Rotating electrical machine

1. An electrical rotating machine comprising:

a rotor which has a rotor winding and creates magnetic poles upon energization thereof;

a stator which is disposed to face the rotor;

a housing which retains the rotor and the stator therein;

a bearing through which the rotor is retained by the housing to be rotatable;

a plurality of air inlets which are formed in a wall of the housing and through which cooling air enters the housing to cool the bearing;

a plurality of air outlets which are formed in the wall of the housing and through which the cooling air is discharged outside the housing;

a plurality of spokes which extend in a radial direction of the housing to define the air inlets in the wall of the housing and isolate the air inlets from each other in a circumferential direction of the housing; and

heat sinks, each of which is equipped with fins, the fins of each of the heat sinks protruding in an axial direction of the rotor from a surface of a respective one of the spokes, wherein

the surface has a plane that is perpendicular to the axial direction of the rotor, and

the fins axially extend in a direction that is parallel to the axial direction.

2. The electrical rotating machine as set forth in claim 1 , wherein the fins of each of the heat sinks include an outer fin and an inner fin which is located inside the outer fin in a radial direction of the housing, and wherein the outer fin has a height protruding from the spoke which is greater than or equal to a height of the inner fin.

3. The electrical rotating machine as set forth in claim 1 , wherein the bearing is secured to the housing through a cushioning member configured to absorb a change in volume of at least one of the bearing and the housing which arises from thermal expansion thereof.

4. The electrical rotating machine as set forth in claim 1 , wherein each of the fins of the heat sinks has opposed major surfaces which are exposed to one of the air inlets and extend parallel to a flow of the cooling air entering the air inlet.

5. The electrical rotating machine as set forth in claim 1 , wherein each of the spokes extends from the bearing and is exposed to a flow of the cooling air entering a corresponding one of the air inlet to minimize transfer of heat from the housing to the bearing.

6. An electrical rotating machine comprising:

a rotor which has a rotor winding and creates magnetic poles upon energization thereof;

a stator which is disposed to face the rotor;

a housing which retains the rotor and the stator therein;

a bearing through which the rotor is retained by the housing to be rotatable;

a plurality of air inlets which are formed in a wall of the housing and through which cooling air enters the housing to cool the bearing;

a plurality of air outlets which are formed in the wall of the housing and through which the cooling air is discharged outside the housing after cooling the bearing;

a plurality of spokes which extend in a radial direction of the housing to define the air inlets in the wall of the housing and isolate the air inlets from each other in a circumferential direction of the housing; and

heat sinks each of which is equipped with fins, each of the heat sinks being disposed on a respective one of the spokes, the fins of each of the heat sinks protruding inward into a corresponding one of the air inlets from a corresponding one of the spokes in a direction perpendicular to a length of the spoke, the fins of each of the heat sinks including an outer fin and an inner fin which is located inside the outer fin in a radial direction of the housing, the outer fin having a height protruding from the spoke which is greater than a height of the inner fin.

7. An electrical rotating machine comprising:

a rotor which has a rotor winding and creates magnetic poles upon energization thereof;

a stator which is disposed to face the rotor;

a housing which retains the rotor and the stator therein;

a bearing through which the rotor is retained by the housing to be rotatable;

a plurality of air inlets which are formed in a wall of the housing and through which cooling air enters the housing to cool the bearing;

a plurality of air outlets which are formed in the wall of the housing and through which the cooling air is discharged outside the housing after cooling the bearing;

a plurality of spokes which extend in a radial direction of the housing to define the air inlets in the wall of the housing and isolate the air inlets from each other in a circumferential direction of the housing; and

heat sinks each of which is equipped with fins, each of the heat sinks being disposed on a respective one of the spokes, the fins of each of the heat sinks protruding from a respective one of the spokes, and the fins of each of the heat sinks protruding inward into a corresponding one of the air inlets from a corresponding one of the spokes in a direction perpendicular to a length of the spoke,

wherein the housing has disposed thereon an electrical device which is located outside one of the spokes in a radial direction of the housing.

8. The electrical rotating machine as set forth in claim 7 , wherein the electrical device is located closer to the air inlets than to the air outlets.

9. The electrical rotating machine as set forth in claim 7 , wherein the housing includes a front housing which is of a hollow cylindrical shape with a bottom and a rear housing which is of a hollow cylindrical shape with a bottom, and wherein the rear housing has the air outlets formed in a side wall thereof and also has the air inlets formed in a bottom wall thereof, the electrical device being mounted on the bottom wall of the rear housing.

10. An electrical rotating machine comprising:

a rotor which has a rotor winding and creates magnetic poles upon energization thereof;

a stator which is disposed to face the rotor;

a housing which retains the rotor and the stator therein;

a bearing through which the rotor is retained by the housing to be rotatable;

a plurality of air inlets which are formed in a wall of the housing and through which cooling air enters the housing to cool the bearing;

a plurality of air outlets which are formed in the wall of the housing and through which the cooling air is discharged outside the housing after cooling the bearing;

a plurality of spokes which extend in a radial direction of the housing to define the air inlets in the wall of the housing and isolate the air inlets from each other in a circumferential direction of the housing; and

heat sinks, each of which is equipped with fins, each of the heat sinks being disposed on a respective one of the spokes, the fins of each of the heat sinks protruding from a respective one of the spokes, and the fins of each of the heat sinks protruding in an axial direction of the rotor from a surface of a respective one of the spokes,

wherein the housing has disposed thereon an electrical device which is located outside one of the spokes in a radial direction of the housing.

11. The electrical rotating machine as set forth in claim 10 , wherein the electrical device is located closer to the air inlets than to the air outlets.

12. The electrical rotating machine as set forth in claim 10 , wherein the housing includes a front housing which is of a hollow cylindrical shape with a bottom and a rear housing which is of a hollow cylindrical shape with a bottom, and wherein the rear housing has the air outlets formed in a side wall thereof and also has the air inlets formed in a bottom wall thereof, the electrical device being mounted on the bottom wall of the rear housing.

13. The electrical rotating machine as set forth in claim 6 , wherein the bearing is secured to the housing through a cushioning member configured to absorb a change in volume of at least one of the bearing and the housing which arises from thermal expansion thereof.

14. The electrical rotating machine as set forth in claim 6 , wherein each of the fins of the heat sinks has opposed major surfaces which are exposed to one of the air inlets and extend parallel to a flow of the cooling air entering the air inlet.

15. The electrical rotating machine as set forth in claim 6 , wherein each of the spokes extends from the bearing and is exposed to a flow of the cooling air entering a corresponding one of the air inlet to minimize transfer of heat from the housing to the bearing.