Blade of an air-conveying wheel with an S-shaped blade edge geometry

Patent metadata

Field	Value
Publication number	US-10612556-B2
Application number	US-201816056708-A
Country	US
Kind code	B2
Filing date	Aug 7, 2018
Priority date	Apr 25, 2016
Publication date	Apr 7, 2020
Grant date	Apr 7, 2020

Abstract

The disclosure relates to a blade edge of at least one blade of an air-conveying wheel with an axial-side blade edge contour which extends from a blade leading edge to a blade trailing edge along a curve, wherein the blade edge contour has at least one front section which adjoins the blade leading edge in the radial direction, a rear section which adjoins the blade trailing edge in the radial direction, and a central section which lies between the front section and the rear section. The blade edge contour has an S-shaped curve progression in the central section in a lateral cross-sectional view, thus increasing an axial height of the blade in the direction of the blade trailing edge.

First claim

What is claimed is:

1. A blade edge of at least one blade of an air-conveying wheel with an axial-side blade edge contour that extends from a blade leading edge to a blade trailing edge along a curve, the blade edge contour has at least one front section (I) that adjoins the blade leading edge in the radial direction, a rear section (III) that adjoins the blade trailing edge in the radial direction, and a central section (II) that lies between the front section (I) and the rear section (III), the blade edge contour has an S-shaped curve progression in the central section (II) in a lateral cross-sectional view, this increasing an axial height h of the blade in the direction of the blade trailing edge, the central section (II) has a curve progression along a chord length s of the blade from a beginning of the central section s central section min to an end of the central section s central section max , that is determined normalized by the formula

h
⁡

(
s
)

=

tanh
(

s
-

(

s

central
⁢

⁢
section

min

+

s

central
⁢

⁢
section

max

2

)

t

)

*

h
⁡

(

s

central
⁢

⁢
section

min

)

+

h
⁡

(

s

central
⁢

⁢
section

max

)

2

+

h
⁡

(

s

central
⁢

⁢
section

min

)

+

h
⁡

(

s

central
⁢

⁢
section

min

)

+

h
⁡

(

s

central
⁢

⁢
section

max

)

2

wherein h corresponds to an axial height of the blade and s to a chord length of the blade, that extends from the blade leading edge to the blade trailing edge, wherein h and s in each case have values of 0 to 1,
and t∈[0, 1],
0.1≤ s central section min ≤s central section max ,

s central section min ≤s central section max ≤0.8.

2. The blade edge according to claim 1 , wherein the S-shaped curve progression corresponds to a curve of a hyperbolic tangent.

3. The blade edge according to claim 1 , wherein the blade edge contour has a continuous curve progression in the front section (I) and in the rear section (III) at least in sections.

4. The blade edge according to claim 3 , wherein the blade edge contour has a continuous curve progression in the front section (I) and in the rear section (III) over 50-100% of the radial length thereof.

5. The blade edge according to claim 1 , wherein the front section (I) and the rear section (III) directly adjoin the central section (II).

6. The blade edge according to claim 5 , wherein the curve of the blade edge contour is, in each case, continuously differentiable on both sides at the respective adjoining points of the front section (I) and the central section (II) as well as of the rear section (III) and the central section (II).

7. The blade edge according to claim 1 , wherein the front section (I) has a curve progression along a chord length s of the blade that is determined normalized by the formula
h ( s )= a×s+d

where h corresponds to an axial height of the blade and s corresponds to a chord length of the blade, which extends from t

Assignees

• Ebm Papst Mulfingen Gmbh & Co Kg

Inventors

• Conrad Daniel
• Pfaff Christian

Classifications

• F04D29/30 Primary

  Vanes · CPC title

• F05D2240/307

  related to the tip of a rotor blade · CPC title

• F04D25/082

  the unit having provision for cooling the motor · CPC title

• H02K5/24

  specially adapted for suppression or reduction of noise or vibrations · CPC title

• F05D2200/25

  Hyperbolic trigonometric, e.g. sinh, cosh, tanh · CPC title