Machining tool and machining method for blade root of fork type regulating stage moving blade

Abstract

The invention relates to a processing tool and a processing method for a blade root of a fork type regulating stage moving blade. The processing tool comprises a base, a steam outlet side locking assembly, a radial side pressing assembly, a steam outlet side regulating assembly and a length regulating assembly, the steam outlet side locking assembly is arranged on the inner side of the base, one end of the steam outlet side locking assembly is matched with the base, the other end of the steam outlet side locking assembly is matched with the steam outlet side adjusting assembly, and the steam outlet side adjusting assembly is arranged between the steam outlet side locking assembly and the moving blade; the radial side pressing assembly is arranged at the upper end of the base, one end of the radial side pressing assembly is matched with the base, and the other end of the radial side pressing assembly is matched with the inner radial faces of the blade root and the blade crown of the moving blade. The length adjusting assembly is arranged between the base and the end face of the blade crown of the moving blade. According to the invention, the base, the steam outlet side locking assembly, the radial side pressing assembly, the steam outlet side adjusting assembly and the length adjusting assembly are integrated, so that an integrated structure of three-dimensional positioning, two-way clamping and two-dimensional adjusting is formed, and the technical problem of poor universality of a traditional tool is solved.

Description

Technical Field

[0001] This invention relates to the field of blade processing technology, specifically to a tooling and processing method for processing the root of a fork-shaped regulating stage moving blade. Background Technology

[0002] The regulating stage blades of a steam turbine are the core components of the first stage at the steam inlet of the unit. They bear the critical task of converting the energy of high-temperature and high-pressure steam into mechanical energy. They need to be adaptable to variable load regulation and withstand extreme conditions such as high centrifugal force, aerodynamic excitation force, and high-temperature oxidation and corrosion. The comprehensive stress is 1.5-2 times that of other blade stages. Their forked structure evolved from the earlier T-shaped and fungus-shaped blade roots. By distributing force evenly across multiple teeth, they reduce the stress per unit area. Furthermore, the circumferential assembly design facilitates individual replacement, resulting in significantly higher maintenance efficiency than other structures, making them the preferred choice for the regulating stage of high-parameter units. With the upgrading and iteration of the unit parameters, the manufacturing tolerance of some forked teeth is ≤0.015mm. Due to this extremely small tolerance, they are prone to deformation during clamping, requiring breakthroughs in precision machining and stability control technologies.

[0003] The main challenge in machining the moving blades of the fork-type regulating stage lies in the blade root section, which requires various machining methods and tooling fixtures. However, existing tooling fixtures lack versatility; different blade models require different fixtures for adaptation, increasing machining and time costs. Furthermore, the positioning and clamping methods between the fixtures and the moving blades are not precise enough, making the blades prone to misalignment and affecting machining accuracy. In the blade root section, the minimum tolerance between the forks is only 0.015mm. Regarding machining methods, some use slow wire EDM to ensure this, while others use high-speed steel combination milling cutters. While these methods can guarantee machining progress, they place high demands on the accuracy of the equipment and the assembly of the combination cutters. Summary of the Invention

[0004] This invention addresses the technical problems existing in the prior art by providing a tooling and method for machining the root of a fork-shaped regulating stage moving blade.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: A fork-shaped regulating stage moving blade root machining fixture includes a base, a steam outlet side locking assembly, a radial side pressing assembly, a steam outlet side adjusting assembly, and a length adjusting assembly. The steam outlet side locking assembly is disposed inside the base, with one end cooperating with the base and the other end cooperating with the steam outlet side adjusting assembly, which is located between the steam outlet side locking assembly and the moving blade. The radial side pressing assembly is disposed on the upper end of the base, with one end cooperating with the base and the other end cooperating with the moving blade root and the inner radial surface of the blade crown. The length adjusting assembly is located between the base and the end face of the moving blade crown.

[0006] Compared with the prior art, the present invention has the following advantages: By integrating five core components—the base, the steam outlet side locking assembly, the radial side clamping assembly, the steam outlet side adjustment assembly, and the length adjustment assembly—a unified structure with three-dimensional positioning, bidirectional clamping, and dual-dimensional adjustment is formed, solving the industry pain point of poor versatility in traditional tooling. Traditionally, when machining blade roots with strength structures such as fork-shaped steps, separate dedicated tooling needs to be designed for different specifications of moving blades. This not only occupies a large amount of storage space but also requires repeated tooling adjustments, resulting in extremely low adaptation efficiency. In contrast, this invention, through the modular design of the steam outlet side adjustment assembly and the length adjustment assembly, allows for flexible adjustment of assembly specifications according to the blade root, blade crown size, and the total length of the moving blade, eliminating the need to replace the entire tooling set and reducing the design and manufacturing costs of dedicated tooling.

[0007] Furthermore, the bottom inner surface of the base is a radial positioning surface, the right inner surface is an inlet side positioning surface, and the rear inner surface is a blade tip positioning surface. This forms a contour-following, orthogonally constrained positioning system, ensuring a unique positioning datum, improving datum accuracy, and providing clear assembly guidance and significantly enhanced fit.

[0008] Furthermore, both the steam outlet side adjustment assembly and the length adjustment assembly include adjustment shims, and adjustment is achieved by changing the number of adjustment shims. This modular adjustment design reduces operating costs and provides controllable adjustment precision.

[0009] Furthermore, the steam outlet side locking assembly includes a lower push block and left and right push blocks disposed on both sides of the lower push block. The lower push block can push the left and right push blocks to separate to both sides under downward pressure, causing the right push block to move horizontally towards the moving blade, thereby clamping the moving blade between the steam outlet side adjusting assembly and the steam inlet side positioning surface of the base. Through the combined structure and the clamping logic of unilateral tightening and positioning surface constraint, the problems of short clamping arm and easy loosening of traditional single screw clamping are solved.

[0010] Furthermore, the lower push block is inverted trapezoidal, with symmetrical T-shaped protrusions on its left and right sides; the left and right push blocks are both trapezoidal, and each of the left and right push blocks has a T-shaped groove on the side facing the lower push block that slides in conjunction with the T-shaped protrusions. The T-shaped groove structure provides a rigid fit connection, solving the problems of easy detachment and movement jamming of traditional push blocks.

[0011] Furthermore, the push block has a threaded hole in its center, and a pressing screw passes through the threaded hole. The end of the pressing screw is threadedly connected to the mounting hole on the base. The pressing screw provides downward pressure, and the screw is threaded to the base, allowing for a single person to complete the tightening operation, and the connection strength is controllable.

[0012] Furthermore, the radial side clamping assembly includes a clamping block and a clamping screw. The clamping block is inverted U-shaped, with the clamping screw at its upper end. The end of the clamping screw passes through the clamping block and is threadedly connected to a mounting hole on the base. The height of the clamping screw can be adjusted via the thread to accommodate blades with different inner radial surface heights.

[0013] Furthermore, the contact surface between the pressure block and the moving blade is an arc-shaped surface. The arc-shaped surface can disperse stress and prevent indentations or plastic deformation from forming on the blade surface.

[0014] A method for machining the root of a fork-shaped regulating stage moving blade, using the aforementioned fork-shaped regulating stage moving blade root machining fixture for auxiliary machining, includes the following steps: Step 1: Pre-treat the moving blades to provide a positioning reference for the precision machining of the blade root fork groove; Step 2: Place the base on the working platform of the machining tool and calibrate the rear radial positioning surface and the steam inlet side positioning surface of the base to make them precisely aligned with the motion axis of the machine tool, controlling the error to ≤0.03mm. After calibration, clamp and fix the base with a pressure plate or vise. Step 3: Adjust the number of adjustment pads for the steam outlet side adjustment assembly and length adjustment assembly according to the specifications of the moving blade. Place the moving blade on the base and use the three positioning surfaces on the base to position and match the radial surface of the blade root and crown, the steam inlet side end face of the blade root and crown, and the end face of the crown. Step 4: Tighten the pressing screw to move the right push block horizontally towards the moving blade, thereby clamping the moving blade between the steam outlet side adjustment assembly and the steam inlet side positioning surface of the base; Step 5: Tighten the clamping screws to make the end face of one side wall of the U-shaped clamping block in close contact with the inner radial surface of the moving blade, thereby clamping the moving blade in the radial direction. Step 6: Install a carbide rough milling cutter on the machine tool and control the runout of the cutter shank to be less than or equal to 0.02 mm. Use the blade root rough milling cutter to rough machine the blade root. Leave a 0.2 mm allowance on one side of the side and bottom of the blade root fork groove of the moving blade. Step 7: Install a carbide semi-finish milling cutter on the machining tool, use a heavy-duty milling cutter shank, and control the runout of the cutter shank to ≤0.01mm. Use a blade root semi-finish milling cutter to perform semi-finish machining on the blade root. Leave a 0.05mm allowance on one side of the fork groove of the moving blade root, and machine the bottom to the required dimensions. Step 8: Install carbide precision milling cutters on the machining tool, using spinning or hydraulic tool holders, and control the runout of the tool holder to ≤0.003mm. Use a blade root precision milling cutter to finish the blade root and machine the side to the required dimensions. Step 9: Remove the moving blade with the machined root groove from the machine tool and continue processing the subsequent blades.

[0015] The machining process adopts a tooling positioning-stage milling-precision control approach, which forms a synergistic optimization of tooling and methods, improves machining accuracy, and reduces tool wear.

[0016] Furthermore, the pre-processing of the moving blade involves performing five-axis integrated milling to finish the blade profile, inlet and outlet sides, and radial surface, followed by milling the overall blade length. This minimizes the reference error and provides a high-precision reference for the machining of the blade root fork groove. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the main structure of an embodiment of the present invention; Figure 2 This is a top view of the structure according to an embodiment of the present invention; Figure 3 This is an exploded view of the steam outlet side locking assembly according to an embodiment of the present invention; The attached diagram lists the components represented by each number as follows: 1. Base; 11. Radial positioning surface; 12. Inlet side positioning surface; 13. Blade crown end face positioning surface; 2. Outlet side locking assembly; 21. Push block; 22. Left push block; 23. Right push block; 24. Pressing screw; 3. Outlet side adjusting assembly; 4. Radial side pressing assembly; 41. Pressing block; 42. Pressing screw; 5. Moving blade; 6. Length adjusting assembly. Detailed Implementation

[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0020] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this technology based on the specific circumstances.

[0021] In the description of this application, spatial relation terms such as "below," "under," "below," "below," "above," "over," etc., are used herein to describe the relationship between one element or feature shown in the figures and other elements or features. It should be understood that, in addition to the orientation shown in the figures, spatial relation terms also include different orientations of the device in use and operation. For example, if the device in the figures is flipped, an element or feature described as "below" or "under" or "below" of other elements or features will be oriented "above" other elements or features. Therefore, the exemplary terms "below" and "under" can include both upper and lower orientations. Furthermore, the device may also include other orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptive terms used herein are interpreted accordingly.

[0022] In the description of this application, the term "for example" is used to mean "used as an example, illustration, or description." Any embodiment described as "for example" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to make and use the invention. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that the invention can be made without using these specific details. In other instances, well-known structures and processes will not be described in detail to avoid obscuring the description of the invention with unnecessary detail. Therefore, the invention is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed in this application.

[0023] Example 1 like Figures 1 to 3As shown, this embodiment provides a fork-shaped adjusting stage moving blade root machining fixture, including a base 1, a steam outlet side locking assembly 2, a radial side pressing assembly 4, a steam outlet side adjusting assembly 3, and a length adjusting assembly 6. The steam outlet side locking assembly 2 is disposed inside the base 1, with one end cooperating with the base 1 and the other end cooperating with the steam outlet side adjusting assembly 3. The steam outlet side adjusting assembly 3 is disposed between the steam outlet side locking assembly 2 and the moving blade 5. The radial side pressing assembly 4 is disposed on the upper end of the base 1, with one end cooperating with the base 1 and the other end cooperating with the root and inner radial surface of the blade crown of the moving blade 5. The length adjusting assembly 6 is disposed between the base 1 and the end face of the blade crown of the moving blade 5. This embodiment aims to: by integrating five core components—the base 1, the steam outlet side locking assembly 2, the radial side pressing assembly 4, the steam outlet side adjusting assembly 3, and the length adjusting assembly 6—to form an integrated structure with three-dimensional positioning, bidirectional clamping, and dual-dimensional adjustment, thus solving the technical problem of poor versatility of traditional tooling.

[0024] Specifically: The bottom inner surface of the base 1 is the radial back surface positioning surface 11, the right inner surface is the steam inlet side positioning surface 12, and the rear inner surface is the blade crown end face positioning surface 13. These three positioning surfaces correspond to the key references of the blade's radial back surface, steam inlet side, and blade crown end face, respectively, avoiding positioning errors caused by overlapping references in traditional positioning and improving positioning accuracy. The clearly defined positioning surface positions provide operators with intuitive assembly guidance, allowing for quick alignment of the blade through three-sided contact during placement, thus shortening positioning time. Traditional tooling often uses a single clamping method, which is prone to blade root deformation due to uneven force, and the single positioning reference often results in machining errors exceeding 0.05mm. This embodiment achieves multi-dimensional precise positioning of the blade root radial back surface, blade crown radial back surface, and steam inlet side through the three positioning reference surfaces set on the base 1. Combined with the synergistic action of the steam outlet side locking component 2 and the radial side pressing component 4, a triple structure of positioning-locking-pressing is formed, improving clamping accuracy and preventing clamping deformation.

[0025] Both the steam outlet side adjustment component 3 and the length adjustment component 6 include adjustment shims, and adjustment is achieved by changing the number of adjustment shims. The steam outlet side adjustment component 3 can be configured with relevant component dimensions according to the blade root and blade crown, and the length adjustment component 6 can be configured with relevant component dimensions according to the total length of the moving blade 5. The adjustment shims can adopt a standardized size design, with manufacturing costs far lower than customized tooling, and can be replaced individually after wear, avoiding the waste of traditional tooling being scrapped entirely; moreover, step-by-step precise adjustment can be achieved by increasing or decreasing the number of shims, with high adjustment accuracy, which can meet the size compensation requirements of different blade specifications; at the same time, only 3-5 types of standardized shims need to be stocked to cover most blade specifications, replacing the inventory of dozens of sets of traditional customized tooling, with less inventory space occupied.

[0026] The steam outlet side locking assembly 2 includes a lower push block 21 and a left push block 22 and a right push block 23 disposed on both sides of the lower push block 21. The lower push block 21 can push the left and right push blocks 23 to separate to both sides under the action of downward pressure, so that the right push block 23 moves horizontally in the direction of the moving blade 5, thereby clamping the moving blade 5 between the steam outlet side adjusting assembly 3 and the steam inlet side positioning surface 12 of the base 1. When the blade root rigidity of the moving blade 5 of the fork-type steam turbine regulating stage is good (for example, when the blade root single fork thickness to length ratio is 1:4), this assembly is used to position and clamp the moving blade 5. If the blade root rigidity of the moving blade 5 of the fork-type steam turbine regulating stage is weak (for example, when the blade root single fork thickness to length ratio is 1:8), this assembly only provides positioning and locking of the moving blade 5 on the steam inlet and outlet sides. At this time, the radial side clamping assembly 4 is mainly used for clamping. The wedge-shaped structure of the lower push block 21 converts the axial force of the lower screw 24 into the horizontal force of the left and right push blocks, amplifying the clamping force several times to ensure that the moving blade 5 has no displacement under the action of cutting force; and the right push block 23 indirectly contacts the blade through the steam outlet side adjustment component 3, which can compensate for the dimensional deviation of the blade on the steam outlet side by the number of pads, avoiding over-clamping deformation caused by traditional rigid clamping; at the same time, the clamping force is transmitted through the push block rather than acting directly on the blade, avoiding surface damage to the moving blade 5 caused by direct screw tightening.

[0027] In this embodiment, the lower push block 21 is inverted trapezoidal, with T-shaped bosses symmetrically arranged on its left and right sides; the left push block 22 and the right push block 23 are both regular trapezoidal, and each of the left and right push blocks 23 has a T-shaped groove on the side facing the lower push block 21 that slides in conjunction with the T-shaped bosses. The cooperation between the T-shaped bosses and the T-shaped grooves forms a bidirectional uniform constraint in both vertical and horizontal directions, resulting in high horizontal movement accuracy of the push blocks and avoiding lateral offset as is common in traditional rectangular fits; at the same time, the T-shaped structure design prevents the push blocks from disengaging during movement, solving the problem of easy detachment of traditional flat key fits under vibration conditions.

[0028] In this embodiment, the push block 21 has a threaded hole in the center, and a pressing screw 24 passes through the threaded hole. The end of the pressing screw 24 is threadedly connected to the mounting hole on the base 1. The pressing screw 24 provides downward pressure, and the pressing screw 24 is threadedly connected to the base 1. The connection strength is controllable, and the screwing operation can be completed by a single person, making disassembly and replacement convenient.

[0029] The radial side clamping assembly 4 includes a clamping block 41 and a clamping screw 42. The clamping block 41 is arranged in an inverted U-shape, and the clamping screw 42 is provided at its upper end. The end of the clamping screw 42 passes through the clamping block 41 and is threadedly connected to the mounting connection hole on the base 1. The radial side clamping assembly 4 can flexibly switch its usage state according to the difference in blade root rigidity: when the blade root rigidity of the fork-type steam turbine regulating stage moving blade 5 is good, it can be disassembled and not used; when the blade root rigidity of the fork-type steam turbine regulating stage moving blade 5 is weak, the clamping block 41 can be used to apply balanced pressure to the inner radial side of the blade root and blade crown. The inverted U-shaped structure can simultaneously cover the inner radial surfaces of the blade root and the blade crown, forming two-point clamping. The clamping force is more evenly distributed, avoiding the local deformation of the blade caused by traditional single-point clamping. Furthermore, the opening design of the inverted U-shaped clamping block 41 provides ample space for the loading and unloading of blades. Operators can quickly pick up and put down blades by hoisting or manually, improving loading and unloading efficiency. At the same time, the height of the clamping screw 42 can be adjusted by the thread to accommodate blades with different inner radial surface heights, further expanding the applicability range of the tooling.

[0030] In this embodiment, the contact surface between the pressure block 41 and the moving blade 5 is an arc-shaped surface. The arc-shaped surface has a large contact area with the inner radial surface of the blade, reducing contact stress and avoiding indentations or plastic deformation on the blade surface; moreover, the curvature of the arc-shaped surface is perfectly matched with the inner radial surface of the blade, forming a surface contact rather than a traditional line contact, thus improving the stability of radial pressing.

[0031] Example 2 This embodiment provides a method for machining the root of a fork-shaped regulating stage moving blade. The method utilizes the fork-shaped regulating stage moving blade root machining fixture described in Embodiment 1 for auxiliary machining. The method includes the following steps: Step 1: Pre-process the moving blade 5 by performing five-axis integrated milling to finish the blade profile, inlet and outlet sides, and radial surface, and then mill the total length of the blade. Minimize the reference error to provide a high-precision reference for the machining of the blade root fork groove; Step 2: Place the base 1 on the working platform of the machine tool, and calibrate the rear radial positioning surface 11 and the steam inlet side positioning surface 12 of the base 1 so that they are precisely aligned with the motion axis of the machine tool, with the error controlled to be ≤0.03mm. After calibration, fix the base by clamping the two sides in the length direction of the base with a pressure plate or vise. Step 3: Adjust the number of adjusting pads of the steam outlet side adjusting component 3 and the length adjusting component 6 according to the specifications of the moving blade 5. Place the moving blade 5 on the base 1, and use the three positioning surfaces on the base 1 to position and match the radial surface of the blade root and crown, the steam inlet side end face of the blade root and crown, and the end face of the crown of the moving blade 5 respectively. Step 4: Tighten the pressing screw 24 to move the right push block 23 horizontally toward the moving blade 5, thereby clamping the moving blade 5 between the steam outlet side adjustment assembly 3 and the steam inlet side positioning surface 12 of the base 1. Step 5: Tighten the clamping screw 42 to make the U-shaped side wall end face of the pressure block 41 in close contact with the inner radial surface of the moving blade 5, and clamp the moving blade 5 in the radial side orientation. Step 6: Install a carbide rough milling cutter on the machining tool and control the runout of the cutter shank to be less than or equal to 0.02mm. Use the blade root rough milling cutter to rough machine the blade root. Leave a 0.2mm allowance on one side of the side and bottom of the blade root fork groove of the moving blade. Step 7: Install a carbide semi-finish milling cutter on the machining tool, use a heavy-duty milling cutter shank, and control the runout of the cutter shank to ≤0.01mm. Use a blade root semi-finish milling cutter to perform semi-finish machining on the blade root. Leave a 0.05mm allowance on one side of the side of the blade root fork groove of the moving blade, and machine the bottom to the size. Step 8: Install carbide precision milling cutters on the machining tool, using spinning or hydraulic tool holders, and control the runout of the tool holder to ≤0.003mm. Use a blade root precision milling cutter to finish the blade root and machine the side to the required dimensions. Step 9: Remove the moving blade 5 with the processed blade root groove from the machine tool and continue processing the subsequent blades.

[0032] This embodiment adopts a machining process of tooling positioning, staged milling, and precision control, forming a synergistic optimization of tooling and method, improving machining accuracy, and reducing tool wear and machining cycle time. Traditional machining schemes require frequent tool changes to compensate for errors due to insufficient tooling positioning accuracy, and roughing and finishing require the use of multiple sets of tools of different specifications, resulting in high tool wear rates. This embodiment utilizes precise tooling positioning and a tiered machining process, enabling efficient adaptation of solid carbide tools for roughing, semi-finishing, and finishing: 1. Through staged machining—rough milling (0.2mm allowance), semi-finishing milling (0.05mm allowance), and finish milling (to size)—cutting stress is gradually eliminated, reducing the side slope tolerance of the blade root fork groove, improving the dimensional compliance rate, and ensuring reasonable allowance to avoid tool overload; 2. Tool types are matched according to the needs of different machining stages (carbide tools for rough milling and high-precision tools for finish milling), and tool shank runout is controlled (rough milling ≤0.02mm, semi-finishing ≤0.01mm, finish milling ≤0.003mm), increasing tool life and reducing machining costs; 3. Clearly defined operating procedures for each step (such as tooling correction error ≤0.03mm, clamping sequence, etc.) avoid the problem of relying on operator experience in traditional machining, reducing the consistency error of blade dimensions processed by different operators.

[0033] While embodiments or examples of this disclosure have been described with reference to the accompanying drawings, it should be understood that the above embodiments are merely exemplary embodiments or examples, and the scope of the invention is not limited by these embodiments or examples, but only by the granted claims and their equivalents. Various elements in the embodiments or examples may be omitted or replaced by their equivalents. Furthermore, the steps may be performed in a different order than that described in this disclosure. Further, various elements in the embodiments or examples may be combined in various ways. Importantly, as the technology evolves, many elements described herein can be replaced by equivalents that appear after this disclosure.

Claims

1. A tooling for machining the root of a fork-shaped adjusting stage moving blade, characterized in that, Includes a base, a steam outlet side locking assembly, a radial side pressing assembly, a steam outlet side adjusting assembly, and a length adjusting assembly; The steam outlet side locking assembly is located inside the base, with one end cooperating with the base and the other end cooperating with the steam outlet side adjusting assembly. The steam outlet side adjusting assembly is located between the steam outlet side locking assembly and the moving blade. The radial side clamping assembly is located on the upper end of the base, with one end engaging with the base and the other end engaging with the inner radial surface of the blade root and crown. The length adjustment component is disposed between the base and the end face of the moving blade crown.

2. The tooling for machining the root of a fork-shaped adjusting stage moving blade according to claim 1, characterized in that, The bottom inner surface of the base is the rear radial positioning surface, the right side inner surface is the steam inlet side positioning surface, and the rear side inner surface is the blade crown end face positioning surface.

3. The tooling for machining the root of a fork-shaped adjusting stage moving blade according to claim 1, characterized in that, Both the steam outlet side adjustment assembly and the length adjustment assembly include adjustment shims, and adjustment is achieved by changing the number of adjustment shims.

4. The tooling for machining the root of a fork-shaped adjusting stage moving blade according to claim 1, characterized in that, The steam outlet side locking assembly includes a push block and a left push block and a right push block disposed on both sides of the push block. The push block can push the left and right push blocks to separate to both sides under the action of downward pressure, so that the right push block moves horizontally in the direction of the moving blade, thereby clamping the moving blade between the steam outlet side adjusting assembly and the base steam inlet side positioning surface.

5. The tooling for machining the root of a fork-shaped adjusting stage moving blade according to claim 4, characterized in that, The push block is in the shape of an inverted trapezoid, with T-shaped protrusions symmetrically arranged on its left and right sides; the left push block and the right push block are both in the shape of a regular trapezoid, and the side of the left and right push blocks facing the push block is provided with a T-shaped groove that slides in conjunction with the T-shaped protrusion.

6. A tooling for machining the root of a fork-shaped adjusting stage moving blade according to claim 4 or 5, characterized in that, The push block has a threaded hole in the center, and a pressing screw passes through the threaded hole. The end of the pressing screw is threaded to the mounting connection hole on the base.

7. The tooling for machining the root of a fork-shaped adjusting stage moving blade according to claim 1, characterized in that, The radial side clamping assembly includes a clamping block and a clamping screw. The clamping block is arranged in an inverted U-shape, and a clamping screw is provided at its upper end. The end of the clamping screw passes through the clamping block and is threadedly connected to the mounting connection hole on the base.

8. The tooling for machining the root of a fork-shaped adjusting stage moving blade according to claim 7, characterized in that, The contact surface between the pressure block and the moving blade is an arc-shaped surface.

9. A method for machining the root of a fork-shaped regulating stage moving blade, characterized in that, The auxiliary machining of the fork-shaped regulating stage moving blade root machining tooling as described in any one of claims 1 to 8 includes the following steps: Step 1: Pre-treat the moving blades to provide a positioning reference for the precision machining of the blade root fork groove; Step 2: Place the base on the working platform of the machining tool and calibrate the rear radial positioning surface and the steam inlet side positioning surface of the base to make them precisely aligned with the motion axis of the machine tool, controlling the error to ≤0.03mm. After calibration, clamp and fix the base with a pressure plate or vise. Step 3: Adjust the number of adjustment pads for the steam outlet side adjustment assembly and length adjustment assembly according to the specifications of the moving blade. Place the moving blade on the base and use the three positioning surfaces on the base to position and match the radial surface of the blade root and crown, the steam inlet side end face of the blade root and crown, and the end face of the crown. Step 4: Tighten the pressing screw to move the right push block horizontally towards the moving blade, thereby clamping the moving blade between the steam outlet side adjustment assembly and the steam inlet side positioning surface of the base; Step 5: Tighten the clamping screws to make the end face of one side wall of the U-shaped clamping block in close contact with the inner radial surface of the moving blade, thereby clamping the moving blade in the radial direction. Step 6: Install a carbide rough milling cutter on the machine tool and control the runout of the cutter shank to be less than or equal to 0.02 mm. Use the blade root rough milling cutter to rough machine the blade root. Leave a 0.2 mm allowance on one side of the side and bottom of the blade root fork groove of the moving blade. Step 7: Install a carbide semi-finish milling cutter on the machining tool, use a heavy-duty milling cutter shank, and control the runout of the cutter shank to ≤0.01mm. Use a blade root semi-finish milling cutter to perform semi-finish machining on the blade root. Leave a 0.05mm allowance on one side of the fork groove of the moving blade root, and machine the bottom to the required dimensions. Step 8: Install carbide precision milling cutters on the machining tool, using spinning or hydraulic tool holders, and control the runout of the tool holder to ≤0.003mm. Use a blade root precision milling cutter to finish the blade root and machine the side to the required dimensions. Step 9: Remove the moving blade with the machined root groove from the machine tool and continue processing the subsequent blades.

10. A method for processing the root of a fork-shaped regulating stage moving blade according to claim 9, characterized in that, The pretreatment of the moving blade is as follows: perform five-axis integrated milling on the moving blade to finish the blade profile, inlet and outlet sides, and radial surface, and then mill the total length of the blade.

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