# US 7,070,392 B2 · Impeller blade

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- Number: US 7,070,392 B2
- Document ID: US7070392B2
- Status: Granted
- Kind: B2
- Application number: 10/620,579
- Filed: 2003-07-15
- Published: 2004-03-18
- Granted: 2006-07-04
- Earliest claimed: 1998-07-20
- Assignees: Minebea Co., Ltd.
- Inventors: Phillip James Bradbury; Phep Xuan Nguyen; Chalmers R. Jenkins, Jr.
- Web page: https://patentgrep.com/patent/US7070392B2

## CPC

- F04D 29/384: {characterised by form}
- H02K 11/33: Drive circuits, e.g. power electronics (H02K11/38 takes precedence)
- H02K 7/14: Structural association with mechanical loads, e.g. with hand-held machine tools or fans (with fan or impeller for cooling the machine H02K9/06)
- H02K 29/00: Motors or generators having non-mechanical commutating devices, e.g. discharge tubes or semiconductor devices
- Y10S 416/02: Formulas of curves
- Y10S 416/05: Variable camber or chord length
- F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02)
- H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53})
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

Impeller blades and a method for designing impeller blades wherein the blades comprise a plurality of specially designed airfoil sections, each section having along substantially the entire length thereof, a cross-sectional shape characterized by a maximum thickness located substantially constantly between about 16% chord to about 23% chord and a maximum camber located substantially constantly between about 40% chord to about 51% chord. The blades are designed so that the axial width of the blades is decreased while maintaining performance parameters and design constraints.

## Claims

### Claim 1

A blade for an impeller of an axial fan having a root portion, a tip portion, a leading edge, a trailing edge, said blade having:
a cross-sectional shape, taken anywhere along a radius of said blade, characterized by a maximum thickness located substantially constantly as a percentage of chord and a maximum camber located substantially constantly as a percentage of chord; and
a stagger angle that increases from said root portion to said tip portion.

### Claim 2

A blade for an impeller of an axial fan having a root portion, a tip portion, a leading edge, a trailing edge, said blade having:
a cross-sectional shape, taken anywhere along a radius of said blade, characterized by a maximum thickness located substantially constantly between about 16% chord to about 23% chord and a maximum camber located substantially between about 40% chord to about 51% chord.

### Claim 3

A blade for an impeller of an axial fan having a root portion, a tip portion, a leading edge, a trailing edge, said blade being characterized:
in plan form wherein the blade is varied from said root portion to said tip portion with a maximum chord located between said root portion and said tip portion, said leading edge and said trailing edge of said blade are convex from said root portion to said tip portion; and
a cross-sectional shape, taken anywhere along a radius of said blade, characterized by a maximum thickness located substantially constantly as a percentage of chord; and
a stagger angle that increases from said root portion to said tip portion.

### Claim 4

A blade for an impeller of an axial fan having a root portion, a tip portion, a leading edge, a trailing edge, said blade being characterized:
in plan form wherein the blade is varied from said root portion to said tip portion with a maximum chord located between said root portion and said tip portion, said leading edge and said trailing edge of said blade are convex from said root portion to said tip portion; and
a cross-sectional shape, taken anywhere along a radius of said blade, characterized by a maximum camber located substantially constantly as a percentage of chord; and
a stagger angle that increases from said root portion to said tip portion.

### Claim 5 (depends on 3)

The blade of claim 3 where said maximum thickness is located substantially constantly between about 16% chord to about 23% chord.

### Claim 6 (depends on 4)

The blade of claim 4 where said maximum camber is located substantially constantly between about 40% chord to about 51% chord.

### Claim 7

A blade for an impeller of an axial fan having a root portion, a tip portion, a leading edge, a trailing edge, said blade being characterized:
in plan form wherein the blade is varied from said root portion to said tip portion with a maximum chord located between said root portion and said tip portion, said leading edge and said trailing edge of said blade are convex from said root portion to said tip portion; and
a cross-sectional shape, taken anywhere along a radius of said blade, characterized by said leading edge being similar to a parabola in shape, convex upper surface, and a lower surface which is convex towards said leading edge and concave towards said trailing edge; and
a stagger angle that increases from said root portion to said tip portion.

### Claim 8

A blade for an impeller of an axial fan having a root portion, a tip portion, a leading edge, a trailing edge, said blade having:
a cross-sectional shape, taken anywhere, along a radius of said blade, characterized by a maximum thickness located substantially constantly as a percentage of chord, said leading edge being similar to a parabola in shape, a convex surface, and a lower surface which is convex towards said leading edge and concave towards said trailing edge; and
a stagger angle that increases from said root portion to said tip portion.