Cooling fan for rotating machine
A cooling fan for rotating machine having a sufficient cooling performance, mass production performance and easiness in mounting is provided. A centrifugal fan mounted to a rotating shaft 21 of rotating machine for introducing a cooling air to the rotating machine, is provided with a hub 12 mounted at the rotating shaft, a main plate 11 formed in ring shape and disposed concentrically at the hub, a side plate 14 in ring shape having the outer circumference smaller than the inner circumference of the main plate and formed integrally with the hub so that it is disposed with an interval to the main plate in the axial direction of the rotating shaft, and a plurality of impeller blades 13 implanted on the hub and disposed along the axial direction of the rotating shaft and regularly in the radial direction so as to connect the main plate to the hub to form a space between the main plate, the side plate and the hub, some impeller blades 13 a of said impeller blades being constituted to reach the outermost circumference portion in the radial direction, while the others 13 b reaching only the middle, wherein the main plate and the side plate are formed so that they are not overlapped with each other when seen from the axial direction of the rotating shaft.
1. A centrifugal fan mounted on a rotating shaft of a rotating machine for introducing cooling air to said rotating machine, said centrifugal fan comprising:
a hub mounted about said rotating shaft;
a main plate formed in a ring shape and disposed concentrically at said hub;
a side plate in a ring shape having an outer circumference smaller than an inner circumference of said main plate and formed integrally with said hub so that said side plate is disposed with an interval to said main plate in an axial direction of said rotating shaft; and
a plurality of flat impeller blades implanted on said hub, and disposed along the axial direction of said rotating shaft, and regularly spaced in a radial direction so as to connect said main plate to said hub to form a space between said main plate, said side plate and said hub, some of said impeller blades reaching an outermost circumference portion in said radial direction, while others of the impeller blades reaching only a middle portion in said radial direction,
said main plate and said side plate being formed so that said main plate and said side plate avoid overlapping with each other when seen from the axial direction of the rotating shaft, and the others of said impeller blades being gouged at portions outward in the radial direction and forming spaces on both sides of the some impeller blades.
2. The centrifugal fan according to claim 1 , wherein at least one of two side edge portions of said impeller blades are inclined toward the axial direction of said rotating shaft.
3. The centrifugal fan according to claim 1 , wherein at least one of said main plate and said side plate is inclined toward the radial direction so that a ventilation resistance along the axial direction of said rotating shaft is reduced.
4. The centrifugal fan according to claim 1 , wherein said side plate has a curved surface for guiding a cooling air flowing in the axial direction of said rotating shaft outward in said radial direction.