| 摘要 |
PROBLEM TO BE SOLVED: To keep and improve the strength and to reduce the noise by solving the problems of a multi-blade fan wherein there is the fear of causing vibration in the course of operation to generate noise since the area of a blade is small and the fixing strength is poor, and an air vortex is generated to produce large high-frequency noise since the blade is short in the radial direction and provided with an inducer while a main plate is not provided with a diaphragm. SOLUTION: An impeller 1 includes the main plate 3 having a bowl-like inclined part 2 in the center, and an inducer 5 mounted on the inside diameter side of two or more blades 4, wherein the sucked air flows in the radial direction along the bowl-like inclined part 2, and the inducer 5 has a curvature of bending in the rotating direction not to collide with an air vortex at the suction port at that time, so that the air is sucked without loss, and a larger pressure rising is achieved than that without the inducer in the same rotation to reduce noise at high efficiency. Since the radial length of the blade 4 is increased for the length of the inducer 5, the strength is increased to more ensure safety. COPYRIGHT: (C)2005,JPO&NCIPI
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