The present disclosure relates to a magnetic geared rotary electric machine. Priority is claimed on Japanese Patent Application No. 2020-010264, filed Jan. 24, 2020, the content of which is incorporated herein by reference.
Patent Document 1 below discloses a magnetic geared rotary electric machine in which a low-speed rotor (first rotor), a high-speed rotor (second rotor), and a stator are coaxially rotatable relative to each other. When the magnetic geared rotary electric machine is used as, for example, a motor, the low-speed rotor which is an output shaft rotates at a predetermined reduction ratio due to a harmonic magnetic flux by rotating the high-speed rotor by an electromotive force of a coil provided in the stator.
In the magnetic geared rotary electric machine, the stator includes a stator core and a plurality of stator magnets provided on the inner peripheral side of the stator core. The stator core includes an annular back yoke and teeth protruding radially inward from the back yoke. The stator magnet is disposed on the inner peripheral side of the front end portions of the teeth.
Patent Document 1: Japanese Unexamined Patent Application, First Publication No. 2014-163431
Here, in the magnetic geared rotary electric machine, it is desirable to easily attach a coil made of a large diameter lead wire to the stator in order to generate a larger torque. Further, it is desired to further reduce a magnetic resistance of the stator with respect to a fundamental wave magnetic flux of the second rotor in order to efficiently operate the magnetic geared rotary electric machine.
The present disclosure has been made to solve the above-described problems and an object thereof is to provide a magnetic geared rotary electric machine capable of easily attaching a coil and reducing a magnetic resistance of a stator with respect to a fundamental wave magnetic flux of a second rotor.
In order to solve the above-described problems, a magnetic geared rotary electric machine according to the present disclosure includes: a casing; a stator which includes a stator core fixed to the casing and formed in an annular shape centered on an axis, a coil installed inside a slot of the stator core, and a plurality of stator magnets installed inside the stator core at intervals in a circumferential direction about the axis; a first rotor which includes a plurality of pole pieces provided inside the stator at intervals in the circumferential direction about the axis; and a second rotor which includes a rotor core provided inside the first rotor and a plurality of rotor magnets provided in the rotor core at intervals in the circumferential direction, wherein the stator core includes a back yoke surrounding the axis and a plurality of teeth formed on the back yoke at intervals in the circumferential direction, each of the plurality of teeth including a tooth body developing radially inward from the back yoke and a pair of tooth grasping portions protruding from both circumferential ends at a radially inner section of the tooth body, wherein the coil is installed inside the slot formed between the tooth bodies of the teeth adjacent to each other, and wherein the stator magnet is installed between the tooth grasping portions of the same teeth and between the tooth grasping portions of the different teeth adjacent to each other.
According to the present disclosure, it is possible to easily attach a coil and to reduce a magnetic resistance of a stator with respect to a fundamental wave magnetic flux of a second rotor.
Hereinafter, a magnetic geared rotary electric machine 100 according to a first embodiment of the present disclosure will be described with reference to
As shown in
As shown in
Each of the teeth 7T (portion indicated by the diagonal line) includes a tooth body 72 which is developed radially inward from the back yoke 71, a pair of tooth grasping portions 73 which is integrally formed with the radially inner end portion of the tooth body 72, and a claw portion 74. The tooth grasping portion 73 projects radially inward from both sides of the tooth body 72 in the circumferential direction. The front end portion (radially inner end portion) of the tooth grasping portion 73 is further provided with the claw portions 74 which are protruded from the tooth grasping portion 73 in the circumferential direction. That is, the claw portions 74 are protruded toward the inside of a slot S.
The plurality of coils C are attached to the radially outer portion of a plurality of tooth bodies 72. The coil C is formed by winding a copper wire or the like around the tooth body 72. In this embodiment, the coil C is wound around the tooth body 72 in a mode called distributed winding. In the distributed winding, the coil C is formed by winding a wire over the plurality of teeth 7T. In addition to the distributed winding, the coil C can be formed in a mode called centralized winding shown in
As shown in
The stator magnet 1B is a permanent magnet such as a ferrite magnet or a neodymium magnet. The poles (magnetization direction) facing the inner peripheral side are different between the stator magnets 1B adjacent to each other. More specifically, these stator magnets 1B are arranged according to the Halbach magnet arrangement. As shown in
This embodiment includes first slots S1 which each accommodates the coil C and the stator magnet 1B and second slots S2 which each accommodates only the stator magnet 1B. As an example, the first slots S1 and the second slots S2 are arranged in the circumferential direction. Since the dimension (width) of the first slot S1 in the circumferential direction is equal to that of the stator magnet 1B, the coil C and the stator magnet 1B can be provided inside the first slot S1. Accordingly, the molded coil C can be easily attached into the first slot S1. Additionally, it is also possible to adopt a configuration in which the plurality of second slots S2 are provided between the pair of first slots S1.
The wedge W is provided between the coil C and the stator magnet 1B inside the first slot S. The wedge W is a member made of a material having a specific magnetic permeability of 1 or more and is provided for the purpose of insulating between the coil C and the stator magnet 1B and preventing the coil C from falling off. The specific magnetic permeability of the wedge W is preferably 10 or less.
As shown in
As shown in
Next, an operation of the above-described magnetic geared rotary electric machine 100 will be described. When the magnetic geared rotary electric machine 100 is used as the electric motor, electric power is first supplied to the coil C from the outside. Accordingly, the coil C is excited. The second rotor 3 rotates around the axis Ac by the magnetic force of the coil C. Further, when the second rotor 3 rotates, the first rotor 2 rotates. The rotation speed of the first rotor 2 is decelerated under a reduction ratio based on the number of poles Ph of the first rotor 2 and the number of pole pairs Ns of the second rotor 3. Specifically, the reduction ratio G is G=Ph/Ns.
On the other hand, when the magnetic geared rotary electric machine 100 is used as the generator, a rotational force (torque) around the axis Ac is applied to the rotating shaft 6. Accordingly, the first rotor 2 and the second rotor 3 rotate by the rotation of the rotating shaft 6. An induced electromotive force is generated in the coil C as the first rotor 2 and the second rotor 3 rotate. By taking out this electric power to the outside, the magnetic geared rotary electric machine 100 can be used as the generator.
Here, in this embodiment, the tooth grasping portion 73 is configured to hold the stator magnet 1B on the radial inside of the coil C and on the radial inside of the tooth body 72, respectively. Since the stator magnet 1B is provided on the radial inside of the coil C, it is possible to increase the opening width of the slot S1 provided with the coil C. Therefore, it is possible to attach even the coil C made of a high voltage lead wire having a large diameter. Further, since the stator magnet 1B is provided on the radial inside of the tooth body 72, the tooth body 72 having a small magnetic resistance exists as a relatively wide area on the radial outside of the stator magnet 1B. Accordingly, the tooth grasping portion 73 holding the stator magnet 1B can guide the magnetic flux wave component from the second rotor 3 to the tooth body 72 having a small magnetic resistance. As a result, it is possible to largely reduce the magnetic resistance of the teeth 7T as a whole with respect to the fundamental wave magnetic flux of the second rotor 3 and to effectively use the magnetic energy generated by the rotor magnet 3B of the second rotor 3.
Furthermore, according to the above-described configuration, it is possible to more stably hold the stator magnets 1B by the claw portions 74. Further, since the claw portions 74 are provided to be widened from the tooth grasping portion 73, it is possible to reduce the magnetic resistance of the portion of the stator 1 facing the rotor magnet 3B.
Further, according to the above-described configuration, the stator magnets 1B are arranged in a Halbach magnet arrangement. Accordingly, it is possible to strengthen a specific directional component of the magnetic field strength generated by the stator magnet 1B. Thus, it is possible to enhance the magnetic performance of the stator magnet 1B and to improve the torque of the magnetic geared rotary electric machine 100.
In addition, according to the above-described configuration, the wedge W can prevent the coil C from falling off.
Although the embodiment of the present disclosure has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment and includes design changes and the like within a range not deviating from the gist of the present disclosure.
As shown in
Further, since the tooth grasping portion 73b has a wedge shape, the claw portion 74 is not necessary. Therefore, it is possible to reduce the clearance between the stator magnet 1B and the pole piece 2P. Accordingly, it is possible to effectively use the energy of the magnet. Further, since the stator magnet 1B is fitted into the opening portion of the slot S1 in a wedge shape, the stator magnet can have a role as a support member of the coil C. Further, since the tooth grasping portion 73b has a higher strength than that of the claw portion 74, it is possible to more reliably hold the stator magnet 1B.
Further, as shown in
The magnetic geared rotary electric machine 100 described in each embodiment can be summarized as follows, for example.
(1) The magnetic geared rotary electric machine 100 according to a first aspect includes: the casing 4; the stator 1 which includes the stator core 1A fixed to the casing 4 and formed in an annular shape centered on the axis Ac, the coil C installed inside the slot S of the stator core 1A, and the plurality of stator magnets 1B installed inside the stator core 1A at intervals in the circumferential direction about the axis; the first rotor 2 which includes the plurality of pole pieces 2P provided inside the stator 1 at intervals in the circumferential direction about the axis Ac; and the second rotor 3 which includes the rotor core 3A provided inside the first rotor 2 and the plurality of rotor magnets 3B provided in the rotor core 3A at intervals in the circumferential direction, wherein the stator core 1A includes the back yoke 71 surrounding the axis Ac and the teeth 7T formed on the back yoke 71 at intervals in the circumferential direction, each of the plurality of teeth 7T including the tooth body 72 developing radially inward from the back yoke 71 and the pair of tooth grasping portions 73 protruding from both circumferential ends at the radially inner section of the tooth body 72, the coil C is installed inside the slot S between the tooth bodies 72 of the teeth 7T adjacent to each other, and the stator magnet 1B is installed between the tooth grasping portions 73 of the same teeth 7T and between the tooth grasping portions 73 of the different teeth 7T adjacent to each other.
According to the above-described configuration, since the stator magnet is provided on the radial inside of the coil, it is possible to increase the opening width of the slot provided with the coil. Further, the tooth grasping portion holding the stator magnet can guide the magnetic flux wave component from the second rotor to the tooth body having a small magnetic resistance. As a result, it is possible to largely reduce the magnetic resistance of the teeth as a whole with respect to the fundamental wave magnetic flux of the second rotor.
(2) The magnetic geared rotary electric machine 100 according to a second aspect may further include: the claw portion 74 which is formed at the top end of the tooth grasping portion 73 so as to be protruded in the circumferential direction.
According to the above-described configuration, it is possible to more stably hold the stator magnet 1B by the claw portion 74.
(3) In the magnetic geared rotary electric machine 100 according to a third aspect, the tooth grasping portion 73 may be formed so that the circumferential width dimension of the tooth grasping portion is gradually increased from the radial outside to the radial inside.
According to the above-described configuration, since the tooth grasping portion 73 is formed so that the circumferential width dimension of the tooth grasping portion 73 is gradually increased as it forward radially inside, the space (slot S) between the tooth grasping portions 73 is a trapezoidal shape with the radial inside as the upper bottom. Accordingly, it is possible to more stably hold the stator magnet 1B. Further, since it is possible to increase the area of the tooth grasping portion 73 when viewed from the direction of the axis Ac, it is possible to ensure a larger magnetic path. Accordingly, it is possible to further reduce the magnetic resistance.
(4) In the magnetic geared rotary electric machine 100 according to a fourth aspect, the plurality of stator magnets may be arranged in a Halbach magnet arrangement.
According to the above-described configuration, the stator magnets 1B are arranged in the Halbach magnet arrangement. Accordingly, it is possible to strengthen a specific directional component of the magnetic field strength generated by the stator magnet 1B. Thus, it is possible to enhance the magnetic performance of the stator magnet 1B and to improve the torque of the magnetic geared rotary electric machine 100.
(5) The magnetic geared rotary electric machine 100 according to a fifth aspect may further include: the wedge W which is provided between the coil C and the stator magnet 1B.
According to the above-described configuration, it is possible to prevent the coil C from falling off by the wedge W.
(6) In the magnetic geared rotary electric machine 100 according to the sixth aspect, the teeth 7T further includes another tooth grasping portion 75 which is formed between the pair of tooth grasping portions 73 so as to be protruded radially inward from the tooth body 72 and the stator magnets 1B may be installed between the tooth grasping portions 73 and 75 of the same teeth 7T.
The present disclosure relates to a magnetic geared rotary electric machine. According to the present disclosure, it is possible to easily attach a coil and to reduce a magnetic resistance of a stator with respect to a fundamental wave magnetic flux of a second rotor.
100 Magnetic geared rotary electric machine
Number | Date | Country | Kind |
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2020-010264 | Jan 2020 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2021/000081 | 1/5/2021 | WO |