Abstract: An impeller of a centrifugal fan, the impeller used in the centrifugal fan having a casing and the impeller rotatably mounted in the casing. The impeller includes a hub connecting a number of blades equiangularly disposed in a circumferential direction. The hub includes an outer circular hub partially covering an outer peripheral edge of the blade, and an inner circular hub partially covering an inner peripheral edge of the blade. The hubs are concentrically formed, and an opening is provided between the inner and outer circular hubs. The inner circular hub, outer circular hub and opening are arranged to allow air to flow back across the inner circular hub and within the casing to cool a control circuit disposed within the casing.

Abstract: A centrifugal fan includes a scroll casing having an almost cylindrical shape. The casing consists of first and second casings. The first casing constitutes one base wall and a part of a side circumferential wall of a cylinder, and the second casing constitutes the other base wall and the remaining part of the side circumferential wall. An air inlet is formed on a center portion of the base wall of the first casing, and an exhaust port that is formed on the side circumferential wall. An impeller having many blades and a motor for driving the impeller are contained in the casing. A cylindrical partition that is formed on the inside of the base wall of the second casing over the entire circumference. The partition consists of a high partition formed in at least a region close to the exhaust port and a low partition formed in the other region.

Abstract: The present invention is aimed to pursue both an inhibition of a noise when operating by maintaining stiffness of a blade, and a more effective cooling for responding to an increase of heat generation of internally mounted components, with needs for a smaller and high-performance device. A hub for connecting the blades is composed of an outer circular hub partially covering an outer peripheral edge of the blade and an inner circular hub partially covering an inner peripheral edge of the blade, the hubs concentrically formed, and an opening is provided between the two inner and outer circular hubs.

Abstract: A centrifugal fan includes a scroll casing having an almost cylindrical shape. The casing consists of first and second casings. The first casing constitutes one base wall and a part of a side circumferential wall of a cylinder, and the second casing constitutes the other base wall and the remaining part of the side circumferential wall. An air inlet is formed on a center portion of the base wall of the first casing, and an exhaust port that is formed on the side circumferential wall. An impeller having many blades and a motor for driving the impeller are contained in the casing. A cylindrical partition that is formed on the inside of the base wall of the second casing over the entire circumference. The partition consists of a high partition formed in at least a region close to the exhaust port and a low partition formed in the other region.