Annular part subdivision and combination machining method

Abstract

The invention discloses an annular part subdivision and combination machining method, and belongs to the technical field of high-precision annular part manufacturing. The method comprises the steps that an annular blank is preprocessed to form a positioning hole, a ring piece is divided into two semi-rings in the circumferential direction, and then the steps of first-time combined clamping, rough machining, stress releasing, second-time combined clamping, back pulling and locking, fine positioning hole reaming and boring and the like are sequentially carried out. Traditional pressing plate clamping is replaced by backward tensioning of the screws, and stress balance and geometric reconstruction of the ring piece in the machining process are achieved; and the end face finish machining is completed through multiple times of stress release and fractional locking control. According to the method, the multi-stage positioning hole system is combined with the back-pulling locking structure, so that the deformation error of the subdivided ring piece is remarkably reduced, the flatness and the coaxiality of the end face are improved, and the method is suitable for machining high-precision ring parts in the fields of aero-engines, gas turbines and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aircraft engine part machining, in particular to a ring part split and combined machining method. BACKGROUND

[0002] In order to achieve the goal of reducing the cost of the engine, the proportion of parts using forgings as blanks on the aircraft engine is gradually increasing. Taking a typical part, a linkage ring, as an example, the part is fixed on the outside of the casing through evenly distributed adjustable sliding blocks. In order to facilitate assembly and disassembly, the part is usually in the form of a two-half ring structure. The linkage ring bears the centering function in the part and provides support for the rocker arm connected to the guide vane, so the machining precision of the part is very high, and the two-half rings usually need to be combined for machining. In order to reduce the deformation in the machining process, hollow half rings are widely used. The half ring of this profile has high requirements for blank forming control, and the cost of the blank is high, resulting in high cost of the part. In order to reduce the cost of the blank, new engines begin to use forged ring blanks.

[0003] Such parts usually need to be split into two halves and then combined to complete the finishing machining of the inner and outer circles, end faces, and mounting holes. However, after the ring part is split into two halves by wire cutting or other methods, due to the release of residual stress, it often produces large radial deformation and end face warping, making it difficult to reassemble and maintain coaxiality and end face flatness. The existing ring part combined machining method generally uses the following method: first, machining positioning holes on the ring body before splitting, reassembling with positioning pins, then using a pressing plate or other clamping mechanism for fixation, and then machining the combined ring part. However, this method has the following defects: the deformation of the ring part after wire cutting splitting is unpredictable, the original positioning holes often cannot be accurately reused, causing assembly deviation; the pressing plate clamping easily causes uneven stress on the end face during machining, affecting flatness; and the second deformation is not effectively released during finishing machining, which easily causes the superposition of machining stress, resulting in out-of-tolerance roundness and flatness of the finished product.

[0004] Therefore, there is an urgent need for a machining method that can effectively eliminate stress deformation after splitting of a ring part, achieve accurate repositioning, and maintain clamping stability, to ensure the geometric precision and machining consistency of the final combined part.

[0005] CONTENT The present application provides a ring part split and combined machining method to solve the technical problem of poor machining precision caused by stress deformation after splitting of a ring part.

[0006] According to one aspect of the present application, a ring part split and combined machining method is provided, comprising the following steps: pre-machining a ring blank and forming a first positioning hole and a second positioning hole for initial positioning; Cutting the ring part along the circumferential direction into a first half ring and a second half ring, the first positioning hole is located on the first half ring, and the second positioning hole is located on the second half ring; The first half ring and the second half ring are first combined and clamped by using the clamping tool with the first positioning hole and the second positioning hole as the reference, and the inner and outer surfaces of the ring are roughly machined in the constrained state, the third positioning hole is machined on the first half ring, and the fourth positioning hole is machined on the second half ring; The first clamping is released, and the two half rings are subjected to first stress release; The two half rings are second combined and clamped by using the first positioning hole, the second positioning hole, the third positioning hole and the fourth positioning hole, and back tension threaded holes are respectively machined on the first half ring and the second half ring; The two half rings are in a back tension locking state by means of the screws extending from the back of the clamping tool and being screwed into the back tension threaded holes, and the second combined clamping is released; The first positioning hole, the second positioning hole, the third positioning hole and the fourth positioning hole are expanded and bored in the back tension locking state to form a unified fine positioning hole system; The screws are loosened for second stress release, the screws are locked again, and the end faces of the first half ring and the second half ring are finely machined in this state to achieve a predetermined flatness.

[0007] Optionally, one end of the first half ring provided with the first positioning hole is a first end head, and one end of the first half ring provided with the third positioning hole is a third end head, one end of the second half ring provided with the second positioning hole is a second end head, and one end of the second half ring provided with the fourth positioning hole is a fourth end head; The first combined clamping of the first half ring and the second half ring by using the clamping tool with the first positioning hole and the second positioning hole as the reference comprises the following steps: Two first positioning pins are respectively inserted through the first positioning hole and the second positioning hole and matched with the pin holes on the clamping tool, the gap between the first end head and the second end head is detected, and a gap with the same thickness as the detected gap is arranged between the third end head and the fourth end head to ensure that the two half ring cutouts are symmetrical in the circumferential direction; The upper and lower symmetrical points of the two half ring cutouts in the vertical direction are found, the positions of the two half rings are adjusted so that the plane where the cutouts are located passes through the geometric center of the ring, and the vertical line of the cutouts is parallel to the axis of the ring, thereby realizing the vertical symmetry and concentric alignment of the two half ring cutouts.

[0008] Optionally, the second combined clamping of the two half rings by using the first positioning hole, the second positioning hole, the third positioning hole and the fourth positioning hole comprises the following steps: First positioning pins are respectively inserted into the first positioning hole and the second positioning hole, and second positioning pins are respectively inserted into the third positioning hole and the fourth positioning hole; The second positioning pin comprises an upper half segment matched with the third positioning hole and the fourth positioning hole and a lower half segment matched with a pin hole on the clamping tool, and the second positioning pin is divided into several specification groups according to different diameters of the lower half segment; During assembly, the second positioning pin with the largest diameter of the lower half segment that can complete the assembly is inserted into the third positioning hole and the fourth positioning hole to compensate for the hole position offset caused after the splitting and releasing deformation.

[0009] Optionally, the clamping tool comprises a base, and an annular support table for supporting the first half ring and the second half ring is arranged on the base, and a plurality of pin holes for matching with the first positioning pin and the second positioning pin are arranged on the annular support table, and a plurality of clamping pieces for clamping the first half ring and the second half ring are further arranged on the base, and the clamping pieces are used to apply axial clamping force to the two half rings during machining.

[0010] Optionally, the clamping piece comprises a support rod, a clamping plate and a locking rod, the support rod is fixed on the base and is used to support the clamping plate, the locking rod penetrates through the clamping plate in a direction perpendicular to the surface of the workpiece and is threadedly connected with the support rod, and an upper end of the locking rod is provided with a locking nut, when the locking nut is tightened, the clamping plate is pressed towards the upper surface of the workpiece, so that an adjustable clamping force is formed between the clamping plate and the annular support table to fix the first half ring and the second half ring.

[0011] Optionally, in the steps of loosening the screw for the second stress release and locking the screw again, after the second stress release is completed and before the screw is locked again, the following steps are further included: A third positioning pin is inserted into each of the first positioning hole, the second positioning hole, the third positioning hole and the fourth positioning hole, the third positioning pin comprises an upper half segment matched with each positioning hole and a lower half segment matched with a pin hole on the clamping tool, the third positioning pin is divided into several specification groups according to different diameters of the lower half segment, and during assembly, the third positioning pin with the largest diameter of the lower half segment that can complete the assembly is inserted into the corresponding positioning hole.

[0012] Optionally, after the third positioning pin is inserted, all the back-pulling screws are loosened first to make the two half rings in a free release state, then the end portions of the two half rings are tapped in sequence to eliminate residual gaps, and then the back-pulling screws are tightened again under the limitation of the third positioning pin to establish the repositioning state of the two half rings after the second stress release.

[0013] Optionally, one back-pulling screw is arranged at each end of the first half ring and each end of the second half ring, and the four back-pulling screws are symmetrically arranged along the axis of the annular part, and the screw axes of the four back-pulling screws are all parallel to the central axis of the ring part, and the back-pulling screws are used to apply uniform back-pulling force to the two half rings when locked.

[0014] Optionally, after the steps of inserting the self-clamping fixture into the back pull threaded hole by screwing it in, so that the two halves of the ring are in a back pull locked state and the second combination clamping constraint is released, the following steps are also included: semi-finishing the inner circle, outer circle and end face of the ring part, leaving a small amount of allowance for final finishing.

[0015] Optionally, in the step of loosening the screws to perform a second stress release, re-tightening the screws, and then finishing the end faces of the first and second half-rings to achieve a predetermined flatness: each pull screw is tightened in a diagonal sequence, with each tightening torque not exceeding 70% of the final tightening torque; during the tightening process, the gap between the end faces of the two half-rings is monitored and fine-tuned to gradually equalize the residual gap between the end faces; when machining the end faces, the middle area of ​​the ring is machined first, followed by the inner and outer edge areas.

[0016] In summary, this application includes at least one of the following beneficial technical effects: In the processing method of this invention, initial positioning holes are first established before the ring is split, serving as the initial reference for subsequent assembly. This measure ensures that the original geometric features can still be used for the first clamping and shape restoration after splitting. Subsequently, after the initial assembly and clamping, rough machining is performed and new positioning holes are added, allowing the ring to gradually transfer the machining reference under controlled conditions, providing structural conditions for repositioning after splitting deformation. The first stress release is achieved by releasing the clamp, revealing the true deformation caused by splitting and cutting, providing a basis for subsequent correction. In the second assembly stage, a unified precision positioning hole system is formed using four positioning holes for repositioning, and back-pull threaded holes are set. After the back-pull screws are tightened from the back of the tooling, symmetrical tension is applied under conditions without pressure plate interference, so that the two halves of the ring are subjected to balanced force and the assembly is stable. At this time, the hole system is expanded and bored to make the positioning reference consistent with the stable deformation state of the part, realizing the dynamic compensation principle of re-setting the reference after deformation. Finally, the second stress release and re-locking are completed by loosening and tightening the screws again, and the end face is finished in this stable state to eliminate residual machining stress and ensure the final flatness and coaxiality of the ring. This method establishes a closed-loop logic in the process, encompassing initial positioning, rough machining, stress release, repositioning, back-tensioning and locking, further release, and finishing. This avoids the cumulative deformation caused by multiple press-fitting processes and ensures consistency of reference standards and stress balance at each stage. Therefore, this invention can significantly improve the geometric accuracy and assembly consistency of split ring components, providing a reliable processing path for the split manufacturing of high-precision, large-size ring components.

[0017] In addition to the purposes, features, and advantages described above, this application has other purposes, features, and advantages. A further detailed description of this application will be provided below with reference to the figures. Attached Figure Description

[0018] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the structure of the first and second half-rings of this application; Figure 2 This is a cross-sectional view of the clamping fixture used in this application; Figure 3 This is a top view of the clamping fixture used in this application.

[0019] Legend: 1. First half ring; 2. Second half ring; 31. First positioning hole; 32. Second positioning hole; 33. Third positioning hole; 34. Fourth positioning hole; 5. Back pull thread hole; 6. Base; 7. Annular support platform; 8. Support rod; 9. Clamping plate; 10. Locking rod. Detailed Implementation

[0020] The embodiments of this application are described in detail below with reference to the accompanying drawings; however, this application may be implemented in a variety of different ways as defined and covered below.

[0021] The following is in conjunction with the appendix Figures 1-3 This application will be described in further detail.

[0022] Reference Figure 1 This application discloses a method for splitting and assembling a ring-shaped part, comprising the following steps: S100, pre-process the annular blank to form a first positioning hole 31 and a second positioning hole 32 for initial positioning; S200, the annular part is cut into a first half-ring 1 and a second half-ring 2 along the circumferential direction, so that the first positioning hole 31 is located on the first half-ring 1 and the second positioning hole 32 is located on the second half-ring 2. S300: Using a clamping fixture, the first half-ring 1 and the second half-ring 2 are initially combined and clamped with the first positioning hole 31 and the second positioning hole 32 as references. The inner and outer surfaces of the ring are roughed under the constraint state. The third positioning hole 33 is machined on the first half-ring 1 and the fourth positioning hole 34 is machined on the second half-ring 2. S400, release the initial clamping to allow the two halves of the ring to release stress for the first time; S500, the two half rings are combined and clamped for the second time using the first positioning hole 31, the second positioning hole 32, the third positioning hole 33 and the fourth positioning hole 34, and back pull thread holes 5 are machined on the first half ring 1 and the second half ring 2 respectively. S600, by inserting the screw into the back threaded hole 5 of the self-clamping fixture through the back, the two half rings are in a back-pull locking state, and the second combination clamping constraint is released. S700, in the back-pull locking state, the first positioning hole 31, the second positioning hole 32, the third positioning hole 33 and the fourth positioning hole 34 are enlarged and bored to form a unified precision positioning hole system; S800, loosen the screw to release stress for the second time, tighten the screw again, and in this state, perform finishing on the end faces of the first half ring 1 and the second half ring 2 to achieve the predetermined flatness.

[0023] Step S100 is completed in the overall state of the ring component. At this time, the residual stress of the component has not yet been released, and the structure is stable, thus obtaining a high-precision initial positioning hole system. By establishing a positioning datum in the overall state, it can be ensured that the two halves of the ring are still referenced to the original geometric center when they are reassembled after splitting, avoiding assembly datum drift caused by deformation after splitting.

[0024] This initial positioning hole serves as the reference starting point for the subsequent multi-stage positioning system and is the core control basis of the entire process.

[0025] The purpose of step S200 is to provide an open structure for subsequent machining of the inner and outer surfaces and end faces, while controlling the residual stress release path by defining the cutting direction. After cutting, the ring body undergoes a certain radial opening or closing deformation, reflecting the distribution of internal stress in the material. The positioning holes retained on the two halves of the ring during this process ensure the traceability of the geometric datum after part splitting, providing a precise reference for subsequent reassembly.

[0026] The key to step S300 lies in machining under constrained conditions and datum expansion. The split ring is positioned using a clamping fixture, restoring the two halves to near-integral roundness, and free deformation is suppressed through controlled clamping. Rough machining in this state removes most of the excess material and initially balances the internal and external stresses of the two halves. Subsequently, the third and fourth positioning holes 34 are formed during machining, expanding the positioning datum from a two-hole system to a four-hole system, constructing a highly stable positioning structure with over-constraint compensation capabilities. This provides the necessary geometric datum conditions for subsequent deformation release and repositioning.

[0027] The purpose of step S400 is to fully release the residual stress generated by splitting and rough machining, allowing the part shape to tend towards a natural deformation state. Unlike traditional continuous clamping machining, this invention intentionally removes constraints at this stage to obtain the true deformation trend of the workpiece, thereby providing an actual morphological reference for the next positioning step and avoiding the cumulative errors caused by "stressed machining" in subsequent processing.

[0028] Step S500 achieves high-degree-of-freedom recombination through four-point positioning, enabling the two halves of the ring to be accurately reset under multiple reference conditions.

[0029] The back tension threaded hole 5 is set as an interface for subsequent reverse tensioning. Its arrangement corresponds to the hole system, which can ensure that the assembly force is applied evenly and avoid end face warping caused by local force.

[0030] Step S600 uses the axial tension of the pull screws to create a self-constraining structure between the two halves of the ring, achieving stable bonding of the workpiece without interference from external pressure plates. This avoids the uneven force field problem caused by traditional pressure plate clamping in the machining area, making the machining area completely open and creating conditions for high-precision hole machining.

[0031] Step S700, by performing finishing machining on the hole system when the ring component has achieved back-to-back balance constraint and the stress is in a stable state, ensures that the final hole positions are completely consistent with the actual deformation state of the part. This method guarantees the authenticity and stability of the final assembly datum.

[0032] Step S800 uses a cycle of tightening and loosening to release and rebalance residual stress, minimizing stress in the ring component during final machining. Subsequent end-face finishing under balanced constraints effectively prevents springback or warping after machining, ensuring that the flatness of the end face and the coaxiality between the two halves of the ring meet design requirements.

[0033] Steps S100 to S800 in this embodiment form a complete machining closed loop, sequentially realizing full-process control from initial positioning, stress manifestation, repositioning to final finishing. The core of this method lies in establishing an initial geometric datum before the ring part deforms and redefining the machining datum after deformation release, ensuring that the assembly positioning always remains consistent with the actual shape of the part; by transforming external clamping into internal back-pull locking, symmetrical and balanced force on the ring part is achieved, avoiding end-face warping and force deviation caused by pressure plate clamping; simultaneously, through double stress release and dynamic repositioning, the part is in a stress equilibrium state during final machining, fundamentally guaranteeing the geometric stability and dimensional accuracy of the finished product. Therefore, this invention can significantly improve the assembly consistency, end-face flatness, and roundness accuracy of segmented ring parts, and is particularly suitable for the split machining and assembly manufacturing of large-diameter, high-precision ring parts.

[0034] In one embodiment, to ensure that the two half-rings can be restored to a near-original geometric shape during the initial clamping and assembly, this embodiment further optimizes the clamping and alignment process. The end of the first half-ring 1 with the first positioning hole 31 is defined as the first end, and the end with the third positioning hole 33 is defined as the third end; the end of the second half-ring 2 with the second positioning hole 32 is defined as the second end, and the end with the fourth positioning hole 34 is defined as the fourth end. The clamping fixture is provided with pin holes that mate with the first positioning hole 31 and the second positioning hole 32. During the initial assembly, the first positioning pins are inserted into the two holes respectively, establishing a preliminary fit between the two half-rings in the circumferential direction. Subsequently, the gap between the first and second ends is measured, and a feeler gauge or shim of equal thickness to the gap is added between the third and fourth ends to form geometric symmetry compensation. This compensation operation can adjust the opening degree of the rings by using equal-thickness shims when there is slight opening or closing deformation in the rings, thereby ensuring that the cuts of the two half-rings remain symmetrical in the circumferential direction.

[0035] After achieving circumferential symmetry, the vertical symmetrical points of the two half-ring cuts are aligned to ensure the plane containing the cuts passes through the geometric center of the ring, and the line connecting the vertical cuts is parallel to the ring's axis. This alignment ensures the radial perpendicularity and concentricity of the split interface, allowing the ring to return to near-original roundness after the initial assembly, providing geometric assurance for subsequent rough machining. Through this composite positioning method based on gap adjustment and vertical alignment, precise fit between the two half-rings is achieved, ensuring subsequent rough machining is performed under symmetrical force conditions, effectively reducing roundness deviations and end-face tilting caused by clamping errors. By combining the positioning datum with the geometric adjustment process, concentric alignment and form-position correction of the split ring are achieved during the initial assembly stage. This method significantly improves the datum stability and symmetry of subsequent machining stages.

[0036] In one embodiment, to further improve the reassembly accuracy of the split ring and compensate for the hole position offset caused by the first stress release, this embodiment employs a four-point positioning structure during the second assembly clamping. In the second assembly stage, first positioning pins are inserted into the first positioning hole 31 and the second positioning hole 32, respectively, and second positioning pins are inserted into the third positioning hole 33 and the fourth positioning hole 34, respectively.

[0037] The second locating pin is designed in a segmented manner, with the upper segment engaging with the third and fourth locating holes 34, and the lower segment engaging with the pin hole on the clamping fixture. Several sets of second locating pins are prefabricated according to the different diameters of their lower segments to accommodate minor deviations in hole position caused by ring deformation. During assembly, by measuring the minute difference in hole spacing between the two half-rings in their free state, the second locating pin with the largest lower segment diameter suitable for assembly is selected for insertion. This selective engagement proactively compensates for hole offset, allowing the two half-rings to automatically align within a minimal floating gap when the pin is inserted. This positioning strategy prioritizing the largest configurable diameter ensures the stability of the pin-hole engagement while avoiding localized compressive stress caused by forced assembly.

[0038] Through the combined constraint of four positioning holes, the ring component achieved an upgrade from two-point support to multi-point positioning during the second assembly, and its overall attitude was recorrected. Compared to the initial assembly stage which relied on only two holes for positioning, this embodiment, with its four-hole system, can simultaneously restrict the ring component's translational, tilting, and radial rotational degrees of freedom, making the geometric center of the assembled ring component closer to the original center before dissection. The core of this operation lies in allowing the ring component to complete the second datum reconstruction while its deformation has been released, thereby establishing a new positioning system that matches its actual shape.

[0039] In one embodiment, to further improve the positioning accuracy of the ring after stress relief and ensure that the final machining datum is consistent with the stable shape of the part, this embodiment adds a step of inserting a third locating pin after the second stress relief and before tightening the back pull screw again. The structure of the third locating pin is similar to that of the aforementioned second locating pin, also including an upper half and a lower half. The upper half is used to precisely mate with the first to fourth locating holes 34 of the ring, and the lower half is used to mate with the corresponding pin holes on the clamping fixture. To accommodate possible slight hole displacement after stress relief, the third locating pin is prefabricated in several specification groups according to the different diameters of the lower half.

[0040] In practice, by measuring the hole spacing difference after stress relief, a third locating pin with the largest lower diameter is selected to be inserted into the corresponding hole, allowing for smooth insertion and achieving a transition fit between the pin and the hole under minimal clearance conditions. The main benefits of this step are as follows: First, the re-insertion of the third locating pin allows the ring to obtain a new constraint reference under its natural deformation state after the second stress relief, avoiding forced positioning errors that might be caused by directly tightening the screw.

[0041] After the third locating pin is inserted for fine positioning, to further eliminate residual gaps between the two halves of the ring and achieve final stable positioning, this embodiment performs a composite correction operation of loosening, fine-tuning, and re-locking based on the fine positioning. After the third locating pin is inserted, all the back pull screws are first loosened, releasing the two halves of the ring from the locking constraint and placing them in a completely free state. At this time, the ring can be slightly adjusted under the limiting guidance of the third locating pin, thereby eliminating minor misalignment of the holes caused by residual locking force. Subsequently, the operator gently taps or applies a small impact along the symmetrical parts of the ends of the two halves of the ring to rebalance the contact state of the end faces. This tapping process utilizes the elastic recovery characteristics of the material, allowing the ring to automatically align under the constraint of the third locating pin, achieving self-balancing of the end face mating gap. After fine-tuning, while maintaining the limiting state of the third locating pin, the back pull screws are retightened in a diagonal sequence to gradually restore the locking force to the design value. This diagonal alternating locking method ensures that the locking force is evenly distributed in the circumferential direction of the ring, avoiding torsional deformation caused by locking on one side first. When all the back pull screws are tightened, the ring enters a state of mechanical equilibrium, forming a dual-stable combination where the geometric position is controlled by the third locating pin and the axial clamping force is provided by the screws.

[0042] In one embodiment, to ensure balanced force on the ring member and maintain consistency in the axial direction under the back-pull locking state, the arrangement and function of the back-pull screws are optimized. Four back-pull screws are provided, installed at both ends of the first half-ring 1 and the second half-ring 2, respectively, symmetrically arranged along the circumference of the ring member. The axis of each screw is parallel to the central axis of the ring member and distributed at equidistant positions on both sides of the ring member's axis, so that the axial tension force generated during locking is spatially mirror-symmetrical.

[0043] This symmetrical arrangement allows the axial forces on the two halves of the ring to cancel each other out when the pull screws are tightened, thus creating an overall balanced state. Unlike the traditional single-sided pressure plate locking method, the pull screws do not generate direct compressive stress on the upper surface of the ring when under force; instead, they create a reverse tension through the internal threaded holes. This internal tension constraint provides linear and controllable axial tension during the tightening process, ensuring that the two halves of the ring maintain uniform contact along the circumference, significantly reducing end face warping and local deformation. In actual operation, the four screws are tightened sequentially in a diagonal order, allowing the tightening force to be gradually transferred from one side to the symmetrical side, avoiding unbalanced forces caused by locking one side first. After tightening, the inner and outer rings of the ring are in a bidirectional constraint state, with both the geometric reference constraint provided by the third locating pin and the mechanical balance constraint provided by the pull screws, thus forming a rigid closed system. This system maintains end face contact while allowing for minor elastic deformation compensation, ensuring simultaneous control of end face flatness and roundness accuracy.

[0044] To further improve the geometric stability and final machining accuracy of the ring component, this embodiment performs semi-finishing on the ring component at this stage. The semi-finishing process includes the inner circle, outer circle, and end face of the ring component, with a small allowance retained during the machining process for dimensional correction and form and position compensation during subsequent finishing.

[0045] Because the split ring component has undergone two stress releases and multiple clamping operations in the early stages, although its internal residual stress has been significantly reduced, local non-uniform distribution may still exist. Directly performing final finishing can easily cause slight deformation due to the combined effects of cutting force and temperature rise, affecting the final dimensional accuracy. Therefore, semi-finishing under back-tension and locking conditions is a stabilizing cutting process. Its purpose is to further release micro-stress while maintaining clamping balance, allowing the part to gradually solidify its geometric shape.

[0046] In the semi-finishing stage, the cutting allowance is typically controlled within a small range to ensure low machining forces and heat input, avoiding disruption of the current balanced clamping state. This light cutting operation simultaneously corrects dimensional and positional deviations left over from the roughing stage and ensures the machined surface of the ring is completely aligned with the back-tightening locking datum. After machining, the inner and outer roundness and end face flatness of the ring are close to design requirements, requiring only a small allowance to proceed to the final finishing stage. Furthermore, this step also serves as a process buffer: after semi-finishing, the operator can measure and inspect the ring to determine if the locking torque distribution is balanced and if the end faces align consistently. If micro-gaps are found in certain areas of the end faces, they can be corrected immediately by fine-tuning the torque of a single screw without reclamping. This pre-inspection and torque correction during the semi-finishing stage significantly reduces the risk in the final finishing stage, ensuring the controllability of the finished product's geometric accuracy.

[0047] After completing the semi-finishing and confirming that the ring is in a stable clamping state, the final finishing stage of the end face begins. This stage uses pull screws as the main constraint element, in conjunction with the limiting effect of the third locating pin. By controlling the tightening sequence and cutting path, high flatness and overall dimensional accuracy of the end face are achieved. In specific operations, the four pull screws are first tightened in a diagonal sequence. Each tightening torque is controlled at approximately 70% of the final target torque, ensuring that the ring initially forms an elastic preload rather than a rigid constraint, thus avoiding end face warping or asynchronous deformation of the inner and outer rings due to excessive tightening in a single operation. During the tightening process, the gap between the two half-ring end faces is monitored in real time using a feeler gauge or displacement sensor. If necessary, the tightening amount of individual screws is fine-tuned to gradually equalize the residual gap between the end faces. When the gaps at all points tend to be consistent, the screws are then tightened sequentially to the final torque, allowing the ring to reach a stable state under balanced stress.

[0048] The cutting sequence for end face finishing adopts a process route from the inside out or from the center to the edge. That is, the central area of ​​the ring is machined first, and then gradually extended to the inner and outer edges. This machining sequence can effectively disperse the cutting force and avoid the elastic rebound of the ring caused by machining the outer ring first, thereby suppressing end face warping. At the same time, the cutting allowance is small and the feed rate is moderate to maintain low cutting force and low heat input, ensuring that stress changes are minimized during machining.

[0049] After finishing, the flatness of the end face and the coaxiality of the two halves of the ring were inspected. The inspection results showed that the end face flatness of the ring processed using this method was significantly better than that of the traditional clamping method. This result indicates that the stress control strategy of multiple locking and real-time fine adjustment can ensure that the end face processing is always carried out in a state of mechanical equilibrium, thereby achieving a highly stable and repeatable processing effect.

[0050] Reference Figure 2 and Figure 3 In one embodiment, to ensure stable clamping and reliable positioning of the split ring component at each processing stage, this embodiment provides a clamping fixture structure suitable for this method. The clamping fixture includes a base 6, an annular support platform 7, and several functional holes for mounting positioning pins and clamping components. The base 6 is an integral rigid platform structure used to bear the first half-ring 1 and the second half-ring 2 and the clamping force they experience. The annular support platform 7 is disposed on the upper surface of the base 6, and its circumferential arrangement is coaxial with the geometric center of the ring component, forming an annular support surface for supporting the lower end face of the ring component.

[0051] The support platform is provided with a number of pin holes evenly distributed along the circumference, which are used to mate with the first positioning hole 31, the second positioning hole 32, the third positioning hole 33, and the fourth positioning hole 34 to insert positioning pins. This pin hole array structure enables multi-point combination positioning and repeatable positioning accuracy control, thereby ensuring the positional consistency of the ring component during multiple clamping processes. On the outer side or radially spaced area of ​​the annular support platform 7, a number of clamping component mounting holes are also provided for installing clamping mechanisms that apply axial clamping force. During operation, the clamping components press downwards against the upper surface of the workpiece through threaded connections or locking structures, forming a stable clamping system between the support platform and the clamping components.

[0052] In one embodiment, to achieve stable clamping and adjustable pressing of the annular part during processing, the clamping component in this embodiment comprises three parts: a support rod 8, a clamping plate 9, and a locking rod. The support rod 8 is vertically fixedly installed on the base 6 and is the core load-bearing component of the clamping structure. Its upper end supports the clamping plate 9, and its lower end is connected to the base 6 via threads or welding to ensure overall rigidity and stability for repeated use. The clamping plate 9 is arranged laterally above the support rod 8, with its lower surface facing the upper end face of the annular part, forming a clamping contact surface. A locking rod is provided above the clamping plate 9, passing through the clamping plate 9 in a direction perpendicular to the workpiece end face and forming a threaded connection with the support rod 8. A locking nut is provided at the upper end of the locking rod. When the nut is tightened, the locking rod moves axially downwards, pushing the clamping plate 9 downwards, thereby applying a controllable clamping force to the workpiece between the annular support platform 7 and the clamping plate 9.

[0053] This structural design offers the following technical advantages: The locking rod and support rod 8 utilize a threaded drive, enabling linear adjustment of the clamping force. Operators can flexibly control the clamping strength based on the ring material and processing stage, preventing localized plastic deformation caused by excessive clamping. The contact surface between the clamping plate 9 and the ring can be designed as a flat or slightly curved surface to achieve uniform distribution of clamping force on the ring's end face, ensuring force balance under clamping conditions. The clamping elements can be arranged circumferentially along the base 6, forming a multi-point symmetrical clamping system, thus maintaining the mechanical symmetry of the workpiece along its axis during clamping and preventing end face warping. Compared to traditional clamping methods using pressure plates and pads, this embodiment achieves a repeatable and finely adjustable clamping structure through the cooperation of the support rod 8 and the locking rod.

[0054] The implementation principle of the ring part splitting and assembly machining method in this application is as follows: Before splitting the ring part, the overall geometric datum is determined through the initial positioning holes. After cutting, the positioning datum is transferred at different stages using a multi-hole system, ensuring that the assembly reference during machining always remains consistent with the actual shape of the workpiece. In terms of mechanical control, through two stress releases and symmetrical locking with back-pull screws, the stress field of the ring part is gradually balanced during machining, so that residual stress is fully released before cutting, uniformly constrained during cutting, and no longer springs back after cutting. The essence of this method is to transform the traditional rigid machining mode of fixed datum and forced clamping into a flexible control mode with reconfigurable datum and adjustable constraints. Through the above principles, this invention not only improves the roundness, flatness, and coaxiality accuracy of split ring parts, but also realizes the accuracy transfer and form and position consistency control of the entire process from splitting and assembly to finished product machining, which can significantly improve machining quality and dimensional stability without increasing clamping complexity.

[0055] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for splitting and assembling ring-shaped parts, characterized in that, Includes the following steps: The annular blank is pre-machined to form a first positioning hole (31) and a second positioning hole (32) for initial positioning; The ring-shaped part is cut into a first half-ring (1) and a second half-ring (2) along the circumferential direction, so that the first positioning hole (31) is located on the first half-ring (1) and the second positioning hole (32) is located on the second half-ring (2); Using a clamping fixture, the first half ring (1) and the second half ring (2) are first combined and clamped with the first positioning hole (31) and the second positioning hole (32) as references. The inner and outer surfaces of the ring are rough machined under the constraint. The third positioning hole (33) is machined on the first half ring (1) and the fourth positioning hole (34) is machined on the second half ring (2). Release the initial clamping to allow the two halves of the ring to release stress for the first time; The two halves of the ring are clamped together for the second time using the first positioning hole (31), the second positioning hole (32), the third positioning hole (33) and the fourth positioning hole (34), and back pull thread holes (5) are machined on the first half ring (1) and the second half ring (2) respectively. By inserting the screw self-clamping fixture into the back pull threaded hole (5) from the back, the two half rings are in a back pull locked state, and the second combination clamping constraint is released. In the back-pull locking state, the first positioning hole (31), the second positioning hole (32), the third positioning hole (33) and the fourth positioning hole (34) are enlarged and bored to form a unified precision positioning hole system; Loosen the screws to release the stress for the second time, tighten the screws again, and in this state, finish the end faces of the first half ring (1) and the second half ring (2) to achieve the predetermined flatness.

2. The method for splitting and assembling ring-shaped parts according to claim 1, characterized in that: The first half-ring (1) has a first positioning hole (31) at one end as the first end and a third positioning hole (33) at the other end as the third end; the second half-ring (2) has a second positioning hole (32) at one end as the second end and a fourth positioning hole (34) at the other end as the fourth end. The initial combination clamping of the first half-ring (1) and the second half-ring (2) using the clamping fixture with the first positioning hole (31) and the second positioning hole (32) as references includes the following steps: Two first positioning pins are passed through the first positioning hole (31) and the second positioning hole (32) respectively and engaged with the pin holes on the clamping fixture. The gap between the first end and the second end is detected, and a pad gap of the same thickness as the detected gap is set between the third end and the fourth end to ensure that the two half ring cuts are symmetrical in the circumferential direction. Find the vertical symmetrical points of the two half-ring cuts. By adjusting the positions of the two half-rings, make the plane where the cuts are located pass through the geometric center of the ring and make the line connecting the vertical directions of the cuts parallel to the axis of the ring, thereby achieving vertical symmetry and concentric alignment of the two half-ring cuts.

3. The method for splitting and assembling ring-shaped parts according to claim 2, characterized in that: The second combination clamping of the two halves of the ring using the first positioning hole (31), the second positioning hole (32), the third positioning hole (33), and the fourth positioning hole (34) includes the following steps: Insert the first positioning pin into the first positioning hole (31) and the second positioning hole (32) respectively, and insert the second positioning pin into the third positioning hole (33) and the fourth positioning hole (34) respectively; The second positioning pin includes an upper half that mates with the third positioning hole (33) and the fourth positioning hole (34) and a lower half that mates with the pin hole on the clamping fixture. The second positioning pin is divided into several specification groups according to the different diameters of the lower half. During assembly, the second locating pin with the largest diameter of the lower half that can complete the assembly is inserted into the third locating hole (33) and the fourth locating hole (34) to compensate for the hole position offset caused by the splitting and release deformation.

4. The method for splitting and assembling ring-shaped parts according to claim 1, characterized in that: The clamping fixture includes a base (6), on which an annular support platform (7) is provided for supporting the first half ring (1) and the second half ring (2). The annular support platform (7) is provided with a number of pin holes for cooperating with the first positioning pin and the second positioning pin. The base (6) is also provided with a number of clamping parts for clamping the first half ring (1) and the second half ring (2) to apply axial clamping force to the two half rings during the processing.

5. The method for splitting and assembling ring-shaped parts according to claim 4, characterized in that: The clamping components include a support rod (8), a clamping plate (9), and a locking rod. The support rod (8) is fixed on the base (6) to support the clamping plate (9). The locking rod passes through the clamping plate (9) in a direction perpendicular to the workpiece surface and is threadedly connected to the support rod (8). The upper end of the locking rod is provided with a locking nut. When the locking nut is tightened, the clamping plate (9) is pressed against the upper surface of the workpiece, thereby forming an adjustable clamping force between the clamping plate (9) and the annular support platform (7) to fix the first half ring (1) and the second half ring (2).

6. The method for splitting and assembling ring-shaped parts according to claim 1, characterized in that: The step of loosening the screw for a second stress release and then tightening the screw again includes the following step after the second stress release is completed and before tightening the screw again: A third positioning pin is inserted into the first positioning hole (31), the second positioning hole (32), the third positioning hole (33), and the fourth positioning hole (34). The third positioning pin includes an upper half that mates with each positioning hole and a lower half that mates with the pin hole of the clamping tool. The third positioning pin is divided into several specification groups according to the different diameters of the lower half. During assembly, the third positioning pin with the largest diameter of the lower half that can achieve assembly is selected and inserted into the corresponding positioning hole.

7. The method for splitting and assembling ring-shaped parts according to claim 6, characterized in that: After inserting the third locating pin, first loosen all the back pull screws to allow the two half rings to be in a free state. Then, gently tap the ends of the two half rings one by one to eliminate any residual gaps. Finally, under the limit of the third locating pin, tighten the back pull screws again to establish the repositioning state of the two half rings after the second stress release.

8. The method for splitting and assembling ring-shaped parts according to claim 7, characterized in that: One back pull screw is provided at each end of the first half ring (1) and one at each end of the second half ring (2). The four back pull screws are arranged symmetrically along the axis of the ring part, and their screw axes are all parallel to the central axis of the ring part. They are used to apply a uniform back tension force to the two half rings when locking.

9. The method for splitting and assembling ring-shaped parts according to claim 8, characterized in that: After the steps of inserting the screw self-clamping fixture into the back pull threaded hole (5) to put the two half rings in the back pull locking state and releasing the second combination clamping constraint, the following steps are also included: semi-finishing the inner circle, outer circle and end face of the ring part, and retaining a small amount of allowance for final finishing.

10. The method for splitting and assembling ring-shaped parts according to claim 9, characterized in that: In the steps of loosening the screw to release stress for the second time, tightening the screw again, and then finishing the end faces of the first half-ring (1) and the second half-ring (2) to achieve the predetermined flatness: Each pull screw should be tightened in a diagonal sequence, with each tightening torque not exceeding 70% of the final tightening torque. During the locking process, the gap between the two half-ring end faces is monitored and fine-tuned to gradually equalize the residual gap between the end faces; When machining the end face, first machine the middle area of ​​the ring, and then machine the inner and outer edge areas.

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