Speed regulating electro-hydraulic control system and application thereof

Abstract

The application relates to the technical field of hydraulic control, in particular to a speed-regulating electro-hydraulic control system and application, wherein the speed-regulating electro-hydraulic control system comprises a first reversing valve, a second reversing valve and a control system, the first reversing valve is provided with a first liquid inlet and a first liquid return port, the first reversing valve is switchable between a first state, a second state and a third state, the second reversing valve is provided with a second liquid inlet and a second liquid return port, the second reversing valve is switchable between a fourth state and a fifth state, the control system comprises a third reversing valve, the third reversing valve is connected with the second reversing valve to control the second reversing valve to switch between the fourth state and the fifth state, and the control system is also used for controlling the first reversing valve to switch between the first state, the second state and the third state; the speed-regulating electro-hydraulic control system can reduce the reform cost and improve the control precision.

Description

Technical Field

[0001] This invention relates to the field of hydraulic control technology, specifically to a speed-regulating electro-hydraulic control system and its application. Background Technology

[0002] The electro-hydraulic directional valve is a core component of an electro-hydraulic control system. It is a hydraulically actuated directional valve composed of a solenoid pilot valve and a main valve. High-pressure fluid in the solenoid pilot valve's hydraulic circuit drives the main valve spool, controlling the movement of the actuator. As a key component in the electro-hydraulic control of hydraulic supports, the electro-hydraulic directional valve plays a crucial role in realizing fully mechanized and unmanned mining in coal mines. Related technologies often employ electro-hydraulic servo valves with valve-controlled cylinders or use multiple directional valves with different flow rates working in tandem to achieve flow control and improve accuracy. However, this requires reconnecting pipelines, resulting in high modification costs. Summary of the Invention

[0003] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, embodiments of this invention propose a speed-regulating electro-hydraulic control system that can reduce modification costs while improving control accuracy.

[0004] This invention also proposes an application of a speed-regulating electro-hydraulic control system.

[0005] The speed-regulating electro-hydraulic control system of this invention includes: a first directional valve having a first inlet and a first return port, switchable between a first state, a second state, and a third state; in the first state, the first return port is adapted to communicate with a first chamber of an actuator; in the second state, a portion of the first inlet is communicated with the first chamber; and in the third state, the entire first inlet is communicated with the first chamber; a second directional valve having a second inlet and a second return port, switchable between a fourth state and a fifth state; in the fourth state, the second inlet is communicated with a second chamber of the actuator; and in the fifth state, the second return port is communicated with the second chamber; and a control system including a third directional valve connected to the second directional valve to control the switching of the second directional valve between the fourth and fifth states, and the control system further being used to control the switching of the first directional valve between the first, second, and third states.

[0006] The speed-regulating electro-hydraulic control system of this invention can reduce modification costs while improving control accuracy.

[0007] In some embodiments, the second directional valve has a second control port and a second working port, and the third directional valve has a third inlet port, a third return port and a third working port. The second working port is connected to the second chamber, and the third working port is connected to the second control port. When the third working port is connected to the third inlet port, the second directional valve is in a fourth state. When the third working port is connected to the third return port, the second directional valve is in a fifth state.

[0008] In some embodiments, the speed-regulating electro-hydraulic control system further includes an inlet pipe and a return pipe, wherein the second inlet is connected to the inlet pipe and the second return pipe is connected to the return pipe; in the fourth state, the second working port is connected to the second inlet; and in the fifth state, the second working port is connected to the second return port.

[0009] In some embodiments, the first reversing valve has a first working port, which is connected to the first chamber, a first inlet port is connected to the inlet pipeline, and a first return port is connected to the return pipeline. In the first state, the first working port is connected to the first return port. In the second state, the first working port is connected to a portion of the first inlet port. In the third state, the first working port is connected to the entire first inlet port.

[0010] In some embodiments, the control system further includes a first pilot valve having a fourth inlet, a fourth return port, and a fourth working port; a first directional valve having a first control port; a third directional valve having a third control port; the fourth inlet being connected to the inlet pipeline; the fourth return port being connected to the return pipeline; and the fourth working port being connected to both the first control port and the third control port so that the first directional valve is in a second or third state while simultaneously enabling the third working port of the third directional valve to be connected to the third return port, and the third return port to be connected to the return pipeline.

[0011] In some embodiments, the control system further includes a second pilot valve having a fifth inlet, a fifth return port, and a fifth working port. The fifth inlet is connected to the inlet pipeline, the fifth return port is connected to the return pipeline, and the fifth working port is connected to the third inlet.

[0012] In some embodiments, the control system further includes a one-way relief valve having a first inlet and a first outlet, the first inlet being connected to the fourth working port, the first control port and the third control port, and the first outlet being connected to the fifth working port and the third liquid inlet.

[0013] In some embodiments, the control system further includes a controller that can be connected to the first pilot valve to connect the fourth working port to the fourth inlet port, and when the controller is disconnected from the first pilot valve, the fourth working port is connected to the fourth return port; and / or, the controller can be connected to the second pilot valve to connect the fifth working port to the fifth inlet port, and when the controller is disconnected from the second pilot valve, the fifth working port is connected to the fifth return port.

[0014] In some embodiments, the control system further includes: a first check valve disposed on the inlet line; and / or a second check valve disposed on the return line; and / or a filter disposed on the inlet line.

[0015] The application of the speed-regulating electro-hydraulic control system in this embodiment of the invention, wherein the speed-regulating electro-hydraulic control system is used to control a hydraulic cylinder or a hydraulic motor.

[0016] The speed-regulating electro-hydraulic control system of this invention is used to control hydraulic cylinders and hydraulic motors, and can improve the control accuracy of the speed-regulating electro-hydraulic control system on hydraulic cylinders or hydraulic motors. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the speed-regulating electro-hydraulic control system controlling the hydraulic cylinder according to an embodiment of the present invention.

[0018] Figure 2 This is a schematic diagram of the speed-regulating electro-hydraulic control system controlling the hydraulic motor according to an embodiment of the present invention.

[0019] Figure label:

[0020] Actuator 100, hydraulic cylinder 110, first chamber 111, second chamber 112, piston 113, piston rod 114, hydraulic motor 120.

[0021] First directional valve 1, first inlet 11, first return port 12, first control port 13, first working port 14; second directional valve 2, second inlet 21, second return port 22, second control port 23, second working port 24.

[0022] Control system 3, third directional valve 31, third inlet 311, third return port 312, third control port 313, third working port 314, first pilot valve 32, fourth inlet 321, fourth return port 322, fourth working port 323, second pilot valve 33, fifth inlet 331, fifth return port 332, fifth working port 333, one-way relief valve 34, first inlet 341, first outlet 342, controller 35, first check valve 36, second check valve 37, filter 38.

[0023] Inlet pipe 4, return pipe 5. Detailed Implementation

[0024] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0025] like Figure 1 As shown, the speed-regulating electro-hydraulic control system of this embodiment includes a first reversing valve, a second reversing valve, and a control system.

[0026] The first directional valve 1 has a first inlet port 11 and a first return port 12. The first directional valve 1 is switchable between a first state, a second state, and a third state. In the first state, the first return port 12 is adapted to communicate with the first chamber 111 of the actuator 100. In the second state, a portion of the first inlet port 11 communicates with the first chamber 111. In the third state, the entire first inlet port 11 communicates with the first chamber 111. The second directional valve 2 has a second inlet port 21 and a second return port 22. The second directional valve 2 is switchable between a fourth state and a fifth state. In the fourth state, the second inlet port 21 communicates with the second chamber 112 of the actuator 100. In the fifth state, the second return port 22 communicates with the second chamber 112. The control system 3 includes a third directional valve 31, which is connected to the second directional valve 2 to control the switching of the second directional valve 2 between the fourth and fifth states. The control system 3 is also used to control the switching of the first directional valve 1 between the first, second, and third states.

[0027] The first directional valve 1 is connected to the first chamber 111. In the first state, the first inlet 11 of the first directional valve 1 is disconnected from the first chamber 111, and the first return port 12 is connected to the first chamber 111. In the second state, the first inlet 11 of the first directional valve 1 is partially connected to the first chamber 111, and the first return port 12 is disconnected from the first chamber 111. In the third state, the first inlet 11 of the first directional valve 1 is fully connected to the first chamber 111, and the first return port 12 is disconnected from the first chamber 111. The second directional valve 2 is connected to the second chamber 112. In the fourth state, the second inlet 21 of the second directional valve 2 is connected to the second chamber 112, and the second return port 22 is disconnected from the second chamber 112. In the fifth state, the second inlet 21 of the second directional valve 2 is disconnected from the second chamber 112, and the second return port 22 is connected to the second chamber 112. The third directional valve 31 is connected to the second directional valve 2. By adjusting the working state of the third directional valve 31, the state of the second directional valve 2 can be adjusted, so that the second directional valve 2 is in the fourth state or in the fifth state.

[0028] In the first state, the first directional valve 1 is in a non-operating state, meaning its return flow is activated and it is in a return flow state. The first return port 12 is connected to the first chamber 111, and the first working fluid in the first chamber 111 flows out through the first directional valve 1 from the first return port 12. In the second state, the first directional valve 1 is in an operating state. At this time, the first inlet port 11 is partially opened, putting the first directional valve 1 in a fluid inlet state. A portion of the first inlet port 11 is connected to the first chamber 111, meaning the area of ​​the first inlet port 11 that is open is smaller than the area of ​​the first inlet port 11. The first working fluid can enter the first chamber 111 at a small flow rate through the first inlet port 11. The first working fluid is the working fluid that enters and exits the first chamber 111. When the first reversing valve 1 is in the third state, the first reversing valve 1 is in the working state, and the first inlet 11 is fully opened and connected to the first chamber 111. That is, the area of ​​the first inlet 11 is equal to the area of ​​the first inlet 11, and the first working fluid can enter the first chamber 111 in a large flow rate through the first inlet 11.

[0029] For example, the inlet area of ​​the first inlet 11 is S. When the first directional valve 1 is in the first state, the flow area of ​​the first inlet 11 is 0. When the first directional valve 1 is in the second state, the flow area of ​​the first inlet 11 is smaller than the area of ​​the first inlet 11. The flow area of ​​the first inlet 11 is greater than zero and smaller than the inlet area, and can be 0.1S, 0.2S, 0.5S, 0.7S, 0.85S, etc. When the first directional valve 1 is in the third state, the flow area of ​​the first inlet 11 is equal to the area of ​​the first inlet 11, that is, the flow area of ​​the first inlet 11 is S. That is, the first directional valve 1 switches between zero flow, small flow, and full flow. That is, the first directional valve 1 is a three-position three-way directional valve. The embodiments of the present invention do not limit the specific structure of the first directional valve 1. As long as the first directional valve 1 can switch between zero flow, a set small flow, and full flow, it falls within the protection scope of the present invention.

[0030] In the fourth state, the second inlet 21 of the second directional valve 2 is connected to the second chamber 112. At this time, the second directional valve 2 is in the inlet state, and the second working fluid can enter the second chamber 112 through the second inlet 21. In the fifth state, the second return port 22 is connected to the second chamber 112, and the second inlet 21 is disconnected from the second chamber 112. At this time, the second directional valve 2 is in the return state, and the second working fluid in the second chamber 112 can flow out through the second return port 22. The second working fluid is the fluid that enters and exits the second chamber 112.

[0031] The first inlet 11 and the second inlet 21 can use the same working fluid at the same pressure, that is, the pressure of the first working fluid and the second working fluid are the same, for example, the first working fluid and the second working fluid are the same working fluid. By controlling the first reversing valve 1 through the control system 3 and controlling the second reversing valve 2 through the third reversing valve 31 to be in different states, the speed regulating electro-hydraulic control system can have the following three different working states. The actuator 100 is explained below using the hydraulic cylinder 110 as an example.

[0032] It is understood that the hydraulic cylinder 110 includes a cylinder barrel, a piston 113, and a piston rod 114. The piston 113 divides the cylinder barrel into a first chamber 111 and a second chamber 112. The piston rod 114 is located in the second chamber 112 and is connected to the piston 113. The first chamber 111 is a rodless chamber, and the second chamber 112 is a rod-type chamber.

[0033] In the first working state of the speed-regulating electro-hydraulic control system, the control system 3 controls the first reversing valve 1 to be in the first state, and the third reversing valve 31 controls the second reversing valve 2 to be in the fourth state. At this time, the first reversing valve 1 is in the return state, and the first working fluid in the first chamber 111 flows out through the first return port 12. The second reversing valve 2 is in the inlet state, and the second working fluid can enter the second chamber 112 through the second inlet port 21, so that the working pressure in the second chamber 112 is greater than the working pressure in the first chamber 111. As a result, the second working fluid in the second chamber 112 applies a thrust to the piston 113 toward the first chamber 111. Under the action of this thrust, the piston 113 moves toward the first chamber 111, and the piston rod 114 retracts.

[0034] In the second working state of the speed-regulating electro-hydraulic control system, the control system 3 controls the first reversing valve 1 to be in the second state, and the third reversing valve 31 controls the second reversing valve 2 to be in the fifth state. At this time, the first reversing valve 1 is in the low-flow-rate liquid inlet state, and the first working fluid enters the first chamber 111 at a low flow rate through the first inlet 11. The second reversing valve 2 is in the return state, and the second working fluid flows out of the second chamber 112 through the second return port 22. This causes the working fluid in the first chamber 111 to exert a thrust on the piston 113 toward the second chamber 112. Under the action of this thrust, the piston 113 moves slowly toward the second chamber 112, and the piston rod 114 slowly extends outward.

[0035] In the third working state of the speed-regulating electro-hydraulic control system, the control system 3 controls the first reversing valve 1 to be in the third state, and the third reversing valve 31 controls the second reversing valve 2 to be in the fifth state. At this time, the first reversing valve 1 is in the full-flow liquid inlet state, and the first working fluid enters the first chamber 111 at a large flow rate through the first inlet 11. The second reversing valve 2 is in the return state, and the second working fluid flows out of the second chamber 112 through the second return port 22. This causes the working fluid in the first chamber 111 to exert a thrust on the piston 113 toward the second chamber 112. Under the action of this thrust, the piston 113 moves rapidly toward the second chamber 112. In the third working state, the piston 113 extends outward rapidly, and the thrust on the piston 113 in the third working state is greater than the thrust on the piston 113 in the second working state.

[0036] The speed-regulating electro-hydraulic control system of this embodiment switches between full-flow inlet, small-flow inlet, and return states through the control system 3, and the third directional valve 31 controls the second directional valve 2 to switch between the fourth and fifth states, so that the speed-regulating electro-hydraulic control system can realize the above three working states, namely, the first working state is the retraction of the hydraulic cylinder 110, the second working state is the slow extension of the hydraulic cylinder 110 with a small flow, and the third working state is the rapid extension of the hydraulic cylinder 110 with a full flow, which improves the control accuracy of the speed-regulating electro-hydraulic control system.

[0037] This embodiment of the invention adjusts the working state of the second directional valve 2 through the third directional valve 31. Compared with the related technology of adding a valve to the speed-regulating electro-hydraulic control system, this embodiment of the invention does not require reconnecting pipelines, requires less modification, and has lower modification costs. In specific implementation, by reasonably designing the flow rate of the first directional valve 1 in the second state, the extension speed of the hydraulic cylinder 110 in the second working state can be adjusted, thereby achieving the control accuracy of the position of the actuator 100 and improving the control accuracy of the speed-regulating electro-hydraulic control system on the actuator 100.

[0038] In some embodiments, the second directional valve 2 has a second control port 23 and a second working port 24, and the third directional valve 31 has a third inlet port 311, a third return port 312 and a third working port 314. The second working port 24 is connected to the second chamber 112, and the third working port 314 is connected to the second control port 23. When the third working port 314 is connected to the third inlet port 311, the second directional valve 2 is in a fourth state. When the third working port 314 is connected to the third return port 312, the second directional valve 2 is in a fifth state.

[0039] Specifically, when the third working port 314 is connected to the third liquid inlet 311, the third directional valve 31 is in the liquid inlet state to control the second directional valve 2 to be in the fourth state. When the third working port 314 is connected to the third liquid return port 312, the third directional valve 31 is in the liquid return state to control the second directional valve 2 to be in the fifth state.

[0040] When the third directional valve 31 is in the liquid inlet state, the working fluid in the third directional valve 31 enters the second control port 23 through the third liquid inlet 311 and the third working port 314, controlling the second directional valve 2 to be in the fourth state. The second working fluid flows into the second chamber 112 through the second liquid inlet 21 and the second working port 24. Since the first directional valve 1 is in the first state at this time, that is, the first directional valve 1 is in the liquid return state, the second working fluid in the second chamber 112 applies a thrust to the piston 113 toward the first chamber 111. Under the action of this thrust, the piston 113 moves toward the first chamber 111, and the piston rod 114 retracts.

[0041] When the third reversing valve 31 is in the return state, the third working port 314 is connected to the third return port 312, and the third working port 314 no longer supplies control fluid to the second control port 23. The second reversing valve 2 is in the fifth state, and the second working fluid in the second chamber 112 can flow out through the second working port 24 and the second return port 22. At this time, the first reversing valve 1 is in the second state or the third state. If the first reversing valve 1 is in the second state, the first inlet port 11 is partially connected to the first chamber 111 to realize a small flow of fluid into the first chamber 111, so that the working fluid in the first chamber 111 applies a thrust to the piston 113 toward the second chamber 112. Under the action of this thrust, the piston 113 moves slowly toward the second chamber 112, and the piston rod 114 slowly extends outward. If the first reversing valve 1 is in the third state at this time, the first reversing valve 1 is in the full-flow liquid inlet state. The first working fluid enters the first chamber 111 at a large flow rate through the first inlet 11 and the first working port 14. Under the action of the thrust, the piston 113 moves rapidly toward the second chamber 112, and the piston rod 114 extends outward rapidly at full flow rate.

[0042] In this embodiment of the invention, the initial states of the first directional valve 1 and the second directional valve 2 of the speed-regulating electro-hydraulic control system are both in the return state, and the initial state of the third directional valve 31 is in the inlet state. By adjusting the state of the third directional valve 31, the state of the second directional valve 2 is adjusted. When the hydraulic cylinder 110 needs to extend quickly, a large flow rate is used, and when precise position control is required, a small flow rate is used. By adjusting the flow rate of the first directional valve 1 and the working state of the second directional valve 2, the control accuracy of the electro-hydraulic control system on the hydraulic cylinder 110 is improved.

[0043] In some embodiments, the speed-regulating electro-hydraulic control system further includes an inlet pipe 4 and a return pipe 5. The second inlet port 21 is connected to the inlet pipe 4, and the second return port 22 is connected to the return pipe 5. In the fourth state, the second working port 24 is connected to the second inlet port 21, and in the fifth state, the second working port 24 is connected to the second return port 22.

[0044] Specifically, the second control port 23 is controlled by the third reversing valve 31 to switch the second reversing valve 2 between the fourth and fifth states. When the second reversing valve 2 is in the fourth state, the second working port 24 is connected to the second inlet port 21. At this time, the second working fluid can flow into the second chamber 112 through the second inlet port 21 and the second working port 24. When the second reversing valve 2 is in the fifth state, the second working port 24 is connected to the second return port 22. At this time, the second working fluid in the second chamber 112 can flow out through the second working port 24 and the second return port 22.

[0045] The second inlet 21 is directly connected to the inlet pipe 4, and the second return port 22 is directly connected to the return pipe 5, which facilitates the connection and disconnection of the second reversing valve 2 with the inlet pipe 4 and the return pipe 5.

[0046] In some embodiments, the first reversing valve 1 has a first working port 14, which is connected to the first chamber 111, the first inlet port 11 is connected to the inlet pipe 4, and the first return port 12 is connected to the return pipe 5. In a first state, the first working port 14 is connected to the first return port 12. In a second state, the first working port 14 is connected to a portion of the first inlet port 11. In a third state, the first working port 14 is fully connected to the first inlet port 11.

[0047] Specifically, the connection between the first working port 14 and the first return port 12 can be understood as follows: when the first return port 12 is open, the first chamber 111 is connected to the first working port 14 and the first return port 12, and the first working fluid in the first chamber 111 flows out through the first return port 12. The partial connection between the first working port 14 and the first inlet port 11 can be understood as follows: the open area of ​​the first inlet port 11 is smaller than the area of ​​the first inlet port 11 itself. In this case, the first working fluid can enter the first working port 14 at a small flow rate. The complete connection between the first working port 14 and the first inlet port 11 can be understood as follows: the open area of ​​the first inlet port 11 is equal to the area of ​​the first inlet port 11 itself. In this case, the first working fluid can enter the first working port 14 at a large flow rate.

[0048] The first inlet 11 is directly connected to the inlet pipe 4, and the first return port 12 is directly connected to the return pipe 5, which facilitates the connection and disconnection of the first reversing valve 1 with the inlet pipe 4 and the return pipe 5.

[0049] In some embodiments, the control system 3 further includes a first pilot valve 32, which has a fourth inlet 321, a fourth return port 322, and a fourth working port 323. The first directional valve 1 has a first control port 13, and the third directional valve 31 has a third control port 313. The fourth inlet 321 is connected to the inlet pipeline 4, the fourth return port 322 is connected to the return pipeline 5, and the fourth working port 323 is connected to the first control port 13 and the third control port 313 respectively, so that the first directional valve 1 is in the second state or the third state, while the third working port 314 of the third directional valve 31 is connected to the third return port 312, and the third return port 312 is connected to the return pipeline 5.

[0050] Specifically, when the first pilot valve 32 is opened, the fourth inlet port 321 is connected to the inlet pipeline 4, and the first pilot valve 32 is in the inlet state. The pilot fluid can enter the first pilot valve 32 through the fourth inlet port 321 and flow into the first control port 13 of the first directional valve 1 and the third control port 313 of the third directional valve 31 through the fourth working port 323. That is, the fourth working port 323 of the first pilot valve 32 is split into two paths. The first path flows to the first control port 13 to control the first directional valve 1 to switch between the second and third states. The second path flows to the third control port 313 to control the third working port 314 of the third directional valve 31 to connect with the third return port 312, so that the third directional valve 31 is in the return state. The third working port 314 no longer supplies control fluid to the second control port, thereby switching the second directional valve 2 to the fifth state.

[0051] When the first pilot valve 32 is closed, it is in the return state. The fourth working port 323 is disconnected from the fourth inlet port 321 and connected to the fourth return port 322. The control fluid in the first control port 13 flows into the first pilot valve 32 through the fourth working port 323 and flows out through the fourth return port 322, so that the first directional valve 1 is in the first state. At the same time, the control fluid in the third control port 313 flows into the first pilot valve 32 through the fourth working port 323 and flows out through the fourth return port 322, so that the third directional valve 31 is in the inlet state.

[0052] The speed-regulating electro-hydraulic control system of this embodiment controls the first directional valve 1 in the first, second, and third states by setting the first pilot valve 32, and simultaneously controls the inlet and return states of the third directional valve 31 by the first pilot valve 32, thereby controlling the second directional valve 2 in the fifth and sixth states. This makes the speed-regulating electro-hydraulic control system of this embodiment simple in structure and easier to adjust.

[0053] For example, the first pilot valve 32 is an electromagnetic pilot valve.

[0054] In some embodiments, the control system 3 further includes a second pilot valve 33, which has a fifth inlet 331, a fifth return port 332 and a fifth working port 333. The fifth inlet 331 is connected to the inlet pipeline 4, the fifth return port 332 is connected to the return pipeline 5, and the fifth working port 333 is connected to the third inlet 311.

[0055] When the second pilot valve 33 is opened, the fifth working port 333 is connected to the fifth inlet port 331, which is connected to the inlet pipeline 4. The pilot fluid enters the second pilot valve 33 through the fifth inlet port 331 and flows out through the fifth working port 333. When the first pilot valve 32 is closed, causing the third directional valve 31 to be in the inlet state, the pilot fluid flowing out of the fifth working port 333 is transmitted to the third directional valve through the third inlet port and then to the second control port through the third working port to control the second directional valve to be in the fourth state. When the second directional valve is in the fourth state, the second inlet port 21 is connected to the inlet pipeline 4, and the second working fluid flows into the second chamber 112 through the second inlet port 21 and the second working port 24.

[0056] When the second pilot valve 33 is closed, the fifth inlet port 331 is disconnected from the fifth working port 333, and the fifth return port 332 is connected to the fifth working port 333. The second pilot valve 33 is in the return state, and the fifth return port 332 is connected to the return pipeline 5. At this time, the working fluid in the third directional valve 31 flows out through the third return port 312, which is connected to the return pipeline 5. The control fluid in the second control port 23 of the second directional valve 2 flows out through the third working port 314 and the third return port 312 of the third directional valve 31, so that the third directional valve 31 is in the return state, and the second directional valve 2 is in the fifth state.

[0057] Therefore, by setting the second pilot valve 33 and the third reversing valve 31 to control the second reversing valve 2 to switch between the fourth and fifth states, the speed regulation electro-hydraulic control system of this embodiment of the invention can be adjusted and controlled more accurately and conveniently.

[0058] For example, the second pilot valve 33 is an electromagnetic pilot valve.

[0059] In some embodiments, the control system 3 further includes a one-way relief valve 34, which has a first inlet 341 and a first outlet 342. The first inlet 341 is connected to a fourth working port 323, a first control port 13 and a third control port 313, and the first outlet 342 is connected to a fifth working port 333 and a third liquid inlet 311.

[0060] Specifically, the pilot fluid flowing out of the fourth working port 323 of the first pilot valve 32 is divided into three paths. The first path flows to the first control port 13 to control the first directional valve 1 to switch between the second and third states. The second path flows to the third control port 313 to control the third directional valve 31 to be in the return state. The third path flows to the first inlet 341 of the one-way overflow valve 34 to regulate the pressure flowing to the first control port 13 of the first directional valve 1.

[0061] The pilot fluid flowing out of the fifth working port 333 of the second pilot valve 33 is divided into two paths. The fourth path flows to the first outlet 342, and the fifth path flows to the third inlet 311 of the third directional valve 31 and enters the third directional valve 31. The control fluid is delivered to the second control port 23 through the third working port 314 of the third directional valve 31. The pressure flowing to the first control port 13 is controlled by setting a one-way overflow valve 34 to regulate the flow rate through the first directional valve 1, thereby improving the control accuracy of the speed regulation electro-hydraulic control system.

[0062] When the speed-regulating electro-hydraulic control system of this embodiment of the invention needs to be in the first working state, the second pilot valve 33 is opened while the first pilot valve 32 is closed. The first pilot valve 32 is closed, the fourth working port 323 is connected to the fourth return port 322, and the fourth return port 322 is connected to the return pipeline 5. The control fluid of the first control port 13 and the control fluid of the third control port 313 flow back to the return pipeline 5 through the fourth working port 323 and the fourth return port 322. The first reversing valve 1 is in the first state, and the third reversing valve 31 is in the liquid inlet state. The second pilot valve 33 is opened, and the pilot fluid enters the second pilot valve 33 through the fifth inlet port 331 and flows out through the fifth working port 333. The pressure of the pilot fluid is set to P0. Since the pilot fluid flowing out of the fifth working port 333 cannot flow from the first outlet 342 of the one-way relief valve 34 to the first inlet 341 of the one-way relief valve 34, the one-way relief valve 34 does not work and will not affect the pressure of the pilot fluid. This keeps the pressure of the pilot fluid flowing from the fifth working port 333 to the third inlet port 311 at P0 and flows into the second control port 23 through the third working port 314. This makes the second directional valve 2 open at full flow, so that the second inlet port 21 of the second directional valve 2 is connected to the inlet pipeline 4. The second directional valve 2 is in the fourth state, and the piston rod 114 of the hydraulic cylinder 110 retracts inward.

[0063] When the speed-regulating electro-hydraulic control system of this embodiment needs to be in the second working state, the first pilot valve 32 is opened while the second pilot valve 33 is closed. The first pilot valve 32 is open, and the pilot fluid enters the first pilot valve 32 through the fourth inlet 321 and flows out through the fourth working port 323. The first part of the pilot fluid flows into the one-way relief valve 34 through the first inlet 341 and flows out through the first outlet 342. Since the second pilot valve 33 is closed, the pilot fluid flowing out of the first outlet 342 flows into the second pilot valve 33 through the fifth working port 333 and flows back to the return pipeline 5 through the fifth return port 332. The second part of the pilot fluid enters the first directional valve 1 through the first control port 13 to form the control fluid of the first directional valve 1. Under the pressure division effect of the one-way relief valve 34, the pressure of the pilot fluid flowing into the first control port 13 is less than the pressure P0 of the pilot fluid, and the pressure of the pilot fluid flowing into the one-way relief valve 34 is less than the pressure P0 of the pilot fluid. Under the pressure control, the pressure on the left side is controlled within the preset pressure value range. The first inlet 11 is connected to the inlet pipe 4, and the first working port 14 is partially connected to the first chamber 111, so that the first reversing valve 1 is in the second state. The third part of the pilot liquid enters the third reversing valve 31 through the third control port 313 to form the control liquid of the third reversing valve 31. Under the pressure division of the one-way overflow valve 34, the pressure of the pilot liquid flowing into the third control port 313 can also push the third reversing valve 31 to switch. That is, the pressure of the pilot liquid under the pressure division of the one-way overflow valve 34 is greater than the control pressure of the third reversing valve 31. The initial state of the third reversing valve 31 is the liquid inlet state. After switching under the action of the first pilot valve 32, it becomes the liquid return state. The third reversing valve 31 no longer provides control liquid to the second reversing valve 2, so that the second reversing valve 2 is in the fifth state, and the piston rod 114 slowly extends.

[0064] When the speed-regulating electro-hydraulic control system of this embodiment needs to be in the third working state, the first pilot valve 32 and the second pilot valve 33 are opened simultaneously. The pilot fluid of the first pilot valve 32 enters the first control port 13 and the third control port 313, and the pilot fluid of the second pilot valve 33 enters the third inlet port 311. Since the first inlet 341 of the one-way overflow valve 34 is connected to the fourth working port 323, the first control port 13 and the third control port 313, and the first outlet 342 is connected to the fifth working port 333 and the third inlet port 311, the first inlet of the one-way overflow valve 34 is connected to the fourth working port 323, the first control port 13 and the third control port 313. The pilot fluid pressures at both ends of port 341 and the first outlet 342 are the same, both being P0. The one-way relief valve 34 is in an inactive state. The pilot fluid pressure flowing from the fourth working port 323 to the first control port 13 remains at P0, causing the first directional valve 1 to be in the third state. Moreover, since the first pilot valve 32 is open, the pilot fluid from the fourth working port 323 enters the third control port 313, causing the third directional valve 31 to be in a return state. The third directional valve 31 no longer supplies control fluid to the second directional valve 2, causing the second directional valve 2 to be in the fifth state, and the piston rod 114 extends rapidly.

[0065] Therefore, the speed-regulating electro-hydraulic control system of this embodiment controls the opening area of ​​the first inlet 11 by controlling the control fluid entering the first control port 13 at different pressures, realizing zero flow, small flow and full flow of fluid into the first inlet 11, making the flow adjustment of the first reversing valve 1 more convenient. At the same time, as long as the first pilot valve 32 is opened, the third reversing valve 31 switches to the setting mode of being in the return fluid state. However, the return fluid state of the third reversing valve 31 cannot provide control fluid to the second reversing valve 2, causing the second reversing valve 2 to be in the fifth state. Only when the second reversing valve 2 is opened alone and the first reversing valve 1 is closed can the second reversing valve 2 be in the adjustment mode of the fourth state. The three working states of the speed-regulating electro-hydraulic control system can be switched quickly.

[0066] It should be noted that when the first pilot valve 32 and the second pilot valve 33 are opened simultaneously, the first pilot valve 32 controls the third control port 313 of the third directional valve 31, which connects the third working port 314 with the third return port 312 and disconnects the third inlet port 311 from the third working port 314. The second pilot valve 33 controls the third inlet port 311 of the third directional valve 31, and the third directional valve 31 controls the second control port 23 of the second directional valve 2. The pilot fluid flowing out of the fifth working port 333 of the second pilot valve 33 cannot enter the third inlet port 311 of the third directional valve 31, nor can it flow through the third working port 314 to the second control port 23 of the second directional valve 2. In other words, as long as the first pilot valve 32 is open, regardless of whether the second pilot valve 33 is open or closed, the third directional valve 31 is in the return state, which in turn makes the second directional valve 2 in the fifth state.

[0067] Furthermore, by setting a one-way overflow valve 34 to divide the pressure entering the first control port 13, it is possible to switch between the three working states by only controlling the opening and closing of the first pilot valve 32 and the second pilot valve 33. This makes the speed regulation electro-hydraulic control system of the present invention simple in structure and convenient in control and adjustment.

[0068] In some embodiments, the control system 3 further includes a controller 35, which may be connected to a first pilot valve 32 to connect a fourth working port 323 to a fourth inlet port 321, and when the controller 35 is disconnected from the first pilot valve 32, the fourth working port 323 is connected to a fourth return port 322; and / or, the controller 35 may be connected to a second pilot valve 33 to connect a fifth working port 333 to a fifth inlet port 331, and when the controller 35 is disconnected from the second pilot valve 33, the fifth working port 333 is connected to a fifth return port 332.

[0069] Specifically, the controller 35 is electrically connected to the first pilot valve 32. When the controller 35 is connected to the first pilot valve 32, the first pilot valve 32 is in the liquid inlet state. When the second pilot valve 33 is closed, due to the pressure division effect of the one-way relief valve 34, the pressure entering the first control port 13 through the first pilot valve 32 is less than the pressure of the liquid inlet pipeline 4. The first directional valve 1 starts at a small flow rate and is in the second state. At the same time, the third directional valve 31 is in the liquid return state, and the second directional valve 2 is in the fifth state. When the controller 35 is disconnected from the first pilot valve 32, the first pilot valve 32 is in the liquid return state.

[0070] The controller 35 is electrically connected to the second pilot valve 33. When the controller 35 is connected to the second pilot valve 33, the second pilot valve 33 is in the fluid inlet state. When the first pilot valve 32 is open, the second pilot valve 33 maintains the same pressure at the first inlet 341 and the first outlet 342 of the one-way relief valve 34, ensuring that the pressure entering the first control port 13 through the first pilot valve 32 is the same as the pressure in the fluid inlet pipe 4, thereby enabling the first directional valve 1 to start at high flow rate and enter the third state. When the second pilot valve 33 is open and the first pilot valve 32 is closed, the third directional valve 31 is in the fluid inlet state, and the pilot fluid flowing out of the second pilot valve 33 flows to the second control port 23 through the third directional valve, controlling the second directional valve 2 to enter the fourth state, realizing the retraction of the hydraulic cylinder 110. When the controller 35 is disconnected from the second pilot valve 33, the second pilot valve 33 is in the fluid return state.

[0071] In some embodiments, the control system 3 further includes: a first check valve 36 disposed on the inlet line 4; and / or a second check valve 37 disposed on the return line 5; and / or a filter 38 disposed on the inlet line 4.

[0072] Specifically, the working fluid in the inlet pipe 4 flows into the first pilot valve 32 and the second pilot valve 33 respectively through the first one-way valve 36, which can effectively prevent the pilot fluid in the first pilot valve 32 and the second pilot valve 33 from flowing back into the inlet pipe 4 and contaminating the working fluid in the inlet pipe 4, thereby improving the working reliability of the embodiment of the present invention.

[0073] The control fluid flowing out of the first pilot valve 32 and the second pilot valve 33, as well as the return fluid flowing out of the third directional valve 31, flows to the return fluid line 5 via the second check valve 37. This effectively prevents the working fluid in the return fluid line 5 from flowing back into the first pilot valve 32 and the second pilot valve 33, further improving the operational reliability of this embodiment of the invention.

[0074] The working fluid flowing out of the first one-way valve 36 is filtered by the filter 38 and then enters the first pilot valve 32 and the second pilot valve 33 respectively. By setting the filter 38 to filter the working fluid in the inlet pipe 4, impurities in the working fluid in the inlet pipe 4 can be effectively prevented from clogging the first pilot valve 32 or the second pilot valve 33, thereby further improving the working reliability of the embodiment of the present invention.

[0075] It is understood that the embodiments of the present invention do not limit the specific structure of the first reversing valve 1, the second reversing valve 2, the third reversing valve 31, the first pilot valve 32, the second pilot valve 33, the one-way relief valve 34, the first one-way valve 36, the second one-way valve 37, and the filter 38. Among them, the third reversing valve 31 is a normally open two-position three-way valve, and the second reversing valve 2 is a normally closed two-position three-way valve. As long as they conform to the functional symbols of the embodiments of the present invention and satisfy the functions of the embodiments of the present invention, they are all within the protection scope of the embodiments of the present invention.

[0076] Optionally, each of the first reversing valve 1, the second reversing valve 2, the third reversing valve 31, the first pilot valve 32, the second pilot valve 33, the one-way relief valve 34, the first one-way valve 36, the second one-way valve 37, and the filter 38 is integrated into a module, thereby making the speed regulation electro-hydraulic control system of the present invention compact and easy to replace.

[0077] This invention also proposes the application of a speed-regulating electro-hydraulic control system, which is used to control the hydraulic cylinder 110 or the hydraulic motor 120.

[0078] Specifically, such as Figure 1 and Figure 2 As shown, the speed-regulating electro-hydraulic control system can be applied to the hydraulic cylinder 110 or the hydraulic motor 120 to improve the control accuracy of the hydraulic cylinder 110 or the hydraulic motor 120.

[0079] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0080] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0081] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0082] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first and second features are in direct contact, or that they are in indirect contact through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0083] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0084] It is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A speed-regulating electro-hydraulic control system, characterized in that, include: A first directional valve has a first inlet and a first return port. The first directional valve is switchable between a first state, a second state, and a third state. In the first state, the first return port is adapted to communicate with a first chamber of an actuator. In the second state, a portion of the first inlet is communicated with the first chamber. In the third state, the entire first inlet is communicated with the first chamber. The second directional valve has a second inlet and a second return port. The second directional valve is switchable between a fourth state and a fifth state. In the fourth state, the second inlet is connected to the second chamber of the actuator. In the fifth state, the second return port is connected to the second chamber. A control system, the control system including a third directional valve, the third directional valve being connected to a second directional valve to control the second directional valve to switch between the fourth state and the fifth state, the control system also being used to control the first directional valve to switch between the first state, the second state and the third state. The second reversing valve has a second control port and a second working port, and the third reversing valve has a third inlet port, a third return port and a third working port. The second working port is connected to the second chamber, and the third working port is connected to the second control port. When the third working port is connected to the third inlet port, the second reversing valve is in a fourth state. When the third working port is connected to the third return port, the second reversing valve is in a fifth state. The system also includes an inlet pipeline and a return pipeline. The control system further includes a first pilot valve, which has a fourth inlet port, a fourth return port, and a fourth working port. The first directional valve has a first control port, and the third directional valve has a third control port. The fourth inlet port is connected to the inlet pipeline, and the fourth return port is connected to the return pipeline. The fourth working port is connected to both the first control port and the third control port so that the first directional valve is in a second or third state while the third working port of the third directional valve is connected to the third return port, and the third return port is connected to the return pipeline.

2. The speed-regulating electro-hydraulic control system according to claim 1, characterized in that, The second inlet is connected to the inlet pipeline, and the second return outlet is connected to the return pipeline. In the fourth state, the second working port is connected to the second inlet. In the fifth state, the second working port is connected to the second return outlet.

3. The speed-regulating electro-hydraulic control system according to claim 2, characterized in that, The first reversing valve has a first working port, which is connected to the first chamber, a first liquid inlet connected to the liquid inlet pipeline, and a first liquid return port connected to the liquid return pipeline. In the first state, the first working port is connected to the first liquid return port. In the second state, the first working port is connected to a portion of the first liquid inlet. In the third state, the first working port is fully connected to the first liquid inlet.

4. The speed-regulating electro-hydraulic control system according to claim 1, characterized in that, The control system further includes a second pilot valve, which has a fifth inlet, a fifth return port, and a fifth working port. The fifth inlet is connected to the inlet pipeline, the fifth return port is connected to the return pipeline, and the fifth working port is connected to the third inlet.

5. The speed-regulating electro-hydraulic control system according to claim 4, characterized in that, The control system further includes a one-way overflow valve, which has a first inlet and a first outlet. The first inlet is connected to the fourth working port, the first control port and the third control port, and the first outlet is connected to the fifth working port and the third liquid inlet.

6. The speed-regulating electro-hydraulic control system according to claim 4, characterized in that, The control system further includes a controller, which can be connected to the first pilot valve to connect the fourth working port to the fourth inlet port, and when the controller is disconnected from the first pilot valve, the fourth working port is connected to the fourth return port; and / or, The controller can be connected to the second pilot valve to connect the fifth working port to the fifth inlet port, and when the controller is disconnected from the second pilot valve, the fifth working port is connected to the fifth return port.

7. The speed-regulating electro-hydraulic control system according to claim 2, characterized in that, The control system further includes: a first check valve, wherein the first check valve is disposed on the inlet pipeline; and / or A second check valve is provided on the return line; and / or A filter is provided on the inlet pipe.

8. An application of the speed-regulating electro-hydraulic control system according to any one of claims 1-7, characterized in that, The speed-regulating electro-hydraulic control system is used to control hydraulic cylinders or hydraulic motors.

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