Proportional pressure valve with pressure closed loop and hydraulic control system

Abstract

The utility model provides a proportional pressure valve with a pressure closed loop and a hydraulic control system. The proportional pressure valve with the pressure closed loop comprises a main valve part, a pilot valve part, a pressure sensor and a control unit. The main valve part comprises a main valve body, a main valve element and a main valve reset spring. A main valve cavity and a spring cavity are formed in the main valve element. The main valve cavity is isolated from the spring cavity through the main valve element, and the main valve oil inlet is communicated with the spring cavity through a pilot control oil way. A proportional electromagnet of the pilot valve part controls the opening pressure of the pilot valve part based on the input; under the condition that the hydraulic oil pressure of the main valve oil inlet is larger than the opening pressure of the pilot valve part, the pilot valve part enables hydraulic oil in the spring cavity to be discharged, so that the main valve element moves to the opening position; the pressure sensor obtains the real-time pressure of hydraulic oil in the pilot control oil way; the control unit controls input of the proportional electromagnet based on the real-time pressure, obtained by the pressure sensor, of the hydraulic oil in the pilot control oil way, so that the real-time pressure of the hydraulic oil in the pilot control oil way is kept at the set pressure.

Description

Technical Field

[0001] The present disclosure relates to the field of hydraulic equipment, and more precisely, to a proportional pressure valve with a pressure closed-loop, and also to a hydraulic control system. Background Art

[0002] The function of a conventional proportional pressure valve is mostly to control the working pressure of a hydraulic system and can protect the actuator. However, the existing proportional pressure valve has poor control accuracy and is not easy to meet the requirements. Therefore, there is an urgent need to invent a proportional pressure valve with higher accuracy. Summary of the Utility Model

[0003] The present disclosure provides a proportional pressure valve with a pressure closed-loop to solve the problems existing in the prior art.

[0004] According to a first aspect of the present disclosure, there is provided a proportional pressure valve with a pressure closed-loop, comprising:

[0005] A main valve part, the main valve part includes a main valve body, a main valve core and a main valve return spring. A main valve cavity and a spring cavity are formed in the main valve core; the main valve cavity and the spring cavity are isolated from each other by the main valve core;

[0006] A main valve inlet and a main valve outlet are respectively arranged in the main valve cavity. The main valve core has an open position and a closed position. When in the open position, the main valve inlet and the main valve outlet are communicated; when in the closed position, the main valve inlet and the main valve outlet are disconnected. The main valve return spring is located in the spring cavity and is configured to push the main valve core in the direction of the closed position. The hydraulic oil at the main valve inlet is configured to push the main valve core in the direction of the open position, and the hydraulic oil at the main valve inlet is communicated with the spring cavity through a pilot control oil circuit;

[0007] A pilot valve part, the pilot valve part at least includes a proportional electromagnet, and the proportional electromagnet is configured to control the opening pressure of the pilot valve part based on an input. The pilot valve part is configured to discharge the hydraulic oil in the spring cavity when the hydraulic oil pressure at the main valve inlet is greater than the opening pressure of the pilot valve part, so that the main valve core moves to the open position;

[0008] A pressure sensor, the pressure sensor is configured to acquire the real-time pressure of the hydraulic oil in the pilot control oil circuit;

[0009] A control unit, the control unit is configured to control the input of the proportional electromagnet based on the real-time pressure of the hydraulic oil in the pilot control oil circuit acquired by the pressure sensor, so that the real-time pressure of the hydraulic oil in the pilot control oil circuit is maintained at a set pressure.

[0010] In one embodiment of the present disclosure, the pilot valve portion further includes at least a pilot valve drain port, and the proportional electromagnet is configured to control the opening pressure of the pilot valve portion based on an input; when the hydraulic oil pressure at the main valve inlet port is greater than the opening pressure of the pilot valve portion, the hydraulic oil in the spring chamber drains out from the pilot valve drain port, so that the main valve spool moves to the opening position.

[0011] In one embodiment of the present disclosure, the pilot valve portion further includes a pilot valve body and a pilot valve spool; a pilot valve chamber is formed in the pilot valve spool, and at least a pilot valve throttle orifice is provided in the pilot valve chamber, and the pilot valve throttle orifice is configured to communicate with the main valve inlet port through the pilot control oil passage;

[0012] The pilot valve spool has a pilot closed position and a pilot open position, and the proportional electromagnet is configured to control the opening pressure for the pilot valve spool to switch from the pilot closed position to the pilot open position;

[0013] When the hydraulic oil pressure at the main valve inlet port does not reach the opening pressure, the pilot valve spool is in the pilot closed position, the pilot valve throttle orifice is closed, and the main valve spool is in the closed position;

[0014] When the hydraulic oil pressure at the main valve inlet port reaches the opening pressure, the pilot valve spool switches to the pilot open position, the pilot valve throttle orifice opens, at least part of the hydraulic oil in the spring chamber flows out from the pilot valve throttle orifice to the pilot valve drain port, and the main valve spool moves toward the opening position so that the main valve inlet port and the main valve outlet port are communicated.

[0015] In one embodiment of the present disclosure, the pilot valve spool is configured to have a tapered end and is fixedly connected to the output end of the proportional electromagnet;

[0016] The pilot valve body includes a pilot outer valve body and a pilot inner valve body, the pilot inner valve body and the pilot valve spool are both disposed in a pilot valve chamber inside the pilot outer valve body, and the pilot valve throttle orifice is formed on the pilot inner valve body;

[0017] When the pilot valve spool is in the pilot closed position, the end of the pilot valve spool is inserted into the pilot valve throttle orifice to close the pilot valve throttle orifice; when the pilot valve spool is in the pilot open position, a throttle gap is formed between the end of the pilot valve spool and the pilot valve throttle orifice to open the pilot valve throttle orifice.

[0018] In one embodiment of the present disclosure, a protection valve portion is further included;

[0019] The protection valve part includes a protection valve body, a protection valve core, and a protection spring; a protection valve cavity is formed in the protection valve core, and at least a protection valve throttle port and a protection valve oil drain port are arranged in the protection valve cavity; the protection valve throttle port is configured to communicate with the main valve oil inlet through the pilot control oil circuit, one end of the protection valve core abuts against the protection spring, and the other end cooperates with the protection valve throttle port;

[0020] When the hydraulic oil pressure at the protection valve throttle port does not reach the protection pressure, the protection valve core closes the protection valve throttle port;

[0021] When the hydraulic oil pressure at the protection valve throttle port reaches the protection pressure, the hydraulic oil in the pilot control oil circuit overcomes the elastic force of the protection spring and pushes the protection valve core to move, so that the protection valve throttle port is opened, and at least part of the hydraulic oil in the pilot control oil circuit flows out from the protection valve throttle port to the protection valve oil drain port.

[0022] In an embodiment of the present disclosure, the protection spring is configured to make the protection pressure of the protection valve throttle port greater than the maximum opening pressure of the pilot valve part.

[0023] In an embodiment of the present disclosure, a connecting member is arranged in the pilot control oil circuit, and the connecting member is respectively communicated with the pilot valve throttle port, the protection valve throttle port, the main valve oil inlet, and the spring cavity.

[0024] In an embodiment of the present disclosure, the main valve oil inlet is arranged at one axial end of the main valve core, and the main valve oil outlet is arranged at the radial side part of the main valve core.

[0025] In an embodiment of the present disclosure, the proportional electromagnet is configured to control the opening pressure of the pilot valve part based on the input current;

[0026] The control unit is configured to control the input current of the proportional electromagnet based on the real-time pressure of the hydraulic oil in the pilot control oil circuit acquired by the pressure sensor, so that the real-time pressure of the hydraulic oil in the pilot control oil circuit is maintained at the set pressure.

[0027] According to a second aspect of the present disclosure, a hydraulic control system is provided, including an oil inlet pipeline, an oil outlet pipeline, and the pressure-closed-loop proportional pressure valve, the oil inlet pipeline is communicated with the main valve oil inlet of the pressure-closed-loop proportional pressure valve, and the oil outlet pipeline is communicated with the main valve oil outlet of the pressure-closed-loop proportional pressure valve.

[0028] The present disclosure provides a pressure closed-loop proportional pressure valve, which includes a main valve part, a pilot valve part, a pressure sensor and a control unit. Among them, the main valve part includes a main valve body, a main spool and a main valve return spring. A main valve cavity and a spring cavity are formed in the main spool; the main valve cavity and the spring cavity are isolated from each other by the main spool; a main valve inlet and a main valve outlet are respectively arranged in the main valve cavity. The main spool has an open position and a closed position. In the open position, the main valve inlet and the main valve outlet are communicated. In the closed position, the main valve inlet and the main valve outlet are disconnected; the main valve return spring is located in the spring cavity and is configured to push the main spool in the direction of the closed position. The hydraulic oil at the main valve inlet is configured to push the main spool in the direction of the open position, and the main valve inlet is communicated with the spring cavity through a pilot control oil passage;

[0029] The pilot valve part at least includes a proportional electromagnet, and the proportional electromagnet is configured to control the opening pressure of the pilot valve part based on an input; the pilot valve part is configured to discharge the hydraulic oil in the spring cavity when the hydraulic oil pressure at the main valve inlet is greater than the opening pressure of the pilot valve part, so that the main spool moves to the open position;

[0030] The pressure sensor is configured to obtain the real-time pressure of the hydraulic oil in the pilot control oil passage; the control unit is configured to control the input of the proportional electromagnet based on the real-time pressure of the hydraulic oil in the pilot control oil passage obtained by the pressure sensor, so that the real-time pressure of the hydraulic oil in the pilot control oil passage is maintained at a set pressure.

[0031] During the working process of the pressure closed-loop proportional pressure valve of the present disclosure, the initial pressure at the main valve inlet is relatively low. The main spool is in the closed position under the action of the main valve return spring. The hydraulic oil at the main valve inlet pushes the main spool in the direction of the open position, and the main valve inlet is communicated with the spring cavity through the pilot control oil passage. Part of the hydraulic oil at the main valve inlet flows into the spring cavity through the pilot control oil passage. However, the pressure of the hydraulic oil at the main valve inlet is less than the sum of the elastic force of the main valve return spring and the pressure of the hydraulic oil in the spring cavity, and cannot push the main spool, so that the main spool remains in the closed position, and the pressure of the hydraulic oil at the main valve inlet continuously increases.

[0032] The proportional electromagnet can control the opening pressure of the pilot valve part based on an input; after the pressure of the hydraulic oil at the main valve inlet continuously increases to reach the opening pressure of the pilot valve part, the hydraulic oil in the spring cavity is discharged, so that the pressure of the hydraulic oil at the main valve inlet is greater than the sum of the elastic force of the main valve return spring and the pressure of the hydraulic oil in the spring cavity, thereby pushing the main spool to move to the open position, and the main valve inlet and the main valve outlet are communicated, so that the pressure of the hydraulic oil at the main valve inlet is maintained at the opening pressure of the pilot valve part.

[0033] Among them, the pressure sensor can obtain the real-time pressure of the hydraulic oil in the pilot control oil circuit, and the control unit can control the input of the proportional electromagnet based on the real-time pressure of the hydraulic oil in the pilot control oil circuit obtained by the pressure sensor, so as to adjust the opening pressure of the pilot valve part, so that the real-time pressure of the hydraulic oil in the pilot control oil circuit is maintained at the set pressure.

[0034] Specifically, when the real-time pressure of the hydraulic oil in the pilot control oil circuit is lower than the set pressure, the control unit can control the input of the proportional electromagnet to increase the real-time pressure of the hydraulic oil in the pilot control oil circuit until the real-time pressure of the hydraulic oil in the pilot control oil circuit reaches the set pressure. When the real-time pressure of the hydraulic oil in the pilot control oil circuit is higher than the set pressure, the control unit can control the input of the proportional electromagnet to decrease the real-time pressure of the hydraulic oil in the pilot control oil circuit until the real-time pressure of the hydraulic oil in the pilot control oil circuit reaches the set pressure.

[0035] Compared with the existing proportional pressure valve, the pressure closed-loop proportional pressure valve of the present disclosure can utilize the pressure sensor and the control unit to closed-loop control the real-time pressure of the hydraulic oil in the pilot control oil circuit, and then control the pressure of the hydraulic oil at the main valve inlet. The control pressure linearity, hysteresis, and control accuracy are greatly improved compared with the existing proportional pressure valve. The response speed is fast, and the dynamic characteristics are greatly improved. It can be applied to occasions with higher control accuracy requirements, especially can be widely applied to the automation control of various equipment such as metallurgy, power generation, petrochemical, intelligent manufacturing, machine tools, intelligent devices, energy transportation, engineering equipment, and testing machines.

[0036] Other features and advantages of the present disclosure will become clear through the following detailed description of the exemplary embodiments of the present disclosure with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The drawings incorporated in the specification and constituting a part of the specification illustrate embodiments of the present disclosure and, together with the description, are used to explain the principles of the present disclosure.

[0038] Figure 1 is a schematic cross-sectional view of the pressure closed-loop proportional pressure valve provided by the embodiment of the present disclosure;

[0039] Figure 2 is a schematic diagram of relevant data of the existing proportional pressure valve;

[0040] Figure 3 is a schematic diagram of relevant data of the pressure closed-loop proportional pressure valve of the present disclosure.

[0041] Figure 1 The corresponding relationship between the names of the components and the reference numerals in is as follows:

[0042] 10. Main valve section; 11. Main valve body; 12. Main spool; 13. Main valve return spring; 14. Main valve cavity; 141. Main valve oil inlet; 142. Main valve oil outlet; 15. Spring cavity; 20. Pilot valve section; 21. Proportional electromagnet; 22. Pilot valve oil drain port; 23. Pilot valve body; 231. Pilot outer valve body; 232. Pilot inner valve body; 24. Pilot spool; 25. Pilot valve throttle orifice; 30. Pilot control oil circuit; 31. Connecting member; 40. Pressure sensor; 50. Protection valve section; 51. Protection valve body; 52. Protection spool; 53. Protection spring; 54. Protection valve cavity; 541. Protection valve throttle orifice; 542. Protection valve oil drain port. Detailed implementation manners

[0043] Now, various exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. It should be noted that: unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions and values set forth in these embodiments do not limit the scope of the present disclosure. In all the examples shown and discussed herein, any specific value should be construed as merely exemplary, rather than as a limitation. Therefore, other examples of the exemplary embodiments may have different values.

[0044] Numerous specific details are set forth in the following description in order to provide a thorough understanding of the present disclosure. However, the present disclosure can be implemented in many other ways different from those described herein, and those skilled in the art can make similar generalizations without departing from the spirit of the present disclosure. Therefore, the present disclosure is not limited by the specific implementations disclosed below. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and devices should be regarded as part of the specification.

[0045] The terms used in one or more embodiments of the present disclosure are for the purpose of describing specific embodiments only and are not intended to limit one or more embodiments of the present disclosure. The singular forms "a", "the", and "said" used in one or more embodiments of the present disclosure and the appended claims are also intended to include the plural forms unless the context clearly dictates otherwise. It should also be understood that the term "and / or" used in one or more embodiments of the present disclosure refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0046] It should be understood that although the terms first, second, etc. may be used in one or more embodiments of the present disclosure to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of one or more embodiments of the present disclosure, the first may also be referred to as the second, and similarly, the second may also be referred to as the first. Depending on the context, the word "if" as used herein may be interpreted as "when" or "while" or "in response to determining". In this article, "upper", "lower", "front", "rear", "left", "right", etc. are only used to represent the relative positional relationship between relevant parts, rather than defining the absolute positions of these relevant parts. In this article, "equal", "same", etc. are not strict mathematical and / or geometric limitations, and also include errors that can be understood by those skilled in the art and are allowed in manufacturing or using, etc. Unless otherwise specified, the numerical ranges in this article include not only the entire range within its two endpoints, but also several sub-ranges included therein.

[0047] The present disclosure provides a pressure closed-loop proportional pressure valve, including a main valve part, a pilot valve part, a pressure sensor and a control unit. Among them, the main valve part includes a main valve body, a main valve core and a main valve return spring. A main valve cavity and a spring cavity are formed in the main valve core; the main valve cavity and the spring cavity are isolated from each other by the main valve core; a main valve oil inlet and a main valve oil outlet are respectively arranged in the main valve cavity. The main valve core has an open position and a closed position. In the open position, the main valve oil inlet and the main valve oil outlet are communicated. In the closed position, the main valve oil inlet and the main valve oil outlet are disconnected; the main valve return spring is located in the spring cavity and is configured to push the main valve core in the direction of the closed position. The hydraulic oil at the main valve oil inlet is configured to push the main valve core in the direction of the open position, and the main valve oil inlet is communicated with the spring cavity through a pilot control oil circuit;

[0048] The pilot valve part at least includes a proportional electromagnet, and the proportional electromagnet is configured to control the opening pressure of the pilot valve part based on an input; the pilot valve part is configured to discharge the hydraulic oil in the spring cavity when the hydraulic oil pressure at the main valve oil inlet is greater than the opening pressure of the pilot valve part, so as to move the main valve core to the open position;

[0049] The pressure sensor is configured to obtain the real-time pressure of the hydraulic oil in the pilot control oil circuit; the control unit is configured to control the input of the proportional electromagnet based on the real-time pressure of the hydraulic oil in the pilot control oil circuit obtained by the pressure sensor, so as to keep the real-time pressure of the hydraulic oil in the pilot control oil circuit at a set pressure.

[0050] During the operation of the pressure closed-loop proportional pressure valve of the present disclosure, the initial pressure at the main valve inlet is relatively low. The main valve spool is in the closed position under the action of the main valve return spring. The hydraulic oil at the main valve inlet pushes the main valve spool in the direction of the open position. The main valve inlet is connected to the spring chamber through the pilot control oil circuit. Part of the hydraulic oil at the main valve inlet flows through the pilot control oil circuit into the spring chamber. However, the pressure of the hydraulic oil at the main valve inlet is less than the sum of the elastic force of the main valve return spring and the pressure of the hydraulic oil in the spring chamber, and thus cannot push the main valve spool. As a result, the main valve spool remains in the closed position, and the pressure of the hydraulic oil at the main valve inlet continuously increases.

[0051] The proportional electromagnet can control the opening pressure of the pilot valve section based on the input. After the pressure of the hydraulic oil at the main valve inlet continuously increases to reach the opening pressure of the pilot valve section, the hydraulic oil in the spring chamber is drained, so that the pressure of the hydraulic oil at the main valve inlet is greater than the sum of the elastic force of the main valve return spring and the pressure of the hydraulic oil in the spring chamber, thereby pushing the main valve spool to move to the open position. The main valve inlet and the main valve outlet are connected, so that the pressure of the hydraulic oil at the main valve inlet is maintained at the opening pressure of the pilot valve section.

[0052] Among them, the pressure sensor can obtain the real-time pressure of the hydraulic oil in the pilot control oil circuit. The control unit can control the input of the proportional electromagnet based on the real-time pressure of the hydraulic oil in the pilot control oil circuit obtained by the pressure sensor, so as to adjust the opening pressure of the pilot valve section, so that the real-time pressure of the hydraulic oil in the pilot control oil circuit is maintained at the set pressure.

[0053] Specifically, when the real-time pressure of the hydraulic oil in the pilot control oil circuit is lower than the set pressure, the control unit can control the input of the proportional electromagnet to increase the real-time pressure of the hydraulic oil in the pilot control oil circuit until the real-time pressure of the hydraulic oil in the pilot control oil circuit reaches the set pressure. When the real-time pressure of the hydraulic oil in the pilot control oil circuit is higher than the set pressure, the control unit can control the input of the proportional electromagnet to reduce the real-time pressure of the hydraulic oil in the pilot control oil circuit until the real-time pressure of the hydraulic oil in the pilot control oil circuit reaches the set pressure.

[0054] Compared with the existing proportional pressure valve, the pressure closed-loop proportional pressure valve of the present disclosure can use the pressure sensor and the control unit to closed-loop control the real-time pressure of the hydraulic oil in the pilot control oil circuit, and then control the pressure of the hydraulic oil at the main valve inlet. The control pressure linearity, hysteresis, and control accuracy are greatly improved compared with the existing proportional pressure valve. The response speed is relatively fast, and the dynamic characteristics are greatly improved. It can be applied to occasions with higher control accuracy requirements. In particular, it can be widely applied to the automation control of various equipment such as metallurgy, power generation, petrochemical, intelligent manufacturing, machine tools, intelligent devices, energy transportation, engineering equipment, and testing machines.

[0055] For the sake of easy understanding, the following is referred toFigures 1 to 3 Specific structures and working principles of the pressure closed-loop proportional pressure valve of the present disclosure will be described in detail in conjunction with an embodiment.

[0056] The present disclosure provides a pressure closed-loop proportional pressure valve, including a main valve portion 10, a pilot valve portion 20, a pressure sensor 40, and a control unit. Among them, the main valve portion 10 includes a main valve body 11, a main valve spool 12, and a main valve return spring 13. A main valve chamber 14 and a spring chamber 15 are formed in the main valve spool 12; the main valve chamber 14 and the spring chamber 15 are isolated from each other by the main valve spool 12; a main valve inlet 141 and a main valve outlet 142 are respectively arranged in the main valve chamber 14. The main valve spool 12 has an open position and a closed position. In the open position, the main valve inlet 141 and the main valve outlet 142 are communicated. In the closed position, the main valve inlet 141 and the main valve outlet 142 are disconnected; the main valve return spring 13 is located in the spring chamber 15 and is configured to push the main valve spool 12 in the direction of the closed position. The hydraulic oil at the main valve inlet 141 is configured to push the main valve spool 12 in the direction of the open position, and the main valve inlet 141 is communicated with the spring chamber 15 through a pilot control oil passage 30;

[0057] The pilot valve portion 20 at least includes a proportional electromagnet 21, and the proportional electromagnet 21 is configured to control the opening pressure of the pilot valve portion 20 based on an input; the pilot valve portion 20 is configured to discharge the hydraulic oil in the spring chamber 15 when the hydraulic oil pressure at the main valve inlet 141 is greater than the opening pressure of the pilot valve portion 20, so as to move the main valve spool 12 to the open position;

[0058] The pressure sensor 40 is configured to obtain the real-time pressure of the hydraulic oil in the pilot control oil passage 30; the control unit is configured to control the input of the proportional electromagnet 21 based on the real-time pressure of the hydraulic oil in the pilot control oil passage 30 obtained by the pressure sensor 40, so as to keep the real-time pressure of the hydraulic oil in the pilot control oil passage 30 at a set pressure.

[0059] During the working process of the pressure closed-loop proportional pressure valve of the present disclosure, the initial pressure at the main valve inlet 141 is relatively low. The main valve spool 12 is in the closed position under the action of the main valve return spring 13. The hydraulic oil at the main valve inlet 141 pushes the main valve spool 12 in the direction of the open position, and the main valve inlet 141 is communicated with the spring chamber 15 through the pilot control oil passage 30. Part of the hydraulic oil at the main valve inlet 141 flows into the spring chamber 15 through the pilot control oil passage 30. However, the pressure of the hydraulic oil at the main valve inlet 141 is less than the sum of the elastic force of the main valve return spring 13 and the pressure of the hydraulic oil in the spring chamber 15, and cannot push the main valve spool 12. Thus, the main valve spool 12 remains in the closed position, and the hydraulic oil pressure at the main valve inlet 141 continuously increases.

[0060] The proportional electro-magnet 21 can control the opening pressure of the pilot valve portion 20 based on an input. After the hydraulic oil pressure at the main valve inlet 141 continuously rises to reach the opening pressure of the pilot valve portion 20, the hydraulic oil in the spring chamber 15 is drained, so that the hydraulic oil pressure at the main valve inlet 141 is greater than the sum of the elastic force of the main valve return spring 13 and the hydraulic oil pressure in the spring chamber 15, thereby pushing the main valve core 12 to move to the open position, and the main valve inlet 141 and the main valve outlet 142 are communicated, so that the hydraulic oil pressure at the main valve inlet 141 is maintained at the opening pressure of the pilot valve portion 20.

[0061] Among them, the pressure sensor 40 can obtain the real-time pressure of the hydraulic oil in the pilot control oil circuit 30, and the control unit can control the input of the proportional electro-magnet 21 based on the real-time pressure of the hydraulic oil in the pilot control oil circuit 30 obtained by the pressure sensor 40, so as to adjust the opening pressure of the pilot valve portion 20 in the direction of reducing the deviation between the real-time pressure and the set pressure, so that the real-time pressure of the hydraulic oil in the pilot control oil circuit 30 is maintained at the set pressure.

[0062] Specifically, when the real-time pressure of the hydraulic oil in the pilot control oil circuit 30 is lower than the set pressure, the control unit can control the input of the proportional electro-magnet 21 to increase the real-time pressure of the hydraulic oil in the pilot control oil circuit 30 until the real-time pressure of the hydraulic oil in the pilot control oil circuit 30 reaches the set pressure. When the real-time pressure of the hydraulic oil in the pilot control oil circuit 30 is higher than the set pressure, the control unit can control the input of the proportional electro-magnet 21 to reduce the real-time pressure of the hydraulic oil in the pilot control oil circuit 30 until the real-time pressure of the hydraulic oil in the pilot control oil circuit 30 reaches the set pressure.

[0063] Compared with the existing proportional pressure valve, the pressure closed-loop proportional pressure valve of the present disclosure can use the pressure sensor 40 and the control unit to closed-loop control the real-time pressure of the hydraulic oil in the pilot control oil circuit 30, and then control the hydraulic oil pressure at the main valve inlet 141. The control pressure linearity, hysteresis, and control accuracy are greatly improved compared with the existing proportional pressure valve. The response speed is faster, and the dynamic characteristics are greatly improved. It can be applied to occasions with higher control accuracy requirements, especially can be widely used in the automation control of various equipment such as metallurgy, power generation, petrochemical, intelligent manufacturing, machine tools, intelligent devices, energy transportation, engineering equipment, testing machines, etc.

[0064] Specifically, the maximum working pressure of the pressure closed-loop proportional pressure valve of the present disclosure can reach 35 MPa, and the maximum flow rate can reach 600 L / min; the range of hysteresis is ±0.5% of the maximum adjustment pressure; the repeatability accuracy is ±0.2% of the maximum adjustment pressure, and the linearity is ±1.0% of the maximum adjustment pressure.

[0065] The relevant data of the existing proportional pressure valve are as shown in Table 1 andFigure 2 The relevant data of the pressure closed-loop proportional pressure valve of the present disclosure are as shown in Table 1 below and Figure 3 .

[0066]

[0067] Table 1

[0068] It can be seen that compared with the existing proportional pressure valve, the hysteresis, repeatability accuracy, and linearity of the pressure closed-loop proportional pressure valve of the present disclosure are greatly improved, and the dynamic response is greatly accelerated.

[0069] In an embodiment of the present disclosure, the proportional solenoid 21 is configured to control the opening pressure of the pilot valve portion 20 based on the input current; the control unit is configured to control the input current of the proportional solenoid 21 based on the real-time pressure of the hydraulic oil in the pilot control oil passage 30 obtained by the pressure sensor 40, so that the real-time pressure of the hydraulic oil in the pilot control oil passage 30 is maintained at the set pressure. That is, the output pressure of the proportional solenoid 21 and the current command signal are linearly related, and it is more convenient to control the opening pressure for the pilot valve core 24 to switch from the pilot closed position to the pilot open position based on the input current, and the adjustment accuracy is high.

[0070] As Figure 1 shown, in an embodiment of the present disclosure, the pilot valve portion 20 further includes a pilot valve drain port 22, and the proportional solenoid 21 is configured to control the opening pressure of the pilot valve portion 20 based on the input; when the hydraulic oil pressure at the main valve inlet 141 is greater than the opening pressure of the pilot valve portion 20, the hydraulic oil in the spring chamber 15 drains out from the pilot valve drain port 22, so that the main valve core 12 moves to the open position.

[0071] That is, during the working process of the pressure closed-loop proportional pressure valve of the present disclosure, after the hydraulic oil pressure at the main valve inlet 141 continuously rises to reach the opening pressure of the pilot valve portion 20, the hydraulic oil in the spring chamber 15 flows to the pilot valve portion 20 and drains out from the pilot valve drain port 22, so that the pressure of the hydraulic oil at the main valve inlet 141 is greater than the sum of the elastic force of the main valve return spring 13 and the hydraulic oil pressure in the spring chamber 15, thereby pushing the main valve core 12 to move to the open position, and the main valve inlet 141 and the main valve outlet 142 are connected, so that the pressure of the hydraulic oil at the main valve inlet 141 is maintained at the opening pressure of the pilot valve portion 20.

[0072] Specifically, as Figure 1 shown, in an embodiment of the present disclosure, the pilot valve portion 20 further includes a pilot valve body 23 and a pilot valve core 24; a pilot valve chamber is formed in the pilot valve core 24, and at least a pilot valve throttle port 25 is provided in the pilot valve chamber, and the pilot valve throttle port 25 is configured to be connected to the main valve inlet 141 through the pilot control oil passage 30;

[0073] The pilot spool 24 has a pilot closed position and a pilot open position, and the proportional solenoid 21 is configured to control the opening pressure for the pilot spool 24 to switch from the pilot closed position to the pilot open position;

[0074] When the hydraulic oil pressure at the main valve inlet port 141 does not reach the opening pressure, the pilot spool 24 is in the pilot closed position, the pilot valve throttle orifice 25 is closed, and the main spool 12 is in the closed position;

[0075] When the hydraulic oil pressure at the main valve inlet port 141 reaches the opening pressure, the pilot spool 24 switches to the pilot open position, the pilot valve throttle orifice 25 opens, and at least part of the hydraulic oil in the spring chamber 15 flows out from the pilot valve throttle orifice 25 to the pilot valve drain port 22, and the main spool 12 moves towards the open position to connect the main valve inlet port 141 and the main valve outlet port 142.

[0076] During the working process of the pressure closed-loop proportional pressure valve of the present disclosure, the initial pressure at the main valve inlet port 141 is relatively low. The main spool 12 is in the closed position under the action of the main valve return spring 13. The hydraulic oil at the main valve inlet port 141 pushes the main spool 12 in the direction of the open position. Moreover, the main valve inlet port 141 is connected to the spring chamber 15 through the pilot control oil passage 30. Part of the hydraulic oil at the main valve inlet port 141 flows through the pilot control oil passage 30 into the spring chamber 15. However, the hydraulic oil pressure at the main valve inlet port 141 does not reach the opening pressure. The pilot spool 24 is in the pilot closed position, the pilot valve throttle orifice 25 closes. The pressure of the hydraulic oil at the main valve inlet port 141 is less than the sum of the elastic force of the main valve return spring 13 and the hydraulic oil pressure in the spring chamber 15, and thus cannot push the main spool 12, so that the main spool 12 remains in the closed position, and the hydraulic oil pressure at the main valve inlet port 141 continuously increases.

[0077] After the hydraulic oil pressure at the main valve inlet port 141 continuously increases to reach the opening pressure of the pilot valve section 20, the pilot spool 24 switches to the pilot open position, the pilot valve throttle orifice 25 opens, and at least part of the hydraulic oil in the spring chamber 15 flows out from the pilot valve throttle orifice 25 to the pilot valve drain port 22. Thus, the pressure of the hydraulic oil at the main valve inlet port 141 is greater than the sum of the elastic force of the main valve return spring 13 and the hydraulic oil pressure in the spring chamber 15, thereby pushing the main spool 12 to move to the open position, connecting the main valve inlet port 141 and the main valve outlet port 142, and thus keeping the pressure of the hydraulic oil at the main valve inlet port 141 at the opening pressure of the pilot valve section 20.

[0078] As Figure 1As shown, in an embodiment of the present disclosure, the pilot spool 24 is configured with a tapered end and is fixedly connected to the output end of the proportional solenoid 21; the pilot valve body 23 includes a pilot outer valve body 231 and a pilot inner valve body 232. The pilot inner valve body 232 and the pilot spool 24 are both disposed in the pilot valve cavity inside the pilot outer valve body 231, and the pilot valve throttle orifice 25 is formed on the pilot inner valve body 232. When the pilot spool 24 is in the pilot closed position, the end of the pilot spool 24 is inserted into the pilot valve throttle orifice 25 to close the pilot valve throttle orifice 25. When the pilot spool 24 is in the pilot open position, a throttling gap is formed between the end of the pilot spool 24 and the pilot valve throttle orifice 25 to open the pilot valve throttle orifice 25.

[0079] When it is necessary to place the pilot spool 24 in the pilot closed position, the tapered end of the pilot spool 24 is inserted into the pilot valve throttle orifice 25 to close the pilot valve throttle orifice 25 and prevent leakage. When it is necessary for the pilot spool 24 to be in the pilot open position, the tapered end of the pilot spool 24 can quickly form a throttling gap with the pilot valve throttle orifice 25 to facilitate the quick opening of the pilot valve throttle orifice 25.

[0080] As Figure 1 shown, in an embodiment of the present disclosure, the pressure-closed-loop proportional pressure valve of the present disclosure further includes a protection valve portion 50; the protection valve portion 50 includes a protection valve body 51, a protection spool 52, and a protection spring 53. A protection valve cavity 54 is formed in the protection spool 52, and at least a protection valve throttle orifice 541 and a protection valve oil drain port 542 are provided in the protection valve cavity 54. The protection valve throttle orifice 541 is configured to communicate with the main valve inlet port 141 through the pilot control oil passage 30. One end of the protection spool 52 abuts against the protection spring 53, and the other end cooperates with the protection valve throttle orifice 541.

[0081] When the hydraulic oil pressure at the protection valve throttle orifice 541 does not reach the protection pressure, the protection spool 52 closes the protection valve throttle orifice 541.

[0082] When the hydraulic oil pressure at the protection valve throttle orifice 541 reaches the protection pressure, the hydraulic oil in the pilot control oil passage 30 overcomes the elastic force of the protection spring 53 and pushes the protection spool 52 to move, so that the protection valve throttle orifice 541 is opened, and at least part of the hydraulic oil in the pilot control oil passage 30 flows out from the protection valve throttle orifice 541 to the protection valve oil drain port 542.

[0083] During the operation of the pressure closed-loop proportional pressure valve of the present disclosure, when the hydraulic oil pressure at the throttle orifice 541 of the protection valve does not reach the protection pressure, the protection valve core 52 closes the throttle orifice 541 of the protection valve, and the hydraulic oil in the pilot control oil circuit 30 will not flow out from the protection valve portion 50. When a fault occurs in structures such as the pilot valve portion 20, resulting in a sudden increase in the hydraulic oil pressure in the pilot control oil circuit 30, and when the hydraulic oil pressure at the throttle orifice 541 of the protection valve reaches the opening pressure, the hydraulic oil in the pilot control oil circuit 30 can overcome the elastic force of the protection spring 53, push the protection valve core 52 to move, so that the throttle orifice 541 of the protection valve opens, and at least part of the hydraulic oil in the pilot control oil circuit 30 flows out from the throttle orifice 541 of the protection valve to the protection valve oil drain port 542, thereby discharging part of the pressure of the hydraulic oil in the pilot control oil circuit 30, making the pressure of the hydraulic oil in the pilot control oil circuit 30 below the protection pressure, preventing the hydraulic oil pressure in the pilot control oil circuit 30 from being too high, and avoiding abnormal leakage or even explosion, etc., ensuring that the pressure closed-loop proportional pressure valve of the present disclosure can work properly.

[0084] It can be understood that, in an embodiment of the present disclosure, the protection spring 53 is configured such that the protection pressure of the throttle orifice 541 of the protection valve is greater than the maximum opening pressure of the pilot valve portion 20. Since the protection spring 53 makes the protection pressure of the throttle orifice 541 of the protection valve greater than the maximum opening pressure of the pilot valve portion 20, it can be ensured that within the normal adjustment range of the pilot valve portion 20, the hydraulic oil pressure at the throttle orifice 541 of the protection valve will not reach the protection pressure, thereby ensuring that the pressure closed-loop proportional pressure valve of the present disclosure can control the pressure of the hydraulic oil at the main valve oil inlet 141 within an appropriate pressure range.

[0085] As Figure 1 shown, in an embodiment of the present disclosure, a connecting member 31 is provided in the pilot control oil circuit 30, and the connecting member 31 is respectively connected to the pilot valve throttle orifice 25, the protection valve throttle orifice 541, the main valve oil inlet 141, and the spring chamber 15. By providing the connecting member 31 in the pilot control oil circuit 30 and connecting the connecting member 31 to the pilot valve throttle orifice 25, the protection valve throttle orifice 541, the main valve oil inlet 141, and the spring chamber 15 respectively, it can be ensured that the pilot valve throttle orifice 25, the protection valve throttle orifice 541, the main valve oil inlet 141, and the spring chamber 15 are interconnected, thereby facilitating the pressure closed-loop proportional pressure valve of the present disclosure to achieve corresponding functions.

[0086] As Figure 1As shown, in an embodiment of the present disclosure, the main valve inlet 141 is provided at one axial end of the main valve spool 12, and the main valve outlet 142 is provided at the radial side of the main valve spool 12. Since the main valve inlet 141 is provided at one axial end of the main valve spool 12 and the main valve outlet 142 is provided at the radial side of the main valve spool 12, it can be ensured that after the main valve spool 12 of the present disclosure moves a small distance, it can move from the closed position to the open position, thereby greatly improving the response speed of the pressure closed-loop proportional pressure valve of the present disclosure.

[0087] The present disclosure also provides a hydraulic control system, including an oil inlet pipeline, an oil outlet pipeline, and the aforementioned pressure closed-loop proportional pressure valve. The oil inlet pipeline is communicated with the main valve inlet 141 of the pressure closed-loop proportional pressure valve, and the oil outlet pipeline is communicated with the main valve outlet 142 of the pressure closed-loop proportional pressure valve.

[0088] Compared with the existing hydraulic control system, the hydraulic control system of the present disclosure can use the pressure sensor 40 and the control unit to closed-loop control the real-time pressure of the oil inlet pipeline. The control pressure linearity, hysteresis, and control accuracy are greatly improved compared with the existing proportional pressure valve. The response speed is fast, and the dynamic characteristics are greatly improved. It can be applied to occasions with higher control accuracy requirements, especially can be widely applied to the automation control of various equipment such as metallurgy, power generation, petrochemical, intelligent manufacturing, machine tools, intelligent devices, energy transportation, engineering equipment, testing machines, etc.

[0089] The above has described the embodiments of the present disclosure. The above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations are obvious to those of ordinary skill in the art in the technical field without departing from the scope and spirit of the described embodiments. The choice of terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements to the technology in the market, or to enable other ordinary skilled persons in the technical field to understand the embodiments disclosed herein. The scope of the present disclosure is defined by the appended claims.

Claims

1. A proportional pressure valve with a pressure closed loop, characterized in that: include: A main valve portion (10), the main valve portion (10) comprising a main valve body (11), a main valve core (12) and a main valve return spring (13), the main valve core (12) forming a main valve cavity (14) and a spring cavity (15); the main valve cavity (14) and the spring cavity (15) are isolated from each other by the main valve core (12); The main valve cavity (14) is provided with a main valve oil inlet (141) and a main valve oil outlet (142), respectively. The main valve core (12) has an open position and a closed position. When in the open position, the main valve oil inlet (141) and the main valve oil outlet (142) are connected. When in the closed position, the main valve oil inlet (141) and the main valve oil outlet (142) are disconnected. The main valve return spring (13) is located in the spring cavity (15) and is configured to push the main valve core (12) in the direction of the closed position. The hydraulic oil in the main valve oil inlet (141) is configured to push the main valve core (12) in the direction of the open position, and the main valve oil inlet (141) is connected to the spring cavity (15) through a pilot control oil circuit (30). A pilot valve portion (20), the pilot valve portion (20) at least comprising a proportional solenoid (21), the proportional solenoid (21) being configured to control the opening pressure of the pilot valve portion (20) based on an input; the pilot valve portion (20) being configured to allow the hydraulic oil in the spring chamber (15) to leak out when the hydraulic oil pressure at the main valve oil inlet (141) is greater than the opening pressure of the pilot valve portion (20), so as to move the main valve core (12) to the opening position; a pressure sensor (40), the pressure sensor (40) being configured to obtain the real-time pressure of the hydraulic oil in the pilot control oil circuit (30); A control unit is configured to control the input of the proportional solenoid (21) based on the real-time pressure of the hydraulic oil in the pilot control oil circuit (30) obtained by the pressure sensor (40), so as to keep the real-time pressure of the hydraulic oil in the pilot control oil circuit (30) at a set pressure.

2. The proportional pressure valve with pressure closed loop according to claim 1, characterized in that: The pilot valve portion (20) at least further includes a pilot valve oil drain port (22), and the proportional solenoid (21) is configured to control the opening pressure of the pilot valve portion (20) based on an input; when the hydraulic oil pressure at the main valve oil inlet (141) is greater than the opening pressure of the pilot valve portion (20), the hydraulic oil in the spring chamber (15) is drained from the pilot valve oil drain port (22) to move the main valve core (12) to the open position.

3. The proportional pressure valve with pressure closed loop according to claim 2, characterized in that: The pilot valve portion (20) further comprises a pilot valve body (23) and a pilot valve core (24); a pilot valve cavity is formed in the pilot valve body (23), at least a pilot valve throttle port (25) is provided in the pilot valve cavity, and the pilot valve throttle port (25) is configured to communicate with the main valve oil inlet (141) through the pilot control oil circuit (30); The pilot valve core (24) has a pilot closing position and a pilot opening position, and the proportional solenoid (21) is configured to control the opening pressure of the pilot valve core (24) when switching from the pilot closing position to the pilot opening position; When the hydraulic oil pressure at the main valve oil inlet (141) does not reach the opening pressure, the pilot valve core (24) is in the pilot closing position, the pilot valve throttle (25) is closed, and the main valve core (12) is in the closing position; When the hydraulic oil pressure at the main valve oil inlet (141) reaches the opening pressure, the pilot valve core (24) switches to the pilot opening position, the pilot valve throttle port (25) opens, and at least part of the hydraulic oil in the spring chamber (15) flows out from the pilot valve throttle port (25) to the pilot valve oil drain port (22), and the main valve core (12) moves to the opening position, so that the main valve oil inlet (141) and the main valve oil outlet (142) are connected.

4. The proportional pressure valve with pressure closed loop according to claim 3, characterized in that: The pilot valve core (24) is constructed with a conical end and is fixedly connected to the output end of the proportional solenoid (21); The pilot valve body (23) comprises a pilot outer valve body (231) and a pilot inner valve body (232), the pilot inner valve body (232) and the pilot valve core (24) are both arranged in a pilot valve cavity inside the pilot outer valve body (231), and the pilot valve throttle (25) is formed on the pilot inner valve body (232); When the pilot valve core (24) is in the pilot closing position, the end of the pilot valve core (24) is inserted into the pilot valve throttle port (25) so that the pilot valve throttle port (25) is closed; when the pilot valve core (24) is in the pilot opening position, a throttling gap is formed between the end of the pilot valve core (24) and the pilot valve throttle port (25) so that the pilot valve throttle port (25) is opened.

5. The proportional pressure valve with pressure closed loop according to claim 4, characterized in that: Also includes a protective valve portion (50); The protection valve portion (50) comprises a protection valve body (51), a protection valve core (52) and a protection spring (53); a protection valve cavity (54) is formed in the protection valve core (52), and at least a protection valve throttle port (541) and a protection valve oil drain port (542) are provided in the protection valve cavity (54); the protection valve throttle port (541) is configured to communicate with the main valve oil inlet (141) through the pilot control oil circuit (30), one end of the protection valve core (52) is in contact with the protection spring (53), and the other end is matched with the protection valve throttle port (541); When the hydraulic oil pressure at the protection valve throttle port (541) does not reach the protection pressure, the protection valve core (52) closes the protection valve throttle port (541); When the hydraulic oil pressure at the protection valve throttle port (541) reaches the protection pressure, the hydraulic oil in the pilot control oil circuit (30) overcomes the elastic force of the protection spring (53) and pushes the protection valve core (52) to move, so that the protection valve throttle port (541) is opened, and at least part of the hydraulic oil in the pilot control oil circuit (30) flows out from the protection valve throttle port (541) to the protection valve oil drain port (542).

6. The proportional pressure valve with pressure closed loop according to claim 5, characterized in that: The protection spring (53) is configured to make the protection pressure of the protection valve throttle (541) greater than the maximum opening pressure of the pilot valve portion (20).

7. The proportional pressure valve with pressure closed loop according to claim 5, characterized in that: A connecting piece (31) is provided in the pilot control oil circuit (30), and the connecting piece (31) is respectively connected to the pilot valve throttle port (25), the protection valve throttle port (541), the main valve oil inlet port (141) and the spring chamber (15).

8. The proportional pressure valve with pressure closed loop according to any one of claims 1 to 7, characterized in that: The main valve oil inlet (141) is arranged at one axial end of the main valve core (12), and the main valve oil outlet (142) is arranged at a radial side of the main valve core (12).

9. The proportional pressure valve with pressure closed loop according to any one of claims 1 to 7, characterized in that: The proportional solenoid (21) is configured to control the opening pressure of the pilot valve portion (20) based on an input current; The control unit is configured to control the input current of the proportional solenoid (21) based on the real-time pressure of the hydraulic oil in the pilot control oil circuit (30) acquired by the pressure sensor (40), so as to keep the real-time pressure of the hydraulic oil in the pilot control oil circuit (30) at a set pressure.

10. A hydraulic control system, characterized in that: It comprises an oil inlet pipeline, an oil outlet pipeline and a pressure closed-loop proportional pressure valve as claimed in any one of claims 1 to 9, wherein the oil inlet pipeline is connected to the main valve oil inlet (141) of the pressure closed-loop proportional pressure valve, and the oil outlet pipeline is connected to the main valve oil outlet (142) of the pressure closed-loop proportional pressure valve.

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