A multi-piece machining device and method for an abnormal-shaped ultra-thin wall casing of an aero-engine vector nozzle

Abstract

A processing method for machining an ultra-thin-wall casing of a special-shaped tail nozzle of an aircraft engine comprises two oblique cylindrical workpieces, wherein the oblique sides of the two workpieces are assembled together to form a complete cylindrical shape; the inner and outer shapes of the cylindrical parts are roughly turned, the cylindrical inner cavity is roughly milled, and after vacuum tempering, the outer circle reference and upper and lower end faces of the cylindrical part are turned, and the inner cavity is finely milled; the tooling used is a cylindrical barrel with an outer diameter equal to the inner diameter of the cylindrical part, and the cylindrical barrel is composed of three to six parallel vertical arc-shaped plates; the tooling is assembled with the cylindrical part and tightly combined with the workpiece as a lining to form a whole; after the cylindrical part is fixed vertically on a table of a machining center, the outer shape of the cylindrical part is machined by programming in the machining center to machine an integrated thin cylindrical structure including a 6mm thick reinforcing rib and a 1mm thick barrel wall; after machining, the cylindrical barrel is cut by arc programming to form two obliquely divided cylindrical workpieces.

Description

Technical Field

[0001] The invention relates to a processing tooling device and method for combined processing of multiple pieces of special-shaped ultra-thin-wall casings of an aerospace engine. Background Art

[0002] Casings are an essential component of modern engines. With the development of modern aero-engines, large-diameter, special-shaped, thin-walled casings (including any cylindrical thin-walled parts, especially those with complex outer shapes requiring five-axis machining centers) are becoming increasingly difficult to process. Due to the increasing number of ultra-thin-walled casings, machining of these parts is becoming increasingly difficult. The most common problems encountered after machining these parts include uneven wall thickness, dimensional tolerances, tooling that cannot be reused, and the impact of part tolerances on part quality control and clamping surface fit. When faced with the machining of ultra-thin-walled casings, some of the previously used effective methods and fixed fixtures cannot simultaneously address these issues.

[0003] A thrust-vectoring aircraft engine is one in which the nozzle can be deflected in different directions to generate thrust in different directions. Simply put, a thrust-vectoring aircraft engine can rotate in different directions to generate acceleration in different directions. In aircraft without thrust vectoring, the engine's jet is aligned with the aircraft's axis, and the generated thrust is also directed forward along the axis. In this case, the engine's thrust is used solely to overcome drag and provide acceleration. Aircraft using thrust vectoring utilize the engine's thrust by deflecting the nozzle to generate excess control torque for attitude control. Its key feature is that the control torque is closely tied to the engine and is not affected by the aircraft's attitude. Therefore, when maneuvering at low speeds and high angles of attack, when control surfaces are nearly ineffective, the additional control torque provided by thrust vectoring can be used to control the aircraft. Aircraft using thrust vectoring not only significantly enhance maneuverability but also possess unprecedented short-field takeoff and landing capabilities. This is because the hyperloop lift and the lift component of the thrust generated by a thrust-vectoring aircraft help reduce liftoff and touchdown speeds, shortening the aircraft's roll distance. In addition, because the thrust vectoring nozzle can easily achieve thrust reversal, the braking force of the aircraft after landing is also greatly improved, so the landing roll distance is further shortened. If the engine nozzle can not only deflect up and down, but also deflect left and right, then the thrust can not only provide the aircraft's pitch moment, but also provide yaw moment. This is a full-vector aircraft. The use of thrust vectoring technology improves the control efficiency of the aircraft. The nozzle that can deflect in different directions, namely the tail nozzle (i.e., the thrust vectoring nozzle, is an extremely critical component. It not only has to withstand extremely high-temperature airflow and force, but also has high precision requirements and light weight; it has thin walls and is particularly complex in shape. It is almost impossible to install multiple components, and it needs to be integrated during manufacturing;

[0004] likeFigure 1 The workpiece shown has a reinforcing rib on the outer wall of the ultra-thin-walled casing (an integrated component prepared on the tail nozzle casing); the thickness of the rib is 6±0.1MM, the width is 5MM, and the thickness of the rest of the place is 1.1±0.1MM. The R angle between the rib and the outer wall is R3, the inner cavity contour requirement is 0.1MM, and the workpiece diameter is about 1 meter. The thickness of most ultra-thin-walled casings is 1.1±0.1MM. This thickness cannot solve the problem of accuracy during five-axis machining, and it is certainly impossible to meet the stringent requirement of 10 microns in machining accuracy. For example, CN 2014107292053 discloses a tool for vertical lathe machining of annular conical thin-walled parts, including: a tool base plate, which is a disk with a through hole in the center, and one end of a core shaft passes through the center through hole and is fixed to the tool base plate; a plurality of bulging sliders, one end of the bulging slider serves as a clamping surface, and its end face contour matches the curved surface of the inner wall of the workpiece to be machined, and the other end serves as a driving end, and its end face is an inclined surface; a conical block, which is sleeved on the core shaft and whose conical surface matches the conical space. It can be driven to interact with the conical space, thereby driving each bulging slider to slide radially on the guide rail so that the clamping surface of each bulging slider abuts against the inner wall of the workpiece, thereby clamping it for machining.

[0005] CN201910953825.8 A processing method for an axisymmetric thin-walled suspended structure, the axisymmetric thin-walled suspended structure includes an axis and a plane or groove feature based on axisymmetry, including the steps of: using a three-jaw chuck to clamp the parts of the axisymmetric thin-walled suspended structure, rough-turning the end face and outer circle of the axle, leaving an allowance; wire-cutting a groove of a fixed shape and removing excess machining allowance on the plane, leaving a process allowance of 1 to 3 mm; making two center holes or chamfered holes; turning the end face, and drilling center holes or chamfered holes in the groove and the end face of the axis of the axisymmetric thin-walled suspended structure; the double center holes or chamfered holes are on the same axis; clamping the parts of the axisymmetric thin-walled suspended structure to a turning tool, clamping the cylindrical surface of the tooling positioning column with a three-jaw chuck, and the center hole on the side of the tooling plane supports the center hole at the bottom of the part groove, and the other end uses the center hole of the lathe tailstock to support the center hole or chamfered hole, and fine-machining the various sizes of the outer circle of the part; grinding the center hole; and fine-milling the two symmetrical planes of the cantilever.

[0006] The shape of the entire workpiece of the ultra-thin wall casing of the special-shaped tail nozzle of the aircraft engine is like an elliptical surface with two long axes at a 90-degree angle (such as Figure 2 ), the outer surface shape is more complicated, and it is impossible to pass through the fixed tooling that matches the inner cavity from either end, so it is impossible to form effective support in the inner cavity. Moreover, due to the material of the parts, it cannot be processed by pouring tin-bismuth alloy, pouring wax, etc. Figure 1-2In the structural diagram shown, the key issues to be addressed are ensuring clamping safety and solving the impact of part tolerances on part quality (especially accuracy requirements, eliminating the impact of deformation during processing on accuracy). The present invention is a more general processing method and device proposed to address this new problem. At the same time, it also realizes the processing of multiple combined cylindrical parts, improves processing efficiency, and simplifies the processing process. Summary of the Invention

[0007] The purpose of the present invention is to propose a large-diameter cylindrical special-shaped thin-walled casing (including any cylindrical thin-walled parts, especially thin-walled parts, the outer wall of the thin-walled parts has a complex shape and requires a five-axis machining center to be processed), to solve the deformation-free processing and cutting of the finished aircraft engine special-shaped (oblique-cut cylindrical) tail nozzle ultra-thin-walled casing cylindrical parts, especially to ensure high processing accuracy and no deformation of the more complex outer surface shape. The present invention includes a processing tooling device and method for the combined processing of multiple pieces of aircraft engine special-shaped ultra-thin-walled casings.

[0008] The technical solution of the present invention is a tooling device and method for the combined processing of multiple pieces of special-shaped ultra-thin-walled casings of aircraft engines. The tooling device comprises two oblique cylindrical workpieces, the oblique edges of which are assembled together to form a complete cylindrical shape. An extension section is added to the middle of the cylindrical workpiece, a transition section at the upper end and an angular control edge at the lower end are added, and an offset positioning pin hole is machined on the angular control edge for standby use.

[0009] According to the rough turning of the inner and outer shapes of the cylindrical parts, rough milling of the cylindrical cavity, vacuum tempering, turning of the outer circle reference and upper and lower end faces of the cylindrical parts, and fine milling of the inner cavity;

[0010] The process flow of installing the tooling and fine milling the tooling outer contour and the upper and lower mounting edges of the tooling; determining the eccentric angular hole on the end face when rough turning the inner and outer shapes of the cylindrical parts; the thickness of the part still retains the thickness of the cylinder wall when rough turning the inner and outer shapes of the cylindrical parts and fine milling the inner cavity;

[0011] The tooling is a cylindrical tube with an outer diameter equal to the inner diameter of the cylindrical part. The cylindrical tube is composed of three to six parallel vertical arc-shaped plates. A disc is embedded in the upper and lower ends of the cylindrical tube. Holes are evenly arranged in pairs in the center or on the edges of the upper and lower discs. A fixed pull rod is provided between the holes in the center of the upper and lower discs or in pairs. The fixed pull rod is fixed to the upper and lower disc surfaces with screws and nuts. The upper and lower edges of the cylindrical tube are provided with upward or downward withdrawal angles at the contact points with the upper and lower discs. The angle between the withdrawal angle and the vertical line is 2-15 degrees. The lower end of each arc-shaped plate can be fixed to a flange-shaped bottom plate in a radially adjustable manner. The upper and lower discs serve as an upper pressure plate and a lower top plate.

[0012] After being assembled with the cylindrical part, the tooling is tightly combined with the workpiece as the inner lining to form a whole. After the cylindrical part is fixed vertically on the table of the machining center, the outer shape of the cylindrical part is processed by programming on the five-axis machining center to produce an integrated thin cylindrical structure including 6mm thick reinforcement ribs and 1mm thick barrel wall. After processing, the cylindrical barrel is cut by arc programming to form two cylindrical workpieces divided by an oblique line.

[0013] The tooling is a cylindrical tube with an outer diameter equal to the inner diameter of the cylindrical part, comprising three to six parallel vertical arc-shaped plates (the cylindrical tube is cut into 3-6 pieces) assembled into a cylindrical tube; a disc is embedded in the upper and lower ends of the cylindrical tube, and holes are evenly arranged in pairs in the center or at the edges of the upper and lower discs. A fixed pull rod is arranged between the holes in the center of the upper and lower discs or in pairs, and the fixed pull rod is fixed to the upper and lower disc surfaces with screws and nuts; the upper and lower edges of the cylindrical tube are provided with an upward or downward withdrawal angle at the contact points with the upper and lower discs, and the angle between the withdrawal angle and the vertical line is 2-15 degrees; the lower end of each arc-shaped plate can be fixed to a flange-shaped bottom plate in a radially adjustable manner, and the upper and lower discs serve as an upper pressure plate and a lower top plate;

[0014] After the parts are assembled, the tooling is tightly combined with the workpiece lining to form a whole. After the workpiece is fixed vertically on the table of the machining center, the outer shape of the workpiece is processed by programming on the five-axis machining center, especially the integrated thin tube structure including 6mm thick reinforcement ribs and 1mm thick barrel wall. After the processing is completed, the cylindrical tube is cut by arc programming to form two oblique-cut cylindrical workpieces.

[0015] The vertical arc-shaped plates of the tooling cylindrical barrel are selected as the first group and the second group, which are a total of four movable brackets, namely arc-shaped plates, which are assembled alternately. The central angle of the two movable brackets in the first group is 45°±15°, and the central angle of the two movable brackets in the second group is 135°±15°. The four alternating movable brackets are movable brackets No. 1, No. 2, No. 3 and No. 4: the fixed bracket is fixed to the flange-shaped base plate by two pins on one side: insert the two locating pins 19 into the pin holes of the base plate 21, put the locating pin holes on the No. 1 fixed bracket 2 into the locating pins 19 and fix the No. 1 fixed bracket 2 to the base plate 21 with six screws 20 to complete the installation of the No. 1 fixed bracket 2; the arc of the movable bracket The lower end of the arc-shaped plate is radially adjusted by a guide bar and is fixed to a flange-shaped base plate by a pressure plate: a telescopic screw 14 is screwed into the threaded hole of the T-slot end of the No. 2 movable bracket 10 (i.e., the lower end of the arc-shaped plate) and screwed in an appropriate distance, and two guide keys 12 are inserted into the T-slot below the movable bracket. This assembly is placed on the base plate 21 so that the guide keys 12 are snapped into the corresponding key slots on the base plate 21. The position of the No. 2 movable bracket 10 is adjusted, and the guide keys 12 are fixed to the base plate 21 with two screws 13, thereby completing the installation of the No. 2 movable bracket 10. Similarly, the installation of the No. 3 movable bracket 11 and the No. 4 movable bracket 1 is completed.

[0016] Adjust the No. 2 to No. 4 movable brackets to the appropriate position by using the telescopic screw 14, and then screw the three top plate screws 9 into the lower top plate 4, and place the small end of the conical surface of the lower top plate 4 upward in the middle of the bottom plate 21, so that its upward surface is basically flush with or slightly lower than the upper surface of the bottom plate 21, screw one end of the pull rod 7 into the central threaded hole of the lower top plate 4, and lock it with a nut 5 to prevent it from loosening during use; then adjust the No. 2 to No. 4 movable brackets to the appropriate position (such as Figure 7 The No. 2 and No. 4 movable brackets are offset more toward the center of the circle, while the No. 3 movable bracket is offset less toward the center of the circle. At this time, part of the No. 2 and No. 4 movable brackets are stuck in the No. 3 movable bracket). Place the workpiece with the angular control side (similar to the flange end) facing down into the tooling (four parallel vertical arc-shaped plates inside the part). Pay attention to the angular direction of the workpiece, place the workpiece to the bottom, and insert the locating pins into the eccentric angular holes on the angular control side and the eccentric locating pin slots on the No. 1 fixed bracket in sequence (such as Figure 7 )Inside.

[0017] The third movable bracket is pulled away from the center of the circle to a suitable position (pull it away from the center of the circle to a suitable position 0) by the telescopic screw 14, and the positioning pin is inserted into the other eccentric angular hole of the angular control side (such as Figure 3 ) and eccentric positioning pin slots (such as Figure 7) inside. Then use the telescopic screw 14 to pull the No. 2 and No. 4 movable brackets away from the center of the circle to the appropriate position (pull them away from the center of the circle to the appropriate position 0), and fix the height limit block 18 on the bottom plate 21 with the screw 3 17. Pay attention to the gap between the height limit boss of the height limit block 18 and the workpiece, and ensure that the workpiece has a certain amount of space for movement (such as Figure 9 ). Rotate the telescopic screw 14 so that its round end is in close contact with the movable bracket where it is located.

[0018] Use an Allen wrench to rotate the top plate screw 9 downwards and lift the lower top plate (lower disc) 4. When the workpiece is lifted up, the cam 7 is tightened and the workpiece is tightened, so that the inner wall surface of the workpiece fits the outer wall surface of each movable bracket. Use a feeler gauge to check the gap between the fitting surfaces. When the requirements are met, the cam 7 can be tightened again.

[0019] The tooling of the present invention is a special tooling, which is designed for the combined processing of multiple pieces of special-shaped ultra-thin-walled casings of aircraft engines. The tooling is a cylindrical barrel with an outer diameter equal to the inner diameter of the cylindrical part, and includes three to six parallel vertical arc-shaped plates (the cylindrical barrel is cut into 3-6 pieces) assembled into a cylindrical barrel; a disc is embedded in the upper and lower ends of the cylindrical barrel, and holes are evenly arranged in pairs in the center or the edges of the upper and lower discs. A fixed pull rod is provided between the holes in the center of the upper and lower discs or the paired holes, and the fixed pull rod is fixed to the upper and lower disc surfaces with screws and nuts; the upper and lower edges of the cylindrical barrel are provided with upward or downward setback angles (trumpet-shaped angles) at the contact points with the upper and lower discs, and the angle between the setback angle and the vertical line is 2-15 degrees; the lower end of each arc-shaped plate can be fixed on a flange-shaped base plate in a radially adjustable manner.

[0020] In the embodiment, the upper and lower discs are an upper pressing plate and a lower top plate.

[0021] Beneficial effect: The core requirement of the tooling designed by the present invention is that when four pieces (3-6 pieces are acceptable, more pieces are also acceptable, and four pieces are taken in the embodiment of the present invention, which is a good way) of the bracket are expanded, the required outline size (of a cylindrical cylinder or an expanded and deformed cylindrical cylinder) can be achieved, and it is suitable for cylindrical cylinders or the expansion of cylindrical cylinders (cylindrical cylinder workpieces may have concave and convex shapes). The ultra-thin-wall casing of the special-shaped tail nozzle of the aircraft engine used for processing the finished product of the present invention is a cylindrical part, and the reinforcing ribs on the outer surface of the cylindrical part are processed and cut without deformation, especially to ensure high processing accuracy and no deformation of the more complex outer surface shape. The processing tooling device and method for the combined processing of multiple pieces of the special-shaped ultra-thin-wall casing of the aircraft engine proposed by the present invention enable high-precision workpiece processing to be completed, especially to achieve an accuracy of 10 microns. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the ultra-thin-wall casing of an aircraft engine's special-shaped tail nozzle;

[0023] Figure 2 for Figure 1 A schematic diagram of the outer contour of an ultra-thin-walled casing, which is the processing object of the present invention;

[0024] Figure 3 Schematic diagram of the processing of combining multiple ultra-thin-walled casings into a barrel.

[0025] Figure 4 Shown is a 3D diagram of the combined processing of multiple parts of an aircraft engine's special-shaped ultra-thin-walled casing.

[0026] Figure 5 The figure shows an assembly diagram of the present invention, in which the round end of the telescopic screw 14 corresponding to the telescopic stopper 16 is just stuck in the groove of the telescopic stopper 16 during assembly;

[0027] Figure 6 Shown is an assembly diagram of the present invention, a schematic diagram of placing the workpiece on the bottom;

[0028] Figure 7 The figure shows an assembly diagram of the present invention, which is a schematic diagram of inserting a positioning pin into the eccentric angular hole of the angular control edge and the eccentric positioning pin slot of the No. 1 fixing bracket 2 in sequence.

[0029] Figure 8 The figure shows the assembly diagram of the present invention, in which the round head end is just stuck in the groove of the telescopic stopper 16;

[0030] Figure 9 The figure shows an assembly diagram of the present invention, in which the height limit block 18 is fixed to the bottom plate 21 by screws 17 to ensure that the workpiece has a certain movable space.

[0031] Figure 10 This is the clamping diagram of the workpiece.

[0032] Figure 11 The schematic diagram of the structure of the inner cavity of the entire workpiece is shown as follows: four brackets, namely, the first fixed bracket 2, the second movable bracket 10, the third movable bracket 11 and the fourth movable bracket 1. DETAILED DESCRIPTION

[0033] 1. Arrangement of process route

[0034] In view of the problems of the above-mentioned parts (including similar parts), such solutions are proposed.

[0035] First, because the part is a semi-beveled cylindrical shape, it wastes materials and the processing stability is not good, which is not conducive to improving efficiency. Therefore, the following method is used: Figure 3 The method of merging two pieces for processing. It includes two oblique cylindrical workpieces, and the oblique sides of the two workpieces are assembled into a complete cylinder; in the cylindrical tube, the workpiece is added with an extension section 1, a transition section 3 at the upper end and an angular control edge (which can be a flange edge) 5 at the lower end, and two offset positioning pin holes are processed on the angular control edge 5 for standby; according to the rough turning of the inner and outer shapes of the cylindrical parts (leaving a margin to control deformation on the outside and a rough machining margin on the inside), the cylindrical inner cavity is rough milled (the margin is greater than the deformation amount of heat treatment), and after vacuum tempering, the outer circle reference and upper and lower end faces of the cylindrical parts are turned (pay attention to the control of the outer circle margin), and the inner cavity is finely milled (to ensure the accuracy of the inner cavity contour); the two workpieces form a complete cylindrical shape, which increases the rigidity of the parts, is conducive to the control of the inner cavity contour, is easy to process, and is also convenient for the design and manufacture of tooling fixtures; the process of installing the tooling and fine milling the outer contour of the tooling and milling the upper and lower mounting edges of the tooling is used to complete the processing of the parts, thereby meeting the design requirements of the drawings and meeting the needs of batch production; when rough turning the inner and outer shapes of the cylindrical parts, the end face eccentric angular hole is determined; when rough turning the inner and outer shapes of the cylindrical parts and fine milling the inner cavity, the thickness of the parts still retains the thickness of the cylinder wall (there is a margin for processing the reinforcement ribs of the outer wall, etc.), thereby ensuring the wall processing accuracy;

[0036] The method is to place two workpieces 22 and 24 obliquely facing each other to form a workpiece cylinder, add an extension section 27 to the workpiece cylinder, add a transition section 23 at the upper end and an angular control edge 25 (similar to a flange) at the lower end, and machine two offset positioning pin holes 26 on the angular control edge 25 (flange edge) for standby use. This allows the two workpieces (22, 24) to form a complete cylindrical shape, increases the rigidity of the parts (workpieces), facilitates inner cavity contour control, facilitates processing, and also facilitates the design and manufacture of fixtures.

[0037] Figure 3As shown, two workpieces 22 and 24 are combined to form a cylinder, angular control edge 25, locating pin hole 26, extension section 27, and transition section 23. Tooling component list: 1. Movable bracket No. 4, 2. Fixed bracket No. 1, 3. Upper pressure plate, 4. Lower top plate, 5. Nut 1, 6. Nut 2, 7. Pull rod, 8. Washer, 9. Top plate screw, 10. Movable bracket No. 2, 11. Movable bracket No. 3, 12. Guide key, 13. Screw 1, 14. Telescopic screw, 15. Screw 2, 16. Telescopic stop, 17. Screw 3, 18. Height limit block, 19. Locating pin, 20. Screw 4, 21. Base plate (which secures the movable brackets to form the cylinder).

[0038] Secondly, according to the process flow of rough turning the inner and outer shapes of the parts (leaving an allowance on the outside to control deformation and leaving an allowance for rough machining on the inside), rough milling the inner cavity (the allowance is greater than the deformation due to heat treatment), vacuum tempering, turning the outer circle datum and the upper and lower end faces (pay attention to the control of the outer circle allowance), drilling eccentric angular holes on the end faces and fine milling the inner cavity (ensuring the requirements of the inner cavity contour), and then finishing the outer contour and milling the upper and lower mounting edges on the tooling to complete the processing of the parts, so as to meet the design requirements of the drawings and meet the needs of mass production.

[0039] 2. According to the requirements of the processing flow, design a simple and practical fixture that can ensure quality requirements, effectively eliminate the impact of part deformation on wall thickness, and is suitable for batch processing.

[0040] In response to the requirements of this type of parts, a processing device for the combined processing of multiple pieces of aircraft engine special-shaped ultra-thin wall casings was designed, such as Figure 4 . Figure 4 Shown is a 3D diagram of the combined processing of multiple parts of an aircraft engine's special-shaped ultra-thin-wall casing.

[0041] Figure 4 As shown: Detailed list of tooling components: 1. Movable bracket No. 4, 2. Fixed bracket No. 1, 3. Upper pressure plate, 4. Lower top plate, 5. Nut one, 6. Nut two, 7. Pull rod, 8. Washer, 9. Top plate screw, 10. Movable bracket No. 2, 11. Movable bracket No. 3, 12. Guide key, 13. Screw one, 14. Telescopic screw, 15. Screw two, 16. Telescopic stopper, 17. Screw three, 18. Height limit block, 19. Positioning pin, 20. Screw four, 21. Bottom plate (can fix each movable bracket to form a cylinder).

[0042] Detailed list of tooling components: In this embodiment, three to six parallel vertical arc-shaped plates are selected as four pieces, namely movable brackets No. 1 to No. 4: the lower end of each arc-shaped plate can be fixed to a flange-shaped base plate in a radially adjustable manner: first, screw the three top plate screws 9 into the lower top plate 4, that is, the lower disc, and place the small end (smaller diameter end) of the flange-shaped cone surface of the lower top plate 4 upward in the middle of the base plate 21, screw one end of the pull rod 7 into the center threaded hole of the lower top plate 4, and lock it with a nut 5.

[0043] Insert two locating pins 19 into the pin holes of the bottom plate 21, insert each parallel vertical arc-shaped plate (bottom) into the locating pin hole on the No. 1 fixed bracket 2 onto the locating pin 19, and fix the No. 1 fixed bracket 2 to the bottom plate 21 with screw four 20; screw a telescopic screw 14 into the threaded hole at one end of the No. 1 movable bracket 2 with the T-slot and screw it in a proper distance, insert the two guide keys 12 into the T-slot below the No. 1 movable bracket, and place this assembly on the bottom plate 21 so that the guide keys 12 are stuck into the corresponding key slots on the bottom plate 21, adjust the position of the movable bracket, and fix the guide keys 12 to the bottom plate 21 with screw one 13, thereby completing the installation of the No. 1 movable bracket; each parallel vertical arc-shaped plate bottom is installed in this way;

[0044] Insert the center hole of the upper pressure plate (upper disc) 3 into the pull rod 7. Note that the small end of the conical surface of the upper pressure plate 3 is facing the bottom plate 21. Place the washer 8 on the pull rod 7 extending out of the upper pressure plate 3 and screw the nut 6 onto the pull rod 7.

[0045] Move the telescopic stopper with the grooved surface away from the center of the bottom plate, with the opening section facing the bottom plate. Each telescopic stopper is installed in the corresponding groove on the bottom plate 21 with screw two (these grooves correspond to the position of each parallel vertical arc-shaped plate (bottom) respectively), and fix the height limit block to the bottom plate 21 with screw three to complete the assembly.

[0046] The use process of processing tooling device:

[0047] First, unscrew nut 2 6, remove washer 8, remove the upper pressure plate 3, confirm that the small end of the conical surface of the lower top plate 4 is flush with or slightly lower than the upper plane of the bottom plate 21, then remove screw 2 15 and remove the height limit block 18. Take four parallel vertical arc-shaped plates (movable brackets No. 1 to 4) to form a whole cylindrical tube as an example: replace the corresponding telescopic stoppers 16 (3 in total) at the circumferential middle positions of the No. 2 movable bracket 10, the No. 3 movable bracket 13 and the No. 4 movable bracket 1, so that the end of the telescopic stopper 16 with the groove faces the center of the bottom plate, and the round head end of the telescopic screw 14 corresponding to the telescopic stopper 16 is just stuck in the groove of the telescopic stopper 16 (as shown in the figure). Figure 5), insert the hexagonal wrench into the hexagonal hole at the round end of the telescopic screw 14, rotate the hexagonal wrench, and push the second movable bracket 10, the third movable bracket 13 and the fourth movable bracket 1 to the center direction of the bottom plate 21 by an appropriate distance such as Figure 6 , forming Figure 7 status.

[0048] At this time, it can be seen that the No. 4 movable bracket 1 and the No. 2 movable bracket 10 are offset more toward the center of the circle, and the No. 3 movable bracket 11 is offset relatively less toward the center of the circle. The relatively small distance is still larger than the inner cavity of the workpiece to ensure that the workpiece can be smoothly loaded (accommodated) into the four parallel vertical arc-shaped plates that constitute the cylinder of the tooling, and there is a certain amount of space for movement when the arc-shaped plates are not adjusted into place.

[0049] Place the workpiece with the (flange-like) angle control edge facing downward into the fixture (four parallel vertical arc-shaped plates). Pay attention to the angle direction of the workpiece, place the workpiece to the bottom, and insert the locating pins into the eccentric angle holes on the angle control edge and the eccentric locating pin slots on each fixed bracket in sequence (such as Figure 7 )Inside.

[0050] Pull each movable bracket away from the center of the circle to the appropriate position (pull it away from the center of the circle to the appropriate position 0), and insert the positioning pin into the other eccentric angular hole of the angular control side (such as Figure 3 ) and eccentric positioning pin slots (such as Figure 7 ) within. Fix the height limit block 18 on the bottom plate 21 with screw three 17. Pay attention to the gap between the height limit boss of the height limit block 18 and the workpiece. Ensure that the workpiece has a certain amount of space for movement (such as Figure 9 ). Make the round end of the telescopic screw 14 close to the movable bracket where it is located.

[0051] Use an Allen wrench to rotate the top plate screw 9 downwards and lift the lower top plate (lower disc) 4. When the workpiece is lifted up, the cam 7 is rotated to move the upper and lower plates 4 downwards, so that the workpiece is tightened and the inner wall surface of the workpiece is fitted with the outer wall surface of each movable bracket. Use a feeler gauge to check the gap between the fitting surfaces. When the requirements are met, the cam 7 can be tightened again.

[0052] After the tooling is assembled from the parts, it forms a complete unit with the workpiece. After the workpiece is fixed vertically on the gantry of the machining center, the five-axis machining center is programmed to machine the workpiece's external shape, specifically the integrated thin tube structure with 6mm thick ribs and 1mm thick barrel wall. After machining, the cylindrical shape is cut through arcs to form two oblique-cut cylindrical workpieces.

[0053] The process of using tooling to eliminate gaps in workpieces that are deformed after processing: No matter how the workpiece deforms after the inner cavity of the workpiece is processed, the inner cavity of the entire workpiece is ultimately supported by the fixed brackets. Since the four brackets are made of cast iron and are assembled and processed at one time, the curved surface that fits the inner cavity of the workpiece can be achieved with a very precise size, thus ensuring that no matter how the part is deformed, it can ultimately be supported to the required contour range by the tooling.

[0054] Tooling Machining: A five-axis machining center (machine tool) machines the outer shapes of all brackets to the dimensions required by the workpiece cavity. Finally, a vertical lathe machines the upper and lower conical surfaces of the four brackets (extensions of the cylindrical barrel), ensuring concentricity between the conical surface and the outer contour, thus completing the tooling. The tooling is disassembled, plied, deburred, cleaned, and then assembled as required.

[0055] To ensure and measure the wall thickness of parts, after the workpiece is installed, the inner cavity of the workpiece is already in the theoretical position allowed by the tolerance. At this time, the outer surface can be processed by correcting the workpiece reference outer circle. The workpiece can be processed according to the process of rough machining, semi-finishing and finishing. The size requirements of the parts can be guaranteed by machining according to the theoretical value. At the same time, an ultrasonic thickness gauge can be used to perform real-time inspection of the parts during the machining process to ensure the qualification of the workpiece.

[0056] 3. Assembly process of processing equipment

[0057] First, screw the three top plate screws 9 into the lower top plate 4, place the small end of the conical surface of the lower top plate 4 facing upward in the middle of the bottom plate 21, so that its upward surface is basically flush with or slightly lower than the upper surface of the bottom plate 21, screw one end of the pull rod 7 into the center threaded hole of the lower top plate 4, and lock it with nut 5 to prevent it from loosening during use.

[0058] Insert the two positioning pins 19 into the pin holes of the base plate 21, insert the positioning pin holes on the No. 1 fixing bracket 2 into the positioning pins 19 and fix the No. 1 fixing bracket 2 to the base plate 21 with screws 20 to complete the installation of the No. 1 fixing bracket 2.

[0059] Screw a telescopic screw 14 into the threaded hole at one end of the T-slot of the No. 2 movable bracket 10 and screw it in an appropriate distance. Insert the two guide keys 12 into the T-slot below the No. 2 movable bracket 10, and place this assembly on the base plate 21 so that the guide keys 12 are stuck into the corresponding key slots on the base plate 21. Adjust the position of the No. 2 movable bracket 10 and fix the guide keys 12 to the base plate 21 with screws 13, thereby completing the installation of the No. 2 movable bracket 10.

[0060] In the same way, screw a telescopic screw 14 into the threaded hole at one end of the T-slot of the No. 3 movable bracket 11 and screw it in an appropriate distance. Insert the two guide keys 12 into the T-slot below the No. 3 movable bracket 11, and place this assembly on the base plate 21 so that the guide keys 12 are stuck into the corresponding key slots on the base plate 21. Adjust the position of the No. 3 movable bracket 11 and fix the guide keys 12 to the base plate 21 with screws 13, thereby completing the installation of the No. 3 movable bracket 11.

[0061] Similarly, screw a telescopic screw 14 into the threaded hole at one end of the T-slot of the No. 4 movable bracket 1 and screw it in an appropriate distance. Insert the two guide keys 12 into the T-slot below the No. 4 movable bracket 1. Place this assembly on the base plate 21 so that the guide keys 12 are stuck into the corresponding key slots on the base plate 21. Adjust the position of the No. 4 movable bracket 1 and fix the guide keys 12 to the base plate 21 with screws 13, thereby completing the installation of the No. 4 movable bracket 1.

[0062] Insert the center hole of the upper pressing plate 3 into the pull rod 7. Note that the small end of the conical surface of the upper pressing plate 3 is facing the bottom plate 21. Place the washer 8 on the pull rod 7 extending out of the upper pressing plate 3 and screw the nut 6 onto the pull rod 7.

[0063] The main body of the processing device has been installed. Now install the accessories.

[0064] Position the three telescopic stoppers 16 with the grooved surface facing away from the center of the base plate and the open end facing base plate 21. Install each one into its corresponding groove on base plate 21 using two second screws 15 (these grooves correspond to the positions of the telescopic screws 14 screwed into movable brackets 10, 11, and 1). Secure height limiter 18 to base plate 21 using screws 17. Complete the assembly.

[0065] 4. Usage of processing equipment

[0066] First, unscrew the nut 2 6, take off the washer 8, remove the upper pressure plate 3, confirm that the small end of the conical surface of the lower top plate 4 is flush with or slightly lower than the upper plane of the bottom plate 21, then remove the screw 2 15 and remove the height limit block 18, and replace the telescopic stopper 16 of the No. 2 movable bracket 10, the No. 3 movable bracket 13 and the No. 4 movable bracket 1 in the middle of the circumference (a total of 3 places), so that the end of the telescopic stopper 16 with the groove faces the center of the bottom plate, and the round head end of the telescopic screw 14 corresponding to the telescopic stopper 16 is just stuck in the groove of the telescopic stopper 16 (such as Figure 5 ), insert the hexagonal wrench into the hexagonal hole at the round end of the telescopic screw 14, rotate the hexagonal wrench, and push the second movable bracket 10, the third movable bracket 13 and the fourth movable bracket 1 to the center direction of the bottom plate 21 by an appropriate distance such as Figure 6 , forming Figure 7 status.

[0067] 1. Movable Bracket No. 4, 2. Fixed Bracket No. 1, 3. Upper Pressure Plate, 4. Lower Top Plate, 5. Nut 1, 6. Nut 2, 7. Pull Rod, 8. Washer, 9. Top Plate Screw, 10. Movable Bracket No. 2, 11. Movable Bracket No. 3, 12. Guide Key, 13. Screw 1, 14. Telescopic Screw, 15. Screw 2, 16. Telescopic Stop, 17. Screw 3, 18. Height Limit Block, 19. Dowel Pin, 20. Screw 4, 21. Bottom Plate (holds the movable brackets together to form a cylinder). Grooved End 30, Telescopic Screw Round End 31; Offset Dowel Pin Groove 32; Height Limiting Boss 33.

[0068] At this time, it can be seen that the No. 4 movable bracket 1 and the No. 2 movable bracket 10 are offset more toward the center of the circle, and the No. 3 movable bracket 11 is offset relatively less toward the center of the circle, but this relatively small distance must be greater than the difference between the maximum circle and the minimum circle of the workpiece cavity to ensure that the workpiece can be smoothly loaded into the tooling and have a certain amount of space for movement.

[0069] Place the workpiece with the angular control side facing downwards into the fixture, pay attention to the angular direction of the workpiece, put the workpiece to the bottom, and insert a positioning pin into the eccentric angular hole of the angular control side (such as Figure 6 ) and the eccentric positioning pin groove of the No. 1 fixing bracket 2 (such as Figure 7 )inside.

[0070] Replace the surface of each of the telescopic stoppers 16 at the circumferential middle positions of the second movable bracket 10, the third movable bracket 13 and the fourth movable bracket 1 (a total of 3 positions), so that the end of the telescopic stopper 16 with the groove is away from the center of the bottom plate, and the round end of the telescopic screw 14 corresponding to the telescopic stopper 16 is just stuck in the groove of the telescopic stopper 16 (as shown in the figure). Figure 8), insert the round end of the telescopic screw 14 with an inner hexagonal wrench and rotate it. First, pull the third movable bracket 11 away from the center of the circle to the appropriate position, and insert a positioning pin into the other eccentric angular hole of the angular control side (such as Figure 3 ) and the eccentric positioning pin groove of the third movable bracket 11 (such as Figure 7 ) in. Then use the same method to pull the second movable bracket 10 and the fourth movable bracket 1 away from the center of the circle to the appropriate position 0;

[0071] Fix the height limit block 18 on the bottom plate 21 with screws 17. Pay attention to the gap between the height limit boss of the height limit block 18 and the workpiece to ensure that the workpiece has a certain amount of space for movement (such as Figure 9 ).

[0072] Remove the locking screws 2 15 on the three telescopic stops 16, and remove the telescopic stops 16, screw the three telescopic screws 14 into the No. 2 movable bracket 10, No. 3 movable bracket 13 and No. 4 movable bracket 1 in the direction of the center of the circle, so that the round head ends of the telescopic screws 14 are tightly attached to their respective movable brackets.

[0073] Use an Allen wrench to rotate the three top plate screws 9 downward to lift the lower top plate 4. In the process of lifting the lower top plate 4, the inclined surface of its circumference will first contact the lower inclined surfaces of the No. 2 movable bracket 10, No. 3 movable bracket 13 and No. 4 movable bracket 1. At this time, pay attention to the order and amount of rotating the top plate screws 9 to control the level of the lower top plate 4, and try to make the lower top plate 4 rise slowly and evenly in the vertical direction. When the lower top plate 4 is lifted until its inclined surface contacts the lower inclined surface of the No. 1 fixed bracket 2, No. 2 movable bracket 10, No. 3 movable bracket 13 and No. 4 movable bracket 1, stop rotating the top plate screws 9. At this time, the No. 1 fixed bracket 2, No. 2 movable bracket 10, No. 3 movable bracket 13 and No. 4 movable bracket 1 have contacted the workpiece, but are not in contact with the inner wall surface of the workpiece. At this time, insert the center hole of the upper pressure plate 3 into the pull rod 7. Note that the small end of the conical surface of the upper pressure plate 3 is facing the bottom plate 21. At this time, the circumferential conical surface of the upper pressure plate 3 is in contact with the No. 1 fixed bracket 2, No. 2 movable bracket 10, No. 3 movable bracket 13 and No. 4 movable bracket 1, pay attention to ensure the level of the upper pressure plate 3, put the washer 8 on the pull rod 7 extending from the upper pressure plate 3, screw the nut 2 6 into the pull rod 7, and by continuously screwing the nut 2 6 into the pull rod 7, the upper pressure plate 3 is continuously downward and the lower top plate 4 is continuously rising (the lower top plate 4 is tightly connected with the pull rod 7 through the nut 1 5), and then through the interaction between the upper pressure plate 3 and the lower top plate 4 and the conical surfaces of the No. 1 fixed bracket 2, No. 2 movable bracket 10, No. 3 movable bracket 13 and No. 4 movable bracket 1, the No. 2 movable bracket 10, No. 3 movable bracket 13 and No. 4 movable bracket 1 are continuously moved away from the center of the circle, and the workpiece is slowly tightened so that the inner wall surface of the workpiece fits with the outer wall surface of the No. 1 fixed bracket 2, No. 2 movable bracket 10, No. 3 movable bracket 13 and No. 4 movable bracket 1, and the gap of the fitting surface is checked with a feeler gauge. When the requirement is met, the nut 2 6 can be no longer tightened.

[0074] Through the weight reduction groove on the upper pressure plate 3, use the inner hexagonal wrench to return the three top plate screws 9 to their original position. Figure 10 .

[0075] 5. The inner cavity of batch-produced parts is inconsistent (tolerance range type), the workpiece is deformed after processing, and the process of using tooling to eliminate the gap.

[0076] 6. Such as Figure 11 As shown, it can be clearly seen that no matter how the workpiece deforms after the inner cavity of the workpiece is processed, the inner cavity of the entire workpiece is ultimately supported by the No. 1 fixed bracket 2, the No. 2 movable bracket 10, the No. 3 movable bracket 11 and the No. 4 movable bracket 1. Since the four brackets are made of cast iron (welded) and are processed in one go after being combined, the curved surface that fits the inner cavity of the workpiece can be made to a very precise size, thereby ensuring that no matter how the part is deformed, it can eventually be supported to the required contour range by the tooling. Furthermore, as Figure 11As you can see, when nut 2 (6) is continuously tightened, lower top plate (4) moves upward and upper pressure plate (3) moves downward. Through the action of the conical surfaces of lower top plate (4) and upper pressure plate (3), the three movable brackets all move outward, thus continuously tightening and compacting the workpiece until the required dimensional profile is achieved. During this process, the deformation of the part is supported by the brackets back to the theoretical state, and the tolerance of the inner cavity machining is also divided into sections to fit the theoretical surfaces of the four brackets. This eliminates the impact of inconsistent inner cavities (tolerance range) of batch-produced parts and deformation of the workpiece after machining on part production.

[0077] Figure 11 Middle: the outer conical surface 34 of the upper top plate and the outer conical surface 35 of the lower top plate.

[0078] 7. Ensure and measure the wall thickness of parts by Figure 11 Through calibration, it can be determined that when the workpiece is installed, the inner cavity of the workpiece is already in the theoretical position allowed by the tolerance. At this time, the outer surface can be processed by correcting the workpiece reference outer circle. The workpiece can be processed according to the process of rough machining, semi-finishing and finishing. Machining according to the theoretical value can ensure the size requirements of the parts. At the same time, an ultrasonic thickness gauge can be used to perform real-time inspection of the parts during the machining process to ensure the qualification of the workpiece.

[0079] 8. Some requirements for tooling. The core requirement of this tooling is that the required contour dimensions must be achieved when the four brackets are stretched out. Therefore, after assembling the No. 1 fixed bracket with the base plate 21 through two locating pins 19, use 6 screws 4 19 to fix it to the base plate 21, and then pass the two guide keys 12 into the T-slot at the lower end of the No. 4 movable bracket, and insert the guide key part of this group that is higher than the lower surface of the No. 4 movable bracket 1 into the corresponding slot of the base plate 21. After adjusting the appropriate position, use 2 screws 13 to fix it to the base plate 21, and then adjust the No. 4 movable bracket 1 to the appropriate position and press it to the base plate 21 with a pressure plate. The same method is used to fix the No. 2 movable bracket 10 and the No. 3 movable bracket 11 to the base plate 21, thus forming a whole. The upper machine tool will process the outer shape of the four brackets to the size required by the workpiece inner cavity, and finally the upper vertical lathe will process the upper and lower conical surfaces of the four brackets in place to ensure the concentricity of the conical surface and the outer contour surface, thereby completing the tooling processing. Disassemble the tooling, trim the burrs with pliers, clean the tooling, and then assemble the tooling as required.

Claims

1. A method for processing an ultra-thin-wall casing of an aircraft engine special-shaped tail nozzle, characterized in that: The two oblique cylindrical workpieces are assembled into a complete cylindrical shape by the oblique edges of the two workpieces; an extension section is added to the middle of the cylindrical workpiece, a transition section at the upper end and an angular control edge at the lower end are added, and an offset positioning pin hole is machined on the angular control edge for standby use; According to the rough turning of the inner and outer shapes of the cylindrical parts, rough milling of the cylindrical cavity, vacuum tempering, turning of the outer circle reference and upper and lower end faces of the cylindrical parts, and fine milling of the inner cavity; A tooling device is provided, which is a cylindrical tube with an outer diameter equal to the inner diameter of the cylindrical part. The cylindrical tube is composed of three to six parallel vertical arc-shaped plates. A disc is embedded in the upper and lower ends of the cylindrical tube. Holes are evenly arranged in pairs in the center or on the edges of the upper and lower discs. A fixed pull rod is provided between the holes in the center of the upper and lower discs or in pairs. The fixed pull rod is fixed to the upper and lower disc surfaces with screws and nuts. The upper and lower edges of the cylindrical tube are provided with upward or downward setback angles at the contact points with the upper and lower discs. The angle between the setback angle and the vertical line is 2-15 degrees. The lower end of each arc-shaped plate can be fixed to a flange-shaped bottom plate in a radially adjustable manner. The upper disc and the lower disc are respectively an upper pressure plate and a lower top plate. After being assembled with the cylindrical part, the fixture is tightly integrated with the workpiece as the inner lining to form a whole. After the cylindrical part is fixed vertically on the table of the machining center, the outer shape of the cylindrical part is machined by programming on the five-axis machining center to produce an integrated thin cylindrical structure with 6mm thick reinforcement ribs and 1mm thick barrel wall. After the machining is completed, the cylindrical barrel is cut by arc programming to form two cylindrical workpieces divided by an oblique line. The vertical arc-shaped plate of the cylindrical barrel of the tooling device is composed of the first and second groups of four movable bracket arc-shaped plates, which are assembled alternately. The central angle of the two movable brackets in the first group is 45°±15°, and the central angle of the two movable brackets in the second group is 135°±15°. The two alternating groups of four movable brackets are No. 1, No. 2, No. 3 and No. 4 movable brackets: The fixed bracket is fixed to the flange-shaped base plate by two pins on one side: insert the two locating pins into the pin holes of the base plate, put the locating pin holes on the No. 1 fixed bracket onto the locating pins and fix the No. 1 fixed bracket to the base plate with six screws to complete the installation of the No. 1 fixed bracket. The lower end of the arc-shaped plate of the movable bracket is radially adjusted by a guide bar and is fixed to a flange-shaped base plate by a pressure plate: a telescopic screw is screwed into the threaded hole at the end of the T-slot of the No. 2 movable bracket, that is, the lower end of the arc-shaped plate, and screwed in an appropriate distance, and the two guide keys are inserted into the T-slot below the movable bracket. The assembly is placed on the base plate so that the guide keys are stuck in the corresponding key slots on the base plate, the position of the No. 2 movable bracket is adjusted, and the guide keys are fixed to the base plate with two screws, thereby completing the installation of the No. 2 movable bracket, and the installation of the No. 3 movable bracket and the No. 4 movable bracket is completed by analogy; Adjust the No. 2 to 4 movable brackets to the appropriate position through the telescopic screw, then screw the three top plate screws into the lower top plate, place the small end of the conical surface of the lower top plate upwards in the middle of the bottom plate, so that its upward surface is basically flush with or slightly lower than the upper surface of the bottom plate, screw one end of the pull rod into the central threaded hole of the lower top plate, and lock it with a nut to prevent it from loosening during use; then adjust the No. 2 to 4 movable brackets to the appropriate position through the telescopic screw, place the angular control side of the workpiece downwards, install the four parallel vertical arc-shaped plates of the tooling device inside the part, pay attention to the angular direction of the workpiece, put the workpiece to the bottom, and insert the locating pins into the eccentric angular hole on the angular control side and the eccentric locating pin slot on the No. 1 fixed bracket in sequence; Pull the No. 3 movable bracket away from the center of the circle to a suitable position through the telescopic screw, that is, pull it in the direction away from the center of the circle, and insert the positioning pin into the other eccentric angular hole and the eccentric positioning pin groove of the angular control side in sequence; then pull the No. 2 and No. 4 movable brackets away from the center of the circle to a suitable position through the telescopic screw, that is, pull them in the direction away from the center of the circle, and fix the height limit block to the base plate with screw three, paying attention to the gap between the height limit boss of the height limit block and the workpiece to ensure that the workpiece has a certain amount of movable space; rotate the telescopic screw so that its round head end is tightly attached to its respective movable bracket; When the upper plate is lifted, the lower plate is tightened so that the inner wall surface of the cylindrical workpiece fits the outer wall surface of each movable bracket, and the gap between the fitting surface and the workpiece is checked with a feeler gauge. When the gap between the fitting surface and the workpiece is reached, the nut 2 is no longer tightened.

2. The method for processing an ultra-thin-wall casing of an aircraft engine special-shaped tail nozzle according to claim 1, characterized in that: During the processing, ultrasonic thickness gauge is used to inspect parts in real time to ensure the quality of the workpiece.

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