To facilitate the positioning at the time of screwing an impeller to a shaft of a driving unit, and to improve the assembling workability by providing one or more holes or recessed parts in a disc-shaped impeller having a blade, which is formed of multiple sector grooves extended in the radial direction in the periphery, at a part inside of the blade part.
A motor 1 as a driving unit of an electric air pump is surrounded by a motor cover 9, and fixed to an inner casing 3 of two casings by a screw 10, and an impeller 7 is fixed to a shaft 4 by a screw 11 so as to form a pump flow passage coaxial with a casing 3. The other casing is fixed to the casing 3 so as to cover the impeller 7, the casing 3 and the pump flow passage. In this case, the impeller 7 is fixed by using an auxiliary appliance through a fixing hole 14 provided inside of a blade part 13 of the impeller 7. With this structure, the impeller 7 can be screwed to the shaft 4 without damaging the blade 13, and since the assembling of a driving unit side can be firstly performed, degree of freedom of assembling can be improved.
OTAKA YASUNORI
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