Selective permeability rotor sleeve for interior permanent magnet machine

A motor vehicle comprising:

• a radial flux electric motor configured to generate torque for propulsion of the motor vehicle, the radial flux electric motor including:
• a stator having a radially inner stator surface and stator windings arranged thereon;
• a rotor mounted inside the stator and configured to rotate relative thereto about a rotational axis, wherein the rotor has a rotor core defined by a rotor outer surface and includes magnetic poles configured to generate magnetic flux and defining flux leakage zones;
• and
• a selective permeability sleeve arranged circumferentially on the rotor and fixed to the rotor outer surface, thereby establishing an airgap between the sleeve and the stator, wherein the sleeve provides reinforcement to the rotor core and to the magnetic poles and includes regions of relatively high magnetic permeability and regions of relatively low magnetic permeability alternating around the rotor outer surface such that the regions of relatively low magnetic permeability are arranged radially outward and across from the flux leakage zones to control magnetic flux distribution in the electric motor.

A radial flux electric motor comprising:

• a stator having a radially inner stator surface and stator windings arranged thereon;
• a rotor mounted inside the stator and configured to rotate relative thereto about a rotational axis, wherein the rotor has a rotor core defined by a rotor outer surface and includes magnetic poles configured to generate magnetic flux and defining flux leakage zones;
• and
• a selective permeability sleeve arranged circumferentially on the rotor and fixed to the rotor outer surface, thereby establishing an airgap between the sleeve and the stator, wherein:
• the sleeve provides reinforcement to the rotor core and to the magnetic poles and includes regions of relatively high magnetic permeability and regions of relatively low magnetic permeability alternating around the rotor outer surface such that the regions of relatively low magnetic permeability are arranged radially outward and across from the flux leakage zones to control magnetic flux distribution in the electric motor;
• and
• each region of relatively high magnetic permeability is constructed from a ferromagnetic material and each region of relatively low magnetic permeability is constructed from a paramagnetic material.