Hydraulic control system and engineering machinery

Abstract

The utility model relates to the technical field of engineering machinery, in particular to a hydraulic control system and engineering machinery. The hydraulic control system comprises two oil cylinders which are respectively provided with an anti-explosion valve; the oil way unit comprises a first pilot oil way, a second pilot oil way, an anti-explosion valve pilot oil way and a main oil way, the second pilot oil way is configured to provide oil with first preset pressure, the second pilot oil way is connected with one end of the anti-explosion valve pilot oil way, the other end of the anti-explosion valve pilot oil way is connected with the two anti-explosion valves, and the main oil way is connected with the two anti-explosion valves; the main oil way is respectively connected with large cavities of the two oil cylinders; and the electric control unit is configured to control connection and disconnection between the second pilot oil way and the anti-explosion valve pilot oil way. The two anti-explosion valves can be opened at the same time through pilot oil introduced through the second pilot oil way, the problem that the movable arm descends nonlinearly due to the fact that the anti-explosion valves are opened inconsistently is effectively solved, and the safety of engineering machinery is improved.

Description

Technical Field

[0001] This application relates to the field of engineering machinery technology, and in particular to a hydraulic control system and engineering machinery. Background Technology

[0002] An explosion-proof valve is a safety device installed in a hydraulic system. When the hydraulic system malfunctions or a hydraulic hose ruptures, the explosion-proof valve can quickly close, preventing the rapid outflow of hydraulic oil. When applied to excavators, the explosion-proof valve prevents the excavator's boom from rapidly falling due to gravity in the event of a malfunction, effectively avoiding equipment damage or personal injury.

[0003] Currently, excavator booms typically have two hydraulic cylinders, and each cylinder has an explosion-proof valve installed at the oil port of the large chamber. The excavator's hydraulic system is equipped with a pilot oil circuit for the explosion-proof valve, which controls the state of the explosion-proof valve on the cylinder.

[0004] However, during the use of the excavator, when the pilot oil circuit of the explosion-proof valve supplies pilot oil to the two explosion-proof valves, the two explosion-proof valves may not be able to open at the same time, resulting in non-linear boom descent and posing a safety hazard. Utility Model Content

[0005] Based on this, this application provides a hydraulic control system and engineering machinery to solve the problem in the related art that when the pilot oil circuit of the explosion-proof valve supplies pilot oil to the two explosion-proof valves, the two explosion-proof valves may not be able to open simultaneously.

[0006] In a first aspect, embodiments of this application provide a hydraulic control system, including:

[0007] Two hydraulic cylinders, each with an explosion-proof valve installed at the oil port of its large chamber;

[0008] The oil circuit unit includes a first pilot oil circuit, a second pilot oil circuit, an explosion-proof valve pilot oil circuit, and a main oil circuit. The second pilot oil circuit is configured to provide oil at a first preset pressure. One end of the second pilot oil circuit is connected to one end of the explosion-proof valve pilot oil circuit, and the other end of the explosion-proof valve pilot oil circuit is connected to two explosion-proof valves respectively. The main oil circuit is connected to the large chambers of two oil cylinders respectively.

[0009] The electronic control unit is configured to control the on / off connection between the second pilot oil circuit and the explosion-proof valve pilot oil circuit;

[0010] The first preset pressure is higher than the upper limit of the opening pressure of the two explosion-proof valves, and the first preset pressure does not exceed the pilot pressure that the two explosion-proof valves can withstand.

[0011] In one possible implementation, the first pilot oil passage and the second pilot oil passage are respectively connected to the end of the explosion-proof valve pilot oil passage away from the oil cylinder;

[0012] When the oil pressure in the first pilot oil circuit reaches the second preset pressure and the oil pressure in the main oil circuit is normal, the electronic control unit controls the second pilot oil circuit to connect with the explosion-proof valve pilot oil circuit and controls the first pilot oil circuit to isolate from the explosion-proof valve pilot oil circuit; when the oil pressure in the first pilot oil circuit is lower than the second preset pressure or the oil pressure in the main oil circuit is abnormal, the electronic control unit controls the first pilot oil circuit to connect with the explosion-proof valve pilot oil circuit and controls the second pilot oil circuit to isolate from the explosion-proof valve pilot oil circuit.

[0013] The second preset pressure is the pilot pressure when the oil cylinder just starts to move.

[0014] In one possible implementation, the oil circuit unit further includes a shuttle valve, with its first inlet connected to a first pilot oil circuit, its second inlet connected to a second pilot oil circuit, and its outlet connected to the end of the explosion-proof valve pilot oil circuit furthest from the explosion-proof valve.

[0015] In one possible implementation, the electronic control unit includes a first pressure switch, a second pressure switch, and an oil supply mechanism;

[0016] The first pressure switch is connected to the first pilot oil circuit; when the oil pressure in the first pilot oil circuit reaches the second preset pressure, the first pressure switch closes; when the oil pressure in the first pilot oil circuit is lower than the second preset pressure, the first pressure switch opens.

[0017] The second pressure switch is connected to the main oil circuit; when the oil pressure in the main oil circuit is normal, the second pressure switch is closed; when the oil pressure in the main oil circuit is abnormal, the second pressure switch is open.

[0018] The oil supply mechanism is electrically connected to the first pressure switch and the second pressure switch respectively. The end of the second pilot oil circuit away from the pilot oil circuit of the explosion-proof valve is connected to the oil supply mechanism. When both the first pressure switch and the second pressure switch are closed, the oil supply mechanism provides oil with a first preset pressure to the second pilot oil circuit.

[0019] In one possible implementation, the oil supply mechanism includes a pilot lock, an oil tank, and a normally closed solenoid valve. The pilot lock has a pilot lock outlet, the inlet of the normally closed solenoid valve is connected to the pilot lock outlet, the outlet of the normally closed solenoid valve is connected to the end of the second pilot oil circuit away from the pilot oil circuit of the explosion-proof valve, and the return port of the normally closed solenoid valve is connected to the oil tank.

[0020] The normally closed solenoid valve is electrically connected to the first pressure switch and the second pressure switch respectively; when both the first pressure switch and the second pressure switch are closed, the normally closed solenoid valve is open; when at least one of the first pressure switch and the second pressure switch is open, the normally closed solenoid valve is closed.

[0021] In one possible implementation, the electronic control unit further includes a first branch, a second branch, and a relay;

[0022] A relay includes a coil and a switching section;

[0023] The first branch and the second branch are arranged in parallel. The first pressure switch, the second pressure switch and the coil are connected in series on the first branch, and the switch and the normally closed solenoid valve are connected in series on the second branch.

[0024] In one possible implementation, the electronic control unit also includes a main circuit, a power supply, and a fuse. One end of the main circuit is connected to the power supply, and the other end of the main circuit is connected to the first branch circuit and the second branch circuit respectively. The fuse is located on the main circuit.

[0025] In one possible implementation, the oil supply mechanism includes an oil pump and an oil storage unit, with the oil pump inlet connected to the oil storage unit and the oil pump outlet connected to the end of the second pilot oil circuit away from the explosion-proof valve pilot oil circuit.

[0026] The oil pump is electrically connected to the first pressure switch and the second pressure switch respectively; when both the first pressure switch and the second pressure switch are closed, the oil pump drives the oil in the oil storage unit to enter the second pilot oil circuit at the first preset pressure; when at least one of the first pressure switch and the second pressure switch is open, the oil pump is turned off.

[0027] In one possible implementation, the electronic control unit includes a first pressure sensor, a second pressure sensor, a controller, and an oil supply mechanism;

[0028] The first pressure sensor is installed on the first pilot oil line to obtain the oil pressure in the first pilot oil line;

[0029] The second pressure sensor is installed on the main oil line to obtain the oil pressure in the main oil line;

[0030] The oil supply mechanism is connected to the end of the second pilot oil circuit that is furthest from the explosion-proof valve pilot oil circuit;

[0031] The first pressure sensor, the second pressure sensor, and the oil supply mechanism are electrically connected to the controller.

[0032] The controller is configured to control the oil supply mechanism to supply oil with the first preset pressure to the second pilot oil circuit when the oil pressure in the first pilot oil circuit reaches the second preset pressure and the oil pressure in the main oil circuit is normal.

[0033] Secondly, embodiments of this application provide an engineering machine, including the aforementioned hydraulic control system.

[0034] The hydraulic control system and construction machinery provided in this application include two hydraulic cylinders, an oil circuit unit, and an electronic control unit. Explosion-proof valves are installed at the oil ports of the large chambers of the two hydraulic cylinders. The oil circuit unit includes a first pilot oil circuit, a second pilot oil circuit, an explosion-proof valve pilot oil circuit, and a main oil circuit. The electronic control unit is configured to control the connection and disconnection between the second pilot oil circuit and the explosion-proof valve pilot oil circuit. A first preset pressure is higher than the upper limit of the opening pressure of the two explosion-proof valves, but does not exceed the pilot pressure that the two explosion-proof valves can withstand. When it is necessary to open the explosion-proof valves on the two cylinders, the electronic control unit can control the connection between the second pilot oil circuit and the explosion-proof valve pilot oil circuit. This allows the second pilot oil circuit to supply oil with the first preset pressure to the explosion-proof valve pilot oil circuit. Thus, the pilot oil supplied through the second pilot oil circuit can simultaneously open the two explosion-proof valves, effectively solving the problem of non-linear boom descent caused by inconsistent opening of the explosion-proof valves and improving the safety of the construction machinery. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a schematic diagram of the structure of a hydraulic control system in related technologies;

[0037] Figure 2 This is a schematic diagram of the structure of the hydraulic control system provided in the embodiment of this application.

[0038] Explanation of reference numerals in the attached figures:

[0039] 100 - Hydraulic cylinder; 110 - Explosion-proof valve;

[0040] 200 - Hydraulic circuit unit; 210 - Operating handle; 220 - First pilot hydraulic circuit; 230 - Second pilot hydraulic circuit; 240 - Explosion-proof valve pilot hydraulic circuit; 250 - Main hydraulic circuit; 260 - Shuttle valve;

[0041] 300 - Electrical control unit; 310 - First pressure switch; 320 - Second pressure switch; 330 - Oil supply mechanism; 331 - Pilot lock oil outlet; 332 - Normally closed solenoid valve; 333 - Oil tank; 340 - Relay; 341 - Coil; 342 - Switch section; 350 - Fuse; 301 - Main circuit; 302 - First branch circuit; 303 - Second branch circuit; 304 - Power supply; 305 - Grounding point. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar components or components having the same or similar functions throughout. The described embodiments are some, but not all, of the embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0043] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, an indirect connection through an intermediate medium, or the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0044] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0045] The terms “first,” “second,” and “third” (if any) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0046] Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, such that a process, method, system, product, or display that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or display.

[0047] In related technologies, excavators typically have two hydraulic cylinders on their boom, each with an explosion-proof valve installed at the port of its large chamber. The excavator's hydraulic system includes a pilot circuit for the explosion-proof valves, which controls the state of the valves on the cylinders. However, during operation, when the pilot circuit supplies pilot oil to the two explosion-proof valves, sometimes the valves cannot be controlled consistently, resulting in different opening pressures. This causes the two valves to not open simultaneously during boom descent, leading to a non-linear boom descent. When the two valves cannot open simultaneously, the boom descent is slow. After the second valve opens, the boom descent suddenly accelerates, negatively impacting the user experience and posing a safety hazard.

[0048] like Figure 1 As shown, the hydraulic control system controls the movement of two cylinders 100 via operating handle 210 to control the lowering of the boom of the construction machinery. Operating handle 210 controls the pilot oil circuit 240 of the explosion-proof valves to supply pilot oil to the explosion-proof valves 110 on the two cylinders 100. When the pressure of the pilot oil supplied by the pilot oil circuit 240 reaches the opening pressure of the two explosion-proof valves 110, the two explosion-proof valves 110 open, and the oil from the main oil circuit 250 can enter the cylinders 100 through the explosion-proof valves 110. However, when the two explosion-proof valves 110 are not synchronized, their opening pressures are different, resulting in the two explosion-proof valves 110 not opening simultaneously, affecting the boom lowering action.

[0049] The main solutions currently involve requiring suppliers to improve the manufacturing standards of explosion-proof valves and conduct rigorous testing and calibration before shipment to ensure consistent opening pressures and minimize discrepancies. However, these methods place high demands on the supplier's production and inspection standards. Alternatively, one approach is to modify the explosion-proof valve to a magnetically controlled type, addressing the inconsistent opening pressures through structural improvements. However, modifying the internal structure of the explosion-proof valve is costly. Even if the opening pressures of the two explosion-proof valves on the two cylinders are consistent at the factory, their aging rates may differ over time, potentially leading to a significant difference in opening pressures when the boom lowers.

[0050] After repeated consideration and verification, the inventors discovered that by improving the hydraulic circuit unit of the hydraulic control system for construction machinery and introducing an electronic control unit into the hydraulic control system, a pilot oil circuit can be added to the hydraulic circuit unit. When it is necessary to open the explosion-proof valves on two cylinders, the newly added pilot oil circuit can separately supply pilot oil to the explosion-proof valves on the two cylinders. The pressure of this pilot oil is higher than the upper limit of the opening pressure of the two explosion-proof valves, but does not exceed the pilot pressure that the two explosion-proof valves can withstand. This allows the explosion-proof valves on the two cylinders to open simultaneously, effectively solving the problem of nonlinear boom descent caused by the inconsistent control of the two explosion-proof valves, different opening pressures, and the inability of the two explosion-proof valves to open simultaneously when pilot oil is supplied.

[0051] In view of this, the inventors designed a hydraulic control system and engineering machinery. A second pilot oil circuit is connected to an explosion-proof valve pilot oil circuit. The explosion-proof valve pilot oil circuit allows pilot oil to be supplied to the explosion-proof valves on two cylinders. The second pilot oil circuit provides oil at a first preset pressure. This first preset pressure is higher than the upper limit of the opening pressure of the two explosion-proof valves, but does not exceed the pilot pressure that the two explosion-proof valves can withstand. An electronic control unit is included in the hydraulic control system, which controls the connection and disconnection between the second pilot oil circuit and the explosion-proof valve pilot oil circuit. When it is necessary to open the explosion-proof valves on the two cylinders, the second pilot oil circuit supplies oil at the first preset pressure. The pilot oil supplied by the second pilot oil circuit causes the explosion-proof valves on both cylinders to open simultaneously.

[0052] The technical solutions of the hydraulic control system and engineering machinery provided in the embodiments of this application are described in detail below with reference to the accompanying drawings.

[0053] Reference Figure 2 As shown in the embodiment of this application, the hydraulic control system includes two hydraulic cylinders 100, an oil circuit unit 200, and an electronic control unit 300. The two hydraulic cylinders 100 can jointly drive the movement of components of construction machinery, such as the boom of an excavator. Explosion-proof valves 110 are respectively installed at the oil inlets of the large chambers of the two hydraulic cylinders 100. Specifically, each hydraulic cylinder 100 includes a large chamber and a small chamber; the large chamber is the rodless chamber of the hydraulic cylinder 100, and the small chamber is the rod-side chamber of the hydraulic cylinder 100. When the hydraulic control system malfunctions or a hydraulic hose ruptures, the explosion-proof valve 110 can quickly close, thereby preventing the rapid outflow of oil from the large chamber of the hydraulic cylinder 100.

[0054] The oil circuit unit 200 includes a first pilot oil circuit 220, a second pilot oil circuit 230, an explosion-proof valve pilot oil circuit 240, and a main oil circuit 250. The second pilot oil circuit 230 is configured to provide oil at a first preset pressure. One end of the second pilot oil circuit 230 is connected to one end of the explosion-proof valve pilot oil circuit 240, and the other end of the explosion-proof valve pilot oil circuit 240 is connected to two explosion-proof valves 110 respectively.

[0055] Schematic illustration: the first pilot oil circuit 220 can be connected to the operating handle 210, and the user can adjust the oil pressure in the first pilot oil circuit 220 by controlling the operating handle 210. Understandably, the second pilot oil circuit 230 can supply pilot oil to the two explosion-proof valves 110 through the explosion-proof valve pilot oil circuit 240 respectively, and the pressure of the pilot oil is the first preset pressure.

[0056] The main oil circuit 250 is connected to the large chambers of the two hydraulic cylinders 100. The explosion-proof valve 110 controls the connection between the main oil circuit 250 and the hydraulic cylinders 100. That is, when the explosion-proof valve 110 is open, oil in the main oil circuit 250 can enter the large chamber of the hydraulic cylinder 100 to drive its movement; when the explosion-proof valve 110 is closed, it disconnects the main oil circuit 250 from the hydraulic cylinders 100.

[0057] The electronic control unit 300 is configured to control the connection and disconnection between the second pilot oil circuit 230 and the explosion-proof valve pilot oil circuit 240. When the user needs to open the explosion-proof valve 110 on the two cylinders 100, the electronic control unit 300 can control the connection between the second pilot oil circuit 230 and the explosion-proof valve pilot oil circuit 240. At this time, the oil with a first preset pressure in the second pilot oil circuit 230 can be supplied to the explosion-proof valve 110 on the two cylinders 100 through the explosion-proof valve pilot oil circuit 240.

[0058] The first preset pressure is higher than the upper limit of the opening pressure of the two explosion-proof valves 110, and the first preset pressure does not exceed the pilot pressure that the two explosion-proof valves 110 can withstand. It is understood that the pilot oil supplied to the two explosion-proof valves 110 through the second pilot oil circuit 230 and the explosion-proof valve pilot oil circuit 240 can ensure that the two explosion-proof valves 110 open simultaneously without causing damage to them.

[0059] The hydraulic control system provided in this embodiment allows the electronic control unit 300 to control the second pilot oil circuit 230 to connect with the explosion-proof valve pilot oil circuit 240 when it is necessary to open the explosion-proof valve pilot oil circuit 110 on the two oil cylinders 100. This allows the second pilot oil circuit 230 to supply oil with a first preset pressure to the explosion-proof valve pilot oil circuit 240. In this way, the pilot oil supplied through the second pilot oil circuit 230 can simultaneously open the two explosion-proof valves 110, effectively solving the problem of non-linear boom descent caused by inconsistent opening of the explosion-proof valves 110. The construction machinery will not experience the problem of slow boom descent before both explosion-proof valves 110 are opened, and sudden acceleration of boom descent after both explosion-proof valves 110 are opened, due to the two explosion-proof valves 110 not opening simultaneously, thus improving the safety of the construction machinery.

[0060] In one embodiment, such as Figure 2As shown, the first pilot oil passage 220 and the second pilot oil passage 230 are respectively connected to the end of the explosion-proof valve pilot oil passage 240 away from the oil cylinder 100. It can be understood that the pilot oil in the first pilot oil passage 220 can also be directed to the two explosion-proof valves 110 through the explosion-proof valve pilot oil passage 240 respectively.

[0061] When the oil pressure in the first pilot oil circuit 220 reaches the second preset pressure and the oil pressure in the main oil circuit 250 is normal, the electronic control unit 300 controls the second pilot oil circuit 230 to connect with the explosion-proof valve pilot oil circuit 240, and controls the first pilot oil circuit 220 to isolate from the explosion-proof valve pilot oil circuit 240; when the oil pressure in the first pilot oil circuit 220 is lower than the second preset pressure or the oil pressure in the main oil circuit 250 is abnormal, the electronic control unit 300 controls the first pilot oil circuit 220 to connect with the explosion-proof valve pilot oil circuit 240, and controls the second pilot oil circuit 230 to isolate from the explosion-proof valve pilot oil circuit 240. The second preset pressure is the pilot pressure when the cylinder 100 just begins to move.

[0062] Specifically, when the main oil circuit 250 is functioning normally, and the oil pressure in the first pilot oil circuit 220 reaches the pilot pressure at which the cylinder 100 just begins to move, the electronic control unit 300 controls the second pilot oil circuit 230 to connect with the explosion-proof valve pilot oil circuit 240, and controls the first pilot oil circuit 220 to not connect with the explosion-proof valve pilot oil circuit 240. The second pilot oil circuit 230 supplies pilot oil with a first preset pressure to the two explosion-proof valves 110 through the explosion-proof valve pilot oil circuit 240, causing the two explosion-proof valves 110 to open simultaneously. When the main oil circuit 250 is functioning normally, and the oil pressure in the first pilot oil circuit 220 is lower than the second preset pressure, the first pilot oil circuit 220 connects with the explosion-proof valve pilot oil circuit 240.

[0063] When the main oil circuit 250 experiences a leak or pipe burst, the oil pressure in the main oil circuit 250 will be lower than the normal oil pressure. The electronic control unit 300 will control the first pilot oil circuit 220 to connect with the explosion-proof valve pilot oil circuit 240, and control the second pilot oil circuit 230 to disconnect from the explosion-proof valve pilot oil circuit 240. The first pilot oil circuit 220 supplies pilot oil to the two explosion-proof valves 110 through the explosion-proof valve pilot oil circuit 240. When the main oil circuit 250 malfunctions, the opening of the two explosion-proof valves 110 is controlled by the pilot oil pressure supplied by the first pilot oil circuit 220. The explosion-proof valves 110 will only open when the pilot oil pressure reaches the opening pressure of the explosion-proof valves 110; otherwise, they will not open. When the main oil circuit 250 malfunctions and requires pipe replacement, the movement of the construction machinery components can be controlled by the operating handle 210, such as controlling the boom of an excavator to descend slowly, thus improving safety.

[0064] With the above settings, when the main oil circuit 250 malfunctions, the explosion-proof valve 110 can open and close according to the pilot oil pressure supplied by the first pilot oil circuit 220, instead of simply opening the explosion-proof valve 110 by controlling the boom descent via the operating handle 210. This ensures the safety of the explosion-proof valve 110 and improves the safety of the construction machinery.

[0065] Figure 2 As shown, in one possible implementation, the oil circuit unit 200 further includes a shuttle valve 260, with a first inlet connected to a first pilot oil circuit 220, a second inlet connected to a second pilot oil circuit 230, and an outlet connected to the end of the explosion-proof valve pilot oil circuit 240 away from the explosion-proof valve 110.

[0066] This embodiment does not limit the specific structure of the shuttle valve 260; those skilled in the art can select a suitable shuttle valve 260 according to actual needs. Those skilled in the art will understand that only one of the two inlets of the shuttle valve 260 will be connected to the outlet. The shuttle valve 260 can control one of the first pilot oil circuit 220 and the second pilot oil circuit 230 to be connected to the explosion-proof valve pilot oil circuit 240. The shuttle valve 260 has a valve core inside, which can move under the combined action of the oil pressure in the first pilot oil circuit 220 and the oil pressure in the second pilot oil circuit 230, so that the one with the greater oil pressure in the first pilot oil circuit 220 and the second pilot oil circuit 230 is connected to the explosion-proof valve pilot oil circuit 240.

[0067] With the above settings, by controlling the oil pressure in the first pilot oil circuit 220 and the second pilot oil circuit 230, one of them can be connected to the explosion-proof valve pilot oil circuit 240, which is relatively easy to control.

[0068] In other embodiments, switching valves may be respectively provided on the first pilot oil circuit 220 and the second pilot oil circuit 230. By controlling the state of the switching valves on the two pilot oil circuits, the connection state between the two pilot oil circuits and the explosion-proof valve pilot oil circuit 240 can be controlled.

[0069] like Figure 2 As shown, the electronic control unit 300 includes a first pressure switch 310, a second pressure switch 320, and an oil supply mechanism 330.

[0070] The first pressure switch 310 is connected to the first pilot oil circuit 220. When the oil pressure in the first pilot oil circuit 220 reaches the second preset pressure, the first pressure switch 310 closes. When the oil pressure in the first pilot oil circuit 220 is lower than the second preset pressure, the first pressure switch 310 opens. The first pressure switch 310 can acquire the oil pressure in the first pilot oil circuit 220 and adjust its state accordingly. The operating pressure P1 of the first pressure switch 310 is the second preset pressure; the value of P1 can be set as needed and is not uniquely limited here.

[0071] The second pressure switch 320 is connected to the main oil circuit 250. When the oil pressure in the main oil circuit 250 is normal, the second pressure switch 320 is closed. When the oil pressure in the main oil circuit 250 is abnormal, the second pressure switch 320 is open. The second pressure switch 320 can obtain the oil pressure in the main oil circuit 250, and its state is adjusted according to this pressure. The operating pressure P2 of the second pressure switch 320 is the pressure of the internal oil in the main oil circuit 250 during normal operation. The value of P2 can be set as needed and is not limited here.

[0072] The oil supply mechanism 330 is electrically connected to the first pressure switch 310 and the second pressure switch 320 respectively. The end of the second pilot oil circuit 230 away from the explosion-proof valve pilot oil circuit 240 is connected to the oil supply mechanism 330. The oil supply mechanism 330 can supply oil with a first preset pressure to the second pilot oil circuit 230. When both the first pressure switch 310 and the second pressure switch 320 are closed, the oil supply mechanism 330 supplies oil with the first preset pressure to the second pilot oil circuit 230.

[0073] Specifically, when both the first pressure switch 310 and the second pressure switch 320 are closed, the oil supply mechanism 330 supplies oil with a first preset pressure to the second pilot oil circuit 230. The first preset pressure is greater than the second preset pressure. At this time, the second pilot oil circuit 230 is connected to the explosion-proof valve pilot oil circuit 240, and the pilot oil flowing into the second pilot oil circuit 230 can control the simultaneous opening of the two explosion-proof valves 110. When at least one of the first pressure switch 310 and the second pressure switch 320 is disconnected, the oil supply mechanism 330 stops supplying oil to the second pilot oil circuit 230, and the first pilot oil circuit 220 is connected to the explosion-proof valve pilot oil circuit 240. The state of the explosion-proof valve 110 is controlled by the pilot oil pressure flowing into the first pilot oil circuit 220.

[0074] In this structure, the electronic control unit 300 controls whether the oil supply mechanism 330 supplies oil to the second pilot oil circuit 230 according to the state of the two pressure switches, thereby controlling the connection state between the first pilot oil circuit 220, the second pilot oil circuit 230 and the explosion-proof valve pilot oil circuit 240.

[0075] In one specific implementation, such as Figure 2 As shown, the oil supply mechanism 330 includes a pilot lock, an oil tank 333, and a normally closed solenoid valve 332. The pilot lock has a pilot lock outlet 331. The inlet of the normally closed solenoid valve 332 is connected to the pilot lock outlet 331. The outlet of the normally closed solenoid valve 332 is connected to the end of the second pilot oil circuit 230 away from the explosion-proof valve pilot oil circuit 240. The return port of the normally closed solenoid valve 332 is connected to the oil tank 333.

[0076] The normally closed solenoid valve 332 closes when power is off and automatically opens when power is on. The normally closed solenoid valve 332 controls the connection between the pilot lock outlet 331 and the second pilot oil circuit 230. This embodiment does not limit the specific structure of the normally closed solenoid valve 332; those skilled in the art can select a suitable normally closed solenoid valve 332 as needed. When the normally closed solenoid valve 332 is closed, the pilot oil supplied from the pilot lock outlet 331 to the normally closed solenoid valve 332 can flow to the oil tank 333 via the return port of the normally closed solenoid valve 332, where the pilot oil is collected for reuse.

[0077] The normally closed solenoid valve 332 is electrically connected to the first pressure switch 310 and the second pressure switch 320. When both the first pressure switch 310 and the second pressure switch 320 are closed, the normally closed solenoid valve 332 is open. When at least one of the first pressure switch 310 and the second pressure switch 320 is open, the normally closed solenoid valve 332 is closed. Specifically, the normally closed solenoid valve 332 is only energized when both the first pressure switch 310 and the second pressure switch 320 are closed; it is only de-energized when at least one of the first pressure switch 310 and the second pressure switch 320 is open.

[0078] This structure controls whether the normally closed solenoid valve 332 is energized based on the state of the first pressure switch 310 and the second pressure switch 320, thereby controlling whether the oil in the pilot lock outlet 331 flows to the second pilot oil circuit 230.

[0079] Figure 2 As shown, the electronic control unit 300 also includes a first branch 302, a second branch 303, and a relay 340. The relay 340 includes a coil 341 and a switch 342. The first branch 302 and the second branch 303 are arranged in parallel. The first pressure switch 310, the second pressure switch 320, and the coil 341 are connected in series on the first branch 302. The switch 342 and the normally closed solenoid valve 332 are connected in series on the second branch 303.

[0080] For example, the contact input terminal and normally open contact output terminal of the first pressure switch 310 are connected to the first branch 302, the contact input terminal and normally open contact output terminal of the second pressure switch 320 are connected to the first branch 302, and the two ends of the coil 341 are connected to the first branch 302. The two ends of the switch part 342 are connected to the second branch 303.

[0081] When the main oil circuit 250 is functioning normally, the user controls the operating handle 210 to adjust the movement of the machinery's components. When the oil pressure in the first pilot oil circuit 220 reaches the second preset pressure, i.e., the operating pressure P1 of the first pressure switch 310, the first pressure switch 310 activates. The current in the first branch 302 flows through the contact input terminal of the first pressure switch 310 to its normally open contact output terminal, and then through the normally open contact output terminal to the contact input terminal of the second pressure switch 320. Since the main pipeline is functioning normally, the second pressure switch 320 activates. The current in the first branch 302 flows through the contact input terminal of the second pressure switch 320 to its normally open contact output terminal, and then through the normally open contact output terminal to the coil 341. A voltage difference exists across the coil 341, causing the switching part 342 of the relay 340 to activate. The current in the second branch 303 is supplied to the normally closed solenoid valve 332 via the switching part 342 of the relay 340, and the normally closed solenoid valve 332 is energized and opened.

[0082] When the main oil circuit 250 malfunctions, the oil pressure in the main oil circuit 250 will not reach the threshold for the second pressure switch 320 to engage. The second pressure switch 320 will not activate, and the power in the first branch 302 will not be supplied to the coil 341 of the relay 340. The switch part 342 of the relay 340 will disconnect, and the normally closed solenoid valve 332 will be de-energized and closed. The normally closed solenoid valve 332 will disconnect the pilot lock outlet 331 from the second pilot oil circuit 230.

[0083] With the above configuration, the first pressure switch 310 and the second pressure switch 320 can control the energization state of the normally closed solenoid valve 332, and the relay 340 can amplify the signal, ensuring that when both the first pressure switch 310 and the second pressure switch 320 are closed, the normally closed solenoid valve 332 can be stably kept in the open state under energization. This improves the stability of the hydraulic control system.

[0084] In other embodiments, the first pressure switch 310, the second pressure switch 320, and the normally closed solenoid valve 332 may also be arranged in series.

[0085] In one specific implementation, such as Figure 2As shown, the electronic control unit 300 also includes a main circuit 301, a power supply 304, and a fuse 350. One end of the main circuit 301 is connected to the power supply 304, and the other end of the main circuit 301 is connected to the first branch circuit 302 and the second branch circuit 303 respectively. The fuse 350 is disposed on the main circuit 301.

[0086] For example, power supply 304 can accept a 24V input voltage, but it can also be replaced by other voltages suitable for the operation of engineering machinery. Power supply 304 can supply power to the first branch 302 and the second branch 303 respectively through the main circuit 301. Fuse 350 provides safety protection to prevent damage to electrical components in the event of a short circuit. The above configuration ensures the reliability of the electronic control unit 300.

[0087] Figure 2 As shown, the electronic control unit 300 also includes a grounding point 305, and the end of the first branch 302 away from the main branch 301 and the end of the second branch 303 away from the main branch 301 are respectively connected to the grounding point 305.

[0088] This application also provides another implementation of the oil supply mechanism 330. Specifically, the oil supply mechanism 330 includes an oil pump and an oil storage unit. The oil pump inlet is connected to the oil storage unit, and the oil pump outlet is connected to the end of the second pilot oil circuit 230 away from the explosion-proof valve pilot oil circuit 240. For example, the oil storage unit can be an oil tank, oil reservoir, or other device for storing oil. The oil pump can supply the oil in the oil storage unit to the second pilot oil circuit 230.

[0089] The oil pump is electrically connected to the first pressure switch 310 and the second pressure switch 320. When both the first pressure switch 310 and the second pressure switch 320 are closed, the oil pump drives the oil in the oil storage unit to enter the second pilot oil circuit 230 at a first preset pressure. When at least one of the first pressure switch 310 and the second pressure switch 320 is open, the oil pump is shut off.

[0090] Specifically, the oil pump is energized only when both the first pressure switch 310 and the second pressure switch 320 are closed. At this time, the oil pump drives the oil in the oil storage unit to enter the second pilot oil circuit 230 at a first preset pressure. When at least one of the first pressure switch 310 and the second pressure switch 320 is open, the oil pump is de-energized.

[0091] With the above settings, the oil pump is controlled to work based on the status of the first pressure switch 310 and the second pressure switch 320, thereby controlling whether the oil in the oil storage unit enters the second pilot oil circuit 230 at the first preset pressure.

[0092] This application also provides an alternative structure for an electronic control unit that can also control a hydraulic control system.

[0093] Schematic, the electronic control unit 300 includes a first pressure sensor, a second pressure sensor, a controller, and an oil supply mechanism 330. The first pressure sensor is mounted on the first pilot oil passage 220 to obtain the oil pressure in the first pilot oil passage 220. The second pressure sensor is mounted on the main oil passage 250 to obtain the oil pressure in the main oil passage 250. The oil supply mechanism 330 is connected to the end of the second pilot oil passage 230 away from the explosion-proof valve pilot oil passage 240. This embodiment does not limit the specific structure of the first and second pressure sensors; those skilled in the art can select suitable pressure sensors as the first and second pressure sensors as needed.

[0094] The first pressure sensor, the second pressure sensor, and the oil supply mechanism 330 are electrically connected to the controller. The controller is configured to control the oil supply mechanism 330 to supply oil with the first preset pressure to the second pilot oil circuit 230 when the oil pressure in the first pilot oil circuit 220 reaches the second preset pressure and the oil pressure in the main oil circuit 250 is normal.

[0095] Specifically, when the first pressure sensor detects that the oil pressure in the first pilot oil circuit 220 reaches the second preset pressure, it can transmit a signal to the controller. When the second pressure sensor detects that the oil pressure in the main oil circuit 250 is normal, it can transmit a signal to the controller. After receiving signals from both the first and second pressure sensors simultaneously, the controller controls the oil supply mechanism 330 to supply oil with the first preset pressure to the second pilot oil circuit 230. If the controller does not simultaneously receive signals from both the first and second pressure sensors, it controls the oil supply mechanism 330 to stop supplying oil to the second pilot oil circuit 230.

[0096] In this structure, the controller of the electronic control unit 300 controls whether the oil supply mechanism 330 supplies oil to the second pilot oil circuit 230 based on the signal transmitted by the first pressure sensor and the signal transmitted by the second pressure sensor, thereby controlling the connection status between the first pilot oil circuit 220, the second pilot oil circuit 230 and the explosion-proof valve pilot oil circuit 240.

[0097] This application also provides an engineering machine, including the aforementioned hydraulic control system.

[0098] Among them, construction machinery can be excavators or other machinery with moving parts. Taking an excavator as an example, the two cylinders 100 of the hydraulic control system can jointly drive the boom movement of the excavator.

[0099] The construction machinery provided in this application, due to the adoption of the aforementioned hydraulic control system, allows the explosion-proof valves 110 on its two cylinders 100 to open simultaneously, effectively solving the problem of non-linear boom descent caused by the inconsistency of the explosion-proof valves 110 and improving the safety of the construction machinery.

[0100] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A hydraulic control system, characterized in that, include: Two hydraulic cylinders, each equipped with an explosion-proof valve at the oil port of its large chamber; The oil circuit unit includes a first pilot oil circuit, a second pilot oil circuit, an explosion-proof valve pilot oil circuit, and a main oil circuit. The second pilot oil circuit is configured to provide oil at a first preset pressure. One end of the second pilot oil circuit is connected to one end of the explosion-proof valve pilot oil circuit, and the other end of the explosion-proof valve pilot oil circuit is connected to two explosion-proof valves respectively. The main oil circuit is connected to the large chambers of two oil cylinders respectively. The electronic control unit is configured to control the connection and disconnection between the second pilot oil circuit and the explosion-proof valve pilot oil circuit; Wherein, the first preset pressure is higher than the upper limit of the opening pressure of the two explosion-proof valves, and the first preset pressure does not exceed the pilot pressure that the two explosion-proof valves can withstand.

2. The hydraulic control system according to claim 1, characterized in that, The first pilot oil circuit and the second pilot oil circuit are respectively connected to the end of the explosion-proof valve pilot oil circuit that is away from the oil cylinder; When the oil pressure in the first pilot oil circuit reaches the second preset pressure and the oil pressure in the main oil circuit is normal, the electronic control unit controls the second pilot oil circuit to connect with the explosion-proof valve pilot oil circuit, and controls the first pilot oil circuit to isolate from the explosion-proof valve pilot oil circuit; when the oil pressure in the first pilot oil circuit is lower than the second preset pressure or the oil pressure in the main oil circuit is abnormal, the electronic control unit controls the first pilot oil circuit to connect with the explosion-proof valve pilot oil circuit, and controls the second pilot oil circuit to isolate from the explosion-proof valve pilot oil circuit. The second preset pressure is the pilot pressure when the oil cylinder just begins to move.

3. The hydraulic control system according to claim 2, characterized in that, The oil circuit unit also includes a shuttle valve, the first inlet of which is connected to the first pilot oil circuit, the second inlet of which is connected to the second pilot oil circuit, and the outlet of which is connected to the end of the explosion-proof valve pilot oil circuit away from the explosion-proof valve.

4. The hydraulic control system according to claim 2, characterized in that, The electronic control unit includes a first pressure switch, a second pressure switch, and an oil supply mechanism; The first pressure switch is connected to the first pilot oil circuit; when the oil pressure in the first pilot oil circuit reaches the second preset pressure, the first pressure switch closes; when the oil pressure in the first pilot oil circuit is lower than the second preset pressure, the first pressure switch opens. The second pressure switch is connected to the main oil circuit; when the oil pressure in the main oil circuit is normal, the second pressure switch closes. When the oil pressure in the main oil circuit is abnormal, the second pressure switch is disconnected; The oil supply mechanism is electrically connected to the first pressure switch and the second pressure switch respectively. The end of the second pilot oil circuit away from the pilot oil circuit of the explosion-proof valve is connected to the oil supply mechanism. When both the first pressure switch and the second pressure switch are closed, the oil supply mechanism provides oil with a first preset pressure to the second pilot oil circuit.

5. The hydraulic control system according to claim 4, characterized in that, The oil supply mechanism includes a pilot lock, an oil tank, and a normally closed solenoid valve. The pilot lock has a pilot lock outlet. The inlet of the normally closed solenoid valve is connected to the pilot lock outlet. The outlet of the normally closed solenoid valve is connected to the end of the second pilot oil circuit away from the explosion-proof valve pilot oil circuit. The return port of the normally closed solenoid valve is connected to the oil tank. The normally closed solenoid valve is electrically connected to the first pressure switch and the second pressure switch respectively; when both the first pressure switch and the second pressure switch are closed, the normally closed solenoid valve is open; when at least one of the first pressure switch and the second pressure switch is open, the normally closed solenoid valve is closed.

6. The hydraulic control system according to claim 5, characterized in that, The electronic control unit also includes a first branch, a second branch, and a relay; The relay includes a coil and a switching section; The first branch and the second branch are arranged in parallel. The first pressure switch, the second pressure switch and the coil are connected in series on the first branch. The switch part and the normally closed solenoid valve are connected in series on the second branch.

7. The hydraulic control system according to claim 6, characterized in that, The electronic control unit also includes a main circuit, a power supply, and a fuse. One end of the main circuit is connected to the power supply, and the other end of the main circuit is connected to the first branch circuit and the second branch circuit respectively. The fuse is located on the main circuit.

8. The hydraulic control system according to claim 4, characterized in that, The oil supply mechanism includes an oil pump and an oil storage unit. The oil inlet of the oil pump is connected to the oil storage unit, and the oil outlet of the oil pump is connected to the end of the second pilot oil circuit away from the pilot oil circuit of the explosion-proof valve. The oil pump is electrically connected to the first pressure switch and the second pressure switch respectively; when both the first pressure switch and the second pressure switch are closed, the oil pump drives the oil in the oil storage unit to enter the second pilot oil circuit at a first preset pressure; when at least one of the first pressure switch and the second pressure switch is open, the oil pump is turned off.

9. The hydraulic control system according to claim 2, characterized in that, The electronic control unit includes a first pressure sensor, a second pressure sensor, a controller, and an oil supply mechanism; The first pressure sensor is installed on the first pilot oil circuit to obtain the oil pressure in the first pilot oil circuit; The second pressure sensor is installed on the main oil line to obtain the oil pressure in the main oil line; The oil supply mechanism is connected to the end of the second pilot oil circuit that is away from the explosion-proof valve pilot oil circuit; The first pressure sensor, the second pressure sensor, and the oil supply mechanism are all electrically connected to the controller. The controller is configured to control the oil supply mechanism to supply oil with a first preset pressure to the second pilot oil circuit when the oil pressure in the first pilot oil circuit reaches a second preset pressure and the oil pressure in the main oil circuit is normal.

10. An engineering machinery, characterized in that, The hydraulic control system includes any one of claims 1-9.

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