Blower

1. A centrifugal blower, comprising:

a casing;

an impeller disposed within the casing; and

a motor arranged to rotate the impeller about a center axis, wherein

the casing includes an intake port opened toward a center of the impeller, an exhaust port positioned radially outward of the impeller and the motor, and a wind tunnel arranged to bring the intake port and the exhaust port into communication with each other and arranged to extend in a ring shape around the motor,

the motor includes a shaft disposed along the center axis, a rotor fixed to the impeller through the shaft, a stator disposed radially outward of the rotor and arranged to generate rotating magnetic fields between the stator and the rotor, and a stator housing arranged to hold the stator,

the stator housing includes a radial contact surface which makes contact with the casing in a radial direction, a circumferential contact surface which makes contact with the casing in a circumferential direction, an axial contact surface which makes contact with the casing in an axial direction, and a heat dissipating surface exposed to the wind tunnel,

the stator housing includes a plurality of salient portions on an outer circumferential surface thereof,

the casing includes a ring-shaped holder portion positioned radially inward of the wind tunnel,

the holder portion includes a plurality of through-holes or cutouts radially penetrating the holder portion,

the salient portions are respectively fitted to the through-holes or cutouts, and

each of the salient portions includes an outer end surface serving as the heat dissipating surface.

2. The blower of claim 1 , wherein the salient portions are disposed at a predetermined interval in the circumferential direction, and

each of the salient portions extends in the axial direction on an outer circumferential surface of the stator housing.

3. The blower of claim 1 , wherein the salient portions are disposed at a substantially regular interval in the circumferential direction.

4. The blower of claim 1 , wherein a radial outer surface of the holder portion and radial outer end surfaces of the salient portions are positioned on a substantially identical imaginary cylindrical plane.

5. The blower of claim 1 , wherein a material of the stator housing and a material of the casing differ from each other.

6. The blower of claim 5 , wherein the material of the stator housing is metal, and the material of the casing is a resin.

7. The blower of claim 6 , wherein the material of the stator housing is aluminum or an aluminum alloy.

8. The blower of claim 6 , wherein the casing is a resin-molded article that uses the stator housing as an insert part.

9. The blower of claim 1 , wherein the stator housing includes a housing body and a ring member positioned radially outward of the housing body,

the housing body and the ring member are arranged to make contact with each other, and

at least an outer circumferential surface of the ring member becomes the heat dissipating surface.

10. The blower of claim 9 , wherein the ring member includes a cylindrical portion disposed radially outward of the housing body so as to axially extend in a cylindrical shape and a flange portion protruding radially outward from the cylindrical portion.

11. The blower of claim 1 , further comprising:

a shaft disposed along the center axis and arranged to rotate together with the rotor and the impeller; and

a plurality of bearings interposed between the stator housing and the shaft,

wherein the bearings are disposed at the same side of the rotor in the axial direction.

12. The blower of claim 1 , which is configured to be used to feed an air to a respiratory tract of a sleeping human.