Patent ID: 9051938
Filing Date: 2015-06-09
Classification: F04D,F16C

Abstract:
1. A fan comprising: a motor; and an impeller including a plurality of blades, and arranged to rotate about a central axis through the motor to produce air currents; wherein the motor includes: the stationary portion includes: the rotating portion includes: 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 a surface of the bearing portion which is axially opposed to the first annular surface; a single seal gap arranged in an annular shape and centered on the central axis is defined between the stationary and rotating portions; and 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, the first thrust portion is 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 the first 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 the first thrust dynamic pressure bearing portion is defined by the upward-facing and downward-facing thrust dynamic pressure bearing surfaces, the rotating portion further includes a second thrust portion arranged to extend radially outward from the upper portion of the shaft; the bearing portion includes a surface arranged to face upward in the axial direction; the second thrust portion includes a second annular surface arranged axially opposite the surface arranged to face upward in the axial direction; and the surface arranged to face upward in the axial direction and the second annular surface are arranged to together define a second thrust dynamic pressure bearing portion, the fan further comprises a cover portion having an opening, arranged axially above said plurality of blades, in the axial direction, a first upper edge of said plurality of blades, opposed to the cover portion, is located lower than the second annular surface.