Device for end-to-end coupling of a supercritical transmission shaft, in particular for driving a rotorcraft rotor

A coupling device for end-to-end coupling between a supercritical transmission shaft and link shafts between which the transmission shaft is interposed, said coupling device comprising:

• coupling means for flexible end-to-end coupling between the ends of the transmission shaft and respectively with one and the other of the link shafts, providing freedom to move in angular deflection (B) about centers of motion (C1) for the transmission shaft relative to the axes of rotation (A) of the link shaft;
• damper means for damping the movement in angular deflection (B) of the transmission shaft relative to the axes of the link shafts;
• and
• at least one bearing for mounting the transmission shaft at one of its ends on a carrier structure, said bearing comprising a cage that housing at least one rolling member interposed between the transmission shaft and said carrier structure;
• wherein the damper means comprise at least one pair of friction members having spherical bearing surfaces that are incorporated in a said bearing and placed to press one towards the other via respective friction surfaces, a first friction member being securely engaged with the carrier structure and a second friction member being securely engaged with said cage, itself engaged on the transmission shaft to accompany it in its movement in angular deflection (B).