Magnetic geared rotating machine, power generation system, and pole piece rotor

Abstract

To provide a magnetic geared rotary machine, a power generation system and a magnetic pole piece rotor that can reduce eddy current loss while suppressing an influence on a magnetic path of a stator magnet.SOLUTION: A magnetic pole piece 32 of a magnetic geared rotary machine 10 includes an outer edge 60 and one or more inner edges 70. The outer edge 60 forms, in a radial section of the magnetic geared rotary machine 10, a first surface 51 of the magnetic pole piece 32 which faces a rotor 40 across a first air gap G1 and a second surface 52 of the magnetic pole piece 32 which faces a stator 20 across a second air gap G2. The inner edges 70 are located radially between the first surface 51 and second surface 52 to be encircled with the outer edge 60, and define one or more air gaps 80 in the magnetic pole piece 32. In the radial section, the first distance L1 radially between the first surface 51 and air gaps 80 is shorter than the second distance L2 radially between the second surface 52 and air gaps 80.SELECTED DRAWING: Figure 4A

Description

[Technical field]

[0001] The present disclosure relates to magnetic-geared rotating machines, power generation systems, and pole piece rotors. [Background technology]

[0002] Conventionally, magnetic-geared rotating machines that convert the rotational speed between two rotors to transmit torque are known. For example, a magnetic-geared rotating machine disclosed in Patent Document 1 includes, in order from the radially inner side, an internal rotor supporting multiple permanent magnets, an external rotor including multiple magnetic pole pieces, and a stator. The stator is provided with multiple windings and multiple stator magnets. When the internal rotor rotates due to a rotating magnetic field generated in response to a three-phase alternating current flowing through the windings, the magnetic flux generated by the permanent magnets of the internal rotor is modulated by the magnetic pole pieces. The external rotor rotates due to the modulated magnetic field and the magnetic field of the stator magnets. [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-geared rotating machine is in operation, eddy currents flow in the pole pieces when magnetic flux flows in the axial direction and passes through the pole pieces, resulting in eddy current loss. Measures are required to reduce eddy current loss, but it is preferable that these measures have as little effect as possible on the magnetic paths in the multiple stator magnets.

[0005] The present disclosure aims to provide a magnetic-geared rotating machine, a power generation system, and a pole piece rotor that can reduce eddy current loss while suppressing the effect on the magnetic path of a stator magnet. [Means for solving the problem]

[0006] A magnetic-geared rotating machine according to at least one embodiment of the present invention comprises: A stator including a plurality of stator magnets arranged in a circumferential direction; a rotor including a plurality of rotor magnets arranged in the circumferential direction, the rotor magnets having a number of magnetic poles smaller than the number of the stator magnets; a pole piece rotor including a plurality of pole pieces arranged in the circumferential direction at a radial position between the stator and the rotor; A magnetic-geared rotating machine comprising: Each of the pole pieces has, in a radial cross section of the magnetic-geared rotating machine: an outer edge defining a first face of the pole piece facing the rotor across a first air gap and a second face of the pole piece facing the stator across a second air gap; one or more inner edges positioned radially between the first surface and the second surface and surrounded by the outer edge, the inner edges defining one or more gaps within the pole piece; Including, In the radial cross section, a first distance that is the shortest distance in the radial direction between the first surface and the gap is shorter than a second distance that is the shortest distance in the radial direction between the second surface and the gap.

[0007] A power generation system according to at least one embodiment of the present invention includes: The prime mover, the magnetic-geared rotating machine as a magnetic gear generator driven by an input from the prime mover to generate electricity; Equipped with.

[0008] A pole piece rotor according to at least one embodiment of the present invention comprises: A plurality of magnetic pole pieces arranged in a circumferential direction; A plurality of holders arranged alternately with a plurality of the magnetic pole pieces in the circumferential direction; Equipped with The pole pieces, in radial cross section, An outer edge forming a first surface facing one side in a radial direction and a second surface facing the other side in the radial direction; one or more inner edges located radially between the first surface and the second surface and surrounded by the outer edge, the inner edges defining one or more gaps within the pole piece; Including, In the radial cross section, a first distance that is the shortest distance in the radial direction between the first surface and the gap is shorter than a second distance that is the shortest distance in the radial direction between the second surface and the gap. Effect of the Invention

[0009] According to the present disclosure, it is possible to provide a magnetic-geared rotating machine, a power generation system, and a pole piece rotor that can reduce eddy current loss while suppressing the effect on the magnetic path of the stator magnet. [Brief description of the drawings]

[0010] [Figure 1A] FIG. 1 is a schematic diagram illustrating a magnetic-geared rotating machine according to an embodiment. [Figure 1B] FIG. 13 is a schematic diagram illustrating a magnetic-geared rotating machine according to another embodiment. [Diagram 2] FIG. 1 is a radial cross-sectional view of a magnetic-geared rotating machine according to an embodiment. [Diagram 3] FIG. 2 is a perspective view of a pole piece rotor according to one embodiment. [Figure 4A] FIG. 2 is a cross-sectional view of a pole piece according to one embodiment. [Figure 4B] FIG. 11 is a cross-sectional view of a pole piece according to another embodiment. [Figure 4C] FIG. 11 is a cross-sectional view of a pole piece according to another embodiment. [Figure 4D] FIG. 11 is a cross-sectional view of a pole piece according to another embodiment. [Figure 4E] FIG. 11 is a cross-sectional view showing a partition member according to another embodiment. [Figure 4F] FIG. 11 is a cross-sectional view showing a partition member according to another embodiment. [Figure 4G] FIG. 11 is a cross-sectional view showing a partition member according to another embodiment. [Diagram 5] 10A and 10B are diagrams showing an effect of reducing eddy current loss according to an embodiment; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of components described as the embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the present invention.

[0012] (Overview of magnetic-geared rotating machines) 1A and 1B are schematic diagrams illustrating an example of a magnetic-geared rotating machine, where in Fig. 1A and 1B, "axial" refers to a direction parallel to the rotational axis of pole pieces rotor 30 and rotor 40 of magnetic-geared rotating machine 10, and "radial" refers to a direction perpendicular to the rotational axis of pole pieces 32 and rotor 40. 1A, in one embodiment, the magnetic-geared rotating machine 10 is a magnetic-geared generator 10A for generating electricity when driven by an input from a prime mover 2. The magnetic-geared generator 10A is configured to supply electric power P generated by the power generation 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 rotating machine 10 is a magnetic-geared motor 10B configured to receive power P from a power supply 6, which may be, for example, an electric power grid, to drive the rotating machine 8.

[0013] In the embodiment shown in Fig. 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 prime mover 2 is a wind turbine rotor. When the power generation system 1 is a tidal power generation system, the prime mover 2 is a water turbine rotor. The magnetic-geared generator 10A includes a stator 20 including a stator magnet 22 and a stator winding 24, a pole piece rotor 30 including a pole piece 32, and a rotor 40 including a rotor magnet 42. In the example shown in FIG. 1A, the stator 20 is disposed inside a housing 21 that supports a rotating shaft 3 of a prime mover 2 via a bearing B1. The pole piece rotor 30 is configured to rotate together with the rotating shaft 3 of the prime mover 2. The pole piece 32 of the pole piece rotor 30 includes a plurality of electromagnetic steel plates 35 that are stacked in the axial direction. The pole piece rotor 30 includes end rings 34 provided at both axial ends of the pole piece 32, and each end ring 34 is connected to the rotating shaft 3. The rotor 40 includes end plates 44 provided at both axial ends of the rotor magnets 42. Each end plate 44 is attached to the rotating shaft 3 (or the pole piece rotor 30 which rotates together with the rotating shaft 3) via a bearing B2 so as to allow the rotor 40 to rotate faster than the rotating shaft 3 and the pole piece rotor 30. The rotor 40 is disposed within a region surrounded by the pole piece rotor 30, including the pole pieces 32 and end rings 34, and the rotating shaft 3. 1A, the magnetic-geared generator 10A has a configuration in which the stator 20, the pole piece rotor 30, and the rotor 40 are arranged in this order toward the inside in the radial direction. In another embodiment, the magnetic-geared generator 10A has a configuration in which the rotor 40, the pole piece rotor 30, and the stator 20 are arranged in this order toward the inside in the radial direction. In this case, the rotor 40, the pole piece rotor 30, and the stator 20 are arranged on the radially inside of the cylindrical rotating shaft 3.

[0014] The magnetic-geared generator 10A described above is an integrated combination of a magnetic gear and a generator, and converts the mechanical input from the prime mover 2 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 magnets 22 is modulated by the pole pieces 32 of the pole piece rotor (low-speed rotor) 30 that rotates together with the rotating shaft 3 of the prime mover 2, and the rotor magnets 42 receive a magnetic force from the modulated magnetic field, causing the rotor (high-speed rotor) 40 to rotate. At this time, the ratio of the rotation speed of the rotor 40 to that of the pole piece rotor 30 (speed-up ratio) is determined by the number of pole pairs N of the rotor magnets 42. H Number of poles N of pole piece 32 for L Ratio (=N L / N H When the rotor 40 rotates, a current is generated in the stator winding 24 by electromagnetic induction. L is the number of pole pairs N of the stator magnet 22 S More than. When the magnetic-geared generator 10A is in operation, N H Next flux (main flux) and N H Harmonic flux higher than the next order (e.g., N H +N S Various magnetic fluxes may occur, such as leakage flux Lf (magnetic fluxes following the axial direction). Part of these magnetic fluxes becomes leakage flux Lf that passes through the pole pieces 32 in the axial direction, for example to avoid the stator magnets 22. When leakage flux Lf occurs, eddy currents may be generated in the in-plane direction in each of the electromagnetic steel sheets 35. Relatively large eddy currents may be generated in the electromagnetic steel sheets 35 at, for example, both axial ends of the pole pieces 32.

[0015] In the embodiment shown in FIG. 1B, the basic configuration of a magnetic-geared motor 10B is common to that of the magnetic-geared generator 10A shown in FIG. 1A. That is, the magnetic-geared motor 10B includes a stator 20 including a stator magnet 22 and a stator winding 24, a pole piece rotor 30 including a pole piece 32, and a rotor 40 including a rotor magnet 42. In the example shown in FIG. 1B, the stator 20 is fixed inside a housing 21 that supports a rotating shaft 9 of a rotating machine 8 via a bearing B1. The pole piece 32 of the pole piece rotor 30 includes a plurality of electromagnetic steel plates 35 that are stacked in the axial direction. The pole piece rotor 30 includes end rings 34 provided at both axial ends of the pole piece 32, and each end ring 34 is connected to the rotating shaft 9. The rotor 40 includes end plates 44 provided at both axial ends of the rotor magnet 42. Each end plate 44 is attached to the rotating shaft 9 (or the pole piece rotor 30 that rotates together with the rotating shaft 9) via a bearing B2 so as to allow the rotor 40 to rotate faster than the rotating shaft 9 and the pole piece rotor 30. The rotor 40 is disposed within the area surrounded by the pole piece rotor 30 including the pole pieces 32 and the end rings 34 and the rotating shaft 9 . 1B, the magnetic-geared motor 10B has a configuration in which the stator 20, the pole piece rotor 30, and the rotor 40 are arranged in this order toward the inside in the radial direction. In another embodiment, the magnetic-geared motor 10B has a configuration in which the rotor 40, the pole piece rotor 30, and the stator 20 are arranged in this order toward the inside in the radial direction. In this case, the rotor 40, the pole piece rotor 30, and the stator 20 are arranged on the radial inside of the cylindrical rotating shaft 9.

[0016] The magnetic-geared motor 10B is an integrated combination of a magnetic gear and a motor, and rotates a rotor (high-speed rotor) 40 by a rotating magnetic field generated by energizing the stator windings 24. Power is transmitted from the rotor 40 to the pole piece rotor (low-speed rotor) 30 using the principle of harmonic magnetic gears. When the magnetic-geared motor 10B is in operation, similar to the magnetic-geared generator 10A, leakage magnetic flux Lf in the axial direction may be generated in the pole pieces 32. In this case, eddy currents may be generated in the in-plane direction in each pole piece 32. Relatively large eddy currents may be generated in the magnetic steel sheets 35 at both axial ends of the pole pieces 32, for example.

[0017] (Internal structure of a magnetic-geared electric machine) Next, the internal structure of the above-described magnetic-geared rotating machine 10 (10A, 10B) will be described with reference to FIG. FIG. 2 is a radial cross-sectional view of a magnetic-geared rotating machine 10 according to an embodiment. In FIG. 2, only some of the components of the magnetic-geared rotating machine 10 are hatched for ease of viewing. In FIG. 2, the "circumferential direction" is the circumferential direction based on the already-mentioned "axial direction" (see FIG. 1A and FIG. 1B). 2, the stator 20 of the magnetic-geared rotating machine 10 includes a plurality of stator magnets 22 arranged side by side in the circumferential direction and a stator winding 24. The stator magnets 22 and the stator winding 24 are attached to a stator core 23.

[0018] The stator magnets 22 are made of permanent magnets, and are provided in multiple numbers in the circumferential direction so as to pass between the stator winding 24 and the pole piece rotor 30 in the radial direction in the axial direction. In this example, the multiple stator magnets 22 are made of multiple stator magnets 22N, 22S with different magnetic poles that are alternately arranged in the circumferential direction. In the example shown in Fig. 2, each stator magnet 22 is a rod-shaped member that is long in the axial direction and has a rectangular cross section. 2 shows the stator 20 having a surface permanent magnet (SPM) structure in which the stator magnets 22 are 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 magnets 22 are embedded in the stator core 23.

[0019] The stator winding 24 is provided in a plurality of slots 25 provided in the stator core 23. The plurality of slots 25 are provided in the circumferential direction, and each of the slots 25 extends in the axial direction. Both axial ends of each slot 25 are open, and coil ends of the stator winding 24 that do not fit in the slots 25 may protrude from the stator core 23 at both axial ends of the stator core 23.

[0020] The rotor 40, which is disposed at a position radially offset from the stator 20 of the above configuration, includes a plurality of rotor magnets 42 arranged in a line in the circumferential direction. The rotor magnets 42 are a plurality of permanent magnets with different magnetic poles arranged alternately in the circumferential direction. The number of magnetic poles of the rotor magnets 42 is less than the number of magnetic poles of the stator magnets 22. Each rotor magnet 42 may be a long rod member having a rectangular cross section.

[0021] 2 shows rotor 40 having a surface permanent magnet (SPM) structure in which rotor magnets 42 are attached to the surface of rotor core 43. In other embodiments, rotor 40 may have an interior permanent magnet (IPM) structure in which rotor magnets 42 are embedded in rotor core 43.

[0022] 1A and 1B, the rotor 40 may include the end plates 44 described above with reference to Fig. 1A and 1B in addition to the rotor magnets 42 and the rotor core 43. The end plates 44 are annular plates extending radially from the mounting position of the bearing B2 toward the rotor core 43.

[0023] The pole piece rotor 30 includes a plurality of pole pieces 32 arranged in a circumferential line at a radial position between the stator 20 and the rotor 40 configured as described above. Each pole piece 32 faces the rotor 40 across a first air gap G1 and faces the stator 20 across a second air gap G2. For example, in an embodiment in which the rotor 40 and the stator 20 both have an embedded magnet structure, the pole piece rotor 30 faces the rotor magnet 42 across the first air gap G1 and faces the stator magnet 22 across the second air gap G2. In another embodiment, the pole piece rotor 30 may face each of the stator core 23 and the rotor core 43. The pole piece rotor 30 further includes a plurality of holders 39 arranged alternately with the plurality of pole pieces 32 in the circumferential direction. In one embodiment, each holder 39 is made of a non-magnetic material. In another embodiment, the holder 39 may be made of a magnetic material. Each pole piece 32 is sandwiched and held by two holders 39 on both sides in the circumferential direction. Each pole piece 32 includes a plurality of the aforementioned electromagnetic steel sheets 35 (see FIGS. 1A and 1B) stacked in the axial direction.

[0024] Next, further details of the configuration of the pole piece rotor 30 will be described with reference to FIG. FIG. 3 is a perspective view of a pole piece rotor 30 according to one embodiment. 3, the pole piece rotor 30 includes a pair of end rings 34 located on either side in the axial direction, sandwiching a plurality of pole pieces 32 and a plurality of holders 39. One of the pair of end rings 34 is illustrated by a two-dot chain line. In the embodiment illustrated in FIG. 3, the pole piece rotor 30 includes a plurality of tie bars 36 extending axially between a pair of end rings 34. Each tie bar 36 is disposed in an axial hole 86 formed in each pole piece 32 and is held by a pair of end rings 34. By disposing a plurality of tie bars 36, the pole piece rotor 30 can form an assembly of a plurality of pole pieces 32. In addition, by disposing a plurality of tie bars 36, it is possible to suppress the pole pieces 32 from shifting radially outward when the pole piece rotor 30 rotates. Each tie bar 36 is formed of a non-magnetic material, such as titanium or stainless steel. In other embodiments, the pole piece rotor 30 may not include multiple tie bars 36. In this case, the pole pieces 32 may not have axial holes 86 formed therein. Even in such embodiments, the pole piece rotor 30 may form an assembly of multiple pole pieces 32.

[0025] Further construction details of pole piece 32 are described with reference to Figures 4A-4G. 4A to 4G are cross-sectional views showing magnetic pole pieces 32A to 32G (32) according to an embodiment. As an example, Fig. 4A to 4G show an embodiment in which rotor 40 and stator 20 both have a surface magnet type structure. In order to make the drawings easier to understand, the components shown in the drawings are not hatched, and holder 39 (see Fig. 3) is not shown. 4A and 4B show an embodiment in which a plurality of tie bars 36 (see FIG. 3) is not provided, and FIGS. 4C to 4G show an embodiment in which a plurality of tie bars 36 (see FIG. 3) is provided.

[0026] 4A to 4G, the pole pieces 32A to 32G (32) include an outer edge 60 and one or more inner edges 70A to 70G (70) in radial cross section. The outer edge 60 forms a first surface 51 of the pole piece 32 that faces the rotor 40 across a first air gap G1, and a second surface 52 of the pole piece 32 that faces the stator 20 across a second air gap G2. The first surface 51 faces one radial side, and the second surface 52 faces the other radial side. The inner edge 70 is located between the first surface 51 and the second surface 52 in the radial direction so as to be surrounded by the outer edge 60, and defines one or more gaps 80A-80G (80) inside the pole piece 32. Eddy currents that may be generated in each pole piece 32 due to leakage flux Lf (see FIGS. 1A and 1B) tend to flow along the edge of the pole piece 32. In this regard, by providing one or more inner edges 70 that define one or more gaps 80, the eddy current path 7 includes paths 5A-5G (5) along the inner edges 70, so that the pole piece 32 can lengthen the eddy current paths 7A-7G (7). In addition, in the radial cross section, a first distance L1, which is the shortest distance in the radial direction between the first surface 51 and the gaps 80A-80G (80), is smaller than a second distance L2, which is the shortest distance in the radial direction between the second surface and the gaps 80. Therefore, the inner edge 70 is disposed on the rotor 40 side in the pole piece 32, and the gaps 80 can be moved radially away from the stator magnet 22. Therefore, the magnetic path of the magnetic flux flowing in the circumferential direction generated from the multiple stator magnets 22 is prevented from being blocked by the gaps 80. Note that the magnetic flux generated from the stator magnet 22 applies torque to the pole piece 32. In some embodiments where the magnetic-geared rotating machine 10 is a magnetic-geared generator 10A, the torque applied to the pole pieces 32 is a torque for braking the pole piece rotor 30 which rotates with the rotating shaft 3. On the other hand, in some embodiments where the magnetic-geared rotating machine 10 is a magnetic-geared motor 10B, the torque applied to the pole pieces 32 is a torque for assisting the rotation of the pole piece rotor 30.

[0027] 4A and 4G, the gaps 80A, 80G (80) of the pole pieces 32A, 32G (32) may be arranged such that the first distance L1 is greater than 0. In this case, the inner edges 70A, 70G (70) do not connect to the outer edges 60. The eddy current paths 7A, 7G (7) may include intermediate paths 11A, 11G between the gaps 80A, 80G and the first surface 51 in addition to the paths 5A, 5G (5) along the inner edges 70A, 70G. 4B to 4F, the gaps 80B to 80F (80) may be arranged such that the first distance L1 is 0. In this case, at least one of the inner edges 70B to 70F (70) is connected to the outer edge 60, and therefore the proportion of the eddy current induced in the paths 5B to 5F (5) along the inner edge 70 increases. 4B to 4G, the gaps 80A to 80G (80) may be disposed such that the first distance L1 is shorter than the shortest radial distance L3 from the rotor 40 to the outer edge 60. In this case, the inner edge 70 is close to the outer edge 60 on the rotor 40 side, so that the proportion of eddy currents induced in the paths 5B to 5G along the inner edge 70 increases. Note that, as shown in FIG. 4A, the first distance L1 may be longer than the shortest radial distance L3 from the rotor 40 to the outer edge 60.

[0028] As shown in Figures 4A to 4F, the pole pieces 32A to 32F (32) may include one or more slits 85A to 85F (85) that form at least a part of the gaps 80A to 80F (80) defined by the inner edges 70A to 70F (70). It is preferable that the magnetic path of the magnetic flux flowing in the radial direction generated from the rotor magnet 42 is not interrupted as much as possible. In this regard, by forming at least a part of the gaps 80A to 80F with the slits 85A to 85F, the magnetic path of the magnetic flux generated from the rotor magnet 42 is prevented from being interrupted by the gap 80 in the width direction of the slits 85.

[0029] 4B and 4D, each of slits 85B, 85D (85) may include one or more open slits 82 that open to first surface 51. In this case, at least a portion of inner edges 70B, 70D (70) is connected to outer edge 60, so that the proportion of eddy currents induced in paths 5B, 5D (5) along inner edge 70 is further increased. As shown in FIG. 4D and FIG. 4F, a plurality of inner edges 70D, 70F (70) may be provided. For example, the three inner edges 70D shown in FIG. 4D are connected to each other via the first surface 51. Among the three inner edges 70F shown in FIG. 4F, the inner edge 70F on the central side is connected to the remaining two inner edges 70F via the first surface 51 and the end surface 53 in the circumferential direction of the pole piece 32F. In FIG. 4D and FIG. 4F, the number of gaps 80D, 80F (80) is three. The number of inner edges 70 and gaps 80 may be, for example, two or four or more.

[0030] As shown in Figures 4C to 4G, the pole pieces 32C to 32G (32) may have axial holes 86C to 86G (86) formed as part of the gaps 80C to 80G (80). In this case, each of the connecting bars 36 (see Figure 3) described above may be disposed in the axial holes 86C to 86G formed as part of the gaps 80C to 80G. 4C to 4F, the above-mentioned slits 85A to 85F may include one or more communicating slits 84 that communicate with the axial holes 86C to 86F (86). By having the communicating slits 84 communicate with the axial hole 86, even if the axial hole 86 is formed in the central region of the pole piece 32, the eddy current path 7 can be effectively extended. 4D, the one or more opening slits 82 may open to the first surface 51 at a position shifted in the circumferential direction from the communicating slit 84. That is, the slit 85D (85) may include the communicating slit 84 and one or more opening slits 82 that open to the first surface 51 at a position shifted in the circumferential direction from the communicating slit 84. In this case, the pole piece 32D has an inner edge 70 that defines the axial hole 86D and the communicating slit 84, and another inner edge 70 that is connected to the inner edge 70 via the first surface 51. This effectively extends the path 5D of the eddy current along the inner edge 70. In the pole piece 32D shown in Fig. 4D, the number of communication slits 84 may be one, and the number of opening slits 82 may be two or more. As a more specific example, the slit 85D (85) may include two opening slits 82 arranged symmetrically with respect to one communication slit 84. In this case, an eddy current path 5D is formed along the inner edge 70D on each of one and the other circumferential sides of the communication slit 84. Since the portion of the pole piece 32D where the eddy current is generated is prevented from being biased in the circumferential direction, it is possible to prevent the temperature of only a specific portion of the pole piece 32D from excessively increasing. 4E, a plurality of communication slits 84 communicating with the axial hole 86E (86) may be provided. For example, the communication slits 84 may include a first communication slit 84A that opens into the first surface 51, and one or more second communication slits 84B that are disposed at positions shifted in the circumferential direction from the first communication slit 84A and at positions shifted in the radial direction from the first surface 51. In this case, the path 5E of the eddy current along one inner edge 70E that defines the axial hole 86E, the first communication slit 84A, and the second communication slit 84B can be effectively extended. In the pole piece 32E shown in FIG. 4E, the number of the first communication slits 84A may be one, and the number of the second communication slits 84B may be two or more. As a more specific example, the slit 85E (85) may include two second communication slits 84B arranged at positions symmetrical to each other with one first communication slit 84A in between. In this case, an eddy current path 5E is formed along the inner edge 70E on each of one side and the other side in the circumferential direction of the first communication slit 84A. Since the portion of the pole piece 32E where the eddy current is generated is prevented from being biased in the circumferential direction, it is possible to prevent the temperature of only a specific portion of the pole piece 32E from excessively increasing. As shown in FIG. 4F, the slit 85F (85) may include one or more end face opening slits 83. The end face opening slits 83 are arranged at a position shifted in the circumferential direction with respect to the axial hole 86F (86) and open to the end face 53 of the pole piece 32F (32) in the circumferential direction. In this case, an inner edge 70 that defines the axial hole 86F and the communication slit 84, and another inner edge 70 that is connected to the inner edge 70 via the first surface 51 and the end face 53 are arranged. This makes it possible to effectively extend the path 5F of the eddy current along the inner edge 70. The end face 53 may be one end face in the circumferential direction of the pole piece 32F, or both end faces in the circumferential direction of the pole piece 32F. In addition, in the pole piece 32F shown in Fig. 4F, the number of communication slits 84 may be one, and the number of end face opening slits 83 may be two or more. As a more specific example, the slit 85F (85) may include two end face opening slits 83 arranged at positions symmetrical to each other with one communication slit 84 in between. In this case, a path 5F is formed along the inner edge 70F on each of one side and the other side in the circumferential direction with respect to the communication slit 84. Since the portion of the pole piece 32F where eddy currents are generated is prevented from being biased in the circumferential direction, it is possible to prevent the temperature of only a specific portion of the pole piece 32D from excessively increasing. Furthermore, the inner edges 70C, 70D (70) may define the gaps 80C, 80D (80) over the entire axial range of the magnetic-geared rotating machine 10 (see FIG. 5 ). As a more specific example, all of the magnetic steel sheets 35 included in the pole pieces 32C, 32D may include the inner edges 70C, 70D that define the gaps 80C, 80D. In another embodiment, the inner edges 70C, 70D may define the air gaps 80C, 80D in a portion of the axial direction of the magnetic-geared rotating machine 10. As a more specific example, some of the magnetic steel sheets 35 included in the pole pieces 32C, 32D may include the inner edges 70C, 70D that define the air gaps 80C, 80D.

[0031] As shown in FIGS. 4A to 4F, the inner edges 70A to 70F (70) may include a pair of linear portions 87A to 87F (87) facing each other with a gap 80A to 80F (80) therebetween in a radial cross section. The width (dimension W) of the gaps 80A-80F between a pair of straight portions 87 may be four times or less the thickness of each of the electromagnetic steel sheets 35 (see FIG. 1). This allows the width of the gaps 80A-80F to be narrowed, thereby preventing the magnetic path of the magnetic flux generated from the rotor magnet 42 from being blocked by the gaps 80A-80F. Furthermore, the width (dimension W) of the gaps 80A-80F between a pair of straight portions 87 may be more than twice the thickness of each of the electromagnetic steel sheets 35 (see FIG. 1). Because the width (dimension W) of the gaps 80A-80F is sufficiently larger than the thickness of the electromagnetic steel sheets 35, the electromagnetic steel sheets 35 can be stably processed.

[0032] FIG. 5 is a diagram showing the effect of reducing eddy current loss according to one embodiment. FIG. 5 shows the results of eddy current loss obtained by simulation when magnetic-geared motor 10B is driven under specified conditions using comparative example 37 and pole pieces 32C and 32D. The material, outer dimensions, and number of laminated sheets of the electromagnetic steel sheets 35 employed in Comparative Example 37 are the same as those of the pole pieces 32C and 32D. The pole piece shown in Comparative Example 37 has an axial hole 86 formed in the center. 5, it can be seen that the eddy current loss decreases as the number of slits 85 increases. This is thought to be because the more slits 85 there are, the longer the path 5 along the inner edge 70 becomes, which increases the resistance of the eddy current in the pole piece 32 and reduces the eddy current. The principle by which leakage magnetic flux Lf occurs is the same in magnetic-geared motor 10B and magnetic-geared generator 10A. Therefore, in a simulation of eddy currents when magnetic-geared rotating machine 10 is operated instead of magnetic-geared motor 10B, the same results as in Fig. 5 are obtained. That is, in magnetic-geared generator 10A as well, eddy current loss is lowest when pole piece 32D is used among comparative example 37 and pole pieces 32C and 32D.

[0033] (summary) Hereinafter, an overview will be given of a magnetic-geared rotating machine 10 according to several embodiments and a power generation system 1 using the same.

[0034] (1) A magnetic-geared rotating machine (10) according to at least one embodiment of the present invention includes: A stator (20) including a plurality of stator magnets (22) arranged in a circumferential direction; a rotor (40) including a plurality of rotor magnets (42) arranged in line in the circumferential direction and having a smaller number of magnetic poles than the plurality of stator magnets (22); a pole piece rotor (30) including a plurality of pole pieces (32) arranged in a radial position between the stator (20) and the rotor (40) so as to be aligned in the circumferential direction; A magnetic-geared rotating machine (10) comprising: Each of the pole pieces (32) has, in a radial cross section of the magnetic-geared rotating machine (10): an outer edge (60) forming a first surface (51) of the pole piece (32) facing the rotor (40) across a first air gap (G1) and a second surface (52) of the pole piece (32) facing the stator (20) across a second air gap (G2); one or more inner edges (70) positioned radially between the first surface (51) and the second surface (52) so as to be surrounded by the outer edge (60) and defining one or more gaps (80) within the pole piece (32); Including, In the radial cross section, a first distance (L1), which is the shortest distance in the radial direction between the first surface (51) and the gap (80), is shorter than a second distance (L2), which is the shortest distance in the radial direction between the second surface (52) and the gap (80).

[0035] According to the above configuration (1), the eddy current path (7), which is a path of eddy currents generated in the pole pieces (32) as the magnetic-geared rotating machine (10) operates, includes a path (5) along one or more inner edges (70). Therefore, the magnetic-geared rotating machine (10) can lengthen the eddy current path (7). Therefore, the eddy current resistance in the pole pieces (32) increases, and the eddy currents are reduced. In addition, since the first distance (L1) is shorter than the second distance (L2), the one or more inner edges (70) are disposed on the rotor (40) side, and the one or more air gaps (80) can be moved radially away from the stator (20). Therefore, the magnetic path of the magnetic flux flowing in the circumferential direction generated by the multiple stator magnets (22) is prevented from being blocked by the one or more air gaps (80). This prevents the rotation of the pole piece rotor (30) from being hindered. As a result, a magnetic-geared rotating machine (10) is achieved that can reduce eddy current loss while preventing interruption of the magnetic path of the stator magnet (22).

[0036] (2) In some embodiments, in the configuration of (1) above, Each of the pole pieces (32) includes a plurality of magnetic steel sheets (35) stacked in the axial direction of the magnetic-geared rotating machine (10); The inner edge (70) includes a pair of straight line portions (87) opposed to each other across the gap (80) in the radial cross section, The width (dimension W) of the gap (80) between the pair of straight portions (87) is four times or less the thickness of each of the electromagnetic steel plates (35).

[0037] According to the above configuration (2), the magnetic-geared rotating machine (10) can reduce the width (dimension W) of the gap (80), thereby preventing the magnetic path of the radially flowing magnetic flux generated by the rotor magnet (42) from being blocked by the gap (80).

[0038] (3) In some embodiments, in the configuration of (1) or (2), Each of the pole pieces (32) includes a plurality of magnetic steel sheets (35) stacked in the axial direction of the magnetic-geared rotating machine (10); The inner edge (70) includes a pair of straight line portions (87) opposed to each other across the gap (80) in the radial cross section, The width (dimension W) of the gap (80) between the pair of straight portions (87) is at least twice the thickness of each of the electromagnetic steel plates (35).

[0039] According to the above configuration (3), the width of the gap (80) is sufficiently larger than the thickness of the electromagnetic steel sheet (35), so that the electromagnetic steel sheet (35) can be stably processed. For example, in an embodiment in which the electromagnetic steel sheet (35) is produced by press working, the width (dimension W) of the gap (80) is large, so that a larger punch can be used during processing. This improves the durability of the punch, so that the electromagnetic steel sheet (35) can be stably press worked.

[0040] (4) In some embodiments, in any one of the configurations (1) to (3) above, The first distance (L1) is less than the shortest radial distance (L3) from the rotor (40) to the outer edge (60).

[0041] According to the above configuration (3), the inner edge (70) is close to the outer edge (60) on the rotor (40) side, so that the proportion of eddy current induced in the path (5) along the inner edge (70) increases. Therefore, the magnetic-geared rotating machine (10) can further reduce eddy currents.

[0042] (5) In some embodiments, in any one of the configurations (1) to (4) above, Each of the pole pieces (32) includes one or more slits (85) that define at least a portion of the gap (80) defined by the inner edge (70).

[0043] According to the above configuration (5), the pole piece (32) includes the slit (85) forming at least a part of the gap (80), so that the magnetic path of the radially flowing magnetic flux generated from the rotor magnet (42) can be prevented from being blocked by the gap (80) in the width direction of the slit (85).

[0044] (6) In some embodiments, in the configuration of (5) above, The slit (85) includes one or more opening slits (82) that open to the first surface (51).

[0045] According to the above configuration (6), since the inner edge (70) is connected to the outer edge (60), the proportion of eddy current induced in the path (5) along the inner edge (70) is further increased, and therefore the magnetic-geared rotating machine (10) can further reduce eddy currents.

[0046] (7) In some embodiments, in any one of the configurations (1) to (6) above, The pole piece rotor (30) is a pair of end rings (34) positioned on either side of the plurality of magnetic pole pieces (32) in the axial direction; a plurality of connecting bars (36) extending in the axial direction between the pair of end rings (34); Equipped with Each of the tie bars (36) is disposed within an axial bore (86) formed in each of the pole pieces (32) as part of the air gap (80).

[0047] According to the above-mentioned configuration (7), the pole piece rotor (30) can form an assembly of a plurality of pole pieces (32). Also, the inner wall of the axial hole (86) of the pole piece (32) for mounting the connecting bar (36) can be used as the inner edge (70) for lengthening the eddy current path (7). This allows the magnetic-geared rotating machine (10) to further reduce the path of eddy currents.

[0048] (8) In some embodiments, in the configuration of (7) above, each of the pole pieces (32) includes one or more slits (85) that define at least a portion of the gap (80) defined by the inner edge (70); The slit (85) includes one or more communicating slits (84) that communicate with the axial hole (86).

[0049] According to the above configuration (8), the axial hole (86) tends to be formed in the central region of the pole piece (32) in order to reliably support the pole piece (32) by the connecting bar (36), so little effect of extending the eddy current path (7) can be expected. Therefore, by arranging the communication slit (84) that communicates with the axial hole (86), the eddy current path (7) can be effectively extended.

[0050] (9) In some embodiments, in the configuration of (8), The communication slit (84) opens into the first surface, The slits (85) include one or more opening slits (82) that open into the first surface at a position shifted from the communication slit (84) in the circumferential direction.

[0051] According to the above configuration (9), at least a portion of the inner edge (70) is connected to the outer edge (60), so the proportion of eddy currents induced in the path (5) along the inner edge (70) is further increased.

[0052] (10) In some embodiments, in the configuration of (9), The slit (85) includes two of the opening slits (82) arranged symmetrically with respect to one of the communication slits (84).

[0053] According to the above configuration (10), an inner edge (70) is disposed that defines the axial hole (86) and the communication slit (84), and another inner edge (70) is disposed that is connected to the inner edge (70) via the first surface (51). This makes it possible to effectively extend the path (5) of the eddy current along the inner edge (70).

[0054] (11) In some embodiments, in the configuration of (8), The communication slit (85) is a first communication slit (85A) opening to the first surface (51); one or more second communication slits (85B) disposed at positions shifted in the circumferential direction with respect to the first communication slits (85A) and at positions shifted in the radial direction with respect to the first surface (51); Includes.

[0055] According to the above configuration (11), the eddy current path (5) along one inner edge (70) that defines the axial hole (86), the first communicating slit (85A), and the second communicating slit (85B) can be effectively extended.

[0056] (12) In some embodiments, in the configuration of (11) above, The communication slits include two second communication slits (84B) that are arranged symmetrically with respect to one first communication slit.

[0057] According to the above configuration (12), a path (5) of eddy current is formed along the inner edge (70) on each of one and the other circumferential sides of the first communicating slit (84A). The portion of the pole piece (32) where eddy currents are generated is prevented from being biased in the circumferential direction, so that an excessive temperature rise in only a specific portion of the pole piece (32) can be prevented.

[0058] (13) In some embodiments, in the configuration of (8) above, The slit (85) is arranged at a position offset in the circumferential direction with respect to the axial hole (86) and includes one or more end face opening slits (83) that open to an end face (53) of the pole piece (32) in the circumferential direction.

[0059] According to the above configuration (13), an inner edge (70) is disposed which defines the axial hole (86) and the communicating slit (84), and another inner edge (70) is disposed which is connected to the inner edge (70) via the first surface (51) and the end surface (53). This makes it possible to effectively extend the path (5) of the eddy current along the inner edge (70).

[0060] (14) In some embodiments, in the configuration of (13), The slit (85) includes two end surface opening slits (83) disposed symmetrically with respect to one communication slit (84).

[0061] According to the above configuration (14), the paths (5) are formed along the inner edges (70) on both circumferential sides of the communication slits (84). The portions of the pole pieces (32) where eddy currents are generated are prevented from being biased in the circumferential direction, and therefore, it is possible to prevent the temperature of only a specific portion of the pole piece (32) from excessively increasing.

[0062] (15) In some embodiments, in any one of the configurations (1) to (14) above, Each of the pole pieces (32) includes an inner edge (70) that defines the air gap (80) throughout its axial extent of the magnetic-geared rotating machine (10).

[0063] According to the above configuration (15), the magnetic-geared rotating machine (10) can reduce eddy currents generated in the pole pieces (32) over the entire range in the axial direction of the magnetic-geared rotating machine (10).

[0064] (16) At least one embodiment of the power generation system (1) of the present invention comprises: Prime mover (2), a magnetic gear generator (10A) for generating electricity by being driven by an input from the prime mover (2); and Equipped with.

[0065] According to the configuration of (16) above, for the reason described in (1) above, a power generation system (1) is realized that can reduce eddy current loss while suppressing interruption of the magnetic path of the stator magnet (22).

[0066] (17) At least one embodiment of the pole piece rotor (30) of the present invention comprises: A plurality of magnetic pole pieces (32) arranged in a circumferential direction; A plurality of the magnetic pole pieces (32) and a plurality of holders (39) arranged alternately in the circumferential direction; Equipped with The pole piece (32) has a radial cross section as follows: an outer edge (60) forming a first surface (51) facing one radial side and a second surface (52) facing the other radial side; one or more inner edges (70) located between the first surface (51) and the second surface (52) in the radial direction so as to be surrounded by the outer edge, the inner edges (70) defining one or more gaps (80) within the pole piece (32); Including, In the radial cross section, a first distance (L1), which is the shortest distance in the radial direction between the first surface (51) and the gap (80), is shorter than a second distance (L2), which is the shortest distance in the radial direction between the second surface (52) and the gap (80).

[0067] According to the configuration of (17) above, for the reason described in (1) above, a pole piece rotor (30) is realized that can reduce eddy current loss while suppressing interruption of the magnetic path of the stator magnet (22).

[0068] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and also includes modifications to the above-described embodiments and appropriate combinations of these modifications.

[0069] In this specification, expressions expressing relative or absolute configuration, such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial," do not only strictly represent such a configuration, but also represent 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 indicating that things are in an equal state, such as "identical," "equal," and "homogeneous," 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 describing shapes such as a rectangular shape or a cylindrical shape do not only refer to shapes such as a rectangular shape or a cylindrical shape in the strict geometric sense, but also refer to shapes that include uneven portions, chamfered portions, etc., to the extent that the same effect is obtained. In addition, in this specification, the expressions "comprise," "include," or "have" a certain element are not exclusive expressions that exclude the presence of other elements. [Explanation of symbols]

[0070] 1: Power generation system 2: Prime mover 10: Magnetic geared rotating machine 20: Stator 22: Stator magnet 30: Pole piece rotor 32:Magnetic pole piece 34: End Ring 35:Electromagnetic steel plate 36: Connecting bar 39: Holder 40: Rotor 42: Rotor magnet 51: 1st page 52: 2nd side 60: Outer edge 70: Inner edge 80 :Void 82: Opening slit 83: End opening slit 84: Connecting slit 84A: First connecting slit 84B: Second connecting slit 85: Slit 86: Axial hole 87: Straight section G1: First air gap G2: Second air gap L1: 1st distance L2: 2nd distance L3: Radial distance

Claims

1. A stator including a plurality of stator magnets arranged in a circumferential direction; a rotor including a plurality of rotor magnets arranged in the circumferential direction, the rotor magnets having a number of magnetic poles smaller than the number of the stator magnets; a pole piece rotor including a plurality of pole pieces arranged in the circumferential direction at a radial position between the stator and the rotor; A magnetic-geared rotating machine comprising: Each of the pole pieces has, in a radial cross section of the magnetic-geared rotating machine: an outer edge defining a first face of the pole piece facing the rotor across a first air gap and a second face of the pole piece facing the stator across a second air gap; one or more inner edges positioned radially between the first surface and the second surface and surrounded by the outer edge, the inner edges defining one or more gaps within the pole piece; Including, In the radial cross section, a first distance, which is the shortest distance in the radial direction between the first surface and the gap, is shorter than a second distance, which is the shortest distance in the radial direction between the second surface and the gap. Magnetic geared rotating machinery.

2. each of the pole pieces includes a plurality of magnetic steel sheets stacked in an axial direction of the magnetic-geared rotating machine; The inner edge includes a pair of straight line portions opposed to each other across the gap in the radial cross section, The width of the gap between the pair of linear portions is four times or less than the thickness of each of the electromagnetic steel sheets.

2. The magnetic-geared rotating machine according to claim 1.

3. each of the pole pieces includes a plurality of magnetic steel sheets stacked in an axial direction of the magnetic-geared rotating machine; The inner edge includes a pair of straight line portions opposed to each other across the gap in the radial cross section, The width of the gap between the pair of linear portions is at least twice the thickness of each of the electromagnetic steel sheets.

3. The magnetic-geared rotating machine according to claim 1 or 2.

4. 4. The magnetic-geared rotating machine of claim 1, wherein the first distance is less than a shortest radial distance from the rotor to the outer edge.

5. 5. A magnetic-geared rotating machine according to claim 1, wherein each of the pole pieces includes one or more slits forming at least a portion of the air gap defined by the inner edge.

6. The magnetic-geared rotating machine according to claim 5 , wherein the slits include one or more open slits that open into the first surface.

7. The pole piece rotor comprises: a pair of end rings positioned on both sides of the plurality of magnetic pole pieces in the axial direction; a plurality of connecting bars extending in the axial direction between the pair of end rings; Equipped with Each of the tie bars is disposed within an axial bore formed in each of the pole pieces as part of the air gap.

7. A magnetic-geared rotating machine according to claim 1.

8. each said pole piece including one or more slits forming at least a portion of said gap defined by said inner edge; The magnetic-geared rotating machine according to claim 7 , wherein the slits include one or more communicating slits that communicate with the axial hole.

9. The communication slit opens to the first surface, The magnetic-geared rotating machine according to claim 8 , wherein the slits include one or more open slits that open into the first surface at positions shifted in the circumferential direction from the communicating slits.

10. The magnetic-geared rotating machine according to claim 9 , wherein the slits include two of the open slits that are arranged symmetrically with respect to one of the communication slits.

11. The communication slit is a first communication slit opening on the first surface; one or more second communication slits arranged at positions shifted in the circumferential direction with respect to the first communication slit and at positions shifted in the radial direction with respect to the first surface; 9. The magnetic-geared rotating machine of claim 8, comprising:

12. The magnetic-geared rotating machine according to claim 11 , wherein the communication slits include two of the second communication slits that are arranged symmetrically with respect to one of the first communication slits.

13. The slit is disposed at a position offset in the circumferential direction with respect to the axial hole, and has one or more end face opening slits that open into the end faces of the pole pieces in the circumferential direction.

9. The magnetic-geared rotating machine of claim 8, comprising:

14. The magnetic-geared rotating machine according to claim 13 , wherein the slits include two of the end face opening slits that are arranged at positions symmetrical to each other with one of the communication slits therebetween.

15. 15. A magnetic-geared rotating machine according to claim 1, wherein each pole piece includes an inner edge that defines the air gap throughout its axial extent.

16. The prime mover, A magnetic-geared rotating machine according to any one of claims 1 to 15, as a magnetic gear generator for generating electricity by being driven by an input from the prime mover. A power generation system comprising:

17. A plurality of magnetic pole pieces arranged in a circumferential direction; A plurality of holders arranged alternately with a plurality of the magnetic pole pieces in the circumferential direction; Equipped with The pole pieces, in radial cross section, an outer edge forming a first surface facing one radial side and a second surface facing the other radial side; one or more inner edges located between the first surface and the second surface in the radial direction and surrounded by the outer edge, the inner edges defining one or more gaps within the pole piece; Including, In the radial cross section, a first distance, which is the shortest distance in the radial direction between the first surface and the gap, is shorter than a second distance, which is the shortest distance in the radial direction between the second surface and the gap. Pole piece rotor.

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