A hydraulic system for a sagger hydraulic device

Abstract

This invention discloses a hydraulic system for a sagger hydraulic device, comprising a demolding cylinder, a first valve group, and a second valve group. The first valve group includes a first cartridge valve and a third cartridge valve, while the second valve group includes a second cartridge valve, a suction cartridge valve, and a fourth cartridge valve. The suction port of the suction cartridge valve is connected to an oil tank, and the main suction port of the suction cartridge valve is connected to the piston rod chamber. The suction port and the main suction port are interconnected. The first cartridge valve supplies oil to the piston chamber, thereby driving the piston rod in the demolding cylinder to move downwards. The second cartridge valve supplies oil to the piston rod chamber, causing the piston rod in the demolding cylinder to move upwards. Using this invention, negative pressure in the demolding cylinder can be avoided when pressing the side of the sagger, and the piston movement speed of the demolding cylinder can be made consistent with that of the ejection cylinder, ensuring the pressing effect and saving energy.

Description

Technical Field

[0001] This invention relates to the field of hydraulic system technology, and more particularly to a hydraulic system for a sagger hydraulic device. Background Technology

[0002] A sagger is a container used for storing or transporting specific items, and saggers can be manufactured using hydraulic equipment. A sagger generally consists of a bottom and four sides. Existing hydraulic equipment for saggers typically includes a frame, a main hydraulic cylinder, an ejector cylinder, a demolding cylinder, a floating frame, and a mold. The main hydraulic cylinder is located above the ejector cylinder. When pressing the sagger, the bottom is pressed down by the main hydraulic cylinder, while the sides are pressed up by the ejector cylinder. Pressure is applied simultaneously in both directions, but usually the bottom is pressed first. After the bottom is formed, the main hydraulic cylinder maintains pressure while the ejector cylinder continues to apply pressure from bottom to top. However, due to the significant friction between the side powder and the mold cavity, the friction will cause the mold to move upward during the upward pressurization process of the ejector cylinder. Since the mold is connected to the floating frame and the demolding cylinder respectively, the mold will cause the pistons of the floating frame and the demolding cylinder to move upward, which will generate negative pressure in the lower chamber of the demolding cylinder, affecting the subsequent normal operation of the demolding cylinder. Even if oil is injected into the lower chamber of the demolding cylinder to eliminate the negative pressure, the piston's movement speed will be difficult to control due to the increased factors controlling the movement of the piston. Its movement speed is prone to inconsistency with that of the ejector cylinder, which will not only affect the pressing effect, but also generate energy consumption during the oil injection and pressurization process. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a hydraulic system for a sagger hydraulic device that can prevent negative pressure from being generated in the demolding cylinder when pressing the side of the sagger, and can make the piston of the demolding cylinder move at the same speed as the ejection cylinder, thus ensuring the pressing effect and saving energy.

[0004] To solve the above-mentioned technical problems, the present invention provides a hydraulic system for a crucible hydraulic device, including a demolding cylinder, a first valve group connected to the piston chamber of the demolding cylinder, and a second valve group connected to the piston rod chamber of the demolding cylinder. The first valve group includes a first cartridge valve, the first side port of the first cartridge valve is connected to the main oil circuit, the first main oil port of the first cartridge valve is connected to the piston chamber, and the first side port and the first main oil port can communicate with each other.

[0005] The second valve assembly includes a second cartridge valve and a suction cartridge valve. The second side port of the second cartridge valve is connected to the main oil circuit, and the second side port and the second main port are interconnected. The second main port of the second cartridge valve is connected to the piston rod chamber. The suction side port of the suction cartridge valve is connected to the oil tank, and the suction main port of the suction cartridge valve is connected to the piston rod chamber. The suction side port and the suction main port are interconnected.

[0006] As an improvement to the above solution, the hydraulic system for the saucer hydraulic equipment further includes a control valve group, which includes a suction control valve. The suction control valve is connected to the suction cartridge valve. When the suction control valve is energized, the suction cartridge valve opens, and the main suction port is connected to the suction side port.

[0007] As an improvement to the above solution, the suction cartridge valve further includes a first upper control chamber and a first lower control chamber. When the suction control valve is energized, the first upper control chamber is connected to the oil tank, and the first lower control chamber is connected to the control oil circuit.

[0008] As an improvement to the above solution, the control valve group further includes a first control valve, the first cartridge valve having a first control chamber, the first control chamber being connected to the first control valve.

[0009] When the first control valve is de-energized, the first control chamber is connected to the control oil circuit; when the first control valve is energized, the first control chamber is connected to the oil tank, and the first side oil port and the first main oil port are connected.

[0010] As an improvement to the above solution, the control valve group further includes a second control valve, the second cartridge valve having a second control chamber, the second control chamber being connected to the second control valve.

[0011] When the second control valve is de-energized, the second control chamber is connected to the control oil circuit; when the second control valve is energized, the second control chamber is connected to the oil tank, and the second side oil port and the second main oil port are connected.

[0012] As an improvement to the above scheme, the first valve group further includes the third cartridge valve, which can be arranged in parallel with the first cartridge valve. The third cartridge valve includes a third side port and a third main port. The third side port is connected to the oil tank, and the third main port and the first main port are simultaneously connected to the piston chamber.

[0013] As an improvement to the above scheme, the control valve group further includes a third control valve, and the third cartridge valve further includes a second upper control chamber and a second lower control chamber, and the third control valve is connected to the second upper control chamber and the second lower control chamber respectively.

[0014] When the third control valve is energized, the second upper control chamber is connected to the control oil circuit, the second lower control chamber is connected to the oil tank, and the third side oil port is connected to the oil tank.

[0015] When the third control valve is de-energized, the second upper control chamber is connected to the oil tank, the second lower control chamber is connected to the control oil circuit, the third side oil port is connected to the third main oil port, and is connected to the oil tank.

[0016] As an improvement to the above solution, the hydraulic system for the sauté hydraulic equipment further includes a relief valve assembly, which includes a first relief valve connected between the oil tank and the piston rod chamber, and one end of the first relief valve connected to the second main oil port.

[0017] As an improvement to the above solution, the second valve group further includes a fourth cartridge valve, which can be connected in parallel with the second cartridge valve. The fourth cartridge valve includes a fourth side port and a fourth main port. The overflow valve group further includes a second overflow valve, which is located between the fourth side port and the oil tank. The fourth side port is connected to the second overflow valve, and the second overflow valve is connected to the oil tank. The fourth main port and the second main port are simultaneously connected to the piston rod chamber.

[0018] As an improvement to the above solution, the control valve group further includes a fourth control valve, which has a fourth control chamber and is connected to the fourth control valve.

[0019] When the fourth control valve is de-energized, the fourth control chamber is connected to the control oil circuit.

[0020] Implementing this invention has the following beneficial effects:

[0021] The hydraulic system of the present invention for a sautéing hydraulic equipment includes a demolding cylinder, a first valve group, and a second valve group. The first valve group includes a first cartridge valve, and the second valve group includes a second cartridge valve and a suction cartridge valve. The first cartridge valve can supply oil to the piston chamber, thereby driving the piston rod in the demolding cylinder to move downward, while the second cartridge valve can supply oil to the piston rod chamber, causing the piston rod in the demolding cylinder to move upward. When the ejector cylinder moves upward to pressurize the side of the sagger, causing the pistons of the floating frame and the demolding cylinder to move upward, the second cartridge valve is closed and the suction cartridge valve is opened. Because the second cartridge valve is closed, hydraulic oil will not actively enter the piston rod cavity. Instead, the piston rod cavity will be passively sucked from the oil tank through the suction cartridge valve, thereby avoiding negative pressure in the piston rod cavity. Moreover, this passive oil suction will not exert force on the piston rod in the demolding cylinder, so that the piston rod in the demolding cylinder can follow the moving distance of the ejector cylinder, making the moving speed of the floating frame, mold and ejector cylinder equal and preventing misalignment. While ensuring the pressing effect, it also saves energy for the second cartridge valve to actively supply oil. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the hydraulic system of the present invention used in a sagger hydraulic device;

[0023] Figure 2 yes Figure 1 A magnified view of part A in the image;

[0024] Figure 3 yes Figure 1 A magnified view of part B in the image;

[0025] Figure 4 This is a schematic diagram of the system when the piston rod of the demolding cylinder of the present invention moves downward;

[0026] Figure 5 This is a schematic diagram of the system when the piston rod of the demolding cylinder of the present invention is passively sucking in oil. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. It is hereby declared that the directional terms such as up, down, left, right, front, back, inside, and outside used in this text are based solely on the accompanying drawings and are not intended to specifically limit the invention.

[0028] See Figure 1 , Figure 2 and Figure 3This invention discloses a hydraulic system for a hydraulic equipment for a crucible 60, including a demolding cylinder 1, a first valve group 2 connected to the piston chamber 11 of the demolding cylinder 1, and a second valve group 3 connected to the piston rod chamber 12 of the demolding cylinder 1. The demolding cylinder 1 is provided with a piston and a piston rod. The side of the demolding cylinder 1 where the piston is located is the piston chamber 11, and the side where the piston rod is located is the piston rod chamber 12. In this embodiment of the invention, the piston chamber 11 is located at the upper part, and the piston rod chamber 12 is located at the lower part.

[0029] In this embodiment of the invention, the first valve group 2 includes a first cartridge valve 21. The first side port 211 of the first cartridge valve 21 is connected to the main oil passage 10, and the first main port 212 of the first cartridge valve 21 is connected to the piston chamber 11. The first cartridge valve 21 can supply oil from the main oil passage 10 to the piston chamber 11, thereby driving the piston rod of the demolding cylinder 1 to move downward. The second valve group 3 includes a second cartridge valve 31 and an oil suction cartridge valve 32. The second side port 311 of the second cartridge valve 31 is connected to the main oil passage 10, and the second main port 312 of the second cartridge valve 31 is connected to the piston rod chamber 12. The second side port 311 and the second main port 312 can communicate with each other. The second cartridge valve 31 can supply oil from the main oil passage 10 to the piston rod chamber 12, thereby driving the piston rod of the demolding cylinder 1 to move upward. The suction side port 321 of the suction cartridge valve 32 is connected to the oil tank 20, and the main suction port 322 of the suction cartridge valve 32 is connected to the piston rod chamber 12. The suction side port 321 and the main suction port 322 can be connected to each other, and the oil supply pressure of the main oil circuit 10 is P.

[0030] In the hydraulic equipment of the crucible 60, the piston rod is usually connected downward to the floating frame 40, and the floating frame 40 is connected to the mold 50. The powder is located inside the mold 50. After the main oil cylinder 70 completes the pressing and forming of the surface of the crucible 60, the main oil cylinder 70 holds the pressure, while the ejector oil cylinder 80 continues to pressurize from bottom to top. During the pressurization process, the friction between the powder and the mold 50 will drive the piston rod to move upward through the floating frame 40. At this time, the volume of the piston rod cavity 12 increases. If oil is not supplied to the piston cavity 11, a vacuum effect will occur, thereby generating negative pressure. By setting the oil suction cartridge valve 32, during the upward movement of the piston rod, the piston rod cavity 12 draws oil from the oil tank 20 through the oil suction cartridge valve 32. Unlike the second cartridge valve 31, which supplies oil to the piston rod cavity 12 from the main oil circuit 10, this oil suction is passive. The oil intake does not exert force on the piston rod, thus not driving it upward. This ensures that the piston rod moves entirely according to the moving distance of the ejector cylinder 80. The moving speed of the ejector cylinder 80, the floating frame 40, and the mold 50 is equal, preventing misalignment and ensuring the pressing effect. Furthermore, there is no need to actively supply oil to the second cartridge valve 31, saving energy.

[0031] Therefore, the beneficial effects of the embodiments of the present invention are as follows:

[0032] The hydraulic system of the hydraulic equipment for the crucible 60 in this embodiment of the invention includes a demolding cylinder 1, a first valve group 2, and a second valve group 3. The first valve group 2 includes a first cartridge valve 21, and the second valve group 3 includes a second cartridge valve 31 and an oil suction cartridge valve 32. The first cartridge valve 21 can supply oil to the piston chamber 11, thereby driving the piston rod in the demolding cylinder 1 to move downward, while the second cartridge valve 31 can supply oil to the piston rod chamber 12, causing the piston rod in the demolding cylinder 1 to move upward. When the ejector cylinder 80 moves upward and pressurizes the side of the sagger 60, causing the piston of the floating frame 40 and the demolding cylinder 1 to move upward, the second cartridge valve 31 is closed and the suction cartridge valve 32 is opened. Since the second cartridge valve 31 is closed, hydraulic oil will not actively enter the piston rod chamber 12. Instead, the piston rod chamber 12 will be passively sucked from the oil tank 20 through the suction cartridge valve 32, thereby avoiding negative pressure in the piston rod chamber 12. Moreover, this passive oil suction will not exert force on the piston rod in the demolding cylinder 1, so that the piston rod in the demolding cylinder 1 can follow the moving distance of the ejector cylinder 80, making the speed of the floating frame 40, the mold 50 and the ejector cylinder 80 equal and preventing misalignment. While ensuring the pressing effect, it also saves energy for the second cartridge valve 31 to actively supply oil.

[0033] Specifically, the hydraulic system for the hydraulic equipment of the crucible 60 further includes a control valve assembly 4 for controlling the opening and closing of the first valve assembly 2 and the second valve assembly 3. The control valve assembly 4 includes a suction control valve 41, which is connected to the suction cartridge valve 32. The suction control valve 41 controls the opening and closing of the suction cartridge valve 32. When the suction control valve 41 is energized, the suction cartridge valve 32 opens, and the main suction port 322 connects to the suction side port 321. At this time, the piston rod chamber 12 can draw oil from the oil tank 20 through the suction cartridge valve 32. The suction cartridge valve 32 includes a first upper control chamber 323 and a first lower control chamber 324. When the suction control valve 41 is energized, the first upper control chamber 323 is connected to the oil tank 20, and the valve core of the suction cartridge valve 32 moves upward, allowing the control oil in the first upper control chamber 323 to return to the oil tank 20. The first lower control chamber 324 is connected to the control oil circuit 30, which supplies oil to the first lower control chamber 324, causing the valve core of the suction cartridge valve 32 to move upward, thereby opening the suction control valve 41. The oil supply pressure of the control oil circuit 30 is Px.

[0034] The control valve assembly 4 further includes a first control valve 42 for controlling the first cartridge valve 21. The first cartridge valve 21 has a first control chamber 213, which is connected to the first control valve 42. When the first control valve 42 is de-energized, the first control chamber 213 is connected to the control oil circuit 30. At this time, the pressure of the valve core of the first cartridge valve 21 by the first control chamber 213 is relatively large, and the first cartridge valve 21 is in a closed state. When the first control valve 42 is energized, the first control chamber 213 is connected to the oil tank 20, the pressure of the first control chamber 213 decreases, and the first cartridge valve 21 opens under the force of the first main oil port 212. The first side oil port 211 is connected to the first main oil port 212.

[0035] The control valve assembly 4 further includes a second control valve 43 for controlling the second cartridge valve 31. The second cartridge valve 31 has a second control chamber 313, which is connected to the second control valve 43. When the second control valve 43 is de-energized, the second control chamber 313 is connected to the control oil circuit 30. At this time, the pressure of the valve core of the second cartridge valve 31 by the second control chamber 313 is relatively large, and the second cartridge valve 31 is in a closed state. When the second control valve 43 is energized, the second control chamber 313 is connected to the oil tank 20, the pressure of the second control chamber 313 decreases, and the second cartridge valve 31 opens under the oil pressure of the second main oil port 312. The second side oil port 311 and the second main oil port 312 are connected. In this embodiment of the invention, the first side oil port 211 and the second side oil port 311 are interconnected and jointly connected to the main oil circuit 10.

[0036] In order to distinguish between active oil supply and passive oil discharge, the first valve group 2 also includes the third cartridge valve 22. The third cartridge valve 22 can be arranged in parallel with the first cartridge valve 21. The third cartridge valve 22 includes a third side port 221 and a third main port 222. The third side port 221 is connected to the oil tank 20. The third main port 222 and the first main port 212 are connected to the piston chamber 11. When the second cartridge valve 31 actively supplies oil to the piston rod chamber 12 to make the piston rod rise, the hydraulic oil in the piston chamber 11 can be passively discharged to the oil tank 20 through the third cartridge valve 22.

[0037] To control the third cartridge valve 22, the control valve assembly 4 further includes a third control valve 44. The third cartridge valve 22 also includes a second upper control chamber 223 and a second lower control chamber 224. The third control valve 44 is connected to the second upper control chamber 223 and the second lower control chamber 224 respectively. When the third control valve 44 is de-energized, the second upper control chamber 223 is connected to the oil tank 20, and the second lower control chamber 224 is connected to the control oil circuit 30. At this time, the pressure in the second lower control chamber 224 is greater than that in the second upper control chamber 223, and the valve core of the third cartridge valve 22 rises, thereby opening the third cartridge valve 22. The third side oil port 221 is connected to the third main oil port 222, and the third side oil port 221 is connected to the oil tank 20, enabling passive oil discharge. When the third control valve 44 is energized, the second upper control chamber 223 is connected to the control oil circuit 30, and the second lower control chamber 224 is connected to the oil tank 20. At this time, the pressure of the second lower control chamber 224 is less than the pressure of the second upper control chamber 223, and the valve core of the third cartridge valve 22 descends or remains in the lower part, thereby closing the third cartridge valve 22.

[0038] It should be noted that the control oil circuit 30 simultaneously controls the first control chamber 213 and the second lower control chamber 224. When the third control valve 44 is de-energized, the third cartridge valve 22 opens, while the first control valve 42 is de-energized and the first cartridge valve 21 is closed. This prevents the oil pressure of the main oil circuit 10 from being transmitted to the piston chamber 11 through the first cartridge valve 21, facilitating passive oil discharge from the piston chamber 11 via the third cartridge valve 22. Similarly, when the first control valve 42 is energized, the first cartridge valve 21 opens to actively supply oil to the piston chamber 11, and the third control valve 44 is energized, the third cartridge valve 22 closes, preventing the hydraulic oil in the first cartridge valve 21 from flowing back into the oil tank 20 through the third cartridge valve 22.

[0039] When the piston rod chamber 12 is passively sucked in oil, and the third control valve 44 is de-energized, the third cartridge valve 22 opens, and the oil discharged from the piston chamber 11 enters the oil tank 20 through the third cartridge valve 22, thereby realizing the passive oil discharge from the piston chamber 11.

[0040] The hydraulic system for the hydraulic equipment used in the crucible 60 also includes a relief valve assembly 5. The relief valve assembly 5 includes a first relief valve 51 and a second relief valve 52. The first relief valve 51 is connected between the oil tank 20 and the piston rod chamber 12, with one end connected to the second main oil port 312. The second relief valve 52 is located between the fourth side oil port 331 and the oil tank 20, with one end connected to the fourth side oil port 331. The first relief valve 51 prevents excessive pressure in the piston rod chamber 12, and the second relief valve 52 creates back pressure on the piston rod chamber 12, preventing the demolding cylinder from losing weight and falling.

[0041] The second valve assembly 3 further includes a fourth cartridge valve 33, which can be connected in parallel with the second cartridge valve 31. The fourth cartridge valve 33 includes a fourth side port 331 and a fourth main port 332. The second relief valve 52 is located between the fourth side port 331 and the oil tank 20. The fourth side port 331 is connected to the second relief valve 52, and the second relief valve 52 is connected to the oil tank 20. Therefore, the fourth side port 331 is connected to the oil tank 20 through the second relief valve 52. The fourth main port 332 and the second main port 312 are simultaneously connected to the piston rod chamber 12. When the first cartridge valve 21 actively supplies oil to the piston chamber 11 to move the piston rod downward, the hydraulic oil in the piston rod chamber 12 can be passively discharged into the oil tank 20 through the fourth cartridge valve 33 and the second relief valve 52.

[0042] To control the fourth cartridge valve 33, the control valve assembly 4 further includes a fourth control valve 45. The fourth cartridge valve 33 has a fourth control chamber 333, which is connected to the fourth control valve 45. When the fourth control valve 45 is energized, the fourth control chamber 333 is connected to the oil tank 20, and the pressure in the fourth control chamber 333 is relatively low. When the piston rod chamber 12 is passively discharged, the hydraulic oil passively discharged from the piston rod chamber 12 can push the valve core of the fourth cartridge valve 33, causing the fourth cartridge valve 33 to open. The fourth side port 331 and the fourth main port 332 are connected, thereby facilitating the passive discharge of oil from the piston rod chamber 12.

[0043] When using, see Figure 4 When the first control valve 42 is energized, the first cartridge valve 21 opens to actively supply oil to the piston chamber 11, and the hydraulic oil in the piston rod chamber 12 is passively discharged. Under the action of oil pressure, the fourth cartridge valve 33 opens to passively discharge oil from the piston rod chamber 12, and the piston rod can move downward. At this time, the second control valve 43 is de-energized and the third control valve 44 is energized, and both the second cartridge valve 31 and the third cartridge valve 22 are closed.

[0044] During the upward pressurization and movement of the ejector cylinder 80, see... Figure 5 The second control valve 43 and the third control valve 44 are de-energized, the second cartridge valve closes to avoid affecting the passive oil intake of the piston rod chamber, and the third cartridge valve opens to allow the hydraulic oil in the piston chamber 11 to be passively discharged from the third cartridge valve 22. During the upward movement of the piston rod, the first control valve 42 and the fourth control valve 45 are de-energized, the first cartridge valve 21 closes to stop supplying oil to the piston chamber 11, and the fourth cartridge valve 33 closes. Meanwhile, the oil intake control valve 41 is energized, the oil intake cartridge valve 32 opens, and the piston rod chamber 12 can passively draw oil from the oil tank 20 through the oil intake cartridge valve 32.

[0045] The above are preferred embodiments of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A hydraulic system for a sagger hydraulic device, characterized in that, It includes a demolding cylinder, a first valve group connected to the piston chamber of the demolding cylinder, and a second valve group connected to the piston rod chamber of the demolding cylinder. The first valve group includes a first cartridge valve, the first side port of the first cartridge valve is connected to the main oil circuit, the first main oil port of the first cartridge valve is connected to the piston chamber, and the first side port and the first main oil port can communicate with each other. The second valve assembly includes a second cartridge valve and a suction cartridge valve. The second side port of the second cartridge valve is connected to the main oil circuit, and the second main oil port of the second cartridge valve is connected to the piston rod chamber. The second side port and the second main oil port can communicate with each other. The suction side port of the suction cartridge valve is connected to the oil tank, and the suction main oil port of the suction cartridge valve is connected to the piston rod chamber. The suction side port and the suction main oil port can communicate with each other. The hydraulic system for the sagger hydraulic equipment also includes a control valve group, which includes a suction control valve. The suction control valve is connected to the suction cartridge valve. When the suction control valve is energized, the suction cartridge valve opens, and the main suction port is connected to the suction side port. The oil suction cartridge valve further includes a first upper control chamber and a first lower control chamber. When the oil suction control valve is energized, the first upper control chamber is connected to the oil tank, and the first lower control chamber is connected to the control oil circuit. The first valve group further includes a third cartridge valve, which can be connected in parallel with the first cartridge valve. The third cartridge valve includes a third side port and a third main port. The third side port is connected to the oil tank, and the third main port and the first main port are simultaneously connected to the piston chamber. The control valve assembly further includes a third control valve, and the third cartridge valve further includes a second upper control chamber and a second lower control chamber. The third control valve is connected to the second upper control chamber and the second lower control chamber respectively. When the third control valve is energized, the second upper control chamber is connected to the control oil circuit, the second lower control chamber is connected to the oil tank, and the third side oil port is connected to the oil tank; When the third control valve is de-energized, the second upper control chamber is connected to the oil tank, the second lower control chamber is connected to the control oil circuit, the third side oil port is connected to the third main oil port, and is connected to the oil tank; The hydraulic system for the sauté hydraulic equipment further includes a relief valve assembly, which includes a first relief valve connected between the oil tank and the piston rod chamber, with one end of the first relief valve connected to the second main oil port.

2. The hydraulic system for a sagger hydraulic device according to claim 1, characterized in that, The control valve assembly further includes a first control valve, the first cartridge valve having a first control chamber, the first control chamber being connected to the first control valve; When the first control valve is de-energized, the first control chamber is connected to the control oil circuit; when the first control valve is energized, the first control chamber is connected to the oil tank, and the first side oil port and the first main oil port are connected.

3. The hydraulic system for a sagger hydraulic device according to claim 1, characterized in that, The control valve assembly further includes a second control valve, the second cartridge valve having a second control chamber, the second control chamber being connected to the second control valve; When the second control valve is de-energized, the second control chamber is connected to the control oil circuit; when the second control valve is energized, the second control chamber is connected to the oil tank, and the second side oil port and the second main oil port are connected.

4. The hydraulic system for a sagger hydraulic device according to claim 1, characterized in that, The second valve assembly further includes a fourth cartridge valve, which can be connected in parallel with the second cartridge valve. The fourth cartridge valve includes a fourth side port and a fourth main port. The overflow valve assembly further includes a second overflow valve, which is located between the fourth side port and the oil tank. The fourth side port is connected to the second overflow valve, and the second overflow valve is connected to the oil tank. The fourth main port and the second main port are simultaneously connected to the piston rod chamber.

5. The hydraulic system for a sagger hydraulic device according to claim 4, characterized in that, The control valve assembly further includes a fourth control valve, the fourth cartridge valve having a fourth control chamber, the fourth control chamber being connected to the fourth control valve; When the fourth control valve is de-energized, the fourth control chamber is connected to the control oil circuit.

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