| 摘要 |
An axial fan which includes a hub portion having the rotational center thereof and blades arranged on the outer periphery of the hub portion is equipped with a thickness reinforcing portion which extends from the joint portion between the blade front edge portion of the blade and the hub portion to the outer periphery of the blade along the blade front edge and whose width and thickness are smaller as the distance from the rotational center of the hub portion is larger. Furthermore, the axial fan is equipped with an additional blade. There is achieved an arc corresponding to the overlap portion between the blade and a circle of a first radius which passes from the blade front edge side of the blade to the blade rear edge side and has as the center thereof any reference point displaced from the rotational center on a plane vertical to the rotational axis of the hub portion and the blade. The arc is set as a blade shape changing portion from which the shape of the blade is changed, and the additional blade is designed so as to project from the blade shape changing start portion to the blade negative pressure plane side.
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