Machining tool and machining method for turbine rotor assembly conic long hole machining

Abstract

The application discloses a machining tool and machining method for processing a conical long hole of a turbine rotor assembly. The machining tool comprises a tool base, a tool mandrel, a pressing mechanism and a circumferential positioning mechanism. The tool mandrel is arranged vertically on the tool base. The turbine rotor assembly is sequentially assembled on the tool base, and the tool mandrel sequentially passes through turbine disks of each stage and is arranged on a turbine shaft. The pressing mechanism is connected with the end of the tool mandrel to press the turbine rotor assembly on the tool base. The tool mandrel is sequentially provided with a matching surface corresponding to the axial position of each turbine disk. Each matching surface is matched with the disk core of the corresponding turbine disk. Each matching surface and the disk core of the corresponding turbine disk have a positioning gap. Each positioning gap is used to make the position degree between the blank holes of the corresponding circumferential positions of each turbine disk after circumferential positioning less than or equal to a preset value. The circumferential positioning mechanism is used to circumferentially position the turbine disks of each stage of the turbine rotor assembly assembled on the tool base.

Description

Technical Field

[0001] This invention relates to the field of aero-engine technology, and in particular, to a machining fixture for machining tapered holes in turbine rotor assemblies. Furthermore, this invention also relates to a machining method comprising the aforementioned machining fixture for machining tapered holes in turbine rotor assemblies. Background Technology

[0002] Aero engines are assembled from thousands of parts, and the assembly process demands high precision in the positional and dimensional accuracy of these components. Taking a turbine rotor assembly as an example, this assembly uses a tapered bolt connection structure. Ten tapered bolts, evenly distributed around the circumference, are used to connect and secure each individual component. The turbine shaft, first-stage turbine disk, second-stage turbine disk, and third-stage turbine disk require ten tapered blank holes, each with a taper of 1:48, machined evenly around the circumference. During turbine rotor assembly, the ten tapered bolts are sequentially inserted into the ten tapered blank holes in the turbine shaft, first-stage turbine disk, second-stage turbine disk, and third-stage turbine disk. The outer diameter of the tapered bolt fits snugly against the inner wall of the tapered blank hole. Finally, the nuts that mate with the tapered bolts are tightened, completing the turbine rotor assembly.

[0003] refer to Figure 1 and Figure 2 The method for machining 10 conical blank holes for the turbine shaft, first-stage turbine disk, second-stage turbine disk, and third-stage turbine disk of a type of aero-engine turbine rotor assembly is as follows: 10 conical blank holes are machined individually for each turbine shaft, first-stage turbine disk, second-stage turbine disk, and third-stage turbine disk, evenly distributed along the circumference. Then, the turbine shaft, first-stage turbine disk, second-stage turbine disk, and third-stage turbine disk are sequentially inserted into the conical blank holes and tightened to complete the assembly of the turbine rotor assembly.

[0004] Existing machining technology has the following drawbacks: the positional accuracy of the 10 corresponding conical blank holes for each individual component of the turbine rotor assembly—the turbine shaft, the first-stage turbine disk, the second-stage turbine disk, and the third-stage turbine disk—must be ≤0.16mm, making machining difficult to guarantee. When assembling the conical bolts, if the positional error between the corresponding conical blank holes of one component and another is large (positional accuracy >0.16mm), refer to... Figure 3 The tapered bolts could not be inserted into the tapered blank holes of all the individual parts in sequence, and ultimately the individual parts could not be assembled into a turbine rotor assembly. Summary of the Invention

[0005] This invention provides a machining fixture and machining method for machining tapered holes in turbine rotor assemblies, in order to solve the technical problems of high difficulty in positional control, high machining requirements and low efficiency in machining tapered holes of multi-stage turbine disks in the prior art.

[0006] According to one aspect of the present invention, a machining fixture is provided for machining tapered elongated holes in a turbine rotor assembly. The turbine rotor assembly includes a turbine shaft and turbine disks of stages 1 to N. The turbine disks of stages 1 to N have a number of tapered elongated holes evenly distributed circumferentially. The machining fixture includes a fixture base, a fixture mandrel, a clamping mechanism, and a circumferential positioning mechanism. The fixture mandrel is vertically disposed on the fixture base. The turbine rotor assembly is used to sequentially assemble itself on the fixture base and to allow the fixture mandrel to sequentially pass through each stage of turbine disks and pass through the turbine shaft. The clamping mechanism... The tooling mandrel is used to connect to the end of the tooling mandrel to press the turbine rotor assembly onto the tooling base; the tooling mandrel is constructed with mating surfaces sequentially corresponding to the axial positions of each turbine disk, and each mating surface is used to mate with the disk center of the corresponding turbine disk; each mating surface and the disk center of the corresponding turbine disk have a positioning gap, and each positioning gap is used to ensure that the positional degree between the blank holes at the corresponding circumferential positions of each turbine disk after circumferential positioning is less than or equal to a preset value; the circumferential positioning mechanism is used to perform circumferential positioning of each turbine disk of the turbine rotor assembly assembled on the tooling base.

[0007] As a further improvement to the above technical solution, the circumferential positioning mechanism includes a first guide disk for being disposed above the first-stage turbine disk, the center of the first guide disk being radially positioned and engaged with the outer wall of the turbine shaft; the first guide disk is provided with a first guide hole that matches the position of the blank hole of the first-stage turbine disk, and the circumferential positioning mechanism also includes a first positioning rod for being inserted through the first guide hole into the blank hole at the corresponding circumferential position.

[0008] As a further improvement to the above technical solution, the circumferential positioning mechanism includes a plurality of first positioning rods, each first positioning rod having a first positioning structure. The first positioning structure on each first positioning rod increases progressively or skips levels according to the number of turbine disks. The first positioning structure on the first positioning rod is used to cooperate with the first guide hole or the blank hole.

[0009] As a further improvement to the above technical solution, the circumferential positioning mechanism further includes a second guide disk disposed on the tooling mandrel. The center of the second guide disk is radially positioned and engaged with the outer wall of the tooling mandrel. The second guide disk is provided with a second guide hole that matches the circumferential position of the first guide hole.

[0010] As a further improvement to the above technical solution, the first guide hole is fitted with a positioning bushing, and at least one of the second guide holes is fitted with a positioning bushing.

[0011] As a further improvement to the above technical solution, the first positioning structure has a fitting clearance with the blank hole, and the fitting clearance level is less than or equal to the preset value.

[0012] As a further improvement to the above technical solution, the circumferential positioning mechanism further includes a plurality of second positioning rods. The second positioning rods have second positioning structures. The axial distribution positions of the second positioning structures on each second positioning rod match the axial distribution positions of the first guide hole and each of the turbine disks. The second positioning structures on the second positioning rods are used to cooperate with the first guide hole and each of the machined tapered holes.

[0013] As a further improvement to the above technical solution, the positioning gap is determined based on equations (1) to (3):

[0014] Y = n × {(X0 + X1 + ... + X} n )-(H0+H1+…+H n )} (1)

[0015] P n =H n / H0+H1+…+H n (2)

[0016] X n =P n ×(X0+X1+…+X n (3)

[0017] In the formula, Y is the positional dimension of the tapered bore; N is the number of turbine disk stages, with stage 0 being the turbine shaft; X n H is the positioning clearance value of the inner hole of the turbine disk corresponding to the stage of the tooling mandrel; n P represents the tolerance value of the turbine disk inner bore ΦB for the corresponding grade; n This represents the percentage of the turbine disk bore tolerance value for a given grade as a sum of all turbine disk bore tolerance values.

[0018] According to another aspect of the present invention, a machining method is also provided, comprising the machining fixture described above for machining the tapered elongated hole of a turbine rotor assembly, the machining method comprising:

[0019] S1. Design the dimensions of the first mating surface to the Nth mating surface of the tooling mandrel based on the positional requirements of the tapered bore and the actual value of the inner bore of the turbine rotor assembly;

[0020] S2. Machining the tooling mandrel and assembling it onto the tooling base;

[0021] S3. Sequentially assemble the Nth-stage turbine disk to the first-stage turbine disk onto the tooling base and pass the tooling mandrel through each turbine disk. Assemble the turbine shaft so that the outer end of the tooling mandrel passes through the turbine shaft.

[0022] S4. The circumferential positioning mechanism adjusts each stage of the turbine disk to circumferentially align each blank hole;

[0023] S5. The turbine rotor assembly is pressed onto the tooling base by the clamping mechanism;

[0024] S6. In the combined assembly state, the blank holes at the same circumferential position on each level of turbine disk are machined by a single feed of the tool;

[0025] S7. Complete the machining of blank holes in each circumferential position in sequence.

[0026] As a further improvement to the above technical solution, step S4 includes:

[0027] S41. Make rough adjustment of the circumferential position of each stage of turbine disk, insert the first positioning rod, which is provided with the first positioning structure only corresponding to the first guide hole, into the first guide hole and pass through the blank hole of each stage of turbine disk in sequence;

[0028] S42. Adjust the circumferential position of each stage of turbine disks, insert the first positioning rod, which is provided with the first positioning structure only for the first guide hole and the first stage turbine disk, into the first guide hole and pass through the blank holes of each stage of turbine disks in sequence;

[0029] S43. Insert the first positioning rods with the corresponding number of first positioning structures according to the number of stages, and adjust the circumferential position of each stage of turbine disk.

[0030] The present invention has the following beneficial effects:

[0031] This machining fixture uses a mandrel with multiple mating surfaces to match each turbine disk. After each turbine disk is sequentially installed into the mandrel, it achieves precise positioning by precisely fitting the mating surfaces corresponding to the axial positions with small clearances. A circumferential positioning mechanism performs circumferential positioning of each stage of the turbine disk in the turbine rotor assembly mounted on the fixture base. The mating surface dimensions of the mandrel are designed based on the known inner hole dimensions of the corresponding turbine disk, ensuring a positioning clearance between them, which is controlled within a certain range. This ensures that the positional accuracy between the blank holes at the corresponding circumferential positions of each turbine disk after circumferential positioning is less than or equal to a preset value. Consequently, the machining tool can machine the blank holes in one pass from top to bottom. By designing the mating surface dimensions of the mandrel based on the known inner hole dimensions of the turbine disk, the positioning clearance can be controlled to control the positional accuracy of the tapered holes. This ensures that the assembled and circumferentially positioned turbine rotor assembly meets the machining requirements without the need to inspect or verify the dimensions of each tapered hole. Furthermore, the machining tool can machine the blank holes at the same circumferential position in one pass, significantly improving machining efficiency and quality, and avoiding losses such as scrapped parts.

[0032] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0033] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0034] Figure 1 This is a schematic diagram of the structure of a turbine rotor assembly in the prior art;

[0035] Figure 2 This is a schematic diagram showing the location distribution of the tapered bolt holes in a turbine rotor assembly in the prior art;

[0036] Figure 3 This is a schematic diagram of a turbine rotor assembly in the prior art when the positional error is too large.

[0037] Figure 4 This is a schematic diagram of the processing tooling structure of a preferred embodiment of the present invention;

[0038] Figure 5 This is a schematic diagram of the assembly and processing of the turbine rotor assembly according to a preferred embodiment of the present invention;

[0039] Figure 6 yes Figure 5 A magnified view of a portion of the image;

[0040] Figure 7 This is a schematic diagram of the single-piece size offset limit of a preferred embodiment of the present invention.

[0041] Legend:

[0042] 1. Turbine shaft; 2. Turbine disc; 201. Blank hole; 3. Tapered bolt; 4. Tooling base; 5. Tooling mandrel; 6. Clamping mechanism; 601. Rod; 602. Force-applying structure; 603. Tooling pressure plate; 7. Circumferential positioning mechanism; 701. First guide plate; 7011. First guide hole; 702. First positioning rod; 7021. First positioning structure; 703. Second positioning rod; 7031. Second positioning structure; 704. Second guide plate; 7041. Second guide hole; 705. Positioning bushing; 706. Support base; 8. Machining tool. Detailed Implementation

[0043] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0044] Figure 1 This is a schematic diagram of the structure of a turbine rotor assembly in the prior art; Figure 2 This is a schematic diagram showing the location distribution of the tapered bolt holes in a turbine rotor assembly in the prior art; Figure 3 This is a schematic diagram of a turbine rotor assembly in the prior art when the positional error is too large. Figure 4This is a schematic diagram of the processing tooling structure of a preferred embodiment of the present invention; Figure 5 This is a schematic diagram of the assembly and processing of the turbine rotor assembly according to a preferred embodiment of the present invention; Figure 6 yes Figure 5 A magnified view of a portion of the image; Figure 7 This is a schematic diagram of the single-piece size offset limit of a preferred embodiment of the present invention.

[0045] like Figures 4 to 7 As shown in this embodiment, the machining fixture for machining the tapered elongated holes of a turbine rotor assembly includes a turbine shaft 1 and turbine disks 2 of stages 1 to N. The first to preset stage turbine disks 2 have a number of tapered elongated holes evenly distributed circumferentially. The machining fixture includes a fixture base 4, a fixture mandrel 5, a clamping mechanism 6, and a circumferential positioning mechanism 7. The fixture mandrel 5 is vertically arranged on the fixture base 4. The turbine rotor assembly is used to sequentially assemble on the fixture base 4 and to allow the fixture mandrel 5 to sequentially pass through each stage of turbine disk 2 and pass through the turbine shaft 1. The clamping mechanism 6 is used to... The end of the tooling mandrel 5 is connected to press the turbine rotor assembly onto the tooling base 4; the tooling mandrel 5 is constructed with mating surfaces in sequence corresponding to the axial positions of each turbine disk 2, and each mating surface is used to mate with the disk center of the corresponding turbine disk 2; each mating surface and the disk center of the corresponding turbine disk 2 have a positioning gap, and each positioning gap is used to make the positional degree between the blank holes 201 at the corresponding circumferential positions of each turbine disk 2 after circumferential positioning less than or equal to a preset value; the circumferential positioning mechanism 7 is used to perform circumferential positioning of each turbine disk 2 of the turbine rotor assembly assembled on the tooling base 4.

[0046] In this embodiment, the turbine rotor assembly has a three-stage turbine disk 2 as an example. The preset value is the positional accuracy requirement of the tapered hole. For example, in some embodiments, the positional accuracy of the tapered hole is required to be ≤0.16mm. The mating surface of the tooling mandrel 5 is provided by its outer wall protruding to facilitate the assembly of the turbine rotor assembly.

[0047] The tooling mandrel 5 has an internal thread at its outer end. The clamping mechanism 6 includes a rod 601 threadedly connected to the tooling mandrel 5, a force-applying structure 602 set on the rod 601, and a tooling pressure plate 603 set on the rod 601. The force-applying structure 602 can be a handle or other structure.

[0048] It should be understood that this machining fixture is used for the final finishing of the tapered holes on each stage of the turbine disk 2 on the turbine rotor assembly. The tapered holes on each stage of the turbine disk 2 are first rough-machined to form cylindrical blank holes 201, leaving a finishing allowance.

[0049] Understandably, this machining fixture uses a multi-stage mating mandrel 5 to match each turbine disk 2. After each turbine disk 2 is sequentially installed into the tooling mandrel 5, it achieves precise positioning by precisely engaging with the mating surfaces corresponding to its axial position with a small clearance. The circumferential positioning mechanism 7 performs circumferential positioning of each stage of the turbine disk 2 assembled on the tooling base 4. The mating surface dimensions of the tooling mandrel 5 are designed based on the known inner hole dimensions of the corresponding turbine disk 2, ensuring a positioning clearance between them, which is controlled within a certain range, so that the corresponding circumferential positions of each turbine disk 2 after circumferential positioning are... The positional tolerance between the blank holes 201 is less than or equal to a preset value, so that the machining tool 8 can process them in one go from top to bottom. Only the dimensions of the tooling mandrel 5 mating surface need to be designed based on the known inner hole size of the turbine disk 2, so that the positioning clearance can be controlled to control the positional tolerance of the tapered holes. This ensures that the turbine rotor assembly after assembly and circumferential positioning meets the processing requirements. There is no need to inspect or verify the dimensions of each tapered hole, and the machining tool 8 can process the blank holes 201 in the same circumferential position in one go, which greatly improves the processing efficiency, improves the processing quality, and avoids losses such as scrapped parts.

[0050] It should be understood that the machining tool 8 in this embodiment was redesigned and manufactured according to the requirement of forming the shape in one machining operation;

[0051] It should be noted that the positioning gap in this embodiment is determined based on equations (1) to (3):

[0052] Y = n × {(X0 + X1 + ... + X} n )-(H0+H1+…+H n )} (1)

[0053] P n =H n / H0+H1+…+H n (2)

[0054] X n =P n ×(X0+X1+…+X n (3)

[0055] In the formula, Y is the positional dimension of the tapered bore; N is the number of turbine disk stages, with stage 0 being the turbine shaft; X n H is the positioning clearance value of the inner hole of the turbine disk corresponding to the stage of the tooling mandrel; n P represents the tolerance value of the turbine disk inner bore ΦB for the corresponding grade; n This represents the percentage of the turbine disk bore tolerance value of a certain corresponding grade as a sum of all turbine disk bore tolerance values;

[0056] As can be seen, after calculating using the above formula, when the positional tolerance Y of the tapered bore is determined, the required X can be calculated based on the actual size of the turbine disk's inner bore and the actual tolerance value of ΦB. n The tooling mandrel corresponds to the positioning clearance value of the inner hole of the turbine disk of each stage. Then, based on each positioning clearance value, the dimensions of each mating surface are matched and machined. This allows the turbine rotor assembly to meet the positioning and positional accuracy requirements after being clamped in this machining fixture, eliminating the need for secondary inspection, improving efficiency and accuracy. Each individual part meets the assembly requirements, realizing the machining method of machining the blank hole from top to bottom in the assembled state, avoiding part scrap and quality loss.

[0057] In some embodiments, the circumferential positioning mechanism 7 includes a first guide disk 701 disposed above the first-stage turbine disk 2, which is connected and supported by a support base 706 installed on one side of the working base; the center of the first guide disk 701 is radially positioned and engaged with the outer wall of the turbine shaft 1; the first guide disk 701 is provided with a first guide hole 7011 that matches the position of the blank hole 201 of the first-stage turbine disk 2; the circumferential positioning mechanism 7 also includes a first positioning rod 702, which is inserted through the first guide hole 7011 to the blank hole 201 at the corresponding circumferential position. The first positioning rod 702 is inserted sequentially into the first guide hole 7011, the blank hole 201 of the first-stage turbine disk 2, the blank hole 201 of the second-stage turbine disk 2, and the blank hole 201 of the third-stage turbine disk 2. During the insertion process, the circumferential position of each stage of the turbine disk 2 is adjusted to achieve circumferential positioning of the turbine rotor assembly. After circumferential positioning, it can be pressed by the clamping mechanism 6, thereby enabling the processing of the blank hole 201;

[0058] Furthermore, the circumferential positioning mechanism 7 includes multiple first positioning rods 702, each having a first positioning structure 7021. The first positioning structures 7021 on each first positioning rod 702 increase sequentially or skip stages according to the number of turbine disks 2. The first positioning structures 7021 on the first positioning rod 702 are used to mate with the first guide hole 7011 or the corresponding blank hole 201. For example, this embodiment provides two specifications of first positioning rods 702. The radial dimension of the rod body of the first positioning rod 702 is smaller than that of the blank hole 201, while the size of the first positioning structure 7021 matches that of the blank hole 201. The first positioning rod 702 of the first specification is provided with the first positioning structure 7021 corresponding to the first guide hole 7011, and is inserted into the first guide hole 7011, the blank hole 201 of the first stage turbine disk 2, and the blank hole 201 of the second stage turbine disk 2. During the process of blanking the blank hole 201 of the third-stage turbine disk 2, the circumferential position of the turbine disk 2 is adjusted so that it can be smoothly inserted. The first positioning rod 702 of the second specification is set with the first positioning structure 7021 corresponding to the positions of the first guide hole 7011, the first-stage turbine disk 2, the second-stage turbine disk 2, and the third-stage turbine disk 2, respectively. After the first positioning rod 702 of the first specification is initially circumferentially positioned, the first positioning rod 702 of the second specification can be inserted to adjust the circumferential position of the turbine disk 2 more smoothly and conveniently, ensuring circumferential positioning. In other embodiments, at least N first positioning rods 702 can also be set, and the first positioning structure 7021 of each first positioning rod 702 increases step by step. During positioning, the first positioning rods 702 can be inserted in sequence to adjust the circumferential position of each stage of the turbine disk 2 in turn, which makes the adjustment easier and the positioning rods are inserted more smoothly.

[0059] It is understandable that the tooling base 4 can be provided with holes corresponding to the circumferential distribution of the tapered holes for the insertion of the first positioning rod 702, so as to avoid the first positioning rod 702 from being misaligned when the fit clearance between the first positioning rod 702 and the blank hole 201 is large, which would make it difficult to insert the first positioning rod 702 in the future.

[0060] It should be noted that, in a specific embodiment, in the actual structure of the turbine rotor assembly, the first-stage turbine disk 2 and the second-stage turbine disk 2 each have 10 circumferentially evenly distributed tapered holes, while the third-stage turbine disk 2 has 5 circumferentially evenly distributed tapered holes; therefore, in this embodiment, the actual number of first positioning rods 702 is ≤5, preferably 4, for example, one first positioning rod 702 of the first specification and three first positioning rods 702 of the second specification, leaving one hole for direct processing. First, the blank hole 201 is processed at the position where tapered holes are distributed in the circumferential direction at each stage.

[0061] Furthermore, the circumferential positioning mechanism 7 includes a plurality of second positioning rods 703, each second positioning rod 703 having a second positioning structure 7031. The axial distribution position of the second positioning structure 7031 on each second positioning rod 703 matches the axial distribution position of the first guide hole 7011 and each of the turbine disks 2. The second positioning structure 7031 on the second positioning rod 703 is used to cooperate with the first guide hole 7011 and with each of the machined tapered holes. It should be understood that each second positioning structure 7031 is matched with the taper and size of the corresponding tapered hole. After the tapered hole in one circumferential position is machined, the second positioning rod 703 is inserted to maintain circumferential positioning. Its positioning function and positioning effect are the same as the first positioning rod 702, ensuring the circumferential positioning accuracy of subsequent hole machining.

[0062] Furthermore, the circumferential positioning mechanism 7 also includes a second guide disk 704 disposed on the tooling mandrel 5. The center of the second guide disk 704 is radially positioned and engaged with the outer wall of the tooling mandrel 5. The second guide disk 704 is provided with a second guide hole 7041 that matches the circumferential position of the first guide hole 7011. The axial position of the second guide disk 704 is set according to the actual structure, preferably in the middle or lower part or in a position with a large axial distance between the turbine disks 2. For example, in this embodiment, it is disposed between the second-stage turbine disk 2 and the third-stage turbine disk 2 to avoid the first positioning rod 702 from swaying when inserted, and to guide its insertion so that it can be inserted more smoothly.

[0063] In some embodiments, the first positioning structure 7021 and the blank hole 201 have a fitting clearance, and the fitting clearance * grade is less than or equal to a preset value. For example, the positional accuracy of the corresponding tapered bolt 3 holes between each individual piece is ≤0.16mm, and the fitting clearance is ≤0.16 / 3mm (e.g., 0.05mm) to ensure the positional accuracy of the corresponding tapered bolt 3 holes.

[0064] Furthermore, a positioning bushing 705 is embedded in the first guide hole 7011. The positioning bushing 705 ensures the dimensional accuracy of the first positioning structure 7021 to guarantee the fitting clearance, making the guide plate universal. The positioning bushing 705 is machined according to the required fitting clearance of different turbine rotor assemblies, resulting in lower cost. Similarly, the positioning bushing 705 is set in the corresponding hole on the tooling base 4. It should be noted that at least one second guide hole 7041 is embedded with a positioning bushing 705, which is suitable for the first positioning rod 702 of the first specification, to prevent swaying during the insertion process, which would cause positioning difficulties.

[0065] On the other hand, a preferred embodiment of the present invention also provides a processing method, which utilizes the above-mentioned machining fixture for machining the tapered elongated hole of a turbine rotor assembly, and the processing method includes:

[0066] S1. Design the dimensions of the first mating surface to the Nth mating surface of the tooling mandrel 5 according to the positional requirements of the tapered hole and the actual value of the inner hole of the turbine rotor assembly;

[0067] S2. Machining tooling mandrel 5 and assembling it onto tooling base 4;

[0068] S3. Sequentially assemble the Nth stage turbine disk 2 to the first stage turbine disk 2 onto the tooling base 4 and pass the tooling mandrel 5 through each turbine disk 2. Assemble the turbine shaft 1 so that the outer end of the tooling mandrel 5 passes through the turbine shaft 1.

[0069] S4. The circumferential positioning mechanism 7 adjusts the turbine disks 2 at each stage to circumferentially align each tapered hole;

[0070] S5. The turbine rotor assembly is pressed onto the tooling base 4 by the clamping mechanism 6;

[0071] S6. In the combined assembly state, the tapered holes at the same circumferential position on each level of turbine disk 2 are machined by a single feed of the tool;

[0072] S7. Complete the machining of tapered holes at each circumferential position in sequence.

[0073] This machining method controls the fit clearance between the first mating surface to the Nth mating surface of the tooling mandrel 5 and each level of turbine disk 2 by controlling the dimensions of the tooling mandrel 5. This controls the position of the blank hole 201 of the tapered elongated hole between each level of turbine disk 2 to meet the machining requirements. In the combined assembly state, the tapered elongated hole at the same circumferential position on each level of turbine disk 2 is machined by the tool in one pass. This greatly improves the machining efficiency and accuracy, reduces the inspection process, and avoids part scrap and quality problems caused by machining errors.

[0074] Furthermore, step S4 includes:

[0075] S41. Make rough adjustment of the circumferential position of each stage of turbine disk 2, insert the first positioning rod 702, which is provided with the first positioning structure 7021 only corresponding to the first guide hole 7011, into the first guide hole 7011 and pass through the blank hole 201 of each stage of turbine disk 2 in sequence;

[0076] S42. Adjust the circumferential position of each stage of turbine disk 2, insert the first positioning rod 702, which is provided with the first positioning structure 7021 only corresponding to the first guide hole 7011 and the first stage turbine disk 2, into the first guide hole 7011 and pass through the blank hole 201 of each stage of turbine disk 2 in sequence;

[0077] S43. Insert the first positioning rods 702 with the corresponding number of first positioning structures 7021 according to the number of stages, and adjust the circumferential position of each stage turbine disk 2.

[0078] According to the number of stages, insert the first positioning rods 702 with the corresponding number of first positioning structures 7021 and adjust the circumferential position of each stage of turbine disk 2 so that the turbine disk 2 is positioned circumferentially from top to bottom, making the adjustment process clearer, avoiding confusion, and making the adjustment smoother.

[0079] Example 1

[0080] In this embodiment, the turbine shaft inner bore is known. First-stage turbine disk inner bore Second-stage scroll inner hole Third-stage turbine disk inner bore The positional tolerance of the 10 tapered bolt holes is ≤0.16mm. Calculate the positioning clearance values ​​X0 between the tooling mandrel ΦA and the inner hole ΦB of the turbine shaft, X1 between the mandrel and the inner hole ΦB of the first-stage turbine disk, X2 between the mandrel and the inner hole ΦB of the second-stage turbine disk, and X3 between the mandrel and the inner hole ΦB of the third-stage turbine disk; Y=0.16, H0=0.02, H1=0.02, H2=0.02, H3=0.02, according to formula (1) Y=n×{(X0+X1+…+X… n )-(H0+H1+…+H n The calculation yields X0 + X1 + X2 + X3 = 0.12 mm; according to formula (2) P n =H n / H0+H1+…+H n We obtain P1 = 0.25, P2 = 0.25, P3 = 0.25, P0 = 0.25, and according to equation (3)X n =P n ×(X0+X1+…+X n The values ​​X0 = 0.03, X1 = 0.03, X2 = 0.03, and X3 = 0.03 are obtained. Calculations show the positioning clearance values ​​X0 = 0.03 mm between the tooling mandrel ΦA and the inner hole ΦB of the turbine shaft, X1 = 0.03 mm between the mandrel and the inner hole ΦB of the first-stage turbine disk, X2 = 0.03 mm between the mandrel and the inner hole ΦB of the second-stage turbine disk, and X3 = 0.03 mm between the mandrel and the inner hole ΦB of the third-stage turbine disk. The outer diameter of the positioning mandrel and turbine shaft is determined based on the hole-shaft clearance fit. With the outer diameter of the first-stage turbine disk With the outer diameter of the second-stage turbine disk With the outer diameter of the third-stage turbine disk It can be guaranteed that the positional dimension of the 10 corresponding tapered bolt holes processed in the combined assembly state of each individual part is ≤0.16mm, and each individual part can meet the combined assembly requirements.

[0081] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0082] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" 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 invention based on the specific circumstances.

[0083] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A machining fixture for machining tapered holes in a turbine rotor assembly, the turbine rotor assembly comprising a turbine shaft (1) and turbine disks (2) of stages 1 to N, wherein the turbine disks (2) of stages 1 to N have a number of tapered holes evenly distributed circumferentially, characterized in that, The machining fixture includes a fixture base (4), a fixture mandrel (5), a clamping mechanism (6), and a circumferential positioning mechanism (7). The fixture mandrel (5) is vertically mounted on the fixture base (4). The turbine rotor assembly is used to sequentially assemble the fixture mandrel (5) on the fixture base (4) and allow the fixture mandrel (5) to sequentially pass through each stage of turbine disks (2) and pass through the turbine shaft (1). The clamping mechanism (6) is used to connect to the end of the fixture mandrel (5) to clamp the turbine rotor assembly onto the fixture base (4). The tooling mandrel (5) is constructed with mating surfaces sequentially corresponding to the axial positions of each turbine disk (2), and each mating surface is used to mate with the disk center of the corresponding turbine disk (2); each mating surface and the disk center of the corresponding turbine disk (2) have a positioning gap, and each positioning gap is used to ensure that the positional degree between the blank holes (201) at the corresponding circumferential positions of each turbine disk (2) after circumferential positioning is less than or equal to a preset value; the circumferential positioning mechanism (7) is used to position the turbine disks (2) of each stage of the turbine rotor assembly assembled on the tooling base (4). Circumferential positioning; the circumferential positioning mechanism (7) includes a first guide disk (701) for being disposed above the first-stage turbine disk (2), the center of the first guide disk (701) being radially positioned with the outer wall of the turbine shaft (1); the first guide disk (701) is provided with a first guide hole (7011) that matches the position of the blank hole (201) of the first-stage turbine disk (2), and the circumferential positioning mechanism (7) also includes a first positioning rod (702) for passing through the first guide hole (7011). The blank hole (201) is positioned at the corresponding circumferential position. The circumferential positioning mechanism (7) includes a plurality of first positioning rods (702). Each first positioning rod (702) has a first positioning structure (7021). The first positioning structure (7021) on each first positioning rod (702) increases or skips steps according to the number of turbine disks (2). The first positioning structure (7021) on the first positioning rod (702) is used to cooperate with the first guide hole (7011) or the blank hole (201).

2. The machining fixture for machining tapered holes in turbine rotor assemblies according to claim 1, characterized in that, The circumferential positioning mechanism (7) further includes a second guide disk (704) disposed on the tooling mandrel (5). The center of the second guide disk (704) is radially positioned and engaged with the outer wall of the tooling mandrel (5). The second guide disk (704) is provided with a second guide hole (7041) that matches the circumferential position of the first guide hole (7011).

3. The machining fixture for machining tapered holes in turbine rotor assemblies according to claim 2, characterized in that, The first guide hole (7011) is fitted with a positioning bushing (705), and at least one second guide hole (7041) is fitted with a positioning bushing (705).

4. The machining fixture for machining tapered holes in turbine rotor assemblies according to claim 1, characterized in that, The first positioning structure (7021) and the blank hole (201) have a fitting clearance. The level is less than or equal to the preset value.

5. The machining fixture for machining tapered holes in turbine rotor assemblies according to claim 1, characterized in that, The circumferential positioning mechanism (7) further includes a plurality of second positioning rods (703), each second positioning rod (703) having a second positioning structure (7031). The axial distribution position of the second positioning structure (7031) on each second positioning rod (703) matches the axial distribution position of the first guide hole (7011) and each turbine disk (2). The second positioning structure (7031) on the second positioning rod (703) is used to cooperate with the first guide hole (7011) and with each tapered hole after machining.

6. The machining fixture for machining tapered holes in turbine rotor assemblies according to any one of claims 1-5, characterized in that, The positioning gap is determined based on equations 1) to 3): 1)； 2)； 3)； In the formula, Y is the positional dimension of the tapered orifice; N is the number of turbine disk stages, and stage 0 is the turbine shaft; This is the positioning clearance value of the inner hole of the turbine disk corresponding to the stage of the tooling mandrel; This represents the tolerance value ΦB of the turbine disk inner bore for the corresponding grade. This represents the percentage of the turbine disk bore tolerance value for a given grade as a sum of all turbine disk bore tolerance values.

7. A processing method, characterized in that, The tooling for machining tapered holes in turbine rotor assemblies as described in claim 6 is used, and the machining method includes: S1. Design the dimensions of the first mating surface to the Nth mating surface of the tooling mandrel based on the positional requirements of the tapered bore and the actual value of the inner bore of the turbine rotor assembly; S2. Machining the tooling mandrel and assembling it onto the tooling base; S3. Sequentially assemble the Nth-stage turbine disk to the first-stage turbine disk onto the tooling base and pass the tooling mandrel through each turbine disk. Assemble the turbine shaft so that the outer end of the tooling mandrel passes through the turbine shaft. S4. The circumferential positioning mechanism adjusts each stage of the turbine disk to circumferentially align each blank hole; S5. The turbine rotor assembly is pressed onto the tooling base by the clamping mechanism; S6. In the combined assembly state, the blank holes at the same circumferential position on each level of turbine disk are machined by a single feed of the tool; S7. Complete the machining of blank holes in each circumferential position in sequence.

8. The processing method according to claim 7, characterized in that, Step S4 includes: S41. Make rough adjustment of the circumferential position of each stage of turbine disk, insert the first positioning rod, which is provided with the first positioning structure only corresponding to the first guide hole, into the first guide hole and pass through the blank hole of each stage of turbine disk in sequence; S42. Adjust the circumferential position of each stage of turbine disks, insert the first positioning rod, which is provided with the first positioning structure only for the first guide hole and the first stage turbine disk, into the first guide hole and pass through the blank holes of each stage of turbine disks in sequence; S43. Insert the first positioning rods with the corresponding number of first positioning structures according to the number of stages, and adjust the circumferential position of each stage of turbine disk.

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