Clamping device for turbine blade tenon tooth machining and machining method

Abstract

The invention relates to a clamping device for turbine blade tenon tooth machining and a machining method. The clamping device comprises a double-face steering mechanism and a multi-point flexible clamping mechanism, and the double-face steering mechanism drives the multi-point flexible clamping mechanism to rotate; the multi-point flexible clamping mechanism comprises a mounting base, a first sliding block and a second sliding block, and the first sliding block and the second sliding block are connected to the mounting base in a sliding mode and driven by a linear moving module to move. The first sliding block and the second sliding block are each provided with a plurality of clamping assemblies. The clamping assembly comprises a pressing piece, a force measuring element and a curved surface pressing head, the pressing piece drives the force measuring element and the curved surface pressing head to move in the direction of the connecting line of the first sliding block and the second sliding block, and the force measuring element is connected between the pressing piece and the curved surface pressing head; the clamping assembly corresponding to the first sliding block and the clamping assembly corresponding to the second sliding block are matched to clamp a blade body of the turbine blade. The grinding machining of the tenon teeth on the two sides of the turbine blade can be smoothly completed through one-time clamping, and the machining precision and efficiency can be remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of machining technology, specifically to a clamping device and machining method for machining the tenon teeth of turbine blades. Background Technology

[0002] Turbine blades play a crucial role in aero-engines, and their high performance depends on precise geometry and excellent surface quality. In existing turbine blade tenon grinding processes, traditional clamping methods often only allow for the machining of one side of the tenon at a time, requiring disassembly and re-clamping for grinding the second side. This process not only increases the number of clamping steps but also leads to repetitive positioning errors due to multiple clamping operations, thus affecting the dimensional accuracy and machining efficiency of the final product. Turbine blades, such as... Figure 1 As shown, it generally includes a blade body 91, an upper tenon 92, and a lower tenon 93.

[0003] Currently, the fixtures used for machining the tenons of turbine blades are complex in design and large in size, resulting in low flexibility and difficulty in integration into multi-process machining or automated production lines. Furthermore, the lack of necessary adjustment structures makes it difficult to quickly adapt to workpieces of different sizes or shapes, reducing efficiency during workpiece changeovers. For example, the invention patent with publication number CN113953859B discloses a six-point positioning fixture for blades, which is mainly used for positioning and clamping high-pressure turbine guides; and the invention patent with publication number CN119927836A discloses a miniature pneumatic fixture for stable clamping of aerospace fasteners in compact environments, focusing on miniaturized jaw sleeve design to achieve high-precision clamping in confined spaces. However, these fixtures are insufficient for positioning and clamping complex curved surface parts such as turbine blades with tenons. In addition, existing devices cannot achieve double-sided machining of the tenons in a single clamping operation. Summary of the Invention

[0004] To address the problems existing in the prior art, the present invention aims to provide a clamping device and processing method for machining the tenons of turbine blades, which can smoothly complete the grinding of the tenons on both sides of the turbine blades in a single clamping operation, thereby significantly improving the machining accuracy and efficiency.

[0005] To achieve the above objectives, this invention discloses a clamping device for machining the tenon teeth of turbine blades, comprising a double-sided steering mechanism and a multi-point flexible clamping mechanism. The double-sided steering mechanism drives the multi-point flexible clamping mechanism to rotate. The multi-point flexible clamping mechanism includes a mounting base, a first slider, and a second slider. The first and second sliders are slidably connected to the mounting base and arranged opposite to each other, and both the first and second sliders are driven to move by a linear motion module. Each of the first and second sliders is provided with a plurality of clamping components. Each clamping component includes a clamping element, a force measuring element, and a curved pressure head for pressing the blade body of the turbine blade. The clamping element drives the force measuring element and the curved pressure head to move along the line connecting the first and second sliders. The force measuring element is connected between the clamping element and the curved pressure head. The clamping component corresponding to the first slider cooperates with the clamping component corresponding to the second slider to clamp the blade body of the turbine blade.

[0006] The clamping component is a pneumatic cylinder.

[0007] The mounting base is provided with a first guide for limiting the sliding direction of the first and second sliders, and both the first and second sliders are provided with a second guide for limiting the driving direction of the clamping members; the driving directions of all the clamping members are parallel to each other. The double-sided steering mechanism includes a frame, a drive motor, a planetary transmission assembly, and a cantilever beam. The fixed parts of the drive motor and the planetary transmission assembly are locked to the base. The drive motor is connected to the input end of the planetary transmission assembly, and the output end of the planetary transmission assembly is connected to the cantilever beam and rotates synchronously; the mounting base is locked to the cantilever beam.

[0008] The planetary transmission assembly includes an end cover, a gear ring, a sun gear, a planet carrier, and multiple planet gears. The gear ring is rotatably connected to the end cover. The sun gear is placed in the gear ring and coaxially arranged. The planet gears are placed between the gear ring and the sun gear and mesh with both the gear ring and the sun gear. The planet carrier connects all the planet gears and is fixedly connected to the end cover. The drive motor is connected to the sun gear through a coupling, and the cantilever beam is connected to the gear ring.

[0009] The transmission ratio of the planetary transmission assembly is not less than 5.

[0010] The drive motor is a stepper motor, and the step angle of the stepper motor is no greater than 0.9°.

[0011] The force measuring element is a piezoelectric sensor force measuring instrument.

[0012] It also includes a controller, and the dual-sided steering mechanism, linear motion module, clamping component and force measuring element are all connected to the controller.

[0013] This invention also discloses a method for machining turbine blade tenons, which employs the aforementioned clamping device. The machining method includes the following steps: Step 1: Fix the clamping device onto the machine tool worktable; Step 2: Control the first slider and the second slider to move away from each other so that the turbine blade can be placed between the first slider and the second slider; then control the first slider and the second slider to move closer to each other so that the curved pressure head approaches the blade body of the turbine blade; then control the clamping component to drive the curved pressure head to clamp the blade body of the turbine blade, thus completing the clamping of the turbine blade. Step 3: Activate the double-sided steering mechanism to rotate the turbine blades, and at the same time use the indicator to position the turbine blades so that the surface to be ground on the turbine blades is parallel to the worktable. Step 4: Machining the first tenon teeth on the turbine blades; Step 5: After the first tenon is machined, activate the double-sided steering mechanism to rotate the turbine blade 180°, and then machine the second tenon. Step 6: After the second tenon is processed, keep the double-sided steering mechanism stationary, and release the turbine blade by controlling the movement of the first slider, the second slider and the clamping member. Then re-clamp the turbine blade to be processed and jump to step 4. When the first tenon is the upper tenon, the second tenon is the lower tenon; when the first tenon is the lower tenon, the second tenon is the upper tenon.

[0014] With the above-described scheme, the arrangement of the first and second sliders facilitates the loading and unloading of turbine blades, shortens the stroke of the clamping components, improves clamping efficiency and stability, and reduces costs (by using clamping components with shorter strokes). Multiple independent clamping assemblies, with pressure feedback from force-measuring elements, ensure consistent pressure across all clamping components, thereby achieving adaptive adjustment to the workpiece shape and size during clamping. This ensures uniform force distribution during clamping and reduces the risk of workpiece damage. By driving the clamped turbine blades to rotate and flip through a double-sided steering mechanism, the grinding of the tenons on both sides of the turbine blades can be completed in a single clamping operation, resulting in higher processing efficiency. This invention effectively reduces the number of clamping operations, minimizing the loss of machining accuracy due to repeated clamping, thus ensuring machining precision. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of turbine blades; Figure 2 This is a schematic diagram of the present invention; Figure 3 This is a schematic diagram of a planetary gear assembly; Figure 4 This is a schematic diagram of the clamping assembly.

[0016] Explanation of key figure labels: Frame 10, mounting hole 11; Drive motor 20; Planetary gear assembly 30, end cap 31, gear ring 32, planet gear 33, sun gear 34, planet carrier 35; 40mm cantilever beam; Guide rail 50; First slider 60; Second slider 70; Clamping assembly 80, clamping component 81, force measuring element 82, curved pressure head 83; Turbine blade 90, blade body 91, upper tenon 92, lower tenon 93; Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0018] like Figure 1-4 As shown, the present invention discloses a clamping device for machining the tenon teeth of a turbine blade 90, which includes a controller, a double-sided steering mechanism and a multi-point flexible clamping mechanism. The double-sided steering mechanism drives the multi-point flexible clamping mechanism to rotate, and the multi-point flexible clamping mechanism is used to stably and reliably clamp the turbine blade 90.

[0019] Specifically, the double-sided steering mechanism includes a frame 10, a drive motor 20, a planetary transmission assembly, and a cantilever beam 40. The drive motor 20 is connected to a controller. The frame 10 has multiple mounting holes 11 for connection to a machine tool table. The planetary transmission assembly includes an end cover 31, a gear ring 32, a sun gear 34, a planet carrier 35, and multiple planet gears 33. The end cover 31 (i.e., the fixing part of the planetary transmission assembly) is locked to the frame 10. The gear ring 32 is rotatably connected to the end cover 31. The sun gear 34 is placed in the gear ring 32 and coaxially arranged. The planet gears 33 are placed between the gear ring 32 and the sun gear 34, meshing with both the gear ring 32 and the sun gear 34. The planet carrier 35 connects all the planet gears 33 and is fixedly connected to the end cover 31. The base of the drive motor 20 is locked onto the frame 10. The output shaft of the drive motor 20 is connected to the sun gear 34 via a coupling, thereby driving the sun gear 34 to rotate. The sun gear 34 is the input end of the planetary transmission assembly. The cantilever beam 40 is connected to the gear ring 32 and rotates synchronously. The gear ring 32 is the output end of the planetary transmission assembly.

[0020] In this case, the transmission ratio of the planetary transmission assembly is required to be no less than 5. For example, the sun gear 34 is designed with 15 teeth, the planet gear 33 with 30 teeth, and the ring gear 32 with 75 teeth, resulting in a tooth ratio of 1:2:5, or a transmission ratio of 5 (5:1). A larger transmission ratio allows the minute rotation at the input end to be amplified at the output end, thereby controlling the steering angle more precisely. The angle error is controlled within ±0.1°. After the blade completes a 180° rotation, the spatial positional relationship of the tenon teeth on both sides can be ensured to be accurate. The drive motor 20 is a stepper motor with a step angle of no more than 0.9° to provide high positional resolution. This ensures that the transmission error will not significantly affect the accuracy during a 360° rotation. Combined with the high-precision indexing capability of the planetary gear structure, it has excellent ±0.1° repeatability after a 180° rotation, providing a core guarantee for the spatial positional consistency of the turbine blade 90 during continuous double-sided machining.

[0021] The multi-point flexible clamping mechanism includes a mounting base, a first slider 60, and a second slider 70. The mounting base is locked onto the cantilever beam 40. The first slider 60 and the second slider 70 are arranged opposite to each other on the mounting base and are slidably connected to the mounting base. The mounting base is provided with a first guide member to limit the sliding direction of the first slider 60 and the second slider 70. The first guide member can be a slide groove or a guide rail 50. In this case, the first slider 60 and the second slider 70 share a first guide member, and the guide rail 50 is directly regarded as the mounting base and illustrated. By setting the first guide member, good positioning accuracy (±0.005mm) can be ensured.

[0022] The first slider 60 and the second slider 70 each correspond to a linear motion module. The two linear motion modules drive the first slider 60 and the second slider 70 to move respectively. The linear motion modules also serve to stop the first slider 60 and the second slider 70. The linear motion module can be a pneumatic cylinder, which is connected to and controlled by a controller. The linear motion module is mounted on a mounting base.

[0023] Several clamping assemblies 80 are provided on both the first slider 60 and the second slider 70. These clamping assemblies 80 are independent of each other. Each clamping assembly 80 includes a clamping member 81, a force-measuring element 82, and a curved pressure head 83 for pressing the blade body 91 of the turbine blade 90. The clamping member 81 drives the force-measuring element 82 and the curved pressure head 83 to move along the line connecting the first slider 60 and the second slider 70. Specifically, the clamping member 81 corresponding to the first slider 60 drives the curved pressure head 83 connected to it to move relative to the second slider 70, and vice versa. The clamping member 81 can be a pneumatic cylinder and is connected to a controller. Ideally, the driving directions of all clamping members 81 should be parallel. To ensure stable driving directions, second guide members can be provided on both the first slider 60 and the second slider 70 to limit the driving direction of the clamping members 81. The second guide members can refer to the first guide members.

[0024] Force measuring element 82 is connected between the movable part of clamping member 81 and curved pressure head 83. Force measuring element 82 is used to provide real-time feedback of the pressure (i.e., clamping force) between curved pressure head 83 and turbine blade 90. Force measuring element 82 can be a piezoelectric sensor force gauge, which can effectively acquire high-frequency, high-dynamic force signals during the processing vibration process in real time, and can synthesize the acquired triaxial force signals to obtain the directionality of the clamping force. Force measuring element 82 is connected to a controller. The force gauge has a measurement range of 0-3000N and a measurement accuracy of 0.5N to maintain the preset clamping force to ensure the safety and reliability of the clamping process and effectively prevent the workpiece from deforming during the clamping process. During the processing, the controller receives real-time feedback from the high-precision force gauge. When the clamping force fluctuates beyond the ±2N threshold due to processing vibration or changes in cutting force, the clamping component 81 compensates for the pressure within 50ms to ensure the accuracy of the processing. In the processing condition where the cutting force will inevitably increase, the clamping component 81 does not mechanically maintain the initial clamping force, but intelligently adjusts it according to the preset safe clamping force range to prevent plastic deformation of the workpiece and slippage and instability.

[0025] The turbine blade 90 is clamped by the first slider 60, the second slider 70, and the clamping assembly 80. The force measuring element 82 can provide feedback on the contact pressure between each clamping assembly 80 and the blade body 91. With the contact pressure between each clamping assembly 80 and the blade body 91 as a constant value, such as 200N, the stroke of the clamping member 81 is controlled to ensure that the turbine blade 90 is subjected to uniform force during clamping.

[0026] This invention also discloses a method for machining the 90 tenon teeth of a turbine blade, which employs the aforementioned clamping device and specifically includes the following steps: Step 1: Fix the clamping device to the machine tool worktable and bolt it to the machine tool worktable through the assembly hole 11 on the frame 10.

[0027] Step 2: Control the linear motion module to move the first slider 60 and the second slider 70 away from each other, allowing the turbine blade 90 to be placed between them. Then, control the first slider 60 and the second slider 70 to move closer together, bringing the curved pressure head 83 closer to the blade body 91 of the turbine blade 90. Next, control the clamping member 81 to drive the curved pressure head 83 to clamp the blade body 91 of the turbine blade 90, completing the clamping of the turbine blade 90. During clamping, ensure the clamping force is stable within the range of 200±2N to guarantee stable workpiece clamping, prevent deformation during processing, and ensure processing accuracy and workpiece quality.

[0028] Step 3: Start the drive motor 20 to rotate the clamped turbine blade 90, and simultaneously use the indicator to position the turbine blade 90 so that the surface to be ground on the turbine blade 90 is parallel to the worktable. To ensure the machining accuracy of the tenon teeth, the parallelism error must be controlled within ±0.002mm.

[0029] Step 4: Machin the first tenon teeth on the turbine blade 90.

[0030] Step 5: After the first tenon is machined, start the double-sided steering mechanism to rotate the turbine blade 90° 180°, ensuring that the rotation angle error is strictly controlled within ±0.1° and that its parallelism error still meets the requirement of ±0.002mm. Then proceed with the machining of the second tenon.

[0031] Step 6: After the second tenon is machined, keep the double-sided steering mechanism stationary. By controlling the first slider 60 and the second slider 70 to move away from each other, and by controlling the clamping member 81 to reset (retract), the clamping of the turbine blade 90 is released. Then, the turbine blade 90 to be machined is re-clamped, and the process jumps to step 4. This operation ensures that the machining position remains unchanged, avoiding the need for secondary leveling, thereby further improving machining efficiency and accuracy, and reducing errors that may be caused by secondary leveling.

[0032] It should be noted that when the first tenon is the upper tenon 92, the second tenon is the lower tenon 93; when the first tenon is the lower tenon 93, the second tenon is the upper tenon 92.

[0033] The key to this invention lies in the arrangement of the first slider 60 and the second slider 70, which facilitates the loading and unloading of turbine blades, shortens the stroke of the clamping member 81, improves clamping efficiency and stability, and reduces costs (by using a clamping member 81 with a shorter stroke). Multiple independent clamping assemblies 80, with pressure feedback from the force measuring element 82, ensure consistent pressure across all clamping assemblies 80, thereby achieving adaptive adjustment to the workpiece shape and size during clamping. This ensures uniform force distribution during clamping and reduces the risk of workpiece damage. The double-sided steering mechanism drives the clamped turbine blade 90 to rotate and flip, enabling the grinding of the tenons on both sides of the turbine blade 90 to be completed in a single clamping operation, resulting in higher processing efficiency. This invention effectively reduces the number of clamping operations, minimizing the loss of machining accuracy due to repeated clamping, thus ensuring machining precision.

[0034] The above description is merely an embodiment of the present invention and does not constitute any limitation on the technical scope of the present invention. Therefore, any minor modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A clamping device for machining tenons on turbine blades, characterized in that: The device includes a double-sided steering mechanism and a multi-point flexible clamping mechanism. The double-sided steering mechanism drives the multi-point flexible clamping mechanism to rotate. The multi-point flexible clamping mechanism includes a mounting base, a first slider, and a second slider. The first and second sliders are slidably connected to the mounting base and arranged opposite to each other. Both the first and second sliders are driven to move by a linear motion module. Each of the first and second sliders is provided with a plurality of clamping components. Each clamping component includes a clamping element, a force measuring element, and a curved pressure head for pressing the blade body of the turbine blade. The clamping element drives the force measuring element and the curved pressure head to move along the line connecting the first and second sliders. The force measuring element is connected between the clamping element and the curved pressure head. The clamping component corresponding to the first slider cooperates with the clamping component corresponding to the second slider to clamp the blade body of the turbine blade.

2. The clamping device for machining turbine blade tenons according to claim 1, characterized in that: The clamping component is a pneumatic cylinder.

3. The clamping device for machining turbine blade tenons according to claim 1, characterized in that: The mounting base is provided with a first guide for limiting the sliding direction of the first slider and the second slider, and both the first slider and the second slider are provided with a second guide for limiting the driving direction of the clamping member; the driving directions of all the clamping members are parallel to each other.

4. The clamping device for machining turbine blade tenons according to claim 1, characterized in that: The dual-sided steering mechanism includes a frame, a drive motor, a planetary transmission assembly, and a cantilever beam. The drive motor and the fixed part of the planetary transmission assembly are locked on the base. The drive motor is connected to the input end of the planetary transmission assembly, and the output end of the planetary transmission assembly is connected to the cantilever beam and rotates synchronously. The mounting base is locked on the cantilever beam.

5. A clamping device for machining turbine blade tenons according to claim 4, characterized in that: The planetary transmission assembly includes an end cover, a gear ring, a sun gear, a planet carrier, and multiple planet gears. The gear ring is rotatably connected to the end cover. The sun gear is placed in the gear ring and coaxially arranged. The planet gears are placed between the gear ring and the sun gear and mesh with both the gear ring and the sun gear. The planet carrier connects all the planet gears and is fixedly connected to the end cover. The drive motor is connected to the sun gear through a coupling, and the cantilever beam is connected to the gear ring.

6. A clamping device for machining turbine blade tenons according to claim 4 or 5, characterized in that: The transmission ratio of the planetary transmission assembly is not less than 5.

7. A clamping device for machining turbine blade tenons according to claim 4, characterized in that: The drive motor is a stepper motor, and the step angle of the stepper motor is no greater than 0.9°.

8. A clamping device for machining turbine blade tenons according to claim 1, characterized in that: The force measuring element is a piezoelectric sensor force measuring instrument.

9. A clamping device for machining turbine blade tenons according to claim 1, characterized in that: It also includes a controller, and the dual-sided steering mechanism, linear motion module, clamping component and force measuring element are all connected to the controller.

10. A method for machining the tenon teeth of a turbine blade, characterized in that, The processing method, which employs the clamping device according to any one of claims 1-9, includes the following steps: Step 1: Fix the clamping device onto the machine tool worktable; Step 2: Control the first slider and the second slider to move away from each other so that the turbine blade can be placed between the first slider and the second slider; then control the first slider and the second slider to move closer to each other so that the curved pressure head approaches the blade body of the turbine blade; then control the clamping component to drive the curved pressure head to clamp the blade body of the turbine blade, thus completing the clamping of the turbine blade. Step 3: Activate the double-sided steering mechanism to rotate the turbine blades, and at the same time use the indicator to position the turbine blades so that the surface to be ground on the turbine blades is parallel to the worktable. Step 4: Machining the first tenon teeth on the turbine blades; Step 5: After the first tenon is machined, activate the double-sided steering mechanism to rotate the turbine blade 180°, and then proceed with the machining of the second tenon. Step 6: After the second tenon is processed, keep the double-sided steering mechanism stationary, and release the turbine blade by controlling the movement of the first slider, the second slider and the clamping member. Then re-clamp the turbine blade to be processed and jump to step 4. When the first tenon is the upper tenon, the second tenon is the lower tenon; when the first tenon is the lower tenon, the second tenon is the upper tenon.

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