Abstract: A rotor includes a rotor body and a plurality of permanent magnet received in the rotor body. The rotor body separately defines a plurality of recess troughs on an outer wall of the rotor body. Side surfaces of each recess trough include a bottom surface and two side surfaces. The bottom surface is coupled between the two side surfaces. The bottom surface is a planar surface, and each side surface is a curved surface. The rotor body further defines a plurality of receiving grooves around a circumferential direction of the rotor body and extends along the vertical axis of the rotor body. Each receiving groove receives at least one permanent magnet. Each two adjacent receiving grooves are positioned under one bottom surface, and sidewalls of each two adjacent receiving grooves and the corresponding one bottom surface cooperatively form a T-shaped region.