Mechanical Motion Cam Track Follower

Abstract

The present application provides a variable spray system for spraying a sprayable material onto a workpiece at different angles. The variable spray system can include a linear actuator, a cam follower assembly, and a spray arm assembly. The linear actuator drives the cam follower assembly such that the cam follower assembly positions the spray arm assembly at a first angle relative to the workpiece during a first stroke of the linear actuator and positions the spray arm assembly at a second angle relative to the workpiece during a second stroke of the linear actuator.

Description

[Technical Field]

[0001] This application and the resulting patent generally relate to methods and systems for performing repetitive tasks, and more particularly to methods and systems for the rotation and translation of tools, such as shot peening tools for turbine engine rotor blades. [Background technology]

[0002] Generally described, turbine engine rotor blades include an airfoil and a dovetail extending outward from a support platform. The dovetail is configured with an axial lobe or tang for mounting each blade within a corresponding dovetail slot in the periphery of a supporting rotor disk. During operation, energy is extracted from hot combustion gases flowing past the turbine rotor blades, which, in a typical configuration, rotate the supporting rotor disk to power the compressor. The rotor blades are subjected to centrifugal loads during operation. These loads are transferred radially inward through the support dovetail to the periphery of the supporting rotor disk.

[0003] Turbine rotor blades are typically formed from high-strength superalloy materials that have high strength at the high temperatures typically found in turbines. To further increase the strength of turbine rotor blades, various surfaces of the dovetails can be shot peened in one of the final manufacturing steps of producing the blades. Shot peening is a process in which metal shot is discharged onto the surface of a metal workpiece in a pressurized air stream to plastically deform its surface layer and introduce residual compressive stresses. The residual compressive stresses reduce stresses induced in the component during operation, such as in the rotating environment of a gas turbine engine.

[0004] Uniform shot peening of the entire turbine blade dovetail can provide maximum strength and a correspondingly long service life for the blade during operation. To ensure uniform coverage, many types of shot peening equipment use multiple nozzles positioned at various angles. However, each additional nozzle and associated components increases the overall cost, complexity, and efficiency of the equipment. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] U.S. Patent Application Publication No. 2008-0268757 Summary of the Invention

[0006] Thus, the present application and resultant patent provide a variable spray system for spraying a sprayable material onto a workpiece at different angles. The variable spray system can include a linear actuator, a cam follower assembly, and a spray arm assembly. The linear actuator drives the cam follower assembly such that the cam follower assembly positions the spray arm assembly at a first angle relative to the workpiece during a first stroke of the linear actuator and positions the spray arm assembly at a second angle relative to the workpiece during a second stroke of the linear actuator. The workpiece can be a turbine blade dovetail, and the sprayable material can be shot peened.

[0007] The present application and resultant patent further provides a method for positioning a nozzle driven by a shaft of a cam follower assembly at different angles around a workpiece, the method may include driving the shaft in an upward direction, whereby driving the shaft in the upward direction causes the cam follower assembly to rotate the shaft and the nozzle at a first angle, and driving the shaft in a downward direction, whereby driving the shaft in the downward direction causes the cam follower assembly to rotate the shaft and the nozzle at a second angle.

[0008] The present application and resultant patent further provide a variable spray system for spraying shot peening at different angles onto a rotor blade dovetail. The variable spray system can include a linear actuator, a cam follower assembly, and a spray arm having a nozzle. The linear actuator drives the cam follower assembly such that the cam follower assembly positions the spray arm and nozzle at a first angle relative to the dovetail during a first stroke of the linear actuator and positions the spray arm and nozzle at a second angle relative to the dovetail during a second stroke of the linear actuator.

[0009] These and other features and improvements of the present application and the resulting patent will become apparent to those skilled in the art upon review of the following detailed description taken in conjunction with the several drawings and the appended claims. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram of a gas turbine engine including a compressor, a combustor, a turbine, and an external load. [Figure 2] FIG. 2 is a perspective view of a turbine rotor blade. [Figure 3] FIG. 1 is a side view of a variable atomization system that may be described herein. [Figure 4] FIG. 4 is a cross-sectional view of the variable atomization system of FIG. 3 taken along line 4-4. [Figure 5]FIG. 4 is a perspective view of a cam follower assembly of the variable atomization system of FIG. 3. [Figure 6] FIG. 6 is a plan view of the cam track of the cam follower assembly of FIG. 5. [Figure 7] 4 is a schematic diagram of the spray nozzle of the variable spray system of FIG. 3 positioned at different angles relative to the workpiece. DETAILED DESCRIPTION OF THE INVENTION

[0011] Referring now to the drawings, in which like numerals refer to like elements throughout the several views, FIG. 1 illustrates a schematic diagram of a gas turbine engine 10 that may be used herein. The gas turbine engine 10 may include a compressor 15. The compressor 15 compresses an incoming flow of air 20. The compressor 15 delivers the compressed flow of air 20 to a number of combustor cans 25. The combustor cans 25 mix the compressed flow of air 20 with a pressurized flow of fuel 30 and ignite the mixture to generate a flow of hot combustion gases 35. While only a single combustor can 25 is shown, the gas turbine engine 10 may include any number of combustor cans 25 arranged, such as in a circumferential array. Alternatively, the combustor 25 may be an annular combustor. The flow of combustion gases 35 is then delivered to a turbine 40. The flow of combustion gases 35 drives the turbine 40 to generate mechanical work. The mechanical work generated in the turbine 40 drives the compressor 15 via a rotor shaft 45, which drives an external load 50, such as an electrical generator.

[0012] The gas turbine engine 10 may use natural gas, various types of synthetic gas, liquid fuels, and / or other types of fuels and blends thereof. The gas turbine engine 10 may be any one of several different gas turbine engines offered by General Electric Company of Schenectady, New York, including, but not limited to, a 7-series or 9-series heavy-duty gas turbine engine and the like, and may be part of a simple-cycle or combined-cycle power generation system. The gas turbine engine 10 may have different configurations and may use other types of components. Other types of gas turbine engines may also be used herein. Multiple gas turbine engines, other types of turbines, and other types of power generation equipment may also be used together herein.

[0013] As noted above, a turbine engine rotor blade includes a support platform and an airfoil extending outwardly from a dovetail. To further increase the strength of the turbine rotor blade, various surfaces of the dovetail may be shot peened to reduce stresses therein. FIG. 2 illustrates a workpiece 55 in the form of a gas turbine engine rotor blade 60. The rotor blade 60 includes an airfoil 65 extending outwardly from a support platform 70 having an integrally formed dovetail 75. The dovetail 75 may be conventionally configured as an axial-entry dovetail with a plurality of serrations or dovetail lobes configured to mount the rotor blade to the periphery of a supporting rotor disk (not shown) having a corresponding axial dovetail slot extending around its periphery. Other types of rotor blades 60, etc., may also be used herein.

[0014] 3-6 illustrate one example of a variable spray system 100 that may be described herein. The variable spray system 100 may be used to shot peen a workpiece 55, such as a dovetail 75 of a rotor blade 60. Other types of workpieces 55 and other types of configurations may be used herein. The variable spray system 100 may be in communication with a shot peening material source 110 having a volume of shot peening material 120 therein. Other types of sprayable material 125 may also be used herein. The variable spray system 100 may be in communication with the shot peening material source 110 via a flexible hose 130 or the like.

[0015] The variable spray system 100 includes a frame 140. The frame 140 may have any suitable size, shape, or configuration. A cam follower assembly 150 may be mounted within the frame 140. The cam follower assembly 150 operates a spray arm assembly 160 via a linear actuator 170. The linear actuator 170 may be of conventional design having a drive motor 180 attached to a linear motion shaft 190. The linear motion shaft 190 may raise and lower a mounted lift plate 200. The length of travel of the lift plate 200 may be controlled by a limit switch (not shown) located in a T-slot mount 210 or the like. Other types of linear drive devices may be used herein. Other components and other configurations may be used herein.

[0016] The cam follower assembly 150 includes a vertically driven shaft 220. The shaft 220 may be disposed on the lift plate 200 of the linear actuator 170 for vertical movement therewith. A track roller 230 may be attached to the shaft 220 via a shaft coupling 240. The shaft 220 and track roller 230 may be positioned within a cam follower tube 250. The cam follower tube 250 defines a track 260 therein. The track 260 may be generally in the shape of a parallelogram 270 with an upwardly facing vertical edge 280, an upwardly facing angled edge 290, a top recess 300, a downwardly facing vertical edge 310, a downwardly facing angled edge 320, and a bottom recess 330. The configuration of the track 260 and the edges therein may vary depending on the desired resulting motion. Specifically, track roller 230 is driven by shaft 220 up and down vertically facing edge 280 and vertically facing down edge 310, while track roller 230 is driven at an angle along angled upwardly facing edge 290 and angled downwardly facing edge 320. This angled motion causes track roller 230 to rotate shaft 220. Other components and configurations may be used herein.

[0017] The spray arm assembly 160 is attached to the shaft 220 and can move vertically and rotationally therewith. In this example, the spray arm assembly 160 can include a horizontal arm 340, an inclined arm 350, and a vertical arm 360. The length of each of the arms 340, 350, 360 can vary depending on the desired resulting movement. The horizontal arm 340 can be attached to the shaft 220 for movement therewith. The vertical arm 360 can be attached to a spray nozzle 370. The spray nozzle 370 can be in communication with the shot peening material source 110 via the flexible hose 130. The spray nozzle 370 can be of conventional design. Other components and configurations can be used herein.

[0018] 7, the variable spray system 100 can be used to spray shot peening material 120 or other types of sprayable material 125 onto a rotor blade dovetail 75 or other type of workpiece 55. Specifically, the variable spray system 100 can spray shot peening material 120 from bottom to top on one side of the dovetail 75, or at a first angle 380, then rotate to spray shot peening material 120 from top to bottom on the other side, or at a second angle 390, and then rotate back to the starting position. In the upward or first stroke 400, the linear actuator 170 raises the shaft 220 as the track roller 230 travels along the upward vertical edge 280 of the track 260. The linear actuator 170 continues to raise the shaft 220 as the track rollers 230 travel along the upwardly sloping edge 290 of the track 260, causing the track rollers 230 to rotate until they reach the top recess 300. On the downward or second stroke 410, the reverse occurs, with the linear actuator 170 lowering the shaft 220 as the track rollers 230 travel along the downwardly sloping vertical edge 310 of the track. The linear actuator 170 continues to lower the shaft 220 as the track rollers 230 travel along the downwardly sloping edge 320 of the track 260, causing the track rollers 230 to rotate until they return to the bottom recess 330.

[0019] This motion can then be repeated without any reset as the linear actuator 120 raises and lowers the shaft 220. Thus, the reciprocating motion of the linear actuator 170 provides vertical and rotational motion to the shaft 220 and, therefore, the spray arm assembly 160 and the nozzle 370. The nozzle 370 can make multiple passes on either side of the dovetail 75 or for both angles 380, 390, as desired.

[0020] The length of each stroke of the linear actuator 170, the length of the vertical edges 280, 310 of the track 260, the length and angle of the inclined edges 290, 320 of the track 260, and the length of the arms 340, 350, 360 of the spray arm assembly 160 can all be varied individually or in combination to change the vertical distance traveled by the nozzle 370 and the degree of rotation of the nozzle 370 around the dovetail 75 or other type of workpiece 55.

[0021] Thus, the variable spray system 100 utilizes the linear actuator 170 and cam follower assembly 150 to generate a repetitive rotational actuation, thus simplifying the variable spray system 100 by reducing the number of components within the variable spray system 100 and therefore eliminating waste. As noted above, the shot peening process typically required two nozzles instead of the single nozzle 370 used herein. The combination of the linear actuator 170 and cam follower assembly 150 may be used in any mechanical actuation application, such as machines in a manufacturing environment that require repetitive motion. This combination limits waste (energy, hardware, motion, control) by utilizing a mechanical mechanism to generate controlled rotational motion from linear motion.

[0022] It should be clear that the foregoing relates only to certain embodiments of this application and the resulting patent. Those skilled in the art may make numerous changes and modifications herein without departing from the general spirit and scope of the invention as defined by the following claims and their equivalents.

[0023] Further aspects of the invention are provided by the subject matter of the following clauses.

[0024] 1. A variable spray system for spraying a sprayable material onto a workpiece at different angles, comprising: a linear actuator; a cam follower assembly; and a spray arm assembly, wherein the linear actuator drives the cam follower assembly such that the cam follower assembly positions the spray arm assembly at a first angle relative to the workpiece on a first stroke of the linear actuator and positions the spray arm assembly at a second angle relative to the workpiece on a second stroke of the linear actuator.

[0025] 2. The variable spray system described in clause 1, wherein the cam follower assembly comprises a shaft extending between the linear actuator and the spray arm assembly.

[0026] 3. The variable spray system of any of the preceding clauses, wherein the linear actuator comprises a lift plate, and the lift plate raises and lowers the shaft.

[0027] 4. The variable spray system of any preceding clause, wherein the cam follower assembly comprises a track roller mounted on a shaft.

[0028] 5. A variable spray system of any preceding clause wherein the cam follower assembly comprises a track and the track roller advances along the track.

[0029] 6. The track includes a parallelogram shape, variable spray system of any of the preceding clauses.

[0030] 7. The variable spray system of any preceding clause, wherein the track has an upward vertical edge, an upward beveled edge, a downward vertical edge, and a downward beveled edge.

[0031] 8. A variable spray system of any preceding clause wherein the track roller travels along the upward vertical edge and the upward inclined edge of the track during the first stroke of the linear actuator.

[0032] 9. A variable spray system of any preceding clause wherein the track roller rotates the shaft while the track roller travels along the upwardly sloping edge of the track.

[0033] 10. A variable spray system of any preceding clause wherein the track roller travels along the downward vertical edge and the downward inclined edge of the track during the second stroke of the linear actuator.

[0034] 11. A variable spray system of any preceding clause wherein the track roller rotates the shaft while the track roller travels along the downwardly sloping edge of the track.

[0035] 12. The variable spray system of any preceding clause, wherein the spray arm assembly comprises a nozzle.

[0036] 13. The workpiece is a variable spray system of any preceding clause, including a rotor blade dovetail.

[0037] 14. The variable spray system of any preceding clause, wherein the spray material comprises a shot peening material.

[0038] 15. A method for positioning a nozzle driven by a shaft of a cam follower assembly at different angles around a workpiece, the method comprising: driving the shaft upward, and by driving the shaft upward, the cam follower assembly causes the shaft to rotate at a first angle; driving the shaft downward, and by driving the shaft downward, the cam follower assembly causes the shaft to rotate at a second angle.

[0039] 16. A variable spray system for spraying a rotor blade dovetail with shot peening at different angles, comprising: a linear actuator; a cam follower assembly; and a spray arm having a nozzle, wherein the linear actuator drives the cam follower assembly such that the cam follower assembly positions the spray arm and nozzle at a first angle relative to the dovetail on a first stroke of the linear actuator and positions the spray arm and nozzle at a second angle relative to the dovetail on a second stroke of the linear actuator.

[0040] 17. The variable spray system of any preceding clause, wherein the cam follower assembly comprises a shaft extending between the linear actuator and the spray arm.

[0041] 18. The variable spray system of any preceding clause, wherein the cam follower assembly comprises a track roller mounted on a shaft, and the cam follower assembly comprises a track.

[0042] 19. The variable spray system of any preceding clause, wherein the track has an upward vertical edge, an upward beveled edge, a downward vertical edge, and a downward beveled edge.

[0043] 20. The variable spray system of any preceding clause, wherein the track roller rotates the shaft at a first angle while the track roller travels along the upwardly sloping edge of the track, and the track roller rotates the shaft at a second angle while the track roller travels along the downwardly sloping edge of the track. [Explanation of symbols]

[0044] 10. Gas turbine engine 15 Compressor 20. Air 25 Combustor can 30 fuel 35 Hot combustion gases 40 Turbine 55 workpieces 60 rotor blades 65 Airfoil 70 Support Platform 75 Dovetail 100 Variable Spray System 110 Shot Peening Material Source 120 Shot Peening Materials 125 Sprayable Materials 130 Flexible hose 140 frames 150 Cam follower assembly 160 Spray Arm Assembly 170 Linear Actuator 180 drive motor 190 Linear motion shaft 200 lift plate 210 T-slot mount 220 shaft 230 Track Roller 250 Cam follower tube 260 tracks 270 parallelogram 280 Upward vertical edge 290 Upward sloping edge 300 Upper recess 310 Downward vertical edge 320 downward sloping edge 330 Bottom recess 340 horizontal arm 350 tilt arm 360 Vertical Arm 370 spray nozzle 380 First Angle 390 Second Angle 400 Upward or First Stroke 410 Downward or Second Stroke

Claims

1. A variable spray system (100) for spraying a sprayable material (125) onto a workpiece (55) at different angles, comprising: a linear actuator (170); a cam follower assembly (150); a spray arm assembly (160); The linear actuator (170) drives the cam follower assembly (150) such that the cam follower assembly (150) positions the spray arm assembly (160) at a first angle (380) relative to the workpiece (55) during a first stroke (400) of the linear actuator (170), and positions the spray arm assembly (160) at a second angle (390) relative to the workpiece (55) during a second stroke (410) of the linear actuator (170).

2. The variable spray system (100) of claim 1, wherein the cam follower assembly (150) comprises a shaft (220) extending between the linear actuator (170) and the spray arm assembly (160).

3. The variable spray system (100) of claim 2, wherein the linear actuator (170) comprises a lift plate (200), the lift plate (200) raising and lowering the shaft (220).

4. The variable spray system (100) of claim 2, wherein the cam follower assembly (150) comprises a track roller (230) mounted on the shaft (220).

5. The variable spray system (100) of claim 4, wherein the cam follower assembly (150) comprises a track (260), and the track roller (230) travels along the track (260).

6. The variable spray system (100) of claim 5, wherein the track (260) comprises a parallelogram shape (270).

7. The variable spray system (100) of claim 5, wherein the track (260) comprises an upward vertical edge (280), an upward beveled edge (290), a downward vertical edge (310), and a downward beveled edge (320).

8. 8. The variable spray system of claim 7, wherein the track roller travels along the upward vertical edge and the upward inclined edge of the track during the first stroke of the linear actuator.

9. 9. The variable spray system of claim 8, wherein the track roller rotates the shaft while the track roller travels along the upwardly inclined edge of the track.

10. 8. The variable spray system of claim 7, wherein the track roller travels along the downward vertical edge and the downward inclined edge of the track during the second stroke of the linear actuator.

11. 11. The variable spray system of claim 10, wherein the track roller rotates the shaft while the track roller travels along the downwardly inclined edge of the track.

12. The variable spray system (100) of claim 1, wherein the spray arm assembly (160) comprises a nozzle (370).

13. The variable spray system (100) of claim 1, wherein the workpiece (55) comprises a dovetail (75) of a rotor blade (60).

14. The variable spray system (100) of claim 1, wherein the sprayable material (125) comprises a shot peening material (120).

15. 1. A method for positioning a nozzle (370) driven by a shaft (220) of a cam follower assembly (150) at different angles around a workpiece (55), comprising: Driving the shaft (220) upward; Driving said shaft (220) in said upward direction causes said cam follower assembly (150) to rotate said shaft (220) through a first angle (380); Driving the shaft (220) downward; driving said shaft (220) in said downward direction, causing said cam follower assembly (150) to rotate said shaft (220) through a second angle (390).

16. 1. A variable spray system (100) for spraying a dovetail (75) of a rotor blade (60) with shot peening at different angles, comprising: a linear actuator (170); a cam follower assembly (150); a spray arm having a nozzle (370); The linear actuator (170) drives the cam follower assembly (150) such that the cam follower assembly (150) positions the spray arm and the nozzle (370) at a first angle (380) relative to the dovetail (75) during a first stroke (400) of the linear actuator (170), and positions the spray arm and the nozzle (370) at a second angle (390) relative to the dovetail (75) during a second stroke (410) of the linear actuator (170).

17. The variable spray system (100) of claim 16, wherein the cam follower assembly (150) comprises a shaft (220) extending between the linear actuator (170) and the spray arm.

18. 20. The variable spray system of claim 17, wherein the cam follower assembly comprises a track roller mounted on the shaft, the cam follower assembly comprising a track.

19. 20. The variable spray system (100) of claim 18, wherein the track (260) comprises an upward vertical edge (280), an upward beveled edge (290), a downward vertical edge (310), and a downward beveled edge (320).

20. 20. The variable spray system of claim 19, wherein the track roller rotates the shaft at the first angle while the track roller travels along the upwardly inclined edge of the track, and the track roller rotates the shaft at the second angle while the track roller travels along the downwardly inclined edge of the track.

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