US20140009044A1 - Rotating electrical machine - Google Patents

Rotating electrical machine Download PDF

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Publication number
US20140009044A1
US20140009044A1 US13/935,715 US201313935715A US2014009044A1 US 20140009044 A1 US20140009044 A1 US 20140009044A1 US 201313935715 A US201313935715 A US 201313935715A US 2014009044 A1 US2014009044 A1 US 2014009044A1
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United States
Prior art keywords
magnetic
electrical machine
rotating electrical
tooth portions
rotor
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
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US13/935,715
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English (en)
Inventor
Makoto Taniguchi
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Denso Corp
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Denso Corp
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Assigned to DENSO CORPORATION reassignment DENSO CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: TANIGUCHI, MAKOTO
Publication of US20140009044A1 publication Critical patent/US20140009044A1/en
Priority to US15/297,734 priority Critical patent/US9929629B2/en
Abandoned legal-status Critical Current

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K15/00—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines
    • H02K15/04—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines of windings, prior to mounting into machines
    • H02K15/0435—Wound windings
    • H02K11/0021—
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K21/00—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets
    • H02K21/12—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets
    • H02K21/14—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets with magnets rotating within the armatures
    • H02K21/16—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets with magnets rotating within the armatures having annular armature cores with salient poles
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
    • H02K1/12—Stationary parts of the magnetic circuit
    • H02K1/14—Stator cores with salient poles
    • H02K1/146—Stator cores with salient poles consisting of a generally annular yoke with salient poles
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
    • H02K1/22—Rotating parts of the magnetic circuit
    • H02K1/27—Rotor cores with permanent magnets
    • H02K1/2706—Inner rotors
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
    • H02K1/22—Rotating parts of the magnetic circuit
    • H02K1/27—Rotor cores with permanent magnets
    • H02K1/2706—Inner rotors
    • H02K1/272—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis
    • H02K1/274—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of two or more circumferentially positioned magnets
    • H02K1/2746—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of two or more circumferentially positioned magnets the rotor consisting of magnets arranged with the same polarity, e.g. consequent pole type
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
    • H02K1/22—Rotating parts of the magnetic circuit
    • H02K1/27—Rotor cores with permanent magnets
    • H02K1/2706—Inner rotors
    • H02K1/272—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis
    • H02K1/274—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of two or more circumferentially positioned magnets
    • H02K1/2753—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of two or more circumferentially positioned magnets the rotor consisting of magnets or groups of magnets arranged with alternating polarity
    • H02K1/278—Surface mounted magnets; Inset magnets
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K11/00—Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection
    • H02K11/20—Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection for measuring, monitoring, testing, protecting or switching
    • H02K11/21—Devices for sensing speed or position, or actuated thereby
    • H02K11/215—Magnetic effect devices, e.g. Hall-effect or magneto-resistive elements
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K11/00—Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection
    • H02K11/30—Structural association with control circuits or drive circuits
    • H02K11/38—Control circuits or drive circuits associated with geared commutator motors of the worm-and-wheel type
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K15/00—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines
    • H02K15/02—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines of stator or rotor bodies
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K15/00—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines
    • H02K15/02—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines of stator or rotor bodies
    • H02K15/024—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines of stator or rotor bodies with slots
    • H02K15/026—Wound cores
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K15/00—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines
    • H02K15/06—Embedding prefabricated windings in machines
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K15/00—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines
    • H02K15/08—Forming windings by laying conductors into or around core parts
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K29/00—Motors or generators having non-mechanical commutating devices, e.g. discharge tubes or semiconductor devices
    • H02K29/06—Motors or generators having non-mechanical commutating devices, e.g. discharge tubes or semiconductor devices with position sensing devices
    • H02K29/08—Motors or generators having non-mechanical commutating devices, e.g. discharge tubes or semiconductor devices with position sensing devices using magnetic effect devices, e.g. Hall-plates, magneto-resistors
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K3/00—Details of windings
    • H02K3/04—Windings characterised by the conductor shape, form or construction, e.g. with bar conductors
    • H02K3/18—Windings for salient poles
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
    • H02K7/08—Structural association with bearings
    • H02K7/083—Structural association with bearings radially supporting the rotary shaft at both ends of the rotor
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K2213/00—Specific aspects, not otherwise provided for and not covered by codes H02K2201/00 - H02K2211/00
    • H02K2213/03—Machines characterised by numerical values, ranges, mathematical expressions or similar information
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49002—Electrical device making
    • Y10T29/49009—Dynamoelectric machine
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49002—Electrical device making
    • Y10T29/49009—Dynamoelectric machine
    • Y10T29/49012—Rotor

Definitions

  • the present disclosure relates to a rotating electrical machine.
  • a semiconductor magnetic sensor is used to detect a relative rotation angle of a rotor with respect to a stator.
  • a secondary magnet is placed at a position corresponding to the semiconductor magnetic sensor.
  • a secondary magnet is placed at an end of a shaft rotating with a rotor so that a semiconductor magnetic sensor can detect a relative rotation angle of the rotor without the influence of a magnetic field which is caused by electric current in a winding and a magnetic pole of the rotor.
  • a position of a secondary magnet with respect to a magnetic pole is important when a relative rotation angle of a rotor with respect to a stator is detected by using a semiconductor magnetic sensor. It is noted that a relative rotation angle of a rotor with respect to a stator is hereinafter sometimes referred to as the “rotational position of a rotor”.
  • a relative rotation angle of a rotor with respect to a stator is hereinafter sometimes referred to as the “rotational position of a rotor”.
  • n i.e.,
  • the rotor may rotate upon application of accidental external force when a secondary magnet is fixed to a rotor. If this occurs, the secondary magnet is not fixed in a correct position with respect to a magnetic pole. As a result, a rotational position of a rotor is not accurately detected by using a semiconductor magnetic sensor.
  • a rotating electrical machine includes a supporting member, a stator core, a winding set, a shaft, a rotor, a magnetic generator, and a magnetic detector.
  • the stator core has a ring-shaped yoke held inside the supporting member and tooth portions projecting from the yoke in a radial inward direction of the yoke.
  • the winding set is wound on the tooth portions.
  • the shaft extends through the stator core and is rotatably supported by the supporting member.
  • the rotor is located in the stator core and rotates with the shaft.
  • the magnetic generator is located at an end of the shaft.
  • the magnetic detector outputs a signal indicative of a change in magnetic flux density created by the magnetic generator. The number of the tooth portions for every magnetic pole pair in the rotor is even.
  • FIG. 1 is a diagram illustrating a cross-sectional view, taken along line I-I in FIG. 2 , of a rotating electrical machine according to a first embodiment of the present disclosure
  • FIG. 2 is a diagram illustrating a cross-sectional view taken along line II-II in FIG. 1 ;
  • FIG. 3 is a diagram illustrating an electrical configuration of the rotating electrical machine according to the first embodiment
  • FIG. 4A is a diagram illustrating a cross-sectional view of a rotating electrical machine, as a reference example, in which the number of tooth portions for every magnetic pole pair is even
  • FIG. 4B is a diagram illustrating a cross-sectional view of a rotating electrical machine, as a reference example, in which the number of tooth portions for every magnetic pole pair is odd;
  • FIG. 5 is a diagram illustrating a cross-sectional view of a rotating electrical machine according to a second embodiment of the present disclosure
  • FIG. 6 is a diagram illustrating a cross-sectional view of a rotating electrical machine according to a third embodiment of the present disclosure
  • FIG. 7 is a diagram illustrating a cross-sectional view of a rotating electrical machine according to a fourth embodiment of the present disclosure.
  • FIG. 8 is a diagram illustrating a cross-sectional view of a rotating electrical machine according to a fifth embodiment of the present disclosure.
  • FIG. 9 is a diagram illustrating a view from an arrow IX in FIG. 8 .
  • a rotating electrical machine 1 according to a first embodiment of the present disclosure is described below with reference to FIGS. 1 , 2 , and 3 .
  • the rotating electrical machine 1 includes a motor 5 and a controller 7 .
  • the motor 5 is a three-phase brushless motor.
  • the motor 5 includes a first housing 10 (as a supporting member), a stator 20 , and a rotor 30 .
  • the first housing 10 includes a tube 11 , a first side portion 12 , and a second side portion 15 .
  • a first end of the tube 11 is closed with the first side portion 12 .
  • a second end of the tube 11 is closed with the second side portion 15 .
  • a bearing 14 is fitted in a through hole 13 in the center of the first side portion 12 .
  • a bearing 17 is fitted in a through hole 17 in the center of the second side portion 15 .
  • the stator 20 includes a stator core 21 and a winding set 22 .
  • the stator core 21 is located in the tube 11 of the first housing 10 .
  • the winding set 22 is wound on the stator core 21 .
  • the stator core 21 has a ring-shaped yoke 28 and tooth portions 29 .
  • the yoke 28 is pressed into the tube 11 so that the yoke 28 can be pressed against and fixed to an inner surface of the tube 11 .
  • the tooth portions 29 project from the yoke 28 in a radial inward direction of the yoke 28 .
  • the yoke 28 and the tooth portions 29 are formed as a single piece. According to the first embodiment, twenty-four tooth portions 29 are arranged at an interval of 15 degrees in a circumferential direction of the yoke 28 .
  • the winding set 22 includes a U-phase winding, a V-phase winding, and a W-phase winding.
  • a slot 25 is formed between adjacent tooth portions 29 .
  • Each winding of the winding set 22 is wound in every third slot 25 . That is, each winding of the winding set 22 is wound at intervals of three slots 25 . In other words, each winding of the winding set 22 is wound at intervals of three tooth portions 29 .
  • the three tooth portions 29 providing each interval are positioned to face one primary magnet of the rotor 30 .
  • each winding of the winding set 22 is wound on the tooth portions 29 at intervals of an electrical angle of n (i.e.,) 180°.
  • FIG. 2 shows a direction of an electric current flowing through the U-phase winding only.
  • the rotor 30 includes a rotor core 32 and primary magnets 41 , 42 , 43 , 44 , 45 , 46 , 47 , and 48 .
  • the rotor core 32 is made of steel plates that are laminated in a direction of a rotation axis ⁇ . Each steel plate is made from soft magnetic material.
  • the primary magnets 41 , 42 , 43 , 44 , 45 , 46 , 47 , and 48 are located on the outside of the rotor core 32 in a radial direction of the rotor core 32 .
  • the rotor core 32 serves as a yoke for conducting a magnetic flux expelled from the primary magnets 41 , 42 , 43 , 44 , 45 , 46 , 47 , and 48 .
  • Eight magnetic poles are provided by the primary magnets 41 , 42 , 43 , 44 , 45 , 46 , 47 , and 48 to surround the outside of the rotor core 32 in the radial direction of the rotor core 32 .
  • each of the primary magnets 41 , 43 , 45 , and 47 forms a south pole at the rotor core 32
  • each of the primary magnets 42 , 44 , 46 , and 48 forms a north pole at the rotor core 32
  • sixth tooth portions 29 are provided for every magnetic pole pair of different types of magnetic poles.
  • tooth portions 29 are provided for each of the primary magnets 41 , 42 , 43 , 44 , 45 , 46 , 47 , and 48 .
  • tooth portions 291 , 292 , and 293 are positioned to face the primary magnet 41
  • tooth portions 294 , 295 , and 296 are positioned to face the primary magnet 42 .
  • the tooth portions 291 - 296 are part of the tooth portions 29 .
  • a shaft 31 is inserted in a through hole formed in the center of the rotor core 32 .
  • the shaft 31 is rotatably supported by the bearings 14 and 17 .
  • a second magnet 52 (as a magnetic generator) is fixed to the shaft 31 in such a manner that the second magnet 52 can generate a magnetic flux perpendicular to an axis direction of the shaft 31 .
  • the secondary magnet 52 is held in a casing (not shown), and the casing is pressed fitted to an end of the shaft 31 on the second side portion 15 side.
  • the secondary magnet 52 is fixed to the end of the shaft 31 .
  • the controller 7 is connected to the motor 5 on the second side portion 15 side.
  • the controller 7 includes a second housing 50 , a magnetic sensor 51 (as a magnetic detector), a signal board 56 (as a processor), a power board 61 (as an energization controller), and a connector 58 for connecting the signal board 56 and the power board 61 .
  • the magnetic sensor 51 , the signal board 56 , the power board 61 , and the connector 58 are accommodated in space defined by the second housing 50 and the second side portion 15 .
  • the magnetic sensor 51 is located to face the secondary magnet 52 in the axis direction of the shaft 31 .
  • the magnetic sensor 51 has a magnetoresistive (MR) element and detects a magnetic field parallel to the magnetic sensor 51 .
  • the magnetic sensor 51 has a magnetic detection surface and outputs a signal, indicative of a change in magnetic flux density on the magnetic detection surface, to the signal board 56 .
  • MR magnetoresistive
  • the signal board 56 calculates a relative rotation angle of the rotor 30 with respect to the stator 20 based on the signal outputted from the magnetic sensor 51 .
  • the signal board 56 outputs a signal, indicative of the calculated relative rotation angle, to the power substrate 61 through the connector 58 .
  • the power board 61 includes power transistors Q 1 , Q 2 , Q 3 , Q 4 , Q 5 , and Q 6 .
  • the power board 61 controls the power transistors Q 1 , Q 2 , Q 3 , Q 4 , Q 5 , and Q 6 based on the signal outputted from the signal board 56 , thereby supplying electrical power of a power source 62 to the winding set 22 .
  • the stator 20 generates a magnetic field rotating in the circumferential direction, and the rotor 30 rotates according to the magnetic field.
  • sixth tooth portions 29 are provided for every magnetic pole pair. That is, the rotating electrical machine 1 according to the first embodiment is characterized in that the number of tooth portions 29 for every magnetic pole pair is even. A difference between when the number of tooth portions for every magnetic pole pair is even and when the number of tooth portions for every magnetic pole pair is odd is described below with reference to FIGS. 4A and 4B .
  • FIG. 4A is a diagram illustrating a cross-sectional view of a rotating electrical machine 300 , as a reference example, in which the number of tooth portions for every magnetic pole pair is two, i.e., even
  • FIG. 4B is a diagram illustrating a cross-sectional view of a rotating electrical machine 400 , as a reference example, in which the number of tooth portions for every magnetic pole pair is one, i.e., odd.
  • a magnetic flux B from the top to the bottom of FIG. 4A is generated in a tooth portion 891 and a tooth portion 892 which is positioned at an electrical angle of n (i.e.,) 180° with respect to the tooth portion 891 .
  • n i.e., 180° with respect to the tooth portion 891 .
  • a magnetic field created by the magnetic flux B acts on a rotor 90 , which is located inside a stator 80 , without dispersion.
  • attraction force of the stator 80 on primary magnets 91 and 92 is increased so that the rotor 90 can be accurately and stably positioned with respect to the stator 80 as shown in FIG. 4A .
  • the tooth portion 112 is positioned at an angle of 60° with respect to the tooth portion 111
  • the tooth portion 113 is positioned at an angle of ⁇ 60° with respect to the tooth portion 111 . Therefore, it can be considered that the magnet flux B generated in a slot 114 between the tooth portion 112 and the tooth portion 113 is a half of the magnet flux B generated in the tooth portion 111 . Accordingly, attraction force of a stator 110 on primary magnets of a rotor 120 is reduced. Therefore, as indicated by a broken line in FIG. 4B , even when the rotor 120 is accurately positioned with respect to the stator 110 once, the rotor 120 may be displaced with respect to the stator 110 upon application of accidental external force.
  • the rotating electrical machine 1 can have the same advantage as the rotating electrical machine 300 shown in FIG. 4A . That is, when an electric current flows though the W-phase winding of the winding set 22 , the magnetic flux B is generated in the tooth portions 291 , 292 , and 293 in the radial inward direction so that the tooth portions 291 , 292 , and 293 can be magnetized, and the magnetic flux B is generated in the tooth portions 294 , 295 , and 296 in the radial outward direction so that the tooth portions 294 , 295 , and 296 can be magnetized opposite to the tooth portions 291 , 292 , and 293 .
  • the primary magnet 41 facing the tooth portions 291 , 292 , and 293 is a south pole
  • the primary magnet 42 facing the tooth portions 294 , 295 , and 296 is a north pole.
  • the secondary magnet 52 When the secondary magnet 52 is fixed to the shaft 31 in assembling of the rotating electrical machine 1 , the primary magnet 41 is positioned to face the tooth portion 292 , and the primary magnet 42 is positioned to face the tooth portion 295 by passing an electric current through the U-phase winding. In such an approach, the secondary magnet 52 can be fixed in a correct position with respect to the primary magnets 41 , 42 , 43 , 44 , 45 , 46 , 47 , and 48 . Thus, a rotational position of the rotor 30 (i.e., a relative rotation angle of the rotor 30 with respect to the stator 20 ) can be accurately detected.
  • the rotor 30 can be positioned in a predetermined position by passing a small amount of an electric current through the U-phase winding. Therefore, the power board 61 , which controls energization, can be reduced in size.
  • the secondary magnet 52 is fixed in a correct position with respect to the primary magnets 41 , 42 , 43 , 44 , 45 , 46 , 47 , and 48 , a process of adjusting detection accuracy in assembling of the rotating electrical machine 1 can be simplified. Thus, the number of man-hours required to assemble the rotating electrical machine 1 can be reduced.
  • the winding set 22 is wound on the tooth portions 29 at intervals of an electrical angle of n. That is, the winding set 22 is wound on the tooth portions 29 at intervals of an electrical angle equal to or greater than ⁇ (2k+1) ⁇ n/3k ⁇ , where k is the number of tooth portions 29 for every magnetic pole and every phase.
  • the stator 20 generates a strong magnetic field having opposite magnetic polarity at a position of an electrical angle of n.
  • the rotor 30 can be accurately positioned in a predetermined position. Therefore, the secondary magnet 52 can be fixed in a correct position, and the rotational position of the rotor 30 can be accurately detected accordingly.
  • the number of tooth portions 29 facing any one of the primary magnets 41 , 42 , 43 , 44 , 45 , 46 , 47 , and 48 is three. That is, the number of tooth portions 29 facing any one of the primary magnets 41 , 42 , 43 , 44 , 45 , 46 , 47 , and 48 is not less than (3k ⁇ 1). In such an approach, force enough to attract the primary magnets 41 , 42 , 43 , 44 , 45 , 46 , 47 , and 48 of the rotor 30 can be surely generated. Thus, the secondary magnet 52 can be fixed in a correct position, and the rotational position of the rotor 30 can be accurately detected accordingly.
  • a rotating electrical machine 2 according to a second embodiment of the present disclosure is described below with reference to FIG. 5 .
  • a difference between the first embodiment and the second embodiment is in a shape of a rotor.
  • the rotating electrical machine 2 is a reluctance motor including a salient-pole rotor 70 with no permanent magnet.
  • the rotor 70 includes a boss portion 700 , four projections 701 , 703 , 705 , and 707 (as a first magnetic pole), and four recesses 702 , 704 , 706 , and 708 (as a second magnetic pole).
  • the projections 701 , 703 , 705 , and 707 project from the boss portion 700 in a radial outward direction.
  • Each of the recesses 702 , 704 , 706 , and 708 is located between adjacent two of the projections 701 , 703 , 705 , and 707 , respectively.
  • the recess 702 is located between the projections 701 and 703 .
  • each of the projections 701 , 703 , 705 , and 707 has a length L 1 in a circumferential direction
  • each of the recesses 702 , 704 , 706 , and 708 has a length L 2 in the circumferential direction.
  • the length L 1 is not greater than the length L 2 .
  • a distance between a tip of the tooth portion 29 and each of the projections 701 , 703 , 705 , and 707 in a radial inward direction is smaller than a distance between a tip of the tooth portion 29 and each of the recesses 702 , 704 , 706 , and 708 in the radial inward direction.
  • a magnetic reluctance becomes smaller between the tip of the tooth portion 29 and each of the projections 701 , 703 , 705 , and 707 in the radial inward direction than between the tip of the tooth portion 29 and each of the recesses 702 , 704 , 706 , and 708 in the radial inward direction.
  • the rotor 70 has magnetic projections and recesses.
  • a position of the rotor 70 depends on a positional relationship between the tooth portion 29 and each of the projections 701 , 703 , 705 , and 707 which allow a magnetic flux to pass through easily. Therefore, the rotor 70 can be accurately positioned in a predetermined position.
  • a magnetic circuit in the rotating electrical machine 2 is optimized by setting the length L 1 to a value not greater than the length L 2 .
  • the rotating electrical machine 2 can be reduced in size.
  • a rotating electrical machine 3 according to a third embodiment of the present disclosure is described below with reference to FIG. 6 .
  • a difference between the first embodiment and the third embodiment is in a shape of a rotor.
  • the rotating electrical machine 3 is a consequent-pole motor.
  • a rotor 73 includes a boss portion 730 , four projections 731 , 733 , 735 , and 737 (as a first magnetic pole), four recesses 732 , 734 , 736 , and 738 , and four primary magnets 741 , 742 , 743 , and 744 (as a second magnetic pole).
  • the projections 731 , 733 , 735 , and 737 project from the boss portion 730 in a radial outward direction.
  • Each of the recesses 732 , 734 , 736 , and 738 is located between adjacent two of the projections 731 , 733 , 735 , and 737 , respectively.
  • the recess 732 is located between the projections 731 and 733 .
  • the primary magnets 741 , 742 , 743 , and 744 are placed on the recesses 732 , 734 , 736 , and 738 , respectively.
  • Each of the projections 731 , 733 , 735 , and 737 is made from soft magnetic material and has one of a north pole and a south pole.
  • Each of the primary magnets 741 , 742 , 743 , and 744 has the other of a north pole and a south pole.
  • each of the projections 731 , 733 , 735 , and 737 has a south pole, and each of the primary magnets 741 , 742 , 743 , and 744 has a north pole.
  • each of the projections 731 , 733 , 735 , and 737 has a length L 3 in a circumferential direction
  • each of the recesses 732 , 734 , 736 , and 738 has a length L 4 in the circumferential direction.
  • the length L 3 is not greater than the length L 4 .
  • the magnetic permeability of the projections 731 , 733 , 735 , and 737 is greater than the magnetic permeability of the primary magnets 741 , 742 , 743 , and 744 .
  • a magnetic reluctance becomes smaller between a tip of the tooth portion 29 and each of the projections 731 , 733 , 735 , and 737 in the radial inward direction than between the tip of the tooth portion 29 and each of the primary magnets 741 , 742 , 743 , and 744 in the radial inward direction. That is, the rotor 73 has magnetic projections and recesses.
  • a position of the rotor 73 depends on a positional relationship between the tooth portion 29 and each of the projections 731 , 733 , 735 , and 737 which allow a magnetic flux to pass through easily. Therefore, the rotor 73 can be accurately positioned in a predetermined position.
  • a magnetic circuit in the rotating electrical machine 3 is optimized by setting the length L 3 to a value not greater than the length L 4 .
  • the rotating electrical machine 3 can be reduced in size.
  • a rotating electrical machine 4 according to a fourth embodiment of the present disclosure is described below with reference to FIG. 7 .
  • a difference between the third embodiment and the fourth embodiment is in the number of tooth portions of a stator.
  • the rotating electrical machine 4 is a three-phase, eight-pole brushless motor.
  • a stator 75 has forty-eight tooth portions 76 .
  • a slot 74 is formed between adjacent tooth portions 76 .
  • a winding set 77 is wound in every sixth slot 74 . That is, the winding set 77 is wound at intervals of six slots 74 . In other words, the winding set 77 is wound at intervals of six tooth portions 76 .
  • the six tooth portions 76 providing each interval are positioned to face one primary magnet or one projection of the rotor 73 .
  • the winding set 77 is wound on the tooth portions 76 at intervals of an electrical angle of n (i.e.,) 180°.
  • FIG. 7 shows a direction of an electric current flowing through a U-phase winding only.
  • the number of tooth portions 76 for every magnetic pole pair is twelve.
  • each of the projections 731 , 733 , 735 , and 737 of the rotor 73 is positioned to face the six tooth portions 76 .
  • the secondary magnet 52 can be fixed in a correct position with respect to the projections 731 , 733 , 735 , and 737 and the primary magnets 741 , 742 , 743 , and 744 .
  • the rotational position of the rotor 73 can be accurately detected.
  • a rotating electrical machine 6 according to a fifth embodiment of the present disclosure is described below with reference to FIGS. 8 and 9 .
  • a difference between the first embodiment and the fifth embodiment is in a position where a magnetic sensor is fixed.
  • the rotating electrical machine 6 has three magnetic sensors 781 , 782 , and 783 (as a magnetic detector).
  • the magnetic sensors 781 , 782 , and 783 are located in a radial direction of the secondary magnet 52 . As shown in FIG. 9 , the magnetic sensors 781 , 782 , and 783 are spaced from each other by an angle of 30° around the rotation axis ⁇ of the shaft 31 .
  • the magnetic sensor 781 has a Hall element and detects a magnetic field perpendicular to the magnetic sensor 781 .
  • the magnetic sensor 782 has a Hall effect element and detects a magnetic field perpendicular to the magnetic sensor 782 .
  • the magnetic sensor 783 has a Hall effect element and detects a magnetic field perpendicular to the magnetic sensor 783 .
  • the total number of tooth portions is twenty-four, and the number of tooth portions for every magnetic pole is three. In the fourth embodiment, the total number of tooth portions is forty-eight, and the number of tooth portions for every magnetic pole is six.
  • the total number of tooth portions and the number of tooth portions for every magnetic pole are not limited to these numbers, as long as the number of tooth portions for every magnetic pole is even.
  • the rotating electrical machine is a three-phase brushless motor.
  • the number of phases of the rotating electrical machine is not limited to three.
  • the number of phases of the rotating electrical machine can be two.
  • the rotating electrical machine has eight poles.
  • the number of poles is not limited to eight.
  • the rotating electrical machine can have two poles.
  • the winding set is wound at intervals of an electrical angle of n (i.e.,) 180°.
  • the interval at which the winding set is wound is not limited to the electrical angle of n.
  • the winding set can be wound at intervals of an electrical angle smaller than ⁇ (2k+1) ⁇ n/3k ⁇ , where k is the number of tooth portions for every magnetic pole and every phase.
  • three magnetic sensors are located in a radial direction of the secondary magnet and spaced from each other by an angle of 30° around the rotation axis of the shaft.
  • the number of magnetic sensors and the angle by which the magnetic sensors are spaced from each other are not limited to those of the fifth embodiment.
  • only one magnetic sensor can be located in a radial direction of the secondary magnet.
  • the magnetic sensors can be spaced from each other by an angle different from 30°.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Brushless Motors (AREA)
  • Iron Core Of Rotating Electric Machines (AREA)
  • Permanent Magnet Type Synchronous Machine (AREA)
US13/935,715 2012-07-09 2013-07-05 Rotating electrical machine Abandoned US20140009044A1 (en)

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JP2012153596A JP5672507B2 (ja) 2012-07-09 2012-07-09 回転電機
JP2012-153596 2012-07-09

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US20170019007A1 (en) * 2014-08-01 2017-01-19 Panasonic Intellectual Property Management Co., Ltd. Motor
US10404142B2 (en) * 2014-02-04 2019-09-03 Hitachi Automotive Systems, Ltd. Motor control apparatus and power steering apparatus
WO2019190362A1 (en) * 2018-03-26 2019-10-03 Almofadda Mohammad Mechanical magnetic engine
US11015564B2 (en) * 2018-04-24 2021-05-25 GM Global Technology Operations LLC Starter for an internal combustion engine
US20210391773A1 (en) * 2018-10-23 2021-12-16 Safran Electronics & Defense Electric machine with more precise measurement
CN117411248A (zh) * 2023-10-10 2024-01-16 山西省机电设计研究院有限公司 超高精度伺服电机及电气设备

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WO2018180037A1 (ja) * 2017-03-31 2018-10-04 日本電産株式会社 モータ及び電動パワーステアリング装置
JP7151105B2 (ja) * 2018-03-08 2022-10-12 Tdk株式会社 磁石構造体、回転角度検出器、及び電動パワーステアリング装置

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Publication number Priority date Publication date Assignee Title
US10404142B2 (en) * 2014-02-04 2019-09-03 Hitachi Automotive Systems, Ltd. Motor control apparatus and power steering apparatus
US20170019007A1 (en) * 2014-08-01 2017-01-19 Panasonic Intellectual Property Management Co., Ltd. Motor
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WO2019190362A1 (en) * 2018-03-26 2019-10-03 Almofadda Mohammad Mechanical magnetic engine
US11015564B2 (en) * 2018-04-24 2021-05-25 GM Global Technology Operations LLC Starter for an internal combustion engine
US20210391773A1 (en) * 2018-10-23 2021-12-16 Safran Electronics & Defense Electric machine with more precise measurement
US11929650B2 (en) * 2018-10-23 2024-03-12 Safran Electronics & Defense Electric machine with more precise measurement
CN117411248A (zh) * 2023-10-10 2024-01-16 山西省机电设计研究院有限公司 超高精度伺服电机及电气设备

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US20170040876A1 (en) 2017-02-09
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CN103546011A (zh) 2014-01-29
US9929629B2 (en) 2018-03-27
CN103546011B (zh) 2017-08-15

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