Patent ID: 7914383

Claim:
A rotorcraft transmission system comprising: a supercritical transmission shaft ( 21 ) that has two longitudinal ends, each of which is fitted with a respective connection member; an active magnetic damper between the connection members, the active magnetic damper having electromagnetic induction members ( 30 , 31 ) that extend around the supercritical shaft and that co-operate therewith to determine a radial clearance ( 33 ), and two stator shells ( 60 , 61 ) around the induction members and in mutual contact along a diametrical plane containing a longitudinal axis ( 22 ) of the supercritical shaft; and two additional radial dampers ( 35 ) at longitudinal ends of at least one of the two shells, the two radial dampers disposed on the shaft with radial spacing ( 39 ) that is smaller than the radial clearance, each of said additional radial dampers comprising a rod that secures a respective one of said two stator shells of said active magnetic damper, a stator portion ( 36 ) through which the rod extends and that is adapted to be secured to a structure ( 25 ) of a rotorcraft, and a floating portion ( 37 ) movable radially relative to the stator portion and surrounding said transmission shaft with said radial spacing ( 39 ), said floating portion ( 37 ) having pads ( 50 - 53 ) with annular surfaces ( 40 , 73 ) and said stator portion ( 36 ) having disks ( 63 - 66 ) with surfaces ( 41 ) opposing said annular surfaces, wherein damping by said additional radial damper results from friction between said annular surfaces ( 40 , 73 ) and said surfaces ( 41 ) opposing said annular surfaces.