A servo-damper device and method for rubber bladder hydroforming

Abstract

The application discloses a kind of rubber bladder hydraulic forming follow-up damping device and method, it is related to rubber bladder forming technical field, including follow-up damping device, rubber bladder forming mechanism and deep learning coordination control system, deep learning coordination control system is connected with follow-up damping device and rubber bladder forming mechanism, rubber bladder forming mechanism is set in the upper portion of follow-up damping device, follow-up damping device is set in the upper portion of upper top cylinder.The application adopts the above structure a kind of rubber bladder hydraulic forming follow-up damping device and method, rubber bladder hydraulic forming follow-up damping device is designed, the device is controlled to realize the dynamic coordination control of " bladder pressure-punch displacement " in starting liquid filling pressurization stage by deep learning coordination control system, ensure that plate is always in stable deformation state in deformation process, to suppress the problem of plate flange area buckling in the process that rubber bladder is completely laid on the surface of plate, i.e. liquid filling pressurization stage.

Description

Technical Field

[0001] This invention relates to the field of rubber bladder forming technology, and in particular to a follow-up damping device and method for hydraulic forming of rubber bladders. Background Technology

[0002] In the aircraft manufacturing industry, sheet metal parts play a crucial role in various aircraft structures. Statistics show that sheet metal parts account for over 50% of all structural components in aircraft. With the rapid development of the aviation industry, the world is gradually phasing out second-generation aircraft, while China's aviation industry is also developing rapidly. The assembly precision requirements for aircraft are increasing, leading to a greater demand for high-quality sheet metal parts. To meet aerodynamic requirements, the design of aerospace sheet metal parts often features large-area rotational characteristics or complex three-dimensional spatial structures composed of intersecting curves. These shapes pose a significant challenge to sheet metal forming processes, requiring deep drawing and large deformation of the sheet metal blank to achieve the required shape. Therefore, the level of sheet metal forming technology often imposes significant constraints on the design. From a forming process perspective, two forming process approaches can currently be used to solve the forming difficulties of these parts: one is the rigid mold forming process; however, this approach requires a huge investment in equipment and mold costs, making it unsuitable for aerospace manufacturing with small production volumes of parts of the same specification and model. The second approach is the flexible soft mold forming process, which relies on soft mold forming technology. Soft die forming technology refers to a technique that uses a fluid medium as a force transmission medium to apply pressure to metal sheets to achieve plastic deformation. It belongs to the category of flexible sheet metal forming technology. Compared with traditional stamping technology, flexible media can replace punches or dies to apply deformation loads to sheet metal, which not only saves mold costs but also has the advantages of flexible loading and strong applicability to workpiece shapes. Therefore, flexible soft die forming processes are now widely used in the manufacturing of aerospace sheet metal parts. Depending on the choice of flexible medium, flexible soft die forming processes mainly include hydraulic forming, viscous medium forming, solid particle medium forming, and rubber bladder forming. Among them, rubber bladder forming is a process that uses hydraulic pressure as a load source and rubber as a force transmission medium. The liquid is wrapped in rubber to form a pressure vessel, and then deformation loads are applied to the sheet metal to complete the plastic forming. Compared with the other three processes, rubber bladder forming has the advantages of being able to flexibly adapt to workpieces of various shapes and sizes; uniform pressure distribution, which can effectively avoid shape deviations and stress concentration problems; precise control of the force and speed during the forming process to meet the forming requirements of different workpieces; high surface quality of the formed parts; lower cost; and environmental friendliness. Therefore, rubber bladder forming is very suitable for the production of personalized and small-batch metal sheet parts. Existing rubber bladder hydroforming processes, when applied to deep-drawn components, exhibit issues such as sinking of the suspended area of ​​the sheet metal and warping of the flange area during the initial filling and pressurization stage. This leads to wrinkling defects in the suspended area of ​​the sheet metal during subsequent deep drawing, affecting the forming quality and production efficiency of the deep-drawn components. To address these problems, this invention proposes a follow-up damping device for rubber bladder hydroforming. Summary of the Invention

[0003] The purpose of this invention is to provide a follow-up damping device and method for rubber bladder hydroforming. This device achieves dynamic coordinated control of "bladder pressure-punch displacement" through a deep neural network control system trained based on a large amount of simulation and experimental data, solving the problem of warping and wrinkling in the flange area of ​​the sheet metal during the initial filling and pressurization stage. This improves the forming quality of deep-drawn components and reduces production costs, supporting the widespread application of rubber bladder hydroforming technology.

[0004] To achieve the above objectives, the present invention provides a follow-up damping device for hydraulic forming of a rubber bladder, comprising a follow-up damping device, a rubber bladder forming mechanism, and a deep learning coordination control system. The deep learning coordination control system is connected to the follow-up damping device and the rubber bladder forming mechanism. The rubber bladder forming mechanism is disposed on the upper part of the follow-up damping device, and the follow-up damping device is disposed on the upper part of the upper cylinder.

[0005] The follow-up damping device includes a follow-up damping hydraulic control system, a damping cylinder, and a replaceable punch. The replaceable punch is connected to the damping cylinder by screws. A piston rod is installed in the damping cylinder and is connected to a spring. The spring and the piston rod are fixed in the damping cylinder by a damping cylinder cover. The piston rod is connected to the follow-up damping hydraulic control system.

[0006] Preferably, the damping cylinder is connected to the lower mold, and the lower end of the lower mold is provided with a sliding mechanism.

[0007] Preferably, the rubber bladder forming mechanism includes an internal hydraulic control system, a rubber bladder, and an oil chamber. The oil chamber is disposed in the upper mold and is connected to the rubber bladder via a clamping ring. The upper end of the oil chamber is connected to the internal hydraulic control system.

[0008] Preferably, the in-bladder hydraulic control system includes a large-displacement hydraulic pump and a proportional relief valve; the follow-up damping hydraulic control system includes a small-displacement hydraulic pump and a high-precision proportional relief valve.

[0009] A method for using a follower damping device in the hydroforming of a rubber bladder includes the following steps:

[0010] S1. Install a follower damping device on the outside of the hydraulic forming machine and install the follower damping device on the hydraulic press;

[0011] S2. Place the plate, and the follow-up damping hydraulic control system controls the piston rod to move downward and press against the upper cylinder. The damping cylinder body drives the replaceable punch to extend pre-extend.

[0012] S3, the internal hydraulic control system controls a large-displacement hydraulic pump to fill the rubber bladder with liquid and pressurize it until the rubber bladder contacts the plate at a certain pressure.

[0013] S4. During the process of establishing the pressing relationship on the upper surface of the plate, the deep learning system coordinates and controls the changes in pressure inside the bladder and the damping cylinder.

[0014] S5. The edge-pressing relationship is established on the upper surface of the plate, and the follow-up damping gradually returns to zero, completing the liquid filling and pressurization stage.

[0015] Preferably, in S1, the follower damping device is installed on the hydraulic press working platform by a transverse hydraulic push device, and the damping cylinder body is coaxially set with the upper cylinder.

[0016] Preferably, in S2, the deep learning coordination control system calculates the pre-extension displacement of the replaceable punch by using the material parameters of the plate and the workpiece parameters of the target part.

[0017] Preferably, the deep learning coordinated control system in S4 calculates the appropriate intracavitary pressure-pump displacement relationship at each moment and outputs proportional current to coordinate control the proportional relief valve and the high-precision proportional relief valve.

[0018] Therefore, the following beneficial effects are achieved by the present invention, which employs the above-described structure for a follower-up damping device and method for hydroforming a rubber bladder:

[0019] (1) The present invention designs a follow-up damping device for rubber bladder hydraulic forming. The device achieves dynamic coordination control of "bladder pressure-punch displacement" in the initial filling and pressurization stage through deep learning coordination control system, ensuring that the plate is always in a stable deformation state during the deformation process, thereby suppressing the problem of warping and wrinkling of the plate flange area during the process of the rubber bladder being completely flat on the plate surface, i.e. the filling and pressurization stage.

[0020] (2) In this invention, the follow-up damping device adopts a hydraulic cylinder design. The follow-up damping hydraulic control system controls the lifting of the damping cylinder to achieve the lifting of the punch. The cylinder lifting method can ensure the completion of the target function while also having the advantages of convenient installation and smooth working action.

[0021] (3) This invention proposes a damping dynamic control strategy. This strategy uses a deep learning algorithm as the core algorithm of the control system. It can have self-learning ability based on fully utilizing existing simulation and experimental data to summarize the deformation law of the plate. When different materials are used for forming, only basic material parameters such as mechanical property parameters, workpiece parameters such as geometric dimensions and process parameters such as lubrication method need to be given. The system can automatically give a suitable initial position to reduce the experimental time cost in the early stage.

[0022] (4) The present invention adopts a damping design integrated into the punch structure, which can effectively avoid the problem of low control accuracy of the hydraulic press top cylinder under small pressure and short stroke under the premise of low equipment cost.

[0023] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the follower damping device for hydroforming a rubber bladder according to the present invention;

[0025] Figure 2 This is an assembly diagram of the follower damping device of the present invention;

[0026] Figure 3 This is a schematic diagram of the installation structure of the follower damping device of the present invention;

[0027] Figure 4 This is a schematic diagram of the replaceable punch pre-extend structure of the present invention;

[0028] Figure 5 This is a schematic diagram showing the initiation of fluid filling and pressurization of the rubber bladder of the present invention;

[0029] Figure 6 This is a schematic diagram of the damping cylinder returning to zero position according to the present invention;

[0030] Figure Labels

[0031] 1. Oil chamber; 2. Rubber bladder; 3. Pressure ring; 4. Upper mold; 5. Sheet metal; 6. Replaceable punch; 7. Damping cylinder body; 8. Piston rod; 9. Spring; 10. Damping cylinder head; 11. Lower mold; 12. Sliding mechanism; 13. Upper cylinder; 14. Hydraulic press; 15. In-bladder hydraulic control system; 16. Deep learning coordination control system; 17. Follow-up damping hydraulic control system; 18. Proportional relief valve; 19. Large displacement hydraulic pump; 20. High-precision proportional relief valve; 21. Small displacement hydraulic pump; 22. Screw. Detailed Implementation

[0032] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0033] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0034] Example

[0035] Please see Figure 1-6 The present invention provides a follow-up damping device for hydraulic forming of a rubber bladder, including a follow-up damping device, a rubber bladder forming mechanism and a deep learning coordination control system. The deep learning coordination control system is connected to the follow-up damping device and the rubber bladder forming mechanism. The rubber bladder forming mechanism is disposed on the upper part of the follow-up damping device, and the follow-up damping device is disposed on the upper part of the upper cylinder 13.

[0036] The follow-up damping device includes a follow-up damping hydraulic control system 17, a damping cylinder 7, and a replaceable punch 6. The replaceable punch 6 is connected to the damping cylinder 7 by screws 22. A piston rod 8 is installed inside the damping cylinder 7 and is connected to a spring 9. The lower end of the piston rod 8 is connected to the spring 9, and the upper end of the piston rod 8 is a rodless cavity. The spring 9 and the piston rod 8 are fixed inside the damping cylinder 7 by a damping cylinder cover 10. Both the damping cylinder 7 and the replaceable punch 6 are mounted on a lower die 11. A sliding mechanism 12 is provided at the lower end of the lower die 11. The sliding mechanism 12 is mounted on the lower die 11 by screws and is also mounted on a hydraulic press 14 for easy installation. The piston rod 8 is connected to the follow-up damping hydraulic control system 17, which controls the movement of the piston rod 8 to extend and retract the replaceable punch 6. The servo damping hydraulic control system 17 includes a small-displacement hydraulic pump 21 and a high-precision proportional relief valve 20, which controls the falling process of the damping cylinder 7. The servo damping hydraulic control system 17 receives signals from the deep learning coordinated control system 16 to adjust the damping cylinder 7.

[0037] The rubber bladder forming mechanism includes an internal hydraulic control system 15, a rubber bladder 2, and an oil chamber 1. The oil chamber 1 is located inside the upper mold 4 and is connected to the rubber bladder 2 via a clamping ring 3. Hydraulic oil is injected into the rubber bladder 2 to pressurize the sheet metal and prevent warping and wrinkling in the flange area of ​​the sheet metal. The upper end of the oil chamber 1 is connected to the internal hydraulic control system 15. The internal hydraulic control system 15 includes a high-displacement hydraulic pump 19 and a proportional relief valve 18.

[0038] A method of using a follow-up damping device for hydroforming a rubber bladder includes the following steps:

[0039] S1. Assemble a follower damping device outside the hydraulic forming machine. After sleeve the spring 9 on the piston rod 8, place the entire assembly into the damping cylinder 7 and secure it with the damping cylinder cover 10. Then, connect the replaceable punch 6 to the damping cylinder 7 using screws 22 and install the entire assembly into the lower mold 11. The lower mold 11 is pre-installed with a sliding mechanism 12 to ensure subsequent installation on the working platform of the rubber bladder hydraulic forming machine. See the schematic diagram of the follower damping device assembly. Figure 2 The follow-up damping device is installed on the hydraulic press 14 and placed on the slide rail of the working platform of the hydraulic press 14. Then, the follow-up damping device is pushed onto the working platform of the hydraulic press 14 by the transverse hydraulic push device, ensuring that the damping cylinder 7 and the upper cylinder 13 are coaxially set. The follow-up damping device is connected to the follow-up damping hydraulic control system 17 through a hose.

[0040] S2. Place the sheet metal, and pre-extend the replaceable punch 6. After placing the sheet metal 5 on the lower mold 11, the upper mold 4 moves down and closes with the lower mold 11 to form a sealed cavity. Input the material parameters of the sheet metal 5, the workpiece parameters of the target part, and process parameters such as lubrication into the deep learning coordination control system 16. The deep learning coordination control system 16 calculates the pre-extend displacement of the replaceable punch 6 and sends it to the follow-up damping hydraulic control system 17. The follow-up damping hydraulic control system 17 controls the small displacement hydraulic pump 21 to work. The piston rod 8 moves downward and stops moving after hitting the upper cylinder 13. The damping cylinder 7 drives the replaceable punch 6 to the pre-extend position.

[0041] S3. The rubber bladder begins to be filled with liquid and pressurized, and then contacts the plate. The hydraulic control system 15 inside the bladder controls the large-displacement hydraulic pump 19 to fill the rubber bladder 2 with hydraulic oil through the oil chamber 1. The rubber bladder 2 is gradually expanded by the action of the oil. When it is expanded to a certain extent, it contacts the plate 5 and exerts a certain pressure on the plate 5. The plate 5 dissipates the pressure through the damping device to ensure that it does not deform.

[0042] S4. The system coordinates and controls the follow-up damping to gradually return to zero. After the rubber bladder 2 contacts the plate 5, the deep learning coordination control system 16 calculates the appropriate pressure-pump displacement relationship at each moment and outputs a proportional current to coordinate and control the proportional relief valve 18 and the high-precision proportional relief valve 20. This changes the balance between the pressure inside the bladder and the pressure inside the damping cylinder, realizing the dynamic change of the damping cylinder 7 during the filling and pressurization stage. This ensures that the plate 5 does not deform before the pressing relationship is fully established on the upper surface. As the pressing relationship is fully established on the upper surface of the plate 5, the damping cylinder 7 gradually returns to zero, completing the filling and pressurization stage.

[0043] Therefore, this invention adopts a follow-up damping device and method for rubber bladder hydroforming with the above-mentioned structure. This invention designs a follow-up damping device for rubber bladder hydroforming. This device uses a deep learning coordinated control system to achieve dynamic coordinated control of "bladder pressure - punch displacement" during the initial filling and pressurization stage, ensuring that the sheet metal remains in a stable deformation state throughout the deformation process. This suppresses the problem of warping and wrinkling in the flange area of ​​the sheet metal during the filling and pressurization stage when the rubber bladder is completely flattened on the sheet metal surface. In this invention, the follow-up damping device uses a hydraulic cylinder design. The follow-up damping hydraulic control system controls the lifting of the damping cylinder to lift the punch. This cylinder lifting method ensures the completion of the target function while also offering advantages such as convenient installation and smooth feed action. This invention proposes a damping dynamic control strategy. This strategy uses a deep learning algorithm as the core algorithm of the control system. Based on fully utilizing existing simulation and experimental data to summarize the deformation law of the sheet metal, it possesses self-learning capabilities. When using different materials for forming, only material parameters such as mechanical property parameters, workpiece parameters such as geometric dimensions, and process parameters such as lubrication method need to be provided. The system can automatically provide a suitable initial position to reduce the initial experimental time cost. This invention employs a damping design integrated into the punch structure, which can effectively avoid the problem of low control accuracy of the hydraulic press's top cylinder under low pressure and short stroke while maintaining low equipment cost.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method of using a follower damping device for hydroforming a rubber bladder, characterized in that, The device includes a follow-up damping device, a rubber bladder forming mechanism, and a deep learning coordination control system. The deep learning coordination control system is connected to the follow-up damping device and the rubber bladder forming mechanism. The rubber bladder forming mechanism is located on the upper part of the follow-up damping device, and the follow-up damping device is located on the upper part of the upper cylinder. The follow-up damping device includes a follow-up damping hydraulic control system, a damping cylinder, and a replaceable punch. The replaceable punch is connected to the damping cylinder by screws. A piston rod is installed in the damping cylinder and is connected to a spring. The spring and the piston rod are fixed in the damping cylinder by a damping cylinder cover. The piston rod is connected to the follow-up damping hydraulic control system. The method of use includes the following steps: S1. Install a follower damping device on the outside of the hydraulic forming machine and install the follower damping device on the hydraulic press; S2. Place the plate, and the follow-up damping hydraulic control system controls the piston rod to move downward and press against the upper cylinder. The damping cylinder body drives the replaceable punch to extend pre-extend. S3, the internal hydraulic control system controls a large-displacement hydraulic pump to fill the rubber bladder with liquid and pressurize it until the rubber bladder contacts the plate at a certain pressure. S4. During the process of establishing the pressing relationship on the upper surface of the plate, the deep learning coordination control system coordinates and controls the changes in pressure inside the bladder and the pressure inside the damping cylinder. S5. The edge-pressing relationship is established on the upper surface of the plate, and the follow-up damping gradually returns to zero, completing the liquid filling and pressurization stage.

2. The method of using the follow-up damping device for hydroforming a rubber bladder according to claim 1, characterized in that: The damping cylinder is connected to the lower mold, and a sliding mechanism is provided at the lower end of the lower mold.

3. The method of using the follow-up damping device for hydroforming a rubber bladder according to claim 2, characterized in that: The rubber bladder forming mechanism includes an internal hydraulic control system, a rubber bladder, and an oil chamber. The oil chamber is located inside the upper mold and is connected to the rubber bladder via a clamping ring. The upper end of the oil chamber is connected to the internal hydraulic control system.

4. The method of using the follow-up damping device for hydroforming a rubber bladder according to claim 3, characterized in that: The in-bladder hydraulic control system includes a large-displacement hydraulic pump and a proportional relief valve; the follow-up damping hydraulic control system includes a small-displacement hydraulic pump and a high-precision proportional relief valve.

5. The method of using the follow-up damping device for rubber bladder hydroforming according to claim 4, characterized in that: In S1, the follow-up damping device is installed on the hydraulic press working platform through a transverse hydraulic push device, and the damping cylinder body is set coaxially with the upper cylinder.

6. The method of using the follow-up damping device for hydroforming a rubber bladder according to claim 5, characterized in that: In S2, the deep learning-based coordinated control system calculates the pre-extension displacement of the replaceable punch based on the material parameters of the sheet metal and the workpiece parameters of the target part.

7. The method of using the follow-up damping device for rubber bladder hydroforming according to claim 6, characterized in that: The deep learning-based coordinated control system in S4 calculates the appropriate intrabladder pressure-pump displacement relationship at each moment and outputs proportional current to coordinate the control of the proportional relief valve and the high-precision proportional relief valve.

Images