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EP-4167438-B1 - FLUX CONCENTRATION ROTOR AND MOTOR HAVING THE SAME

EP4167438B1EP 4167438 B1EP4167438 B1EP 4167438B1EP-4167438-B1

Inventors

  • KIM, JAEHO
  • MIN, Younggeun
  • Lee, Jiwan
  • HA, KYUNGHO

Dates

Publication Date
20260506
Application Date
20220706

Claims (9)

  1. A flux concentrate type rotor comprising: a shaft (210); a rotor core (220); and at least one arc type permanent magnet (230, 230A, 230B) having an inner diameter portion (231) and an outer diameter portion (233), wherein the rotor core (220) includes: an annular ring-shaped inner diameter portion core (221) having a shaft through hole (221a) into which the shaft (210) is inserted, a plurality of outer diameter portion cores (223) arranged along a circumferential direction of the inner diameter portion core (221) on an outer circumferential surface of the inner diameter portion core (221), and spaced apart from each other to form permanent magnet insertion portions (223a) for accommodating the permanent magnets (230, 230A, 230B), and a plurality of bridges (225) arranged along the circumferential direction of the inner diameter portion core (221) to correspond to each of the outer diameter portion cores (223), and connect each of the outer diameter portion cores (223) to the inner diameter portion core (221), and wherein the outer diameter portion core (223) has a first cutout portion (223f) positioned at a lower end, wherein each outer diameter portion core (223) includes a first side (223d) in contact with an inner diameter portion (231) of a first permanent magnet (230A) of two adjacent permanent magnets (230) and a second side (223e) in contact with an outer diameter portion (233) of a second permanent magnet (230B) positioned opposite the first side (223d) of the two permanent magnets (230, 230A, 230B), and the first cutout portion (223f) is formed extending from an end of the second side (223e) of each outer diameter portion core (223) toward the first side (223d), wherein each bridge (225) includes a first side (225a) extending from an end of the first side (223d) of each outer diameter portion core (223) and connected to the inner diameter portion core (221), and a second side (225b) positioned opposite the first side (225a) of each bridge (225) and connected to the inner diameter portion core (221), and the second side (225b) of each bridge (225) is positioned spaced apart from the second side (223e) of each outer diameter portion core (223) toward the first side (223d) of each outer diameter portion core (223), wherein the inner diameter portion (231) of the first and second permanent magnets (230, 230A, 230B) are formed to have a first curvature (R1), and the outer diameter portion (233) of the first and second permanent magnets (230, 230A, 230B) are formed to have a second curvature (R2) different from the first curvature (R1), wherein the second curvature (R2) is greater than the first curvature (R1), wherein the first and second permanent magnets (230, 230A, 230B) further include a connecting portion (235) connecting an end of the inner diameter portion (231) and an end of the outer diameter portion (233), wherein the connecting portion (235) includes a first straight portion (235a) connected to the end of the outer diameter portion (233), and a second straight portion (235b) connecting an end of the first straight portion (235a) and the end of the inner diameter portion (231), and the first straight portion (235a) and the second straight portion (235b) have an interior angle of 90 degrees.
  2. The flux concentrate type rotor of claim 1, wherein a portion of the first side (225a) of each bridge (225) is in contact with at least a portion of the connecting portion (235) of the first permanent magnet (230A).
  3. The flux concentrate type rotor of claim 1 or 2, wherein the first cutout portion (223f) extends from a point where the first straight portion (235a) of the permanent magnet (230, 230A, 230B) and an lower end of the second side (223e) of each outer diameter portion core (223) are connected toward the first side (223d) of each outer diameter portion core (223), and the second side (225b) of each bridge (225) extends from an end of the first cutout portion (223f) and connects to the inner diameter portion core (221).
  4. The flux concentrate type rotor of claim 3, wherein a portion where the second side (225b) of each bridge (225) and the end of the first cutout portion (223f) are connected is positioned radially outward from the first straight portion (235a) of the first permanent magnet (230A), and the first cutout portion (223f) and the second side (225b) of each bridge (225) form an acute angle.
  5. The flux concentrate type rotor of claim 3, wherein the first cutout portion (223f) is parallel to at least a portion of the connecting portion (235) of the permanent magnet (230, 230A, 230B).
  6. The flux concentrate type rotor of claim 3, wherein each outer diameter portion core (223) further includes a second cutout portion (223g) extending radially outward from the end of the first cutout portion (223f), and the second side (225b) of each bridge (225) extends from an end of the second cutout portion (223g) and connects to the inner diameter portion core (221).
  7. The flux concentrate type rotor of claim 6, wherein a portion where the second side (225b) of each bridge (225) and the end of the second cutout portion (223g) are connected is positioned radially outward from the first straight portion (235a) of the first permanent magnet (230A), and the second cutout portion (223g) and the second side (225b) of each bridge (225) form an acute angle.
  8. The flux concentrate type rotor of claim 6, wherein the first cutout portion (223f) is formed parallel to at least a portion of the connecting portion (235) of the permanent magnet (230, 230A, 230B).
  9. A motor comprising the flux concentrate type rotor according to any one of the preceding claims.

Description

BACKGROUND OF THE INVENTION Field of the Invention The present disclosure relates to a flux concentrate type rotor and a motor having the same, in more detail, to a structure for reducing an amount of leakage flux in a flux concentrate rotor having an arc-type permanent magnet and a motor having the same. Description of the Related Art A motor is a machine that obtains rotational force from electrical energy, and includes a stator and a rotor. The rotor is configured to interact electromagnetically with the stator, and is rotated by a force acting between a magnetic field and a current flowing through a coil. The motor using a permanent magnet to generate a magnetic field is divided into a surface mounted motor and an interior permanent magnet motor based on the coupling structure of the permanent magnet installed in the rotor core. Here, a surface-attached motor is a type in which a permanent magnet is attached to the surface of the core of the rotor, and has relatively low noise and vibration and good rotational force, but has disadvantages in that the permanent magnet is detached during high-speed rotation, the mechanical rigidity is lowered, and the control for diversification of the operation area is not easy. In addition, the permanent magnet embedded motor is a type in which a permanent magnet is inserted and fixed through a buried hole penetrating up and down in the core, and has a characteristic that torque and output are increased by adding a reluctance torque by a silent pole structure to an electromagnetic torque than a conventional surface-attached motor. On the other hand, recently, a flux concentrate type rotor has been developed, which further improves motor efficiency by further improving torque and output than a permanent magnet embedded motor. The flux concentrate type rotor is also referred to as a spoke type motor. Since the flux concentrate type rotor has advantages that high torque and high output can be generated because the flux concentration is structurally high, and the rotor can be miniaturized for the same output, it can be applied to driving motors such as washing machines or electric vehicles that require high torque and high output characteristics. In general, the flux concentrate type rotor includes a permanent magnet radially disposed about a shaft, and a rotor core provided to support permanent magnets and form a path of flux. The rotor core may be configured to include yokes disposed between the respective permanent magnets, and a cylindrical base positioned between the shaft and the permanent magnets and connected to each of the yokes. On the other hand, in such a conventional flux concentrate type rotor, some of the flux may leak toward the shaft through the inner diameter portion core of the rotor core, if the leakage flux increases, the output inevitably decreases, compared to a rotor with the same output, since the use of permanent magnets increases, it is disadvantageous in terms of material cost and miniaturization of the rotor. Therefore, research for reducing the leakage flux in the flux concentrate type rotor is being conducted in various forms. As an example, Chinese Patent No. CN201580078448 (hereinafter, referred to as "Prior Patent 1") discloses a technique for reducing the leakage flux and reducing the weight of the rotor core by alternately stacking the first core layer and the second core layer to form the rotor core. Hereinafter, with reference to FIGS. 1 and 2, the prior patent 1 will be described. The flux concentrate type rotor provided in the motor of Prior Patent 1 comprises a shaft 1, a rotor core 2, and a permanent magnet 3 of a square bar type. The rotor core 2 is manufactured by laminating a plurality of thin steel plates, and has a structure in which a plurality of permanent magnets 3 can be inserted therein. In addition, the central portion of the inner diameter portion core 11 of the rotor core 2 has a hole through which the shaft 1 can pass. The shaft 1 is fixed at the central portion of the inner diameter portion core 11 of the rotor core 2 to rotate together with the rotor core 2. The rotor core 2 is formed by alternately stacking two different core layers, that is, a first core layer L1 and a second core layer L2. In this case, the first core layer L1 is disposed at the uppermost and lowermost ends of the rotor core 2. The first core layer L1 has a support protrusion pattern in which the support protrusions 14 for supporting the permanent magnet 3 on the side surface of the inner diameter portion core 11 appear discontinuously in the direction of the rotation axis, and the second core layer L2 has a space portion 21 to prevent contact with the shaft 1 by removing the inner diameter portion core 11. The rotor core composed of these first and second core layers L1 and L2 may reduce leakage flux, in particular, the leakage flux leaking toward the rotating shaft through the inner diameter portion core 11, and reduce the weight of the entire r