Turbojet engine case, notably intermediate case

Abstract

The present invention relates to an annular case ( 20 ) of a multi-flow turbojet engine comprising a first element ( 22 ) forming a hub, a second element ( 24 ) forming a cylindrical casing, radially on the outside of and concentric with the first element, radial arms ( 23 ) connecting the first element ( 22 ) to the second element ( 24 ), at least part of said arms being structural and having an aerodynamic flow straightener vane profile, characterized in that it comprises a first ring sector ( 20 C) of the case and a second ring sector ( 20 T), the first ring sector being made of composite material and the second ring sector of metal, said radial arms ( 23 T) of the second ring sector ( 20 T) being structural.

1 . An annular case of a multi-flow turbojet engine comprising a first element forming a hub, a second element forming a cylindrical casing, radially on the outside of and concentric with the first element, radial arms connecting the first element to the second element, at least part of said arms being structural and having an aerodynamic flow straightener vane profile, said annular case further comprising a first ring sector of the case and a second ring sector, the first ring sector being made at least partially of composite material and the second ring sector of metal, said radial arms of the second ring sector being structural. 
     
     
         2 . The case according to  claim 1 , in which the first ring sector has a resin impregnated fibrous structure. 
     
     
         3 . The case according to  claim 2 , in which the first ring sector is of one piece and the radial arms of the first sector form flow straightener vanes. 
     
     
         4 . The case according to  claim 3 , in which the second ring sector is of one piece. 
     
     
         5 . The case according to  claim 4 , in which the second ring sector is a casting. 
     
     
         6 . The case according to  claim 4 , in which the second ring sector is made of titanium alloy. 
     
     
         7 . The case according to  claim 6 , in which the two ring sectors are joined together by bolting. 
     
     
         8 . The case according to  claim 7 , in which the two ring sectors are joined together using fishplates. 
     
     
         9 . The case according to  claim 8 , in which the second element of the second ring sector comprises attachment means for fixing the turbojet engine, on which the case is mounted, to the structure of an aircraft; the angle subtended at the center of the second ring sector being comprised between 30° and 120°. 
     
     
         10 . A multi-flow turbojet engine comprising an intermediate case at least partially incorporating a case according to  claim 1 .