Patent Publication Number: US-2013233997-A1

Title: Turbine engine case mount

Description:
BACKGROUND 
     The subject matter disclosed herein relates generally to an engine mounting configuration and, in particular, to an engine mounting configuration for mounting a turbofan gas turbine engine to an aircraft pylon. 
     A gas turbine engine may be mounted at various points on an aircraft such as a pylon integrated with an aircraft structure. An engine mounting configuration ensures the transmission of loads between the engine and the aircraft structure. The loads typically include the weight of the engine, its thrust, aerodynamic loads, maneuver loads, and rotary torque about the engine axis. The engine mounting configuration must also absorb the deformations to which the engine is subjected during different flight phases and the dimensional variations due to thermal expansion and retraction. 
     One conventional engine mounting configuration includes a pylon having a forward mount and an aft mount. The front fan case mount handles the vertical and side loads from the front of the engine. The rear mount handles vertical and side loads from the rear of the engine, engine torque, and thrust through a set of thrust links reaching from the rear mount forward to the intermediate case. 
     External components including mounts, electrical systems, lubrication systems, fuel systems, and the like all reside on the outside shell of the engine core. As engines are becoming small in core size, these components tend not to scale linearly, if at all, in size causing an issue for the proper attachment of the hardware to the smaller sized engine casings. The typical mounting systems include numerous poles and brackets, which extend into areas also needed for the additional hardware. A system that would reduce the size of the mounting system, and thus the time to attach the engine to an aircraft, would prove beneficial. 
     SUMMARY 
     In one embodiment, a mount for a turbine engine has a semi-circular yoke with a first leg and a second leg. The mount also has a stanchion with a cylindrical section attached to the yoke, and a conical section attached to the cylindrical section. A mounting bracket is attached to the conical section. 
     In another embodiment, a gas turbine engine mounting configuration has a pylon, and a turbine engine case mount attached to the pylon. The mount has a yoke having a first leg and a second leg, a support post attached to the yoke, and a mounting bracket attached to the support post. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a prior art turbofan gas turbine engine. 
         FIG. 2  is a perspective view of a turbofan gas turbine engine. 
         FIG. 3  is a cross-sectional view of a turbofan gas turbine engine. 
         FIG. 4  is a perspective view of an engine mount. 
         FIG. 5  is a perspective view of an engine mount attached to a pylon. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates a perspective view of gas turbofan engine  10  suspended from a mounting system that includes fan case or front mount  86 , rear mount  88 , and thrust links  90 . Turbofan engine  10  includes a core engine that includes low pressure compressor  16 , high pressure compressor  18 , and combustor  20 . Turbofan engine  10  also includes low pressure turbine  22  and high pressure turbine  24 . Fan section  26  is connected to low pressure compressor  16  either directly or through a gear train (not shown). The engine is mounted to an aircraft through front mount  86  and rear mount  88 , and thrust links  90  extend from rear mount  88  to intermediate case  36 . The arrangement with thrust links  90  is utilized to minimize the thrust induced bending of the engine core which would be caused if the thrust were reacted at the rear mount points shown in  FIG. 1  at the top of the turbine exhaust case. Bending of the engine core causes the clearances between the engine blade tips and the shrouding to increase causing a decrease in engine performance. External components (not illustrated) including additional mounts, electrical systems, lubrication systems, fuel systems, and the like all reside on the outside shell of the engine core. The thrust links  90  reduce the area available for positioning of the external components, causing an issue for the proper packaging of the hardware within the space between the engine cases and the nacelle core cowls. 
       FIG. 2  illustrates a perspective view of gas turbofan engine  10  suspended from an engine pylon  50 .  FIG. 3  illustrates a cross-sectional view of gas turbofan engine  10  with an engine nacelle assembly  14 . Turbofan engine  10  includes a core engine within nacelle  14  that includes low pressure compressor  16 , high pressure compressor  18 , and combustor  20 . Turbofan engine  10  also includes low pressure turbine  22  and high pressure turbine  24 . Fan section  26  is connected to low pressure compressor  16  either directly or through a gear train (not shown). 
     High pressure compressor  18  and high pressure turbine  24  are connected by a common shaft, while low pressure compressor  16  and low pressure turbine  22  are similarly connected by a second shaft. The shafts are co-axial about a central axis of turbofan engine  10 . Combustor  20  is arranged between high pressure compressor  18  and high pressure turbine  24 . Airflow enters fan  26  and nacelle  14  which at least partially surrounds the core engine. Fan section  26  communicates airflow into nacelle  14  to low pressure compressor  16 . Core airflow is compressed by low pressure compressor  16  and high pressure compressor  18 , and then is mixed with the fuel in combustor  20  where the fuel is ignited, and burned. The resultant combustor products and exhaust are expanded through high pressure turbine  24  and low pressure turbine  22 . Turbines  22  and  24  are rotationally coupled to compressors  16  and  18 , respectively to drive compressors  16  and  18  in response to the expansion of the combustion process. Low pressure turbine  22  also drives fan section  26 . A core engine exhaust exits turbine engine  10  through core nozzle  30  and tail cone  32  opposite fan section  26 . 
     Turbine engine  10  generally has case structures including fan case  34 , intermediate case  36 , high pressure compressor case  38 , combustor case  40 , low pressure turbine case  42 , and turbine exhaust case  44 . Fan section  26  includes fan rotor with a plurality of circumferentially spaced radially outwardly extending fan blades  46 . Fan blades  46  are surrounded by fan case  34 . The core engine case structures are secured to nacelle  14  via fan case  34 , which is connected to inlet case  35 , which includes a multiple of circumferentially spaced radially extending struts  48  which radially span the core engine case structure and fan case  34 . External components including electrical systems, lubrication systems, fuel systems, and the like (not illustrated) reside on the outside of the case structure and the inside of nacelle core cowls  31  of turbine engine  10 . 
     Turbine exhaust case  44  connects turbine engine  10  to an aircraft through an attachment to pylon  50 . The attachment is made by pin  52  secured to mount  54 . In the embodiment of  FIG. 2 , the end of pylon  50  that is opposite pin  52  and mount  54  is connected to low pressure compressor case  33  or intermediate case  36 . In  FIG. 3 , the end of pylon  50  that is opposite pin  52  and mount  54  is secured to fan case  34 . Mount  54  is also connected to engine pads on turbine exhaust case  44 . 
       FIG. 4  is a perspective view of mount  54 , illustrating first and second legs  60  and  62  of yoke  64 , stanchion  66 , and bracket  68 . Yoke  64  is illustrated as a semi-circular saddle that receives the generally circular turbine exhaust case  44  (see  FIGS. 1 and 2 ). Yoke  64  has two legs,  60  and  62 . Each leg  60  and  62  contains an aperture for fastener  70  for securing turbine exhaust case  44 . Fasteners  70  may contain a ball joint to equalize thrust loads (T 1  and T 2 ) and vertical or torque loads (V 1  and V 2 ). Fastener  70  on second leg  62  is secured with a radially free pin on the joints, while fastener  70  on first leg  60  contains a different attachment that carries side loads S. 
     As illustrated in  FIG. 5 , fasteners  70  may be bolts, with the Bolton leg  62  attached in such a way as to allow radial movement. Apertures  82  are circular holes on each leg  60  and  62 , and contain bearing  84 . This is opposed to the slot that receives a fastener illustrated in  FIG. 4 . 
     Stanchion  66  is centrally secured to yoke  64 . In the embodiment illustrated, stanchion is a vertical support post that has cylindrical section  72  attached to yoke  64 , and conical section  74  attached to cylindrical section  72 . Conical section  74  provides for a tapering of the cross-sectional area of stanchion  66 , while cylindrical section  72  maximizes the amount of contact with pylon  50 . Conical section  74  is also connected to smaller cylindrical section  76  that is attached to bracket  68 . Tapering of the cross-sectional area allows for a reduced area adjacent pylon  50  where space is limited, whereas cylindrical section  72  is at an area of turbofan engine  10  that has a greater area to receive components. 
     Bracket  68  is D-shaped, and contains an aperture therein for receiving pin  52 . The aperture may contain a spherical bearing  78 . This allows bracket  68  to spin about a vertical axis A-A normal to a central axis C-C of turbine engine  10 . In the embodiment illustrated and described, mount  54  allows for a determinate system having six degrees of freedom to compensate the various loads of turbine engine  10  with respect to pylon  50 . Mount  54  is free to rotate about pin  52 , thus allowing for T 1 =T 2 . Similarly, having only one leg to compensate for side loads S incorporates an allowance for thermal expansion and contraction of turbine exhaust case  44  during normal operation of turbofan engine  10 . Having the mount legs  60  and  62  reach down to the same plane as the engine centerline, engine core bending due to thrust is eliminated. 
     Mount  54  eliminates the need for multiple links and bracket systems that include thrust links, connection links, and various other components for mounting turbine engine  10 , as is the current state of the art illustrated in  FIG. 1 . The multiple components each address different loads. Mount  54  solves the multi-component issue by taking vertical, thrust, torque and side loads all within a single design piece. As illustrated in  FIG. 5 , this further simplifies mounting concerns as only a single pin  52  is needed to attach and remove mount  54  from pylon  50  of an aircraft. Pin  52  may be secured to pylon  50  with another fastener, such as nut  80 . The aft end of turbine engine  10  may be mounted or dismounted in much less time compared to other designs. Additionally, there may be weight savings on turbine engine  10  as fewer components are accomplishing the same function. The front end of pylon  50  may be attached utilizing a mounting arrangement  86  known in the art. The attachment of the front of pylon  50  may be to the fan case, intermediate case, or similar acceptable structural component of turbofan engine  10 . 
     Mount  54  is constructed from a high tensile, strong material such as steel or similar metal. Mount  54  may be machined from a solid block, or may be fabricated from several individual components secured together, such as by welding. 
     DISCUSSION OF POSSIBLE EMBODIMENTS 
     The following are non-exclusive descriptions of possible embodiments of the present invention. 
     A mount for a turbine engine has a semi-circular yoke with a first leg and a second leg. The mount also has a stanchion with a cylindrical section attached to the yoke, and a conical section attached to the cylindrical section. A mounting bracket is attached to the conical section. 
     The mount for the turbine engine of the preceding paragraph can optionally include, additionally and/or alternatively any, one or more of the following features, configurations and/or additional components: 
     the first leg and second leg may comprise apertures for receiving a first fastener and a second fastener, respectively; 
     the first leg and second leg may further comprise ball joints; 
     the first leg and the second leg may counteract vertical loads, torque and thrust loads; 
     the first leg may counteracts a side load; 
     the mounting bracket may comprise a spherical bearing; and/or 
     the apertures for the first fastener and the second fastener may be aligned about a diameter of a turbine engine case. 
     In another embodiment, a gas turbine engine mounting configuration has a pylon, and a turbine engine case mount attached to the pylon. The mount has a yoke having a first leg and a second leg, a support post attached to the yoke, and a mounting bracket attached to the support post. 
     The gas turbine engine mounting configuration of the preceding paragraph can optionally include, additionally and/or alternatively any, one or more of the following features, configurations and/or additional components: 
     the mount may attach to a turbine engine case; 
     the first leg may include a first attachment fastener aperture and the second leg may include a second attachment fastener aperture, the first attachment fastener aperture and the second attachment fastener aperture defined along an attachment fastener axis which extend radially inward to intersect the engine axis; 
     the first attachment aperture and the second attachment aperture may contain bearings; 
     the first leg and the second leg may counteract vertical loads, torque and thrust loads; 
     the first leg may also counteracts a side load; 
     the support post may be fixed about a vertical axis which intersects said engine axis; 
     the mount may comprise a spherical bearing; 
     the mount may be rotatable about a vertical axis which intersects said engine axis; 
     the pylon may attach to a fan case; and/or 
     the pylon may attach to an intermediate case of the gas turbine engine. 
     While the invention has been described with reference to an exemplary embodiment(s), it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment(s) disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.