An inlet and outlet independent control valve and system

Abstract

The present application belongs to the technical field of hydraulic pressure, and particularly relates to a control valve and system capable of independently controlling the pressure and flow of an actuator inlet and outlet, comprising a main directional valve, a first one-way overflow valve, a second one-way overflow valve, a proportional flow valve and a proportional overflow valve, wherein the proportional flow valve inlet C1 is communicated with a main oil path, the proportional flow valve outlet D1 is communicated with the main directional valve inlet P, the proportional overflow valve inlet is communicated with the main directional valve outlet T, and the proportional overflow valve outlet is communicated with an oil tank. The plug-in control valve is used to independently control the pressure and flow of the main directional valve inlet and outlet, to realize the independent control function of the inlet and outlet, and the control mode is mature and easy to realize large flow and low pressure loss control. When the zero position is small flow, the main directional valve four-side linkage throttle control valve port flow is controlled, the control characteristic is good, and the structure is simple and easy to realize.

Description

Technical Field

[0001] This invention belongs to the field of hydraulic technology, specifically relating to a control valve and system capable of independently controlling the pressure and flow rate of the actuator's inlet and outlet oil ports. Technical Background

[0002] Current construction machinery uses multi-way valves to control the speed and direction of actuator movement. Each throttling side of the multi-way valve is mechanically fixed and machined onto the same valve core. When controlling a hydraulic actuator, the inlet and outlet ports of the multi-way valve are throttled simultaneously, resulting in significant energy consumption and heat generation in the system. To prevent the output flow of the multi-way valve from being affected by changes in load pressure, pressure compensation valves are needed at the inlet or outlet of the multi-way valve to maintain a constant pressure difference. For overload conditions, balancing valves or throttling valves are often added to create back pressure, and the resulting pressure loss further reduces the system's energy efficiency. Moreover, this method can only control the pressure or flow of one chamber of the actuator at a time, resulting in poor controllability, especially under overload conditions.

[0003] To address the aforementioned issues, existing solutions employ independent inlet and outlet control technology to separately control the pressure and flow in the two chambers of the actuator. This breaks the traditional linkage between the inlet and outlet ports of control valves, increasing control freedom and reducing system pressure loss. A common approach is to use a loop principle with two three-position three-way valves or four two-position two-way valves. Caterpillar Inc.'s patent application number US14696869 discloses a loop principle for an independent inlet and outlet control system consisting of four sets of displacement force feedback two-way proportional throttle valves. This system has been applied in Caterpillar's medium and large excavators, achieving good energy-saving results. However, this structure completely deviates from the configuration of existing multi-way valves used in construction machinery, requiring redesign and development. The combination of four independently controlled valves controlling the same actuator results in a complex overall structure and high manufacturing difficulty, especially since the displacement force feedback principle makes the valve characteristics susceptible to the influence of the feedback spring. Currently, no domestic hydraulic companies are capable of developing related products; research is primarily concentrated in universities.

[0004] To improve system response speed and control accuracy, existing research on independent inlet / outlet control systems often employs high-performance proportional servo valves and sensors. However, these are incompatible with mature technologies for controlling positive and negative flow rates and mechanical-hydraulic and electro-hydraulic loads, and are also unsuitable for the harsh operating environments and requirements of construction machinery such as excavators and loaders. Eaton Corporation's patent application US13939963 discloses an independent inlet / outlet control valve configuration consisting of two three-position three-way valves, integrating pressure and valve core displacement sensors. Each three-position three-way proportional valve uses a two-stage structure, with a high-frequency voice coil motor and feedback spring rod in the pilot stage. It employs an electro-closed-loop control system to adjust the displacement (opening area) of the main valve core. While the overall principle is similar to a servo valve, and it possesses good control characteristics, it is difficult to adapt to the harsh operating environments and requirements of construction machinery. Summary of the Invention

[0005] To address the aforementioned issues, this invention, based on practical considerations, aims to provide an independent inlet / outlet control valve and system that features low pressure loss, simple structure, strong compatibility, low cost, and ease of engineering application, facilitating easy matching with the host machine.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] An independent control valve for oil inlet and outlet includes a main directional valve, a first one-way relief valve, and a second one-way relief valve. Its features include: a further addition of a proportional flow valve and a proportional relief valve; the proportional flow valve inlet C1 is connected to the main oil circuit; the proportional flow valve outlet D1 is connected to the main directional valve inlet P; the proportional relief valve inlet is connected to the main directional valve outlet T; and the proportional relief valve outlet is connected to the oil tank.

[0008] The aforementioned independent control valve for inlet and outlet oil ports, a proportional flow valve, includes a main valve sleeve, a main valve core, a return spring, a pilot valve, a first pressure sensor, a second pressure sensor, a flow controller, a proportional amplifier, a subtractor, an interpolation controller, and a digital flow compensation model. The main valve core is provided with a valve core flow channel L1 and a throttling groove C. x The main valve sleeve is equipped with a throttling control edge F1. The main valve core is arranged inside the main valve sleeve via a through shaft. The main valve core and the main valve sleeve form the main valve inlet C1, the main valve outlet D1, and the main valve control chamber E1. The main valve inlet C1 is connected to the throttling groove C through the valve core flow channel L1. x throttling groove C x The throttling edge F1 is connected to the main valve control chamber E1; the first pressure sensor is installed in the chamber connected to the main valve control chamber E1, and the second pressure sensor is installed in the chamber connected to the main valve outlet D1.

[0009] The aforementioned independent control valve for inlet and outlet ports includes a pilot valve core, a pilot valve body, a pilot valve spring, and a proportional electromagnet. The pilot valve core is arranged within the pilot valve body. One end of the pilot valve spring acts on the pilot valve body, and the other end acts on the pilot valve core. The proportional electromagnet is connected to the pilot valve body, and the armature of the proportional electromagnet controls the displacement of the pilot valve core. The pilot valve inlet X1 is connected to the main valve control chamber E1, and the pilot valve outlet Y1 is connected to the main valve outlet D1.

[0010] The aforementioned independent control valve for oil inlet and outlet has pressure sensors I and II output signals connected to a flow controller. The flow controller outputs a signal input to a proportional amplifier, which controls the output force of a proportional electromagnet. The flow controller includes a subtractor, an interpolation controller, and a digital flow compensation model.

[0011] The aforementioned independent inlet and outlet control valve, a proportional flow valve, further includes a pilot valve displacement sensor. This sensor is integrated into the proportional electromagnet and detects the pilot valve core displacement and velocity by detecting the position of the electromagnet core. Alternatively, it can be mounted on the pilot valve core via a through shaft to directly detect the pilot valve core's position and velocity. The flow controller output signal and the pilot valve displacement sensor output signal are jointly input to the pilot valve displacement controller. After processing by a proportional amplifier, the signals control the proportional electromagnet to output force or displacement.

[0012] The aforementioned independent control valve for inlet and outlet ports, a proportional flow valve, further integrates pressure control functions and is equipped with a third pressure sensor, a pressure controller, and a control switch. The third pressure sensor is installed in the cavity connected to the oil inlet C1 of the proportional flow valve. The signal output terminals of the second and third pressure sensors are connected to the pressure controller. The output signals of the pressure controller and the flow controller are connected to the input terminal of the control switch. The output terminal of the control switch controls the proportional electromagnet through a proportional amplifier. By switching the position of the control switch, pressure control or flow control of the proportional flow valve can be selected.

[0013] The aforementioned independent control valve for inlet and outlet ports can also have its main directional valve outlet T configured as the proportional flow valve, with the proportional flow valve inlet C1 connected to the main directional valve outlet T and the proportional flow valve outlet D1 connected to the oil tank.

[0014] The aforementioned independent control valve for inlet and outlet ports includes a main directional valve that is: a closed-center multi-way directional valve with a load-sensitive detection port LS; or an open-center multi-way directional valve with a neutral position oil circuit; or a three-position four-way proportional directional valve.

[0015] The aforementioned independent control valve for oil inlet and outlet ports includes a main directional valve that is one of hydraulic control, electro-proportional direct control, or electro-hydraulic proportional control.

[0016] The aforementioned independent control valve for inlet and outlet ports includes a proportional flow valve installed at the P port and / or T port of the main directional valve. The proportional flow valve comprises a main valve sleeve, a main valve core, and a pilot valve. The control chamber of the main valve is connected to a first pressure sensor, and the outlet port of the main valve is connected to a second pressure sensor. The signal output terminals of the first and second pressure sensors are connected to a flow controller. The output signal of the flow controller is input to a proportional amplifier, and the proportional amplifier is connected to and controls the proportional electromagnet.

[0017] Includes the following steps:

[0018] Step 1: Obtain the digital flow compensation model of the pilot valve through experimental or simulation methods;

[0019] Step 2: Discretize the digital traffic compensation model and use... The values ​​are stored in the interpolation controller in the form of i = 1, 2, 3, ..., n; j = 1, 2, 3, ..., m;

[0020] Step 3: Combine the pressure signals p detected by pressure sensor I and pressure sensor II. A p B In the input flow controller, the pilot valve port pressure difference Δp is obtained in real time through the subtractor. * Input to the interpolation controller, and simultaneously input the desired flow rate q d Input into the interpolation controller;

[0021] Step 4: Based on the interpolation principle A flow correction signal is generated, and the displacement of the pilot valve solenoid is compensated based on this flow correction signal.

[0022] A load-sensitive system with independent inlet and outlet control includes a power source, a load-sensitive hydraulic pump, a main safety valve, and at least two sets of control valves, wherein at least one set of control valves is an independent inlet and outlet control valve; the power source and the load-sensitive hydraulic pump are coaxially mechanically connected, the outlet of the load-sensitive hydraulic pump is connected to the main safety valve and the main oil circuit, the inlets of each set of control valves share a unified main oil circuit, and the outlets are connected to a unified return oil circuit and then connected to the oil tank.

[0023] The independent control valves for the inlet and outlet oil ports are:

[0024] The main directional valve is a closed-center multi-way directional valve with a load-sensitive detection port LS; the closed-center multi-way directional valve is equipped with a proportional flow valve at port P and a proportional relief valve at port T; the proportional flow valve inlet C1 is connected to the main oil circuit, and the proportional flow valve outlet D1 is connected to the closed-center multi-way directional valve inlet P; the proportional relief valve inlet is connected to the closed-center multi-way directional valve return port T, and the proportional relief valve outlet is connected to the return oil circuit.

[0025] or

[0026] The main directional valve is a closed-center multi-way directional valve with a load-sensitive detection port LS. A proportional flow valve is installed before the inlet port P of the closed-center multi-way directional valve. The inlet port C1 of the proportional flow valve is connected to the main oil circuit, and the outlet port D1 of the proportional flow valve is connected to the inlet port P of the closed-center multi-way directional valve. A proportional flow valve is added at the return port T of the closed-center multi-way directional valve. The inlet port of the proportional flow valve is connected to the return port T of the closed-center multi-way directional valve, and the outlet port of the proportional flow valve is connected to the oil tank.

[0027] An independent inlet and outlet flow matching system includes a power source, a main hydraulic pump, a main safety valve, and at least two sets of control valves, wherein at least one set of control valves is an independent inlet and outlet control valve; the power source and the hydraulic pump are coaxially mechanically connected, the outlet of the hydraulic pump is connected to the main safety valve and the main oil circuit, the inlets of each set of control valves share a unified main oil circuit, and the outlets are connected to the oil tank through a unified return oil circuit.

[0028] The power source mentioned is either an electric motor or a diesel engine;

[0029] The main hydraulic pump is one of a fixed displacement pump and an electro-proportional variable displacement pump.

[0030] The independent control valves for the inlet and outlet oil ports are as follows:

[0031] The main directional valve is a three-position four-way proportional directional valve. A proportional flow valve is installed before the oil inlet P port of the three-position four-way proportional directional valve, and a proportional relief valve is installed at the T port. The oil inlet C1 of the proportional flow valve is connected to the main oil circuit, and the oil outlet D1 of the proportional flow valve is connected to the oil inlet P of the three-position four-way proportional directional valve. The oil inlet of the proportional relief valve is connected to the oil outlet T of the three-position four-way proportional directional valve, and the oil outlet of the proportional relief valve is connected to the oil tank.

[0032] or

[0033] The main directional valve is a three-position four-way proportional directional valve. A proportional flow valve is added before the oil inlet P of the three-position four-way proportional directional valve. The oil inlet C1 of the proportional flow valve is connected to the main oil circuit, and the oil outlet D1 of the proportional flow valve is connected to the oil inlet P of the three-position four-way proportional directional valve. A proportional flow valve is installed at the oil outlet T of the three-position four-way proportional directional valve. The oil inlet of the proportional flow valve is connected to the oil outlet T of the three-position four-way proportional directional valve, and the oil outlet of the proportional flow valve is connected to the oil tank.

[0034] A negative flow system with independent inlet and outlet control is characterized by comprising a power source, a negative flow throttling port, a negative flow detection oil circuit, a negative flow control hydraulic pump, a main safety valve, and at least two sets of control valves, wherein at least one set of control valves is an independent inlet and outlet control valve; the power source and the negative flow control hydraulic pump are coaxially mechanically connected; the outlet of the negative flow control hydraulic pump is connected to the main safety valve and the main oil circuit; the inlets of each set of control valves share a unified main oil circuit; the outlets are connected to the oil tank through a unified return oil circuit; the outlet F of the main directional valve's neutral position oil circuit is connected to the negative flow throttling port and the negative flow detection oil circuit; the negative flow detection oil circuit is connected to the negative flow controller of the negative flow control hydraulic pump; and the negative flow throttling port is connected to the oil tank.

[0035] The independent control valves for the inlet and outlet oil ports are:

[0036] The main directional valve is an open-center multi-way directional valve with a neutral position oil circuit. The inlet P of the open-center multi-way directional valve is equipped with a proportional flow valve, and the outlet T of the open-center multi-way directional valve is equipped with a proportional relief valve. The inlet C1 of the proportional flow valve is connected to the main oil circuit, and the outlet D1 of the proportional flow valve is connected to the inlet P of the open-center multi-way directional valve. The inlet of the proportional relief valve is connected to the outlet T of the open-center multi-way directional valve, and the outlet of the proportional relief valve is connected to the oil tank.

[0037] or

[0038] The main directional valve is an open-center multi-way directional valve with a center position oil circuit. A proportional flow valve is added before the oil inlet P of the open-center multi-way directional valve. The oil inlet C1 of the proportional flow valve is connected to the main oil circuit, and the oil outlet D1 of the proportional flow valve is connected to the oil inlet P of the three-position four-way proportional directional valve. A proportional flow valve is installed at the oil outlet T of the open-center multi-way directional valve. The oil inlet of the proportional flow valve is connected to the oil outlet T of the open-center multi-way directional valve, and the oil outlet of the proportional flow valve is connected to the oil tank.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] This invention employs cartridge-type control valves to independently control the pressure and flow rate at the inlet and outlet of the main directional valve, achieving independent control of the inlet and outlet ports. The control method is mature and easy to implement for high flow rates and low pressure loss. When the flow rate is zero or very low, the flow rate at the valve port is controlled by the four-sided linkage throttling of the main directional valve. This results in good control characteristics, a simple structure, and ease of implementation.

[0041] This invention can be well matched and integrated with existing multi-way valve structures and electro-hydraulic control technology. It can be directly matched with existing three-position four-way directional valves, positive / negative flow, load-sensitive multi-way valves, and their corresponding system control principles. It has good compatibility, low cost, and strong practical engineering application value.

[0042] This invention proposes an interpolation flow control algorithm for a proportional flow valve. By calculating and detecting the differential pressure at the pilot valve port and the flow rate at the pilot valve port, the pilot valve core displacement is dynamically adjusted, and the main valve flow rate is amplified by the pilot valve flow rate. This achieves precise control of the valve port flow rate under varying load conditions, solving the problems of large pressure loss, small flow capacity, and poor stability caused by traditional mechanical differential pressure compensators. Based on the same structure, it also has a closed-loop safety redundancy function. When components such as sensors fail, the proportional flow valve can automatically switch to internal feedback control to prevent system loss of control.

[0043] This invention adds different types of flow control, pressure control, and composite control cartridge control valves to the inlet and outlet of the main directional valve. It can easily realize multiple composite control modes such as pressure / flow, pressure / pressure, and flow / pressure at the inlet and outlet of the multi-way valve without the need for complex control algorithms.

[0044] This invention can easily achieve modular design, various cartridge valves can be replaced in situ, and the same system can be configured differently according to different actuator operating conditions and action requirements. Different types of inlet and outlet cartridge control valve combinations can be used in a targeted manner, or cartridge valves can be omitted and controlled according to the main directional valve function. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the first structural principle of the independent oil inlet and outlet control valve of the present invention;

[0046] Figure 2 This is a schematic diagram of the second structural principle and control method of the proportional flow valve of the present invention;

[0047] Figure 3 This is a schematic diagram of the second structural principle of the independent oil inlet and outlet control valve of the present invention;

[0048] Figure 4 This is a schematic diagram of the third structure of the independent oil inlet and outlet control valve of the present invention;

[0049] Figure 5 This is a schematic diagram of the application of the present invention to a load-sensitive system;

[0050] Figure 6 This is a schematic diagram of the application of the present invention in a traffic matching system;

[0051] Figure 7 This is a schematic diagram of the application of the present invention in a negative flow control system.

[0052] In the diagram, 1-main directional valve, 2-first check relief valve, 3-second check relief valve, 5-proportional relief valve, 27-power source, 28-load-sensitive hydraulic pump, 29-main safety valve, 30-main oil circuit, 31-return oil circuit, 32-shuttle valve, 33-first group multi-way valve, 34-second group multi-way valve, 35-third group multi-way valve, 36-hydraulic cylinder, 37-hydraulic motor, 38-first proportional pressure reducing valve, 39-second proportional pressure reducing valve, 40-negative flow throttle port, 41-negative flow detection oil circuit, 42-main hydraulic pump, 43-negative flow control hydraulic pump, A-first working port, B-second working port, P-main directional valve inlet, T-main directional valve outlet, LS-load-sensitive detection port, E-neutral oil circuit inlet, F-neutral oil circuit outlet;

[0053] 4-Proportional flow valve, including: 7-Main valve sleeve, 8-Main valve core, 9-Return spring, 10-Pilot valve, 11-Pilot valve core, 12-Pilot valve body, 13-Pilot valve spring, 14-Proportional electromagnet, 15-Pressure sensor I, 16-Pressure sensor II, 17-Flow controller, 18-Proportional amplifier, 19-Subtractor, 20-Interpolation controller, 21-Digital flow compensation model, 22-Pilot valve displacement sensor, 23-Pilot valve displacement controller, 24-Pressure sensor III, 25-Pressure controller, 26-Control switch, C1-Proportional flow valve inlet, D1-Proportional flow valve outlet, X1-Pilot valve inlet, Y1-Pilot valve outlet, L1-Valve core flow channel, C x - Throttling groove, E1- Main valve control chamber, F1- Throttling control side. Detailed Implementation

[0054] Figure 1 The diagram illustrates the first structural principle of the independent inlet and outlet control valve of the present invention, comprising a main directional valve 1, a first one-way relief valve 2, and a second one-way relief valve 3. The first working port A of the main directional valve 1 is connected to the first one-way relief valve 2, and the second working port B of the main directional valve 1 is connected to the second one-way relief valve 3. The main directional valve 1 employs a hydraulically controlled closed-center multi-way directional valve with a load-sensitive detection port LS. A proportional flow valve 4 is added before the inlet P of the main directional valve 1. The first main valve inlet C1 of the flow amplification proportional flow valve 4 is connected to the main oil circuit, and the first main valve outlet D1 is connected to the inlet P of the main directional valve. A proportional relief valve 5 is added after the outlet T of the main directional valve 1. The inlet of the proportional relief valve 5 is connected to the return port T of the main directional valve, and the outlet of the proportional relief valve 5 is connected to the oil tank.

[0055] like Figure 1 As shown, the proportional flow valve 4 includes: a main valve sleeve 7, a main valve core 8, a return spring 9, and a pilot valve 10; the main valve core 8 is additionally provided with a valve core flow channel L1 and a throttling groove C. xThe main valve core 8 is arranged inside the main valve sleeve 7, forming the main valve inlet C1, the main valve outlet D1, and the main valve control chamber E1 with the main valve sleeve 7. The main valve inlet C1 is connected to the throttling groove C through the valve core flow channel L1. x throttling groove C x The pilot valve 10 is connected to the main valve control chamber E1, which is connected to the pilot valve inlet X1, and the pilot valve outlet Y1 is connected to the main valve outlet D1. The pilot valve 10 includes: a pilot valve core 11, a pilot valve body 12, a pilot valve spring 13, and a first proportional electromagnet 14. The pilot valve core 11 is arranged in the pilot valve body 12. One end of the pilot valve spring 13 acts on the pilot valve body 12, and the other end acts on the pilot valve core 11. The proportional electromagnet 14 is connected to the pilot valve body 12, and the armature of the proportional electromagnet 14 acts on the other end face of the pilot valve core 12.

[0056] The proportional flow valve 4 employs an interpolation flow control method and is equipped with a first pressure sensor 15, a second pressure sensor 16, a flow controller 17, and a proportional amplifier 18. The first pressure sensor 15 and the second pressure sensor 16 are respectively connected to the pilot valve inlet and the main valve outlet D1, and transmit the detected pressure signal p. A p B In the input flow controller 17, after processing by the flow controller 17, the proportional electromagnet 14 is controlled by the proportional amplifier 18; the flow controller 17 includes a subtractor 19, an interpolation controller 20, and a digital flow compensation model 21.

[0057] The specific control method is as follows: A digital flow compensation model 21 for the pilot valve is obtained through experimentation or simulation. A surface model is used, where the X-axis represents the flow compensation control signal, the Y-axis represents the square root of the main valve pressure difference, and the Z-axis represents the output flow rate. Then, the digital flow compensation model 21 is discretized and... The values ​​are stored in the interpolation controller 20 in the form of i = 1, 2, 3, ..., n; j = 1, 2, 3, ..., m; Then the pressure signals p detected by the first pressure sensor 15 and the second pressure sensor 16 A p B In the input flow controller 17, the real-time pilot valve pressure difference Δp is obtained through the subtractor 19. * The input is entered into the interpolation controller 20, and the desired flow rate q is simultaneously input into the interpolation controller 20. d By inputting the interpolation controller 20, the interpolation principle can be applied. The flow correction signal is calculated, and the displacement of the electromagnet of the pilot valve 10 can be compensated by controlling the flow correction control signal. According to the displacement-flow compensation principle of the flow amplification valve, the compensation of the displacement of the pilot valve 10 will be fed back to the flow of the main valve, thereby realizing the flow compensation function of the main valve.

[0058] Figure 2 The diagram illustrates the second structural principle and control method of the proportional flow valve 4. The proportional flow valve 4 is further equipped with a pilot displacement sensor 22, which is connected to a proportional electromagnet 14. The feedback signal from the pilot displacement sensor 22 is input to a pilot valve core displacement controller 23. After processing by the pilot valve core displacement controller 23, it provides closed-loop control of the first proportional electromagnet 14. The proportional flow valve 4 further integrates pressure control functionality, adding a third pressure sensor 24, a pressure controller 25, and a control switch 26. The third pressure sensor 24 is connected to the main valve inlet C1 of the proportional flow valve 4. The signal outputs of the second and third pressure sensors 16 are connected to the pressure controller 25. The outputs of the pressure controller 25 and the flow controller 17 are connected to the input of the control switch 26. The output of the control switch 26 controls the proportional electromagnet 14 through a proportional amplifier 18. By switching the control switch 26, the proportional flow valve 4 can be selected for either pressure control or flow control.

[0059] Figure 3 The diagram shows the second structural principle of the independent inlet and outlet control valve of the present invention, which is similar to... Figure 1 The difference is that the main directional valve 1 uses an electro-proportional controlled three-position four-way directional valve.

[0060] Figure 4 The diagram shows the third structural principle of the independent inlet and outlet control valve of the present invention, which is similar to... Figure 1 The difference is that the main directional valve 1 adopts an open-center multi-way directional valve with a neutral position oil circuit controlled by the first proportional pressure reducing valve 38 and the second proportional pressure reducing valve 39, and integrates a flow regeneration function. A proportional flow valve 4 is added after the oil outlet T of the main directional valve 1. The oil inlet C1 of the proportional flow valve 4 is connected to the oil return T of the main directional valve 1, and the oil return D1 of the proportional flow valve 4 is connected to the oil tank.

[0061] Example 1:

[0062] Figure 5 The application is shown below. Figure 1 The load-sensitive system, consisting of independent inlet and outlet control valves, includes a power source 27, a load-sensitive hydraulic pump 28, a main safety valve 29, and three sets of multi-way valves. Each set of multi-way valves shares a common main oil circuit 30 and is connected to the oil tank via a common return oil circuit 31. The outlet of the load-sensitive hydraulic pump 28 is connected to the main safety valve 29 and the main oil circuit 30, while the return oil circuit 31 is connected to the oil tank. The first set of multi-way valves 33 is an independent inlet and outlet control valve, connected to... Figure 1The difference between the independent inlet and outlet control valves shown is that the proportional flow valve installed before the inlet P of the main directional valve 1 integrates pressure control function, and the proportional flow valve with integrated pressure control function is also added to the return port T of the main directional valve 1; the multi-way valve 34 in group II is a conventional load-sensitive multi-way valve; the multi-way valve in group III is an independent inlet and outlet control valve, and... Figure 1 The connection relationship and composition of the independent control valves for the inlet and outlet ports shown are the same.

[0063] The power source 27 is one of the following: internal combustion engine, three-phase asynchronous motor, variable frequency motor, and servo motor.

[0064] Example 2:

[0065] Figure 6 The application is shown below. Figure 4 The flow matching system, consisting of independent inlet and outlet control valves, includes a power source 27, a hydraulic pump 42, a main safety valve 29, and three sets of multi-way valves. From left to right, these are set as follows: Group I multi-way valve 33, Group II multi-way valve 34, and Group III multi-way valve 35. All independent inlet and outlet control valves share a common main oil circuit 30 and are connected to the oil tank via a common return oil circuit 31. The power source 27 is a servo motor, and the hydraulic pump 42 is a fixed displacement pump. The outlet of the hydraulic pump 42 is connected to the main safety valve 29 and the main oil circuit 30. The outlet of the main safety valve 29 and the return oil circuit 31 are connected to the oil tank. Group I multi-way valve 33 and Group III multi-way valve 34 are independent inlet and outlet control valves, and Group II multi-way valve 35 is a three-position four-way proportional valve.

[0066] The third group of multi-way valves 35 and Figure 4 The inlet and outlet independent control valves shown have the same connection relationship and composition. The multi-way valve 33 in group I is... Figure 4 The difference between the independent control valves for the inlet and outlet ports shown is that a proportional flow valve 4 is set after the outlet T of the main directional valve 1. The inlet C1 of the first main valve of the proportional flow valve 4 is connected to the return port T of the main directional valve, and the outlet D1 of the first main valve is connected to the return oil circuit 31.

[0067] Example 3:

[0068] Figure 7 The application is shown below. Figure 5 The negative flow control system shown consists of independent inlet and outlet control valves, including a power source 27, a negative flow control hydraulic pump 43, a main safety valve 29, and three sets of multi-way valves, from bottom to top: multi-way valve group I 33, multi-way valve group II 34, and multi-way valve group III 35. Multi-way valve group I 33, multi-way valve group II 34, and multi-way valve group III 35 are all independent inlet and outlet control valves. All the independent inlet and outlet control valves share a unified main oil circuit 30 and are connected to the oil tank through a unified return oil circuit 31.

[0069] Among them, the power source 27 is a diesel engine, the outlet of the negative flow control hydraulic pump 43 is connected to the main safety valve 29 and the main oil circuit 30, and the return oil circuit 31 is connected to the oil tank.

[0070] Group I multi-way valve 33, and Figure 7 The inlet and outlet independent control valves shown have the same connection relationship and composition structure. The oil inlet E of the main directional valve 1 is connected to the oil outlet of the negative flow control hydraulic pump 43. The oil outlet F of the main directional valve 1 is connected to the oil inlet E of the directional valve in the second multi-way valve 34.

[0071] Group II multi-way valve 34, and Figure 7 The difference between the independent inlet and outlet control valves shown is that a proportional relief valve 5 is added after the oil outlet T of the main directional valve 1. The oil inlet of the proportional relief valve 5 is connected to the oil return T of the main directional valve, the oil outlet of the proportional relief valve 5 is connected to the oil return circuit 31, and the oil outlet F of the middle position oil circuit of the main directional valve 1 is connected to the oil inlet E of the middle position oil circuit of the directional valve in the tail valve group 53.

[0072] Group III multi-way valve 35, and Figure 7 The difference between the inlet and outlet independent control valves shown is that the proportional flow valve 4 added after the return port T of the main directional valve 1 integrates the pressure control function; the oil outlet F of the middle position oil circuit of the main directional valve 1 is connected to the negative flow throttle port 40 and the negative flow detection oil circuit 41, the negative flow detection oil circuit 41 is connected to the negative flow control hydraulic pump 43 negative flow controller, and the negative flow throttle port 40 is connected to the oil tank.

[0073] The above description merely illustrates several embodiments of the present invention, and while the descriptions are specific and detailed, they are not intended to limit the scope of protection of the present invention. The present invention is not limited to the aforementioned circuits, but can also be used in other multi-actuator construction machinery such as excavators, loaders, cranes, and telescopic forklifts.

Claims

1. An independent control valve for oil inlet and outlet, comprising a main directional valve (1), a first one-way relief valve (2), and a second one-way relief valve (3), characterized in that: A proportional flow valve (4) and a proportional relief valve (5) are further added. The oil inlet C1 of the proportional flow valve is connected to the main oil circuit (30), the oil outlet D1 of the proportional flow valve is connected to the oil inlet P of the main directional valve, the oil inlet of the proportional relief valve is connected to the oil outlet T of the main directional valve, and the oil outlet of the proportional relief valve is connected to the oil tank. The proportional flow valve includes a main valve sleeve (7), a main valve core (8), a return spring (9), a pilot valve (10), a first pressure sensor (15), a second pressure sensor (16), a flow controller (17), a proportional amplifier (18), a subtractor (19), an interpolation controller (20), and a digital flow compensation model (21). The main valve core is provided with a valve core flow channel L1 and a throttling groove Cx, and the main valve sleeve is provided with a control throttling edge F1. The main valve core is arranged in the main valve sleeve. The main valve core and the main valve sleeve form the main valve inlet C1, the main valve outlet D1 and the main valve control chamber E1. The main valve inlet C1 is connected to the throttling groove Cx through the valve core flow channel L1. The throttling groove Cx is connected to the main valve control chamber E1 through the control throttling edge F1. The first pressure sensor (15) is installed in the cavity connected to the main valve control chamber E1, and the second pressure sensor (16) is installed in the cavity connected to the main valve outlet D1. The pilot valve (10) includes a pilot valve core (11), a pilot valve body (12), a pilot valve spring (13), and a proportional electromagnet (14). The pilot valve core is arranged in the pilot valve body. One end of the pilot valve spring acts on the pilot valve body and the other end acts on the pilot valve core. The proportional electromagnet is connected to the pilot valve body, and the armature of the proportional electromagnet controls the displacement of the pilot valve core. The pilot valve inlet X1 is connected to the main valve control chamber E1, and the pilot valve outlet Y1 is connected to the main valve outlet D1. The output signals of the first and second pressure sensors are connected to the flow controller (17), and the output signal of the flow controller is input to the proportional amplifier (18), which controls the output force of the proportional electromagnet; the flow controller includes a subtractor (19), an interpolation controller (20), and a digital flow compensation model (21); The proportional flow valve (4) is located at the P port and / or T port of the main directional valve. The proportional flow valve (4) includes a main valve sleeve, a main valve core, and a pilot valve. The main valve control chamber is connected to the first pressure sensor, and the main valve outlet is connected to the second pressure sensor. The signal output terminals of the first and second pressure sensors are connected to the flow controller. The output signal of the flow controller is input to the proportional amplifier, and the proportional amplifier is connected to and controls the proportional electromagnet. The proportional flow valve uses an interpolation flow control method, including the following steps: Step 1: Obtain the digital flow compensation model of the pilot valve through experimental or simulation methods; Step 2: Discretize the digital traffic compensation model and use... The values ​​are stored in the interpolation controller in the form of i = 1, 2, 3…n; j = 1, 2, 3…m; Step 3: Input the pressure signals pA and pB detected by the first pressure sensor and the second pressure sensor into the flow controller. Input the pilot valve port pressure difference Δp* obtained in real time through the subtractor into the interpolation controller. At the same time, input the desired flow rate qd into the interpolation controller. Step 4: Based on the interpolation principle A flow correction signal is generated, and the displacement of the pilot valve solenoid is compensated based on this flow correction signal.

2. The independent control valve for oil inlet and outlet according to claim 1, characterized in that: The proportional flow valve is further equipped with a pilot valve displacement sensor (22). The pilot valve displacement sensor is integrated on the proportional electromagnet and detects the displacement and speed of the pilot valve core by detecting the position of the proportional electromagnet core. Alternatively, it can be mounted on the pilot valve core through a shaft to directly detect the position and speed of the pilot valve core. The output signal of the flow controller and the output signal of the pilot valve displacement sensor are input to the pilot valve displacement controller (23). After the signal is processed by the proportional amplifier, it controls the proportional electromagnet to output force or displacement.

3. The independent control valve for oil inlet and outlet according to claim 1 or 2, characterized in that: The proportional flow valve further integrates pressure control functions and is equipped with a third pressure sensor (24), a pressure controller (25), and a control switch (26). The third pressure sensor is installed in the cavity connected to the oil inlet C1 of the proportional flow valve. The signal output terminals of the second and third pressure sensors are connected to the pressure controller. The output signals of the pressure controller and the flow controller are connected to the input terminal of the control switch (26). The output terminal of the control switch controls the proportional electromagnet through a proportional amplifier. By switching the position of the control switch, the proportional flow valve can be selected to perform pressure control or flow control.

4. The independent control valve for oil inlet and outlet according to claim 1, characterized in that: The main directional valve outlet T can also be set as the proportional flow valve, with the proportional flow valve inlet C1 connected to the main directional valve outlet T and the proportional flow valve outlet D1 connected to the oil tank.

5. An independent control valve for oil inlet and outlet as described in claim 1 or 4, characterized in that: The main directional valve is a closed-center multi-way directional valve with a load-sensitive detection port LS. Or an open-center multi-way directional valve with a neutral oil circuit; Or a three-position four-way proportional directional valve.

6. A valve for independent control of oil inlet and outlet ports according to claim 1 or 4, characterized in that: The main directional valve is one of the following: hydraulic control, electro-proportional direct control, and electro-hydraulic proportional control.

7. A load-sensitive system for independent control of oil inlet and outlet ports, characterized in that: It includes a power source (27), a load-sensitive hydraulic pump (28), a main safety valve (29), and at least two sets of control valves, wherein at least one set of control valves is an independent inlet and outlet control valve as described in claim 1; the power source and the load-sensitive hydraulic pump are coaxially mechanically connected, the outlet of the load-sensitive hydraulic pump is connected to the main safety valve and the main oil circuit (30), the inlets of each set of control valves share a unified main oil circuit, and the outlets are connected to a unified return oil circuit (31) and then connected to the oil tank; The independent control valves for the inlet and outlet oil ports are: The main directional valve is a closed-center multi-way directional valve with a load-sensitive detection port LS; the closed-center multi-way directional valve is equipped with a proportional flow valve at port P and a proportional relief valve at port T; the proportional flow valve inlet C1 is connected to the main oil circuit, and the proportional flow valve outlet D1 is connected to the closed-center multi-way directional valve inlet P; the proportional relief valve inlet is connected to the closed-center multi-way directional valve return port T, and the proportional relief valve outlet is connected to the return oil circuit. or The main directional valve is a closed-center multi-way directional valve with a load-sensitive detection port LS. A proportional flow valve is installed before the inlet port P of the closed-center multi-way directional valve. The inlet port C1 of the proportional flow valve is connected to the main oil circuit, and the outlet port D1 of the proportional flow valve is connected to the inlet port P of the closed-center multi-way directional valve. A proportional flow valve is added at the return port T of the closed-center multi-way directional valve. The inlet port of the proportional flow valve is connected to the return port T of the closed-center multi-way directional valve, and the outlet port of the proportional flow valve is connected to the oil tank.

8. A flow matching system for independent control of oil inlet and outlet ports, characterized in that: It includes a power source, a main hydraulic pump (42), a main safety valve, and at least two sets of control valves, wherein at least one set of control valves is an independent inlet and outlet control valve as described in claim 1; the power source and the hydraulic pump are mechanically connected coaxially, the outlet of the hydraulic pump is connected to the main safety valve and the main oil circuit, the inlet of each set of control valves shares a unified main oil circuit, and the outlet is connected to the oil tank through a unified return oil circuit; The power source mentioned is either an electric motor or a diesel engine; The main hydraulic pump is one of a fixed displacement pump and an electro-proportional variable displacement pump. The independent control valves for the inlet and outlet oil ports are as follows: The main directional valve is a three-position four-way proportional directional valve. A proportional flow valve is installed before the oil inlet P port of the three-position four-way proportional directional valve, and a proportional relief valve is installed at the T port. The oil inlet C1 of the proportional flow valve is connected to the main oil circuit, and the oil outlet D1 of the proportional flow valve is connected to the oil inlet P of the three-position four-way proportional directional valve. The oil inlet of the proportional relief valve is connected to the oil outlet T of the three-position four-way proportional directional valve, and the oil outlet of the proportional relief valve is connected to the oil tank. or The main directional valve is a three-position four-way proportional directional valve. A proportional flow valve is added before the oil inlet P of the three-position four-way proportional directional valve. The oil inlet C1 of the proportional flow valve is connected to the main oil circuit, and the oil outlet D1 of the proportional flow valve is connected to the oil inlet P of the three-position four-way proportional directional valve. A proportional flow valve is installed at the oil outlet T of the three-position four-way proportional directional valve. The oil inlet of the proportional flow valve is connected to the oil outlet T of the three-position four-way proportional directional valve, and the oil outlet of the proportional flow valve is connected to the oil tank.

9. A negative flow system with independent control of oil inlet and outlet, characterized in that: It includes a power source, a negative flow throttle port (40), a negative flow detection oil circuit (41), a negative flow control hydraulic pump (43), a main safety valve, and no less than two sets of control valves. At least one set of control valves is an independent inlet and outlet control valve as described in claim 1. The power source and the negative flow control hydraulic pump are coaxially mechanically connected. The outlet of the negative flow control hydraulic pump is connected to the main safety valve and the main oil circuit. The inlets of each set of control valves share a unified main oil circuit (30). The outlets are connected to the oil tank through a unified return oil circuit. The outlet F of the main directional valve's middle position oil circuit is connected to the negative flow throttle port and the negative flow detection oil circuit. The negative flow detection oil circuit is connected to the negative flow controller of the negative flow control hydraulic pump. The negative flow throttle port is connected to the oil tank. The independent control valves for the inlet and outlet oil ports are: The main directional valve is an open-center multi-way directional valve with a center position oil circuit. The inlet P of the open-center multi-way directional valve is equipped with a proportional flow valve, and the outlet T of the open-center multi-way directional valve is equipped with a proportional relief valve. The inlet C1 of the proportional flow valve is connected to the main oil circuit, and the outlet D1 of the proportional flow valve is connected to the inlet P of the open-center multi-way directional valve. The inlet of the proportional relief valve is connected to the outlet T of the open-center multi-way directional valve, and the outlet of the proportional relief valve is connected to the oil tank. or The main directional valve is an open-center multi-way directional valve with a center position oil circuit. A proportional flow valve is added before the oil inlet P of the open-center multi-way directional valve. The oil inlet C1 of the proportional flow valve is connected to the main oil circuit, and the oil outlet D1 of the proportional flow valve is connected to the oil inlet P of the three-position four-way proportional directional valve. A proportional flow valve is installed at the oil outlet T of the open-center multi-way directional valve. The oil inlet of the proportional flow valve is connected to the oil outlet T of the open-center multi-way directional valve, and the oil outlet of the proportional flow valve is connected to the oil tank.

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