Motive force transmission device

Abstract

A motive force transmission device (100) comprises: a motor (2) that has a stator (21) and a rotor (22) that is provided so as to be capable of rotating relative to the stator (21); and a magnetic gear device (1) to which drive force is transmitted directly from the motor (2). The magnetic gear device (1) comprises at least: a first magnet (11) at which a plurality of first magnetic poles (111) are arranged in the circumferential direction (C); a second magnet (12) at which a plurality of second magnetic poles (121) are arranged in the circumferential direction (C); and a pole piece (13) that is positioned between the first magnet (11) and the second magnet (12) and magnetically connects the first magnet (11) and the second magnet (12). At least one of the first magnet (11) and the second magnet (12) is ring-shaped, and the magnetic gear device (1) is a harmonic-type magnetic gear device.

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 an inner magnet in which multiple magnets are arranged in a circumferential direction, and an outer magnet in which multiple magnets are arranged in a circumferential direction, with the outer magnet arranged radially outside the inner magnet (see, for example, Patent Document 1).

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

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

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

[0006] In order to solve the above-mentioned problems and achieve the object, a power transmission device according to the present invention includes a motor having a stator and a rotor rotatable relative to the stator, and a magnetic gear device to which driving force of the motor is directly transmitted. The magnetic gear device includes 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, and a pole piece located between the first magnet and the second magnet and magnetically connecting the first magnet and the second magnet. At least one of the first magnet and the second magnet is ring-shaped, and the magnetic gear device is a harmonic magnetic gear device.

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

[0008] FIG. 1 is a plan view of a power transmission device including a magnetic gear device according to the first embodiment. FIG. 2 is a perspective view of the magnetic gear device shown in FIG. 1. FIG. 3 is a cross-sectional view of the magnetic gear device shown in FIG. 1. FIG. 4 is a plan view of a power transmission device including 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 a third modified example of the first 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 a fourth modified example of the first 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 is a plan view of a power transmission device 100E including a magnetic gear device according to a fifth modified example of the first embodiment. FIG. 11 is a perspective view of the magnetic gear device shown in FIG. 10. Fig. 12 is a plan view of a power transmission device including a magnetic gear device according to a sixth modified example of the first embodiment. Fig. 13 is a perspective view of the magnetic gear device shown in Fig. 12. Fig. 14 is a plan view of a power transmission device including a magnetic gear device according to a second embodiment. Fig. 15 is a plan view of a power transmission device including a magnetic gear device according to a third embodiment. Fig. 16 is a plan view of a power transmission device including a magnetic gear device according to a fourth embodiment. Fig. 17 is a plan view of a power transmission device including a magnetic gear device according to a fifth embodiment. Fig. 18 is a plan view of a power transmission device including a magnetic gear device according to a sixth 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 is a plan view of a power transmission device 100 including a magnetic gear device 1 according to a first embodiment. Fig. 2 is a perspective view showing the magnetic gear device 1 shown in Fig. 1. Fig. 3 is a cross-sectional view of the magnetic gear device 1 shown in Fig. 1. For ease of explanation, the motor 2 is omitted from Fig. 2.

[0011] In describing the power transmission device 100 including the magnetic gear device 1 shown in Figures 1, 2, and 3 according to the embodiment, in order to facilitate understanding of directions, the direction perpendicular to the plane of the paper in Figure 1 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 axis 2o of the stator 21, and perpendicular to the circumferential direction C will be referred to as the radial direction R.

[0012] 1, 2, and 3 according to an embodiment of the present invention, a power transmission 100 transmits the driving force of a motor 2 to an external device. The power transmission 100 includes, for example, a magnetic gear device 1 and a motor 2.

[0013] The power transmission device 100 according to the first embodiment amplifies the torque of the rotor 22 of the motor 2, which is the input, at an output shaft (not shown) 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 stator 21 and a rotor 22 rotatable relative to the stator in a circumferential direction C. The motor 2 is an electric motor that converts electrical energy supplied from a power source into mechanical energy (energy that rotates the rotor 22 in the circumferential direction C). The motor 2 according to this embodiment is an outer rotor type in which the rotor 22 is disposed outside the stator 21 in the radial direction R.

[0015] The stator 21 is a part that generates a force for rotating the rotor 22 in the circumferential direction C. The stator 21 includes a yoke 211 formed in an annular shape, teeth 212 that protrude inward in the radial direction R from the inner circumferential surface of the yoke 211, coils 213 wound around the teeth 212, and insulators 214 that electrically insulate the teeth 212 and the coils 213 from each other.

[0016] In the stator 21 according to this embodiment, the yoke 211 and the teeth 212 are formed by punching out flat plate-shaped members made of a magnetic material (magnetic substance) such as an electromagnetic steel plate, and stacking multiple members in the axial direction A. In other words, the yoke 211 and the teeth 212 are made of a magnetic material (magnetic substance).

[0017] The coil 213 is electrically connected to, for example, a power supply. When the motor 2 is driven, a voltage is applied from the power supply to the coil 213, which generates a magnetic field in the coil 213 that changes over time. The interaction between this magnetic field and the magnetic force of the rotor magnet 221 causes the rotor 22 to rotate in the circumferential direction C relative to the stator 21.

[0018] Next, the rotor 22 will be described. The rotor 22 is disposed rotatably relative to the stator 21, on the outer side of the stator 21 in the radial direction R. The rotor 22 has a plurality of rotor magnets 221 (three in this embodiment). The rotor magnet 221 is, for example, ring-shaped, and has a plurality of magnetic poles (six poles in this embodiment) formed integrally. The rotor magnet 221 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 2 are integrated.

[0019] When the motor 2 having the above configuration is driven, the rotor 22 rotates in the circumferential direction C around the axis 2o relative to the stator 21.

[0020] The magnetic gear device 1 includes a first magnet 11, a second magnet 12, a first pole piece 13, and 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 driving side rotates about the axis 2o, 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 about the axis 2o. 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. The first space S1 may be filled with a non-magnetic material, such as a resin sliding material, as long as it allows the first magnet 11 and the pole piece 13 to rotate in a vacuum state or in the presence of a fluid such as air, water, or oil.

[0021] The first magnet 11 is provided so as to be rotatable about the axis 2o 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. The first magnet 11 is provided so as to be rotatable about the axis 2o 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 so as to be rotatable about the axis 2o in a non-contact state with the first pole piece 13.

[0022] 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, and therefore the number of pole pairs of the first magnet 11 is 14.

[0023] 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 2o.

[0024] 1, 2, and 3, the first magnet 11 is formed in a ring shape and has a downward side surface 11a and an upward side surface 11b. The first magnet 11 also 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, 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.

[0025] 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.

[0026] The first magnet 11 is formed by magnetizing the above-mentioned rare earth iron-based magnet to be magnetized 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.

[0027] Furthermore, in response to the miniaturization and high-resolution of devices (e.g., magnetic encoders) used, if the permanent magnet to be magnetized is composed of a rare-earth magnet with high magnetic properties (e.g., a Nd bonded magnet), the conventional pulse current coil current method requires a larger current to be passed, which can lead to problems such as larger and more expensive magnetization devices.In contrast, the first magnet 11 shown in this embodiment is formed from the object to be magnetized by heating the object to be magnetized using a heating unit and lowering the temperature from a temperature above the Curie point of the magnetic powder that makes up the object to be magnetized to a temperature below the Curie point, while continuing to generate a magnetic field using the permanent magnet in the field magnet unit, thereby performing multi-pole magnetization (see, for example, JP 2021-93521 A).

[0028] 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). Note that the pitch of the first magnetic poles 111 is measured on the outer periphery of the first magnet 11.

[0029] The second magnet 12 is rotatable about the axis 2o 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 2o 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 integrally formed 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 first pole piece 13 to rotate when in a vacuum state or when a fluid such as air, water, or oil is present.

[0030] 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).

[0031] 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 modulation pieces 131 of the first pole piece 13 is 29. Therefore, when the second magnet 12 on the inside in the radial direction R is used as the input, the first magnet 11 on the outside 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

[0032] 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

[0033] In the power transmission device 100 according to this embodiment, when the motor 2 is driven, the rotor 22 rotates around the axis 2o relative to the stator 21. Accompanying this rotation, the second back yoke 122 and the second magnet 12 fixed to the rotor 22 rotate together with the rotor 22 in the circumferential direction C. 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 outside 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, 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).

[0034] The output shaft (not shown) is disposed, for example, on the outside of the first back yoke 112 of the first magnet 11 in the radial direction R, and the torque of the first magnet 11 is output to the outside by a drive transmission mechanism (not shown). The drive transmission mechanism is constituted, for example, by a worm and a worm wheel.

[0035] 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.

[0036] As described above, the power transmission device 100 according to this embodiment includes the motor 2 having the stator 21 and the rotor 22 rotatably mounted relative to the stator 21, and the magnetic gear device 1 to which the driving force of the motor 2 is directly transmitted. The magnetic gear device 1 includes at least a first magnet 11 having a plurality of first magnetic poles 111 arranged in the circumferential direction C, a second magnet 12 having a plurality of second magnetic poles 121 arranged in the circumferential direction C, and a pole piece 13 positioned between the first magnet 11 and the second magnet 12 and magnetically connecting the first magnet 11 and the second magnet 12. At least one of the first magnet and the second magnet is ring-shaped, and the magnetic gear device 1 is a harmonic magnetic gear device. This eliminates the need to connect multiple magnets to form a link-shaped magnet, thereby simplifying the structure. Furthermore, the power transmission device 100 includes the motor 2, which is an input device, and the magnetic gear device 1 to which the driving force of the motor 2 is directly transmitted, and the magnetic gear device 1 is a harmonic magnetic gear device. More specifically, this magnetic gear device 1 is a harmonic magnetic gear device in which one of the ring-shaped first magnets 11 and the ring-shaped second magnets 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 the first magnetic poles 111 of the multiple first magnets 11 are magnetically coupled to the second magnetic poles 121 of the multiple second magnets 12 via a first pole piece 13 in the radial direction R. Therefore, compared to a magnetic gear device (e.g., JP 2011-196451 A) in which the first magnets and the second magnets are arranged so that a portion of the outer circumferential surface of the ring-shaped first magnet and a portion of the outer circumferential surface of the ring-shaped second magnet overlap in the axial direction, the magnetic gear device 1 according to this embodiment can magnetically couple the first magnetic poles 111 and the second magnetic poles 121 around the entire circumference of the axis 2o, thereby increasing the torque density and enabling increased torque.

[0037] 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.

[0038] Furthermore, the power transmission device 100 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, so that the magnetic gear device 1 can be easily retrofitted to the motor 2.

[0039] Furthermore, the rotor magnet 221 according to this embodiment is formed as a single ring by magnetizing a magnetic body, similar to the first magnet 11. Therefore, the rotor 22 according to this embodiment can be manufactured more easily by reducing the assembly work compared to, for example, a motor including a ring-shaped rotor magnet formed by connecting a plurality of individually formed magnets.

[0040] 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 torque (output torque) of the output shaft connected to the first magnet 11 of the magnetic gear device 1 to be greater than the torque (input torque) of the rotor 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.

[0041] 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.

[0042] 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.

[0043] In the power transmission device 100 according to this embodiment, the second magnet 12 is integrally formed with a plurality of second magnetic poles 121. This allows for a smaller and lighter magnetic gear device compared to a magnetic gear device that includes a second magnet formed by connecting individually formed magnets in the circumferential direction C.

[0044] In the power transmission device 100 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.

[0045] In the power transmission device 100 according to this embodiment, the second magnet 12 is disposed on the inside of the first magnet 11 in the radial direction R. The motor 2, which serves as the input device, is disposed on the inside of the second magnet 12 in the radial direction R. Furthermore, the output shaft is disposed on the outside of the first magnet 11 in the radial direction R.

[0046] 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 outside in the radial direction R is non-fixed, and the second magnet 12 arranged on the inside in the radial direction R is non-fixed and rotates together with the rotor 22. However, the magnetic gear device 1 according to the present embodiment is not limited to this. For example, as shown in Table 1, it is also possible for one of the first magnet 11, the second magnet 12, and the first pole piece 13 to be fixed and the remaining two to be non-fixed. Furthermore, it is also possible for one of the first magnet 11 and the second magnet 12 to be arranged on the inside in the radial direction R, and the other to be arranged on the outside in the radial direction R.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] Furthermore, in the motor 2 according to the above embodiment, the rotor magnet 221 has been described as having six poles. However, the number of magnetic poles of the rotor magnet according to this embodiment is not limited to this and can be set to any number.

[0051] 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.

[0052] Furthermore, in the magnetic gear device 1 according to the embodiment described above, the input shaft and output shaft can be interchanged. In this case, torque decreases, but speed can be improved. Furthermore, when the second magnet 12 arranged on the inside in the radial direction R is used as the input, the first magnet 11 arranged on the outside in the radial direction R is used as the output, and the first pole piece 13 is fixed, the reduction ratio X3 can be calculated as follows: X3 = 11M ÷ 12M = 26 ÷ 3 = 8.67

[0053] 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

[0054] 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 inside in the radial direction R and the second magnet 12 on the outside in the radial direction R, with the first magnet 11 side serving as the input shaft and the second magnet 12 side serving as the output shaft, and the first pole piece 13 being fixed, the speed increase ratio X5 can be calculated as follows: X5 = 11M ÷ 12M = 26 ÷ 3 = 8.67

[0055] 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

[0056] [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 a power transmission device 100A including 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 their description will be omitted. Furthermore, a motor 2 similar to that in the power transmission device 100 according to the first embodiment is arranged on the inside in the radial direction R of the magnetic gear device 1A.

[0057] The magnetic gear device 1A according to this modification has a first magnet 11, a second magnet 12, and a first pole piece 13.

[0058] In the magnetic gear device 1A, the first magnet 11 is disposed inside the second magnet 12 in the radial direction R, and the inner circumferential surface of the first back yoke 112 is fixed to the outer circumferential surface of the rotor 22. The first magnet 11 according to this modification is disposed on the input side (drive side) of the second magnet 12.

[0059] In the magnetic gear device 1A, the second magnet 12 is disposed on the outside of the first magnet 11 in the radial direction R, and the second back yoke 122 is connected to the output shaft via an intermediate transmission mechanism. The second magnet 12 according to this modification is disposed on the output side (driven side) of the first magnet 11.

[0060] In the power transmission device according to this modification, when the motor 2 is driven, the rotor 22 rotates around the axis 2o relative to the stator 21. Accompanying this rotation, the first back yoke 112 and the first magnet 11 fixed to the rotor 22 rotate together with the rotor 22 in the circumferential direction C. The change in magnetic flux of the first magnetic pole 111 in 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 connected to the driven side. In this case, in the magnetic gear device 1A according to this modification, the number of second magnetic poles 121 of the second magnet 12 arranged outside 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 rotational 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).

[0061] As described above, in the magnetic gear device 1A according to this modification, the first magnet 11 is arranged inside 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 modification can increase the speed of the output shaft (rotational speed on the output side) arranged outside the radial direction R of the magnetic gear device 1A more than the rotational speed of the rotor 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.

[0062] In the magnetic gear device 1A according to this modification, the first magnet 11 is disposed inside the second magnet 12 in the radial direction R.

[0063] [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 description thereof will be omitted. Furthermore, although not shown, the rotor 22 of the motor 2, similar to that of the power transmission device 100 according to the first embodiment, is fixed to the inner circumferential surface of the second magnet 12 in the radial direction R.

[0064] The magnetic gear device 1B of this modified example 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.

[0065] The outer peripheral surface of the output shaft is fixed to the inner peripheral surface of the first magnet 11 in the radial direction R. In other words, the first magnet 11 according to this modification is disposed on the output side (driven side) relative to the second magnet 12.

[0066] 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.

[0067] Furthermore, in the magnetic gear device 1B according to this modification, 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.

[0068] [Third Modification of First Embodiment] Fig. 6 is a cross-sectional view of a power transmission device 100C equipped with a magnetic gear device 1C according to a third modification of the first 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 third modification of the first embodiment, the same components as those in the magnetic gear device 1 according to the first embodiment are assigned the same reference numerals and their description will be omitted. 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.

[0069] In explaining the power transmission device 100C equipped with the magnetic gear device 1C shown in Figures 6, 7-1, and 7-2 relating to this modified example, to make it easier to understand the directions, the direction in which the second shaft 17, which is the output shaft, extends will be called 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 called the circumferential direction C, and the direction included in a plane perpendicular to the axial direction A, passing through the axis 2o, and perpendicular to the circumferential direction C will be called the radial direction R.

[0070] 6, 7-1, and 7-2, a power transmission (transmission) 100C according to this modification transmits the torque of the rotor 22 of the motor 2, which is the input device, to the second shaft 17, which is the output shaft. In the power transmission 100C according to this modification, the motor 2 and the magnetic gear device 1C are arranged so that the axis 2o of the stator 21 and rotor 22 of the motor 2, which is the input, coincides with the axis 2o of the second shaft 17, which is the output shaft. This power transmission 100C includes, for example, the magnetic gear device 1C and the motor 2.

[0071] A power transmission device 100C according to the third modification of the first embodiment increases the rotational speed of the rotor 22 of the motor 2, which is the input, at the second shaft 17, which is the output shaft, and outputs the increased rotational speed. The power transmission device 100C is housed in a frame (not shown), for example.

[0072] When the motor 2 having the above configuration is driven, the rotor 22 rotates around the axis 2o relative to the stator 21, and as a result of this rotation, the first back yoke 112 and the first magnet 11 fixed to the rotor 22 rotate in the circumferential direction C together with the rotor 22.

[0073] 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 modification, 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. More specifically, the first magnetic gear mechanism 1α is arranged on the input side, and the second magnetic gear mechanism 1β is arranged on the output side.

[0074] The first magnetic gear mechanism 1α is disposed on one side (input side) in the axial direction A where the motor 2 is disposed. The second magnetic gear mechanism 1β is disposed on the other side (output side) in the axial direction A where the second shaft 17, which is the output shaft, is disposed.

[0075] The first magnet 11 is provided in the magnetic gear device 1C so as to be rotatable about the axis 2o relative to the frame and the first pole piece 13. The first magnet 11 has a plurality of (e.g., 28) 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 2o without contacting the first pole piece 13.

[0076] 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.

[0077] 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 1C according to this modified example, the first magnet 11 and the second magnet 12 are arranged so as to be rotatable about a common axis 2o.

[0078] The first magnet 11 has a plurality of (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. The plurality of first magnetic poles 111 are arranged such that north poles and south poles alternate in the circumferential direction C. The first magnet 11 is also provided with a first back yoke 112 on the inside of the first magnetic poles 111 in the radial direction R. 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 when a fluid such as air, water, or oil is present.

[0079] The second magnet 12 is provided rotatably about the axis 2o 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 2o 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 outside of the second magnetic poles 121 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 first pole piece 13 to rotate when in a vacuum state or when a fluid such as air, water, or oil is present.

[0080] 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).

[0081] In the magnetic gear mechanism 1α according to this modification, the number of pole pairs 11M of the first magnet 11 is 26, the number of pole pairs 12M of the second magnet 12 is 3, and the number of modulation pieces 131 of the first pole piece 13 is 29. Therefore, when the second magnet 12 on the outside in the radial direction R is used as the output, the first magnet 11 on the inside in the radial direction R is used as the input, and the first pole piece 13 is fixed, the speed increase ratio X1 can be calculated as follows: X1 = 11M ÷ 12M = 26 ÷ 3 = 8.67

[0082] Alternatively, in the magnetic gear mechanism 1α, if the second magnet 12 is the output, the first pole piece 13 is the input, and the first magnet 11 is fixed, the speed increase ratio X2 can be calculated as follows: X2 = 13M ÷ 12M = 29 ÷ 3 = 9.67

[0083] 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.

[0084] The rotor 22 of the motor 2 is fixed to the inner circumferential surface of the first back yoke 112 of the first magnet 11 in the radial direction R. In other words, the motor 2 is disposed inside the first magnet 11 in the radial direction R.

[0085] 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.

[0086] The first magnetic gear mechanism 1α is a so-called flux modulation type magnetic gear (harmonic type magnetic gear device) in which, when the first back yoke 112 and first magnet 11 connected to the driving side rotate in the circumferential direction XC around the axis 2o, the change in magnetic flux of the multiple first magnetic poles 111 is modulated by the first pole piece 13 and transmitted to the second magnetic pole 121 of the second magnet 12 connected to the driven side, causing the second magnet 12 to rotate around the axis 2o.

[0087] In the first magnetic gear mechanism 1α, the number of second magnetic poles 121 of the second magnet 12 arranged on the output side is smaller than the number of first magnetic poles 111 of the first magnet 11 arranged on the input side. Therefore, when the first magnetic gear mechanism 1α is operated, the torque decreases but the rotational speed 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 the multiple first magnetic poles 111 are integrally formed in a ring shape. Therefore, compared to a magnetic gear device (such as the device described in JP 2022-150601 A) that includes a ring-shaped first magnet formed by connecting multiple individually formed magnets, the first magnetic gear mechanism 1α can narrow the pitch of the multiple first magnetic poles 111 in the circumferential direction C, thereby increasing the speed.

[0088] 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 first magnetic pole 111 and the gap between the first magnet 11 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 the rotation of the second magnet 12 in the circumferential direction C is stopped even when the first magnet 11 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.

[0089] The third magnet 14 is rotatable about the axis 17o of the second shaft 17 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.

[0090] The fourth magnet 15 is rotatable about the axis 17o of the second shaft 17 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 formed integrally 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, a fourth back yoke 152 is provided on the fourth magnet 15, for example, on the inner side in the radial direction R. In the magnetic gear mechanism 1β according to this modification, the third magnet 14 and the fourth magnet 15 are arranged to be rotatable about a 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 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.

[0091] 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).

[0092] The second shaft 17 is a so-called shaft and is formed, for example, cylindrically from a metal member. The second shaft 17 has an axis 17o, is formed integrally with the fourth back yoke 152, and is provided to be rotatable about the axis 17o relative to the frame. The second shaft 17 extends in the axial direction A relative to the fourth back yoke 152 and rotates in the circumferential direction C together with the fourth magnet 15 and the fourth back yoke 152. 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.

[0093] In the magnetic gear device 1C according to this modification, the second back yoke 122 and the third back yoke 142 are integrally formed. Furthermore, the second magnet 12 and the third magnet 14 are integrally formed. The second magnet 12 and the third magnet 14 according to this modification extend in the axial direction A.

[0094] In other words, in this magnetic gear device 1C, the second magnet 12 and the third magnet 14 are connected in the axial direction A, and the third magnet 14 rotates together with the second magnet 12 in the circumferential direction C. 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 one side in the axial direction A and the third magnet 14 is formed on the other side in the axial direction A. As a result, an unmagnetized intermediate portion IM1 is formed between the second magnet 12 and the third magnet 14 in the axial direction A.

[0095] In addition, in the axial direction A of this magnetic gear device 1C, the first magnet 11 and the fourth magnet 15 are arranged facing each other with a fifth space S5 interposed therebetween so as not to be affected by each other's magnetic forces.

[0096] 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.

[0097] 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 .

[0098] The second magnetic gear mechanism 1β is a so-called flux modulation type magnetic gear (harmonic type magnetic gear device) in which, when the third magnet 14 formed integrally with the second magnet 12 rotates together with the second magnet 12 in the circumferential direction XC around the axis 17o, the change in magnetic flux of the multiple third magnetic poles 141 is modulated by the second pole piece 16 and transmitted to the fourth magnetic pole 151 of the fourth magnet 15 connected to the driven side, causing the fourth magnet 15 to rotate in the circumferential direction C around the axis 17o.

[0099] In the second magnetic gear mechanism 1β, the number of fourth magnetic poles 151 of the fourth magnet 15 arranged on the output side is fewer than the number of third magnetic poles 141 of the third magnet 14 arranged on the input side. Therefore, when the second magnetic gear mechanism 1β is operated, torque decreases, but the rotational speed can be increased. In other words, the magnetic gear device 1C according to this modification can increase the rotational speed 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 (e.g., the device described in JP 2022-150601 A), the second magnetic gear mechanism 1β can increase speed because the pitch of the multiple third magnetic poles 141 in the circumferential direction C can be narrowed.

[0100] 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 third magnetic pole 141 and the gap between the third magnet 14 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 the rotation of the fourth magnet 15 in the circumferential direction C is stopped even when the third magnet 14 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.

[0101] In the first magnetic gear mechanism 1α according to this modification, the number of second magnetic poles 121 of the second magnet 12 located on the output side is 6, and the number of second magnetic poles 121 of the first magnet 11 located on the input side is 52. Therefore, the speed increase ratio X1 of the first magnetic gear mechanism 1α is calculated as follows: X1 = (52 ÷ 2) / (6 ÷ 2) = 8.67

[0102] In the second magnetic gear mechanism 1β according to this modification, the number of fourth magnetic poles 151 of the fourth magnet 15 located on the output side is six, and the number of third magnetic poles 141 of the third magnet 14 located on the input side is 52. Therefore, the speed increase ratio X2 of the second magnetic gear mechanism 1β is calculated as follows: X2 = (52 ÷ 2) / (6 ÷ 2) = 8.67

[0103] Therefore, the reduction ratio of the magnetic gear device 1C according to this modified example is calculated as follows: 8.67×8.67=75.2

[0104] As described above, the magnetic gear device 1C according to this modified example has the following configuration: The magnetic gear device 1C includes a ring-shaped first magnet 11 having a plurality of first magnetic poles 111 arranged in the circumferential direction C, a ring-shaped second magnet 12 having a plurality of second magnetic poles 121 arranged in the circumferential direction C, a first pole piece 13 located between the first magnet 11 and the second magnet 12 in the radial direction R and magnetically connecting the first magnet 11 and the second magnet 12, a ring-shaped third magnet 14 having a plurality of third magnetic poles 141 arranged in the circumferential direction C, a ring-shaped fourth magnet 15 having a plurality of fourth magnetic poles 151 arranged in the circumferential direction C, and a second pole piece 16 located between the third magnet 14 and the fourth magnet 15 in the radial direction R and magnetically connecting the third magnet 14 and the fourth magnet 15. Furthermore, in the magnetic gear device 1C, the second magnet 12 and the third magnet 14 are connected in the axial direction A, 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, 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 first magnets 11 to 15 is ring-shaped. Therefore, in the magnetic gear device 1C according to this modification, the rotational speed of the second shaft 17, which is the output shaft (rotational speed of the output side), can be increased more than the rotational speed of the rotor 22 of the motor 2 (rotational speed of the input side). Furthermore, in the magnetic gear device 1C of this modified example, 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 modified example 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.

[0105] In the magnetic gear device 1C according to this modification, the first magnet 11 has a plurality of first magnetic poles 111 integrally formed, and the third magnet 14 has a plurality of third magnetic poles 141 integrally formed. This allows for a smaller and lighter magnetic gear device compared to a magnetic gear device including a ring-shaped magnet formed by connecting individually formed magnets in the circumferential direction C. Furthermore, because the magnetic gear device 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.

[0106] Because the magnetic gear device 1C of this modified example 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 those in the ocean or aerospace, 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 in home appliances, cooling pumps and cooling fans in air conditioners, etc.

[0107] In the magnetic gear device 1C according to this modification, the second magnet 12 and the third magnet 14 are integrally formed. Therefore, compared to a magnetic gear device in which the second magnet 12 and the third magnet 14 are formed separately, the magnetic gear device 1C according to this modification can improve workability during assembly by reducing the number of parts.

[0108] In the magnetic gear device 1C according to this modified example, 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.

[0109] Although the magnetic gear device 1C described above has the second magnet 12 and the third magnet 14 formed integrally, the magnetic gear device 1C 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 IM1, and the second magnet 12 and the third magnet 14 may be connected in the axial direction A via the connecting portion.

[0110] Furthermore, in the magnetic gear device 1C described above, the input and output may be arranged in reverse. In this case, the rotational speed (in the circumferential direction C of the output shaft) on the output side decreases, but the torque can be increased.

[0111] Furthermore, in the first magnetic gear mechanism 1α of 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 1 according to this embodiment is not limited to this. For example, as shown in Table 2, the input side, output side, and fixing points can be changed as appropriate.

[0112] In the above-described modified example, the magnets 11, 12, 14, and 15 are 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, but only need to be able to connect (fix) the magnets 11, 12, 14, and 15 to other components.

[0113] In the magnetic gear device 1C according to the above-described modified example, 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 modified example is not limited to this and can be set to any number. The same applies to the third magnet 14.

[0114] Furthermore, in the magnetic gear device 1C according to the above-described modified example, the second magnet 12 has been described as having six second magnetic poles 121 (three pole pairs). However, the number of second magnetic poles 121 of the second magnet 12 according to this modified example is not limited to this and can be set to any number. The same applies to the fourth magnet 15.

[0115] In the magnetic gear device 1C according to the above-described modified example, 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 this modified example 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. The same applies to the second pole piece 16.

[0116] Furthermore, in the magnetic gear device 1C according to the above-described modified example, for example, the positions of the first magnet 11 and the second magnet 12 in the radial direction R can be interchanged, and the positions of the third magnet 14 and the fourth magnet 15 in the radial direction R can also be interchanged. In this case, the speed decreases, but the torque can be improved. In this case, if the first magnet 11 is the input, the second magnet 12 is the output, and the first pole piece 13 is fixed, the reduction ratio X3 can be calculated as follows: X3 = 11M ÷ 12M = 26 ÷ 3 = 8.67

[0117] 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, the reduction ratio X4 can be calculated as follows: X4 = 13M ÷ 12M = 29 ÷ 3 = 9.67

[0118] Furthermore, for example, in the magnetic gear mechanism 1α according to the above-described modified example, 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 speed increase ratio X5 can be calculated as follows: X5 = 11M ÷ 12M = 26 ÷ 3 = 8.67

[0119] 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

[0120] In the magnetic gear device 1C according to the above-described modified example, 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 modified example 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.

[0121] Furthermore, in the magnetic gear device 1C according to the above-described modified example, two-stage magnetic gear mechanisms 1α and 1β are arranged in the axial direction A. However, the magnetic gear device 1C according to this modified example 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.

[0122] [Fourth Modification of First Embodiment] Next, a magnetic gear device 1D according to a fourth modification of the first 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 fourth modification of the first 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 fourth modification of the first embodiment, the same components as those in the magnetic gear device 1C according to the third modification of the first embodiment are denoted by the same reference numerals and their description will be omitted. 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.

[0123] This power transmission device 100D includes, for example, a magnetic gear device 1D and a motor 2.

[0124] The magnetic gear device 1D includes a first magnetic gear mechanism 1α and a second magnetic gear mechanism 1β. In addition, 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.

[0125] The first magnetic gear mechanism 1α is composed of a first magnet 11, a second magnet 12, and a first pole piece 13.

[0126] 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.

[0127] 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 inner circumferential surface of the second back yoke 122 is fixed to the outer circumferential surface of the rotor 22. In other words, the second magnet 12 according to this modification is disposed on the input side (drive side) of the first magnet 11.

[0128] In the first magnetic gear mechanism 1α of the magnetic gear device 1D of this modified example, the number of first magnetic poles 111 of the first magnet 11 arranged on the output side is greater than the number of second magnetic poles 121 of the second magnet 12 arranged on the input side, so when the first magnetic gear mechanism 1α is operated, the rotational speed in the circumferential direction C decreases, but the torque can be increased.

[0129] The second magnetic gear mechanism 1β is composed of a third magnet 14, a fourth magnet 15, and a second pole piece 16.

[0130] 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 132 is disposed on the inside of the third magnet 14 in the radial direction R. 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 132 is formed integrally with the second shaft 17. In other words, the third back yoke 132 is connected to the second shaft 17.

[0131] 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.

[0132] In the power transmission device 100D according to this modification, when the motor 2 is driven, the rotor 22 rotates around the axis 2o relative to the stator 21. In response to this rotation, the second back yoke 122 and the second magnet 12, which are fixed to the outer peripheral surface of the rotor 22, rotate together with the rotor 22 in the circumferential direction C. The change in 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 also rotates in the circumferential direction C. Since the first magnet 11 and the fourth magnet 15 are integrally formed, the fourth magnet 15 also rotates in the circumferential direction C as the first magnet 11 rotates in the circumferential direction C. The change in 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.

[0133] In the second magnetic gear mechanism 1β of the magnetic gear device 1D according to this modification, the number of third magnetic poles 141 of the third magnet 14 located on the output side is greater than the number of fourth magnetic poles 151 of the fourth magnet 15 located on the input side, so when the second magnetic gear mechanism 1β is operated, the rotation speed in the circumferential direction C decreases but the torque can be increased. In other words, the magnetic gear device 1D according to this modification can increase the torque by using the two-stage magnetic gear mechanisms 1α and 1β.

[0134] 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 third modification of the first embodiment.

[0135] 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.

[0136] 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. For example, as shown in Table 3, the input side, output side, and fixing points can be changed as appropriate.

[0137] [Fifth Modification of First Embodiment] Next, a magnetic gear device 1E according to a fifth modification of the first embodiment will be described with reference to Figs. 10 and 11. Fig. 10 is a plan view of a power transmission device 100E including the magnetic gear device 1E according to the fifth modification of the first embodiment. Fig. 11 is a perspective view of the magnetic gear device 1E shown in Fig. 10. Note that in the configuration of the power transmission device 100E according to the fifth modification of the first embodiment, the same components as those in the power transmission device 100C according to the third modification of the first embodiment are denoted by the same reference numerals and their description will be omitted. Also, the motor 2 is omitted in Fig. 10-2.

[0138] A power transmission device 100E according to this modification includes a motor 2 and a magnetic gear device 1E.

[0139] 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. The magnetic gear device 1E 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.

[0140] The first magnetic gear mechanism 1α is composed of a first magnet 11, a second magnet 12, and a first pole piece 13.

[0141] In the first magnetic gear mechanism 1α, the first magnet 11 is disposed on the inside of the second magnet 12 in the radial direction R. A first back yoke 112 is provided on the inside of the first magnet 11 in the radial direction R according to this modification, and the inner circumferential surface of the first back yoke 112 is fixed to the outer circumferential surface of the rotor 22. The first magnet 11 in this modification is disposed on the input side (drive side) of the second magnet 12.

[0142] In the first magnetic gear mechanism 1α, the second magnet 12 is disposed outside the first magnet 11 in the radial direction R. The second magnet 12 according to this modification does not have a back yoke. The second magnet 12 according to this modification is disposed on the output side (driven side) of the first magnet 11.

[0143] The second magnetic gear mechanism 1β is composed of a third magnet 14, a fourth magnet 15, and a second pole piece 16.

[0144] In the second magnetic gear mechanism 1β, the third magnet 14 is disposed inside the fourth magnet 15 in the radial direction R. Furthermore, the third magnet 14 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.

[0145] In the second magnetic gear mechanism 1β, the fourth magnet 15 is disposed radially outward of the third magnet 14. A fourth back yoke 152 is provided radially outward of the fourth magnet 15 according to this modification. An intermediate transmission mechanism (not shown) is disposed radially outward of the fourth back yoke 152, and the driving force of the fourth magnet 15 is transmitted to the output shaft via the intermediate transmission mechanism. The fourth magnet 15 according to this modification is disposed on the output side (driven side) relative to the third magnet 14. In the magnetic gear device 1E according to this modification, 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 2o.

[0146] Furthermore, in the power transmission device 100E 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 1E, 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 third magnet 14 is formed on the outside in the radial direction R, and the second magnet 12 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.

[0147] In the power transmission device 100E according to this modified example, when the motor 2 is driven, the rotor 22 rotates around the axis 2o relative to the stator 21. Accompanying this rotation, the first back yoke 112 and the first magnet 11, which are fixed to the outer peripheral surface of the rotor 22, rotate together with the rotor 22 in the circumferential direction C. The first pole piece 13 modulates the change in magnetic flux of the first magnetic pole 111 in the first magnet 11 and transmits it 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. Since the second magnet 12 and the third magnet 14 are integrally formed, the third magnet 14 also rotates in the circumferential direction C as the second magnet 12 rotates in the circumferential direction C. The second pole piece 16 modulates the change in magnetic flux of the third magnetic pole 141 in the third magnet 14 and transmits it to the fourth magnetic pole 151 of the fourth magnet 15. Therefore, together with the rotation of the third magnet 14 in the circumferential direction C, the fourth magnet 15 also rotates in the circumferential direction C. Then, an output shaft (not shown) connected to the fourth back yoke 152 of the fourth magnet 15 via an intermediate output mechanism (not shown) rotates together with the rotation of the fourth magnet 15 in the circumferential direction C.

[0148] A power transmission device 100E according to this modified example has the following configuration: The power transmission device 100E includes a ring-shaped first magnet 11 having a plurality of first magnetic poles 111 arranged in the circumferential direction C, a ring-shaped second magnet 12 having a plurality of second magnetic poles 121 arranged in the circumferential direction C, a first pole piece 13 located between the first magnet 11 and the second magnet 12 in the radial direction R and magnetically connecting the first magnet 11 and the second magnet 12, a ring-shaped third magnet 14 having a plurality of third magnetic poles 141 arranged in the circumferential direction C, a ring-shaped fourth magnet 15 having a plurality of fourth magnetic poles 151 arranged in the circumferential direction C, and a second pole piece 16 located between the third magnet 14 and the fourth magnet 15 and magnetically connecting the third magnet 14 and the fourth magnet 15. Furthermore, the second magnet 12 and the third magnet 14 are connected in the radial direction R of this power transmission device 100E, 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 100E according to this modification can increase the rotational speed of the second shaft 17, which is the output shaft, (the rotational speed of the output side) more than the rotational speed of the rotor 22 of the motor 2 (the rotational speed of the input side). Furthermore, the power transmission device 100E according to this modification achieves the same functions and effects as the power transmission device 100C according to the third modification of the first embodiment.

[0149] In the power transmission device 100E of this modified example, the second magnet 12 and the third magnet 14 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 second magnet 12 and the third magnet 14 are formed separately.

[0150] In the power transmission device 100E according to this modification, 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.

[0151] Although the power transmission device 100E described above has the second magnet 12 and the third magnet 14 formed integrally, the power transmission device 100E 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, and the second magnet 12 and the third magnet 14 may be connected in the radial direction R via the connecting portion.

[0152] Furthermore, in the magnetic gear device 1E according to the above-described modified example, the two-stage magnetic gear mechanisms 1α and 1β are arranged in the radial direction R. However, the magnetic gear device 1E according to this modified example 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 also be configured by combining the magnetic gear device 1E according to the above-described modified example with the magnetic gear device 1D.

[0153] Furthermore, in the magnetic gear device 1E 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 1E according to this modified example is not limited to this. For example, as shown in Table 4, the input side, output side, and fixed locations can be changed as appropriate.

[0154] [Sixth Modification of First Embodiment] Next, a magnetic gear device 1F according to a sixth modification of the first embodiment will be described with reference to Figs. 12 and 13. Fig. 12 is a plan view of a power transmission device 100F including a magnetic gear device 1F according to the sixth modification of the first embodiment. Fig. 13 is a perspective view of the magnetic gear device 1F shown in Fig. 12. Note that in the configuration of the power transmission device 100F according to the sixth modification of the first embodiment, the same components as those in the power transmission device 100C according to the third modification of the first embodiment are denoted by the same reference numerals and their description will be omitted. Furthermore, the motor 2 is omitted from Fig. 13.

[0155] A power transmission device 100F according to this modification includes a motor 2 and a magnetic gear device 1F.

[0156] The magnetic gear device 1F includes a first magnetic gear mechanism 1α and a second magnetic gear mechanism 1β. In addition, the magnetic gear device 1F is 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.

[0157] The first magnetic gear mechanism 1α is composed of a first magnet 11, a second magnet 12, and a first pole piece 13.

[0158] In the first magnetic gear mechanism 1α, the first magnet 11 is disposed outside the second magnet 12 in the radial direction R. The first magnet 11 does not have a back yoke. The first magnet 11 according to this modification is disposed on the output side (driven side) of the second magnet 12.

[0159] 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. A second back yoke 122 is provided on the inside of the second magnet 12 in the radial direction R, and the inner circumferential surface of the second back yoke 122 is fixed to the outer circumferential surface of the rotor 22. In addition, the second magnet 12 according to this modification is disposed on the input side (drive side) of the first magnet 11.

[0160] The second magnetic gear mechanism 1β is composed of a third magnet 14, a fourth magnet 15, and a second pole piece 16.

[0161] In the second magnetic gear mechanism 1β, the third magnet 14 is disposed radially outward of the fourth magnet 15. A third back yoke 142 is provided radially outward of the third magnet 14 according to this modification. An intermediate transmission mechanism (not shown) is disposed radially outward of the third back yoke 142, and the driving force of the third magnet 14 is transmitted to the output shaft via the intermediate transmission mechanism. The third magnet 14 according to this modification is disposed on the output side (driven side) of the fourth magnet 15.

[0162] 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 modification does not have a back yoke. The fourth magnet 15 according to this modification is arranged on the input side (drive side) of the third magnet 14. In the magnetic gear device 1F according to this modification, the first magnet 11, the second magnet 12, the third magnet 14, and the fourth magnet 15 are arranged so as to be rotatable about a common axis 2o.

[0163] Furthermore, in the power transmission device 100F according to this modified example, the first magnet 11 and the fourth magnet 15 are integrally formed. In other words, in this magnetic gear device 1F, 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 fourth magnet 15 is formed on the outside in the radial direction R, and the first magnet 11 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.

[0164] In the power transmission device 100F according to this modified example, when the motor 2 is driven, the rotor 22 rotates around the axis 2o relative to the stator 21. In response to this rotation, the second back yoke 122 and the second magnet 12, which are fixed to the outer peripheral surface of the rotor 22, rotate together with the rotor 22 in the circumferential direction C. The change in 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 also rotates in the circumferential direction C. Since the first magnet 11 and the fourth magnet 15 are integrally formed, the fourth magnet 15 also rotates in the circumferential direction C as the first magnet 11 rotates in the circumferential direction C. The change in 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, together with the rotation of the fourth magnet 15 in the circumferential direction C, the third magnet 14 also rotates in the circumferential direction C. Then, an output shaft (not shown) connected to the third back yoke 142 of the third magnet 14 via an intermediate output mechanism (not shown) rotates together with the rotation of the third magnet 14 in the circumferential direction C.

[0165] A power transmission device 100F according to this modified example has the following configuration: The power transmission device 100F includes a ring-shaped first magnet 11 having a plurality of first magnetic poles 111 arranged in the circumferential direction C, a ring-shaped second magnet 12 having a plurality of second magnetic poles 121 arranged in the circumferential direction C, a first pole piece 13 located between the first magnet 11 and the second magnet 12 in the radial direction R and magnetically connecting the first magnet 11 and the second magnet 12, a ring-shaped third magnet 14 having a plurality of third magnetic poles 141 arranged in the circumferential direction C, a ring-shaped fourth magnet 15 having a plurality of fourth magnetic poles 151 arranged in the circumferential direction C, and a second pole piece 16 located between the third magnet 14 and the fourth magnet 15 and magnetically connecting the third magnet 14 and the fourth magnet 15. Furthermore, the first magnet 11 and the fourth magnet 15 are connected in the radial direction R of the power transmission device 100F according to this modification, 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. Therefore, the power transmission device 100F according to this modification can increase the torque of the output shaft (output side torque) more than the torque of the rotor 22 of the motor 2 (input side torque). Furthermore, the power transmission device 100F according to this modification achieves the same functions and effects as the power transmission device 100C according to the third modification of the first embodiment.

[0166] In the power transmission device 100F of this modified example, the first magnet 11 and the fourth magnet 15 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 first magnet 11 and the fourth magnet 15 are formed separately.

[0167] 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.

[0168] While the power transmission device 100F described above is one in which the first magnet 11 and the fourth magnet 15 are integrally formed, the power transmission device 100F according to this modification 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, connecting the first magnet 11 and the fourth magnet 15 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.

[0169] Furthermore, in the magnetic gear device 1F 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 1F according to this modified example is not limited to this. For example, as shown in Table 5, the input side, output side, and fixed locations can be changed as appropriate.

[0170] 14 is a plan view of a power transmission device 100G including a magnetic gear device 1 according to a second embodiment. In the configuration of the power transmission device 100G according to the second 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 descriptions thereof will be omitted.

[0171] This power transmission device 100G includes, for example, a magnetic gear device 1 and a motor 2G.

[0172] The motor 2G is an inner rotor type in which the rotor 22 is disposed inside the stator 21 in the radial direction R.

[0173] 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.

[0174] The power transmission device 100G according to this embodiment has the same functions and effects as the power transmission device 100 according to the first embodiment.

[0175] Furthermore, the power transmission device 100G of this embodiment can be constructed by attaching the magnetic gear device 1 to the inner 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 2G.

[0176] The power transmission device 100G described above includes the magnetic gear device 1 and the motor 2G. However, the power transmission device 100G 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.

[0177] 15 is a plan view of a power transmission device 100H including a magnetic gear device 1 according to a third embodiment. In the configuration of the power transmission device 100H according to the third 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 descriptions thereof will be omitted.

[0178] The power transmission device 100H includes, for example, a magnetic gear device 1 and a motor 2.

[0179] The motor 2 is an outer rotor type in which the rotor 22 is disposed outside the stator 21 in the radial direction R.

[0180] The second magnet 12 located on the inner side in the radial direction R faces the stator 21 in the radial direction R, and also functions as a rotor magnet for the rotor 22 in the motor 2 .

[0181] 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.

[0182] The power transmission device 100H according to this embodiment has the same functions and effects as the power transmission device 100 according to the first embodiment.

[0183] Furthermore, in the power transmission device 100H according to this embodiment, the second magnet 12 of the magnetic gear device 1 faces the stator 21 in the radial direction R, and also functions as a rotor magnet for the rotor 22 in the motor 2. 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.

[0184] The power transmission device 100H described above includes the magnetic gear device 1 and the motor 2. However, the power transmission device 100H 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.

[0185] 16 is a plan view of a power transmission device 100I including a magnetic gear device 1 according to a fourth embodiment. Note that in the configuration of the power transmission device 100I according to the fourth embodiment, the same components as those in the power transmission device 100 according to the first embodiment and the power transmission device 100G according to the second embodiment are assigned the same reference numerals and descriptions thereof will be omitted.

[0186] This power transmission device 100I includes, for example, a magnetic gear device 1 and a motor 2G.

[0187] The motor 2G is an inner rotor type in which the rotor 22 is disposed inside the stator 21 in the radial direction R.

[0188] 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.

[0189] The second magnet 12 located on the outer side in the radial direction R faces the stator 21 in the radial direction R, and also functions as a rotor magnet for the rotor 22 in the motor 2 .

[0190] 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.

[0191] The power transmission device 100I 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 100I according to this embodiment, the second magnet 12 of the magnetic gear device 1 faces the stator 21 in the radial direction R, and also functions as a rotor magnet for the rotor 22 in the motor 2. 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 in assembly.

[0192] The power transmission device 100I described above includes the magnetic gear device 1 and the motor 2G. However, the power transmission device 100I 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.

[0193] 17 is a plan view of a power transmission device 100J including a magnetic gear device 1 according to a fifth embodiment. In the configuration of the power transmission device 100J 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 descriptions thereof will be omitted.

[0194] The power transmission device 100J includes, for example, a magnetic gear device 1 and a motor 2.

[0195] The motor 2 is an outer rotor type in which the rotor 22 is disposed outside the stator 21 in the radial direction R.

[0196] In the power transmission device 100J, the rotor magnet 221 and the second magnet 12 are integrally formed.

[0197] Therefore, in this power transmission device 100J, the rotor magnet 221 and the second magnet 12 are connected in the radial direction R, and the second magnet 12 rotates together with the rotor magnet 221 in the circumferential direction C. To explain the rotor magnet 221 and the second magnet 12 more specifically, a ring-shaped magnetic body is used and magnetized as described above, so that the rotor magnet 221 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 221 and the number of second magnets 12 are different, but they may also be the same.

[0198] 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.

[0199] The power transmission device 100J 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 100J according to this embodiment, the rotor magnet 221 and the second magnet 12 are integrally formed, which improves the efficiency of assembly.

[0200] The power transmission device 100J described above includes the magnetic gear device 1 and the motor 2. However, the power transmission device 100J 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.

[0201] 18 is a plan view of a power transmission device 100K including a magnetic gear device 1 according to a sixth embodiment. Note that in the configuration of the power transmission device 100K according to the sixth embodiment, the same components as those in the power transmission device 100 according to the first embodiment and the same components as those in the power transmission device 100G according to the second embodiment are assigned the same reference numerals and descriptions thereof will be omitted.

[0202] This power transmission device 100K includes, for example, a magnetic gear device 1 and a motor 2G.

[0203] The motor 2G is an inner rotor type in which the rotor 22 is disposed inside the stator 21 in the radial direction R.

[0204] In the power transmission device 100K, the rotor magnet 221 and the second magnet 12 are integrally formed.

[0205] Therefore, in this power transmission device 100K, the rotor magnet 221 and the second magnet 12 are connected in the radial direction R, and the second magnet 12 rotates together with the rotor magnet 221 in the circumferential direction C. To explain the rotor magnet 221 and the second magnet 12 more specifically, a ring-shaped magnetic body is used and magnetized as described above, so that the rotor magnet 221 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 221 and the number of second magnets 12 are different, but they may also be the same.

[0206] 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.

[0207] The power transmission device 100K 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 100K according to this embodiment, the rotor magnet 221 and the second magnet 12 are integrally formed, which improves the efficiency of assembly.

[0208] The power transmission device 100K described above includes the magnetic gear device 1 and the motor 2G. However, the power transmission device 100K 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.

[0209] The above has been a description of the power transmission devices 100, 100A, 100C, 100D, 100E, 100F, 100G, 100H, 100I, 100J, and 100K according to the present invention based on the embodiments and modifications thereof. However, the present invention is not limited to the embodiments and modifications thereof, and various modifications are possible without departing from the spirit of the present invention. The present invention also includes configurations in which the components of the above-described embodiments and modifications are appropriately combined. Such various modifications without departing from the spirit of the present invention are also included within the technical scope of the present invention, and this is clear to those skilled in the art from the claims.

[0210] 1, 1A, 1B, 1C, 1D, 1E, 1F Magnetic gear device (harmonic type 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, 100C, 100D, 100E, 100F, 100G, 100H, 100I, 100J, 100K Power transmission device, A Axial direction, C Circumferential direction, R Radial direction

Claims

1. A power transmission device comprising: a motor having a stator and a rotor rotatable relative to the stator; and a magnetic gear device to which the driving force of the motor is directly transmitted, wherein the magnetic gear device 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, and a pole piece located between the first magnet and the second magnet and magnetically connecting the first magnet and the second magnet, wherein at least one of the first magnet and the second magnet is ring-shaped, and the magnetic gear device is a harmonic magnetic gear device.

2. A power transmission device as described in claim 1, wherein the rotor has a plurality of rotor magnets, the plurality of rotor magnets are arranged along the circumferential direction, and the rotor magnets are arranged so as to face either the first magnet or the second magnet in the radial direction.

3. A power transmission device according to claim 1, wherein 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.

4. A power transmission device according to claim 2, 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.

5. A power transmission device according to claim 2, 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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