Abstract:
A component blending tool for forming a pre-determined blended area into a component utilizes a belt having a material removing surface that is contoured to mimic a predetermined depth ratio of the blended area. The tool has an interchangeable shoe that contours the belt and forces the belt upon the component until the pre-determined blended area is

Description:
[0001]    This application claims priority to U.S. Patent Appln. No. 61/907,667 filed Nov. 22, 2013. 
     
    
     BACKGROUND 
       [0002]    The present disclosure relates generally to a component blending tool and more particularly, to a component blending tool having an abrasive belt for creating a blend area in a component. 
         [0003]    Gas turbine engines, such as those that power modern commercial and military aircraft, include a compressor section to pressurize a supply of air, a combustor section to burn a hydrocarbon fuel in the presence of the pressurized air, and a turbine section to extract energy from the resultant combustion gases and generate thrust. Such engines may also employ a geared architecture that connects a fan section, forward of the compressor section to the turbine section. 
         [0004]    Components of assemblies may include imperfections, such as nicks, dents, scratches, etc.. In high-performance assemblies, such as gas turbine engines, imperfections can reduce strength or fatigue life, especially in components that rotate during operation. Component stresses are increased adjacent to imperfections. The increased stress originating at an unrepaired imperfection can become an initiation site for a crack that can propagate until structural failure occurs. Relatively small imperfections, such as imperfections less than 0.010 inches (0.254 mm) deep, are often blended away from the component as oppose to costly scrapping of the component. 
         [0005]    Blending away an imperfection involves removing material from an area of the component to eliminate the imperfection. The area of removed material has a width and a depth characterized as a depth ratio. High-performance assemblies may require relatively high depth ratios, greater than 100 to 1 to minimize the abruptness of surface changes due to blending. Such imperfections may also be located on surfaces that are contoured, i.e. not planar, making the blending operation at high depth ratios that much more difficult and expensive to verify. 
       SUMMARY 
       [0006]    A component blending tool for blending a component according to one non-limiting embodiment of the present disclosure includes a shoe having a contour that corresponds to a blend ratio, and a belt having a first surface in slideable contact with the contour and a material removing surface such that said material removing surface is substantially the same as the blend ratio. 
         [0007]    In the alternative or additionally thereto, in the foregoing embodiment, the shoe is at least in part made of carbide. 
         [0008]    In the alternative or additionally thereto, in the foregoing embodiment, the tool has a graphite tape secured to the shoe and in sliding contact with the belt. 
         [0009]    In the alternative or additionally thereto, in the foregoing embodiment, the tool has first and an opposite second end of the shoe, a first transitioning pulley in receipt of the belt at the first end, and a second transitioning pulley in receipt of the belt at the second end. 
         [0010]    In the alternative or additionally thereto, in the foregoing embodiment, the tool has a drive pulley that drives the belt, a tension pulley that maintains belt tension, and a transitioning pulley that is orientated between the belt and the shoe. 
         [0011]    In the alternative or additionally thereto, in the foregoing embodiment, the tool has an engagement device for releasable engagement to the component, a first rail attached to the engagement device, and a carriage having the drive pulley, the tension pulley, the shoe and the transitioning pulley constructed and arranged to move along the first rail. 
         [0012]    In the alternative or additionally thereto, in the foregoing embodiment, the tool has a second rail being parallel to the first rail and attached to the engagement device, and first and second rollers of the carriage constructed and arranged to roll upon the respective first and second rails for guiding movement of the carriage across the component. 
         [0013]    In the alternative or additionally thereto, in the foregoing embodiment, the engagement device is a clamp structure for generally positioning the first rail through a bore defined by the face, and wherein the contour is substantially cylindrical having a radius less than a radius of the face. 
         [0014]    In the alternative or additionally thereto, in the foregoing embodiment, the tool has a frame positioned above the face, a resilient member engaged to the frame and the shoe, and an adjustment mechanism for moving the shoe toward the face against a biasing force of the resilient member. 
         [0015]    In the alternative or additionally thereto, in the foregoing embodiment, the tool has a car engaged to the resilient member and wherein the resilient member spans between the car and the frame and the shoe is removably attached to the car; a drive pulley engaged rotatably to the frame; a tension pulley engaged to the car; and at least one transitioning pulley engaged adjustably to the car with respect to the shoe. 
         [0016]    In the alternative or additionally thereto, in the foregoing embodiment, the tool has a base plate engaged to the shoe and detachably engaged to the car; first and second transitioning pulleys of the at least one transitioning pulley engaged rotatably to the base plate; and wherein the shoe spans longitudinally between the first and second transitioning pulleys. 
         [0017]    In the alternative or additionally thereto, in the foregoing embodiment, the adjustment mechanism is pivotally connected to the frame. 
         [0018]    In the alternative or additionally thereto, in the foregoing embodiment, the engagement device has a suction cup for securing the first rail to the component, and wherein the contour is substantially flat. 
         [0019]    In the alternative or additionally thereto, in the foregoing embodiment, a weight of the carriage biases the shoe against the face. 
         [0020]    In the alternative or additionally thereto, in the foregoing embodiment, the predetermined depth ratio is a ratio of a diameter of the blended area to a depth of the blended area and wherein the predetermined depth ratio is greater that about 100 to 1. 
         [0021]    In the alternative or additionally thereto, in the foregoing embodiment, a depth of the blended area is less than about 0.005 inches (0.127 millimeters) greater than a depth of an imperfection in the component that is removed when providing the blended area. 
         [0022]    A component according to another non-limiting embodiment of the present disclosure includes a face; a blended area formed into the face by a belt of a component blending tool; and, wherein the belt adjacent to the face has a contour that mimics a predetermined depth ratio of the blended area. 
         [0023]    A method of removing an imperfection from a face of a component according to another non-limiting embodiment of the present disclosure includes the steps of determining a desired depth ratio; choosing a shoe of the component blending tool that corresponds with the depth ratio; mounting the shoe to a car of the component blending tool; and driving a belt across the shoe and against the face to remove material from the component until the desired depth ratio is reached. 
         [0024]    In a further embodiment of the foregoing embodiment, the method has the further step of moving the belt across the face in a direction that is substantially normal to the direction of belt movement across the shoe. 
         [0025]    In the alternative or additionally thereto, in the foregoing embodiment, the method has the further step of moving the belt across the face in multiple passes wherein each pass removes a depth that is less than the size of abrasive particles secured to the belt. 
         [0026]    The foregoing features and elements may be combined in various combinations without exclusivity, unless expressly indicated otherwise. These features and elements as well as the operation thereof will become more apparent in light of the following description and the accompanying drawings. It should be understood, however, the following description and drawings are intended to be exemplary in nature and non-limiting. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0027]    Various features will become apparent to those skilled in the art from the following detailed description of the disclosed non-limiting embodiments. The drawings that accompany the detailed description can be briefly described as follows: 
           [0028]      FIG. 1  is a schematic cross-section of a gas turbine engine; 
           [0029]      FIG. 2  is a perspective view of a component being a rotor; 
           [0030]      FIG. 3  is a plan view of a portion of a face of the component; 
           [0031]      FIG. 4   a  is a partial cross section of the component illustrating an imperfection; 
           [0032]      FIG. 4   b  is a partial cross section of the component taken along line  4   b - 4   b  of  FIG. 3  and similar to  FIG. 4   a  except with the imperfection removed; 
           [0033]      FIG. 5  is a front perspective view of a component blending tool according to one non-limiting embodiment; 
           [0034]      FIG. 6  is a perspective view of the component blending tool with sections removed to show detail; 
           [0035]      FIG. 7  is a perspective side view of a carriage of the component blending tool with elements removed to show detail; 
           [0036]      FIG. 8  is a perspective view of a shoe of the component blending tool; 
           [0037]      FIG. 9  is a front plan view of a shoe assembly with a belt mounted thereon; 
           [0038]      FIG. 10  is a side view of the carriage with components removed to show detail; 
           [0039]      FIG. 11  is a partial cross section of the belt and component; and 
           [0040]      FIG. 12  is a bottom perspective view of a second example of a component blending tool used to create a three dimensional blend (i.e. spherical). 
       
    
    
     DETAILED DESCRIPTION 
       [0041]    Referring to  FIG. 1 , a turbomachine, such as a gas turbine engine  20 , is circumferentially disposed about an axis A. The gas turbine engine  20  includes a fan  22 , a low pressure compressor  24 , a high pressure compressor  26 , a combustor  28 , a high pressure turbine  30  and a low pressure turbine  32 . Other examples of turbomachines may include more or fewer components or assemblies. Although depicted as a turbofan in the disclosed non-limiting embodiment, it should be understood that the concepts described herein are not limited to use with turbofans as the teachings may be applied to other types of turbine engine architecture such as turbojets, turboshafts, and three-spool (plus fan) turbofans with an intermediate spool. 
         [0042]    During operation, air is compressed in the low pressure compressor  24  and the high pressure compressor  26 . The compressed air is then mixed with fuel and burned in the combustor  28 . The products of combustion are expanded across the high pressure turbine  30  and the low pressure turbine  32  thereby driving the fan  22 . 
         [0043]    The low and high pressure compressors have respective rotors  34 ,  36 . Likewise, the high and low pressure turbines have respective rotors  38 ,  40 . Each of the rotors  34 ,  36 ,  38 ,  40  include alternating rows of rotatable blades and static stators or vanes. In other aspects, not depicted in  FIG. 1 , mechanisms are used to create alternating rotating and counter-rotating rotors instead of rotatable blades and static vanes. The turbine rotors  38 ,  40  rotate in response to the air expansion to rotatably drive rotors  28 ,  30 . The high pressure turbine rotor  38  is coupled to the high pressure compressor rotor  36  via a spool  42 , and the low pressure turbine rotor  40  is coupled to the low pressure compressor rotor  34  via a spool  44 . The low spool  44  drives the fan  22  directly or through a geared architecture to drive the fan  22  at a lower speed than the low spool  44 . An exemplary reduction transmission is an epicyclic transmission, namely a planetary or star gear system. 
         [0044]    Referring to  FIGS. 2 to 4   b , the rotor  38  includes a cylindrical face  46  that defines a rotor bore  48  centered to axis A. In the face  46  may be a blended area  50  created when removing an imperfection  52 , such as a nick, crack, scratch, etc.. The blended area  50  may extend the entire length L of the bore  48 . In this example, the blended area  50  also has a 200 to 1 depth ratio. That is, the general width W of the blended area  50  is about 200 times greater than the depth D of the blended area  50 . In another example, the width W of the blended area  50  is about 100 times greater that the depth D of the blended area  50 . It should also be understood that the depth ratio may be considered a “blend ratio” is some instances. 
         [0045]    As one example, the blended area  50  illustrated may be limited to a two dimensional curved profile. That is, the curvature shown is a cross section profile where the cross section lies along an imaginary plane of the Y and Z Cartesian coordinates (see  FIG. 2 ). Therefore, the imaginary plane is normal to the X-axis or axis A. Because the blended area  50  may extend along the entire length L of bore  48  there may be no curved profile in, for instance, a cross section that lies along an imaginary plane containing the Z and X axis where axis A is linear. 
         [0046]    The depth D of the blended area  50  relative to the original face  46  is determined based on the depth of the imperfection  52  removed by the blended area  50 . In some examples, the depth D of the blended area  50  is less than about 0.005 inches (0.127 millimeters) deeper than the imperfection depth D′ (see  FIG. 4   a ) that represents the greatest depth of the imperfection  52 . In one specific example, the depth D of the blended area  50  is about 0.002 inches (0.0508 millimeters) deeper than the imperfection depth D′. 
         [0047]    Referring to  FIGS. 5 through 7 , a component blending tool  54  used to create the blended area  50  has a static structure  56  and a moving carriage  58 . The static structure  56  has an engagement device  60  that may include a plurality of releasable fasteners or clamps that secure to the component or rotor  38 . Orientation of the engagement device  60  is dictated by the surrounding structure of the component that carries the face  46  to be blended. As illustrated in one example, the static structure  56  generally resides within or extends through the bore  48  of the rotor  38 . Two guide rails  62  of the static structure  56  extend through the bore  48  and are orientated about parallel to the axis A and are spaced from one another such that the blended area  50  is centered below, and co-extends longitudinally to, the two rails  62 . 
         [0048]    The carriage  58 , as illustrated, has two pairs of rollers  64  that rest upon and ride along the respective rails  62 , a frame  66  that rotatably supports the rollers  64 , a car  68  engaged to the frame  66  by two resilient members  70  (e.g. leaf springs) and a shoe assembly  72  detachably engaged to the car  68  (also see  FIG. 7 ). An abrasive serpentine belt  74  of the carriage  58  rides across the shoe assembly  72  and is driven by a drive pulley  76  and motor  78  secured to the frame  66 . A tension pulley  80  and three guide pulleys  82  are rotatably mounted to the car  68  for maintaining a tension upon the belt  74 ; taking up belt slack in a dense configuration that allows entry of the carriage  58  into the relatively small component bore  48 ; and, for guiding the belt smoothly during belt oscillation. The serpentine belt  74  is continuous in the sense that it forms a continuous loop. However, such continuity may be established through splicing of a strap-like abrasive material thereby forming the continuous belt. 
         [0049]    Referring to  FIGS. 7 through 9 , the shoe assembly  72  includes a base plate  84  engaged detachably to the car  68 , a shoe  86  engaged to the base plate  84 , and two transitioning pulleys  90  mounted rotatably to the base plate  84  and at respective longitudinal ends  92 ,  94  of the shoe  86  (i.e. belt entry and exit points of the shoe). The belt  74  carries a material removing surface  88  that faces outward from the shoe as the belt is driven continuously across the shoe from the first end  92  to the second end  94  (i.e. for example respective entry and exit points). A substantially cylindrical contour  95  of the shoe  86  (and taking in consideration the thickness T of the belt  74 ), forms the substantially cylindrical contour  96  of the material removing surface  88 . Notably, the material removing surface contour  96  is the same as the desired contour of the blended area  50 . More specifically, a ratio of a width W′ of the material removing surface  88  to a depth D′ of the material removing surface  88  at the shoe  86  is about 200 to 1. The material removing surface contour  96  thus mimics a desired contour of the blended area  50 . The depth D′ can thus be represented as a portion of the overall radius R of the cylindrical contour  96  that is taken at mid-span or mid-point between the entry and exit points  92 ,  94  (see  FIG. 9 ). In the present example, the radius R is substantially constant throughout the length of the shoe; however, it is understood that other non-limiting embodiments may include curving profiles that do not have a constant radius. Such different profiles are dependent upon the operating characteristics and required tolerances of the component being blended. 
         [0050]    The desired contour of the blended area  50  has a depth ratio that is predetermined. The predetermined depth ratio is a ratio of a width of the blended area to a depth of the blended area. In this example, a 200 to 1 depth ratio blend, the material removing surface contour  96  corresponds to a cylinder having a calculated radius R that would be slightly smaller than the radius of bore  48 . Generally, higher depth ratios are more difficult to achieve and verify than a lower depth ratio, such as a 15 to 1 depth ratio, which is typically allowable for less highly stressed components than a rotor of a turbomachine. 
         [0051]    To establish the length L of the blended area  50  (see  FIGS. 2 and 3 ), the carriage  58  is moved back and forth along the rails  62  of the static structure  56  thus performing multiple passes until the desired depth D is achieved. The material removing surface  88  of the belt  74  is pressed upon the face  46  of the rotor or component  38  by a force F that corresponds with the weight of the carriage  58 . Therefore, the center of gravity of the carriage  58  is at about the mid-point of the shoe  86  (previously described to determine depth D). More specifically, the entire weight of the carriage  58  may be generally considered to be a concentrated force exerted upon about the mid-point of the shoe  86  and if the carriage were supported at this point, the carriage would remain in substantial equilibrium in any position within at least the Y-Z coordinate plane (see  FIG. 2 ). To minimize the friction between a belt backing or back surface  98  of the belt  74  and the shoe  86 , the shoe may be made of a polished carbide material, or alternatively, other friction reducing means may be applied such as the application of a graphite tape  100  (see  FIG. 9 ) to the shoe. 
         [0052]    Referring to  FIGS. 7 and 10 , after about each pass of the carriage  58 , the carriage is adjusted to move the car  68  and thus the shoe assembly  72  downward by a fraction of the desired depth D. This adjustment is achieved by an adjustment mechanism  102  that operates against the biasing force of the resilient members  70 . Mechanism  102  may have a pivoting arm  104  attached pivotally to the frame  66  of the carriage  58 . This pivoting connection  106  may be located along the arm generally between a first contact point  108  of the aim that contacts the car  68  and a second contact point  110  of the arm that contacts an adjustment screw  112  threaded into the frame  66 . The adjustment mechanism  102  may also include a depth indicator  114  (e.g. distance micrometer) that notifies the user of the distance that the shoe assembly  72  is moved downward (i.e. fraction of depth D). 
         [0053]    Referring to  FIG. 11 , the downward adjustment by mechanism  102  may be limited by the dimensions and composition of the belt  74 . That is, the maximum depth D″ of each adjustment may be less than the particulate size P of the abrasive material (i.e. thickness of abrasive material) that carries the material removing surface  88 . This assures that the edges of the belt  74  and the belt backing  98  are not directly exposed to the grinding action of the tool  54  and thus maximized the life of the belt and prevents unwanted scoring of the component face  46 . The abrasive material may be made of a ceramic grain bonded to a cloth or velour backing by a resin material. One such exemplary belt is supplied by Hermes Company (Virginia Beach, Va.) and is identified as an “X-flex” belt. 
         [0054]    Referring to  FIG. 12 , another example of the component blending tool to produce a three dimensional blend is illustrated wherein like elements to the previously presented example have like identifying element numbers except with the addition of a prime symbol. In this second example, a component blending tool  54 ′ is useful for blending substantially flat or planar faces of a component. Here, the tool  54 ′ has a static structure  56 ′ having an engagement device  60 ′ that has two suction cups  116  that are pneumatically operative for engagement to the face. The top surfaces of rails  62 ′ may have a radius to partake in producing a 200 to 1 depth ratio spherical blend, both the shoe  86 ′ and the rails  62 ′ will thus have a radius. It is further understood that the contour of the shoe  86 ′ and thus the belt may not have a cylindrical contour as previously described and instead may have any variety of contours (e.g. flat) as dictated by the face geometry and imperfection. Any one of the predetermined blend depth ratios and/or contours can be easily applied by removal of the shoe or shoe assembly from the component blending tool and attachment of another shoe or shoe assembly with an appropriate contour. 
         [0055]    It should be understood that relative positional terms such as “forward,” “aft,” “upper,” “lower,” “above,” “below,” and the like are with reference to the normal operational attitude and should not be considered otherwise limiting. 
         [0056]    It should be understood that like reference numerals identify corresponding or similar elements throughout the several drawings. It should also be understood that although a particular component arrangement is disclosed in the illustrated embodiment, other arrangements will benefit therefrom. 
         [0057]    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 disclosure. 
         [0058]    The foregoing description is exemplary rather than defined by the limitations within. Various non-limiting embodiments are disclosed herein, however, one of ordinary skill in the art would recognize that various modifications and variations in light of the above teachings will fall within the scope of the appended claims. It is therefore to be understood that within the scope of the appended claims, the disclosure may be practiced other than as specifically described. For that reason the appended claims should be studied to determine true scope and content.