ELECTRIC MOTOR AND ITS ROTOR, AND MAGNETIC CORE FOR THE ROTOR

摘要

Intended is to improve a magnetic flux density of the surface of a rotor. This rotor includes a first non-magnetic portion (13), a second non-magnetic portion (14) and a third non-magnetic portion (16), which are arranged on an axis (Q) from the end portion to the center of a permanent magnet burying hole (12). Further included is a fourth non-magnetic portion (15) between the second non-magnetic portion (14) and the third non-magnetic portion (16). An angle on the axis with reference to the position between the permanent magnet burying holes is determined, as follows. A position between the first non-magnetic portion and the second non-magnetic portion is expressed by a first angle (?7). A position between the third non-magnetic portion and the fourth non-magnetic portion is expressed by a second angle (2·?7), which is twice as large as the first angle. The end portion of the third non-magnetic portion on the magnetic pole center side is expressed by a third angle (?3). The first angle and the third angle have the values, which are calculated by dividing 360 degrees by a value of seven times and a value of three times as large as the number of the permanent magnet burying holes, respectively.