Quick-closing type linear electro-hydraulic actuator with automatic pressurizing function

Abstract

The invention discloses a quick-closing type linear electro-hydraulic actuator with an automatic pressurizing function. The quick-closing type linear electro-hydraulic actuator comprises an oil tank, a hydraulic control one-way valve, a hydraulic pump, an anti-explosion motor, an overflow valve, a shuttle valve, an anti-explosion pressure sensor, a pressure gauge, an anti-explosion electromagnetic valve, an energy accumulator, a hydraulic lock, a hydraulic oil cylinder and an anti-explosion displacement sensor. The hydraulic system adopts a closed loop, oil is supplemented for flow deviation caused by an asymmetric cylinder through a hydraulic control one-way valve, stretching and retracting of an oil cylinder are achieved by controlling the rotating direction of a motor, a reversing valve does not need to be installed for high-pressure and low-pressure oil way switching, the number of electromagnetic control valves is small, the structure is simple, and control is convenient. The actuator is quickly reset in a power-off state by adopting an energy accumulator oil supply mode, a manual pump or a reset spring does not need to be installed, and the energy accumulator can be automatically pressurized after the pressure of the energy accumulator is reduced. A displacement sensor is installed on the oil cylinder for position feedback, and accurate position control of the oil cylinder can be achieved by adjusting the rotating speed of the motor.

Description

Technical Field

[0001] The invention relates to the field of industrial valve actuators, and in particular to a fast-closing linear electro-hydraulic actuator with an automatic pressure-charging function. Background Art

[0002] The linear electric actuators for industrial valves have relatively low reliability, relatively low adjustment accuracy, long action time, and cannot be closed in emergency situations such as fire and power outages, so their scope of use is also limited. Electro-hydraulic actuators are widely used due to their large output force, stable operation, and high adjustment accuracy, but there are also many problems with electro-hydraulic actuators on the market, which limits the scope of use of electro-hydraulic actuators.

[0003] Most of the electro-hydraulic actuators on the market currently do not have an emergency shutdown function, or use a manual pump for emergency shutdown, or use a spring for emergency shutdown. Electro-hydraulic actuators without an emergency shutdown function cannot be shut down in emergency situations such as fire and power outages, which can easily cause accidents. Electro-hydraulic actuators that use a manual pump for emergency shutdown have a slow shutdown time and cannot meet the needs of rapid shutdown in emergency situations such as fire and power outages. Electro-hydraulic actuators that use spring emergency shutdowns cannot meet the market's demand for miniaturization and diversification of electro-hydraulic actuators due to their large size and fixed installation method. Therefore, the market is in urgent need of a simple way to achieve the emergency shutdown function of electro-hydraulic actuators.

[0004] After the emergency shutdown of the actuator is performed using the accumulator to supply oil, the accumulator pressure will decrease, and the accumulator is usually manually charged. In addition, due to leakage of the slide valve or internal pipeline, the accumulator will also experience pressure drop after being stored for a long time. It is necessary to regularly check the accumulator pressure and charge it.

[0005] Linear electro-hydraulic actuators mostly use reversing valve switching to control the extension and retraction of the actuator. In explosion-proof scenarios, explosion-proof solenoid valves are required, which increases the weight and volume of the electro-hydraulic actuator, increases the number of explosion-proof electrical components and control ports, and reduces the reliability of the electro-hydraulic actuator. Summary of the invention

[0006] In view of the shortcomings of the prior art, the present invention provides a fast-closing linear electro-hydraulic actuator with an automatic pressure-charging function, which has the characteristics of high safety, high reliability and high cost performance. The purpose of the present invention is achieved through the following technical solutions:

[0007] The technical solution adopted by the present invention is as follows:

[0008] A fast-closing linear electro-hydraulic actuator with an automatic pressurization function, comprising an oil tank, a hydraulically controlled one-way valve 1, a hydraulically controlled one-way valve 2, a hydraulic pump, an explosion-proof motor, a relief valve 1, a relief valve 2, a shuttle valve, an explosion-proof pressure sensor 1, an explosion-proof pressure sensor 2, a pressure gauge, an explosion-proof solenoid valve 1, an explosion-proof solenoid valve 2, an accumulator, a two-way hydraulic lock, a hydraulic cylinder and an explosion-proof displacement sensor;

[0009] The explosion-proof motor drives the hydraulic pump, which is a bidirectional hydraulic pump, including a left oil port and a right oil port, and realizes oil discharge on the left side and oil suction or oil return on the right side when the explosion-proof motor is driven forward and reversely, or oil discharge on the right side and oil suction or oil return on the left side;

[0010] The two oil ports of the hydraulically controlled one-way valve 1 are respectively connected to the right oil port of the hydraulic pump and the oil tank, and the control port of the hydraulically controlled one-way valve 1 is connected to the left oil port of the hydraulic pump; the two oil ports of the hydraulically controlled one-way valve 2 are connected to the left oil port of the hydraulic pump and the oil tank, and the control port of the hydraulically controlled one-way valve 2 is connected to the right oil port of the hydraulic pump, so as to realize the oil tank replenishing oil to the oil ports on both sides of the hydraulic pump;

[0011] The inlet of the relief valve 1 is connected to the left oil port of the hydraulic pump, and the outlet of the relief valve 1 is connected to the oil tank, so as to limit the large chamber circuit pressure of the hydraulic cylinder; the inlet of the relief valve 2 is connected to the right oil port of the hydraulic pump, and the outlet of the relief valve 2 is connected to the oil tank, so as to limit the small chamber circuit pressure of the hydraulic cylinder;

[0012] The two inlets of the shuttle valve are respectively connected to the oil ports on both sides of the hydraulic pump to lead out the high pressure on both sides of the hydraulic pump, and the outlet of the shuttle valve is connected to the explosion-proof pressure sensor 1 and the pressure gauge to feedback and display the system pressure;

[0013] The explosion-proof solenoid valve 1 and the explosion-proof solenoid valve 2 are both two-position two-way reversing valves. The two ports of the explosion-proof solenoid valve 1 are respectively connected to the left oil port of the hydraulic pump and the oil port of the accumulator. In the case of power failure, the oil port of the accumulator is connected to the left oil port of the hydraulic pump, and in the case of power, the oil port of the accumulator is cut off and disconnected from the left oil port of the hydraulic pump; one port of the explosion-proof solenoid valve 2 is connected to the left oil port of the hydraulic pump and the outlet of the explosion-proof solenoid valve, and the other port is connected to the left one-way valve oil port of the two-way hydraulic lock. In the case of power failure, the two-way hydraulic lock is connected to the left oil port of the hydraulic pump, and in the case of power, the two-way hydraulic lock is cut off and disconnected from the left oil port of the hydraulic pump;

[0014] The oil port of the accumulator is also equipped with the second explosion-proof pressure sensor for measuring and feeding back the pressure of the accumulator;

[0015] The bidirectional hydraulic lock is connected to the oil ports on both sides of the hydraulic pump and the two chambers of the hydraulic cylinder to achieve position locking of the hydraulic cylinder;

[0016] The hydraulic cylinder is a single-rod asymmetric piston cylinder, on which the explosion-proof displacement sensor is installed to provide real-time feedback on the cylinder position and achieve precise position control of the cylinder.

[0017] Furthermore, the explosion-proof motor is a servo motor or a speed-regulating motor with a brake, and has forward and reverse rotation and variable speed functions; the oil tank is a rectangular closed oil tank.

[0018] Furthermore, the relief valve 1 and the relief valve 2 are both plug-in manually adjustable relief valves.

[0019] Furthermore, the accumulator is a diaphragm accumulator that can be repeatedly filled with oil and discharged with oil.

[0020] Furthermore, when the explosion-proof pressure sensor 2 detects that the pressure of the accumulator is lower than the set pressure, when the hydraulic cylinder does not need to move, the system automatically switches to the oil filling state and automatically charges the accumulator. The specific oil filling control process is as follows:

[0021] The explosion-proof solenoid valve 1 is powered off and is in the on position, the explosion-proof solenoid valve 2 is powered on and is in the off position, the explosion-proof motor rotates clockwise, the right oil port of the hydraulic pump draws oil from the oil tank through the hydraulically controlled one-way valve, and the left oil port of the hydraulic pump discharges high-pressure oil, which enters the accumulator through the explosion-proof solenoid valve to charge it. The charging pressure is set by the relief valve 1. When the set pressure is reached, the relief valve starts to overflow. After the explosion-proof pressure sensor 2 detects that the accumulator has reached the pressure, the motor stops, and the charging is completed; the explosion-proof solenoid valve 1 is switched to the powered state, and the explosion-proof solenoid valve 2 is powered off.

[0022] Furthermore, the oil circuit control process of the hydraulic cylinder piston rod retracting action is:

[0023] The explosion-proof motor rotates counterclockwise, and the right side of the hydraulic pump is a high-pressure oil discharge port. The oil enters the small chamber of the hydraulic cylinder through the right-side one-way valve in the two-way hydraulic lock, and the high-pressure oil enters the left control chamber of the two-way hydraulic lock, opening the left-side one-way valve of the two-way hydraulic lock. The large chamber circuit of the hydraulic cylinder is connected, and the high-pressure oil pushes the piston rod to retract. The low-pressure oil in the large chamber of the cylinder enters the left oil port of the hydraulic pump through the second explosion-proof solenoid valve. Since the hydraulic cylinder is a single-rod asymmetric piston cylinder, the low-pressure oil discharged from the large chamber is more than the oil inlet of the small chamber. The high-pressure oil on the right side of the hydraulic pump has opened the second hydraulic control one-way valve, and the excess large chamber return oil returns to the oil tank through the second hydraulic control one-way valve; when the pressure of the high-pressure circuit on the right side reaches the pressure set by the second overflow valve, a part of the high-pressure oil on the right side overflows back through the second overflow valve.

[0024] Furthermore, the oil circuit control process when the piston rod of the hydraulic cylinder is retracted into position is as follows:

[0025] The explosion-proof motor continues to rotate counterclockwise. Since the hydraulic cylinder has retracted into place, the high-pressure oil no longer enters the small cylinder chamber of the hydraulic cylinder, and directly overflows and returns the oil through the second overflow valve; no return oil is discharged from the large cylinder chamber of the hydraulic cylinder, and the left oil port of the hydraulic pump draws oil from the oil tank through the second hydraulically controlled one-way valve.

[0026] Furthermore, the oil circuit control process under the extension action of the piston rod of the hydraulic cylinder is as follows: the explosion-proof motor rotates clockwise, the left side of the hydraulic pump is the high-pressure oil discharge port, the oil enters the large chamber of the hydraulic cylinder through the explosion-proof solenoid valve and the left-side one-way valve in the two-way hydraulic lock, and at the same time, the high-pressure oil enters the right control chamber of the two-way hydraulic lock, opens the right-side one-way valve of the two-way hydraulic lock, and the small chamber circuit of the hydraulic cylinder is connected, the high-pressure oil pushes the piston rod to extend, and the low-pressure oil in the small chamber of the hydraulic cylinder enters the right oil port of the hydraulic pump. Since the hydraulic cylinder is a single-rod asymmetric piston cylinder, the low-pressure oil discharged from the small chamber is less than the oil inlet of the large chamber, and the oil tank replenishes oil to the right suction port of the hydraulic pump through the hydraulic control one-way valve; when the pressure of the left high-pressure circuit reaches the set pressure of the overflow valve, a part of the left high-pressure oil overflows back through the overflow valve.

[0027] Furthermore, the oil circuit control process when the piston rod of the hydraulic cylinder is in the fully extended state is as follows: the explosion-proof motor continues to rotate clockwise, and since the hydraulic cylinder has been fully extended, the high-pressure oil no longer enters the large cylinder chamber of the hydraulic cylinder, and directly overflows and returns the oil through the overflow valve 1; there is no return oil discharged from the small cylinder chamber of the hydraulic cylinder, and the right oil port of the hydraulic pump draws oil from the oil tank through the hydraulically controlled one-way valve 1.

[0028] Furthermore, when the actuator loses power suddenly, the oil circuit control process is as follows: the explosion-proof motor is powered off and the brake is engaged, the hydraulic pump stops and is locked, the explosion-proof solenoid valve 1 is powered off and is in the on position, and the high-pressure oil in the accumulator enters the large chamber of the hydraulic cylinder through the explosion-proof solenoid valve 1 and the explosion-proof solenoid valve 2 and the left-side one-way valve in the two-way hydraulic lock. At the same time, the high-pressure oil enters the right-side control chamber of the two-way hydraulic lock, opens the right-side one-way valve of the two-way hydraulic lock, and the small chamber circuit of the hydraulic cylinder is connected, and the high-pressure oil pushes the piston rod to extend quickly, closing the actuator urgently; the high-pressure oil in the accumulator has pressed the hydraulically controlled one-way valve 1, and the return oil from the small chamber of the oil cylinder returns to the oil tank through the hydraulically controlled one-way valve 1.

[0029] The beneficial effects of the present invention are as follows:

[0030] 1. The present invention realizes the extension and retraction of the oil cylinder by controlling the rotation direction of the motor, and there is no need to install a reversing valve to switch the high and low pressure oil circuits. The number of electromagnetic control valves is small, the structure is simple, and the control is convenient.

[0031] 2. The present invention uses an accumulator to supply oil to quickly reset the actuator in a power-off state, without the need to install a manual pump or a reset spring.

[0032] 3. A displacement sensor is installed on the oil cylinder of the present invention for position feedback, and accurate position control of the oil cylinder can be achieved by adjusting the motor speed.

[0033] 4. The present invention adopts a hydraulically controlled one-way valve to replenish oil to solve the problem of less oil return in the small cavity of the asymmetric cylinder in the closed circuit. The cylinder is a single-rod cylinder and the actuator is relatively small.

[0034] 5. The present invention detects the accumulator pressure through a pressure sensor, and can automatically charge the accumulator through a pressure compensation circuit after the accumulator pressure drops. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the hydraulic principle of a fast-closing linear electro-hydraulic actuator with an automatic pressurization function according to an embodiment of the present invention.

[0036] Figure 2 It is a schematic diagram of the oil circuit of the accumulator in the oil-filled state according to an embodiment of the present invention.

[0037] Figure 3 It is a schematic diagram of the oil circuit under the retraction action of the piston rod of the hydraulic cylinder according to an embodiment of the present invention.

[0038] Figure 4 It is a schematic diagram of the oil circuit when the piston rod of the hydraulic oil cylinder according to an embodiment of the present invention is retracted into position.

[0039] Figure 5 It is a schematic diagram of the oil circuit under the extension action of the piston rod of the hydraulic oil cylinder according to an embodiment of the present invention.

[0040] Figure 6 It is a schematic diagram of the oil circuit when the piston rod of the hydraulic oil cylinder according to an embodiment of the present invention is in the state of being fully extended.

[0041] Figure 7 It is a schematic diagram of the oil circuit when the actuator is in a fast closing state during a power failure in an embodiment of the present invention.

[0042] In the figure, 1 is an oil tank, 2-1 is a hydraulically controlled one-way valve 1, 2-2 is a hydraulically controlled one-way valve 2, 3 is a hydraulic pump, 4 is an explosion-proof motor, 5-1 is an overflow valve 1, 5-2 is an overflow valve 2, 6 is a shuttle valve, 7-1 is an explosion-proof pressure sensor 1, 7-2 is an explosion-proof pressure sensor 2, 8 is a pressure gauge, 9-1 is an explosion-proof solenoid valve 1, 9-2 is an explosion-proof solenoid valve 2, 10 is an accumulator, 11 is a hydraulic lock, 12 is a hydraulic cylinder, and 13 is an explosion-proof displacement sensor. DETAILED DESCRIPTION

[0043] The present invention will be described in detail below based on the accompanying drawings and preferred embodiments, and the purpose and effects of the present invention will become more clear. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0044] like Figure 1 As shown, the fast-closing linear electro-hydraulic actuator with automatic pressurization function of this embodiment includes an oil tank 1, a hydraulically controlled one-way valve 2-1, a hydraulically controlled one-way valve 2-2, a hydraulic pump 3, an explosion-proof motor 4, an overflow valve 5-1, an overflow valve 5-2, a shuttle valve 6, an explosion-proof pressure sensor 7-1, an explosion-proof pressure sensor 7-2, a pressure gauge 8, an explosion-proof solenoid valve 9-1, an explosion-proof solenoid valve 9-2, an accumulator 10, a two-way hydraulic lock 11, a hydraulic cylinder 12 and an explosion-proof displacement sensor 13.

[0045] The hydraulic pump 3 is a bidirectional hydraulic pump with oil ports on the left and right sides. When the explosion-proof motor 4 rotates clockwise, the left oil port is a high-pressure oil outlet port, and the right oil port is an oil suction port and an oil return port. When the explosion-proof motor 4 rotates counterclockwise, the right oil port is a high-pressure oil outlet port, and the left oil port is an oil suction port and an oil return port.

[0046] The two oil ports of hydraulic control check valve 1 2-1 are connected to the right oil port of hydraulic pump 3 and oil tank 1 respectively, and the control port of hydraulic control check valve 1 2-1 is connected to the left oil port of hydraulic pump 3; the two oil ports of hydraulic control check valve 2 2-2 are connected to the left oil port of hydraulic pump 3 and oil tank 1, and the control port of hydraulic control check valve 2 2-2 is connected to the right oil port of hydraulic pump 3. When the right oil port of hydraulic pump 3 is the suction port, oil can be replenished through hydraulic control check valve 1 2-1, and hydraulic control check valve 2 2-2 can block the left high-pressure port from returning oil to oil tank 1. When the left circuit of hydraulic cylinder 12 is high pressure, the right circuit of hydraulic cylinder 12 can return oil through hydraulic control check valve 1 2-1.

[0047] The relief valve 1 5-1 and the relief valve 2 5-2 are both plug-in manually adjustable relief valves, wherein the inlet of the relief valve 1 5-1 is connected to the left oil port of the hydraulic pump 3, and the outlet is connected to the oil tank 1, which is used to control the circuit pressure of the large cavity of the hydraulic cylinder 12 and the left oil port of the hydraulic pump 3; the inlet of the relief valve 2 5-2 is connected to the right oil port of the hydraulic pump 3, and the outlet is connected to the oil tank 1, which is used to limit the circuit pressure of the small cavity of the hydraulic cylinder 12 and the right oil port of the hydraulic pump 3. When the relief valve 1 5-1 and the relief valve 2 5-2 are set to a higher pressure, they can also be used as safety valves.

[0048] The two inlets of the shuttle valve 6 are respectively connected to the oil ports on both sides of the hydraulic pump 3, leading out the high pressure on both sides of the hydraulic pump 3, and connected to the explosion-proof pressure sensor 7-1 and the pressure gauge 8 to feedback and display the system pressure.

[0049] The accumulator 10 is a diaphragm accumulator, which can be repeatedly filled and drained, and the filling pressure is set by the relief valve 5-1.

[0050] The explosion-proof pressure sensor 7 - 2 is installed at the outlet of the accumulator 10 and is used to measure and feedback the pressure of the accumulator 10 .

[0051] The explosion-proof solenoid valve 9-1 is a two-position, two-way reversing valve, and its two ports are respectively connected to the left oil port of the hydraulic pump 3 and the oil port of the accumulator 10. When the power is off, the outlet of the accumulator 10 is connected to the left oil port of the hydraulic pump 3, and when the power is on, the outlet of the accumulator 10 is cut off and disconnected from the left oil port of the hydraulic pump 3.

[0052] The explosion-proof solenoid valve 9-2 is a two-position, two-way reversing valve, one port of which is connected to the left oil port of the hydraulic pump 3 and the outlet of the explosion-proof solenoid valve 9-1, and the other port is connected to the left one-way valve oil port of the two-way hydraulic lock 11. In the case of power failure, the two-way hydraulic lock 11 is connected to the left oil port of the hydraulic pump 3, and in the case of power, the two-way hydraulic lock 11 is cut off and disconnected from the left oil port of the hydraulic pump 3.

[0053] The bidirectional hydraulic lock 11 is connected to the oil ports on both sides of the hydraulic pump 3 and the two chambers of the hydraulic cylinder 12 , so as to realize the position locking of the hydraulic cylinder 12 in two directions.

[0054] The hydraulic cylinder 12 is a single-rod asymmetric piston cylinder, and is equipped with an explosion-proof displacement sensor 13, which can provide real-time feedback on the cylinder position and achieve precise position control of the cylinder.

[0055] The oil tank 1 is a rectangular closed oil tank, and the oil tanks shown in the figure are all the same oil tank.

[0056] The fast-closing linear electro-hydraulic actuator with automatic charging function provided in an embodiment of the present invention can automatically switch to the oil charging state to automatically charge the accumulator after the explosion-proof pressure sensor 7-2 detects that the pressure of the accumulator 10 is lower than the set pressure and the hydraulic cylinder 12 does not need to move.

[0057] The oil circuit diagram of the fast-closing linear electro-hydraulic actuator with automatic pressure-charging function provided by the embodiment of the present invention when the accumulator 10 is filled with oil is as follows: Figure 2 As shown: the explosion-proof solenoid valve 9-1 is in the conduction position when it is powered off, the explosion-proof solenoid valve 9-2 is in the disconnected position when it is powered on, the explosion-proof motor 4 rotates clockwise, the right oil port of the hydraulic pump 3 sucks oil from the oil tank 1 through the hydraulic control check valve 2-1, and the left oil port of the hydraulic pump 3 discharges high-pressure oil, which enters the accumulator 10 through the explosion-proof solenoid valve 9-1 to charge it. The charging pressure is set by the relief valve 5-1. When the set pressure is reached, the relief valve 5-1 begins to overflow. The explosion-proof pressure sensor 7-2 detects that the accumulator 10 has reached the pressure and the motor stops, and the charging is completed. The explosion-proof solenoid valve 9-1 is switched to the powered state, and the explosion-proof solenoid valve 9-2 is powered off. Except when the accumulator 10 is charged with oil, the explosion-proof solenoid valve 9-2 remains powered off.

[0058] The oil circuit diagram of the fast-closing linear electro-hydraulic actuator with automatic pressure-charging function provided by the embodiment of the present invention when the piston rod is retracted is as follows: Figure 3 As shown: the explosion-proof motor 4 rotates counterclockwise, the right side of the hydraulic pump 3 is the high-pressure oil discharge port, the oil enters the small chamber of the hydraulic cylinder 12 through the right-side check valve in the two-way hydraulic lock 11, and the high-pressure oil enters the left control chamber of the two-way hydraulic lock 11 at the same time, the left-side check valve of the hydraulic lock 11 is opened, the large chamber circuit of the hydraulic cylinder 12 is connected, the high-pressure oil pushes the piston rod to retract, and the low-pressure oil in the large chamber of the oil cylinder enters the left suction port of the hydraulic pump 3 through the explosion-proof solenoid valve 29-2. Since the hydraulic cylinder 12 is an asymmetric cylinder, the low-pressure oil discharged from the large chamber is more than the oil intake of the small chamber. The high-pressure oil on the right side of the hydraulic pump 3 has opened the hydraulic control check valve 22-2, and the excess large chamber return oil can be returned to the oil tank 1 through the hydraulic control check valve 22-2. When the pressure of the high-pressure circuit on the right side reaches the pressure set by the overflow valve 25-2, part of the high-pressure oil on the right side overflows and returns through the overflow valve 25-2.

[0059] The oil circuit diagram of the fast-closing linear electro-hydraulic actuator with automatic pressure-charging function provided by the embodiment of the present invention is as follows when the piston rod of the hydraulic cylinder 12 is retracted to the position: Figure 4 As shown: the explosion-proof motor 4 rotates counterclockwise, the right side of the hydraulic pump 3 is the high-pressure oil discharge port, and since the hydraulic cylinder 11 has retracted into place, the high-pressure oil no longer enters the small chamber of the cylinder, and directly overflows and returns the oil through the overflow valve 2 5-2. The system pressure is the set pressure of the overflow valve 2 5-2, and there is no return oil discharged from the large chamber of the cylinder. The left suction port of the hydraulic pump 3 draws oil from the oil tank 1 through the hydraulically controlled one-way valve 2-2.

[0060] The oil circuit diagram of the fast-closing linear electro-hydraulic actuator with automatic pressure-charging function provided by the embodiment of the present invention is as follows: Figure 5As shown: the explosion-proof motor 4 rotates clockwise, the left side of the hydraulic pump 3 is the high-pressure oil discharge port, the oil enters the large chamber of the hydraulic cylinder 12 through the explosion-proof solenoid valve 9-2 and the left one-way valve in the two-way hydraulic lock 11, and the high-pressure oil enters the right control chamber of the two-way hydraulic lock 11 at the same time, the one-way valve on the right side of the hydraulic lock 11 is opened, the small chamber circuit of the hydraulic cylinder is connected, the high-pressure oil pushes the piston rod to extend, and the low-pressure oil in the small chamber of the cylinder enters the right suction port of the hydraulic pump 3. Since the hydraulic cylinder 12 is an asymmetric cylinder, the low-pressure oil discharged from the small chamber is less than the oil inlet of the large chamber, and the oil tank 1 can replenish oil to the right suction port of the hydraulic pump 3 through the hydraulic control one-way valve 2-1. When the pressure of the left high-pressure circuit reaches the pressure set by the overflow valve 5-1, part of the left high-pressure oil overflows back through the overflow valve 5-1.

[0061] The oil circuit diagram of the fast-closing linear electro-hydraulic actuator with automatic pressure-charging function provided by the embodiment of the present invention is as follows when the piston rod of the hydraulic cylinder is in the extended position: Figure 6 As shown: the explosion-proof motor 4 rotates clockwise, the left side of the hydraulic pump 3 is the high-pressure oil discharge port, and because the hydraulic cylinder 11 has been extended into place, the high-pressure oil no longer enters the large chamber of the cylinder, and directly overflows and returns the oil through the relief valve 5-1. The system pressure is the set pressure of the relief valve 5-1, and there is no return oil discharged from the small chamber of the cylinder. The right side oil suction port of the hydraulic pump 3 sucks oil from the oil tank 1 through the hydraulically controlled one-way valve 2-1.

[0062] The oil circuit diagram of the fast-closing linear electro-hydraulic actuator with automatic pressure-charging function provided by the embodiment of the present invention in the fast-closing state of the actuator is as follows: Figure 7 As shown: when the actuator loses power due to an emergency, the explosion-proof motor 4 is powered off and the brake is engaged, the hydraulic pump 3 stops and locks, the explosion-proof solenoid valve 9-1 is powered off and is in the on position, and the high-pressure oil in the accumulator 10 enters the large chamber of the hydraulic cylinder 12 through the explosion-proof solenoid valve 9-1 and the explosion-proof solenoid valve 9-2, and the left one-way valve in the two-way hydraulic lock 11. At the same time, the high-pressure oil enters the right control chamber of the two-way hydraulic lock 11, opens the one-way valve on the right side of the hydraulic lock 11, and the small chamber circuit of the hydraulic cylinder is connected. The high-pressure oil pushes the piston rod to extend quickly, and the actuator is urgently closed. The high-pressure oil at the outlet of the accumulator 10 has opened the hydraulic control one-way valve 2-1, and the return oil from the small chamber of the cylinder can return to the oil tank 1 through the hydraulic control one-way valve 2-1.

[0063] The fast-closing linear electro-hydraulic actuator with automatic charging function of the present invention can control the direction of the actuator by means of motor reversing, is simple to control, does not need to install a large number of electromagnetic reversing valves, and has an emergency shut-off function. It can automatically charge after the accumulator loses pressure without manual charging.

[0064] Those skilled in the art can understand that the above are only preferred examples of the invention and are not intended to limit the invention. Although the invention is described in detail with reference to the above examples, those skilled in the art can still modify the technical solutions recorded in the above examples or replace some of the technical features therein with equivalents. Any modification, equivalent replacement, etc. made within the spirit and principle of the invention shall be included in the protection scope of the invention.

Claims

1. A fast-closing linear electro-hydraulic actuator with automatic pressure-charging function, characterized in that: It comprises an oil tank (1), a hydraulically controlled one-way valve (2-1), a hydraulically controlled one-way valve (2-2), a hydraulic pump (3), an explosion-proof motor (4), a relief valve (5-1), a relief valve (5-2), a shuttle valve (6), an explosion-proof pressure sensor (7-1), an explosion-proof pressure sensor (7-2), a pressure gauge (8), an explosion-proof solenoid valve (9-1), an explosion-proof solenoid valve (9-2), an accumulator (10), a two-way hydraulic lock (11), a hydraulic cylinder (12) and an explosion-proof displacement sensor (13); The explosion-proof motor (4) drives the hydraulic pump (3), and the hydraulic pump (3) is a bidirectional hydraulic pump, including a left oil port and a right oil port, and when the explosion-proof motor (4) is driven forward or reversely, oil is discharged from the left side and oil is sucked or returned from the right side, or oil is discharged from the right side and oil is sucked or returned from the left side; The two oil ports of the hydraulically controlled one-way valve (2-1) are respectively connected to the right oil port of the hydraulic pump (3) and the oil tank (1), and the control port of the hydraulically controlled one-way valve (2-1) is connected to the left oil port of the hydraulic pump (3); the two oil ports of the hydraulically controlled one-way valve (2-2) are connected to the left oil port of the hydraulic pump (3) and the oil tank (1), and the control port of the hydraulically controlled one-way valve (2-2) is connected to the right oil port of the hydraulic pump (3), so as to realize the oil tank (1) replenishing oil to the oil ports on both sides of the hydraulic pump (3); The inlet of the overflow valve 1 (5-1) is connected to the left oil port of the hydraulic pump (3), and the outlet of the overflow valve 1 (5-1) is connected to the oil tank (1), so as to limit the large chamber circuit pressure of the hydraulic cylinder (12); the inlet of the overflow valve 2 (5-2) is connected to the right oil port of the hydraulic pump (3), and the outlet of the overflow valve 2 (5-2) is connected to the oil tank (1), so as to limit the small chamber circuit pressure of the hydraulic cylinder (12); The two inlets of the shuttle valve (6) are respectively connected to the oil ports on both sides of the hydraulic pump (3) to lead out the high pressure on both sides of the hydraulic pump (3); the outlet of the shuttle valve (6) is connected to the explosion-proof pressure sensor 1 (7-1) and the pressure gauge (8) to feedback and display the system pressure; The explosion-proof solenoid valve 1 (9-1) and the explosion-proof solenoid valve 2 (9-2) are both two-position two-way reversing valves. The two ports of the explosion-proof solenoid valve 1 (9-1) are respectively connected to the left oil port of the hydraulic pump (3) and the oil port of the accumulator (10). In the case of power failure, the oil port of the accumulator (10) is connected to the left oil port of the hydraulic pump (3). In the case of power on, the oil port of the accumulator (10) is cut off from the left oil port of the hydraulic pump (3). One port of the explosion-proof solenoid valve 2 (9-2) is connected to the left oil port of the hydraulic pump (3) and the outlet of the explosion-proof solenoid valve (9-1), and the other port is connected to the left check valve oil port of the two-way hydraulic lock (11). In the case of power failure, the two-way hydraulic lock (11) is connected to the left oil port of the hydraulic pump (3). In the case of power on, the two-way hydraulic lock (11) is cut off from the left oil port of the hydraulic pump (3). The oil port of the accumulator (10) is also equipped with the second explosion-proof pressure sensor (7-2) for measuring and feeding back the pressure of the accumulator (10); The bidirectional hydraulic lock (11) is connected to the oil ports on both sides of the hydraulic pump (3) and the two chambers of the hydraulic cylinder (12) to achieve position locking of the hydraulic cylinder (12); The hydraulic cylinder (12) is a single-rod asymmetric piston cylinder, on which the explosion-proof displacement sensor (13) is installed for providing real-time feedback on the cylinder position, thereby achieving precise position control of the cylinder.

2. The fast-closing linear electro-hydraulic actuator with automatic pressure-charging function according to claim 1, characterized in that: The explosion-proof motor (4) is a servo motor or a speed-regulating motor with a brake, and has forward and reverse rotation and speed-changing functions; the oil tank (1) is a rectangular closed oil tank.

3. The fast-closing linear electro-hydraulic actuator with automatic pressure-charging function according to claim 1, characterized in that: The overflow valve 1 (5-1) and the overflow valve 2 (5-2) are both plug-in manually adjustable overflow valves.

4. The fast-closing linear electro-hydraulic actuator with automatic pressure-charging function according to claim 1, characterized in that: The accumulator (10) is a diaphragm accumulator and can be repeatedly filled with oil and discharged with oil.

5. The fast-closing linear electro-hydraulic actuator with automatic pressure-charging function according to claim 1, characterized in that: When the explosion-proof pressure sensor 2 (7-2) detects that the pressure of the accumulator (10) is lower than the set pressure, and when the hydraulic cylinder (12) does not need to act, the system automatically switches to the oil filling state and automatically charges the accumulator. The specific oil filling control process is as follows: The explosion-proof solenoid valve (9-1) is powered off and in the conducting position, the explosion-proof solenoid valve (9-2) is powered on and in the disconnected position, the explosion-proof motor (4) rotates clockwise, the right oil port of the hydraulic pump (3) sucks oil from the oil tank (1) through the hydraulically controlled one-way valve (2-1), and the left oil port of the hydraulic pump (3) discharges high-pressure oil, which enters the accumulator (10) through the explosion-proof solenoid valve (9-1) to charge the accumulator. The charging pressure is set by the overflow valve (5-1). When the set pressure is reached, the overflow valve (5-1) starts to overflow. The explosion-proof pressure sensor (7-2) detects that the accumulator (10) has reached the pressure and the motor stops rotating, and the charging is completed. The explosion-proof solenoid valve (9-1) is switched to the powered state, and the explosion-proof solenoid valve (9-2) is powered off.

6. The fast-closing linear electro-hydraulic actuator with automatic pressure-charging function according to claim 5, characterized in that: The oil circuit control process of the hydraulic cylinder (12) during the piston rod retraction action is as follows: The explosion-proof motor (4) rotates counterclockwise, the right side of the hydraulic pump (3) is a high-pressure oil discharge port, and the oil enters the small chamber of the hydraulic cylinder (12) through the right-side one-way valve in the two-way hydraulic lock (11). At the same time, the high-pressure oil enters the left-side control chamber of the two-way hydraulic lock (11), opens the left-side one-way valve of the two-way hydraulic lock (11), and the large chamber circuit of the hydraulic cylinder (12) is connected. The high-pressure oil pushes the piston rod to retract, and the low-pressure oil in the large chamber of the cylinder enters the explosion-proof solenoid valve (9-2) through the second explosion-proof solenoid valve (9-2). The left oil port of the hydraulic pump (3) is a single-rod asymmetric piston cylinder, and the low-pressure oil discharged from the large chamber is greater than the oil intake of the small chamber. The high-pressure oil on the right side of the hydraulic pump (3) has opened the hydraulically controlled one-way valve (2-2), and the excess large chamber return oil returns to the oil tank (1) through the hydraulically controlled one-way valve (2-2); when the pressure of the high-pressure circuit on the right side reaches the pressure set by the overflow valve (5-2), a part of the high-pressure oil on the right side overflows and returns to the oil through the overflow valve (5-2).

7. The fast-closing linear electro-hydraulic actuator with automatic pressure-charging function according to claim 6, characterized in that: The oil circuit control process when the piston rod of the hydraulic cylinder (12) is retracted into position is as follows: The explosion-proof motor (4) continues to rotate counterclockwise. Since the hydraulic cylinder (12) has retracted to its full position, the high-pressure oil no longer enters the small cylinder chamber of the hydraulic cylinder (12) and directly overflows and returns the oil through the second overflow valve (5-2). No return oil is discharged from the large cylinder chamber of the hydraulic cylinder (12), and the left oil port of the hydraulic pump (3) draws oil from the oil tank (1) through the second hydraulic control check valve (2-2).

8. The fast-closing linear electro-hydraulic actuator with automatic pressure-charging function according to claim 7, characterized in that: The oil circuit control process of the piston rod extension action of the hydraulic oil cylinder (12) is as follows: the explosion-proof motor (4) rotates clockwise, the left side of the hydraulic pump (3) is a high-pressure oil discharge port, the oil enters the large chamber of the hydraulic oil cylinder (12) through the explosion-proof solenoid valve (9-2) and the left-side check valve in the two-way hydraulic lock (11), and at the same time, the high-pressure oil enters the right-side control chamber of the two-way hydraulic lock (11), opens the right-side check valve of the two-way hydraulic lock (11), and the small chamber circuit of the hydraulic oil cylinder (12) is connected. The high-pressure oil pushes the piston rod to extend, and the low-pressure oil in the small chamber of the hydraulic cylinder (12) enters the right oil port of the hydraulic pump (3). Since the hydraulic cylinder (12) is a single-rod asymmetric piston cylinder, the low-pressure oil discharged from the small chamber is less than the oil intake of the large chamber, and the oil tank (1) replenishes oil to the right oil suction port of the hydraulic pump (3) through the hydraulically controlled one-way valve (2-1); when the pressure of the left high-pressure circuit reaches the set pressure of the overflow valve (5-1), a part of the left high-pressure oil overflows back through the overflow valve (5-1).

9. The fast-closing linear electro-hydraulic actuator with automatic pressure-charging function according to claim 8, characterized in that: The oil circuit control process when the piston rod of the hydraulic cylinder (12) is in the fully extended state is as follows: the explosion-proof motor (4) continues to rotate clockwise, and since the hydraulic cylinder (12) has been fully extended, the high-pressure oil no longer enters the large cylinder chamber of the hydraulic cylinder (12), and directly overflows and returns the oil through the overflow valve 1 (5-1); no return oil is discharged from the small cylinder chamber of the hydraulic cylinder (12), and the right oil port of the hydraulic pump (3) draws oil from the oil tank (1) through the hydraulically controlled one-way valve 1 (2-1).

10. The fast-closing linear electro-hydraulic actuator with automatic pressure-charging function according to claim 9, characterized in that: The oil circuit control process when the actuator loses power suddenly is as follows: the explosion-proof motor (4) is powered off and braked, the hydraulic pump (3) stops and locks, the explosion-proof solenoid valve 1 (9-1) is powered off and is in the conducting position, the high-pressure oil in the accumulator (10) enters the large chamber of the hydraulic cylinder (12) through the explosion-proof solenoid valve 1 (9-1) and the explosion-proof solenoid valve 2 (9-2) and the left one-way valve in the two-way hydraulic lock (11), and at the same time, the high-pressure oil enters the right control chamber of the two-way hydraulic lock (11), opens the right one-way valve of the two-way hydraulic lock (11), the small chamber circuit of the hydraulic cylinder (12) is connected, and the high-pressure oil pushes the piston rod to extend quickly, closing the actuator urgently; the high-pressure oil in the accumulator (10) has already pressed the hydraulic control one-way valve 1 (2-1), and the return oil in the small chamber of the cylinder returns to the oil tank (1) through the hydraulic control one-way valve 1 (2-1).

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