Flow control system, work machine, and flow control method

Abstract

The present application relates to the field of hydraulic flow control, and provides a flow control system, a working machine and a flow control method, wherein the flow control system comprises: comparing the pressure of a first load sensing end with the pressure of a control end to control the unloading flow of a first unloading port; a second load sensing end applies the maximum load pressure of a working valve group to the first load sensing end; and a controller controls the flow output of an oil source module based on the detection result of an unloading flow detection module. The present application solves or improves the defect that the flow control cannot realize the composite action of multiple actuators in the prior art. The flow control system provided by the present application applies the maximum load pressure of the working valve group to the first load sensing end of the unloading module, compares the pressure of the first load sensing end with the pressure of the control end, controls the unloading flow of the first unloading port, and the controller regulates and controls the output flow of the oil source module based on the unloading flow to meet the flow demand of each actuator, so that the composite action performance is good.

Description

Technical Field

[0001] This invention relates to the field of hydraulic flow control technology, and in particular to a flow control system, a working machine, and a flow control method. Background Technology

[0002] Traditional construction machinery often uses internal combustion engines as its power system. The hydraulic system of this machinery is also powered by the internal combustion engine. Therefore, the flow rate of the hydraulic system cannot be adjusted by changing the engine speed; it can only be adjusted by regulating the system pressure and the pump displacement. In a hydraulic system composed of a gear pump and a manual throttle valve, the pump output flow rate is only related to the engine speed. To balance energy consumption and actuator speed requirements, a moderate pump displacement is selected, resulting in slow actuator speed at low speeds and high energy consumption at high speeds.

[0003] Currently, existing flow control hydraulic systems use an electric motor as the power source for the hydraulic pump. Damping is added to the return oil circuit of the actuator to monitor the return oil pressure and feed it back to the controller. The controller then controls the motor speed to adjust the pump output flow and meet the flow requirements of the hydraulic system. However, due to the complex operating conditions of construction machinery, the required flow of the actuator varies under different conditions. Directly using the required flow of the actuator as the target flow for control involves a large amount of target flow calibration work, and the control is complex and difficult. Furthermore, since construction machinery typically has multiple actuators operating simultaneously, flow control for multiple actuators with combined actions cannot be achieved, limiting its application scope. Summary of the Invention

[0004] This invention provides a flow control system, operating machinery, and flow control method to solve or improve the shortcomings of existing technologies in flow control that cannot achieve compound actions of multiple actuators. It realizes the comparison between the maximum load pressure fed back to the unloading module by the working valve and the pressure at the control end of the unloading module to output the unloading flow. The unloading flow is detected and the oil source module is controlled. The control process is simple and can realize flow regulation of compound actions of multiple actuators.

[0005] This invention provides a flow control system, comprising:

[0006] Oil source module;

[0007] The unloading module includes a first oil inlet, a first load-sensitive end, a control end, and a first unloading port. The first oil inlet is connected to the oil source module, and the control end is connected to the first oil inlet. The pressure of the control end is compared with the pressure of the first load-sensitive end to control the unloading flow rate of the first unloading port.

[0008] An unloading flow detection module is used to detect the unloading flow at the first unloading port.

[0009] The working valve assembly includes a second oil inlet and a second load-sensitive end. The second oil inlet is connected to the oil source module, and the second load-sensitive end is connected to the first load-sensitive end, so that the maximum load pressure of the working valve assembly is applied to the first load-sensitive end.

[0010] The controller is electrically connected to the unloading flow detection module and the oil source module respectively, so as to control the flow output of the oil source module according to the detection result of the unloading flow detection module.

[0011] According to the flow control system provided by the present invention, the working valve includes a return port, which is connected to the oil tank;

[0012] The first unloading port is connected to the oil tank.

[0013] According to the flow control system provided by the present invention, the unloading module includes a second unloading port, and the pressure at the control end is used to compare with the pressure at the first load-sensitive end to control the unloading flow rate of the second unloading port.

[0014] According to the flow control system provided by the present invention, the working valve assembly includes a comparator valve, a first working assembly, and a second working assembly, wherein the first working assembly and the second working assembly respectively control different actuators of the flow control system;

[0015] The load port of the first working link and the load port of the second working link are both connected to the comparator valve, and the comparator valve is connected to the second load sensitive end.

[0016] According to the flow control system provided by the present invention, the first working link includes a first main valve and a first load compensation valve, and the second working link includes a second main valve and a second load compensation valve. The first main valve is connected to the second oil inlet and the first load compensation valve respectively, and the second main valve is connected to the second oil inlet and the second load compensation valve respectively.

[0017] The first load compensation valve includes a third load sensitive terminal, which is connected to the second load sensitive terminal; the second load compensation valve includes a fourth load sensitive terminal, which is connected to the second load sensitive terminal.

[0018] The comparator valve includes a first shuttle valve, the first comparison port of which is connected to the first main valve, the second comparison port of which is connected to the second main valve, and the first comparison result port of which is connected to the second load-sensitive end; or, the comparator valve includes a first shuttle valve and a second shuttle valve, the first comparison port of which is connected to the first main valve, the third comparison port of which is connected to the second main valve, the fourth comparison port of which is blocked, the second comparison result port of which is connected to the second comparison port of which is connected to the first shuttle valve, and the first comparison result port of which is connected to the second load-sensitive end.

[0019] According to the flow control system provided by the present invention, the unloading flow detection module includes a damper and a pressure sensor. The damper is disposed between the oil tank of the flow control system and the first unloading port, and the pressure sensor is disposed between the damper and the first unloading port. The pressure sensor is used to detect the pressure of the first unloading port.

[0020] Wherein, the pressure sensor is electrically connected to the controller; and / or,

[0021] The oil source module includes a variable frequency motor and a metering pump. The variable frequency motor is connected to the metering pump and is electrically connected to the controller.

[0022] The present invention also provides a working machine, including the above-described flow control system.

[0023] The working machinery provided by the present invention further includes a hydraulic working circuit, which is connected between the oil source module and the unloading module;

[0024] The hydraulic working circuit is one of the steering circuit, braking circuit, and travel circuit.

[0025] The present invention also provides a flow control method for the above-mentioned flow control system, comprising:

[0026] The working valve linkage controls the operation of the actuator, and the working valve linkage obtains the maximum load pressure of the actuator;

[0027] The maximum load pressure is applied to the first load-sensitive end of the unloading module. The pressure at the first load-sensitive end is compared with the pressure at the control end of the unloading module to control the first unloading port of the unloading module to unload.

[0028] The unloading flow rate of the first unloading port is obtained, and the unloading flow rate is compared with a preset value to control the flow output of the oil source module so that the unloading flow rate is equal to the preset value.

[0029] The flow control method provided by the present invention further includes:

[0030] The actuator is in standby mode;

[0031] The maximum load pressure of the working valve is zero. The spring resistance of the first load-sensitive end of the unloading module is compared with the pressure of the control end of the unloading module to control the overflow of the first unloading port of the unloading module.

[0032] The unloading flow rate of the first unloading port is obtained, and the unloading flow rate is compared with a preset value to control the flow output of the oil source module so that the unloading flow rate is equal to the preset value.

[0033] The flow control system provided by this invention obtains the maximum load pressure through a working valve connection and applies the maximum load pressure to the first load-sensitive end of the unloading module. The pressure at the first load-sensitive end is compared with the pressure at the control end to control the unloading flow rate at the first unloading port. The unloading flow rate at the first unloading port is detected by the unloading flow rate module and sent to the controller. The controller adjusts the output flow rate of the oil source module based on the unloading flow rate to meet the flow requirements of each actuator. It has good composite action performance, simple control, high operating efficiency, and improved control accuracy.

[0034] Furthermore, the working machinery provided by the present invention possesses the flow control system described above, and therefore also possesses the various advantages described above; the flow control method provided by the present invention can be implemented through the flow control system described above, and therefore also possesses the various advantages described above. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in this invention 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 invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0036] Figure 1 This is one of the hydraulic schematic diagrams of the flow control system provided by the present invention;

[0037] Figure 2 This is the second hydraulic schematic diagram of the flow control system provided by the present invention;

[0038] Figure 3 This is a schematic diagram of the working principle of the flow control system provided by the present invention;

[0039] Figure 4 This is one of the hydraulic schematic diagrams of the operating machinery provided by the present invention;

[0040] Figure 5 This is the second hydraulic schematic diagram of the operating machinery provided by the present invention;

[0041] Figure 6 This is one of the flowcharts of the flow control method provided by the present invention;

[0042] Figure 7 This is the second flowchart of the flow control method provided by the present invention.

[0043] Figure label:

[0044] 100: Oil source module; 101: Metering pump; 102: Variable frequency motor; 103: Oil tank; 200: Unloading module; 201: First oil inlet; 202: First load-sensitive end; 203: First unloading port; 204: Second unloading port; 205: Control terminal; 300: Working valve connection; 301: Second oil inlet; 302: Second load-sensitive end; 303: Return oil port; 304: Comparison valve; 310: First working connection; 311: First main valve; 312: First load compensation valve; 313: Third load-sensitive end; 314: The... 320: Second working port; 321: Second main valve; 322: Second load compensation valve; 330: First shuttle valve; 331: First comparison port; 332: First comparison result port; 333: Second comparison port; 340: Second shuttle valve; 400: Unloading flow detection module; 401: Damping; 402: Pressure sensor; 500: Controller; 600: Actuator; 601: First cylinder; 700: Hydraulic working circuit; 701: Priority valve; 702: Steering system; 703: Filling valve; 704: Braking system. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0046] In the description of the embodiments of the present invention, it should be noted that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention 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. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0047] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0048] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0049] The following is combined Figures 1 to 7 The embodiments of the present invention will be described below. It should be understood that the following description is merely an illustrative embodiment of the present invention and does not constitute a limitation thereof.

[0050] like Figure 1As shown, the present invention provides a flow control system, including: an oil source module 100, an unloading module 200, an unloading flow detection module 400, a working valve assembly 300, and a controller 500. The unloading module 200 includes a first oil inlet 201, a first load-sensitive end 202, a control end 205, and a first unloading port 203. The first oil inlet 201 is connected to the oil source module 100, and the control end 205 is connected to the first oil inlet 201. The pressure of the control end 205 is compared with the pressure of the first load-sensitive end 202 to control the unloading flow of the first unloading port 203. The unloading flow detection module 400... The 00 is set at the first unloading port 203 to detect the unloading flow of the first unloading port 203; the working valve connection 300 includes a second oil inlet 301 and a second load sensitive end 302. The second oil inlet 301 is connected to the oil source module 100, and the second load sensitive end 302 is connected to the first load sensitive end 202 to apply the maximum load pressure of the working valve connection 300 to the first load sensitive end 202; the controller 500 is electrically connected to the unloading flow detection module 400 and the oil source module 100 respectively to control the flow output of the oil source module 100 according to the detection result of the unloading flow detection module 400.

[0051] In other words, the pressurized oil from the oil source module 100 simultaneously enters the first inlet 201 and the second inlet 301. The pressurized oil from the first inlet 201 is connected to the control terminal of the unloading module 200 as one of the comparison oil sources. The second inlet 301 enters the working valve coupling 300 to drive the load. The working valve coupling 300 feeds back the maximum load pressure to the first load sensitive terminal 202 as the second comparison oil source. The unloading module 200 compares the output pressure of the oil source module 100 with the load pressure, controls the opening of the valve core of the unloading module 200, and then feeds back the magnitude of the unloading flow rate at the first unloading port 203. The unloading flow detection module 400 detects the unloading flow rate at the first unloading port 203 and sends it to the controller 500. After processing, the controller 500 sends a command to the oil source module 100 to adjust the flow output of the oil source module 100 so that the output pressure of the oil source module 100 matches the load pressure.

[0052] In other words, the working valve 300 and the unloading module 200 are connected in parallel. The load pressure at the second load-sensitive end 302 of the working valve 300 changes with the load. The unloading module 200 converts the load change into a change in the unloading flow rate at the first unloading port 203. Based on the change in unloading flow rate, the output flow rate of the oil source module 100 is controlled until the unloading flow rate meets the preset conditions, forming a closed-loop control and improving control accuracy. The second load-sensitive end 302 obtains the maximum load pressure as a comparison oil source, and adjusts the output flow rate of the oil source module 100. This ensures that when multiple actuators 600 perform compound actions, each actuator 600 is in a state of saturated demand flow rate, resulting in good compound action performance and high operating efficiency.

[0053] Continue to refer to Figure 1 In one embodiment of the present invention, the working valve connection 300 includes an oil return port 303, which is connected to the oil tank 103 of the flow control system; wherein, the first unloading port 203 is connected to the oil tank 103.

[0054] In other words, the actuator 600 returns oil through the return oil port 303 of the working valve connection 300, which is independent of the unloading flow detection module 400 of the first unloading port 203 and does not affect each other. The return oil circuit of the actuator 600 has no damping 401, no back pressure, and low energy consumption.

[0055] like Figure 1 As shown, in a specific embodiment of the present invention, the unloading module 200 includes a second unloading port 204, and the pressure of the control end 205 is used to compare with the pressure of the first load sensitive end 202 to control the unloading flow rate of the second unloading port 204.

[0056] In other words, the oil pressure at the first inlet 201 acts on the control terminal 205 to compare the pressure at the control terminal 205 with that at the first load-sensitive terminal 202. For the unloading module 200 of this invention, the first load-sensitive terminal 202 includes a spring and a hydraulic control port, which is connected to the second load-sensitive terminal 302. The sum of the pressure at the second load-sensitive terminal 302 and the spring pressure is compared with the pressure at the control terminal 205, thus realizing three actions of the valve core of the unloading module 200. The unloading module 200 can be a three-position, three-way differential pressure relief valve.

[0057] When the pressure at the second load-sensitive end 302 is zero, i.e. in standby mode: the spring pressure is greater than the pressure at the control end 205. Because the initial output pressure of the oil source module 100 is relatively small, the first unloading port 203 has no unloading flow or a small unloading flow. The unloading flow detection module 400 feeds back the current unloading flow to the controller 500. If the unloading flow is less than the preset value, the controller 500 controls the oil source module 100 to increase its output flow until the pressure at the control end 205 is greater than the spring pressure and the unloading flow reaches the preset value, thus maintaining the output state of the oil source module 100.

[0058] When the pressure at the second load-sensitive end 302 increases, the actuator 600, which increases its operation, becomes more powerful. The sum of the pressure at the second load-sensitive end 302 and the spring pressure exceeds the pressure at the control end 205, causing the unloading module 200 to be in its first operating position. This means the first oil inlet 201 and the first unloading port 203 are closed, resulting in zero unloading flow. The controller 500 receives the detection result from the unloading flow detection module 400 and controls the oil source module 100 to increase its output flow, for example, by increasing the rotational speed of the oil source module 100. This continues until the pressure at the control end 205 exceeds the sum of the pressure at the second load-sensitive end 302 and the spring pressure, and the unloading flow reaches a preset value. For example, the unloading module 200 is in its second operating position, meaning the second unloading port 204 is closed, and the unloading flow at the first unloading port 203 reaches a preset value.

[0059] When the pressure at the second load-sensitive end 302 decreases from high to low, the actuator 600 reduces its operation: the sum of the pressure at the second load-sensitive end 302 and the spring pressure is less than the pressure at the control end 205, causing the unloading module 200 to be in the third operating position, i.e., the first oil inlet 201 is simultaneously connected to the first unloading port 203 and the second unloading port 204, and the second unloading port 204 achieves a large-flow overflow. The unloading flow rate of the first unloading port 203 increases, and the controller 500 receives the detection result from the unloading flow rate detection module 400, controlling the oil source module 100 to reduce the output flow rate, for example, by reducing the rotational speed of the oil source module 100. This continues until the unloading module 200 is in the second operating position, i.e., the second unloading port 204 is closed, and the unloading flow rate of the first unloading port 203 reaches a preset value.

[0060] For example, the unloading module 200 includes an inlet, a first unloading port 203, and a second unloading port 204. The inlet is connected to the first oil inlet 201, and the first unloading port 203 and the second unloading port 204 are respectively connected to the oil tank 103. In the first working position, the inlet, the first unloading port 203, and the second unloading port 204 are not connected to each other. In the second working position, the inlet is connected to the first unloading port 203, and the second unloading port 204 is blocked. In the third working position, the inlet is connected to both the first unloading port 203 and the second unloading port 204.

[0061] like Figure 2 As shown, in some embodiments of the present invention, the working valve link 300 includes a comparator valve 304, a first working link 310, and a second working link 320. The first working link 310 and the second working link 320 respectively control different actuators 600 of the flow control system. The load port of the first working link 310 and the load port of the second working link 320 are both connected to the comparator valve 304. The comparator valve 304 is connected to the second load sensitive end 302. The comparator valve 304 is used to obtain the maximum load pressure to the first load sensitive end 202.

[0062] Specifically, the first working link 310 controls the action of one actuator 600, and the second working link 320 controls the action of another actuator 600. Taking the first working link 310 as an example, the first working link 310 controls the direction and speed of the action of one actuator 600. The first working link 310 and the second working link 320 can work simultaneously or independently. Of course, other working links can also be included in the working valve link 300.

[0063] The comparator valve 304 can compare the load pressures of the first working link 310 and the second working link 320 to obtain the maximum load pressure, and then feed the maximum load pressure back to the first load-sensitive end 202; alternatively, it can compare the load pressures sequentially when there are multiple working links to obtain the maximum load pressure. The proportional valve can be electrically controlled to compare and output the maximum load pressure, or it can be hydraulically controlled to compare.

[0064] Further reference Figure 2 In other embodiments of the present invention, the first working link 310 includes a first main valve 311 and a first load compensation valve 312, and the comparison valve 304 includes a first shuttle valve 330. The first main valve 311 is connected to the second oil inlet 301, the first load compensation valve 312, and the first comparison port 331 of the first shuttle valve 330. The second comparison port 333 of the first shuttle valve 330 is connected to other shuttle valves of the comparison valve 304. Alternatively, the second working link 320 includes a second main valve 321 and a second load compensation valve 322. The second comparison port 333 of the first shuttle valve 330 can also be connected to the second main valve 321. The first comparison result port 332 of the first shuttle valve 330 is connected to the second load sensitive end 302. The first load compensation valve 312 includes a third load sensitive end 313, and the third load sensitive end 313 is connected to the second load sensitive end 302.

[0065] For example, an actuator 600 may be a first hydraulic cylinder 601. A first main valve 311 includes a left working position, a right working position, and a neutral position. Initially, the first main valve 311 is in the neutral position, at which point the first load compensation valve 312 is not operating. When the first main valve 311 is in the left working position, oil enters the rodless chamber of the first hydraulic cylinder 601. At this time, the first load compensation valve 312 operates, and the first load port 314 of the first main valve 311 is connected to the first comparison port 331 of the first shuttle valve 330. The first load port 314 communicates with the rodless chamber, and it feeds back the load pressure of the rodless chamber to the first comparison port 331. The pressures at the first comparison port 331 and the second comparison port 333 are compared. The pressure with the higher pressure flows out from the first comparison result port 332, which is connected to the second load sensitive end 302. Simultaneously, the third load sensitive end 313 of the first load compensation valve 312 is connected to the second load sensitive end 302.

[0066] Similarly, in another embodiment of the present invention, the second working link 320 includes a second main valve 321 and a second load compensation valve 322, and the comparison valve 304 includes a second shuttle valve 340. The second main valve 321 is connected to the second oil inlet 301, the second load compensation valve 322, and the third comparison port of the second shuttle valve 340, respectively. The fourth comparison port of the second shuttle valve 340 is connected to or blocked by other shuttle valves of the comparison valve 304. The second comparison result port of the second shuttle valve 340 is connected to the second comparison port 333 of the first shuttle valve 330. The second load compensation valve 322 includes a fourth load sensitive end, which is connected to the second load sensitive end 302. The first comparison port 331 of the first shuttle valve 330 is connected to the first main valve 331, and the first comparison result port 332 of the first shuttle valve 330 is connected to the second load sensitive end 302. In other words, the structure of the second working link 320 is the same as that of the first working link 310. The first working link 310 and the second working link 320 compare pressures through the first shuttle valve 330 and the second shuttle valve 340. The maximum load pressure after comparison is output to the second load sensitive end 302 through the first shuttle valve 330.

[0067] Since the first shuttle valve 330 feeds back the maximum load of the actuator 600 to the first load compensation valve 312 and the second load compensation valve 322, the pressure of the load compensation valves of each working link is the same. In addition, each working link is connected to the second oil inlet 301, so the oil inlet pressure is the same. Therefore, the pressure difference before and after each main valve is the same. The flow rate through the main valve is only linearly related to the opening degree of the main valve, resulting in high control accuracy.

[0068] Taking the first working link 310 as an example, the first load compensation valve 312 can be either upstream or downstream compensation, such as... Figure 3 As shown, taking post-valve compensation as an example, the first main valve 311 includes ports P, B, A, C, D, and T, and a first load port 314. Port P is connected to the second oil inlet 301, port B is connected to the rod chamber of the cylinder, port A is connected to the rodless chamber, port C is connected to port D, port T is connected to the oil tank 103, and the first load port 314 is connected to the first shuttle valve 330. When the first main valve 311 is in the left working position, port P is connected to port C, port B is connected to port T, port A is connected to port D, and the first load port 314 is connected to port A. When the first main valve 311 is in the right working position, port P is connected to port C, port B is connected to port D, port A is connected to port T, and the first load port 314 is connected to port B.

[0069] In other words, the pressure difference between the P port and the C port of each main valve is equal, and the flow rate through the main valve is only linearly related to the opening degree of the main valve, resulting in high control accuracy.

[0070] Continue to refer to Figure 1In other embodiments of the present invention, the unloading flow detection module 400 includes a damper 401 and a pressure sensor 402. The damper 401 is disposed between the oil tank 103 of the flow control system and the first unloading port 203, and the pressure sensor 402 is disposed between the damper 401 and the first unloading port 203. The pressure sensor 402 is used to detect the pressure of the first unloading port 203. The pressure sensor 402 is electrically connected to the controller 500. The controller 500 converts the pressure value of the pressure sensor 402 into a flow rate value, and then compares it with a preset flow rate.

[0071] Furthermore, to improve control accuracy, a temperature sensor can be installed at the first unloading port 203. The controller 500 uses the oil temperature reading from the temperature sensor to control the oil source module 100. In other words, the damper 401 is a thin-walled orifice. The oil flow rate through this orifice is only related to the orifice diameter and pressure difference. With a fixed orifice diameter, the flow rate can be monitored by the pressure difference. If necessary, a temperature sensor can be added to monitor the oil temperature, correcting the influence of oil temperature on the flow rate and further improving monitoring accuracy.

[0072] Alternatively, the unloading flow detection module 400 can use a flow sensor to directly obtain the flow value and feed it back to the controller 500.

[0073] In addition, in some optional embodiments of the present invention, the oil source module 100 includes a variable frequency motor 102 and a metering pump 101, the variable frequency motor 102 is connected to the metering pump 101, and the variable frequency motor 102 is electrically connected to the controller 500.

[0074] Specifically, the variable frequency motor 102 is mechanically connected to the fixed displacement pump 101, driving the fixed displacement pump 101 to rotate and provide a pressure oil source for the hydraulic system. The variable frequency motor 102 is electrically connected to the controller 500, which adjusts the speed of the variable frequency motor 102 according to the control signal and adjusts the output flow of the fixed displacement pump 101 to meet the flow requirements of the hydraulic system. The power supply of the variable frequency motor 102 can be a storage battery or a power battery, depending on the usage requirements.

[0075] The fixed displacement pump 101 can be a gear pump, vane pump, fixed displacement piston pump, etc.; the actuator 600 can be a hydraulic cylinder, motor, etc.; the controller 500 can be integrated into the vehicle controller 500 or a separate controller 500 can be used. The first working link 310 and the second working link 320 can be manually controlled or electrically controlled. The electrical control can be electrically connected to the controller 500 to realize the main valve opening control.

[0076] The present invention also provides a working machine, including the flow control system of the above embodiments. For example, the working machine can be construction machinery such as cranes, excavators, pile drivers, graders, etc., or engineering vehicles such as aerial work platforms, fire trucks, cement mixers, etc.

[0077] In addition, such as Figure 4 and Figure 5 As shown, in some optional embodiments of the present invention, the working machinery further includes a hydraulic working circuit 700, which is connected between the oil source module 100 and the unloading module 200. The hydraulic working circuit 700 is one of a steering circuit, a braking circuit, or a travel circuit. For example, when the hydraulic working circuit 700 is a steering circuit, the oil source module 100 is connected to the steering system 702 via a priority valve 701, and the unloading module 200 is connected to the priority valve 701. When the hydraulic working circuit 700 is a braking circuit, the oil source module 100 is connected to the braking system 704 via a filling valve 703, and the unloading module 200 is connected to the filling valve 703. That is, even when the oil source module 100 is connected to other working circuits, it can still adjust the oil source module 100 by feeding back the unloading flow rate through the unloading module 200, thereby achieving the flow rate required by other working circuits and the actuator 600.

[0078] like Figure 6 As shown, the present invention also provides a flow control method for a flow control system based on the above embodiments, comprising:

[0079] S1: The working valve link 300 controls the action of the actuator 600. The working valve link 300 obtains the maximum load pressure of the actuator 600. The working valve link 300 includes multiple working links, each of which controls a different actuator 600. The multiple actuators 600 can work simultaneously or individually. The working valve link 300 compares the load pressures of the multiple actuators 600 and outputs the maximum load pressure among the actuators 600.

[0080] S2: The maximum load pressure acts on the first load-sensitive end 202 of the unloading module 200. The pressure at the first load-sensitive end 202 is compared with the pressure at the control end 205 of the unloading module 200 to control the unloading at the first unloading port 203 of the unloading module 200. That is, the unloading flow rate of the first unloading port of the unloading module 200 is obtained by comparing the maximum load pressure with the output pressure of the oil source module 100. The pressure at the first load-sensitive end 202 of the unloading module 200 changes with the maximum load pressure. The valve core action of the unloading module 200 is based on the comparison result between the first load-sensitive end 202 and the inlet oil pressure of the unloading module 200, and the unloading flow rate of the first unloading port 203 is based on the valve core action.

[0081] S3: Obtain the unloading flow rate of the first unloading port 203, compare the unloading flow rate with a preset value to control the flow output of the oil source module 100, that is, control the oil inlet pressure of the unloading module 200, so that the unloading flow rate equals the preset value. After the maximum load pressure increases, the unloading flow rate decreases, and the unloading flow rate is less than the preset value. The controller 500 controls the oil source module 100 to increase the flow output until the unloading flow rate equals the preset value. After the maximum load pressure decreases, the unloading flow rate increases, and the unloading flow rate is greater than the preset value. The controller 500 controls the oil source module 100 to decrease the flow output until the unloading flow rate equals the preset value.

[0082] The flow control method of this invention can set two or more preset values. The preset values ​​can be small, resulting in a small unloading flow and a small total flow, leading to the lowest overall energy consumption and forming an energy-saving control mode. The preset values ​​can also be large; when the operator sharply presses the manual control terminal 205 of the main valve, the large unloading flow quickly meets the needs of rapid operation, resulting in a fast response and forming a motion control mode. Finally, the preset values ​​can be large; in low-temperature conditions, the oil viscosity is high, and the response is slow, but the large unloading flow quickly meets the operation needs under low-temperature conditions, forming a low-temperature control mode. These three control modes are the basic control modes; other different control modes can be used depending on the usage characteristics of different engineering machinery.

[0083] Furthermore, in another embodiment of the invention, such as Figure 7 As shown, the flow control method also includes:

[0084] S10: The actuator 600 is in standby mode; that is, the actuator 600 is not working.

[0085] S11: When the maximum load pressure of the working valve 300 is zero, the spring resistance of the first load-sensitive end 202 of the unloading module 200 is compared with the pressure of the control end 205 of the unloading module 200 to control the overflow of the first unloading port 203 of the unloading module 200.

[0086] S12: Obtain the unloading flow rate of the first unloading port 203, compare the unloading flow rate with the preset value, and control the flow output of the oil source module 100, that is, control the oil inlet pressure of the unloading module 200 so that the unloading flow rate is equal to the preset value.

[0087] For example, the flow control method of the present invention can be implemented using the flow control system described in the above embodiments.

[0088] The flow control system provided by this invention obtains the maximum load pressure through the working valve connection 300 and applies the maximum load pressure to the first load sensitive end 202 of the unloading module 200. The pressure of the first load sensitive end 202 is compared with that of the control end 205 to control the unloading flow of the first unloading port 203. The unloading flow is detected by the unloading flow module and sent to the controller 500. The controller 500 adjusts the output flow of the oil source module 100 based on the unloading flow to meet the flow requirements of each actuator 600. It has good composite action performance, simple control, high operating efficiency, and improved control accuracy.

[0089] The present invention also provides a controller, including a processor and a memory, wherein the memory is used to store a computer program, and the processor is used to call and run the computer program from the memory, causing the computing node to perform the flow control method of the above embodiments.

[0090] The present invention also provides a computer-readable medium storing program code that, when run on a computer, causes the computer to perform the flow control method of the above embodiments.

[0091] Furthermore, the working machinery provided by the present invention possesses the flow control system described above, and therefore also possesses the various advantages described above; the flow control method provided by the present invention can be implemented through the flow control system described above, and therefore also possesses the various advantages described above.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention 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 of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A flow control system, characterized in that, include: Oil source module; The unloading module includes a first oil inlet, a first load-sensitive end, a control end, and a first unloading port. The first oil inlet is connected to the oil source module, and the control end is connected to the first oil inlet. The pressure of the control end is compared with the pressure of the first load-sensitive end to control the unloading flow rate of the first unloading port. The unloading flow detection module is used to detect the unloading flow of the first unloading port; The working valve assembly includes a second oil inlet and a second load-sensitive end. The second oil inlet is connected to the oil source module, and the second load-sensitive end is connected to the first load-sensitive end, so that the maximum load pressure of the working valve assembly is applied to the first load-sensitive end. The controller is electrically connected to the unloading flow detection module and the oil source module respectively, so as to control the flow output of the oil source module according to the detection result of the unloading flow detection module.

2. The flow control system according to claim 1, characterized in that, The working valve assembly includes an oil return port, which is connected to the oil tank. The first unloading port is connected to the oil tank.

3. The flow control system according to claim 1, characterized in that, The unloading module includes a second unloading port, and the pressure at the control end is compared with the pressure at the first load-sensitive end to control the unloading flow rate of the second unloading port.

4. The flow control system according to claim 1, characterized in that, The working valve assembly includes a comparator valve, a first working assembly, and a second working assembly, wherein the first working assembly and the second working assembly respectively control different actuators of the flow control system. The load port of the first working link and the load port of the second working link are both connected to the comparator valve, and the comparator valve is connected to the second load sensitive end.

5. The flow control system according to claim 4, characterized in that, The first working link includes a first main valve and a first load compensation valve, and the second working link includes a second main valve and a second load compensation valve. The first main valve is connected to the second oil inlet and the first load compensation valve, respectively, and the second main valve is connected to the second oil inlet and the second load compensation valve, respectively. The first load compensation valve includes a third load sensitive terminal, which is connected to the second load sensitive terminal; the second load compensation valve includes a fourth load sensitive terminal, which is connected to the second load sensitive terminal. The comparator valve includes a first shuttle valve, the first comparison port of which is connected to the first main valve, the second comparison port of which is connected to the second main valve, and the first comparison result port of which is connected to the second load-sensitive end; or, the comparator valve includes a first shuttle valve and a second shuttle valve, the first comparison port of which is connected to the first main valve, the third comparison port of which is connected to the second main valve, the fourth comparison port of which is blocked, the second comparison result port of which is connected to the second comparison port of which is connected to the first shuttle valve, and the first comparison result port of which is connected to the second load-sensitive end.

6. The flow control system according to any one of claims 1 to 5, characterized in that, The unloading flow detection module includes a damper and a pressure sensor. The damper is disposed between the oil tank of the flow control system and the first unloading port, and the pressure sensor is disposed between the damper and the first unloading port. The pressure sensor is used to detect the pressure at the first unloading port; wherein, the pressure sensor is electrically connected to the controller; and / or, The oil source module includes a variable frequency motor and a metering pump. The variable frequency motor is connected to the metering pump and is electrically connected to the controller.

7. A type of operating machinery, characterized in that, The flow control system includes any one of claims 1 to 6.

8. The operating machinery according to claim 7, characterized in that, It also includes a hydraulic working circuit, which is connected between the oil source module and the unloading module; The hydraulic working circuit is one of the steering circuit, braking circuit, and travel circuit.

9. A flow control method for a flow control system according to any one of claims 1 to 6, characterized in that, include: The working valve linkage controls the operation of the actuator, and the working valve linkage obtains the maximum load pressure of the actuator; The maximum load pressure is applied to the first load-sensitive end of the unloading module. The pressure at the first load-sensitive end is compared with the pressure at the control end of the unloading module to control the first unloading port of the unloading module to unload. The unloading flow rate of the first unloading port is obtained, and the unloading flow rate is compared with a preset value to control the flow output of the oil source module so that the unloading flow rate is equal to the preset value.

10. The flow control method according to claim 9, characterized in that, Also includes: The actuator is in standby mode; The maximum load pressure of the working valve is zero. The spring resistance of the first load-sensitive end of the unloading module is compared with the pressure of the control end of the unloading module to control the overflow of the first unloading port of the unloading module. The unloading flow rate of the first unloading port is obtained, and the unloading flow rate is compared with a preset value to control the flow output of the oil source module so that the unloading flow rate is equal to the preset value.

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