Electric motor

Abstract

An electric motor according to the embodiment includes a rotor core 21, a stator core 11 provided so as to face the rotor core 21 in the radial direction, and permanent magnets 23 buried in the vicinity of an outer circumferential part of the rotor core 21, wherein the outer circumferential part of the rotor core 21 and an inner circumferential part of the stator core 11 are formed in such a manner that a radial gap length between the outer circumferential part of the rotor core 21 and the inner circumferential part of the stator core 11 for one magnetic pole of the permanent magnet 23 becomes a gap length along a gap length l regulated by an expression (1) capable of making magnetic flux density distribution between the outer circumferential part of the rotor core 21 and the inner circumferential part of the stator core 11 a sinusoidal waveform.

Description

technical field [0001] The disclosed embodiments relate to an electric motor. Background technique [0002] Conventionally, there is known a motor in which permanent magnets are embedded in the vicinity of the outer peripheral portion of the rotor core (for example, refer to Japanese Patent Application Laid-Open No. 2000-197292). [0003] The above publication discloses a permanent magnet type rotor of a permanent magnet type motor in which permanent magnets are embedded near the outer periphery of a rotor core (rotor core). In this permanent magnet type motor, a stator core (stator core) is provided so as to face a rotor core in a radial direction. In addition, in this permanent magnet type motor, the portion corresponding to one magnetic pole of the permanent magnet on the outer peripheral portion of the rotor core is formed into a shape consisting of one arc, so that the outer peripheral portion of the rotor core is aligned with the stator core. The distribution of the ...

AI Technical Summary

Problems solved by technology

[0004] However, in the permanent magnet type motor described in the above publication, since the portion of the outer peripheral portion of the rotor core corresponding to one magnetic pole of the permanent magnet is formed in a shape consisting of one arc, it is conceivable that it is relatively difficult to make the The distribution of the magnetic flux density between the outer circumference of the rotor core and the inner circumference of the stator core is closer to a sine wave

Therefore, in the above-mentioned Patent Document 1, since it is conceivable that it is difficult to further reduce the cogging torque or torque ripple while making the waveform of the induced voltage closer to a sine wave, there is a problem that it is difficult to further improve the performance of the motor.

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