A method for processing a seal ring assembly for an aeroengine

Abstract

The present application belongs to the technical field of precision machining of sealing parts of aero-engine, and particularly relates to a machining method of a sealing ring assembly for aero-engine. The present application adopts a process route of coupling of staged stamping and gradual circumferential rolling: firstly, 45° pre-bending and final flattening of the edge covering are sequentially completed through twice staged cold stamping, and the stamping peak stress is stepwise reduced and the internal residual stress distribution state of the edge covering is actively controlled; then the workpiece is coaxially clamped in a roller shape correcting clamp, and the upper and lower sides of the edge covering are continuously rolled and pressed by the double rollers in axial side-by-side manner along the whole circumference, so as to accumulate and correct the geometric deviation by multiple circles of slight plastic deformation, and the internal stress is released relying on the residual stress redistribution effect; the present application solves the technical problem that the single large plastic deformation of the existing cold stamping edge covering process causes local stress to be too high and elastic rebound to be serious, and further causes the edge covering to be loose, the butt joint gap and the parallelism of the assembly to be unable to stably meet the precision requirement of 0.02 mm.

Description

Technical Field

[0001] This invention relates to the field of precision machining technology for sealing components of aero engines, and in particular to a machining method for a sealing ring assembly for aero engines. Background Technology

[0002] The sealing ring assembly of an aero-engine is a core component of the gas passage sealing system. The quality of its edge-wrapping assembly directly determines the sealing interface's fit performance, thus affecting the overall operating efficiency and service reliability of the engine. Currently, the edge-wrapping process for sealing ring assemblies is generally carried out using cold stamping. This process has the characteristics of high forming efficiency, good batch consistency, and suitability for mass production, making it the mainstream processing method in the field of edge-wrapping forming of thin-walled annular metal parts.

[0003] In actual production, conventional cold stamping edge banding processes use a single stamping to complete the edge bending and flattening. The material undergoes large plastic deformation in a short period of time, resulting in excessively high local stress peaks at the edge banding area. After stamping unloading, the elastic rebound phenomenon is significant, ultimately leading to loose fit of the edge banding components. The parallelism between the edge banding gap and the overall end face of the component exceeds the tolerance, making it impossible to consistently meet the high-precision design requirement of 0.02mm. At the same time, affected by factors such as material performance fluctuations and mold wear, the springback amount has large dispersion, resulting in a low finished product qualification rate and numerous subsequent rework processes. This not only increases manufacturing costs but also makes it difficult to guarantee the high reliability delivery requirements of aero-engine components.

[0004] To address the issue of insufficient forming accuracy caused by stamping springback, the industry has proposed several improvement solutions. For example, the invention patent application with publication number CN116460227A, entitled "A Method for Forming C-Shaped Metal Sealing Rings Using Die Stamping," employs a process route of semi-circular ring pre-forming, overall die-pressing final forming, and roller-driven opening spinning shaping. By reducing the amount of deformation per stamping through step-by-step stamping and using rollers to correct the dimensions of the opening, it alleviates the dimensional deviation problem caused by local springback to a certain extent. However, this solution is designed for the cross-sectional contour forming of a single C-shaped sealing ring. The rollers only shape the opening of the ring body and cannot control the shape and position accuracy of the sealing ring assembly's entire circumference edge. It also does not address the root cause of springback from the perspective of residual stress release, making it difficult to simultaneously solve the technical challenges of edge loosening, achieving simultaneous compliance of the entire circumference butt joint gap and end face parallelism. Other existing improvement solutions mostly rely on CNC spinning equipment or stress-relief heat treatment processes, which have limitations such as large equipment investment, long process flow, and high processing costs, making them difficult to adapt to the needs of on-site, low-cost small-batch production. Therefore, it is necessary to develop a sealing ring assembly processing method with strong process adaptability and stable precision control, so as to achieve high-precision edge forming based on the existing cold stamping process. Summary of the Invention

[0005] This invention provides a processing method for sealing ring assemblies for aero engines, solving the technical problem that when existing aero engine sealing ring assemblies use cold stamping edge-wrapping processes, the large plastic deformation in a single process leads to excessive local stress and severe elastic rebound, resulting in loose edge wrapping and the inability to consistently meet the 0.02mm accuracy requirement for the mating gap and component parallelism.

[0006] To solve the above problems, the technical solution adopted by the invention is as follows: A method for manufacturing a sealing ring assembly for an aero-engine includes the following steps: (1) First edge preforming: The first forming punch is used to cold stamp the circumferential edge of the sealing ring blank, and the edge is bent to a 45° inclined state to complete the edge preforming. The stamping peak stress is reduced by step deformation. (2) Second pressing and flattening: The second forming punch is used to perform a second cold stamping on the pre-formed sealing ring blank, pressing the 45° inclined edge part to a state of flat contact with the surface of the component body, thus obtaining the initial forming sealing ring component, while controlling the residual stress distribution state inside the edge; (3) Workpiece clamping and positioning: The initial forming sealing ring assembly is coaxially clamped on the support ring of the roller straightening fixture; two heavy-duty support roller bearings are arranged side by side along the workpiece axis, and the working surfaces of the two rollers correspond to the upper and lower sides of the edge-wrapping part respectively. Adjust the position of the rollers so that they are close to the edge-wrapping part of the workpiece to be straightened and apply radial preload. (4) Progressive circumferential rolling and shaping: The rotating bracket of the driving shaping fixture rotates around the central axis, driving two heavy-duty support roller bearings to continuously roll and roll along the circumferential direction of the workpiece edge; each rolling only causes a small amount of plastic deformation to the edge, and the deformation is gradually accumulated through multiple rollings. At the same time, combined with the redistribution effect of residual stress, the edge butt gap and the overall parallelism of the component are corrected to obtain the finished sealing ring component.

[0007] The principle and advantages of this scheme are as follows: The working principle of this scheme is to first complete the main forming of the edge banding through two stages of cold stamping: the first stage of edge preforming bends the edge banding to a 45° tilt, breaking down the large single deformation into step deformation, effectively dispersing the degree of plastic deformation, reducing the local stress peak during the stamping process, and avoiding excessive internal stress concentration caused by the instantaneous and violent bending of the material; the second stage of edge flattening completes the final bonding between the edge banding and the component body on the basis of the preforming, so that the residual stress inside the edge banding is redistributed during the secondary deformation process, forming a more uniform stress state, and avoiding the high stress gradient inside the edge banding after a single stamping from providing continuous internal stress for subsequent springback. In the subsequent progressive circumferential rolling and shaping process, the upper and lower sides of the edge are clamped by axially arranged double rollers, and the edge is continuously rolled and rolled along the entire circumference of the edge with the rotating support. Each rolling only causes a small amount of plastic deformation to the edge. Through multiple rolling, the deformation is gradually accumulated to correct the macroscopic geometric deviation. At the same time, the external force of cyclic rolling will cause the residual stress inside the edge to be continuously redistributed, gradually releasing the internal stress remaining in the stamping process, suppressing elastic rebound from the mechanical source, and finally achieving synchronous optimization of the edge geometric accuracy and internal stress state.

[0008] Compared with existing technologies, existing technologies can only perform local dimensional shaping of the ring opening using rollers, and cannot achieve full-range control of the shape and position accuracy of the entire circumference edge of the sealing ring assembly. Furthermore, they do not address the core issue of elastic rebound caused by residual stress release. Therefore, it has always been difficult to simultaneously solve the technical problems of edge loosening, achieving the required circumference gap and end face parallelism. In addition, conventional single-pass cold stamping edge sealing processes are affected by factors such as material properties and mold wear, resulting in large dispersion of springback and significant fluctuations in finished product accuracy, which cannot reliably meet the high-precision design requirements of 0.02mm. This solution reduces peak stress and optimizes stress distribution at the forming source through two stages of edge pressing. Then, through full-circumference progressive rolling, it achieves a synergistic effect of geometric dimension correction and internal stress release. This not only consistently achieves a precision index of no more than 0.02mm for both edge-fitting gaps and overall component parallelism, significantly improving the finished product qualification rate and batch dimensional consistency, but also significantly enhances the long-term dimensional stability of the finished product due to the full release of internal stress. In subsequent assembly and high-temperature service environments, the precision decay caused by stress relaxation is far lower than that of conventional stamping processes, effectively ensuring the long-term sealing reliability of the sealing ring assembly. Furthermore, the entire process can be directly adapted to existing stamping production scenarios without the need for large-scale CNC spinning or heat treatment equipment. It boasts low processing costs and strong process adaptability, demonstrating significant application advantages in small-batch, high-precision processing scenarios for aerospace components.

[0009] Furthermore, in step (1), the blank holder force of the first stamping is controlled to be 60% to 70% of the theoretical forming force required for complete flattening of the edge, so that a residual compressive stress layer with a gradient distribution along the thickness direction of the edge is formed during the bending process of the edge; in step (2), the blank holder force of the second stamping is 1.2 to 1.5 times that of the first stamping blank holder force, and while flattening, the gradient residual compressive stress layer is reconstructed into a symmetrical residual stress field along the thickness direction of the edge; in the two stampings, the stamping speed of the first blank holder preforming is 0.6 to 0.8 times that of the second blank holder flattening stamping speed; the first stamping speed causes the material to undergo sufficient strain rate sensitive plastic flow during bending, forming a uniform gradient residual compressive stress layer; the second stamping speed causes the plastic deformation of the material during the flattening process to concentrate on the surface layer, suppressing further distortion of the deep lattice, and making the residual stress distribution of the edge section symmetrically converge; the setting of the blank holder force ratio and the stamping speed matching parameters can be achieved by different forming loads. The deformation rate allows for precise, layered control of residual stress within the edge banding: The first stamping uses a low load of 60%–70% of the theoretical forming force and a lower stamping speed, which prolongs the material's plastic flow time, allowing a uniformly gradient distribution of residual compressive stress layer in the thickness direction of the edge banding, thus avoiding excessively high local stress peaks caused by a single high-load stamping. The second stamping uses 1.2–1.5 times the blank holder force and a higher stamping speed than the first, concentrating plastic deformation only on the edge banding surface, limiting deep lattice distortion of the material, and reconstructing the unidirectional gradient stress formed in the first step into a symmetrically convergent residual stress field in the thickness direction. This significantly weakens the springback driving force caused by unidirectional stress, reducing the deformation correction amount in subsequent straightening processes from the stamping forming stage, reducing the risk of surface crushing and dimensional deviations caused by over-correction during rolling, and providing a more stable workpiece base with a stress state for subsequent progressive circumferential rolling straightening, ensuring that the final edge banding butt gap and component parallelism are stably controlled within 0.02mm.

[0010] Furthermore, the progressive rolling in step (4) adopts a graded radial feed method: after completing 1 to 2 rounds of circumferential rolling, the radial feed amount of the heavy-duty support roller bearing is adjusted by the rocker arm shaft; the feed amount is controlled according to the following strategy: in the first 1 / 3 of the total rolling rounds, the single radial feed amount is controlled at 0.010mm to 0.015mm to quickly eliminate the macroscopic geometric deviation of the edge; in the middle 1 / 3 of the total rolling rounds, the single radial feed amount is reduced to 0.005mm to 0.010mm for progressive finishing; in the last 1 / 3 of the total rolling rounds, the single radial feed amount is controlled below 0.005mm for finishing rolling; the three-stage feed strategy allows the workpiece edge to gradually transition from coarse correction to finishing, avoiding excessive local correction and surface crushing caused by a constant large feed amount; the three-stage decreasing radial feed strategy is based on the coarse correction The finishing and smoothing processes are matched with differentiated feed rates in stages. In the early stage, a larger single feed rate of 0.010mm to 0.015mm is used to quickly eliminate macroscopic geometric deviations such as warping and misalignment of the edge after stamping, shortening the overall straightening processing time. In the middle stage, the feed rate is reduced to 0.005mm to 0.010mm to achieve gradual micro-adjustment, gradually converging the gap and parallelism deviation of the edge butt joint, and preventing excessive local straightening caused by a large feed extrusion at one time. In the later stage, an extremely small feed rate of less than 0.005mm is used for smoothing and rolling, further homogenizing the surface stress of the edge and optimizing the surface forming quality. The entire feed scheme completes the entire accuracy correction process step by step, avoiding defects such as local overpressure of materials, surface crushing, and secondary stress concentration caused by constant large feed throughout the process, while taking into account the straightening processing efficiency and the dimensional accuracy and surface quality of the finished product.

[0011] Furthermore, the progressive circumferential rolling and shaping in step (4) adopts a staged variable pressure rolling strategy: the rolling process is divided into three stages: the rough rolling stage, i.e., the first to the third round, the radial rolling pressure of the heavy-duty support roller bearing is set to the first pressure level, the first pressure level corresponds to the contact stress of 30% to 40% of the yield strength of the workpiece edge material, so that the edge produces preliminary plastic deformation to eliminate macroscopic warping; the fine rolling stage, i.e., the fourth to the eighth round, the radial rolling pressure is reduced to the second pressure level, the second pressure level is 50% to 65% of the first pressure level, so that the edge undergoes slight creep deformation under a small contact stress, gradually correcting the parallelism deviation; the finishing stage, i.e. after the ninth round, the radial rolling pressure is reduced to the third pressure level, the third pressure level is 20% to 35% of the first pressure level, and the edge surface is rolled and finished to reduce surface roughness and stabilize the final dimensional accuracy; the staged variable pressure rolling strategy matches the gradient decreasing contact stress according to the deformation requirements of different stages of edge correction, the rough rolling stage adopts material The high contact stress of 30%–40% of the material's yield strength can quickly overcome residual internal stress from stamping, allowing the edge to undergo sufficient initial plastic deformation and efficiently eliminating overall macroscopic warping deformation. In the finishing stage, the pressure is reduced to 50%–65% of the roughing pressure, relying on slight creep deformation under low stress to slowly correct end-face parallelism deviations, avoiding localized over-deformation and secondary stress concentration caused by high-pressure extrusion. In the finishing stage, the pressure is further reduced to 20%–35% of the roughing pressure, relying solely on gentle rolling to evenly smooth the microscopic unevenness of the edge surface and release residual micro-stress. While reducing the surface roughness of the parts, it also locks in the corrected dimensional accuracy. The entire variable pressure scheme achieves multiple objectives in stages: macroscopic defect elimination, fine correction of form and position accuracy, surface quality optimization, and dimensional stability. While ensuring shaping efficiency, it completely avoids problems such as uncontrolled edge deformation, surface damage, and springback recurrence caused by high-pressure rolling throughout the process, stably guaranteeing the 0.02mm level form and position accuracy requirements of the finished product.

[0012] Furthermore, in step (4), the total number of rolling cycles in the rolling process is set to 8 to 15. During the rolling process, the workpiece remains fixed and does not rotate, and only the heavy-duty support roller bearings perform planetary circumferential rolling around the workpiece. The two heavy-duty support roller bearings revolve around the central axis of the workpiece at the same angular velocity under the drive of the rotating bracket, while each roller rotates on its own under the drive of the contact friction force on the edge surface of the workpiece. After rolling, the edge butt gap of the sealing ring assembly is ≤0.02mm, and the overall parallelism of the assembly is ≤0.02mm. Limiting the total number of rolling cycles to 8 to 15 can balance the efficiency of the shaping process and the degree of stress release. If the number of cycles is too small, the residual stress will not be released completely and the accuracy will be difficult to meet the standard. If the number of cycles is too large, it will prolong the processing cycle and cause Excessive rolling damage to the material surface; In the motion mode of fixing the workpiece and the two rollers performing planetary revolution and rotation, the two sets of rollers rotate around the workpiece synchronously at a constant angular velocity. The rotation of the rollers is driven by the friction of the contact surface, which can ensure that the entire circumference of the edge is continuously, uniformly and without interruption, without local missed rolling or uneven force. It can synchronously and uniformly correct the butt joint gap and end face height difference within the entire circumference. Relying on the combination constraint of this motion and the quantitative rolling circle, the butt joint gap of the finished edge and the overall parallelism of the component can be stably controlled within 0.02mm, ensuring the consistency of the shape and position accuracy of the entire edge and avoiding the defects of slippage, insufficient local rolling amount and large circumferential accuracy dispersion caused by the synchronous rotation of the workpiece with the rollers.

[0013] Furthermore, in step (3), the pressing end face of the pressure plate is provided with a wedge-shaped bevel surface. In the clamping state, the wedge-shaped bevel surface of the pressure plate cooperates with the corresponding bevel surface of the support ring to form a wedge-shaped self-locking structure; the wedge angle of the wedge-shaped bevel surface satisfy The conditions, among which The wedge-shaped friction angle is used to describe the axial reaction force generated by the rolling pressure on the workpiece during the rolling process. This force is decomposed into a radial clamping force and an axial self-locking force through the wedge-shaped angle. When the rolling vibration causes a slight axial loosening tendency in the workpiece, the wedge-shaped angle automatically converts the axial loosening force into a radial amplifying force, causing the radial clamping force to adaptively increase with the increase of the axial loosening tendency. This creates a negative feedback self-reinforcing clamping effect where the larger the vibration amplitude, the stronger the radial clamping force. The wedge-shaped self-locking structure formed by the cooperation of the pressure plate and the support ring can achieve adaptive anti-loosening clamping based on the mechanical decomposition of the wedge surface. During the rolling operation, the rolling pressure applied by the roller to the workpiece will generate an axial reaction force, which is decomposed through the wedge... The wedge-shaped inclined plane separates the radial clamping force and the axial self-locking force. Once the workpiece tends to loosen axially due to processing vibration, the resulting axial loosening force will be automatically converted into additional radial force through the wedge-shaped inclined plane. This creates a negative feedback self-reinforcing effect where the larger the vibration amplitude, the stronger the radial clamping force. It can compensate for the clamping gap caused by vibration in real time, maintain the coaxial positioning accuracy of the workpiece and the support ring throughout the process, and prevent the workpiece from axially shifting or radially swaying during the straightening process. It also prevents problems such as uneven local compaction, edge parallelism, and excessive butt joint gap caused by clamping looseness. There is no need for manual re-tightening of the tooling midway. While simplifying the operation, it continuously ensures the accuracy and stability of the full-circumference compaction correction.

[0014] Furthermore, after step (2) is completed and before step (3) begins, a room temperature natural aging process is set: the initially formed sealing ring assembly is left to stand at room temperature for 2-4 hours; the aging time t satisfies: ,in The aging coefficient is related to the material. This represents the maximum residual stress value in the thickness direction of the edge banding after step (2) is completed. The elastic modulus of the material. The thickness of the edge is determined by the following: The residual stress peak at the edge is reduced by 15%–25% through natural aging, while retaining the basic distribution of the symmetrical residual stress field formed in step (2). This ensures that the residual stress state of the workpiece is in a pre-adjusted state with low amplitude but favorable distribution when entering the rolling and shaping process. After the second stamping is completed, a 2–4 ​​hour room temperature natural aging process is added, and the static time is controlled by a quantitative aging formula matching the material properties. This can reduce the residual stress peak in the edge thickness direction by 15%–25%, which can weaken the excessively high stress amplitude inside the workpiece in advance and reduce the subsequent rolling and shaping. It eliminates the risks of stress rebound and uncontrolled deformation, without disrupting the symmetrical residual stress field distribution established by the stamping process. This allows the workpiece to form a low-amplitude, regularly distributed pre-stress state before entering the rolling process, significantly reducing the total amount of internal stress that needs to be offset during the shaping stage, reducing the deformation load required for roller rolling, reducing surface damage and dimensional over-correction caused by excessive rolling, improving the correction effect of graded feed and variable pressure rolling strategies, shortening the number of rolling cycles required to achieve the 0.02mm accuracy standard, and eliminating the need for heating and aging equipment, thus simplifying the process and reducing processing energy consumption and production costs.

[0015] Furthermore, in the rolling and shaping process of step (4), a vibration acceleration sensor is installed on the bearing seat of the heavy-duty support roller bearing to collect the vibration signal of the roller in real time during the rolling process; the rolling and shaping process is judged by the trend of the root mean square value (RMS) of the vibration signal: when the relative decrease rate of the RMS value in two consecutive rolling cycles is lower than the preset threshold ε, it is determined that the plastic deformation of the workpiece edge has tended to stabilize, and the current number of cycles is the optimal number of rolling cycles to terminate; when the optimal number of rolling cycles to terminate is reached, the rolling is automatically stopped; the preset threshold ε is the threshold of the relative decrease rate of the root mean square value between cycles, and the value is 5% / cycle to 10% / cycle; by arranging a vibration acceleration sensor on the roller bearing seat to collect the rolling vibration signal in real time, and using the relative decrease rate of the root mean square value (RMS) of the vibration for two consecutive cycles of 5% / cycle to 10% / cycle as the judgment threshold, the rolling and shaping process can be objectively quantified. The system achieves a stable state of edge plastic deformation, replacing the traditional one-size-fits-all control method with a fixed number of rolls. In the early stages of the forming process, when the geometric deviation of the edge is large and continuous plastic deformation occurs, the rolling vibration amplitude decreases significantly and the RMS drop rate is higher than the threshold. The equipment continues to perform rolling operations. As the edge dimensions are gradually corrected and the plastic deformation tends to saturate, the vibration fluctuations are significantly reduced. When the RMS drop rate is lower than the threshold, the correction is considered complete and the machine automatically stops. This avoids insufficient stress release and substandard form and position accuracy caused by premature termination of rolling, as well as unnecessary extension of the rolling number, which can lead to excessive rolling damage to the workpiece surface and reduced processing efficiency. The system can adaptively match the optimal rolling time according to the individual differences in the springback of each workpiece, uniformly ensuring the forming accuracy and surface quality of batch products. At the same time, it realizes automated judgment and shutdown of the forming process, reduces manual inspection intervention, and improves processing consistency and production efficiency.

[0016] Furthermore, after step (4) is completed, a precision closed-loop control step is set: a dial indicator is used to detect the overall parallelism of the sealing ring assembly and the gap between the edges; if the detected value exceeds the preset precision threshold, a supplementary compaction strategy is determined based on the deviation Δ: when At that time, control the heavy-duty support roller bearing to add one round of rolling to the workpiece, and the rolling pressure is 80% to 100% of the rolling pressure in the finishing stage of step (4); when At that time, add 2 more passes of rolling, with the rolling pressure being 60% to 80% of the rolling pressure in the finishing stage of step (4); when At that time, add 3 rounds of rolling, with the rolling pressure being 70% to 90% of the rolling pressure in the fine rolling stage of step (4); until the test value meets the design requirements; this precision closed-loop control step accurately quantifies the deviation Δ of the edge-to-edge gap and component parallelism through a dial indicator, and matches the differentiated number of rolling rounds and rolling pressure according to the three deviation ranges. When the deviation Δ≤0.01mm is a slight deviation, only 1 round of rolling is added with pressure close to the finishing stage, and the size is finely adjusted by a small amount of gentle rolling, which will not damage the surface quality and internal stable stress field of the edge that has been formed; when there is a medium deviation of 0.01mm<Δ≤0.02mm, the number of rolling rounds is increased while the pressure is appropriately reduced. The rolling pressure slowly and evenly converges the shape and position deviations, avoiding local over-deformation caused by high-pressure concentrated extrusion. When Δ>0.02mm is a significant deviation, the pressure is switched to the fine rolling zone and three additional rolling cycles are performed to efficiently eliminate the remaining macroscopic warping and gap deviations. The entire graded rolling scheme can accurately match the correction strength according to the actual defects of each workpiece, avoiding problems such as edge crushing, dimensional deviations, and secondary concentration of surface stress caused by repeated high-pressure rework. It forms a closed-loop processing logic of detection, graded compensation, and re-inspection, stably controlling the shape and position accuracy of the finished product within the design standard of 0.02mm, significantly reducing the scrap rate of parts and improving the dimensional consistency and processing yield of batch products.

[0017] Furthermore, the roller straightening fixture is fixed in place by clamping it to a vise via a bottom fixing block; a deep groove ball bearing is installed between the rotating support and the central shaft as a rotary support pair; a galvanized steel pipe is used as the power input rocker arm, and the manual torque is transmitted to the rotating support through a bearing linkage mechanism, driving the heavy-duty support roller bearing to synchronously achieve the rotary motion around the central shaft and the radial feed adjustment; the support ring is fixedly connected to the central shaft, and the outer diameter of the support ring and the inner diameter of the sealing ring assembly are in clearance fit, with the clearance controlled between 0.02mm and 0.05mm. The clearance fit between the inner hole of the workpiece and the outer wall of the support ring is used to achieve the workpiece straightening... Radial coaxial positioning; the rolling working surface of the heavy-duty support roller bearing is an arc-shaped surface, the radius of curvature of the arc-shaped surface matches the radius of curvature of the outer contour of the sealing ring edge, and the radius of curvature deviation is ≤0.01mm; the hardness of the working surface of the heavy-duty support roller bearing is ≥HRC50, and the rotation axis of the roller under rolling condition is perpendicular to the radial direction of the workpiece center axis; the roller straightening fixture adopts a modular, low-cost, universal assembly structure and high-precision fit design, and can complete the overall clamping and fixing by means of the bottom fixed clamping block and vise, without the need for a special large tooling base, and is suitable for conventional processing stations in the workshop; the rotating bracket and the middle A deep groove ball bearing is used between the spindles to form a rotary support pair, ensuring smooth rotation and small backlash, guaranteeing a stable and uninterrupted revolution of the rollers around the workpiece. A galvanized steel pipe is used as the manual power rocker arm, which, in conjunction with a bearing linkage mechanism, synchronously transmits torque to adjust the rotation of the support and the radial feed of the rollers. This design is simple, easy to operate, and inexpensive to manufacture. The support ring is rigidly fixed to the central shaft, with a reasonable clearance of 0.02mm to 0.05mm between the outer diameter of the support ring and the inner diameter of the workpiece. This facilitates quick assembly and disassembly of the workpiece while limiting radial offset, ensuring coaxial positioning accuracy throughout the entire rolling process. The roller rolling surface uses a combination of [missing information - likely a specific material or design element]. The outer contour is matched with an arc-shaped surface, and the radius of curvature deviation is controlled within 0.01mm. The hardness of the working surface is not lower than HRC50. During rolling, the roller axis is radially perpendicular to the center of the workpiece, which allows the roller and the edge surface to fit completely and make uniform contact. This avoids edge depressions, stress concentration and uneven force caused by local point pressure. At the same time, the high-hardness roller has low wear resistance and can maintain the rolling contact surface shape accuracy even under long-term batch processing. The whole tooling takes into account the convenience of processing, low cost, rotational stability, coaxial positioning accuracy and rolling fit uniformity, and stably ensures that the edge butt gap and parallelism are controlled within the accuracy requirement of 0.02mm. Attached Figure Description

[0018] Figure 1 This is a flowchart of the method of the present invention; Figure 2 This is a cross-sectional view of the component processing, installation, and fixing of the present invention; Figure 3 This is a schematic diagram of the fabrication and fixing of the sealing ring assembly of the present invention.

[0019] The reference numerals in the accompanying drawings include: 1. Base; 2. Socket head cap screw; 3. Fixed shaft; 4. Socket head cap screw; 5. Fixed clamping block; 6. Central shaft; 7. Rotating bracket; 8. Support ring; 9. Pressure plate; 10. Socket head cap screw; 11. Anti-slip sleeve; 12. Galvanized steel pipe; 13. Wing welded bolt; 14. Deep groove ball bearing; 15. Socket head countersunk screw; 16. Countersunk shaft end retaining ring; 17. Cylindrical pin; 18. Rocker arm shaft; 19. Heavy-duty support roller bearing; 20. Countersunk washer; 21. Socket head countersunk screw; 22. Workpiece; 23. Detailed Implementation Example 1 like Figure 1-3 As shown, the processing method for the sealing ring assembly for aero-engines in this embodiment involves primary forming of the edge by staged cold stamping, followed by progressive circumferential rolling and shaping using a dedicated roller shaping fixture, ultimately achieving high-precision forming. The specific structure of the roller shaping fixture and the processing steps are as follows: A base 1 is provided at the bottom of the fixture. The lower end face of the base 1 is fixedly connected to a fixing block 5 by a hexagon socket head cap screw 2. The fixing block 5 can be clamped onto a machine tool vise to achieve a fixed installation of the entire fixture. A fixing shaft 3 is coaxially fixed to the center of the base 1 by a hexagon socket head cap screw 4. The upper end of the fixing shaft 3 is coaxially fixedly connected to a central shaft 6, which serves as the rotation reference axis of the fixture.

[0020] A rotating bracket 7 is fitted around the outside of the central shaft 6. A deep groove ball bearing 15 is installed between the rotating bracket 7 and the central shaft 6 as a rotational support pair. The inner ring of the deep groove ball bearing 15 is fitted with the central shaft 6, and the outer ring is fitted with the inner hole of the rotating bracket 7. The upper end of the bearing is axially limited by a countersunk shaft end retaining ring 17 and an internal hexagon countersunk screw 16, so that the rotating bracket 7 can rotate smoothly and with low clearance around the axis of the central shaft 6.

[0021] The top end of the central shaft 6 is coaxially fixed to a support ring 8 via a thread. The support ring 8 is used to support the workpiece 23 (initial forming sealing ring assembly). The outer diameter of the support ring 8 and the inner diameter of the sealing ring assembly are fitted with a clearance, with the clearance controlled between 0.02mm and 0.05mm. The radial coaxial positioning of the workpiece is achieved through the fit between the inner hole of the workpiece and the outer wall of the support ring 8. An annular pressure plate 10 is provided above the support ring 8. The pressure plate 10 is connected to the support ring 8 by multiple hexagonal head screws 11, which are used to axially press and fix the workpiece 23 to the end face of the support ring 8. The pressing end face of the pressure plate 10 is machined with a wedge-shaped bevel. In the clamping state, the wedge-shaped bevel of the pressure plate 10 and the corresponding bevel on the upper end of the support ring 8 fit together to form a wedge-shaped self-locking structure. The wedge angle of the wedge-shaped bevel is... satisfy The conditions, among which The friction angle between the wedge surfaces. During the rolling process, the axial reaction force generated by the rolling pressure of the workpiece is decomposed into radial clamping force and axial self-locking force by the wedge-shaped oblique angle; when the rolling vibration causes the workpiece to have a slight tendency to loosen axially, the wedge-shaped oblique surface automatically converts the axial loosening force into radial amplification force, forming a negative feedback self-reinforcing clamping effect.

[0022] A rocker arm shaft 19 is mounted on the cantilever end of the rotating bracket 7. The rocker arm shaft 19 is circumferentially fixed to the rotating bracket 7 by a cylindrical pin 18, and its radial position can be adjusted by a threaded pair. Two heavy-duty support roller bearings 20 are mounted side by side on the rocker arm shaft 19. The two heavy-duty support roller bearings 20 are arranged vertically along the workpiece axis, and the working surfaces of the two rollers correspond to the upper and lower sides of the workpiece edging area, respectively. The rolling working surface of the heavy-duty support roller bearing 20 is an arc-shaped surface, and the radius of curvature of this arc-shaped surface matches the radius of curvature of the outer contour of the sealing ring edging, with a radius of curvature deviation ≤ 0.01 mm. The hardness of the working surface of the heavy-duty support roller bearing 20 is ≥ HRC50, and the rotation axis of the roller is perpendicular to the radial direction of the workpiece center axis under rolling conditions.

[0023] The side wall of the rotating bracket 7 is welded with a butterfly welded bolt 14. The galvanized steel pipe 13 is used as a power input rocker arm and is fixed on the butterfly welded bolt 14. The gripping end of the galvanized steel pipe 13 is fitted with an anti-slip sleeve 12. By manually rotating the galvanized steel pipe 13, the torque can be transmitted to the rotating bracket 7, which will drive the rotating bracket 7 to rotate around the central axis 6. At the same time, the radial feed of the heavy-duty support roller bearing 20 can be adjusted synchronously through the rocker arm shaft 19.

[0024] Processing method steps (1) The first pre-forming of the edge clamping uses a first forming punch that matches the edge contour of the blank to cold stamp the circumferential edge of the aero-engine sealing ring blank, bending the straight edge to a 45° inclined state to complete the edge clamping pre-forming. In this step, the edge clamping force of the first stamping is controlled to be 65% of the theoretical forming force required to completely flatten the edge, and the stamping speed is set to 0.7 times the second stamping speed. The lower stamping speed prolongs the plastic flow time of the material, so that a residual compressive stress layer with a gradient distribution along the thickness direction is formed in the edge clamping part during the bending process. The degree of plastic deformation is dispersed by step deformation, the peak stress of stamping is reduced, and the excessive local stress caused by a single large deformation is avoided.

[0025] (2) The second pressing and flattening process involves using a second forming punch to perform a second cold stamping on the pre-formed sealing ring blank, pressing the 45° inclined edge portion until it is completely flat against the surface of the component body, thus obtaining the initial formed sealing ring component. In this step, the pressing force of the second stamping is 1.3 times that of the first stamping, and the stamping speed is higher than that of the first stamping. The higher stamping speed causes the plastic deformation of the material during the flattening process to concentrate on the edge surface layer, suppressing further distortion of the deep lattice, reconstructing the gradient residual compressive stress layer formed in the first step into a symmetrical residual stress field along the edge thickness direction, weakening the springback driving force brought by unidirectional stress, and reducing the risk of subsequent springback from the forming stage.

[0026] (3) Natural aging at room temperature: The initial forming sealing ring assembly completed by the second stamping is placed in a clean environment at room temperature and left to stand for 3 hours. The aging time t satisfies the following quantitative formula: ,in, An aging coefficient related to the workpiece material. E represents the maximum residual stress value in the thickness direction of the edge banding after step (2), where E is the elastic modulus of the material and h is the edge banding wall thickness. Natural aging reduces the peak residual stress in the edge banding area by 15% to 25%, while retaining the basic distribution of the symmetrical residual stress field formed in step (2), so that when the workpiece enters the rolling and shaping process, the residual stress is in a pre-adjusted state with a low amplitude but favorable distribution.

[0027] (4) Workpiece clamping and positioning: The pre-formed sealing ring assembly after aging treatment is coaxially mounted on the support ring 8 of the roller straightening fixture. Radial coaxial positioning is achieved by the clearance fit between the inner hole of the workpiece and the outer wall of the support ring 8. Then, the pressure plate 10 is placed and each hexagonal head screw 11 is tightened evenly to axially press and fix the workpiece. The wedge-shaped inclined surface of the pressure plate and the support ring cooperate to form a self-locking clamp. Adjust the radial position of the rocker arm shaft 19 so that the working surfaces of the two heavy-duty support roller bearings 20 are respectively attached to the upper and lower surfaces of the workpiece edge, and apply the set radial preload to ensure that the roller working surface and the edge surface are completely and evenly attached.

[0028] (5) Progressive circumferential rolling and shaping: The galvanized steel pipe 13 drives the rotating support 7 to rotate uniformly around the central axis 6, driving the two heavy-duty support roller bearings 20 to continuously roll and roll along the circumferential direction of the workpiece edge. During the rolling process, the workpiece remains fixed and does not rotate, only the heavy-duty support roller bearings 20 make planetary circular motion around the workpiece; the two rollers revolve around the center of the workpiece at the same angular velocity under the drive of the rotating support, and at the same time, each roller rotates on its own under the drive of the contact friction force on the edge surface.

[0029] In this embodiment, the total number of compaction cycles is set to 12, and the compaction process adopts a control strategy that combines staged radial feed and phased pressure variation: Graded radial feed: After each circumferential compaction revolution, the radial feed amount of the heavy-duty support roller bearing 20 is adjusted once via the rocker arm shaft 19. For the first four revolutions (the first third of the total revolutions), the single radial feed amount is controlled at 0.012 mm to quickly eliminate macroscopic warping and geometric deviations in the edge. For the middle four revolutions (the middle third of the total revolutions), the single radial feed amount decreases to 0.008 mm for progressive finishing and gradually reducing dimensional deviations. For the last four revolutions (the last third of the total revolutions), the single radial feed amount is controlled at 0.003 mm for finishing compaction and optimizing surface quality.

[0030] Staged variable pressure rolling: Rounds 1 to 3 are the rough rolling stage, where the radial rolling pressure of the heavy-duty support roller bearing is set to the first pressure level, corresponding to a contact stress of 35% of the yield strength of the workpiece edge material, causing initial plastic deformation of the edge and quickly eliminating macroscopic warping; Rounds 4 to 8 are the fine rolling stage, where the radial rolling pressure is reduced to the second pressure level, which is 60% of the first pressure level, causing slight creep deformation of the edge under low contact stress, gradually correcting the deviation between the parallelism of the components and the gap between the edge and the joint; Rounds 9 to 12 are the finishing stage, where the radial rolling pressure is reduced to the third pressure level, which is 30% of the first pressure level, rolling and finishing the edge surface to reduce surface roughness and stabilize the final dimensional accuracy.

[0031] During the compaction process, a vibration acceleration sensor is installed on the bearing seat of the heavy-duty support roller bearing 20 to collect the vibration acceleration signal of the roller in real time. The root mean square (RMS) value of the vibration signal is calculated, and its changing trend is used to determine the compaction and shaping progress. The preset relative decrease rate threshold ε between compaction cycles is 8% / cycle. When the relative decrease rate of the RMS value in two consecutive compaction cycles is lower than this threshold, it is determined that the plastic deformation of the workpiece edge has stabilized, and the current number of cycles is the optimal number of compaction cycles to terminate, and compaction can be stopped in advance.

[0032] After compaction, the edge-sealing gap of the finished sealing ring assembly is ≤0.02mm, and the overall parallelism of the assembly is ≤0.02mm.

[0033] (6) After the precision closed-loop control compaction process is completed, a dial indicator is used to perform a full-circumference inspection on the overall parallelism of the sealing ring assembly and the gap between the edges; if the detected value exceeds the preset precision threshold, a supplementary compaction strategy is determined based on the deviation amount (Delta). when At that time, control the heavy-duty support roller bearing to add one round of rolling to the workpiece, with the rolling pressure being 90% of the rolling pressure in the finishing stage; when At that time, add 2 more passes of compaction, with a compaction pressure of 70% of the compaction pressure during the finishing stage; when Then, perform 3 additional compaction passes, with a compaction pressure of 80% of the compaction pressure during the finishing compaction stage. After the additional compaction is completed, perform another test, and repeat the above process until the test values ​​meet the design accuracy requirements.

Claims

1. A method for processing a sealing ring assembly for an aero-engine, characterized in that, Includes the following steps: (1) First edge preforming: The first forming punch is used to cold stamp the circumferential edge of the sealing ring blank, and the edge is bent to a 45° inclined state to complete the edge preforming. The stamping peak stress is reduced by step deformation. (2) Second pressing and flattening: The second forming punch is used to perform a second cold stamping on the pre-formed sealing ring blank, pressing the 45° inclined edge part to a state of flat contact with the surface of the component body, thus obtaining the initial forming sealing ring component, while controlling the residual stress distribution state inside the edge; (3) Workpiece clamping and positioning: The initial forming sealing ring assembly is coaxially clamped on the support ring of the roller straightening fixture; two heavy-duty support roller bearings are arranged side by side along the workpiece axis, and the working surfaces of the two rollers correspond to the upper and lower sides of the edge-wrapping part respectively. Adjust the position of the rollers so that they are close to the edge-wrapping part of the workpiece to be straightened and apply radial preload. (4) Progressive circumferential rolling and shaping: The rotating bracket of the driving shaping fixture rotates around the central axis, driving two heavy-duty support roller bearings to continuously roll and roll along the circumferential direction of the workpiece edge; each rolling only causes a small amount of plastic deformation to the edge, and the deformation is gradually accumulated through multiple rollings. At the same time, combined with the redistribution effect of residual stress, the edge butt gap and the overall parallelism of the component are corrected to obtain the finished sealing ring component.

2. The processing method of the aero-engine sealing ring assembly according to claim 1, characterized in that, In step (1), the blank holder force of the first stamping is controlled to be 60% to 70% of the theoretical forming force required for complete flattening of the edge, so that a residual compressive stress layer with a gradient distribution along the thickness direction of the edge is formed during the bending process of the edge. In step (2), the blank holder force of the second stamping is 1.2 to 1.5 times that of the first stamping. While flattening, the gradient residual compressive stress layer is reconstructed into a symmetrical residual stress field along the thickness direction of the edge. In the two stampings, the stamping speed of the first blank holder preforming is 0.6 to 0.8 times that of the second blank holder flattening stamping speed. The first stamping speed causes the material to undergo sufficient strain rate sensitive plastic flow during bending, forming a uniform gradient residual compressive stress layer. The second stamping speed causes the plastic deformation of the material during the flattening process to be concentrated on the surface layer, suppressing further distortion of the deep lattice, so that the residual stress distribution of the edge section is in a symmetrical convergent state.

3. The processing method of a sealing ring assembly for an aero-engine according to claim 1, characterized in that, The progressive rolling in step (4) adopts a graded radial feed method: after each 1-2 rounds of circumferential rolling, the radial feed of the heavy-duty support roller bearing is adjusted by the rocker arm shaft; the feed is controlled according to the following strategy: in the first 1 / 3 of the total rolling rounds, the single radial feed is controlled at 0.010mm to 0.015mm to quickly eliminate the macroscopic geometric deviation of the edge; in the middle 1 / 3 of the total rolling rounds, the single radial feed is reduced to 0.005mm to 0.010mm for progressive finishing; in the last 1 / 3 of the total rolling rounds, the single radial feed is controlled below 0.005mm for finishing rolling; the three-stage feed strategy allows the edge of the workpiece to gradually transition from coarse to fine finishing, avoiding excessive local shaping and surface crushing caused by a constant large feed.

4. The processing method of a sealing ring assembly for an aero-engine according to claim 1, characterized in that, The progressive circumferential rolling and shaping in step (4) adopts a phased variable pressure rolling strategy: the rolling process is divided into three stages: the rough rolling stage, i.e. the first to the third round, the radial rolling pressure of the heavy-duty support roller bearing is set to the first pressure level, the first pressure level corresponds to the contact stress of 30% to 40% of the yield strength of the workpiece edge material, so that the edge produces preliminary plastic deformation to eliminate macroscopic warping. In the finishing stage, from the 4th to the 8th round, the radial rolling pressure is reduced to the second pressure level, which is 50% to 65% of the first pressure level. This causes slight creep deformation of the edge under relatively small contact stress, gradually correcting the parallelism deviation. In the finishing stage, from the 9th round onwards, the radial rolling pressure is reduced to the third pressure level, which is 20% to 35% of the first pressure level. This rolling and finishing process smooths the edge surface, reducing surface roughness and stabilizing the final dimensional accuracy.

5. The method for processing a sealing ring assembly for an aero-engine according to claim 1, characterized in that, In step (4), the total number of rolling cycles in the rolling process is set to 8 to 15. During the rolling process, the workpiece remains fixed and does not rotate. Only the heavy-duty support roller bearings perform planetary circumferential rolling around the workpiece. The two heavy-duty support roller bearings revolve around the central axis of the workpiece at the same angular velocity under the drive of the rotating bracket. At the same time, each roller rotates on its own under the drive of the contact friction force on the edge of the workpiece. After rolling, the edge butt gap of the sealing ring assembly is ≤0.02mm, and the overall parallelism of the assembly is ≤0.02mm.

6. A method for processing a sealing ring assembly for an aero-engine according to claim 1, characterized in that, In step (3), the pressing end face of the pressure plate is provided with a wedge-shaped bevel. In the clamping state, the wedge-shaped bevel of the pressure plate cooperates with the corresponding bevel of the support ring to form a wedge-shaped self-locking structure; the wedge angle of the wedge-shaped bevel is... satisfy The conditions, among which The wedge friction angle is used to describe the axial reaction force generated by the rolling pressure on the workpiece during the rolling process. This force is decomposed into a radial clamping force and an axial self-locking force by the wedge-shaped angle. When the rolling vibration causes the workpiece to have a slight tendency to loosen axially, the wedge-shaped angle automatically converts the axial loosening force into a radial amplifying force. This causes the radial clamping force to increase adaptively with the increase of the axial loosening tendency, forming a negative feedback self-reinforcing clamping effect where the larger the vibration amplitude, the stronger the radial clamping force.

7. A method for processing a sealing ring assembly for an aero-engine according to claim 1, characterized in that, After step (2) is completed and before step (3) begins, set up a room temperature natural aging process: let the initially formed sealing ring assembly stand at room temperature for 2-4 hours; the aging time t satisfies: ,in The aging coefficient is related to the material. This represents the maximum residual stress value in the thickness direction of the edge banding after step (2) is completed. The elastic modulus of the material. The thickness of the edge is determined by the natural aging process to reduce the peak residual stress of the edge by 15% to 25%, while retaining the basic distribution of the symmetrical residual stress field formed in step (2), so that the residual stress state of the workpiece is in a pre-adjusted state with low amplitude but favorable distribution when entering the rolling and shaping process.

8. A method for processing a sealing ring assembly for an aero-engine according to claim 1, characterized in that, In step (4), during the rolling and shaping process, a vibration acceleration sensor is installed on the bearing seat of the heavy-duty support roller bearing to collect the vibration signal of the roller in real time during the rolling process. The rolling and shaping process is judged by the trend of the root mean square value (RMS) of the vibration signal: when the relative decrease rate of the RMS value in two consecutive rolling cycles is lower than the preset threshold ε, it is determined that the plastic deformation of the workpiece edge has become stable, and the current number of cycles is the optimal number of rolling cycles to terminate. When the optimal number of rolling cycles to terminate is reached, the rolling is automatically stopped. The preset threshold ε is the threshold of the relative decrease rate of the root mean square value between cycles, which is 5% / cycle to 10% / cycle.

9. A method for processing a sealing ring assembly for an aero-engine according to claim 4, characterized in that, After step (4) is completed, the following precision closed-loop control steps are set: A dial indicator is used to check the overall parallelism of the sealing ring assembly and the gap between the edges; if the detected value exceeds the preset precision threshold, a supplementary compaction strategy is determined based on the deviation Δ: when At that time, control the heavy-duty support roller bearing to add one round of rolling to the workpiece, and the rolling pressure is 80% to 100% of the rolling pressure in the finishing stage of step (4); when At that time, add 2 more passes of rolling, with the rolling pressure being 60% to 80% of the rolling pressure in the finishing stage of step (4); when At that time, add 3 more rolling passes, with the rolling pressure being 70% to 90% of the rolling pressure in the fine rolling stage of step (4); until the test value meets the design requirements.

10. A method for processing a sealing ring assembly for an aero-engine according to claim 1, characterized in that, The roller straightening fixture is fixed in place by clamping it with a vise using a fixed clamping block at the bottom. A deep groove ball bearing is installed between the rotating support and the central shaft as a rotary support pair. A galvanized steel pipe is used as the power input rocker arm, and the manual torque is transmitted to the rotating support through a bearing linkage mechanism, driving the heavy-duty support roller bearing to synchronously achieve the rotary motion around the central shaft and the adjustment of the radial feed. The support ring is fixedly connected to the central shaft, and the outer diameter of the support ring and the inner diameter of the sealing ring assembly are in clearance fit, with the clearance controlled between 0.02mm and 0.05mm. The radial coaxial positioning of the workpiece is achieved through the clearance fit between the inner hole of the workpiece and the outer wall of the support ring. The rolling working surface of the heavy-duty support roller bearing is an arc-shaped surface, and the radius of curvature of the arc-shaped surface matches the radius of curvature of the outer contour of the sealing ring edge, with a radius of curvature deviation ≤0.01mm. The hardness of the working surface of the heavy-duty support roller bearing is ≥HRC50, and the rotation axis of the roller under rolling conditions is perpendicular to the radial direction of the workpiece's central shaft.

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