Patent ID: 11962192
Assignee: MITSUBISHI ELECTRIC CORPORATION
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  F | IPC F  H

Claim 9:
10. An electric motor comprising:
a rotor including at least one permanent magnet, a first rotor core having a first electrical steel sheet, and a second rotor core having a second electrical steel sheet, the rotor having a magnetic pole part formed by the at least one permanent magnet; and
a stator including a stator core and a winding fixed to the stator core, the stator being disposed outside the rotor, wherein
the first electrical steel sheet is located outside the stator core in an axial direction of the rotor,
the first electrical steel sheet includes
a first left flux barrier part and a first right flux barrier part respectively provided on both sides of the magnetic pole part in a circumferential direction of the rotor, in a plane perpendicular to the axial direction,
a first left bridge provided between the first left flux barrier part and an outer peripheral surface of the first rotor core, and
a first right bridge provided between the first right flux barrier part and the outer peripheral surface of the first rotor core,
the second electrical steel sheet includes
a second left flux barrier part and a second right flux barrier part respectively provided on both sides of the magnetic pole part in the circumferential direction, in the plane,
a second left bridge provided between the second left flux barrier part and an outer peripheral surface of the second rotor core, and
a second right bridge provided between the second right flux barrier part and the outer peripheral surface of the second rotor core, and
the electric motor satisfies

(BL1×tL1+BR1×tR1)>(BL2×tL2+BR2×tR2),

where BL1 is a minimum width of the first left bridge in the plane, tL1 is a thickness of the first left bridge in the axial direction, BR1 is a minimum width of the first right bridge in the plane, tR1 is a thickness of the first right bridge in the axial direction, BL2 is a minimum width of the second left bridge in the plane, tL2 is a thickness of the second left bridge in the axial direction, BR2 is a minimum width of the second right bridge in the plane, and tR2 is a thickness of the second right bridge in the axial direction, wherein
the at least one permanent magnet comprises two permanent magnets,
the first electrical steel sheet includes a first center bridge provided between the two permanent magnets,
the second electrical steel sheet includes a second center bridge provided between the two permanent magnets, and
the electric motor satisfies

(BL1×tL1+BR1×tR1+BC1×tC1)>(BL2×tL2+BR2×tR2+BC2×tC2),

where BC1 is a minimum width of the first center bridge in the plane, tC1 is a thickness of the first center bridge in the axial direction, BC2 is a minimum width of the second center bridge in the plane, and tC2 is a thickness of the second center bridge in the axial direction, wherein
the electric motor satisfies BL1=BL2=BR1=BR2=BC1=BC2, tL1>tL2, tR1>tR2, and tC1>tC2.