| 摘要 |
PROBLEM TO BE SOLVED: To provide a centrifugal fan for a ventilating device of extremely low resonance noise. SOLUTION: Resonance noise generated by overlap or the like of prominent frequency of natural vibration as a latent characteristic of the centrifugal fan and natural frequency of a used DC motor is suppressed by reducing area which transmits vibration of a disk like hub plate 9 which is a support member of a blade 11 in an impeller 7. As an embodiment, area of the hub plate contacting air is reduced by providing a hole 10 on the hub plate or attaching damping material 19. COPYRIGHT: (C)2005,JPO&NCIPI
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