Electro-hydraulic actuation system and method for digital pulse valve

Abstract

The present application provides a digital pulse valve electro-hydraulic execution system, comprising: a storage tank for storing fluid, a bidirectional oil cylinder provided with a detection device for detecting the displacement of the piston, an oil inlet path and an oil outlet path respectively arranged between the bidirectional oil cylinder and the storage tank, the oil inlet path comprising an oil inlet pipe and a check valve connected in series on the oil inlet pipe, an execution unit provided on the oil inlet path for driving the fluid, and the oil outlet path comprising an electromagnetic valve connected in series on the oil outlet path, the technical scheme of the present application has at least the following beneficial effects: there is only one hydraulic element, i.e. a check valve, on the oil inlet path and the oil outlet path, there is no internal leakage point, the oil inlet path and the oil outlet path are independent of each other and do not interfere with each other, the digital quantity turnover pulse trace high-pressure oil of the execution unit is ensured to enter the oil cylinder completely without loss, and high-precision positioning effect is ensured. The self-locking property of the check valve can ensure that the hydraulic oil does not backflow.

Description

Technical Field

[0001] This application relates to the field of electro-hydraulic actuation technology, specifically to an electro-hydraulic actuation system and method for digital pulse valves. Background Technology

[0002] In many industrial sectors, the quality of field control indicators largely depends on the control accuracy of the corresponding valve's drive actuator. The core factor affecting the control accuracy of the actuator is the minimum controllable displacement, making the minimum controllable displacement of the actuator a very critical indicator.

[0003] Existing hydraulic actuators contain components such as directional valves and hydraulic locks. These components have sliding sealing mechanisms, which are prone to internal leakage during use. This affects the minimum displacement of the actuator, making it difficult for traditional hydraulic actuators to achieve a minimum controllable displacement of less than 0.2%. Summary of the Invention

[0004] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide an electro-hydraulic actuation system and method for digital pulse valves, which solves the problem that hydraulic actuators in the prior art are prone to internal leakage, which affects the minimum displacement of the actuator.

[0005] To achieve the above and other related objectives, the present invention provides an electro-hydraulic actuation system for a digital pulse valve, comprising:

[0006] A storage tank for storing fluid;

[0007] A bidirectional hydraulic cylinder is provided with a detection device for detecting piston displacement. The bidirectional hydraulic cylinder includes a rod chamber and a rodless chamber. An oil inlet and an oil outlet are respectively provided between the rod chamber and the storage tank. An oil inlet and an oil outlet are respectively provided between the rodless chamber and the storage tank.

[0008] The oil inlet circuit includes an oil inlet pipe and a one-way valve connected in series on the oil inlet pipe. An actuator for driving the fluid is also provided on the oil inlet circuit.

[0009] The oil outlet path includes a solenoid valve connected in series in the oil outlet path, and an overflow valve for pressure relief is also provided between the storage tank and the bidirectional oil cylinder.

[0010] Optionally, a sequence valve is provided on the oil outlet line, the sequence valve and the solenoid valve are connected in series, and the sequence valve is located close to the bidirectional oil cylinder.

[0011] Optionally, the execution unit employs a dual-channel plunger pump and a drive device, wherein the dual-channel plunger pump includes two inlets and two outlets.

[0012] Optionally, the two inlets of the dual-channel plunger pump are respectively connected to the storage tank, the two outlets of the dual-channel plunger pump are respectively connected to the two check valves, and the two check valves are respectively connected to the rod chamber and the rodless chamber of the storage tank.

[0013] Optionally, a filter is provided between the dual-channel plunger pump and the storage tank.

[0014] Optionally, the drive device includes a servo motor and a handwheel, the servo motor and the handwheel being connected in parallel on the dual-channel plunger pump, and a speed-increasing clutch being provided between the handwheel and the dual-channel plunger pump.

[0015] The present invention also provides an electro-hydraulic actuation method for a digital pulse valve, and an electro-hydraulic actuation system based on any one of the above, characterized in that it includes:

[0016] Start the drive device to drive the dual-channel plunger pump to draw fluid from the storage tank to the oil inlet. Continue to draw fluid, and the fluid enters the bidirectional oil cylinder from the oil inlet, pushing the piston rod to move.

[0017] When the solenoid valve is opened, the piston rod pushes the fluid into the oil outlet and finally back to the storage tank.

[0018] Optionally, a sequence valve is connected in series on the oil outlet line, and the sequence valve is positioned close to the bidirectional cylinder on the oil outlet line. When the drive device is turned on, the solenoid valve opens accordingly, and the fluid in the oil outlet line first rushes through the sequence valve and then returns to the storage tank from the solenoid valve.

[0019] Optionally, the electro-hydraulic actuation method further includes: when the hydraulic pressure in the oil outlet circuit is too high, opening the overflow valve, allowing fluid to return from the overflow valve to the storage tank, thereby reducing the hydraulic pressure in the oil outlet circuit.

[0020] Optionally, the method of driving the dual-channel plunger pump to draw fluid from the storage tank to the inlet circuit includes:

[0021] When the drive unit rotates forward, the dual-channel plunger pump draws fluid from the storage tank to the oil inlet, then into the rodless chamber, and exits from the rod chamber.

[0022] When the drive device reverses, the dual-channel plunger pump draws fluid from the storage tank to the oil inlet, then into the rod chamber, and exits from the rodless chamber.

[0023] As described above, the beneficial effects of the technical solution in this invention include at least the following:

[0024] 1. This application has only one hydraulic component, a check valve, in the oil inlet and outlet circuits. There is no internal leakage point. The oil inlet and outlet circuits are independent of each other and do not interfere with each other. This ensures that the digital pulse micro-high pressure oil of the actuator fully enters the oil cylinder without loss, ensuring high-precision positioning effect.

[0025] 2. The self-locking property of the check valve ensures that the hydraulic oil will not flow back.

[0026] In addition, a sequence valve and a solenoid valve are connected in series in the return oil line to control the hydraulic oil to return to the oil tank, which solves the problems of unidirectional load and pressure shock. The residual air in the oil cylinder is also discharged, and the heat exchange is optimized. Attached Figure Description

[0027] Figure 1 The diagram shown is a structural schematic of an exemplary embodiment of the present invention.

[0028] Part Number Explanation

[0029] 1. Storage tank; 2. Two-way hydraulic cylinder; 3. Oil inlet circuit; 4. Oil outlet circuit; 5. Actuator unit; 6. Check valve; 7. Solenoid valve; 8. First oil inlet pipe; 9. Second oil inlet pipe; 10. First oil outlet pipe; 11. Second oil outlet pipe; 12. Dual-channel plunger pump; 13. Drive unit; 14. Sequence valve; 15. Overflow valve; 16. Servo motor; 17. Speed-increasing clutch; 18. Handwheel. Detailed Implementation

[0030] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0031] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0032] It should be noted that traditional hydraulic actuators, which use servo motors to drive gear pumps, suffer from significant internal leakage, making them highly unsuitable for minimum displacement control. Furthermore, the sliding seals in components such as directional valves and hydraulic locks also contribute to internal leakage, further hindering minimum displacement control. Therefore, achieving a minimum controllable displacement of less than 0.2% is difficult with traditional hydraulic actuators, a challenge that remains prevalent in the traditional hydraulics industry.

[0033] It should be noted that, in this embodiment, it is specified that... Figure 1 The intermediate liquid storage tank is located at the bottom, and the two-way hydraulic cylinder is located at the top.

[0034] Figure 1 A schematic diagram illustrating a structural feature of an exemplary embodiment of this application can be found in [link to relevant documentation]. Figure 1 This invention provides an electro-hydraulic actuation system for a digital pulse valve, comprising: a storage tank 1 and a bidirectional cylinder 2. The storage tank 1 stores hydraulic oil. An inlet passage 3 and an outlet passage 4 are provided between the bidirectional cylinder 2 and the storage tank 1. An actuation unit 5 is provided on the inlet passage 3. The actuation unit 5 is used to draw hydraulic oil from the storage tank 1 into the inlet passage 3 and then deliver it into the bidirectional cylinder 2. The bidirectional cylinder 2 is initially filled with hydraulic oil. After the hydraulic oil from the inlet passage 3 enters the bidirectional cylinder 2, it pushes the piston and piston rod to move. At the same time, the hydraulic oil in another oil chamber of the bidirectional cylinder 2 begins to be delivered to the outlet passage 4. The inlet passage 3 includes an inlet pipe and a one-way valve 6 connected in series on the inlet pipe. Only one one-way valve 6 is provided on the inlet passage 3. The outlet end of the one-way valve 6 is located close to the bidirectional cylinder 2, which can realize the self-flow of the oil circuit. The system features a locking effect and eliminates internal leakage points, ensuring that the digital pulse of high-pressure oil from the oil pump completely enters the cylinder without loss, achieving minimum step control of the cylinder. The oil outlet path 4 includes an oil outlet pipe and a solenoid valve 7 connected in series with the oil outlet pipe. When the execution unit 5 starts working and outputs hydraulic oil to one of the rod chambers (rodless chambers) in the bidirectional cylinder 2, the solenoid valve 7 is opened, and the hydraulic oil in the rodless chamber (rod chamber) of the bidirectional cylinder 2 is delivered to the oil outlet path 4. This is independent of the oil inlet path 3 and does not interfere with it. There is no hydraulic valve on the return path, eliminating leakage points and achieving precise control. Furthermore, the bidirectional cylinder 2 is equipped with a detection device for detecting piston displacement. The detection device feeds back to the CPU to achieve closed-loop control. The detection device can use a displacement sensor or a digital metering method to calculate the valve position.

[0035] Furthermore, there are two oil inlet lines 3 and 4, and the oil outlet line 4 intersects with the oil inlet line 3. The oil inlet line 3 includes a first oil inlet pipe 8 and a second oil inlet pipe 9, and the oil outlet line 4 includes a first oil outlet pipe 10 and a second oil outlet pipe 11. The first oil inlet pipe 8 and the first oil outlet pipe 10 intersect at the upper part, and the second oil inlet pipe 9 and the second oil outlet pipe 11 intersect at the upper part. When oil enters the first oil inlet pipe 8, the solenoid valve 7 on the first oil outlet pipe 10 is closed, and the solenoid valve 7 on the second oil outlet pipe 11 is opened. Oil enters the first oil inlet pipe 8 and is input into the rodless chamber of the bidirectional cylinder 2 through the one-way valve 6. Then, it pushes the piston and piston rod to move into the rod chamber, increasing the volume of the rodless chamber and decreasing the volume of the rod chamber. The hydraulic oil in the rod chamber flows out from the intersection of the second oil inlet pipe 9 and the second oil outlet pipe 11, and then enters the second oil outlet pipe. After passing through the solenoid valve 7, it returns to the storage tank 1.

[0036] Furthermore, the execution unit 5 includes a dual-channel plunger pump 12 and a drive unit 13. The dual-channel plunger pump 12 includes two oil inlets and two oil outlets. Both oil inlets are connected to a storage tank 1, and the two oil outlets are respectively connected to two oil inlet passages 3. Each of the two oil inlet passages 3 is equipped with a one-way valve 6. The drive unit 13 drives the dual-channel plunger pump 12 to draw hydraulic oil from the storage tank 1, and then the oil enters the oil inlet passage 3 through the oil outlet. In this embodiment, when the drive unit 13 rotates forward, oil enters the rodless chamber and exits the rod chamber; when the drive unit 13 rotates in reverse, oil enters the rod chamber and exits the rodless chamber. The dual-channel plunger electro-hydraulic actuator utilizes the forward and reverse rotation of a bidirectional pump to generate two streams of pressurized oil, which are output independently through two channels to control the reciprocating motion of the bidirectional cylinder 2. It eliminates the need for a reversing valve, making the system simple and reliable. The bidirectional pump has high volumetric efficiency and eliminates the "oil trapping" phenomenon, allowing for pumping at lower speeds and achieving high-precision positioning control. The dual-channel plunger pump 12 employs a mechanical seal plunger pump structure, ensuring pressurized pumping at a minimum speed of 1 RPM. The oil output is proportional to the motor speed, with a lower speed limit below 1 RPM. Following the rotational pulse control, it can achieve controllable displacement below 0.2%.

[0037] Furthermore, a sequence valve 14 is connected in series on the oil outlet 4, and the sequence valve 14 is set close to the bidirectional cylinder 2. The solenoid valve 7 is set close to the storage tank 1. The sequence valve 14 is set to form back pressure to balance the load in the same direction and solve the problem of hydraulic oil impact when the solenoid valve 7 opens. When the drive device 13 drives the dual-channel plunger pump to draw hydraulic oil from the storage tank to the oil inlet, it enters one end of the bidirectional cylinder and the other end of the bidirectional cylinder starts to output oil. At the same time, the solenoid valve will open, and the hydraulic oil from the other end of the bidirectional cylinder will be squeezed. When the pressure of the sequence valve detection circuit is too high, the sequence valve opens, the hydraulic oil flows through the sequence valve, enters the solenoid valve, and finally returns to the storage tank. This can avoid the hydraulic oil returning directly to the storage tank at the moment the solenoid valve opens.

[0038] Furthermore, an overflow valve 15 is also provided on the oil outlet 4. The oil inlet end of the overflow valve 15 is connected in parallel to the oil outlet 4, and the oil outlet section of the overflow valve 15 is connected to the storage tank 1 to control the upper limit of pressure and realize pressure protection. When the pressure is too high, the overflow valve 15 is opened, and part of the hydraulic oil returns from the overflow valve to the storage tank to realize pressure protection.

[0039] Furthermore, the drive unit 13 includes a servo motor 16 and a handwheel 18, which are connected in parallel to the dual-channel plunger pump 12. Both the servo motor 16 and the handwheel 18 can drive the dual-channel plunger pump 12 to work. A speed-increasing clutch 17 is also provided between the handwheel 18 and the dual-channel plunger pump 12 to ensure that the handwheel 18 can drive the dual-channel plunger pump 12 to run. The servo motor 16 is set as the power element to drive the oil pump. The speed control and positioning control are combined. The speed control is used to adapt to different speed requirements and achieve a minimum speed control of 1 RPM. The positioning control is used to meet the requirements of digital pulse drive, where each pulse corresponds to a full revolution, realizing rotational pulse control.

[0040] This application also provides an electro-hydraulic actuation method for a digital pulse valve, based on the above-mentioned electro-hydraulic actuation system, comprising:

[0041] Start the servo motor 16 or turn the handwheel 18 to rotate forward (reverse), and at the same time open the solenoid valve 7 to drive the dual-channel plunger pump 12 to draw hydraulic oil from the storage tank 1 to the oil inlet 3. The hydraulic oil enters the rodless chamber (rod chamber) of the bidirectional cylinder 2 from the oil inlet 3 and pushes the piston rod to move towards the rod chamber (rodless chamber). The piston pushes the hydraulic oil into the oil outlet 4, passes through the solenoid valve 7, and returns to the storage tank 1.

[0042] Furthermore, a sequence valve 14 is connected in series on the oil outlet 4, and the sequence valve 14 is positioned close to the bidirectional cylinder 2 on the oil outlet 4. When the drive device 13 is opened, the solenoid valve 7 opens accordingly, the fluid in the oil outlet 4 is squeezed, the pressure is detected, the sequence valve 14 is opened, and then the fluid returns to the storage tank from the solenoid valve 7.

[0043] Furthermore, when the hydraulic pressure in the oil outlet 4 is too high, the overflow valve 15 is opened, and the fluid returns from the overflow valve 15 to the storage tank 1, reducing the hydraulic pressure in the oil outlet 4.

[0044] Furthermore, driving the dual-channel plunger pump 12 to draw fluid from the storage tank 1 to the oil inlet 3 includes:

[0045] When the drive unit 13 rotates forward, the dual-channel plunger pump 12 draws fluid from the storage tank 1 to the oil inlet 3, then into the rodless chamber, and out of the rod chamber;

[0046] When the drive unit 13 reverses, the dual-channel plunger pump 12 draws fluid from the storage tank 1 to the oil inlet 3, then into the rod chamber, and out of the rodless chamber.

[0047] Working principle: Hydraulic oil is provided in both the rod chamber and the rodless chamber of the bidirectional hydraulic cylinder 2. When the servo motor 16 is started or the handwheel 18 is turned to rotate forward, the solenoid valve 7 is opened at the same time, driving the dual-channel plunger pump 12 to draw hydraulic oil from the storage tank 1 to the first oil inlet pipe 8. Then, it passes through the check valve 6. After passing through the check valve 6, the check valve 6 has a self-locking function to prevent the hydraulic oil from flowing back. Then, it is delivered from the outlet end of the check valve 6 to the rodless chamber of the bidirectional hydraulic cylinder 2. The increase of hydraulic oil in the rodless chamber squeezes the rod chamber, pushing the piston and piston rod into the rod chamber, reducing the volume of the rod chamber. The hydraulic oil in the rod chamber flows out from the second oil outlet pipe 11, passes through the sequence valve 14 and the solenoid valve 7, and returns to the storage tank 1.

[0048] Start the servo motor 16 or turn the handwheel 18 in reverse, and at the same time open the solenoid valve 7 to drive the dual-channel plunger pump 12 to draw hydraulic oil from the storage tank 1 to the second oil inlet line 9. Then, through the check valve 6, the hydraulic oil is delivered from the outlet end of the check valve 6 to the rod chamber of the double-acting cylinder 2. The hydraulic oil in the rodless chamber flows out from the first oil outlet line 10, passes through the sequence valve 14 and the solenoid valve 7, and returns to the storage tank 1.

[0049] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. An electro-hydraulic actuation system for a digital pulse valve, characterized in that, include: A storage tank for storing fluid; A bidirectional hydraulic cylinder is provided with a detection device for detecting piston displacement. The bidirectional hydraulic cylinder includes a rod chamber and a rodless chamber. An oil inlet and an oil outlet are respectively provided between the rod chamber and the storage tank. An oil inlet and an oil outlet are respectively provided between the rodless chamber and the storage tank. The oil inlet circuit includes an oil inlet pipe and a one-way valve connected in series on the oil inlet pipe. An actuator for driving the fluid is also provided on the oil inlet circuit. The oil outlet path includes a solenoid valve connected in series in the oil outlet path, and an overflow valve for pressure relief is also provided between the storage tank and the bidirectional oil cylinder. A sequence valve is provided on the oil outlet line. The sequence valve and the solenoid valve are connected in series, and the sequence valve is located close to the bidirectional oil cylinder.

2. The electro-hydraulic actuation system for a digital pulse valve according to claim 1, characterized in that: The execution unit employs a dual-channel plunger pump and a drive device. The dual-channel plunger pump includes two inlets and two outlets.

3. The electro-hydraulic actuation system for a digital pulse valve according to claim 2, characterized in that: The two inlets of the dual-channel plunger pump are respectively connected to the storage tank, and the two outlets of the dual-channel plunger pump are respectively connected to the two check valves. The two check valves are respectively connected to the rod chamber and the rodless chamber of the bidirectional cylinder.

4. The electro-hydraulic actuation system for a digital pulse valve according to claim 3, characterized in that: A filter is provided between the dual-channel plunger pump and the storage tank.

5. The electro-hydraulic actuation system for a digital pulse valve according to claim 2, characterized in that: The drive device includes a servo motor and a handwheel, the servo motor and the handwheel are connected in parallel to the dual-channel plunger pump, and a speed-increasing clutch is provided between the handwheel and the dual-channel plunger pump.

6. An electro-hydraulic actuation method for a digital pulse valve, based on the electro-hydraulic actuation system of the digital pulse valve according to any one of claims 2-5, characterized in that, include: Start the drive unit to drive the dual-channel plunger pump to draw fluid from the storage tank to the oil inlet. Continue to draw fluid, and the fluid enters the double-acting oil cylinder from the oil inlet, pushing the piston rod to move. When the solenoid valve is opened, the piston rod pushes the fluid into the oil outlet and finally back to the storage tank.

7. The electro-hydraulic actuation method for a digital pulse valve according to claim 6, characterized in that: A sequence valve is connected in series on the oil outlet line and positioned close to the bidirectional cylinder on the oil outlet line. When the drive device is turned on, the solenoid valve opens accordingly, the fluid in the oil outlet line is squeezed, the pressure is detected, the sequence valve is opened, and then the fluid returns to the storage tank from the solenoid valve.

8. The electro-hydraulic actuation method for a digital pulse valve according to claim 6, characterized in that, The electro-hydraulic actuation method further includes: when the hydraulic pressure in the oil outlet circuit is too high, opening the overflow valve, allowing fluid to return from the overflow valve to the storage tank, thereby reducing the hydraulic pressure in the oil outlet circuit.

9. The electro-hydraulic actuation method for a digital pulse valve according to claim 6, characterized in that, The dual-channel plunger pump draws fluid from the storage tank to the inlet circuit, including: When the drive unit rotates forward, the dual-channel plunger pump draws fluid from the storage tank to the oil inlet, then into the rodless chamber, and exits from the rod chamber. When the drive device reverses, the dual-channel plunger pump draws fluid from the storage tank to the oil inlet, then into the rod chamber, and exits from the rodless chamber.

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