Patent ID: 7114921

Claim:
A fan comprising: a boss portion having a cylindrical shape; a plurality of blades extending from an outer periphery of the boss portion in a radial direction; and a ring member integrated with radial outside edges of the blades, wherein the ring member has an axial dimension smaller than an axial dimension of the blade with respect to an axial direction of the boss portion, the ring member includes a body portion extending in the axial direction of the boss portion and an extending portion extending in a form of bell from an upstream end of the body portion of the ring member toward an upstream position of the blades with respect to an air flow, and the extending portion is disposed such that a downstream end of the extending portion connects to the upstream end of the body portion to form a first base point, the first base point is arranged in a range that begins at a point 25% of a distance from an upstream end of the radial outside edge of the blade and ends at a point 85% of the distance from the upstream end of the radial outside edge of the blade, with respect to the axial dimension of the blade; the fan further comprising: a connecting wall extending in the axial direction and connecting the body portion of the ring member to at least one of an upstream portion and a downstream portion of the radial outside edge of the blade, the upstream portion and the downstream portion protruding from the body portion of the ring member in the axial direction.