Hydraulic control system of oil cylinder and hydraulic control system of hot handling material loading machine

Abstract

The utility model discloses a kind of oil cylinder hydraulic control system and heat treatment loading and unloading machine hydraulic control system, belong to hydraulic control technical field, wherein oil cylinder hydraulic control system includes oil cylinder uplink on-off valve group, oil cylinder pressure-keeping on-off valve group and oil cylinder downlink control valve group;Oil cylinder downlink control valve group includes two-way plug-in proportional valve with pilot valve.Heat treatment loading and unloading machine hydraulic control system includes oil cylinder and above-mentioned oil cylinder hydraulic control system, and the stem cavity of oil cylinder is communicated with oil tank.Two-way plug-in proportional valve, the opening of valve can be accurately controlled, change the flow area of fluid, reach the purpose of controlling flow and pressure, realize the control to fluid, the valve has the characteristics of fast response speed, accurate control, with good stability, can keep the stability of fluid parameter in long time running process, improve work efficiency and production benefit, can satisfy the high-speed response requirement of hydraulic system, realize the accurate control to oil cylinder's downlink action.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic control technology, and in particular to a hydraulic control system for a hydraulic cylinder and a hydraulic control system for a heat treatment loading and unloading machine. Background Technology

[0002] The heat treatment loading and unloading machine is a specialized piece of equipment on a heat treatment production line. It features a fork-type structure and is used for loading and unloading free forgings, cast steel parts, ring forgings, and die forgings from the furnace and for quenching. The machine is simple to operate, precise in its movements, and convenient to operate and maintain. It can meet the different heat treatment process requirements of various workpieces, enabling mechanized and automated operation of metal part heat treatment. This effectively improves production efficiency, reduces labor intensity, and minimizes damage to heat-treated workpieces, thus enhancing both efficiency and quality. Its working principle is based on the hydraulic control system of the robotic arm and the adjustment of the workpiece's position within the furnace. Through linkage with other equipment, it achieves full automation of the heat treatment production line.

[0003] During operation, the robotic arm of the heat treatment loading and unloading machine, driven by hydraulic cylinders, first lifts the workpiece and places it into the heating furnace. Electromagnetic induction heating technology is used to rapidly raise the temperature. Once the required temperature is reached, the workpiece is removed, and then, driven by hydraulic cylinders, the robotic arm rapidly lowers the workpiece into the quenching medium, achieving the quenching effect through rapid cooling. However, current hydraulic control systems for heat treatment loading and unloading machines struggle to achieve rapid and precise control during the rapid descent of the workpiece, resulting in ineffective quenching.

[0004] Therefore, a hydraulic control system that can respond quickly and precisely control the downward movement of the workpiece is needed. Utility Model Content

[0005] The purpose of this utility model is to solve the above-mentioned technical problems and provide a hydraulic control system for a hydraulic cylinder and a hydraulic control system for a heat treatment loading and unloading machine. By adopting a two-way cartridge proportional valve, the valve opening can be precisely controlled to change the flow area of ​​the fluid, thereby achieving the purpose of controlling the flow rate and pressure and realizing the control of the fluid. This valve has the characteristics of fast response speed and precise control, and has good stability. It can maintain the stability of fluid parameters during long-term operation, improve work efficiency and production benefits, meet the high-speed response requirements of the hydraulic system, and realize precise control of the downward movement of the hydraulic cylinder.

[0006] To achieve the above objectives, this utility model provides the following solution: This utility model discloses a hydraulic cylinder control system, including an upward cylinder opening and closing valve group, a pressure-holding opening and closing valve group, and a downward cylinder control valve group; the oil inlet of the upward cylinder opening and closing valve group is connected to the oil supply port, the oil outlet of the upward cylinder opening and closing valve group is connected to the oil inlet of the pressure-holding opening and closing valve group, and the oil outlet of the pressure-holding opening and closing valve group is connected to the plug cavity of the cylinder; the downward cylinder control valve group includes a two-way cartridge proportional valve with a pilot valve, the A port of the two-way cartridge proportional valve is connected between the oil outlet of the upward cylinder opening and closing valve group and the oil inlet of the pressure-holding opening and closing valve group, the B port of the two-way cartridge proportional valve is connected to the return port, the X port of the two-way cartridge proportional valve is connected to the oil supply port, the Y port of the two-way cartridge proportional valve is connected to the return port, and the X and Y ports of the two-way cartridge proportional valve are switched by the pilot valve.

[0007] Preferably, the cylinder upward opening and closing valve group includes a first two-way cartridge directional valve, a shuttle valve, and a two-position four-way solenoid directional valve. The A port of the first two-way cartridge directional valve is connected to the oil supply port, the B port of the first two-way cartridge directional valve is connected to the oil inlet of the cylinder pressure holding opening and closing valve group, the P port of the two-position four-way solenoid directional valve is connected to the A port of the first two-way cartridge directional valve, the T port of the two-position four-way solenoid directional valve is connected to the oil return port, the A port of the two-position four-way solenoid directional valve is connected to the A port of the shuttle valve, the B port of the shuttle valve is connected to the B port of the first two-way cartridge directional valve, and the C port of the shuttle valve is connected to the X port of the first two-way cartridge directional valve.

[0008] Preferably, the cylinder pressure-holding opening and closing valve assembly includes a second two-way cartridge directional valve and a two-position three-way solenoid ball valve. The A port of the second two-way cartridge directional valve is connected to the B port of the first two-way cartridge directional valve. The B port of the second two-way cartridge directional valve is connected to the plug cavity of the cylinder. The X port of the second two-way cartridge directional valve is connected to the A port of the two-position three-way solenoid ball valve. The B port of the two-position three-way solenoid ball valve is connected to the plug cavity of the cylinder. The T port of the two-position three-way solenoid ball valve is connected to the return port.

[0009] Preferably, the hydraulic cylinder pressure holding and opening / closing valve assembly further includes a safety valve, the oil inlet of which is connected to port B of the second two-way cartridge directional valve, and the overflow port of which is connected to the return port.

[0010] Preferably, the cylinder downward control valve group further includes a one-way valve, which is connected between the X port of the two-way cartridge proportional valve and the oil supply port.

[0011] Preferably, the cylinder downward control valve group further includes a pressure reducing valve, the oil inlet of the pressure reducing valve is connected between the check valve and the oil supply port, and the overflow port of the pressure reducing valve is connected to the oil return port.

[0012] Preferably, the cylinder downward control valve group further includes an accumulator and a shut-off ball valve, wherein the oil port of the accumulator is connected between the check valve and the X port of the two-way cartridge proportional valve, and the shut-off ball valve is connected between the oil port and the return port of the accumulator.

[0013] Preferably, the shut-off ball valve is a plate-type high-pressure ball valve.

[0014] This utility model also discloses a hydraulic control system for a heat treatment loading and unloading machine, characterized in that it includes a hydraulic cylinder and the aforementioned hydraulic cylinder control system, wherein the cylinder's rod chamber is connected to an oil tank, and the cylinder is used to drive the robotic arm of the heat treatment loading and unloading machine.

[0015] Preferably, it includes three of the aforementioned hydraulic cylinders.

[0016] The present invention achieves the following technical advantages over the prior art:

[0017] This invention employs a two-way cartridge proportional valve, utilizing a proportional regulator to adjust the control signal output from the electric actuator. This adjusts the movement of the main valve core of the two-way cartridge proportional valve, and a displacement sensor of the main valve core provides feedback, which corresponds to the input signal to calibrate the valve opening. This alters the fluid flow area, achieving the goal of controlling flow rate and pressure, thus realizing fluid control. This valve features fast response, precise control, and good stability, maintaining stable fluid parameters during long-term operation, improving work efficiency and production benefits. It can meet the high-speed requirements of hydraulic systems and achieve precise control of the downward movement of the cylinder. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained by analyzing these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the hydraulic control system of the heat treatment loading and unloading machine in this embodiment of the present invention;

[0020] Figure 2 This is a partial structural schematic diagram of the cylinder upward opening and closing valve assembly in an embodiment of this utility model;

[0021] Figure 3 This is a partial structural schematic diagram of the hydraulic cylinder pressure-holding opening and closing valve assembly in an embodiment of this utility model;

[0022] Figure 4 This is a partial structural schematic diagram of the hydraulic cylinder downward control valve assembly in an embodiment of this utility model.

[0023] Explanation of reference numerals in the attached diagram: 1. First two-way cartridge directional valve; 2. Two-position four-way solenoid directional valve; 3. Shuttle valve; 4. Second two-way cartridge directional valve; 5. Two-position three-way solenoid ball valve; 6. Safety valve; 7. Two-way cartridge proportional valve; 8. Pressure reducing valve; 9. Check valve; 10. Accumulator; 11. Shut-off ball valve; 12. Hydraulic cylinder. Detailed Implementation

[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments analyzed and obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0025] The purpose of this invention is to provide a hydraulic control system for a heat treatment loading and unloading machine to solve the problems existing in the prior art. This hydraulic cylinder control system adopts a two-way cartridge proportional valve. A proportional regulator adjusts the control signal output from the electric actuator to control the movement of the main valve core. A displacement sensor of the main valve core provides feedback signals, which correspond to the input signal to calibrate the valve opening, thereby changing the fluid flow area and achieving the purpose of controlling flow rate and pressure. This valve features fast response, precise control, and good stability, maintaining stable fluid parameters during long-term operation, improving work efficiency and production benefits. It can meet the high-speed requirements of hydraulic systems and achieve precise control of mechanical equipment. This hydraulic cylinder control system has a simple structure, low cost, high cost-effectiveness, and is easy to maintain and debug.

[0026] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] Example 1

[0028] like Figures 1 to 4 As shown, this embodiment provides a hydraulic cylinder control system, which can be used for the robotic arm control of a heat treatment loading and unloading machine, and also for the control of other equipment. Its main function is to control the upward and downward movements of the piston rod of the hydraulic cylinder. Specifically, this hydraulic cylinder control system includes an upward on / off valve assembly for the hydraulic cylinder (see reference). Figure 2), hydraulic cylinder pressure holding and opening / closing valve assembly (reference) Figure 3 ) and the cylinder downward control valve assembly (reference) Figure 4 The inlet of the upward-moving valve assembly is connected to the oil supply port, and the outlet of the upward-moving valve assembly is connected to the inlet of the pressure-holding valve assembly. The outlet of the pressure-holding valve assembly is connected to the plug cavity of cylinder 12. The downward-moving control valve assembly includes a two-way cartridge proportional valve 7. Port A of the two-way cartridge proportional valve 7 is connected between the outlet of the upward-moving valve assembly and the inlet of the pressure-holding valve assembly. Port B of the two-way cartridge proportional valve 7 is connected to the return port. Port X of the two-way cartridge proportional valve 7 is connected to the oil supply port, and port Y of the two-way cartridge proportional valve 7 is connected to the return port. The two-way cartridge proportional valve 7 has a pilot valve, and ports X and Y of the two-way cartridge proportional valve 7 are switched through the pilot valve. The return port connected to the Y port of the two-way cartridge proportional valve 7 can be the same return port or two different return ports connected to the B port of the two-way cartridge proportional valve 7. The supply port connected to the X port of the two-way cartridge proportional valve 7 can be the same supply port or two different supply ports connected to the inlet port of the cylinder upward opening and closing valve assembly.

[0029] Working principle:

[0030] ① Cylinder Upward Movement: The cylinder upward opening and closing valve group opens, the cylinder pressure holding opening and closing valve group opens, and the pilot valve of the two-way cartridge proportional valve 7 is de-energized, so ports A and B of the two-way cartridge proportional valve 7 are not connected. The oil output from the delivery pump enters the cylinder hydraulic control system through the oil supply port. The oil will pass through the cylinder upward opening and closing valve group and the cylinder pressure holding opening and closing valve group in sequence into the plug chamber of cylinder 12, pushing the piston rod upward to achieve the upward movement. After rising to the preset position, the system is unloaded, the cylinder upward opening and closing valve group closes, the cylinder pressure holding opening and closing valve group closes, and the piston rod of cylinder 12 remains stationary.

[0031] ② Cylinder Downward Movement: The cylinder upward opening and closing valve group opens, the cylinder pressure holding opening and closing valve group remains closed, and the amplifier provides drive current to the pilot valve of the two-way cartridge proportional valve 7. The pilot valve core moves, realizing reversal. The oil output from the delivery pump flows into the X port of the two-way cartridge proportional valve 7 from the oil supply port. The control oil in the two-way cartridge proportional valve 7 flows out from the Y port and into the oil tank from the return port, controlling the movement of the main valve core. The A and B ports of the two-way cartridge proportional valve 7 are connected. The hydraulic oil in the piston chamber of cylinder 12 passes through the cylinder upward opening and closing valve group and the A and B ports of the two-way cartridge proportional valve 7, and then flows into the oil tank from the return port. Under the gravity of the equipment driven by cylinder 12, the piston rod moves downward, realizing the cylinder downward movement. The displacement sensor in the two-way cartridge proportional valve 7 provides feedback on the position signal of the main valve core. By controlling the flow of hydraulic oil in the X port and adjusting the opening degree of the valve core, the downward movement speed of the piston rod can be precisely controlled.

[0032] This hydraulic cylinder control system employs a two-way cartridge proportional valve 7. A proportional regulator adjusts the control signal output from the electric actuator, controlling the movement of the main valve core. A displacement sensor in the main valve core provides feedback, which, along with the input signal, calibrates the valve opening, thereby altering the fluid flow area to control flow rate and pressure. This valve features fast response, precise control, and excellent stability, maintaining stable fluid parameters during prolonged operation, thus improving work efficiency and production benefits. It can meet the high-speed requirements of hydraulic systems, enabling precise control of mechanical equipment. This hydraulic cylinder control system has a simple structure, low cost, high cost-effectiveness, and is easy to maintain and debug.

[0033] In one embodiment, the pilot valve of the two-way cartridge proportional valve 7 is a proportional pilot valve. Both the main valve core of the two-way cartridge proportional valve 7 and the valve core of the proportional pilot valve are equipped with displacement sensors to perform dual closed-loop control, which can quickly and accurately control the opening size of the main valve core, unaffected by the working conditions, thereby quickly and accurately controlling the movement of the working parts.

[0034] In one embodiment, the cylinder upward opening and closing valve assembly includes a first two-way cartridge directional valve 1, a two-position four-way solenoid directional valve 2, and a shuttle valve 3. The shuttle valve 3 can perform oil circuit distribution and control the oil flow direction. Port A of the first two-way cartridge directional valve 1 is connected to the oil supply port, and port B of the first two-way cartridge directional valve 1 is connected to the oil inlet of the cylinder pressure-holding opening and closing valve assembly. Port P of the two-position four-way solenoid directional valve 2 is connected to port A of the first two-way cartridge directional valve 1, and port T of the two-position four-way solenoid directional valve 2 is connected to the oil return port. Port A of the two-position four-way solenoid directional valve 2 is connected to port A of the shuttle valve 3, port B of the shuttle valve 3 is connected to port B of the first two-way cartridge directional valve 1, and port C of the shuttle valve 3 is connected to port X of the first two-way cartridge directional valve 1. In addition, the two-position four-way solenoid directional valve 2 can be a non-electromagnetically controlled two-position four-way directional valve, such as through pneumatic control or hydraulic control, but it does not have the same response speed as a solenoid valve.

[0035] Working principle:

[0036] When the cylinder moves downward, the two-position four-way solenoid directional valve 2 is de-energized and is in the parallel position. Ports P and A are connected, and ports T and B are connected. After the hydraulic oil enters through the oil supply port, it flows into the X port of the first two-way cartridge directional valve 1 through ports P and A of the two-position four-way solenoid directional valve 2. The valve core remains in the initial closed state. At this time, the hydraulic oil cannot pass through the first two-way cartridge directional valve 1, thus achieving the closure of the cylinder upward opening and closing valve group.

[0037] When the hydraulic cylinder moves upward, the two-position four-way solenoid directional valve 2 is energized and is in the cross position, with ports P and B connected, and ports T and A connected. Oil drains from port X of the first two-way cartridge directional valve 1, flows through ports A and T of the two-position four-way solenoid directional valve 2, to the return port, and then flows into the oil tank. The hydraulic oil entering from the supply port passes through port A of the first two-way cartridge directional valve 1, overcomes the valve core spring pressure, and opens the valve core. Ports A and B of the first two-way cartridge directional valve 1 are connected, realizing the opening of the valve assembly for the upward movement of the hydraulic cylinder.

[0038] The above setting method for the hydraulic cylinder upward opening and closing valve group is a reference method. It can also be improved or other setting methods can be adopted according to needs and actual conditions.

[0039] In one embodiment, the hydraulic cylinder pressure-holding opening and closing valve group includes a second two-way cartridge directional valve 4 and a two-position three-way solenoid ball valve 5. The A port of the second two-way cartridge directional valve 4 is connected to the B port of the first two-way cartridge directional valve 1, the B port of the second two-way cartridge directional valve 4 is connected to the plug cavity of the hydraulic cylinder 12, the X port of the second two-way cartridge directional valve 4 is connected to the A port of the two-position three-way solenoid ball valve 5, the B port of the two-position three-way solenoid ball valve 5 is connected to the plug cavity of the hydraulic cylinder 12, and the T port of the two-position three-way solenoid ball valve 5 is connected to the return oil port.

[0040] Working principle:

[0041] When the cylinder moves upward, the two-position three-way solenoid ball valve 5 is normally de-energized, and ports B and A of the two-position three-way solenoid ball valve 5 are connected. If the hydraulic oil in the plug chamber of the cylinder 12 flows back, it will flow into the X port of the second two-way cartridge directional valve 4 through ports B and A of the two-position three-way solenoid ball valve 5, causing the valve core of the second two-way cartridge directional valve 4 to close. Therefore, at this time, the second two-way cartridge directional valve 4 is in the function of a check valve. After the oil flows from port B of the first two-way cartridge directional valve 1 into port A of the second two-way cartridge directional valve 4, the hydraulic oil overcomes the spring force, the valve core opens, ports A and B are connected, and the oil flows in from port A and out from port B, flowing into the plug chamber of the cylinder 12.

[0042] When the hydraulic cylinder moves downward, the two-position three-way solenoid ball valve 5 is energized, and ports A and T of the two-position three-way solenoid ball valve 5 are open, while port B of the two-position three-way solenoid ball valve 5 is blocked. At this time, the second two-way cartridge directional valve 4 loses its one-way valve function. The hydraulic oil flowing out of the plug chamber of the hydraulic cylinder 12 flows into port B of the second two-way cartridge directional valve 4. The hydraulic oil overcomes the spring force, and the valve core opens. Port X of the second two-way cartridge directional valve 4 is connected to the plug chamber of the hydraulic cylinder 12 through the two-position three-way solenoid ball valve 5. Ports B and A are open, and the oil flows out from port A and into port A of the two-way cartridge proportional valve 7. It then flows from port B of the two-way cartridge proportional valve 7 into the return port and back to the oil tank.

[0043] The setting method of the hydraulic cylinder pressure holding valve assembly can be used as a reference, but it can also be improved or other settings can be adopted according to needs and actual conditions.

[0044] Both the first two-way cartridge directional valve 1 and the second two-way cartridge directional valve 4 are cartridge valves with a seated valve structure, which differs significantly from ordinary spool valves. They include a control cover and cartridge components, and are equipped with a manual adjusting rod to adjust the valve core opening and control the flow rate. They offer numerous advantages: simple structure, flexible design, good controllability, and the ability to withstand large flow rates and high pressures. The diameter of each component in the cartridge valve assembly can be adjusted according to actual conditions to adapt to equipment with different tonnage requirements, resulting in a wider range of applications, stronger adaptability, high reliability, elimination of external leakage and reduction of internal leakage, and good pressure holding performance.

[0045] In one embodiment, the hydraulic cylinder pressure-holding on / off valve assembly further includes a safety valve 6. The inlet of the safety valve 6 is connected to port B of the second two-way cartridge directional valve 4, and the overflow port of the safety valve 6 is connected to the return port. The safety valve 6 mainly prevents accidents caused by overload, thus achieving a safety protection function. When supplying or returning oil, if the oil pressure exceeds the set value of the safety valve 6, the oil will flow through the overflow port into the return port and back to the oil tank.

[0046] In one embodiment, the cylinder downward control valve group further includes a one-way valve 9, which is connected between the X port of the two-way cartridge proportional valve 7 and the oil supply port to prevent oil from flowing back from the X port to the oil supply port.

[0047] In one embodiment, the hydraulic cylinder downward control valve assembly further includes a pressure reducing valve 8. The inlet of the pressure reducing valve 8 is connected between the check valve 9 and the oil supply port, and the overflow port of the pressure reducing valve 8 is connected to the oil return port. When the oil pressure exceeds the set value of the pressure reducing valve 8, it will automatically overflow to relieve pressure. This causes the pressure at the X port of the two-way cartridge proportional valve 7 to be lower than the main system pressure. The pressure reducing valve 8 reduces the pressure, and the check valve 9 enables unidirectional flow of oil in the circuit.

[0048] In one embodiment, the cylinder downward control valve assembly further includes an accumulator 10 and a shut-off ball valve 11. The oil port of the accumulator 10 is connected between the check valve 9 and the X port of the two-way cartridge proportional valve 7, and the shut-off ball valve 11 is connected between the oil port and the return port of the accumulator 10. After the oil flows out of the check valve 9, the oil will be divided into two oil paths. One oil path flows into the X port of the two-way cartridge proportional valve 7, and the other oil path flows into the accumulator 10 for energy storage. The accumulator 10 stores energy to ensure sufficient pressure control at the X port of the two-way cartridge proportional valve 7 when the main system is not working.

[0049] In one embodiment, the shut-off ball valve 11 is a plate-type high-pressure ball valve.

[0050] Example 2

[0051] like Figures 1 to 4As shown, this embodiment provides a hydraulic control system for a heat treatment loading and unloading machine, including a hydraulic cylinder 12 and the hydraulic cylinder control system in Embodiment 1. The rod chamber of the hydraulic cylinder 12 is connected to the oil tank, and the plug chamber of the hydraulic cylinder 12 is connected to the oil outlet of the hydraulic cylinder pressure holding and opening / closing valve assembly. The hydraulic cylinder 12 is used to drive the robotic arm of the heat treatment loading and unloading machine.

[0052] In one embodiment, three hydraulic cylinders 12 are included. The three hydraulic cylinders 12 are responsible for driving the robotic arm to different positions.

[0053] In one embodiment, the complete control process of the hydraulic control system of the heat treatment loading and unloading machine is as follows:

[0054] ① Cylinder Upward Movement: The hydraulic cylinder 12, through a robotic arm structure, moves the workpiece to the corresponding height position, fixes it in place, and then places it in the heat treatment equipment for heating. Specific control process: The two-position four-way solenoid valve 2 is energized, and ports A and B of the first two-way cartridge valve 1 are connected. Hydraulic fluid flows out from port B of the first two-way cartridge valve 1. The two-position three-way solenoid ball valve 5 is normally de-energized, and the second two-way cartridge valve 4 functions as a check valve. After hydraulic fluid flows from port B of the first two-way cartridge valve 1 into port A of the second two-way cartridge valve 4, the hydraulic oil overcomes the spring force, the valve core opens, and ports A and B are connected. Hydraulic fluid flows in from port A and out from port B, flowing into the plug chamber of the hydraulic cylinder 12. The hydraulic fluid entering the plug chamber of the hydraulic cylinder 12 pushes the piston rod upward, achieving the upward movement. After reaching the position, the system is unloaded, all valves return to normal, and the piston rod of the hydraulic cylinder 12 remains stationary.

[0055] The hydraulic cylinder descends as follows: After the workpiece is heated, it needs to be quickly placed into the cooling medium. After the workpiece is removed from the heat treatment equipment, it is quickly lowered and placed into the cooling pool. Specific control process: The two-position four-way solenoid directional valve 2 is de-energized, the first two-way cartridge directional valve 1 is closed, and the two-position three-way solenoid ball valve 5 is energized (the two-position three-way solenoid ball valve 5 has no internal leakage, which can ensure that the cylinder is fixed and prevents it from sliding down). The oil in the plug chamber of the cylinder 12 flows to the two-way cartridge proportional valve 7 through the B and A ports of the second two-way cartridge directional valve 4. The amplifier provides drive current to the pilot valve of the two-way cartridge proportional valve 7, the pilot valve core moves, realizing the reversal. The oil output by the delivery pump flows into the X port of the two-way cartridge proportional valve 7 from the oil supply port. The control oil in the two-way cartridge proportional valve 7 flows out from the Y port, controlling the movement of the main valve core. The A and B ports of the two-way cartridge proportional valve 7 are connected. The hydraulic oil flows into the return port from the A and B ports of the two-way cartridge proportional valve 7, and then into the oil tank. Under the action of the workpiece gravity, the piston rod of the cylinder 12 moves down quickly, realizing the downward action of the cylinder 12. By using the displacement sensor inside the two-way cartridge proportional valve 7 to receive the position signal of the main valve core, and by controlling the flow rate of hydraulic oil in port X to adjust the opening degree of the valve core, precise control of the downward movement speed of the piston rod can be achieved.

[0056] The hydraulic control system of this heat treatment loading and unloading machine can realize fully automatic loading and unloading operations of the rapid quenching furnace. After position control is achieved, the workpiece is driven into the heating furnace and rapidly heated using electromagnetic induction heating technology. Once the required temperature is reached, the workpiece is driven out and then quickly lowered into the quenching medium to achieve the quenching effect through rapid cooling.

[0057] This utility model uses specific examples to illustrate its principles and implementation methods. The above description of the embodiments is only for the purpose of helping to understand the method and core idea of ​​this utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the idea of ​​this utility model. In summary, the content of this specification should not be construed as a limitation of this utility model.

Claims

1. A hydraulic control system for a hydraulic cylinder, characterized in that, The system includes an upward-moving valve assembly, a pressure-holding valve assembly, and a downward-moving control valve assembly. The inlet of the upward-moving valve assembly is connected to the oil supply port, and the outlet of the upward-moving valve assembly is connected to the inlet of the pressure-holding valve assembly. The outlet of the pressure-holding valve assembly is connected to the plug cavity of the cylinder. The downward-moving control valve assembly includes a two-way cartridge proportional valve with a pilot valve. Port A of the two-way cartridge proportional valve is connected between the outlet of the upward-moving valve assembly and the inlet of the pressure-holding valve assembly. Port B of the two-way cartridge proportional valve is connected to the return port. Port X of the two-way cartridge proportional valve is connected to the oil supply port, and port Y of the two-way cartridge proportional valve is connected to the return port. Ports X and Y of the two-way cartridge proportional valve are switched via the pilot valve.

2. The hydraulic control system for the oil cylinder according to claim 1, characterized in that, The cylinder upward opening and closing valve group includes a first two-way cartridge directional valve, a shuttle valve, and a two-position four-way solenoid directional valve. The A port of the first two-way cartridge directional valve is connected to the oil supply port, the B port of the first two-way cartridge directional valve is connected to the oil inlet of the cylinder pressure holding opening and closing valve group, the P port of the two-position four-way solenoid directional valve is connected to the A port of the first two-way cartridge directional valve, the T port of the two-position four-way solenoid directional valve is connected to the oil return port, the A port of the two-position four-way solenoid directional valve is connected to the A port of the shuttle valve, the B port of the shuttle valve is connected to the B port of the first two-way cartridge directional valve, and the C port of the shuttle valve is connected to the X port of the first two-way cartridge directional valve.

3. The hydraulic control system for the oil cylinder according to claim 2, characterized in that, The hydraulic cylinder pressure-holding opening and closing valve assembly includes a second two-way cartridge directional valve and a two-position three-way solenoid ball valve. The A port of the second two-way cartridge directional valve is connected to the B port of the first two-way cartridge directional valve. The B port of the second two-way cartridge directional valve is connected to the plug cavity of the hydraulic cylinder. The X port of the second two-way cartridge directional valve is connected to the A port of the two-position three-way solenoid ball valve. The B port of the two-position three-way solenoid ball valve is connected to the plug cavity of the hydraulic cylinder. The T port of the two-position three-way solenoid ball valve is connected to the return port.

4. The hydraulic control system for the oil cylinder according to claim 3, characterized in that, The hydraulic cylinder pressure holding and opening / closing valve assembly also includes a safety valve. The oil inlet of the safety valve is connected to port B of the second two-way cartridge directional valve, and the overflow port of the safety valve is connected to the return port.

5. The hydraulic control system for the oil cylinder according to claim 1, characterized in that, The cylinder downward control valve group also includes a one-way valve, which is connected between the X port of the two-way cartridge proportional valve and the oil supply port.

6. The hydraulic control system for the oil cylinder according to claim 5, characterized in that, The cylinder downward control valve group also includes a pressure reducing valve, the oil inlet of which is connected between the check valve and the oil supply port, and the overflow port of which is connected to the return port.

7. The hydraulic control system for a hydraulic cylinder according to claim 5 or 6, characterized in that, The cylinder downward control valve group also includes an accumulator and a shut-off ball valve. The oil port of the accumulator is connected between the check valve and the X port of the two-way cartridge proportional valve, and the shut-off ball valve is connected between the oil port and the return port of the accumulator.

8. The hydraulic control system for the oil cylinder according to claim 7, characterized in that, The shut-off ball valve is a plate-type high-pressure ball valve.

9. A hydraulic control system for a heat treatment loading and unloading machine, characterized in that, The system includes a hydraulic cylinder and a hydraulic cylinder control system as described in any one of claims 1-8, wherein the cylinder's rod chamber is connected to an oil tank, and the cylinder is used to drive the robotic arm of a heat treatment loading and unloading machine.

10. The hydraulic control system for the heat treatment loading and unloading machine according to claim 9, characterized in that, It includes the three hydraulic cylinders mentioned above.

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