Fan

摘要

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.

主权项

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; anda 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 LA of the first part being longer than a radial length LB of the second part, wherein the opening of the cover portion has a radial length LC larger than the radial length LA of the first part, the radial length LC 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 LF and an axial length LE, wherein the radial length LF of the blade support is larger than the axial length LE thereof, wherein a radial length LD 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 LB 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.