Abstract: A rotor for an electric motor may include a shaft extending along a rotation axis of the electric motor and a rotor core comprising a plurality of core blocks fixed to the shaft and arranged along the rotation axis. The plurality of core blocks may include a first core block and a second core block that are oriented differently from each other in a circumferential direction about the rotation axis. Each of the plurality of core blocks may include an outer surface extending along the circumferential direction, a center hole through which the shaft passes, and an outer groove defined in the outer surface. An inner surface of the center hole may be in continuous contact in the circumferential direction with an outer surface of the shaft over an entire circumference thereof.