Patent attributes
A pump includes a pump part provided with an impeller having a plurality of blades for sucking and discharging a liquid; a pump case accommodating the pump part; a rotor installed to the impeller to rotate the impeller; a motor part accommodating a stator disposed around an outer periphery of the rotor to drive the rotor and a driving circuit for controlling the stator; a partition member for isolating the motor part from the pump part to protect the motor part therefrom. The pump further includes a reservoir space disposed in the impeller; an extra passage provided between the rotor and the partition member and connected to the reservoir space to introduce the liquid thereto from the blades; and one or more reflux passages, formed at the impeller, for flowing the liquid in the reservoir space back to the blades.