| 摘要 |
A centrifugal fan includes a casing having an upper casing and a lower casing, and an impeller disposed between the upper and lower casing. The impeller includes an upper shroud having an upper portion formed with an inlet, a lower shroud, and a plurality of blades arranged along a circumference direction between the upper shroud and the lower shroud. The lower shroud is provided only on a portion at a side of a rotation axis of the impeller such that at least an outer circumferential side portion of each blade faces an upper surface of the lower casing. A surface of the lower casing, which faces the impeller, configures a portion of a wall surface which guides the fluid introduced from the inlet. Each blade has a shape which becomes thinner as increasing a distance from the upper shroud in a direction parallel to the rotation axis. |
