Patent Publication Number: US-2019195379-A1

Title: Additively manufactured integrated valve and actuator for a gas turbine engine

Description:
TECHNICAL FIELD 
     The present disclosure relates generally to valve and actuator assemblies for a gas turbine engine, and more specifically to an additively manufactured valve and actuator assembly having a single integrated housing body. 
     BACKGROUND 
     Gas turbine engines, such as those utilized in commercial and military aircraft, include a compressor section that compresses air, a combustor section in which the compressed air is mixed with a fuel and ignited, and a turbine section across which the resultant combustion products are expanded. The expansion of the combustion products drives the turbine section to rotate. As the turbine section is connected to the compressor section via a shaft, the rotation of the turbine section further drives the compressor section to rotate. In some examples, a fan is also connected to the shaft and is driven to rotate via rotation of the turbine as well. 
     Gas turbine engines typically include one or more engine air provision and regulation components, such as a regulating valve. The provision and regulation components are utilized to regulate the flow of engine air between various portions of the engine. 
     SUMMARY OF THE INVENTION 
     In one exemplary embodiment an engine air valve assembly for a gas turbine engine includes a butterfly valve including a translation shaft, a fueldraulic actuator including a piston, the piston being mechanically linked to the translation shaft by an axial to rotational conversion linkage, and a regulating valve housing containing the butterfly valve and the fueldraulic actuator, the regulating valve housing comprising an actuator housing portion and a valve housing portion joined via a joint section, the regulating valve housing being a single integral piece. 
     An exemplary method for assembling an engine air valve includes additively manufacturing a regulating valve housing comprising an actuator housing portion and a valve housing portion joined via a joint section as a single integral piece, and inserting a butterfly valve in the valve housing portion, a fueldraulic actuator piston in the actuator portion, and a translation shaft connecting the butterfly valve to the fueldraulic actuator piston. 
     These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a high level schematic view of an gas turbine engine. 
         FIG. 2  schematically illustrates an isometric view of an additively manufactured fueldraulic valve assembly. 
         FIG. 3  schematically illustrates a cross sectional view of the fueldraulic valve assembly of  FIG. 2 . 
         FIG. 4  schematically illustrates an end view of the fueldraulic valve assembly of  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION OF AN EMBODIMENT 
       FIG. 1  schematically illustrates a gas turbine engine  20 . The gas turbine engine  20  is disclosed herein as a two-spool turbofan that generally incorporates a fan section  22 , a compressor section  24 , a combustor section  26  and a turbine section  28 . Alternative engines might include an augmentor section (not shown) among other systems or features. The fan section  22  drives air along a bypass flow path B in a bypass duct defined within a nacelle  15 , and also drives air along a core flow path C for compression and communication into the combustor section  26  then expansion through the turbine section  28 . Although depicted as a two-spool turbofan gas turbine engine in the disclosed non-limiting embodiment, it should be understood that the concepts described herein are not limited to use with two-spool turbofans as the teachings may be applied to other types of turbine engines including three-spool architectures. 
     The exemplary engine  20  generally includes a low speed spool  30  and a high speed spool  32  mounted for rotation about an engine central longitudinal axis A relative to an engine static structure  36  via several bearing systems  38 . It should be understood that various bearing systems  38  at various locations may alternatively or additionally be provided, and the location of bearing systems  38  may be varied as appropriate to the application. 
     The low speed spool  30  generally includes an inner shaft  40  that interconnects a fan  42 , a first (or low) pressure compressor  44  and a first (or low) pressure turbine  46 . The inner shaft  40  is connected to the fan  42  through a speed change mechanism, which in exemplary gas turbine engine  20  is illustrated as a geared architecture  48  to drive the fan  42  at a lower speed than the low speed spool  30 . The high speed spool  32  includes an outer shaft  50  that interconnects a second (or high) pressure compressor  52  and a second (or high) pressure turbine  54 . A combustor  56  is arranged in exemplary gas turbine  20  between the high pressure compressor  52  and the high pressure turbine  54 . A mid-turbine frame  57  of the engine static structure  36  is arranged generally between the high pressure turbine  54  and the low pressure turbine  46 . The mid-turbine frame  57  further supports bearing systems  38  in the turbine section  28 . The inner shaft  40  and the outer shaft  50  are concentric and rotate via bearing systems  38  about the engine central longitudinal axis A which is collinear with their longitudinal axes. 
     The core airflow is compressed by the low pressure compressor  44  then the high pressure compressor  52 , mixed and burned with fuel in the combustor  56 , then expanded over the high pressure turbine  54  and low pressure turbine  46 . The mid-turbine frame  57  includes airfoils  59  which are in the core airflow path C. The turbines  46 ,  54  rotationally drive the respective low speed spool  30  and high speed spool  32  in response to the expansion. It will be appreciated that each of the positions of the fan section  22 , compressor section  24 , combustor section  26 , turbine section  28 , and fan drive gear system  48  may be varied. For example, gear system  48  may be located aft of combustor section  26  or even aft of turbine section  28 , and fan section  22  may be positioned forward or aft of the location of gear system  48 . 
     The engine  20  in one example is a high-bypass geared aircraft engine. In a further example, the engine  20  bypass ratio is greater than about six (6), with an example embodiment being greater than about ten (10), the geared architecture  48  is an epicyclic gear train, such as a planetary gear system or other gear system, with a gear reduction ratio of greater than about 2.3 and the low pressure turbine  46  has a pressure ratio that is greater than about five. In one disclosed embodiment, the engine  20  bypass ratio is greater than about ten (10:1), the fan diameter is significantly larger than that of the low pressure compressor  44 , and the low pressure turbine  46  has a pressure ratio that is greater than about five 5:1. Low pressure turbine  46  pressure ratio is pressure measured prior to inlet of low pressure turbine  46  as related to the pressure at the outlet of the low pressure turbine  46  prior to an exhaust nozzle. The geared architecture  48  may be an epicycle gear train, such as a planetary gear system or other gear system, with a gear reduction ratio of greater than about 2.3:1. It should be understood, however, that the above parameters are only exemplary of one embodiment of a geared architecture engine and that the present invention is applicable to other gas turbine engines including direct drive turbofans. 
     A significant amount of thrust is provided by the bypass flow B due to the high bypass ratio. The fan section  22  of the engine  20  is designed for a particular flight condition—typically cruise at about 0.8 Mach and about 35,000 feet (10,668 meters). The flight condition of 0.8 Mach and 35,000 ft (10,668 meters), with the engine at its best fuel consumption—also known as “bucket cruise Thrust Specific Fuel Consumption (‘TSFC’)”—is the industry standard parameter of lbm of fuel being burned divided by lbf of thrust the engine produces at that minimum point. “Low fan pressure ratio” is the pressure ratio across the fan blade alone, without a Fan Exit Guide Vane (“FEGV”) system. The low fan pressure ratio as disclosed herein according to one non-limiting embodiment is less than about 1.45. “Low corrected fan tip speed” is the actual fan tip speed in ft/sec divided by an industry standard temperature correction of [(Tram ° R)/(518.7° R)]̂ 0.5 . The “Low corrected fan tip speed” as disclosed herein according to one non-limiting embodiment is less than about 1150 ft/second (350.5 meters/second). 
     Existing gas turbine engines, such as turbofan engines, utilize internal engine components to direct flows of engine air from one portion of the engine to another portion of the engine. One component used to control and direct flows of engine air is a fueldraulic valve. Existing fueldraulic valves utilize a two part construction including a fireproof valve housing connected to an actuator housing via fasteners joining a pair of corresponding joint flanges. The fireproof valve housing is typically constructed of steel, or another high melting point material in order to facilitate the high temperature engine air passing through the valve housing. A valve is housed in the valve housing and controls a flow of engine air through the valve housing. 
     In contrast, the actuator housing is not required to accommodate high temperature air and is constructed of aluminum in order to reduce the overall weight of the component. A shaft extends from the actuator housing into the valve housing, allowing a piston shaft within the actuator to control a position of the valve, and thereby control the magnitude of engine air allowed to pass through the valve. 
     With continued reference to  FIG. 1 ,  FIG. 2  schematically illustrates an isometric view of a fueldraulic valve assembly  100  including a combined valve housing  110  and actuator housing  120 . The valve housing  110  and the actuator housing  120  are joined via a joint section  130  including a pass-through passage  134  (illustrated in  FIG. 3 ) that allows a translation shaft  132  (illustrated in  FIG. 3 ) to connect a fueldraulicly actuated piston  150  (illustrated in  FIG. 4 ) in the actuator housing  120  to a butterfly valve  112  (illustrated in  FIG. 4 ) disposed within the valve housing  110 . The valve housing  110 , the joint section  130 , and the actuator housing  120  are a single integral body, constructed via an additive manufacturing process. As used herein, an integral body refers to a body constructed as a single piece, rather than as multiple pieces joined together. 
     In some examples, the additive manufacturing process can create the singular body using a single uniform material such as titanium, or a titanium alloy. In alternative examples, the singular body can be created of a composition of multiple materials including titanium. In further examples, the specific material from which the entire body is constructed is Ti-64. Construction of either, or both, of the component parts of the previous examples using titanium alloys and a casting or milling process is cost prohibitive, especially when design changes are anticipated, for small production quantities, and/or for demonstration hardware. Further, even if the high cost of cast or milled titanium were warranted, the process of casting and milling the component parts out of titanium results in an excessively lengthy manufacturing process. 
     By integrating the valve housing  110  and the actuator housing  120  into a single body, and using additively manufactured construction with a titanium material, the weight of the valve assembly  100  is reduced relative to previous distinct bodies for the valve housing  110  and the actuator housing  120 . By way of example, a single body titanium based valve assembly  100  can weigh in the range of 3.05-2.49 lbs. In some practical examples, the single body titanium assembly can weigh in the range of 2.91-2.63 lbs. In yet further examples, such as the example where the valve assembly  100  is constructed of Ti-64, the valve assembly  100  can weigh approximately 2.77 lbs. 
     With continued reference to  FIGS. 1 and 2 , and with like numerals indicating like elements,  FIG. 3  schematically illustrates a cross sectional view of the fueldraulic valve assembly  100  of  FIG. 2 . The fueldraulic valve assembly  100  includes connections  122  to a fuel source, with the connections  122  being joined via a piston shaft chamber  124 . The piston shaft chamber  124  houses a piston (omitted for illustrative clarity) that is shifted along an axis B defined by the piston shaft chamber  124  utilizing pressurized fuel contained within the piston shaft chamber  124 . The piston  150  is connected to a butterfly valve  112  disposed in the valve housing  110  by a translation shaft  132 . The piston  150  is shifted axially by controlling the relative pressure of the fuel at each end of the piston shaft chamber  124  in a conventional hydraulic manner, with the fuel operating as the hydraulic fluid. The translation shaft  132  converts axial movement of the piston shaft into rotational movement of the butterfly valve  112 . 
     The valve housing  110  includes a first opening  114  and a second opening  116  joined by an engine air flowpath  118 . In order to prevent pressurized fuel from traveling from the piston shaft chamber  124  to the engine air flowpath  118 , a seal  136  is disposed within the through passage  134 , and seals against the translation shaft  132 . In some examples the seal is an O-ring type seal manufactured from fluorocarbon. In alternative examples, fluorosilicone seal types could be utilized in place of the O-ring type seal. 
     A further benefit of constructing the assembly  100  via the additive manufacturing process is the integrated inclusion of snaking plumbing lines  140 ,  142  into the valve assembly  100 . The actuator housing  120  further includes multiple integral plumbing lines  140 ,  142 . The integral plumbing lines  140 ,  142  allow for a controller to adjust the pressure on each axial end of the piston shaft chamber  124  by allowing the amount of fuel at each end of the piston shaft chamber  124  to be controlled and adjusted. Existing systems, utilizing cast or milled construction techniques, provide for plumbing lines by incorporating plumbing stubs, and drilling into the finished part at the stubs during a post manufacturing procedure. Plumbing lines are then connected to the stubs and allow for the desired fluid transfer. 
     In contrast to existing systems, the additively manufactured assembly  100  manufactures the plumbing lines  140 ,  142  integral to the actuator housing  120  and from the same material as the actuator housing  120  during the additive manufacturing process. By incorporating the plumbing lines  140 ,  142  into the housing itself, the weight of the valve assembly  100  is further reduced, and complexity of manufacturing is reduced. 
     With continued reference to  FIGS. 1-3 ,  FIG. 4  schematically illustrates an end view of the fueldraulic valve assembly  100  of  FIG. 2 . The illustration of  FIG. 4  shows the butterfly valve  112  disposed within the engine air flowpath  118 . In one example, the butterfly valve is a three inch diameter butterfly valve. The butterfly valve  112  is connected to the translation shaft  132 , which is in turn connected to a piston  150  via an axial to rotational movement joint  152 . As the piston  150  shifts along the axis defined by the piston shaft chamber  124 , the axial to rotational movement joint  152  causes the translation shaft  132  to rotate about the axis of the translation shaft  132 . Since the butterfly valve  112  is fixedly connected to the translation shaft  132 , the rotation of the translation shaft  132  causes an equivalent rotation in the butterfly valve  112 . 
     It should be appreciated that the rotational position of the translation shaft  132 , and of the butterfly valve  112 , can be controlled via a standard controller, a dedicated controller, or any other known control system according to known hydraulic piston positioning techniques. 
     It is further understood that any of the above described concepts can be used alone or in combination with any or all of the other above described concepts. Although an embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.