PURPOSE: To obtain a motor in which the cooling performance is enhanced by cooling the rotor from the interior without fixing any fin to the rotor.
CONSTITUTION: Four through holes 24 are made up at the border of a rotor core 22 and a field permanent magnet 23 while extending axially from one end face toward the other end face. The through holes 24 are formed by making four grooves axially, at a constant interval, in the outer circumferential surface of the rotor core 22 and the inner circumferential surface of the permanent magnet 23 and then fitting the permanent magnet 23 to the outer circumference of the rotor core 22 while aligning the grooves on the rotor core 22 side and the permanent magnet 23 side. Since the rotor 20 is cooled from the interior thereof by the air flowing through the through hole, cooling performance is enhanced.
ITO HIROKI
OKADA KYOICHI
TOSHIBA CORP