Patent ID: 8499412
Filing Date: 2013-08-06
Classification: A47L,F01D,F04D,F05D

Abstract:
1. An electric blower comprising a stator, a rotor rotatably supported inside the stator and rotating on a rotary shaft, a bracket supporting the stator, a rotary fan attached to the rotary shaft, an air guide disposed between the bracket and the rotary fan, and a fan case with an air inlet at its center and covering the air guide and the rotary fan; the air guide comprising: a partition plate disposed between the bracket and the rotary fan; a diffuser disposed on an outer periphery of the rotary fan and including a plurality of diffuser vanes; a partition slope making contact with a bottom face of the diffuser and tilted; and a guide vane formed on a rear face of the diffuser via the partition plate; wherein the diffuser vanes form closed passages, and passage lengths of the closed passages are set to a first passage length and a second passage length that is different from the first passage length, and further wherein |L1−L2|=(λ/2) (2×m−1) (m is integer) is established, where v is a flow rate at a passage outlet, n is a number of revolutions of the rotary fan, z is a number of impellers of the rotary fan, λ is a wavelength of sound at the passage outlet, where λ=v/(n×z) is established, L1 is the first passage length, and L2 is the second passage length.