Magnetic wedge and rotating electric machine

Abstract

To provide a magnetic wedge capable of improving both the efficiency and torque of a rotating electrical machine to a high level beyond the trade-off relationship in the magnetic wedge.SOLUTION: A magnetic wedge for a rotating electric machine according to the present invention includes a high magnetic permeability portion and a low magnetic permeability portion having relatively different magnetic permeability, the magnetic permeability of the low magnetic permeability portion is lower than the magnetic permeability of the high magnetic permeability portion, the high-permeability portion is positioned at the center of the magnetic wedge in the width direction, and the low-permeability portions are positioned at both ends of the magnetic wedge in the width direction.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a magnetic wedge used in a rotating electric machine, and to a rotating electric machine using the magnetic wedge. [Background technology]

[0002] In a typical radial gap type rotating electric machine, the stator (hereinafter referred to as stator) and rotor (hereinafter referred to as rotor) are arranged coaxially, and multiple teeth with coils wound around them are arranged at equal intervals in the circumferential direction on the stator around the rotor. Magnetic wedges may be arranged on the rotor-side tips of the teeth to connect the tips of adjacent teeth. In this case, unlike coil components, the magnetic wedges are used without winding a coil around them themselves.

[0003] By arranging such a magnetic wedge, it is possible to magnetically shield the magnetic flux reaching the coil from the rotor, and suppress the eddy current loss of the coil. In addition, by arranging the magnetic wedge, it is possible to smooth the magnetic flux distribution (especially the magnetic flux distribution in the circumferential direction) in the gap between the stator and rotor, which not only makes the rotor rotate smoothly, but also reduces the eddy current loss generated in the rotor. The advantage of such a magnetic wedge becomes more pronounced the higher the magnetic permeability of the magnetic wedge or the thicker the magnetic wedge is.

[0004] Patent Documents 1 and 2 disclose a magnetic wedge made of a laminate of electromagnetic steel sheets or a compact of ferromagnetic metal powder. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2007-221913 A [Patent Document 2] JP 2019-97258 A Summary of the Invention [Problem to be solved by the invention]

[0006] The presence of the magnetic wedge causes a side effect that part of the magnetic flux that should flow from the teeth to the rotor is short-circuited between the teeth via the magnetic wedge, reducing the magnetic flux flowing to the rotor and reducing the torque of the rotating electric machine. The higher the magnetic permeability of the magnetic wedge is, or the thicker the magnetic wedge is, the more pronounced this side effect becomes. In other words, the merits of the magnetic wedge (lower losses, i.e., higher efficiency) and the side effects (lower torque) are in a trade-off relationship, with the magnetic permeability or thickness of the magnetic wedge as a parameter. For this reason, with conventional magnetic wedges, the relative permeability is kept at around 3 to 5 to avoid excessive torque reduction, and efficiency is improved to a certain extent, but the effect is limited.

[0007] Therefore, the present invention provides a magnetic wedge that overcomes the above-mentioned trade-off relationship in the magnetic wedge and is capable of improving both the efficiency and torque of a rotating electric machine to a high level. [Means for solving the problem]

[0008] The magnetic wedge of the present invention is a magnetic wedge for a rotating electric machine, and has a high magnetic permeability portion and a low magnetic permeability portion having relatively different magnetic permeability from each other, the low magnetic permeability portion has a lower magnetic permeability than the high magnetic permeability portion, the high magnetic permeability portion is located in the center of the magnetic wedge in the width direction, and the low magnetic permeability portions are located on both ends of the magnetic wedge in the width direction. death, The high magnetic permeability portion includes soft magnetic particles and an electrically insulating material between the soft magnetic particles, the soft magnetic particles being a plurality of Fe-based soft magnetic alloy particles containing an element M which is more easily oxidized than Fe, and the high magnetic permeability portion includes the Fe-based soft magnetic alloy particles bound together by an oxide phase containing the element M, The low magnetic permeability portion contains an element M which is more easily oxidized than Fe, and is configured by binding a plurality of metal particles having a lower magnetic permeability than the Fe-based soft magnetic alloy particles with an oxide phase containing the element M. It is characterized by:

[0011] In the magnetic wedge, the element M is preferably at least one of Al, Si, Cr, Zr, and Hf.

[0012] In the magnetic wedge, the low magnetic permeability portion is preferably non-ferromagnetic.

[0013] A rotating electric machine according to the present invention uses any one of the magnetic wedges described above. Effect of the Invention

[0014] According to the present invention, it is possible to provide a magnetic wedge that can achieve both high levels of efficiency and torque in a rotating electrical machine. [Brief description of the drawings]

[0015] [Figure 1] 1 is a perspective view of a magnetic wedge according to a first embodiment of the present invention; [Diagram 2] 1 is an enlarged schematic diagram of a cross section of a magnetic wedge according to a first embodiment of the present invention. [Diagram 3] FIG. 4 is a perspective view of a magnetic wedge according to a second embodiment of the present invention. [Figure 4] FIG. 11 is a schematic diagram of a rotating electric machine according to a third embodiment of the present invention. [Diagram 5] 1 is a SEM photograph showing a cross-sectional structure of an example of a magnetic wedge. [Figure 6] 1 is a graph showing a DC magnetization curve of a high magnetic permeability portion. [Figure 7] 1 is a graph showing iron loss in a high permeability portion. [Figure 8] FIG. 2 is a model diagram of a rotating electric machine used in an electromagnetic field analysis. [Figure 9] FIG. 2 is a schematic diagram showing a cross-sectional structure of an embodiment; [Figure 10] FIG. 13 is a schematic diagram showing a cross-sectional structure of a comparative example. [Figure 11] 4 is a graph showing an electromagnetic field analysis result of a rotating electric machine. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0017] (First embodiment) FIG. 1 shows a perspective view of a magnetic wedge 100. The magnetic wedge 100 is a magnetic wedge for a rotating electric machine, and has a high permeability portion and a low permeability portion with relatively different magnetic permeability from each other. The low permeability portion has a lower magnetic permeability than the high permeability portion. The high permeability portion is located in the center of the magnetic wedge in the width direction, and the low permeability portion is located on both ends of the magnetic wedge in the width direction. In this embodiment, the cross section perpendicular to the longitudinal direction is generally convex. Then, the first low permeability portion 21, the high permeability portion 10, and the second low permeability portion 22 are formed in this order from one end of the magnetic wedge 100 in the width direction (the magnetic path direction connecting adjacent teeth. The direction of rotation of the rotating electric machine (circumferential direction of the stator)) to the opposite end. The terms "high magnetic permeability portion" and "low magnetic permeability portion" indicate the relative relationship between the magnitude of magnetic permeability of both portions.

[0018] The high permeability portion 10 is located at approximately the center of the width of the magnetic wedge 100, within the range of the convex protruding portion, and is formed elongated along the longitudinal direction of the magnetic wedge 100. The high permeability portion 10 is also arranged so as to penetrate the magnetic wedge 100 in the thickness direction (direction perpendicular to the width direction (direction connecting adjacent teeth)). In the magnetic wedge 100 shown in FIG. 1, the cross section of the high permeability portion is rectangular, but this is not limited to this and various shapes such as a trapezoid can be applied. The approximate dimensions of the magnetic wedge 100 are, for example, 10 mm to 300 mm in the longitudinal direction, 2 mm to 20 mm in the width direction, and 1 to 5 mm in thickness.

[0019] The high magnetic permeability portion 10 can be a composite material made of soft magnetic particles, for example, either iron powder or Fe-based soft magnetic alloy powder, or both, and an electrically insulating material. The composite material has an electrically insulating material between the soft magnetic particles, which bonds the soft magnetic particles together and electrically isolates the particles, and by increasing the electrical resistance of the magnetic wedge 100, the eddy current loss generated in the magnetic wedge 100 can be suppressed.

[0020] With regard to the average particle size of the soft magnetic particles, by decreasing the particle size, it is possible to increase the electrical resistance and reduce eddy current loss, while by increasing the particle size, it is possible to increase the magnetic permeability of the high magnetic permeability portion and strengthen the magnetic wedge effect. From these viewpoints, the average particle size of the soft magnetic particles is preferably 200 μm or less, more preferably 100 μm or less, even more preferably 50 μm or less, preferably 2 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more.

[0021] As the electrically insulating material, either an organic or inorganic material can be used, such as epoxy resin, phenol resin, polyimide, polyphenylene sulfide, polyamide, polyamideimide, silicon resin, colloidal silica, low melting point glass, etc. When using these, the ferromagnetic powder and the electrically insulating material can be mixed, and then the product can be produced by a method such as transfer molding, injection molding, hot pressing, etc.

[0022] In addition, as one form of the high permeability portion 10, the ferromagnetic particles may be an Fe-based alloy containing element M, which is more easily oxidized than Fe, and an oxide phase of element M may be generated between soft magnetic particles to bond the particles together. In order to manufacture the high permeability portion 10 in this form, the soft magnetic particles are press-molded and then heat-treated in an atmosphere containing oxygen, so that the oxide phase of element M can grow on the grain boundaries. In this form, the proportion of electrically insulating material on the grain boundaries can be minimized, and the density is increased, resulting in high strength and high permeability, which is more preferable. As the element M, one or more of Al, Si, Cr, Zr, Hf, etc. may be used. Here, "element M, which is more easily oxidized than Fe" means an element whose standard Gibbs energy of oxide formation is lower than that of Fe2O3.

[0023] The low permeability parts 21, 22 can be formed using the above-mentioned electrically insulating material. The low permeability part and the high permeability part can be produced separately and integrated by adhesion, welding, or the like to form the form shown in FIG. 1. It is also possible to integrally mold the low permeability material and the high permeability material by a two-color molding method or the like. The electrically insulating material contained in the high permeability part 10 and the electrically insulating material forming the low permeability part may be the same or different materials. It is also possible to embed glass fiber or glass cloth inside the magnetic wedge 100 in order to improve its strength.

[0024] In addition, when Fe-based alloy particles containing element M, which is more easily oxidized than Fe, are used as the high permeability portion 10, and an oxide phase of element M is grown between the particles, the low permeability portions 21, 22 may be formed as follows. That is, the low permeability portions 21, 22 are composed of low permeability metal particles having a lower magnetic permeability than the above-mentioned Fe-based alloy. Here, the low permeability metal particles contain element M, which is more easily oxidized than Fe. The low permeability metal particles may be a single element of element M, an alloy mainly composed of M, or the same alloy system as the above-mentioned Fe-based alloy. In the case of the same alloy system, alloy particles with low magnetic permeability can be obtained by reducing the Fe composition amount compared to the Fe composition amount of the Fe-based alloy particles constituting the high permeability portion. Up to this point, the low permeability portions 21, 22 have been described as being composed of low permeability metal particles having a lower magnetic permeability than the above-mentioned Fe-based alloy, but they may be non-magnetic. These high and low permeability parts are set in a mold and pressed (sized) to produce an integrated molded body, which is then heat-treated in the presence of oxygen to generate an oxide phase of element M between the particles, thereby firmly bonding the particles and the boundaries between the low and high permeability parts.

[0025] 2 is an enlarged schematic diagram showing the boundary between the high magnetic permeability portion 10 and the low magnetic permeability portion 21 (22) in this configuration. The high magnetic permeability portion 10 is composed of a plurality of Fe-based soft magnetic alloy particles, and more specifically, is a compact of a plurality of Fe-based soft magnetic alloy particles 1 containing element M, which is more easily oxidized than Fe. Between the particles of the compact, there are voids 2, and a surface oxide phase 3 of the Fe-based soft magnetic alloy particles that bonds the Fe-based soft magnetic alloy particles 1 together. This surface oxide phase is an oxide phase containing element M. The low permeability portion 21 or 22 is composed of a plurality of low permeability metal particles 4 having a lower magnetic permeability than the Fe-based soft magnetic alloy particles 1. The low permeability metal particles 4 are characterized in that they contain element M, which is more easily oxidized than Fe. The low permeability metal particles 4 have gaps 2 between them and a surface oxide phase 5 that bonds the low permeability metal particles 4 together. The surface oxide phase is an oxide phase containing element M. Furthermore, a surface oxide phase 6 is formed where the Fe-based soft magnetic alloy particle 1 and the low magnetic permeability metal particle 4 are adjacent to each other. The surface oxide phase 6 is formed by bonding and integrating the surface oxide phase 3 of the Fe-based soft magnetic alloy particle 1 and the surface oxide phase 5 of the low magnetic permeability metal particle 4, and the components of the adjacent particles are different. However, by containing the same element M in the Fe-based soft magnetic alloy particle 1 and the low magnetic permeability metal particle 4, the surface oxide phase 6 can be made to be a more homogeneous surface oxide phase 6 mainly composed of element M. This allows the Fe-based soft magnetic alloy particle 1 and the low magnetic permeability metal particle 4 to be firmly bonded to each other.

[0026] Second embodiment Next, a magnetic wedge 200 according to a second embodiment of the present invention will be described. The magnetic wedge 200 according to this embodiment differs from the magnetic wedge 100 according to the first embodiment only in shape. Furthermore, since the same configurations as those in the first embodiment have the same effects, the same symbols are used and the description is omitted.

[0027] The magnetic wedge is attached by fitting into a protrusion or groove formed on the teeth of the stator as described below. Therefore, depending on the fitting form, the cross section of the magnetic wedge can have various shapes. In the first embodiment, the magnetic wedge is described as having a shape with steps at both ends, but for example, as shown in FIG. 3, both ends of the magnetic wedge 200 may be tapered. Such a shape is preferable because it can reduce stress concentration at the corners of the groove formed in the stator. In addition, in the magnetic wedge 200 shown in FIG. 3, the cross section of the high magnetic permeability part is rectangular, but this is not limited to this, and various shapes such as a trapezoid can be applied.

[0028] Third embodiment Next, a rotating electric machine 300 according to a third embodiment of the present invention will be described. 4 is a schematic diagram of a rotating electric machine 300, showing a cross-sectional structure perpendicular to the rotation axis of the rotating electric machine 300. The rotating electric machine 300 is a radial gap type rotating electric machine, in which a stator 35 and a rotor 32 are arranged coaxially. The stator 35 has a plurality of teeth 34 around which coils 33 are wound, which are arranged at equal intervals in the circumferential direction.

[0029] In the rotating electric machine 300 of this embodiment, the magnetic wedge 100 of the first embodiment or the magnetic wedge 200 of the second embodiment is disposed at the rotor 32 side tip of the tooth so as to connect the tip of the adjacent tooth .

[0030] Here, the relative permeability and saturation magnetic flux density of the teeth 34 are usually designed to be higher than those of the magnetic wedge 100 or 200. As a result, the magnetic flux from the rotor 32 that reaches the magnetic wedge 100 or 200 flows into the teeth 34 via the magnetic wedge 100 or 200, and the magnetic flux that reaches the coil is suppressed, thereby reducing eddy current loss generated in the coil. Furthermore, when the rotating electric machine is driven, most of the magnetic flux in the teeth 34 generated by the coil current flows into the rotor 32 across the gap, but a part of it is attracted to the magnetic wedge and spreads in the circumferential direction. As a result, the magnetic flux distribution in the gap between the stator 35 and the rotor 32 becomes gentle, and for example, in a rotating electric machine in which a permanent magnet is arranged in the rotor 32, cogging can be suppressed and eddy current loss generated in the rotor 32 can be reduced. Furthermore, for example, in an induction type rotating electric machine in which a cage conductor is arranged in the rotor 32, secondary copper loss can be reduced. As described above, by disposing the magnetic wedge 100 or 200 according to the present invention in a rotating electric machine, it is possible to reduce losses and achieve a highly efficient and high-performance rotating electric machine 300. EXAMPLES

[0031] (Magnetic properties of high permeability part) An example of the first embodiment in which Fe-Al-Cr alloy particles containing Al and Cr, which are elements more easily oxidized than Fe, are used in the high permeability portion will be described below.

[0032] (Preparation of samples for measuring magnetic properties) An alloy powder (Fe-based soft magnetic powder) of Fe-5%Al-4%Cr (mass%) was produced by high-pressure water atomization. The average particle size (median diameter) of the produced powder was 12 μm. Polyvinyl alcohol (PVA) and ion-exchanged water were added to this alloy powder to produce a slurry, which was then spray-dried using a spray dryer to obtain a granulated powder. The amount of PVA added was 0.75 parts by mass when the raw powder was 100 parts by mass. Zinc stearate was added to the obtained granulated powder at a ratio of 0.4 parts by mass and mixed. The obtained mixed powder was filled into a mold and press-molded at room temperature with a molding pressure of 0.9 GPa. The produced molded body was heat-treated in air at 750 °C for 1 hour to obtain a sample for evaluating magnetic properties. The magnetic measurement samples were prepared in the form of a flat plate measuring 10 mm x 10 mm x 1.5 mm thick for DC magnetization curve measurement, and in the form of a ring measuring 13.4 mm outer diameter x 7.7 mm inner diameter x 2.0 mm thick for iron loss measurement.

[0033] (Cross-sectional structure of high permeability part) A scanning electron microscope (SEM / EDX) was used to observe the cross section of the high permeability part produced as described above, and the distribution of each constituent element was also investigated. The results are shown in Figure 4. Figure 5(a) is an SEM image, and Figures 5(b) to (e) are mapping images showing the distribution of Fe (iron), Al (aluminum), Cr (chromium), and O (oxygen), respectively. Brighter colors indicate more of the target element. Figure 5 shows that there is a lot of aluminum and oxygen at the grain boundaries between the Fe-based soft magnetic particles, and that an oxide phase has been formed. It can also be seen that the soft magnetic particles are bonded to each other via this oxide phase.

[0034] (DC magnetization curve) The DC magnetization curve (BH curve) of the sample was measured using a DC magnetic flux meter (TRF-5AH manufactured by Toei Kogyo) by clamping the above 10 mm square sample between the magnetic poles of an electromagnet and applying a maximum magnetic field of 500 kA / m. The measurement results at room temperature are shown in Figure 6. At an applied magnetic field of 160 kA / m, the magnetic flux density was 1.60 T and the relative permeability μ was 8.0. In the motor characteristic simulation described below, these measured values ​​were used as the BH curve for the high permeability portion.

[0035] (iron loss) The primary and secondary windings were made of polyurethane-coated copper wire on the ring sample. The number of turns was 50 turns on both the primary and secondary sides. The sample was connected to a BH analyzer (IFG BH-550) equipped with a large current bipolar power supply to measure the iron loss Pcv. The measurement conditions were frequency f = 50Hz to 1kHz, and maximum magnetic flux density Bm = 0.05 to 1.55T. In order to prevent the sample temperature from increasing due to Joule heat from the primary winding, the sample was immersed in a cooling tank with a coolant temperature maintained at 23°C to measure the iron loss. Silicone oil was used as the coolant. The measurement results are shown in Figure 7. The white circles in the figure are the measured values. As shown in the figure, in the high Bm region, the magnetic saturation is approached, and the Pcv tends to gradually saturate. In the motor characteristic evaluation in the next section, this measured value was used as the iron loss of the high permeability part. Although actual measurements were only possible up to Bm=1.55T, it is possible that inside the motor the magnetic wedge can be magnetized up to about 2T, which is equivalent to the saturation magnetic flux density of the electromagnetic steel sheet. Therefore, for Pcv values ​​on the high Bm side exceeding 1.55T, the measurement results were applied to the following formula using the least squares method, and the extrapolated value from this formula was used. Pcv=6.9f / (1+(1.28 / Bm) 2 ) Here, the unit of Pcv is kW / m 3 , Bm is in T, and f is in Hz. The solid line in Figure 6 is the calculated value of this formula.

[0036] (Evaluation of rotating electrical machine characteristics) The characteristics (efficiency and torque) of an induction type rotating electric machine in which the magnetic wedge of the embodiment or the comparative example is installed were calculated using a two-dimensional electromagnetic field simulation using the finite element method. At that time, the above-mentioned BH curve and iron loss value were incorporated into the calculation as the magnetic characteristics of the high permeability part of each magnetic wedge. The specifications of the induction type rotating electric machine used in the electromagnetic field simulation are as follows: Stator: diameter 450mm x height 162mm Number of poles: 4 Number of slots: 36 Rotor and stator material: Electromagnetic steel sheet (50A1000) Rotating motor output: 150kW Rotational speed: 1425 rpm

[0037] Figure 8 shows the installation position of the magnetic wedge 100 used in this evaluation. The cross-section of the magnetic wedge 100 is T-shaped. The width of the magnetic wedge 100 (the length in the circumferential direction of the rotating electrical machine) is 12.0 mm on the coil 33 side and 7.0 mm on the rotor 32 side. The thickness at the center in the width direction of the magnetic wedge 100 (the length in the radial direction of the rotating electrical machine) is 3.0 mm, and the thickness of the stepped portion is 1.5 mm.

[0038] (Example) A schematic cross-sectional view of the magnetic wedge 100 of the example is shown in FIG. 9. The example consists of a high magnetic permeability portion 10 located at the center in the width direction and low magnetic permeability portions 21 and 22 located on both sides thereof. The magnetic characteristics of the high magnetic permeability portion 10 are as described above, and the width x of the high magnetic permeability portion is in the range of 0 < x < 12 mm. Also, the low magnetic permeability portions 21 and 22 are made non-magnetic and the relative permeability is fixed at 1.

[0039] (Comparative Example) A schematic cross-sectional view of the magnetic wedge 100 of the comparative example is shown in FIG. 10. The comparative example consists of a high magnetic permeability portion 10 located on the rotor side and a low magnetic permeability portion 21 located on the coil side. The magnetic characteristics of the high magnetic permeability portion 10 are as described above, and the thickness y of the high magnetic permeability portion is in the range of 0 ≤ y ≤ 3 mm. Also, the low magnetic permeability portion 21 is made non-magnetic and the relative permeability is fixed at 1. In this comparative example, when y = 0, the entire magnetic wedge 100 becomes a non-magnetic body, and when y = 3 mm, the entire magnetic wedge 100 becomes a high magnetic permeability portion.

[0040] (Rotating Electrical Machine Characteristic Evaluation Results) Table 1 shows the efficiency and torque of the rotating electrical machine using the magnetic wedge of the example, and Table 2 shows the efficiency and torque of the rotating electrical machine when using the magnetic wedge of the comparative example. Also, FIG. 11 shows the results of Table 1 and Table 2 with the efficiency of the rotating electrical machine on the horizontal axis and the torque on the vertical axis. In FIG. 11, the higher the position on the graph towards the upper right, the higher the efficiency and torque, indicating good characteristics. First, looking at the results of the magnetic wedges of the comparative examples, Comparative Example 1, which is entirely non-magnetic, has the highest torque but the lowest efficiency. As the number of high permeability parts is increased (Comparative Examples 2 to 4), the efficiency improves but the torque decreases. Comparative Example 5, which is entirely high permeability, has the highest efficiency among the comparative examples but the lowest torque. The above-mentioned trade-off relationship in the comparative examples is shown by the dotted line in Figure 11. On the other hand, all plot points of the calculation results of the working example are located to the upper right of the dotted line, and show excellent characteristics that combine high torque and high efficiency compared to the comparative example. Conventionally used magnetic wedges are magnetic wedges made entirely of high permeability parts, as in comparative example 5. Compared to comparative example 5, the working example is superior in both torque and efficiency, making it possible to provide a rotating electric machine with excellent characteristics that could not be achieved with conventional magnetic wedges.

[0041] [Table 1]

[0042] [Table 2]

[0043] Although the present invention has been described above using the above embodiment, the technical scope of the present invention is not limited to the above embodiment. The contents can be modified within the technical scope described in the claims. [Explanation of symbols]

[0044] 1:Fe-based soft magnetic particles 2:Void 3: Surface oxide phase 4: Low permeability metal particles 5: Surface oxide phase 6: Surface oxide phase 10: High permeability part 21, 22: Low permeability part 31: Gap 32:Rota 33: Coil 34: Teeth 35:Stator 100, 200: Magnetic wedge 300: Rotating motor

Claims

1. A magnetic wedge for a rotating electric machine, comprising: The magnetic flux has a high magnetic permeability portion and a low magnetic permeability portion, the permeability of which is relatively different from each other, the permeability of the low permeability portion is lower than the permeability of the high permeability portion, the high permeability portion is located at a center portion in a width direction of the magnetic wedge, The low magnetic permeability portions are located on both ends of the magnetic wedge in a width direction, the high magnetic permeability portion includes soft magnetic particles and an electrically insulating material between the soft magnetic particles, the soft magnetic particles being a plurality of Fe-based soft magnetic alloy particles containing an element M which is more easily oxidized than Fe, the high magnetic permeability portion includes the Fe-based soft magnetic alloy particles bound together by an oxide phase containing the element M, The low magnetic permeability portion contains an element M which is more easily oxidized than Fe, and is configured by binding a plurality of metal particles having a lower magnetic permeability than the Fe-based soft magnetic alloy particles with an oxide phase containing the element M. A magnetic wedge characterized by:

2. 2. The magnetic wedge according to claim 1, wherein said element M is at least one of Al, Si, Cr, Zr, and Hf.

3. 3. A magnetic wedge according to claim 1 or 2, characterized in that the low permeability portion is non-ferromagnetic.

4. A rotating electric machine comprising the magnetic wedge according to any one of claims 1 to 3.

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