Automotive dynamoelectric machine

1. An automotive dynamoelectric machine comprising:

a rotor that is rotatably disposed inside a case by means of a shaft;

a stator that is disposed inside said case so as to surround an outer circumference of said rotor;

a heat-generating element that is mounted to an element mount surface of a heatsink and that controls rotation of said rotor electrically;

an air intake aperture and an air discharge aperture that are disposed through said case; and

a fan that is fixed to an axial end surface of said rotor and that rotates with said rotor so as to generate a cooling airflow that is sucked into said case through said air intake aperture and is discharged outside said case through said air discharge aperture,

wherein:

a large number of ventilating apertures that have a circular cross section are disposed through said heatsink so as to extend from an air intake apertured surface to an air discharge apertured surface so as to have aperture directions that are parallel to each other and parallel to said element mount surface; and

said heatsink is disposed such that said air intake apertured surface faces said air intake aperture and said aperture directions of said ventilating apertures are aligned in a direction of flow of said cooling airflow.

2. An automotive dynamoelectric machine according to claim 1 , wherein a cooling airflow introducing wall is disposed so as to guide said cooling airflow that has been sucked in through said air intake aperture toward said air intake apertured surface.

3. An automotive dynamoelectric machine according to claim 1 , wherein:

a rib is disposed on said case so as to lie across said air intake aperture and face said air intake apertured surface; and

ventilating apertures that face said rib are formed so as to have a diameter that is greater than a diameter of ventilating apertures that face said air intake aperture.

4. An automotive dynamoelectric machine according to claim 1 , wherein:

said heat-generating element is mounted to a single element mount surface other than said air intake apertured surface and said air discharge apertured surface of said heatsink; and

said ventilating apertures are formed so as to be arrayed in a staggered pattern in a cross section of said heatsink that is perpendicular to said aperture directions.

5. An automotive dynamoelectric machine according to claim 1 , wherein said heat-generating element is mounted to at least two element mount surfaces other than said air intake apertured surface and said air discharge apertured surface of said heatsink.

6. An automotive dynamoelectric machine according to claim 1 , wherein:

said heat-generating element is mounted to a single element mount surface other than said air intake apertured surface and said air discharge apertured surface of said heatsink; and

said ventilating apertures are formed so as to have diameters that increase as distance increases in a direction that is perpendicular to said element mount surface.

7. An automotive dynamoelectric machine according to claim 1 , wherein:

said heat-generating element is mounted to a single element mount surface other than said air intake apertured surface and said air discharge apertured surface of said heatsink; and

said ventilating apertures are formed such that spacing between adjacent ventilating apertures becomes narrower as distance increases in a direction that is perpendicular to said element mount surface.

8. An automotive dynamoelectric machine according to claim 1 , wherein said heatsink is formed such that a cross-sectional area that is perpendicular to said aperture direction is greater downstream in said direction of flow of said cooling airflow than upstream.