Propeller fan, fluid feeder, electric fan, and molding die

Patent metadata

Field	Value
Publication number	US-9726190-B2
Application number	US-201314391412-A
Country	US
Kind code	B2
Filing date	Apr 9, 2013
Priority date	Apr 10, 2012
Publication date	Aug 8, 2017
Grant date	Aug 8, 2017

Abstract

A propeller fan includes a boss hub portion and a blade including a front edge portion, a rear edge portion, and an outer edge portion. The outer edge portion has a front outer edge portion, a rear outer edge portion, and a connection portion connecting the front outer edge portion and the rear outer edge portion to each other. In a plan view of the blade along a central axis, a maximum radius R1 max of the outer edge portion in a portion corresponding to the front outer edge portion and a maximum radius R2 max of the outer edge portion in a portion corresponding to the rear outer edge portion satisfy a condition of R1 max >R2 max . With such a construction, a propeller fan which generates wind less in pressure fluctuation and is capable of sending comfortable wind and achieving lowering in noise is provided.

First claim

The invention claimed is:

1. A propeller fan, comprising:
a rotation shaft portion rotatable around a virtual central axis; and
a blade extending from said rotation shaft portion outward in a direction of radius of said central axis, wherein
said blade includes:
a front edge portion arranged on a leading side in a direction of rotation when the propeller fan operates,
a rear edge portion arranged on an opposite side in the direction of rotation,
an outer edge portion extending in a circumferential direction around said central axis and connecting said front edge portion and said rear edge portion to each other,
a blade root portion arranged between said blade and an outer surface of said rotation shaft portion,
a blade tip end portion arranged on an outer side in the direction of radius of said central axis, in said front edge portion,
a blade rear end portion arranged on the outer side in the direction of radius of said central axis, in said rear edge portion, and
a blade surface formed in a region surrounded by said blade root portion, said front edge portion, said blade tip end portion, said outer edge portion, said blade rear end portion, and said rear edge portion,

said outer edge portion connects said blade tip end portion and said blade rear end portion to each other,
said blade surface includes:
an inner region including said blade root portion and located on an inner side in the direction of radius of said central axis,
an outer region including said blade rear end portion and located on said outer side in the direction of radius of said central axis, and
a coupling portion extending from a front end portion to a rear end portion and coupling said inner region and said outer region to each other such that a side of a positive pressure surface of said blade surface is projecting and a side of a negative pressure surface of said blade surface is recessed,

said front end portion is located closer to said front edge portion, said blade tip end portion, or said outer edge portion than said rear edge portion,
said rear end portion is located closer to said rear edge portion than said front edge portion,
said blade surface is formed such that a stagger angle in a portion on the inner side in said direction of radius relative to said coupling portion in said blade surface is smaller than a stagger angle in a portion on the outer side in the direction of radius of said central axis relative to said coupling portion in said blade surface, and
said front edge portion has a constant height in an axial direction of said central axis between said rotation shaft portion and a position distant from said rotation shaft portion outward in the direction of radius of said central axis.

2. The propeller fan according to claim 1 , wherein
said rear edge portion has a constant height in the axial direction of said central axis on an outer circumferential side around said central axis.

3. The propeller fan according to claim 1 , wherein
said coupling portion is formed along a flow of a blade tip end vortex generated over said blade surface with rotation of said blade.

4. The propeller fan according to claim 1 , wherein
said coupling portion is formed such that an interior angle formed on the side of said negative pressure surface of said coupling portion is smallest at a center of said coupling portion in a direction of rotation of said blade, and
said blade surface located at each of said front end portion and said rear end portion is formed at 180° in a cross-sectional view along said direction of radius, which passes through each of said front end portion and said rear end portion.

5. The propeller fan according to claim 1 , wherein
when a virtual concentric circle passing through a central position in said coupling portion in a direction of rotation of said blade and centered around said central axis is drawn, said front end portion of said coupling portion is located on an outer side in a direction of radius of said concentric circle and said rear end portion of said coupling portion is located on an inner side in the direction of radius of said concentric circle.

6. The propeller fan according to claim 1 , wherein
said blade surface is formed such that, in the portion on the inner side in the direction of radius relative to said coupling portion in said blade surface, a first stagger angle defined by a virtual line of an inner region of said blade surface and said central axis is smaller than a second stagger angle defined by a virtual line of an outer region of said blade surface and said central axis.

7. The propeller fan according to claim 1 , wherein
said blade surface is formed such that an area of the blade in a portion on the inner side in the direction of radius relative to said coupling portion in said blade surface is equal to or greater than an area of the blade in a portion on the outer side in the direction of radius relative to said coupling portion in said blade surface.

8. The propeller fan according to claim 1 , wherein
a stagger angle in said blade root portion is smaller than a stagger angle in said outer edge portion,
said blade root portion of said blade surface has a warped shape such that the side of the positive pressure surface of said blade surface is projecting and the side of the negative pressure surface of said blade surface is recessed, and
said blade is formed such that a direction of warpage of said blade root portion and a direction of warpage of said outer edge portion are opposite to each other.

9. The propeller fan according to claim 1 , wherein
said coupling portion is provided as being curved from said inner region toward said outer region.

10. The propeller fan according to claim 1 , wherein
said coupling portion is provided as being bent from said inner region toward said outer region.

11. The propeller fan according to claim 1 , wherein
said outer edge portion includes a front outer edge portion located on a side of said front edge portion, a rear outer edge portion located on a side of said rear edge portion, and a connection portion connecting said front outer edge portion and said rear outer edge portion to each other.

12. The propeller fan according to claim 1 , wherein
said rear edge portion has a constant height in the axial direction of said central axis on an outer circumferential side around said central axis.

13. The propeller fan according to claim 12 , wherein
said coupling portion is formed along a flow of a blade tip end vortex generated over said blade surface with rotation of said blade.

14. The propeller fan according to claim 12 , wherein
said coupling portion is formed such that an interior angle formed on the side of said negative pressure surface of said coupling portion is smallest around a center of said coupling portion in a direction of rotation of said blade, and
said blade surface located around each of said front end portion and said rear end portion is formed at 180° in a cross-sectional view along said direction of radius, which passes through each of said front end portion and said rear end portion.

15. The propeller fan according to claim 12 , wherein
when a virtual concentric circle passing through a central position in said coupling portion in a direction of rotation of said blade and centered around said central axis is drawn, said front end portion of said coupling portion is located on an outer side in a direction of radius of said concentric circle and said rear end portion of said coupling portion is located on an inner side in the direction of radius of said concentric circle.

Assignees

• Sharp Kk

Inventors

• KUMON Yui
• Ohtsuka Masaki

Classifications

• F04D25/08 Primary

  the working fluid being air, e.g. for ventilation · CPC title

• F04D29/325 Primary

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

• F04D29/384 Primary

  characterised by form · CPC title

• F05D2240/307

  related to the tip of a rotor blade · CPC title

• F04D29/053

  Shafts · CPC title