Blower fan

Abstract

A blower fan includes an impeller cup; a shaft including an end arranged to project axially upward from the impeller cup; a rotor magnet fixed to the shaft; a first bearing and a second bearing arranged axially above and below, respectively, the impeller cup; a first bearing support portion and a second bearing support portion arranged to support the first and second bearings, respectively; and a first housing and a second housing arranged on axially upper and lower sides, respectively. The first and second housings are joined to each other at an axial level higher than an axial position of a joint between the second housing and a second joining portion arranged to join the second housing and the second bearing support portion to each other.

1 . A blower fan comprising:
 an impeller including a substantially cylindrical impeller cup including a cover portion, and a plurality of blades arranged on an outer circumferential surface of the impeller cup;   a shaft fixed directly or indirectly to the impeller cup, and including an end arranged to project axially upward from the cover portion of the impeller cup;   a rotor magnet fixed directly or indirectly to the shaft;   a first bearing arranged axially above the cover portion of the impeller cup, and arranged to support the shaft such that the shaft is rotatable with respect to the stator;   a first bearing support portion arranged to support the first bearing;   a first housing arranged radially outward of the impeller on an axially upper side;   a first joining portion arranged to join the first housing and the first bearing support portion to each other;   a second bearing arranged axially below the cover portion of the impeller cup, and arranged to support the shaft such that the shaft is rotatable with respect to the stator;   a second bearing support portion arranged to support the second bearing;   a second housing arranged radially outward of the impeller on an axially lower side;   a second joining portion arranged to join the second housing and the second bearing support portion to each other;   a stator arranged radially outward of the rotor magnet and opposite the rotor magnet; and   a stator support portion arranged to support the stator; wherein   the first and second housings are joined to each other at an axial level higher than an axial position of a joint between the second joining portion and the second housing.   
     
     
         2 . The blower fan according to  claim 1 , wherein
 the impeller cup includes a recessed portion defined in a central portion of the cover portion; and   at least a lower end of the first bearing support portion is arranged inside the recessed portion.   
     
     
         3 . The blower fan according to  claim 1 , wherein
 the first housing, the first bearing support portion, and the first joining portion are integral with one another; and   the second housing, the second bearing support portion, and the second joining portion are integral with one another.   
     
     
         4 . The blower fan according to  claim 3 , wherein the first bearing support portion and the second bearing support portion are defined by metallic members coupled to the first housing and the second housing, respectively, by being at least partially embedded within the first housing and the second housing. 
     
     
         5 . The blower fan according to  claim 1 , wherein the second joining portion defines a stationary vane. 
     
     
         6 . The blower fan according to  claim 1 , further comprising a substantially cylindrical rotor holder fixed to the shaft, wherein the rotor magnet is fixed to an outside wall of the rotor holder. 
     
     
         7 . The blower fan according to  claim 6 , wherein the rotor holder is coupled to the impeller cup by being at least partially embedded within the impeller cup. 
     
     
         8 . The blower fan according to  claim 3 , wherein the second housing, the second bearing support portion, the second joining portion, and the stator support portion are integral with one another.