Air cooling apparatus

An air cooling apparatus comprising:

• an electric motor;
• an expander rotating by rotation power of the electric motor to expand air;
• an expander housing surrounding the expander;
• and a power transmission device interposed between the electric motor and the expander housing to increase rotational driving of the expander,
• wherein the power transmission device comprises a power generator driven by a magnetic field and a front driver module and a rear driver module disposed at the front and rear sides of the power generator to form a magnetic field around a front rotor and a rear rotor of the power generator, the power generator being mounted with the expander on a shaft of a bearing module, being mounted with the rear driver module and the expander housing spaced apart from the rear rotor by a predetermined gap in an axial direction of a frame and disposed in a direction orthogonal to the rear rotor at the rear side of the frame, the front side of the frame being mounted on the electric motor, and the front driver module being spaced from the front rotor by a predetermined gap in the axial direction of the frame and disposed in a direction orthogonal to the front rotor at the front side of the frame and being mounted on a shaft of the electric motor to receive rotation power of the electric motor, and
• the front rotor and the rear rotor of the power generator face the front driver module and the rear driver module, permanent magnets of the front rotor and the rear rotor having magnetic fluxes thereof facing the axial direction of the shaft, the permanent magnets of the front driver module and the rear driver module having magnetic fluxes thereof facing the axial diameter direction of the shaft such that a rotating magnetic field generated by rotation of the front driver module, a rotating magnetic field generated by the power generator and a magnetic field of the rear driver module form a rotational force with the interaction of an attractive force and a repulsive force to increase the revolution per minute and the rotational force and transfer power.