Pneumatic skin shape correcting device and method

Abstract

According to the pneumatic skin shape correcting device and method, a female die and a base of the shape correcting device have an interlocking function in a natural state, and the shape correcting device has the functions of providing ultrahigh pressure edge tonnage and releasing ignition sparks by means of magnetic force transmission under the condition that a coil is powered on; explosive is placed in the shape correcting device, a coil is electrified to magnetize the shape correcting device, magnetic force transmits magnetic induction to promote the magnetic induction switch to discharge and detonate the explosive, and high-temperature and ultrahigh-pressure gas is instantly generated to impact the inner surface of the semi-finished product; and after explosion, the coil is continuously electrified, the female die and the base are magnetized to generate ultrahigh pressure edge tonnage to seal explosion heat energy, and the high-pressure retention time is prolonged, so that inner surface layer materials of a semi-finished product are compacted through hot pressing, the grain ultrafine area is microscopically shrunk, and surface tension for counteracting springback is formed. The method has the remarkable advantages of high load, low energy consumption, high speed and the like, and can overcome the problem that the large pneumatic aluminum alloy skin is limited by a series of factors such as the solid solution inoculation period, the equipment table top and the tonnage and is poor in die attaching precision.

Description

Technical Field

[0001] The present application belongs to the field of plastic processing technology, and specifically relates to a pneumatic skin shaping device and method. Background Art

[0002] In order to meet the needs of forming complex thin-walled components and improving service life, most aluminum alloys need to be quickly heated at about 500°C and then quickly cooled in room temperature water after forming. The severe deformation caused by rapid heating and rapid cooling has become a major problem that restricts the improvement of mold accuracy and yield rate of thin-walled components; the reason is that the incubation period for maintaining excellent plasticity after solid solution is generally 0.5 hours. If the prescribed time is exceeded, the plasticity will drop sharply due to aging hardening, the difficulty of shape correction will increase exponentially and it is easy to crack.

[0003] At present, the main operation mode of sheet metal heat treatment correction is: first use a rubber plate to quickly whip the area where the stress is seriously concentrated in the part after solid solution, and then use a metal hammer to knock it to further even out the stress distribution. The common problems are as follows: First, rubber whipping or hammer knocking belongs to point-by-point and domain-by-domain correction. The defects such as looseness and agitation of thin-walled parts always alternate in different correction intervals, which is inefficient. Second, relying on skills and experience, the correction sequence and correction strength of the same product are different due to the obvious differences in operator skills and solid solution deformation degree; especially large and complex thin-walled parts solid solution deformation correction mold bonding is more difficult, and it is easy to be improperly corrected or even the mold bonding effect becomes worse and worse.

[0004] The essence of shape correction is to use the uniform distribution of internal forces to evenly disperse a more serious macro defect into multiple extremely small approximate micro defects, so that the finished parts are as close to the theoretical profile as possible under a reasonable stress maintenance state. The formation mechanism of defects such as macro loosening, agitation, and distortion after shape correction mainly causes uneven wall thickness distribution. In order to solve the problem of shape correction of thin-walled parts, the relative technology adopts a rigid shape correction method to make the wall thickness uniform. Its essence is to use the full-surface matching convex and concave dies to rigidly shape the parts, so as to minimize the wall thickness difference of the heat-treated semi-finished products. However, the common problems of the above technologies are as follows: First, the profile needs to be matched with the convex and concave dies with high precision at the same time, and the cost of process equipment is high; second, the shaping thick extrusion has extremely high requirements on the tonnage of the equipment. For large-sized parts, it is often difficult to achieve the expected effect due to insufficient equipment table or tonnage. Summary of the invention

[0005] Purpose of the invention: To provide a high-energy shaping device for a pneumatic skin and a method for using the same, which utilizes the high energy at the moment of explosion to refine the grains of the inner surface material of the semi-finished product in a hot and high-pressure environment, and shrink the inner surface to offset the deformation strengthening and solution treatment rebound. At the same time, the magnetic material device is electromagnetically induced, and the device components are in close contact to provide ultra-high tonnage clamping force, thereby overcoming the problem that ultra-large thin-walled parts cannot be mechanically shaped due to the limitations of the equipment table and tonnage.

[0006] In a first aspect, the present application provides a pneumatic skin shaping device, the shaping device comprising a die, a base, a self-locking shaft pin, and a clamping arm;

[0007] The die is a double-step structure, the first step is larger than the second step, guide holes are provided on the left and right sides of the first step, the lower surface of the second step is an annular pressing surface, which matches the upper surface of the semi-finished flange edge, and the inner side of the annular pressing surface is an effective working surface, which matches the outer surface of the aerodynamic skin;

[0008] The base is a rigid flat plate structure, with guide columns matching the guide holes of the die on the left and right sides of the base, concentric through holes on the front and rear positioning bosses of the base, and an anti-rotation lock groove on one side of the concentric through holes;

[0009] The self-locking shaft pin matches the diameter of the concentric through hole of the base, the length of the self-locking shaft pin is greater than the spacing between the two sides of the base boss, one end of the self-locking shaft pin is provided with an annular groove, an annular ring is suspended in the annular groove, the inner diameter of the annular ring is greater than the diameter of the self-locking shaft pin, and the other end of the self-locking shaft pin is provided with an anti-rotation boss, which matches the anti-rotation lock groove of the rigid base;

[0010] The clamping arm is a hook-shaped structure, and a positioning hole matching the diameter of the self-locking shaft pin is provided at the straight arm end, and the other end is suspended on the top surface of the first step of the die; the self-locking shaft pin passes through the concentric through holes of the clamping arm and the base to fix the clamping arm to the base, and the die and the base can be interlocked and unlocked at will by rotating the clamping arm along the self-locking shaft pin.

[0011] Preferably, the top surface of the first step of the die and the free end of the clamping arm are respectively provided with a rectangular avoidance groove and a rectangular boss, and the depth of the rectangular avoidance groove is greater than the rectangular boss; when the die and the base are in a locked state, the rectangular boss of the clamping arm is embedded in the rectangular avoidance groove of the die; the top surface of the first step of the die is also provided with a plurality of exhaust holes connected to the effective working surface.

[0012] Preferably, the die and the base are made of magnetic materials, and an annular groove is provided on the outer side of the second step of the die. A number of low-resistance coils are wound in the annular groove. When the coils are connected to a DC power supply, the die is magnetized and pressed against the base. The upper surface of the base is provided with a contour larger than a lower limit surface of the semi-finished flange edge, and the depth of the lower limit surface is equal to the theoretical wall thickness of the aerodynamic skin, and the matching gap between the outer plane area of ​​the lower limit surface and the annular pressing surface of the die is zero.

[0013] Preferably, the base is further provided with a center hole within the lower limit surface, a U-shaped groove is provided at the bottom edge of the center hole, a battery slot connected to the center hole is provided next to the center hole, and a rigid connecting bridge is installed above the center hole. The connecting bridge is made of non-magnetic material, and a magnetic induction switch is fixed on the connecting bridge.

[0014] Preferably, the magnetic induction switch is composed of a spring and an I-shaped iron rod; when the current is lower than a specified value, the magnetic induction switch is in a power-off state, and adjusting the current coil to generate a changing magnetic field can preheat the pneumatic skin semi-finished product; when the current is higher than a specified value, the die strongly magnetizes the I-shaped iron rod and descends through the magnetic compression spring, forming a closed loop with the battery to release electric sparks; when the coil is in a power-off state, the base demagnetization spring recovers, and the I-shaped iron rod rising circuit is automatically cut off.

[0015] In a second aspect, the present application also provides a method for aerodynamic skin correction, the method comprising:

[0016] Semi-finished product production: Cut the flange edge of the aerodynamic skin semi-finished product according to the contour of the lower limit surface of the base, and then perform solid solution heat treatment on the semi-finished product after cutting;

[0017] Shape correction device and installation and debugging: first place a small amount of explosives in the center hole of the base, and place the die on the base using the guide hole of the die and the guide column of the base to position it. Rotate the clamping arm inward to make the die and the base interlock automatically, and then pass the electromagnetic die through the coil to make the die press the base. The magnetic force of the base attracts the I-shaped iron rod to form a closed loop to release electric sparks, and complete the magnetic induction sensitivity test of the magnetic induction switch;

[0018] Explosive shaping: Explosives are placed in the center hole of the base, the semi-finished product is fixed between the die and the base to press the flange edge, and then the coil is energized to magnetize the die to press the base. At the same time, the magnetic induction switch discharges and detonates the explosives, so that the inner surface material of the semi-finished product is instantly heated and high-pressured to ultra-fine the grains, and the inner surface shrinks to offset the deformation strengthening and solution treatment rebound;

[0019] Pressure-maintaining unloading: The coil is continuously energized, and the die and the base seal the semi-finished product and the heat energy of the explosion, allowing the semi-finished product to cool naturally under the hot, high-pressure and shape-maintaining state. The holding arm is rotated outward to raise the die and separate the semi-finished product from the base.

[0020] Preferably, the magnetic induction test method of the magnetic induction switch is: a small amount of low-ignition-point explosive is placed between the base and the I-shaped iron rod, the coil current is gradually increased to close the magnetic induction switch to discharge and ignite the explosive, smoke discharge is observed from the exhaust hole of the die, and the extreme current passed into the coil when the explosive is ignited is recorded.

[0021] Preferably, a lead sheet block is placed in the rectangular avoidance groove on the top surface of the die, and the thickness of the lead sheet block matches the distance between the rectangular boss of the clamping arm and the bottom surface of the rectangular avoidance groove.

[0022] Preferably, a small amount of low-ignition-point explosive is placed in the middle of the center hole of the base, and a high-ignition-point high explosive is placed in the U-shaped groove of the center hole of the base; before the explosive is detonated, a changing current that is significantly lower than the detonation limit of the explosive is first passed through the coil, so that the coil generates a changing magnetic field to preheat the aerodynamic skin semi-finished product; when the explosive is detonated, a current that is significantly greater than the ignition limit of the explosive is passed through the coil.

[0023] Preferably, the calculation method of the amount of high explosive is: M = 850*K*V÷Q, 1≤k≤2;

[0024] Among them, M is the mass of the explosive, in kilograms; V is the volume of the die, in cubic meters; Q is the calorific value of the unit weight of the explosive; K is a coefficient related to the wall thickness, surface area, and shape of the part.

[0025] This application has the following technical effects:

[0026] The present application utilizes the high temperature and high pressure airflow of the explosion to impact the surface of the parts, which is equivalent to a huge rubber plate hitting multiple shaping areas at the same time, and has significant advantages such as uniform force and large load.

[0027] The shape correction method of the present application utilizes the energy released by the explosion of a very small amount of explosives to complete the instant shape correction of parts, which can avoid the disadvantages of hardening and cracking caused by the solid solution aging of aluminum alloys, and has significant advantages such as low energy consumption and high speed. The present application utilizes the instantaneous high temperature and high pressure environment to facilitate the ultra-fine organization of the heated surface material, thereby achieving a microscopic reduction in the internal surface area, which not only offsets the unloading rebound, but also improves the material performance effect.

[0028] This application utilizes the huge suction force generated by zero-gap contact of magnetized materials to overcome the problem of being unable to quickly calibrate large parts due to the limitations of existing equipment table and tonnage. Therefore, the use of the calibration device and calibration method of this application has the advantages of fast speed, strong force, and uniform force; it is not limited by equipment tonnage, has strong versatility, and is easy to promote. At the same time, it can also improve the mechanical properties of the calibration products. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of a semi-finished product of a typical aerodynamic skin applicable to this application;

[0030] Figure 2 It is a schematic diagram of the assembly structure of the shape correction device of the present application;

[0031] Figure 3 It is a schematic diagram of the rigid concave die structure of the shape correction device of the present application;

[0032] Figure 4 It is a schematic diagram of the rigid base structure of the shape correction device of the present application;

[0033] Figure 5 This is a schematic diagram of the assembly principle of the rigid base and the clamping arm of the shape correction device of the present application;

[0034] Figure 6 It is an enlarged schematic diagram of the working principle of the magnetic induction switch of the shape correction device of the present application;

[0035] Figure 7It is an enlarged schematic diagram of the assembly of the self-locking shaft pin and the clamping arm of the shape correction device of the present application;

[0036] Figure 8 It is a schematic diagram of the transverse section principle of the shape correction device of the present application;

[0037] Explanation of numbers in the figure: 1. aerodynamic skin, 2. flange edge, 3. semi-finished product, 4. die, 5. base, 6. self-locking shaft pin, 7. clamping arm, 8. first step, 9. second step, 10. guide hole, 11. pressing surface, 12. working surface, 13. guide column, 14. concentric through hole, 15. anti-rotation lock groove, 16. annular ring, 17. anti-rotation boss, 18. rectangular avoidance groove, 19. rectangular boss, 20. exhaust hole, 21. annular groove, 22. coil, 23. lower limit surface, 24. center hole, 25. battery slot, 26. connecting bridge, 27. magnetic induction switch, 28. spring, 29. I-shaped iron rod, 30. battery, 31. electric spark, 32. lead sheet block, 33. low ignition point explosive, 34. high explosive. DETAILED DESCRIPTION

[0038] It should be noted that the present application provides a shape correction device and a method for use in solid solution deformation of aerodynamic skins, which is particularly suitable for large aluminum alloy skins in a magnetic, thermal, and electric field coupling environment to improve the mold accuracy and shape correction efficiency of skin parts that are difficult to correct after solid solution.

[0039] See attached Figure 1 , the pneumatic skin 1 is one of the typical objects to which this application applies. The semi-finished product 3 of the pneumatic skin 1 is a three-dimensional thin shell structure with an annular flange edge 2 on all sides. In order to meet the purpose of forming and improving the service strength, aluminum alloy complex thin-walled components are all formed in the annealing state and then subjected to solution heat treatment processing; and the correction of deformation of aluminum alloy solution heat treatment is a common problem faced by all sheet metal parts. The existing correction means first use a rubber plate to quickly whip the newly quenched state parts in the area where stress is seriously concentrated, and then use a metal hammer to knock to further make the stress distribution uniform. The problems are as follows: rubber whipping or hammer knocking belongs to domain-by-domain and point-by-point correction, and defects such as loosening and agitation of thin-walled parts always alternate in different correction intervals, which is inefficient. After aluminum alloy solid solution, the correction needs to be completed within the incubation period to maintain plasticity. If the specified time is exceeded, the correction difficulty will increase exponentially due to aging hardening, and even cracking and scrapping may occur. Especially for large and complex thin-walled parts, due to the time limit of the solid solution incubation period of the material, it is easy to improperly correct the shape based on experience, and even the mold effect will become worse and worse.

[0040] In order to solve the above-mentioned problems existing in the solid solution heat treatment of large aerodynamic skin 1, the present application proposes a method for simultaneously bombarding the inner surface of the semi-finished product 3 with the huge energy released at the moment of explosion, so that the grains of the inner surface material of the semi-finished product 3 are ultra-fine in the hot and high-pressure environment, so as to achieve the purpose of inner surface shrinkage offset deformation strengthening and solid solution treatment rebound. The technical scheme of the high-energy shape correction device of the aerodynamic skin of the present application is as follows:

[0041] See attached Figure 2 -Attached Figure 8 The shape correction device comprises a rigid die 4, a base 5, a self-locking shaft pin 6, and a clamping arm 7. The die 4 is a double-step structure. The first step 8 is larger than the second step 9. The first step 8 is provided with guide holes 10 on both sides. The lower surface of the second step 9 is an annular pressing surface 11. The annular pressing surface 11 is aligned with the upper surface of the semi-finished flange 2. The inner side of the annular pressing surface 11 is an effective working surface 12. The effective working surface 12 matches the outer surface of the aerodynamic skin 1. The base 5 is a rigid flat plate structure. The base 5 is provided with guide columns 13 matching the die guide holes 10 on both sides. Concentric through holes 14 are provided on the front and rear positioning bosses of the base. An anti-rotation lock groove 15 is provided on one side of the concentric through hole 14. The self-locking pin 6 matches the diameter of the concentric through hole 14 of the base, the length of the self-locking pin 6 is greater than the spacing between the two sides of the boss of the base 5, one end of the self-locking pin 6 is provided with an annular groove, and an annular ring 16 is suspended in the annular groove, the inner diameter of the annular ring 16 is greater than the diameter of the self-locking pin 6, and the other end of the self-locking pin 6 is provided with an anti-rotation boss 17, which matches the anti-rotation lock groove 15 of the rigid base. The clamping arm 7 is a hook-shaped structure, and the straight arm end is provided with a positioning hole matching the diameter of the self-locking pin 6, and the other end is suspended on the top surface of the first step 8 of the die. The self-locking pin 6 passes through the clamping arm 7 and the concentric through hole 14 of the base, and the clamping arm 7 is fixed on the base 5. The clamping arm 7 can be rotated along the self-locking pin 6 to interlock and unlock the die 4 and the base 5 at will. In order to ensure the safety of the explosion, the main components of the correction device must meet the rigidity requirements, the mutual locking requirements between the components during the explosion, and the requirements for quick unlocking and unloading after correction.

[0042] See attached Figure 2 , Attachment Figure 3In order to avoid violent vibration at the moment of explosion, the clamping arm 7 rotates outward, causing the interlocking of the die 4 and the base 5 to fail. The top surface of the first step 8 of the die and the free end of the clamping arm 7 are respectively provided with a rectangular avoidance groove 18 and a rectangular boss 19, and the depth of the rectangular avoidance groove 18 is greater than the rectangular boss 19. When the die 4 and the base 5 are in a locked state, the rectangular boss 19 of the clamping arm is embedded in the rectangular avoidance groove 18 of the die. The purpose is that when the die 4 explodes, under the action of the guide hole 10 and the guide column 13, the die 4 only vibrates vertically, and the upward movement of the die 4 will only lock tighter. In order to avoid the semi-finished product 3 and the working surface 12 of the die 4 due to heat treatment deformation, the top surface of the first step 8 of the die is also provided with a plurality of exhaust holes 20 connected to the effective working surface; the purpose is to facilitate the smooth discharge of gas in the non-fitting area.

[0043] See attached Figure 2 , Attachment Figure 3 , Attachment Figure 8 In order to reduce the attenuation of the explosion energy, the die 4 and the base 5 are made of magnetic materials. An annular groove 21 is provided on the outer side of the second step 9 of the die. A number of low-resistance coils 22 are wound in the annular groove 21. The coils 22 are connected to a DC power supply, and the die 4 is magnetized and pressed against the base 5. In order to maximize the blanking force of the die 4 on the base 5, the upper surface of the base 5 is provided with a lower limit surface 23 with a contour larger than the semi-finished flange edge. The depth of the lower limit surface 23 is equal to the theoretical wall thickness of the aerodynamic skin 1, and the matching gap between the outer plane area of ​​the lower limit surface 23 and the annular pressing surface 11 of the die is zero. The purpose is to use the energized coil 22 to magnetize the die 4 and the base 5, and use the zero-gap contact between the die 4 and the base 5 to generate ultra-high pressure edge tonnage, extend the high temperature and ultra-high pressure residence time, and improve the shape correction and die-sticking effect.

[0044] See attached Figure 4 , Attachment Figure 5 , Attachment Figure 8 In order to facilitate the ignition of explosives in a completely sealed state, the base is further provided with a center hole 24 in the lower limit surface 23, a U-shaped groove is provided at the bottom edge of the center hole, a battery slot 25 connected to the center hole is provided next to the center hole 24, and a rigid connecting bridge 26 is installed above the center hole. The connecting bridge 26 is made of non-magnetic material, and a magnetic induction switch 27 is fixed on the connecting bridge. Its purpose is to isolate the detonation switch from the outside world and slow down energy attenuation.

[0045] See attached Figure 4 -Attached Figure 6In order to further ensure that the explosive is ignited in a completely sealed state, the magnetic induction switch 27 is composed of a spring 28 and an I-shaped iron rod 29; the power supply current connected to the coil 22 can be adjusted. When the current is lower than the specified value, the magnetic induction switch 27 is in a power-off state. The current coil produces a variable magnetic field to preheat the pneumatic skin semi-finished product 3; when the current is higher than the specified value, the die 4 strongly magnetizes the I-shaped iron rod 29 and descends through the magnetic compression spring 28, forming a closed loop with the battery 30 to release the electric spark 31; when the coil 22 is in a power-off state, the base demagnetization spring 28 is restored, and the I-shaped iron rod 29 rises and the circuit is automatically cut off. Its purpose is to use the device to magnetize the magnetic force transmission to ignite the explosive, realize the compression of the flange edge 2 and the explosion at the same time, maximize the utilization rate of the explosion energy, reduce the amount of explosives and ensure the safety of operation.

[0046] See attached Figure 1 -Attached Figure 8 The main operation steps and implementation points of the shape correction device of this application are as follows:

[0047] 1) Semi-finished product production: the flange edge 2 of the aerodynamic skin semi-finished product is cut according to the contour of the lower limit surface 23 of the base, and then the semi-finished product 3 after cutting is solution heat treated.

[0048] 2) Shape correction device and installation and debugging: first place a small amount of explosives in the center hole 24 of the base, position the die 4 on the base 5 using the guide hole 12 of the die and the guide column 13 of the base, rotate the clamping arm 7 inward to make the die 4 and the base 5 automatically interlock, then pass the electromagnetic die 4 through the coil 22 to make the die 4 press the base 5, the base 5 magnetically attracts the I-shaped iron rod 29 to form a closed loop to release the electric spark 30, and complete the magnetic induction sensitivity test of the magnetic induction switch 27.

[0049] 3) Explosive shaping: Explosives are placed in the center hole 24 of the base, and the semi-finished product is fixed between the die 4 and the base 5 to press the flange 2. The coil 22 is energized to magnetize the die 4 to press the base 5. At the same time, the magnetic induction switch 27 discharges and detonates the explosives, so that the inner surface material of the semi-finished product 3 is instantly refined in a hot and high-pressure environment, and the inner surface shrinks to offset the deformation strengthening and solution treatment rebound.

[0050] 4) Unloading under pressure: The coil 22 is continuously energized, and the die 4 and the base 5 seal the semi-finished product 3 and the heat energy of the explosion, so that the semi-finished product 3 is naturally cooled under the hot high pressure and shape-preserving state, and the clamping arm 7 is rotated outward to raise the die 4 to separate the semi-finished product 3 from the base 5.

[0051] See attached Figure 1 , Attachment Figure 3In order to alleviate the solid solution aging hardening of the semi-finished product 3, when the semi-finished product 3 is manufactured, the profile of the semi-finished product flange 2 is at least 5mm smaller than the profile of the lower limit surface 23 of the base. After the semi-finished product is dried by solid solution heat treatment, it is placed in an environment below -21°C for rapid cooling. The purpose of reducing the width of the flange 2 is to avoid the influence of solid solution deformation on positioning, and the purpose of low temperature refrigeration is to delay aging and ensure that the semi-finished product 3 is in the most plastic state after explosive correction.

[0052] See attached Figure 2 , Attachment Figure 8 When the shape correction device is installed and debugged, a lead sheet block 31 is placed in the rectangular avoidance groove 18 on the top surface of the die 4. The thickness of the lead sheet block 31 matches the distance between the rectangular boss 19 of the clamping arm and the bottom surface of the rectangular avoidance groove 18. The purpose is to use the soft but difficult to compress characteristics of the lead sheet to buffer the impact of the explosion energy on the shape correction device.

[0053] See attached Figure 2 , Attachment Figure 8 When debugging the shape correction device, the magnetic induction sensitivity test method of the magnetic induction switch 27 is as follows: low-ignition-point explosives are placed between the base 4 and the I-shaped iron rod 29, and the current of the coil 22 is gradually increased to close the magnetic induction switch to discharge and ignite the explosives, and smoke is observed to be discharged from the die exhaust hole 20. It should be noted that the purpose of debugging is to ensure that the device does not detonate explosives during the installation process, that is, the elastic force of the spring 28 cannot be too small, but the elastic force cannot be too large to avoid insufficient magnetic force of the base 5 to form a closed loop discharge. Therefore, only a very small amount of explosives needs to be placed, and a small current is passed through the coil 22 to ignite the explosives.

[0054] See attached Figure 6 , Attachment Figure 8 It should be noted that: in order to ensure the safety of transportation and storage of explosives, the greater the explosive power, the higher the ignition point. The ignition point of some high explosives can reach 500 degrees or even higher. A small amount of low-ignition-point explosive 33 is placed in the middle of the center hole 24 of the base, and a high-ignition-point high explosive 34 is placed in the U-shaped groove of the center hole of the base; before the explosive is detonated, a variable current significantly lower than the detonation limit of the explosive is first passed into the coil 22, so that the coil 22 generates a variable magnetic field to preheat the aerodynamic skin semi-finished product 3; when the explosive is detonated, a current significantly greater than the ignition limit of the explosive is passed into the coil 22. Its beneficial effects are as follows: First, it is convenient for high-ignition-point and high-power explosives to be ignited smoothly, improving operational reliability; second, preheating the semi-finished product facilitates slowing down the cooling speed and improving the shape correction and mold-sticking effect; third, it is convenient for the device to produce a higher pressure edge tonnage, improve the sealing effect and alleviate energy attenuation; fourth, it is convenient to minimize the amount of explosives and ensure operational safety.

[0055] In order to increase the correction effect and ensure safety, the amount of explosives should be controlled. When performing explosive correction, the calculation method for the amount of high explosives 34 is: M = 850*K*V÷Q, (recommended 1≤k≤2) where M is the mass of the explosive in kilograms; V is the volume of the die in cubic meters; Q is the calorific value of the unit weight of the explosive; K is the correlation coefficient with the wall thickness, surface area, shape, etc. of the part. It should be noted that the energy generated by the explosion theory causes the air in the die to rise in temperature in a short time without exceeding the solid solution temperature of the aluminum alloy. Considering that the high temperature and high pressure generated by the explosion heat are released in a very short time (a few ten-thousandths of a second), the actual ablation of the aluminum alloy material can be ignored. Properly increasing the amount of explosives can delay the residence time of the high temperature and high pressure of the explosion heat, increase the grain refinement ratio of the inner surface material of the semi-finished product 3, and further reduce the inner surface area of ​​the semi-finished product 3 to offset the rebound.

[0056] In other embodiments of the present application, a high-energy shaping device for pneumatic skin and a method for using the solid solution shaping device are provided. The die and base of the shaping device have an interlocking function in a natural state, and have the function of providing ultra-high pressure edge tonnage and releasing sparks by magnetic force transmission when the coil is energized; explosives are placed in the shaping device, and the coil is energized to magnetize the shaping device. The magnetic force transmission magnetic induction causes the magnetic induction switch to discharge and detonate the explosive, and instantly generates high temperature and ultra-high pressure gas to impact the inner surface of the semi-finished product; after the explosion, the coil is continuously energized, and the ultra-high pressure edge tonnage generated by magnetization between the die and the base seals the explosion heat energy, prolongs the high pressure residence time, and makes the inner surface material of the semi-finished product hot compacted, and the grain ultra-fine area shrinks microscopically to form a surface tension that offsets the rebound. The shaping device and shaping method of the present application have significant advantages such as high load, low energy consumption, and high speed, and can overcome the problem of poor mold accuracy of large aluminum alloy pneumatic skins restricted by a series of factors such as solid solution incubation period, equipment table, and tonnage.

Claims

1. A pneumatic skin correction device, characterized in that: The shape correction device comprises a die, a base, a self-locking shaft pin, and a clamping arm; The die is a double-step structure, the first step is larger than the second step, guide holes are provided on the left and right sides of the first step, the lower surface of the second step is an annular pressing surface, which matches the upper surface of the semi-finished flange edge, and the inner side of the annular pressing surface is an effective working surface, which matches the outer surface of the aerodynamic skin; The base is a rigid flat plate structure, with guide columns matching the guide holes of the die on the left and right sides of the base, concentric through holes on the front and rear positioning bosses of the base, and an anti-rotation lock groove on one side of the concentric through holes; The self-locking shaft pin matches the diameter of the concentric through hole of the base, the length of the self-locking shaft pin is greater than the spacing between the two sides of the base boss, one end of the self-locking shaft pin is provided with an annular groove, an annular ring is suspended in the annular groove, the inner diameter of the annular ring is greater than the diameter of the self-locking shaft pin, and the other end of the self-locking shaft pin is provided with an anti-rotation boss, which matches the anti-rotation lock groove of the rigid base; The clamping arm is a hook-shaped structure, and a positioning hole matching the diameter of the self-locking shaft pin is provided at the straight arm end, and the other end is suspended on the top surface of the first step of the die; the self-locking shaft pin passes through the concentric through holes of the clamping arm and the base to fix the clamping arm to the base, and the die and the base can be interlocked and unlocked at will by rotating the clamping arm along the self-locking shaft pin.

2. The shape correction device according to claim 1, characterized in that: The top surface of the first step of the die and the free end of the clamping arm are respectively provided with a rectangular avoidance groove and a rectangular boss, and the depth of the rectangular avoidance groove is greater than the rectangular boss; when the die and the base are in a locked state, the rectangular boss of the clamping arm is embedded in the rectangular avoidance groove of the die; the top surface of the first step of the die is also provided with a plurality of exhaust holes connected to the effective working surface.

3. The shape correction device according to claim 2, characterized in that: The die and the base are made of magnetic materials. An annular groove is provided on the outer side of the second step of the die. A number of low-resistance coils are wound in the annular groove. When the coils are connected to a DC power supply, the die is magnetized and pressed against the base. The upper surface of the base is provided with a contour larger than a lower limit surface of the semi-finished flange edge. The depth of the lower limit surface is equal to the theoretical wall thickness of the aerodynamic skin, and the matching gap between the plane area outside the lower limit surface and the annular pressing surface of the die is zero.

4. The shape correction device according to claim 3, characterized in that: The base is also provided with a center hole in the lower limit surface, a U-shaped groove is provided at the bottom edge of the center hole, a battery groove connected to the center hole is provided beside the center hole, and a rigid connecting bridge is installed above the center hole. The connecting bridge is made of non-magnetic material and a magnetic induction switch is fixed on the connecting bridge.

5. The shape correction device according to claim 4, characterized in that: The magnetic induction switch is composed of a spring and an I-shaped iron rod. When the current is lower than a specified value, the magnetic induction switch is in a power-off state. Adjusting the current coil to generate a changing magnetic field can preheat the pneumatic skin semi-finished product. When the current is higher than a specified value, the I-shaped iron rod of the die is strongly magnetized and descends through the magnetic compression spring, forming a closed loop with the battery to release electric sparks. When the coil is in a power-off state, the demagnetization spring of the base is restored, and the I-shaped iron rod rising circuit is automatically cut off.

6. A method for correcting the shape of an aerodynamic skin, characterized in that: The method comprises: Semi-finished product production: Cut the flange edge of the aerodynamic skin semi-finished product according to the contour of the lower limit surface of the base, and then perform solid solution heat treatment on the semi-finished product after cutting; Shape correction device and installation and debugging: first place a small amount of explosives in the center hole of the base, and place the die on the base using the guide hole of the die and the guide column of the base to position it. Rotate the clamping arm inward to make the die and the base interlock automatically, and then pass the electromagnetic die through the coil to make the die press the base. The magnetic force of the base attracts the I-shaped iron rod to form a closed loop to release electric sparks, and complete the magnetic induction sensitivity test of the magnetic induction switch; Explosive shaping: Explosives are placed in the center hole of the base, the semi-finished product is fixed between the die and the base to press the flange edge, and then the coil is energized to magnetize the die to press the base. At the same time, the magnetic induction switch discharges and detonates the explosives, so that the inner surface material of the semi-finished product is instantly heated and high-pressured to ultra-fine the grains, and the inner surface shrinks to offset the deformation strengthening and solution treatment rebound; Pressure-maintaining unloading: The coil is continuously energized, and the die and the base seal the semi-finished product and the heat energy of the explosion, allowing the semi-finished product to cool naturally under the hot, high-pressure and shape-maintaining state. The holding arm is rotated outward to raise the die and separate the semi-finished product from the base.

7. The method according to claim 6, characterized in that The magnetic induction test method of the magnetic induction switch is as follows: a small amount of low-ignition-point explosive is placed between the base and the I-shaped iron rod, the coil current is gradually increased to close the magnetic induction switch to discharge and ignite the explosive, smoke is observed to be discharged from the exhaust hole of the die, and the extreme current passed through the coil when the explosive is ignited is recorded.

8. The method according to claim 6, characterized in that A lead sheet block is placed in the rectangular avoidance groove on the top surface of the die, and the thickness of the lead sheet block matches the distance between the rectangular boss of the clamping arm and the bottom surface of the rectangular avoidance groove.

9. The method according to claim 6, characterized in that A small amount of low-ignition-point explosive is placed in the middle of the center hole of the base, and a high-ignition-point strong explosive is placed in the U-shaped groove of the center hole of the base; before the explosive is detonated, a changing current that is significantly lower than the detonation limit of the explosive is first passed through the coil, so that the coil generates a changing magnetic field to preheat the aerodynamic skin semi-finished product; when the explosive is detonated, a current that is significantly greater than the ignition limit of the explosive is passed through the coil.

10. The method according to claim 9, characterized in that The calculation method of the amount of high explosive is: M = 850*K*V÷Q, 1≤k≤2; Among them, M is the mass of the explosive, in kilograms; V is the volume of the die, in cubic meters; Q is the calorific value of the unit weight of the explosive; K is a coefficient related to the wall thickness, surface area, and shape of the part.

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