Blower fan

A blower fan for blowing air by rotating an impeller with a motor, the blower fan comprising:

• an impeller having a through-hole along a central axis;
• a motor including a rotational shaft placed through the through-hole;
• a washer receiving the rotational shaft protruding from the through-hole;
• and a fastener mounted on the rotational shaft and pressing the impeller through the washer to mount the impeller on the rotational shaft, wherein the washer is a plate having a predetermined shape including a plurality of projections radially extending from a circumference about a receiving hole through which the rotational shaft is placed, the washer and the impeller are separated by an elastic vibration isolator, the vibration isolator has a plurality of projections radially extending from a circumference, the vibration isolator has a first recess on a top surface of the vibration isolator, the first recess having a shape that matches an outer shape of the washer such that the washer is fitted into the first recess, the impeller has a second recess on a top surface of the impeller, the second recess having a shape that matches an outer shape of the vibration isolator such that the vibration isolator is fitted into the second recess, and wherein in a state where the washer is fitted into the first recess and the vibration isolator is fitted into the second recess:
• an outer side surface of the washer facing away from the central axis faces an inner side surface of the second recess with the vibration isolator therebetween;
• and on a plane including a section plane of the washer perpendicular to the central axis, the second recess and the washer have a same shape and different sizes.