Abstract: An axial-flow fan includes a fan motor provided with a projecting rotary shaft, and a fan having a bowl-like shaped boss part to be fitted over an end part on a rotary shaft side of the fan motor via a space and having many fan blades projected in a radial pattern on an outer periphery of the boss part, in which a plurality of air holes are formed in a shaft line direction of the rotary shaft, adjacently to the rotary shaft and intensively in a central portion of the boss part; a blade air current is generated in one direction of the shaft line by the many fan blades; and a central portion air current is formed by discharging air passing through an inside of the space in the other direction of the shaft line through the air hole. Then, the rotary shaft is cooled with the central portion air current.

Abstract: An axial-flow fan includes a fan motor provided with a projecting rotary shaft, and a fan having a bowl-like shaped boss part to be fitted over an end part on a rotary shaft side of the fan motor via a space and having many fan blades projected in a radial pattern on an outer periphery of the boss part, in which a plurality of air holes are formed in a shaft line direction of the rotary shaft, adjacently to the rotary shaft and intensively in a central portion of the boss part, a blade air current is generated in one direction of the shaft line by the many fan blades; and a central portion air current is formed by discharging air passing through an inside of the space in the other direction of the shaft line through the air hole. Then, the rotary shaft is cooled with the central portion air current.