Rotary-wing aircraft rotor having a compact articulated hub
AssigneeSociete Nationale Industrielle Aerospatiale
InventorJacques A. Aubry
Life of this patent
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Abstract
The invention relates to a rotary-wing aircraft rotor. The rotor comprises a hub 1 connected to each blade 7a by a rigid yoke 8-9 gripping the root of blade 7a and a spherical abutment 17 secured at its center C to radial arms 5a, 6a of hub 1 and bearing on its convex side against the inner end of yoke 8-9. According to the invention, an annular visco-elastic shock-absorber 20, constituting a frequency-matching device, is disposed between the yoke 8-9 associated with each blade 7a and the corresponding pitch control device 24-29. The invention is of use inter alia in the manufacture of fast helicopter rotors having a hub which is very compact and can therefore be easily streamlined.
Claims10
A rotary wing aircraft rotor comprising
- a compact articulated hub secured to a top part of a tubular strut rotating around a rotor rotation axis,
- at least two blades connected to said hub, said hub having for each blade a pair of superposed radial arms connected to a corresponding blade root by means of a single spherical laminar abutment including an alternating stack of rigid and elastomer strips in the forms of spherical caps secured together,
- a yoke including two rigid plates, the radial outer ends of which form a fork to which said corresponding blade root is secured by at least a pin wherein each of said two rigid yoke plates has a radial inner recessed part having a wide aperture, said radial inner recessed parts being held apart by means of at least one radial inner and one radial outer tubular spacers,
- and said spherical laminar abutment is fitted into said apertures of said yoke plates, with a concave portion of said spherical abutment being mounted on a radial outer rigid fitting prolonged towards the center of said spherical abutment by a radial outer component extending through said apertures and secured between the radial outer ends of said radial arms, and a convex portion of said spherical abutment being mounted on a radial inner rigid fitting bearing against the corresponding inner edges of said apertures of said yoke plates, and wherein, for each blade a flat annular visco-elastic shock-absorber is inserted between said corresponding two rigid yoke plates so as to surround said single spherical abutment,
- said flat annular visco-elastic shock absorber including an alternating stack of at least two rigid plates and at least one layer of a visco-elastic material having great rigidity and high remanence to deformation, each layer of said visco-elastic material being secured between and to two of said shock-absorber rigid plates,
- and said shock-absorber being disposed between and journaled on two arms of a stirrup-shaped component connected to a top end of a blade pitch control link so that beat or flap drag and pitch motions of each blade are allowed by elastic-deformation of said elastomer strips of said single spherical laminar abutment and that said shock absorber produces an elastic return and a damping action on the drag motion of said corresponding blade.
Dependencies are inferred from the claim text.