CN117655677A

CN117655677A - Machining method of asymmetric rear support ring of aero-engine

Info

Publication number: CN117655677A
Application number: CN202311854794.3A
Authority: CN
Inventors: 赵朝刚; 韩威; 王智
Original assignee: Wuxi Hyatech Technology Co ltd
Current assignee: Wuxi Hyatech Technology Co ltd
Priority date: 2023-12-29
Filing date: 2023-12-29
Publication date: 2024-03-08

Abstract

The invention provides a processing method of an asymmetric rear support ring of an aero-engine, which can solve the problems of large part deformation, easy out-of-tolerance of shape and position dimensions, complex processing tool and long manufacturing period of the existing rear support ring processing method. Which comprises the following steps: blank size rechecking, trimming, milling a joint surface, combining, rough turning two ends and a molded surface, rough milling an inner shape, removing stress heat treatment, splitting, trimming a large end standard, finish milling a longitudinal installation edge and an installation hole, combining, trimming a small end standard, semi-finish turning a large end/small end, semi-finish milling an inner shape, stabilizing, finish turning a large end, finish milling a small end, finish milling a large end, finish trimming a large end, finishing a small end hole, turning a process table, milling a large end groove and a hole, splitting, finish milling a joint surface, clamping and trimming, fluorescent penetration inspection and final inspection.

Description

Machining method of asymmetric rear support ring of aero-engine

Technical Field

The invention relates to the technical field of machining of aero-engine parts, in particular to a machining method of an asymmetric rear support ring of an aero-engine.

Background

The rear support ring is a structural member which is separated from the rear end of the intermediate case unit body of the aeroengine, wherein one of the rear support ring is made of the following materials and has the structural parameters: the material is 2618 aluminum alloy, the diameter is 1730mm, the height is 289mm, the minimum wall thickness is 5mm, and the material is a typical large-sized thin-wall split type structural member, and is processed by adopting forging blanks of solid solution and aging. The parts are two semi-ring parts with asymmetric structures, and besides the same turning radius and height, the number and positions of bosses, the shape and positions of oval windows, the distribution positions and sizes of holes and the sizes and shapes of grooves at the upper end and the lower end have certain difference on the two semi-rings; the circumference angle of the two semi-rings is also asymmetric, one side of one semi-ring exceeds the 180-degree central plane by 10mm, the other two ends of the other semi-ring are respectively 12mm and 23mm away from the 180-degree central plane, and the two semi-ring parts are connected through two connecting plates inserted between the two semi-ring parts to form a complete supporting ring assembly through bolts during assembly.

The 2618 aluminum alloy is an aluminum-copper-magnesium-iron-nickel alloy which can be strengthened by heat treatment, has higher heat resistance and better cold and hot processing performance, and is suitable for manufacturing parts used at higher temperature. However, this material has a relatively high coefficient of thermal expansion and is easily deformed during thin-wall processing. In addition, the parts are basically ring-forged integral blanks in the research and development stage, and the internal stress of the blanks is very large; in the processing process, because the allowance is large, the material is free-cutting, and higher cutting parameters can be selected for improving the efficiency, more cutting heat is generated, the processing stress is increased, and the parts are easy to deform greatly after being processed. These factors may cause serious deviations in the dimensions of the subsequent processes or the final form and location.

For thin-wall asymmetric semi-ring parts such as rear supporting rings, a common and economical machining mode is to adopt an integral ring forging piece, adopt linear cutting and cutting after rough machining, then connect the integral ring forging piece with bolts according to the machining mode of split casing parts, finally cut according to design requirements, and finish-machine a cutting surface to obtain a final product. However, because the internal stress of the aluminum alloy ring forging is very large, the deformation of the wire cutting part after rough machining is very large (the shrinkage of the opening can reach 40 mm), and the radial shrinkage of the opening parts of the two half rings is not consistent; meanwhile, due to the difference of the structure and the thickness, the radial deformation of the semi-annular cutting surface along the height direction is inconsistent, so that the reserved allowance of rough machining can not cover the deformation of the part far, the subsequent process can not be carried out, and even scrapping is generated.

Disclosure of Invention

Aiming at the problems of large part deformation and difficult dimensional accuracy guarantee of the existing back support ring processing method, the invention provides the processing method of the asymmetric back support ring of the aero-engine, the deformation of the processing process is controllable, and the processing accuracy meets the design requirement.

The technical scheme is as follows: a processing method of an asymmetric rear support ring of an aero-engine comprises the following steps: the method is characterized in that the annular part is split into two semi-annular parts in half during the blank processing, and then the two semi-annular parts are subjected to subsequent processing; before rough machining, connecting the two semi-ring parts into an integral annular part for machining, after rough milling, carrying out stress relief heat treatment on the integral annular part formed by connecting the two semi-ring parts, then splitting and trimming the integral annular part, reconnecting the integral annular part into an integral annular part, establishing a semi-finishing reference, and carrying out machining according to the semi-finishing reference during semi-finishing.

Further, the method specifically comprises the following steps: 1. machining a blank; the annular part is split into two semi-annular parts, each semi-annular part comprises a large end and a small end which are positioned at two ends of the semi-annular part, the diameter of the large end is larger than that of the small end, and the inner part of the large end is in a step shape;

2. rechecking the blank size; measuring the size of the semi-ring part, ensuring that enough allowance is reserved on each machining surface, and checking the surface quality of the part;

3. repairing a standard; bonding the joint surfaces of the two semi-ring parts to form a circular ring shape in a free state, positioning the small end and pressing the step surface of the part, and turning the end surface of the large end for positioning;

4. milling a joint surface; positioning by using the end face of the large end, leveling the planes of the joint surfaces at the left side and the right side, compacting the small end of the part after centering the center of the half ring, rough milling the inner circle of the small end, combining the longitudinal installation edge formed by extending towards the outside of the part, and processing the connecting hole and the positioning pin hole on the longitudinal installation edge;

5. combining; the two semi-ring parts are fixedly connected through the machined connecting holes by using the connecting piece to form an integral ring part;

6. rough turning two ends and molded surfaces; when the small end is roughly turned, positioning and clamping the large end of the combined circular part, roughly turning the small end and the outer molded surface of the circular part, and removing part of the allowance; when the large end is roughly turned, positioning and clamping are carried out by using the small end of the combined circular ring part, the large end and the inner molded surface of the circular ring part are roughly turned, partial allowance is removed, and a large end process step is processed at the outer molded surface of the large end;

7. rough milling of inner and outer profiles; positioning by using a large end face and an inner hole, compacting the large end process step, and rough milling an inner contour and an outer contour;

8. stress-relieving heat treatment; carrying out heat treatment on the combined circular ring part to remove internal stress of the part after rough machining;

9. splitting; removing the connecting piece to split the ring part into two semi-ring parts;

10. repairing a large end reference; bonding the joint surfaces of the two semi-ring parts to form a circular ring shape in a free state, positioning and compacting the joint surfaces by using a small end, and turning the end surface of a large end and a positioning step;

11. finish milling the joint surface; positioning by using the end face of the large end and a positioning step, and finely milling the longitudinal mounting edge, the connecting hole on the longitudinal mounting edge and the positioning pin hole after pressing the upper surface of the large end process step;

12. combining; the two semi-ring parts are fixedly connected through the machined connecting holes by using the connecting piece to form an integral ring;

13. repairing a small end reference; positioning by using a large end face, compacting on the upper surface of a large end process step, and finely turning the small end face and the inner circle of a small end spigot by taking the center of the assembly as a reference after the center is redetermined;

14. semi-finish turning the profile of the large end and the small end; positioning the inner cylindrical surface of the spigot and the small end face, semifinish turning the large end molded surface, positioning the large end face and the large end inner cylindrical surface, compacting from the upper surface of the large end process step, and semifinish turning the small end molded surface;

15. semi-finish milling of inner and outer profiles; positioning by using a large end face and an inner hole, pressing the upper surface of a large end process step, and semi-finish milling the inner and outer profiles;

16. stabilizing treatment; performing stable heat treatment on the combined circular ring part, and removing internal stress of the semi-finished part;

17. finish turning the large end; positioning the inner cylindrical surface of the spigot and the end face of the small end, finely turning the large end, reserving a certain margin for subsequent processing, and reserving a large end process step;

18. finely turning the small end; positioning the inner cylindrical surface of the spigot and the end face of the large end, finely turning the end face of the small end and the inner and outer cylinders, and reserving a certain margin for subsequent processing;

19. finish milling of the small end profile; positioning by using a large end face and a large end inner hole, compacting the upper surface of a process step, and finish milling the outline near the small end;

20. finish milling of the large end profile; turning over the part with the finish-milled small end, installing a clamp, positioning the end face and the inner hole of the small end, compressing along the upper side of the installation edge of the small end, and finish-milling the outline near the large end;

21. finishing a small end reference; positioning the large end face and the large end inner hole, pressing the upper surface of the technological step, and processing and removing allowance on the small end face and the inner and outer circles to obtain the final size;

22. finishing a large end reference; positioning the inner cylindrical surface of the spigot and the end face of the small end, compacting by utilizing the back surface of the mounting edge of the small end, finely turning the end face of the large end to ensure the total height to the final size and the requirement on parallelism, and finely turning the inner molded surface to the final size;

23. finish milling of small end holes; positioning the finished large end face and inner hole, compacting the large end process step, supporting the internal auxiliary support of the part, and processing after aligning the small end inner circle runout of not more than 0.03 mm;

24. turning a process table; positioning the inner cylindrical surface of the spigot and the end face of the small end, compacting by using the surface of the mounting edge of the small end, and finely turning the outer circle of the process table of the large end and the surface of the mounting edge of the large end to the final size;

25. finish milling of the large end groove and the hole;

26. splitting; removing the connecting piece to split the ring part into two semi-ring parts;

27. finish milling the joint surface; positioning the small end of the semi-ring part upwards, pressing the small end of the semi-ring part on the upper surface of the large end mounting edge and the large end reinforcing rib by using the large end surface and the large end thin-wall straight-side inner hole, firstly milling the longitudinal mounting edge, and then finish milling the notch to the required shape and angle;

28. clamping; removing surface defects;

29. performing fluorescence penetration inspection; the surface of the part is inspected, if the defect exists, the procedure is returned to the upper procedure for reworking, and the fluorescent penetration inspection is performed again;

30. and (3) final inspection: and detecting the size and the surface quality of the part, and meeting the design drawing and specification of the support ring.

Further, in step 6, the part is uniformly spaced apart in the radial direction Amm and in the height direction Bmm, A being greater than B.

Furthermore, in step 7, step 15 and step 19, when the profile of the outer shape is milled, an adjustable flexible auxiliary support which is consistent with the profile is added on the inner shape to increase the rigidity of the part, and when the profile of the inner shape is milled, an adjustable flexible auxiliary support is added on the outer shape of the part.

Further, in step 11, a process facet perpendicular to the large end face is machined on the part on the same machining reference, and in step 13, the process facet of the two half rings is leveled and then split to re-center the assembly.

In step 17, the tolerance of the step height difference in the large end is reduced to +/-0.01 mm, and when the large end is finish turning, the outer surface of the process step is finish turned together and a certain margin is reserved for subsequent processing.

Furthermore, in the compacting process, in step 21, the small end face is checked by the surface inspection to compact the deformation not more than 0.01mm, if the deformation exceeds 0.01mm, the large end face pad at the corresponding position is adjusted to make up the small end face.

The beneficial effects of the invention are as follows: the two semi-ring blanks which are cut in half in advance are adopted, and then the two semi-ring blanks are connected into the integral ring piece for processing, so that the follow-up turning and milling processing is facilitated, the structure of the fixture is simplified, the larger processing and tooling cost is saved, and the deformation of the cut part of the integral ring forging after the rough processing is avoided; the part is subjected to heat treatment after rough milling, so that the internal stress of the part after rough machining is removed, the deformation generated by stress release in the subsequent process is reduced, and the deformation of the front is removed by repairing the joint surface and the connecting hole again, and then the semi-finishing standard is established again for semi-finishing, so that the subsequent process has a stable and reliable standard and is effectively transferred.

Drawings

FIG. 1 is a schematic view of the overall structure of an aircraft engine aft support ring;

FIG. 2 is a front cross-sectional view of a blank for use in the present invention;

FIG. 3 is a schematic diagram of a repair standard according to the present invention;

FIG. 4 is a schematic view of a mill joint according to the present invention;

FIG. 5 is a schematic view of the assembly structure of one side of the component of the present invention;

FIG. 6 is a schematic diagram of a rough turning small end of the present invention;

FIG. 7 is a schematic diagram of the large end of the rough turning of the present invention;

FIG. 8 is a schematic view of the inside and outside of a rough-milled small end according to the present invention;

FIG. 9 is a schematic diagram of a trim end cap of the present invention;

FIG. 10 is a schematic view of a finish-milled longitudinal mounting edge and end face hole of the present invention;

FIG. 11 is a schematic view of a trimming end cap according to the present invention;

FIG. 12 is a schematic diagram of a semi-finished vehicle large end according to the present invention;

FIG. 13 is a schematic view of a semi-finished vehicle small end according to the present invention;

FIG. 14 is a schematic diagram of the semi-finish milling of the present invention;

FIG. 15 is a schematic diagram of the finish turning large end of the present invention;

FIG. 16 is a schematic view of a finish turning small end according to the present invention;

FIG. 17 is a schematic diagram of a finish-milled small end profile of the present invention;

FIG. 18 is a schematic diagram of a finish-milled large end profile of the present invention;

FIG. 19 is a schematic diagram of a finishing small end calibration of the present invention;

FIG. 20 is a schematic diagram of a finish turning small end standard according to the present invention;

FIG. 21 is a schematic diagram of a finish-milled small end hole of the present invention;

FIG. 22 is a schematic bottom view of FIG. 21;

FIG. 23 is a schematic view of a finish turning large end process station according to the present invention;

FIG. 24 is a schematic diagram of a milling large end slot;

FIG. 25 is a schematic cross-sectional view of a milled large end slot;

fig. 26 is a schematic diagram of a finish-milled joint surface.

Detailed Description

A processing method of an asymmetric rear support ring of an aero-engine, which is used for processing the asymmetric rear support ring of the aero-engine shown in figure 1, wherein in figure 1, a small end mounting edge is arranged; 2-big end installation edge; 3-elliptical holes; 4-big end process installation edge; 5-a big end groove; 6-a large end reinforcing rib; 7-slot plane; 8-square bosses; 9-appearance counter bore; 10-a square hole peripheral boss; 11-square holes; 12-a large end inner side screw hole; 13-an inner small round boss; 14 small end slots. The method specifically comprises the following steps: 1. machining a blank; the annular part is split into two half-ring parts, each half-ring part comprises a large end and a small end which are positioned at two ends of the half-ring part, the diameter of the large end is larger than that of the small end, and the inner part of the large end is in a step shape.

2. Rechecking the blank size; the semi-ring part size is measured, allowance is reserved on each processing surface, the surface quality of the part is checked, forging defects such as slag inclusion, loosening, cracking, overlapping and the like do not occur, a blank structure is shown in fig. 2, and the broken line shape in the section of fig. 2 represents the cross section shape of a semi-finished product machined by the rear support ring.

3. Repairing a standard; and in a free state (different from the fixing together by a connecting piece, the free state is just that the two semi-ring parts are spliced together) the joint surfaces of the two semi-ring parts are jointed to form a circular ring shape, the step surface A of the part is positioned and pressed by a small end, the end surface of the large end is turned flat for positioning, as shown in figure 3, and the thicker part in the figure is the processing position of the step similar to the following figures.

4. Milling a joint surface; positioning by using the end face of the large end, leveling the planes of the joint surfaces on the left side and the right side, centering the center of the half ring, compacting the small end of the part, roughly milling the longitudinal mounting edge 15 formed by extending the joint surface outside the part according to fig. 4, machining the connecting hole 16 and the positioning pin hole on the longitudinal mounting edge 15, and milling the inner circle of the small end for alignment in the next procedure according to the same axis reference.

5. Combining; the two semi-ring parts are fixedly connected through the machined connecting holes by using the connecting piece to form an integral ring part, specifically, the large end of the part is horizontally placed on the working platform downwards, 4 positioning pins 17 are firstly installed, and then the two semi-rings are combined into an integral ring by using 6 connecting bolts 18, as shown in fig. 5.

6. Rough turning two ends and molded surfaces; when the small end is roughly turned, the large end of the combined circular ring part is positioned and clamped by the equal-height iron and four claws, the small end and the outer molded surface of the circular ring part are roughly turned on a numerical control lathe, and part of the allowance is removed, as shown in fig. 6. Then the part is turned over, the small end face is supported on the equal-height iron, the small end excircle is clamped by a four-jaw chuck, the large end and the inner molded surface of the part are roughly turned, part of the allowance is removed, and a large end process step 19 is machined at the large end outer molded surface, as shown by the thickened line part in fig. 7. Considering that the radial deformation trend of the subsequent working procedure of the part is large and the axial deformation is small, the part is uniformly reserved for 6mm in the radial direction and 4mm in the height direction.

7. Rough milling of inner and outer profiles; positioning by using a large end face and an inner hole, pressing the large end process step, rough milling an inner contour and an outer contour, specifically, adding an adjustable flexible auxiliary support consistent with the molded surface on the inner contour to increase the rigidity of the part, and rough milling the outer contour of the part on a five-axis machining center (rough milling a boss, a hole and the like on the contour surface) according to FIG. 8; then removing the inner support, adding an adjustable flexible auxiliary support on the shape of the part, and rough milling the inner contour; the rough milling outline retains the same machining allowance (6 mm) as the rough turning procedure.

8. Stress-relieving heat treatment; in order to remove internal stress of the part after rough machining and reduce deformation generated by stress release in the subsequent working procedure, carrying out stress-removing heat treatment on the part in an air furnace after rough milling is finished; in order to prevent the excessive deformation of the parts in the heat treatment process, the parts are fed into a furnace for heat treatment in a combined state.

9. Splitting; and (5) removing the part connecting bolts and the positioning pins to enable the ring parts to be split to form two semi-ring parts.

10. Repairing a large end reference; and in a free state, the joint surfaces of the two semi-ring parts are jointed to form a ring shape, the small end is positioned and pressed on a machine tool workbench, and the end surface of the large end and the positioning step are turned, as shown in fig. 9.

11. Finish milling the joint surface; after the upper surface of the large-end process step is positioned and pressed by the large-end face and the positioning step, the five-axis machining center is finish-milled with the longitudinal installation edge, the connecting hole on the longitudinal installation edge and the positioning pin hole, as shown in fig. 10; in order to facilitate the alignment of the centers of the two half rings in the turning process, the alignment process facets (for example, the facets can be milled on the same reference in the direction of 90 ° of the large end, that is, in the direction parallel to the direction of the cutting joint surface of the support ring) are cut on the part.

12. Combining; the large end of the part is horizontally placed on the working platform downwards, 4 positioning pins are firstly installed, and then 8 connecting bolts are used for combining the two semi-rings into an integral ring structure.

13. Repairing a small end reference; the stress release (stress removal by heat treatment) of the preamble can generate larger deformation, the center of the part is offset after finish milling the joint surface, the deformation of the two semi-rings is inconsistent, the allowance required to be removed for milling the joint surface is different, a new part center is required to be established by a process facet processed on the large end mounting edge by a milling process after combination, and a reliable reference is provided for the subsequent process. Specifically, the positioning is performed by using the large end face, the upper surface of the large end process step is pressed, the center of the assembly is redetermined, and then the small end face and the inner circle of the small end spigot are finely turned by using the center as a reference, so that the flatness and the inner circle roundness of the end face in a free state are ensured, as shown in fig. 11. The method of re-centering the assembly may utilize the process facets described above to split the two half-ring large end process facets after leveling.

14. Semi-finish turning the profile of the large end and the small end; the main purpose of the semi-finish turning process is to eliminate the deformation of the parts after assembly and to further remove blank margin. The small end face and the inner cylindrical surface 20 of the spigot are used for positioning, the large end profile is half finish turned, and the uniform allowance of the profile is 2mm, as shown by the thickened line in fig. 12. And then turning over the part, positioning by using the large end face and the large end inner round spigot 21, compacting from the upper surface of the large end process step, semi-finish turning the small end molded surface (the molded surface is uniform and the allowance is 2 mm), and strictly controlling the whole height and the size of the round inner hole of the positioning spigot, as shown in a thickened line part in fig. 13.

15. Semi-finish milling of inner and outer profiles; positioning by using a large end face and an inner hole, pressing the upper surface of a large end process step, and semi-finish milling the inner and outer profiles; specifically, an adjustable flexible auxiliary device is adopted in the inner type to support the inner type surface so as to increase the rigidity of the part, reduce the processing vibration cutter, improve the surface quality and reduce the processing deformation, and the profile is uniformly reserved by 2mm to carry out profile semi-finish milling; and after the appearance is finished, removing the inner support, supporting the outer molded surface by adopting an adjustable flexible auxiliary device on the milled outer molded surface, and carrying out semi-finish milling on the inner contour by uniformly reserving 2mm of the molded surface, wherein the semi-finish milling is shown in fig. 14.

16. Stabilizing treatment; because of the larger size of the parts, the parts are selected to be stabilized in an air furnace, and the internal stress of the parts is removed by heat treatment at a lower temperature in a combined state, and the small change of the size of the combined parts is kept.

17. Finish turning the large end; positioning by using the small end face and the inner cylindrical surface of the spigot, finely turning the large end profile according to fig. 15, and keeping the process boss structure of the large end for part positioning consideration, wherein the end face and the inner allowance are 1mm; in order to ensure reliable positioning during milling, the height difference of the inner steps is reduced to +/-0.01 mm, so that the milling fixture is convenient to oversubscribe and clamp. In order to facilitate alignment of the parts after clamping, the outer surface B of the small cylinder at the lower end of the process step is finish-turned together, and the allowance is 1mm until the process of finishing the large end is finished.

18. Finely turning the small end; positioning by using the inner cylindrical surface of the large end face and the spigot, finely turning the small end face and the inner and outer circles according to FIG. 16, and strictly controlling the whole height of the part and the inner hole size of the positioning circle; preferably, the small end excircle is processed to be 2mm in thickness beyond the longitudinal mounting edge.

19. Finish milling of the small end profile; positioning by using a large end face and a large end inner hole, compacting the upper surface of a process step, and finish milling the outline near the small end; specifically, in order to increase the rigidity of the part, reduce the vibration cutter during milling, improve the quality of the processed surface, and increase the adjustable flexible auxiliary support on the inner conical surface, the square boss 8 and the square hole peripheral boss 10 are finely milled firstly, then the outer conical surface is finely milled to the final size and is smoothly connected with the round corners of the boss, so that the efficiency of finely milling the conical surface can be greatly improved. Because the longitudinal mounting edges are only used for process connection, notches on two sides are cut off and formed in the final working procedure, the longitudinal mounting edges do not need to be finish-milled any more when the profile is finish-milled, and the width of the profile conical surface exceeding the final notch plane 7 is preferably about 5mm when the profile conical surface is finish-milled; finish milling the elliptical hole 3 and the square hole 11 to final sizes, wherein asymmetric tolerance is required for the elliptical hole, and programming is required according to a middle difference value during programming; and finally, the thickness of the upper installation edge is ensured on the lower side surface of the small end installation edge 1 by finish milling, and the height difference of the upper installation edge and the lower installation edge is ensured on the upper surface of the large end installation edge 2 by finish milling. After the exterior is machined, the inner auxiliary support is removed, the flexible adjustable auxiliary support is uniformly arranged on the exterior conical surface, a circle of round small boss is formed on the upper part of the inner conical surface of the part, and then the upper half part of the inner conical surface is finely milled. Specifically, as shown in fig. 17, the step of placing the lower part of the conical surface and the round boss at the lower side thereof into the finish milling large end is performed.

20. Finish milling of the large end profile; turning over the part with the finish-milled small end, installing a clamp, positioning the end face and the inner hole of the small end, compressing along the upper side of the installation edge of the small end, and finish-milling the outline near the large end; specifically, an inner small round boss 13 is finely milled on the upper part of the inner conical surface, then an inner square boss opposite to the square boss 8 and the peripheral boss 10 of the square hole are finely milled, and then the upper half part of the inner conical surface is finely milled to ensure the final wall thickness requirement and is connected with the boss root processed in advance in a flat manner, as shown in fig. 18. The internal working procedure is divided into two working procedures, so that the direct machining of the machine tool spindle can be realized, programming can be simplified (the elbow machining is avoided), the machining efficiency can be improved, the machined lines are more regular and consistent, and the surface quality is better.

21. Finishing a small end reference; and positioning the large end face and the large end inner hole, pressing the upper surface of the technological step, and processing and removing allowance on the small end face and the inner and outer circles to obtain the final size. Specifically, in the compacting process, the compaction deformation is checked by striking a table, and is not more than 0.01mm (small end deformation), if the deformation exceeds 0.01mm, a proper adjusting gasket is required to be padded at the corresponding large end face part, so that the influence of the rebound of the part on the flatness and roundness of the machined small end after the part turning is finished and the clamp is released is avoided. During machining, a margin of 0.15mm is reserved on the inner circle and the end face, the final dimension is obtained by finishing and removing the margin by the last cutter, so that good surface quality, flatness and roundness are ensured, and a machining schematic diagram is shown in fig. 19.

22. Finishing a large end reference; the inner cylindrical surface of the spigot and the end face of the small end are positioned, the back of the installation edge of the small end is utilized for compaction, the end face of the large end is finely turned to ensure the total height to the final size and the parallelism requirement, then the inner molded surface is finely turned to the final size so as to process the subsequent hole, and the processing schematic diagram is shown in figure 20. The process step outside margin remains to enhance positioning stability.

23. Finish milling of small end holes; positioning the finished large end face and inner hole, pressing the large end process step, carrying out internal auxiliary support on the part, adjusting an adjusting bolt according to the molded surface position of the part so as to realize reliable support, drilling and reaming a small hole on the small end mounting edge 1 and milling a threaded hole on the upper side of the large end mounting edge 2 after the jump of the small end inner circle is not more than 0.03mm, then finish milling an external counter bore 9, a through hole on the square hole peripheral boss 10 and a large hole on the square boss 8, finally finish milling a notch plane 7 and processing a connecting hole 16 on the connecting plane to a required size, wherein the width of the finish milling connecting plane is consistent with the processing width of the conical surface during finish milling, and the processing schematic diagrams are shown in fig. 21 and 22.

24. Turning a process table; the inner cylindrical surface of the spigot and the end face of the small end are used for positioning, the surface of the installation edge of the small end is used for pressing, the profile of the installation edge 4 and the profile of the installation edge of the large end are finely turned to the final size according to the figure 23, the thickness of the thin edge wall of the process table and the height of the installation edge are mainly ensured, and the parts are transferred to the next working procedure along with the clamp after turning.

25. Finish milling of the large end groove and the hole; the fixture with the parts is assembled on a machine tool, after the parts are aligned, the inner side screw holes 12 of the large ends are milled, then the asymmetric large end grooves near the longitudinal joint surfaces are milled, and finally the positioning stud holes on the bottom surfaces of the large end grooves are milled, wherein the processing schematic diagrams are shown in fig. 24 and 25.

26. Splitting; and (3) removing the positioning pins and the connecting bolts on the longitudinal mounting edge, and splitting the whole ring part into two parts so as to facilitate the subsequent processing of notch areas respectively.

27. Finish milling the joint surface; the small end of the semi-ring part is upward, the small end of the semi-ring part is positioned by the large end face and the inner hole of the large end thin-wall straight edge, the positioning stability can be enhanced by adopting an over-positioning mode on the lower surface of the large end reinforcing rib 6 (positioning supporting blocks are additionally arranged on the notch at the two ends), the large end mounting edge (in particular, the inclined surface of the semi-ring part) and the upper surface of the large end reinforcing rib 6 are tightly pressed, the longitudinal mounting edge is firstly milled, then the notch is finely milled to the required shape and angle, and the processing schematic diagram is shown in fig. 26.

28. Clamping; the bench worker removes surface defects such as milling burrs, surface scratches, indentations and the like of parts; and then marking a vibration pen in a designated area to be used as a traceability mark of the part.

29. Performing fluorescence penetration inspection; checking whether all the processing surfaces of the part have defects such as cracks and the like; if the defect exists, returning to the previous working procedure for reworking, and performing fluorescence penetration inspection again.

According to the rear support ring processing method, two semi-ring blanks which are split and cut in half in advance are adopted, the circumferential distribution positions of the two asymmetric upper/lower rear support rings are reasonably adjusted and designed, and two longitudinal process mounting edges are added to connect the two semi-ring blanks into an integral ring piece for processing, so that subsequent turning and milling processing is facilitated, the structure of a fixture is simplified, larger processing and tooling cost are saved, and deformation of the cut parts of the integral ring forging after rough processing is avoided; the method reserves a process step when the large end is roughly turned, enhances the rigidity of the large end, and is convenient for clamping and positioning parts during subsequent rough milling, semi-finish turning, semi-finish milling, finish milling and finish turning, so that the parts are more convenient and efficient to process; and carrying out heat treatment on the part after rough milling to enable the rough machined semi-finished product part to be fully deformed, and carrying out recombination machining after removing the deformation of the preamble to establish a semi-finish machining reference by repairing the joint surface and the connecting hole again, so that the subsequent working procedure has a stable and reliable reference and is effectively transferred. Meanwhile, the allowance distribution of semi-finishing and finishing is reasonably arranged, the processing deformation in the finishing process is effectively reduced, the final processing precision of the part is greatly improved, the part is ensured to meet the drawing requirements, and the assembly requirements of the assembly are met.

The present invention is not limited to the above-mentioned embodiments, and any changes or substitutions that can be easily understood by those skilled in the art within the scope of the present invention are intended to be included in the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A processing method of an asymmetric rear support ring of an aero-engine comprises the following steps: the method is characterized in that the annular part is split into two semi-annular parts in half during the blank processing, and then the two semi-annular parts are subjected to subsequent processing; before rough machining, connecting the two semi-ring parts into an integral annular part for machining, after rough milling, carrying out stress relief heat treatment on the integral annular part formed by connecting the two semi-ring parts, then splitting and trimming the integral annular part, reconnecting the integral annular part into an integral annular part, establishing a semi-finishing reference, and carrying out machining according to the semi-finishing reference during semi-finishing.

2. The method for machining an asymmetric rear support ring of an aircraft engine according to claim 1, wherein the method comprises the following steps: the method specifically comprises the following steps: 1. machining a blank; the annular part is split into two semi-annular parts, each semi-annular part comprises a large end and a small end which are positioned at two ends of the semi-annular part, the diameter of the large end is larger than that of the small end, and the inner part of the large end is in a step shape;

25. finish milling of the large end groove and the hole;

28. clamping; removing surface defects;

3. The method for machining an asymmetric rear support ring of an aircraft engine according to claim 2, wherein the method comprises the following steps: in step 6, the part is uniformly spaced in radial direction Amm and in height direction Bmm, A being greater than B.

4. The method for machining an asymmetric rear support ring of an aircraft engine according to claim 2, wherein the method comprises the following steps: in the steps 7, 15 and 19, when the profile of the outer shape is milled, an adjustable flexible auxiliary support which is consistent with the profile is added on the inner shape to increase the rigidity of the part, and when the profile of the inner shape is milled, an adjustable flexible auxiliary support is added on the outer shape of the part.

5. The method for machining an asymmetric rear support ring of an aircraft engine according to claim 2, wherein the method comprises the following steps: in step 11, a process facet perpendicular to the large end face is machined on the part on the same machining reference, and in step 13, the process facet of the two half rings is leveled and then split to re-center the assembly.

6. The method for machining an asymmetric rear support ring of an aircraft engine according to claim 2, wherein the method comprises the following steps: in step 17, the tolerance of the height difference of the inner step of the large end is reduced to +/-0.01 mm, and when the large end is finely turned, the outer surface of the process step is finely turned together and a certain margin is reserved for subsequent processing.

7. The method for machining an asymmetric rear support ring of an aircraft engine according to claim 2, wherein the method comprises the following steps: and 21, in the compacting process, performing surface marking on the small end face to check that compacting deformation is not more than 0.01mm, and if the deformation exceeds 0.01mm, filling a large end face at a corresponding position with an adjusting gasket to level the small end face.