Patent attributes
The present invention relates to a fan wheel (11) for electrical machines, in particular for alternators of motor vehicles, with a fan disk (10) that, on its axially outwardly directed end face, has a number of fan blades (13, 18) distributed around the circumference in the shape of a circular ring, the fan blades extending away from the fan disk in the axial direction, so that cooling air beneath the fan blades can be drawn in axially and blown radially outwardly between air channels (20, 21) formed between them. One part (18) of each of the fan blades is joined in a fixed manner with the fan disk (10) via only its radially outward end section (18a), so that each inner end section (18b) is swiveled radially increasingly outwardly by a centrifugal force (22) occurring there as rotational speeds increase, to reduce the cooling air stream. To minimize not only the speed-dependent adaptation of the cooling air quantity to the cooling needs of the machine, but the flow noises as well, preferably only every second fan blade (18) is provided with an inner end section (18b) capable of being swiveled outwardly by centrifugal force (22), while the other, adjacent, first fan blades (13) are rigid along their entire length and are connected to the fan disk (10) in a fixed manner.
