| 摘要 |
<p>[PROBLEMS] To provide a drag use type windmill efficiently rotating even if wind is weak and developing small wind noise at the rear of the blades thereof. [MEANS FOR SOLVING PROBLEMS] The blades (3) of the drag use savonius type windmill are formed of aluminum alloy thin-sheets, and a large number of spherical embosses (6) are formed on the blades (3) by a press so as to be recessed on the front side thereof receiving wind and protruded on the rear side thereof to increase the drag of the blades (3) receiving the wind by the recessed shapes of the embosses (6) on the front side so that the blades can be efficiently rotated even if the wind is weak and that the wind noise on the rear side of the blades (3) can be reduced by the recesses and protrusions formed between the protruded shapes of the embosses (6) on the rear side and the other portions.</p> |
