# US 9,039,360 B2 · Centrifugal fan

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- Number: US 9,039,360 B2
- Document ID: US9039360B2
- Status: Granted
- Kind: B2
- Application number: 13/357,776
- Filed: 2012-01-25
- Published: 2012-08-02
- Granted: 2015-05-26
- Earliest claimed: 2011-01-27
- Assignees: Minebea Co., Ltd.
- Applicants: Takako Fukuda; Seiya Fujimoto; Masaki Ogushi; Yuzuru Suzuki
- Inventors: Takako Fukuda; Seiya Fujimoto; Masaki Ogushi; Yuzuru Suzuki
- Web page: https://patentgrep.com/patent/US9039360B2

## CPC

- F04D 29/162: {of a centrifugal flow wheel}
- F04D 29/083: {especially adapted for elastic fluid pumps}
- F04D 29/22: specially for centrifugal pumps
- F04D 29/4226: {Fan casings}
- F04D 29/441: {especially adapted for elastic fluid pumps}
- F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02)

## Abstract

A centrifugal fan is provided. The centrifugal fan is configured such that an impeller having a plurality of blades along a circumferential direction and disposed between a disk-shaped main plate and an annular shroud is housed in a casing configured by an upper casing and a lower casing, and that an air suctioned from a suction opening is discharged outward in a radial direction of the impeller by a centrifugal force due to a rotation of the impeller. The shroud has a curved surface formed from an outer edge portion toward a center thereof. The shroud has a plurality of protrusions which are formed on the surface of the shroud such that a gap is formed between each of the protrusion portions and the upper casing.

## Claims

### Claim 1

A centrifugal fan configured such that an impeller, having a plurality of blades along a circumferential direction and disposed between a disk-shaped main plate and an annular shroud, is housed in a casing configured by an upper casing and a lower casing, and that an air suctioned from a suction opening is discharged outward in a radial direction of the impeller by a centrifugal force due to a rotation of the impeller,
wherein the shroud has a curved surface formed from an outer edge portion toward a center thereof,
wherein the shroud has a plurality of protrusion portions thereon which are formed annularly and spirally on the curved surface of the shroud and arranged such that a gap is formed between each of the protrusion portions and the upper casing,
and wherein a lower surface of the upper casing is faced to the top end of the protrusion portions such that each of the gaps therebetween are the same.

### Claim 2

A centrifugal fan configured such that an impeller, having a plurality of blades along a circumferential direction and disposed between a disk-shaped main plate and an annular shroud, is housed in a casing configured by an upper casing and a lower casing, and that an air suctioned from a suction opening is discharged outward in a radial direction of the impeller by a centrifugal force due to a rotation of the impeller,
wherein the shroud has a curved surface formed from an outer edge portion toward a center thereof,
wherein the shroud has at least one protrusion portion formed annularly and spirally on the curved surface of the shroud and arranged such that a gap is formed between said at least one protrusion portion and the upper casing,
and wherein a lower surface of the upper casing is faced toward the top end of said at least one protrusion portion to have said gap therebetween.