An electric motor includes a housing with a tubular wall extending in an axial direction of the housing and a closures positioned at opposite axial ends of the tubular wall, a stator fixedly mounted inside of the housing, a rotor rotatably mounted inside of the housing, and a bearing rotatably supporting the rotor. At least one of the closures includes a rotor supporting portion. The rotor supporting portion includes a through hole configured to receive a portion of the rotor. The through hole is defined by a closed shape including at least three or more straight sides, and a radius of an inscribed circle of the closed shape of the through hole is larger than a radius of the portion of the rotor received in the through hole.