Fan

Abstract

A fan includes blades and a motor. The motor includes a rotor holder; a shaft; a sleeve; a holder; and a thrust plate. A radial bearing portion arranged to support the shaft in a radial direction is defined in a radial gap defined between the shaft and the sleeve. A lower seal portion having a lower surface of a lubricating oil defined therein is defined between the thrust plate and the holder, while an upper seal portion having an upper surface of the lubricating oil defined therein is defined between the holder and the sleeve. The holder includes a connection channel defining portion arranged to define a connection channel to connect an upper space defined between the upper seal portion and an inside of the rotor holder with a lower space at which the lower seal portion is arranged.

What is claimed is: 
     
         1 . A fan comprising:
 a plurality of blades; and   a motor arranged to rotate the blades about a central axis; wherein   the motor includes:
 a stationary portion including a stator; 
 a rotating portion including a rotor magnet arranged radially outside the stator; and 
 a bearing mechanism arranged to support the rotating portion such that the rotating portion is rotatable with respect to the stationary portion; 
   the rotating portion includes a rotor holder arranged in a shape of a covered cylinder, and including an outer circumferential surface on which the blades are arranged;   the bearing mechanism includes:
 a shaft; 
 a sleeve in which the shaft is inserted; 
 a holder arranged to hold the sleeve; and 
 a thrust plate fixed to a lower end portion of the shaft on a lower side of the sleeve; 
   the shaft and the sleeve are arranged to together define a radial gap therebetween, the radial gap including a radial bearing portion arranged to support the shaft in a radial direction;   the thrust plate and the holder are arranged to together define a lower seal portion therebetween, the lower seal portion having a lower surface of a lubricating oil defined therein, while the holder and the sleeve are arranged to together define an upper seal portion therebetween, the upper seal portion having an upper surface of the lubricating oil defined therein; and   the holder includes a connection channel defining portion arranged to define a connection channel to connect an upper space defined between the upper seal portion and an inside of the rotor holder with a lower space at which the lower seal portion is arranged.   
     
     
         2 . The fan according to  claim 1 , wherein a lower surface of the sleeve and an upper surface of the thrust plate are arranged to together define a lower thrust gap therebetween, the lower thrust gap including a lower thrust bearing portion arranged to support the thrust plate in an axial direction. 
     
     
         3 . The fan according to  claim 1 , wherein
 an outer circumferential surface of the sleeve and an inner circumferential surface of the holder are arranged to together define an upper seal gap therebetween, the upper seal gap being arranged to gradually increase in radial width with increasing height, the upper seal gap including the upper seal portion defined therein; and   the upper space is a space enclosed by the sleeve, the holder, the shaft, and the rotor holder.   
     
     
         4 . The fan according to one of  claims 1  and  3 , wherein an upper end opening of the connection channel defining portion is defined in the inner circumferential surface of the holder. 
     
     
         5 . The fan according to one of  claims 1  and  3 , wherein a lower end opening of the connection channel defining portion is defined in the inner circumferential surface of the holder. 
     
     
         6 . The fan according to one of  claims 1  and  3 , wherein
 the bearing mechanism further includes a thrust cap arranged to close a lower opening of the holder; and 
 the lower space is arranged on an upper side of the thrust cap. 
 
     
     
         7 . The fan according to  claim 6 , wherein
 the thrust cap includes a cap through hole arranged to extend in a vertical direction through the thrust cap; and   the lower space is connected with the upper space through the cap through hole and the connection channel.   
     
     
         8 . The fan according to  claim 7 , further comprising a seal member arranged on a lower side of the thrust cap to define a space between the thrust cap and the seal member, wherein
 the connection channel includes:
 a holder groove arranged to extend in the vertical direction in an outer circumferential surface of the holder on a radially inner side of an inner circumferential surface of the stator; and 
 a holder through hole arranged to extend through the holder from the holder groove to a lower end of the holder; and 
   the lower space is connected with the upper space through the cap through hole, the space defined between the thrust cap and the seal member, the holder through hole, and the holder groove.   
     
     
         9 . The fan according to any one of  claims 1  to  3 , wherein
 a plurality of connection channel defining portions are provided; and 
 each of the connection channel defining portions is arranged to define one of a plurality of connection channels arranged at regular intervals in a circumferential direction. 
 
     
     
         10 . A fan comprising:
 a plurality of blades; and   a motor arranged to rotate the blades about a central axis; wherein   the motor includes:
 a stationary portion including a stator; 
 a rotating portion including a rotor magnet arranged radially outside the stator; and 
 a bearing mechanism arranged to support the rotating portion such that the rotating portion is rotatable with respect to the stationary portion; 
   the rotating portion includes a rotor holder arranged in a shape of a covered cylinder, and including an outer circumferential surface on which the blades are arranged;   the bearing mechanism includes:
 a shaft; 
 a sleeve in which the shaft is inserted; 
 a holder arranged to hold the sleeve; and 
 a thrust plate fixed to a lower end portion of the shaft on a lower side of the sleeve; 
   the holder includes:
 a cylindrical first holder arranged to cover an outer circumferential surface of the sleeve and an outer circumferential surface of the thrust plate, the first holder including an annular upper portion arranged to project radially inward on an upper side of the sleeve; and 
 a second holder including an inner circumferential surface having an outer circumferential surface of the first holder fixed thereto, the second holder having the stator arranged on a radially outer side thereof; 
   the shaft and the sleeve are arranged to together define a radial gap therebetween, the radial gap including a radial bearing portion arranged to support the shaft in a radial direction;   the thrust plate and the first holder are arranged to together define a lower seal portion therebetween, the lower seal portion having a lower surface of a lubricating oil defined therein, while the shaft and the annular upper portion are arranged to together define an upper seal portion therebetween, the upper seal portion having an upper surface of the lubricating oil defined therein; and   the second holder includes a connection channel defining portion arranged to define a connection channel to connect an upper space defined between the upper seal portion and an inside of the rotor holder with a lower space at which the lower seal portion is arranged.   
     
     
         11 . The fan according to  claim 10 , wherein a lower surface of the sleeve and an upper surface of the thrust plate are arranged to together define a lower thrust gap therebetween, the lower thrust gap including a lower thrust bearing portion arranged to support the thrust plate in an axial direction. 
     
     
         12 . The fan according to  claim 10 , wherein
 an inner circumferential surface of the annular upper portion and an outer circumferential surface of the shaft are arranged to together define an upper seal gap therebetween, the upper seal gap being arranged to gradually increase in radial width with increasing height, the upper seal gap including the upper seal portion defined therein; and   the upper space is a space enclosed by the shaft, the holder, and the rotor holder.   
     
     
         13 . The fan according to any one of  claims 10  to  12 , wherein an upper end opening of the connection channel defining portion is defined in the inner circumferential surface of the second holder. 
     
     
         14 . The fan according to any one of  claims 10  to  12 , wherein a lower end opening of the connection channel defining portion is defined in the inner circumferential surface of the second holder. 
     
     
         15 . The fan according to any one of  claims 10  to  12 , wherein
 the bearing mechanism further includes a thrust cap arranged to close a lower opening of the holder; and 
 the lower space is arranged on an upper side of the thrust cap. 
 
     
     
         16 . The fan according to  claim 15 , wherein
 the thrust cap includes a cap through hole arranged to extend in a vertical direction through the thrust cap; and   the lower space is connected with the upper space through the cap through hole and the connection channel.   
     
     
         17 . The fan according to  claim 16 , further comprising a seal member arranged on a lower side of the thrust cap to define a space between the thrust cap and the seal member, wherein
 the connection channel includes:
 a holder groove arranged to extend in the vertical direction in an outer circumferential surface of the second holder on a radially inner side of an inner circumferential surface of the stator; and 
 a holder through hole arranged to extend through the second holder from the holder groove to a lower end of the second holder; and 
   the lower space is connected with the upper space through the cap through hole, the space defined between the thrust cap and the seal member, the holder through hole, and the holder groove.   
     
     
         18 . The fan according to any one of  claims 10  to  12 , wherein
 a plurality of connection channel defining portions are provided; and 
 each of the connection channel defining portions is arranged to define one of a plurality of connection channels arranged at regular intervals in a circumferential direction. 
 
     
     
         19 . A fan comprising:
 a plurality of blades; and   a motor arranged to rotate the blades about a central axis; wherein   the motor includes:
 a stationary portion including a stator; 
 a rotating portion including a rotor magnet arranged radially outside the stator; and 
 a bearing mechanism arranged to support the rotating portion such that the rotating portion is rotatable with respect to the stationary portion; 
   the stationary portion includes a bushing arranged to hold the stator on a radially outer side thereof;   the rotating portion includes a rotor holder arranged in a shape of a covered cylinder, and including an outer circumferential surface on which the blades are arranged;   the bearing mechanism includes:
 a shaft; 
 a bearing portion in which the shaft is inserted; 
 a thrust plate fixed to a lower end portion of the shaft on a lower side of the sleeve; 
 a thrust portion arranged to extend radially outward from an upper portion of the shaft; and 
 a rotor cylindrical portion arranged to extend axially downward from the thrust portion; 
   the shaft and the bearing portion are arranged to together define a radial gap therebetween, the radial gap including a radial bearing portion arranged to support the shaft in a radial direction;   the thrust plate and the bearing portion are arranged to together define a lower seal portion therebetween, the lower seal portion having a lower surface of a lubricating oil defined therein, while the bearing portion and the rotor cylindrical portion are arranged to together define an upper seal portion therebetween, the upper seal portion having an upper surface of the lubricating oil defined therein; and   the bushing includes a connection channel defining portion arranged to define a connection channel to connect an upper space defined between the upper seal portion and an inside of the rotor holder with a lower space at which the lower seal portion is arranged.   
     
     
         20 . The fan according to  claim 19 , wherein a lower surface of the bearing portion and an upper surface of the thrust plate are arranged to together define a lower thrust gap therebetween, the lower thrust gap including a lower thrust bearing portion arranged to support the thrust plate in an axial direction. 
     
     
         21 . The fan according to one of  claims 19  and  20 , wherein
 the bearing portion includes:
 a tubular sleeve; and 
 a holder arranged to cover an outer circumferential surface of the sleeve; and 
 
 an upper surface of the sleeve and a lower surface of the thrust portion are arranged to together define an upper thrust bearing portion therebetween, the upper thrust bearing portion being arranged to support the thrust portion in an axial direction. 
 
     
     
         22 . The fan according to one of  claims 19  and  20 , wherein a lower end opening of the connection channel defining portion is defined in an inner circumferential surface of the bushing. 
     
     
         23 . The fan according to one of  claims 19  and  20 , wherein
 the bearing mechanism further includes a thrust cap arranged to close a lower opening of the bushing; and 
 the lower space is arranged on an upper side of the thrust cap. 
 
     
     
         24 . The fan according to  claim 23 , wherein
 the thrust cap includes a cap through hole arranged to extend in a vertical direction through the thrust cap; and   the lower space is connected with the upper space through the cap through hole and the connection channel.   
     
     
         25 . The fan according to  claim 24 , further comprising a seal member arranged on a lower side of the thrust cap to define a space between the thrust cap and the seal member, wherein
 the connection channel includes:
 a bushing groove arranged to extend in the vertical direction in an outer circumferential surface of the bushing on a radially inner side of an inner circumferential surface of the stator; and 
 a bushing through hole arranged to extend through the bushing from the bushing groove to a lower end of the bushing; and 
   the lower space is connected with the upper space through the cap through hole, the space defined between the thrust cap and the seal member, the bushing through hole, and the bushing groove.   
     
     
         26 . The fan according to one of  claims 19  and  20 , wherein
 a plurality of connection channel defining portions are provided; and 
 each of the connection channel defining portions is arranged to define one of a plurality of connection channels arranged at regular intervals in a circumferential direction.