Magnetic gear device

Abstract

In the present invention, a magnetic gear device (1) comprises a first magnet (11) in which a plurality of first magnetic poles (111) are disposed in the circumferential direction (C), a second magnet (12) in which a plurality of second magnetic poles (121) are disposed in the circumferential direction (C), a first pole piece (13) that is positioned between the first magnet (11) and the second magnet (12) in the radial direction (R) and that magnetically connects the first magnet (11) and the second magnet (12), a third magnet (14) in which a plurality of third magnetic poles (141) are disposed in the circumferential direction (C), a fourth magnet (15) in which a plurality of fourth magnetic poles (151) are disposed in the circumferential direction (C), and a second pole piece (16) that is positioned between the third magnet (14) and the fourth magnet (15) in the radial direction (R) and that magnetically connects the third magnet (14) and the fourth magnet (15). The first magnet (11) and the fourth magnet (15) are connected in the axial direction (A), the fourth magnet (15) rotates together with the first magnet (11), the number of first magnetic poles (111) of the first magnet (11) is greater than the number of second magnetic poles (121) of the second magnet (12), the number of third magnetic poles (141) of the third magnet (14) is greater than the number of fourth magnetic poles (151) of the fourth magnet (15), and at least one of the first to fourth magnets (11‒15) is ring-shaped.

Description

magnetic gear device

[0001] The present invention relates to a magnetic gear device.

[0002] Conventionally, a magnetic gear device has been known that includes an inner magnet in which multiple magnets are arranged in a circumferential direction, and an outer magnet in which multiple magnets are arranged in a circumferential direction, with the outer magnet arranged radially outside the inner magnet (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2022-150601

[0004] However, the technology described in Patent Document 1 leaves room for improvement in terms of simplifying the structure.

[0005] The present invention has been made in view of the above, and has as its object to provide a magnetic gear device that can be simplified in structure.

[0006] In order to solve the above-mentioned problems and achieve the object, the magnetic gear device of the present invention comprises a first magnet having a plurality of first magnetic poles arranged in the circumferential direction, a second magnet having a plurality of second magnetic poles arranged in the circumferential direction, a first pole piece located between the first magnet and the second magnet in the radial direction and magnetically connecting the first magnet and the second magnet, a third magnet having a plurality of third magnetic poles arranged in the circumferential direction, a fourth magnet having a plurality of fourth magnetic poles arranged in the circumferential direction, and a second pole piece located between the third magnet and the fourth magnet in the radial direction and magnetically connecting the third magnet and the fourth magnet, wherein the first magnet and the fourth magnet are connected in the axial direction and the fourth magnet rotates together with the first magnet, the number of first magnetic poles of the first magnet is greater than the number of second magnetic poles of the second magnet and the number of third magnetic poles of the third magnet is greater than the number of fourth magnetic poles of the fourth magnet, and at least one of the first magnet to the fourth magnet is ring-shaped.

[0007] According to one aspect of the magnetic gear device of the present invention, the structure can be simplified.

[0008] FIG. 1 is a cross-sectional view of a power transmission device including a magnetic gear device according to the first embodiment. FIG. 2-1 is a perspective view of the magnetic gear device shown in FIG. 1. FIG. 2-2 is a plan view of a second magnetic gear mechanism included in the magnetic gear device shown in FIG. 1. FIG. 3 is a cross-sectional view of a power transmission device including a magnetic gear device according to a first modified example of the first embodiment. FIG. 4-1 is a perspective view of the magnetic gear device shown in FIG. 3. FIG. 4-2 is a perspective view showing the other axial side. FIG. 5-1 is a plan view of a power transmission device including a magnetic gear device according to a second embodiment. FIG. 5-2 is a perspective view of the magnetic gear device shown in FIG. 5-1. FIG. 6-1 is a plan view of a power transmission device including a magnetic gear device according to a first modified example of the second embodiment. FIG. 6-2 is a perspective view of the magnetic gear device shown in FIG. 6-1. FIG. 7 is a cross-sectional view of a power transmission device according to a third embodiment. FIG. 8 is a front view of an intermediate transmission mechanism included in the power transmission device shown in FIG. 7. FIG. 9 is a cross-sectional view of a power transmission device according to a first modified example of the third embodiment. FIG. 10 is a cross-sectional view of a power transmission device according to a second modified example of the third embodiment. Fig. 11 is a cross-sectional view of a power transmission device according to a third modified example of the third embodiment. Fig. 12 is a front view of an intermediate transmission mechanism provided in the power transmission device shown in Fig. 11. Fig. 13 is a cross-sectional view of a power transmission device according to a fourth embodiment. Fig. 14 is a cross-sectional view of a power transmission device according to a fifth embodiment. Fig. 15 is a plan view of a power transmission device according to a sixth embodiment.

[0009] Magnetic gear devices according to embodiments will be described in detail below with reference to the drawings. Note that the dimensional relationships and ratios of elements in the drawings may differ from the actual situation. The dimensional relationships and ratios may also differ between the drawings.

[0010] [First embodiment] Fig. 1 is a cross-sectional view of a power transmission device 100 including a magnetic gear device 1 according to a first embodiment. Fig. 2-1 is a perspective view of the magnetic gear device 1 shown in Fig. 1. Fig. 2-2 is a plan view of a second magnetic gear mechanism 1β included in the magnetic gear device 1 shown in Fig. 1. For ease of explanation, the motor 2 is omitted from Fig. 2-1. Also, in Fig. 1, the transmission path of the driving force of the motor 2 is indicated by an arrow F1.

[0011] In describing the power transmission device 100 including the magnetic gear device 1 shown in Figures 1, 2-1, and 2-2 according to the embodiment, in order to facilitate understanding of directions, the direction in which the second shaft 17 extends will be referred to as the axial direction A, the direction in which the first magnet 11, the second magnet 12, the third magnet 14, and the fourth magnet 15 rotate will be referred to as the circumferential direction C, and the direction included in a plane perpendicular to the axial direction A, passing through the axis 17o, and perpendicular to the circumferential direction C will be referred to as the radial direction R.

[0012] 1, 2-1, and 2-2 according to this embodiment transmits torque from a first shaft 22, which is an input shaft, to a second shaft 17, which is an output shaft. The power transmission 100 according to this embodiment is arranged so that an axis 22o of the first shaft 22, which is the input shaft, and an axis 17o of the second shaft 17, which is the output shaft, are parallel to each other. The power transmission 100 includes, for example, a magnetic gear device 1 and a motor 2.

[0013] The power transmission device 100 according to the first embodiment amplifies the torque of the first shaft 22 of the motor 2, which is the input shaft, at the second shaft 17, which is the output shaft, and outputs the amplified torque. The power transmission device 100 is housed in a frame (not shown), for example.

[0014] The motor 2 includes, for example, a main body 21 and a first shaft 22 serving as an input shaft. The motor 2 is an electric motor that converts electrical energy supplied from a power source into mechanical energy, which is the rotation of the first shaft 22.

[0015] The main body 21 is fixed to a frame. Inside the main body 21, devices such as a rotor and a stator are housed.

[0016] The first shaft 22 is a so-called shaft and is formed, for example, from a metal member in a columnar or cylindrical shape. The first shaft 22 has an axis 22o and is provided rotatably about the axis 22o with respect to the frame and the main body 21. The first shaft 22 also extends, for example, along the axial direction A.

[0017] When the motor 2 having the above configuration is driven, the first shaft 22 rotates around the axis 22o, and as a result of this rotation, it rotates in the circumferential direction C together with the second back yoke 122 and the second magnet 12 around the axis 17o.

[0018] The magnetic gear device 1 includes, for example, a first magnet 11, a second magnet 12, a first pole piece 13, a third magnet 14, a fourth magnet 15, a second pole piece 16, and a second shaft 17. In the magnetic gear device 1 according to this embodiment, the first magnet 11, the second magnet 12, and the first pole piece 13 form a first magnetic gear mechanism 1α, and the third magnet 14, the fourth magnet 15, and the second pole piece 16 form a second magnetic gear mechanism 1β. In other words, this magnetic gear device 1 is a device in which two-stage magnetic gear mechanisms 1α and 1β are arranged in the axial direction A. More specifically, this magnetic gear device 1 is a device in which the first magnetic gear mechanism 1α and the second magnetic gear mechanism 1β are connected in the axial direction A.

[0019] The first magnetic gear mechanism 1α is disposed on one side of the axial direction A where the first shaft 22, which is the input shaft, is disposed, and the second magnetic gear mechanism 1β is disposed on the other side of the axial direction A where the second shaft 17, which is the output shaft, is disposed.

[0020] The first magnet 11 is provided in the magnetic gear device 1 so as to be rotatable about the axis 17o relative to the frame and the first pole piece 13. The first magnet 11 has a plurality of (e.g., 52) first magnetic poles 111 arranged in the circumferential direction C, and the plurality of first magnetic poles 111 are integrally formed in a ring shape. Furthermore, a first space S1 is formed between the first magnet 11 and the first pole piece 13 in the radial direction R. In other words, the first magnet 11 is provided so as to be rotatable about the axis 17o without contacting the first pole piece 13. Note that the first space S1 may be filled with a non-magnetic material such as a resin sliding material as long as it allows rotation of the first magnet 11 and the first pole piece 13 in a vacuum state or in the presence of a fluid such as air, water, or oil.

[0021] The multiple first magnetic poles 111 are arranged such that north poles and south poles alternate in the circumferential direction C. The multiple first magnetic poles 111 of the first magnet 11 are formed by magnetizing a magnetic material as described below.

[0022] The number of first magnetic poles 111 of the first magnet 11 is greater than the number of second magnetic poles 121 of the second magnet 12. In addition, the first magnet 11 is provided with a first back yoke 112, for example, on the inner side in the radial direction R. In the magnetic gear device 1 according to this embodiment, the first magnet 11 and the second magnet 12 are arranged so as to be rotatable about a common axis 17o.

[0023] 1 and 2-1, the first magnet 11 is formed in a ring shape and has an upward side surface 11b. Furthermore, the first magnet 11 has a through hole 11c and an outer peripheral surface 11d. The first magnet 11 is a rare earth iron-based magnet, and in this embodiment, for example, is formed by mixing magnetic powder containing neodymium (Nd—Fe—B), a magnetically isotropic rare earth iron-based magnet, with a thermosetting resin, such as epoxy resin, in a predetermined ratio.

[0024] The rare earth iron-based magnet before magnetization that is the material for the first magnet 11 is preferably an anisotropic rare earth iron-based magnet with an average crystal grain size of 10 nm or more and 10,000 nm or less, and more preferably an anisotropic rare earth iron-based magnet with an average crystal grain size of 10 nm or more and 6,600 nm or less.

[0025] The first magnet 11 is formed by magnetizing the object to be magnetized, which is the rare earth iron-based magnet described above before magnetization, by raising the temperature of the object to be magnetized from below the Curie point to above the Curie point, and then lowering the temperature from above the Curie point to below the Curie point while a magnetizing magnetic field is applied by the field magnet section.

[0026] Furthermore, in response to the miniaturization and high-resolution of devices (e.g., magnetic encoders) used, if the permanent magnet to be magnetized is composed of a rare-earth magnet with high magnetic properties (e.g., a Nd bonded magnet), the conventional pulse current coil current method requires a larger current to be passed, which can lead to problems such as larger and more expensive magnetization devices.In contrast, the first magnet 11 shown in this embodiment is formed from the object to be magnetized by heating the object to be magnetized using a heating unit and lowering the temperature from a temperature above the Curie point of the magnetic powder that makes up the object to be magnetized to a temperature below the Curie point, while continuing to generate a magnetic field using the permanent magnet in the field magnet unit, thereby performing multi-pole magnetization (see, for example, JP 2021-93521 A).

[0027] Forming the first magnet 11 in this manner makes it possible to achieve uniformity in the magnetization characteristics of the object to be magnetized. Furthermore, forming the first magnet 11 in the above manner makes it possible to narrow the pitch of the multiple first magnetic poles 111 in the circumferential direction C (for example, 3 mm or less in the circumferential direction C). In particular, when the first magnet 11 with a large number of first magnetic poles is arranged inside in the radial direction R relative to the second magnet 12 with a small number of second magnetic poles 121, as in this embodiment, the pitch of the first magnetic poles 111 needs to be narrower. Note that the pitch of the first magnetic poles 111 is measured on the outer periphery of the first magnet 11.

[0028] The second magnet 12 is provided rotatably about the axis 17o relative to the frame and the first pole piece 13. Furthermore, a second space S2 is formed between the second magnet 12 and the first pole piece 13 in the radial direction R. In other words, the second magnet 12 is provided rotatably about the axis 17o without contacting the first pole piece 13. The second magnet 12 is formed in the same manner as the first magnet 11. That is, the second magnet 12 has multiple (six) second magnetic poles 121 arranged in the circumferential direction C, and the multiple second magnetic poles 121 are formed integrally in a ring shape. Furthermore, the multiple second magnetic poles 121 are arranged so that north poles and south poles alternate in the circumferential direction C. Furthermore, the second magnet 12 has a second back yoke 122 provided on the outer side of the second magnetic poles 121 in the radial direction R. The second back yoke 122 is fixed to the first shaft 22. The second space S2 may be filled with a non-magnetic material such as a resin sliding material, as long as it allows the second magnet 12 and the first pole piece 13 to rotate when in a vacuum state or when a fluid such as air, water, or oil is present.

[0029] The first pole piece 13 is composed of a plurality of (e.g., 17) first modulation pieces 131 and modulates the magnetic flux of the magnets 11, 12. The first pole piece 13 is located between the first magnet 11 and the second magnet 12 in the radial direction R and magnetically connects the first magnet 11 and the second magnet 12. The first modulation pieces 131 are formed, for example, from a magnetic material, are arranged at equal intervals along the circumferential direction C, and are fixed to a frame (not shown).

[0030] In the magnetic gear device 1 according to this embodiment, the number of pole pairs 11M of the first magnet 11 is 26, the number of pole pairs 12M of the second magnet 12 is 3, and the number of modulation pieces 131 of the pole piece 13 is 29. Therefore, when the second magnet 12 on the outside in the radial direction R is used as the input, the first magnet 11 on the inside in the radial direction R is used as the output, and the pole piece 13 is fixed, the reduction ratio X1 can be calculated as follows: X1 = 11M ÷ 12M = 26 ÷ 3 = 8.67

[0031] Alternatively, when the second magnet 12 is the input, the pole piece 13 is the output, the first magnet 11 is fixed, and the second magnet 12 is placed on the input side, the reduction ratio X2 can be calculated as follows: X2 = 13M ÷ 12M = 29 ÷ 3 = 9.67

[0032] The first magnetic gear mechanism 1α includes a first magnet 11, a second magnet 12, and a first pole piece 13, which are formed separately.

[0033] In the first magnetic gear mechanism 1α, the second magnet 12 is disposed on the outside in the radial direction R, and the first magnet 11 is disposed on the inside in the radial direction R of the second magnet 12.

[0034] The first magnetic gear mechanism 1α is a so-called flux modulation type magnetic gear (harmonic type magnetic gear device) in which, when the second back yoke 122 and second magnet 12 connected to the driving side rotate in the circumferential direction XC around the axis 17o, the change in magnetic flux of the multiple second magnetic poles 121 is modulated by the first pole piece 13 and transmitted to the first magnetic pole 111 of the first magnet 11 connected to the driven side, causing the first magnet 11 to rotate around the axis 17o.

[0035] In the first magnetic gear mechanism 1α, the number of first magnetic poles 111 of the first magnet 11 arranged on the inside of the second magnet 12 in the radial direction R is greater than the number of second magnetic poles 121 of the second magnet 12. Therefore, when the first magnetic gear mechanism 1α is operated, the rotation speed in the circumferential direction C decreases, but the torque can be increased. Furthermore, in the first magnetic gear mechanism 1α, the first magnet 11 has multiple first magnetic poles 111 arranged in the circumferential direction C and is ring-shaped with the multiple first magnetic poles 111 integrally formed. Therefore, compared to a magnetic gear device including a ring-shaped first magnet formed by connecting multiple individually formed magnets (e.g., the device described in JP 2022-150601 A), the pitch of the multiple first magnetic poles 111 in the circumferential direction C can be narrowed, and the torque can be increased.

[0036] Furthermore, in the first magnetic gear mechanism 1α, the first magnet 11 and the first pole piece 13 are not in contact with each other in the radial direction R, and the first pole piece 13 and the second magnet 12 are not in contact with each other in the radial direction R. Furthermore, in the first magnetic gear mechanism 1α, the first pole piece 13 is disposed between the first magnet 11 and the second magnet 12 in the radial direction R, and the first magnet 11 and the second magnet 12 are magnetically coupled by the first pole piece 13. Therefore, when a torque equal to or greater than the maximum transmission torque determined by the magnetic force of the second magnetic pole 121 and the gap between the second magnet 12 and the first pole piece 13 in the radial direction R is applied to the first magnetic gear mechanism 1α, the first magnetic gear mechanism 1α functions as a torque limiter, and rotation of the first magnet 11 in the circumferential direction C is stopped even when the second magnet 12 is rotating in the circumferential direction C. Therefore, the first magnetic gear mechanism 1α can protect the motor 2 by separating the drive side from the driven side in the event of an overload. Alternatively, if unintended torque is generated by the motor 2, the first magnetic gear mechanism 1α can function as a torque limiter, separating the drive side from the driven side, thereby protecting the load side. Furthermore, when the magnetic gear device 1 is used in an electric opening / closing mechanism for a home appliance, it can also function as a safety device that minimizes impact on the human body by cutting off torque from the drive side when a member on the load side comes into contact with the human body.

[0037] The third magnet 14 is rotatable about the axis 17o relative to the frame and the second pole piece 16. Furthermore, a third space S3 is formed between the third magnet 14 and the second pole piece 16 in the radial direction R. In other words, the third magnet 14 is rotatable about the axis 17o without contacting the second pole piece 16. The third magnet 14 is formed in the same manner as the first magnet 11. That is, the third magnet 14 has a plurality (52 pieces) of third magnetic poles 141 arranged in the circumferential direction C, and the plurality of third magnetic poles 141 are formed integrally in a ring shape. Furthermore, the plurality of third magnetic poles 141 are arranged so that north poles and south poles alternate in the circumferential direction C. Furthermore, a third back yoke 142 is provided on the third magnet 14, for example, on the outer side in the radial direction R. The third space S3 may be filled with a non-magnetic material such as a resin sliding material, as long as it allows the third magnet 14 and the second pole piece 16 to rotate when in a vacuum state or when a fluid such as air, water, or oil is present.

[0038] The fourth magnet 15 is rotatable about the axis 17o relative to the frame and the second pole piece 16. Furthermore, a fourth space S4 is formed between the fourth magnet 15 and the second pole piece 16 in the radial direction R. In other words, the fourth magnet 15 is rotatable about the axis 17o without contacting the second pole piece 16. The fourth magnet 15 is formed in the same manner as the first magnet 11. That is, the fourth magnet 15 has multiple (six) fourth magnetic poles 151 arranged in the circumferential direction C, and the multiple fourth magnetic poles 151 are integrally formed in a ring shape. Furthermore, the multiple fourth magnetic poles 151 are arranged so that north poles and south poles alternate in the circumferential direction C. Furthermore, the fourth magnet 15 is provided with a fourth back yoke 152, for example, on the inner side in the radial direction R. In the magnetic gear mechanism 1β according to this embodiment, the third magnet 14 and the fourth magnet 15 are arranged so as to be rotatable about the common axis 17o. The fourth space S4 may be filled with a non-magnetic material such as a resin sliding material, as long as it allows the rotation of the fourth magnet 15 and the second pole piece 16 in a vacuum state or when a fluid such as air, water, or oil is present.

[0039] The second pole piece 16 is composed of a plurality of (e.g., 17) second modulation pieces 161 and modulates the magnetic flux of the magnets 14, 15. The second pole piece 16 is located between the third magnet 14 and the fourth magnet 15 in the radial direction R, and magnetically connects the third magnet 14 and the fourth magnet 15. The second modulation pieces 161 are formed, for example, from a magnetic material, are arranged at equal intervals along the circumferential direction C, and are fixed to a frame (not shown).

[0040] The second shaft 17 is a so-called shaft and is formed, for example, from a metal member in a columnar or cylindrical shape. The second shaft 17 has an axis 17o and is provided to the frame so as to be rotatable about the axis 17o. The second shaft 17 is formed, for example, integrally with the third back yoke 142 and rotates in the circumferential direction C together with the third magnet 142. The magnetic gear device 1 outputs torque to the outside as the second shaft 17 rotates in the circumferential direction C about the axis 17o.

[0041] Furthermore, in the magnetic gear device 1 according to this embodiment, the first back yoke 111 and the fourth back yoke 152 are integrally formed.

[0042] Furthermore, in the magnetic gear device 1, the first magnet 11 and the fourth magnet 15 are formed integrally. In other words, in this magnetic gear device 1, the first magnet 11 and the fourth magnet 15 are connected in the axial direction A, and the fourth magnet 15 rotates together with the first magnet 11. To explain the first magnet 11 and the fourth magnet 15 more specifically, by using a ring-shaped magnetic body and magnetizing the magnetic body as described above, the first magnet 11 is formed on one side in the axial direction A, and the fourth magnet 15 is formed on the other side in the axial direction A. As a result, an unmagnetized intermediate portion IM1 is formed between the first magnet 11 and the fourth magnet 15 in the axial direction A.

[0043] In addition, in the axial direction A of the magnetic gear device 1, the second magnet 12 and the third magnet 14 are arranged opposite each other with a fifth space S5 interposed therebetween so as not to be affected by each other's magnetic forces.

[0044] The second magnetic gear mechanism 1β includes a third magnet 14, a fourth magnet 15, and a second pole piece 16, which are formed separately.

[0045] In the second magnetic gear mechanism 1β, the third magnet 14 is disposed on the outer side in the radial direction R, and the fourth magnet 15 is disposed on the inner side in the radial direction R of the third magnet 14 .

[0046] The second magnetic gear mechanism 1β is a so-called flux modulation type magnetic gear (harmonic type magnetic gear device) in which, when the fourth magnet 15 formed integrally with the first magnet 11 rotates together with the first magnet 11 in the circumferential direction XC around the axis 17o, the change in magnetic flux of the multiple fourth magnetic poles 151 is modulated by the second pole piece 16 and transmitted to the third magnetic pole 141 of the third magnet 14 connected to the driven side, causing the third magnet 14 to rotate around the axis 17o.

[0047] In the second magnetic gear mechanism 1β, the number of third magnetic poles 141 of the third magnet 14 arranged outside the fourth magnet 15 in the radial direction R is greater than the number of fourth magnetic poles 151 of the fourth magnet 15. Therefore, when the second magnetic gear mechanism 1β is operated, the rotation speed in the circumferential direction C decreases, but torque can be increased. In other words, the magnetic gear device 1 according to this embodiment can increase torque by using the two-stage magnetic gear mechanisms 1α and 1β. Furthermore, in the second magnetic gear mechanism 1β, the third magnet 14 has multiple third magnetic poles 141 arranged in the circumferential direction C, and the multiple third magnetic poles 141 are integrally formed in a ring shape. Therefore, compared to a magnetic gear device including a ring-shaped first magnet formed by connecting multiple individually formed magnets (for example, the device described in JP 2022-150601 A), the second magnetic gear mechanism 1β can increase torque because the pitch of the multiple third magnetic poles 141 in the circumferential direction C can be narrowed.

[0048] In the second magnetic gear mechanism 1β, the third magnet 14 and the second pole piece 16 are not in contact with each other in the radial direction R, and the second pole piece 16 and the fourth magnet 15 are not in contact with each other in the radial direction R. Furthermore, in the second magnetic gear mechanism 1β, the second pole piece 16 is disposed between the third magnet 14 and the fourth magnet 15 in the radial direction R, and the third magnet 14 and the fourth magnet 15 are magnetically coupled by the second pole piece 16. Therefore, when a torque equal to or greater than the maximum transmission torque set by the magnetic force of the fourth magnetic pole 151 and the gap between the fourth magnet 15 and the second pole piece 16 in the radial direction R is applied to the second magnetic gear mechanism 1β, the second magnetic gear mechanism 1β functions as a torque limiter, and rotation of the third magnet 14 in the circumferential direction C is stopped even when the fourth magnet 15 is rotating in the circumferential direction C. Therefore, the second magnetic gear mechanism 1β can protect the motor 2 by separating the drive side from the driven side in the event of an overload. Alternatively, if unintended torque is generated by the motor 2, the second magnetic gear mechanism 1β can function as a torque limiter, separating the drive side from the driven side, thereby protecting the load side. Furthermore, when the magnetic gear device 1 is used in an electric opening / closing mechanism for a home appliance, it can also function as a safety device that minimizes impact on the human body by cutting off torque from the drive side when a member on the load side comes into contact with the human body.

[0049] In the first magnetic gear mechanism 1α according to this embodiment, the number of second magnetic poles 121 of the second magnet 12 located on the input side is 6, and the number of second magnetic poles 121 of the first magnet 11 located on the output side is 52. Therefore, the reduction ratio X1 of the first magnetic gear mechanism 1α is calculated as follows: X1 = (52 ÷ 2) / (6 ÷ 2) = 8.67

[0050] In the second magnetic gear mechanism 1β according to this embodiment, the number of fourth magnetic poles 151 of the fourth magnet 15 located on the input side is six, and the number of third magnetic poles 141 of the third magnet 14 located on the output side is 52. Therefore, the reduction ratio X2 of the first magnetic gear mechanism 1α is calculated as follows: X2 = (52 ÷ 2) / (6 ÷ 2) = 8.67

[0051] Therefore, the reduction ratio of the magnetic gear device 1 according to this embodiment is calculated as follows: 8.67×8.67=75.2

[0052] As described above, the magnetic gear device 1 according to this embodiment has the following configuration: The magnetic gear device 1 includes a first magnet 11 having a plurality of first magnetic poles 111 arranged in the circumferential direction C, a second magnet 12 having a plurality of second magnetic poles 121 arranged in the circumferential direction C, a first pole piece 13 located between the first magnet 11 and the second magnet 12 in the radial direction R and magnetically connecting the first magnet 11 and the second magnet 12, a third magnet 14 having a plurality of third magnetic poles 141 arranged in the circumferential direction C, a fourth magnet 15 having a plurality of fourth magnetic poles 151 arranged in the circumferential direction C, and a second pole piece 16 located between the third magnet 14 and the fourth magnet 15 in the radial direction R and magnetically connecting the third magnet 14 and the fourth magnet 15. In the magnetic gear device 1, the first magnet 11 and the fourth magnet 15 are connected in the axial direction A. The fourth magnet 15 rotates together with the first magnet 11. The number of first magnetic poles 111 of the first magnet 11 is greater than the number of second magnetic poles 121 of the second magnet 12, and the number of third magnetic poles 141 of the third magnet 14 is greater than the number of fourth magnetic poles 151 of the fourth magnet 15. Furthermore, in the magnetic gear device 1, at least one of the four magnets, the first magnet 11 to the fourth magnet 15, is ring-shaped. Therefore, the magnetic gear device 1 according to this embodiment does not need to form the magnets 11, 12, 13, and 14 by connecting multiple magnets, thereby simplifying the structure. Furthermore, the magnetic gear device 1 can increase the torque of the second shaft 17 (output torque) more than the torque of the first shaft 22 (input torque). Furthermore, in the magnetic gear device 1 according to this embodiment, the first magnet 11 and the first pole piece 13 are not in contact with each other in the radial direction R, the first pole piece 13 and the second magnet 12 are not in contact with each other in the radial direction R, the third magnet 14 and the second pole piece 16 are not in contact with each other, and the second pole piece 16 and the fourth magnet 15 are not in contact with each other in the radial direction R. This reduces the noise generated during operation, prevents dust from being generated during use, and eliminates the need for lubricating oil.Furthermore, the magnetic gear device 1 does not require maintenance because it does not generate dust during use and does not require the use of lubricating oil. Furthermore, compared to a magnetic gear device in which the outer circumferential surfaces of the ring-shaped first magnets and the ring-shaped second magnets are opposed and magnetically coupled only by the opposed magnets, the magnetic gear device 1 according to this embodiment magnetically couples the first magnetic poles 111 of the plurality of first magnets 11 to the second magnetic poles 121 of the plurality of second magnets 12 with the first pole piece 13 interposed in the radial direction R, and also magnetically couples the third magnetic poles 141 of the plurality of third magnets 14 to the fourth magnetic poles 151 of the plurality of fourth magnets 15 with the second pole piece 16 interposed in the radial direction R, thereby increasing torque density.

[0053] In the magnetic gear device 1 according to this embodiment, the first magnet 11 has a plurality of first magnetic poles 111 integrally formed, and the third magnet 14 has a plurality of third magnetic poles 141 integrally formed. This allows for a smaller and lighter magnetic gear device compared to a magnetic gear device including a ring-shaped magnet formed by connecting individually formed magnets in the circumferential direction C. Furthermore, because the magnetic gear device 1 includes the first magnet 11 and third magnet 14 having the above-described configuration, it is possible to reduce the number of parts, simplify the shape of the back yokes 112, 122, 142, 152 and / or the frame, and eliminate the need for covers to prevent the first magnetic poles 111 and the third magnetic poles 141 from falling off. Furthermore, since the first magnet 11 has a narrow pitch between the plurality of first magnetic poles 111 in the circumferential direction C, torque ripple can be reduced. Furthermore, since the third magnet 14 has a narrow pitch between the plurality of third magnetic poles 141 in the circumferential direction C, torque ripple can be reduced.

[0054] In the magnetic gear device 1 according to this embodiment, the first magnet 11 and the fourth magnet 15 are integrally formed. Therefore, the magnetic gear device 1 according to this embodiment can improve workability during assembly by reducing the number of parts compared to a magnetic gear device in which the first magnet 11 and the fourth magnet 15 are formed separately.

[0055] Because the magnetic gear device 1 according to this embodiment has the above-mentioned functions and effects, it can be applied, for example, to devices used in clean rooms where dust generation is undesirable, devices used in special environments such as marine or aerospace environments, residential equipment and home appliances that require safety measures against contact with the human body and measures against overload, and, taking advantage of its high efficiency, to generators, etc. More specifically, the magnetic gear device 1 can be applied to robot arms, semiconductor manufacturing equipment, electric opening and closing mechanisms and electronic locks of home appliances, cooling pumps and cooling fans for air conditioners, etc.

[0056] In the magnetic gear device 1 according to this embodiment, the first magnet 11 is arranged inside the second magnet 12 in the radial direction R. In the magnetic gear device 1 according to this embodiment, the ring-shaped first magnet 11 is formed by integrally forming a plurality of first magnetic poles 111 by magnetizing the magnetic material as described above, so the ring-shaped first magnet 11 can be arranged even with a narrow pitch on the inside in the radial direction R. In addition, the third magnet 14 is arranged outside the fourth magnet 15 in the radial direction R.

[0057] Although the magnetic gear device 1 described above has the first magnet 11 and the fourth magnet 15 formed integrally, the magnetic gear device 1 according to this embodiment is not limited to this. For example, the first magnet 11 and the fourth magnet 15 may be formed separately, and a separate ring-shaped connecting portion may be formed in place of the intermediate portion IM1, and the first magnet 11 and the fourth magnet 15 may be connected in the axial direction A via the connecting portion.

[0058] Furthermore, the input and output may be arranged in reverse in the magnetic gear device 1 described above. In this case, the torque on the output side decreases, but the speed (the rotational speed of the output shaft in the circumferential direction C) can be increased.

[0059] Furthermore, in the magnetic gear device 1 according to the embodiment described above, the second magnet 12 is on the input side, the first pole piece 13 is fixed, the second pole piece 16 is fixed, and the third magnet 14 is on the output side. However, the magnetic gear device 1 according to this embodiment is not limited to this. For example, as shown in Table 1, the input side, output side, and fixing points can be changed as appropriate.

[0060] In the above-described embodiment, the power transmission device 100 is described as including the magnetic gear device 1 and the motor 2. However, the power transmission device 100 according to this embodiment is not limited to this. For example, an intermediate transmission mechanism 3 made up of mechanical gears may be disposed between the motor 2 and the magnetic gear device 1. Furthermore, the motor 2 may be replaced with a generator. Furthermore, the driving source may be something other than the motor 2.

[0061] Furthermore, the magnets 11, 12, 13, and 14 are described as being provided with back yokes 112, 122, 142, and 152. However, the back yokes 112, 122, 142, and 152 do not necessarily have the function of a back yoke, as long as they can connect (fix) the magnets 11, 12, 13, and 14 to other components.

[0062] In the magnetic gear device 1 according to the embodiment described above, the first magnet 11 has been described as having 52 first magnetic poles 111 (26 pole pairs). However, the number of first magnetic poles 111 of the first magnet 11 according to this embodiment is not limited to this and can be set to any number. The same applies to the third magnet 14.

[0063] Furthermore, in the magnetic gear device 1 according to the embodiment described above, the second magnet 12 has been described as having six second magnetic poles 121 (three pole pairs). However, the number of second magnetic poles 121 of the second magnet 12 according to the present embodiment is not limited to this and can be set to any number. The same applies to the fourth magnet 15.

[0064] Furthermore, in the magnetic gear device 1 according to the embodiment described above, the first pole piece 13 has been described as being composed of 17 first modulation pieces 131. However, the number of first modulation pieces 131 constituting the first pole piece 13 according to this embodiment is not limited to this and can be set to any number. Note that if any two of the numbers of the first magnetic poles 111 of the first magnet, the second magnetic poles 121 of the second magnet, and the modulation pieces 131 of the pole piece 13 are determined, the number of the remaining one is set appropriately depending on the numbers of the other two. The same applies to the second pole piece 16.

[0065] Furthermore, in the magnetic gear device 1 according to the above-described embodiment, the second magnet 12 has been described as having a plurality of second magnetic poles 121 arranged in the circumferential direction C, and the plurality of second magnetic poles 121 formed integrally in a ring shape. However, the second magnet 12 according to this embodiment can also be formed by joining a plurality of magnets each formed in an arc shape and having two second magnetic poles 121. The same applies to the first magnet 11, the third magnet 14, and the fourth magnet 15.

[0066] Furthermore, in the magnetic gear device 1 according to the embodiment described above, two-stage magnetic gear mechanisms 1α and 1β are arranged in the axial direction A. However, the magnetic gear device 1 according to this embodiment is not limited to this. For example, the magnetic gear device 1 may have three or more stages of magnetic gear mechanisms arranged in the axial direction A.

[0067] Furthermore, in the magnetic gear device 1 according to the embodiment described above, the input and output shafts can be interchanged, for example by connecting the first shaft 22 of the motor 2 to the third magnet 14 to serve as the input shaft and the second magnet 12 to serve as the output shaft. In this case, torque decreases, but speed can be improved. In addition, in the first magnetic gear mechanism 1α in this case, if the first magnet 11 on the inside in the radial direction R serves as the input, the second magnet 12 on the outside in the radial direction R serves as the output, and the pole piece 13 is fixed, the speed increase ratio X3 can be calculated as follows: X3 = 11M ÷ 12M = 26 ÷ 3 = 8.67

[0068] Alternatively, in this case, in the first magnetic gear mechanism 1α, if the pole piece 13 is the output, the first magnet 11 is the input, and the second magnet 12 is fixed, the speed increase ratio X4 can be calculated as follows: X4 = 13M ÷ 12M = 29 ÷ 3 = 9.67

[0069] Furthermore, for example, in the magnetic gear mechanism 1α according to the above embodiment, if the first magnet 11 and the second magnet 12 are interchanged, with the first magnet 11 on the outside in the radial direction R and the second magnet 12 on the inside in the radial direction R, the first shaft 22 of the motor 2 is connected to the second magnet 12 to serve as the input shaft, the first magnet 11 is the output shaft, and the pole piece 13 is fixed, the reduction ratio X5 can be calculated as follows: X5 = 11M ÷ 12M = 26 ÷ 3 = 8.67

[0070] Alternatively, in this case, in the first magnetic gear mechanism 1α, if the pole piece 13 is the output, the first magnet 11 is fixed, and the second magnet 12 is the input, the reduction ratio X6 can be calculated as follows: X6 = 13M ÷ 12M = 29 ÷ 3 = 9.67

[0071] [First Modification of First Embodiment] Next, a magnetic gear device 1A according to a first modification of the first embodiment will be described using FIGS. 3, 4-1, and 4-2. FIG. 3 is a cross-sectional view of a power transmission device 100A including the magnetic gear device 1A according to the first modification of the first embodiment. FIG. 4-1 is a perspective view of the magnetic gear device 1A shown in FIG. 3. FIG. 4-2 is a perspective view showing the other side in the axial direction A. Note that in the configuration of the magnetic gear device 1A according to the first modification of the first embodiment, the same components as those in the magnetic gear device 1 according to the first embodiment are assigned the same reference numerals and their description will be omitted. In addition, in FIG. 3, the transmission path of the driving force of the motor 2 is indicated by arrow F2.

[0072] The magnetic gear device 1A includes a first magnetic gear mechanism 1α and a second magnetic gear mechanism 1β. The magnetic gear device 1A further includes a second shaft 17. The magnetic gear device 1A is a device in which the first magnetic gear mechanism 1α and the second magnetic gear mechanism 1β are connected in the axial direction A.

[0073] The first magnetic gear mechanism 1α is composed of a first magnet 11, a second magnet 12, and a first pole piece 13.

[0074] In the first magnetic gear mechanism 1α, the first magnet 11 is disposed on the outer side of the second magnet 12 in the radial direction R. The first back yoke 112 is disposed on the outer side of the first magnet 11 in the radial direction R. The first magnet 11 according to this modification is disposed on the output side (driven side) of the second magnet 12.

[0075] In the first magnetic gear mechanism 1α, the second magnet 12 is disposed inside the first magnet 11 in the radial direction R, and the first shaft 22 is fixed to the tip of the second back yoke 122 in the axial direction A. In other words, the second magnet 12 according to this modification is disposed on the input side (drive side) of the first magnet 11.

[0076] The second magnetic gear mechanism 1β is composed of a third magnet 14, a fourth magnet 15, and a second pole piece 16.

[0077] In the second magnetic gear mechanism 1β, the third magnet 14 is disposed on the inside of the fourth magnet 15 in the radial direction R. The third back yoke 142 is disposed on the inside of the third magnet 14 in the radial direction R. The third back yoke 142 is then connected to the second shaft 17. In other words, the third magnet 14 according to this modification is disposed on the output side (driven side) of the fourth magnet 15.

[0078] In the second magnetic gear mechanism 1β, the fourth magnet 15 is disposed on the outside of the third magnet 14 in the radial direction R, and the fourth back yoke 152 is disposed on the outside of the fourth magnet 15 in the radial direction R. The fourth magnet 15 according to this modification is disposed on the input side (drive side) of the third magnet 14.

[0079] In the power transmission device 100A according to this modified example, when the first shaft 22 is rotated in the circumferential direction C by driving the motor 2, the second back yoke 122 and the second magnet 12 fixed to the first shaft 22 rotate in the circumferential direction C together with the first shaft 22. Then, a change in the magnetic flux of the second magnetic pole 121 of the second magnet 12 is modulated by the first pole piece 13 and transmitted to the first magnetic pole 111 of the first magnet 11. Therefore, as the second magnet 12 rotates in the circumferential direction C, the first magnet 11 rotates in the circumferential direction C. Then, because the first magnet 11 and the fourth magnet 15 are integrally formed, the fourth magnet 15 rotates in the circumferential direction C as the first magnet 11 rotates in the circumferential direction C. Then, a change in the magnetic flux of the fourth magnetic pole 151 of the fourth magnet 15 is modulated by the second pole piece 16 and transmitted to the third magnetic pole 141 of the third magnet 14. Since the second shaft 17 is fixed to the third magnet 14, the second shaft 17 rotates in the circumferential direction C together with the rotation of the third magnet 14 in the circumferential direction C.

[0080] In the magnetic gear device 1A according to this modification, the first magnet 11 is arranged outside the second magnet 12 in the radial direction R, and the third magnet 14 is arranged inside the fourth magnet 15 in the radial direction R. Furthermore, the magnetic gear device 1A according to this modification achieves the same actions and effects as the magnetic gear device 1 according to the first embodiment.

[0081] In the magnetic gear device 1A according to the above-described modified example, two-stage magnetic gear mechanisms 1α and 1β are arranged in the axial direction A. However, the magnetic gear device 1A according to this modified example is not limited to this. For example, the magnetic gear device 1A may have three or more stages of magnetic gear mechanisms arranged in the axial direction A.

[0082] Furthermore, in the magnetic gear device 1A according to the above-described modified example, the second magnet 12 is on the input side, the first pole piece 13 is fixed, the second pole piece 16 is fixed, and the third magnet 14 is on the output side. However, the magnetic gear device 1A according to this modified example is not limited to this. For example, as shown in Table 2, the input side, output side, and fixing points can be changed as appropriate.

[0083] Second Embodiment Next, a magnetic gear device 1B according to a second embodiment will be described with reference to FIGS. 5-1 and 5-2. FIG. 5-1 is a plan view of a power transmission device 100B including the magnetic gear device 1B according to the second embodiment. FIG. 5-2 is a perspective view of the magnetic gear device 1B shown in FIG. 5-1. Note that in the configuration of the power transmission device 100B according to the second embodiment, the same components as those in the power transmission device 100 according to the first embodiment are assigned the same reference numerals and their description will be omitted. Also, the motor 2 and intermediate transmission mechanism 3B are omitted in FIG. 5-2.

[0084] The power transmission device 100B according to this embodiment includes a motor 2, an intermediate transmission mechanism 3B, and a magnetic gear device 1B.

[0085] The intermediate transmission mechanism 3B includes, for example, a first gear 31B which is a worm and a second gear 32B which is a worm wheel.

[0086] The first gear 31B is fixed to the tip of the first shaft 22 in the first direction D, and rotates together with the rotation of the first shaft 22.

[0087] The second gear 32B is formed to rotate together with the second magnet 12 of the magnetic gear device 1B in the circumferential direction C. The second gear 32B meshes with the first gear 31B. The intermediate transmission mechanism 3B according to this embodiment is formed by the mechanical first gear 31B and second gear 32B.

[0088] The magnetic gear device 1B includes a first magnetic gear mechanism 1α and a second magnetic gear mechanism 1β. The magnetic gear device 1B is also provided with a second shaft 17. The magnetic gear device 1 is a device in which the first magnetic gear mechanism 1α and the second magnetic gear mechanism 1β are connected in the radial direction R.

[0089] The first magnetic gear mechanism 1α is composed of a first magnet 11, a second magnet 12, and a first pole piece 13.

[0090] In the first magnetic gear mechanism 1α, the first magnet 11 is disposed inside the second magnet 12 in the radial direction R. The first magnet 11 according to this embodiment does not have a back yoke. The first magnet 11 according to this embodiment is disposed on the output side (driven side) of the second magnet 12.

[0091] In the first magnetic gear mechanism 1α, the second magnet 12 is disposed on the outer side of the first magnet 11 in the radial direction R. The second back yoke 122 is also disposed on the outer side of the second magnet 12 in the radial direction R, and the outer peripheral surface of the second back yoke 122 is fixed to the inner peripheral surface of the second gear 32B in the radial direction R. The second magnet 12 according to this embodiment is also disposed on the input side (drive side) of the first magnet 11.

[0092] The second magnetic gear mechanism 1β is composed of a third magnet 14, a fourth magnet 15, and a second pole piece 16.

[0093] In the second magnetic gear mechanism 1β, the third magnet 14 is disposed on the inside of the fourth magnet 15 in the radial direction R. The third back yoke 142 is disposed on the inside of the third magnet 14 in the radial direction R, and the inner circumferential surface of the third back yoke 142 is fixed to the outer circumferential surface of the second shaft 17 in the radial direction R. In other words, the third magnet 14 according to this embodiment is disposed on the output side (driven side) with respect to the fourth magnet 15.

[0094] In the second magnetic gear mechanism 1β, the fourth magnet 15 is arranged outside the third magnet 14 in the radial direction R. The fourth magnet 15 according to this embodiment does not have a back yoke. The fourth magnet 15 according to this embodiment is arranged on the input side (drive side) of the third magnet 14. In the magnetic gear device 1B according to this embodiment, the first magnet 11, the second magnet 12, the third magnet 14, and the fourth magnet 15 are arranged so as to be rotatable around a common axis 17o.

[0095] Furthermore, in the power transmission device 100B according to this embodiment, the first magnet 11 and the fourth magnet 15 are formed integrally. In other words, in this magnetic gear device 1, the first magnet 11 and the fourth magnet 15 are connected in the radial direction R, and the fourth magnet 15 rotates together with the first magnet 11. To explain the first magnet 11 and the fourth magnet 15 more specifically, a ring-shaped magnetic body is used and magnetized as described above, so that the first magnet 11 is formed on the outside in the radial direction R, and the fourth magnet 15 is formed on the inside in the radial direction R. As a result, an unmagnetized intermediate portion IM2 is formed between the first magnet 11 and the fourth magnet 15 in the radial direction R.

[0096] In the power transmission device 100B according to this embodiment, when the motor 2 is driven to rotate the second gear 32B in the circumferential direction C, the second back yoke 122 and the second magnet 12 fixed to the second gear 32B rotate in the circumferential direction C together with the second gear 32B. Then, a change in the magnetic flux of the second magnetic pole 121 of the second magnet 12 is modulated by the first pole piece 13 and transmitted to the first magnetic pole 111 of the first magnet 11. Therefore, as the second magnet 12 rotates in the circumferential direction C, the first magnet 11 rotates in the circumferential direction C. Then, because the first magnet 11 and the fourth magnet 15 are integrally formed, as the first magnet 11 rotates in the circumferential direction C, the fourth magnet 15 rotates in the circumferential direction C. Then, a change in the magnetic flux of the fourth magnetic pole 151 of the fourth magnet 15 is modulated by the second pole piece 16 and transmitted to the third magnetic pole 141 of the third magnet 14. Therefore, as the fourth magnet 15 rotates in the circumferential direction C, the third magnet 14 also rotates in the circumferential direction C. Since the second shaft 17 is fixed to the third magnet 14, as the third magnet 14 rotates in the circumferential direction C, the second shaft 17 also rotates in the circumferential direction C.

[0097] The magnetic gear device 1B of the power transmission device 100B according to this embodiment has the following configuration: The magnetic gear device 1B includes a first magnet 11 having a plurality of first magnetic poles 111 arranged in the circumferential direction C, a second magnet 12 having a plurality of second magnetic poles 121 arranged in the circumferential direction C, a first pole piece 13 located between the first magnet 11 and the second magnet 12 in the radial direction R and magnetically connecting the first magnet 11 and the second magnet 12, a third magnet 14 having a plurality of third magnetic poles 141 arranged in the circumferential direction C, a fourth magnet 15 having a plurality of fourth magnetic poles 151 arranged in the circumferential direction C, and a second pole piece 16 located between the third magnet 14 and the fourth magnet 15 and magnetically connecting the third magnet 14 and the fourth magnet 15. Furthermore, the first magnet 11 and the fourth magnet 15 are connected in the radial direction R of this magnetic gear device 1B, the fourth magnet 15 rotates together with the first magnet 11, the number of first magnetic poles 111 of the first magnet 11 is greater than the number of second magnetic poles 121 of the second magnet 12, the number of third magnetic poles 141 of the third magnet 14 is greater than the number of fourth magnetic poles 151 of the fourth magnet 15, the first magnet 11 has a plurality of first magnetic poles 111 integrally formed therewith, the third magnet 14 has a plurality of third magnetic poles 141 integrally formed therewith, and at least one of the four first magnets 11 to 15 is ring-shaped. Therefore, the power transmission device 100B according to this embodiment can increase the torque of the second shaft 17 (torque on the output side) more than the torque of the first shaft 22 (torque on the input side). Furthermore, the power transmission device 100B according to this embodiment has the same functions and effects as the power transmission device 100 according to the first embodiment.

[0098] In the power transmission device 100B of this embodiment, the first magnet 11 and the fourth magnet 15 are formed as a single unit, and therefore the number of parts can be reduced, thereby improving workability during assembly, compared to a power transmission device in which the first magnet 11 and the fourth magnet 15 are formed separately.

[0099] In the power transmission device 100B according to this embodiment, the first magnet 11 is disposed inside the second magnet 12 in the radial direction R, and the third magnet 14 is disposed inside the fourth magnet 15 in the radial direction R.

[0100] Although the power transmission device 100B described above has the first magnet 11 and the fourth magnet 15 formed integrally, the power transmission device 100B according to this embodiment is not limited to this. For example, the first magnet 11 and the fourth magnet 15 may be formed separately, and a separate ring-shaped connecting portion may be formed in place of the intermediate portion IM2, and the first magnet 11 and the fourth magnet 15 may be connected in the radial direction R via the connecting portion.

[0101] Furthermore, in the magnetic gear device 1B according to the embodiment described above, two-stage magnetic gear mechanisms 1α and 1β are arranged in the radial direction R. However, the magnetic gear device 1B according to this embodiment is not limited to this. For example, the magnetic gear device 1B can have three or more stages of magnetic gear mechanisms arranged in the radial direction R. Furthermore, a three-stage magnetic gear device can also be configured by combining the magnetic gear device 1B according to the embodiment described above with the magnetic gear devices 1 and 1A.

[0102] Furthermore, in the magnetic gear device 1B according to the embodiment described above, the second magnet 12 is on the input side, the first pole piece 13 is fixed, the second pole piece 16 is fixed, and the third magnet 14 is on the output side. However, the magnetic gear device 1B according to this embodiment is not limited to this. For example, as shown in Table 3, the input side, output side, and fixed locations can be changed as appropriate.

[0103] [First Modification of Second Embodiment] Next, a magnetic gear device 1C according to a first modification of the second embodiment will be described with reference to FIGS. 6-1 and 6-2. FIG. 6-1 is a plan view of a power transmission device 100C including the magnetic gear device 1C according to the first modification of the second embodiment. FIG. 6-2 is a perspective view of the magnetic gear device 1C shown in FIG. 6-1. Note that in the configuration of the power transmission device 100C according to the first modification of the second embodiment, the same components as those of the power transmission devices 100 and 100B described above are assigned the same reference numerals and their description will be omitted. Also, the motor 2 and intermediate transmission mechanism 3B are omitted in FIG. 6-2.

[0104] The power transmission device 100C according to this modification includes a motor 2, an intermediate transmission mechanism 3B, and a magnetic gear device 1C.

[0105] The magnetic gear device 1C includes a first magnetic gear mechanism 1α and a second magnetic gear mechanism 1β. The magnetic gear device 1C is also provided with a second shaft 17. The magnetic gear device 1 is a device in which the first magnetic gear mechanism 1α and the second magnetic gear mechanism 1β are connected in the radial direction R.

[0106] The first magnetic gear mechanism 1α is composed of a first magnet 11, a second magnet 12, and a first pole piece 13.

[0107] In the first magnetic gear mechanism 1α, the first magnet 11 is disposed on the outer side of the second magnet 12 in the radial direction R. The first back yoke 112 is disposed on the outer side of the first magnet 11 in the radial direction R. The first magnet 11 according to this modification is disposed on the input side (drive side) of the second magnet 12.

[0108] In the first magnetic gear mechanism 1α, the second magnet 12 is disposed on the inside of the first magnet 11 in the radial direction R. The second magnet 12 according to this modification does not have a back yoke. Furthermore, the second magnet 12 according to this modification is disposed on the output side (driven side) of the first magnet 11.

[0109] The second magnetic gear mechanism 1β is composed of a third magnet 14, a fourth magnet 15, and a second pole piece 16.

[0110] In the second magnetic gear mechanism 1β, the third magnet 14 is disposed outside the fourth magnet 15 in the radial direction R. The third magnet 14 according to this modification does not have a back yoke. The third magnet 14 according to this modification is disposed on the input side (drive side) of the fourth magnet 15.

[0111] In the second magnetic gear mechanism 1β, the fourth magnet 15 is arranged on the inside of the third magnet 14 in the radial direction R, and the fourth back yoke 152 is arranged on the inside of the fourth magnet 15 in the radial direction R. The fourth back yoke 152 is then connected to the second shaft 17. In other words, the fourth magnet 15 according to this modification is arranged on the output side (driven side) relative to the third magnet 14. In the magnetic gear device 1C according to this embodiment, the first magnet 11, the second magnet 12, the third magnet 14, and the fourth magnet 15 are arranged so as to be rotatable about a common axis 17o.

[0112] Furthermore, in the power transmission device 100C according to this modified example, the second magnet 12 and the third magnet 14 are integrally formed. In other words, in this magnetic gear device 1C, the second magnet 12 and the third magnet 14 are connected in the radial direction R, and the third magnet 14 rotates together with the second magnet 12. To explain the second magnet 12 and the third magnet 14 more specifically, a ring-shaped magnetic body is used and magnetized as described above, so that the second magnet 12 is formed on the outside in the radial direction R, and the third magnet 14 is formed on the inside in the radial direction R. As a result, an unmagnetized intermediate portion IM2 is formed between the second magnet 12 and the third magnet 14 in the radial direction R.

[0113] In the power transmission device 100C according to this modified example, when the motor 2 is driven to rotate the second gear 32B in the circumferential direction C, the first back yoke 112 and the first magnet 11 fixed to the second gear 32B rotate in the circumferential direction C together with the second gear 32B. Then, a change in the magnetic flux of the first magnetic pole 111 of the first magnet 11 is modulated by the first pole piece 13 and transmitted to the second magnetic pole 121 of the second magnet 12. Therefore, as the first magnet 11 rotates in the circumferential direction C, the second magnet 12 also rotates in the circumferential direction C. Then, because the second magnet 12 and the third magnet 14 are integrally formed, as the second magnet 12 rotates in the circumferential direction C, the third magnet 14 also rotates in the circumferential direction C. Then, a change in the magnetic flux of the third magnetic pole 141 of the third magnet 14 is modulated by the second pole piece 16 and transmitted to the fourth magnetic pole 151 of the fourth magnet 15. Therefore, as the third magnet 14 rotates in the circumferential direction C, the fourth magnet 15 also rotates in the circumferential direction C. Since the second shaft 17 is fixed to the fourth magnet 15, as the fourth magnet 15 rotates in the circumferential direction C, the second shaft 17 also rotates in the circumferential direction C.

[0114] The magnetic gear device 1C of the power transmission device 100C according to this modified example has the following configuration: The magnetic gear device 1C includes a ring-shaped first magnet 11 having a plurality of first magnetic poles 111 arranged in the circumferential direction C, a ring-shaped second magnet 12 having a plurality of second magnetic poles 121 arranged in the circumferential direction C, a first pole piece 13 located between the first magnet 11 and the second magnet 12 in the radial direction R and magnetically connecting the first magnet 11 and the second magnet 12, a ring-shaped third magnet 14 having a plurality of third magnetic poles 141 arranged in the circumferential direction C, a ring-shaped fourth magnet 15 having a plurality of fourth magnetic poles 151 arranged in the circumferential direction C, and a second pole piece 16 located between the third magnet 14 and the fourth magnet 15 and magnetically connecting the third magnet 14 and the fourth magnet 15. Furthermore, the second magnet 12 and the third magnet 14 are connected in the radial direction R of the power transmission device 100C according to this modification, the third magnet 14 rotates together with the second magnet 12, the number of first magnetic poles 111 of the first magnet 11 is greater than the number of second magnetic poles 121 of the second magnet 12, the number of third magnetic poles 141 of the third magnet 14 is greater than the number of fourth magnetic poles 151 of the fourth magnet 15, the first magnet 11 is integrally formed with a plurality of first magnetic poles 111, and the third magnet 14 is integrally formed with a plurality of third magnetic poles 141. Therefore, the power transmission device 100C according to this modification can increase the speed of the second shaft 17 (the rotational speed of the output side) more than the speed of the first shaft 22 (the rotational speed of the input side). Furthermore, the power transmission device 100C according to this embodiment achieves the same functions and effects as the power transmission device 100 according to the first embodiment.

[0115] In the power transmission device 100C of this modified example, the second magnet 12 and the third magnet 14 are formed as a single unit, thereby reducing the number of parts and improving workability during assembly compared to a power transmission device in which the second magnet 12 and the third magnet 14 are formed separately.

[0116] In the power transmission device 100C according to this modification, the first magnet 11 is disposed outside the second magnet 12 in the radial direction R, and the third magnet 14 is disposed outside the fourth magnet 15 in the radial direction R.

[0117] While the power transmission device 100C described above has the second magnet 12 and the third magnet 14 formed integrally, the power transmission device 100C according to this modification is not limited to this. For example, the second magnet 12 and the third magnet 14 may be formed separately, and a separate ring-shaped connecting portion may be formed in place of the intermediate portion IM2, connecting the second magnet 12 and the third magnet 14 in the radial direction R via the connecting portion. Furthermore, a three-stage magnetic gear device can be configured by combining the magnetic gear device 1C according to the modification described above with the magnetic gear devices 1 and 1A.

[0118] Furthermore, in the magnetic gear device 1C according to the above-described modified example, the first magnet 11 is on the input side, the first pole piece 13 is fixed, the second pole piece 16 is fixed, and the fourth magnet 15 is on the output side. However, the magnetic gear device 1C according to this modified example is not limited to this. For example, as shown in Table 4, the input side, output side, and fixing points can be changed as appropriate.

[0119] Third Embodiment Next, a power transmission device 100D according to a third embodiment will be described with reference to Figures 7 and 8. Figure 7 is a cross-sectional view of the power transmission device 100D according to the third embodiment. Figure 8 is a front view of an intermediate transmission mechanism 3D included in the power transmission device 100D shown in Figure 7. Note that in the configuration of the power transmission device 100D according to the third embodiment, the same components as those in the power transmission device 100 according to the first embodiment are assigned the same reference numerals and their description will be omitted. Also, Figure 7 shows a portion of the first magnetic gear mechanism 1α in the magnetic gear device 1, with the second magnetic gear mechanism 1β omitted.

[0120] The power transmission device 100D according to this embodiment includes a magnetic gear device 1, a motor 2, and an intermediate transmission mechanism 3D. The power transmission device 100D according to this embodiment is arranged so that the axis 22o of the first shaft 22, which is the input shaft, and the axis 17o of the second shaft 17, which is the output shaft, are coaxial. In other words, the power transmission device 100D according to this embodiment is a device in which the axis 22o of the input shaft and the axis 17o of the output shaft are coaxial.

[0121] The intermediate transmission mechanism 3D shown in this embodiment is a planetary gear mechanism, and includes a sun gear 301, a ring gear 302, a plurality of (three in this embodiment) planetary gears 303, and a planet carrier 304.

[0122] The sun gear 301 is formed, for example, in a cylindrical shape and has teeth on its outer circumferential surface. The teeth of the sun gear 301 mesh with the teeth of the planetary gears 303. The sun gear 301 is fixed to the outer circumferential surface of the first shaft 22 of the motor 2.

[0123] The ring gear 302 is formed in an annular shape and has teeth on its inner circumferential surface. The ring gear 302 is fixed to a frame (not shown). In other words, the intermediate transmission mechanism 3D according to this embodiment is a planetary type in which the ring gear 302 is fixed to the frame, the sun gear 301 is not fixed, and the planet carrier 304 is not fixed.

[0124] Each of the planetary gears 303 is formed, for example, in a cylindrical shape and has teeth formed on its outer circumferential surface and a planetary shaft 303 a. The planetary gears 303 are provided in the intermediate transmission mechanism 3D so as to be rotatable around an axis 303 o of the planetary shaft 303 a. The teeth of the planetary gears 303 mesh with the teeth of the ring gear 302 and the sun gear 301.

[0125] The planetary carrier 304 is coupled to each of the planetary shafts 303 a of the planetary gears 303. The planetary carrier 304 is provided in the intermediate transmission mechanism 3D so as to be rotatable about the axis 22 o in accordance with the revolution of the planetary gears 303. Furthermore, in the intermediate transmission mechanism 3D according to this embodiment, the planetary carrier 304 is coupled to the back yoke 122 of the second magnet 12.

[0126] Next, a description will be given of the power transmission device 100D according to this embodiment when the motor 2 is driven. When the motor 2 is driven in the power transmission device 100D, the sun gear 301 rotates about the axis 22o together with the rotation of the first shaft 22.

[0127] As the sun gear 301 rotates, the multiple planetary gears 303 rotate around the axis 303o of the planetary shafts 303a while meshing with the ring gear 302, and also revolve around the sun gear 301. When the planetary gears 303 revolve, because the planetary shafts 303a are connected to the planetary carrier 304, the planetary carrier 304 rotates around the axis 22o in conjunction with the revolution of the planetary gears 303.

[0128] Furthermore, since the planet carrier 304 is connected to the second back yoke 122 of the second magnet 12, the second magnet 12 rotates about the axis 17o as the planet carrier 304 rotates about the axis 22o. Therefore, similar to the power transmission device 100 according to the first embodiment, the first magnet 11, the third magnet 14, the fourth magnet 15, and the second shaft 17 rotate as the second magnet 12 rotates.

[0129] As described above, in the power transmission device 100D according to this embodiment, the axis 22o of the first shaft 22, which is the input shaft, and the axis 17o of the second shaft 17, which is the output shaft, are arranged so as to be coaxial. Therefore, the power transmission device 100D according to this embodiment can be easily modularized and can improve the degree of freedom in layout. Furthermore, this power transmission device 100D can increase torque in the intermediate transmission mechanism 3D, which is a planetary gear mechanism. Therefore, when this intermediate transmission mechanism 3D is combined with a magnetic gear mechanism that increases torque, torque can be further increased.

[0130] [First Modification of Third Embodiment] Next, a power transmission device 100E according to a first modification of the third embodiment will be described with reference to Fig. 9. Fig. 9 is a cross-sectional view of the power transmission device 100E according to the first modification of the third embodiment. Note that in the configuration of the power transmission device 100E according to the first modification of the third embodiment, the same components as those of the power transmission devices 100, 100A, and 100D described above are designated by the same reference numerals and will not be described again. Fig. 9 also shows a portion of the second magnetic gear mechanism 1β in the magnetic gear device 1A connected to the intermediate transmission mechanism 3G.

[0131] A power transmission device 100E according to this modification includes the second magnetic gear mechanism 1β of the magnetic gear device 1A, a motor 2, and an intermediate transmission mechanism 3E.

[0132] The intermediate transmission mechanism 3E shown in this embodiment is a planetary gear mechanism, and includes a sun gear 301, a ring gear 302, a plurality of planet gears 303, and a planet carrier 304.

[0133] In the intermediate transmission mechanism 3E according to this modified example, the planetary carrier 304 is connected to the second back yoke 122.

[0134] Next, a description will be given of the power transmission device 100E according to this embodiment when the motor 2 is driven. When the motor 2 is driven in the power transmission device 100E, the sun gear 301 rotates about the axis 22o together with the rotation of the first shaft 22.

[0135] As the sun gear 301 rotates, the multiple planetary gears 303 rotate around the axis 303o of the planetary shafts 303a while meshing with the ring gear 302, and also revolve around the sun gear 301. When the planetary gears 303 revolve, because the planetary shafts 303a are connected to the planetary carrier 304, the planetary carrier 304 rotates around the axis 22o in conjunction with the revolution of the planetary gears 303.

[0136] Furthermore, because the planet carrier 304 is connected to the second back yoke 122 of the magnetic gear device 1A, the second back yoke 122 and the second magnet 12 rotate about the axis 17o as the planet carrier 304 rotates about the axis 22o. Therefore, similar to the power transmission device 100A according to the first modification of the first embodiment, the first magnet 11, the third magnet 14, the fourth magnet 15, and the second shaft 17 rotate as the second magnet 12 rotates.

[0137] As described above, in the power transmission device 100E according to this modification, the axis 22o of the first shaft 22, which is the input shaft, and the axis 17o of the second shaft 17, which is the output shaft, are arranged so as to be coaxial. Therefore, the power transmission device 100E according to this embodiment can be easily modularized and can improve the degree of freedom in layout. Furthermore, this power transmission device 100E can increase torque in the intermediate transmission mechanism 3E, which is a planetary gear mechanism. Therefore, when this intermediate transmission mechanism 3E is combined with the magnetic gear mechanism 1α, which can increase torque, torque can be further increased.

[0138] [Second Modification of Third Embodiment] Next, a power transmission device 100F according to a second modification of the third embodiment will be described using Fig. 10. Fig. 10 is a cross-sectional view of the power transmission device 100F according to the second modification of the third embodiment. Note that in the configuration of the power transmission device 100F according to the second modification of the third embodiment, the same components as those of the power transmission devices 100 and 100D described above are assigned the same reference numerals and their description will be omitted. Also, Fig. 10 shows a part of the first magnetic gear mechanism 1α in the magnetic gear device 1, and the second magnetic gear mechanism 1β is omitted.

[0139] A power transmission device 100F according to this modified example includes a magnetic gear device 1, a motor 2, and an intermediate transmission mechanism 3F.

[0140] The intermediate transmission mechanism 3F shown in this embodiment is a planetary gear mechanism. The intermediate transmission mechanism 3F, which is a planetary gear mechanism, includes a sun gear 301, a ring gear 302, a plurality of planet gears 303, and a planet carrier 304.

[0141] In an intermediate transmission mechanism 3F according to this modified example, the planetary carrier 304 is fixed to a frame (not shown), and the ring gear 302 is connected to the back yoke 122 of the second magnet 12. The intermediate transmission mechanism 3F according to this embodiment is a star type in which the planetary carrier 304 is fixed to the frame, the sun gear 301 is not fixed, and the ring gear 302 is not fixed.

[0142] Next, a description will be given of the power transmission device 100F according to this embodiment when the motor 2 is driven. When the motor 2 is driven in the power transmission device 100F, the sun gear 301 rotates about the axis 22o together with the rotation of the first shaft 22.

[0143] The plurality of planetary gears 303 rotate around the axis 303o of the planetary shaft 303a while meshing with the ring gear 302 due to the rotation of the sun gear 301. When the planetary gears 303 revolve, the ring gear 302 rotates around the axis 303o in conjunction with the revolution of the planetary gears 303 because the planet carrier 304 is connected to the frame.

[0144] Furthermore, because the ring gear 302 is connected to the second back yoke 122 of the magnetic gear device 1, the second magnet 12 rotates about the axis 17o as the ring gear 302 rotates about the axis 22o. Therefore, similar to the power transmission device 100 according to the first embodiment, the first magnet 11, the third magnet 14, the fourth magnet 15, and the second shaft 17 rotate as the second magnet 12 rotates.

[0145] As described above, in the power transmission device 100F according to this embodiment, the axis 22o of the first shaft 22, which is the input shaft, and the axis 17o of the second shaft 17, which is the output shaft, are arranged so as to be coaxial. Therefore, the power transmission device 100F according to this embodiment can be easily modularized and can improve the degree of freedom in layout. Furthermore, this power transmission device 100F can also increase torque in the intermediate transmission mechanism 3F, which is a planetary gear mechanism, thereby further increasing torque.

[0146] [Third Modification of Third Embodiment] Next, a power transmission device 100G according to a third modification of the third embodiment will be described with reference to FIGS. 11 and 12. FIG. 11 is a cross-sectional view of the power transmission device 100G according to the third modification of the third embodiment. FIG. 12 is a front view of an intermediate transmission mechanism 3G included in the power transmission device 100G shown in FIG. 11. Note that in the configuration of the power transmission device 100G according to the third modification of the third embodiment, the same components as those in the power transmission device 100 according to the first embodiment and the power transmission device 100D according to the third embodiment are denoted by the same reference numerals and description thereof will be omitted. FIG. 11 also shows a portion of the second magnetic gear mechanism 1β in the magnetic gear device 1A connected to the intermediate transmission mechanism 3G.

[0147] A power transmission device 100G according to this modification includes the second magnetic gear mechanism 1β of the magnetic gear device 1A, a motor 2, and an intermediate transmission mechanism 3G.

[0148] The intermediate transmission mechanism 3G shown in this embodiment is a planetary gear mechanism. The intermediate transmission mechanism 3G, which is a planetary gear mechanism, includes a sun gear 301, a ring gear 302, a plurality of planet gears 303, and a planet carrier 304.

[0149] In the intermediate transmission mechanism 3G according to this modification, the first shaft 22 is connected to a planetary carrier 304. The sun gear 301 is connected to the second shaft 17 via a shaft 305. The ring gear 302 is fixed to a frame (not shown).

[0150] Next, a description will be given of the power transmission device 100G according to this embodiment when the motor 2 is driven. When the motor 2 is driven in the power transmission device 100G, the planet carrier 304 rotates about the axis 22o.

[0151] The planetary gears 303 rotate about the axis 303o of the planetary shafts 303a while meshing with the ring gear 302 due to the rotation of the planet carrier 304, and also revolve around the periphery of the sun gear 301. When the planetary gears 303 revolve, the sun gear 301 rotates about the axis 22o. Because the sun gear 301 according to this modification is connected to the second shaft 17 via the axis 305, the second back yoke 122 rotates about the axis 17o as the sun gear 301 rotates.

[0152] Therefore, as the sun gear 301 rotates, the second magnet 12 rotates, and this rotation causes the first magnet 11, the third magnet 14, and the fourth magnet 15 to rotate.

[0153] As described above, in the power transmission device 100G according to this modification, the axis 22o of the first shaft 22, which is the input shaft, and the axis 17o of the second shaft 17, which is the output shaft, are arranged so as to be coaxial. Therefore, the power transmission device 100G according to this embodiment can be easily modularized and can improve the degree of freedom in layout. Furthermore, this power transmission device 100G can increase the speed in the intermediate transmission mechanism 3G, which is a planetary gear mechanism. Therefore, when the power transmission device 100G is coupled to a magnetic gear mechanism 1α, which increases speed, the speed can be further increased.

[0154] The intermediate transmission mechanisms 3D, 3E, and 3G according to the third embodiment and the modified examples have been described as planetary types in which the ring gear 302 is fixed to the frame, the sun gear 301 is not fixed, and the planet carrier 304 is not fixed, while the intermediate transmission mechanism 3F has been described as a star-type planetary gear mechanism in which the planet carrier 304 is fixed, the sun gear 301 is not fixed, and the ring gear 302 is not fixed. However, the intermediate transmission mechanisms 3D, 3E, 3F, and 3G according to the present embodiment and the modified examples are not limited to these. For example, the intermediate transmission mechanisms can be applied to solar-type planetary gear mechanisms in which the sun gear 301 is fixed, the ring gear 302 is not fixed, and the planet carrier 304 is not fixed.

[0155] 13, a power transmission device 100H according to a fourth embodiment includes a magnetic gear device 1, a motor 2 (not shown), and a transmission mechanism 3H. In the power transmission device 100H according to this embodiment, the motor 2 is connected to an axis 17o of the input shaft, which is disposed orthogonal to the output shaft of the transmission mechanism 3H. In other words, the power transmission device 100H according to this embodiment is an orthogonal-axis device in which the axis 17o of the input shaft and the output shaft of the transmission mechanism 3H are disposed orthogonal to each other.

[0156] The transmission mechanism 3H includes a pinion gear 313 and a rack gear 312. The pinion gear 313 is, for example, cylindrical and has a plurality of teeth. The inner peripheral surface of the pinion gear 313 is fixed to the outer peripheral surface of the second back yoke 122.

[0157] The rack gear 312 extends, for example, perpendicular to the direction in which the axis 17o extends. The rack gear 312 has a plurality of teeth. In the transmission mechanism 3H, the teeth of the rack gear 312 mesh with the teeth of the pinion gear 311.

[0158] The output shaft (not shown) of the motor is fixed to the axis 17o. Therefore, when the motor of this power transmission mechanism 1H is driven, the first magnet 11 is driven, which causes the second magnet 12 to rotate in the circumferential direction C via the first pole piece 13. This causes the pinion gear 313 to rotate in the circumferential direction C together with the second magnet 12 and the second back yoke 122. This causes the rack gear 312, which meshes with the teeth of the pinion gear 313, to move in a direction perpendicular to the axial direction A and the radial direction R. The moving direction of the rack gear 312 at this time is the output axial direction of the power transmission mechanism 1H. In other words, the rack gear 312 is the output shaft of the transmission mechanism 3H. In this embodiment, the magnetic gear device 1 serves as an intermediate transmission mechanism.

[0159] Fifth Embodiment Next, a power transmission device 100I according to a fifth embodiment will be described with reference to Fig. 14. Fig. 14 is a cross-sectional view of the power transmission device 100I according to the fifth embodiment. Note that in the configuration of the power transmission device 100I according to the fifth embodiment, the same components as those in the power transmission device 100 according to the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0160] The power transmission device 100I according to this embodiment includes a magnetic gear device 1, a motor 2, and an intermediate transmission mechanism 3I. The power transmission device 100I according to this embodiment is arranged so that the axis 22o of the first shaft 22, which is the input shaft, and the axis 17o of the second shaft 17, which is the output shaft, are perpendicular to each other. In other words, the power transmission device 100I according to this embodiment is an orthogonal-axis device in which the axis 22o of the input shaft and the axis 17o of the output shaft are perpendicular to each other.

[0161] The intermediate transmission mechanism 3I includes a first bevel gear 321 and a second bevel gear 322. The first bevel gear 321 is fixed to the first shaft 22 and has a plurality of teeth.

[0162] The second bevel gear 322 has a plurality of teeth. The second bevel gear 322 is fixed to the outer peripheral surface of the second back yoke 122 of the second magnet 12 in the radial direction R. In the intermediate transmission mechanism 3I, the teeth of the first bevel gear 321 and the teeth of the second bevel gear 322 mesh with each other.

[0163] [Sixth Embodiment] Next, a power transmission device 100J according to a sixth embodiment will be described with reference to Figure 15. Figure 15 is a plan view of the power transmission device 100J according to the sixth embodiment. Note that in the configuration of the power transmission device 100J according to the sixth embodiment, the same components as those in the power transmission device 100 according to the first embodiment and those in the power transmission device 100B according to the second embodiment will be assigned the same reference numerals and descriptions thereof will be omitted.

[0164] The power transmission device 100J according to this embodiment includes a magnetic gear device 1, a motor 2, and an intermediate transmission mechanism 3B. The power transmission device 100J according to this embodiment is arranged so that the axis 22o of the first shaft 22, which is the input shaft, and the axis 17o of the second shaft 17, which is the output shaft, are parallel to each other. In other words, the power transmission device 100J according to this embodiment is a parallel-axis device in which the axis 22o of the input shaft and the axis 17o of the output shaft are parallel to each other.

[0165] As described above, in the power transmission device 100J according to this embodiment, the axis 22o of the first shaft 22, which is the input shaft, and the axis 17o of the second shaft 17, which is the output shaft, are arranged to be parallel to each other. Therefore, the power transmission device 100J according to this embodiment can be easily modularized and can improve the degree of freedom in layout.

[0166] The above has been a description of the embodiments and modifications of the magnetic gear devices 1, 1A, 1B, and 1C according to the present invention, and the embodiments and modifications of the power transmission devices 100, 100A, 100B, 100C, 100D, 100E, 100F, 100G, 100H, 100I, and 100J. However, the present invention is not limited to the embodiments and modifications, and various modifications are possible without departing from the spirit of the present invention. The present invention also includes configurations in which the components of the above-described embodiments and modifications are appropriately combined. Such modifications without departing from the spirit of the present invention are also included within the technical scope of the present invention, as will be apparent to those skilled in the art from the claims.

[0167] 1, 1A, 1B, 1C Magnetic gear device, 11 First magnet, 111 First magnetic pole, 12 Second magnet, 121 Second magnetic pole, 13 First pole piece, 14 Third magnet, 141 Third magnetic pole, 15 Fourth magnet, 151 Fourth magnetic pole, 16 Second pole piece, 100, 100A, 100B, 100C, 100D, 100E, 100F, 100G, 100H, 100I, 100J Power transmission device, A Axial direction, C Circumferential direction, R Radial direction

Claims

1. A magnetic gear device comprising: a first magnet having a plurality of first magnetic poles arranged in the circumferential direction; a second magnet having a plurality of second magnetic poles arranged in the circumferential direction; a first pole piece located between the first magnet and the second magnet in the radial direction and magnetically connecting the first magnet and the second magnet; a third magnet having a plurality of third magnetic poles arranged in the circumferential direction; a fourth magnet having a plurality of fourth magnetic poles arranged in the circumferential direction; and a second pole piece located between the third magnet and the fourth magnet in the radial direction and magnetically connecting the third magnet and the fourth magnet; wherein the first magnet and the fourth magnet are connected in the axial direction; the fourth magnet rotates together with the first magnet; the number of first magnetic poles of the first magnet is greater than the number of second magnetic poles of the second magnet; the number of third magnetic poles of the third magnet is greater than the number of fourth magnetic poles of the fourth magnet; and at least one of the first magnet to the fourth magnet is ring-shaped.

2. A magnetic gear device comprising: a first magnet having a plurality of first magnetic poles arranged in the circumferential direction; a second magnet having a plurality of second magnetic poles arranged in the circumferential direction; a first pole piece located between the first magnet and the second magnet in the radial direction and magnetically connecting the first magnet and the second magnet; a third magnet having a plurality of third magnetic poles arranged in the circumferential direction; a fourth magnet having a plurality of fourth magnetic poles arranged in the circumferential direction; and a second pole piece located between the third magnet and the fourth magnet and magnetically connecting the third magnet and the fourth magnet; wherein the first magnet and the fourth magnet are connected in the radial direction; the fourth magnet rotates together with the first magnet; the number of first magnetic poles of the first magnet is greater than the number of second magnetic poles of the second magnet; the number of third magnetic poles of the third magnet is greater than the number of fourth magnetic poles of the fourth magnet; and at least one of the first magnet to the fourth magnet is ring-shaped.

3. A magnetic gear device according to claim 1, wherein the first magnet is disposed inside the second magnet in the radial direction, and the third magnet is disposed outside the fourth magnet in the radial direction.

4. The magnetic gear device according to claim 1, wherein the first magnet is disposed radially outward of the second magnet, and the third magnet is disposed radially inward of the fourth magnet.

5. A magnetic gear device according to claim 2, wherein the first magnet is disposed inside the second magnet in the radial direction, and the third magnet is disposed inside the fourth magnet in the radial direction.

6. A magnetic gear device according to claim 2, wherein the first magnet is disposed radially outward of the second magnet, and the third magnet is disposed radially outward of the fourth magnet.

7. A magnetic gear device according to any one of claims 1 to 6, wherein the first magnet has the plurality of first magnetic poles integrally formed therewith, and the third magnet has the plurality of third magnetic poles integrally formed therewith.

8. The magnetic gear device according to claim 7, wherein the first magnet and the fourth magnet are integrally formed.

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