Fan with low noise, high air flow and high wind pressure

摘要

This invention relates to a fan. According to the rotational direction, the outermost point of the front side of the fan is leading to the innermost point of the front side such that the portion first contacting air is minimized and the noise of the fan is minimized. According to the rotational direction, the back of the fan blade recesses from the inner side and outer side of the fan blade to the center of the fan blade. According to the rotational direction, the frontage of the fan blade convexedly protrudes from the inner side and outer side of the fan blade to the center of the fan blade. The wake side is rounded. The diameter of the top side is smaller than that of the peripheral wall of the center portion. The invented fan improves noise, air flow and wind pressure.