JP2021175284A - Motor device - Google Patents

Abstract

To provide a motor device that can output high torque and is compact and lightweight.SOLUTION: A motor device 2 includes a rotor 23, in which a plurality of permanent magnets 232 is arranged in an annular Halbach arrangement around a central axis C, a stator 22, which has a cylindrical-shaped portion 221, which is arranged to surround the rotor 23 in the outer radial direction of the rotor 23 and a plurality of windings 222, which is arranged at equal intervals along the circumferential direction in the outer radial direction of the cylindrical-shaped portion 221, and a container 21, which houses the stator 22. The windings 222 contain a superconducting material. A space between the cylindrical-shaped portion 221 and the container 21 is filled with a cooling liquid 24.SELECTED DRAWING: Figure 2

Description

The present invention relates to a motor device.

Conventionally, eco-friendly electric vehicles that do not emit exhaust gas have been developed. The electric vehicle uses the electric power stored in the storage battery to drive the motor device to rotate the wheels. For example, Patent Document 1 discloses a three-phase alternating current motor for a vehicle, which is driven by a current converted into a three-phase alternating current by an inverter. Vehicle motor devices are required to be able to output high torque, and are also required to be compact and lightweight.

JP-A-2019-146304

The present invention has been devised under the above circumstances, and an object of the present invention is to provide a motor device capable of outputting high torque and being compact and lightweight.

In order to solve the above problems, the following technical measures are taken in the present invention.

In the motor device provided by the present invention, a plurality of permanent magnets surround the rotor in an annular Halbach array around the central axis and the rotor outside the radial direction of the rotor. And a stator having a plurality of windings arranged at equal intervals along the circumferential direction on the outside of the cylindrical portion in the radial direction, and a container for accommodating the stator. The winding contains a superconducting material, and a coolant is filled between the cylindrical portion and the container.

In a preferred embodiment of the present invention, the winding is a coil in which a strip-shaped wire rod containing a superconductor material is wound in a double pancake shape, and the shape of the coil surface is a race track shape.

In a preferred embodiment of the present invention, the axial dimension of each winding, which is the extending direction of the central axis, and the axial dimension of each permanent magnet are 200 mm or less, and the winding. The number of is 15 or more.

In a preferred embodiment of the present invention, the container includes an outer container and an inner container, and the space surrounded by the outer container and the inner container has a higher degree of vacuum than the outside.

In a preferred embodiment of the present invention, the rotor further includes a rotor body to which the plurality of permanent magnets are fixed, and the rotor body and the cylindrical portion are made of a material containing a synthetic resin.

In a preferred embodiment of the invention, the stator further comprises a cylindrical portion and a back yoke arranged radially outside the plurality of windings.

According to the present invention, each winding of the stator contains a superconducting material and is cooled by a coolant filled between the cylindrical portion and the container. As a result, each winding is put into a superconducting state, and the electric resistance is remarkably lowered, so that a large current can flow. Therefore, since the stator can generate a large rotating magnetic field, the motor device can output a high torque. Further, the electric resistance of each winding is remarkably reduced, so that the generation of Joule heat is suppressed. In addition, each winding is strongly cooled by the coolant. Therefore, the motor device does not need to be provided with heat radiating fins or the like for cooling. As a result, the motor device can be made smaller and lighter. Further, according to the present invention, in the rotor, a plurality of permanent magnets are arranged in an annular Halbach array. Therefore, the rotor can concentrate the magnetic flux on the stator side to increase the magnetic field strength. As a result, the motor device can output a high torque. Further, since the rotor can suppress the magnetic flux generated on the side opposite to the stator, it is not necessary to provide the yoke on the side opposite to the stator. As a result, the motor device can be made smaller and lighter.

Other features and advantages of the present invention will become more apparent with the detailed description given below with reference to the accompanying drawings.

It is a schematic block diagram which shows the structure of the vehicle to which the motor device which concerns on 1st Embodiment is applied. It is sectional drawing of the cross section orthogonal to the central axis of the motor apparatus which concerns on 1st Embodiment. It is sectional drawing of the cross section along the central axis of the motor apparatus which concerns on 1st Embodiment.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.

<First Embodiment>
FIG. 1 is a schematic block diagram showing a configuration of a vehicle 1 to which the motor device according to the first embodiment is applied. The vehicle 1 is an electric vehicle driven by an electric motor. As shown in FIG. 1, the vehicle 1 includes a motor device 2, a coolant tank 3, a storage battery 4, and an inverter 5. Although the vehicle 1 has other configurations, the description is omitted in FIG.

The motor device 2 is a superconducting motor and generates a driving force for the vehicle 1. The motor device 2 transmits the rotation of the shaft 233, which will be described later, to the axle of the vehicle 1 by a gear or the like (not shown) to rotate the wheels. Details of the motor device 2 will be described later.

The coolant tank 3 replenishes the coolant inside the motor device 2. The coolant tank 3 is connected to the motor device 2 by a transfer tube 31. The transfer tube 31 is a thin vacuum-insulated tube that allows the coolant to flow from the coolant tank 3 to the motor device 2. When the coolant is first flowed by applying a little pressure, the transfer tube 31 is cooled by the coolant, and the coolant flows. In this embodiment, the coolant is liquid nitrogen. Nitrogen vaporized by cooling the motor device 2 is discharged to the outside of the vehicle 1 from a discharge valve (not shown) of the motor device 2 through a discharge pipe 32. The coolant tank 3 replenishes the motor device 2 with the liquid nitrogen reduced by vaporization via the transfer tube 31. When the amount of liquid nitrogen in the coolant tank 3 decreases, the liquid nitrogen is replenished in the coolant tank 3 from the liquid nitrogen tank lorry wheel or the liquid nitrogen supply facility. The coolant is not limited to liquid nitrogen, and may be any other liquid. The coolant may be any liquid that can cool the winding 222 of the motor device 2, which will be described later, to a predetermined temperature.

The storage battery 4 is a secondary battery that stores electric power for driving the motor device 2. In the present embodiment, the storage battery 4 is a lithium ion battery. The storage battery 4 is not limited to this, and may be another secondary battery. The inverter 5 converts the DC power input from the storage battery 4 into three-phase AC power and outputs it to each winding 222 of the motor device 2. A plurality of current limiters, each of which is connected in series to each winding 222, are provided between the inverter 5 and each winding 222 in order to prevent the occurrence of quenching, but detailed description thereof will be omitted. do.

Next, the details of the motor device 2 will be described.

2 and 3 are schematic views for explaining the motor device 2. FIG. 2 is a cross-sectional view of a cross section orthogonal to the central axis C of the motor device 2. FIG. 3 is a cross-sectional view of a cross section of the motor device 2 along the central axis C. It should be noted that each figure is simplified for easy understanding. Therefore, the dimensions and ratios of each part do not match the actual dimensions and ratios, and are appropriately enlarged or reduced. Further, in the following, for convenience of explanation, the direction parallel to the central axis C of the motor device 2 is defined as the "axial direction", the direction orthogonal to the central axis C is defined as the "diameter direction", and an arc centered on the central axis C is formed. The direction along the line is defined as the "circumferential direction".

The motor device 2 includes a container 21, a stator 22, and a rotor 23. The stator 22 is arranged so as to surround the rotor on the outer side in the radial direction of the rotor 23. The stator 22 acts as an armature to generate an armature magnetic field (rotating magnetic field). The rotor 23 becomes a field and generates a field magnetic field. The armature magnetic field generated by the stator 22 acts on the magnetic poles of the rotor 23 to generate torque that rotates the rotor 23 around the central axis C. The container 21 is arranged outside the stator 22 and houses the stator 22 and the rotor 23.

The rotor 23 becomes a field and generates a field magnetic field, and rotates around the central axis C in the circumferential direction. The rotor 23 includes a main body 231, a plurality of permanent magnets 232, and a shaft 233. The shaft 233 is rotatably supported by the bearing 26 with respect to the stator 22. The shaft 233 transmits the rotational force of the motor device 2 to the outside. The material of the shaft 233 is not limited.

The main body 231 is fixed to the shaft 233 and includes a cylindrical portion and a fixed portion. The cylindrical portion has a cylindrical shape extending in the axial direction, and a plurality of permanent magnets 232 are fixed to the cylindrical portion. As for the fixed portion, the cylindrical portion is fixed to the shaft 233. In the present embodiment, the main body 231 is made of synthetic resin, and the cylindrical portion and the fixed portion are integrally formed. The shape, material, and forming method of the main body 231 are not limited.

Each of the plurality of permanent magnets 232 is a permanent magnet and has a rectangular parallelepiped shape extending in the axial direction. In this embodiment, the axial dimension of each permanent magnet 232 is 200 mm. The dimensions are not limited. Each permanent magnet 232 includes, for example, a neodymium magnet and a ferrite magnet, and is not limited. The type of each permanent magnet 232 is appropriately determined in consideration of the required magnetic force and cost. Each permanent magnet 232 is embedded in a cylindrical portion of the main body 231. In the present embodiment, as shown in FIG. 2, 30 permanent magnets 232 are arranged at equal intervals along the circumferential direction in the cylindrical portion of the main body 231. The number of permanent magnets 232 is not limited.

The plurality of permanent magnets 232 are arranged in an annular Halbach array with the central axis C as the center. The Halbach array is a method of arranging magnets that maximizes the magnetic field strength in a specific direction by optimizing the direction of the magnetic poles. In FIG. 2, each permanent magnet 232 is provided with an arrow indicating the direction of the magnetic pole. The plurality of permanent magnets 232 concentrate the magnetic flux on the outer peripheral surface side of the cylindrical portion of the main body 231 and increase the magnetic field strength on the outer peripheral surface side. On the other hand, the magnetic flux generated on the inner peripheral surface side of the cylindrical portion of the main body 231 is small, and the magnetic field strength on the inner peripheral surface side is small. The direction of the magnetic poles of each permanent magnet 232 shown in FIG. 2 is only an example, and the direction of the magnetic poles of each permanent magnet 232 is not limited to that shown in FIG. As the magnetic field strength on the outer peripheral surface side of the cylindrical portion of the main body 231 increases, the action on the magnetic poles by the armature magnetic field (rotating magnetic field) generated by the stator 22 arranged outside the rotor 23 increases. , The motor device 2 can output a high torque. Further, since the magnetic flux generated on the inner peripheral surface side of the cylindrical portion of the main body 231 is suppressed, the rotor 23 does not need to be provided with a yoke inside the cylindrical portion of the main body 231 in the radial direction.

In the rotor 23, for example, each permanent magnet 232 magnetized in a predetermined direction is arranged at a predetermined position in a predetermined direction inside the mold, and a fluid synthetic resin material is placed in the mold. Is formed by injecting and curing. The method of forming the rotor 23 is not limited.

The stator 22 acts as an armature to generate an armature magnetic field. The stator 22 includes a cylindrical portion 221, a plurality of windings 222, and a back yoke 223.

The cylindrical portion 221 is a cylindrical component extending in the axial direction, and is arranged so as to surround the rotor 23 on the outer side in the radial direction of the rotor 23. In the present embodiment, the cylindrical portion 221 is made of a material containing a synthetic resin such as fiber reinforced plastics (FRP). The material of the cylindrical portion 221 is not limited. The radial thickness of the cylindrical portion 221 is preferably as thin as possible in order to bring the winding 222 and the permanent magnet 232 closer together. In the present embodiment, the radial thickness of the cylindrical portion 221 is set to about 2 mm in order to bring the winding 222 and the permanent magnet 232 closer to each other while maintaining the strength of the cylindrical portion 221. The dimensions are not limited. The cylindrical portion 221 is fixed to the inner bottom surface of the container 21, and an air gap 25 is provided between the inner peripheral surface of the cylindrical portion 221 and the outer peripheral surface of the cylindrical portion of the main body 231 of the rotor 23. The thickness of the air gap 25 (the distance between the inner peripheral surface of the cylindrical portion 221 and the outer peripheral surface of the cylindrical portion) is preferably as thin as possible in order to bring the winding 222 and the permanent magnet 232 close to each other. In the present embodiment, the thickness of the air gap 25 is set in order to reduce the distance between the winding 222 and the permanent magnet 232 while preventing contact between the inner peripheral surface of the cylindrical portion 221 and the outer peripheral surface of the cylindrical portion. It is about 3 mm. The dimensions are not limited.

Further, a space is also provided between the outer peripheral surface of the cylindrical portion 221 and the inner peripheral surface of the container 21. The cylindrical portion 221 includes a plurality of projecting portions 221a. Each protruding portion 221a protrudes in the radial direction from the outer peripheral surface of the cylindrical portion 221 and extends in the axial direction. The plurality of projecting portions 221a are arranged on the outer peripheral surface of the cylindrical portion 221 at equal intervals along the circumferential direction. Winding 222s are arranged between the protrusions 221a and the protrusions 221a, respectively. The cylindrical portion 221 does not have to include the protruding portion 221a.

An alternating current flows through each of the plurality of windings 222 to generate a rotating magnetic field. The plurality of windings 222 are arranged on the outer peripheral surface of the cylindrical portion 221 at equal intervals along the circumferential direction. In this embodiment, as shown in FIG. 2, 15 windings 222 are arranged. Three-phase alternating currents whose phases are shifted by 120 degrees are input to the three adjacent windings 222, respectively. Since the stator 22 includes five sets of the three windings 222, a total of 15 windings 222 are provided. The number of windings 222 included in the stator 22 is not limited to 15, and may be a multiple of 3. However, in the present embodiment, since the motor device 2 needs to output the torque for driving the vehicle 1, it is preferable that the number of windings 222 is large. Further, the larger the number of windings 222, the closer the arrangement of the windings 222 can be to the circumference, and the rotating magnetic field by the windings 222 is in the circumferential direction with respect to the magnetic poles of the permanent magnets 232 arranged in an annular Halbach array. Since it acts evenly in the above, the vibration of the entire motor device 2 can be suppressed. It is desirable that the number of windings 222 is at least 15 or more. On the other hand, as the number of windings 222 increases, the weight of the motor device 2 increases. Therefore, the number of windings 222 is appropriately set in consideration of the torque output and the weight.

Each winding 222 is a coil wound with a strip-shaped wire containing a superconductor material. The superconductor material is not limited, but in the present embodiment, high-temperature superconductivity using a rare earth element such as Gd (gadrinium) or Sm (samarium) instead of the yttrium-based superconductor (YBCO) or Y (yttrium) of YBCO. Body material is used. Other high-temperature superconductor materials include high-temperature copper oxide ceramic superconductors (BSCCO2223 and the like), thallium-barium-calcium-copper oxide-based superconductors (TBCCO), and the like.

Each winding 222 is a coil in which a strip-shaped wire rod is wound in a double pancake shape, and the shape of the coil surface is a race track shape. The double pancake type coil is a coil in which two pancake type coils, in which strip-shaped wire rods are wound with their long side surfaces overlapped with each other, are electrically connected on the innermost side. In the present embodiment, the width dimension of the strip-shaped wire rod is about 10 mm, and the thickness dimension is about 0.2 mm. The dimensions of the strip-shaped wire are not limited, and the number of turns is not limited. Further, each winding 222 may be a coil in which a plurality of double pancake type coils are connected. Further, each winding 222 may be a single pancake type instead of a double pancake type. Each winding 222 is fixed to the cylindrical portion 221 so that the longitudinal direction of the race track shape is parallel to the axial direction and the coil surface faces the cylindrical portion 221. In the present embodiment, the longitudinal dimension (axial dimension) L (see FIG. 3) of the race track shape of each winding 222 is 200 mm in accordance with the axial dimension of each permanent magnet 232. In the present embodiment, since the motor device 2 needs to output the torque for driving the vehicle 1, the axial dimension L of each winding 222 and the axial dimension of each permanent magnet 232 should be large. .. However, since the weight of the motor device 2 increases as the dimension increases, the dimension is appropriately set in consideration of the torque output and the weight. It is desirable that the axial dimension L of each winding 222 and the axial dimension of each permanent magnet 232 are 200 mm or less. Further, in the present embodiment, the lateral dimension (circumferential dimension) W (see FIG. 2) of the race track shape of each winding 222 is about 40 mm. The dimension W is appropriately set according to the softness of the strip-shaped wire and the number of windings 222 to be arranged. It is desirable to make the dimension W as small as possible and arrange as many windings 222 as possible. The dimensions of each winding 222 are not limited.

The back yoke 223 is, for example, an iron cylindrical magnetic component. The material of the back yoke 223 is not limited. The back yoke 223 is arranged on the outer side of the cylindrical portion 221 in the radial direction so as to be separated from each winding 222. The back yoke 223 shields the magnetic flux generated by each winding 222 from coming out of the stator 22 and returns it to the inside.

The container 21 is a container for accommodating the stator 22 and the rotor 23. The container 21 includes an outer container 211, an inner container 212, and a lid 214. Both the outer container 211 and the inner container 212 have a bottomed cylindrical shape, and the inner container 212 is arranged inside the outer container 211. The space surrounded by the outer container 211 and the inner container 212 is hermetically sealed and has a higher degree of vacuum than the outside. The space is a heat insulating portion 213 having a heat insulating effect. A stator 22 and a rotor 23 are housed inside the inner container 212. The lid 214 is a lid that closes the opening of the inner container 212. In this embodiment, the outer container 211, the inner container 212, and the lid 214 are made of stainless steel. The materials and shapes of the outer container 211, the inner container 212, and the lid 214 are not limited.

A coolant 24 (liquid nitrogen) is filled between the cylindrical portion 221 of the stator 22 and the inner container 212 of the container 21. Therefore, each winding 222 and the back yoke 223 are immersed in the coolant 24 and cooled to a low temperature state. As a result, each winding 222 is put into a superconducting state, and the electric resistance is remarkably lowered, so that a large current can flow and the generation of Joule heat is suppressed. Further, since each winding 222 and the back yoke 223 are strongly cooled by the coolant 24, the motor device 2 does not need to be provided with heat radiating fins or the like for cooling them.

Next, the operation and effect of the motor device 2 according to the first embodiment will be described.

According to this embodiment, the stator 22 includes a plurality of windings 222. Each winding 222 is a coil made of a superconductor material. Each winding 222 is cooled by the coolant 24 (liquid nitrogen) filled between the cylindrical portion 221 and the container 21. As a result, each winding 222 is put into a superconducting state, and the electric resistance is remarkably lowered, so that a large current can flow. Therefore, since the stator 22 can generate a large magnetic field, the motor device 2 can output a high torque. Further, the electric resistance of each winding 222 is remarkably reduced, so that the generation of Joule heat is suppressed. Further, each winding 222 is strongly cooled by the coolant 24. Therefore, the motor device 2 does not need to be provided with heat-dissipating fins or the like for cooling. As a result, the motor device 2 can be made smaller and lighter.

Further, according to the present embodiment, the rotor 23 includes a plurality of permanent magnets 232 arranged in an annular Halbach array. The plurality of permanent magnets 232 concentrate the magnetic flux on the outer peripheral surface side of the cylindrical portion of the main body 231 and increase the magnetic field strength on the outer peripheral surface side. As a result, the motor device 2 can output a high torque. On the other hand, the magnetic flux generated on the inner peripheral surface side of the cylindrical portion of the main body 231 is suppressed. Therefore, the rotor 23 does not need to have a yoke inside the cylindrical portion of the main body 231 in the radial direction. As a result, the weight of the motor device 2 can be reduced.

Further, according to the present embodiment, the rotor 23 has a main body 231 made of synthetic resin and does not have a yoke. Therefore, the rotor 23 can be reduced in weight. This contributes to the weight reduction of the motor device 2. Further, by reducing the weight of the rotor 23, the inertia of the rotor 23 is reduced, so that the responsiveness to the control of the motor device 2 is improved. Further, according to the present embodiment, the cylindrical portion 221 of the stator 22 is made of FRP, and the stator 22 does not have a yoke inside. Therefore, the stator 22 can also be reduced in weight. This contributes to the weight reduction of the motor device 2.

Further, according to the present embodiment, the axial dimension of each permanent magnet 232 and the axial dimension L of each winding 222 are 200 mm. Therefore, the motor device 2 can output a high torque for driving the vehicle 1 while suppressing the increase in size. Further, according to the present embodiment, the stator 22 is provided with 15 windings 222 arranged in the circumferential direction on the outer peripheral surface of the cylindrical portion 221. Therefore, the motor device 2 can output a high torque. In the present embodiment, the number of windings 222 is large, but the weight of the entire motor device 2 is suppressed by reducing the axial dimension L of each winding 222 and the axial dimension of each permanent magnet 232. ing. Even if the axial dimension L of the winding 222 is reduced, a large current can be passed through the winding 222, so that the motor device 2 can output a sufficient torque. Further, since the number of windings 222 is large, the vibration of the entire motor device 2 is suppressed. By suppressing the vibration, heat generation due to friction between the wires in the winding 222 can be suppressed, and the generation of hot spots can be suppressed. As a result, it is possible to suppress the occurrence of quenching that returns from the superconducting state to the normal conducting state.

Further, according to the present embodiment, each winding 222 is a coil in which a strip-shaped wire rod containing a superconductor material is wound in a double pancake shape. Therefore, both ends of the strip-shaped wire of the winding 222 are arranged outside the coil. Therefore, the connection is easy. Further, each winding 222 has a race track shape on the coil surface, and is arranged so that the longitudinal direction is parallel to the axial direction. Therefore, in the stator 22, many windings 222 can be arranged in the circumferential direction, and the dimensions in the axial direction can be increased, so that the motor device 2 can output a high torque.

Further, according to the present embodiment, the container 21 includes an outer container 211 and an inner container 212, and the space surrounded by the outer container 211 and the inner container 212 is sealed, and the degree of vacuum is higher than that of the outside. .. As a result, the inside and the outside of the container 21 are appropriately insulated, and the temperature of the cooling liquid 24 filled inside can be suppressed from rising.

In the present embodiment, the case where each permanent magnet 232 is embedded in the cylindrical portion of the main body 231 in the rotor 23 has been described, but the present invention is not limited to this. A part of each permanent magnet 232 (for example, a surface facing the stator 22) may be exposed from the cylindrical portion. Further, the rotor 23 may have each permanent magnet 232 fixed to the outside (or inside) of the cylindrical portion of the main body 231 with an adhesive, a screw, or the like. In this case, the material of the cylindrical portion of the rotor 23 may be a material other than the synthetic resin.

In the present embodiment, the case where each winding 222 is a coil in which a strip-shaped wire rod is wound in a race track shape in an overlapping manner has been described, but the present invention is not limited to this. The shape of the coil surface of each winding 222 may be rectangular, elliptical, or circular instead of the racetrack shape. Further, the wire rod of each winding 222 may have a circular cross section instead of a strip shape. In this case, each winding 222 may be a solenoid coil in which a wire rod is spirally wound, a spiral coil, a toroidal coil, or the like. Further, it may be an edgewise coil in which a strip-shaped wire rod is wound in a direction in which it is difficult to bend on the short side.

In the present embodiment, the case where the motor device 2 is used for an electric vehicle has been described, but the present invention is not limited to this. The motor device 2 may be used for other electric vehicles such as electric motorcycles, electric bicycles, and electric wheelchairs. Further, the motor device 2 can be used for all products used by converting electric power into rotational force, such as flying objects such as drones, home appliances such as vacuum cleaners, and electric tools.

The motor device according to the present invention is not limited to the above-described embodiment. The specific configuration of each part of the motor device according to the present invention can be freely redesigned.

1: Vehicle 2: Motor device 3: Coolant tank 31: Transfer tube 32: Discharge pipe 4: Storage battery 5: Inverter 21: Container 211: Outer container 212: Inner container 213: Insulation part 214: Lid 22: Stator 221: Cylindrical shape part 221a: Protruding part 222: Winding 223: Back yoke 23: Rotor 231: Main body 232: Permanent magnet 233: Shaft 24: Coolant 25: Air gap 26: Bearing

Claims (6)

A rotor with multiple permanent magnets arranged in an annular Halbach array around the central axis,
A cylindrical portion arranged so as to surround the rotor on the outer side in the radial direction of the rotor, and a plurality of cylindrical portions arranged on the outer side in the radial direction of the cylindrical portion at equal intervals along the circumferential direction. With a stator with windings,
A container for storing the stator and
With
The winding contains a superconducting material and contains
A coolant is filled between the cylindrical portion and the container.
Motor device. The winding is a coil in which a strip-shaped wire containing a superconductor material is wound in a double pancake shape, and the shape of the coil surface is a race track shape.
The motor device according to claim 1. The axial dimension of each winding, which is the extending direction of the central axis, and the axial dimension of each permanent magnet are 200 mm or less.
The number of windings is 15 or more.
The motor device according to claim 1 or 2. The container comprises an outer container and an inner container.
The space surrounded by the outer container and the inner container has a higher degree of vacuum than the outside.
The motor device according to any one of claims 1 to 3. The rotor further includes a rotor body to which the plurality of permanent magnets are fixed.
The rotor body and the cylindrical portion are made of a material containing a synthetic resin.
The motor device according to any one of claims 1 to 4. The stator further comprises a back yoke disposed radially outward of the cylindrical portion and the plurality of windings.
The motor device according to any one of claims 1 to 5.

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