Patent ID: 8764418
Filing Date: 2014-07-01
Classification: F04D

Abstract:
1. A centrifugal fan comprising: an electric motor including a rotary shaft; an impeller fixed to the rotary shaft of the electric motor to rotate; and a casing including a suction port opening in an axial direction of the rotary shaft, the casing being constituted from a first wall portion with the suction port formed therein, a second wall portion facing the first wall portion with the impeller interposed therebetween, and a third wall portion coupling the first wall portion and the second wall portion, wherein: the impeller includes: the annular blade mounting member is located between the first wall portion and the second wall portion and radially outside the bottom wall; the one end of each stem is fixed to a circumferential wall portion of the circumferential wall in the vicinity of the suction port; each of the stems is shaped to assist the impeller to suck air in the axial direction through the suction port during rotation of the impeller in a normal rotation direction; each of the stems has a curved section, as cut in a direction orthogonal to a longitudinal direction of the stem, which is curved to be convex in a direction opposite to the normal rotation direction of the impeller; each of the stems includes a first end edge portion located on a side of the suction port and a second end edge portion located on a side opposite to the suction port; the first end edge portion is shifted more than the second end edge portion in the normal rotation direction of the impeller; the other end of each stem is terminated in the radial direction outside an opening edge portion of the suction port; the annular blade mounting member is located in the radial direction outside the opening edge portion of the suction port; the annular blade mounting member is located in the radial direction outside the opening edge portion and includes a first side surface facing the first wall portion and a second side surface facing the first side surface in the axial direction; the first side surface of the annular blade mounting member is curved such that a distance between the first side surface and the first wall portion increases outwardly in the radial direction, and the curved surface is convex toward the second wall portion; the second side surface is curved to extend in parallel with the first side surface; the one end of each blade is fixed to the second side surface; and the blades include a plurality of first blades and a plurality of second blades;