Blower fan

1. A blower fan comprising:

a hub;

a plurality of blades spaced apart an asymmetric distance from one another about the hub; and

a balancer connected to the hub to balance the blades,

wherein the hub comprises,

a circular main plate,

a circumferential surface surrounding a circumference of the main plate to be connected to the blades,

a hub axis disposed in the circumferential surface, one end of the hub axis connected to a central part of the main plate, and

a plurality of ribs radially disposed to be connected to the circumferential surface,

wherein the balancer has a half cylindrical shape, protrudes from an inner surface of the circumferential surface to a rotational axis (C) of the hub, and is disposed between two ribs among a plurality of ribs, the balancer being integrally molded with the hub,

wherein the balancer is disposed such that a center of mass of the blower fan is positioned at a rotational axis (C) of the hub, and

wherein the plurality of blades is disposed such that the balancer does not interfere with the plurality of ribs,

wherein the plurality of blades are disposed such that at least two adjacent included angles, among a plurality of included angles each of which is an angle between reference lines from respective centers of mass of the plurality of blades toward a rotational axis (C) of the hub, are different from each other,

wherein the balancer is disposed at a side of the hub between the plurality of blades which have the largest included angle among the plurality of included angles,

wherein the plurality of blades comprise only three blades, the three blades including a first blade having a first center of mass, a second blade having a second center of mass, and a third blade having a third center of mass,

wherein the balancer is disposed such that a sum of a plurality of centripetal force vectors generated from the center of mass of each blade to the rotational axis (C) and a plurality of centripetal force vectors generated from the center of mass of the balancer to the rotational axis (C) is zero when the blower fan is rotated,

wherein the first blade, the second blade, and the third blade are each connected to the hub and spaced apart an asymmetric distance from one another,

wherein there is a first reference line from the first center of mass to a rotational axis (C) of the hub, a second reference line from the second center of mass to the rotational axis (C) of the hub, and a third reference line from the third center of mass to the rotational axis (C) of the hub,

wherein at least two of a first included angle a 1 between the first reference line and the second reference line, a second included angle between the second reference line and the third reference line, and a third included angle between the first reference line and the third reference line are different from each other,

wherein the balancer is disposed such that a center of mass of the blower fan is positioned at the rotational axis (C) of the hub,

wherein the first included angle is 120 degrees, the second included angle is 130 degrees, and the third included angle is 110 degrees, and

wherein the balancer is disposed between the second blade and the third blade.

2. The blower fan of claim 1 , wherein the balancer is disposed between the plurality of blades which have the largest included angle among the first, second, and third included angles.

3. The blower fan of claim 1 , wherein the balancer is integrally formed with the circumferential surface.

4. The blower fan of claim 3 , wherein the ribs are connected to the hub axis.