Combined processing tool and repairing method for dovetail type sealing insert pressure surface

Abstract

The dovetail type sealing insert pressure surface combined machining tool provided by the application is suitable for machining of multiple aviation inserts used for sealing of sealing disc spline teeth, and comprises a base, multiple arc-shaped structure arranged push blocks which are distributed at intervals along the outer ring surface of the boss and are provided with protrusions on the outer ring surface, and multiple groups of pushing assemblies which are installed at intervals at the edge position of the top surface of the base and can drive the push blocks to move radially along the base, tightly clamp the inserts in cooperation with the boss, and process the axial side surface of the inserts through the cutter of the lathe, thereby improving the processing efficiency of the inserts.

Description

Technical Field

[0001] This invention belongs to the technical field of aero-engine repair and assembly technology, and particularly relates to a dovetail-shaped sealing insert pressure surface assembly machining tooling and repair method. Background Technology

[0002] A certain powder metallurgy insert has a dovetail structure. More than 80 of these inserts are required for a single aero-engine. These inserts are positioned and assembled in the inner ring groove of the casing via the side (i.e., the pressure surface). The top surface of the insert mates with the teeth of the sealing disc to achieve the air sealing function. Since the manufacturing precision of powder metallurgy cannot directly guarantee the assembly precision, a certain machining allowance (approximately 2mm) is left on the pressure surface of the insert.

[0003] In the existing process, single-piece milling is performed by clamping the insert in a flat-jaw vise on a milling machine, supplemented by manual fitting, to ensure a good fit between the insert and the inner ring groove of the housing. The fit requirement is that the gap should not exceed 0.1mm within a range of 1.5mm. This existing process has the following shortcomings:

[0004] The parts processing and assembly takes more than 10 days, which is inefficient; When milling individual parts, using a straight surface instead of a conical surface for machining results in local interference or gaps when the insert mates with the inner ring groove of the housing, leading to a large amount of repair work. Summary of the Invention

[0005] In view of this, the dovetail-shaped sealing insert pressure surface combination machining tooling of the present invention solves the technical problem of low machining efficiency of existing inserts.

[0006] A dovetail-shaped sealing insert pressure surface assembly machining fixture is applicable to the machining of multiple aerospace inserts, wherein the inserts are used for sealing the teeth of sealing discs, comprising: The base is mounted on the chuck of a lathe. A mounting hole is provided in the middle area. A boss is provided on the top surface of the mounting hole. An annular groove is provided radially on the base and adjacent to the boss. The annular groove is used to place multiple inserts. Multiple push blocks with arc-shaped structures are distributed at intervals along the outer ring surface of the boss, and the outer ring surface is provided with protrusions. Multiple sets of pushing components are installed at intervals along the edge of the top surface of the base, which can drive the push block to move radially along the base. Together with the boss, they can tightly clamp the insert, and the axial side of the insert can be machined by the cutting tool of the lathe.

[0007] Furthermore, a rubber sheet is bonded to the inner ring surface of the pusher block, and the rubber sheet can increase the contact area with the insert when compressed.

[0008] Furthermore, gaps are left between both ends of the push block and its adjacent push blocks. These gaps can accommodate the processing of different types of inserts and can actively adapt to the deformation of the rubber sheet, leaving room for deformation and avoiding mutual interference.

[0009] Furthermore, the pushing assembly includes: a guide plate with a through groove on its bottom surface along the width direction, the through groove being clearance-fitted with the protrusion; and a support plate with lugs, spaced apart from the guide plate along the radial direction of the base, wherein the lugs of the support plate are threaded with clamping screws, one end of the clamping screws being used for external force rotation, and the other end being mounted on the side of the protrusion away from the mounting hole in a free-rotating manner.

[0010] Furthermore, a mating groove is provided on the side of the protrusion away from the mounting hole, and a limiting block is provided at one end of the clamping screw. The limiting block can be inserted into the mating groove to achieve free rotation, and the groove opening size is larger than the size of the limiting block to prevent the limiting block from disengaging from the mating groove. In use, rotating the clamping screw can push the push block radially along the base to clamp or hold the insert.

[0011] Secondly, an insert repair method is provided, using the tooling described above, where one trapezoidal surface of the insert is used as the machined surface and the other trapezoidal surface is used as the non-machined surface. The method includes the following steps. S1: Determine the amount of material removed during processing as ΔT, where, The thickness of the steel strip with pads and the machining dimensions of the top surface of the inserts are selected based on the wear measured by the inserts and the fit requirements between the inserts and the teeth, so as to determine the compensation dimension ΔR. The machining removal amount of the single-sided pressure surface of the insert is determined as ΔT based on the pressure surface angle of the insert and the compensation dimension ΔR. The distance ΔX is the distance the insert slides from its non-machined surface to its machined surface, where it contacts the inner annular groove of the housing. Based on geometric relationships, we have: (1) (2) Combining equations (1) and (2), we can obtain: (3); As can be seen from formula (3), the amount of material removed from the pressure surface of the insert machining surface can be determined as ΔT based on the compensation dimensions of the steel strip with padding. S2: To ensure the symmetry of the insert's dovetail shape, two machining processes are performed. First, the pressure surface of the machined surface is turned, and then the pressure surface of the non-machined surface is turned. S3: After the insert is clamped by the tooling, it is turned according to the machining removal amount ΔT; S4: Steel strip with padding assembly and processing, in which... First, the shaped steel strip is padded and inserted into the inner ring groove of the casing. Then, the insert after removing the amount of material removed by ΔT is inserted to ensure that the two pressure surfaces of the insert are in close contact with the side of the inner ring groove. The entire assembly is mounted on a lathe, and the top surface of the insert is repaired to meet the clearance requirements for mating with the sealing teeth.

[0012] The beneficial effects of the present invention are as follows: The fixture achieves group positioning of multiple inserts through the ring groove and boss structure on the base, and synchronous clamping of the inserts by driving the push block to move radially through multiple sets of push components. This allows for group machining of the pressure surfaces of the inserts on a conventional horizontal lathe, replacing the original single-piece milling and clamping process. This fixture can process over 80 inserts in a group, significantly improving processing efficiency and saving nearly 10 days of processing time. Furthermore, the turning method creates a conical surface that better fits the inner ring groove of the housing, replacing the original planar approximation machining method. This ensures a tight fit between the inserts and the inner ring groove of the housing, significantly improving the assembly quality of the parts.

[0013] An insert repair method has been developed, which realizes the restoration of the insert mating dimensions, solves the problem that the insert wear exceeds the tolerance after service and cannot meet the assembly requirements, and greatly saves the cost of repair and replacement parts. Attached Figure Description

[0014] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a perspective view of the device of the present invention; Figure 2 This is a plan view of the device of the present invention; Figure 3 A schematic diagram for calculating the machining dimensions of the pressure surface of the insert; Among them, 1-base; 11-mounting hole; 12-boob; 2-push block; 21-boob; 4-guide plate; 41-through groove; 7-support plate; 8-clamping screw; 20-insert. Detailed Implementation

[0016] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0017] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0018] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this invention, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using other structures and / or functionalities besides one or more of the aspects set forth herein.

[0019] like Figure 1 and Figure 3 As shown, the base 1 is mounted on the chuck of a lathe (preferably a conventional horizontal lathe). A mounting hole 11 is provided in the central area of ​​the base 1, and a boss 12 is provided on the top surface of the base 1 adjacent to the mounting hole 11. An annular groove is provided radially on the base 1 and adjacent to the boss 12. This annular groove is used for placing multiple inserts 20.

[0020] In one embodiment, the depth and width of the annular groove are designed according to the dimensions of the insert 20, so that the insert 20 can be positioned and installed in the annular groove with its bottom and side (pressure surface) facing up, while the other side to be machined is on top. The base 1 uses the dimensions of the mounting hole 11 as a reference circle for alignment and positioning during tooling machining and installation.

[0021] In addition, lifting eye bolts can be installed on the base 1 to facilitate the hoisting and installation of tooling, and to create a weight-reducing U-shaped groove.

[0022] Push block structure like Figure 2As shown, multiple push blocks 2 are arranged in an arc shape and are spaced apart along the outer ring surface of the boss 12. The outer ring surface of the push block 2 is provided with protrusions 21. A rubber sheet 3 is bonded to the inner ring surface (i.e., the pressing end) of the push block 2, and the thickness of the rubber sheet 3 is preferably 1 mm. When compressed, the rubber sheet 3 can increase the contact area with the insert 20, and at the same time, it can overcome the clamping problems caused by the size differences of different inserts due to tolerances and batches in powder metallurgy manufacturing.

[0023] There are gaps between the two ends of the push block 2 and its adjacent push blocks. These gaps can accommodate the processing of different types of inserts and can actively adapt to the deformation of the rubber sheet 3, leaving room for deformation and avoiding mutual interference, thereby tightly clamping the inserts.

[0024] Drive the structure of components like Figure 1 and Figure 3 As shown, multiple sets of pushing components are installed at intervals on the top edge of the base 1, which can drive the push block 2 to move radially along the base 1. Together with the boss 12, they can tightly clamp the insert 20, and the axial side (i.e. pressure surface) of the insert 20 can be machined by the cutting tool of the lathe.

[0025] The pushing assembly includes a guide plate 4 and a support plate 7 with lugs. The guide plate 4 is positioned by pins and fixed to the corresponding position on the base 1 by screws. The bottom surface of the guide plate 4 has a through groove 41 along the width direction. The through groove 41 is clearance-fitted with the protrusion 21, allowing the protrusion 21 of the push block 2 to slide linearly within the through groove 41.

[0026] Support plate 7 is arranged radially along base 1 and spaced apart from guide plate 4. Support plate 7 is fixed to corresponding positions on base 1 by screws. A clamping screw 8 is threaded onto the lug of support plate 7. One end (outer end) of clamping screw 8 is for external rotation (e.g., by tightening with a wrench), and the other end (inner end) is rotatably mounted on the side of protrusion 21 away from mounting hole 11. Specifically... The protrusion 21 has a mating groove (e.g., a T-slot) on its side away from the mounting hole 11. A limiting block (e.g., a T-shaped end) is provided at the inner end of the clamping screw 8. The limiting block can engage with the mating groove to allow free rotation. The groove opening is larger than the limiting block to prevent the limiting block from disengaging from the groove. In use, rotating the clamping screw 8 converts its rotation into linear motion along the radial direction of the base, due to the threaded engagement between the clamping screw 8 and the lug of the support plate 7. This pushes the push block 2 to move radially to clamp or hold the insert 20.

[0027] How to use tooling The following section, in conjunction with the above-described tooling structure, explains how to use this tooling.

[0028] Step 1: Measure the insert dimensions, calculate the fit clearance with the inner ring groove of the casing, and determine the machining dimensions and tolerances of the single-sided pressure surface.

[0029] Step 2: Loosen each clamping screw 8 with a wrench to remove the push block 2 so that the insert can be installed.

[0030] Step 3: Install the set of 80 inserts 20 in the annular groove of the base 1 with the bottom and side (pressure surface) positioned. At this time, the other side to be processed is located on top.

[0031] Step 4: Tighten each clamping screw 8 with a wrench so that the clamping surface (i.e., rubber sheet) of the push block 2 presses against the top surface of the insert 20.

[0032] Step 5: Hoist the tooling onto the lathe chuck using eye bolts, and adjust and fix it by aligning the reference circle on base 1 with a dial indicator.

[0033] Step 6: Adjust the lathe tool post angle to the insert pressure surface angle (e.g., 50°).

[0034] Step 7: Set the machining parameters for the machine tool or grinding machine, such as a rotation speed of 50 r / min, a feed rate of 0.08 mm / min, and no cutting fluid.

[0035] Step 8: Adjust the blade by adding a feeler gauge and making trial cuts.

[0036] Step 9: Perform machining according to the machining dimensions and tolerances calculated in Step 1.

[0037] Step 10: Loosen each clamping screw 8 with a wrench to remove the push block 2 and remove the insert 20.

[0038] Step 11: Measure the insert dimensions, calculate the fit clearance with the inner ring groove of the casing, and correct the machining dimensions and tolerances of the pressure surface on the other side.

[0039] Step 12: Position and install the set of more than 80 inserts 20 in the annular groove of the base 1 with the bottom surface and the processed side surface (pressure surface) in the position. At this time, the other side to be processed is located on the top.

[0040] Step 13: Tighten each clamping screw 8 with a wrench so that the clamping surface of the push block 2 presses against the top surface of the insert 20.

[0041] Step 14: Process according to the dimensions and tolerances corrected in Step 11. During processing, loosen one clamping screw 8 at an appropriate time to release the corresponding push block 2, remove one insert for dimensional measurement and trial assembly, correct the processing dimensions, reinstall the insert and process to the final dimensions, and then remove all inserts.

[0042] Secondly, an insert repair method is provided, employing some or all of the tooling described above. Since the top surface of the insert needs to be tightly fitted with the rotor's teeth after being clamped by the tooling, compensation is required for the worn portion of the insert's top surface. This method provides a rapid repair approach, improving repair efficiency, reducing repair time, and increasing repair accuracy. One trapezoidal surface of the insert (axial side, pressure surface, and trapezoidal surface all refer to the same surface) is used as the machined surface, and the other trapezoidal surface is used as the non-machined surface. The method includes the following steps: S1: Determine the amount of material removed during processing as ΔT, where, The thickness of the steel strip with pads and the machining dimensions of the top surface of the inserts are selected based on the wear measured by the inserts and the fit requirements between the inserts and the teeth, so as to determine the compensation dimension ΔR. The machining removal amount of the single-side pressure surface of the insert is determined by the pressure surface angle θ and the compensation size ΔR. The purpose is to add padding to the bottom surface and remove part of the side surface to ensure that there is enough margin after the top surface is lifted to restore the gap with the teeth on the casing. The distance ΔX is the distance the insert slides along the pressure surface of the non-machined surface until the pressure surface of the machined surface is in contact with the inner annular groove of the casing. According to geometric relationships, we have: (1) (2) Combining equations (1) and (2), we can obtain: (3); As can be seen from formula (3), the amount of material removed from the pressure surface of the insert machining surface can be determined as ΔT based on the compensation dimensions of the steel strip with padding.

[0043] S2: To ensure the symmetry of the dovetail shape of the insert, two machining operations are performed. First, the pressure surface of the machined surface is turned, and then the pressure surface of the non-machined surface is turned. That is, the machining allowance is evenly distributed to each side of the pressure surface. One side is machined first, and then the other side is flipped and clamped for machining. In addition, in actual machining, to ensure the fit clearance between the insert and the inner ring groove of the housing, a small allowance (0.05-0.1) can be appropriately left for the fitter's final repair. For example, θ=80°, and the shim compensation dimension can generally be selected as 0.3. Then, the machining removal amount of the single-sided pressure surface is 0.386, the machining amount evenly distributed to each side of the pressure surface is 0.193, and the removal amount of each side after leaving the fitter's repair allowance is 0.193 (-0.05--0.10). S3: After the insert is clamped by the tooling, it is turned according to the machining removal amount ΔT; for example, a dovetail-shaped sealing insert pressure surface combination machining tooling is used to perform group machining on the insert pressure surface.

[0044] S4: Steel strip with padding assembly and processing, in which... First, the shaped steel strip is padded and inserted into the inner ring groove of the housing. Then, the insert after removing the amount removed by ΔT is inserted to ensure that the two pressure surfaces of the insert are tightly fitted with the side of the inner ring groove, allowing a small amount of allowance for fitter repair. The entire assembly is mounted on a lathe, and the top surface of the insert is repaired to meet the clearance requirements for mating with the sealing teeth.

[0045] Furthermore, the selection of materials for steel strip with padding includes, Based on the materials of the insert and the inner ring parts on the casing, the fit clearance between the insert and the inner ring parts, the compensation dimension ΔR, and the raw material specifications of the steel strip with pads, the steel strip material and thickness group are determined. In this example, the steel strip material is 1Cr18Ni9Ti, and the thickness groups are 0.1, 0.2, 0.3, and 0.4, a total of 4 groups. The dimensions are designed according to the fit dimensions with the bottom surface of the insert and the inner ring, ensuring the largest possible contact area under the premise of no assembly interference, so as to make the fit more reliable.

[0046] The general approach is to first process the pressure surface to reduce the overall size of the insert, then add a steel strip of a certain thickness to the bottom surface of the insert to meet the fit with the inner ring groove of the casing. At the same time, a portion of the top surface of the insert is pushed out to compensate for the original worn part, and a small amount of allowance is left for the final surface dimension assembly processing to ensure the fit requirements with the sealing grates.

[0047] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A machining fixture for the pressure surface assembly of a dovetail-shaped sealing insert, applicable to the machining of multiple aerospace inserts, wherein the inserts are used for sealing the teeth of a sealing disc, characterized in that, include, The base (1) is mounted on the lathe chuck. A mounting hole (11) is opened in the middle area. A boss (12) is provided on the top surface of the mounting hole. An annular groove is provided in the radial direction of the base (1) and adjacent to the boss (12). The annular groove is used for the placement of multiple inserts (20). Multiple push blocks (2) with arc-shaped structures are distributed at intervals along the outer ring surface of the boss (12), and the outer ring surface is provided with protrusions (21). Multiple sets of pushing components are installed at intervals on the top edge of the base (1), which can drive the push block (2) to move radially along the base (1). In conjunction with the boss (12), the insert can be tightly clamped and the axial side of the insert can be machined by a cutting tool.

2. The tooling according to claim 1, characterized in that, The inner ring surface of the pusher (2) is bonded with a rubber sheet, which can increase the contact area with the insert after being squeezed.

3. The tooling according to claim 2, characterized in that, There are gaps between the two ends of the push block (2) and the adjacent push blocks. The gaps can be processed with different types of inserts and can actively adapt to the deformation of the rubber sheet, leaving deformation space and avoiding mutual interference.

4. The tooling according to claim 1, characterized in that, The propulsion component includes, The guide plate (4) has a through groove (41) on its bottom surface along the width direction, and the through groove (41) is in clearance fit with the protrusion (21); A support plate (7) with lugs is arranged radially along the base (1) and spaced apart from the guide plate (4). The lugs of the support plate (7) are threaded with a clamping screw (8). One end of the clamping screw (8) is used for external force rotation, and the other end is mounted on the side of the protrusion (21) away from the mounting hole (11) in a free-rotating manner.

5. The tooling according to claim 4, characterized in that, The protrusion (21) has a mating groove on the side away from the mounting hole (11). A limiting block is provided at one end of the clamping screw (8). The limiting block can be used for the free rotation of the mating groove, and the groove size of the mating groove is larger than the size of the limiting block to prevent the limiting block from coming off the mating groove. When in use, rotating the clamping screw (8) can push the push block (2) radially along the base to clamp or hold the insert.

6. An insert repair method, employing the tooling described in any one of claims 1 to 5, characterized in that, The method involves using one trapezoidal surface of the insert as a machined surface and the other trapezoidal surface as a non-machined surface, and includes the following steps. S1: Determine the amount of material removed during processing as ΔT, where, The thickness of the steel strip with pads and the machining dimensions of the top surface of the inserts are selected based on the wear measured by the inserts and the fit requirements between the inserts and the teeth, so as to determine the compensation dimension ΔR. The machining removal amount of the single-sided pressure surface of the insert is determined as ΔT based on the pressure surface angle of the insert and the compensation dimension ΔR. The distance ΔX is the distance the insert slides from its non-machined surface to its machined surface, where it contacts the inner annular groove of the housing. Based on geometric relationships, we have: （1） （2） Combining equations (1) and (2), we can obtain: （3）； As can be seen from formula (3), the amount of material removed from the pressure surface of the insert machining surface can be determined as ΔT based on the compensation dimensions of the steel strip with padding. S2: To ensure the symmetry of the insert dovetail shape, two machining processes are performed. First, the pressure surface of the machined surface is turned, and then the pressure surface of the non-machined surface is turned. S3: After the insert is clamped by the tooling, it is turned according to the machining removal amount ΔT; S4: Steel strip with padding assembly and processing, in which... First, the shaped steel strip is padded and inserted into the inner annular groove of the casing. Then, the insert after removing the amount of material removed by ΔT is inserted to ensure that the two pressure surfaces of the insert are in close contact with the side of the inner annular groove of the casing. The entire assembly is mounted on a lathe, and the top surface of the insert is repaired to meet the clearance requirements for mating with the sealing teeth.

7. The method according to claim 6, characterized in that, The materials selected for steel strip with padding include: The steel strip material and thickness group are determined based on the materials of the inserts and inner ring parts on the casing, the fit clearance between the inserts and the inner ring parts, the compensation dimension ΔR, and the raw material specifications of the steel strip with pads.

Images