Air-conditioning blower motor unit

1. A blower comprising:

a fan case configured to be connected to a duct constituting an air conditioner for a vehicle:

a blower fan configured to be housed in the fan case;

a brushless motor which includes an output shaft coupled with the blower fan, a stator, and a gas flow channels through which an introducing air passes, wherein the stator is provided with a stator core, an upper insulator, a lower insulator, and windings;

a base frame configured to support the output shaft and the stator core;

a circuit board configured to allow the brushless motor to be driven by a supply of an electric power; and

a casing which includes an upper casing section and a lower casing section, and is attached to the fan case, wherein

the upper casing section comprises:

an air introduction opening which is on a side of the blower fan, is open to the fan case, and introduces an air within the fan case to an inside of the casing, the air being sent by the blower fan through the duct to the fan case and having a positive pressure, and

a central opening which is provided around the output shaft and discharges the air, which is introduced through the air introduction opening, from the inside of the casing to the fan case,

the lower casing section is provided at a position lower than the output shaft, and

the upper casing section and the lower casing section are configured to be combined with each other so as to:

form a gas guide section which is an air conducting passage communicating with the air introduction opening, and thereby communicating with a downstream in an air-sending direction in the fan case, and

house the brushless motor, the circuit board, and the base frame, wherein

the lower casing section of the casing comprises:

a bottom section communicating with the gas guide section and guiding the introducing air so as to pass around a bottom of the output shaft, and

a wall section communicating with the bottom section and guiding the introducing air to the central opening, wherein

the base frame comprises:

a circuit board fixture to which the circuit board is fixed such that substantially an entire surface of the circuit board faces the introducing air passing along the bottom section, and

a plurality of base frame openings provided within the streamlines of the introducing air guided by the wall section toward the central opening such that the introducing air passes the stator, and wherein

the circuit board is disposed at a position eccentric with respect to the output shaft of the brushless motor toward the air introduction opening,

the circuit board is fixed to the circuit board fixture of the base frame so as to be spaced from the casing, in a range of the streamlines of the introduction air flowing from the air introduction opening to the central opening,

the circuit board is formed in substantially semicircular shape so as to allow the introducing air passing toward the base frame openings, and

the circuit board is disposed within the streamlines between the air introduction opening of the casing and the output shaft.

2. The blower according to claim 1 , further comprising a heat sink member provided on the base frame at a position within the streamlines of the introduction air flowing from the air introduction opening to the central opening, wherein:

the heat sink member is partially exposed outside the casing; and

the heat sink member is adjacent to the circuit board to allow thermal conduction.

3. The blower according to claim 1 ,

wherein the wall section comprises a guide wall section which is a standing wall section that rises from the bottom section of the lower casing section and becomes a tapered shape to form a tapered surface at a position opposite to the gas guide section.

4. The blower according to claim 1 , wherein the base frame is a unitary structure.