| 摘要 |
PROBLEM TO BE SOLVED: To suppress disturbance of air flow in the vicinity of a suction port of an impeller by constituting at least one of a locking means fixing a rear face shroud to a rotary shaft or the rotary shaft so as to project to an opposite side of an electric motor of the suction port. SOLUTION: A rear face shroud 31 is held on a rotary shaft 37 of an electric motor by a first spacer 38, a washer 39, a pressing plate 40 and a second spacer 41 and a locking means 42 such as a nut is tightened and fixed on a screw part 43 provided at a tip part of the rotary shaft 37. A tip part 42a on an opposite side to an electric motor of the locking means 42 is projected to the opposite side to the electric motor of an opening location of a suction port 32a. Air flow flows from wide space into a suction port of a casing 48 and narrow space of the suction port 32a of an impeller 30 by an operation of the electric motor, but because the locking means 42 within the suction port 32a is projected from the suction port 32a of the impeller 30, air flow is straightened up to some degrees at a point of time when air flow passes the suction port 32a, disturbance of air flow is suppressed and a rise in pressure and inside flow are smoothly performed.
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