Pitch change mechanism for a fan of a gas turbine engine

Abstract

A gas turbine engine including: a turbomachine having a compressor section, a combustion section, and a turbine section arranged in serial flow order; a fan defining a fan axis and comprising a plurality of fan blades rotatable about the fan axis; and a pitch change mechanism operable with the plurality of fan blades, the pitch change mechanism including a plurality of linkages, the plurality of linkages including a first linkage coupled to a first fan blade of the plurality of fan blades and a second linkage coupled to a second fan blade of the plurality of fan blades; and a non-uniform blade actuator system operable with one or more of the plurality of linkages to control a pitch of the first fan blade relative to a pitch of the second fan blade.

We claim: 
     
         1 . A gas turbine engine comprising:
 a turbomachine comprising a compressor section, a combustion section, and a turbine section arranged in serial flow order;   a fan defining a fan axis and comprising a plurality of fan blades rotatable about the fan axis; and   a pitch change mechanism operable with the plurality of fan blades, the pitch change mechanism comprising:
 a plurality of linkages, each linkage of the plurality of linkages coupled to a respective fan blade of the plurality of fan blades; and 
 a plurality of blade actuators, each blade actuator of the plurality of blade actuators configured as a variable length actuator for varying an effective length of a respective linkage of the plurality of linkages. 
   
     
     
         2 . The gas turbine engine of  claim 1 , wherein each blade actuator of the plurality of blade actuators is integrated into the respective linkage. 
     
     
         3 . The gas turbine engine of  claim 2 , wherein each blade actuator couples a first section of the respective linkage to a second section of the respective linkage. 
     
     
         4 . The gas turbine engine of  claim 3 , wherein a length of each blade actuator directly affects a spacing between the first and second sections of the respective linkage. 
     
     
         5 . The gas turbine engine of  claim 1 , wherein each blade actuator comprises a housing and a rod moveable relative to the housing. 
     
     
         6 . The gas turbine engine of  claim 5 , wherein the rod is movable relative to the housing through use of an electric motor, a hydraulic assembly, or a pneumatic assembly. 
     
     
         7 . The gas turbine engine of  claim 5 , wherein each blade actuator is movable between a retracted position and an extended position, wherein in the retracted position the rod is at least partially retracted within the housing, and wherein in the extended position the rod is at least partially extended from the housing. 
     
     
         8 . The gas turbine engine of  claim 7 , wherein each blade actuator defines a first overall length when in the retracted position and a second overall length when in the extended position, the second overall length being greater than the first overall length. 
     
     
         9 . The gas turbine engine of  claim 8 , wherein the second overall length is at least about 10% greater than the first overall length. 
     
     
         10 . The gas turbine engine of  claim 8 , wherein the second overall length is at least about 20% greater than the first overall length. 
     
     
         11 . The gas turbine engine of  claim 8 , wherein the second overall length is at least about 50% greater than the first overall length. 
     
     
         12 . The gas turbine engine of  claim 8 , wherein the second overall length is up to about 200% greater than the first overall length. 
     
     
         13 . The gas turbine engine of  claim 1 , wherein each blade actuator is operable to individually control a pitch of the respective fan blade. 
     
     
         14 . The gas turbine engine of  claim 1 , wherein the effective overall length of each linkage directly affects a pitch of the respective fan blade. 
     
     
         15 . A pitch change mechanism for a gas turbine engine having a turbomachine and a fan, the fan including a plurality of fan blades, the pitch change mechanism comprising:
 a plurality of linkages, each linkage of the plurality of linkages configured to be coupled to a respective fan blade of the plurality of fan blades; and   a plurality of blade actuators, each blade actuator of the plurality of blade actuators configured as a variable length actuator for varying an effective length of a respective linkage of the plurality of linkages.   
     
     
         16 . The pitch change mechanism of  claim 15 , wherein each blade actuator comprises a housing and a rod moveable relative to the housing. 
     
     
         17 . The pitch change mechanism of  claim 16 , wherein each blade actuator is movable between a retracted position where the rod is at least partially retracted within the housing and an extended position where the rod is at least partially extended from the housing. 
     
     
         18 . The pitch change mechanism of  claim 17 , wherein each blade actuator defines a first overall length when in the retracted position and a second overall length when in the extended position, the second overall length being greater than the first overall length. 
     
     
         19 . The pitch change mechanism of  claim 15 , wherein each blade actuator is integrated into the respective linkage and couples a first section of the respective linkage to a second section of the respective linkage. 
     
     
         20 . The pitch change mechanism of  claim 15 , wherein each blade actuator is operable to individually control a pitch of the respective fan blade by varying the effective length of the respective linkage.