Axial flux electrical motor assembly and methods of assembling the same

A method of assembling an electric motor, said method comprising:

• coupling a rotor hub to a rotor disk to form a rotor assembly;
• slidably coupling the rotor hub to an axially-knurled shaft at a first position;
• coupling a stator assembly to the shaft proximate the rotor assembly;
• measuring a back EMF constant of the electric motor when the rotor assembly is in the first position;
• and
• sliding the rotor assembly along the shaft to a second position where a measured back EMF constant at the second position is substantially equal to a predetermined back EMF constant.

A rotor assembly for use in an axial flux electric motor having a stator assembly, said rotor assembly comprising:

• a shaft extending along an axis of rotation;
• a rotor hub slidably coupled to said shaft, wherein said shaft extends through a first central opening of said rotor hub;
• and
• a rotor disk fixedly coupled to said rotor hub, wherein at least a portion of said rotor hub extends through a second central opening of said rotor disk, and wherein said rotor hub and said rotor disk are slidable along said shaft from a first position on said shaft to a second position on said shaft with respect to the stator assembly based on a measured back EMF constant.