JP2019103322A - Outer rotor type motor - Google Patents

Abstract

To provide an outer rotor type motor which is inexpensive and in which the problem of the magnet coming into contact with a stator hardly occurs.SOLUTION: In an outer rotor type motor 1000, a field magnetic portion 1040 of a rotor 1021 is annularly disposed about a central axis 1100, and a stator 1020 is disposed radially inward of the field magnetic portion of the rotor. In the rotor, a cylindrical portion 1103 faces the stator. A cylindrical rubber magnet 1102 is disposed radially outward of the outer peripheral surface of the cylindrical portion, along the outer peripheral surface.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an outer rotor type motor.

  The outer rotor type motor comprises a stator and a rotor. The stator is disposed radially inward of the field portion of the rotor. The stator serves as an armature to generate an armature magnetic field. The rotor becomes a field and generates a field magnetic field. The generated field magnetic field interlinks with the generated armature magnetic field. This generates torque that causes the rotor to rotate about the central axis.

  The rotor comprises a rotor holder and a magnet. The magnet generates a field magnetic field.

  Magnets incorporated into a rotor are roughly classified into sintered magnets, plastic magnets and rubber magnets.

  When the magnet incorporated into the rotor is a sintered magnet or a plastic magnet, the magnet is deformed or moved toward the stator by magnetic interaction, heat, external force, etc. between the stator and the magnet, and the magnet is a tooth of the stator, etc. It is hard to occur the problem of touching. However, when the magnet incorporated into the rotor is a sintered magnet or a plastic magnet, the magnet is not inexpensive and storage, processing and incorporation into the rotor become difficult.

  On the other hand, when the magnet incorporated in the rotor is a rubber magnet, the above-mentioned problem is likely to occur. In particular, when the rubber magnet is a neodymium (Nd) rubber magnet, the above-mentioned problems are likely to be noticeable. However, if the magnet incorporated into the rotor is a rubber magnet, the magnet becomes inexpensive and storage, processing and incorporation into the rotor become easy.

The motor described in Patent Document 1 is an example of an outer rotor type motor. In the motor described in Patent Document 1, the rotor magnet is disposed on the inner peripheral surface of the cup-shaped rotor yoke (paragraph 0011). In the motor described in Patent Document 1, the rotor magnet is a rubber magnet (paragraph 0012).
JP, 2016-197899, A

  As described above, when the magnet incorporated in the rotor provided to the outer rotor type motor is a sintered magnet or a plastic magnet, the magnet is not inexpensive and storage, processing and incorporation into the rotor become difficult. . On the other hand, when the magnet incorporated in the rotor provided in the outer rotor type motor is a rubber magnet, the problem of the magnet coming into contact with the stator tends to occur under high temperature environment.

  For this reason, in the prior art, it is difficult to obtain an outer rotor type motor which is an inexpensive rubber magnet and hardly causes the problem of contact with the stator.

  The present invention aims to solve this problem. The problem to be solved by the present invention is to provide an outer rotor type motor which is inexpensive and in which the problem of the magnet coming into contact with the stator hardly occurs.

  In an exemplary embodiment of the present invention, in an outer rotor type motor, a field section provided on a rotor is annularly disposed about a central axis, and a stator is disposed radially inward of the rotor. In the rotor, the cylindrical portion faces the stator, and a cylindrical rubber magnet is disposed radially outside the outer peripheral surface of the cylindrical portion along the outer peripheral surface.

  According to an exemplary embodiment of the present invention, a rubber magnet is incorporated into the rotor that is easy to store, machined and integrated into the rotor and is inexpensive. Thus, an inexpensive outer rotor type motor can be provided.

  Also, according to an exemplary embodiment of the present invention, a tubular portion is present radially inside the rubber magnet. As a result, it is restricted by the cylindrical portion that the rubber magnet is deformed or moved toward the stator by magnetic interaction between the stator and the rubber magnet, heat, external force or the like, and the rubber magnet contacts the stator. It can prevent.

It is a sectional view which illustrates a motor of a 1st embodiment typically. FIG. 2 is a cross-sectional view schematically illustrating a rotor, a magnetic sensor, and a substrate provided in the motor of the first embodiment. It is a sectional view which illustrates a rubber magnet provided in a motor of a 1st embodiment typically.

  Hereinafter, exemplary embodiments of the present invention will be described with reference to the drawings. In the present application, a direction parallel to the central axis C of the motor is “axial direction”, a direction orthogonal to the central axis of the motor is “radial direction”, and a direction along an arc centered on the central axis C of the motor is “peripheral It is referred to as “direction”. Further, in the present application, the shape and the positional relationship of each part will be described with the axial direction as the vertical direction. However, the definition in the vertical direction is not intended to limit the direction at the time of manufacture and use of the motor according to the present invention.

  Further, in the present application, the “parallel direction” also includes a substantially parallel direction. Further, in the present application, the “orthogonal direction” also includes a substantially orthogonal direction.

1 First Embodiment 1.1 Outline of Motor FIG. 1 is a cross-sectional view schematically illustrating a motor according to a first embodiment.

  The motor 1000 illustrated in FIG. 1 is an outer rotor type, and includes a stator 1020, a rotor 1021, a case 1022, a bearing 1023, and a bearing 1024. Motor 1000 may comprise components other than these components.

  The case 1022 is a cylindrical member extending in the axial direction. The material of the case 1022 is not particularly limited, and, for example, aluminum (including an aluminum alloy), an iron alloy such as SUS, and the like are preferable. The stator 1020 is fixed to the outer peripheral surface of the case 1022 by, for example, press fitting or adhesion.

  A bearing 1024 is held inside the axially lower side of the case 1022. The bearing 1024 is fixed to the inner side surface of the case 1022 by, for example, press fitting. A bearing 1023 is fixed to an inner circumferential surface of a stator core described later. In the present embodiment, the bearings 1023 and 1024 are ball bearings. The types of bearings 1023 and 1024 are not limited to ball bearings, but may be other types of bearings such as slide bearings.

  The rotor 1021 is rotatably supported relative to the case 1022 by bearings 1023 and 1024.

  The stator 1020 serves as an armature to generate an armature magnetic field. The rotor 1021 becomes a field and generates a field magnetic field. The generated field magnetic field interlinks with the generated armature magnetic field. As a result, torque that causes the rotor 1021 to rotate around the central axis C is generated.

  The motor 1000 is an outer rotor type. For this reason, in the motor 1000, the stator 1020 is disposed radially inward of the field portion 1040 of the rotor 1021. The field portion 1040 of the rotor 1021 is annularly disposed around the central axis C.

1.2 Stator The stator 1020 comprises a stator core 1060 and a plurality of windings 1061 as illustrated in FIG. The stator core 1060 includes a core back 1080 and a plurality of teeth 1081.

  In the present embodiment, the core back 1080 is annular, and is disposed annularly around the central axis C. The plurality of teeth 1081 project radially outward from the outer circumferential surface 1110 of the core back 1080. The teeth 1081 are distributed in the circumferential direction around the central axis C. In the present embodiment, the teeth 1081 are arranged on the outer circumferential surface of the core back 1080 at equal intervals in the circumferential direction. A conductive wire is wound around each tooth 1081 through an insulator made of an insulating material to form a winding 1061.

  The stator core 1060 is made of a magnetic material. In the present embodiment, the stator core 1040 is a laminated steel plate in which a plurality of electromagnetic steel plates are laminated in the axial direction. When current flows through the plurality of windings 1061, an armature magnetic field is generated according to the current. The stator core 1040 may be a powder magnetic core or the like instead of the laminated steel plate.

  The inner circumferential surface of the core back 1080 has a small diameter portion and a large diameter portion. The large diameter portion is located axially above the small diameter portion. The inner diameter of the large diameter portion is larger than the inner diameter of the small diameter portion. The inner diameter portion is fixed to the outer peripheral surface of the case 1020. A bearing 1023 is held at the large diameter portion. The bearing 1023 axially faces the opening at the upper side in the axial direction of the case 1020.

  The stator 1020 having the structure illustrated in FIG. 1 may be replaced with a stator having a structure different from the structure. The above-mentioned stator core 1040 is a round core whose core back is annular. However, the stator core 1060 is not limited to a round core, and may be any of so-called split cores and straight cores, or may be cores of other shapes. The winding method of the plurality of windings 1061 may be either concentrated winding or distributed winding, or may be other winding method.

1.3 Rotor FIG. 2 is a cross-sectional view schematically illustrating a rotor, a magnetic sensor, and a substrate provided in the motor of the first embodiment. FIG. 2 is an enlarged view of a part of FIG.

  As illustrated in FIGS. 1 and 2, the rotor 1021 includes a shaft 1100, a rotor holder 1101, a rubber magnet, and a cylindrical portion 1103.

  Shaft 1100 is coupled to the inner rings of bearings 1023 and 1024. The inner rings of bearings 1023 and 1024 can rotate relative to the outer rings of bearings 1023 and 1024, respectively. The outer ring of the bearing 1024 is coupled to the case 1022. The outer ring of the bearing 1023 is fixed to the inner circumferential surface (large diameter portion) of the core back. Thereby, the shaft 1100 can rotate around the central axis C in a state along the central axis C.

  Rotor holder 1101 is coupled to shaft 1100. The rubber magnet 1102 is attached to the rotor holder 1101. Thus, the rubber magnet 1102 can rotate integrally with the shaft 1100.

  The rubber magnet 1102 has a cylindrical shape, and is disposed in a cylindrical shape centering on the central axis C. The magnet inner circumferential surface 1120 of the rubber magnet 1102 is multipolar-magnetized to be a multipolar magnetized surface. Thereby, the magnet inner circumferential surface 1120 generates a field magnetic field.

1.4 Rotor Holder The rotor holder 1101 is a covered cylindrical body. As illustrated in FIG. 2, the rotor holder 1101 includes a cylindrical structure 1140 and a plate-like structure 1141. The cylindrical structure portion 1140 is a cylindrical member and extends in the axial direction.

  The plate-like structure portion 1141 is a lid-like portion that closes at least a part of the upper opening of the cylindrical structure portion 1140. The cylindrical structure 1140 extends axially downward from the radial outer end of the plate-like structure 1141. The plate end 1160 on the outer peripheral side of the plate-like structure 1141 is coupled to the upper tube end 1180 of the tubular structure 1140. In the present embodiment, the structural portion 1141 and the cylindrical structural portion 1140 are integrally formed by press processing, cutting, or the like. In other words, the rotor holder is a single member. Therefore, the plate end 1160 is integral with the tube end 1180. However, the structural portion 1141 and the tubular structure 1140 may be separately formed and combined.

  The rubber magnet 1102 and the cylindrical structure portion 1140 constitute a field portion 1040. A rubber magnet 1102 is attached to the inner circumferential surface 1200 of the tubular structure 1140. Thus, the rubber magnet 1102 is surrounded by the cylindrical structure 1140. The rubber magnet 1102 may be surrounded by a cylindrical structure other than the cylindrical structure 1140 which forms a part of the rotor holder 1101. For example, when the motor is incorporated into a blower, the rubber magnet 1102 may be surrounded by a tubular structure constituting an impeller provided to the blower.

  In the present embodiment, the material of the rotor holder 1101 is made of a magnetic material. A plurality of structural parts which constitute rotor holder 1101 may be constituted from mutually different materials. For example, the cylindrical structure portion 1140 may be made of a magnetic material such as metal, and the plate-like structure portion 1141 may be a nonmagnetic material such as a resin.

1.5 Advantages of Rubber Magnet The cylindrical rubber magnet 1102 illustrated in FIGS. 1 and 2 can be easily obtained by a business or the like who manufactures the motor 1000 by deforming a flat rubber magnet into a cylindrical shape. Be Moreover, the flat rubber magnet does not require, for example, a large space for storage, and can be easily stored. Furthermore, when a flat rubber magnet is deformed into a cylindrical shape, a dedicated mold is not necessary. Therefore, when the magnet incorporated into the rotor 1021 is a rubber magnet 1102, storage, processing, and incorporation into the rotor 1021 are easy. In addition, a binding material for binding magnetic particles to each other in the rubber magnet 1102 is inexpensive. For this reason, when the magnet incorporated in the rotor 1021 is a rubber magnet 1102, the magnet becomes inexpensive. Therefore, when the magnet incorporated in the rotor 1021 is the rubber magnet 1102, an inexpensive motor 1000 can be provided.

  During driving of the motor, a radial electromagnetic force is generated between the teeth and the magnet. Due to the electromagnetic force, vibrations occur in the teeth and the magnet, and noise may be generated from the motor. In particular, when the magnet incorporated in the rotor 1021 is a plastic magnet or a sintered magnet, the noise is less likely to be attenuated. Further, in the case where the magnet incorporated in the rotor 1021 is a plastic magnet or a sintered magnet, there is also a possibility that the resonance noise may be changed by the amount of adhesive bonding the magnet to the rotor main body. On the other hand, in the present embodiment, the rubber magnet 1102 has elasticity. Thus, the vibration due to the radial electromagnetic force generated between the teeth 1081 and the rubber magnet 1102 when the rotor 1021 rotates is attenuated by the rubber magnet 1102. As a result, the noise generated from the motor 1000 is suppressed.

1.6 Preventing Contact of Rubber Magnet to Stator When the magnet incorporated in the rotor 1021 shown in FIGS. 1 and 2 is the rubber magnet 1102, the magnetic interaction between the stator 1020 and the rubber magnet 1102 The rubber magnet 1102 may be deformed or moved toward the stator 1020 by heat, external force or the like. Therefore, these deformation or movement must be restricted to prevent the rubber magnet 1102 from contacting the stator 1020. Below, the structure for that is demonstrated.

  The rotor 1021 further includes a tubular portion 1103. In the present embodiment, the cylindrical portion 1103 is a nonmagnetic material such as aluminum (including an aluminum alloy).

  The cylindrical portion 1103 constitutes a field portion 1040. The cylindrical portion 1103 does not deform as much as it contacts the stator 1020 even when the rotor 1021 rotates. The cylindrical portion 1103 is disposed in a cylindrical shape centering on the central axis C, and radially opposed to the stator 1020.

  The rubber magnet 1102 is disposed radially outward of the outer peripheral surface 1220 of the cylindrical portion 1103 and extends along the outer peripheral surface 1220.

  A cylindrical portion 1103 is present radially inward of the rubber magnet 1102. Thus, the cylindrical portion 1103 restricts the rubber magnet 1102 from being deformed or moved toward the stator 1020. As a result, the rubber magnet 1102 can be prevented from contacting the stator 1020.

  In the present embodiment, the cylindrical portion 1103 does not have to function as a so-called yoke. Therefore, as described above, the cylindrical portion 1103 is a nonmagnetic material.

1.7 Detection of circumferential position of rotor The cylindrical rubber magnet 1102 has a first multipole magnetization surface facing inward in the radial direction and a second multipole magnetization surface facing in a direction different from the inward direction in the radial direction. Have. The outer rotor type motor further includes a magnetic sensor 1260 that faces the second multipolar magnetization surface and detects a magnetic field generated by the second multipolar magnetization surface.

  The magnet inner circumferential surface 1120 of the rubber magnet 1102 shown in FIG. 2 is directed inward in the radial direction, and is a first multipolar magnetized surface that generates a field magnetic field.

  In the motor 1000, the lower end face 1240 of the rubber magnet 1102 is directed axially downward to become a second multipolar magnetized surface which generates a magnetic field used to detect the circumferential position of the rotor 1021. ing.

  The motor 1000 further comprises at least one magnetic sensor 1260 and a substrate 1261. In the present embodiment, the substrate 1261 is, for example, a plate-like member. The substrate 1261 is supported by a part of the case 1002. In the present embodiment, the substrate 1261 axially faces the stator and the rotor. Various electronic components such as a capacitor are electrically connected to at least one surface in the axial direction one side and the other axial direction side of the substrate 1261. The substrate 1261 is connected to an external power supply (not shown) via a connector or the like. Further, the substrate 1261 is connected to the winding directly or indirectly via a conductive member such as a lead, for example. Thereby, power can be supplied to the motor (i.e., the stator) through the external power supply. In the present embodiment, the substrate 1261 is a so-called printed circuit board (PCB). However, the substrate 1261 is not limited to a printed circuit board (PCB), and may be a flexible printed circuit (FPC) or the like. The number of substrates 1261 is not limited to one, and may be two or more. The substrate 1321 may be a single-sided substrate on which an electronic component or the like is mounted on one side, or may be a double-sided substrate on which an electronic component or the like is mounted on both sides.

  The magnetic sensor 1260 is a position sensor that detects the circumferential position of the rotor 1021. The magnetic sensor 1260 is mounted on the substrate 1261 and faces the lower end surface 1240 of the rubber magnet 1102 at a specific position in the circumferential direction. Thereby, the magnetic sensor 1260 detects the magnetic field generated by the end face 1240 and outputs an electric signal according to the detected magnetic field. The output electrical signal is used to detect the circumferential position of the rotor 1021. The magnetic sensor 1260 may be either a Hall element or a magnetoresistive element, or may be another element. The magnetic sensor 1260 may detect a magnetic field generated by the magnet outer peripheral surface 1121 of the rubber magnet 1102 in addition to the magnetic field generated by the end face 1240. The number of magnetic sensors 1320 may be one or three or more, and can be appropriately changed in accordance with the number of magnetic poles of the rotor, the number of phases, and the like.

  When the magnet is a sintered magnet having strong anisotropy, it is necessary to provide a sensor magnet independent of the sintered magnet that generates a field magnetic field and a magnetic sensor that detects the magnetic field generated by the sensor magnet. become. On the other hand, in the present embodiment, the rubber magnet 1102 is desirably an isotropic magnet or an anisotropic magnet having weak anisotropy that can be magnetized in a direction different from the direction in which the magnetization easy axis extends. More preferably, they are isotropic magnets. When the rubber magnet 1102 is an isotropic magnet or an anisotropic magnet having weak anisotropy, an axially lower side different from the magnet inner circumferential surface 1120 of the rubber magnet 1102 facing inward in the radial direction and the radially inner side It is easy to magnetize both of the lower end faces 1240 of the rubber magnet 1102 facing the This makes it unnecessary to provide a sensor magnet independent of the rubber magnet 1102 to detect the circumferential position of the rotor 1021 and a magnetic sensor for detecting the magnetic field generated by the sensor magnet, and the manufacturing cost of the motor 1000 Can be lowered.

  The lower end surface 1240 of the rubber magnet 1102 protrudes axially downward from the cylindrical portion 1103 as illustrated in FIG. 2. This makes it easy to arrange the magnetic sensor 1260 near the end face 1240, and the magnetic field generated by the end face 1240 can be efficiently detected by the magnetic sensor 1260.

  An upper end surface 1241 of the rubber magnet 1102 which faces the axial direction upper side protrudes axially upward from the cylindrical portion 1103. The end face 1241 is a multipolar magnetized surface that generates a magnetic field used to detect the circumferential position of the rotor 1021. The magnetic sensor 1260 faces the end face 1241.

1.8 Attachment of Rubber Magnet The rubber magnet 1102 illustrated in FIG. 2 is attached to the inner circumferential surface 1200 of the tubular structure 1140 by any attachment method. For example, the rubber magnet 1102 is attached to the inner circumferential surface 1200 by squeezing it into the cylindrical structure 1140 and pressing it onto the inner circumferential surface 1200. According to such an attachment method, the rubber magnet 1102 is attached by an attachment process simpler than the attachment process in the case of attaching a sintered magnet. The rubber magnet 1102 may be attached to the inner circumferential surface 1200 of the cylindrical structure 1140 by another method such as adhesion.

1.9 Types of Magnets The rubber magnet 1102 illustrated in FIGS. 1 and 2 is either a ferrite rubber magnet composed of a composition containing ferrite or an Nd rubber magnet composed of a composition containing neodymium (Nd) Although it may be good or another rubber magnet, it is preferably an Nd rubber magnet. Nd rubber magnets have the same magnetic force as ferrite rubber magnets occupying a larger volume. For this reason, when generating the same magnetic force, when the rubber magnet 1102 is an Nd rubber magnet, the volume of the magnet can be reduced to reduce the volume of the rotor as compared to the case where a ferrite rubber magnet is used. it can. As a result, the motor 1000 can be miniaturized.

  Nd rubber magnets are less expensive than Nd plastic magnets containing Nd and Nd sintered magnets. Therefore, when the magnet incorporated into the rotor 1021 is an Nd rubber magnet, the inexpensive motor 1000 can be provided. The Nd plastic magnet is more expensive than the Nd rubber magnet because it is necessary to use epoxy, polyamide (PA), poniphenylene sulfide (PPS) or the like as a binder in the Nd plastic magnet. The reason why the Nd sintered magnet is more expensive than the Nd rubber magnet is that the Nd content in the Nd sintered magnet is larger than the Nd content in the Nd rubber magnet.

  In a general Nd rubber magnet, magnetic particles made of NeFeB-based magnetic material are bound to one another by nitrile rubber. However, the force with which the nitrile rubber fixes the magnetic powder is not sufficient for the magnetic force of the magnetic powder. Therefore, when a general Nd rubber magnet is simply incorporated into a rotor provided in a conventional outer rotor type motor, there may be a problem caused by the insufficient force. For example, when an outer rotor type motor including a rotor incorporating a stator and a 10 pole magnetized Nd rubber magnet is left assembled, the magnetic powder is attracted to the stator core and the Nd rubber magnet is disposed at 10 places. The problem of contact with the stator core may occur. However, in the motor 1000, the rubber magnet 1102 is disposed on the radially outer side of the cylindrical portion 1103, so that the problem can be prevented.

1.10 Halbach Arrangement FIG. 3 is a cross-sectional view schematically illustrating a rubber magnet provided in the motor of the first embodiment.

  The rubber magnet 1102 illustrated in FIG. 3 is magnetized in eight poles. The number of magnetic poles in the rubber magnet 1103 may be other than eight.

  The rubber magnet 1102 is preferably an isotropic magnet, and includes a plurality of magnetized portions 1400 magnetized in the Halbach arrangement and magnetized in the Halbach arrangement as illustrated in FIG. 3. The cylindrical rubber magnet 1102 has a magnet inner circumferential surface 1120 and a magnet outer circumferential surface 1121. As a result, the magnetic flux is concentrated on the magnet inner circumferential surface 1120 of the rubber magnet 1102 and the magnetic field generated by the magnet inner circumferential surface 1120 of the rubber magnet 1102 becomes stronger than the magnetic field generated by the magnet outer circumferential surface 1121 of the rubber magnet 1102 . The fact that the magnetic field generated by the magnet inner circumferential surface 1120 is strengthened by being magnetized in the Halbach arrangement means that the torque generated by the motor 1000 is increased while maintaining the volume, shape and material of the rubber magnet 1102. To contribute.

  The plurality of magnetized portions 1400 are arranged in the circumferential direction. The plurality of magnetized portions 1400 includes a radially magnetized portion 1420 magnetized in the radial direction and a circumferential magnetized portion 1421 magnetized in the circumferential direction. In the plurality of magnetized portions 1400, the radially magnetized portions 1420 and the circumferentially magnetized portions 1421 are alternately arranged. The plurality of radially magnetized portions 1420 have a first type radially magnetized portion 1440 whose S pole is exposed on the magnet inner circumferential surface 1120 of the rubber magnet 1102 and an N pole on the magnet inner circumferential surface 1120 of the rubber magnet 1102. It includes a second radially magnetized portion 1441 that is exposed. In the plurality of radially magnetized portions 1420, the first radially magnetized portions 1440 and the second radially magnetized portions 1441 are alternately arranged. In the two circumferential magnetization parts 1421 adjacent to the first radial magnetization part 1440, the direction from the S pole to the N pole is a direction away from the first radial magnetization part 1440. . In the two circumferential magnetization parts 1421 adjacent to the second radial magnetization part 1441, the direction from the S pole to the N pole is a direction approaching the second radial magnetization part 1441. .

  The rubber magnet 1102 disposed in a cylindrical shape about the central axis C may be replaced with a plurality of rubber magnets arranged in the circumferential direction about the central axis C. The plurality of rubber magnets are magnetized in the same manner as the plurality of magnetized portions 1400 provided in the rubber magnet 1102, respectively.

1.11 Shape and Application of Motor When the magnet incorporated in the rotor 1021 is a rubber magnet 1102, the torque generated by the motor 1000 can be increased without increasing the axial dimension of the field portion 1040 of the rotor 1021. Therefore, when the magnet incorporated in the rotor 1021 is a rubber magnet 1102, it is compact, has a flat shape in which the outer diameter φ of the field portion 1040 is larger than the axial dimension of the field portion 1040, and has high torque Can easily be obtained. The outer diameter φ of the realizable field portion 1040 is, for example, about 85 mm, and the axial dimension of the realizable field portion 1040 is, for example, 3 mm to 7 mm.

  The present invention can be widely used not only for power slides, but also for various devices equipped with various motors such as vacuum cleaners, dryers, ceiling fans, washing machines, refrigerators and electric power steering devices.

  Although the present invention has been described in detail, the above description is an exemplification in all aspects, and the present invention is not limited thereto. It is understood that countless variations not illustrated are conceivable without departing from the scope of the present invention.

1000 motor 1020 stator 1021 rotor 1101 rotor holder 1102 rubber magnet 1103 cylindrical portion 1140 cylindrical structure portion 1260 magnetic sensor C central axis

Claims (8)

A rotor comprising a field section arranged annularly around a central axis;
A stator disposed radially inward of the field portion;
Equipped with
The rotor is
A cylindrical portion having an outer peripheral surface and facing the stator;
A cylindrical rubber magnet disposed radially outward of the outer peripheral surface and along the outer peripheral surface;
Outer rotor type motor with. The cylindrical rubber magnet has a first multipolar magnetized surface facing inward in the radial direction and a second multipolar magnetized surface facing in a direction different from the radially inner side.
The outer rotor type motor according to claim 1, wherein the outer rotor type motor further comprises a magnetic sensor that faces the second multipolar magnetization surface and detects a magnetic field generated by the second multipolar magnetization surface. Motor. 3. An outer rotor type motor according to claim 2, wherein said second multipolar magnetized surface protrudes axially from said cylindrical portion and faces in the axial direction. The outer rotor type motor according to claim 2 or 3, wherein the cylindrical rubber magnet is an isotropic magnet. The cylindrical rubber magnet includes a plurality of magnetized portions magnetized in a Halbach arrangement, and has an inner circumferential surface and an outer circumferential surface of the magnet.
The outer rotor type motor according to any one of claims 1 to 4, wherein the magnetic field generated by the inner peripheral surface of the magnet is stronger than the magnetic field generated by the outer peripheral surface of the magnet. The outer rotor type motor according to any one of claims 1 to 5, wherein an outer diameter of the field portion is larger than an axial dimension of the field portion. The outer rotor type motor according to any one of claims 1 to 6, wherein the cylindrical portion is made of a nonmagnetic material. The outer rotor type motor according to any one of claims 1 to 7, further comprising a tubular structure surrounding the tubular rubber magnet.

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