To prevent degradation in cooling efficiency caused by the adhesion of the dust or the like to a dust proof net.
A wind-causing wing 42 is provided on the outer peripheral part of a hub 41 so that the wind-causing wing can change its position around an axial center P2 set in the direction which the axial center P2 intersects a rotational axial center P1. The wind-causing wing causes wind by rotating integrally with the hub 41 around the rotational axial center P1 of the hub. The wind-causing structure is provided with an operating mechanism 77 which switches the position of the wind-causing wing 42 between a following wind causing position and a reverse wind causing position. The wind-causing structure is constituted so that the wind velocity, which is in a reverse-wind-causing state with the wind-causing wing 42 set in the reverse wind causing position, is higher than the wind velocity in a following-wind-causing state with the wind-causing wing 42 set in the following wind causing position.
OOMORI MIKIO
KAMIKITA CHIHARU
MIYANO YOSHIMI
KITANO TATSUYA
TOMINAGA TOSHIO
YOSHIDA YUSAKU
