An EDT rolling hydraulic system

Abstract

The application provides an EDT rolling hydraulic system and relates to the technical field of sheet metal rolling mills. The EDT rolling hydraulic system comprises a hydraulic cylinder, the hydraulic cylinder comprises a cylinder body, a cylinder plug located in the cylinder body and a cylinder rod, the cylinder body comprises a first cylinder wall and a second cylinder wall in the axial direction, the cylinder rod is in sliding fit with the second cylinder wall along the axis of the cylinder body, and at least two cylinder plugs are sleeved on the cylinder rod. The cavity between the first cylinder wall and the cylinder plug close to the first cylinder wall is a positive pressure cavity, the cavity between the two cylinder plugs is a primary back pressure cavity, and the cavity between the second cylinder wall and the cylinder plug close to the second cylinder wall is a secondary back pressure cavity. The distribution of the positive pressure cavity, the primary back pressure cavity and the secondary back pressure cavity is formed in the cylinder body, the working area of the back pressure cavity is increased, small rolling force output can be realized under the condition that the positive rolling force is unchanged, and then the accurate control of EDT rolling is realized without affecting the conventional cold rolling control precision.

Description

Technical Field

[0001] This invention relates to the field of sheet metal rolling mill technology, and more specifically, to an EDT rolling hydraulic system. Background Technology

[0002] To ensure the surface properties of aluminum alloy automotive sheets and meet the needs of automobile manufacturing, while simplifying the production process and balancing efficiency and cost, single-stand cold rolling mills for aluminum alloy automotive sheets are generally required to have EDT rolling function, which means applying a small rolling force to roughen the surface of the strip.

[0003] Under conventional cold rolling conditions, the maximum rolling force output by the mill's hydraulic cylinder can reach 32,000 kN. However, in EDT mode, the minimum rolling force required by the hydraulic cylinder is only 800 kN, resulting in a very wide range of rolling force output by the AGC cylinder. When using traditional AGC cylinders and their matching hydraulic control systems, when a large rolling force is required, the load on the AGC cylinder is large, the pressure difference across the servo valve in the hydraulic control system is appropriate, and the valve core opening range of the servo valve can be controlled within its optimal performance range. However, during EDT rolling, the mill operates in a constant pressure control mode for leveling. If the rolling force is too small, the working pressure difference across the servo valve is too large, causing the servo valve core to operate in a non-optimal control range. This leads to a significant decrease in the response characteristics and control accuracy of the AGC control system, resulting in lower rolling quality. Summary of the Invention

[0004] The problem addressed by this invention is: how to avoid a significant drop in the performance parameters of the AGC control system, such as response characteristics and control accuracy, in EDT mode, so as to improve rolling quality.

[0005] To address the aforementioned problems, this invention provides an EDT rolling hydraulic system, comprising a hydraulic cylinder. The hydraulic cylinder includes a cylinder body, cylinder plugs located within the cylinder body, and cylinder rods. The cylinder body includes a first cylinder wall and a second cylinder wall located axially thereon. The cylinder rods slide against the second cylinder wall along the axis of the cylinder body. At least two cylinder plugs are sleeved on the cylinder rods. The cavity between the first cylinder wall and the cylinder plug near the first cylinder wall is a positive pressure cavity, the cavity between the two cylinder plugs is a primary back pressure cavity, and the cavity between the second cylinder wall and the cylinder plug near the second cylinder wall is a secondary back pressure cavity.

[0006] Optionally, the EDT rolling hydraulic system further includes a positive pressure control link, which includes a positive pressure solenoid directional valve, a positive pressure servo valve, a first positive pressure hydraulically controlled check valve, and a second positive pressure hydraulically controlled check valve. One end of the positive pressure solenoid directional valve is connected to the control port X of the first positive pressure hydraulically controlled check valve and the second positive pressure hydraulically controlled check valve, respectively. The other two ends of the positive pressure solenoid directional valve are respectively connected to the system supply oil pipe P and the system return oil pipe T. One end of the first positive pressure hydraulically controlled check valve is connected to the port A of the positive pressure servo valve, and the other end is connected to the positive pressure chamber. The control port Y of the first positive pressure hydraulically controlled check valve is connected to the system drain oil pipe Y. One end of the second positive pressure hydraulically controlled check valve is connected to the port P of the positive pressure servo valve, and the control port Y of the second positive pressure hydraulically controlled check valve is connected to the system drain oil pipe Y. The port T of the positive pressure servo valve is connected to the system return oil pipe T.

[0007] Optionally, the positive pressure control link further includes a first pressure sensor connected to the cylinder body, the first pressure sensor being used to detect the pressure of the positive pressure chamber and communicating with the positive pressure servo valve.

[0008] Optionally, the positive pressure control link further includes a displacement sensor connected to the cylinder body, the displacement sensor being used to detect the movement distance of the cylinder rod and communicating with the positive pressure servo valve.

[0009] Optionally, the hydraulic cylinder further includes two proximity switches connected to the cylinder body. The two proximity switches are used to provide feedback on the extreme positions of a single cylinder piston and are communicatively connected to the positive pressure servo valve.

[0010] Optionally, the positive pressure control link further includes a positive pressure solenoid relief valve, which is used to connect the positive pressure chamber and the system return oil T-pipe.

[0011] Optionally, the positive pressure control link further includes a positive pressure check valve, which is connected between the positive pressure servo valve and the system return oil T-pipe.

[0012] Optionally, the EDT rolling hydraulic system further includes a back pressure control link, which includes a three-way proportional pressure reducing valve. One end of the three-way proportional pressure reducing valve is connected to the first-stage back pressure chamber and the second-stage back pressure chamber, respectively. The other three ports of the three-way proportional pressure reducing valve are connected to the system oil supply P pipe, the system oil return T pipe, and the system oil drain Y pipe, respectively. Alternatively, the back pressure control link includes a back pressure solenoid directional valve, a back pressure servo valve, a first back pressure hydraulic control check valve, and a second back pressure hydraulic control check valve. One end of the back pressure solenoid directional valve is connected to the control port X of both the first and second back pressure hydraulic control check valves, and the other two ends are connected to the system supply oil pipe P and the system return oil pipe T, respectively. One end of the first back pressure hydraulic control check valve is connected to the A port of the back pressure servo valve, and the other end is connected to the first-stage back pressure chamber and the second-stage back pressure chamber, respectively. The Y port of the back pressure hydraulic control check valve is connected to the system drain oil pipe Y. One end of the second back pressure hydraulic control check valve is connected to the P port of the back pressure servo valve, and the other end is connected to the system supply oil pipe P. The Y port of the second back pressure hydraulic control check valve is connected to the system drain oil pipe Y. The T port of the back pressure servo valve is connected to the system return oil pipe T through the back pressure return oil check valve.

[0013] Optionally, when the back pressure control link includes a three-way proportional pressure reducing valve, the back pressure control link further includes a back pressure relief valve, one end of which is connected to the first-stage back pressure chamber and the second-stage back pressure chamber respectively, and the other end is connected to the system return oil T-pipe; or, when the back pressure control link includes a back pressure solenoid directional valve, the back pressure control link further includes a back pressure solenoid relief valve, one end of which is connected to the first-stage back pressure chamber and the second-stage back pressure chamber respectively, and the other end is connected to the system return oil T-pipe.

[0014] Optionally, the back pressure control link further includes a second pressure sensor, which is used to detect the pressure of the first-stage back pressure chamber and the second-stage back pressure chamber. When the back pressure control link includes a three-way proportional pressure reducing valve, the second pressure sensor is communicatively connected to the three-way proportional pressure reducing valve; or, when the back pressure control link includes the back pressure servo valve, the second pressure sensor is communicatively connected to the back pressure servo valve.

[0015] Compared with related technologies, the EDT rolling hydraulic system of the present invention uses a cylinder rod that slides along the axis of the cylinder body and engages with the second cylinder wall, with at least two cylinder plugs sleeved on the cylinder rod. The movement of the cylinder rod is converted into the movement of the two cylinder plugs. In the direction of movement of the two cylinder plugs, the cavity between the first cylinder wall and the cylinder plug near the first cylinder wall is a positive pressure cavity, and the cavity between the two cylinder plugs is a primary back pressure cavity. The cavity between the second cylinder wall and the cylinder plug near the second cylinder wall is a secondary back pressure cavity. This creates a distribution of positive pressure cavity, primary back pressure cavity, and secondary back pressure cavity inside the cylinder body, increasing the working area of ​​the back pressure cavity. This allows for more effective use of back pressure to offset part of the rolling force during EDT rolling, enabling the output of small rolling force while keeping the forward rolling force constant. Thus, precise control of EDT rolling is achieved without affecting the control accuracy of conventional cold rolling. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the hydraulic cylinder in an embodiment of the present invention; Figure 2 This is a schematic diagram of the hydraulic link structure of the EDT rolling hydraulic system in an embodiment of the present invention; Figure 3 This is a schematic diagram of another hydraulic link in the EDT rolling hydraulic system of this invention.

[0017] Explanation of reference numerals in the attached figures: 100 - Hydraulic cylinder; 110 - Cylinder body; 111 - First cylinder wall; 112 - Second cylinder wall; 120 - Cylinder plug; 130 - Cylinder rod; 200 - Positive pressure control link; 210 - Positive pressure solenoid directional valve; 220 - Positive pressure servo valve; 230 - First positive pressure hydraulic check valve; 240 - Second positive pressure hydraulic check valve; 250 - First pressure sensor; 260 - Displacement sensor; 270 - Proximity switch; 280 - Positive pressure solenoid relief valve; 290 - Positive pressure check valve; 300 - Back pressure control link; 310 - Three-way proportional pressure reducing valve; 320 - Back pressure solenoid directional valve; 330 - Back pressure servo valve; 340 - First back pressure hydraulic control check valve; 350 - Second back pressure hydraulic control check valve; 360 - Back pressure solenoid relief valve; 370 - Back pressure relief valve; 380 - Second pressure sensor. Detailed Implementation

[0018] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0019] In the accompanying drawings, the X-axis represents left and right positions, with the positive direction of the X-axis representing the right side and the negative direction representing the left side; the Z-axis represents up and down positions, with the positive direction of the Z-axis representing the top and the negative direction representing the bottom. It should be noted that the aforementioned representations of the X and Z axes are merely for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the invention.

[0020] It should be noted that the terms "first," "second," etc., used in the specification and claims of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in sequences other than those illustrated or described herein.

[0021] Combination Figure 1As shown, this embodiment of the invention provides an EDT rolling hydraulic system, including a hydraulic cylinder 100. The hydraulic cylinder 100 includes a cylinder body 110, cylinder plugs 120 located within the cylinder body 110, and a cylinder rod 130. The cylinder body 110 includes a first cylinder wall 111 and a second cylinder wall 112 located axially thereon. The cylinder rod 130 slides along the axis of the cylinder body 110 and is slidably engaged with the second cylinder wall 112. At least two cylinder plugs 120 are sleeved on the cylinder rod 130. The cavity between the first cylinder wall 111 and the cylinder plug 120 near the first cylinder wall 111 is a positive pressure cavity, the cavity between the two cylinder plugs 120 is a primary back pressure cavity, and the cavity between the second cylinder wall 112 and the cylinder plug 120 near the second cylinder wall 112 is a secondary back pressure cavity.

[0022] Specifically, based on the orientation of the hydraulic cylinders 100, this embodiment uses a vertically distributed hydraulic cylinder 100 as an example for explanation. In this embodiment, the cylinder rod faces downwards, the top of the cylinder body 110 is the first cylinder wall 111, and the bottom of the cylinder body 110 is the second cylinder wall 112. The cylinder rod 130 slides along the axis of the cylinder body 110 and is in sliding engagement with the second cylinder wall 112. Inside the cylinder body 110, two cylinder plugs 120 can be provided, which are sleeved on the cylinder rod 130, that is, the two cylinder plugs 120 are parallel. In this embodiment, the two cylinder plugs 120 are temporarily named the upper cylinder plug and the lower cylinder plug from top to bottom. The upper cylinder plug is located at the upper end of the cylinder rod 130. The lower cylinder plug is located between the upper cylinder plug and the second cylinder wall 122. The cavity between the first cylinder wall 111 and the upper cylinder plug is a positive pressure cavity, the cavity between the upper cylinder plug and the lower cylinder plug is a primary back pressure cavity, and the cavity between the lower cylinder plug and the second cylinder wall 112 is a secondary back pressure cavity. Figure 1 As shown, Figure 1 In the diagram, P1 represents the positive pressure chamber pressure (cylinder piston chamber pressure), P2 represents the first-stage back pressure chamber pressure (first-stage rod chamber pressure), and P3 represents the second-stage back pressure chamber pressure (second-stage rod chamber pressure). S1 represents the area of ​​the positive pressure chamber, S2 represents the area of ​​the first-stage back pressure chamber (first-stage rod chamber area), and S3 represents the area of ​​the second-stage back pressure chamber (second-stage rod chamber area). The output rolling force F of hydraulic cylinder 100 is calculated as F = P1*S1 - P2*S2 - P3*S3. By increasing the back pressures P2 and P3, the negative rolling force can be increased, thus achieving a small rolling force output while keeping the positive rolling force P1*S1 constant, i.e., EDT rolling condition.

[0023] Therefore, in this embodiment, the cylinder rod 130 slides along the axis of the cylinder body 110 and engages with the second cylinder wall 112, and at least two cylinder plugs 120 are sleeved on the cylinder rod 130. The movement of the cylinder rod 130 is converted into the movement of the two cylinder plugs 120. In the direction of movement of the two cylinder plugs 120, the cavity between the first cylinder wall 111 and the cylinder plug 120 near the first cylinder wall 111 is a positive pressure cavity, and the cavity between the two cylinder plugs 120 is a primary back pressure cavity. The cavity between the second cylinder wall 112 and the cylinder plug 120 near the second cylinder wall 112 is a secondary back pressure cavity. This results in a distribution of positive pressure cavity, primary back pressure cavity, and secondary back pressure cavity inside the cylinder body 110, increasing the working area of ​​the back pressure cavity. This allows the back pressure to be used more effectively to offset part of the rolling force during EDT rolling, thereby achieving a small rolling force output without changing the forward rolling force. This enables precise control of EDT rolling without affecting the control accuracy of conventional cold rolling.

[0024] Optionally, combined Figure 2 As shown, the EDT rolling hydraulic system also includes a positive pressure control link 200. The positive pressure control link 200 includes a positive pressure solenoid directional valve 210, a positive pressure servo valve 220, a first positive pressure hydraulically controlled check valve 230, and a second positive pressure hydraulically controlled check valve 240. One end of the positive pressure solenoid directional valve 210 is connected to the control port X of the first positive pressure hydraulically controlled check valve 230 and the second positive pressure hydraulically controlled check valve 240, respectively. The other two ends of the positive pressure solenoid directional valve 210 are respectively used to connect to the system oil supply P pipe and the system... The system return oil T-pipe is connected. One end of the first positive pressure hydraulic control check valve 230 is connected to port A of the positive pressure servo valve 220, and the other end is connected to the positive pressure chamber. The control oil port Y of the first positive pressure hydraulic control check valve 230 is used to connect to the system drain oil Y-pipe. One end of the second positive pressure hydraulic control check valve 240 is connected to port P of the positive pressure servo valve 220. The control oil port Y of the second positive pressure hydraulic control check valve 240 is used to connect to the system drain oil Y-pipe. The T-port of the positive pressure servo valve 220 is used to connect to the system return oil T-pipe.

[0025] Specifically, the power station supplies hydraulic fluid to the system's P pipe. During normal rolling operation, the positive pressure solenoid directional valve 210 controls the opening of the first positive pressure hydraulic control check valve 230 and the second positive pressure hydraulic control check valve 240. High-pressure hydraulic fluid flows from the system's P pipe through the second positive pressure hydraulic control check valve 240, the positive pressure servo valve 220, and the first positive pressure hydraulic control check valve 230 into the positive pressure chamber, completing the pressing action. When the cylinder lifts, as... Figure 1 As shown, the oil in the positive pressure chamber flows through the first positive pressure hydraulic control check valve 230, the positive pressure servo valve 220 and the positive pressure check valve 290 back to the system return oil Y pipe.

[0026] Thus, by connecting the positive pressure solenoid directional valve 210 to the control ports X of the first positive pressure hydraulic control check valve 230 and the second positive pressure hydraulic control check valve 240 respectively, the positive pressure solenoid directional valve 210 can remotely operate the control ports X of the first positive pressure hydraulic control check valve 230 and the second positive pressure hydraulic control check valve 240 by switching control signals, ensuring timely opening and closing responses of the check valves. The positive pressure servo valve 220, through the connections of its A, P, and T ports, can precisely adjust the flow rate and direction to the positive pressure chamber, allowing it to operate at a lower pressure differential, significantly reducing energy loss and heat generation risk. The first positive pressure hydraulic control check valve 230, based on the output of the positive pressure servo valve 220's A port, unidirectionally guides oil to the positive pressure chamber, effectively preventing oil backflow and maintaining stable pressure. Simultaneously, its control port Y connects to the system's drain Y pipe, ensuring reliable pressure relief of the control oil circuit and preventing malfunctions. The second positive pressure hydraulic control check valve 240 controls the oil flow from the system oil supply P pipe to the positive pressure servo valve 220 in one direction according to the P port input of the positive pressure servo valve 220. Its control oil port Y is also connected to the system drain Y pipe, providing additional one-way protection, thereby enabling precise and reliable control of the positive pressure chamber pressure and improving control efficiency and system stability.

[0027] Optionally, combined Figure 2 As shown, the positive pressure control link 200 also includes a first pressure sensor 250 connected to the cylinder 110. The first pressure sensor 250 is used to detect the pressure of the positive pressure chamber and is communicatively connected to the positive pressure servo valve 220.

[0028] Specifically, the first pressure sensor 250 can be either a piezoresistive pressure sensor or a piezoelectric pressure sensor, which can be bolted to the cylinder body 110. During EDT rolling, the first pressure sensor 250 continuously monitors the pressure changes of the liquid in the positive pressure chamber and converts this pressure data into a recognizable electrical signal, i.e., a positive pressure feedback signal. The positive pressure servo valve 220 can adjust its valve core opening based on the real-time received positive pressure feedback signal, thereby precisely controlling the flow rate of hydraulic oil entering or leaving the positive pressure chamber, achieving closed-loop regulation of the positive pressure chamber pressure.

[0029] Thus, by using the first pressure sensor 250 to detect the pressure of the positive pressure chamber and communicating with the positive pressure servo valve 220, the first pressure sensor 250 can provide real-time feedback on the pressure of the positive pressure chamber, enabling the positive pressure servo valve 220 to adjust the pressure of the positive pressure chamber in a timely manner according to the actual pressure changes. This allows for a more stable maintenance of the preset positive pressure chamber pressure, reducing pressure fluctuations and optimizing the force control effect during the EDT rolling process. Consequently, it improves rolling accuracy and product quality, while also helping to reduce system energy consumption and enhance overall operating efficiency.

[0030] Optionally, combined Figure 2As shown, the positive pressure control link 200 also includes a displacement sensor 260 connected to the cylinder body 110. The displacement sensor 260 is used to detect the movement distance of the cylinder rod 130 and is communicatively connected to the positive pressure servo valve 220.

[0031] Specifically, the displacement sensor 260 can be a magnetostrictive displacement sensor, a drawstring displacement sensor, or other displacement sensors, which can be bolted to the cylinder body 110. During the rolling process, the displacement sensor 260 provides real-time feedback on the movement displacement of the cylinder rod 130. The displacement sensor 260 transmits the detected real-time displacement data of the cylinder rod 130 to the positive pressure servo valve 220 to achieve closed-loop control of the hydraulic system.

[0032] Thus, by detecting the movement distance of the cylinder rod 130 through the displacement sensor 260 connected to the cylinder body 110 and communicating with the positive pressure servo valve 220, the displacement sensor 260 can detect the movement distance of the cylinder rod 130 in real time and feed this position information back to the positive pressure servo valve 220. The positive pressure servo valve 220 compares the received actual position data with the preset target position and dynamically adjusts the pressure output to the positive pressure chamber, thereby achieving precise control of the movement of the cylinder rod 130. This improves the control accuracy and response speed of the EDT rolling hydraulic system, enabling the rolling process to execute commands more accurately, thereby improving the quality and production efficiency of the rolled products.

[0033] Optionally, combined Figure 2 As shown, the hydraulic cylinder 100 also includes two proximity switches 270 connected to the cylinder body 110. The two proximity switches 270 are used to provide feedback on the extreme positions of a single cylinder piston 120 and are communicatively connected to the positive pressure servo valve 220.

[0034] Specifically, the proximity switch 270 can be an inductive proximity switch, a capacitive proximity switch, or a photoelectric proximity switch. It is bolted to a specific position on the cylinder body 110. For example, in this embodiment, the hydraulic cylinder 100 is provided with at least two cylinder plugs 120, and the two cylinder plugs 120 move synchronously. The two proximity switches 270 can be configured to detect the upper and lower limit positions of the lower cylinder plug 120. When the lower cylinder plug 120 moves to its preset upper or lower limit position, the two proximity switches 270 are triggered, thereby generating a position signal to accurately identify the limit position of the cylinder plug 120's movement inside the hydraulic cylinder 100. This avoids the two cylinder plugs 120 colliding with the two ends of the hydraulic cylinder 100, that is, ensuring that the two cylinder plugs 120 do not collide with the upper and lower cylinder bottoms of the hydraulic cylinder 100.

[0035] Thus, two proximity switches 270 connected to the cylinder body 110 are used to provide feedback on the extreme positions of a single cylinder piston 120 and are communicatively connected to the positive pressure servo valve 220. When the cylinder piston 120 moves to its extreme position, the proximity switches 270 can immediately send a feedback signal to the positive pressure servo valve 220, enabling the positive pressure servo valve 220 to adjust the operating state of the hydraulic system in a timely manner, such as by decelerating or stopping, thereby effectively preventing overshoot or hard impact of the cylinder piston 120. At the same time, the extreme position feedback of the cylinder piston 120 also helps protect the hydraulic cylinder 100 and its internal components from mechanical shock and excessive wear, thereby extending the service life of the equipment and enhancing the stability and reliability of the entire EDT rolling hydraulic system.

[0036] Optionally, the positive pressure control link 200 also includes a positive pressure solenoid relief valve 280, which is used to connect the positive pressure chamber and the system return oil T-pipe.

[0037] Specifically, the positive pressure solenoid relief valve 280 can adopt a pilot-operated structure, with a small pilot valve controlling the opening of the main valve. The opening pressure of the pilot valve is regulated by electromagnetic force. When the pilot valve opens, the pressure difference across the main valve drives the main valve to open, thereby achieving a large flow rate of relief to provide more stable pressure control and smaller pressure fluctuations.

[0038] Thus, by using the positive pressure solenoid relief valve 280 to connect the positive pressure chamber and the system return oil T-pipe, during the operation of the hydraulic cylinder 100, when the pressure in the positive pressure chamber abnormally increases due to external load changes or control commands, and reaches the set opening pressure of the positive pressure solenoid relief valve 280, the valve will automatically open. This allows some of the hydraulic oil in the positive pressure chamber to be guided to the system return oil T-pipe through the positive pressure solenoid relief valve 280, thereby rapidly reducing the pressure in the positive pressure chamber and preventing the pressure from continuously rising. This effectively avoids equipment damage, control instability, and potential safety hazards caused by excessive pressure in the hydraulic system under high-pressure conditions. Simultaneously, because the positive pressure solenoid relief valve 280 can provide overflow protection by executing whether to unload or maintain overflow pressure based on electrical signals, it improves the safety and reliability of the entire EDT rolling hydraulic system. Furthermore, it eliminates the need for additional complex components or oil pumps, simplifying the system structure and improving control accuracy and response efficiency.

[0039] Optionally, combined Figure 2 As shown, the positive pressure control link 200 also includes a positive pressure check valve 290, which is connected between the positive pressure servo valve 220 and the system return oil T-pipe.

[0040] Specifically, the positive pressure check valve 290 can be a ball check valve, which controls the opening and closing by the displacement of the ball under the action of fluid pressure. When the positive pressure is sufficient to overcome the spring force, the ball is pushed open, allowing the oil to pass through; when the reverse pressure occurs, the ball is pressed against the valve seat, thereby effectively preventing the oil from flowing back.

[0041] Thus, by placing the positive pressure check valve 290 between the positive pressure servo valve 220 and the system return oil T-pipe, it can be ensured that the oil flowing out of the positive pressure servo valve 220 can only enter the system return oil T-pipe in one direction. This effectively prevents the oil from flowing back from the system return oil T-pipe to the positive pressure servo valve 220 or other parts of the positive pressure control link 200, thereby fundamentally eliminating the backflow phenomenon that may occur during the return oil process. This avoids the system pressure fluctuation and instability problems caused by this, enabling the EDT rolling hydraulic system of this application to maintain more stable pressure control during operation, improving the system's response accuracy and overall operational reliability.

[0042] Optionally, combined Figure 3 As shown, the EDT rolling hydraulic system also includes a back pressure control link 300, which includes a three-way proportional pressure reducing valve 310. One end of the three-way proportional pressure reducing valve 310 is connected to the first-stage back pressure chamber and the second-stage back pressure chamber, respectively. The other three ports of the three-way proportional pressure reducing valve 310 are connected to the system oil supply P pipe, the system oil return T pipe and the system oil drain Y pipe, respectively. Alternatively, the back pressure control link 300 includes a back pressure solenoid directional valve 320, a back pressure servo valve 330, a first back pressure hydraulic check valve 340, and a second back pressure hydraulic check valve 350. One end of the back pressure solenoid directional valve 320 is connected to the control port X of the first back pressure hydraulic check valve 340 and the second back pressure hydraulic check valve 350, respectively, and the other two ends are connected to the system oil supply pipe P and the system oil return pipe T, respectively. One end of the first back pressure hydraulic check valve 340 is connected to the back pressure... The A port of the servo valve 330 is connected, and the other end is connected to the first-stage back pressure chamber and the second-stage back pressure chamber respectively. The Y port of the back pressure hydraulic check valve is connected to the system drain Y pipe. One end of the second back pressure hydraulic control check valve 350 is connected to the P port of the back pressure servo valve 330, and the other end is connected to the system supply P pipe. The Y port of the second back pressure hydraulic control check valve 350 is connected to the system drain Y pipe. The T port of the back pressure servo valve 330 is connected to the system return T pipe through the back pressure return oil check valve.

[0043] Specifically, the back pressure control link 300 in this embodiment includes two implementation methods.

[0044] In the first implementation, the back pressure control link 300 includes a three-way proportional pressure reducing valve 310.

[0045] When the outlet pressure exceeds the set value, the three-way proportional pressure reducing valve 310 can discharge excess oil back to the oil tank. In this embodiment, one end is connected to the primary back pressure chamber and the secondary back pressure chamber respectively, for directly controlling the pressure of these two chambers. Its other three ports are connected to the system oil supply pipe P, the system oil return pipe T, and the system oil drain pipe Y respectively, ensuring the supply, return, and pressure relief of oil. For example, the valve can be a direct-acting proportional pressure reducing valve, which directly drives the valve core through a proportional electromagnet to achieve precise pressure control; or it can be a pilot-operated proportional pressure reducing valve, which controls the action of the main valve core through a pilot stage to handle larger flow rates and pressures.

[0046] In the second implementation, the back pressure control link 300 includes a back pressure solenoid directional valve 320, a back pressure servo valve 330, a first back pressure hydraulic check valve 340, a second back pressure hydraulic check valve 350, and a back pressure solenoid relief valve 360. One end of the back pressure solenoid directional valve 320 is connected to the control port X of the first back pressure hydraulic check valve 340 and the second back pressure hydraulic check valve 350, respectively, to control the opening or closing of these two hydraulic check valves. The other two ends of the back pressure solenoid directional valve 320 are connected to the system oil supply pipe P and the system oil return pipe T, respectively, thereby realizing the switching of the oil supply or discharge path of the back pressure chamber. For example, this valve can be a two-position three-way solenoid directional valve for switching between oil supply and return; or it can be a two-position four-way solenoid directional valve to provide more flexible oil circuit control options. The A port of the back pressure servo valve 330 is connected to one end of the first back pressure hydraulically controlled check valve 340, and the P port of the back pressure servo valve 330 is connected to one end of the second back pressure hydraulically controlled check valve 350. The T port of the back pressure servo valve 330 is connected to the system return oil T pipe through the back pressure return oil check valve. The back pressure servo valve 330 achieves rapid and accurate regulation of the back pressure chamber pressure by precisely controlling the flow rate of oil entering or leaving the back pressure chamber. For example, this servo valve can be a nozzle-flapper type servo valve, controlling the flow rate by changing the relative position of the nozzle and the flap. The first back pressure hydraulically controlled check valve 340 and the second back pressure hydraulically controlled check valve 350 are hydraulically controlled check valves. Their characteristic is that, in addition to having the one-way conduction function of a normal check valve, they can also be reversed by controlling the oil pressure signal. One end of the first back-pressure hydraulically controlled check valve 340 is connected to port A of the back-pressure servo valve 330, and the other end is connected to both the primary and secondary back-pressure chambers. Its Y port is connected to the system drain Y pipe. One end of the second back-pressure hydraulically controlled check valve 350 is connected to port P of the back-pressure servo valve 330, and the other end is connected to the system supply P pipe. Its Y port is connected to the system drain Y pipe. The two hydraulically controlled check valves work together to ensure unidirectional flow of oil in the back-pressure chambers, and can achieve reverse pressure relief or oil supply when needed by controlling the signal at port X, thereby improving the stability and safety of the system. For example, the hydraulically controlled check valve can be a cone valve structure, achieving sealing and unidirectional flow through the cooperation of the cone valve and the valve seat.

[0047] Thus, whether using integrated control with a three-way proportional pressure reducing valve 310 or fine control with a combination of servo valves 330, the back pressure control link 300 in this embodiment can provide more effective and precise back pressure adjustment capabilities. This allows for significant optimization of rolling force and improved control accuracy and stability of EDT rolling, even with a limited working area of ​​the back pressure chamber of the hydraulic cylinder 100.

[0048] Optionally, when the back pressure control link 300 includes a three-way proportional pressure reducing valve 310, the back pressure control link 300 also includes a back pressure relief valve 370, one end of which is connected to the primary back pressure chamber and the secondary back pressure chamber respectively, and the other end is connected to the system return oil T-pipe. Alternatively, when the back pressure control link 300 includes a back pressure solenoid directional valve 320, the back pressure control link 300 also includes a back pressure solenoid relief valve 360, one end of which is connected to the primary back pressure chamber and the secondary back pressure chamber respectively, and the other end is connected to the system return oil T-pipe.

[0049] Specifically, when the back pressure control link 300 includes a three-way proportional pressure reducing valve 310, the back pressure control link 300 also includes a back pressure relief valve 370. When the hydraulic system pressure reaches a preset value, the back pressure relief valve 370 automatically opens to drain excess hydraulic oil back to the oil tank or return oil link, thereby maintaining stable system pressure and preventing overload. One end of the back pressure relief valve 370 is connected to both the primary and secondary back pressure chambers, and the other end is connected to the system return oil T-pipe, effectively controlling the pressure within the back pressure chambers.

[0050] When the back pressure control link 300 includes a back pressure solenoid directional valve 320, the back pressure control link 300 also includes a back pressure solenoid relief valve 360. The back pressure solenoid relief valve 360 ​​can control whether the oil link is unloaded (i.e., whether the hydraulic control system is unloaded) by switching the electromagnet on and off. In this embodiment, one end of the back pressure solenoid relief valve 360 ​​is connected to the primary back pressure chamber and the secondary back pressure chamber respectively, and the other end is connected to the system return oil T-pipe, providing a controllable pressure relief path for the back pressure chamber.

[0051] Thus, when the back pressure control link 300 uses a three-way proportional pressure reducing valve 310 for back pressure control, one end of the back pressure relief valve 370 is connected to the primary back pressure chamber and the secondary back pressure chamber respectively, and the other end is connected to the system return oil T pipe. The back pressure relief valve 370 can monitor the pressure of the primary back pressure chamber and the secondary back pressure chamber in real time. Once the pressure in the chamber exceeds the preset safety threshold due to changes in rolling force or transient response of the system, the back pressure relief valve 370 will automatically open to discharge excess hydraulic oil into the system return oil T pipe in time, thereby rapidly reducing the pressure in the chamber, preventing overpressure from damaging system components, and effectively suppressing pressure fluctuations. When the back pressure control link 300 uses the back pressure solenoid directional valve 320 for back pressure control, one end of the back pressure solenoid relief valve 360 ​​is connected to the primary back pressure chamber and the secondary back pressure chamber respectively, and the other end is connected to the system return oil T pipe. The back pressure solenoid relief valve 360 ​​can unload or maintain the overflow pressure according to the actual working conditions or control commands. This can not only effectively cope with the rapid pressure changes that may occur during the rolling process and avoid overpressure, but also ensure system safety.

[0052] Optionally, the back pressure control link 300 further includes a second pressure sensor 380, which is used to detect the pressure of the primary back pressure chamber and the secondary back pressure chamber. When the back pressure control link 300 includes a three-way proportional pressure reducing valve 310, the second pressure sensor 380 is communicatively connected to the three-way proportional pressure reducing valve 310. Alternatively, when the back pressure control link 300 includes a back pressure servo valve 330, the second pressure sensor 380 is communicatively connected to the back pressure servo valve 330.

[0053] Specifically, the second pressure sensor 380 and the first pressure sensor 250 can use the exact same sensor. During assembly, the second pressure sensor 380 is connected to the back pressure control link 300 to detect the pressure in the primary and secondary back pressure chambers, in conjunction with the preceding text and appendix. Figure 1 When the back pressure control link 300 includes a three-way proportional pressure reducing valve 310, the second pressure sensor 380 is communicatively connected to the three-way proportional pressure reducing valve 310. The detection end of the second pressure sensor 380 is connected after port A of the three-way proportional pressure reducing valve 310 to detect the pressure of the primary back pressure chamber and the secondary back pressure chamber. Alternatively, in conjunction with the foregoing and appendix... Figure 2 When the back pressure control link 300 includes the back pressure solenoid directional valve 320, the second pressure sensor 380 is communicatively connected to the back pressure servo valve 330. The detection end of the second pressure sensor 380 is connected after the first back pressure hydraulic check valve 340. The pressure after the valve is measured to be the pressure of the first-stage back pressure chamber and the second-stage back pressure chamber.

[0054] Thus, the second pressure sensor 380 is used to detect the pressure in the primary and secondary back pressure chambers and is communicatively connected to the back pressure servo valve 330 or the three-way proportional pressure reducing valve 310. The second pressure sensor 380 can detect the actual pressure in the primary and secondary back pressure chambers in real time and accurately, and promptly feed these pressure signals back to the back pressure servo valve 330 or the three-way proportional pressure reducing valve 310. The back pressure servo valve 330 or the three-way proportional pressure reducing valve 310 compares the received actual pressure value with the preset target pressure value and dynamically adjusts its opening based on this difference, thereby controlling the flow and pressure of hydraulic oil entering or exiting the back pressure chamber. This allows the EDT rolling hydraulic system to quickly respond to pressure fluctuations caused by load changes during rolling, continuously maintaining the back pressure chamber pressure within the set range, and significantly improving the control accuracy and stability of the rolling force.

[0055] Based on the above embodiments, when the back pressure control link 300 includes a three-way proportional pressure reducing valve 310 (similar in principle to when the back pressure control link 300 includes a back pressure solenoid directional valve 320), the control process of the EDT rolling hydraulic system in this embodiment can be as follows: During normal rolling operation, the positive pressure solenoid directional valve 210 controls the opening of the first positive pressure hydraulic control check valve 230 and the second positive pressure hydraulic control check valve 240. High-pressure oil flows from the system P pipe through the second positive pressure hydraulic control check valve 240, the positive pressure servo valve 220, and the first positive pressure hydraulic control check valve 230 into the positive pressure chamber. Simultaneously, the positive pressure servo valve 220 and the displacement sensor 260 perform closed-loop position control. The oil in the back pressure chamber flows back to the return oil T-pipe through the three-way proportional pressure reducing valve 310, completing the pressing action. At this time, the three-way proportional pressure reducing valve 310 only provides a small back pressure to the cylinder rod chamber, so that the positive pressure chamber can achieve a large rolling force output. When the cylinder is lifted, the high-pressure oil in the system P-pipe flows through the three-way proportional pressure reducing valve 310 into the two back pressure chambers of the cylinder body 110. At the same time, the oil in the positive pressure chamber flows back to the system return oil T-pipe through the first positive pressure hydraulic control check valve 230, the positive pressure servo valve 220, and the positive pressure check valve 290. Among them, the positive pressure solenoid relief valve 280 is used for overflow protection when the pressure in the AGC cylinder body 110 is too high.

[0056] When in EDT rolling condition, the second pressure sensor 380 detects the pressure of the two back pressure chambers and performs closed-loop pressure control with the three-way proportional pressure reducing valve 310 to ensure that a large back pressure is provided to the two back pressure chambers.

[0057] The first pressure sensor 250 detects the pressure in the positive pressure chamber and performs closed-loop pressure control with the positive pressure servo valve 220 to provide the positive force for rolling. Since P in the calculation of the negative force (F=P*S) is the large back pressure provided by the three-way proportional pressure reducing valve 2, and since the two back pressure chambers provided by this invention increase the working area S of the back pressure chamber in the formula, the negative force is also greatly increased, thus enabling the EDT rolling condition with a very small output rolling force to be achieved.

[0058] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. An EDT rolling hydraulic system, characterized in that, The system includes a hydraulic cylinder (100), which includes a cylinder body (110), cylinder plugs (120) located within the cylinder body (110), and cylinder rods (130). The cylinder body (110) includes a first cylinder wall (111) and a second cylinder wall (112) located in its axial direction. The cylinder rod (130) slides along the axis of the cylinder body (110) and is in slidable engagement with the second cylinder wall (112). At least two cylinder plugs (120) are sleeved on the cylinder rod (130). The cavity between the first cylinder wall (111) and the cylinder plug (120) near the first cylinder wall (111) is a positive pressure cavity, the cavity between the two cylinder plugs (120) is a primary back pressure cavity, and the cavity between the second cylinder wall (112) and the cylinder plug (120) near the second cylinder wall (112) is a secondary back pressure cavity. It also includes a back pressure control link (300), which includes a three-way proportional pressure reducing valve (310). One end of the three-way proportional pressure reducing valve is connected to the first-stage back pressure chamber and the second-stage back pressure chamber, respectively. The other three ports of the three-way proportional pressure reducing valve are connected to the system oil supply P pipe, the system oil return T pipe and the system oil drain Y pipe, respectively. Alternatively, the back pressure control link (300) includes a back pressure solenoid directional valve (320), a back pressure servo valve (330), a first back pressure hydraulic control check valve (340), and a second back pressure hydraulic control check valve (350). One end of the back pressure solenoid directional valve (320) is connected to the control port X of the first back pressure hydraulic control check valve (340) and the second back pressure hydraulic control check valve (350), respectively, and the other two ends are connected to the system oil supply pipe P and the system oil return pipe T, respectively. One end of the first back pressure hydraulic control check valve (340) is connected to the back pressure... The A port of the servo valve (330) is connected, and the other end is connected to the first-stage back pressure chamber and the second-stage back pressure chamber respectively. The Y port of the first back pressure hydraulic control check valve (340) is connected to the system drain Y pipe. One end of the second back pressure hydraulic control check valve (350) is connected to the P port of the back pressure servo valve (330), and the other end is connected to the system supply P pipe. The Y port of the second back pressure hydraulic control check valve (350) is connected to the system drain Y pipe. The T port of the back pressure servo valve (330) is connected to the system return T pipe through the back pressure return oil check valve.

2. The EDT rolling hydraulic system according to claim 1, characterized in that, It also includes a positive pressure control link (200), which includes a positive pressure solenoid directional valve (210), a positive pressure servo valve (220), a first positive pressure hydraulic check valve (230), and a second positive pressure hydraulic check valve (240). One end of the positive pressure solenoid directional valve (210) is connected to the control port X of the first positive pressure hydraulic check valve (230) and the second positive pressure hydraulic check valve (240), respectively. The other two ends of the positive pressure solenoid directional valve (210) are respectively used to connect to the system oil supply pipe P and the system oil return pipe T. One end of the first positive pressure hydraulic control check valve (230) is connected to port A of the positive pressure servo valve (220), and the other end is connected to the positive pressure chamber. The control port Y of the first positive pressure hydraulic control check valve (230) is used to connect to the system drain Y pipe. One end of the second positive pressure hydraulic control check valve (240) is connected to port P of the positive pressure servo valve (220). The control port Y of the second positive pressure hydraulic control check valve (240) is used to connect to the system drain Y pipe. The T port of the positive pressure servo valve (220) is used to connect to the system return T pipe.

3. The EDT rolling hydraulic system according to claim 2, characterized in that, The positive pressure control link (200) also includes a first pressure sensor (250) connected to the cylinder (110), the first pressure sensor (250) being used to detect the pressure of the positive pressure chamber and communicating with the positive pressure servo valve (220).

4. The EDT rolling hydraulic system according to claim 2, characterized in that, The positive pressure control link (200) also includes a displacement sensor (260) connected to the cylinder (110), the displacement sensor (260) is used to detect the movement distance of the cylinder rod (130) and is communicatively connected to the positive pressure servo valve (220).

5. The EDT rolling hydraulic system according to claim 4, characterized in that, The hydraulic cylinder (100) also includes two proximity switches (270) connected to the cylinder body (110). The two proximity switches (270) are used to provide feedback on the extreme positions of a single cylinder piston (120) and are communicatively connected to the positive pressure servo valve (220).

6. The EDT rolling hydraulic system according to claim 2, characterized in that, The positive pressure control link (200) also includes a positive pressure solenoid relief valve (280), which is used to connect the positive pressure chamber and the system return oil T-pipe.

7. The EDT rolling hydraulic system according to claim 2, characterized in that, The positive pressure control link (200) also includes a positive pressure check valve (290), which is connected between the positive pressure servo valve (220) and the system return oil T-pipe.

8. The EDT rolling hydraulic system according to claim 1, characterized in that, When the back pressure control link (300) includes a three-way proportional pressure reducing valve (310), the back pressure control link (300) also includes a back pressure relief valve (370), one end of which is connected to the first-stage back pressure chamber and the second-stage back pressure chamber respectively, and the other end is connected to the system return oil T-pipe. Alternatively, when the back pressure control link (300) includes a back pressure solenoid directional valve (320), the back pressure control link (300) also includes a back pressure solenoid relief valve (360), one end of which is connected to the first-stage back pressure chamber and the second-stage back pressure chamber respectively, and the other end is connected to the system return oil T-pipe.

9. The EDT rolling hydraulic system according to claim 1, characterized in that, The back pressure control link (300) further includes a second pressure sensor (380), which is used to detect the pressure of the first-stage back pressure chamber and the second-stage back pressure chamber. When the back pressure control link (300) includes a three-way proportional pressure reducing valve (310), the second pressure sensor (380) is communicatively connected to the three-way proportional pressure reducing valve (310). Alternatively, when the back pressure control link (300) includes the back pressure servo valve (330), the second pressure sensor (380) is communicatively connected to the back pressure servo valve (330).

Images