| 摘要 |
PROBLEM TO BE SOLVED: To provide a thin-thickness centrifugal fan with comparatively small noise during operation.SOLUTION: A centrifugal fan 1 comprises: a motor 60; an impeller 30; and a lower casing 21 positioned below the impeller 30. The centrifugal fan 1 discharges air introduced from an inlet 33 with the rotation of the impeller 30, outward from the periphery of the impeller 30. Between the lower casing 21 and the impeller 30, a circuit board 76 is disposed. The impeller 30 includes a plurality of blades 51 disposed between a main plate 42 and an annular shroud 31, and an edge part 51a on the rotary shaft side of each blade 51 is inclined to be near an outer peripheral edge of the impeller 30 as it becomes near on the main plate 42 side from the annular shroud 31. On the surface of the main plate 42 on the lower casing 21 side, a concavity 45 annularly formed about the axis of rotation is provided, and a part of electronic components 77 mounted on the circuit board 76 enters a part of the concavity 45.SELECTED DRAWING: Figure 2 |
