Two-stage overflow hydraulic control device and hydraulic system

Abstract

The application belongs to the technical field of hydraulic pressure, and particularly relates to a two-stage overflow hydraulic control device and a hydraulic system. The hydraulic control system comprises a shell, a three-position four-way reversing valve and a valve group. The valve group is connected with at least one of the third interface and the fourth interface of the three-position four-way reversing valve, and is connected with the inlet and the outlet to adjust the overflow pressure of the hydraulic system. The application only needs to cooperate the single reversing valve with the main overflow unit, and the reversing valve can realize the system unloading, the high-low pressure two-stage overflow pressure control in different positions. The application not only constructs the internal control logic closed loop, realizes the stable pressure regulation and the large-flow non-impact unloading, but also greatly simplifies the structure of the multi-stage pressure regulation circuit, greatly improves the functional integration degree and reduces the system cost and the failure rate.

Description

Technical Field

[0001] This invention belongs to the field of hydraulic technology, and particularly relates to a two-stage overflow hydraulic control device and hydraulic system. Background Technology

[0002] In various hydraulic systems, different system safety overflow pressures are often required depending on the different working devices, operating conditions, or load differences of the actuators. For example, when harvesting machinery changes to different headers, construction machinery switches between different attachments, and special vehicles perform different actions, different requirements are placed on the system overflow pressure.

[0003] Existing technologies typically require a separate relief valve of the corresponding pressure rating for each working device, resulting in poor versatility. When changing working mechanisms, the relief valve must be replaced simultaneously, leading to cumbersome disassembly and assembly procedures and low operational efficiency. The large variety of parts and high management costs, along with multiple specifications of relief valves, increase the burden on production, inventory, and after-sales maintenance. Manual replacement of pressure regulating components is prone to problems such as improper pressure settings and non-standard installation. These issues can range from affecting operational reliability to causing damage to hydraulic components or overloading of transmission parts due to excessive pressure, posing serious safety hazards. Summary of the Invention

[0004] The present invention aims to at least partially solve one of the technical problems in the related art.

[0005] This invention provides a two-stage overflow hydraulic control device for a hydraulic system, comprising: A housing having an inlet and an outlet; A three-position four-way directional valve, the three-position four-way directional valve having a first port, a second port, a third port and a fourth port, wherein one of the first port and the second port is connected to the inlet and the other is connected to the outlet; A valve assembly, connected to at least one of the third and fourth interfaces, and connected to both the inlet and the outlet, for regulating the overflow pressure of the hydraulic system.

[0006] The two-stage overflow hydraulic control device of the present invention includes a housing with an inlet and an outlet, a three-position four-way directional valve, and a valve assembly. By adjusting the connection relationship between the first, second, third, and fourth ports, and in conjunction with the valve assembly, the overflow pressure of the hydraulic system is adjusted to achieve two-stage overflow. This facilitates the matching and switching of overflow pressure for different working mechanisms, eliminating the need to replace different overflow components for different working mechanisms, reducing cumbersome disassembly and assembly, and improving versatility and reliability. The overflow pressure of the three-position four-way directional valve differs between its left and right positions to achieve different overflow pressures. When the three-position four-way directional valve is in the neutral position, the working pump returns to the oil tank through the directional valve, which can be used for system startup, shutdown, or when the working mechanism is not in operation, reducing impact and energy consumption.

[0007] In some embodiments, the valve assembly includes two valve structures.

[0008] The overflow pressure of the hydraulic system can be adjusted by setting only two valves, which is simple in structure.

[0009] In some embodiments, the valve assembly includes a first valve and a second valve having a different pressure rating than the first valve. The housing has a first supply flow path and a first return flow path. The inlet is connected to one end of the first valve and a second interface through the first supply flow path, and the outlet is connected to the first interface and the other end of the first valve through the first return flow path.

[0010] When the system's overflow level needs to be set to the first overflow level, connect the first port to the fourth port and the second port to the third port. At this time, the system's overflow level is the same as the overflow level of the first valve. When the system's overflow level needs to be set to the second overflow level, connect the first port to the third port and the second port to the fourth port. At this time, the system's overflow level is the same as the overflow level of the second valve. The structure is simple, the operation is convenient, and the reliability is high.

[0011] In some embodiments, the first valve has a fifth port and a sixth port, the fifth port being connected to the inlet via the first liquid supply path, and the sixth port being connected to the outlet via the first liquid return path.

[0012] When the system overflow level is set to the first overflow level, when the system pressure is greater than the first overflow level, the hydraulic oil will overcome the spring force of the first valve, flow into the first valve from the fifth port, and then flow out from the sixth port back to the oil tank. The structure is simple, the operation is convenient, and the reliability is high.

[0013] In some embodiments, the second valve has a seventh port and an eighth port, the seventh port being connected to the fourth port, and the eighth port being connected to the outlet via a first return flow path.

[0014] When the system overflow level is set to the second overflow level, when the system pressure is greater than the second overflow level, the hydraulic oil will overcome the spring force of the second valve, flow into the second valve from the seventh port, and then flow out from the eighth port back to the oil tank. The structure is simple, the operation is convenient, and the reliability is high.

[0015] In some embodiments, the valve assembly includes a third valve and a fourth valve, the third interface is connected to the third valve, the fourth interface is connected to the fourth valve, the third valve is connected to both the inlet and the outlet, and the fourth valve is connected to both the inlet and the outlet.

[0016] When the system's overflow level needs to be set to the first overflow level, connect the first interface to the fourth interface, and connect the second interface to the third interface. When the system's overflow level needs to be set to the second overflow level, connect the first interface to the third interface, and connect the first interface to the fourth interface. The structure is simple, the operation is convenient, and the reliability is high.

[0017] In some embodiments, the housing is provided with a first control flow path and a second control flow path, the inlet is connected to the first interface through the first control flow path, and the radial dimension of the first control flow path gradually increases at least partially from the inlet to the first interface, and the second interface is connected to the outlet through the second control flow path.

[0018] When unloading is required, the three-position four-way directional valve is in the neutral position, the second port is connected to the fourth port, and the fourth valve is opened so that the liquid output from the working pump flows back to the oil tank through the fourth valve. The structure is simple and the operation is convenient.

[0019] In some embodiments, the housing is provided with a third control flow path and a first main flow path. The third valve has a ninth interface, a tenth interface, and an eleventh interface. The ninth interface is connected to the third interface through the third control flow path. The inlet is connected to the tenth interface through the first main flow path, and the outlet is connected to the eleventh interface through a second main flow path. The third valve is a pilot-operated relief valve with a pilot hydraulic control chamber connected to the third interface through the ninth interface and the third control flow path. When the system's overflow level is set to the first overflow level, when the system pressure exceeds the first overflow level, the hydraulic oil only needs to overcome the spring force of the third valve's overflow valve core. The hydraulic oil enters the first valve through the tenth interface via the first main flow path, then flows out of the first valve through the eleventh interface, and flows back to the oil tank from the outlet via the second main flow path. This design is simple in structure, convenient in operation, and highly reliable.

[0020] In some embodiments, the housing is provided with a fourth control flow path and a fourth main flow path, the fourth valve has a twelfth interface, a thirteenth interface and a fourteenth interface, the twelfth interface is connected to the fourth interface through the fourth control flow path, the thirteenth interface is connected to the inlet through the fourth main flow path, and the fourteenth interface is connected to the outlet through the fifth main flow path.

[0021] When the system overflow level is set to the second overflow level, the control oil enters the third and fourth valves. The hydraulic oil overcomes the spring force of the third valve and the control oil. The hydraulic oil enters the first valve through the tenth interface via the first main flow path, and then flows out of the first valve through the eleventh interface. It then flows back to the oil tank from the outlet via the second main flow path. The structure is simple, the operation is convenient, and the reliability is high.

[0022] The present invention also provides a hydraulic system including the above-described two-stage overflow hydraulic control device.

[0023] The hydraulic system of the present invention, by setting a three-position four-way directional valve and valve group, can adjust the overflow pressure of the hydraulic system to achieve two-stage overflow, which facilitates the matching and switching of overflow pressure for different working mechanisms, eliminating the need to install different overflow components for different working structures, and improving the versatility and reliability of the hydraulic system. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the structure of a two-stage overflow hydraulic control device provided in one embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of a two-stage overflow hydraulic control device provided in another embodiment of the present invention.

[0026] Figure 3 This is a schematic diagram of the structure of the third valve in a two-stage overflow hydraulic control device provided in another embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the fourth valve in a two-stage overflow hydraulic control device provided in another embodiment of the present invention.

[0027] Figure label: 1. Housing; 11. Inlet; 12. Outlet; 13. Pilot spring mounting cavity; 14. Pilot hydraulic control cavity; 15. Damping flow path; 16. Overflow return flow path; 17. Main cavity; 18. First cavity; 181. Unloading control cavity; 182. Connecting cavity; 2. Three-position four-way directional valve; 21. First port; 22. Second port; 23. Third port; 24. Fourth port; 3. Valve assembly; 31. First valve; 311. Fifth port; 312. Sixth port; 32. Second valve; 321. Seventh port; 322. Eighth port; 33. Third valve; 331. Ninth port; 332. Tenth port; 333. Eleventh port; 334. Overflow valve core; 335. Main spring; 336. Pilot spring; 337. Pilot valve core; 34. Fourth valve; 341. Twelfth port; 342. Thirteenth port; 343. Fourteenth port; 344. Unloading valve core; 345. Unloading spring; 4. First control flow path; 5. Second control flow path; 6. Third control flow path; 7. First main flow path; 8. Second main flow path; 9. Fourth control flow path; 10. Fourth main flow path; 20. Fifth main flow path; 30. Working pump; 40. Engine; 50. Oil tank; 60. First supply flow path; 70. First return flow path. Detailed Implementation

[0028] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be particularly noted that the following embodiments are for illustrative purposes only and do not limit the scope of the application. Similarly, the following embodiments are only some, not all, embodiments of the present application, and all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of the present application.

[0029] The terms "first," "second," and "third" used in the embodiments of this application are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first," "second," or "third" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. All directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationships and movement of components in a specific posture (as shown in the figures). If the specific posture changes, the directional indication will also change accordingly. The terms "comprising" and "having," and any variations thereof, in the embodiments of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or components inherent to these processes, methods, products, or devices.

[0030] like Figure 1 and Figure 2 As shown, a two-stage relief hydraulic control device is used in a hydraulic system. The two-stage relief hydraulic control device includes a housing 1, a three-position four-way directional valve 2, and a valve assembly 3. The housing 1 has an inlet 11 and an outlet 12. The three-position four-way directional valve 2 has a first port 21, a second port 22, a third port 23, and a fourth port 24. One of the first port 21 and the second port 22 is connected to the inlet 11, and the other is connected to the outlet 12. The valve assembly 3 is connected to at least one of the third port 23 and the fourth port 24, and is also connected to both the inlet 11 and the outlet 12 to regulate the relief pressure of the hydraulic system.

[0031] This embodiment of the two-stage overflow hydraulic control device includes a housing 1 with an inlet 11 and an outlet 12, a three-position four-way directional valve 2, and a valve assembly 3. By adjusting the connection between the first port 21, the second port 22, the third port 23, and the fourth port 24, the valve assembly 3 is used to regulate the overflow pressure of the hydraulic system, achieving two-stage overflow with different overflow pressures. By matching and switching the overflow pressure for different working mechanisms, it eliminates the need to install different overflow components for different working structures, improving the versatility and reliability of the hydraulic system. It also avoids the problems of improper pressure setting and non-standard installation that can easily occur when manually replacing overflow devices for different working mechanisms. This avoids problems such as affecting operational reliability or, more seriously, damaging hydraulic components or overloading transmission parts due to excessive pressure caused by improper installation or improper pressure setting. The three-position four-way directional valve 2 and the valve assembly 3 can be installed on or inside the housing to improve integration, reduce size, and improve stability by integrating them into the housing to avoid external impacts.

[0032] In some embodiments, valve assembly 3 includes two valve structures.

[0033] The overflow pressure of the hydraulic system can be adjusted by setting only two valves, which is simple in structure.

[0034] The following is Example 1: like Figure 1 As shown, in some embodiments, valve assembly 3 includes a first valve 31 and a second valve 32 with a different pressure rating than the first valve 31. The housing 1 has a first supply flow path 60 and a first return flow path 70. The inlet 11 is connected to one end of the first valve 31 and a second interface 22 via the first supply flow path 60, and the outlet 12 is connected to the other end of the first interface 21 and the first valve 31 via the first return flow path 70. When the system overflow rating needs to be set to the first overflow rating, the first interface 21 is connected to the fourth interface 24, and the second interface 22 is connected to the third interface 23. At this time, the system overflow rating is the same as the overflow rating of the first valve 31. When the system overflow rating needs to be set to the second overflow rating, the first interface 21 is connected to the third interface 23, and the second interface 22 is connected to the fourth interface 24. At this time, the system overflow rating is the same as the overflow rating of the second valve 32. The structure is simple, the operation is convenient, and the reliability is high. In some embodiments, the first valve 31 has a fifth port 311 and a sixth port 312. The fifth port 311 is connected to the inlet 11, and the sixth port 312 is connected to the outlet 12. When the system overflow level is set to the first overflow level, when the system pressure is greater than the first overflow level, the hydraulic oil will overcome the spring force of the first valve 31, flow into the first valve 31 from the fifth port 311, and then flow out from the sixth port 312 back to the oil tank 50. The structure is simple, the operation is convenient, and the reliability is high.

[0035] In some embodiments, the second valve 32 has a seventh port 321 and an eighth port 322. The seventh port 321 is connected to one of the third port 23 and the fourth port 24, and the eighth port 322 is connected to the outlet 12. When the system overflow level is set to the second overflow level, when the system pressure is greater than the second overflow level, the hydraulic oil will overcome the spring force of the second valve 32, flow into the second valve 32 from the seventh port 321, and then flow out from the eighth port 322 back to the oil tank 50. The structure is simple, the operation is convenient, and the reliability is high.

[0036] It is understood that both the three-position four-way directional valve 2 and the valve assembly 3 are located inside or on the housing 1. The housing 1 contains a first supply flow path 60 and a first return flow path 70. The inlet of the first supply flow path 60 is connected to the inlet 11 of the housing 1, and the outlet of the first supply flow path 60 is connected to the first interface 21 and the fifth interface 311, respectively. The inlet of the first return flow path 70 is connected to the eighth interface 322 and the sixth interface 312, respectively. The fifth port 311 can be understood as the inlet of the first valve 31, and the sixth port 312 can be understood as the outlet of the first valve 31, or a pressure relief port. The seventh port 321 can be understood as the inlet of the second valve 32, and the eighth port 322 can be understood as the outlet of the second valve 32, or a pressure relief port.

[0037] Liquid enters the first valve 31 from the fifth port 311. When the liquid in the first supply flow path 60 reaches or exceeds the overflow pressure of the first valve 31, the liquid flows out from the sixth port 312 of the first valve 31 and enters the first return flow path 70, and then flows back to the oil tank 50.

[0038] Liquid enters the second valve 32 from the seventh port 321. When the liquid in the first supply flow path 60 reaches or exceeds the overflow pressure of the second valve 32, the liquid flows out from the eighth port 322 of the second valve 32 and enters the first return flow path 70, and then flows back to the oil tank 50.

[0039] In some embodiments, the two-stage overflow hydraulic control device further includes a working pump 30, an engine 40, and an oil tank 50. The working pump 30 is driven by the engine 40.

[0040] like Figure 1 As shown, the working principle is as follows: When the three-position four-way directional valve 2 is in the left position, the first port 21 and the fourth port 24 are connected, the second port 22 and the third port 23 are connected, and the third port 23 is closed. When the three-position four-way directional valve 2 is in the left position, pressurized oil flows in from the inlet 11, passes through the first valve 31, and then flows out from the outlet 12. Pressurized oil cannot enter the second valve 32. At this time, the system's overflow level is determined by the overflow level of the first valve 31. When the three-position four-way directional valve 2 is in the neutral position, the first port 21 and the second port 22 are connected, and pressurized oil flows in from the inlet 11, passes through the first port 21 and the second port 22, and then flows out from the outlet 12, achieving the system unloading function. When the three-position four-way directional valve 2 is in the right position, the first port 21 and the third port 23 are connected, and the second port 22 and the fourth port 24 are connected. Pressurized oil flows in from the inlet 11, passes through the second port 22 and the fourth port 24, and then flows into the second valve 32. At this point, the overflow level of the system is determined by the overflow level of the second valve 32.

[0041] Specifically, when the system's overflow level needs to be set to the overflow level of the first valve 31, the three-position four-way directional valve 2 is controlled to be in the left position. At this time, if the pressure of the oil in the system is greater than the overflow level of the first valve 31, the oil flows in from the inlet 11. The oil can overcome the spring force of the first valve 31 and open its valve port. The oil then flows into the first valve 31 from the fifth port 311, and then flows out of the first valve 31 from the sixth port 312, flowing to the outlet 12. At this time, the system's overflow level is the overflow level of the first valve 31. When unloading is required, the three-position four-way directional valve 2 is controlled to be in the neutral position. At this time, the oil flows from the inlet 11 to the first port 21, enters the three-position four-way directional valve 2, and then flows out of the three-position four-way directional valve 2 from the second port 22, flowing to the outlet 12, thus realizing the system unloading function. When the overflow level of the system needs to be set to the overflow level of the second valve 32, the three-position four-way directional valve 2 is controlled to be in the right position. At this time, if the pressure of the oil in the system is greater than the overflow level of the second valve 32, the oil can overcome the spring force of the second valve 32 and open the valve port of the second valve 32. The oil flows into the second valve 32 from the seventh port 321 and then flows to the outlet 12 from the eighth port 322.

[0042] For example, the overflow level of the first valve 31 is 10 MPa, and the overflow level of the second valve 32 is 20 MPa. When the overflow level of the system needs to be set to 10 MPa, the three-position four-way directional valve 2 is controlled to the left position. At this time, if the pressure oil in the system is greater than 10 MPa, the pressure oil will overcome the spring force of the first valve 31, opening the valve port of the first valve 31. After passing through the first valve 31, it flows to the outlet 12 and back to the oil tank 50, ensuring that the pressure oil in the system is always maintained at 10 MPa. When the overflow level of the system needs to be set to 20 MPa, the three-position four-way directional valve 2 is controlled to the right position. At this time, if the pressure oil in the system is greater than 20 MPa, the pressure oil will overcome the spring force of the second valve 32, opening the valve port of the second valve 32. After passing through the second valve 32, it flows to the outlet 12 and back to the oil tank 50, ensuring that the pressure oil in the system is always maintained at 20 MPa.

[0043] It should be noted that both the first valve 31 and the second valve 32 can be existing direct-acting relief valves, and their relief pressure depends on the set pressure of the spring of the corresponding first valve 31 or second valve 32. In this embodiment 1, the set pressure of the spring of the second valve 32 is greater than the set pressure of the spring of the first valve 31.

[0044] The effect of this embodiment 1 is as follows: By cooperating with the three-position four-way directional valve 2 and two relief valves with fixed pressure levels, the goal of freely switching between two relief levels can be achieved without replacing any relief components. When the three-position four-way directional valve 2 is in the left position, primary relief (low-pressure relief) is achieved through the first valve 31. When the three-position four-way directional valve 2 is in the middle position, the first port 21 and the second port 22 of the three-position four-way directional valve 2 are connected. The pressure oil output from the working pump 30 flows in from the inlet 11, flows out from the outlet 12 through the first port 21 and the second port 22, and achieves the high-flow unloading function of the system. When the three-position four-way directional valve 2 is in the right position, pressure oil flows in from the inlet 11, flows into the second valve 32 through the second port 22 and the fourth port 24. At this time, the relief level of the system is determined by the relief level of the second valve 32, and secondary relief (high-pressure relief) is achieved through the second valve 32. This eliminates the need to replace and install different relief components when changing the hydraulic mechanism, reducing safety or stability problems caused by improper manual installation or unreasonable pressure settings. By cooperating with a three-position four-way directional valve 2 and two relief valves with fixed pressure ratings, the system achieves two-stage relief pressure control at low and high pressure levels, enabling smooth pressure regulation and shock-free unloading. This eliminates the need for excessive relief components, reducing the size of the relief device. It solves the problems of complex structure, large pressure switching shocks, and poor energy efficiency associated with traditional multi-stage pressure regulating circuits. Furthermore, it eliminates the need for electrical control or pressure sensors. The hydraulic system of this invention features a self-contained closed-loop control logic, stable pressure regulation, high functional integration, and rapid response, reducing costs and potential failure points.

[0045] Meanwhile, both the first fluid supply path 60 and the first fluid return path 70 are cast or machined channels inside the housing 1. The connection between the three-position four-way directional valve 2 and the two relief valves does not require any external hoses or detachable joints, eliminating the physical hazards of external pipelines loosening or fatigue fracture under high-frequency vibration. At the same time, in working environments with external dust, humidity, or drastic temperature changes, it isolates the possibility of metal shavings and moisture in the air entering the hydraulic system, improves the stability of the two-stage relief hydraulic control device, reduces the number and types of relief components used, and lowers the size and cost of the two-stage relief hydraulic control device.

[0046] The following is Example 2: like Figure 2 As shown, in some embodiments, valve group 3 includes a third valve 33 and a fourth valve 34 disposed within or on housing 1. Third port 23 is connected to third valve 33, and fourth port 24 is connected to fourth valve 34. Third valve 33 is connected to both inlet 11 and outlet 12, and fourth valve 34 is connected to both inlet 11 and outlet 12. When the system overflow level needs to be set to the first overflow level, the three-position four-way directional valve 2 is in the left position, connecting first port 21 to fourth port 24, and connecting second port 22 to third port 23. When the system overflow level needs to be set to the second overflow level, the three-position four-way directional valve 2 is in the right position, connecting first port 21 to third port 23, and connecting first port 21 to fourth port 24. The structure is simple, operation is convenient, and reliability is high.

[0047] In some embodiments, inlet 11 is connected to first interface 21 via first control flow path 4. The radial dimension, or flow area, of first control flow path 4 gradually increases from inlet 11 to first interface 21. Second interface 22 is connected to outlet 12 via second control flow path 5. When unloading is required, three-position four-way directional valve 2 is in the neutral position, and fourth interface 24 is connected to second interface 22. Control oil enters three-position four-way directional valve 2 from first interface 21 and then flows into third valve 33 from third interface 23. Fourth interface 24 is connected to fourth valve 34, thereby opening fourth valve 34. Liquid output from working pump 30 flows back to oil tank 50 through the opening of fourth valve 34. The structure is simple and the operation is convenient.

[0048] In some embodiments, the third valve 33 has a ninth port 331, a tenth port 332, and an eleventh port 333. The ninth port 331 is connected to the third port 23 through the third control flow path 6. The inlet 11 is connected to the tenth port 332 through the first main flow path 7, and the outlet 12 is connected to the outlet 12 through the third main flow path. When the system overflow level is set to the first overflow level, when the system pressure is greater than the first overflow level, the hydraulic oil overcomes the spring force of the third valve 33. The hydraulic oil enters the first valve 31 through the first main flow path 7 via the tenth port 332, and then flows out of the first valve 31 through the eleventh port 333. It then flows back to the oil tank 50 through the second main flow path 8 from the outlet 12. The structure is simple, the operation is convenient, and the reliability is high.

[0049] In some embodiments, the fourth valve 34 has a twelfth port 341, a thirteenth port 342, and a fourteenth port 343. The twelfth port 341 is connected to the fourth port 24 via the fourth control flow path 9, the thirteenth port 342 is connected to the inlet 11 via the fourth main flow path 10, and the fourteenth port 343 is connected to the outlet 12 via the fifth main flow path 20. When the system overflow level is set to the second overflow level, control oil enters the third valve 33 and the fourth valve 34. The hydraulic oil overcomes the spring force of the third valve 33 and the control oil, and flows through the first main flow path 7, through the tenth port 332, into the first valve 31, and then flows out of the first valve 31 through the eleventh port 333. It then flows back to the oil tank 50 from the outlet 12 via the second main flow path 8. The structure is simple, the operation is convenient, and the reliability is high.

[0050] like Figure 3 As shown, the third valve 33 is a conventional pilot-operated relief valve. The structure of the pilot-operated relief valve includes a relief valve core 334, a main spring 335, a pilot spring 336, a pilot valve core 337, and a pilot spring mounting cavity 13, a pilot hydraulic control cavity 14, a damping flow path 15, an overflow return flow path 16, and a main cavity 17 provided in the housing 1. like Figure 3As shown, the bottom of the main cavity 17 is connected to the tenth interface 332, the middle of the main cavity 17 is connected to the eleventh interface 333, and the top of the main cavity 17 is connected to the pilot hydraulic control cavity 14. The overflow valve core 334 is movably disposed in the main cavity 17. One end of the main spring 335 abuts against the end of the main cavity 17 away from the tenth interface 332, and the other end of the main spring 335 is connected to the overflow valve core 334. The pilot hydraulic control cavity 14 is connected to the first control flow path 4, and the other end of the pilot hydraulic control cavity 14 is installed with the pilot spring. The pilot spring mounting cavity 13 is connected to the overflow return flow path 16 through a damping circuit. The pilot spring 336 and the pilot valve core 337 are installed in the pilot spring mounting cavity 13. One end of the pilot spring 336 abuts against the pilot spring mounting cavity 13, and the other end of the pilot spring 336 abuts against the pilot valve core 337. The pilot spring 336 extends and retracts to move the pilot valve core 337 so that the pilot valve core 337 closes or opens the connection between the pilot hydraulic control cavity 14 and the pilot spring mounting cavity 13.

[0051] When the three-position four-way directional valve 2 is in the right position, the first port 21 and the third port 23 are connected. The liquid output from the working pump 30 is output to the third port 23 through the first control flow path 4 and the first port 21. Then the liquid is delivered to the pilot hydraulic control chamber 14. When the liquid pressure reaches the preset pressure of the pilot spring 336, the pilot spring 336 contracts to connect the pilot hydraulic control chamber 14 with the pilot spring mounting chamber 13. At this time, the liquid enters the damping flow path 15 through the pilot hydraulic control chamber 14 and then enters the overflow return flow path 16. Since at least part of the radial dimension or flow area of ​​the first control flow path 4 extends from the inlet 11 of the housing 1 to the first... The direction of interface 21 gradually increases or expands to achieve a similar effect to a damping orifice. When the liquid flows in the pilot hydraulic control chamber 14, the bottom of the overflow valve core 334 is subjected to a constant liquid pressure from the tenth interface 332. Affected by the first control flow path 4, the top of the overflow valve core 334 is subjected to a decrease in liquid pressure from the pilot hydraulic control chamber 14. At this time, the overflow pressure of the third valve 33 is the sum of the set pressure of the overflow valve core spring (i.e., the main spring 335) and the pressure exerted on the top of the overflow valve core 334 by the liquid pressure of the pilot hydraulic control chamber 14. At this time, the third valve 33 can achieve a relatively high pressure overflow, i.e., high pressure overflow.

[0052] When the three-position four-way directional valve 2 is in the left position, the third port 23 is connected to the second port 22. Since the second port 22 is connected to the oil tank, the pilot hydraulic control chamber 14 is connected to the oil tank 50 through the second control flow path 5. At this time, the overflow pressure of the third valve 33 is only the set pressure of the main spring 335. This pressure is less than the sum of the pressure of the main spring 335 of the overflow valve and the liquid pressure of the pilot hydraulic control chamber 14. That is, at this time, the third valve 33 can achieve a relatively low pressure overflow, i.e., low pressure overflow.

[0053] Embodiment 2 of this invention achieves a high degree of integration and ingenious coordination by incorporating a three-position four-way directional valve 2, a relief valve (third valve 33), and a unloading valve (fourth valve 33) into a single valve body, thus replacing the traditional, cumbersome multi-stage pressure regulating valve assembly. The entire system achieves low-pressure unloading and multi-stage high-pressure control while simplifying the piping structure, reducing the number of hydraulic components, improving the system's functional integration, lowering the overall manufacturing and assembly costs, and reducing potential hydraulic failure points at the source. It also avoids the need to simultaneously replace the relief valve when changing different working devices. Manual operation has low conversion efficiency, and setting different hydraulic relief devices for multiple hydraulic components results in a large variety of parts, high management costs, and manual replacement affects operational reliability and poses serious safety hazards. This invention uses only a three-position four-way directional valve 2 in conjunction with the third valve 33 and the fourth valve 33 to achieve a two-stage pressure regulation scheme. It can simultaneously realize three modes: mid-position unloading, low-pressure operation, and high-pressure operation, without the need for an additional unloading valve, and the functions are highly integrated. When the directional valve changes position, the on / off of the cartridge valve and the pressure regulation of the relief valve are completed synchronously. The hydraulic system has its own internal control logic closed loop, stable pressure regulation, no lag, and small impact, resulting in smoother system operation. It has a wide range of applications, relying on the large flow capacity of the cartridge valve to accommodate large flow systems, and can achieve two-stage pressure without modifying the relief valve body. It has fewer components, simpler piping, energy saving, and lower cost.

[0054] A pure hydraulic control internal control feedback logic closed loop is constructed through the first control flow path 4 (with at least a partial diameter change in flow area), the three-position four-way directional valve 2, and the third valve 33 and the fourth valve 34. The pressure regulation process relies entirely on the autonomous transmission of hydraulic signals within the system, without the need for complex external electrical control feedback. This results in extremely rapid system response, smooth pressure switching transitions, and stable and reliable regulation. Simultaneously, it solves the problems of complex structures, large pressure switching shocks, and poor energy efficiency inherent in traditional multi-stage pressure regulating circuits. The hydraulic system of this invention features a self-contained internal control logic closed loop, stable pressure regulation, high functional integration, rapid response, and reduced costs and potential failure points.

[0055] like Figure 4As shown, the fourth valve 34 is an unloading valve. The structure of the unloading valve includes a first chamber 18, an unloading valve core 344, and an unloading spring 345. The unloading valve core 344 is disposed in the first chamber 18 to divide the first chamber 18 into an unloading control chamber 181 and a flow chamber 182. The bottom of the flow chamber 182 is connected to the thirteenth interface 342, and the side of the flow chamber is connected to the fourteenth interface 343. One end of the unloading spring 345 abuts against the inner wall of the first chamber 18, and the other end of the unloading spring 345 abuts against the unloading valve core 344. The unloading valve core 344 moves to connect or disconnect the thirteenth interface 342 and the fourteenth interface 343, and the unloading control chamber 181 is connected to the twelfth interface 341. The flow chamber is a variable-diameter chamber, meaning its radial dimension gradually decreases away from the unloading control chamber 181. When the unloading spring 345 contracts, the unloading valve core 344 no longer contacts the inner wall of the flow chamber 182, thus connecting the thirteenth port 342 and the fourteenth port 343. At this time, the fourth valve 34 is in the open state. After unloading is completed, when the thirteenth port 342 no longer receives liquid output from the working pump 30, the unloading valve core 344 moves under the action of the unloading spring 345 to contact the inner wall of the connecting chamber 182, thereby disconnecting the thirteenth port 342 and the fourteenth port 343. Alternatively, the first interface 21 is connected to the fourth interface 24. That is, when the unloading control chamber 181 of the fourth valve 34 is supplied with liquid input from the working pump 30, the unloading valve core 344 is subjected to liquid pressure from the unloading control chamber 181 and liquid pressure from the connecting chamber 182. At this time, under the action of the unloading spring 345, the unloading valve core 344 moves to contact the inner wall of the connecting chamber 182, so as to disconnect the thirteenth interface 342 and the fourteenth interface 343.

[0056] When the fourth interface 24 is connected to the second interface 22, the unloading control chamber 181 is connected to the oil tank through the second control flow path. At this time, there is no liquid pressure in the unloading control chamber 181. The liquid output by the working pump 30 is output to the connecting chamber 182 through the fourth main flow path 10 and the thirteenth interface 342. The unloading valve core 344 is moved away from the connecting chamber 182 by the liquid pressure from the connecting chamber 182 so that the thirteenth interface 342 is connected to the fourteenth interface 343. The liquid output by the working pump 30 flows back to the oil tank 50 through the fourth main flow path 10, the thirteenth interface 342, the fourteenth interface 343 and the fifth main flow path 20. At this time, the unloading valve, i.e. the fourth valve 34, is in the open state, realizing pressureless unloading. The working pump 30 runs unloaded and can be used for system start-up, shutdown, or non-working state of the working structure, reducing impact and energy consumption. It can be understood that the set pressure of the unloading spring 345 is small and is only used for the reset of the unloading valve core 344, thereby realizing stable pressure regulation and large flow unloading without impact.

[0057] When the three-position four-way directional valve 2 switches to the neutral position, the pressure reduction and unloading characteristics of the pilot oil circuit (i.e., the fourth control flow path 4) are utilized to guide the main circuit (the fourth main flow path 10 and the fifth main flow path 20) through the large-diameter cartridge valve, or unloading valve (i.e., the fourth valve 33), to achieve shock-free unloading. This achieves true low-resistance, shock-free, and pressure-free unloading, allowing the working pump 30 to operate under no-load conditions when not in operation. This significantly reduces transient hydraulic shocks during system flow interruption or reversal, extends component life, and provides excellent energy-saving and emission-reduction effects.

[0058] When the fourth port 24 is connected to the first port 21, the liquid output by the working pump is output to the unloading control chamber 181 of the unloading valve, i.e. the fourth valve 34, through the first control flow path 4, the first port 21 and the fourth port 24. At this time, since the liquid pressure output by the unloading control chamber 181 at the top of the unloading valve core 344 is equal to the liquid pressure input by the thirteenth port 342 at the bottom, the unloading valve core 344 moves under the action of the unloading spring 345 to contact the inner wall of the connecting chamber 182, so as to realize the disconnection of the thirteenth port 342 and the fourteenth port 343. At this time, the unloading valve, i.e. the fourth valve 34, is in the closed state.

[0059] It should be noted that the flow areas of the first control flow path 4, the second control flow path 5, the third control flow path 6, and the fourth main flow path 10 are all smaller than the flow areas of the first main flow path 7, the second main flow path 8, the fourth main flow path 10, and the fifth main flow path 20.

[0060] like Figures 2 to 4 As shown, the working principle is as follows: When the three-position four-way directional valve 2 is in the left position, the first port 21 of the three-position four-way directional valve 2 is connected to the fourth port 24, and the second port 22 is connected to the third port 23. When the three-position four-way directional valve 2 is in the left position, control oil enters through inlet 11, passes through the three-position four-way directional valve 2, and enters the fourth valve 34, closing the fourth valve 34. The pressurized oil flows through the third valve 33 to outlet 12 and then back to the oil tank 50. At this time, the system overflow pressure is the set pressure of the main spring 335 of the third valve 33, and the overflow pressure is relatively low, i.e., low-pressure overflow, and the system overflow level is level one. When the three-position four-way directional valve 2 is in the middle position, the first port 21 of the three-position four-way directional valve 2 is connected to the third port 23, and the fourth port 24 is connected to the second port 22. The pressurized oil flows through the fourth valve 34 to outlet 12 and then back to the oil tank 50, realizing the unloading function. When the three-position four-way directional valve 2 is in the right position, the first port 21 and the third port 23 are connected, and the first port 21 and the fourth port 24 are connected. Control oil enters the third valve 33, adjusting the overflow level of the third valve 33 to level two. Control oil enters the unloading control chamber of the fourth valve 34, closing the fourth valve 34, that is, the thirteenth port 342 and the fourteenth port 343 are not connected. Pressure oil flows through the third valve 33 to the outlet 12 and flows back to the oil tank 50. At this time, the system overflow pressure is the sum of the set pressure of the main spring 335 of the third valve 33 and the pressure of the liquid 14 in the pilot hydraulic control chamber acting on the top of the overflow valve core 334 (which can be understood as the main valve core of the existing pilot-operated overflow valve), which is greater than the set pressure of the main spring 335 of the third valve 33. At this time, the third valve 33 can achieve a relatively high pressure overflow, that is, high-pressure overflow.

[0061] Specifically, when the system overflow level needs to be set to the first overflow level, the three-position four-way directional valve 2 is in the left position. At this time, the control oil enters the three-position four-way directional valve 2 from the first interface 21 through the first control flow path 4, and then flows into the unloading control chamber of the fourth valve 34 from the fourth interface 24, causing the valve port of the fourth valve 34 to close. The thirteenth interface 342 and the fourteenth interface 343 are not connected. The pilot hydraulic control chamber 14 of the third valve 33 is connected to the oil tank 50 through the second interface 22, the third interface 23 and the second control flow path 5. The overflow pressure is determined by the set pressure of the main spring 335 of the third valve 33, that is, low-pressure overflow. At this time, the system overflow level is the first overflow level. When the pressure of the hydraulic oil in the system (i.e., the hydraulic pressure output by the working pump) is greater than the first overflow level, the hydraulic oil enters the third valve 33 from the first main flow path 7 through the tenth interface 332, and then flows to the outlet 12 from the eleventh interface 333, and flows back to the oil tank 50. When unloading is required, the three-position four-way directional valve 2 is in the neutral position. Control oil enters the three-position four-way directional valve 2 from the first control flow path 4 via the first interface 21, and then flows from the third interface 22 to the pilot hydraulic control chamber of the third valve 33. The liquid in the unloading control chamber flows back to the oil tank 50 through the fourth interface and the second control flow path. At this time, the thirteenth interface 342 pushes the unloading valve core 344 of the unloading valve to rise, so that the fourth valve 34 is in the open state, that is, the thirteenth interface 342 is connected to the fourteenth interface 343. The pressure oil enters the fourth valve 34 through the fourth main flow path 10 via the thirteenth interface 342, flows out of the fourth valve 34 through the fourteenth interface 343, flows through the fifth main flow path 20 to the outlet 12, and flows back to the oil tank 50. When the system overflow level needs to be set to the second overflow level, the three-position four-way directional valve 2 is in the right position. At this time, control oil enters the three-position four-way directional valve 2 through the first control oil circuit and the first interface 21, and then flows to the third control flow path 6 through the third interface 23, changing the overflow level of the third valve 33 to the second overflow level. Control oil enters the three-position four-way directional valve 2 through the first control oil circuit and the first interface 21, and then flows to the fourth control flow path 9 through the fourth interface 24, and enters the fourth valve 34 through the twelfth interface 341, closing the fourth valve 34. The system overflow level is now the second overflow level. At this time, if the pressure oil in the system is greater than the second overflow level, the pressure oil can overcome the spring force of the third valve 33 and the control oil pressure. That is, the system overflow pressure at this time is the sum of the set pressure of the main spring 335 of the overflow valve core of the third valve 33 and the pressure exerted on the top of the overflow valve core 334 by the liquid pressure of the pilot hydraulic control chamber 14. At this time, the third valve 33 can achieve a relatively high pressure overflow, i.e., high-pressure overflow. It flows from the first main channel 7 through the tenth interface 332 into the third valve 33, and then from the eleventh interface 333 to the outlet 12, and then back to the oil tank 50.

[0062] The effect of this embodiment 2 is as follows: By cooperating with two fixed-pressure-level relief valves, a three-position four-way directional valve 2 can be freely switched between two relief levels without replacing any relief components. When the three-position four-way directional valve 2 is in the left position, the system relief pressure is determined by the set pressure of the main spring 335 of the third valve 33, i.e., low-pressure relief. When the three-position four-way directional valve 2 is in the middle position, the fourth valve 34, the unloading valve, opens for high-flow pressure relief. When the three-position four-way directional valve 2 is in the right position, the system relief pressure is the sum of the set pressure of the main spring 335 of the relief valve core 334 of the third valve 33 and the pressure exerted on the top of the relief valve core 334 by the liquid pressure in the pilot hydraulic control chamber 14. At this time, the third valve 33 can achieve a relatively higher pressure relief, i.e., high-pressure relief. This eliminates the need to separately replace different relief components when changing the hydraulic mechanism, reducing safety or stability issues caused by improper manual installation or unreasonable pressure settings. The first control flow path 4, the second control flow path 5, the third control flow path 6, the first main flow path 7, the second main flow path 8, the fourth control flow path 9, the fourth main flow path 10, and the fifth main flow path 20 are all cast or machined channels inside the housing 1. The connection between the three-position four-way directional valve 2 and the two relief valves (the third valve 33 and the fourth valve 34) requires no external hoses or detachable connectors. This eliminates the physical hazards of external pipelines loosening or fatigue fracture under high-frequency vibration, and reduces the possibility of metal shavings and moisture in the air entering the hydraulic system in working environments with external dust, humidity, or drastic temperature changes. Through the logical coordination of the three-position four-way directional valve 2 and the relief valve unit (the third valve 33 and the fourth valve 33), the three-position four-way directional valve 2 can achieve system unloading and two-stage relief pressure control (high and low pressure) at different positions. This invention not only constructs an internal control logic closed loop, achieving stable pressure regulation and large-flow, shock-free unloading, but also simplifies the structure of multi-stage pressure regulation circuits, improves functional integration, and reduces system cost and failure rate. This reduces the overall manufacturing and assembly costs of the machine and minimizes potential hydraulic failure points at the source.

[0063] This invention also provides a hydraulic system including the aforementioned two-stage relief hydraulic control device. By configuring a three-position four-way directional valve 2 and a valve group 3, when the three-position four-way directional valve 2 is in the left position, the system experiences low-pressure relief. When the three-position four-way directional valve 2 is in the middle position, the system experiences high-flow pressure relief or high-flow unloading. When the three-position four-way directional valve 2 is in the right position, the system experiences high-pressure relief. This eliminates the need to separately replace and install different relief components when changing hydraulic mechanisms, improving the system's versatility and stability. It also reduces safety or stability issues caused by improper manual installation or unreasonable pressure settings, while reducing manual labor intensity and improving the convenience of switching relief pressures.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature 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 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 that the first feature is at a lower horizontal level than the second feature.

[0068] 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.

[0069] Although embodiments of the present invention have been shown and described above, 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 two-stage overflow hydraulic control device for use in a hydraulic system, characterized in that, include: A housing (1) having an inlet (11) and an outlet (12); A three-position four-way directional valve (2) has a first port (21), a second port (22), a third port (23) and a fourth port (24), one of the first port (21) and the second port (22) being connected to the inlet (11) and the other being connected to the outlet (12); A valve assembly (3) is connected to at least one of the third interface (23) and the fourth interface (24), and is also connected to both the inlet (11) and the outlet (12) to regulate the overflow pressure of the hydraulic system.

2. The two-stage overflow hydraulic control device according to claim 1, characterized in that, The valve assembly (3) includes two valve structures.

3. The two-stage overflow hydraulic control device according to claim 2, characterized in that, The valve structure includes a first valve (31) and a second valve (32) having a different pressure rating than the first valve (31). The housing (1) has a first liquid supply path (60) and a first liquid return path (70). The inlet (11) is connected to one end of the first valve (31) and the second interface (22) through the first liquid supply path (60). The outlet (12) is connected to the other end of the first interface (21) and the first valve (31) through the first liquid return path (70).

4. The two-stage overflow hydraulic control device according to claim 3, characterized in that, The first valve (31) has a fifth port (311) and a sixth port (312). The fifth port (311) is connected to the inlet (11) through the first liquid supply path (60), and the sixth port (312) is connected to the outlet (12) through the first liquid return path (70).

5. The two-stage overflow hydraulic control device according to claim 3, characterized in that, The second valve (32) has a seventh port (321) and an eighth port (322), the seventh port (321) being connected to the fourth port (24), and the eighth port (322) being connected to the outlet (12) through a first return flow path (70).

6. The two-stage overflow hydraulic control device according to claim 2, characterized in that, The valve structure includes a third valve (33) and a fourth valve (34). The third interface (23) is connected to the third valve (33), and the fourth interface (24) is connected to the fourth valve (34). The third valve (33) is connected to both the inlet (11) and the outlet (12), and the fourth valve (34) is connected to both the inlet (11) and the outlet (12).

7. The two-stage overflow hydraulic control device according to claim 6, characterized in that, The housing is provided with a first control flow path (4) and a second control flow path (5). The inlet (11) is connected to the first interface (21) through the first control flow path (4), and the radial dimension of the first control flow path (4) gradually increases from the inlet (11) to the first interface (21) in at least part of the direction. The second interface (22) is connected to the outlet (12) through the second control flow path (5).

8. The two-stage overflow hydraulic control device according to claim 7, characterized in that, The housing (1) is provided with a third control flow path (6) and a first main flow path (7). The third valve (33) has a ninth port (331), a tenth port (332), and an eleventh port (333). The ninth port (331) is connected to the third port (23) through the third control flow path (6). The inlet (11) is connected to the tenth port (332) through the first main flow path (7). The outlet (12) is connected to the eleventh port (333) through the second main flow path (8). The third valve (33) is a pilot-operated relief valve, which has a pilot hydraulic control chamber (14) and is connected to the third interface (23) through the ninth interface (331).

9. The two-stage overflow hydraulic control device according to claim 7, characterized in that, The housing (1) is provided with a fourth control flow path (9) and a fourth main flow path (10). The fourth valve (34) has a twelfth port (341), a thirteenth port (342) and a fourteenth port (343). The twelfth port (341) is connected to the fourth port (24) through the fourth control flow path (9). The thirteenth port (342) is connected to the inlet (11) through the fourth main flow path (10). The fourteenth port (343) is connected to the outlet (12) through the fifth main flow path (20).

10. A hydraulic system, characterized in that, Includes the two-stage overflow hydraulic control device as described in any one of claims 1-9.

Images