Patent ID: 7766629

Claim:
A fluid pump comprising: a case having a pump chamber defined by a bottom perpendicular to an axial direction and a circumferential surface parallel to the axial direction; a suction port and a discharge port both provided in the circumferential surface so as to communicate with the pump chamber; an impeller rotatably mounted in the pump chamber, the impeller, when rotated, sucking a fluid into the pump chamber via the suction port and discharging the fluid out of the pump chamber via the discharge port, the impeller having a disc-shaped portion having a flat region opposed to the bottom, the flat region being provided with a plurality of pump vanes protruding toward the bottom of the pump chamber, the pump vanes being arranged so as to extend radially from near a center of the flat surface near to a peripheral edge of the flat surface on the flat region; a pressure generating protrusion provided on the bottom of the pump chamber to generate pressure based on rotation of the impeller, the pressure generating protrusion being shaped so as to axially protrude from the bottom of the pump chamber, the pressure generating protrusion being formed into a shape of a rib which extends radially so that one of two ends thereof is located between the suction and discharge ports and so that the other end thereof is located at a center of rotation of the impeller and which has a sectorial flat surface with a maximum circumferential width at said one end of the pressure generating protrusion and a minimum circumferential width at said other end of the pressure generating protrusion, whereupon the pressure generating protrusion is provided with a front side rising surface confronting a rotational direction of the impeller and a rear side rising surface opposed to the front rising surface, the front side rising surface being formed into a shape inclined in the rotational direction of the impeller; and a motor, which drives the impeller, installed in the case and having a stator and a rotor to which the impeller is attached for rotating together.