Blade retention bearing for helicopter rotor

Claim 1

An articulated rotor system for a helicopter and comprising a hub adapted for mounting to rotate about an axis, said hub having a bearing socket including an end wall at the radial outer end of said socket, said end wall having an aperture therethrough and a generally radially inwardly facing bearing surface surrounding said aperture, a rotor blade having a shaft concentric with the blade pitch change axis, said shaft extending through said aperture and into said socket, bearing means contained within said socket for connecting said blade to said hub and supporting said blade for articulated movement relative to said hub, said bearing surface being defined by a plurality of facets tangent to a spherical surface of revolution having its center at the intersection of said blade lead-lag axis and said blade flapping axis, said bearing means including a spherical, laminated elastomeric bearing having the spherically faced laminates thereof centered about the intersection of the blade lead-lag axis and the blade flapping axis, said laminates being annular in shape and receiving said shaft therethrough in spaced relation to said laminates, said spherical bearing having an outer end member attached to the outer lamination of said bearing and having a radially outwardly facing seating surface, said seating surface before assembly being defined by a plurality of additional facets complementing the facets defining said bearing surface, and means for releasably retaining said bearing means in assembly with said hub with said additional facets defining said seating surface in complimentary face-to-face engagement with said facets defining said bearing surface.