| 摘要 |
PROBLEM TO BE SOLVED: To balance force applied to both the sides of an impeller so as to reduce the rolling frictional resistance of the impeller by forming a pump groove passage in the periphery of the impeller stored between opposed surfaces of two bodies and arranging in respective surfaces a plurality of cavities circumferentially separated/divided from each other. SOLUTION: A pump groove passage 14 is formed in the periphery of an impeller 12. The impeller 12 is stored between opposed flat surfaces 16, 18 of bodies 20, 22. Respective surfaces 16, 18 have a plurality of cavities circumferentially separated/divided from each other. When the cavities are filled with fuel, force applied to both the sides of the impeller 12 is balanced and the impeller 12 is positioned in a center between the bodies 20, 22. Thusly, the cavities are formed, thereby a frictional engagement area of the impeller 12 with the bodies 20, 22 is reduced, and the impeller 12 is positioned in the center, thereby a gap is formed between surfaces 40, 42 located adjacently to the impeller 12, thus frictional contact of the impeller 12 with the bodies 20, 22 can be reduced. |
