Patent ID: 8517685

Claim:
A device for reducing the vibration of a rotorcraft main rotor provided with a hub and a plurality of blades, the device having a plurality of heavy elements, a support with a pair of second openings per heavy element, a plurality of rollers, each heavy element including two first openings that are respectively at least partially in registration with the pair of second openings of the support, each roller in the plurality of rollers passing through a first opening and a second opening at least partially in registration with each other in order to attach a heavy element to the support, link means for connecting the support to the hub, a drive shaft and drive means rotating at a first speed of rotation (V 1 ) greater than a second speed of rotation (V 2 ) of the hub, the drive shaft being constrained to rotate about an axis of rotation (AX 1 ) with the support, a link member connecting the link means to the support the link member enabling the support to rotate about the axis of rotation (AX 1 ) relative to the link means, and a protective casing provided with a bottom fairing hermetically fastened to an outer shoulder of the link means, the casing having a top fairing fastened to the bottom fairing to form a closed container, the top fairing including at least one sloping plane directed towards a roller, wherein the casing is hermetically fastened to the link means so as to be constrained to rotate with the link means about the axis of rotation (AX 1 ), the casing covering the support and an element fastened to the support by the rollers, the casing being partially filled with a lubricant.