Resonator device for damping the vibrations of a rotor of a rotary-wing aircraft

A resonator device for damping the vibrations of a rotary-wing aircraft rotor having a shaft presenting a top hollow part (14) and supporting a hub (1) to which at least two blades extending radially are attached,

• said resonator device comprising a substantially annular weight (4) disposed concentrically of the rotor axis (A) and supported substantially without bending by at least three helical springs (5a, 5b, 5c) whose axes radiate in directions distributed regularly around the rotor axis (A) and which are radially biased in said directions, said biased springs (5a, 5b, 5c), applying statically balanced centrifugal thrusts to said annular weight (4), the annular weight (4) being bell-shaped and presenting an annular skirt-like part (4a) and a flat top member (4b), said skirt-like part (4a) being concentric of a spindle (2) axially extending the rotor-shaft (14) above a rigid central part of said hub (1), and said flat top member (4b) extending transversely of said spindle (2),
• wherein the inner end of each said spring (5a, 5b, 5c) bears directly on said spindle (2) and the outer end of each said spring (5a, 5b, 5c) bears directly on said skirt-like part (4a), and wherein said spindle (2) is tubular and open at both its ends, a rod (15) extending through said spindle (2) and having one end rigidly secured to the central area of said flat top-member (4b) of annular weight (4), the other end of said rod (15) extending into said top hollow part (14) of said rotor shaft and being internally connected to said shaft.