Conventionally, an example of a technique regarding an automotive AC generator of which an object is to reduce magnetic noises by reducing an incorrect magnetic flux amount flowing between claw-shaped magnetic poles adjacent to each other via teeth is disclosed and (refer to Japanese Patent Application Laid-Open Publication No. 2002-058220, for example).
The above automotive AC generator has air gap extended surfaces formed on outer diameter sides of the claw-shaped magnetic poles, and a circumferential center of the magnetic poles and a circumferential center of tip portions of the teeth are at the same radial positions.
Further, the tip portions of the teeth do not overlap with radially-outermost surfaces of the claw-shaped magnetic poles, and are configured to overlap with portions of the air gap extended surfaces.
When an air gap is indicated by δ, and a circumferential distance between the radially-outermost surface and the tip portion of the teeth is indicated by τ, it is configured that 0<τ<3δ.
However, even when the circumferential distance between the radially-outermost surface and the tip portion of the teeth is configured to be 0<τ<3δ, there is a problem that magnetic flux leakage flowing between each of the claw-shaped magnetic poles through the tip portion of the teeth exists.
Further, by areas of the radially-outermost surfaces of to the claw-shaped magnetic poles being reduced, magnetic resistance of a magnetic circuit increases, and there is a problem that the magnetic flux generated will decrease.
Furthermore, since the claw-shaped magnetic poles are not properly chamfered and portions where a variation of the magnetic flux is sharp exist, there is a problem that the magnetic noise increases.
USPTO Backgrounds
USPTO Backgrounds