattened magnetic metal surface particles have an average thickness of 10 nm or more and 100 μm or less, and have 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 in the flattened plane to the thickness is 5 or more and 10000 or less.

14. The magnetic wedge according to claim 1, wherein at least a portion of the surface of the flattened magnetic metal particle is covered with a coating layer having a thickness of 0.1 nm to 1 μm and containing at least one second element selected from the group consisting of oxygen (O), carbon (C), nitrogen (N), and fluorine (F).

15. The magnetic wedge according to claim 1, having a difference in coercivity depending on the direction within the flattened plane of the flattened magnetic metal particles.

16. The magnetic wedge according to claim 1, having a difference in coercivity depending on the direction in a plane parallel to the flattened plane.

17. A rotating electric machine comprising the magnetic wedge according to claim 1.

Images