Rotocraft rotor blade, has electromechanical actuator to pivot flap around hinge axis along wing span of blade and flap, and main ball joint prestressed in chord direction of flap by applying centrifugal forces on flap/ball joint assembly

摘要

#CMT# #/CMT# The blade has a main ball joint (30) with inner and outer casings (32, 33), and a shaft (31). A front part (33`) of the outer casing is connected to an electromechanical actuator (10). The actuator permits pivoting of a flap (5) around a virtual hinge axis (Y`) oriented along the wing span of the blade and flap. The shaft is perpendicular to the axis, where the axis is arranged at 25 percent of the chord of the flap while originating from a leading edge of the flap. The ball joint is prestressed in the chord direction by applying centrifugal forces on the flap/ball joint assembly. #CMT#USE : #/CMT# Used for a rotor to advance and lift a rotocraft (claimed). #CMT#ADVANTAGE : #/CMT# The ball joint is prestressed in the chord direction of the flap by applying centrifugal forces on the flap/ball joint assembly, thus canceling the clearance separating the inner and outer casings of the ball joint and hence limiting the premature wear of the ball joint irrespective of the other forces such as dynamic or aerodynamic or control forces. The assembly is therefore robust, and the flap does not require longitudinal axles or trunnion blocks for its pivoting, so that the risks of locking of the flap are limited. The electromechanical actuator permits pivoting of the flap around the virtual hinge axis to improve aeroacoustic, aerodynamic and vibratory performances of the blade. #CMT#DESCRIPTION OF DRAWINGS : #/CMT# The drawing shows a section of a rotor blade of a rotocraft. Y` : Virtual hinge axis 5 : Flap 10 : Electromechanical actuator 30 : Main ball joint 31 : Shaft 32, 33 : Inner and outer casings 33` : Front part.