Electric motor having an integrated cooling system and methods of cooling an electric motor

An electric propulsion system for an aircraft, the system comprising:

• an electric motor comprising a stator, a rotor, and a drive shaft operably coupled to the rotor;
• a motor cooling conduit that defines a pathway for conveying a cooling fluid through or around at least a portion of the electric motor, the motor cooling conduit having a thermally conductive relationship with the at least a portion of the electric motor;
• a casing assembly that circumferentially surrounds at least a portion of the electric motor, the casing assembly comprising:
• a motor casing;
• a nacelle;
• and
• a casing assembly conduit integrally formed within at least a portion of the casing assembly wherein the casing assembly conduit and the at least a portion of the casing assembly define a monolithic, single-piece construction, the casing assembly conduit defining a pathway for conveying the cooling fluid through the at least a portion of the casing assembly, and the casing assembly conduit having a thermally conductive relationship with an external surface of the casing assembly;
• and
• a pump or compressor operably coupled to the drive shaft, the pump or compressor being operably configured to circulate cooling fluid through the motor cooling conduit and the casing assembly conduit,
• wherein, during operation, airflow passes over the external surface of the casing assembly, thereby transferring heat to the airflow from the cooling fluid circulating through the casing assembly conduit by the thermally conductive relationship with the external surface of the casing assembly.

A method of cooling an electric machine used for propulsion of an aircraft, the method comprising:

• circulating a cooling fluid through a motor cooling conduit that defines a pathway for conveying a cooling fluid through or around at least a portion of an electric motor, the motor cooling conduit having a thermally conductive relationship with the at least a portion of an electric motor, the electric motor comprising a stator and a rotor;
• transferring heat from the electric motor to the cooling fluid circulating through the motor cooling conduit by the thermally conductive relationship with the at least a portion of the electric motor;
• and
• circulating the cooling fluid through a casing assembly conduit integrally formed within at least a portion of a casing assembly wherein the casing assembly conduit and the at least a portion of the casing assembly define a monolithic, single-piece construction, the casing assembly comprising a motor casing, a nacelle, and a plurality of support members circumferentially supporting the nacelle about the motor casing, the casing assembly conduit defining a pathway for conveying the cooling fluid through the at least a portion of the casing assembly, the casing assembly circumferentially surrounding at least a portion of the electric motor, and the casing assembly conduit having a thermally conductive relationship with an external surface of the casing assembly,
• wherein the cooling fluid is circulated through the motor cooling conduit and the casing assembly conduit at least in part by a pump or a compressor operably coupled to a drive shaft, the drive shaft operably coupled to the rotor of the electric motor.