Rotor, motor, and electric power steering device

Abstract

A rotor includes a shaft extending in an axial direction, a rotor core including laminations stacked in the axial direction, and at least one caulking portion at a radial-directional inner side of at least one magnet to caulk the laminations to each other. At least one magnet is embedded in the rotor core. At least one fixing portion fixes at least portions of outer peripheral edges of the laminations to each other. The caulking portion, the at least one magnet, and the at least one fixing portion are all arranged to be intersected by a straight line which is on a flat two-dimensional plane extending in a radial direction and a circumferential direction.

What is claimed is: 
     
         1 . A rotor comprising:
 a shaft extending in an axial direction;   a rotor core including laminations stacked in the axial direction, and at least one caulking portion at a radial-directional inner side of at least one magnet to caulk the laminations to each other;   the at least one magnet embedded in the rotor core; and   at least one fixing portion fixing at least portions of outer peripheral edges of the laminations to each other; wherein   the caulking portion, the at least one magnet, and the at least one fixing portion are all arranged to be intersected by a straight line which is on a flat two-dimensional plane extending in a radial direction and a circumferential direction.   
     
     
         2 . The rotor of  claim 1 , wherein the at least one fixing portion is a welded portion at which the outer peripheral edges of the laminations are welded to each other. 
     
     
         3 . The rotor of  claim 1 , wherein the laminations define at least one lamination group, and the at least one caulking portion and the at least one fixing portion are provided for each lamination group. 
     
     
         4 . The rotor of  claim 3 , wherein the at least one lamination group includes multiple lamination groups deviated from each other in the circumferential direction. 
     
     
         5 . The rotor of  claim 1 , wherein the rotor core includes convexities protruding outward in the radial direction and disposed in the circumferential direction, a number of the at least one magnet and a number of the at least one fixing portion are the same as a number of the convexities, and the at least one fixing portion is at a vertex of one of the convexities. 
     
     
         6 . The rotor of  claim 5 , wherein the at least one lamination group includes multiple lamination groups and circumferential positions of each of the convexities in each of the lamination groups are different from each other. 
     
     
         7 . The rotor of  claim 1 , wherein the rotor core includes lightening holes penetrating the rotor core in the axial direction, a number of the at least one caulking portion is the same as a number of the lightening holes, and the lightening holes and the at least one caulking portion are alternately disposed in the circumferential direction. 
     
     
         8 . The rotor of  claim 7 , wherein the lightening holes in each of the lamination groups are in communication with each other. 
     
     
         9 . The rotor of  claim 1 , wherein a number of the at least one magnet, a number of the at least one caulking portion, and a number of the at least one fixing portion are the same. 
     
     
         10 . The rotor of  claim 1 , wherein
 the rotor core includes convexities protruding outward in the radial direction and provided in the circumferential direction;   an outer circumferential surface of the rotor core includes bases and the convexities;   the convexities protrude outward from the base in the radial direction;   when viewed in a plan view, an outer edge of the convexities have an arc or substantially arc shape;   a radius of curvature of at least one of the convexities is smaller than a radius of curvature of at least one of the bases; and   the at least one fixing portion is at a vertex of one of the convexities.   
     
     
         11 . The rotor of  claim 10 , wherein a circumferential length of the convexities is smaller than a circumferential length of the at least one magnet. 
     
     
         12 . A motor comprising;
 the rotor of  claim 1 ; and   a stator opposing the rotor in a radial direction and including coils.   
     
     
         13 . An electrical power steering device comprising the motor of  claim 12 , a steering shaft, and an axle.