# US 2021/0340992 A1 · Blade and axial flow impeller using same

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- Number: US 2021/0340992 A1
- Document ID: US20210340992A1
- Status: Published application
- Kind: A1
- Application number: 17/280,111
- Filed: 2019-09-24
- Published: 2021-11-04
- Earliest claimed: 2018-09-25
- Assignees: Johnson Controls Tyco IP Holdings LLP; York Guangzhou Air Conditioning and Refrigeration Co., Ltd.
- Applicants: York Guangzhou Air Conditioning and Refrigeration CO., LTD.; Johnson Controls Technology Company
- Inventors: Bin Yuan; Li Wang; Chenggang Wu; Jian Zhu
- Web page: https://patentgrep.com/patent/US20210340992A1

## CPC

- F04D 29/384: {characterised by form}
- F04D 19/002: {Axial flow fans}
- F04D 29/666: {by means of rotor construction or layout, e.g. unequal distribution of blades or vanes}
- F04D 29/681: {especially adapted for elastic fluid pumps}
- F05D 2240/303: related to the leading edge of a rotor blade
- F05D 2240/304: related to the trailing edge of a rotor blade
- F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02)
- F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS

## Abstract

The present application discloses a blade, comprising a blade tip, a blade root, a leading edge, and a trailing edge, wherein the leading edge and the trailing edge each extend from the blade tip to the blade root; the blade may rotate around a rotation axis, and the rotation axis and a normal plane of the rotation axis perpendicularly intersect at the foot of the perpendicular; a projection of the leading edge on the normal plane along the rotation axis is a first curve, and the first curve has an even number of inflection points. The blade of the present application can reduce noise and improve aerodynamic performance when the blade rotates.

## Claims

### Claim 1

A blade (112), comprising:
a blade tip (216), a blade root (218), a leading edge (222), and a trailing edge (220), wherein the leading edge (222) and the trailing edge (220) each extend from the blade tip (216) to the blade root (218); the blade (112) may rotate around a rotation axis (X), and the rotation axis (X) and a normal plane of the rotation axis (X) perpendicularly intersect at the foot of the perpendicular (O),
characterized in that:
a projection of the leading edge (222) on the normal plane along the rotation axis (X) is a first curve, and the first curve has an even number of inflection points.

### Claim 2 (depends on 1)

The blade (112) as claimed in claim 1, characterized in that:
the number of the inflection points is 2, 4 or 6.

### Claim 3 (depends on 1)

The blade (112) as claimed in claim 1, characterized in that:
the number of the inflection points is selected such that formation of vortices is reduced.

### Claim 4 (depends on 3)

The blade (112) as claimed in claim 3, characterized in that:
the line connecting any point on the first curve and the foot of the perpendicular (O) is a first line;
the line connecting a projection point (A) of the intersection of the blade root (218) and the leading edge (222) on the normal plane along the rotation axis (X) and the foot of the perpendicular (O) is a second line;
an included angle between the first line and the second line is called a wrap angle θ; and
the wrap angle θ of any point on the first curve satisfies θ∈[0°, 40°].

### Claim 5 (depends on 1)

The blade (112) as claimed in claim 1, characterized in that:
the trailing edge (220) is provided with a plurality of grooves (232).

### Claim 6 (depends on 5)

The blade (112) as claimed in claim 5, characterized in that:
a projection of the trailing edge (220) on the normal plane along the rotation axis (X) is a second curve, wherein an included angle between the groove walls of each groove is α, the groove depth is H, and the length of the second curve is L;
the included angle and the groove depth satisfy:
α∈[10°, 100°];
H=K×L, K∈[1.5%, 20%]; and
a projection point (C) of the intersection of the blade tip (216) and the trailing edge (220) on the normal plane along the rotation axis (X) is located on the groove wall.

### Claim 7 (depends on 5)

The blade (112) as claimed in claim 5, characterized in that:
the intervals between the plurality of grooves (232) are the same.

### Claim 8 (depends on 6)

The blade (112) as claimed in claim 6, characterized in that:
the opening widths of the plurality of grooves (232) are the same, and the groove depths increase by equal difference.

### Claim 9 (depends on 5)

The blade (112) as claimed in claim 5, characterized in that:
the bottom of each of the plurality of grooves (232) is arc-shaped.

### Claim 10 (depends on 1)

An axial flow impeller (100), characterized by comprising:
a hub (110), the hub (110) having a rotation axis (X), the hub (110) being able to rotate around the rotation axis (X); and
at least two blades (112) as claimed in claim 1, the at least two blades (112) being arranged on an outer circumferential face of the hub (110).

### Claim 11

A blade (112), comprising:
a blade tip (216), a blade root (218), a leading edge (222), and a trailing edge (220), wherein the leading edge (222) and the trailing edge (220) each extend from the blade tip (216) to the blade root (218),
characterized in that:
the trailing edge (220) of the blade (112) is provided with a plurality of grooves (232).

### Claim 12 (depends on 11)

The blade (112) as claimed in claim 11, characterized in that:
the blade (112) may rotate around a rotation axis (X), and the rotation axis (X) and a normal plane of the rotation axis (X) perpendicularly intersect at the foot of the perpendicular (O);
a projection of the trailing edge (220) on the normal plane along the rotation axis (X) is a second curve, wherein an included angle between the groove walls of each groove is α, the groove depth is H, and the length of the second curve is L;
the included angle and the groove depth satisfy:
α∈[10°, 100];
H=K×L, K∈[1.5%, 20%]; and
a projection point (C) of the intersection of the blade tip (216) and the trailing edge (220) on the normal plane along the rotation axis (X) is located on the groove wall.

### Claim 13 (depends on 11)

The blade (112) as claimed in claim 11, characterized in that:
the intervals between the plurality of grooves (232) are the same.

### Claim 14 (depends on 12)

The blade (112) as claimed in claim 12, characterized in that:
the opening widths of the plurality of grooves (232) are the same, and the groove depths increase by equal difference.

### Claim 15 (depends on 11)

The blade (112) as claimed in claim 11, characterized in that:
the bottom of each of the plurality of grooves (232) is arc-shaped.

### Claim 16 (depends on 11)

An axial flow impeller (100), characterized in that the axial flow impeller (100) comprises:
a hub (110), the hub (110) having a rotation axis (X), the hub (110) being able to rotate around the rotation axis (X); and
at least two blades (112) as claimed in claim 11, the at least two blades (112) being arranged on an outer circumferential face of the hub (110).