Patent ID: 7358630

Claim:
A ventilating device ( 60 ) adapted to be fixed on a transverse end face ( 44 , 46 ) of an axial end of a rotor of a rotary electrical machine, of the type comprising: a first fan ( 62 a ) comprising a first central plate portion ( 64 a ), from which first blades ( 68 a ) extend radially outwardly; at least one second fan ( 62 b ) comprising a second central plate portion ( 64 b ), from which second blades ( 68 b ) extend radially outwardly; and a fan fastening mechanism for fastening the two fans ( 62 a , 62 b ), wherein each fan ( 62 a , 62 b ) has, extending radially outwards from its outer periphery, first branches ( 78 a ) and second branches ( 78 b ) respectively, and wherein at least some of the said branches carry a blade, and wherein the first fan 62 a has first branches ( 78 a ) extending radially outwardly from an outer periphery thereof and the second fan ( 62 b ) has second branches ( 78 b ) extending radially outwardly from an outer periphery thereof, wherein at least some of the first and second branches carry the first and second blades respecively, and wherein at least one first branch ( 78 a ) and at least one second branch ( 78 b ) include a first overlapping portion ( 78 a ) and a second overlapping portion ( 78 b ) superimposed on each other to define an overlap zone (Z), and in that the fan fastening mechanism ( 80 , 82 ) of the two fans are arranged at least partly in the said overlap zone (Z).