Patent ID: 7137786

Claim:
A tilting power transmission gearbox ( 1 ), designed to drive in rotation at least one driven part ( 14 ) about an axis of rotation (A—A) being able to swivel about a tilting axis (B—B), more or less perpendicular to said axis of rotation (A—A) of said driven device ( 14 ), such as the tilting rotor of a convertible aircraft with said transmission gearbox ( 1 ) having a housing ( 2 ) mounted to tilt with respect to two fixed and rigid lateral parts ( 17 ) of a support ( 18 ) via two coaxial bearings ( 19 ) about said tilting axis (B—B) and at intervals from one another along said tilting axis (B—B), characterised in that the two bearings ( 19 ) are plain bearings each of which includes: a fixed part ( 20 ), integral with respectively one of the two lateral parts ( 17 ) of said support ( 18 ), and including a sleeve ( 20 a ) that is more or less cylindrical and that is approximately coaxial with sleeve ( 20 a ) of said fixed part ( 20 ) of the other bearing ( 19 ), around tilting axis(B—B). a swivelling part ( 21 ) integral with said tilting casing ( 2 ) and including a more or less cylindrical annular trunnion ( 21 a ) mounted to swivel about said sleeve ( 20 a ) of fixed part ( 20 ) of said bearing ( 19 ) and more or less coaxial with the corresponding trunnion ( 21 a ) of the swivelling part ( 21 ) of the other bearing ( 19 ), and a wear ring ( 22 ) comprising a cylindrical tubular part ( 22 a ), engaged axially between said sleeve ( 20 a ) of said fixed part ( 20 ) and said trunnion ( 21 a ) of said mobile part ( 21 ), and a radial collar ( 22 b ), protruding radially toward the outside of said tubular part ( 22 a ) and with respect to its axis, and integral with an axial end of said tubular part ( 22 a ) which is turned towards said corresponding lateral part ( 17 ) of support ( 18 ).