Patent ID: 7156610

Claim:
A turbine type electric fuel pump for an automobile having a casing in which a pump portion and a motor portion are installed, wherein the pump portion comprises: a fuel intake case forming a lower end portion of the casing and having a fuel intake hole formed therein; a fuel discharge case forming a pumping chamber by contacting an inner surface of the fuel intake case in the casing and having a fuel discharge hole formed therein; and an impeller installed on the pumping chamber, wherein an inlet side ring type duct connected to the fuel intake hole is formed on the inner surface of the fuel intake case to have a semicircular section structure, and an outlet side ring type duct connected to the fuel discharge hole is formed on an inner surface of the fuel discharge case that faces the fuel intake case to have a semicircular section structure, wherein the impeller comprises: a disc portion in which a shaft assembly portion is formed at the center thereof; a plurality of blades extending from an outer circumferential surface of the disc portion outwardly in a radial direction; and a ring portion connecting the blades along the outer circumferential surface of the disc portion, wherein the outer circumferential surface of the disc portion gradually protrudes outwardly in a radial direction of the impeller from both upper and lower sides thereof to a center thereof so as to form a first protruding step, and the inner circumferential surface of the ring portion gradually protrudes inwardly in a radial direction of the impeller from both upper and lower sides thereof to a center thereof so as to form a second protruding step, so that a space between the blades has a structure in which two semicircular sections, each being defined by the outer circumferential surface of the disc portion and the inner circumferential surface of the ring portion, do not overlap and are connected to each other, and wherein the first protruding step is deviated upward with respect to a center line of the impeller and the second protruding step is deviated downward with respect to the center line, whereby rotation fluid in the pump portion is smoothly moved from the fuel intake case to the fuel discharge case.