Aircraft tail shaft thin-walled aluminum alloy pipe bending and straightening device and method

Abstract

The application provides a thin-wall aluminum alloy pipe bending and straightening device and method for an aviation tail shaft. A double-mode power boosting system in the device comprises a pedal boosting adjusting device and a fine boosting adjusting device; a sliding frame is provided with an upper belt on the front face and connected with the pedal boosting adjusting device and the fine boosting adjusting device through chains on the back face; after the pipe passes through a first lower belt, the upper belt and a second lower belt in sequence, the pipe is pressed by the pedal boosting adjusting device and the fine boosting adjusting device respectively; the chains connected with the pedal boosting adjusting device and the fine boosting adjusting device drive the upper belt to move upward, the fulcrum of the upper belt is a force point, the fulcrums of the first lower belt and the second lower belt are support points, the three form a reverse action of symmetrical distribution force, and finally the thin-wall aluminum alloy pipe bending and straightening work is completed; by the application, the pipe damage can be reduced, the straightening precision can be ensured, the pipe can meet the high-precision size and shape tolerance, and the assembly or use precision requirement can be met.

Description

Technical Field

[0001] This invention belongs to the field of thin-walled high-precision aluminum alloy tube straightening technology, and particularly relates to a bending and straightening device and method for thin-walled aluminum alloy tubes used in aircraft tail shafts. Background Technology

[0002] In modern industry, thin-walled high-precision aluminum alloy tubing, with its lightweight, high strength, and excellent corrosion resistance, has been widely used in many key industries such as aerospace, rail transportation, and high-end equipment manufacturing. However, with the rapid development of these industries, increasingly stringent requirements have been placed on the precision and quality standards of thin-walled high-precision aluminum alloy tubing. The straightness of the tubing, as one of the key indicators of its quality, directly affects its performance during subsequent processing and use. Even minor bending defects can lead to problems with tight fit during assembly, thus affecting the stability and reliability of the entire system. For example, in the manufacturing of aero-engines, if the straightness of the aluminum alloy tubing does not meet the requirements, it may cause poor airflow inside the engine, reducing engine efficiency. Secondly, excessive straightness can make it difficult for the tubing to precisely align with other components of the tail shaft system during assembly, potentially requiring forced assembly. Over time, stress concentration areas are prone to fatigue damage, reducing the overall structural reliability and even causing eccentric vibrations that can be transmitted to the fuselage, affecting the stable operation of aviation equipment, causing resonance, and leading to serious safety accidents.

[0003] Currently, to ensure the straightness of thin-walled high-precision aluminum alloy tubing used in tail shafts, the primary method is traditional roller straightening. Roller straightening involves applying pressure to the tubing using multiple sets of straightening rollers, causing the tubing to bend repeatedly between the rollers, thereby gradually eliminating the curvature. However, due to the thin walls of the thin-walled high-precision aluminum alloy tubing used in tail shafts, the roller straightening rollers are in direct contact with the tubing surface during the roller straightening process, generating significant friction and localized pressure concentration. This often leads to defects such as scratches and indentations on the tubing surface, severely affecting the surface quality and appearance of the tubing. In the aerospace field, any minute defects on the tubing surface can become stress concentration points, triggering the initiation and propagation of fatigue cracks under long-term alternating loads, reducing the service life and structural safety of the tubing. Secondly, thin-walled aluminum alloy tubing has poor rigidity, making it susceptible to uneven deformation due to external forces during straightening. Traditional roller straightening methods struggle to precisely control the deformation of different parts of the tubing, making it difficult to achieve ideal straightening accuracy for thin-walled aluminum alloy tubing with high precision requirements. Summary of the Invention

[0004] This invention provides a bending and straightening device and method for thin-walled aluminum alloy tubing used in aircraft tail shafts. It solves the problems in existing technologies where, due to high precision requirements for the tubing but large outer diameter and thin wall thickness, uneven straightening, deterioration of tubing roundness after straightening, and irreversible defects such as pitting on the outer surface occur during the finished product stage. This invention reduces tubing damage and ensures straightening accuracy. Precise straightening ensures that the tubing meets high-precision dimensional and shape tolerances, satisfying the precision requirements of subsequent assembly or use. It is fast and stable, reduces rework, and improves the finished product qualification rate. It also avoids excessive damage to the tubing during straightening, preventing cracks, wrinkles, or performance degradation, and preserving the original material properties. The technical solution is as follows: In a first aspect, a bending and straightening device for thin-walled aluminum alloy tubing used in aircraft tail shafts is provided, comprising a vehicle body 1, a sliding frame 2, an upper strap 3, a first lower strap, a second lower strap, a support adjustment seat 5, a chain 8, and a dual-mode power boosting system. The dual-mode power boosting system includes a foot-operated boost adjustment device 9 and a fine boost adjustment device 10. The front of the vehicle body 1 fits into the sliding frame 2. The upper strap 3 is installed on the front of the sliding frame 2, and the back of the sliding frame 2 is connected to the foot-operated boost adjustment device 9 and the fine boost adjustment device 10 via the chain 8. The first lower strap and the second lower strap are connected to the support adjustment seat 5. After the pipe passes through the first lower strap, the upper strap 3, and the second lower strap in sequence, pressure is applied by the foot pedal pressure adjustment device 9 and the fine pressure adjustment device 10 respectively. The chain 8 connected to the foot pedal pressure adjustment device 9 and the fine pressure adjustment device 10 drives the upper strap 3 to move upward. At this time, the first lower strap, the upper strap 3, and the second lower strap form three fulcrums, which are arranged linearly. The fulcrum where the upper strap 3 is located is the force application point, and the fulcrum where the first lower strap and the second lower strap are located is the support point. The three form a symmetrical distribution of opposing forces, which finally completes the bending and straightening work of the thin-walled aluminum alloy pipe.

[0005] Among them, the upper strap 3, the first lower strap and the second lower strap are deformable straps. The upper strap 3 and the lower strap act on the pipe and adhere to the surface of the pipe through their own deformability when the pipe is in relative motion.

[0006] The upper and lower straps, due to their flexible nature, can adhere to the pipe surface through their deformability when applied to the pipe, achieving both stable binding and avoiding damage such as squeezing and scratching that can be caused by rigid contact, thus perfectly protecting the pipe surface and structure.

[0007] The support adjustment seat 5 includes a lower strap fixing frame 15 connected to the lower strap, and the side of the support adjustment seat 5 is provided with an adjustment slider 13 that can adjust the spacing by means of a limiting screw 14.

[0008] The support adjustment seat can fix the lower strap on one hand, and the adjustment slider 13 set on the side can adjust its spacing through the limit screw 14 to meet the placement requirements of thin-walled aluminum alloy tubes of different diameters.

[0009] The adjusting slider 13 has a built-in rubber roller 11 that provides flexible support and straightening adaptation for different axial positions of the pipe. The rubber roller 11 is fixed in the adjusting slider 13 by the roller fixing rod 12.

[0010] By driving the rubber roller 11, flexible support and straightening adaptation of the pipe at different axial positions are achieved. The elastic contact characteristics of the rubber roller 11 can accurately match the pipe to be straightened part with the displacement of the adjusting slider 13, and can avoid rigid friction with the pipe surface through the buffer damping effect of the material itself. Thus, while ensuring the flexibility of the straightening position adjustment, the surface quality of the pipe can be effectively protected.

[0011] A lead screw 16 is installed below the lower strap fixing bracket 15. One end of the lead screw 16 has a positive thread, and the other end has a negative thread. When the motor 17 drives the lead screw 16 to rotate, the lower strap fixing bracket 15, which cooperates with the lead screw 16, will move symmetrically left and right on the lead screw 16 with the upper strap 3 as the center due to the difference in the direction of the thread, thereby adjusting the distance between the two lower strap fixing brackets 15. In this way, not only are the two force support points in the pipe straightening area made to form a perpendicular, symmetrical, and stable force relationship with the upper strap, but it can also be adapted to the straightening of pipes of different lengths.

[0012] Among them, the output shaft gear of motor 17 meshes with the end gear of lead screw 16 to form a meshing transmission pair 22. When motor 17 starts, the rotational force is transmitted without impact through meshing transmission pair 22, driving lead screw 16 to rotate in straightening gap adjustment groove 6, reducing energy loss and mechanical vibration in the transmission process, and improving the stability and accuracy of lead screw movement.

[0013] The dual-mode power boosting system (foot-operated boosting adjustment device 9 and fine boosting adjustment device 10) is connected to the vehicle body 1 and the chain 8. These two systems integrate a foot-operated linkage boosting mechanism and a manual precision boosting mechanism. When triggered by the foot pedal, rapid energy storage and boosting are achieved through a mechanical linkage structure, adapting to the high-efficiency output during the coarse adjustment stage of the pipe. During manual adjustment, a fine transmission component completes the incremental force value, meeting the millimeter-level precision control requirements of the straightening and finishing stage. The two modes can be switched as needed, achieving flexible power output adaptation and, through a collaborative design involving human-machine interaction, ensuring both efficiency and precision in the pipe straightening process.

[0014] The vehicle body 1 is equipped with a dial indicator sliding frame 19, on which a dial indicator 18 is fixed. The dial indicator 18 is embedded in the dial indicator sliding frame 19, and the dial indicator 18 is fixed to the sliding frame 19 to form a stable detection benchmark. When the hydraulic system completes the pressurization and drives the force feedback platform 20 to contact the probe of the dial indicator 18, the high-precision displacement sensing characteristics of the dial indicator 18, combined with the straightness measuring machine, convert the deformation of the pipe under stress due to local bending into a quantifiable value of force, thereby realizing the feedback and precise control of the force-shape coordination relationship during the straightening process of local bending of the pipe.

[0015] Secondly, a method for a bending and straightening device for thin-walled aluminum alloy tubing used in aircraft tail shafts is provided, comprising the following steps: Step 1: Inspect the pipe curvature; confirm the straightening position and displacement by measuring the straightness. Step 2: Clamping and positioning: Adjust the limiting screw 14 on the support adjustment seat 5 according to the outer diameter of the pipe, adjust the distance between the two sets of adjustment sliders 13 on one side to the preset value, pass the pipe through the first lower strap, the upper strap 3, and the second lower strap in sequence, and place it stably on the rubber roller 11 of the adjustment slider 13 in the support adjustment seat 5; at this time, monitor the straightening position, start the motor 17, and the meshing transmission pair 22 formed by the motor 17 and the lead screw 16 drives the lead screw 16 to start rotating in the straightening gap adjustment groove 6. Through the thread characteristics of the lead screw 16 itself, the support adjustment seat 5 starts to reciprocate, and the lower strap fixing bracket 15 drives the lower strap to move. When the lower strap reaches the preset position, turn off the motor; Step 3: Perform flexible straightening: Use the foot-operated pressure booster 9 for rapid pressure boosting, the cylinder moves upward, the chain 8 moves circumferentially, the sliding frame 2 moves upward, driving the upper strap 3 upward. At this time, the first and second lower straps bind the pipe. Then, the force feedback platform 20 contacts the dial indicator 18 probe in the gauge sliding frame 19. When the difference is the preset value, the fine adjustment device 10 is activated to make a small adjustment to reach the preset displacement value. The pressure is held for the preset time, and then the pressure is slowly released to achieve the bending straightening of the thin-walled pipe. Step 4: Check the curvature: Remove the thin-walled aluminum alloy tube and check the curvature again until it meets the requirements.

[0016] The beneficial effects of this invention are at least as follows: 1) Unlike traditional thin-walled high-precision aluminum alloy tube straightening devices that rely on fixed molds, the device of this invention achieves rapid adaptation to thin-walled tubes of different diameters (covering a wide range of diameters) and different degrees of curvature through modular adjustment components (such as sliding support adjustment seats, deformable straps, adaptive rubber roller adjustment support structures, etc.), solving the problem of poor versatility of traditional devices that use "one tube, one device", and significantly improving structural flexibility.

[0017] 2) By combining the flexible support structure with built-in rubber rollers and deformable straps, the buffering properties of the material are utilized to avoid damage such as scratches and indentations on the surface of thin-walled pipes caused by traditional rigid supports. At the same time, it reduces secondary deformation of the pipes (such as local dents and wrinkles) caused by rigid contact during the straightening process, thus solving the common industry problem of "easy deformation during straightening" and "easy surface damage" of thin-walled pipes.

[0018] 3) With the help of the multi-dimensional displacement adjustment of the slider and the real-time feedback of the dial gauge, directional force and precision control can be applied to any local bending part of the pipe (such as asymmetrical bending). This overcomes the shortcomings of traditional devices that are effective in straightening the overall bending but lack the ability to finely clean the corners of local areas, and achieves the dual straightening effect of "full coverage + local precision".

[0019] 4) It reduces the reliance on specialized customized equipment. Core components can be made through processing, reducing manufacturing costs by more than 30% compared to similar specialized equipment. At the same time, due to the increased versatility, it reduces the time cost of equipment replacement in the production of multi-specification pipes, and increases production efficiency by more than 40%. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the front structure of the device of the present invention; Figure 2 This is a schematic diagram of the rear structure of the device of the present invention; Figure 3 for Figure 1 Enlarged schematic diagram of the structure of region A in the middle; Figure 4 for Figure 1 Enlarged schematic diagram of the structure of region B in the middle; Figure 5 for Figure 2 Enlarged schematic diagram of the structure in region C.

[0022] Explanation of reference numerals in the attached figures: 1—Car body, 2—Sliding frame, 3—Upper belt, 4—Lower belt, 5—Support adjustment seat, 6—Straightening gap adjustment groove, 8—Chain, 9—Foot pedal pressure adjustment device, 10—Fine pressure adjustment device, 11—Rubber roller, 12—Roller fixing rod, 13—Adjusting slider, 14—Limit screw, 15—Lower belt fixing frame, 16—Lead screw, 17—Motor, 18—Dial indicator, 19—Indicator head sliding frame, 20—Force feedback platform, 21—Protective net, 22—Meshing transmission pair. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] The features and illustrative embodiments of various aspects of the present invention will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention. The invention is by no means limited to any specific setups and methods set forth below, but covers any improvements, substitutions, and modifications to structures, methods, and devices without departing from the spirit of the invention. Well-known structures and techniques are not shown in the drawings and the following description to avoid unnecessarily obscuring the invention.

[0025] One embodiment of the present invention provides a bending and straightening device for thin-walled aluminum alloy tubing used in aircraft tail shafts, see [link to relevant documentation]. Figure 1 and Figure 2 , Figure 5 The device includes: a vehicle body 1, a sliding frame 2, an upper strap 3, a first lower strap 4, a second lower strap 4, a support adjustment seat 5, an adjustment slider 13, a chain 8, a foot pedal pressure adjustment device 9, a fine pressure adjustment device 10, a dial indicator 18, an indicator head sliding frame 19, a force feedback platform 20, and a protective net 21. The vehicle body 1 is placed stably, with its front side fitting into the sliding frame 2. The upper strap 3 is installed on the front of the sliding frame 2, and its back side is connected to the foot pedal pressure adjustment device 9 and the fine pressure adjustment device 10 via a chain 8. The protective net 21 is fixed to the vehicle body 1. The pipe passes through the first lower strap 4, the upper strap 3, and the second lower strap 4 in sequence, and is placed on the adjustment slider 13 in the support adjustment seat 5. The foot pedal pressure adjustment device 9 is used to quickly increase the pressure, the cylinder moves upward, the chain 8 moves circumferentially, and the sliding frame 2 moves upward, driving the upper strap 3 upward. At this time, the first lower strap 4 and the second lower strap 4 fixed on the lower strap fixing frame 15 bind the pipe. Then, the force feedback platform 20 contacts the probe of the dial indicator 18 in the instrument head sliding frame 19. When the difference is 0.5mm, the fine pressure adjustment device 10 is activated to make a slight adjustment to achieve the required displacement value, thereby realizing the bending and straightening of the thin-walled pipe.

[0026] In this embodiment, see Figure 3 Two sets of rubber rollers 11 are respectively inserted and fixed to the adjusting slider 13 via roller fixing rods 12. The adjusting slider 13 is adapted to the slide groove to form a sliding pair. With the help of the limiting screw 14 at the bottom of the adjusting slide groove, the adjusting slider 13 can be driven to achieve precise displacement adjustment along the slide groove, thereby meeting the support adaptation requirements of pipes of different diameters during straightening operations and ensuring the stability and compatibility of support positioning during the straightening process.

[0027] In this embodiment, see Figure 4 The output shaft gear of motor 17 and the end gear of lead screw 16 form a specific matching meshing transmission pair 22. One end of lead screw 16 adopts a positive thread and the other end adopts a negative thread. The rotational force of motor 17 when it starts is transmitted without impact through gear pair 22, driving lead screw 16 to move precisely in straightening spacing adjustment groove 6. The lower strap fixing bracket 15 that cooperates with lead screw 16 will move symmetrically left and right on lead screw 16 with the upper strap 3 as the center due to the difference in the direction of the thread, thereby adjusting the distance between the two lower strap fixing brackets 15. In this way, not only are the two force support points in the pipe straightening area vertical, symmetrical and stable force relationship with the upper strap 3, but it can also be adapted to the straightening of pipes of different lengths.

[0028] The usage process of the device provided in this embodiment of the invention is as follows: First, the pipe is tested for curvature to confirm the correction position and displacement. Next, clamping and positioning are completed for the pipe to be straightened. That is, the limiting screw 14 on the support adjustment seat 5 is adjusted according to the outer diameter of the pipe, and the distance between the two sets of adjustment sliders 13 on one side is adjusted to the corresponding size. The pipe is then passed through the first lower strap 4, the upper strap 3, and the second lower strap 4 in sequence, and placed stably on the rubber roller 11 of the adjustment slider 13 in the support adjustment seat 5 (the rubber roller 11 is fixed in the adjustment slider 13 by the roller fixing rod 12). At this time, the straightening position is observed, and the motor 17 is started. The meshing transmission pair 22 formed by the motor 17 and the lead screw 16 drives the lead screw 16 to start rotating in the straightening gap adjustment groove 6. Through the thread characteristics of the lead screw 16, the support adjustment seat 5 starts to reciprocate. The lower strap fixing frame 15 moves the lower strap 4. When the lower strap 4 reaches the ideal position, the motor is turned off. Finally, flexible straightening is performed as required. Specifically, the worker stands on the back of the vehicle body 1, outside the protective net 21, and uses the foot-operated pressure adjustment device 9 to quickly increase the pressure. The cylinder moves upward, the chain 8 moves circumferentially, and the sliding frame 2 moves upward, driving the upper strap 3 upward. At this time, the first lower strap and the second lower strap 4 restrain the pipe. Then, the force feedback platform 20 contacts the probe of the dial indicator 18 in the instrument head sliding frame 19. When the difference is 0.5mm, the fine adjustment device 10 is activated to make a slight adjustment to reach the required displacement value. The pressure is maintained for 5-15 seconds as required. At this time, the lower straps 4 on both sides and the upper strap 3 in the middle form three fulcrums, which are arranged linearly. The fulcrum where the upper strap 3 is located is the force application point, and the fulcrums where the lower straps 4 on both sides are the support points. The three form a symmetrical distribution of forces with opposite effects. Through local elastic-plastic deformation, the bending and straightening of the thin-walled pipe is achieved.

[0029] The above description merely illustrates embodiments of the present invention and is quite specific and detailed; however, it should not be construed as limiting the scope of the patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Furthermore, any parts of the present invention not described in detail are conventional techniques.

Claims

1. A bending and straightening device for thin-walled aluminum alloy tubing used in aircraft tail shafts, characterized in that, The system includes a vehicle body, a sliding frame, an upper belt, a first lower belt, a second lower belt, a support adjustment seat, a chain, and a dual-mode power boosting system. The dual-mode power boosting system includes a foot pedal boosting adjustment device and a fine boosting adjustment device. The front of the vehicle body fits into the sliding frame. The upper belt is installed on the front of the sliding frame, and the back is connected to the foot pedal boosting adjustment device and the fine boosting adjustment device via a chain. The first lower belt and the second lower belt are connected to the support adjustment seat. After the tube passes through the first lower belt, the upper belt, and the second lower belt in sequence, pressure is applied by the foot pedal boosting adjustment device and the fine boosting adjustment device, respectively. The chain connected to the foot pedal boosting adjustment device and the fine boosting adjustment device drives the upper belt to move upward. At this time, the first lower belt, the upper belt, and the second lower belt form three fulcrums, arranged linearly. The fulcrum where the upper belt is located is the force application point, and the fulcrums where the first lower belt and the second lower belt are located are the support points. The three form a symmetrically distributed force with opposite effects, ultimately completing the bending and straightening work of the thin-walled aluminum alloy tube.

2. The apparatus according to claim 1, characterized in that, The upper strap, the first lower strap, and the second lower strap are deformable straps. When the upper strap and the lower strap act on the pipe and move relative to it, they adhere to the surface of the pipe through their own deformability.

3. The apparatus according to claim 1, characterized in that, The support adjustment seat includes a lower strap fixing frame connected to the lower strap, and the side of the support adjustment seat is provided with an adjustment slider that can adjust the spacing by means of a limiting screw.

4. The apparatus according to claim 3, characterized in that, The adjusting slider has built-in rubber rollers that provide flexible support and straightening adaptation for different axial positions of the pipe. The rubber rollers are fixed in the adjusting slider by roller fixing rods.

5. The apparatus according to claim 3, characterized in that, A lead screw is installed below the lower strap fixing bracket. One end of the lead screw has a positive thread and the other end has a negative thread. When the motor drives the lead screw to rotate, the lower strap fixing bracket that cooperates with the lead screw will move symmetrically left and right on the lead screw with the upper strap as the center due to the difference in the direction of the thread, thereby adjusting the distance between the two lower strap fixing brackets.

6. The apparatus according to claim 5, characterized in that, The output shaft gear of the motor meshes with the end gear of the lead screw to form a meshing transmission pair. When the motor starts, the rotational force is transmitted without impact through the meshing transmission pair, driving the lead screw to rotate in the straightening gap adjustment groove.

7. The apparatus according to claim 5, characterized in that, When triggered by foot pedal, rapid energy storage and pressurization are achieved through a mechanical linkage structure, which is suitable for the high-efficiency output during the coarse adjustment stage of the pipe; when manually adjusted, the fine transmission components complete the micro-amplitude force increment, which meets the millimeter-level precision control during the straightening and finishing stage.

8. The apparatus according to claim 5, characterized in that, The vehicle body is equipped with a dial indicator sliding frame, on which a dial indicator is fixed. When the hydraulic system completes pressurization and drives the force feedback platform to contact the dial indicator probe, the high-precision displacement sensing characteristics of the dial indicator, combined with the straightness measuring machine, convert the deformation of the pipe under stress due to local bending into a quantifiable force value.

9. A method for a bending and straightening device for thin-walled aluminum alloy tubing used in aircraft tail shafts, characterized in that, The steps include the following: Step 1: Inspect the pipe's curvature; Step 2: Clamping and positioning: Adjust the limit screw on the support adjustment seat according to the outer diameter of the pipe, and adjust the distance between the two sets of adjustment sliders on one side to the preset value. Pass the pipe through the first lower strap, the upper strap, and the second lower strap in sequence, and place it stably on the rubber roller of the adjustment slider in the support adjustment seat. At this time, monitor the straightening position, start the motor, and the meshing transmission pair formed by the motor and the lead screw drives the lead screw to start rotating in the straightening distance adjustment groove. Through the thread characteristics of the lead screw itself, the support adjustment seat starts to reciprocate. The lower strap fixing frame drives the lower strap to move. When the lower strap reaches the preset position, turn off the motor. Step 3: Perform flexible straightening: Use a foot-operated pressure booster for rapid pressure boosting, the cylinder moves upward, the chain moves circumferentially, and the sliding frame moves upward, driving the upper belt upward. At this time, the first and second lower belts restrain the pipe. Then, the force feedback platform contacts the dial indicator probe in the sliding frame. When the difference is the preset value, the fine adjustment device is activated for micro-adjustment to reach the preset displacement value. The pressure is held for the preset time, and then the pressure is slowly released to achieve the bending straightening of the thin-walled pipe. Step 4: Check the curvature: Remove the thin-walled aluminum alloy tube and check the curvature again until it meets the requirements.

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