| 摘要 |
PROBLEM TO BE SOLVED: To reduce effectively noise at an electric blower, in particular fan sound generated between a centrifugal fan and an inlet part of a diffuser guide blade arranged at an outer peripheral side of the centrifugal fan.SOLUTION: An air guide 16 of the present invention comprises a partition plate 16b partitioning between a bracket and a centrifugal fan, a diffuser arranged at an outer peripheral side of the centrifugal fan and having a plurality of diffuser guide blades 16a, and a return vane 16c formed at a rear surface of the diffuser through the partition plate 16b. At the air guide 16, there are provided even number of the diffuser guide blades 16a and there are provided openings at prescribed positions of every other diffuser guide blades 16a. When N[r/min] is the number of revolutions of an electric blower, Z is the number of blades at the centrifugal fan, and V[m/sec] is an acoustic velocity, the air guide 16 is arranged at the prescribed position from the diffuser guide blades 16a and the expression of D=V/[(N/60)×Z×2]/n [where n=1,2, ...] is satisfied.SELECTED DRAWING: Figure 3 |
