Centrifugal fan having main blade with axially upper end projecting upward

摘要

A centrifugal fan may include an impeller arranged to rotate about a rotation axis, an impeller case arranged to accommodate the impeller, a motor arranged to rotate the impeller, and a motor case arranged to accommodate the motor. The impeller may include a boss portion joined to a shaft arranged to rotate about the rotation axis, a hub arranged to extend radially outward from the boss portion, and a plurality of blades. Each blade may be arranged to extend radially outward. An inner wall of the impeller case may include an inside surface extending radially outward along an upper end portion of each blade. A side end portion of an air inlet defined in a central portion of the impeller case may include a curved surface projecting radially inward.

主权项

1. A centrifugal fan comprising:
an impeller arranged to rotate about a rotation axis; an impeller case arranged to accommodate the impeller; a motor arranged to rotate the impeller; and a motor case joined to the impeller case and arranged to accommodate the motor; wherein the impeller comprises:
a boss portion joined to a shaft arranged to rotate about the rotation axis;a hub arranged to extend radially outward from an outer circumferential surface of the boss portion; anda plurality of blades arranged on an upper surface of the hub; each blade is arranged to extend radially outward away from the rotation axis; an inner wall of the impeller case is arranged to cover the blades, and comprises an inside surface extending radially outward along an upper end portion of each blade; and the impeller case comprises an air inlet defined in a central portion thereof, with a side end portion of the air inlet comprising a curved surface projecting radially inward; wherein the curved surface of the air inlet is arranged to have an axial dimension smaller than a radial dimension thereof, the radial dimension being a dimension in a radial direction from a most radially inner point of the curved surface to a point where the curved surface extends furthest away from the impeller in an axial direction; wherein the blades comprise:
a main blade arranged to extend radially outward from a point radially inward of a radially innermost end of the curved surface of the air inlet; andan auxiliary blade arranged to extend radially outward from a point radially outward of the radially innermost end of the curved surface of the air inlet; the main blade has an axially upper end projecting upward and positioned radially outward of the radially innermost end of the curved surface of the air inlet; a distance between the main blade and the inside surface of the impeller case is arranged to be shortest at the axially upper end of the main blade; and wherein a plurality of auxiliary blades is equidistantly located between the two adjacent main blades.