Motor

Patent metadata

Field	Value
Publication number	US-12081065-B2
Application number	US-202117759112-A
Country	US
Kind code	B2
Filing date	Feb 4, 2021
Priority date	Feb 7, 2020
Publication date	Sep 3, 2024
Grant date	Sep 3, 2024

Abstract

A motor capable of increasing cogging torque is provided. A motor includes a shaft; a magnetic member including a core including an annular portion and a plurality of spokes and a coil; and a magnet, wherein one of the magnetic member and the magnet is disposed at an inner side of the other; an end portion of each of the spokes and the magnet oppose one another in radial directions nm; the core includes a pair of magnetic pole portions at the end portion of each of the spokes, the a pair of magnetic pole portions extending in both directions of circumferential directions xy; and of the pair of magnetic pole portions of at least one spoke from among the plurality of spokes, the magnetic pole portion at an x side has a larger magnetic resistance than the magnetic pole portion at a y side.

First claim

The invention claimed is:

1. A motor comprising:
a shaft;
a magnetic member including a plurality of spokes extending from the shaft in a radial direction, and plurality of coils wound around the plurality of spokes; and
a magnet disposed in an annular shape, wherein
one of the magnetic member and the magnet is disposed inside the other of the magnetic member and the magnet in the radial direction;
end portions of the plurality of spokes oppose the magnet in the radial direction;
each end portions of the plurality of spokes includes a pair of magnetic pole portions extending in opposite directions in a circumferential direction and a surface opposing the magnet; and
the plurality of spokes include a first spoke and a second spoke and a third spoke, the second spoke being arranged in an one magnetic pole portion side of the pair of magnetic pole portions of the first spoke in the circumferential direction, the third spoke being arranged in another magnetic pole portion side of the pair of magnetic pole portions of the first spoke in the circumferential direction,
a magnetic resistance at the one magnetic pole portion of the first spoke is larger than a magnetic resistance at the another magnetic pole portion of the first spoke,
a groove portion is formed at the surface of the end portion of the first spoke located on the second spoke side with respect to the first spoke,
a magnetic resistance at the another magnetic pole portion of the second spoke is larger than a magnetic resistance at the one magnetic pole portion of the second spoke,
a groove portion is formed at the surface of the end portion of the second spoke located on the first spoke side with respect to the second spoke,
magnetic resistances at a pair of magnetic pole portions of the third spoke is substantially equal,
the surface of the end portion of the third spoke includes a groove portion located at a center of the third spoke in the circumferential direction,
the number of the plurality of spokes is an even number,
among the plurality of spokes, other spoke at a position point-symmetric to the first spoke with respect to the shaft is defined as a fourth spoke, and other spoke at a position point-symmetric to the second spoke with respect to the shaft is defined as a fifth spoke;
a magnetic resistance at one magnetic pole portion of the fourth spoke is larger than a magnetic resistance at another magnetic pole portion of the fourth spoke,
a magnetic resistance at another magnetic pole portion of the fifth spoke is larger than a magnetic resistance at one magnetic pole portion of the fifth spoke.

2. A motor comprising:
a shaft;
a magnetic member including a plurality of spokes extending from the shaft in a radial direction,
a magnet disposed in an annular shape, wherein
and plurality of coils wound around the plurality of spokes, wherein
one of the magnetic member and the magnet is disposed inside the other of the magnetic member and the magnet in the radial direction;
end portions of the plurality of spokes oppose the magnet in the radial direction;
each end portions of the plurality of spokes includes a pair of magnetic pole portions extending in opposite directions in a circumferential direction and a surface opposing the magnet; and
the plurality of spokes include a first spoke and a second spoke and a third spoke, the second spoke being arranged in an one magnetic pole portion side of the pair of magnetic pole portions of the first spoke in the circumferential direction, the third spoke being arranged in another magnetic pole portion side of the pair of magnetic pole portions of the first spoke in the circumferential direction,
a magnetic resistance at the one magnetic pole portion of the first spoke is larger than a magnetic resistance at the another magnetic pole portion of the first spoke,
a magnetic resistance at the another magnetic pole portion of the second spoke is larger than a magnetic resistance at the one magnetic pole portion of the second spoke,
magnetic resistances at a pair of magnetic pole portions of the third spoke is larger than the magnetic resistance at the another magnetic pole portion of the first spoke and smaller than the magnetic resistance at the one magnetic pole portion of the first spoke,
among the plurality of spokes, other spoke at a position point-symmetric to the first spoke with respect to the shaft is defined as a fourth spoke, and other spoke at a position point-symmetric to the second spoke with respect to the shaft is defined as a fifth spoke;
a magnetic resistance at one magnetic pole portion of the fourth spoke is larger than a magnetic resistance at another magnetic pole portion of the fourth spoke,
a magnetic resistance at another magnetic pole portion of the fifth spoke is larger than a magnetic resistance at one magnetic pole portion of the fifth spoke.

3. The motor according to claim 2 , wherein
a pair of magnetic pole portions of the third spoke is substantially equal.

4. The motor according to claim 2 , wherein
the number of the plurality of spokes is an even number.

5. A motor comprising:
a shaft;
a magnetic member including a plurality of spokes extending from the shaft in a radial direction,
a magnet disposed in an annular shape, wherein
and plurality of coils wound around the plurality of spokes, wherein
one of the magnetic member and the magnet is disposed inside the other of the magnetic member and the magnet in the radial direction;
end portions of the plurality of spokes oppose the magnet in the radial direction;
each end portions of the plurality of spokes includes a pair of magnetic pole portions extending in opposite directions in a circumferential direction and a surface opposing the magnet; and
the plurality of spokes include a first spoke and a second spoke and a third spoke, the second spoke being arranged in an one magnetic pole portion side of the pair of magnetic pole portions of the first spoke in the circumferential direction, the third spoke being arranged in another magnetic pole portion side of the pair of magnetic pole portions of the first spoke in the circumferential direction,
a groove portion is formed at the surface of the end portion of the first spoke located on the second spoke side with respect to the first spoke,
a groove portion is formed at the surface of the end portion of the second spoke located on the first spoke side with respect to the second spoke,
the surface of the end portion of the third spoke includes a groove portion located at a center of the third spoke in the circumferential direction,
among the plurality of spokes, other spoke at a position point-symmetric to the first spoke with respect to the shaft is defined as a fourth spoke, and other spoke at a position point-symmetric to the second spoke with respect to the shaft is defined as a fifth spoke;
a magnetic resistance at one magnetic pole portion of the fourth spoke is larger than a magnetic resistance at another magnetic pole portion of the fourth spoke,
a magnetic resistance at another magnetic pole portion of the fifth spoke is larger than a magnetic resistance at one magnetic pole portion of the fifth spoke.

6. The motor according to claim 5 , wherein
the number of the plurality of spokes is an even number.

Assignees

• Minebea Mitsumi Inc

Inventors

• OHBA Hirofumi
• Kameoka Kodai

Classifications

• H02K15/085

  by laying conductors into slotted stators · CPC title

• H02K15/026

  Wound cores · CPC title

• H02K2201/03

  Machines characterised by aspects of the air-gap between rotor and stator · CPC title

• H02K1/165 Primary

  Shape, form or location of the slots · CPC title

• H02K1/24 Primary

  Rotor cores with salient poles {; Variable reluctance rotors} · CPC title