JP7749488B2 - Magnetic-Geared Electric Machines - Google Patents

Description

This disclosure relates to magnetic-geared electric machines.

Conventionally, motors configured to cool the inside of the housing are known. For example, the motor disclosed in Patent Document 1 has a rotating shaft on which a fan for cooling the inside of the motor is mounted.

JP 2010-077841 A

When the above-mentioned cooling fan is installed in a magnetic-geared electric machine, in which multiple components for transmitting magnetic power can be kept out of contact with each other, the magnet rotor and the fan are positioned apart by an end plate attached to one end of the pole piece rotor. Therefore, if a mechanism is used to mechanically link the two components in order to rotate the cooling fan in conjunction with the magnet rotor, this could lead to a complex configuration of the magnetic-geared electric machine.

The objective of this disclosure is to provide a magnetic-geared electric machine with a simple configuration that rotates a cooling fan in conjunction with a magnet rotor.

A magnetic-geared electric machine according to at least one embodiment of the present disclosure comprises:
a magnetic gear unit including a stator, a pole piece rotor disposed radially opposite the stator, a first rotor including a plurality of magnets positioned on the opposite side of the stator in the radial direction across the pole piece rotor, and an end plate disposed on one side of the first rotor in the axial direction and connected to one end of the pole piece rotor;
a second rotor including a cooling fan and disposed on the opposite side of the first rotor in the axial direction with the end plate interposed therebetween;
The magnetic torque transmission unit includes a first magnet provided on the first rotor and a second magnet provided on the second rotor so as to be positioned on the opposite side of the end plate from the first magnet.

This disclosure provides a magnetic-geared electric machine with a simple configuration that rotates a cooling fan in conjunction with a magnet rotor.

FIG. 1 is a schematic diagram illustrating an example of a magnetic-geared electric machine. FIG. 1 is a schematic diagram illustrating another example of a magnetic-geared electric machine. 1 is a radial cross-sectional view of a magnetic-geared electric machine according to an embodiment; 1 is an axial cross-sectional view of a magnetic-geared electric machine according to an embodiment; FIG. 2 is a schematic diagram illustrating an example of a magnetic torque transmitting unit. FIG. 4 is a schematic view showing a first end plate as viewed in an axial direction according to one embodiment. 6 is a schematic diagram showing a cross section of the first end plate taken along the line AA in FIG. 5 . FIG. 10 is a schematic diagram showing another example of a magnetic torque transmission unit.

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

(Overview of magnetic-geared electric machines)
1A and 1B are schematic diagrams showing an example of a magnetic-geared electric machine 10. In Fig. 1A and 1B, the "axial direction" is a direction parallel to a rotating shaft 35 of the magnetic-geared electric machine 10, the "radial direction" is a direction perpendicular to the rotating shaft 35, and the "circumferential direction" is a circumferential direction based on the rotating shaft 35. Power is transmitted between the magnetic-geared electric machine 10 and an external device 7.
In one embodiment, as shown in FIG. 1A , the magnetic-geared electric machine 10 is a magnetic-geared generator 10A configured to generate electricity using power transmitted (input) from an external device 7A (7) serving as a prime mover, and to supply the generated electric power P to an electric power supply destination 4, which may be, for example, an electric power grid.
In another embodiment, as shown in FIG. 1B , the magnetic-geared electric machine 10 is a magnetic-geared motor 10B configured to receive power P from a power supply source 6, which may be, for example, a power grid, and transmit (output) power to an external device 7B (7) as a drive unit.

1A, the magnetic-geared generator 10A constitutes a part of a power generation system 1. The power generation system 1 may be, for example, a renewable energy power generation system such as a wind power generation system or a tidal power generation system. When the power generation system 1 is a wind power generation system, the shaft 3A (3) included in the external device 7A as a prime mover is a wind turbine rotor.
The magnetic-geared generator 10A includes a magnetic gear unit 5. The magnetic gear unit 5 includes a stator 20 including a stator magnet 22 and a stator coil 24, a pole piece rotor 30 including a plurality of pole pieces 32 arranged radially opposite the stator 20, and a first rotor (magnet rotor) 110 including a plurality of magnets 42 located on the radially opposite side of the pole piece rotor 30 from the stator 20. In the example of Fig. 1A, the plurality of pole pieces 32 are arranged radially inward from the stator 20, and the first rotor 110 is arranged radially inward from the plurality of pole pieces 32. The stator 20 is arranged inside a housing 21.
The magnetic gear unit 5 includes a pair of end plates 34 connected to both axial ends of the pole piece rotor 30, and a rotating shaft 35 connected to the shaft 3A of the external device 7A, and the pair of end plates 34 are connected to the rotating shaft 35. Therefore, when torque is input from the shaft 3A of the external device 7A to the rotating shaft 35, the pole piece rotor 30 rotates integrally with the shaft 3A. In this example, the rotating shaft 35 is rotatably supported by the housing 21 via bearings B1 and B2.
The first rotor 110 includes a core 46 provided with a plurality of magnets 42, and bearings B3 and B4 that connect the core 46 to the rotating shaft 35. The core 46 can rotate relative to the rotating shaft 35.

The magnetic-geared generator 10A described above converts mechanical input from the external device 7A into electric power by utilizing the harmonic magnetic gear principle and electromagnetic induction.
For example, power generation in the magnetic-geared generator 10A may be performed based on the following principle: The magnetic flux of the stator magnet 22 is modulated by the pole pieces 32 of the pole piece rotor 30, which rotates together with the shaft 3A of the external device 7A, and the magnet 42 receives a magnetic force from the modulated magnetic field, causing the first rotor 110 to rotate. At this time, the ratio of the rotation speed of the first rotor 110 to that of the pole piece rotor 30 (speed-up ratio) is expressed as the ratio of the number of magnetic poles NL of the pole pieces 32 to the number of pole pairs NH of the magnet 42 (=NL/NH). As the first rotor 110 rotates, a current is generated in the stator coil 24 by electromagnetic induction.
1A, the magnetic gear unit 5 has a configuration in which the stator 20, the pole piece rotor 30, and the first rotor 110 are arranged in this order from the outside in the radial direction. In another embodiment, the magnetic-geared generator 10A has a configuration in which the first rotor 110, the pole piece rotor 30, and the stator 20 are arranged in this order from the outside in the radial direction. In this case, the first rotor 110, the pole piece rotor 30, and the stator 20 are arranged inside the cylindrical shaft 3A.

1B, the magnetic-geared motor 10B constitutes part of the drive system 2. The drive system 2 operates using the magnetic-geared motor 10B as a drive source. As an example, the drive system 2 may be a vehicle that runs using the magnetic-geared motor 10B as a power source. In this case, the shaft 3B(3) included in the external device 7B is a drive shaft for transmitting power to the wheels.
The magnetic-geared motor 10B has a basic configuration common to that of the magnetic-geared generator 10A shown in FIG. 1A.
That is, the magnetic-geared motor 10B includes a magnetic gear unit 5. The magnetic gear unit 5 includes a stator 20 including a stator magnet 22 and a stator coil 24, a pole piece rotor 30 including a plurality of pole pieces 32 arranged radially opposite the stator 20, and a first rotor (magnet rotor) 110 including a plurality of magnets 42 located on the radially opposite side of the pole piece rotor 30 from the stator 20. In the example of Fig. 1B, the plurality of pole pieces 32 are arranged radially inward from the stator 20, and the first rotor 110 is arranged radially inward from the plurality of pole pieces 32. The stator 20 is arranged inside a housing 21.
The magnetic gear unit 5 includes a pair of end plates 34 connected to both axial ends of the pole piece rotor 30, and a rotating shaft 35 connected to the shaft 3B of the external device 7B, and the pair of end plates 34 are connected to the rotating shaft 35. Therefore, when torque is input from the shaft 3B of the external device 7B to the rotating shaft 35, the pole piece rotor 30 rotates integrally with the shaft 3B. In this example, the rotating shaft 35 is rotatably supported by the housing 21 via bearings B1 and B2.
The first rotor 110 includes a core 46 provided with a plurality of magnets 42, and bearings B3 and B4 that connect the core 46 to the rotating shaft 35. The core 46 can rotate relative to the rotating shaft 35.

The magnetic-geared motor 10B is a combination of a magnetic gear and a motor, and rotates the first rotor 110 using a rotating magnetic field generated by energizing the stator coil 24, and power is transmitted from the first rotor 110 to the pole piece rotor 30 using the principle of harmonic magnetic gears.
1B, the magnetic gear unit 5 has a configuration in which the stator 20, the pole piece rotor 30, and the first rotor 110 are arranged in this order from the outside in the radial direction. In another embodiment, the magnetic gear unit 5 has a configuration in which the first rotor 110, the pole piece rotor 30, and the stator 20 are arranged in this order from the outside in the radial direction. In this case, the first rotor 110, the pole piece rotor 30, and the stator 20 are arranged inside the cylindrical shaft 3B.

(Internal structure of a magnetic-geared electric machine)
Next, the internal structure of the magnetic-geared electric machine 10 (10A, 10B) described above will be described with reference to FIG.
FIG. 2 is a radial cross-sectional view of a magnetic-geared electric machine 10 according to one embodiment.
2 , the stator 20 of the magnetic-geared electric machine 10 includes a plurality of stator magnets 22 arranged in the circumferential direction and a plurality of stator coils 24. The stator magnets 22 and the stator coils 24 are attached to a stator core 23.

The stator magnets 22 are made of permanent magnets and are provided in multiple numbers circumferentially so as to pass axially between the stator coils 24 and the pole piece rotors 30 in the radial direction. In the example shown in Fig. 2, each stator magnet 22 is a rod-shaped member that is elongated in the axial direction and has a rectangular cross section. That is, the dimensions of each side of the rectangular cross section of the stator magnet 22 shown in Fig. 2 are sufficiently smaller than the axial dimensions of the stator magnets 22 shown in Figs. 1A and 1B.
2 shows an example of a surface permanent magnet (SPM) structure in which the stator magnet 22 is attached to the surface of the stator core 23. In other embodiments, the stator 20 may have an interior permanent magnet (IPM) structure in which the stator magnet 22 is embedded in the stator core 23.

The stator coils 24 are arranged in multiple slots 25 provided in the stator core 23. The multiple slots 25 are arranged in the circumferential direction, and each slot 25 extends in the axial direction. Both axial ends of each slot 25 are open, and the coil end portions of the stator coils 24 that do not fit into the slots 25 may protrude from the stator core 23 at both axial ends of the stator core 23.

The pole piece rotor 30, which radially faces the stator 20 configured as described above, is disposed with a first radial gap G1 between it and the stator 20 and includes a plurality of pole pieces 32 arranged circumferentially. Each pole piece 32 is made of a magnetic material such as an electromagnetic steel plate or a powder magnetic core, and is a rod-shaped member that is elongated in the axial direction and has a rectangular cross section. In other words, the dimensions of each side of the rectangular cross section of the pole piece 32 shown in Figure 2 are sufficiently smaller than the axial dimensions of the pole piece 32 shown in Figures 1A and 1B.

In addition to the pole pieces 32, the pole piece rotor 30 may also include other components such as a non-magnetic member 33 (see Figure 2) made of a non-magnetic material that connects the pole pieces 32 circumferentially, and the end plate 34 described above with reference to Figures 1A and 1B.
The non-magnetic member 33 may be a fiber-reinforced plastic (FRP) in which reinforcing fibers are combined with a matrix resin, such as CFRP in which carbon fibers are used as reinforcing fibers or GFRP in which glass fibers are used as reinforcing fibers.

As shown in FIG. 2, the first rotor 110 is provided radially inward of the multiple pole pieces 32, separated by a second radial gap G2. Note that the first radial gap G1 between the stator 20 and the pole piece rotor 30 and the second radial gap G2 between the pole piece rotor 30 and the first rotor 110 may be approximately the same size.

The first rotor 110 includes a plurality of magnets 42, each of which is a permanent magnet, arranged in the circumferential direction. Each of the magnets 42 may be a rod-shaped member that is elongated in the axial direction and has a rectangular cross section.
2 shows an example of a surface permanent magnet (SPM) structure in which the magnets 42 are attached to the surface of the core 46. In other embodiments, the first rotor 110 may have an interior permanent magnet (IPM) structure in which the magnets 42 are embedded in the core 46.

In addition to the magnets 42 and the core 46, the first rotor 110 may include other members such as blocking members 45 (see FIG. 2) that fill circumferential gaps between the magnets 42.
The blocking member 45 may also be a fiber-reinforced plastic (FRP) made by compounding reinforcing fibers with a matrix resin, such as CFRP using carbon fibers as reinforcing fibers or GFRP using glass fibers as reinforcing fibers. The blocking member 45 may block at least a portion of the circumferential gap between the magnet groups (Gr1, Gr2) arranged alternately in the circumferential direction, as shown in FIG. 2 . In this case, the height from the core 46 to the surface of the blocking member 45 may be smaller than the protruding height of each magnet 42 from the core 46.

In the exemplary embodiment shown in FIG. 2, the components in order of quantity are stator coils 24, magnets 42, pole pieces 32, and stator magnets 22.

(Outline of cooling structure of magnetic-geared electric machine 10)
In the magnetic-geared electric machine 10 (10A, 10B) configured as described above, heat may be generated due to copper loss in the stator coil 24 and iron loss in the pole pieces 32, or heat may accumulate inside the magnetic-geared electric machine 10. Therefore, a cooling structure is adopted in the magnetic-geared electric machine 10. An overview of this structure will be described below.
3 is an axial cross-sectional view showing the internal structure of the magnetic-geared electric machine 10 according to one embodiment. In the following description, of the pair of end plates 34 described above, the end plate 34 arranged on one side of the first rotor 110 in the axial direction may be referred to as the first end plate 34A, and the other end plate 34 may be referred to as the second end plate 34C. The first end plate 34A and the second end plate 34C may have different shapes.

In some embodiments, the magnetic-geared electric machine 10 includes a second rotor 120 that is arranged axially opposite the first rotor 110 across the first end plate 34A. The second rotor 120 includes a cooling fan 127 that is rotatably supported by the rotating shaft 35 via a bearing B5. Therefore, the second rotor 120 including the cooling fan 127 is rotatable relative to the rotating shaft 35. In this example, multiple cooling fans 127 are arranged at equal intervals along the circumferential direction.

In this example, the second rotor 120 rotates when the torque of the first rotor 110 is transmitted by the magnetic torque transmission unit 15. The magnetic torque transmission unit 15, which is a component of the magnetic-geared electric machine 10, includes a first magnet 11A (11) provided on the first rotor 110 and a second magnet 12A (12) provided on the second rotor 120. The second magnet 12A is located on the opposite side of the first end plate 34A from the first magnet 11A. The first magnet 11A and the second magnet 12A, which are arranged across the first end plate 34A, are magnetically coupled, allowing the second rotor 120 to rotate in conjunction with the rotation of the first rotor 110. As the cooling fan 127 rotates, cooling air flows inside the housing 21, cooling the magnetic-geared electric machine 10.
In this embodiment, the plurality of first magnets 11A are arranged in the circumferential direction, and the plurality of second magnets 12A are also arranged in the circumferential direction. The first magnets 11A may be provided on one axial end face 115 of the first rotor 110. The second magnets 12A may be provided on the support plate 17 located on the other axial side of the cooling fan 127.

The magnetic torque transmission unit 15 illustrated in FIG. 3 is a magnetic coupling, and the number of first magnets 11A is the same as the number of second magnets 12A. More specifically, the magnetic torque transmission unit 15 is a disk-type magnetic coupling (planar magnetic coupling) in which multiple first magnets 11A and multiple second magnets 12A each face the first end plate 34A in the axial direction. Each of the multiple first magnets 11A is magnetically coupled to one of the multiple second magnets 12A, and the first rotor 110 and the second rotor 120 rotate while maintaining their respective magnetic couplings. Therefore, the rotational speeds of the first rotor 110 and the second rotor 120 are approximately the same.

10 illustrates a flow path of cool air from a cooling fan 127 according to an embodiment of the present disclosure.
3 includes a first passage wall 221, a second passage wall 222 located radially inward of the first passage wall 221, and a support wall 223 that supports the stator 20 radially inward of the second passage wall 222. A ventilation hole 221A is formed in the first passage wall 221. The first passage wall 221 and the second passage wall 222 define an outer ventilation passage 231 that communicates with a space So outside the magnetic-geared electric machine 10 via the ventilation hole 221A, the second passage wall 222 and the support wall 223 define an inner ventilation passage 232, and the support wall 223 defines an inner space Si in which the magnetic gear unit 5 is disposed.
The cooling fan 127 illustrated in the figure has a first cooling fan 121 and a second cooling fan 122 that are integrally formed with each other, and the first cooling fan 121 is located on one axial side of the second cooling fan 122. The first cooling fan 121 has a first inlet 121A and a first outlet 121B that is located radially outward of the first inlet 121A. As the cooling fan 127 rotates, cooling air flows from the ventilation opening 221A into the first inlet 121A, passing through the first outlet 121B and the external ventilation passage 231 in that order, and then flows into the external space So (see the solid arrow).
The second cooling fan 122 also has a second inlet 122A and a second outlet 122B located radially outward of the second inlet 122A. As the cooling fan 127 rotates, cooling air flows from the inner space Si into the second inlet 122A, passes through the second outlet 122B and the inner ventilation passage 232, returns to the inner space Si, and flows through the magnetic gear unit 5 (see the dashed arrows). The cooling air flowing through the magnetic gear unit 5 includes the cooling air that enters the first radial gap G1 and the cooling air that enters the second radial gap G2 through the ventilation opening 36 provided in the second end plate 34C. The cooling air flowing through the inner ventilation passage 232 is cooled by heat exchange with the cooling air flowing through the outer ventilation passage 231, thereby enhancing the cooling effect in the inner space Si.
In the illustrated embodiment, the second cooling fan 122 is longer in the radial direction than the first cooling fan 121, and at least a portion of the second inlet 122A is located radially inward of the first inlet 121A.

With the above configuration, the magnetic torque transmission unit 15 can magnetically couple the first rotor 110, which serves as a magnet rotor, to the second rotor 120, which is disposed across the first end plate 34A from the first rotor 110. This allows the cooling fan 127 to rotate in conjunction with the rotation of the first rotor 110, which serves as a magnet rotor. Because there is no need to mechanically couple the first rotor 110 and the second rotor 120, the configuration of the magnetic-geared electric machine 10 can be simplified. As described above, a magnetic-geared electric machine 10 with a simple configuration that rotates the cooling fan 127 in conjunction with the magnet rotor is realized.

In another embodiment, the magnetic torque transmission unit 15 may be a magnetic gear instead of a magnetic coupling. In this case, multiple pole pieces may be rotatably arranged between the multiple first magnets 11A and the multiple second magnets 12A, and the number of first magnets 11A and the number of second magnets 12A may be different. Furthermore, the magnetic torque transmission unit 15 may be an in-out type magnetic coupling (coaxial magnetic coupling) instead of a disk type magnetic coupling (details will be described later using Figure 7). Furthermore, an external ventilation passage 231 may be formed in the housing 21, and the cooling fan 127 may not have a first cooling fan 121. Furthermore, the housing 21 may not be provided with a vent 221A, and the internal space Si of the housing 21 may be an enclosed space. In any of these embodiments, the magnetic torque transmission unit 15 can rotate the cooling fan 127 in conjunction with the rotation of the first rotor 110, eliminating the need to mechanically couple the first rotor 110 and the second rotor 120. This provides a magnetic-geared electric machine 10 with a simple configuration that rotates the cooling fan 127 in conjunction with the magnet rotor.

Furthermore, in an embodiment in which the magnetic torque transmission unit 15 is a magnetic coupling, the configuration of the magnetic torque transmission unit 15 can be simplified compared to, for example, a case in which the magnetic torque transmission unit 15 is a magnetic gear that includes multiple pole pieces in addition to the first magnet 11A and the second magnet 12A.

Furthermore, if the magnetic torque transmission unit 15 is configured as a disk-type magnetic coupling, the first end plate 34A located between the first magnet 11A and the second magnet 12A can be configured to extend radially, thereby making it possible to compact the axial placement space of the first end plate 34A.
Since the first end plate 34A can be configured to extend in the radial direction, the shape of the first end plate 34A can be simplified and the strength of the first end plate 34A can be ensured.

Furthermore, in the embodiment illustrated in Figures 2 and 3, the number of pole pairs NH of the multiple magnets 42 of the first rotor 110 is less than the number of magnetic poles NL of the multiple magnetic pole pieces 32. As described above, the ratio of the rotation speed of the first rotor 110 to the magnetic pole piece rotor 30 (speed-up ratio) is expressed as NL/NH. Therefore, in this embodiment, the speed-up ratio is greater than 1, and the first rotor 110 rotates faster than the magnetic pole piece rotor 30, thereby increasing the airflow rate of the cooling fan 127 linked to the first rotor 110. This allows the magnetic-geared electric machine 10 to achieve improved cooling performance.

(Example of details of a magnetic torque transmission unit according to an embodiment)
FIG. 4 is a schematic diagram illustrating a magnetic torque transmitting unit 15 according to one embodiment of the present disclosure.
The first end plate 34A according to some embodiments of the present disclosure includes a recess 60A (60) extending circumferentially and facing at least one of the first magnet 11A (11) and the second magnet 12A (12). In this example, the recess 60A (60) is formed in a ring shape when viewed in the axial direction and faces at least one of the first magnet 11A or the second magnet 12A in the axial direction. The recess 60A is recessed toward the axial center of the first end plate 34A.
The recess 60A (60) illustrated in the figure has a first recess 61A (61) facing the first magnet 11A and a second recess 62A (62) facing the second magnet 12A. The first magnet 11A is positioned so that it at least partially enters the first recess 61A, and the second magnet 12A is also positioned so that it at least partially enters the second recess 62A.
When a portion of the first magnet 11A overlaps with the first recess 61A in the axial and radial directions, the first magnet 11A is understood to partially intrude into the first recess 61A. In other words, when a portion of the first magnet 11A overlaps with the first recess 61A in the axial direction within a predetermined radial range, the first magnet 11A is understood to partially intrude into the first recess 61A. Furthermore, when a portion of each of the multiple first magnets 11A is located inside the first recess 61A, each first magnet 11A is understood to partially intrude into the first recess 61A.
On the other hand, when the entire first magnet 11A overlaps with the first recess 61A in the axial and radial directions, it is understood that the entire first magnet 11A enters the first recess 61A. In other words, when the entire first magnet 11A overlaps with the first recess 61A in the axial direction within a predetermined radial range, it is understood that the entire first magnet 11A enters the first recess 61A. Furthermore, when the entirety of each of the multiple first magnets 11A is located inside the first recess 61A, it is understood that the entirety of each first magnet 11A enters the first recess 61A.
Similarly, when a portion of the second magnet 12A overlaps with the second recess 62A in the axial and radial directions, it is understood that the second magnet 12A partially intrudes into the second recess 62A. Furthermore, when the entire second magnet 12A overlaps with the second recess 62A in the axial and radial directions, it is understood that the entire second magnet 12A intrudes into the second recess 62A.

According to the above configuration, at least one of the first magnet 11A and the second magnet 12A is disposed inside the recess 60A, thereby shortening the distance between the first magnet 11A and the second magnet 12A. Since the magnetic coupling force between the first magnet 11A and the second magnet 12A is increased, the magnetic torque transmission unit 15 can efficiently transmit the torque of the first rotor 110 to the second rotor 120.
Note that if either the first magnet 11A or the second magnet 12A is arranged so that it at least partially enters the recess 60A, the distance between the first magnet 11A and the second magnet 12A can be shortened. Therefore, the above-described advantages can be obtained even in an embodiment in which the recess 60A has only one of the first recess 61A or the second recess 62A.

Furthermore, by configuring the recess 60A to have a first recess 61A and a second recess 62A, the first magnet 11A is positioned inside the first recess 61A and the second magnet 12A is positioned inside the second recess 62A, which further shortens the distance between the first magnet 11A and the second magnet 12A and increases the magnetic coupling force between the first magnet 11A and the second magnet 12A. Therefore, the magnetic torque transmission unit 15 can efficiently transmit the torque of the first rotor 110 to the second rotor 120.

Figure 5 is a schematic diagram showing a first end plate 34A viewed in the axial direction according to one embodiment of the present disclosure. Figure 6 is a schematic diagram showing a cross section of the first end plate 34A as viewed in the direction of the arrows A-A in Figure 5. The first end plate 34A includes at least one through hole 353. In the illustrated embodiment, multiple through holes 353 are arranged along the circumferential direction.

With the above configuration, the second radial gap G2, which is the gap between the first rotor 110 and the pole piece rotor 30, and the space S1 in which the cooling fan 127 is disposed are connected by the through-holes 353. As a result, when the cooling fan 127 rotates, cooling air can flow between the first radial gap G1 and the space S1, promoting the flow of cooling air inside the housing 21. This improves the cooling performance of the magnetic-geared electric machine 10.

5 and 6 , at least a portion of the through hole 353 is arranged to be aligned with the recess 60A in the circumferential direction. As a more specific example, in the radial direction, the outer end of the through hole 353 and the outer end of the recess 60A are at approximately the same position, and the inner end of the through hole 353 and the inner end of the recess 60A are at approximately the same position. In this case, during operation of the magnetic-geared electric machine 10, the first magnet 11A and the second magnet 12A face each other across the through hole 353, for example, periodically (see FIG. 6 ).
In another embodiment, both ends of the through-hole 353 may be located radially inward of both ends of the recess 60A. In this case, the through-hole 353 is formed in the recess 60A.

With the above configuration, a magnetic field between the first magnet 11A and the second magnet 12A is formed inside the recess 60A, and the through-hole 353, at least a portion of which is circumferentially aligned with the recess 60A, does not impede the formation of this magnetic field. Therefore, the magnetic torque transmission unit 15 can efficiently transmit the torque of the first rotor 110 to the second rotor 120. Note that the above advantages can be obtained even in an embodiment in which a portion of the through-hole 353 is positioned at a different radial position from the recess 60A.

(Material of the opposing portion 37)
Returning to FIG. 4 , the first end plate 34A according to one embodiment of the present disclosure includes a facing portion 37 that faces the first magnet 11A and the second magnet 12A. The facing portion 37 illustrated in FIG. 4 is a recess 60 that includes a first recess 61 and a second recess 62. Although not shown in detail, the facing portion 37 according to an embodiment that does not include the recess 60 is a portion of the first end plate 34A that includes a surface facing the first magnet 11A and a surface facing the second magnet 12A, and has these two surfaces as both end surfaces. Both the surface facing the first magnet 11A and the surface facing the second magnet 12A may be flat.

The facing portion 37 according to an embodiment of the present disclosure may be made of a non-magnetic material. Examples of non-magnetic materials include carbon fiber reinforced plastics (CFRP) and stainless steel. According to the above configuration, the facing portion 37 is made of a non-magnetic material, which does not impede the formation of magnetism between the first magnet 11A (11) and the second magnet 12A (12). Therefore, the magnetic torque transmission unit 15 can efficiently transmit the torque of the first rotor 110 to the second rotor 120.
In another embodiment, the entire first end plate 34A, including the facing portion 37, may be made of a non-magnetic material. Even in this case, the above-described advantages can be obtained.

The facing portion 37 according to an embodiment of the present disclosure may be made of an insulator. One example of the insulator is CFRP. With the above configuration, even if the magnetic field between the first magnet 11A and the second magnet 12A passes through the facing portion 37, eddy currents in the first end plate 34A can be suppressed. Therefore, the magnetic torque transmission unit 15 can efficiently transmit the torque of the first rotor 110 to the second rotor 120.
In another embodiment, the entire first end plate 34A including the facing portion 37 may be made of an insulating material. Even in this case, the above-described advantages can be obtained.

(Structure for detecting rotational position of second rotor)
The magnetic-geared electric machine 10 illustrated in Fig. 3 includes a sensor 80 for measuring the rotational position of the second rotor 120. The sensor 80 may be a contact sensor that comes into contact with the second rotor 120, or a non-contact sensor that is located away from the second rotor 120. However, it is preferable that the sensor 80 be a non-contact sensor so that the rotation of the cooling fan 127 is not reduced. The non-contact sensor may be an optical sensor that includes a light-emitting element for emitting light onto the path of the cooling fan 127.

The rotational position of the first rotor 110 can be obtained based on the detection result of the sensor 80. For example, in an embodiment in which the second rotor 120 and the first rotor 110 rotate at the same speed, the rotational position of the second rotor 120 indicated by the sensor 80 can be considered to be the rotational position of the first rotor 110. The rotational position of the second rotor 120 is referenced when obtaining the torsion angle, which is the phase difference between the pole piece rotor 30 and the first rotor 110. If the torsion angle exceeds a specified range, predetermined control is executed to prevent the magnetic-geared electric machine 10 from losing synchronization.
For example, in an embodiment in which the magnetic-geared electric machine 10 is the magnetic-geared generator 10A, if the torsion angle exceeds a specified range, a torque reduction command is input to a power converter (not shown) that converts the power generated by the magnetic-geared generator 10A and supplies the power to the power supply destination 4, thereby reducing the torsion angle. The torque reduction command is a command to reduce the generator torque in the magnetic-geared generator 10A.
Furthermore, in an embodiment in which the magnetic-geared electric machine 10 is a magnetic-geared motor 10B, if the torsion angle exceeds a specified range, the control of energization of the stator coil 24 is changed to reduce the torsion angle.
With the above configuration, the rotational position of the first rotor 110 can be obtained based on the detection result of the sensor 80. Because there is no need to directly measure the rotational position of the first rotor 110, which is disposed across the cooling fan 127 and the first end plate 34A, the configuration of the magnetic-geared electric machine 10 can be simplified.
Furthermore, compared to a case where a sensor structure is employed that directly measures the rotational position of the first rotor 110, which is disposed across the cooling fan 127 and the first end plate 34A, the wiring of the sensor 80 can be shortened, simplifying the wiring arrangement structure. Furthermore, even when maintenance of the sensor 80 is performed, there is no need to remove at least one of the pole piece rotor 30 and the first end plate 34A connected to one end of the pole piece rotor 30, making maintenance easier.

The sensor 80 is arranged axially on the opposite side of the first end plate 34A, with at least a portion of the cooling fan 127 in between. In the example of Figure 3, the sensor 80 is arranged axially on the opposite side of the first end plate 34A, with the first cooling fan 121 of the cooling fan 127 in between, and is fixed to the housing 21. With the above configuration, the sensor 80 is arranged axially near the space So outside the magnetic-geared electric machine 10. This allows the wiring of the sensor 80 to be short, simplifying the arrangement structure of the sensor 80.

(Magnetic torque transmission unit according to another embodiment)
A magnetic torque transmission unit 16 according to another embodiment will be described with reference to FIG. 7 . The magnetic torque transmission unit 16 is an in-out type magnetic coupling. According to another embodiment, a first end plate 34B includes a regulating plate 341 whose thickness direction is in the radial direction. The magnetic torque transmission unit 16 is an in-out type magnetic coupling. As a more specific example, the magnetic torque transmission unit 16 includes a first magnet 11B (11) disposed radially inward from the regulating plate 341 and a second magnet 12B (12) disposed radially outward from the regulating plate 341, and the first magnet 11B and the second magnet 12B are magnetically coupled. The first magnet 11B is connected to the first rotor 110, and the second magnet 12B is connected to the second rotor 120. The regulating plate 341 includes a recess 60B (60) extending circumferentially and facing at least one of the first magnet 11B and the second magnet 12B. The recess 60B has an O-ring shape when viewed in the axial direction, and faces the first magnet 11B and the second magnet 12B in the radial direction. In the illustrated embodiment, the recess 60A has a first recess 61B (61) arranged so that the first magnet 11B is partially inserted therein, and a second recess 62B (62) arranged so that the second magnet 12B is partially inserted therein.

Even in the embodiment illustrated in FIG. 7, the magnetic torque transmission unit 16 can transmit the torque of the first rotor 110 to the second rotor 120, and can rotate the cooling fan 127 in conjunction with the first rotor 110 as a magnet rotor with a simple configuration. Furthermore, by providing the recess 60B, the distance between the first magnet 11B and the second magnet 12B is shortened, allowing the torque of the first rotor 110 to be efficiently transmitted to the second rotor 120.

(summary)
Below, an overview of some embodiments of the present disclosure is provided.

1) A magnetic-geared electric machine (10) according to at least one embodiment of the present disclosure includes:
a magnetic gear unit (5) including a stator (20); a pole piece rotor (30) disposed radially opposite the stator; a first rotor (110) including a plurality of magnets (42) positioned on the opposite side of the stator in the radial direction across the pole piece rotor; and end plates (first end plates 34A, 34B) disposed on one side of the first rotor in the axial direction and connected to one end of the pole piece rotor;
a second rotor (120) including a cooling fan (127) and disposed on the opposite side of the first rotor in the axial direction across the end plate;
The magnetic torque transmission unit (15, 16) includes a first magnet (11) provided on the first rotor and a second magnet (12) provided on the second rotor so as to be positioned on the opposite side of the end plate from the first magnet.

With the configuration of 1) above, the magnetic torque transmission unit can magnetically couple the first rotor, which serves as a magnet rotor, with the second rotor, which is disposed across the end plate from the first rotor. This allows the cooling fan to rotate in conjunction with the rotation of the first rotor, which serves as a magnet rotor. Because there is no need to mechanically couple the first rotor and the second rotor, the configuration of the magnetic-geared electric machine can be simplified. As a result, a magnetic-geared electric machine with a simple configuration is realized that rotates the cooling fan in conjunction with the magnet rotor.

2) In some embodiments, the magnetic-geared electric machine according to 1) above,
The end plate includes a recess (60) extending along a circumferential direction and facing at least one of the first magnet or the second magnet,
The at least one of the first magnet or the second magnet is positioned to at least partially penetrate the recess.

The configuration of 2) above allows the distance between the first magnet and the second magnet to be shortened, and the magnetic coupling force between the first magnet and the second magnet to be increased. As a result, the magnetic torque transmission unit can efficiently transmit the torque of the first rotor to the second rotor.

3) In some embodiments, the magnetic-geared electric machine according to 2) above,
The depression is
a first recess (61) facing the first magnet;
a second recess (62) facing the second magnet,
the first magnet is positioned to at least partially penetrate the first recess;
The second magnet is positioned to at least partially extend into the second recess.

The configuration of 3) above allows the distance between the first magnet and the second magnet to be further shortened, thereby increasing the magnetic coupling force between the first magnet and the second magnet. As a result, the magnetic torque transmission unit can efficiently transmit the torque of the first rotor to the second rotor.

4) In some embodiments, the magnetic-geared electric machine according to any one of 1) to 3) above,
The end plate includes a through hole (353).

With the configuration of 4) above, the gap between the first rotor and the pole piece rotor (second radial gap G2) and the space in which the cooling fan is located are connected by the through-holes, so that when the cooling fan rotates, cooling air can flow between the gap and the space. This improves the cooling performance of the magnetic-geared electric machine.

5) In some embodiments, the magnetic-geared electric machine according to any one of 1) to 4) above,
The end plate is
a recess (60) extending along a circumferential direction facing at least one of the first magnet or the second magnet;
and a through hole (353),
the at least one of the first magnet and the second magnet is positioned to at least partially penetrate into the recess;
At least a portion of the through hole is arranged to be aligned with the recess in the circumferential direction.

According to the configuration of 5) above, the gap (second radial gap G2) between the first rotor and the pole piece rotor is connected to the space in which the cooling fan is disposed by the through-hole. Therefore, when the cooling fan rotates, cooling air can flow between the gap and the space. This improves the cooling performance of the magnetic-geared electric machine. Furthermore, a magnetic field between the first magnet and the second magnet 12 is formed inside the recess, and the through-hole, at least a portion of which is circumferentially aligned with the recess, does not impede the formation of this magnetic field. Therefore, the magnetic torque transmission unit can efficiently transmit the torque of the first rotor to the second rotor.

6) In some embodiments, the magnetic-geared electric machine according to any one of 1) to 5) above,
The end plate includes an opposing portion (37) that faces the first magnet and the second magnet,
The facing portion is made of a non-magnetic material.

According to the configuration of 6) above, the opposing portion is made of a non-magnetic material, which does not impede the formation of magnetism between the first magnet and the second magnet. Therefore, the magnetic torque transmission unit can efficiently transmit the torque of the first rotor to the second rotor.

7) In some embodiments, the magnetic-geared electric machine according to any one of 1) to 6) above,
The end plate includes an opposing portion (37) that faces the first magnet and the second magnet,
The facing portion is an insulator.

The configuration of 7) above suppresses eddy currents in the end plates even when the magnetic field between the first and second magnets passes through the end plates. Therefore, the magnetic torque transmission unit can efficiently transmit the torque of the first rotor to the second rotor.

8) In some embodiments, the magnetic-geared electric machine according to any one of 1) to 7) above comprises:
A sensor (80) is provided for measuring the rotational position of the second rotor.

According to the configuration of 8) above, the rotational position of the first rotor can be obtained based on the detection results of the sensor. Since there is no need to directly measure the rotational position of the first rotor, which is disposed across the cooling fan and the end plate, the configuration of the magnetic-geared electric machine can be simplified.
In addition, compared to a case where a sensor structure is adopted that directly measures the rotational position of the first rotor disposed across the cooling fan and the end plate, the sensor wiring can be shortened and the wiring arrangement structure can be simplified. Furthermore, even when maintenance of the sensor is performed, there is no need to remove at least one of the pole piece rotor and the end plate connected to one end of the pole piece rotor, which makes maintenance easier.

9) In some embodiments, the magnetic-geared electric machine according to 8) above,
The sensor is disposed on the opposite side of the end plate in the axial direction, with at least a portion of the cooling fan sandwiched therebetween.

According to the configuration of 9) above, the sensor is positioned axially close to the outer space of the magnetic-geared electric machine. This allows the sensor wiring to be shortened, simplifying the sensor arrangement structure.

10) In some embodiments, the magnetic-geared electric machine according to any one of 1) to 9) above,
The magnetic torque transmission unit is a magnetic coupling.

The configuration of 10) above simplifies the configuration of the magnetic torque transmission unit compared to when the magnetic torque transmission unit is, for example, a magnetic gear.

11) In some embodiments, the magnetic-geared electric machine according to 10) above,
The first magnet and the second magnet face the end plate in the axial direction.

According to the configuration of 11) above, the end plate between the first magnet and the second magnet can be configured to extend radially, so that the axial arrangement space of the end plate can be made compact.
Furthermore, since the end plates can be configured to extend in the radial direction, the shape of the end plates can be simplified and the strength of the end plates can be ensured.

12) In some embodiments, the magnetic-geared electric machine according to any one of 1) to 11) above,
The pole piece rotor includes a plurality of pole pieces (32);
The number of pole pairs of the plurality of magnets of the first rotor is less than the number of magnetic poles of the plurality of magnetic pole pieces.

With the configuration of 12) above, the first rotor rotates at a higher speed than the pole piece rotor, increasing the airflow rate of the cooling fan linked to the first rotor. This improves the cooling performance of the magnetic-geared electric machine.

The above describes embodiments of the present disclosure, but the present disclosure is not limited to the above-described embodiments and also includes modifications to the above-described embodiments and appropriate combinations of these embodiments.

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.

5: Magnetic gear unit 10: Magnetic-geared electric machine 11: First magnet 12: Second magnet 15, 16: Magnetic torque transmission unit 20: Stator 30: Pole piece rotor 32: Pole pieces 34A, 34B: First end plate (end plate)
42: Magnet 60: Recess 61: First recess 62: Second recess 80: Sensor 110: First rotor 120: Second rotor 127: Cooling fan 353: Through hole

Claims (12)

a magnetic gear unit including a stator, a pole piece rotor disposed radially opposite the stator, a first rotor including a plurality of magnets positioned on the opposite side of the stator in the radial direction across the pole piece rotor, and an end plate disposed on one side of the first rotor in the axial direction and connected to one end of the pole piece rotor;
a second rotor including a cooling fan and disposed on the opposite side of the first rotor in the axial direction with the end plate interposed therebetween;
a magnetic torque transmission unit including a first magnet provided on the first rotor and a second magnet provided on the second rotor so as to be positioned on the opposite side of the end plate from the first magnet. the end plate includes a recess extending along a circumferential direction and facing at least one of the first magnet and the second magnet,
The magnetic-geared electric machine of claim 1 , wherein the at least one of the first magnet or the second magnet is positioned to at least partially extend into the recess. The depression is
a first recess facing the first magnet;
a second recess facing the second magnet,
the first magnet is positioned to at least partially penetrate the first recess;
The magnetic-geared electric machine of claim 2 , wherein the second magnet is positioned to at least partially extend into the second recess. The magnetic-geared electric machine according to claim 1 , wherein the end plates include through holes. The end plate is
a recess extending along a circumferential direction and facing at least one of the first magnet and the second magnet;
a through hole;
the at least one of the first magnet and the second magnet is positioned to at least partially penetrate into the recess;
The magnetic-geared electric machine according to claim 1 , wherein at least some of the through holes are arranged to align with the recesses in the circumferential direction. the end plate includes an opposing portion that faces the first magnet and the second magnet,
The magnetic-geared electric machine according to claim 1 , wherein the opposing portion is made of a non-magnetic material. the end plate includes an opposing portion that faces the first magnet and the second magnet,
The magnetic-geared electric machine according to claim 1 , wherein the opposing portion is an insulator. 8. A magnetic-geared electric machine according to claim 1, further comprising a sensor for measuring the rotational position of the second rotor. A magnetic-geared electric machine as described in claim 8, wherein the sensor is positioned on the opposite side of the end plate in the axial direction, across at least a portion of the cooling fan. 10. A magnetic-geared electric machine according to any one of claims 1 to 9, wherein the magnetic torque-transmitting unit is a magnetic coupling. The magnetic-geared electric machine according to claim 10 , wherein the first magnet and the second magnet face the end plate in the axial direction. the pole piece rotor includes a plurality of pole pieces;
The magnetic-geared electric machine according to claim 1 , wherein the number of pole pairs of the plurality of magnets of the first rotor is less than the number of magnetic poles of the plurality of magnetic pole pieces.