US Patent 7942651 Refrigeration device with improved DC motor

A miniature cooling device includes numerous improvements capable of increasing the reliability and useful lifetime of the device, as well as improving electrical power to cooling power conversion efficiency. The improvements include a DC motor shaft design that incorporates a flywheel mass 314 with a solid shaft cross-section 300 for increasing shaft stiffness and magnetic flux density in the DC motor. Additional improvements include a bend resistant flexible vane 1114 in the DC motor to compression piston drive coupler, and a sealed cover set configured to be removable to make a motor repair and then replaced.