Magnetic gears and magnetically geared electric machines

Abstract

To provide a magnetic gear with suppressed loss of an eddy current of a magnetic pole piece unit, and a magnetic geared electric machine.SOLUTION: A magnetic pole piece unit of a magnetic gear includes a magnet pole piece support having connection parts connected to ends of a plurality of magnetic pole pieces and a radial extension part extending toward a radially inner side from the connection parts. A first yoke unit includes an end plate arranged at an axial end face of a first body part and lying opposite the radial extension part at a prescribed interval in an axial direction. The end plate has a magnetic material part formed of a magnetic material, and a non-magnetic material part formed of a non-magnetic material and arranged on a radially outer side of the magnetic material part.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to magnetic gears and magnetically geared electric machines. [Background technology]

[0002] Conventionally, magnetic gears configured to transmit magnetic torque have been known. For example, Patent Document 1 discloses a magnetic-geared electric machine incorporating a magnetic gear. This magnetic-geared electric machine includes, in order from the radially inner side, an internal rotor supporting multiple permanent magnets, a pole piece unit including multiple pole pieces, and a stator. The stator is provided with multiple windings and multiple stator magnets. The pole piece unit illustrated in this document functions as an external rotor that rotates on the outer periphery of the internal rotor. When the internal rotor rotates due to a rotating magnetic field generated in response to three-phase alternating current flowing through the windings, the pole pieces modulate the magnetic flux between the internal rotor and the stator. The modulated magnetic field and the magnetic field of the stator magnet cause the pole piece unit to rotate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5643857 Summary of the Invention [Problem to be solved by the invention]

[0004] When a magnetic gear operates, axially flowing magnetic flux passes through the pole pieces as leakage flux, causing eddy currents to flow in the pole pieces, resulting in eddy current loss. The leakage flux can also flow through other components that make up the pole piece unit. For example, in a configuration in which a pole piece unit is provided with a facing component that faces the internal rotor in the axial direction, eddy current loss can also occur in the facing component when leakage flux passes through the facing component. In particular, in a configuration in which the facing component is connected to the rotating shaft of the magnetic gear via a bearing, there is a concern that the temperature of the bearing may exceed the allowable temperature if the facing component heats up due to the generation of eddy currents. Therefore, it is necessary to suppress eddy current loss in the pole piece unit.

[0005] An object of the present disclosure is to provide a magnetic gear and a magnetic-geared electric machine that suppress eddy current losses in the pole piece units. [Means for solving the problem]

[0006] A magnetic gear according to at least one embodiment of the present disclosure includes: a first yoke unit including a first main body portion having a plurality of first magnets arranged in a circumferential direction about an axis and a first yoke supporting the plurality of first magnets; a second yoke unit including a plurality of second magnets arranged in the circumferential direction on the outer circumferential side of the first yoke unit; a pole piece unit including a plurality of pole pieces arranged in the circumferential direction between the first yoke unit and the second yoke unit; A magnetic gear comprising: the pole piece unit further includes a pole piece support having a connecting portion connected to an end of each of the plurality of pole pieces and a radial extending portion extending radially inward from the connecting portion; the first yoke unit further includes an end plate disposed on an end surface of the first main body portion in the axial direction, the end plate facing the radially extending portion with a predetermined gap in the axial direction, The end plate is a magnetic portion formed of a magnetic material; a non-magnetic material portion formed of a non-magnetic material and disposed radially outward of the magnetic material portion; It has.

[0007] A magnetic-geared electric machine according to at least one embodiment of the present disclosure comprises: The magnetic gear; a coil provided on a second yoke supporting the second magnet; a rotating shaft for transmitting torque between an external rotating device and the magnetic gear; Equipped with. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to provide a magnetic gear and a magnetic-geared electric machine in which eddy current loss in the pole piece unit is suppressed. [Brief explanation of the drawings]

[0009] [Figure 1A] FIG. 1 is a schematic diagram of a magnetic gear according to an embodiment. [Figure 1B] FIG. 10 is a schematic view of a magnetic gear according to another embodiment. [Figure 2A] FIG. 2 is a schematic diagram showing an example of a schematic internal structure of a magnetic gear. [Figure 2B] FIG. 10 is a schematic diagram showing another example of the schematic internal structure of a magnetic gear. [Figure 3] FIG. 2 is a schematic diagram showing details of the internal structure of a magnetic gear according to an embodiment. [Figure 4] 10 is a schematic graph showing eddy current loss obtained by simulation. [Figure 5] FIG. 2 is a schematic diagram of an end plate according to one embodiment. [Figure 6] 1 is a schematic graph showing the relationship between the dimension L and the distance R and the loss rate. [Figure 7] 1 is a schematic graph showing the relationship between the dimension D and the distance S and the loss rate. [Figure 8] FIG. 3 is a schematic view showing one end portion in the axial direction of a first yoke unit according to one embodiment. [Figure 9]1 is a schematic view showing a steel plate according to an embodiment as viewed in an axial direction; [Figure 10A] 1 is a schematic diagram of a magnetic-geared electric machine (magnetic-geared generator) according to one embodiment. [Figure 10B] 1 is a schematic diagram of a magnetic-geared electric machine (magnetic-geared generator) according to another embodiment. [Figure 10C] 1 is a schematic diagram of a magnetic-geared electric machine (magnetic-geared motor) according to one embodiment. [Figure 10D] FIG. 1 is a schematic diagram of a magnetic-geared electric machine (magnetic-geared motor) according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, several embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of components described as embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the present disclosure.

[0011] <1. Overview of Magnetic Gear 5> 1A and 1B are schematic diagrams of a magnetic gear 5 according to some embodiments of the present disclosure. In the following description, the "axial direction" is a direction parallel to the axis Q of the magnetic gear 5, the "radial direction" is a direction perpendicular to the axis Q of the magnetic gear 5, and the "circumferential direction" is a circumferential direction based on the axis Q of the magnetic gear 5. The magnetic gear 5 has a rotation axis A for transmitting power to an external rotating device (described later), and the axis of this rotation axis A coincides with the axis Q.

[0012] 1A and 1B includes a first yoke unit 10, a pole piece unit 30, and a second yoke unit 20. All three units extend in the axial direction.

[0013] The first body portion 11, a component of the first yoke unit 10, has a plurality of first magnets 19 arranged in the circumferential direction with respect to the axis Q and a first yoke 15 supporting the plurality of first magnets 19. The second body portion 21, a component of the second yoke unit 20, has a plurality of second magnets 29 arranged in the circumferential direction and a second yoke 25 supporting the plurality of second magnets 29. The pole piece unit 30 includes a plurality of pole pieces 50 and a pair of pole piece supports 37. The plurality of pole pieces 50 are arranged in the circumferential direction between the first yoke unit 10 and the second yoke unit 20. The pair of pole piece supports 37 are respectively connected to both ends of each of the plurality of pole pieces 50 in the axial direction. As an example, each of the plurality of pole pieces 50 has a plurality of electromagnetic steel plates 150 stacked in the axial direction (see FIG. 3). The pole piece unit 30 of this example further includes a plurality of holders (not shown) that sandwich the plurality of pole pieces 50 in the circumferential direction. The axial ends of each of the holders are also connected to a pair of pole piece supports 37. The holders may form a ring-shaped member. In some embodiments, the number of second magnets 29 is greater than the number of pole pieces 50, and the number of pole pieces 50 is greater than the number of first magnets 19. The circumferential length of the first magnets 19 is greater than the circumferential length of the second magnets 29.

[0014] In the magnetic gear 5 of the present disclosure, one of the first yoke unit 10, the second yoke unit 20, and the pole piece unit 30 functions as a stator, and the remaining two function as rotors. Below, we will explain magnetic gear 5A(5) in which the second yoke unit 20 functions as a stator, and magnetic gear 5B(5) in which the pole piece unit 30 functions as a stator.

[0015] <1-1. Magnetic gear 5A(5) according to one embodiment> The magnetic gear 5A (5) illustrated in FIG. 1A includes a housing 98 that may be mounted on a base 101. In the example illustrated in the figure, the second yoke unit 20 functions as a stator, and the rotation axis A includes a first rotation axis A1 and a second rotation axis A2 that are coaxial with each other. The housing 98 rotatably supports the first rotation axis A1, which may function as an input shaft. One of a pair of pole piece supports 37 is connected via the first rotation axis A1, and the other is connected to the second rotation axis A2 via a bearing B1. Therefore, the pole piece unit 30 illustrated in the figure functions as a rotor that rotates together with the first rotation axis A1. The second rotation axis A2, which may function as an output shaft, supports the first yoke unit 10 disposed between the pair of pole piece supports 37. Therefore, the first yoke unit 10 illustrated in the figure functions as a rotor that rotates together with the second rotation axis A2. The second rotation axis A2 is rotatably supported by the housing 98 via a bearing. One end of the second rotating shaft A2 may be connected to the first rotating shaft A1 via a bearing, or may be unconnected to the first rotating shaft A1.

[0016] The magnetic gear 5A operates, for example, as follows: When the first rotating shaft A1, which serves as the input shaft, rotates together with the pole piece unit 30, the relative positional relationship between the multiple pole pieces 50 and the multiple first magnets 19 and multiple second magnets 29 changes. This modulates the magnetic flux between the first yoke unit 10 and the second yoke unit 20, and the first magnet 19 receives a magnetic force from the modulated magnetic field, causing the first yoke unit 10 to rotate. As a result, the second rotating shaft A2, which serves as the output shaft, rotates.

[0017] In the magnetic gear 5A, the second rotating shaft A2 may function as the input shaft, and the first rotating shaft A1 may function as the output shaft. Even in this case, when the first yoke unit 10 rotates together with the second rotating shaft A2, the relative positional relationship between the multiple pole pieces 50 and the multiple first magnets 19 changes. This modulates the magnetic flux between the first yoke unit 10 and the second yoke unit 20, and the pole pieces 50 receive a magnetic force from the modulated magnetic field, causing the pole piece unit 30 to rotate. As a result, the first rotating shaft A1 rotates as the output shaft.

[0018] In the magnetic gear 5A described above, if the number of magnetic poles in the pole piece 50 of the pole piece unit 30 is NL, the number of magnetic pole pairs (number of pole pairs) in the first magnet 19 of the first yoke unit 10 is NH, and the number of magnetic pole pairs (number of pole pairs) in the second magnet 29 of the second yoke unit 20 is NS, then NL = NH + NS holds. When this relational expression holds, the ratio of the rotation speed of the first yoke unit 10 to the pole piece unit 30 is expressed as NL / NH. In this example, NL / NH is greater than 1, so the first yoke unit 10 functions as a high-speed rotor, and the pole piece unit 30 functions as a low-speed rotor. Note that the number of magnetic poles NL in the pole piece 50 is less than the number of pole pairs NS in the second magnet 29.

[0019] <1-2. Magnetic gear 5B(5) according to another embodiment> In a magnetic gear 5B(5) according to another embodiment illustrated in FIG. 1B, the pole piece unit 30 functions as a stator, and the first yoke unit 10 and the second yoke unit 20 function as a rotor. The rotation axis A includes a first rotation axis A1 and a second rotation axis A2 that are coaxial with each other. The magnetic gear 5B includes a housing 96 that may be mounted on a base 101, and the pole piece unit 30 is supported by the housing 96. A pair of pole piece supports 37 may be integrally formed with the housing 96. One of the pair of pole piece supports 37 in this example rotatably supports the second rotation axis A2, which may function as an output shaft, via a bearing B1.

[0020] The first rotating shaft A1, which may function as an input shaft, is rotatably supported by a support unit (not shown) and is connected to the second yoke unit 20 via a connecting member 95. The second yoke unit 20 may be connected to the pole piece unit 30 via a bearing. The second rotating shaft A2 may be connected to the first rotating shaft A1 via a bearing, or may be unconnected to the first rotating shaft A1.

[0021] The magnetic gear 5B operates, for example, as follows: When the first rotating shaft A1, which serves as the input shaft, rotates together with the second yoke unit 20, the relative positional relationship between the multiple pole pieces 50 and the multiple second magnets 29 changes. This modulates the magnetic flux between the first yoke unit 10 and the second yoke unit 20, and the first magnet 19 receives a magnetic force from the modulated magnetic field, causing the first yoke unit 10 to rotate. As a result, the second rotating shaft A2, which serves as the output shaft, rotates.

[0022] In the magnetic gear 5B described above, the second rotating shaft A2 may function as the input shaft, and the first rotating shaft A1 may function as the output shaft. Even in this case, when the first yoke unit 10 rotates together with the second rotating shaft A2, the relative positional relationship between the multiple pole pieces 50 and the multiple first magnets 19 changes. This modulates the magnetic flux between the first yoke unit 10 and the second yoke unit 20, and the second magnet 29 receives a magnetic force from the modulated magnetic field, causing the second yoke unit 20 to rotate. As a result, the first rotating shaft A1 rotates as the output shaft.

[0023] <1-3. Supplement to Magnetic Gear 5> The magnetic gear 5 illustrated in FIGS. 1A and 1B may be incorporated into a magnetic-geared electric machine 1 (more specifically, a magnetic-geared generator 2 or a magnetic-geared motor 3) (see FIGS. 10A to 10D). When the magnetic gear 5 is incorporated into a magnetic-geared generator 2, the rotating shaft A may not include either the first rotating shaft A1 or the second rotating shaft A2, which function as an output shaft. When the magnetic gear 5 is incorporated into a magnetic-geared motor 3, the rotating shaft A may not include either the first rotating shaft A1 or the second rotating shaft A2, which function as an input shaft. Furthermore, regardless of whether the magnetic gear 5 is incorporated into a magnetic-geared generator 2 or a magnetic-geared motor 3, the rotating shaft A may be formed of a single shaft member. Although not shown in detail, in this embodiment, a single rotating shaft A may be rotatably supported by a housing 98 (see FIG. 1A) and rotatably coupled to a first yoke unit 10, and a pair of pole piece supports 37 may be fixed to the outer periphery of the rotating shaft A. In this case, the first yoke unit 10 and the pole piece unit 30 function as a rotor, and the second yoke unit 20 functions as a stator.

[0024] <2. Overview of the internal structure of Magnetic Gear 5> 2A and 2B are schematic diagrams showing the internal structure of a magnetic gear 5 according to some embodiments of the present disclosure. In the schematic diagrams of FIGS. 2A and 2B, the circumferential direction is linearly illustrated. In the internal structure of the magnetic gear 5, each axially extending pole piece 50 faces the first yoke unit 10 across a first gap G1 and faces the second yoke unit 20 across a second gap G2. In some embodiments of the present disclosure, at least one of the outer peripheral surface or the inner peripheral surface of the pole piece 50 may be covered with a pole piece cover (not shown). The material forming the pole piece cover is preferably a non-magnetic material, and more preferably a non-magnetic and non-conductive material. In an embodiment in which the pole piece covers include an outer pole piece cover covering the outer peripheral surface of the pole piece 50 and an inner pole piece cover covering the inner peripheral surface of the pole piece 50, each pole piece 50 faces the first yoke unit 10 across the first gap G1 and the inner pole piece cover, and faces the second yoke unit 20 across the second gap G2 and the outer pole piece cover. Note that the pole piece covers may not only cover the pole pieces 50, but may also cover at least one of the outer peripheral surface or the inner peripheral surface of the holder described above.

[0025] <2-1. An example of the schematic internal structure of the magnetic gear 5> 2A has a first body portion 11A (11) of a first yoke unit 10A (10) that has a plurality of first magnets 19 and a first yoke 15A (15) that supports the plurality of first magnets 19. The first body portion 11A (11) has a surface permanent magnet (SPM) structure in which the plurality of first magnets 19 are provided on the surface of the first yoke 15. Therefore, the plurality of first magnets 19 face the plurality of pole pieces 50 with a first gap G1 between them (or with the first gap G1 and the inner pole piece cover between them).

[0026] The second body portion 21 of the second yoke unit 20 shown in the figure has a plurality of second magnets 29 and a second yoke 25 that supports the plurality of second magnets 29. The second yoke 25 has a stator core 27 extending in the circumferential direction and a plurality of teeth 28 that protrude radially inward from the stator core 27. The plurality of teeth 28 are arranged at intervals in the circumferential direction, and the plurality of second magnets 29 are arranged on the tip side of the plurality of teeth 28. Although detailed illustration is omitted, the second yoke 25 does not have to have a plurality of teeth 28. In this case, the plurality of second magnets 29 may be attached to the inner circumferential surface of the stator core 27.

[0027] <2-2. Another example of the schematic internal structure of the magnetic gear 5> The first body portion 11B(11) of the first yoke unit 10B(10) shown in FIG. 2B has a plurality of first magnets 19 and a first yoke 15B(15) that supports the plurality of first magnets 19. The first body portion 11B(11) has an interior permanent magnet (IPM) structure in which the plurality of first magnets 19 are arranged inside the first yoke 15. Therefore, the first yoke 15 faces the plurality of pole pieces 50 with a first gap G1 between them (or with the first gap G1 and the above-mentioned inner pole piece cover between them). The second yoke unit 20 shown in FIG. 2B is the same as the second yoke unit 20 shown in FIG. 2A. The second yoke unit 20 shown in FIG. 2B does not necessarily have a plurality of teeth 28.

[0028] <3. Details of the internal structure of Magnetic Gear 5> 3 to 9, details of the internal structure of the magnetic gear 5 according to some embodiments of the present disclosure are illustrated. Fig. 3 is a schematic diagram showing details of the internal structure of the magnetic gear 5 according to one embodiment, illustrating a first yoke 15 having an embedded magnet configuration. The following mainly describes the configuration of the magnetic gear 5 on one side in the axial direction.

[0029] As illustrated in FIG. 3, the pole piece support 37 of the pole piece unit 30 has connecting portions 35 connected to the ends of the multiple pole pieces 50, and radially extending portions 36 extending radially inward from the connecting portions 35. The connecting portions 35 and the radially extending portions 36 may be made of the same material or different materials. In the example shown in the figure, the radially inner end of the radially extending portion 36 is connected to the first rotation shaft A1. The inner end of the radially extending portion 36 may also be connected to the second rotation shaft A2 via a bearing B1 (see FIG. 1A).

[0030] The first yoke unit 10 includes an end plate 17. The end plate 17 is disposed on the end surface 11S of the first main body portion 11 in the axial direction. More specifically, at least a portion of the end plate 17 faces and contacts the end surface 11S of the first main body portion 11. The end plate 17 faces the radially extending portion 36 across a predetermined gap G3 in the axial direction. The end plate 17 includes a magnetic material portion 18 formed of a magnetic material and a non-magnetic material portion 16 formed of a non-magnetic material. The magnetic material is, for example, a steel plate. Examples of non-magnetic metals include stainless steel and aluminum. The non-magnetic material is not limited to metal and may be, for example, a plastic such as carbon fiber reinforced plastic or glass fiber reinforced plastic. Carbon fiber reinforced plastic and glass fiber reinforced plastic are both non-magnetic and non-conductive materials. That is, the non-magnetic material forming the non-magnetic material portion 16 may be non-conductive. The non-magnetic material portion 16 is disposed radially outward of the magnetic material portion 18, and constitutes the radially outer end portion of the end plate 17. Note that the end plate 17 in Fig. 3 is not hatched to make the drawing easier to see (the same applies to Fig. 4).

[0031] The advantages of adopting the above configuration are as follows. When the magnetic gear 5 is in operation, leakage magnetic flux occurs between the first yoke unit 10 and the second yoke unit 20. The leakage magnetic flux is, for example, magnetic flux that flows axially through one end of each of the multiple pole pieces 50 (the leakage magnetic flux flows in the direction shown by arrow C1, but is not limited to this direction). In the magnetic gear 5 of the present disclosure, at least a portion of the leakage magnetic flux is induced to the magnetic material portion 18 of the end plate 17 (for example, arrow C2). This prevents the leakage magnetic flux from flowing into the pole piece support 37, reducing eddy current loss in the pole piece support 37. Furthermore, the non-magnetic material portion 16 is disposed radially outward of the magnetic material portion 18, and the non-magnetic material portion 16 is close to one axial end of the pole piece 50. Because magnetic flux tends to flow in a manner that avoids the non-magnetic material portion 16, it is possible to reduce the occurrence of leakage magnetic flux that passes through the pole piece 50 in the axial direction. As a result, a magnetic gear 5 is realized that suppresses eddy current loss in the pole piece unit 30 due to the generation of leakage magnetic flux. Furthermore, in an embodiment in which the inner end of the radially extending portion 36 is connected to the bearing B1 (see FIGS. 1A and 1B), the reduction in eddy current loss in the pole piece unit 30 can suppress a temperature rise in the radially extending portion 36, thereby preventing the temperature of the bearing B1 from exceeding an allowable temperature.

[0032] For the same reason, the above advantages can be obtained even in an embodiment in which the first yoke unit 10 has a surface magnet configuration. Also, even in an embodiment in which the radially extending portion 36 is not connected to the bearing B1, it is possible to suppress eddy current loss in the pole piece unit 30.

[0033] Simulations also confirm that the above advantages are achieved by arranging the magnetic material portion 18 and the non-magnetic material portion 16 radially outward of the magnetic material portion 18. FIG. 4 shows the eddy current losses in the magnetic gear 5 according to one embodiment, a first sample, and a second sample. The first sample is a magnetic gear in which the end plate 17 of the magnetic gear 5 is replaced with a first end plate made solely of the material of the non-magnetic material portion 16. The second sample is a magnetic gear in which the end plate 17 of the magnetic gear 5 is replaced with a second end plate including a magnetic material portion and a non-magnetic material portion aligned in the axial direction. In the second end plate, the magnetic material portion is located closer to the pole piece support 37 than the non-magnetic material portion. The first and second end plates are the same size as the end plate 17.

[0034] FIG. 4 shows the total eddy current loss, and the eddy current loss in the pole piece unit 30 as a percentage of the total eddy current loss is indicated by hatching. As shown in the figure, the magnetic gear 5 of this embodiment can reduce the eddy current loss in the pole piece unit 30 compared to the first sample, and can also reduce the overall eddy current loss. Furthermore, the magnetic gear 5 of this embodiment increases the eddy current loss in the pole piece unit 30 compared to the second sample, but can reduce the overall eddy current loss. Therefore, according to the simulation results, it can be seen that the magnetic gear 5 can reduce both the overall eddy current loss and the eddy current loss in the pole piece unit 30 in a balanced manner.

[0035] As mentioned above, the non-magnetic material forming the non-magnetic material portion 16 may be non-conductive. Even if the non-magnetic material portion 16 is non-magnetic, leakage magnetic flux still interlinks the non-magnetic material portion 16. In this regard, according to the above configuration, the eddy current loss of the non-magnetic material portion 16 can be suppressed by making the non-magnetic material forming the non-magnetic material portion 16 non-conductive. Therefore, the magnetic gear 5 can suppress the overall eddy current loss.

[0036] FIG. 5 is a schematic diagram of an end plate 17 according to an embodiment of the present disclosure. The end plate 17 shown in the figure has a configuration in which the magnetic material portion 18 and the non-magnetic material portion 16 are in direct contact with each other. A boundary 33 between the magnetic material portion 18 and the non-magnetic material portion 16 is, for example, parallel to the axial direction. The boundary 33 is located radially outward from the inner circumferential surface 19A of each of the multiple first magnets 19. With this configuration, the magnetic outer end 181, which is the radially outer end of the magnetic material portion 18, is close to the pole piece 50. This makes it easier for leakage magnetic flux generated in the pole piece 50 to be induced to the magnetic material portion 18, further suppressing eddy current loss in the pole piece unit 30.

[0037] In other embodiments, boundary 33 may be, for example, zigzag or stepped instead of being parallel to the axial direction. In this case, boundary 33 as a whole may be located radially outward from inner circumferential surface 19A. Another member may be interposed between magnetic material portion 18 and non-magnetic material portion 16. In this case, the another member corresponds to boundary 33. Furthermore, first yoke unit 10 may have a surface magnet configuration. The above advantages can be obtained in any of the embodiments.

[0038] In some embodiments of the present disclosure, where L is the radial dimension of the non-magnetic material portion 16 and R is the radial distance (shortest distance) between the pole piece 50 and the first yoke unit 10, the magnetic gear 5 satisfies the relationship R≦L≦6×R. It is more preferable that the magnetic gear 5 satisfies the relationship 2×R≦L≦4×R. Note that in the embodiment of FIG. 5 in which the first yoke 15 has an embedded magnet structure, the distance R is the shortest radial distance between the pole piece 50 and the first yoke 15. In the embodiment of FIG. 2A in which the first yoke 15 has a surface magnet structure, the distance R is the shortest radial distance between the pole piece 50 and the first magnet 19. According to the above configuration, satisfying the relationship L≦6×R (preferably the relationship L≦4×R) prevents the magnetic material portion 18 from being too far away from the pole piece 50, thereby suppressing short-circuiting of magnetic flux between the pole piece 50 and the magnetic material portion 18. Furthermore, satisfying the relationship L≧R (preferably the relationship L≧2×R) ensures a minimum size for the non-magnetic material portion 16, thereby suppressing the generation of leakage magnetic flux in the pole piece 50.

[0039] The effect of reducing eddy current loss by satisfying the relationship R≦L≦6×R can also be confirmed by simulation. FIG. 6 is a schematic graph showing the relationship between the dimension L and distance R and the loss ratio. The horizontal axis of the graph represents the ratio of the dimension L of the non-magnetic material portion 16 to the distance R (i.e., L / R). The vertical axis of the graph represents the total loss ratio in the magnetic gear 5 (more specifically, the magnetic-geared motor 3 described below). This total loss includes the total iron loss in the magnetic gear 5, such as the total eddy current loss in the magnetic gear 5. In this graph, the total loss in a configuration without the non-magnetic material portion 16 (i.e., a configuration where L=0) is 100%. In this simulation, L=0 refers to an embodiment in which the end plate 17 is composed only of the magnetic material portion 18. In the graph, the relationship between L / R and the loss ratio predicted based on four points calculated by the simulation is indicated by a thick solid line.

[0040] According to the same graph, in the range of 1 ≦ L / R ≦ 6, the overall loss is reduced by about 5% or more. Therefore, it is understood that if the magnetic gear 5 satisfies the relationship of R ≦ L ≦ 6×R, the overall loss will be reduced. According to this simulation, the reduction of the overall loss is brought about by the reduction of the eddy current loss in the pole piece support 37. It is understood that if the magnetic gear 5 satisfies the relationship of R ≦ L ≦ 6×R, the eddy current loss in the pole piece unit 30 will be reduced. Also, in the range of 2 ≦ L / R ≦ 4, the overall loss is reduced by about 8% or more. Therefore, it is understood that if the magnetic gear 5 satisfies the relationship of 2×R ≦ L ≦ 4×R, the eddy current loss in the pole piece unit 30 will be further reduced. In the same graph, as L / R exceeds 6, the reduction effect of the overall loss disappears because the non-magnetic material part 16 becomes too long in the radial direction, resulting in the pole piece 50 and the magnetic material part 18 being too far apart from each other, and the magnetic flux between the pole piece 50 and the magnetic material part 18 being short-circuited, increasing the eddy current loss in the pole piece unit 30.

[0041] Returning to FIG. 5, in some embodiments of the present disclosure, when the dimension of the magnetic material part 18 in the axial direction is D and the distance (shortest distance) in the axial direction between the radially extending part 36 and the first main body part 11 is S, the magnetic gear 5 satisfies the relationship of D ≧ 0.15×S. As a more specific example, the magnetic gear 5 satisfies the relationship of 0.15×S ≦ D < S. By satisfying the relationship of D < S, the contact between the end plate 17 and the pole piece support 37 is avoided. According to the above configuration, by satisfying the relationship of D ≧ 0.15×S, it is avoided that the magnetic material part 18 becomes too short in the axial direction, and the short-circuit of the magnetic flux between the pole piece 50 and the magnetic material part 18 can be suppressed.

[0042] The effect of reducing eddy current loss due to the relationship D≧0.15×S can also be confirmed by simulation. FIG. 7 is a schematic graph showing the relationship between the dimension D, the distance S, and the loss ratio. The horizontal axis of this graph represents the ratio of the dimension D of the magnetic material portion 18 to the distance S (i.e., D / S). The vertical axis of this graph, similar to the vertical axis of FIG. 6, represents the percentage of total loss in the magnetic gear 5 (more specifically, the magnetic-geared motor 3 described below). The total loss in a configuration without the magnetic material portion 18 (i.e., a configuration where D=0) is 100%. Note that in this simulation, D=0 refers to an embodiment without an end plate 17. For convenience, the graph shows a thick solid line connecting four points calculated by the simulation. According to this graph, when D / S is 0.15 or more, the total loss is reduced by 10% or more. According to the present simulation, a reduction of more than 10% in overall loss is brought about by a reduction in eddy current loss in the pole piece support 37, and it is understood that if the magnetic gear 5 satisfies the relationship D≧0.15×S, the eddy current loss in the pole piece unit 30 will be further reduced.

[0043] Returning to FIG. 4 , in some embodiments of the present disclosure, the radial extension portion 36 of the pole piece unit 30 is formed of a non-magnetic material. Specific materials for the non-magnetic material have been described above. According to the above configuration, since the radial extension portion 36 is a non-magnetic material, leakage magnetic flux from the pole piece 50 to the radial extension portion 36 can be further suppressed, thereby suppressing eddy current loss in the pole piece unit 30. The radial extension portion 36 of this example is formed of a non-magnetic and non-conductive material. Specific materials for the non-magnetic and non-conductive material have been described above. According to the above configuration, since the radial extension portion 36 is a non-magnetic and non-conductive material, leakage magnetic flux from the pole piece 50 to the radial extension portion 36 can be further suppressed, thereby suppressing eddy current loss in the pole piece unit 30.

[0044] FIG. 8 is a schematic diagram showing one axial end of the first yoke unit 10 according to an embodiment of the present disclosure. The non-magnetic material portion 16 has a base end portion 193 and a non-magnetic inner end portion 191 that protrudes radially inward from the base end portion 193. The non-magnetic inner end portion 191 is the radially inner end portion of the non-magnetic material portion 16. The axial length of the non-magnetic inner end portion 191 is shorter than the axial length of the base end portion 193. The magnetic material portion 18 has a base end portion 183 and a magnetic outer end portion 181 that protrudes radially outward from the base end portion 183. The base end portion 183 axially faces the first main body portion 11 across a gap G4. In the same figure, the radially outer portion of the gap G4 between the end plate 17 and the first main body portion 11 is closed by the non-magnetic material portion 16. The magnetic outer end portion 181 is the radially outer end portion of the magnetic material portion 18. The axial length of the magnetic outer end 181 is shorter than the axial length of the base end 183. The magnetic outer end 181 and the non-magnetic inner end 191 are arranged to be aligned in the axial direction. More specifically, the magnetic outer end 181 is located on the opposite side of the non-magnetic inner end 191 from the first body portion 11, and is in contact with the non-magnetic inner end 191. As a result, the non-magnetic inner end 191 faces and contacts the end face 11S of the first body portion 11. With the above configuration, the non-magnetic inner end 191 can face the first body portion 11, thereby preventing the first body portion 11 (particularly the radially outer end of the first body portion 11) from deforming toward the pole piece support 37. The non-magnetic inner end 191 may face the end face 11S across a gap G4 instead of contacting the end face 11S. In this case, the radially outer portion of the gap G4 is open, and the distance between the non-magnetic inner end 191 and the end face 11S is shorter than the distance between the magnetic material portion 18 and the end face 11S. Even in this case, the non-magnetic inner end 191 and the first body portion 11 come into contact immediately after the first body portion 11 starts to deform toward the pole piece support 37, thereby providing the advantage of suppressing deformation of the first body portion 11.

[0045] The first yoke 15 includes a plurality of steel plates 151 stacked in the axial direction. FIG. 9 is a schematic view of a steel plate 151 according to an embodiment, viewed in the axial direction. Each steel plate 151 has a plurality of opening edge portions 153 inside which the plurality of first magnets 19 are respectively arranged, and a covering portion 155 located radially outward of the plurality of opening edge portions 153. The covering portion 155 extends in the circumferential direction and is connected to each of the plurality of opening edge portions 153. FIG. 9 illustrates only one of the plurality of opening edge portions 153. Returning to FIG. 8, the non-magnetic material portion 16 has a contact portion 196, which contacts the covering portion 155 of the steel plate 151 located closest to the end plate 17.

[0046] Because a space is formed inside opening edge 153 in which each of the multiple first magnets 19 is disposed, covering portion 155 located radially outward of opening edge 153 has low rigidity in the axial direction. Therefore, covering portion 155 located closest to end plate 17 among the multiple steel plates 151 is prone to deformation toward end plate 17 in the axial direction. In this regard, with the above configuration, contact portion 196 of non-magnetic material portion 16 comes into contact with covering portion 155, thereby suppressing deformation of covering portion 155.

[0047] In some embodiments of the present disclosure, the contact portion 196 has a radial outer end 196A. The outer end 196A is positioned radially at the same position as the outer end 155A of the covering portion 155 or at a position more inward than the outer end 155A of the covering portion 155. With the above configuration, the outer end 196A of the contact portion 196 is not positioned radially outward of the first main body portion 11, which prevents the contact portion 196 from coming into contact with the pole piece unit 30 (more specifically, the pole piece 50 or the connecting portion 35). This prevents damage to the end plate 17 or the pole piece unit 30 when the magnetic gear 5 is operating.

[0048] In some embodiments of the present disclosure, the contact portion 196 of the non-magnetic material portion 16 has a contact surface 199 that contacts the covering portion 155. The contact surface 199 is located closer to the end surface 11S of the first main body portion 11 than the non-magnetic material portion 16 in the axial direction. With the above configuration, the contact surface 199 can actively contact the end surface 11S of the first main body portion 11 (more specifically, the end surface 11S that constitutes the covering portion 155). This makes it possible to more effectively suppress deformation of the covering portion 155.

[0049] <4. Magnetic-geared electric machine 1 incorporating magnetic gear 5> 10A to 10D, magnetic-geared electric machines 1 incorporating a magnetic gear 5 are illustrated. The magnetic-geared electric machines 1A and 1B (1) illustrated in FIGS. 10A and 10B are magnetic-geared generators 2A and 2B (2) configured to generate electricity by being driven by input from a prime mover 9, which is an example of an external rotating device. The magnetic-geared generator 2 is configured to supply the generated electric power P to a power supply destination 4, which may be, for example, a power grid. The magnetic-geared electric machines 1C and 1D (1) illustrated in FIGS. 10C and 10D are magnetic-geared motors 3A and 3B (3) configured to receive a supply of electric power P from a power supply source 6, which may be, for example, a power grid, and drive a rotating machine 8, which is an example of an external rotating device. The rotating machine 8 may be, for example, an electric vehicle that runs by being driven by the magnetic-geared motor 3. In this case, the rotation axis A of the magnetic-geared motor 3 may be coupled to a drive shaft of the electric vehicle, which is a component of the rotating machine 8. The magnetic-geared electric machines 1A and 1C illustrated in Figures 10A and 10C incorporate a magnetic gear 5A (see Figure 1A), and the magnetic-geared electric machines 1B and 1D illustrated in Figures 10B and 10D incorporate a magnetic gear 5B (see Figure 1B).

[0050] <4-1. Magnetic-geared generators 2A, 2B(2)> The magnetic-geared generators 2A, 2B (2) include a magnetic gear 5 and a coil 99 as a stator winding (armature winding). The coil 99 of the magnetic-geared generator 2A is wound around teeth 28 provided on the second yoke unit 20. The coil 99 can be electrically connected to a power supply destination 4.

[0051] The magnetic-geared generator 2A illustrated in Fig. 10A operates, for example, as follows. When the prime mover 9 connected to the first rotating shaft A1, which functions as the input shaft in the figure, is driven, the first yoke unit 10 rotates according to the principle already described. As a result, a current is generated in the coil 99 due to electromagnetic induction that occurs as the pole piece unit 30 and the first yoke unit 10 rotate. This enables the magnetic-geared generator 2A to generate electricity.

[0052] The operating principle of the magnetic-geared generator 2B illustrated in Fig. 10B is similar to that of the magnetic-geared generator 2A. When the prime mover 9 connected to the second rotating shaft A2, which functions as the input shaft in the figure, is driven, the first yoke unit 10 rotates, and according to the principle already described, the second yoke unit 20 rotates. As a result, a current is generated in the coil 99 due to electromagnetic induction that occurs as the first yoke unit 10 and the second yoke unit 20 rotate. This enables the magnetic-geared generator 2B to generate electricity.

[0053] <4-2. Magnetic geared motor 3A, 3B(3)> The magnetic-geared motors 3A, 3B (3) include a magnetic gear 5 and a coil 99 as a stator winding (armature winding). The coil 99 of the magnetic-geared motors 3A, 3B (3) is wound around teeth 28 provided on the second yoke unit 20. The coil 99 can be electrically connected to the power supply source 6.

[0054] The magnetic-geared motor 3A illustrated in Fig. 10C operates, for example, as follows. The first yoke unit 10 is energized by a rotating magnetic field generated by energizing the coil 99. When the first yoke unit 10 rotates together with the second rotating shaft A2, the pole piece unit 30 rotates according to the principle described above. In the example shown in the figure, the first rotating shaft A1 functions as the output shaft and drives the rotating machine 8.

[0055] The operating principle of the magnetic-geared motor 3B illustrated in Fig. 10D is similar to that of the magnetic-geared motor 3A. The second yoke unit 20 is energized by a rotating magnetic field generated by energizing the coil 99. When the second yoke unit 20 rotates together with the first rotating shaft A1, the first yoke unit 10 rotates according to the principle described above. In the example shown in Fig. 10D, the second rotating shaft A2, which functions as the output shaft, drives the rotating machine 8.

[0056] As already mentioned, the magnetic-geared generator 2 does not have to have the first rotating shaft A1 or the second rotating shaft A2 functioning as the output shaft, and the magnetic-geared motor 3 does not have to have the first rotating shaft A1 or the second rotating shaft A2 functioning as the input shaft.

[0057] <5. Summary> The contents of the above-described embodiments can be understood, for example, as follows.

[0058] 1) The magnetic gear (5) according to at least one embodiment of the present disclosure is a first yoke unit (10) including a first body portion (11) having a plurality of first magnets (19) arranged in a circumferential direction about an axis (Q) and a first yoke (15) supporting the plurality of first magnets; a second yoke unit (20) including a plurality of second magnets (29) arranged in the circumferential direction on the outer circumferential side of the first yoke unit; a pole piece unit (30) including a plurality of pole pieces (50) arranged in the circumferential direction between the first yoke unit and the second yoke unit; A magnetic gear comprising: The pole piece unit further includes a pole piece support (37) having a connecting portion (35) connected to an end of each of the plurality of pole pieces and a radial extending portion (36) extending radially inward from the connecting portion; the first yoke unit further includes an end plate (17) that is arranged on an end surface of the first main body portion in the axial direction and faces the radially extending portion with a predetermined gap (G3) in the axial direction, The end plate is a magnetic portion (18) formed of a magnetic material; a non-magnetic material portion (19) formed of a non-magnetic material and disposed radially outward of the magnetic material portion; It has.

[0059] According to the configuration of 1) above, at least a portion of the leakage magnetic flux generated between the first yoke unit and the second yoke unit is induced to the magnetic material portion of the end plate. This prevents the leakage magnetic flux from flowing through the pole piece support, reducing eddy current loss in the pole piece support. Furthermore, a non-magnetic material portion is disposed radially outward of the magnetic material portion, and this non-magnetic material portion is close to one end of the pole piece in the axial direction. Because the magnetic flux tends to flow so as to avoid the non-magnetic material portion, the occurrence of leakage magnetic flux passing through the pole piece in the axial direction can be reduced. As a result, a magnetic gear is realized that suppresses eddy current loss in the pole piece unit due to the occurrence of leakage magnetic flux.

[0060] 2) In some embodiments, the magnetic gear according to 1) above, A boundary (33) between the magnetic material portion and the non-magnetic material portion is located radially outward of an inner peripheral surface (19A) of each of the first magnets.

[0061] According to the configuration 2), the magnetic material portion is close to the pole piece, which makes it easier for leakage magnetic flux generated in the pole piece to be guided to the magnetic material portion, thereby further suppressing eddy current loss in the pole piece unit.

[0062] 3) In some embodiments, the magnetic gear according to 1) or 2) above, When the dimension of the non-magnetic material portion in the radial direction is L and the distance in the radial direction between the pole piece and the first yoke unit is R, the relationship R≦L≦6×R is satisfied.

[0063] According to the configuration of 3) above, since the relationship L≦6×R is satisfied, the magnetic material portion is prevented from being too far away from the pole piece, and short-circuiting of magnetic flux between the pole piece and the magnetic material portion can be suppressed. Furthermore, since the relationship R≦L is satisfied, the minimum size of the non-magnetic material portion can be secured, and leakage flux at the pole piece can be suppressed.

[0064] 4) In some embodiments, the magnetic gear according to any one of 1) to 3) above, When the dimension of the magnetic material portion in the axial direction is D and the distance in the axial direction between the radially extending portion and the first main body portion is S, the relationship D≧0.15×S is satisfied.

[0065] According to the configuration of 4) above, the relationship D≧0.15×S is satisfied, which prevents the magnetic material portion from becoming too short in the axial direction, and suppresses short-circuiting of magnetic flux between the pole piece and the magnetic material portion.

[0066] 5) In some embodiments, the magnetic gear according to any one of 1) to 4) above, The radially extending portion is made of a non-magnetic material.

[0067] According to the above configuration 5), the radially extending portion is made of a non-magnetic material, which further suppresses leakage flux from the pole piece to the radially extending portion, thereby suppressing eddy current loss in the pole piece unit.

[0068] 6) In some embodiments, the magnetic gear according to 5) above, The radially extending portion is formed from a non-conductive material.

[0069] According to the configuration 6) above, since the radially extending portion is made of a non-conductive material, leakage flux from the pole piece to the radially extending portion can be further suppressed, thereby suppressing eddy current loss in the pole piece unit.

[0070] 7) In some embodiments, the magnetic gear according to any one of 1) to 6) above, The non-magnetic material portion has a non-magnetic inner end portion (191) that is an inner end portion in the radial direction, The magnetic material portion has a magnetic outer end portion (181) which is the outer end portion in the radial direction, and which is located on the opposite side of the first main body portion from the non-magnetic inner end portion and which contacts the non-magnetic inner end portion.

[0071] According to the above configuration 7), the non-magnetic inner end portion can face the first main body portion, so that deformation of the first main body portion toward the pole piece support body can be suppressed.

[0072] 8) In some embodiments, the magnetic gear according to any one of 1) to 7) above, The first yoke includes a plurality of steel plates (151) stacked in the axial direction, Each of the steel plates comprises: a plurality of opening edge portions (153) inside which the plurality of first magnets are respectively arranged; a covering portion (155) positioned radially outward of each of the plurality of opening edge portions; and The non-magnetic material portion has a contact portion (196) that contacts the covering portion of the steel plate that is located closest to the end plate.

[0073] Because a space in which the first magnet is disposed is formed inside the opening edge, the covering portion located radially outward of the opening edge has low axial rigidity. Therefore, the covering portion located closest to the end plate among the multiple steel plates is prone to axial deformation. In this regard, with the configuration of 8) above, the contact portion of the non-magnetic material portion comes into contact with the covering portion, thereby suppressing deformation of the covering portion.

[0074] 9) In some embodiments, the magnetic gear according to 8) above, In the radial direction, the outer end (196A) of the contact portion is disposed at the same position as the outer end of the covering portion or at a position more inward than the outer end of the covering portion.

[0075] According to the configuration of 9), the outer end of the contact portion is not positioned radially outward of the first main body portion, which prevents the contact portion from coming into contact with the pole piece unit, thereby preventing damage to the end plate or the pole piece unit when the magnetic gear is operating.

[0076] 10) In some embodiments, the magnetic gear according to 8) or 9) above, The contact portion of the non-magnetic material portion has a contact surface (199) that contacts the covering portion and is located closer to the end face of the first main body portion in the axial direction than the magnetic material portion.

[0077] According to the above configuration 10), the contact surface can be brought into active contact with the first main body portion, thereby more effectively suppressing deformation of the covering portion.

[0078] 11) In some embodiments, the magnetic gear according to any one of 1) to 10) above, The non-magnetic material forming the non-magnetic portion is non-conductive.

[0079] According to the configuration 11) above, even when leakage magnetic flux interlinks the non-magnetic material portion formed of a non-magnetic material, eddy current loss in the non-magnetic material portion can be suppressed.

[0080] 12) A magnetic-geared electric machine (1) according to at least one embodiment of the present disclosure includes: A magnetic gear (5) according to any one of 1) to 11) above, a coil (99) provided on a second yoke (25) that supports the second magnet; A rotating shaft (A) for transmitting torque between an external rotating device (rotating machine 8, prime mover 9) and the magnetic gear; Equipped with.

[0081] According to the configuration of 12) above, for the same reason as in 1), a magnetic-geared electric machine in which eddy current loss in the pole piece unit is suppressed is realized.

[0082] The above describes embodiments of the present disclosure, but the present disclosure is not limited to the above-described embodiments, and also includes forms in which the above-described embodiments are modified, or forms in which these forms are appropriately combined.

[0083] In this specification, expressions expressing relative or absolute arrangement such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial" not only express such an arrangement strictly, but also express a state in which there is a relative displacement with a tolerance or an angle or distance to the extent that the same function is obtained. For example, expressions such as "identical," "equal," and "homogeneous" that indicate that something is in an equal state not only indicate a state of strict equality, but also indicate a state in which there is a tolerance or a difference to the extent that the same function is obtained. Furthermore, in this specification, expressions representing shapes such as a rectangular shape or a cylindrical shape not only represent rectangular shapes or cylindrical shapes in the strict geometric sense, but also represent shapes including uneven portions, chamfered portions, etc., to the extent that the same effect can be obtained. Furthermore, in this specification, the expressions "comprise," "include," or "have" a component are not exclusive expressions that exclude the presence of other components. [Explanation of symbols]

[0084] 1: Magnetic-geared electric machine 5: Magnetic gear 10: First yoke unit 11: First main body part 11S: End face 15: First yoke 16: Non-magnetic material part 17: End plate 18:Magnetic material part 19: First magnet 19A: Inner surface 20: Second yoke unit 25: Second yoke 29: Second magnet 30: Pole piece unit 33: Boundary 35:Connection part 36: Radial extension part 37: Magnetic pole piece support 50 :Pole piece 99: Coil 151: Steel plate 153: Opening edge 155: Covering part 155A: Outer end 181:Magnetic outer end 191: Non-magnetic inner end 196: Contact part 196A: Outer end 199: Contact surface D: Dimensions G1: First gap L: Dimensions Q: Axis line R: Distance S: distance

Claims

1. a first yoke unit including a first body portion having a plurality of first magnets arranged in a circumferential direction about an axis and a first yoke supporting the plurality of first magnets; a second yoke unit including a plurality of second magnets arranged in the circumferential direction on an outer circumferential side of the first yoke unit; a pole piece unit including a plurality of pole pieces arranged in the circumferential direction between the first yoke unit and the second yoke unit; A magnetic gear comprising: the pole piece unit further includes a pole piece support having a connecting portion connected to an end of each of the plurality of pole pieces and a radial extending portion extending radially inward from the connecting portion; the first yoke unit further includes an end plate disposed on an end surface of the first main body portion in the axial direction, the end plate facing the radially extending portion with a predetermined gap in the axial direction, The end plate is a magnetic portion formed of a magnetic material; a non-magnetic material portion formed of a non-magnetic material and disposed radially outward of the magnetic material portion; having Magnetic gear.

2. a boundary between the magnetic material portion and the non-magnetic material portion is located radially outward of an inner circumferential surface of each of the first magnets; The magnetic gear according to claim 1 .

3. where L is the dimension of the non-magnetic material portion in the radial direction and R is the distance in the radial direction between the pole piece and the first yoke unit, the relationship R≦L≦6×R is satisfied. The magnetic gear according to claim 1 or 2.

4. When the dimension of the magnetic material portion in the axial direction is D and the distance in the axial direction between the radially extending portion and the first main body portion is S, a relationship of 0.15×S≦D<S is satisfied. The magnetic gear according to claim 1 or 2.

5. The radially extending portion is formed of a non-magnetic material. The magnetic gear according to claim 1 or 2.

6. the radially extending portion is formed of a non-conductive material; The magnetic gear according to claim 5 .

7. the non-magnetic material portion has a non-magnetic inner end portion that is an inner end portion in the radial direction, the magnetic material portion has a magnetic outer end portion that is an outer end portion in the radial direction, the magnetic outer end portion being located on the opposite side of the first main body portion with respect to the non-magnetic inner end portion and in contact with the non-magnetic inner end portion; The magnetic gear according to claim 1 or 2.

8. the first yoke includes a plurality of steel plates stacked in the axial direction, Each of the steel plates comprises: a plurality of opening edge portions, inside which the plurality of first magnets are respectively arranged; a covering portion located radially outward of each of the plurality of opening edge portions; and the non-magnetic material portion has a contact portion that contacts the covering portion of the steel plate that is located closest to the end plate, The magnetic gear according to claim 1 .

9. In the radial direction, an outer end of the contact portion is disposed at the same position as an outer end of the covering portion or at a position more inward than the outer end of the covering portion. The magnetic gear according to claim 8.

10. the contact portion of the non-magnetic material portion has a contact surface that comes into contact with the covering portion and is located closer to the end face of the first main body portion in the axial direction than the magnetic material portion. The magnetic gear according to claim 8 or 9.

11. the non-magnetic material forming the non-magnetic portion is non-conductive; The magnetic gear according to claim 1 or 2.

12. The magnetic gear according to claim 1 or 2; a coil provided on a second yoke supporting the second magnet; a rotating shaft for transmitting torque between an external rotating device and the magnetic gear; 1. A magnetic-geared electric machine comprising:

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