A press-bulging forming system

Abstract

The present invention relates to a press-bulging forming system, which includes a hydraulic press. The hydraulic press includes an upper crossbeam, an intermediate movable beam and a workbench. The intermediate movable beam can move in a direction towards or away from the workbench. The system further includes a boosting system, which includes one or more cylinders. Each cylinder includes a cylinder body, a piston disposed in the cylinder body, and a piston rod with one end extending out of the cylinder body. The cylinder body is mounted on the workbench, and the end of the piston rod extending out of the cylinder body is connected to the intermediate movable beam. The cylinder body is provided with a low-pressure gas inlet and a high-pressure gas outlet. By using the downward pressing action of the intermediate movable beam, the present invention can not only provide a die closing pressure for the pipe to be bulged, but also compress the gas in the cylinder to provide high-pressure gas for the bulging of the pipe. The present invention makes full use of the surplus pressure of the press, saves costs, and is particularly suitable for providing internal pressure for the press-bulging forming of metal pipes with low deformation resistance.

Description

Technical Field

[0001] The present invention relates to a press-bulging forming system, belonging to the technical field of hydroforming presses. Background Art

[0002] Tube parts, especially high-strength steel tube parts, are widely used in the field of automotive parts due to their high bending strength, high torsional stiffness, etc. Usually, such parts are manufactured by hydroforming technology. In this technology, the deformation resistance of the tube is large in the cold state, and the internal pressure of the tube needs to reach several hundred megapascals to be fully formed, which requires extremely high requirements for the hydraulic system. In addition, the strength of hydroformed parts is not high and it is difficult to exceed 1000 megapascals. The hot metal bulging technology is an internal high-pressure forming technology developed in recent years for high-strength steel tube parts. In this technology, the high-strength steel tube blank is first heated to 880°C - 950°C to completely austenitize the inside of the tube blank, and then the tube blank is transferred to the forming die. The inside of the tube blank is inflated, the die is pressed and quenched, and the final strength of the tube part reaches 1500 megapascals. This technology has great advantages for realizing high-strength, variable cross-section, and variable curvature closed-section parts. However, this technology requires providing high-pressure gas of more than 10 megapascals inside the tube. For shapes with relatively small local fillets, even dozens of megapascals of internal pressure gas are required, and it needs to be pressurized twice or even three times to reach. At present, since the gas pressurization system adopted by the hot metal bulging technology includes compressors, gas storage devices, standby compressors, etc., the equipment cost is as high as more than one million.

[0003] Therefore, in order to obtain high-strength, variable cross-section, and variable curvature closed-section parts at a low cost, it is urgent to develop a low-cost press-bulging forming system. Summary of the Invention

[0004] The purpose of the present invention is to provide a new technical solution to improve or solve the technical problems existing in the above-mentioned prior art.

[0005] The technical solution provided by the present invention is as follows: A press-bulging forming system includes a hydraulic press. The hydraulic press includes an upper crossbeam, an intermediate movable beam, and a workbench. The intermediate movable beam can move in a direction towards or away from the workbench. It further includes a pressurization system. The pressurization system includes one or more cylinders. Each cylinder includes a cylinder body, a piston disposed inside the cylinder body, and a piston rod with one end extending out of the cylinder body. The cylinder body is installed on the workbench, and the end of the piston rod extending out of the cylinder body is connected to the intermediate movable beam. The cylinder body is provided with a low-pressure gas inlet and a high-pressure gas outlet.

[0006] The technical solution provided by the present invention has the following beneficial effects compared with the prior art: By utilizing the downward pressure of the intermediate movable beam, the present invention can not only provide a die-closing pressure for the pipe fitting to be expanded, but also compress the gas in the cylinder to provide high-pressure gas for the expansion of the pipe fitting. The present invention makes full use of the surplus pressure of the press, saves costs, has a simple structure, and does not require additional investment, and is particularly suitable for providing internal pressure for the hydro-bulging forming of metal pipes with low deformation resistance.

[0007] On the basis of the above technical solution, the present invention can be further improved as follows.

[0008] Furthermore, it further includes a bulging die. The upper die of the bulging die is installed on the intermediate movable beam, and the lower die of the bulging die is installed on the workbench. After the upper die and the lower die are buckled, a forming cavity for accommodating the pipe fitting to be expanded is formed, and a high-pressure gas outlet pipe is externally connected to the high-pressure gas outlet.

[0009] The beneficial effect of adopting the above further solution is that the high-pressure gas outlet pipe is used to communicate with the pipe fitting to be expanded installed in the forming cavity.

[0010] Furthermore, the boosting system further includes a height adjusting device, and the cylinder is installed on the workbench through the height adjusting device.

[0011] The beneficial effect of adopting the above further solution is that by adjusting the height of the cylinder through the height adjusting device, the present invention can also output multiple levels of pressure to meet the process requirements of pipe fitting expansion.

[0012] Furthermore, the boosting system further includes a low-pressure gas source device, and the low-pressure gas source device is communicated with the low-pressure gas inlet through a low-pressure gas inlet pipe.

[0013] Furthermore, it further includes a die water cooling system, and the die water cooling system is communicated with the forming cavity through a coolant pipe.

[0014] The beneficial effect of adopting the above further solution is that it is used to introduce coolant into the forming cavity, and the pipe fitting can be quickly cooled after expansion, improving the expansion efficiency.

[0015] Furthermore, feed stoppers are provided on both sides of the bulging die, and the feed stoppers can move horizontally.

[0016] Furthermore, a one-way valve is provided at the low-pressure gas inlet.

[0017] Furthermore, an intake pressure gauge is provided on the low-pressure gas inlet pipe.

[0018] Furthermore, a pressure relief valve is provided on the high-pressure gas outlet pipe.

[0019] Further, an outlet pressure gauge is provided between the pressure relief valve and the high-pressure gas outlet. Description of the Drawings

[0020] Figure 1 is a schematic structural diagram of the press-bulging forming system of the present invention;

[0021] In the figure, 1, low-pressure gas source device; 2, one-way valve; 3, intake pressure gauge; 4, gas flow meter; 5, flow control valve; 6, low-pressure charging pipe; 7, high-pressure charging pipe; 8, cylinder; 9, bulging die; 10, feed stop; 11, sealing head; 12, height adjustment device; 13, pressure relief valve; 14, outlet pressure gauge; 15, upper crossbeam; 16, water cooling system; 17, intermediate movable beam; 18, workbench. Specific Embodiments

[0022] The principles and features of the present invention will be described below in conjunction with examples. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0023] As Figure 1 shown, a press-bulging forming system includes a hydraulic press. The hydraulic press includes an upper crossbeam 15, an intermediate movable beam 17, and a workbench 18. The intermediate movable beam 17 can move towards or away from the workbench 18. The system further includes a boosting system. The boosting system includes one or more cylinders 8. Each cylinder 8 includes a cylinder body, a piston disposed in the cylinder body, and a piston rod with one end extending out of the cylinder body. The cylinder body is installed on the workbench 18, and the end of the piston rod extending out of the cylinder body is connected to the intermediate movable beam 17. The cylinder body is provided with a low-pressure gas inlet and a high-pressure gas outlet.

[0024] The piston divides the inner cavity of the cylinder body into an upper cavity and a lower cavity. The cylinder body is provided with a low-pressure gas inlet and a high-pressure gas outlet, and both the low-pressure gas inlet and the high-pressure gas outlet communicate with the lower cavity.

[0025] In addition, in this embodiment,

[0026] the press-bulging forming system further includes a bulging die 9. An upper die of the bulging die 9 is installed on the intermediate movable beam 17, and a lower die of the bulging die 9 is installed on the workbench 18. After the upper die and the lower die are buckled, a forming cavity for accommodating the pipe to be bulged is formed. The high-pressure gas outlet is externally connected to a high-pressure charging pipe 7, and the high-pressure charging pipe 7 is used to communicate with the pipe to be bulged installed in the forming cavity. Both ends of the pipe to be bulged are blocked by a sealing head 11, and the sealing head 11 is provided with a through hole connected to the high-pressure charging pipe 7.

[0027] The supercharging system further includes a height adjusting device 12, and the cylinder 8 is mounted on the workbench 18 through the height adjusting device 12. During the tube expansion process, it is not possible to fill the tube with gas at too high a pressure all at once. It is necessary to provide gas at different pressures to the tube in stages to ensure the quality of tube expansion. The height adjusting device 12 can adjust the height of the cylinder 8, and by adjusting the height of the cylinder 8, the output of gas at different pressures can be achieved, and multi-stage pressures can be provided to the tube in stages during the tube expansion process. The height adjusting device 12 described in the present invention can directly adopt existing devices that can realize the height adjustment function of the cylinder 8, such as a hydraulic height adjusting frame, a pneumatic height adjusting frame, an electric height adjusting frame, etc.

[0028] The supercharging system further includes a low-pressure gas source device 1, and the low-pressure gas source device 1 is connected to the low-pressure gas inlet of the supercharging system through a low-pressure charging pipe 6.

[0029] The press-blow forming system further includes a die water cooling system 16, and the die water cooling system 16 is connected to the forming cavity through a coolant pipe. After the tube is expanded, the die water cooling system 16 is opened to introduce coolant into the forming cavity, which can quickly cool the expanded tube and improve the processing efficiency.

[0030] Feeding stoppers 10 are further provided on both sides of the expansion die 9, and the feeding stoppers 10 can move horizontally. When the tube is being expanded, the tube material will flow towards both ends, driving the feeding stoppers 10 to move horizontally closer to the tube, and the feeding stoppers 10 push the tube material at both ends of the tube towards the middle, playing a role in feeding.

[0031] A one-way valve 2 is provided at the low-pressure gas inlet, a one-way valve 2 is provided at the outlet of the low-pressure gas source device 1, an intake pressure gauge 3, a gas flow meter 4 and a flow control valve 5 are provided on the low-pressure charging pipe 6, a pressure relief valve 13 is provided on the high-pressure charging pipe 7, and an outlet pressure gauge 14 is provided between the pressure relief valve 13 and the high-pressure gas outlet.

[0032] According to Boyle's law at a constant temperature of an ideal gas, at a constant temperature, the pressure of the low-pressure gas source is inversely proportional to the volume. In the present invention, low-pressure gas is input into the cylinder 8 through the low-pressure gas source device 1. The cylinders 8 are evenly distributed at the four corners of the workbench 18 surface, and the piston rods of the cylinders 8 are connected to the upper table surface of the press. When the press descends, the gas in the cylinder 8 is compressed, and the gas pressure increases. The increased gas pressure is monitored by a pressure gauge. After reaching the specified pressure, the one-way valve 2 on the high-pressure charging pipe 7 is controlled by the control system to open and output high-pressure gas to provide internal pressure for press-blow forming.

[0033] The working principle of the press-blow forming system described in the present invention is as follows:

[0034] One is low-pressure gas inflation. Utilize the existing low-pressure gas source device 1. For example, the intake pressure of the low-pressure gas source device 1 is 5 MPa, and inflate the cylinder 8 on the press table. Assume the inflated volume of the cylinder 8 is V.

[0035] The second is to prepare high-pressure gas. Start the hydraulic cylinder above the hydraulic press. The piston rod of the hydraulic cylinder drives the middle movable beam 17 to move downward, and compress the gas in the cylinder 8 through the piston. Assume that the volume of the gas after compression is one-sixth of the original, then the pressure of the compressed gas is 30 MPa.

[0036] The third is to output high-pressure gas. Control the one-way valve 2 to open by the control system, and output high-pressure gas into the cavity of the pipe fitting to be expanded in the forming cavity.

[0037] In particular, if gases with different pressures need to be output when the press moves downward, the control system opens the pressure relief valve 13 at the current pressure of the compressed gas, and immediately fills the pipe fitting with compressed gas at the current pressure value. When expanding a specific part, multi-stage pressures need to be output in coordination with the die closing height. For example, when the middle movable beam 17 moves downward to half of its stroke position, gas with a pressure of P1 needs to be filled into the pipe fitting first. Then, adjust the height of the cylinder 8 through the cylinder 8 height adjustment device 12 so that when the press moves downward to half of its stroke position, the pressure of the compressed gas in the cylinder 8 is exactly P1. At this time, open the pressure relief valve 13 to fill the pipe fitting with gas. The middle movable beam 17 continues to move downward, and cooperate with the height adjustment device 12 to raise and adjust the height of the cylinder 8. The gas in the cylinder 8 continues to be compressed. When the pressure in the cylinder 8 reaches P2, gas with a pressure of P2 can be filled into the pipe fitting. During this process, if the outlet pressure gauge 14 detects that the gas pressure in the cylinder 8 is lower or higher than the required pressure for pipe fitting expansion forming, the control system will first close the pressure relief valve 13, and then open the pressure relief valve 13 when the required pressure is reached. Therefore, gases with different pressures can be output at different times as needed to meet the multi-stage pressurization requirements set by the part production process.

[0038] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A hydro-expansion forming system, comprising a hydraulic press, the hydraulic press including an upper crossbeam (15), an intermediate movable beam (17) and a workbench (18), the intermediate movable beam (17) being capable of moving in a direction towards or away from the workbench (18), characterized in that, It further includes a supercharging system, the supercharging system includes one or more cylinders (8), the cylinder (8) includes a cylinder block, a piston disposed within the cylinder block, and a piston rod with one end extending out of the cylinder block, the cylinder block is mounted on a workbench (18), and the end of the piston rod extending out of the cylinder block is connected to the intermediate movable beam (17), and a low-pressure gas inlet and a high-pressure gas outlet are provided on the cylinder block; It further includes a bulging die (9), an upper die of the bulging die (9) is mounted on the intermediate movable beam (17), a lower die of the bulging die (9) is mounted on the workbench (18), and a forming cavity for accommodating the to-be-bulged pipe fitting is formed after the upper die and the lower die are buckled, and a high-pressure charging pipe (7) is externally connected to the high-pressure gas outlet; The supercharging system further includes a height adjusting device (12), and the cylinder (8) is mounted on the workbench (18) through the height adjusting device (12); The supercharging system further includes a low-pressure air source device (1), and the low-pressure air source device (1) is communicated with the low-pressure gas inlet through a low-pressure charging pipe (6); A pressure relief valve (13) is provided on the high-pressure charging pipe (7).

2. The hydro-expansion forming system according to claim 1, characterized in that, It further includes a die water cooling system (16), and the die water cooling system (16) is communicated with the forming cavity through a coolant pipeline.

3. The hydro-expansion forming system according to claim 1, characterized in that, Feeding stoppers (10) are further provided on both sides of the bulging die (9), and the feeding stoppers (10) can move transversely.

4. The hydro-expansion forming system according to claim 1, characterized in that, A one-way valve (2) is provided at the low-pressure gas inlet.

5. The hydro-expansion forming system according to claim 1, characterized in that, An intake pressure gauge (3) is provided on the low-pressure charging pipe (6).

6. The hydro-expansion forming system according to claim 1, characterized in that, An outlet pressure gauge (14) is provided between the pressure relief valve (13) and the high-pressure gas outlet.

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