Blower fan

A blower fan comprising:

• a plurality of blades arranged in a circumferential direction about a central axis extending in a vertical direction;
• and
• a motor portion arranged to rotate the blades about the central axis;
• wherein
• the motor portion includes:
• a stationary portion;
• and
• a rotating portion supported to be rotatable with respect to the stationary portion, and arranged to have the blades fixed thereto;
• the stationary portion includes:
• a stator;
• a bearing portion;
• and
• an annular holding portion arranged to have the stator fixed to an outer circumferential surface thereof and to have the bearing portion fixed to an inner circumferential surface thereof;
• the rotating portion includes:
• a central rotating portion supported by the bearing portion;
• an annular cup portion fixed to the central rotating portion radially outside the central rotating portion;
• and
• a rotor magnet fixed to the cup portion, and arranged radially outside the stator;
• the central rotating portion includes:
• a shaft inserted in the bearing portion, and arranged to rotate about the central axis relative to the bearing portion;
• a bearing opposing portion arranged to extend radially outward from an upper end of the shaft;
• and
• a cylindrical seal portion arranged to extend downward from the bearing opposing portion radially outside the bearing portion;
• the cup portion includes:
• a cylindrical cup inner wall portion fixed to an outer circumferential surface of the cylindrical seal portion;
• a cup top plate portion arranged to extend radially outward from an upper end portion of the cup inner wall portion;
• and
• a cylindrical cup outer wall portion arranged to extend downward from an outer edge portion of the cup top plate portion;
• an inner circumferential surface of the cylindrical seal portion and an outer circumferential surface of the bearing portion are arranged to together define a seal gap therebetween, the seal gap including a seal portion having a surface of a lubricating oil defined therein;
• an inner circumferential surface of the bearing portion and an outer circumferential surface of the shaft are arranged to together define a radial gap therebetween, the radial gap including a radial bearing portion arranged to radially support the shaft;
• a lower surface of the bearing opposing portion and an upper surface of the bearing portion are arranged to together define a gap therebetween, and the lubricating oil is arranged in this gap;
• the shaft, the bearing opposing portion, and the cylindrical seal portion are defined by a single continuous electrically conductive member;
• the cup inner wall portion, the cup top plate portion, and the cup outer wall portion are defined single continuous insulating member;
• and
• the cup inner wall portion and the holding portion are opposed to each other in the vertical direction with an annular horizontal gap intervening therebetween, radially between the cylindrical seal portion and the stator.