A compact tube plate composite forming hydraulic system and control method

Abstract

The application discloses a compact tube-plate composite forming hydraulic system and a control method, relates to the technical field of metal plastic forming, and relates to a tube-plate composite forming device which comprises a workbench, two groups of hydraulic devices, a liquid conveying device, a numerical control system, and the like.

Description

Technical Field

[0001] This invention relates to the field of metal plastic forming technology, and in particular to a compact tube sheet composite forming hydraulic system and control method. Background Technology

[0002] Hydraulic forming is an advanced manufacturing technology that uses liquid as a force transmission medium to force metal blanks to conform to the mold surface under pressure, thereby forming the desired part shape. Depending on the initial shape of the blank, hydraulic forming is mainly divided into two technical branches: one is internal high-pressure forming using metal tubes as blanks, and the other is liquid-filled stretch forming using metal sheets as blanks.

[0003] In the existing technology, the technical principles and process paths of the forming processes for the two products mentioned above are completely different:

[0004] Tube products (internal high-pressure forming): Liquid medium is injected into the tube blank, and ultra-high pressure is applied to the tube and pressure is released in multiple directions. At the same time, the axial feeding system cooperates with the feeding to make the tube wall material flow into the mold cavity.

[0005] Plate products (liquid-filled stretch forming): The liquid medium acts on one of the surfaces of the plate blank, providing passive back pressure or active pressure in a relatively uniform direction. It often adopts an open or semi-closed form of semi-mold forming (one of the punch or die is a liquid cavity).

[0006] The different physical forming processes of these two different shaped blanks lead to significant differences in the integration requirements of the process carrier—the hydraulic equipment. For a long time, mature hydraulic equipment on the market has been limited to single-function specialized machines, such as high-pressure forming machines for pipes or liquid-filled stretching machines for plates. For manufacturing companies that need to process both pipe and plate parts simultaneously (such as automotive parts, aerospace structural components, and composite components for home appliances), they can only purchase two independent specialized machines. This not only results in high equipment investment costs and large workshop footprints, but more importantly, it prevents rapid production switching: when product orders switch between pipe and plate parts, it requires waiting for the other machine to become available, changing tooling, and readjusting, leading to low production organization efficiency and severely restricting flexible manufacturing capabilities.

[0007] Therefore, the market urgently needs a composite forming equipment that can simultaneously accommodate two completely different forming processes for tubes and sheets, achieving "multi-purpose use and rapid production switchover." However, integrating two conflicting process requirements into one machine faces significant technical challenges:

[0008] 1. Incompatible structural design: Liquid sheet metal filling and stretching requires vertical and uniform clamping force, prioritizing rigidity in the machine body; High-pressure forming of tubing requires withstanding extremely high horizontal internal expansion forces, placing higher demands on the machine body's fatigue strength and multi-directional stress stability. Traditional single-structure machine bodies cannot simultaneously meet the extreme requirements of both rigidity and strength.

[0009] 2. Product forming compatibility issues: The two forming processes have different power sources (hydraulic systems), action sequences (pressurization, material replenishment, and depressurization), sealing methods, and mold mating relationships. Simply combining the two systems will result in bulky equipment, chaotic control logic, and mutual interference between actions.

[0010] In view of this, developing a tube sheet composite forming equipment that can systematically solve the above-mentioned integration problems and truly achieve reliability, efficiency and flexibility is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0011] In order to overcome the shortcomings of the prior art, one of the objectives of the present invention is to provide a compact tube sheet composite forming hydraulic system.

[0012] The second objective of this invention is to provide a control method for a compact tube sheet composite forming hydraulic system.

[0013] One of the objectives of this invention is achieved by the following technical solution: a compact tube sheet composite forming hydraulic system, comprising:

[0014] A tube-plate composite forming device includes a machine body and a worktable. The machine body is a closed frame structure, and the worktable is set inside the closed frame structure. The worktable has a common station for tube forming and plate forming.

[0015] Two sets of hydraulic devices, namely a vertical hydraulic device and a horizontal hydraulic device, are provided. The vertical hydraulic device is set in the vertical direction of the closed frame structure and is used to apply vertical pressure to the mold. The horizontal hydraulic device is set in the horizontal direction of the closed frame structure and is used to apply horizontal pressure to the mold.

[0016] The numerical control system is electrically connected to the hydraulic device and the fluid delivery device, respectively;

[0017] When processing pipe fittings, the mold containing the pipe fittings is installed on a common station. The CNC system controls the vertical hydraulic device and the horizontal hydraulic device to apply pressure to the mold and inject liquid into the center of the pipe fitting, so that the pipe wall expands outward to fit the mold cavity and completes the pipe forming.

[0018] When processing sheet metal, the mold containing the sheet metal is installed in a common workstation. The CNC system controls the vertical hydraulic device to apply pressure to the mold, so that the sheet metal and the mold cavity are fully fitted together, and the sheet metal is formed.

[0019] Furthermore, the machine body includes a tie rod assembly, an upper beam, a middle beam, a lower beam, and a mold pad. The tie rod assembly adopts a column-type pre-tightening tie rod structure and is set between the upper beam and the lower beam. Its two ends are fastened to the upper beam and the lower beam respectively through pre-tightening cylinders to form a closed frame structure.

[0020] The vertical hydraulic device includes an upper composite cylinder and a lower cylinder assembly. The upper composite cylinder is a multi-stage piston cylinder, which is fixed to the upper beam. Its power output end is connected to the middle beam and the mold pad respectively. The mold pad is movably inserted inside the middle beam. The middle beam and the mold pad move up and down independently or move up and down synchronously under the drive of the upper composite cylinder. The lower cylinder assembly is located inside the lower beam, and the worktable is located on the surface of the lower beam. The power output end of the lower cylinder assembly is connected to two sets of ejector pins respectively. The two sets of ejector pins move up and down independently under the drive of the lower cylinder assembly.

[0021] The horizontal hydraulic device is movably mounted on both sides of the worktable and located between adjacent tie rod assemblies.

[0022] Furthermore, the upper composite cylinder includes a primary cylinder and a secondary cylinder disposed inside the primary cylinder; the primary cylinder includes a primary cylinder barrel, and a secondary cylinder barrel is fixedly disposed inside the primary cylinder barrel; a primary cylinder piston rod is movably nested between the inner wall of the primary cylinder barrel and the outer wall of the secondary cylinder barrel; a secondary cylinder piston rod is movably nested inside the secondary cylinder barrel; the primary cylinder piston rod is fixedly connected to the middle beam, driving the middle beam to move up and down in the vertical direction; the secondary cylinder piston rod is fixedly connected to the mold pad, driving the mold pad to move up and down in the vertical direction.

[0023] The second-stage cylinder barrel is fixedly provided with a second-stage cylinder quick rod at the top end, and the end of the second-stage cylinder quick rod passes through the piston rod of the second-stage cylinder. The second-stage cylinder quick rod has an oil inlet and outlet chamber. The second-stage cylinder barrel is also provided with a displacement sensor and an anti-rotation rod to prevent the displacement sensor from axially shifting. The ends of the displacement sensor and the anti-rotation rod both pass through the piston rod of the second-stage cylinder.

[0024] Furthermore, the tube sheet composite forming device also includes a connecting locking cylinder disposed between the middle beam and the mold pad. The connecting locking cylinder is installed on the middle beam or the mold pad and is used to mechanically lock the middle beam and the mold pad or to loosen them when needed.

[0025] The tube sheet composite forming device may also include at least one safety cylinder assembly, which is a hydraulic locking cylinder or a mechanical safety lock. The safety cylinder assembly is arranged in a horizontal direction, and the middle beam or the tie rod assembly is provided with a locking hole. The locking head of the safety cylinder assembly can extend into the locking hole.

[0026] Furthermore, the tube sheet composite forming device also includes an upper hydraulic cushion and a lower hydraulic cushion. The upper hydraulic cushion is located at the bottom of the middle beam, and the lower beam has a hollow structure in the middle. The lower hydraulic cushion is slidably installed in the hollow structure of the lower beam. Multiple vertically arranged hydraulic cushion top columns are provided in the hollow structure. Each hydraulic cushion top column passes through the lower hydraulic cushion. The bottom of the hydraulic cushion top column is fixedly connected to the lower beam, and the top of the hydraulic cushion top column supports the worktable. Multiple shock-absorbing rods are provided at the bottom of the lower hydraulic cushion according to the need for vertical pressure.

[0027] Furthermore, the tube sheet composite forming device also includes a quick mold changing device for quickly changing different molds. The quick mold changing device includes a guide rail, a movable locking head, and a lifting cylinder. The guide rail is set on the surface of the lower beam and extends horizontally outward from the lower beam. The bottom of the worktable is provided with rollers, which cooperate with the guide rail to slide, so that the worktable slides horizontally back and forth along the length of the guide rail. Each roller corresponds to a movable locking head and a lifting cylinder to lock and unlock. Several movable locking heads are set on the guide rail located on the surface of the lower beam. The lifting cylinder drives the movable locking heads to move up and down in the vertical direction. The top of the movable locking head is recessed with a groove. When the worktable returns to the working position on the lower beam, the movable locking head sinks down, embedding the roller on the worktable into the groove and locking it in place. When changing molds, the movable locking head lifts the rollers out of the groove, so that the worktable slides back and forth on the guide rail.

[0028] Furthermore, the tube sheet composite forming device also includes a water circulation system, which includes a perimeter water tank, a pre-storage water tank, and a transition water tank surrounding the workbench. The workbench surface is provided with multiple drainage channels, and each drainage channel ultimately flows from the surrounding outlets to the perimeter water tank. The perimeter water tank is connected to the pre-storage water tank through a first pipe. The liquid in the pre-storage water tank is directly connected to the mold located on the workbench through a second pipe, or after being pressurized by a booster, it is connected to the mold through a third pipe. The transition water tank is connected to the mold through a fourth pipe to output a temporary water source. The transition water tank is directly connected to a tap water pipe, or it is connected to the pre-storage water tank through a fifth pipe to replenish the return water source.

[0029] The pre-stored water tank is divided into a first water tank and a second water tank. The first water tank is used to recover the liquid discharged from each mold, and the second water tank is connected to the booster. The first water tank is divided into multiple chambers, and each chamber is equipped with a filter purifier. The water that has been purified through multiple stages flows to the second water tank.

[0030] The second objective of this invention is achieved by the following technical solution: a control method for the compact tube sheet composite forming hydraulic system as described above, comprising the following steps:

[0031] The system receives the processing mode selected by the user, which includes the high-pressure forming mode inside the pipe, the liquid-filled deep drawing mode of the sheet metal, and the liquid-free deep drawing mode of the sheet metal.

[0032] Based on the user's selected mode, the CNC system retrieves the corresponding process path parameters from the pre-stored process database: When the user selects the high-pressure forming mode inside the pipe, the CNC system retrieves the process parameters corresponding to the current pipe material, diameter, and wall thickness from the pre-stored high-pressure forming process database inside the pipe, including the internal pressure curve, axial feed force curve, and mold clamping force; when the user selects the liquid-filled deep drawing mode for sheet metal, the CNC system retrieves the process parameters corresponding to the current sheet metal material and thickness from the pre-stored liquid-filled deep drawing process database for sheet metal, including the blank holder force curve, mold liquid chamber pressure curve, and the downward speed and pressure curve of the upper composite cylinder; when the user selects the liquid-free deep drawing forming mode for sheet metal, the CNC system retrieves the process parameters corresponding to the current sheet metal material and thickness from the pre-stored liquid-free deep drawing forming process database for sheet metal, including the blank holder force curve and the downward speed and pressure curve of the upper composite cylinder.

[0033] Based on the process path parameters, the CNC system controls the hydraulic device and the fluid delivery device to work together to complete the forming of the corresponding pipe or plate.

[0034] Furthermore, in the control method, when the user selects the internal high-pressure forming mode, the lower mold of the internal high-pressure mold containing the pipe fitting is fixedly installed on the worktable. The CNC system locks the middle beam and the mold pad to form a one-piece movable beam. The upper mold of the internal high-pressure mold is fixedly installed on the one-piece movable beam. The upper composite cylinder drives the one-piece movable beam to move down synchronously. The upper mold moves down and closes with the lower mold, providing a mold-closing and locking force not less than the mold-opening force generated by the highest pressure inside the pipe. Then, the horizontal hydraulic devices on the left and right sides feed axially towards the center of the pipe fitting. The plugs at the ends of the horizontal hydraulic devices press the two ends of the pipe blank to form a high-pressure seal. The liquid delivery device injects low-pressure liquid into the pipe blank and pipe fitting. The CNC system raises the pressure of the liquid inside the pipe to the ultra-high pressure set value according to the pressure curve inside the pipe. At the same time, it controls the horizontal hydraulic devices on both sides to perform axial feeding according to the axial feed force curve, so that the pipe wall expands outward under the action of internal pressure and fits the mold cavity, completing the internal high-pressure forming of the pipe fitting.

[0035] When the user selects the liquid-filled deep drawing forming mode, the lower die of the liquid-filled stretching die containing the sheet metal is fixedly installed on the worktable, and the upper die of the liquid-filled stretching die is fixedly installed on the die pad. The CNC system unlocks the middle beam from the die pad, and the middle beam and die pad move up and down respectively under the drive of the first-stage cylinder and the second-stage cylinder. The second-stage cylinder drives the die pad and the upper die to move down until they contact the sheet metal and then stop temporarily. At the same time, the first-stage cylinder drives the middle beam down to press the edge of the sheet metal against the lower die to provide pressure for the blank holder ring, and establishes the initial blank holder force according to the blank holder force curve. The liquid infusion device starts rapid liquid filling, injecting liquid medium into the mold liquid chamber of the liquid-filled stretching die, and the mold liquid chamber pressure rises according to the preset mold liquid chamber pressure curve. According to the preset downward speed and pressure curve of the upper composite cylinder, the upper die continues to move down to pull the sheet metal into the lower die. The CNC system collects feedback signals of mold liquid chamber pressure and displacement signals in real time, so that the sheet metal is molded under hydraulic action. The mold liquid chamber pressure rises to the highest set value and is held for a preset time to allow the sheet metal to fully adhere to the die, completing the liquid-filled deep drawing forming of the sheet metal.

[0036] When the user selects the liquid-free deep drawing mode, the lower die of the liquid-free stretching die containing the sheet metal is fixedly installed on the worktable, and the upper die of the liquid-free stretching die is fixedly installed on the die pad. The CNC system unlocks the middle beam from the die pad, and the middle beam and die pad move up and down respectively under the drive of the first-stage cylinder and the second-stage cylinder. The second-stage cylinder drives the die pad and the upper die to move down until they contact the sheet metal and then stop temporarily. At the same time, the first-stage cylinder drives the middle beam down to press the edge of the sheet metal against the lower die to provide pressure for the blank holder ring, and establishes the initial blank holder force according to the blank holder force curve. According to the preset downward speed and pressure curve of the upper composite cylinder, the upper die continues to move down to pull the sheet metal into the lower die. The CNC system collects feedback signals of the mold fluid chamber pressure and displacement signals in real time, so that the sheet metal is formed by hydraulic action. The mold fluid chamber pressure rises to the highest set value and is held for a preset time to ensure that the sheet metal is fully attached to the die, thus completing the liquid-free deep drawing of the sheet metal.

[0037] When switching between the above processing modes, the corresponding mold must be replaced.

[0038] Furthermore, when switching processing modes, the control method further includes: after the CNC system detects that the beam is locked onto the tie rod assembly by a safety component to ensure that the safety conditions for mold replacement are met, the robot or a person replaces the mold.

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0040] 1. It achieves multi-purpose functionality and rapid production switching, significantly reducing overall costs and greatly improving production flexibility:

[0041] To address the current requirements for forming tube sheet products, the need to purchase or customize multiple specialized machines leads to high costs and large footprints. This application improves the machine structure (simultaneously meeting vertical and horizontal force requirements) and the forming action compatibility structure (simultaneously allowing multiple forming processes to perform their respective actions), highly integrating multiple functions such as high-pressure forming inside the tube, active / passive liquid-filled stretching of the sheet, and forward and reverse stretching forming of the sheet without liquid media into a single machine. Users only need one machine to complete the processing of parts that originally required multiple production lines, reducing equipment investment costs by approximately 50-70% and reducing the footprint by more than 60%, significantly reducing the asset burden and workshop layout complexity for manufacturing enterprises.

[0042] Furthermore, when switching between pipe fittings and sheet metal parts, operators only need to select the corresponding mode on the control interface of the composite molding machine, and the system can automatically reconfigure the hydraulic circuit, control parameters, and safety interlocks without the need for hardware modifications or lengthy process debugging. The time for a single production switchover can be shortened from several hours (replacing the entire equipment and re-debugging) to less than 15 minutes, truly meeting the needs of modern manufacturing models that require multiple varieties, small batches, and high flexibility.

[0043] 2. Resolving integration conflicts ensures the high reliability and precision of the composite forming hydraulic system:

[0044] At the machine body structure level: This application adopts a column-type pre-tightening tie rod structure for the machine body, especially the pre-tightening structure between the tie rod assembly and the upper and lower beams. Through the locking structure of the pre-tightening cylinder and the pre-tightening nut, the entire machine body forms a closed frame, which provides the high vertical rigidity required for sheet metal forming and the high level of fatigue resistance required for tube forming. This ensures the precise closure of the mold cavity under both process modes, and the forming accuracy is improved by more than 30% compared with the traditional simple superimposed structure.

[0045] Regarding the compatibility structure of forming actions, this application improves the structure of the middle beam and the lower beam. Specifically, the middle beam is designed as a split upper composite cylinder that simultaneously incorporates a multi-stage piston cylinder. That is, the mold pad can be movably inserted inside the middle beam. The middle beam and the mold pad can move up and down independently or move up and down synchronously under the drive of the upper composite cylinder. This structural improvement can adapt to the operation of at least two forming actions. At the same time, this application also designs the lower beam as a hollow structure and introduces rigid reinforcement structures such as a lower hydraulic cushion, a hydraulic cushion top column, and a shock absorber.

[0046] When tubular products are high-pressure formed, the middle beam and mold pad are locked by the connecting locking cylinder. The upper composite oil cylinder drives the two to move up and down synchronously. Combined with the lower cylinder assembly and reinforcing structure in the lower beam, a uniform and high-pressure clamping force is provided to the high-pressure forming mold. At the same time, the horizontal hydraulic device applies pressure to the inside of the pipe in multiple directions to release pressure, so that the pipe wall material flows into the mold cavity.

[0047] When sheet products are filled with liquid and stretched, the middle beam and mold pad are unlocked by the locking cylinder and then moved up and down by the upper composite oil cylinder. Combined with the lower cylinder assembly and reinforcing structure in the lower beam, they provide corresponding clamping force and blank holder force.

[0048] When plate-type products are stretched and formed without liquid medium, the extension and retraction of two sets of ejector pins are independently controlled by the lower cylinder assembly. After the two sets of ejector pins pass through the worktable, they clamp and fix the plate, thus realizing the stretching and forming of the medium in both directions.

[0049] This application breaks down the technical barriers between tubular and plate hydraulic forming equipment through structural integration and improvement, providing the market with an efficient and flexible tubular-plate composite forming solution with significant technological advancements and industrial application value. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of the structure of the tube sheet composite forming device according to a preferred embodiment of the present invention;

[0051] Figure 2 This is a schematic cross-sectional view of the tube sheet composite forming device according to a preferred embodiment of the present invention;

[0052] Figure 3 for Figure 2 Enlarged view of point A in the middle;

[0053] Figure 4 This is a schematic diagram of the cross-sectional structure of the fuselage according to a preferred embodiment of the present invention;

[0054] Figure 5 for Figure 4 Enlarged view of point B in the middle;

[0055] Figure 6 This is a front view of the machine body, worktable, vertical hydraulic device, and horizontal hydraulic device according to a preferred embodiment of the present invention;

[0056] Figure 7 This is a schematic cross-sectional view of a preferred embodiment of the vertical hydraulic device of the present invention;

[0057] Figure 8 for Figure 7 Enlarged view of point C in the middle;

[0058] Figure 9 for Figure 7 Enlarged view of point D in the middle;

[0059] Figure 10 This is a schematic diagram of the sliding adjustment structure according to a preferred embodiment of the present invention;

[0060] Figure 11 This is a schematic diagram of the cross-sectional structure of the beam in a preferred embodiment of the present invention;

[0061] Figure 12 This is a schematic diagram of the cross-sectional structure of the beam at another angle in a preferred embodiment of the present invention;

[0062] Figure 13 This is a schematic cross-sectional view of the composite cylinder in a preferred embodiment of the present invention;

[0063] Figure 14 This is a schematic diagram of the connection structure between the composite cylinder and the cylinder control system in a preferred embodiment of the present invention;

[0064] Figure 15 This is a schematic diagram of the disassembled structure of the workbench, lower cylinder assembly, and lower beam according to a preferred embodiment of the present invention.

[0065] Figure 16 This is a schematic diagram of the structure of the quick mold changing device according to a preferred embodiment of the present invention;

[0066] Figure 17 for Figure 16 Enlarged view of point E in the middle;

[0067] Figure 18 This is a schematic diagram of the built-in transmission component in the quick mold changing device of the present invention, according to a preferred embodiment.

[0068] Figure 19 This is a schematic diagram of the water circulation system in the tube sheet composite forming device according to a preferred embodiment of the present invention;

[0069] Figure 20 for Figure 19 Enlarged view of point F in the middle;

[0070] Figure 21 This is a schematic diagram of the water flow direction of the water circulation system according to a preferred embodiment of the present invention;

[0071] Figure 22 This is a schematic diagram of the tube sheet composite forming device in the liquid-free deep drawing forming mode, which is a preferred embodiment of the present invention.

[0072] In the picture:

[0073] 100. Tube-sheet composite forming device; 100G. Shared workstation;

[0074] 1. Machine body; 11. Tie rod assembly; 111. Prestressed tie rod; 112. Preload nut; 113. Preload cylinder; 1131. Preload cylinder body; 1132. Preload cylinder piston rod; 1133. Preload cylinder support sleeve; 114. Sliding adjustment structure; 1141. First guide rail; 1142. Second guide rail; 1143. Adjusting block; 1144. First fixing plate; 1145. Second fixing plate; 1146. First insertion joint; 1147. Second insertion joint; 12. Upper beam; 13. Middle beam; 14. Lower beam; 141. Hollow structure; 15. Mold pad;

[0075] 2. Workbench; 21. Drainage channel;

[0076] 3. Vertical hydraulic device; 31. Upper compound cylinder; 311. Primary cylinder; 3111. Primary cylinder barrel; 3112. Primary cylinder piston rod; 312. Secondary cylinder; 3121. Secondary cylinder barrel; 3122. Secondary cylinder piston rod; 313. Secondary cylinder quick rod; 314. Displacement sensor; 315. Anti-rotation rod; 32. Lower cylinder assembly; 321. Primary lower cylinder; 322. Secondary lower cylinder; 33. First ejector pin; 34. Second ejector pin; 35. Return quick cylinder; 36. Oil cooler; 37. Cylinder control system;

[0077] 4. Horizontal hydraulic device;

[0078] 5. Connect the locking cylinder;

[0079] 6. Safety cylinder assembly;

[0080] 7. Install the hydraulic cushion;

[0081] 8. Lower hydraulic cushion; 81. Hydraulic cushion top column; 82. Shock absorber rod; 83. Slider assembly;

[0082] 9. Quick mold change device; 91. Guide rail; 92. Movable locking head; 921. Slot; 93. Lifting cylinder; 94. Roller; 95. Built-in transmission assembly; 951. Drive motor; 952. Drive gear; 953. Driven gear; 954. Linkage shaft;

[0083] 10. Water circulation system; 101. Surrounding water tank; 102. Pre-storage water tank; 1021. First water tank; 1021a. Chamber; 1021b. Filter purifier; 1022. Second water tank; 103. Transition water tank; 104. First pipe; 105. Second pipe; 106. Third pipe; 107. Fourth pipe; 108. Fifth pipe; 109. Booster;

[0084] 200. Hydraulic device;

[0085] 300. Numerical control system;

[0086] 400. Infusion device;

[0087] 500. Working foundation pit;

[0088] G1, Internal high-pressure mold; G2, Medium-free stretching mold. Detailed Implementation

[0089] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0090] Example 1

[0091] like Figures 1-22 As shown, a compact tube sheet composite forming hydraulic system includes:

[0092] The tube-plate composite forming device 100 includes a machine body 1 and a worktable 2. The machine body 1 is a closed frame structure, and the worktable is set inside the closed frame structure. The worktable has a common station 100G for tube forming and plate forming.

[0093] Two sets of hydraulic devices 200 are a vertical hydraulic device 3 and a horizontal hydraulic device 4. The vertical hydraulic device 3 is set in the vertical direction of the closed frame structure and is used to apply vertical pressure to the mold. The horizontal hydraulic device is set in the horizontal direction of the closed frame structure and is used to apply horizontal pressure to the mold.

[0094] The infusion device 400 is used to inject liquid into the mold to provide the liquid pressure required for molding. In this embodiment, the infusion device 400 is a conventional water system, connected to a conventional water tank or tap water pipe.

[0095] The CNC system 300 is electrically connected to the hydraulic device and the fluid delivery device, respectively. The CNC system 300 has at least the following working modes: internal high-pressure forming mode for pipes; active / passive fluid filling deep drawing forming mode for plates; and liquid-free forward and reverse deep drawing forming mode for plates. It also has at least a preset database of internal high-pressure forming processes for pipes, a database of fluid filling deep drawing processes for plates, and a database of liquid-free forward and reverse deep drawing processes. The CNC system is configured to automatically call the corresponding process path according to the working mode selected by the user, and control the coordinated action of hydraulic valve components, pressure sensors, displacement sensors, and other accessories in the hydraulic device in real time to meet the mass production requirements of position, pressure, and forming accuracy under various working modes.

[0096] When processing pipe fittings, the mold containing the pipe fittings is installed on the common station 100G. The CNC system controls the vertical hydraulic device 3 and the horizontal hydraulic device to apply pressure to the mold, and controls the liquid delivery device to inject liquid into the center of the pipe fitting, so that the pipe wall expands outward to fit the mold cavity, thus completing the pipe forming.

[0097] When processing sheet metal, the mold containing the sheet metal is installed in the common station 100G. The CNC system controls the vertical hydraulic device 3 to apply pressure to the mold. If necessary, the liquid delivery device is controlled to inject liquid into the mold so that the sheet metal and the mold cavity can fit together fully and the sheet metal is formed.

[0098] In this embodiment, the machine body 1 includes a tie rod assembly 11, an upper beam 12, a middle beam 13, a lower beam 14, and a mold pad 15. The tie rod assembly 11 adopts a column-type pre-tightening tie rod structure and is set between the upper beam 12 and the lower beam 14. Its two ends are fastened to the upper beam 12 and the lower beam 14 respectively through pre-tightening cylinders 113 to form a closed frame structure.

[0099] The vertical hydraulic device 3 includes an upper composite cylinder 31 and a lower cylinder assembly 32. The upper composite cylinder 31 is a multi-stage piston cylinder, which is fixed to the upper beam 12. Its power output end is connected to the middle beam 13 and the mold pad 15 respectively. The mold pad 15 is movably inserted inside the middle beam 13. The middle beam 13 and the mold pad 15 move up and down respectively under the drive of the upper composite cylinder 31, or they move up and down synchronously. The lower cylinder assembly 32 is disposed inside the lower beam 14. The worktable 2 is disposed on the surface of the lower beam 14. The power output end of the lower cylinder assembly 32 is connected to two sets of ejector pins respectively. The two sets of ejector pins are the first ejector pin 33 and the second ejector pin 34. The first ejector pin 33 and the second ejector pin 34 are both movably inserted inside the lower beam 14 and the worktable 2. The two sets of ejector pins move up and down respectively under the drive of the lower cylinder assembly 32.

[0100] In some implementations, the horizontal hydraulic device 4 is designed to be movably mounted on both sides of the workbench 2 and located between adjacent tie rod assemblies 11. This structural design can reduce the interference of the shared workstation 100G in different working modes.

[0101] This application integrates multiple functions into a single machine by improving the machine body structure (simultaneously satisfying vertical and horizontal force requirements) and the forming action compatibility structure (simultaneously allowing various forming processes to perform their respective actions). These functions include high-pressure forming of pipes, active / passive liquid-filled stretching of sheets, and forward and reverse stretching forming of sheets without liquid media. Users only need one machine to complete the processing of parts that originally required multiple production lines, reducing equipment investment costs by approximately 50-70% and floor space by more than 60%, significantly reducing the asset burden and workshop layout complexity for manufacturing enterprises.

[0102] Specifically, at the level of the machine body structure: the machine body 1 of this application adopts a column-type pre-tightening tie rod structure, especially the pre-tightening structure between the tie rod assembly 11 and the upper beam 12 and the lower beam 14. The entire machine body 1 forms a closed frame, which provides the high vertical rigidity required for sheet metal forming and the high level of fatigue resistance required for tube forming. This ensures the precise closure of the mold cavity under both process modes, and the forming accuracy is improved by more than 30% compared with the traditional simple superimposed structure.

[0103] Regarding the compatibility structure of forming actions, this application improves the structure of the middle beam 13 and the lower beam 14. Specifically, the middle beam 13 is designed as a split upper composite cylinder 31 that simultaneously introduces a multi-stage piston cylinder. That is, the mold pad 15 can be movably inserted inside the middle beam 13. The middle beam 13 and the mold pad 15 move up and down on their own or move up and down synchronously under the drive of the upper composite cylinder 31. This structural improvement can adapt to the operation of at least two forming actions. At the same time, this application also designs the lower beam 14 as a hollow structure 141 and introduces a lower cylinder assembly 32, a lower hydraulic cushion 8, and other driving and rigidity strengthening structures.

[0104] The pre-tightening structure of this application is a locking structure in which a pre-tightening cylinder 113 and a pre-tightening nut 112 cooperate with each other. Specifically, it includes a prestressed tie rod 111 disposed in the tie rod assembly 11, pre-tightening nuts 112 threadedly connected to both ends of the prestressed tie rod 111, and a pre-tightening cylinder 113 disposed on the upper part of the pre-tightening nut 112. The pre-tightening cylinder 113 includes a pre-tightening cylinder body 1131, a pre-tightening cylinder piston rod 1132, and a pre-tightening cylinder support sleeve 1133. In this embodiment, after the upper beam 12 and the lower beam 14 are fixed to the tie rod assembly 11 respectively, the pre-tightening nuts 112 are screwed to the upper and lower ends of the prestressed tie rod 111 respectively. Then, by adjusting the pressure of the pre-tightening cylinder 113, the pre-tightening cylinder piston rod 1132 locks the pre-tightening nuts 112 in the vertical direction, thereby providing the closed frame with the necessary vertical and horizontal force.

[0105] In addition, in some embodiments, to address the shortcomings of poor operational stability and difficulty in guaranteeing guiding accuracy in the multifunctional large system of the present invention, this application provides an adjustable sliding adjustment structure 114 on the tie rod assembly 11. The sliding adjustment structure 114 includes a first guide rail 1141 mounted on the tie rod assembly 11 and a second guide rail 1142 mounted on the central beam 13, wherein the first guide rail 1141 and the second guide rail 1142 are slidably connected. The sliding adjustment structure 114 further includes an adjustment block 1143 for adjusting the gap between the sliding contact surfaces of the first guide rail 1141 and the second guide rail 1142. The adjustment block 1143 is provided with a guide slope. Specifically, in this example, the first guide rail 1141 and the second guide rail 1142 are respectively provided with a first fixing piece 1144 and a second fixing piece 1145 on the side away from the sliding contact surface. A first insertion joint 1146 is left between the first fixing piece 1144 and the first guide rail 1141, and a second insertion joint 1147 is left between the second fixing piece 1145 and the second guide rail 1142. The adjusting block 1143 is inserted into the first insertion joint 1146 and the second insertion joint 1147 respectively. By adjusting the insertion depth of the adjusting block 1143, the guide slope of the adjusting block 1143 is pressed against the two guide rails, thereby realizing the function of adjusting the gap between the two guide rails. The clearance between the slider and the guide rail can be adjusted at any time according to the actual working conditions (such as device heating, wear, etc.), and always maintain a guide state with no gap or a small gap. This solves the problem of swaying and jamming when the middle beam 13 moves, and makes the middle beam 13 rise and fall smoothly, thereby ensuring the stability of the liquid filling forming process of the plate and the consistency of the parts.

[0106] As a further preferred embodiment, the upper composite cylinder 31 of this application includes a primary cylinder 311 and a secondary cylinder 312 disposed inside the primary cylinder 311. The primary cylinder 311 includes a primary cylinder barrel 3111, and a secondary cylinder barrel 3121 is fixedly disposed inside the primary cylinder barrel 3111. A primary cylinder piston rod 3112 is movably nested between the inner wall of the primary cylinder barrel 3111 and the outer wall of the secondary cylinder barrel 3121. A secondary cylinder piston rod 3122 is movably nested inside the secondary cylinder barrel 3121. The primary cylinder piston rod 3112 is fixedly connected to the middle beam 13, driving the middle beam 13 to move up and down in the vertical direction. The secondary cylinder piston rod 3122 is fixedly connected to the mold pad 15, driving the mold pad 15 to move up and down in the vertical direction. This structure simplifies the hydraulic system by integrating the primary annular cylinder system (pressing) and the secondary piston cylinder system (tensioning) into one unit. The pressing force and the tensioning force do not interfere with each other and are independently controlled by two independent cylinder control systems 37.

[0107] In some embodiments, a secondary cylinder quick rod 313 is fixedly provided at the top end of the secondary cylinder barrel 3121. The end of the secondary cylinder quick rod 313 extends into the secondary cylinder piston rod 3122 of the secondary cylinder 312. An oil inlet / outlet chamber is provided within the secondary cylinder quick rod 313. A displacement sensor 314 and an anti-rotation rod 315 to prevent axial displacement of the displacement sensor 314 are also provided inside the secondary cylinder barrel 3121. The ends of both the displacement sensor 314 and the anti-rotation rod 315 extend into the secondary cylinder piston rod 3122. This structural design of the secondary cylinder quick rod 313 allows for rapid downward movement or rapid reset of the secondary cylinder piston rod 3122 by supplying hydraulic oil into it, thus improving the working efficiency of the secondary cylinder piston rod 3122. This application achieves precise control of the end position through the displacement sensor 314, realizing an organic combination of rapid descent and precise stopping, resolving the contradiction of traditional hydraulic presses where speed is not accurate and accuracy is not fast. By adding an anti-rotation structure, the circumferential rotation of the piston rod of the tension cylinder that may occur during operation can be reliably constrained, and the torsional stress on the displacement sensor 314 (such as the sensor waveguide) can be reduced to a minimum or even eliminated. The overall structure is compact and does not occupy the space of any additional components, so that the composite cylinder can maintain stable and reliable operation in the medium to long term, greatly extending its service life and reducing the frequency of device maintenance and downtime.

[0108] In some specific embodiments, the tube sheet composite forming device 100 further includes a connecting locking cylinder 5 disposed between the middle beam 13 and the mold pad 15. The connecting locking cylinder 5 is installed on the middle beam 13 or the mold pad 15 and is used to mechanically lock the middle beam 13 and the mold pad 15 or to loosen them when needed.

[0109] The tube sheet composite forming device 100 may also include at least one safety cylinder assembly 6, which is horizontally disposed on the middle beam 13 or the tie rod assembly 11. When the safety cylinder assembly 6 is disposed on the middle beam 13, the tie rod assembly 11 has a locking hole; when the safety cylinder assembly 6 is disposed on the tie rod assembly 11, the middle beam 13 has a locking hole, and the locking head of the safety cylinder assembly 6 can extend into the locking hole. The composite cylinder 31 in this application is heavy and bulky. By designing the safety cylinder assembly 6, when it is necessary to switch working modes, change molds, or when the tube or plate requires high-pressure holding treatment, the middle beam 13 is mechanically locked, effectively preventing the oil circuit of the upper composite cylinder 31 from losing pressure or the seal from failing, which could lead to the accidental rebound or fall of the middle beam 13, thus ensuring the safety of the operators and the device. The safety cylinder assembly 6 is a mechanical safety lock or a hydraulic locking cylinder, with the hydraulic locking cylinder using a hydraulic oil circuit independent of the upper composite cylinder 31.

[0110] As a further preferred embodiment, the tube sheet composite forming device 100 also includes a return rapid cylinder 35, the cylinder body of which is fixed to the upper beam 12, and its telescopic rod is connected to the middle beam 13 in a transmission manner; the return rapid cylinder 35 is controlled by an independent hydraulic cylinder control system 37 and is not interfered with by the hydraulic cylinder control system 37 of the upper composite hydraulic cylinder 31.

[0111] The tube sheet composite forming apparatus 100 may also include an oil cooler 36, which is connected to the upper composite cylinder 31 and is used to provide a cooling source for the composite cylinder. The cooler includes a circulation pipeline and a temperature control unit, used to control the operating temperature of the composite cylinder within a set range.

[0112] In this invention, during the liquid-filled deep drawing forming of sheet metal, the liquid-filled deep drawing forming is divided into active liquid-filled deep drawing forming and passive liquid-filled deep drawing forming, depending on the design position of the upper and lower dies, the concave and convex shape structure, and the design position of the liquid chamber of the liquid-filled drawing die. Both liquid-filled deep drawing forming modes can be realized by the hydraulic system of this invention.

[0113] The lower cylinder assembly 32 is fixedly installed on the lower beam 14. The lower cylinder assembly 32 includes a primary lower cylinder 321 and a secondary lower cylinder 322. The piston rod of the primary lower cylinder 321 is drivenly connected to the first ejector pin 33, and the piston rod of the secondary lower cylinder 322 is drivenly connected to the second ejector pin 34. In this embodiment, three lower cylinders are provided below the lower beam 14: the primary lower cylinders 321 located on both sides are preferably low-pressure, high-flow-rate cylinders, used for active liquid filling and deep drawing to quickly provide blank holder force or demolding force; the secondary lower cylinder 322 located in the middle is preferably a high-pressure, low-flow-rate cylinder, used for auxiliary pressurization, which can increase the punching force or demolding force by up to 30%. The three lower cylinders are used in a shared or coordinated manner, which is suitable for processing large-volume workpieces or plates made of highly elastic materials.

[0114] As a further preferred embodiment, the tube sheet composite forming device 100 also includes an upper hydraulic cushion 7 and a lower hydraulic cushion 8. The upper hydraulic cushion 7 is located at the bottom of the middle beam 13, and the lower beam 14 has a hollow structure 141 in the middle position. The lower hydraulic cushion 8 is slidably installed in the hollow structure 141 of the lower beam 14 via a slider assembly 83. Multiple vertically arranged hydraulic cushion top columns 81 are provided within the hollow structure 141, each hydraulic cushion top column 81 passing through the lower hydraulic cushion 8. The bottom of each hydraulic cushion top column 81 is fixedly connected to the lower beam 14, and the top of each hydraulic cushion top column 81 supports the worktable 2. Multiple shock-absorbing rods 82 are provided at the bottom of the lower hydraulic cushion 8 according to the need for vertical pressure. This application compensates for structural stiffness loss and prevents deformation under heavy loads by setting hydraulic cushion top columns 81 in the hollow area of ​​the lower beam 14. Simultaneously, the design of the shock-absorbing rods 82 ensures the processing accuracy of the workpiece and the long-term stability of the equipment. The two work together to enhance structural rigidity and guarantee long-term accuracy.

[0115] As a further preferred embodiment, the tube sheet composite forming device 100 also includes a quick mold changing device 9 for quickly changing different molds. The quick mold changing device 9 includes a guide rail 91, a movable locking head 92, and a lifting cylinder 93. The guide rail 91 is disposed on the surface of the lower beam 14 and extends horizontally outward from the lower beam 14. The bottom of the worktable 2 is provided with rollers 94, which slide in cooperation with the guide rail 91 to allow the worktable 2 to slide horizontally back and forth along the length of the guide rail 91. Each roller 94 corresponds to one movable locking head 92 and one lifting cylinder. In conjunction with locking and unlocking actions, several movable locking heads 92 are mounted on the guide rail 91 located on the surface of the lower beam 14. The lifting cylinder 93 drives the movable locking heads 92 to move up and down in the vertical direction. The top of the movable locking head 92 is recessed with a groove 921. When the worktable 2 returns to the working position on the lower beam 14, the movable locking head 92 sinks down, embedding the roller 94 on the worktable 2 into the groove 921 for locking and positioning. When changing the mold, the movable locking head 92 lifts the roller 94 to disengage from the groove 921, allowing the worktable 2 to slide back and forth on the guide rail 91.

[0116] The quick mold change device 9 of this application incorporates a movable locking head 92 that works in conjunction with a lifting cylinder 93 to enhance the mechanical locking function. After the worktable 2 returns to its original position, the retraction of the lifting cylinder 93 causes the rollers 94 of the moving worktable 2 to form a rigid engagement with the groove 921 of the movable locking head 92. Combined with the weight of the moving worktable 2, this achieves secure vertical positioning. This active locking mechanism effectively prevents mold displacement during operation, fundamentally ensuring processing accuracy and stability. Furthermore, this structure can be supplemented with horizontal limiting elements, such as positioning shafts, forming a multi-dimensional precision locking system that further improves the locking effect.

[0117] In some embodiments, the quick mold changing device 9 further includes a built-in transmission assembly 95 disposed within the worktable 2. The built-in transmission assembly 95 includes a drive motor 951, a drive gear 952, a driven gear 953, and a linkage shaft 954. The drive motor 951 is fixedly installed inside the worktable 2. The rollers 94 include at least two drive rollers. Both drive rollers and the driven gear 953 are sleeved on the linkage shaft 954. The drive gear 952 is sleeved on the power output end of the drive motor 951 and meshes with the driven gear 953. The drive motor 951 drives the two drive rollers to roll synchronously through the meshing of the two gears.

[0118] Alternatively / and the lifting cylinder 93 is a pneumatic cylinder or a hydraulic cylinder, the cylinder body of which is concealed on the lower beam 14, the piston rod of the lifting cylinder 93 faces upward, and the top end of the piston rod is connected to the movable locking head 92 in a transmission connection.

[0119] This application replaces the existing external and long-stroke telescopic push-die cylinder transmission method with a built-in transmission component. This transmission method changes the arrangement of the drive element along the movement direction to a compact cyclic or meshing transmission, significantly shortening the axial length of the device in the pushing direction. The overall structure is more compact, greatly reducing the requirements for installation space, making the mold changing device suitable for various space-constrained applications. In addition, the locking structure, such as the lifting cylinder 93, is also set to be concealed, making the entire quick mold changing device 9 more compact.

[0120] In some embodiments, the lower beam 14 is installed in a preset working pit 500, the surface of the lower beam 14 is basically flush with the horizontal ground, and the guide rail 91 extends from the surface of the lower beam 14 to the horizontal ground outside the lower beam 14, so that the workbench 2 slides horizontally back and forth on the ground along the length direction of the guide rail 91; the workbench 2 is also provided with a plate mold mounting T-slot and a pipe mold guide seat.

[0121] This application installs the lower beam 14 vertically downwards and conceals it within the working pit 500. The workbench 2, which concentrates processing actions, and the mold changing structure are set on a horizontal surface, which facilitates manual observation of the working conditions and quick mold changes, thereby improving production switchover efficiency.

[0122] Furthermore, the tube sheet composite forming device 100 also includes a water circulation system 10, which includes a perimeter water tank 101, a pre-storage water tank 102, and a transition water tank 103 surrounding the workbench 2. The surface of the workbench 2 is provided with multiple drainage channels 21, and each drainage channel 21 eventually flows from the surrounding outlets to the perimeter water tank 101. The perimeter water tank 101 is connected to the pre-storage water tank 102 through a first pipe 104. The liquid in the pre-storage water tank 102 is directly connected to the mold located on the workbench 2 through a second pipe 105 or pressurized by a booster 109 and then connected to the mold through a third pipe 106. The transition water tank 103 is connected to the mold through a fourth pipe 107 to output a temporary water source. The transition water tank 103 is directly connected to a tap water pipe or connected to the pre-storage water tank 102 through a fifth pipe 108 to replenish the return water source.

[0123] The pre-stored water tank 102 is divided into a first water tank 1021 and a second water tank 1022 by a partition plate. The first water tank 1021 is used to collect the liquid discharged from each mold, and the second water tank 1022 is connected to the booster 109. The first water tank 1021 is divided into multiple chambers 1021a, and each chamber 1021a is equipped with a filter purifier 1021b. The water after multi-stage purification flows to the second water tank 1022 by a water pump. The infusion device 400 of this application can directly use the liquid from the pre-stored water tank.

[0124] To address the issue of water system adaptability under various operating conditions, this application establishes a perimeter water tank 101, a pre-storage water tank 102, a transition water tank 103, and their respective water system connections. Specifically, the pre-storage water tank 102 is directly connected to the mold via the second pipe 105 for the liquid filling forming process, and the pre-storage water tank 102 is connected to the third pipe 106 and the booster 109 for the internal high-pressure forming process. Combined with the automatic switching of conventional control valves, this allows for simultaneous support of two completely different process requirements—internal high-pressure forming and liquid filling forming—within a single water system. The equipment can quickly switch operating modes without modification, greatly improving its versatility and utilization. Furthermore, this application adds the perimeter water tank 101 and the first pipe 104 as a return water path. After the molding process is completed, the waste liquid is no longer discharged directly. Instead, it is collected through the surrounding water tank 101 and then returned to the pre-storage water tank 102 through the first pipe 104, realizing the recycling of water. This greatly saves production water, reduces operating costs, and is in line with the development direction of green manufacturing.

[0125] Example 2

[0126] The present invention also provides a control method for the compact tube sheet composite forming hydraulic system of Embodiment 1, comprising the following steps:

[0127] The system receives the processing mode selected by the user, which includes the high-pressure forming mode inside the pipe, the liquid-filled deep drawing mode of the sheet metal, and the forward and reverse deep drawing forming mode of the sheet metal without liquid medium.

[0128] Based on the user's selected mode, the CNC system retrieves the corresponding process path parameters from the pre-stored process database: When the user selects the high-pressure forming mode inside the pipe, the CNC system retrieves the process parameters corresponding to the current pipe material, diameter, and wall thickness from the pre-stored high-pressure forming process database inside the pipe, including the internal pressure curve, axial feed force curve, and mold clamping force; when the user selects the liquid-filled deep drawing mode for sheet metal, the CNC system retrieves the process parameters corresponding to the current sheet metal material and thickness from the pre-stored liquid-filled deep drawing process database for sheet metal, including the blank holder force curve, mold liquid chamber pressure curve, and the downward speed and pressure curve of the upper composite cylinder; when the user selects the liquid-free deep drawing forming mode for sheet metal, the CNC system retrieves the process parameters corresponding to the current sheet metal material and thickness from the pre-stored liquid-free deep drawing forming process database for sheet metal, including the blank holder force curve and the downward speed and pressure curve of the upper composite cylinder.

[0129] Based on the process path parameters, the CNC system controls the hydraulic device and the fluid delivery device to work together to complete the forming of the corresponding pipe or plate.

[0130] Specifically, the control process for each working mode is as follows:

[0131] When the user selects the internal high-pressure forming mode, the lower mold of the internal high-pressure mold G1 containing the pipe fitting is fixedly installed on the worktable 2. The CNC system locks the middle beam 13 and the mold pad 15 to form a one-piece movable beam. The upper mold of the internal high-pressure mold is fixedly installed on the one-piece movable beam. The upper composite cylinder 31 drives the one-piece movable beam to move down synchronously. The upper mold moves down and closes with the lower mold, providing a mold closing force not less than the mold opening force generated by the highest pressure inside the pipe. Then, the horizontal hydraulic devices 4 on the left and right sides feed axially towards the center of the pipe fitting. The plugs at the ends of the horizontal hydraulic devices 4 press the two ends of the pipe blank to form a high-pressure seal. The liquid delivery device injects low-pressure liquid into the pipe blank and pipe fitting. The CNC system raises the pressure of the liquid inside the pipe to the ultra-high pressure setting value according to the pressure curve inside the pipe. At the same time, it controls the horizontal hydraulic devices 4 on both sides to perform axial feeding according to the axial feed force curve, so that the pipe wall expands outward under the action of internal pressure and fits the mold cavity, completing the internal high-pressure forming of the pipe fitting. After processing, the horizontal hydraulic devices 4 retract horizontally between the adjacent tie rods, waiting for the start of the next working mode.

[0132] When the user selects the liquid-filled deep drawing mode, the lower die of the liquid-filled drawing die containing the sheet metal is fixedly installed on the worktable 2, and the upper die of the liquid-filled drawing die is fixedly installed on the die pad 15. The CNC system unlocks the middle beam 13 from the die pad 15, and the middle beam 13 and the die pad 15 move up and down respectively under the drive of the primary cylinder 311 and the secondary cylinder 312. The secondary cylinder 312 drives the die pad 15 and the upper die to move down until they contact the sheet metal and then temporarily stop. At the same time, the primary cylinder 311 drives the middle beam 13 to move down, pressing the edge of the sheet metal against the lower die. The blank holder pressure is provided, and the initial blank holder force is established according to the blank holder force curve. The liquid infusion device is activated to quickly fill the mold, injecting liquid medium into the mold chamber of the liquid-filling stretching die. The mold chamber pressure rises according to the preset mold chamber pressure curve. According to the preset downward speed and pressure curve of the upper composite cylinder, the upper die continues to descend to pull the sheet into the lower die. The CNC system collects feedback signals of mold chamber pressure and displacement signals in real time, so that the sheet is formed by the mold under hydraulic action. The mold chamber pressure rises to the highest set value and is held for a preset time to ensure that the sheet is fully attached to the mold, completing the liquid-filling deep drawing of the sheet.

[0133] When the user selects the liquid-free deep drawing forming mode, the lower die of the liquid-free stretching die G2 containing the sheet metal is fixedly installed on the worktable 2, and the upper die of the liquid-free stretching die is fixedly installed on the die pad 15. The CNC system unlocks the middle beam 13 from the die pad 15. The middle beam 13 and the die pad 15 move up and down respectively under the drive of the first-stage cylinder 311 and the second-stage cylinder 312. The second-stage cylinder 312 drives the die pad 15 and the upper die to move down until they contact the sheet metal and then temporarily stop. At the same time, the first-stage cylinder 311 drives the middle beam 13 down to press the edge of the sheet metal against the lower die to provide pressure for the blank holder ring. The initial blank holder force is established according to the blank holder force curve. According to the preset downward speed and pressure curve of the upper composite cylinder, the upper die continues to move down to pull the sheet metal into the lower die. The CNC system collects feedback signals of the pressure and displacement signals of the mold fluid chamber in real time, so that the sheet metal is formed by adhering to the mold under hydraulic action. The pressure of the mold fluid chamber rises to the highest set value and is held for a preset time to ensure that the sheet metal is fully adhered to the mold, thus completing the liquid-free deep drawing forming of the sheet metal. The difference between medium-free stretching dies and liquid-filled stretching dies lies in the absence of a liquid injection port and a liquid chamber.

[0134] When switching between the above processing modes, the corresponding mold must be replaced. In this embodiment, the mold replacement is achieved using the quick mold changing device 9 described in Embodiment 1. For the specific structure and operation process, please refer to Embodiment 1, which will not be repeated here.

[0135] In all the aforementioned modes, the vertical hydraulic device 3 and horizontal hydraulic device 4 on the shared workstation 100G are rationally designed in terms of spatial positioning, reflecting the efficiency improvement in completing multiple working modes. In particular, the design of the upper composite cylinder 31 and lower cylinder assembly 32 of the vertical hydraulic device 3, with its connection and locking cylinder 5 on the tube sheet composite forming device, allows the upper composite cylinder 31 to cooperate with the middle beam 13 and the mold pad 15 in various motion modes without spatial interference. Similarly, the lower cylinder assembly 32, pre-embedded within the lower beam 14 and designed with partitioned and independently controlled sections, also ensures that multiple motion modes can be coordinated without spatial interference.

[0136] In addition, an external robotic arm (not shown in the figure) can be added according to the processing requirements of the formed workpiece to solve the needs of replacing parts or special transfer. The robotic arm is set outside the machine body and operates through the spatial position between each prestressed tie rod 111.

[0137] As a further preferred embodiment, when switching processing modes, the method further includes: the CNC system automatically detects the current mold and the tooling status assembled with the worktable 2; when mold replacement is required, the CNC system detects that the middle beam 13 is locked onto the tie rod assembly 11 by a safety component, ensuring that the safety conditions for mold replacement are met, and then the robot or manual replacement of the mold is performed; after the mold replacement is completed, the CNC system automatically completes the reset of the two sets of hydraulic devices and the reconfiguration of the process path parameters. In this embodiment, the safety component is implemented using the safety cylinder assembly 6 described in Embodiment 1; the specific structure and operation process are described in Embodiment 1 and will not be repeated here.

[0138] This application breaks down the technical barriers between tubular and plate hydraulic forming devices through structural integration and improvement, providing the market with an efficient and flexible tubular-plate composite forming solution with significant technological advancements and industrial application value.

[0139] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A compact tubular sheet composite forming hydraulic system, characterized in that, include: A tube-plate composite forming device includes a machine body and a worktable. The machine body is a closed frame structure, and the worktable is set inside the closed frame structure. The worktable has a common station for tube forming and plate forming. Two sets of hydraulic devices, namely a vertical hydraulic device and a horizontal hydraulic device, are provided. The vertical hydraulic device is set in the vertical direction of the closed frame structure and is used to apply vertical pressure to the mold. The horizontal hydraulic device is set in the horizontal direction of the closed frame structure and is used to apply horizontal pressure to the mold. The numerical control system is electrically connected to the hydraulic device and the fluid delivery device, respectively; When processing pipe fittings, the mold containing the pipe fittings is installed on a common station. The CNC system controls the vertical hydraulic device and the horizontal hydraulic device to apply pressure to the mold and inject liquid into the center of the pipe fitting, so that the pipe wall expands outward to fit the mold cavity and completes the pipe forming. When processing sheet metal, the mold containing the sheet metal is installed in a common workstation. The CNC system controls the vertical hydraulic device to apply pressure to the mold, so that the sheet metal and the mold cavity are fully fitted together, and the sheet metal is formed.

2. The compact tube sheet composite forming hydraulic system as described in claim 1, characterized in that, The machine body includes a tie rod assembly, an upper beam, a middle beam, a lower beam, and a mold pad. The tie rod assembly adopts a column-type pre-tightened tie rod structure and is set between the upper beam and the lower beam. Its two ends are fastened to the upper beam and the lower beam respectively through pre-tightening cylinders to form a closed frame structure. The vertical hydraulic device includes an upper composite cylinder and a lower cylinder assembly. The upper composite cylinder is a multi-stage piston cylinder, which is fixed to the upper beam. Its power output end is connected to the middle beam and the mold pad respectively. The mold pad is movably inserted inside the middle beam. The middle beam and the mold pad move up and down independently or move up and down synchronously under the drive of the upper composite cylinder. The lower cylinder assembly is located inside the lower beam, and the worktable is located on the surface of the lower beam. The power output end of the lower cylinder assembly is connected to two sets of ejector pins respectively. The two sets of ejector pins move up and down independently under the drive of the lower cylinder assembly. The horizontal hydraulic device is movably mounted on both sides of the worktable and located between adjacent tie rod assemblies.

3. The compact tube sheet composite forming hydraulic system as described in claim 2, characterized in that, The upper composite cylinder includes a primary cylinder and a secondary cylinder disposed inside the primary cylinder. The primary cylinder includes a primary cylinder barrel, and a secondary cylinder barrel is fixedly disposed inside the primary cylinder barrel. A primary cylinder piston rod is movably nested between the inner wall of the primary cylinder barrel and the outer wall of the secondary cylinder barrel. A secondary cylinder piston rod is movably nested inside the secondary cylinder barrel. The primary cylinder piston rod is fixedly connected to the middle beam, driving the middle beam to move up and down in the vertical direction. The secondary cylinder piston rod is fixedly connected to the mold pad, driving the mold pad to move up and down in the vertical direction. The second-stage cylinder barrel is fixedly provided with a second-stage cylinder quick rod at the top end, and the end of the second-stage cylinder quick rod passes through the piston rod of the second-stage cylinder. The second-stage cylinder quick rod has an oil inlet and outlet chamber. The second-stage cylinder barrel is also provided with a displacement sensor and an anti-rotation rod to prevent the displacement sensor from axially shifting. The ends of the displacement sensor and the anti-rotation rod both pass through the piston rod of the second-stage cylinder.

4. The compact tube sheet composite forming hydraulic system as described in claim 2, characterized in that, The tube sheet composite forming device also includes a connecting locking cylinder disposed between the middle beam and the mold pad. The connecting locking cylinder is installed on the middle beam or the mold pad and is used to mechanically lock the middle beam and the mold pad or to loosen them when needed. The tube sheet composite forming device may also include at least one safety cylinder assembly, which is a hydraulic locking cylinder or a mechanical safety lock. The safety cylinder assembly is arranged in a horizontal direction, and the middle beam or the tie rod assembly is provided with a locking hole. The locking head of the safety cylinder assembly can extend into the locking hole.

5. The compact tube sheet composite forming hydraulic system as described in claim 2, characterized in that, The tube sheet composite forming device also includes an upper hydraulic cushion and a lower hydraulic cushion. The upper hydraulic cushion is located at the bottom of the middle beam, and the lower beam has a hollow structure in the middle. The lower hydraulic cushion is slidably installed in the hollow structure of the lower beam. Multiple vertically arranged hydraulic cushion top columns are provided in the hollow structure. Each hydraulic cushion top column passes through the lower hydraulic cushion. The bottom of the hydraulic cushion top column is fixedly connected to the lower beam, and the top of the hydraulic cushion top column supports the worktable. Multiple shock-absorbing rods are provided at the bottom of the lower hydraulic cushion according to the need for vertical pressure.

6. The compact tube sheet composite forming hydraulic system as described in claim 2, characterized in that, The tube sheet composite forming device also includes a quick mold changing device for rapidly changing different molds. This quick mold changing device includes a guide rail, a movable locking head, and a lifting cylinder. The guide rail is disposed on the surface of the lower beam and extends horizontally outward from the lower beam. Rollers are provided at the bottom of the worktable, and these rollers slide in cooperation with the guide rail, allowing the worktable to slide horizontally back and forth along the length of the guide rail. Each roller corresponds to a movable locking head and a lifting cylinder for locking and unlocking actions. Several movable locking heads are disposed on the guide rail located on the surface of the lower beam. The lifting cylinder drives the movable locking heads to move up and down vertically. A recessed groove is provided at the top of each movable locking head. When the worktable returns to its working position on the lower beam, the movable locking head sinks, embedding the rollers on the worktable into the recessed groove for locking and positioning. When changing molds, the movable locking head lifts the rollers, disengaging them from the recessed groove, allowing the worktable to slide back and forth on the guide rail.

7. The compact tube sheet composite forming hydraulic system as described in claim 2, characterized in that, The tube sheet composite forming device also includes a water circulation system, which includes a perimeter water tank, a pre-storage water tank, and a transition water tank surrounding the workbench. The workbench surface is provided with multiple drainage channels, and each drainage channel ultimately flows from the surrounding outlets to the perimeter water tank. The perimeter water tank is connected to the pre-storage water tank through a first pipe. The liquid in the pre-storage water tank is directly connected to the mold located on the workbench through a second pipe, or after being pressurized by a booster, it is connected to the mold through a third pipe. The transition water tank is connected to the mold through a fourth pipe to output a temporary water source. The transition water tank is directly connected to a tap water pipe, or it is connected to the pre-storage water tank through a fifth pipe to replenish the return water source. The pre-stored water tank is divided into a first water tank and a second water tank. The first water tank is used to recover the liquid discharged from each mold, and the second water tank is connected to the booster. The first water tank is divided into multiple chambers, and each chamber is equipped with a filter purifier. The water that has been purified through multiple stages flows to the second water tank.

8. A control method for the compact tube sheet composite forming hydraulic system according to any one of claims 3 to 7, characterized in that, Includes the following steps: The system receives the processing mode selected by the user, which includes the high-pressure forming mode inside the pipe, the liquid-filled deep drawing mode of the sheet metal, and the liquid-free deep drawing mode of the sheet metal. Based on the mode selected by the user, the CNC system retrieves the corresponding process path parameters from the pre-stored process database: when the user selects the high-pressure forming mode inside the pipe, the CNC system retrieves the process parameters corresponding to the current pipe material, diameter and wall thickness from the pre-stored high-pressure forming process database inside the pipe, including the internal pressure curve, axial feed force curve and mold clamping force. When the user selects the sheet metal filling and deep drawing mode, the CNC system retrieves the process parameters corresponding to the current sheet metal material and thickness from the pre-stored sheet metal filling and deep drawing process database, including the blank holder force curve, the mold liquid chamber pressure curve, and the downward speed and pressure curve of the upper composite cylinder. When the user selects the liquid-free deep drawing forming mode for sheet metal, the CNC system retrieves the process parameters corresponding to the current sheet metal material and thickness from the pre-stored liquid-free deep drawing forming process database, including the blank holder force curve, the downward speed and pressure curve of the upper composite cylinder; Based on the process path parameters, the CNC system controls the hydraulic device and the fluid delivery device to work together to complete the forming of the corresponding pipe or plate.

9. The control method as described in claim 8, characterized in that, When the user selects the internal high-pressure forming mode, the lower mold of the internal high-pressure mold containing the pipe fitting is fixedly installed on the worktable. The CNC system locks the middle beam and the mold pad to form a one-piece movable beam. The upper mold of the internal high-pressure mold is fixedly installed on the one-piece movable beam. The upper composite cylinder drives the one-piece movable beam to move down synchronously. The upper mold moves down and closes with the lower mold, providing a mold closing force not less than the mold opening force generated by the highest pressure inside the pipe. Then, the horizontal hydraulic devices on the left and right sides feed axially towards the center of the pipe fitting. The plugs at the ends of the horizontal hydraulic devices press the two ends of the pipe blank to form a high-pressure seal. The liquid delivery device injects low-pressure liquid into the pipe blank and pipe fitting. The CNC system raises the pressure of the liquid inside the pipe to the ultra-high pressure setting value according to the pressure curve inside the pipe. At the same time, it controls the horizontal hydraulic devices on both sides to perform axial feeding according to the axial feed force curve, so that the pipe wall expands outward under the action of internal pressure and fits the mold cavity, completing the internal high-pressure forming of the pipe fitting. When the user selects the liquid-filled deep drawing forming mode, the lower die of the liquid-filled stretching die containing the sheet metal is fixedly installed on the worktable, and the upper die of the liquid-filled stretching die is fixedly installed on the die pad. The CNC system unlocks the middle beam from the die pad, and the middle beam and die pad move up and down respectively under the drive of the first-stage cylinder and the second-stage cylinder. The second-stage cylinder drives the die pad and the upper die to move down until they contact the sheet metal and then stop temporarily. At the same time, the first-stage cylinder drives the middle beam to move down, pressing the edge of the sheet metal against the lower die to provide blank holder pressure, and the initial blank holder force is established according to the blank holder force curve. The infusion device is activated for rapid filling, injecting liquid medium into the mold liquid chamber of the filling stretching mold. The pressure in the mold liquid chamber rises according to the preset mold liquid chamber pressure curve. Based on the preset downward speed and pressure curve of the upper composite cylinder, the upper mold continues to descend to pull the plate into the lower mold. The CNC system collects feedback signals of mold liquid chamber pressure and displacement signals in real time, so that the plate is molded under hydraulic action. The pressure in the mold chamber rises to the highest set value and is held for a preset time to ensure that the sheet metal fully adheres to the mold, thus completing the sheet metal filling and deep drawing process. When the user selects the liquid-free deep drawing mode, the lower die of the liquid-free stretching die containing the sheet metal is fixedly installed on the worktable, and the upper die of the liquid-free stretching die is fixedly installed on the die pad. The CNC system unlocks the middle beam from the die pad, and the middle beam and die pad move up and down respectively under the drive of the first-stage cylinder and the second-stage cylinder. The second-stage cylinder drives the die pad and the upper die to move down until they contact the sheet metal and then stop temporarily. At the same time, the first-stage cylinder drives the middle beam down to press the edge of the sheet metal against the lower die to provide pressure for the blank holder ring, and establishes the initial blank holder force according to the blank holder force curve. According to the preset downward speed and pressure curve of the upper composite cylinder, the upper die continues to move down to pull the sheet metal into the lower die. The CNC system collects feedback signals of the mold fluid chamber pressure and displacement signals in real time, so that the sheet metal is formed by hydraulic action. The mold fluid chamber pressure rises to the highest set value and is held for a preset time to ensure that the sheet metal is fully attached to the die, thus completing the liquid-free deep drawing of the sheet metal. When switching between the above processing modes, the corresponding mold must be replaced.

10. The control method as described in claim 9, characterized in that, When switching processing modes, the method further includes: the CNC system detects that the beam is locked onto the tie rod assembly by a safety component, and after ensuring that the safety conditions for mold replacement are met, the robot or a person replaces the mold.

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