Damped assembly

Abstract

In a nozzle guide vane assembly for a compressor or fan stage of a gas turbine engine each of the guide vanes is held in position between an outer casing and an annular inner ring by means of a rubber boot or collar at each end of the vane. Operational experience has shown potential for these assemblies to resonate within the engine, the cause of which is traced to the stiffness of the rubber collar. The present invention proposes as a solution a modified form of collar in which a stiffening plate is either bonded to the surface of the rubber or is incorporated into the construction during the rubber vulcanisation process. Alternatively or in addition the properties of the material from which the boots are moulded may be modified by the inclusion of chopped fibres of a range of materials.

1 . A damped assembly comprising at least one member carried in a supporting structure by at least one end of the member located in a socket formed in the supporting structure with an intermediate collar of resilient material interposed therebetween wherein the collar of resilient material includes stiffening means.  
   
   
       2 . A damped assembly as claimed in  claim 1  wherein the stiffening means includes a metal plate.  
   
   
       3 . A damped assembly as claimed in  claim 2  wherein the metal plate is bonded to a surface of the collar.  
   
   
       4 . A damped assembly as claimed in  claim 2  wherein the stiffening means and the collar are formed as a unitary member.  
   
   
       5 . A damped assembly as claimed in  claim 1  wherein the properties of the resilient material of which the intermediate collar is comprised are modified by the inclusion of a further material to increase the stiffness of the resilient material.  
   
   
       6 . A damped assembly as claimed in  claim 5  wherein the further material is selected from the group of materials including carbon fibre, glass fibre Kevlar fibre and glass micro-spheres.