Classifications

• • 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
  • H02K1/276—Magnets embedded in the magnetic core, e.g. interior permanent magnets [IPM]
  • H02K1/2766—Magnets embedded in the magnetic core, e.g. interior permanent magnets [IPM] having a flux concentration effect
• • 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
  • H02K1/28—Means for mounting or fastening rotating magnetic parts on to, or to, the rotor structures
• • 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
  • H02K1/276—Magnets embedded in the magnetic core, e.g. interior permanent magnets [IPM]
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K15/00—Processes or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines
  • H02K15/02—Processes or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines of stator or rotor bodies
  • H02K15/03—Processes or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines of stator or rotor bodies having permanent magnets
• • 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
  • H02K7/04—Balancing means
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K2201/00—Specific aspects not provided for in the other groups of this subclass relating to the magnetic circuits
  • H02K2201/03—Machines characterised by aspects of the air-gap between rotor and stator
• • 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
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T10/00—Road transport of goods or passengers
  • Y02T10/60—Other road transportation technologies with climate change mitigation effect
  • Y02T10/64—Electric machine technologies in electromobility

Definitions

• the present disclosure relates to electric motors and more specifically to the configuration of a rotor in an electric motor.
• the present disclosure relates to electric motors.
• the electric motor assembly includes a rotor mounted coaxially on a shaft.
• the rotor may include a center lamination stack mounted on a balance ring.
• the center lamination stack may have slots along the outer circumference that hold pole pieces coupled with a plurality of magnets.
• the magnets may be situated between the pole pieces and the center lamination stack.
• the pole pieces may further comprise fixturing slots, such that a plurality of embedded locating dowels which protrude from the surface of the balance ring can secure the pole pieces during a sleeve winding process in one embodiment.
• the described components of the rotor are encased in a wound fiber sleeve that holds the pole pieces in place around the periphery of the rotor.
• the rotor is rotably mounted within a stator to form a permanent magnet motor.
• FIG. 1 shows an example partial axial cross section of an electric motor, according to certain embodiments of the present disclosure.
• FIG. 2 illustrates a perspective view of a sleeved rotor, according to certain embodiments of the present disclosure.
• FIG. 3 illustrates a perspective view of the components of a rotor contained within a rotor sleeve, according to certain embodiments of the present disclosure.
• FIG. 4 illustrates an exemplary axial view of a sleeved rotor, according to certain embodiments of the present disclosure.
• FIG. 5A shows an exploded view of the internal components of a rotor, according to certain embodiments of the present disclosure.
• FIG. 5B shows a perspective view of a balance ring and lamination stack assembly on a motor shaft, according to certain embodiments of the present disclosure.
• FIG. 6 illustrates a lateral cross section of a rotor, according to certain embodiments of the present disclosure.
• FIG. 7 illustrates a motor performance graph comparing motor speed to torque for both a conventional permanent magnet motor and a permanent magnet motor having a carbon sleeve according to certain embodiments of the present disclosure.
• Embodiments relate to a permanent magnet motor with a rotor having magnetic pieces disposed around the periphery of the rotor and held in place using a wound fiber wrap around the exterior circumference of the rotor.
• the wound fiber wrap may be made of carbon fiber or other fiber materials.
• the magnetic pieces are not held in the rotor using metallic components and the magnets are not fully enclosed within the rotor.
• the magnetic fields created by a stator acting on the magnetic pieces in the rotor may be stronger in comparison to conventional rotors with magnetic pieces embedded into metal because the wound fiber wrap and lack of metal components may provide a lower level of interference with the magnetic fields generated by the stator.
• FIG. 1 shows an axial cross-sectional view of a permanent magnet motor 100 in accordance with one embodiment of the present disclosure.
• the illustration provided in FIG. 1 is simplified for the sake of explanation, this view omitting windings and other components.
• a rotor 101 is surrounded by a stator 103.
• a plurality of windings (not shown) is disposed around each of the stator teeth 109.
• the windings are copper, but other materials are within the scope of the invention.
• the windings define a plurality of poles, for example, a three-phase, four pole design or a six pole design.
• the rotor 101 is encircled by the stator 103, the two being separated by an air gap 105.
• a shaft 107 is coupled to the rotor 101, the shaft 107 providing a means for coupling the motor 100 to various devices and mechanisms, such as an axle, a gearbox and the like within an electric vehicle.
• the air gap 105 between the stator 103 and rotor 101 is sized to obtain a desired level of magnetic inductance from the stator 103 onto the rotor 101.
• the air gap 105 also may affect the saturation levels and harmonic levels of the magnetic flux proximal the air gap 105. In general, the smaller the air gap 105, the stronger the magnetic flux between the stator 103 and rotor 101.
• a series of magnets 111A and 11 IB are disposed in a “V” shaped configuration around the periphery of the rotor 101.
• the configuration of the magnets 111A and 11 IB has an apex 117 positioned towards the shaft 107 and two arms 119A and 119B that point towards the stator 103.
• the end of each of the arms 119A and 119B is adjacent to an opening 120A and 120B which provides an empty space between the arms of the magnets and the air gap 105.
• This air pocket, or empty space allows the magnetic flux from the rotor into the stator with minimal loss of permanent magnet flux the magnets 111A and 11 IB are not embedded into a solid metal body of the rotor 101.
• magnets 111 A and 11 IB may be oriented and that the magnets 111A and 11 IB may be arranged differently in other embodiments.
• a wound fiber sleeve 115 is shown encircling the rotor to hold the magnets 111 A and 11 IB in place as the rotor 101 spins within the stator 103. It should be understood that other magnet configurations in which the magnets are not fully enclosed by the rotor may also reduce loss of permanent magnet flux.
• FIG. 2 shows an assembled rotor 101 in accordance with the invention.
• the rotor 101 is encased in the wound fiber sleeve 115, as opposed to traditional iron bridges.
• the shaft 107 is coupled to the rotor 101, providing a means for coupling the motor to various devices and mechanisms, such as an axle, a gearbox and the like within an electric vehicle.
• the wound fiber sleeve 115 comprises carbon fiber that is wound around the rotor while pre-tensioned.
• the sleeve has a thickness of 0.1-2 mm. In other embodiments, the sleeve has a thickness of 0.3, 0.4, 0.5, 1, 2, 3, 4, or 5 mm.
• the present wound fiber sleeve production method strives to minimize the thickness of the sleeve by subjecting the fiber to a relatively higher tension during the winding process.
• the fiber may be wound onto the rotor while being pre- tensioned.
• the fiber may be wound using a unique godet system having godet rolls that can wind fiber around the periphery of the rotor under tension with minimal damage to the fiber.
• FIG. 3 illustrates an exemplary embodiment of the fully assembled inner components of the rotor 101 (with the sleeve removed) in accordance with the present disclosure.
• the rotor 101 encircles the shaft 107 and comprises a balance ring 313 at the lower end, center lamination stack 305, pole pieces 307, and magnets 111A and 11 IB.
• the shaft 107 has a coaxial disc 315 protruding from the lower end of the shaft 301.
• the coaxial disc 315 has one or more flat segments (“flats”) 303 along its circumference.
• the flats 303 serve as a gripping area for filament winder equipment during rotor manufacture, specifically during the sleeve winding process wherein the filament winder equipment grips the shaft to rotate the rotor.
• the disc may not have flats 303 and may instead have other gripping features as appropriate for the filament winder equipment.
• the disc may not have flats or any other gripping features, such that the disc has an uninterrupted outer circumference. In this figure, the wound fiber sleeve is not shown surrounding the rotor 101.
• the center lamination stack 305 is mounted to the balance ring 313.
• the center lamination stack 305 has a plurality of slots 317 along its outer lateral edge that run the entire length of the center lamination stack 305.
• the pole pieces 307 each are coupled with a plurality of magnets 111. When assembled, the pole pieces 307 and magnets 311 fit into the slots 317 of the center lamination stack 305 such that the magnets 111 are pressed between the pole piece 307 and the center lamination stack 305. This can be seen more fully with reference to Figure 5 below. It should be noted that in some embodiments the pole pieces 307 and the center lamination stack 305 are not connected by a steel bridge or other metal component, as in conventional rotor designs.
• each pole piece 307 has a fixturing slot 309, which is configured to interlock with a locating dowel (not shown) in the balance ring.
• the fixturing slot 309 and locating dowel may serve as securing features during rotor manufacture.
• the magnets 111, pole pieces 307, and center lamination stack 305 are fixtured to each other during assembly. In such embodiments, the pole pieces 307 may not have fixturing slots 309. Given the high speed at which the rotor components spin during the sleeve winding process, the securing features may keep the pole pieces 307 close against the center lamination stack 305 during manufacturing.
• the sleeve winding process begins with placing the rotor of FIG. 3 onto a rotating mechanism that is connected to a filament tensioning system such as godet rolls.
• the tensioning system may include a spool of carbon fiber that runs through a bath of epoxy resin and is then wound onto the outer circumference of the rotor mechanism of FIG. 3 as it rotates in one direction.
• the tensioning system may apply resin onto the spool during the dispensing process. This system allows the sleeve to be wound across the length of the rotor in a predetermined pattern and with a predetermined number of fiber wrappings to create a particular thickness of sleeve.
• the sleeve which surrounds the rotor is not necessarily made of carbon fiber.
• Other similar materials may also be wound around the rotor and used to surround the rotor and maintain the positions of the pole pieces and magnets.
• other composites made from other types of fibers such as ceramic, fiberglass, polypropylene, polyethylene, polyetheretherketone (PEEK) and similar plastics may be embedded into a resin to form a durable material that can be used to form a tensioned sleeve around the rotor.
• PEEK polyetheretherketone
• a combination of materials may be used to make the sleeve, such as carbon fiber embedded into a plastic.
• FIG. 4 shows an axial cross-sectional view of a fully assembled rotor according to the present disclosure.
• the assembly is coaxial with the shaft 107, as illustrated by the shaft 107 running through the center of the rotor.
• the magnets 111A and 11 IB can be seen pressed flush against both the pole pieces 307 and center lamination stack 305.
• magnets placed on adjacent faces of a pole piece for example, a pair of magnets forming a “V” shaped configuration
• Each pole piece 307 may comprise the fixturing slot 309 that interlocks with a locating dowel so the pole piece 307 is secure during the winding process.
• the wound fiber sleeve 115 may encase the entire assembly.
• the locating dowel may not be necessary, and embodiments of a motor may not include any locating dowels or rods.
• FIG. 5 A shows a partial assembly of the rotor 101 according to the present disclosure.
• this partial assembly only the center lamination stack 305 and balance ring 313 have been mounted onto the shaft 107.
• locating dowels 507 are embedded in the balance ring 313 and protrude beyond the face of the balance ring 313.
• a set of locating dowels 507 may protrude a small distance from the face of the balance ring 313 that contacts the center lamination stack 305.
• FIG. 5B shows an exploded view of the inner assembly of a rotor, according to the present disclosure.
• FIG. 5B shows how the pole pieces 307 and magnets 111A and 11 IB may fit into a plurality of the slots 317 and couple with each other and the center lamination stack 305.
• the magnets 111A and 11 IB are fixtured to the pole pieces 307 but not the center lamination stack 305, as illustrated in FIG. 5B.
• each pole piece 307 is a similar length as the length of the center lamination stack 305.
• Each pole piece 307 may be coupled with two magnets 111A and 11 IB that are also of a similar length.
• the magnets 111 A and 11 IB may be shorter and more magnets 111 A and 11 IB can be used to occupy the length of the pole piece 307 to which they are coupled. In yet other embodiments, the magnets 111 A and 11 IB may be a different shape than the rectangular prism depicted in FIG. 5B.
• each pole piece 307 may comprise a fixturing slot 309 to secure the pole piece 307 to the balance ring 313.
• the fixturing slot 309 runs through the entire length of the pole piece 307.
• the fixturing slot 309 may end partway through the pole piece 307.
• the pole pieces 307 may have either one fixturing slot 309 running the length of the pole pieces 307, or the pole pieces 307 may have one fixturing slot 309 on each end of the pole piece 307, with each fixturing slot 309 terminating within the length of the pole piece 307.
• the pole pieces 307, magnets 111A and 11 IB, and the center lamination stack 305 may be fixtured to each other during manufacture, such that the assembly does not have fixturing slots 309 or locating dowels 507.
• FIG. 6 is half of a lateral cross section of a rotor, in accordance with the present disclosure. Addressing components starting from the shaft 107 and radiating outward, FIG. 6 shows the center lamination stack 305, the magnet 111A coupled with the pole piece 307, and the locating dowel 507 interlocked with the fixturing slot 309 in the pole piece 307. The entire assembly is mounted on the balance ring 313. This illustration shows how the locating dowel 507 may be embedded in the balance ring 313 and only protrudes from the surface of the balance ring 313 that contacts the rotor assembly.
• FIG. 7 compares torque generation of the disclosed sleeved motor against a conventional permanent magnet motor.
• the solid line 701 tracks the amount of torque generated at various speeds by the disclosed sleeved motor.
• the dotted line 703 represents the torque generated at the same speeds by a conventional permanent magnet motor.
• the sleeved motor can produce more torque than the conventional motor at the same speeds.
• the sleeved motor can have a higher peak torque because the elimination of ribs and bridges allows for greater fundamental flux.
• the sleeved motor can also produce more power than a conventional motor at the same speeds. Higher fundamental flux to slot harmonic ratios lead to greater motor efficiency at high speeds, at both low and high torque. Further, the carbon wrapped motor design can reduce or eliminate leakages, which allows for better utilization of an inverter current and leads to a peak power increase of up to 25% or more. At high speeds, the sleeved motor can generate more power as compared to a conventional motor without increasing the usage of permanent magnet.
• joinder references e.g., attached, affixed, coupled, connected, and the like
• joinder references are only used to aid the reader's understanding of the present disclosure, and may not create limitations, particularly as to the position, orientation, or use of the systems and/or methods disclosed herein. Therefore, joinder references, if any, are to be construed broadly. Moreover, such joinder references do not necessarily infer that two elements are directly connected to each other.

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Permanent Field Magnets Of Synchronous Machinery (AREA)
• Iron Core Of Rotating Electric Machines (AREA)

Priority Applications (8)

Applications Claiming Priority (2)

Publications (1)

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Cited By (20)

Families Citing this family (11)

Citations (6)

Family Cites Families (10)

• 2021
  • 2021-04-30 CN CN202180042308.0A patent/CN115917927A/zh active Pending
  • 2021-04-30 WO PCT/US2021/030276 patent/WO2021225902A1/en not_active Ceased
  • 2021-04-30 JP JP2022567034A patent/JP2023527675A/ja active Pending
  • 2021-04-30 KR KR1020227041900A patent/KR20230004834A/ko active Pending
  • 2021-04-30 US US17/923,204 patent/US20230179045A1/en active Pending
  • 2021-04-30 EP EP21727317.6A patent/EP4147329A1/en active Pending
  • 2021-04-30 AU AU2021268591A patent/AU2021268591A1/en active Pending
  • 2021-04-30 MX MX2022013839A patent/MX2022013839A/es unknown
  • 2021-04-30 CA CA3177304A patent/CA3177304A1/en active Pending

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