Fan

Patent metadata

Field	Value
Publication number	US-9341189-B2
Application number	US-201213523024-A
Country	US
Kind code	B2
Filing date	Jun 14, 2012
Priority date	Jun 30, 2011
Publication date	May 17, 2016
Grant date	May 17, 2016

Abstract

A fan includes a motor and an impeller. The motor includes a stationary portion and a rotating portion rotatably supported by the stationary portion. The stationary portion includes a stator and a bearing portion arranged inside of the stator. The rotating portion includes a rotor magnet arranged radially outside the stator; a shaft inserted in the bearing portion, and having an upper portion fixed to the impeller directly or through one or more members; and a thrust portion arranged axially opposite the bearing portion, and including an annular surface arranged around the shaft.

First claim

What is claimed is:

1. A fan comprising:
a motor comprising a stationary portion and a rotating portion rotatably supported by the stationary portion;
an impeller including a blade support and a plurality of blades, and arranged to rotate about a central axis through the motor to produce air currents, wherein the blade support comprising a blade support fixing portion and a blade support portion wherein said plurality of blades are fixed to the motor via the fixing portion and the blade support portion, the blade support portion being radially outside the fixing portion; and

a housing including a cover portion, the housing accommodating the motor and the impeller, the cover portion having an opening to expose the motor, wherein the stationary portion includes:
a stator; and
a bearing portion arranged inside of the stator, the bearing portion comprising an upper end surface;

wherein the rotating portion includes:
a rotor magnet arranged radially outside the stator;
a shaft comprising a shaft portion and a top plate portion, the shaft portion inserted in the bearing portion, the shaft portion having an upper end extending radially outward to the top plate portion, the top plate portion comprising a first annular surface at a lower surface thereof and a portion fixed to the impeller directly or through one or more members; and

wherein a radial dynamic pressure bearing portion arranged to generate a fluid dynamic pressure in a lubricating oil is defined in a radial gap defined between an inner circumferential surface of the bearing portion and an outer circumferential surface of the shaft, while a first thrust dynamic pressure bearing portion arranged to generate a fluid dynamic pressure in the lubricating oil is defined in a thrust gap defined between the first annular surface and the upper end surface;
wherein a single seal gap arranged in an annular shape and centered on the central axis is defined between the stationary and rotating portions; and
wherein the seal gap, the radial gap, and the thrust gap are arranged to together define a single continuous bladder structure, the lubricating oil is arranged continuously in the bladder structure, and a surface of the lubricating oil is defined only in the seal gap,
wherein each of the blades has a first part and a second part, the first part axially overlapped with the cover portion and the second part axially exposed to the opening, a radial length L A of the first part being longer than a radial length L B of the second part,
wherein the opening of the cover portion has a radial length L C larger than the radial length L A of the first part, the radial length L C being a length between an outer periphery of the opening and an outer periphery of the blade support fixing portion,
wherein the blade support has a radial length L F and an axial length L E , wherein the radial length L F of the blade support is larger than the axial length L E thereof,
wherein a radial length L D extending from a radially innermost end of the blade support to a radially innermost end of the second part is larger than the radial length L B of the second part, wherein the blade support portion has an upper end located at a level lower than an upper end of the first part,
wherein the upper end of the first part of each blade is arranged at a level lower than that of the first thrust dynamic pressure bearing portion.

2. The fan according to claim 1 , wherein the bearing portion includes:
a tubular sleeve; and
a bearing housing arranged to cover an outer circumferential surface of the sleeve.

3. The fan according to claim 2 , wherein the stationary portion further includes a cap member arranged to close a lower end of the bearing housing.

4. The fan according to claim 3 , wherein
the shaft further comprises a thrust plate arranged to extend radially outward from the shaft at a bottom portion of the bladder structure;
an upper surface of the thrust plate includes an upward-facing thrust dynamic pressure bearing surface defined by a second annular surface;
the bearing portion includes a downward-facing thrust dynamic pressure bearing surface arranged to face downward in an axial direction;
the upward-facing and downward-facing thrust dynamic pressure bearing surfaces are arranged axially opposite each other; and
a second thrust dynamic pressure bearing portion is defined by the upward-facing and downward-facing thrust dynamic pressure bearing surfaces.

5. The fan according to claim 4 , wherein a lower end of each of the blades is arranged at a level higher than that of the upward-facing thrust dynamic pressure bearing surface.

6. The fan according to claim 5 , wherein
a lower surface of the thrust plate includes a third annular surface; and
the third annular surface is opposed to a bottom surface of the bladder structure to define a third thrust dynamic pressure bearing portion.

7. The fan according to claim 5 , wherein
the rotating portion includes a tubular portion arranged to extend downward and centered on the central axis, and arranged radially opposite an outer circumferential surface of the bearing portion; and
the seal gap is defined between an upper portion of the outer circumferential surface of the bearing portion and an inner circumferential surface of the tubular portion, the seal gap being arranged to gradually increase in radial width with decreasing height.

8. The fan according to claim 4 , wherein
a lower surface of the thrust plate includes a third annular surface; and
the third annular surface is opposed to a bottom surface of the bladder structure to define a third thrust dynamic pressure bearing portion.

9. The fan according to claim 4 , wherein
the rotating portion includes a tubular portion arranged to extend downward and centered on the central axis, and arranged radially opposite an outer circumferential surface of the bearing portion; and
the seal gap is defined between an upper portion of the outer circumferential surface of the bearing portion and an inner circumferential surface of the tubular portion, the seal gap being arranged to gradually increase in radial width with decreasing height.

10. The fan according to claim 3 , wherein
the first thrust dynamic pressure bearing portion is arranged to extend radially outward from the upper portion of the shaft;
the bearing portion includes an upward-facing thrust dynamic pressure bearing surface arranged to face upward in an axial direction;
the first annular surface is a downward-facing thrust dynamic pressure bearing surface arranged axially opposite the upward-facing thrust dynamic pressure bearing surface; and
the thrust dynamic pressure bearing portion is defined by the upward-facing and downward-facing thrust dynamic pressure bearing surfaces.

11. The fan according to claim 10 , wherein
the rotating portion includes a tubular portion arranged to extend downward and centered on the central axis, and arranged radially opposite an outer circumferential surface of the bearing portion; and
the seal gap is defined between an upper portion of the outer circumferential surface of the bearing portion and an inner circumferential surface of the tubular portion, the seal gap being arranged to gradually increase in radial width with decreasing height.

12. The fan according to claim 3 , wherein the shaft further includes a rotor holder including the top plate portion, wherein the top plate portion is arranged substantially in a shape of a disk, wherein the top plate portion is radially overlapped with the cover portion.

13. The fan according to claim 2 , wherein
the bearing housing is defined by a single con

Assignees

• Hirono Teiichi
• Noda Shinichiro
• Ikegami Yoshiharu
• Hasegawa Tomohiro
• Yoneda Tomohiro
• Matsumoto Shunji
• Yoo Seungsin
• Kabune Kouta
• Nidec Corp

Inventors

• Hirono Teiichi
• Noda Shinichiro
• Ikegami Yoshiharu
• Hasegawa Tomohiro
• Yoneda Tomohiro
• Matsumoto Shunji
• Yoo Seungsin
• Kabune Kouta

Classifications

• F04D29/057

  hydrostatic; hydrodynamic · CPC title

• F04D29/063

  specially adapted for elastic fluid pumps · CPC title

• F04D25/0626

  Details of the lubrication · CPC title

• F04D29/083

  especially adapted for elastic fluid pumps · CPC title

• F16C17/102

  with grooves in the bearing surface to generate hydrodynamic pressure · CPC title