Power transmission device

Abstract

A power transmission device (100) is provided with an input-side device (2) and a magnetic gear device (1) to which the driving force of the input-side device (2) is directly or indirectly transmitted. The magnetic gear device (1) is a harmonic-type magnetic gear device and at least includes: 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); pole pieces (13) positioned between the first magnet (11) and the second magnet (12) and magnetically connecting the first magnet (11) and the second magnet (12); a first sensor (SE1) for detecting, at a detection point, a change in magnetic flux density of a magnetic field created by the magnetic poles of either the first magnet (11) or the second magnet (12); and a calculation unit (41) for outputting information pertaining to the magnetic gear device (1) on the basis of the detection result of the first sensor (SE1).

Description

power transmission device

[0001] The present invention relates to a power transmission device.

[0002] Conventionally, a magnetic gear device has been known that includes a first magnetic gear having a plurality of magnetic poles arranged in a circumferential direction, and a second magnetic gear having a plurality of magnetic poles arranged in a circumferential direction, with a portion of the outer surface of the first magnetic gear facing a portion of the outer surface of the second magnetic gear (see, for example, Patent Document 1).

[0003] International Publication No. 2003 / 036237

[0004] However, the technology described in Patent Document 1 has room for improvement in terms of increasing torque density.

[0005] The present invention has been made in view of the above, and has as its object to provide a power transmission device that can increase torque density.

[0006] In order to solve the above-mentioned problems and achieve the object, the power transmission device of the present invention comprises an input side device and a magnetic gear device to which the driving force of the input side device is directly or indirectly transmitted, and the magnetic gear device is a harmonic type magnetic gear device and comprises at least 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 pole piece located between the first magnet and the second magnet and magnetically connecting the first magnet and the second magnet, a first sensor that detects changes in magnetic flux density at a detection point of the magnetic field created by the magnetic poles of either the first magnet or the second magnet, and a calculation unit that outputs information about the magnetic gear device based on the detection result of the first sensor.

[0007] According to one aspect of the power transmission device of the present invention, torque density can be increased.

[0008] FIG. 1-1 is a plan view of a power transmission device including a magnetic gear device according to the first embodiment. FIG. 1-2 is a graph showing the relationship between the rotation angle of the second magnet and the magnetic flux density at the positions where the first sensor and the second sensor are disposed, respectively. FIG. 1-3 is a graph showing the relationship between the rotation angle of the second magnet and the voltage for the output of the first sensor and the output of the second sensor, respectively. FIG. 1-4 is a graph showing the relationship between the rotation angle of the second magnet and the magnetic flux density at the positions where the first sensor is disposed, respectively. FIG. 1-5 is a graph showing the relationship between the rotation angle of the first magnet and the magnetic flux density at the positions where the second sensor is disposed, respectively. FIG. 1-6 is a graph showing the relationship between torque and phase difference. FIG. 1-7 is a graph showing the relationship between the magnetic flux density and the phase angle of the first magnet and the second magnet when the torque input to the magnetic gear device exceeds a first threshold value. FIG. 1-8 is a graph showing the relationship between the magnetic flux density and the phase angle of the first magnet and the second magnet when the torque input to the magnetic gear device is increased compared to the state shown in FIG. 1-7. FIG. 2-1 is a cross-sectional view taken along the arrows A-A in FIG. 1. FIG. 2-2 is a perspective view showing an electronic lock, which is an example of a power transmission device. FIG. 3 is a perspective view of the magnetic gear device shown in FIG. 1. FIG. 4 is a perspective view of a magnetic gear device according to a first modified example of the first embodiment. FIG. 5 is a perspective view of a magnetic gear device according to a second modified example of the first embodiment. FIG. 6 is a cross-sectional view of a power transmission device including a magnetic gear device according to the second embodiment. FIG. 7-1 is a perspective view of the magnetic gear device shown in FIG. 6. FIG. 7-2 is a plan view of a second magnetic gear mechanism included in the magnetic gear device shown in FIG. 6. FIG. 8 is a cross-sectional view of a power transmission device including a magnetic gear device according to the first modified example of the second embodiment. FIG. 9-1 is a perspective view of the magnetic gear device shown in FIG. 8. FIG. 9-2 is a cross-sectional view showing the other axial side of the magnetic gear device shown in FIG. 8. Fig. 10-1 is a plan view of a power transmission device including a magnetic gear device according to a third embodiment. Fig. 10-2 is a perspective view of the magnetic gear device shown in Fig. 10-1. Fig. 11-1 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. 11-2 is a perspective view of the magnetic gear device shown in Fig. 11-1.FIG. 12 is a plan view of a power transmission device according to a fourth embodiment. FIG. 13 is a cross-sectional view of a power transmission device according to a fifth embodiment. FIG. 14 is a cross-sectional view of a power transmission device according to a sixth embodiment. FIG. 15 is a cross-sectional view of a power transmission device according to a seventh embodiment. FIG. 16 is a front view of an intermediate transmission mechanism included in the power transmission device shown in FIG. 15. FIG. 17 is a cross-sectional view of a power transmission device according to a first modified example of the seventh embodiment. FIG. 18 is a cross-sectional view of a power transmission device according to a second modified example of the seventh embodiment. FIG. 19 is a cross-sectional view of a power transmission device according to a third modified example of the seventh embodiment. FIG. 20 is a front view of an intermediate transmission mechanism included in the power transmission device shown in FIG. 19. FIG. 21 is a plan view of a power transmission device according to an eighth embodiment. FIG. 22 is a plan view of a power transmission device according to a first modified example of the eighth embodiment. FIG. 23 is a plan view of a power transmission device according to a second modified example of the eighth embodiment. FIG. 24 is a plan view of a power transmission device according to a third modified example of the eighth embodiment. FIG. 25 is a plan view of a power transmission device according to a fourth modified example of the eighth embodiment. FIG. 26 is a plan view of a power transmission device according to a fifth modified example of the eighth embodiment.

[0009] Hereinafter, a power transmission device according to an embodiment will be described in detail 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. 1-1 is a plan view of a power transmission device 100 including a magnetic gear device 1 according to a first embodiment. Fig. 2-1 is a cross-sectional view taken along the line A-A in Fig. 1. Fig. 2-2 is a perspective view showing an electronic lock, which is an example of the power transmission device 100. Fig. 3 is a perspective view of the magnetic gear device 1 shown in Fig. 1. For ease of explanation, the back yokes 112, 122 are omitted from Fig. 2, and the motor 2, intermediate transmission mechanism 3, and second shaft 17 are omitted from Fig. 3.

[0011] In describing the power transmission device 100 including the magnetic gear device 1 shown in Figures 1-1, 2-1, 2-2, and 3 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 and the second magnet 12 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 axes 2o and 17o, and perpendicular to the circumferential direction C will be referred to as the radial direction R.

[0012] A power transmission device (transmission) 100 according to this embodiment shown in FIGS. 1-1, 2-1, 2-2, and 3 transmits torque from a first shaft 22, which is an input shaft, to a second shaft 17, which is an output shaft. In the power transmission device 100 according to this embodiment, the axis 2o 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 disposed in a twisted position. In other words, the power transmission device 100 according to this embodiment is a device with skewed shafts, in which the axis 2o of the input shaft and the axis 17o of the output shaft are disposed in a twisted position. The power transmission device 100 includes, for example, a magnetic gear device 1, a motor 2, and an intermediate transmission mechanism 3.

[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 that is an input shaft. The motor 2 is an electric motor that converts electrical energy supplied from a power source into mechanical energy that is the rotation of the first shaft 22. The motor 2 is an example of an input device in the power transmission device 100 according to this embodiment.

[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 2o and is provided rotatably about the axis 2o relative to the frame and the main body 21. The axis 2o of the first shaft 22 is disposed in a twisted position with respect to the axis 17o of the second shaft 17. The first shaft 22 also extends along a first direction D.

[0017] The intermediate transmission mechanism 3 transmits the driving force from the motor 2 to the magnetic gear device 1. The intermediate transmission mechanism 3 includes, for example, a first gear 31 and a second gear 32.

[0018] The first gear 31 is, for example, a worm. The first gear 31 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.

[0019] The second gear 32 is, for example, a worm wheel formed to rotate in the circumferential direction C together with the second magnet 12 in the magnetic gear device 1. The second gear 32 meshes with the first gear 31, which is a worm. The intermediate transmission mechanism 3 according to this embodiment is constituted by the mechanical first gear 31 and second gear 32.

[0020] When the intermediate transmission mechanism 3 and motor 2 having the above configuration are driven, the first shaft 22 rotates about the axis 2o, and in response to this rotation, the first gear 31 rotates about the axis 2o. Then, in response to the rotation of the first gear 31, the second gear 32 meshing with the first gear 31 rotates together with the second magnet 12 in the circumferential direction C about the axis 17o.

[0021] The magnetic gear device 1 includes a first magnet 11, a second magnet 12, and a first pole piece 13. The magnetic gear device 1 is also provided with a second shaft 17. The magnetic gear device 1 according to this embodiment is a so-called flux modulation type magnetic gear (harmonic type magnetic gear device) in that, when the second magnet 12 connected to the input side (drive side) rotates 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 output side (driven side), causing the first magnet 11 to rotate around the axis 17o. Furthermore, in the magnetic gear device 1 according to this embodiment, the first magnet 11, the second magnet 12, and the first pole piece 13 are formed separately.

[0022] The first magnet 11 is provided to be rotatable in the circumferential direction C around 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 to be rotatable around 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 pole piece 13 in a vacuum state or when a fluid such as air, water, or oil is present.

[0023] 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 body as described below. The first magnet 11 has, for example, 52 first magnetic poles 111, so the number of pole pairs of the first magnet 11 is 26.

[0024] 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.

[0025] Here, the first magnet 11 is formed in a ring shape as shown in Figures 1-1 and 3, and has a downward side surface 11a and an upward side surface 11b as shown in Figure 2-1. 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.

[0026] 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.

[0027] 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.

[0028] 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 an increase in the size and cost of the magnetization device.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).

[0029] 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.

[0030] The second magnet 12 is rotatable 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 rotatable 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. Since the second magnet 12 has, for example, six second magnetic poles 121, the number of pole pairs of the second magnet 12 is three. Furthermore, a second back yoke 122 is provided on the second magnet 12, for example, on the outer side in the radial direction R. 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 pole piece 13 to rotate when in a vacuum state or when a fluid such as air, water, or oil is present.

[0031] The first pole piece 13 is composed of a plurality of (e.g., 29) 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).

[0032] 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 13M of first modulation pieces 131 of the first pole piece 13 is 29. 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 first pole piece 13 is fixed, the reduction ratio X1 can be calculated as follows: X1 = 11M ÷ 12M = 26 ÷ 3 = 8.67

[0033] Alternatively, when the second magnet 12 is the input, the first 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

[0034] 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 rotatable about the axis 17o relative to the frame. The second shaft 17 is fixed to the inner circumferential surface of the first back yoke 112 of the first magnet 11 in the radial direction R and rotates in the circumferential direction C together with the first magnet 11. The magnetic gear device 1 outputs torque to the outside when the second shaft 17 rotates about the axis 17o in the circumferential direction C. The power transmission device 100 according to this embodiment is applied to, for example, an electronic lock, as shown in FIG. 2-2 . In an electronic lock, for example, one end of the second shaft 17 of the magnetic gear device 1 is connected to a rotating shaft of the lock, and the lock is locked or unlocked by rotating the rotating shaft of the lock through the operation of the motor 2. The other end 17a of the second shaft 17 is attached to the frame so as to be exposed to the outside, and the second shaft 17 can also be rotated in the circumferential direction C by manual operation by an operator.

[0035] In the power transmission device 100 according to this embodiment, when the motor 2 is driven to rotate the second gear 32 in the circumferential direction C, the second back yoke 122 and the second magnet 12 fixed to the second gear 32 rotate in the circumferential direction C together with the second gear 32. The change in magnetic flux of the second magnetic pole 121 in 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 connected to the driven side. In this case, in the magnetic gear device 1 according to this embodiment, the number of first magnetic poles 111 of the first magnet 11 arranged inside 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, although the rotation speed in the circumferential direction C decreases, the torque can be increased. Furthermore, in the magnetic gear device 1 according to this embodiment, the first magnet 11 has a ring shape in which multiple first magnetic poles 111 are arranged in the circumferential direction C and are integrally formed. Therefore, the magnetic gear device 1 of this embodiment can increase torque because the pitch of the multiple first magnetic poles 111 in the circumferential direction C can be narrowed compared to, for example, a magnetic gear device having a ring-shaped first magnet formed by connecting multiple individually formed magnets (for example, the device described in JP 2022-150601 A).

[0036] 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, 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 magnetic gear device 1, 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 set 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 magnetic gear device 1, the magnetic gear device 1 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 magnetic gear device 1 according to this embodiment can protect the motor 2 by separating the drive side from the driven side during an overload. Alternatively, if unintended torque is generated by the motor 2, the magnetic gear device 1 functions as a torque limiter, separating the drive side from the driven side to protect the load side. Furthermore, if the magnetic gear device 1 is used in an electric opening and closing mechanism for a home appliance, it can cut off torque from the drive side when a member on the load side comes into contact with the human body, and therefore can also function as a safety device that minimizes the impact on the human body.

[0037] Next, the control unit 44 will be described with reference to Figures 1 to 1-8. The control unit 4 comprehensively controls each unit of the power transmission device 100, such as driving and stopping the motor 2. The control unit 4 also includes a calculation unit 41, which is electrically connected to each of the sensors SE1, SE21, and SE22.

[0038] Each of the sensors SE1, SE21, and SE22 is, for example, a Hall sensor. The Hall sensor is a non-contact magnetic sensor that uses the Hall effect to convert magnetic flux density into an electric signal and output the electric signal.

[0039] The sensor SE1 is fixed to the frame so as to be able to detect, for example, a change in the magnetic flux density of the second magnet 12. The sensor SE1 is an example of the first sensor SE1 in the power transmission device 100 according to this embodiment.

[0040] The sensor SE21 is fixed to the frame, for example, at a position different from the sensor SE1 in the circumferential direction C so as to be able to detect changes in the magnetic flux density of the second magnet 12. The sensor SE21 is an example of the second sensor SE2 in the power transmission device 100 according to this embodiment. In the power transmission device 100 according to this embodiment, the sensors SE1 and SE21 are arranged such that the angle with respect to the circumferential direction C is 30 degrees, for example.

[0041] The sensor SE22 is fixed to the frame, for example, at a position different from the position of the sensor SE1 in the radial direction R, so as to be able to detect changes in the magnetic flux density of the first magnet 11. The sensor SE22 is an example of the second sensor SE2 in the power transmission device 100 according to this embodiment.

[0042] The calculation unit 41 is electrically connected to each of the sensors SE1, SE21, and SE22. The calculation unit 41 outputs information about the magnetic gear device 1 based on the detection results of the first sensor SE1 and the second sensor SE2.

[0043] To explain the calculation unit 41 in more detail, the calculation unit 41 outputs the rotational angle position of the target ring-shaped magnet (in this embodiment, the second magnet 12) based on the detection results of the sensors SE1 and SE21. The output of the rotational angle position by the calculation unit 41 will be explained below.

[0044] When the second magnet 12 rotates in the circumferential direction C, as shown in Fig. 1-2, the magnetic flux density changes in accordance with the change in the rotation angle due to the second magnetic pole 121 of the second magnet 12. Fig. 1-2 is a graph showing the relationship between the rotation angle of the second magnet 12 and the magnetic flux density at the position where the sensor SE1 is disposed and at the position where the sensor SE21 is disposed. In Fig. 1-2, the solid line represents the magnetic flux density at the position where the sensor SE1 is disposed, and the dashed line represents the magnetic flux density at the position where the sensor SE21 is disposed.

[0045] At this time, the outputs of sensors SE1 and SE22, which convert the magnetic flux density into an electric signal, are shown in Figure 1-3. Figure 1-3 is a graph showing the relationship between the rotation angle of the second magnet 12 and the voltage for the output of sensor SE1 and the output of sensor SE21. In Figure 1-3, the solid line indicates the output of sensor SE1, and the dashed line indicates the output of sensor SE21. The magnetic flux density of the second magnetic pole 121 of the second magnet 12 is converted into a square wave by sensors SE1 and SE21.

[0046] For example, if a positive peak is detected by sensor SE1 and then a positive peak is detected by sensor SE21, the calculation unit 41 determines that the second magnet 12 has rotated 30 degrees in the circumferential direction C. Therefore, the calculation unit 41 outputs the rotational angle position of the second magnet 12 based on the detection results of sensor SE1 and sensor SE21.

[0047] In the above-described embodiment, the power transmission device 100 is described as being provided with sensors SE1 and SE21 that detect the magnetic flux density of the second magnet 12. However, the power transmission device 100 according to this embodiment is not limited to this. For example, two sensors that detect the magnetic flux density of the first magnet 11 may be provided. Furthermore, the number of sensors SE1 and SE21 that detect the magnetic flux density of the second magnet 12 is not limited to two, and may be three or more.

[0048] Furthermore, the calculation unit 41 outputs information relating to the torque in the magnetic gear device 1 based on the detection results of the sensors SE1 and SE22. The output of information relating to the torque in the magnetic gear device 1 by the calculation unit 41 will be described below.

[0049] When the second magnet 12 rotates in the circumferential direction C, as shown in Fig. 1-4, the magnetic flux density changes in accordance with the change in the rotation angle due to the second magnetic pole 121 of the second magnet 12. Fig. 1-4 is a graph showing the relationship between the rotation angle of the second magnet 12 and the magnetic flux density at the position where the sensor SE1 is disposed.

[0050] Furthermore, when the first magnet 11 rotates in the circumferential direction C, as shown in Fig. 1-5, the magnetic flux density changes in accordance with the change in the rotation angle due to the first magnetic pole 111 of the first magnet 11. Fig. 1-5 is a graph showing the relationship between the rotation angle of the first magnet 11 and the magnetic flux density at the position where the sensor SE22 is disposed.

[0051] In the magnetic gear device 1 according to this embodiment, the first magnet 11 has 56 poles, and the second magnet 12 has 6 poles. Furthermore, the first magnet 11 rotates in the circumferential direction C in response to the rotation of the second magnet 12 of the magnetic gear device 1 in the circumferential direction C.

[0052] In the magnetic gear device 1, when torque is applied by a load to either the first magnet 11 side or the second magnet 12 side, a phase difference ΔT1 occurs between the magnetic flux density waveform of the second magnet 12 and the magnetic flux density waveform of the first magnet 11, as shown in Figure 1-7. Figure 1-7 is a graph showing the relationship between the magnetic flux density and the phase angle of the first magnet 11 and the second magnet 12.

[0053] Furthermore, when the torque applied increases compared to the case shown in Fig. 1-7, the phase difference ΔT2 generated between the waveform of the magnetic flux density of the second magnet 12 and the waveform of the magnetic flux density of the first magnet 11 becomes larger than ΔT1, as shown in Fig. 1-8. Fig. 1-7 is a graph showing the relationship between the magnetic flux density and the phase angle of the first magnet 11 and the second magnet 12 when the torque input to the magnetic gear device 1 increases compared to the state shown in Fig. 1-6.

[0054] The torque applied to the magnetic gear device 1 and the resulting phase difference have a relationship as shown in Figure 1-6, depending on the gear specifications. Therefore, from Figure 1-6, it is possible to calculate the torque from the phase difference occurring in the magnetic gear device 1.

[0055] The calculation unit 41 in this embodiment outputs the magnitude of the torque applied to the magnetic gear device 1 based on the magnitude of the phase difference between the detection result of sensor SE1, which converts the magnetic flux density into a rectangular shape, and the detection result of sensor SE22, which converts the magnetic flux density into a rectangular shape.

[0056] As described above, the power transmission device 100 according to this embodiment includes a first sensor SE1 that detects changes in magnetic flux density at a detection point of the magnetic field created by the magnetic poles 111, 121 of either the first magnet 11 or the second magnet 12, and a calculation unit 41 that outputs information about the magnetic gear device based on the detection result of the first sensor SE1.

[0057] The power transmission device 100 according to this embodiment includes a sensor SE21 (second sensor SE2) that is located at a different position in the circumferential direction C from the first sensor SE11 and detects changes in magnetic flux density at a detection point of the magnetic field created by the other magnetic poles 111, 121 of the first magnet 11 and the second magnet 12, and the calculation unit 41 outputs the rotational angle position of the target ring-shaped magnets 11, 12 based on the detection results of the first sensor SE1 and the second sensor SE2. In other words, the power transmission device 100 according to this embodiment has the function of a rotary encoder.

[0058] The power transmission device 100 according to this embodiment includes a sensor SE22 (second sensor SE2) that detects changes in magnetic flux density at a detection point of the magnetic field created by the other magnetic poles 111, 121 of the first magnet 11 and the second magnet 12. In other words, the power transmission device 100 according to this embodiment has the function of a torque meter.

[0059] The magnetic gear device 1 according to this embodiment is a harmonic type and includes a motor 2 as an input device and a magnetic gear device 1 to which the driving force of the motor 2 is indirectly transmitted. More specifically, this magnetic gear device 1 is a harmonic type magnetic gear device in which one of a ring-shaped first magnet 11 and a ring-shaped second magnet 12 is arranged on the outside in the radial direction R and the other is arranged on the inside in the radial direction R, and first magnetic poles 111 of the multiple first magnets 11 are magnetically coupled to second magnetic poles 121 of the multiple second magnets 12 in the radial direction R via a first pole piece 13 therebetween. Therefore, compared to a magnetic gear device (e.g., JP 2011-196451 A) in which the first magnet and the second magnet are arranged so that a portion of the outer peripheral surface of the ring-shaped first magnet overlaps a portion of the outer peripheral surface of the ring-shaped second magnet in the axial direction, the magnetic gear device 1 of this embodiment can magnetically connect the first magnetic pole 111 and the second magnetic pole 121 around the entire axis, thereby increasing the torque density and increasing the torque.

[0060] In addition, the magnetic gear device 1 according to this embodiment includes a ring-shaped first magnet 11 in which a plurality of first magnetic poles 111 are arranged in the circumferential direction C and in which the plurality of first magnetic poles 111 are integrally formed, a ring-shaped second magnet 12 in which a plurality of second magnetic poles 121 are arranged in the circumferential direction C, and a first pole piece 13 located between the first magnet 11 and the second magnet 12 and magnetically connecting the first magnet 11 and the second magnet 12.

[0061] Furthermore, in the magnetic gear device 1 according to this embodiment, the first magnet 11 has multiple first magnetic poles 111 integrally formed. This allows for a smaller and lighter magnetic gear device than one including a first magnet formed by connecting individually formed magnets in the circumferential direction C. Furthermore, since the magnetic gear device 1 includes the first magnet 11 having the above-described configuration, the number of parts can be reduced, the shape of the back yoke 112 and / or the frame can be simplified, and a cover to prevent the first magnetic poles 111 from falling off is not required. Furthermore, since the first magnet 11 has a narrow pitch between the multiple first magnetic poles 111 in the circumferential direction C, torque ripple can be reduced. Furthermore, in the magnetic gear device 1 according to this embodiment, 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. This allows for a greater torque (output torque) of the second shaft 17 connected to the first magnet 11 of the magnetic gear than the torque (input torque) of the first shaft 22 of the motor 2. 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, and the first pole piece 13 and the second magnet 12 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, because the magnetic gear device 1 does not generate dust during use and does not require the use of lubricating oil, it does not require maintenance.

[0062] 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.

[0063] Furthermore, since the intermediate transmission mechanism 3 according to this embodiment is composed of the first gear 31, which is a worm, and the second gear 32, which is a worm wheel, it is possible to reduce the noise generated when the motor 2 is driven.

[0064] In the magnetic gear device 1 according to this embodiment, the first magnet 11 has a plurality of first magnetic poles 111 integrally formed into a ring shape, and the second magnet has a plurality of second magnetic poles 121 integrally formed into a ring shape. This allows for a smaller and lighter magnetic gear device compared to a magnetic gear device having a first magnet and a second magnet formed by connecting individually formed magnets in the circumferential direction C.

[0065] When the power transmission device 100 according to this embodiment is used in an electronic lock as shown in Fig. 2-2, it can electrically lock or unlock the door by operating the motor 2 via the magnetic gear device 1. On the other hand, when a person manually operates the knob attached to the second shaft 17a of the electronic lock, the magnetic gear device 1 functions as a clutch, making it possible to directly operate the lock opening / closing shaft, thereby allowing manual locking or unlocking.

[0066] In the magnetic gear device 1 according to this embodiment, the first pole piece 13 is located between the first magnet 11 and the second magnet 12 in the radial direction R.

[0067] 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 magnets 11 can be arranged even at a narrow pitch inside in the radial direction R.

[0068] In the magnetic gear device 1 according to the embodiment described above, the first pole piece 13 is fixed, the first magnet 11 arranged on the inside in the radial direction R is non-fixed and rotates together with the second shaft 17, and the second magnet 12 arranged on the outside in the radial direction R is non-fixed and rotates together with the second gear 32. However, the magnetic gear device 1 according to this embodiment is not limited to this. The fixed and non-fixed parts may be changed as appropriate.

[0069] In the magnetic gear device 1 according to the embodiment described above, the first magnet 11 has been described as having 52 (26 pole pairs) first magnetic poles 111. 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.

[0070] Furthermore, in the magnetic gear device 1 according to the above embodiment, the second magnet 12 has been described as having six (three pole pairs) second magnetic poles 121. However, the number of second magnetic poles 121 of the second magnet 12 according to this embodiment is not limited to this and can be set to any number.

[0071] 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 29 first modulation pieces 131. However, the number of first modulation pieces 131 constituting the first pole piece 13 according to the present 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 number of modulation pieces 131 of the first pole piece 13 are determined, the number of the remaining one is set appropriately depending on the numbers of the other two.

[0072] Furthermore, in the power transmission device 100 according to the above embodiment, the intermediate transmission mechanism 3 has been described as including the first gear 31, which is a worm, and the second gear 32, which is a worm wheel. However, the intermediate transmission mechanism 3 according to the present embodiment is not limited to this. For example, the intermediate transmission mechanism 3 may include a first gear, which is a screw gear, and a second gear 32, which meshes with the first gear and is also a screw gear. Of course, the intermediate transmission mechanism 3 is not limited to this, and may be configured with a plurality of meshing gears, or may be configured using other gears. For example, a helical gear or the like may be used as the other gear.

[0073] 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. Similarly, the first magnet 11 can also be formed by joining a plurality of magnets each having two first magnetic poles 111.

[0074] 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 first magnet 11 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 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 first pole piece 13 is fixed, the speed increase ratio X3 can be calculated as follows: X3 = 11M ÷ 12M = 26 ÷ 3 = 8.67

[0075] Alternatively, when the first 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

[0076] Furthermore, for example, in the magnetic gear device 1 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 first pole piece 13 is fixed, the reduction ratio X5 can be calculated as follows: X5 = 11M ÷ 12M = 26 ÷ 3 = 8.67

[0077] Alternatively, when the first 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

[0078] Furthermore, the power transmission device 100 according to the above embodiment has been described as having an intermediate transmission mechanism 3 provided between the motor 2 and the magnetic gear device 1. In other words, the power transmission device 100 according to this embodiment is a device in which the driving force of the motor 2 is indirectly transmitted to the magnetic gear device 1 (i.e., via the intermediate transmission mechanism 3). However, the power transmission device 100 according to this embodiment is not limited to this, and the intermediate transmission mechanism 3 does not have to be provided. In other words, the magnetic gear device 1 according to this embodiment is a device to which power is input directly or indirectly from the motor 2, which is the driving source. Furthermore, the driving source may be something other than the motor 2.

[0079] [First Modification of First Embodiment] Next, a magnetic gear device 1A according to a first modification of the first embodiment will be described using Fig. 4. Fig. 4 is a plan view of the magnetic gear device 1A according to the first modification of the first embodiment. 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 given the same reference numerals and description thereof will be omitted. Furthermore, although not shown, a motor 2 and an intermediate transmission mechanism 3 similar to those in the power transmission device 100 according to the first embodiment are arranged on the radially outer side R of the magnetic gear device 1A.

[0080] The magnetic gear device 1A according to this embodiment has a first magnet 11, a second magnet 12, and a first pole piece 13.

[0081] In the magnetic gear device 1A, the first magnet 11 is disposed outside the second magnet 12 in the radial direction R, and the first back yoke 112 is fixed to the inner circumferential surface of the second gear 32. The first magnet 11 according to this modification is disposed on the input side (drive side) of the second magnet 12.

[0082] In the magnetic gear device 1A, the second magnet 12 is disposed radially inward of the first magnet 11 in the radial direction R, and the second back yoke 122 is fixed to the outer peripheral surface of the second shaft 17. The second magnet 12 according to this modification is disposed on the output side (driven side) of the first magnet 11.

[0083] In the power transmission device according to this modification, when the motor 2 is driven to rotate the second gear 32 in the circumferential direction C, the first back yoke 112 and the first magnet 11 fixed to the second gear 32 rotate in the circumferential direction C together with the second gear 32. Then, changes in the magnetic flux of the first magnetic poles 111 in the first magnet 11 are modulated by the first pole piece 13 and transmitted to the second magnetic poles 121 of the second magnet 12 connected to the driven side. In this case, in the magnetic gear device 1 according to this modification, the number of second magnetic poles 121 of the second magnet 12 arranged inside the first magnet 11 in the radial direction R is fewer than the number of first magnetic poles 111 of the first magnet 11. Therefore, although torque decreases, the rotation speed in the circumferential direction C can be increased. Furthermore, in the magnetic gear device 1A according to this modification, the first magnet 11 has a ring shape in which multiple first magnetic poles 111 are arranged in the circumferential direction C and are integrally formed. Therefore, the magnetic gear device 1A of this modified example can increase speed because the pitch of the multiple first magnetic poles 111 in the circumferential direction C can be narrowed compared to, for example, a magnetic gear device having a ring-shaped first magnet formed by connecting multiple individually formed magnets (for example, the device described in JP 2022-150601 A).

[0084] As described above, in the magnetic gear device 1A according to this modification, the first magnet 11 is disposed outside the second magnet 12 in the radial direction R, and 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. Therefore, the magnetic gear device 1A according to this embodiment can increase the speed of the second shaft 17 (rotational speed on the output side) of the magnetic gear device 1A more than the speed of the first shaft 22 of the motor 2 (rotational speed on the input side). Furthermore, the magnetic gear device 1A according to this modification achieves the same functions and effects as the magnetic gear device 1 according to the first embodiment.

[0085] In the magnetic gear device 1A according to this modification, the second magnet 12 is disposed inside the first magnet 11 in the radial direction R.

[0086] [Second Modification of First Embodiment] Next, a magnetic gear device 1B according to a second modification of the first embodiment will be described using Fig. 5. Fig. 5 is a perspective view of the magnetic gear device 1B according to the second modification of the first embodiment. Note that in the configuration of the magnetic gear device 1B according to the second modification of the first embodiment, the same components as those in the magnetic gear device 1 according to the first embodiment are given the same reference numerals and their description will be omitted. Furthermore, although not shown, a motor 2 and an intermediate transmission mechanism 3 similar to those in the power transmission device 100 according to the first embodiment are arranged on the outside of the magnetic gear device 1B.

[0087] The magnetic gear device 1B of this embodiment has a first magnet 11, a second magnet 12, and a first pole piece 13, and the first magnet 11 and the second magnet 12 face each other in the axial direction A with the first pole piece 13 interposed therebetween.

[0088] The first back yoke 112 of the first magnet 11 is fixed to the outer peripheral surface of the second shaft 17. In other words, the first magnet 11 according to this modification is disposed on the output side (driven side) of the second magnet 12.

[0089] The second back yoke 122 of the second magnet 12 is fixed to the inner circumferential surface of the second gear 32. In other words, the second magnet 12 according to this modification is disposed on the input side (drive side) relative to the first magnet 11.

[0090] As described above, in the magnetic gear device 1B according to this modified example, the first magnet 11 and the second magnet 12 face each other in the axial direction A with the first pole piece 13 interposed therebetween.

[0091] Furthermore, in the magnetic gear device 1B according to this embodiment, the axis of the first magnet 11 and the axis of the second magnet 12 can be arranged coaxially, which facilitates modularization and improves the degree of freedom in layout. Furthermore, the magnetic gear device 1B according to this modification achieves the same actions and effects as the magnetic gear device 1 according to the first embodiment.

[0092] Second Embodiment Fig. 6 is a cross-sectional view of a power transmission device 100C equipped with a magnetic gear device 1C according to a second embodiment. Fig. 7-1 is a perspective view of the magnetic gear device 1C shown in Fig. 6. Fig. 7-2 is a plan view of a second magnetic gear mechanism 1β equipped in the magnetic gear device 1C shown in Fig. 6. Note that in the configuration of the magnetic gear device 1C according to the second 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. Also, for ease of explanation, the motor 2 is omitted in Figs. 7-1 and 7-2. Furthermore, in Fig. 6, the transmission path of the driving force of the motor 2 is indicated by arrow F1.

[0093] In describing the power transmission device 100C equipped with the magnetic gear device 1C shown in Figures 6, 7-1, and 7-2 according to the embodiment, in order to facilitate understanding of the 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.

[0094] 6, 7-1, and 7-2 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. In the power transmission 100C according to this embodiment, an axis 2o of the first shaft 22, which is an input shaft, and an axis 17o of the second shaft 17, which is an output shaft, are arranged parallel to each other. This power transmission 100C includes, for example, a magnetic gear device 1C and a motor 2.

[0095] The power transmission device 100C according to the second 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 100C is housed in a frame (not shown), for example.

[0096] 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.

[0097] The main body 21 is fixed to a frame. Inside the main body 21, devices such as a rotor and a stator are housed.

[0098] 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 2o and is provided rotatably about the axis 2o with respect to the frame and the main body 21. The first shaft 22 also extends, for example, along the axial direction A.

[0099] When the motor 2 having the above configuration is driven, the first shaft 22 rotates around the axis 2o, 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.

[0100] The magnetic gear device 1C includes, for example, a first magnet 11, a second magnet 12, a first pole piece 13, a third magnet 14, a fourth magnet 15, and a second pole piece 16. Furthermore, the magnetic gear device 1C is provided with a second shaft 17. In the magnetic gear device 1C 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, the magnetic gear device 1C is a device in which two-stage magnetic gear mechanisms 1α and 1β are arranged in the axial direction A. More specifically, the magnetic gear device 1C 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.

[0101] 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. 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. In other words, the first magnetic gear mechanism 1α is disposed on the input side (drive side), and the second magnetic gear mechanism 1β is disposed on the output side (driven side).

[0102] The first magnet 11 is provided in the magnetic gear device 1C 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.

[0103] 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.

[0104] 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 inside in the radial direction R. In the magnetic gear device 1C 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.

[0105] The first magnet 11 is provided rotatably about the axis 17o relative to the frame and the first pole piece 13. 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 rotatably about the axis 17o without contacting the first pole piece 13. The first magnet 11 has a plurality (28 pieces) of 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, the plurality of first magnetic poles 111 are arranged such that north poles and south poles alternate in the circumferential direction C. Furthermore, a first back yoke 112 is provided in the first magnet 11 on the inside of the first magnetic poles 111 in the radial direction R.

[0106] 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.

[0107] The first pole piece 13 is composed of a plurality of (e.g., 29) first modulation pieces 131. 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).

[0108] In the magnetic gear mechanism 1α 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 13M of the first 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 first pole piece 13 is fixed, the reduction ratio X1 can be calculated as follows: X1 = 11M ÷ 12M = 26 ÷ 3 = 8.67

[0109] Alternatively, in the magnetic gear mechanism 1α, if the second magnet 12 is the input, the first pole piece 13 is the output, the first magnet 11 is fixed, and the second magnet 12 is located on the input side, the reduction ratio X2 can be calculated as follows: X2 = 13M ÷ 12M = 29 ÷ 3 = 9.67

[0110] 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.

[0111] 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.

[0112] 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.

[0113] 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.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] The second pole piece 16 is composed of a plurality of (e.g., 29) 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).

[0118] 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 1C outputs torque to the outside as the second shaft 17 rotates in the circumferential direction C about the axis 17o.

[0119] Furthermore, in the magnetic gear device 1C according to this embodiment, the first back yoke 112 and the fourth back yoke 152 are integrally formed.

[0120] Furthermore, in the magnetic gear device 1C, the first magnet 11 and the fourth magnet 15 are formed integrally. In other words, in this magnetic gear device 1C, 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, a ring-shaped magnetic body is used and magnetized as described above, so that 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.

[0121] In addition, in the axial direction A of this magnetic gear device 1C, 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.

[0122] 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.

[0123] 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 .

[0124] 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.

[0125] 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 1C 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.

[0126] 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.

[0127] 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

[0128] 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 second magnetic gear mechanism 1β is calculated as follows: X2 = (52 ÷ 2) / (6 ÷ 2) = 8.67

[0129] Therefore, the reduction ratio of the magnetic gear device 1C according to this embodiment is calculated as follows: 8.67×8.67=75.2

[0130] As described above, the power transmission device 100C according to this embodiment has the following configuration: It includes a magnetic gear device 1C. 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 in the radial direction R and magnetically connecting the third magnet 14 and the fourth magnet 15. Additionally, in the magnetic gear device 1C, 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 1C, at least one of the four magnets, the first magnet 11 to the fourth magnet 15, is ring-shaped. Therefore, the magnetic gear device 1C 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, in the magnetic gear device 1C 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 noise generated during operation, prevents dust from being generated during use, and does not require the use of lubricating oil. Furthermore, because the magnetic gear device 1C does not generate dust during use and does not require the use of lubricating oil, it does not require maintenance.Furthermore, compared to a magnetic gear device in which the outer peripheral surface of a ring-shaped first magnet faces the outer peripheral surface of a ring-shaped second magnet and is magnetically connected only by the opposing magnets, the magnetic gear device 1C of this embodiment magnetically connects the first magnetic poles 111 of the multiple first magnets 11 and the second magnetic poles 121 of the multiple second magnets 12 with the first pole piece 13 interposed in the radial direction R, and also magnetically connects the third magnetic poles 141 of the multiple third magnets 14 and the fourth magnetic poles 151 of the multiple fourth magnets 15 with the second pole piece 16 interposed in the radial direction R, thereby enabling an increase in torque density.

[0131] In the magnetic gear device 1C according to this embodiment, the first magnet 11 has a plurality of first magnetic poles 111 integrally formed therein, and the third magnet 14 has a plurality of third magnetic poles 141 integrally formed therein. 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 1C 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.

[0132] In the magnetic gear device 1C according to this embodiment, the first magnet 11 and the fourth magnet 15 are integrally formed. Therefore, compared to a magnetic gear device in which the first magnet 11 and the fourth magnet 15 are formed separately, the magnetic gear device 1C according to this embodiment can improve workability during assembly by reducing the number of parts.

[0133] 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.

[0134] In the magnetic gear device 1C 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. Furthermore, the third magnet 14 is arranged outside the fourth magnet 15 in the radial direction R. The third magnet 14 is arranged outside the fourth magnet 15 in the radial direction R.

[0135] Although the magnetic gear device 1C described above has the first magnet 11 and the fourth magnet 15 formed integrally, the magnetic gear device 1C 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.

[0136] Furthermore, the input and output may be reversed in the magnetic gear device 1C 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.

[0137] Furthermore, in the first magnetic gear mechanism 1α of the magnetic gear device 1C 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 1 according to this embodiment is not limited to this. The fixed and non-fixed parts may be changed as appropriate.

[0138] In the above-described modified example, the power transmission device 100C is described as including the magnetic gear device 1C and the motor 2. However, the power transmission device 100C 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 1C. Furthermore, the motor 2 may be replaced with a generator. Furthermore, the driving source may be something other than the motor 2.

[0139] Furthermore, the magnets 11, 12, 14, and 15 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, 14, and 15 to other components.

[0140] In the magnetic gear device 1C 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.

[0141] Furthermore, in the magnetic gear device 1C according to the embodiment described above, the second magnet 12 has been described as having six (three pole pairs) second magnetic poles 121. However, the number of second magnetic poles 121 of the second magnet 12 according to this embodiment is not limited to this and can be set to any number. The same applies to the fourth magnet 15.

[0142] Furthermore, in the magnetic gear device 1C 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 first 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.

[0143] Furthermore, in the magnetic gear device 1C according to the embodiment described above, the second magnet 12 has a plurality of second magnetic poles 121 arranged in the circumferential direction C, and the plurality of second magnetic poles 121 are integrally formed 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.

[0144] Furthermore, in the magnetic gear device 1C 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 1C according to the present embodiment is not limited to this. For example, the magnetic gear device 1C may have three or more stages of magnetic gear mechanisms arranged in the axial direction A.

[0145] Furthermore, in the magnetic gear device 1C 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 first pole piece 13 is fixed, the speed increase ratio X3 can be calculated as follows: X3 = 11M ÷ 12M = 26 ÷ 3 = 8.67

[0146] Alternatively, in this case, if the first pole piece 13 is the output, the first magnet 11 is the input, and the second magnet 12 is fixed in the first magnetic gear mechanism 1α, the speed increase ratio X4 can be calculated as follows: X4 = 13M ÷ 12M = 29 ÷ 3 = 9.67

[0147] 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 first pole piece 13 is fixed, the reduction ratio X5 can be calculated as follows: X5 = 11M ÷ 12M = 26 ÷ 3 = 8.67.

[0148] Alternatively, in this case, if the first pole piece 13 is the output, the first magnet 11 is fixed, and the second magnet 12 is the input in the first magnetic gear mechanism 1α, the reduction ratio X6 can be calculated as follows: X6 = 13M ÷ 12M = 29 ÷ 3 = 9.67

[0149] [First Modification of Second Embodiment] Next, a magnetic gear device 1D according to a first modification of the second embodiment will be described with reference to FIGS. 8, 9-1, and 9-2. FIG. 8 is a cross-sectional view of a power transmission device 100D including the magnetic gear device 1D according to the first modification of the second embodiment. FIG. 9-1 is a perspective view of the magnetic gear device 1D shown in FIG. 8. FIG. 9-2 is a perspective view showing the other side of the magnetic gear device shown in FIG. 8 in the axial direction A. Note that in the configuration of the magnetic gear device 1D according to the first modification of the second embodiment, the same components as those in the magnetic gear devices 1 and 1C described above are assigned the same reference numerals and their description will be omitted. Also, for ease of explanation, the motor 2 is omitted in FIGS. 9-1 and 9-2. Furthermore, in FIG. 8, the transmission path of the driving force of the motor 2 is indicated by arrow F2.

[0150] This power transmission device 100D includes, for example, a magnetic gear device 1D and a motor 2.

[0151] The magnetic gear device 1D includes a first magnetic gear mechanism 1α and a second magnetic gear mechanism 1β. The magnetic gear device 1D is provided with a second shaft 17. The magnetic gear device 1D 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.

[0152] The first magnetic gear mechanism 1α is composed of a first magnet 11, a second magnet 12, and a first pole piece 13.

[0153] 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.

[0154] 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.

[0155] The second magnetic gear mechanism 1β is composed of a third magnet 14, a fourth magnet 15, and a second pole piece 16.

[0156] 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. The third back yoke 142 is then connected to the second shaft 17.

[0157] 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. Furthermore, the fourth magnet 15 according to this modification is disposed on the input side (drive side) of the third magnet 14.

[0158] In the power transmission device 100D according to this modification, 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.

[0159] In the magnetic gear device 1D 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 1D according to this modification achieves the same actions and effects as the magnetic gear device 1C according to the second embodiment.

[0160] In the magnetic gear device 1D according to the above-described modified example, the two-stage magnetic gear mechanisms 1α and 1β are arranged in the axial direction A. However, the magnetic gear device 1D according to this modified example is not limited to this. For example, the magnetic gear device 1D may have three or more stages of magnetic gear mechanisms arranged in the axial direction A.

[0161] Furthermore, in the magnetic gear device 1D 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 1D according to this modified example is not limited to this. The input side, output side, and fixing points can be changed as appropriate.

[0162] Third Embodiment Next, a magnetic gear device 1E according to a third embodiment will be described with reference to FIGS. 10-1 and 10-2. FIG. 10-1 is a plan view of a power transmission device 100E including the magnetic gear device 1E according to the third embodiment. FIG. 10-2 is a perspective view of the magnetic gear device 1E shown in FIG. 10-1. Note that in the configuration of the power transmission device 100E according to the third embodiment, the same components as those of the power transmission devices 100 and 100C described above are assigned the same reference numerals and their description will be omitted. Also, the motor 2 and intermediate transmission mechanism 3E are omitted in FIG. 10-2.

[0163] The power transmission device 100E according to this embodiment includes a motor 2, an intermediate transmission mechanism 3E, and a magnetic gear device 1E.

[0164] The intermediate transmission mechanism 3E includes, for example, a first gear 31E which is a worm and a second gear 32E which is a worm wheel.

[0165] 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.

[0166] The second gear 32E is coupled to the outer peripheral surface of the second back yoke 122 of the second magnet 12 so as to rotate together with the second magnet 12 in the magnetic gear device 1E in the circumferential direction C. The second gear 32E meshes with the first gear 31E. The intermediate transmission mechanism 3E according to this embodiment is constituted by a mechanical first gear 31E and a mechanical second gear 32E.

[0167] The magnetic gear device 1E includes a first magnetic gear mechanism 1α and a second magnetic gear mechanism 1β. In addition, the magnetic gear device 1E is provided with a second shaft 17. 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 radial direction R.

[0168] The first magnetic gear mechanism 1α is composed of a first magnet 11, a second magnet 12, and a first pole piece 13.

[0169] 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.

[0170] In the first magnetic gear mechanism 1α, the second magnet 12 is disposed radially outward of the first magnet 11 in the radial direction R. A second back yoke 122 is also provided radially outward of the second magnet 12. The outer peripheral surface of the second back yoke 122 is fixed to the inner peripheral surface of the second gear 32E. The second magnet 12 according to this embodiment is disposed on the input side (drive side) of the first magnet 11.

[0171] The second magnetic gear mechanism 1β is composed of a third magnet 14, a fourth magnet 15, and a second pole piece 16.

[0172] 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. A third back yoke 142 is also provided on the inside of the third magnet 14 in the radial direction R. The inner circumferential surface of the third back yoke 142 is fixed to the outer circumferential surface of the second shaft 17. In other words, the third magnet 14 according to this embodiment is disposed on the output side (driven side) of the fourth magnet 15.

[0173] In the second magnetic gear mechanism 1β, the fourth magnet 15 is arranged inside 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 1E 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.

[0174] Furthermore, in the power transmission device 100E 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.

[0175] In the power transmission device 100E according to this embodiment, when the motor 2 is driven to rotate the second gear 32E in the circumferential direction C, the second back yoke 122 and the second magnet 12 fixed to the second gear 32E rotate in the circumferential direction C together with the second gear 32E. 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.

[0176] The power transmission device 100E according to this embodiment includes a magnetic gear device 1E having the following configuration: 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 first magnet 11 and the fourth magnet 15 are connected in the radial direction R of the magnetic gear device 1E, 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 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. In the magnetic gear device 1E, at least one of the four magnets, the first magnet 11 to the fourth magnet 15, is ring-shaped. Therefore, the power transmission device 100E 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 100E according to this embodiment has the same functions and effects as the power transmission device 100C according to the second embodiment.

[0177] In the power transmission device 100E 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.

[0178] In the power transmission device 100E 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.

[0179] Although the power transmission device 100E described above has the first magnet 11 and the fourth magnet 15 formed integrally, the power transmission device 100E 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.

[0180] Furthermore, in the magnetic gear device 1E 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 1E according to the present embodiment is not limited to this. For example, the magnetic gear device 1E can have three or more stages of magnetic gear mechanisms arranged in the radial direction R. Furthermore, a three-stage magnetic gear device can be configured by combining the magnetic gear device 1E according to the embodiment described above with the magnetic gear device 1D.

[0181] 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. The input side, output side, and fixed locations can be changed as appropriate.

[0182] [First Modification of Third Embodiment] Next, a magnetic gear device 1F according to a first modification of the third embodiment will be described with reference to FIGS. 11-1 and 11-2. FIG. 11-1 is a plan view of a power transmission device 100F including the magnetic gear device 1F according to the first modification of the third embodiment. FIG. 11-2 is a perspective view of the magnetic gear device 1F shown in FIG. 11-1. Note that in the configuration of the power transmission device 100F according to the first modification of the third embodiment, the same components as those of the power transmission devices 100, 100C, and 100E described above are assigned the same reference numerals and their description will be omitted. Also, the motor 2 and intermediate transmission mechanism 3E are omitted in FIG. 11-2.

[0183] A power transmission device 100F according to this modification includes a motor 2, an intermediate transmission mechanism 3E, and a magnetic gear device 1F.

[0184] The magnetic gear device 1F includes a first magnetic gear mechanism 1α and a second magnetic gear mechanism 1β. The magnetic gear device 1F is also provided with a second shaft 17. The magnetic gear device 1F 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.

[0185] The first magnetic gear mechanism 1α is composed of a first magnet 11, a second magnet 12, and a first pole piece 13.

[0186] In the first magnetic gear mechanism 1α, the first magnet 11 is disposed radially outward of the second magnet 12 in the radial direction R. A first back yoke 112 is provided radially outward of the first magnet 11. The outer peripheral surface of the first back yoke 112 is fixed to the inner peripheral surface of the second gear 32E. The first magnet 11 according to this modification is disposed on the input side (drive side) of the second magnet 12.

[0187] 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.

[0188] The second magnetic gear mechanism 1β is composed of a third magnet 14, a fourth magnet 15, and a second pole piece 16.

[0189] 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.

[0190] In the second magnetic gear mechanism 1β, the fourth magnet 15 is disposed outside the third magnet 14 in the radial direction R. A fourth back yoke 152 is provided inside the fourth magnet 15 in the radial direction R. The inner circumferential surface of the fourth back yoke 152 is fixed to the outer circumferential surface of the second shaft 17. In other words, the fourth magnet 15 in this modified example is disposed on the output side (driven side) with respect to the third magnet 14. In the magnetic gear device 1F according to this embodiment, the first magnet 11, the second magnet 12, the third magnet 14, and the fourth magnet 15 are disposed so as to be rotatable about a common axis 17o.

[0191] Furthermore, in the power transmission device 100F 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 1F, 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.

[0192] In the power transmission device 100F according to this modified example, when the motor 2 is driven to rotate the second gear 32E in the circumferential direction C, the first back yoke 112 and the first magnet 11 fixed to the second gear 32E rotate in the circumferential direction C together with the second gear 32E. 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.

[0193] A power transmission device 100F according to this modified example includes a magnetic gear device 1F having the following configuration: 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 magnetic gear device 1F, 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 100F 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 100F according to this embodiment achieves the same functions and effects as the power transmission device 100C according to the second embodiment.

[0194] In the power transmission device 100F 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.

[0195] In the power transmission device 100F 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.

[0196] While the power transmission device 100F described above is one in which the second magnet 12 and the third magnet 14 are integrally formed, the power transmission device 100F 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 1F according to the modification described above with a magnetic gear device 1D in which the input and output are reversed.

[0197] 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. The input side, output side, and fixing points can be changed as appropriate.

[0198] [Fourth Embodiment] Next, a power transmission device 100G according to a fourth embodiment will be described with reference to Fig. 12. Fig. 12 is a plan view of the power transmission device 100G according to the fourth embodiment. Note that in the configuration of the power transmission device 100G according to the fourth 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.

[0199] The power transmission device 100G according to this embodiment includes a magnetic gear device 1, a motor 2, and an intermediate transmission mechanism 3. The power transmission device 100G according to this embodiment is arranged so that the axis 2o 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 100G according to this embodiment is a parallel-axis device in which the axis 2o of the input shaft and the axis 17o of the output shaft are parallel to each other.

[0200] As described above, in the power transmission device 100G according to this embodiment, the axis 2o 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 100G according to this embodiment can be easily modularized and can improve the degree of freedom in layout.

[0201] The power transmission device 100G described above includes the magnetic gear device 1, the motor 2, and the intermediate transmission mechanism 3. However, the power transmission device 100G according to this embodiment is not limited to this. For example, the intermediate transmission mechanism 3 can be appropriately modified, and any one of the magnetic gear devices 1A, 1B, 1C, 1D, 1E, and 1F can be applied instead of the magnetic gear device 1.

[0202] Fifth Embodiment Next, a power transmission device 100H according to a fifth embodiment will be described with reference to Fig. 13. Fig. 13 is a cross-sectional view of the power transmission device 100H according to the fifth embodiment. Note that in the configuration of the power transmission device 100H 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.

[0203] The power transmission device 100H according to this embodiment includes a magnetic gear device 1, a motor 2, and an intermediate transmission mechanism 3H. In the power transmission device 100H 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 parallel to each other. In other words, the power transmission device 100H 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 arranged parallel to each other.

[0204] The intermediate 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.

[0205] The rack gear 312 extends, for example, perpendicular to the direction in which the first shaft 22 extends. The rack gear 312 has a plurality of teeth. In the intermediate transmission mechanism 3H, the teeth of the rack gear 312 mesh with the teeth of the pinion gear 313.

[0206] An output shaft (not shown) of the motor is fixed to the second shaft 17. Therefore, when the motor of this power transmission mechanism 1H is driven, the second magnet 12 is driven, which causes the first magnet 11 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 first magnet 11. 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.

[0207] The power transmission device 100H described above includes the magnetic gear device 1, the motor 2, and the intermediate transmission mechanism 3. However, the power transmission device 100H according to this embodiment is not limited to this. For example, the intermediate transmission mechanism 3 can be appropriately modified, and any one of the magnetic gear devices 1A, 1B, 1C, 1D, 1E, and 1F can be applied instead of the magnetic gear device 1.

[0208] Sixth Embodiment Next, a power transmission device 100I according to a sixth 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 sixth embodiment. Note that in the configuration of the power transmission device 100I according to the sixth embodiment, the same components as those of the power transmission device 100 according to the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0209] 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 2o 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 2o of the input shaft and the axis 17o of the output shaft are perpendicular to each other.

[0210] 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.

[0211] 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.

[0212] The power transmission device 100I described above includes the magnetic gear device 1, the motor 2, and the intermediate transmission mechanism 3. However, the power transmission device 100I according to this embodiment is not limited to this. For example, the intermediate transmission mechanism 3 can be appropriately modified, and any one of the magnetic gear devices 1A, 1B, 1C, 1D, 1E, and 1F can be applied instead of the magnetic gear device 1.

[0213] Seventh Embodiment Next, a power transmission device 100J according to a seventh embodiment will be described with reference to Figures 15 and 16. Figure 15 is a cross-sectional view of the power transmission device 100J according to the seventh embodiment. Figure 16 is a front view of an intermediate transmission mechanism 3J included in the power transmission device 100J shown in Figure 15. Note that in the configuration of the power transmission device 100J according to the seventh embodiment, the same components as those in the power transmission device 100C according to the second embodiment are designated by the same reference numerals, and description thereof will be omitted.

[0214] The power transmission device 100J according to this embodiment includes a magnetic gear device 1C, a motor 2, and an intermediate transmission mechanism 3J. The power transmission device 100J according to this embodiment is arranged so that the axis 2o 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 100J according to this embodiment is a device in which the axis 2o of the input shaft and the axis 17o of the output shaft are coaxial.

[0215] The intermediate transmission mechanism 3J 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.

[0216] 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.

[0217] 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 3J 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.

[0218] 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 3J 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.

[0219] 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 3J so as to be rotatable about the axis 2 o in accordance with the revolution of the planetary gears 303. Furthermore, in the intermediate transmission mechanism 3J according to this embodiment, the planetary carrier 304 is coupled to the back yoke 122 of the second magnet 12.

[0220] Next, a description will be given of the power transmission device 100J according to this embodiment when the motor 2 is driven. When the motor 2 is driven in the power transmission device 100J, the sun gear 301 rotates about the axis 2o together with the rotation of the first shaft 22.

[0221] 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 2o in conjunction with the revolution of the planetary gears 303.

[0222] 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 2o. 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.

[0223] As described above, in the power transmission device 100J according to this embodiment, the axis 2o 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 100J according to this embodiment can be easily modularized and can improve the degree of freedom in layout. Furthermore, this power transmission device 100J can increase torque in the intermediate transmission mechanism 3J, which is a planetary gear mechanism. Therefore, when this intermediate transmission mechanism 3J is combined with a magnetic gear mechanism that increases torque, torque can be further increased.

[0224] The power transmission device 100J described above includes the magnetic gear device 1C, the motor 2, and the intermediate transmission mechanism 3J. However, the power transmission device 100J according to this embodiment is not limited to this. For example, any one of the magnetic gear devices 1, 1A, 1B, 1D, 1E, and 1F may be applied in place of the magnetic gear device 1C.

[0225] [First Modification of Seventh Embodiment] Next, a power transmission device 100K according to a first modification of the seventh embodiment will be described using FIG. 17. FIG. 17 is a cross-sectional view of the power transmission device 100K according to the first modification of the seventh embodiment. Note that in the configuration of the power transmission device 100K according to the first modification of the seventh embodiment, the same components as those in the power transmission device 100D according to the first modification of the second embodiment and those in the power transmission device 100J according to the seventh embodiment are assigned the same reference numerals and description thereof will be omitted. FIG. 17 also shows a portion of the second magnetic gear mechanism 1β in the magnetic gear device 1D connected to the intermediate transmission mechanism 3K.

[0226] The power transmission device 100K according to this modification includes the second magnetic gear mechanism 1β of the magnetic gear device 1D, a motor 2, and an intermediate transmission mechanism 3K.

[0227] The intermediate transmission mechanism 3K shown in this embodiment is a planetary gear mechanism. The intermediate transmission mechanism 3K, 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.

[0228] In the intermediate transmission mechanism 3K according to this modified example, the planetary carrier 304 is connected to the second back yoke 122 .

[0229] Next, a description will be given of the power transmission device 100K according to this embodiment when the motor 2 is driven. When the motor 2 is driven in the power transmission device 100K, the sun gear 301 rotates about the axis 2o together with the rotation of the first shaft 22.

[0230] 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 2o in conjunction with the revolution of the planetary gears 303.

[0231] Furthermore, because the planetary carrier 304 is connected to the second back yoke 122 of the magnetic gear device 1D, the second back yoke 122 and the second magnet 12 rotate about the axis 17o as the planetary carrier 304 rotates about the axis 2o. Therefore, similar to the power transmission device 100D according to the first modified example of the second 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.

[0232] As described above, in the power transmission device 100K according to this modification, the axis 2o 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 100L according to this embodiment can be easily modularized and can improve the degree of freedom in layout. Furthermore, this power transmission device 100K can increase torque in the intermediate transmission mechanism 3K, which is a planetary gear mechanism. Therefore, when this intermediate transmission mechanism 3K is combined with the magnetic gear mechanism 1β, which can increase torque, torque can be further increased.

[0233] The power transmission device 100K described above includes the magnetic gear device 1D, the motor 2, and the intermediate transmission mechanism 3K. However, the power transmission device 100K according to this embodiment is not limited to this. For example, any one of the magnetic gear devices 1, 1A, 1B, 1C, 1E, and 1F may be applied in place of the magnetic gear device 1D.

[0234] [Second Modification of Seventh Embodiment] Next, a power transmission device 100L according to a second modification of the seventh embodiment will be described with reference to Fig. 18. Fig. 18 is a cross-sectional view of the power transmission device 100L according to the second modification of the seventh embodiment. Note that in the configuration of the power transmission device 100L according to the second modification of the seventh embodiment, the same components as those of the power transmission device 100C according to the second embodiment and the power transmission device 100J according to the seventh embodiment will be assigned the same reference numerals and descriptions thereof will be omitted.

[0235] The power transmission device 100L according to this modification includes a magnetic gear device 1C, a motor 2, and an intermediate transmission mechanism 3L.

[0236] The intermediate transmission mechanism 3L shown in this embodiment is a planetary gear mechanism. The intermediate transmission mechanism 3L, 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.

[0237] In the intermediate transmission mechanism 3L according to this modification, 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 3L 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.

[0238] Next, a description will be given of the power transmission device 100L according to this embodiment when the motor 2 is driven. When the motor 2 is driven in the power transmission device 100L, the sun gear 301 rotates about the axis 2o together with the rotation of the first shaft 22.

[0239] 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 rotate, the ring gear 302 rotates around the axis 2o in conjunction with the rotation of the planetary gears 303, because the planet carrier 304 is connected to the frame.

[0240] 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 2o. 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.

[0241] As described above, in the power transmission device 100L according to this embodiment, the axis 2o 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 100L according to this embodiment can be easily modularized and can improve the degree of freedom in layout. Furthermore, this power transmission device 100L can also increase torque in the intermediate transmission mechanism 3L, which is a planetary gear mechanism, thereby further increasing torque.

[0242] The power transmission device 100L described above includes the magnetic gear device 1C, the motor 2, and the intermediate transmission mechanism 3L. However, the power transmission device 100L according to this embodiment is not limited to this. For example, any one of the magnetic gear devices 1, 1A, 1B, 1D, 1E, and 1F may be applied in place of the magnetic gear device 1C.

[0243] [Third Modification of Seventh Embodiment] Next, a power transmission device 100M according to a third modification of the seventh embodiment will be described using FIGS. 19 and 20. FIG. 19 is a cross-sectional view of the power transmission device 100M according to the third modification of the seventh embodiment. FIG. 20 is a front view of the intermediate transmission mechanism 3M included in the power transmission device 100M shown in FIG. 19. Note that, in the configuration of the power transmission device 100M according to the third modification of the seventh embodiment, the same components as those of the power transmission device 100D according to the first modification of the second embodiment and the power transmission device 100J according to the seventh embodiment are denoted by the same reference numerals and description thereof will be omitted. FIG. 19 also shows a portion of the second magnetic gear mechanism 1β in the magnetic gear device 1D connected to the intermediate transmission mechanism 3M.

[0244] The power transmission device 100M according to this modification includes the second magnetic gear mechanism 1β of the magnetic gear device 1D, a motor 2, and an intermediate transmission mechanism 3M.

[0245] The intermediate transmission mechanism 3M shown in this embodiment is a planetary gear mechanism. The intermediate transmission mechanism 3M, 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.

[0246] In the intermediate transmission mechanism 3M 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).

[0247] Next, a description will be given of the power transmission device 100M according to this embodiment when the motor 2 is driven. When the motor 2 is driven in the power transmission device 100M, the planet carrier 304 rotates about the axis 2o.

[0248] The rotation of the planet carrier 304 causes the multiple planetary gears 303 to rotate about the axis 303o of the planet shaft 303a while meshing with the ring gear 302, and also to revolve around the periphery of the sun gear 301. When the planetary gears 303 revolve, the sun gear 301 rotates about the axis 2o. Because the sun gear 301 according to this modification is connected to the second shaft 17 via the axis 305, the third back yoke 142 rotates about the axis 17o as the sun gear 301 rotates.

[0249] Therefore, the third magnet 14 rotates together with the rotation of the sun gear 301, and this rotation causes the fourth magnet 15 to rotate.

[0250] As described above, in the power transmission device 100M according to this modified example, the axis 2o 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 100M according to this embodiment can be easily modularized and can improve layout flexibility. Furthermore, this power transmission device 100M can increase speed in the intermediate transmission mechanism 3M, which is a planetary gear mechanism. Therefore, when the above-described magnetic gear mechanism 1α is applied to the power transmission device 100M, speed can be further increased. Therefore, when the power transmission device 100M is coupled to a magnetic gear mechanism 1β, which increases speed, speed can be further increased.

[0251] The power transmission device 100M described above includes the magnetic gear device 1D, the motor 2, and the intermediate transmission mechanism 3M. However, the power transmission device 100M according to this embodiment is not limited to this. For example, any one of the magnetic gear devices 1, 1A, 1B, 1C, 1E, and 1F may be applied in place of the magnetic gear device 1D.

[0252] The intermediate transmission mechanisms 3J, 3K, and 3M according to the seventh 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 3L 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 3J, 3K, 3L, and 3M 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.

[0253] 21 is a plan view of a power transmission device 100N according to an eighth embodiment. In the configuration of the power transmission device 100N according to the eighth embodiment, the same components as those of the power transmission device 100 according to the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0254] 21 according to this embodiment transmits the driving force of a motor 2N to the outside. In addition, in this power transmission 100N, the driving force of a motor 2N is directly transmitted to a magnetic gear device 1. The power transmission 100N includes, for example, the magnetic gear device 1 and a motor 2N.

[0255] The motor 2N is an outer rotor type in which the rotor 24 is disposed outside the stator 23 in the radial direction R.

[0256] The motor 2N includes, for example, a stator 23 and a rotor 24 that is rotatable in the circumferential direction C relative to the stator 23. The motor 2N is an electric motor that converts electrical energy supplied from a power source into mechanical energy (energy that rotates the rotor 24 in the circumferential direction C). Note that the motor 2N according to this embodiment is an outer rotor type in which the rotor 24 is disposed outside the stator 23 in the radial direction R.

[0257] The stator 23 is a part that generates a force for rotating the rotor 24 in the circumferential direction C. The stator 23 includes a yoke 231 formed in an annular shape, teeth 232 that protrude inward in the radial direction R from the inner circumferential surface of the yoke 231, coils 233 wound around the teeth 232, and insulators (not shown) that electrically insulate the teeth 232 and the coils 233.

[0258] In the stator 23 according to this embodiment, the yoke 231 and the teeth 232 are formed by punching out flat plate-shaped members made of a magnetic material (magnetic substance) such as an electromagnetic steel plate, and stacking a plurality of the members in the axial direction A. In other words, the yoke 231 and the teeth 232 are made of a magnetic material (magnetic substance).

[0259] The coil 233 is electrically connected to, for example, a power supply. When the motor 2N is driven, a voltage is applied from the power supply to the coil 233, which generates a magnetic field in the coil 233 that changes over time. The interaction between this magnetic field and the magnetic force of the rotor magnet 241 causes the rotor 24 to rotate in the circumferential direction C relative to the stator 23.

[0260] Next, the rotor 24 will be described. The rotor 24 is rotatably disposed on the outer side of the stator 23 in the radial direction R. The rotor 24 has a plurality of rotor magnets 241. The rotor magnet 241 is, for example, ring-shaped, and has a plurality of magnetic poles (six poles in this embodiment) formed integrally. The rotor magnet 241 is also fixed to the inner circumferential surface of the second back yoke 122 of the second magnet 12, and rotates together with the second magnet 12 and the second back yoke 122. In other words, in the power transmission device 100 according to this embodiment, the magnetic gear device 1 and the motor 2N are integrated.

[0261] When the motor 2N having the above configuration is driven, the rotor 24 rotates relative to the stator 23 about the axis 2o.

[0262] The magnetic gear device 1 is a so-called flux modulation type magnetic gear (harmonic type magnetic gear device) that includes a first magnet 11, a second magnet 12, and a first pole piece 13.

[0263] As described above, the power transmission device 100N according to this embodiment can be constructed by attaching the magnetic gear device 1 to the outer peripheral surface of the rotor magnet 221 in the radial direction R, so that the magnetic gear device 1 can be easily retrofitted to the motor 2N. Furthermore, the power transmission device 100N according to this embodiment achieves the same functions and effects as the power transmission device 100 of the first embodiment.

[0264] The power transmission device 100N described above includes a magnetic gear device 1 and a motor 2N. However, the power transmission device 100N according to the present embodiment is not limited to this. For example, any one of the magnetic gear devices 1A, 1B, 1C, 1D, 1E, and 1F may be applied instead of the magnetic gear device 1.

[0265] 22 is a plan view of a power transmission device 100O according to a first modification of the eighth embodiment. In the configuration of the power transmission device 100O according to the first modification of the eighth embodiment, the same components as those of the power transmission device 100 according to the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0266] This power transmission device 100O includes, for example, a magnetic gear device 1 and a motor 2O.

[0267] The motor 20 is an inner rotor type in which the rotor 24 is disposed inside the stator 23 in the radial direction R.

[0268] In the magnetic gear device 1, the first magnet 11 is arranged on the inside in the radial direction R, and the second magnet 12 is arranged on the outside in the radial direction R of the first magnet 11.

[0269] The power transmission device 100O according to this embodiment has the same functions and effects as the power transmission device 100N according to the eighth embodiment.

[0270] Furthermore, the power transmission device 100O of this embodiment can be constructed by attaching the magnetic gear device 1 to the inner surface of the rotor magnet 241 in the radial direction R, so that the magnetic gear device 1 can be easily retrofitted to the motor 2O.

[0271] The power transmission device 100O described above includes the magnetic gear device 1 and the motor 2O. However, the power transmission device 100O according to the present embodiment is not limited to this. For example, any one of the magnetic gear devices 1A, 1B, 1C, 1D, 1E, and 1F may be applied instead of the magnetic gear device 1.

[0272] 23 is a plan view of a power transmission device 100P according to a second modification of the eighth embodiment. In the configuration of the power transmission device 100P according to the second modification of the eighth embodiment, the same components as those of the power transmission devices 100 and 100N described above are denoted by the same reference numerals, and description thereof will be omitted.

[0273] This power transmission device 100P includes, for example, a magnetic gear device 1 and a motor 2N.

[0274] The motor 2N is an outer rotor type in which the rotor 24 is disposed outside the stator 23 in the radial direction R.

[0275] The second magnet 12 located on the inner side in the radial direction R faces the stator 23 in the radial direction R, and also functions as a rotor magnet for the rotor 24 in the motor 2N.

[0276] In the magnetic gear device 1, the second magnet 12 located on the inner side in the radial direction R is not provided with a second back yoke.

[0277] The power transmission device 100P according to this embodiment has the same functions and effects as the power transmission device 100 according to the first embodiment.

[0278] Furthermore, in the power transmission device 100P according to this embodiment, the second magnet 12 of the magnetic gear device 1 faces the stator 23 in the radial direction R and also functions as a rotor magnet for the rotor 24 of the motor 2N. Therefore, there is no need to form the second magnet 12 and the rotor magnet separately, which reduces the number of parts and improves work efficiency during assembly.

[0279] The power transmission device 100P described above includes a magnetic gear device 1 and a motor 2N. However, the power transmission device 100P according to this embodiment is not limited to this. For example, any one of the magnetic gear devices 1A, 1B, 1C, 1D, 1E, and 1F may be applied instead of the magnetic gear device 1.

[0280] 24 is a plan view of a power transmission device 100Q according to a third modified example of the eighth embodiment. In the configuration of the power transmission device 100Q according to the third modified example of the eighth embodiment, the same components as those of the power transmission devices 100, 100N, and 100O described above are denoted by the same reference numerals, and description thereof will be omitted.

[0281] This power transmission device 100Q includes, for example, a magnetic gear device 1 and a motor 2O.

[0282] The motor 20 is an inner rotor type in which the rotor 24 is disposed inside the stator 23 in the radial direction R.

[0283] In the magnetic gear device 1, the first magnet 11 is arranged on the inside in the radial direction R, and the second magnet 12 is arranged on the outside in the radial direction R of the first magnet 11.

[0284] The second magnet 12 located on the outer side in the radial direction R faces the stator 23 in the radial direction R and also functions as a rotor magnet for the rotor 24 in the motor 2O.

[0285] In the magnetic gear device 1, the second magnet 12 located on the outer side in the radial direction R is not provided with a second back yoke.

[0286] The power transmission device 100Q according to this embodiment achieves the same functions and effects as the power transmission device 100 according to the first embodiment. Furthermore, in the power transmission device 100Q according to this embodiment, the second magnet 12 of the magnetic gear device 1 faces the stator 23 in the radial direction R, and also functions as a rotor magnet for the rotor 24 of the motor 20. Therefore, there is no need to form the second magnet 12 and the rotor magnet separately, which reduces the number of parts and improves work efficiency during assembly.

[0287] The power transmission device 100Q described above includes the magnetic gear device 1 and the motor 2O. However, the power transmission device 100Q according to the present embodiment is not limited to this. For example, instead of the magnetic gear device 1, any one of the magnetic gear devices 1A, 1B, 1C, 1D, 1E, and 1F may be applied.

[0288] 25 is a plan view of a power transmission device 100R according to a fourth modification of the eighth embodiment. In the configuration of the power transmission device 100R according to the fourth modification of the eighth embodiment, the same components as those of the power transmission devices 100 and 100N described above are denoted by the same reference numerals, and description thereof will be omitted.

[0289] This power transmission device 100R includes, for example, a magnetic gear device 1 and a motor 2N.

[0290] The motor 2N is an outer rotor type in which the rotor 24 is disposed outside the stator 23 in the radial direction R.

[0291] In the power transmission device 100R, the rotor magnet 241 and the second magnet 12 are integrally formed.

[0292] Therefore, in this power transmission device 100R, the rotor magnet 241 and the second magnet 12 are connected in the radial direction R, and the second magnet 12 rotates together with the rotor magnet 241 in the circumferential direction C. To explain the rotor magnet 241 and the second magnet 12 more specifically, a ring-shaped magnetic body is used and magnetized as described above, so that the rotor magnet 241 is formed on the inside in the radial direction R, and the second magnet 12 is formed on the outside in the radial direction R. In this embodiment, the number of rotor magnets 241 and the number of second magnets 12 are different, but they may also be the same.

[0293] In the magnetic gear device 1, the second magnet 12 located on the inner side in the radial direction R is not provided with a second back yoke.

[0294] The power transmission device 100R according to this embodiment has the same functions and effects as the power transmission device 100 according to the first embodiment. Furthermore, in the power transmission device 100R according to this embodiment, the rotor magnet 241 and the second magnet 12 are integrally formed, which improves the efficiency of assembly.

[0295] The power transmission device 100R described above includes the magnetic gear device 1 and the motor 2N. However, the power transmission device 100R according to this embodiment is not limited to this. For example, instead of the magnetic gear device 1, any one of the magnetic gear devices 1A, 1B, 1C, 1D, 1E, and 1F may be applied.

[0296] 26 is a plan view of a power transmission device 100S according to a fifth modified example of the eighth embodiment. In the configuration of the power transmission device 100S according to the fifth modified example of the eighth embodiment, the same components as those of the power transmission devices 100 and 100O described above are denoted by the same reference numerals, and the description thereof will be omitted.

[0297] This power transmission device 100S includes, for example, a magnetic gear device 1 and a motor 2O.

[0298] The motor 20 is an inner rotor type in which the rotor 24 is disposed inside the stator 23 in the radial direction R.

[0299] In the power transmission device 100S, the rotor magnet 241 and the second magnet 12 are integrally formed.

[0300] Therefore, in this power transmission device 100S, the rotor magnet 241 and the second magnet 12 are connected in the radial direction R, and the second magnet 12 rotates together with the rotor magnet 241 in the circumferential direction C. To explain the rotor magnet 241 and the second magnet 12 more specifically, a ring-shaped magnetic body is used and magnetized as described above, so that the rotor magnet 241 is formed on the inside in the radial direction R, and the second magnet 12 is formed on the outside in the radial direction R. In this embodiment, the number of rotor magnets 241 and the number of second magnets 12 are different, but they may also be the same.

[0301] In the magnetic gear device 1, the second magnet 12 located on the inner side in the radial direction R is not provided with a second back yoke.

[0302] The power transmission device 100S according to this embodiment has the same functions and effects as the power transmission device 100 according to the first embodiment. Furthermore, in the power transmission device 100S according to this embodiment, the rotor magnet 241 and the second magnet 12 are integrally formed, which improves the efficiency of assembly.

[0303] The power transmission device 100S described above includes the magnetic gear device 1 and the motor 20. However, the power transmission device 100S according to this embodiment is not limited to this. For example, any one of the magnetic gear devices 1A, 1B, 1C, 1D, 1E, and 1F may be applied instead of the magnetic gear device 1.

[0304] The above describes the power transmission devices 100, 100A, 100B, 100C, 100D, 100E, 100F, 100G, 100H, 100I, 100J, 100K, 100L, 100M, 100N, 100O, 100P, 100Q, 100R, and 100S according to the present invention based on their embodiments and modifications. However, the present invention is not limited to these embodiments and modifications, and various modifications are possible without departing from the spirit of the present invention. The present invention also includes configurations that combine elements of the above-described embodiments and modifications. Such modifications without departing from the spirit of the present invention are also within the technical scope of the present invention, as will be apparent to those skilled in the art from the appended claims.

[0305] REFERENCE SIGNS LIST 1, 1A, 1B, 1C, 1D, 1E, 1F 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, 100K, 100L, 100M, 100N, 100O, 100P, 100Q, 100R, 100S power transmission device, 41 calculation unit, A axial direction, C circumferential direction, R radial direction, SE1 first sensor, SE2, SE21, SE22 Second sensor

Claims

1. A power transmission device comprising: an input side device; and a magnetic gear device to which the driving force of the input side device is directly or indirectly transmitted, wherein the magnetic gear device is a harmonic type magnetic gear device and comprises at least: 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 pole piece located between the first magnet and the second magnet and magnetically connecting the first magnet and the second magnet; a first sensor that detects changes in magnetic flux density at a detection point of the magnetic field created by the magnetic pole of either the first magnet or the second magnet; and a calculation unit that outputs information about the magnetic gear device based on the detection result of the first sensor.

2. A power transmission device as described in claim 1, further comprising a second sensor that detects changes in magnetic flux density at a detection point of the magnetic field created by the other magnetic pole of the first magnet and the second magnet, at a different position in the circumferential direction from the first sensor, and the calculation unit outputs the rotational angle position of the target ring-shaped magnet based on the detection results of the first sensor and the second sensor.

3. A power transmission device as described in claim 1, further comprising a second sensor that detects changes in magnetic flux density at a detection point of the magnetic field created by the other magnetic poles of the first magnet and the second magnet, wherein the calculation unit outputs information relating to the torque in the magnetic gear device based on the detection results of the first sensor and the second sensor.

4. A power transmission device as described in claim 2 or 3, wherein 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 first magnet is formed with the plurality of first magnetic poles integrally.

5. A power transmission device as described in claim 2 or 3, wherein the magnetic gear device further comprises: a ring-shaped third magnet having a plurality of third magnetic poles arranged in the circumferential direction; a ring-shaped fourth magnet having a plurality of fourth magnetic poles arranged in the circumferential direction; and a second pole piece located radially between the third magnet and the fourth magnet and magnetically connecting the third magnet and the fourth magnet.

6. A power transmission device as described in claim 5, 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, the first magnet is integrally formed with the plurality of first magnetic poles, and the third magnet is integrally formed with the plurality of third magnetic poles.

7. A power transmission device as described in claim 5, 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, the first magnet is integrally formed with the plurality of first magnetic poles, and the third magnet is integrally formed with the plurality of third magnetic poles.

8. A power transmission device as described in claim 5, wherein the second magnet and the third magnet are connected in the radial direction, the third magnet rotates together with the second 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, the first magnet is integrally formed with the plurality of first magnetic poles, and the third magnet is integrally formed with the plurality of third magnetic poles.

9. A power transmission device as described in claim 2 or 3, wherein the input side device is a motor having a stator and a rotor rotatably arranged relative to the stator, the motor being either an inner rotor type in which the rotor is arranged inside the stator in the radial direction, or an outer rotor type in which the rotor is arranged outside the stator, the rotor having a plurality of rotor magnets, and the plurality of rotor magnets are arranged along the circumferential direction, and the rotor magnet and either the first magnet or the second magnet are arranged so as to face each other in the radial direction.

10. A power transmission device as described in claim 2 or 3, wherein the input device is a motor having a stator and a rotor rotatably arranged relative to the stator, the motor being either an inner rotor type in which the rotor is arranged inside the stator in the radial direction, or an outer rotor type in which the rotor is arranged outside the stator, and either the first magnet or the second magnet faces the stator in the radial direction and also functions as a rotor magnet for the rotor in the motor.

11. A power transmission device according to claim 10, wherein the rotor magnet and either the first magnet or the second magnet that faces the rotor magnet in the radial direction are formed separately.

12. A power transmission device according to claim 10, wherein the rotor magnet and either the first magnet or the second magnet that faces the rotor magnet in the radial direction are integrally formed.

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