| 摘要 |
A ventilation fan is provided to support stress generated in joint sections by rotating a blade as the joint section in which the blade and the hub are coupled concentrates stress rearward. A ventilation fan comprises a hub(141), a plurality of blades(142), a first joint section, and a second joint section. A plurality of blades are arranged at the outer circumference of the hub. A part of trailing edge of the blades is positioned at the rear end of the hub. The joint section(144) is the side in which each blade and the hub are coupled. The joint section comprises the first joint section and the second joint section. The width of the first joint section is reduced rearward. The second joint in is extended from the first joint section. The width of the second joint decreases.
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