Blower fan having impeller and motor

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

• a motor including a rotational shaft having a threaded portion at a distal end of the rotational shaft;
• an impeller having a mount hole through which the rotational shaft is placed, the mount hole being a through-hole at a rotation center;
• rubber washers sandwiching a portion of the impeller having the mount hole, the rubber washers having insertion holes through which the rotational shaft is placed;
• and
• a nut placed on the threaded portion of the rotational shaft placed through the impeller and the rubber washers to fix the impeller to the rotational shaft,
• wherein the rotational shaft includes, within a predetermined length from the distal end, a locking surface that is a flat portion of a peripheral surface of the rotational shaft to lock rotation of the impeller with respect to the rotational shaft,
• the insertion holes of the rubber washers and the mount hole of the impeller through which the rotational shaft is placed each include an arc portion positioned with respect to the peripheral surface of the rotational shaft and a linear portion positioned with respect to the locking surface of the rotational shaft, and
• a spacing portion of the linear portion of the mount hole extends in a direction away from the locking surface and reaches an inner-circumference of the mount hole, so as to form a cut out surrounded by the spacing portion of the mount hole, the inner-circumference of the mount hole, and the locking surface of the rotational shaft.