FUEL PUMP

PROBLEM TO BE SOLVED: To provide a fuel pump preventing wear of an impeller by eliminating pressure difference of fuel applied on a surface of the impeller and improving pump efficiency. SOLUTION: This fuel pump has a small groove communicating to a pressure raising groove provided on a front face of the impeller and has a large groove communicating to the pressure raising groove formed on a back face or a recess part composed of a through hole and an intermediate part having roughly blade like cross section shape formed inside of the pressure raising groove of the impeller. Fuel passes through the groove communicating to a blade or the recess part and presses the impeller when the impeller rotates, to eliminate pressure difference of fuel applied on the front face and the back face of the impeller. Consequently, since pressure difference is eliminated, the impeller and a casing do not contact and impeller is not worn. Since position of the impeller is not shifted, clearance between the impeller and the casing can be made small. COPYRIGHT: (C)2005,JPO&NCIPI