Patent ID: 6494680
Filing Date: 2002-12-17
Classification: B64C,F16F,Y10S

Abstract:
A rotorcraft rotor comprising a rotor head at which a hub intended to be driven in rotation about an axis of the rotor is connected to at least two rotor blades, the rotor also comprising a pendular vibration suppressor comprising at least two pendulums, each of which comprises at least one pendular body connected by at least one rigid arm to said hub so that each pendulum is driven by said hub in rotation about the rotor axis, and mounted so as to oscillate with respect to said hub via a pivoting connection about an axis of pendular movement which is spaced away from the center of inertia of the pendulum and from the axis of the rotor and is at a fixed distance from the rotor axis and is substantially perpendicular to a radial plane passing through the axis of the rotor and through the center of inertia of the corresponding pendulum without the possibility of the pendulum oscillating about an axis parallel to the axis of the rotor and concurrent with the axis of pendular movement so as to attenuate vibration generated by the movement of the rotor, wherein the mass and the inertia of each pendulum of a first group of at least two pendulums, and a lever arm between the center of inertia and the axis of pendular movement of said pendulum, and a radius of attachment between the axis of the pendular movement and the axis of the rotor, are chosen so that the natural frequency of the pendulum is tuned to attenuate coplanar moments, to (nb+1)&OHgr; or (nbâˆ’1)&OHgr; where n is an integer at least equal to 1, b is the number of rotor blades and &OHgr; is the rotational speed of the rotor.