Patent ID: 11949293
Assignee: NIDEC CORPORATION
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A rotor used in an outer rotor motor, the rotor comprising:
a rotor holder in a tubular shape extending along a center axis;
a rotor core in a tubular shape extending in an axial direction and being fixed to a surface of the rotor holder, directed radially inward; and
permanent magnets that are bonded to an inner circumferential surface of the rotor core and positioned side by side in a circumferential direction; wherein
the rotor core is defined by a plurality of electromagnetic steel sheets laminated in a thickness direction and includes projection portions projecting radially inward from the inner circumferential surface of the rotor core;
the projection portions are defined by portions of the plurality of electromagnetic steel sheets, with only some of the plurality of electromagnetic steel sheets defining the projection portions;
one or more of the projection portions are located in a gap between ones of the permanent magnets that are adjacent to each other in the circumferential direction;
each of the projection portions has an axial length shorter than an axial length of each of the permanent magnets;
the rotor includes a lid extending radially inward from one end of the rotor in the axial direction;, among two of the projection portions which are spaced apart from one another in the axial direction, a projection portion that is farther from the lid has a shorter axial length than an axial length of a projection portion which is closer to the lid in the axial direction.