Patent ID: 11863022
Assignee: NIDEC CORPORATION
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A motor comprising:
a rotor that has a rotor core and a rotor magnet fixed to the rotor core and is rotatable about a central axis;
a stator located on a first side in a radial direction of the rotor; and
a magnetic sensor configured to detect a magnetic field of the rotor magnet,
wherein
the rotor magnet has a plurality of magnetized portions arranged along a circumferential direction in a Halbach array to increase a magnetic field intensity on the first side in the radial direction,
the plurality of magnetized portions include:
a plurality of radially magnetized portions whose magnetization direction is the radial direction; and
a plurality of non-radially magnetized portions whose magnetization direction is different from the radial direction,

the plurality of radially magnetized portions include a first radially magnetized portion and a second radially magnetized portion, wherein magnetic poles on both sides in the radial direction of the second radially magnetized portion are arranged opposite to magnetic poles on both sides in the radial direction of the first radially magnetized portion,
the first radially magnetized portion and the second radially magnetized portion are alternately arranged along the circumferential direction with at least one of the plurality of non-radially magnetized portions interposed between the first radially magnetized portion and the second radially magnetized portion,
the magnetic sensor is located on a second side in the radial direction with respect to the rotor magnet,
a non-magnetized portion is provided in an axial portion of the rotor magnet where a magnetic field is detected by the magnetic sensor, and
the non-magnetized portion overlaps the first radially magnetized portion and the second radially magnetized portion in the circumferential direction.