Fan and air-conditioning apparatus equipped with fan

Patent metadata

Field	Value
Publication number	US-2018355884-A1
Application number	US-201615579803-A
Country	US
Kind code	A1
Filing date	May 10, 2016
Priority date	Aug 10, 2015
Publication date	Dec 13, 2018
Grant date	—

Abstract

A fan includes an impeller including a boss serving as a center of rotation and a plurality of blades provided on an outer circumferential surface of the boss, and a structure member installed on an upstream side of the impeller in an airflow direction. The plurality of blades each have a plurality of recesses disposed only on a side of a suction surface of a leading edge. The plurality of recesses each have a rectangular shape having two longitudinal sides. Consequently, it is possible to reduce fluctuations of lift on the plurality of blades and thereby reduce discrete frequency noise.

First claim

1 . A fan comprising:
an impeller including a boss serving as a center of rotation and a plurality of blades provided on an outer circumferential surface of the boss; and a structure member installed on an upstream side of the impeller in an airflow direction, the plurality of blades each having a plurality of recesses disposed only on a side of a suction surface of a leading edge, the plurality of recesses each having a rectangular shape having two longitudinal sides.

2 . The fan of claim 1 , wherein the plurality of recesses each are longitudinal in a direction perpendicular to the leading edge.

3 . The fan of claim 1 , wherein the two sides of each of the plurality of recesses each extend along a normal to a line connecting the center of rotation and the leading edge.

4 . The fan of claim 1 , wherein the plurality of recesses are each disposed at a position where a wake flow interferes with the leading edge of each of the plurality of blades, the wake flow being a flow of air created behind the structure member.

5 . The fan of claim 1 , wherein, when the plurality of blades are viewed in a direction of a rotating axis, one of the plurality of recesses is disposed at a position where the one of the plurality of recesses is overlapped by the structure member over at least a quarter of an entire circumference during one rotation of the plurality of blades.

6 . The fan of claim 1 , wherein one of the plurality of recesses on an outer circumferential side of the plurality of blades is narrower in width than one of the plurality of recesses on an inner circumferential side.

7 . The fan of claim 1 , wherein one of the plurality of recesses on an outer circumferential side of the plurality of blades is shallower than one of the plurality of recesses on an inner circumferential side.

8 . The fan of claim 1 , wherein, on each of the plurality of blades, the plurality of recesses are disposed at smaller spacing on an outer circumferential side of the plurality of blades than on an inner circumferential side.

9 . The fan of claim 1 , wherein the plurality of blades each include a convex portion having a substantial arc shape and provided on the suction surface of the leading edge.

10 . The fan of claim 9 , wherein the convex portions vary in height in a radial direction of the impeller.

11 . An air-conditioning apparatus equipped with the fan of claim 1 .

12 . The fan of claim 1 , wherein
the plurality of recesses are provided only on the side of the suction surface of the leading edge of each of the plurality of blades and closer to an outer circumference of each of the plurality of blades than the boss, the plurality of recesses each have the rectangular shape having the two longitudinal sides and are aligned at intervals, a portion in which one of the plurality of recesses is formed and a portion in which one of the plurality of recesses is not formed are arranged alternately, spacing between adjacent ones of the plurality of recesses is 0.5 to 3.0 times spacing between the two longitudinal sides of each of the plurality of recesses.

13 . The fan of claim 1 , wherein the plurality of recesses are each disposed at a position where a wake flow interferes with the leading edge of each of the plurality of blades, the wake flow being a flow of air created behind the structure member, a distance from the structure member to one of the plurality of blades at the position is being about 1/20 or less of a diameter of each of the plurality of blades.

Assignees

• Mitsubishi Electric Corp

Inventors

• Sakoda Kenichi
• Fukui Tomoya
• Oishi Masayuki

Classifications

• F04D29/681

  especially adapted for elastic fluid pumps · CPC title

• F04D29/325

  for axial flow fans (blade mountings F04D29/34, blades F04D29/38) · CPC title

• F05D2240/303

  related to the leading edge of a rotor blade · CPC title

• F05D2250/12

  rectangular · CPC title

• F04D29/663

  Sound attenuation · CPC title