Abstract:
An airfoil component includes an insert that has angled faces joined at an edge that provides an airfoil trailing edge. An outer CMC fiber layer overlaps the angled faces to provide a trailing edge portion of an airfoil.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Application No. 61/881,121, which was filed on Sep. 23, 2013 and is incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    This disclosure relates to a gas turbine engine, and, more particularly, to composite airfoil components, such as vanes or blades. 
         [0003]    Gas turbine engines typically include a compressor section, a combustor section and a turbine section. During operation, air is pressurized in the compressor section and is mixed with fuel and burned in the combustor section to generate hot combustion gases. The hot combustion gases are communicated through the turbine section, which extracts energy from the hot combustion gases to power the compressor section and other gas turbine engine loads. 
         [0004]    Both the compressor and turbine sections may include alternating series of rotating blades and stationary vanes that extend into the core flow path of the gas turbine engine. For example, in the turbine section, turbine blades rotate and extract energy from the hot combustion gases that are communicated along the core flow path of the gas turbine engine. The turbine vanes, which generally do not rotate, guide the airflow and prepare it for the next set of blades. 
         [0005]    The turbine section of the engine experiences high temperatures, which can limit the life of hot section components, such as vanes and blades. One type of turbine vane is constructed from a composite material, which is difficult to manufacture. 
         [0006]    Aerodynamic performance is dependent on a sharp airfoil trailing edge radius. Typically, ceramic composite materials, such as ceramic matrix composites (CMC), are too stiff to wrap around the trailing edge radius without breaking fibers which damages the material and creates a rough surface finish and thicker trailing edge. So, instead the free ends of the layers are joined to one another at the trailing edge. Machining the CMC to the desired radius can also be extremely costly and time-consuming due to the hardness of the CMC material. 
       SUMMARY 
       [0007]    In one exemplary embodiment, an airfoil component includes an insert that has angled faces joined at an edge that provides an airfoil trailing edge. An outer CMC fiber layer overlaps the angled faces to provide a trailing edge portion of an airfoil. 
         [0008]    In a further embodiment of the above, the insert is ceramic. 
         [0009]    In a further embodiment of any of the above, the outer CMC layer provides a pressure side and a suction side. 
         [0010]    In a further embodiment of any of the above, an inner CMC fiber layer provides an internal cavity to the airfoil. 
         [0011]    In a further embodiment of any of the above, the inner CMC fiber layer adjoins and provides backing to an inner face of the insert that joins the angled faces. 
         [0012]    In a further embodiment of any of the above, voids are provided between the inner CMC fiber layer and the insert. The voids are filled with a ceramic-based resin. 
         [0013]    In a further embodiment of any of the above, the inner CMC fiber layer includes multiple plies. 
         [0014]    In a further embodiment of any of the above, the outer CMC fiber layer includes multiple plies. 
         [0015]    In a further embodiment of any of the above, the outer CMC fiber layer wraps about the edge such that the insert does not provide an exterior airfoil surface. 
         [0016]    In a further embodiment of any of the above, the outer CMC fiber layer overlaps the insert and provides a free end that is short of and spaced from the edge such that a portion of the insert provides the exterior airfoil surface. 
         [0017]    In another exemplary embodiment, an airfoil component includes an inner CMC fiber layer that provides an internal cavity to the airfoil. An insert that has angled faces is joined at an edge that provides an airfoil trailing edge. The inner CMC fiber layer adjoins and provides backing to an inner face of the insert that joins the angled faces. An outer CMC fiber layer overlaps the angled faces to provide a trailing edge portion of an airfoil. The outer CMC fiber layer includes multiple plies and provides a pressure side and a suction side. 
         [0018]    In a further embodiment of any of the above, the insert in ceramic. 
         [0019]    In a further embodiment of any of the above, voids are provided between the inner CMC fiber layer and the insert. The voids are filled with a ceramic-based resin. 
         [0020]    In a further embodiment of any of the above, the outer CMC fiber layer wraps about the edge such that the insert does not provide an exterior airfoil surface. 
         [0021]    In a further embodiment of any of the above, the outer CMC fiber layer overlaps the insert and provides a free end that is short of and spaced from the edge such that a portion of the insert provides the exterior airfoil surface. 
         [0022]    In a further embodiment of any of the above, an airfoil component includes the steps of overlapping a CMC fiber layer over angled faces of an insert to provide to trailing edge portion of an exterior airfoil surface. 
         [0023]    In a further embodiment of any of the above, the insert is at least one of a monolithic ceramic and chopped ceramic fibers with resin. 
         [0024]    In a further embodiment of any of the above, an airfoil component includes the steps of machining an edge of the ceramic insert joining the angled faces. 
         [0025]    In a further embodiment of any of the above, the outer CMC fiber layer wraps about the edge such that the insert does not provide an exterior airfoil surface. 
         [0026]    In a further embodiment of any of the above, the outer CMC fiber layer overlaps the insert and provides a free end that is short of and spaced from the edge such that a portion of the insert provides the exterior airfoil surface. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0027]    The disclosure can be further understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: 
           [0028]      FIG. 1  schematically illustrates vane. 
           [0029]      FIG. 2  is a cross-sectional view through the vane shown in  FIG. 1  taken along line  2 - 2 . 
           [0030]      FIG. 3  is an enlarged cross-sectional view of a trailing edge portion depicted in  FIG. 2 . 
           [0031]      FIG. 4  is another example trailing edge portion cross-section. 
       
    
    
       [0032]    The embodiments, examples and alternatives of the preceding paragraphs, the claims, or the following description and drawings, including any of their various aspects or respective individual features, may be taken independently or in any combination. Features described in connection with one embodiment are applicable to all embodiments, unless such features are incompatible. 
       DETAILED DESCRIPTION 
       [0033]    An airfoil component  10 , such as a vane, is shown in  FIG. 1 . The component  10  includes an airfoil  14  extending in a radial direction from a platform  12 . The airfoil  14  includes an exterior airfoil surface  24  having pressure and suction sides  20 ,  22  that are adjoin one another at leading and trailing edges  16 ,  18 . It is desirable for the trailing edge  18  to have a relatively sharp radius for desired aerodynamic performance. 
         [0034]    In the example of the airfoil component  10  being a vane, it may be desirable to provide a cavity  26  the radial length of the component to permit other components  28 , such as wires and/or air or lubrication conduits, to pass through the cavity  26  from outside the engine to an interior of the engine. The cavity may be a single, large cavity as show at  26  in  FIG. 1 , or the cavity  26  may be bifurcated as shown in  FIG. 2 . It should be understood that the airfoil component may also be a blade. 
         [0035]    An example cross-section of the airfoil  14  is shown in  FIG. 2 . In the example, the cavity  26  is provided by a first and second cavities  30 ,  32 , respectively provided by first and second wrapped inner CMC fiber layers  34 ,  36 . The inner CMC fiber layers  34 ,  36  may each be provided by multiple plies. 
         [0036]    A ceramic insert  38  is provided at the trailing edge portion of the airfoil  14  to provide the trailing edge  18 . In one example, the ceramic insert is provided by a monolithic ceramic or chopped CMC fibers with resin. 
         [0037]    Referring to  FIG. 3 , an example trailing edge configuration is shown. The ceramic insert  38  includes angled faces  40  extending from an inner face  42  toward one another to an edge  58 , which provides the trailing edge  18 . In this example, the ceramic insert provides a generally triangular shape when viewed in cross-section as shown. The edge  58  can be molded to provide the desired radius or machined. 
         [0038]    In the example, the inner CMC fiber layer  36  is adjacent to and backs the inner face  42  of the insert  38  to provide stability. Due to the difficulty of providing sharp edges with the inner CMC fiber layer  36 , voids  44  may result between the inner CMC fiber layer  36  and the inner face  42 , which can be filled with a filler. The filler may be constructed from any suitable material, such as stacked fibers, unidirectional material, laid up fabric, chopped fibers, a monolithic structure, resin or any other suitable material in configuration that it conforms to the voids  44 . 
         [0039]    A first layer  46 , which may be provided by multiple plys, is laid over the angled faces  40 . A free end  50  of the first layer  46  is arranged short of or spaced from the edge  58 , such that at least a portion of the angled faces  40  are exposed to provide a portion of the exterior airfoil surface  24 . Additional layers  48  may be laid over the first layer  46 . In this example a second layer  48  includes a second free ends  52  that are also short of the edge  58 . The second free ends  52  may be short of the first free ends  50  to provide additional taper at the trailing edge portion. 
         [0040]    Referring to  FIG. 4 , another example trailing edge configuration is shown. An example, the first layer  146  may be wrapped about the edge  58  so that the insert  38  is not exposed and does not provide the exterior airfoil surface  24 . 
         [0041]    It should also be understood that although a particular component arrangement is disclosed in the illustrated embodiment, other arrangements will benefit herefrom. Although particular step sequences are shown, described, and claimed, it should be understood that steps may be performed in any order, separated or combined unless otherwise indicated and will still benefit from the present invention. 
         [0042]    Although the different examples have specific components shown in the illustrations, embodiments of this invention are not limited to those particular combinations. It is possible to use some of the components or features from one of the examples in combination with features or components from another one of the examples. 
         [0043]    Although example embodiments have been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of the claims. For that and other reasons, the following claims should be studied to determine their true scope and content.