| 摘要 |
PROBLEM TO BE SOLVED: To reduce sliding resistance of an impeller and improve efficiency of a fuel pump. SOLUTION: The fuel pump has a casing and an impeller. A recess group is constituted of recesses which are mutually separated by partitions and are circumferentially and repeatedly formed near an outer periphery on both of surface and back surface of the impeller. The casing has a suction port, a discharge port, a first groove opposed to the recess group of the surface of the impeller and circumferentially extending to the discharge port, and a second groove opposed to the recess group of the back surface of the impeller and circumferentially extending from the suction port. The recesses are opened from a recess inner end inside in a radial direction to a recess outer end outside in the radial direction, the first groove is opened from a first groove inner end inside in the radial direction to a first groove outer end outside the radial direction, and the second groove is opened from a second groove inner end inside in the radial direction to a second grove outer end outside the radial direction. The first groove inner end and/or the second groove inner end, or the first groove outer end and/or the second groove outer end are/is offset in the radial direction from the corresponding recess end. COPYRIGHT: (C)2005,JPO&NCIPI
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