| 摘要 |
PROBLEM TO BE SOLVED: To solve a problem that the shaft voltage between an outer ring and an inner ring of a bearing contains high frequency components caused by switching, and when the shaft voltage reaches a dielectric breakdown voltage of oil film inside the bearing, minute current flows in the bearing and thus electric corrosion occurs in the bearing, so that progression of electric corrosion induces a wavy abrasion phenomenon in the bearing inner ring, the bearing outer ring or a bearing ball, and brings abnormal sounds.SOLUTION: A rotor of an electric motor has an outer iron core constituting an outer peripheral portion of the rotor, an inner iron core constituting an inner peripheral portion fastened to a shaft, and an insulation layer which is disposed between the outer iron core and the inner iron core and comprises a dielectric material, and the electrostatic capacitance between the outer iron core and the inner iron core can be adjusted.SELECTED DRAWING: Figure 1 |
