Anti-overflow system, work machine and Anti-overflow method

Abstract

The present application relates to the technical field of work machines. Disclosed are an anti-overflow system, a work machine and an anti-overflow method. The anti-overflow system comprises an actuation cylinder, a power pump, an overflow valve, a position sensor and a control module, wherein the actuation cylinder is adapted to extend or retract to execute a work action; an output end of the power pump is in communication with the actuation cylinder; an inlet end of the overflow valve is in communication with the output end of the power pump; the position sensor is adapted to detect the extension or retraction position of the actuation cylinder; and the control module is in communication connection with the power pump and the position sensor, and the control module is adapted to control, when it is determined that the actuation cylinder extends or retracts to a preset position, the power pump to gradually decrease the rotational speed at a preset acceleration so as to reduce the output flow rate, until the output flow rate of the power pump is reduced to a preset flow rate when the actuation cylinder extends and retracts to a limit position, under the condition of the preset flow rate, the pressure at the output end of the power pump being smaller than the opening pressure of the overflow valve.

Description

Anti-overflow system, working machine and anti-overflow method

[0001] The present application claims priority to the Chinese patent application No. 202411071673.6, filed on August 6, 2024, entitled "Anti-overflow system, working machine and anti-overflow method", the whole content of which is incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the technical field of working machines, in particular to an anti-overflow system, a working machine and an anti-overflow method. BACKGROUND

[0003] Working machines are widely used in various fields, such as machine tools, cranes, excavators, loaders, etc. In various working machines, hydraulic systems are widely used. The hydraulic (pneumatic) system includes a power pump, a hydraulic valve (pneumatic valve) and an actuator cylinder, etc. The power pump is connected with the actuator cylinder through the hydraulic valve, so that the power pump can provide power to drive the actuator cylinder to extend and retract to realize the working action. In order to prevent excessive pressure, an overflow valve is often arranged in the hydraulic system. When the pressure of the overflow valve is greater than the overflow pressure, the overflow valve will automatically open to let the excess liquid or gas flow out from the overflow port, so that the pressure in the hydraulic (pneumatic) system is kept below the overflow pressure to maintain the stability of the system.

[0004] However, the overflow valve is prone to jam during the overflow process, and once jammed, the whole machine cannot work. Moreover, the overflow valve has an overflow loss during work, i.e. part of the energy is dissipated in the form of heat energy during the overflow process, which cannot be effectively utilized by the system.

[0005] SUMMARY

[0006] Therefore, the present application provides an anti-overflow system, a working machine and an anti-overflow method to solve the problems of large jam probability and large overflow loss of the overflow valve of the working machine.

[0007] In a first aspect, the present application provides an anti-overflow system, comprising:

[0008] an actuator cylinder adapted to extend and retract to perform a working action;

[0009] a power pump having an output end connected with the actuator cylinder, the power pump being adapted to drive the actuator cylinder to extend and retract;

[0010] an overflow valve having an inlet end connected with the output end of the power pump;

[0011] a position sensor adapted to detect the extension and retraction position of the actuator cylinder;

[0012] A control module is in communication with the power pump and the position sensor, and is adapted to determine, when the actuator cylinder extends or retracts to a preset position, to control the power pump to gradually reduce the rotation speed at a preset acceleration to reduce the output flow, until the actuator cylinder extends or retracts to a limit position, the output flow of the power pump is reduced to a preset flow; wherein, under the condition of the preset flow, the pressure at the output end of the power pump is less than the opening pressure of the overflow valve.

[0013] When the actuator cylinder starts to extend or retract from an initial position to a limit position, the pressure at the output end of the power pump gradually increases. When the position sensor detects that the actuator cylinder extends or retracts to a preset position, a signal is sent to the control module, so that the control module determines that the actuator cylinder extends or retracts to the preset position. The control module immediately controls the power pump to gradually reduce the rotation speed at a preset acceleration to reduce the output flow. In this way, during the process that the actuator cylinder extends or retracts from the preset position to the limit position, the output flow of the power pump gradually reduces, and the pressure at the output end of the power pump increases at a small trend. When the actuator cylinder extends or retracts to the limit position, the output flow of the power pump is reduced to a preset flow, which is only used to balance the small flow caused by internal leakage and the like. When the output flow of the power pump is output at the preset flow, the pressure at the output end of the power pump increases to a value less than the opening pressure of the overflow valve, so as to maintain the actuator cylinder at the limit position. Therefore, it is ensured that the overflow valve does not overflow during the process, and the overflow valve is prevented from being stuck and causing overflow loss.

[0014] In an alternative embodiment, the anti-overflow system further comprises:

[0015] A pressure sensor is in communication with the control module, and is adapted to detect the pressure at the inlet end of the overflow valve, wherein:

[0016] The control module is adapted to determine, when the pressure at the inlet end of the overflow valve is less than the opening pressure of the overflow valve, and the actuator cylinder extends or retracts to a preset position, to control the power pump to gradually reduce the rotation speed at a preset acceleration to reduce the output flow, until the actuator cylinder extends or retracts to a limit position, the output flow of the power pump is reduced to a preset flow;

[0017] The control module is further adapted to determine, when the pressure at the inlet end of the overflow valve is not less than the opening pressure of the overflow valve, to control the power pump to reduce the rotation speed to reduce the output flow, so that the pressure at the inlet end of the overflow valve is less than the opening pressure of the overflow valve.

[0018] When the control module determines that the pressure at the inlet end of the overflow valve is not less than the opening pressure of the overflow valve, the control module controls the power pump to reduce the rotation speed and thus the output flow rate, so that the pressure at the inlet end of the overflow valve is reduced to be less than the opening pressure of the overflow valve, thereby ending the overflow of the overflow valve as soon as possible, reducing the overflow time of the overflow valve, and avoiding the increase of the probability of jamming and the increase of the overflow loss due to the long overflow time of the overflow valve.

[0019] In an optional embodiment, the anti-overflow system further comprises:

[0020] A pressure relief flow path is in communication with the output end of the power pump, and the pressure relief flow path is provided with an electromagnetic valve. The control module is in communication connection with the electromagnetic valve, and the control module is adapted to, when the pressure at the inlet end of the overflow valve does not change or continues to increase after the control module controls the power pump to reduce the rotation speed and thus the output flow rate under the condition that the pressure at the inlet end of the overflow valve is not less than the opening pressure of the overflow valve, control the power pump to relieve pressure.

[0021] When the control module determines that the pressure at the inlet end of the overflow valve is not less than the opening pressure of the overflow valve and controls the power pump to reduce the output flow rate, and the pressure at the inlet end of the overflow valve does not change or continues to increase, the control module controls the electromagnetic valve to open. Part of the output flow rate of the power pump is discharged through the pressure relief flow path to reduce the pressure at the output end of the power pump to be less than the opening pressure of the overflow valve, thereby ending the overflow of the overflow valve as soon as possible, reducing the overflow time of the overflow valve, and avoiding the increase of the probability of jamming and the increase of the overflow loss due to the long overflow time of the overflow valve.

[0022] In an optional embodiment, the anti-overflow system further comprises:

[0023] A one-way valve is in communication with the output end of the power pump and the actuator cylinder. The one-way valve is adapted to be one-way conductive when the power pump outputs flow rate to the actuator cylinder.

[0024] The one-way valve prevents the oil from flowing back to the hydraulic pump.

[0025] In an optional embodiment, a plurality of actuator cylinders are provided and are in communication with the power pump respectively, and a plurality of position sensors are provided and are in communication connection with the control module respectively. Each position sensor is adapted to detect the extension and retraction position of one actuator cylinder.

[0026] The corresponding position sensor detects the position of the different actuator cylinders, so that the control module can control the output flow rate of the power pump corresponding to different actuator cylinders, thereby avoiding the overflow of the overflow valve.

[0027] In a second aspect, the application further provides a working machine provided with a hydraulic system, wherein the hydraulic system comprises any of the anti-overflow systems described above.

[0028] The work machine has the same advantages as the anti-overflow system, and thus will not be described again.

[0029] In a third aspect, the application further provides an anti-overflow method. A power pump is in communication with an actuating cylinder. The power pump is adapted to drive the actuating cylinder to extend or retract to perform a work action. An overflow valve is in communication with the power pump. The anti-overflow method comprises:

[0030] When it is determined that the actuating cylinder retracts to a preset position, the power pump is controlled to gradually reduce the rotation speed at a preset acceleration to reduce the output flow rate, until the actuating cylinder retracts to a limit position, the output flow rate of the power pump is reduced to a preset flow rate; wherein, under the condition of the preset flow rate, the pressure at the output end of the power pump is less than the opening pressure of the overflow valve.

[0031] When it is determined that the actuating cylinder retracts to a preset position, the power pump is controlled to gradually reduce the rotation speed at a preset acceleration to reduce the output flow rate. In this way, during the process of the actuating cylinder retracting from the preset position to the limit position, the output flow rate of the power pump is gradually reduced, and the pressure at the output end of the power pump increases at a smaller trend. When the actuating cylinder retracts to the limit position, the output flow rate of the power pump is reduced to a preset flow rate, which is only used to balance the small flow rate of internal leakage and the like. When the output flow rate of the power pump is the preset flow rate, the pressure at the output end of the power pump is increased to a value less than the opening pressure of the overflow valve to maintain the actuating cylinder at the limit position. Thus, it is ensured that the overflow valve will not overflow during this process, and the overflow valve will not be stuck and the overflow loss will be avoided.

[0032] In an alternative embodiment, the anti-overflow method comprises:

[0033] When it is determined that the pressure at the inlet end of the overflow valve is less than the opening pressure of the overflow valve, and the actuating cylinder retracts to a preset position, the power pump is controlled to gradually reduce the rotation speed at a preset acceleration to reduce the output flow rate, until the actuating cylinder retracts to a limit position, the output flow rate of the power pump is reduced to a preset flow rate;

[0034] When it is determined that the pressure at the inlet end of the overflow valve is not less than the opening pressure of the overflow valve, the rotation speed of the power pump is controlled to reduce the output flow rate, so that the pressure at the inlet end of the overflow valve is less than the overflow pressure.

[0035] When it is determined that the pressure at the inlet end of the overflow valve is not less than the opening pressure of the overflow valve and the output flow rate of the power pump is reduced, and the pressure at the inlet end of the overflow valve does not change or continues to increase, the electromagnetic valve is controlled to be opened. Part of the flow rate output by the power pump is discharged through the pressure relief flow path to reduce the pressure at the output end of the power pump to less than the opening pressure of the overflow valve, so as to end the overflow of the overflow valve as soon as possible, reduce the overflow time of the overflow valve, and avoid the increase of the probability of the overflow valve being stuck and the increase of the overflow loss due to the long overflow time of the overflow valve.

[0036] In an alternative embodiment, the method further comprises, when the pressure at the inlet of the relief valve is not less than the opening pressure of the relief valve, controlling the power pump to reduce the output flow rate to reduce the pressure at the outlet of the power pump.

[0037] When the pressure at the inlet of the relief valve is not changed or continues to increase, controlling the power pump to release pressure.

[0038] When the pressure at the inlet of the relief valve is not less than the opening pressure of the relief valve and the output flow rate of the power pump is reduced, and the pressure at the inlet of the relief valve is not changed or continues to increase, releasing pressure at the outlet of the power pump to end the relief of the relief valve as soon as possible, reduce the relief time of the relief valve, and avoid increasing the probability of sticking and increasing the relief loss due to long relief time of the relief valve.

[0039] In an alternative embodiment, the method further comprises:

[0040] When the actuator is extended from the initial position to the limit position, and the actuator is extended to the working position, controlling the power pump to reduce the output flow rate to reduce the pressure at the outlet of the power pump, so that the extension position of the actuator is the working position when the pressure at the inlet of the relief valve is greater than the opening pressure of the relief valve.

[0041] When the actuator is extended to the working position, controlling the power pump to reduce the output flow rate to slow down the increasing speed of the pressure at the outlet of the power pump, so that the pressure at the outlet of the power pump cannot increase to exceed the opening pressure of the relief valve, or the pressure at the outlet of the power pump exceeds the opening pressure of the relief valve for a short time and then decreases to be lower than the opening pressure of the relief valve, thereby ending the relief of the relief valve as soon as possible, reducing the relief time of the relief valve, and avoiding increasing the probability of sticking and increasing the relief loss due to long relief time of the relief valve. BRIEF DESCRIPTION OF DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the specific embodiments or prior art of the present application, the drawings needed in the specific embodiments or prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0043] Fig. 1 is a schematic diagram of a relief prevention system according to an embodiment of the present application;

[0044] Fig. 2 is a flowchart of a relief prevention method according to an embodiment of the present application;

[0045] Fig. 3 is a diagram of the relationship between the pressure P at the inlet of the overflow valve and the extension stroke L of the actuator cylinder in the anti-overflow method of the embodiment of the present application;

[0046] Fig. 4 is a diagram of the relationship between the output flow rate Q of the power pump and the pressure P at the inlet of the overflow valve in the anti-overflow method of the embodiment of the present application;

[0047] Fig. 5 is a flowchart of another anti-overflow method of the embodiment of the present application;

[0048] Fig. 6 is a diagram of the relationship between the pressure P at the inlet of the overflow valve and the extension stroke L of the actuator cylinder in another anti-overflow method of the embodiment of the present application.

[0049] Reference Signs: 1, power pump; 2, actuator cylinder; 3, overflow valve; 4, position sensor; 5, pressure sensor; 6, electromagnetic valve; 7, check valve; 8, directional valve; 9, oil tank. DETAILED DESCRIPTION

[0050] To make the objectives, technical solutions, and superiorities of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described below in connection with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort belong to the scope of the present application.

[0051] The embodiments of the present application will be described below in connection with Figs. 1 to 6.

[0052] According to the embodiments of the present application, in one aspect, as shown in Fig. 1, an anti-overflow system is provided and applied in a loader. The anti-overflow system comprises an actuator cylinder 2, a power pump 1, an overflow valve 3, a position sensor 4, and a control module. The actuator cylinder 2 is a hydraulic cylinder, and the power pump 1 is a hydraulic pump. The output end of the power pump 1 is connected to the inlet of the electromagnetic directional valve 8 through a pipeline and then connected to the inlet of the actuator cylinder 2, and the outlet of the actuator cylinder 2 is connected to the outlet of the electromagnetic directional valve 8 through a pipeline and then connected to the oil tank 9. Thus, the power pump 1 outputs oil and drives the actuator cylinder 2 to extend and retract between an initial position and a limit position Lmax and perform a work action through the electromagnetic directional valve 8, wherein the work action can be a lifting action and a dumping action. The inlet of the overflow valve 3 is connected to the output end of the power pump 1 through a pipeline, and the outlet of the overflow valve 3 is connected to the oil tank 9 through a pipeline. The pressure at the output end of the power pump 1 is the same as the pressure at the inlet of the overflow valve 3. When the pressure at the output end of the power pump 1 is greater than the opening pressure of the overflow valve 3, the overflow valve 3 opens and overflows the excess flow rate at the output end of the power pump 1 to the oil tank 9, so as to control the pressure at the output end of the power pump 1 to be less than or equal to the opening pressure of the overflow valve 3.

[0053] When the cylinder 2 is extended or retracted and the working action is performed, the position sensor 4 detects the extension or retraction position of the cylinder 2 in real time, i.e. where the cylinder 2 extends or retracts at a certain moment. The control module is communicatively connected with the power pump 1 and the position sensor 4, and can control the power pump 1 to reduce the rotation speed and thus reduce the output flow. After the position sensor 4 detects the extension or retraction position of the cylinder 2, it can send a signal containing the position information of the cylinder 2 to the control module.

[0054] As shown in FIGS. 2, 3 and 4, a preset position Lb is provided between the initial position and the limit position Lmax. When the cylinder 2 is at the initial position, the extension or retraction amount of the cylinder 2 is 0, and the pressure at the output end of the power pump 1 is 0. When the power pump 1 starts to output the flow Qe, the cylinder 2 starts to extend or retract from the initial position to the limit position Lmax, and the pressure at the output end of the power pump 1 gradually increases. The position sensor 4 detects the extension or retraction position of the cylinder 2 in real time, and when the position sensor 4 detects that the cylinder 2 extends or retracts to the preset position Lb, it sends a signal to the control module, so that the control module determines that the cylinder 2 extends or retracts to the preset position Lb. The control module immediately sends a control signal to the power pump 1 to control the power pump 1 to gradually reduce the rotation speed and thus reduce the output flow at a preset acceleration. In this way, during the extension or retraction of the cylinder 2 from the preset position to the limit position Lmax, the output flow Q of the power pump 1 gradually decreases, and the pressure P at the output end of the power pump 1 increases at a smaller rate. When the cylinder 2 extends or retracts to the limit position Lmax, the pressure P at the output end of the power pump 1 increases to Pc, the output flow of the power pump 1 decreases to a preset flow Q0, and as the power pump 1 continues to output the flow, the pressure P at the output end of the power pump 1 no longer increases after increasing to the working pressure Pd. The preset flow Q0 is only used to balance the small flow caused by internal leakage, and the pressure P at the output end of the power pump 1 is maintained at the working pressure Pd and no longer increases. Since the working pressure Pd is less than the opening pressure Pmax of the overflow valve 3, it is ensured that the overflow valve 3 does not overflow during this process, avoiding the overflow valve 3 from being stuck and causing overflow loss.

[0055] The preset position Lb and the preset acceleration can be calculated according to actual conditions, and are mainly related to the overflow pressure threshold of the overflow valve 3, the working condition of the working machine, and the selection and configuration of the cylinder 2. The preset acceleration can be a constant value or a variable value, which can be set according to actual needs.

[0056] The preset position Lb and the preset acceleration can be set in multiple manners. For example, the relief pressure threshold of the relief valve 3 is a fixed value and is necessarily greater than the maximum working pressure actually required by the working machine. However, the working conditions, heavy load, light load and other different situations of the working machine require different working pressures, so when the actuator cylinder 2 extends or retracts to the limit position, there is a difference between the relief pressure threshold and the actual working pressure value. In the difference interval, although no relief occurs, unnecessary energy loss and waste are caused. At this time, different preset positions and preset accelerations under different working conditions or loads can be set according to different differences to further reduce the energy loss under the condition of controlling no relief. Specifically, the greater the difference, the farther the preset position Lb can be set from the limit position Lmax of the actuator cylinder, that is, the longer the extension and retraction stroke of the actuator cylinder is set, so that the actuator cylinder pressure can be slowly increased to the working pressure Pd required by the actual work when reaching the limit position Lmax. Alternatively, the preset flow acceleration can be set to be greater, that is, the flow is reduced faster so that the actuator cylinder pressure can be slowly increased to the working pressure Pd required by the actual work.

[0057] The power pump can be a constant flow pump, which is convenient for controlling the output flow of the power pump.

[0058] In some embodiments, the anti-relief system further comprises a pressure sensor 5. The pressure sensor 5 is arranged on the pipeline in communication with the inlet end of the relief valve 3 to detect the pressure at the inlet end of the relief valve 3. The pressure sensor 5 is in communication connection with the control module, and after detecting the pressure at the inlet end of the relief valve 3, the pressure sensor 5 can send a signal containing the pressure information at the inlet end of the relief valve 3 to the control module. The pressure at the inlet end of the relief valve 3 is the pressure at the output end of the pressure pump.

[0059] As shown in FIGS. 5 and 6, during the extension and retraction of the actuator cylinder 2 from the initial position to the limit position Lmax, the pressure sensor 5 detects the pressure at the inlet end of the relief valve 3 in real time.

[0060] When the actuator 2 is empty or the load is constant during the extension or retraction, the inlet pressure of the relief valve 3 is less than the opening pressure Pmax of the relief valve 3 before reaching the limit position Lmax. The control module can determine that the inlet pressure of the relief valve 3 is less than the opening pressure Pmax of the relief valve 3 according to the information detected by the pressure sensor 5. When the position sensor 4 detects that the actuator 2 extends or retracts to the preset position Lb under this condition, a signal is sent to the control module, so that the control module determines that the actuator 2 extends or retracts to the preset position Lb. Then the control module sends a control signal to the power pump 1 to gradually reduce the speed of the power pump 1 to reduce the output flow at a preset acceleration. In this way, during the extension or retraction of the actuator 2 from the preset position to the limit position Lmax, the output flow Q of the power pump 1 gradually decreases, and the pressure P at the output end of the power pump 1 increases at a smaller rate. When the actuator 2 extends or retracts to the limit position Lmax, the pressure P at the output end of the power pump 1 increases to Pc, the output flow of the power pump 1 decreases to a preset flow Q0, and the pressure P at the output end of the power pump 1 increases to the working pressure Pd and no longer rises as the power pump 1 continues to output flow. The preset flow Q0 is only used to balance the small flow of internal leakage and the like, and the pressure P at the output end of the power pump 1 is maintained at the working pressure Pd and no longer rises. Since the working pressure Pd is less than the opening pressure Pmax of the relief valve 3, it is ensured that the relief valve 3 does not overflow during this process, avoiding the relief valve 3 from being stuck and causing overflow loss.

[0061] When the actuator 2 suddenly adds a load at L1 during extension or retraction, the continuous output flow at the output end of the power pump 1 causes the pressure P at the output end of the power pump 1 to suddenly increase to exceed the opening pressure Pmax of the relief valve 3. The control module can determine that the inlet pressure of the relief valve 3 is not less than the opening pressure Pmax of the relief valve 3 according to the information detected by the pressure sensor 5. Under this condition, the control module controls the power pump 1 to reduce the speed to reduce the output flow, so that the pressure at the inlet of the relief valve 3 is reduced to be less than the opening pressure of the relief valve 3, thereby ending the overflow of the relief valve 3 as soon as possible, reducing the overflow time of the relief valve 3, and avoiding the increase of the probability of the relief valve 3 being stuck and the increase of the overflow loss due to the long overflow time of the relief valve 3. Until the actuator 2 extends or retracts to the limit position Lmax, the output flow of the power pump 1 decreases to a small flow only for balancing the internal leakage and the like, at which time the pressure at the output end of the power pump 1 decreases to the working pressure Pd required for maintaining the actuator 2 at the limit position Lmax and no longer rises. It is ensured that the relief valve 3 does not overflow during this process, avoiding the relief valve 3 from being stuck and causing overflow loss.

[0062] It is worth noting that if L1 is located before Lb, even if the control module controls the power pump 1 to reduce the speed to reduce the output flow, so that the pressure at the inlet of the relief valve 3 is reduced to be less than the opening pressure of the relief valve 3, the control module no longer determines that the actuator 2 extends or retracts to the preset position Lb.

[0063] In further embodiments, as shown in Fig. 1, the anti-flowing system further comprises a pressure relief flow path, one end of the pressure relief flow path is in communication with the output end of the power pump 1, and the other end of the pressure relief flow path is in communication with the oil tank 9. An electromagnetic valve 6 is arranged in the pressure relief flow path, and the control module is in communication connection with the electromagnetic valve 6. Thus, the control module can control the electromagnetic valve 6 to open or close.

[0064] As shown in Fig. 5, under the condition that the control module judges that the pressure P at the inlet end of the overflow valve 3 is not less than the opening pressure Pmax of the overflow valve 3 and controls the output flow rate Q of the power pump 1 to decrease, when the control module determines according to the signals detected and sent by the pressure sensor 5 that the pressure at the inlet end of the overflow valve 3 does not change or continues to increase, the control module controls the electromagnetic valve 6 to open. Part of the flow rate output by the power pump 1 is discharged to the oil tank 9 through the pressure relief flow path, so as to reduce the pressure at the output end of the power pump 1 to be less than the opening pressure of the overflow valve 3 until the working pressure Pd is reached. The overflowing of the overflow valve 3 is ended as soon as possible, the overflowing time of the overflow valve 3 is reduced, and the probability of sticking and the increase of overflowing loss caused by long overflowing time of the overflow valve 3 are avoided.

[0065] When the control module determines according to the signals detected and sent by the pressure sensor 5 that the pressure at the inlet end of the overflow valve 3 is greater than the working pressure Pd, the control module can control the electromagnetic valve 6 to open. Part of the flow rate output by the power pump 1 is discharged to the oil tank 9 through the pressure relief flow path, so as to reduce the pressure at the output end of the power pump 1 to be less than the opening pressure of the overflow valve 3 until the working pressure Pd is reached.

[0066] When the control module controls the electromagnetic valve 6 to open, it should be ensured that the user does not actively increase or maintain the rotation speed of the power pump 1 to increase or maintain the output flow rate. That is, under the premise that the user actively reduces the rotation speed of the power pump 1, if the power pump 1 cannot reduce the rotation speed to reduce the output flow rate, the pressure at the inlet end of the overflow valve 3 continues to increase, and then the control module controls the electromagnetic valve 6 to open.

[0067] In some embodiments, the anti-flowing system further comprises a one-way valve 7, wherein the output end of the power pump 1 is in communication with the actuator cylinder 2 through the one-way valve 7, so that the one-way valve 7 is open when the power pump 1 outputs flow rate to the actuator cylinder 2. The backflow of oil to the hydraulic pump is prevented.

[0068] In some embodiments, multiple execution cylinders 2 are provided, such as two lifting cylinders and one reversing cylinder in a loader. Each execution cylinder 2 is connected to the power pump 1 through a directional valve 8. Through the directional valve 8, the power pump 1 can drive each execution cylinder 2 to extend or retract to perform a work action. Correspondingly, multiple position sensors 4 are provided and connected to the control module, each position sensor 4 corresponds to one execution cylinder 2, and each position sensor 4 detects the extension or retraction position of the corresponding execution cylinder 2. In this way, for different execution cylinders 2, the corresponding position sensor 4 detects the position, so that the control module can control the output flow of the power pump 1 corresponding to different execution cylinders 2, to avoid overflow of the overflow valve 3.

[0069] According to the embodiments of the present application, in another aspect, a work machine is also provided, which is provided with a hydraulic system including any of the above-described anti-overflow systems. Therefore, the work machine has the advantages of the above-described anti-overflow system, which will not be repeated here.

[0070] According to the embodiments of the present application, in still another aspect, as shown in FIGS. 2-4, an anti-overflow method is also provided. The output end of the power pump 1 is connected to the execution cylinder 2, the power pump 1 is adapted to drive the execution cylinder 2 to extend or retract to perform a work action, and the inlet end of the overflow valve 3 is connected to the output end of the power pump 1.

[0071] When the execution cylinder 2 extends or retracts between the initial position and the limit position Lmax and performs a work action, the extension or retraction position of the execution cylinder 2 is determined in real time. A preset position Lb is provided between the initial position and the limit position Lmax. When the execution cylinder 2 is at the initial position, the extension or retraction amount of the execution cylinder 2 is 0, and the pressure at the output end of the power pump 1 is 0. When the power pump 1 starts to output a flow rate Qe, the execution cylinder 2 starts to extend or retract from the initial position to the limit position Lmax, and the pressure at the output end of the power pump 1 gradually increases.

[0072] When it is determined that the execution cylinder 2 extends or retracts to the preset position Lb, the control module controls the power pump 1 to gradually reduce the rotation speed at a preset acceleration to reduce the output flow rate. In this way, during the process that the execution cylinder 2 extends or retracts from the preset position to the limit position Lmax, the output flow rate Q of the power pump 1 gradually decreases, and the pressure P at the output end of the power pump 1 increases at a smaller rate. When the execution cylinder 2 extends or retracts to the limit position Lmax, the pressure P at the output end of the power pump 1 increases to Pc, the output flow rate of the power pump 1 decreases to a preset flow rate Q0, and as the power pump 1 continues to output the flow rate, the pressure P at the output end of the power pump 1 no longer increases after increasing to the working pressure Pd. The preset flow rate Q0 is only used to balance the small flow rate of internal leakage, and the pressure P at the output end of the power pump 1 is maintained at the working pressure Pd and no longer increases. Since the working pressure Pd is less than the opening pressure Pmax of the overflow valve 3, it is ensured that the overflow valve 3 will not overflow during this process, avoiding the overflow valve 3 from being stuck and causing overflow loss.

[0073] In further embodiments, the anti-overflow method further comprises: determining that the inlet pressure of the overflow valve 3 is less than the opening pressure Pmax of the overflow valve 3 or not less than the opening pressure Pmax of the overflow valve 3 during the process of extending and retracting the actuating cylinder 2 from the initial position to the limit position Lmax.

[0074] When the actuating cylinder 2 is empty or the load is constant during the extension and retraction process, the inlet pressure of the overflow valve 3 is less than the opening pressure Pmax of the overflow valve 3 before reaching the limit position Lmax. When it is determined that the actuating cylinder 2 is extended and retracted to the preset position Lb under the condition that the inlet pressure of the overflow valve 3 is less than the opening pressure Pmax of the overflow valve 3, the control power pump 1 gradually reduces the output flow by gradually reducing the speed. In this way, during the process of extending and retracting the actuating cylinder 2 from the preset position to the limit position Lmax, the output flow Q of the power pump 1 gradually decreases, and the pressure P at the output end of the power pump 1 increases at a smaller rate. When the actuating cylinder 2 is extended and retracted to the limit position Lmax, the pressure P at the output end of the power pump 1 increases to Pc, the output flow of the power pump 1 decreases to the preset flow Q0, and the pressure P at the output end of the power pump 1 increases to the working pressure Pd and no longer rises as the power pump 1 continues to output flow. The preset flow Q0 is only used to balance the small flow caused by internal leakage, and the pressure P at the output end of the power pump 1 is maintained at the working pressure Pd and no longer rises. Since the working pressure Pd is less than the opening pressure Pmax of the overflow valve 3, it is ensured that the overflow valve 3 will not overflow during this process, avoiding the overflow valve 3 from being stuck and causing overflow loss.

[0075] When the actuating cylinder 2 suddenly adds a load at L1 during the extension and retraction process, the continuous output flow at the output end of the power pump 1 causes the pressure P at the output end of the power pump 1 to suddenly increase to exceed the opening pressure Pmax of the overflow valve 3. Under the condition that the inlet pressure of the overflow valve 3 is not less than the opening pressure Pmax of the overflow valve 3, the control power pump 1 reduces the output flow by gradually reducing the speed, so that the pressure at the inlet of the overflow valve 3 decreases to less than the opening pressure of the overflow valve 3, thereby ending the overflow of the overflow valve 3 as soon as possible, reducing the overflow time of the overflow valve 3, and avoiding the increase of the probability of the overflow valve 3 being stuck and the increase of the overflow loss due to the long overflow time of the overflow valve 3. Until the actuating cylinder 2 is extended and retracted to the limit position Lmax, the output flow of the power pump 1 decreases to a small flow only used to balance the internal leakage, and at this time the pressure at the output end of the power pump 1 decreases to the working pressure Pd required to maintain the actuating cylinder 2 at the limit position Lmax and no longer rises. It is ensured that the overflow valve 3 will not overflow during this process, avoiding the overflow valve 3 from being stuck and causing overflow loss.

[0076] It is worth noting that if L1 is located before Lb, even if the control power pump 1 reduces the output flow by gradually reducing the speed, so that the pressure at the inlet of the overflow valve 3 decreases to less than the opening pressure of the overflow valve 3, it is no longer determined that the actuating cylinder 2 is extended and retracted to the preset position Lb.

[0077] In a further embodiment, as shown in Fig. 5, under the condition that the pressure at the inlet of the overflow valve 3 is determined not to be less than the opening pressure Pmax of the overflow valve 3 and the output flow rate Q of the power pump 1 is controlled to decrease, when the pressure at the inlet of the overflow valve 3 is determined to be constant or continue to increase, the power pump 1 is controlled to be relieved, so as to reduce the pressure at the outlet of the power pump 1 to be less than the opening pressure of the overflow valve 3 until the working pressure Pd is reached. The overflow of the overflow valve 3 is ended as soon as possible, the overflow time of the overflow valve 3 is reduced, and the probability of jamming and the increase of overflow loss caused by the long overflow time of the overflow valve 3 are avoided.

[0078] When the pressure at the inlet of the overflow valve 3 is determined to be greater than the working pressure Pd, the electromagnetic valve 6 is controlled to be opened. Part of the output flow of the power pump 1 is discharged to the tank 9 through the relief flow path, so as to reduce the pressure at the outlet of the power pump 1 to be less than the opening pressure of the overflow valve 3 until the working pressure Pd is reached.

[0079] In some embodiments, the anti-overflow method further comprises: determining that the actuator cylinder 2 is extended and retracted from the initial position to the limit position, and determining that the actuator cylinder 2 is extended and retracted to the working position, and controlling the power pump 1 to reduce the output flow rate so that the pressure of the overflow valve 3 is less than the overflow pressure, thereby ending the overflow of the overflow valve 3 more quickly, reducing the overflow time of the overflow valve 3, and avoiding the increase of the probability of jamming and the increase of the overflow loss caused by the long overflow time of the overflow valve 3.

[0080] Specifically, based on the statistical determination of the AI large model, under a certain working condition, after the actuator cylinder 2 is extended and retracted to a certain position and starts to bear load, the extension and retraction position of the actuator cylinder 2 at this time is the working position under the working condition. When the actuator cylinder 2 starts to bear load, the pressure at the outlet of the power pump 1 will increase sharply. When the actual working condition is located in the working condition, when the actuator cylinder 2 is extended and retracted from the initial position to the limit position, and it is determined that the actuator cylinder 2 is extended and retracted to the working position, the speed of the power pump 1 is immediately controlled to be reduced to reduce the output flow rate, so that the increasing speed of the pressure at the outlet of the power pump 1 is slowed down, so that the pressure at the outlet of the power pump 1 cannot increase to exceed the opening pressure of the overflow valve 3, or the pressure at the outlet of the power pump 1 exceeds the opening pressure of the overflow valve 3 for a short time and then drops below the opening pressure of the overflow valve 3, thereby ending the overflow of the overflow valve 3 more quickly, reducing the overflow time of the overflow valve 3, and avoiding the increase of the probability of jamming and the increase of the overflow loss caused by the long overflow time of the overflow valve 3.

[0081] It is worth noting that the corresponding working positions under multiple working conditions can be counted, and control is performed under a certain working condition with the corresponding working position under the working condition.

[0082] Although the embodiments of the present application have been described with reference to the accompanying drawings, it will be understood that various modifications and changes can be made by those skilled in the art without departing from the spirit and scope of the present application, and such modifications and changes are intended to fall within the scope of the present application.

Claims

1. An anti-overflow system, comprising: an actuating cylinder (2) adapted to extend and retract to perform an operation action; a power pump (1) having an output end in communication with the actuating cylinder (2), the power pump (1) being adapted to drive the actuating cylinder (2) to extend and retract; an overflow valve (3) having an inlet end in communication with the output end of the power pump (1); a position sensor (4) adapted to detect the extension and retraction position of the actuating cylinder (2); a control module in communication with the power pump (1) and the position sensor (4), the control module being adapted to determine, when the actuating cylinder (2) extends and retracts to a preset position, to control the power pump (1) to gradually reduce the rotation speed at a preset acceleration to reduce the output flow, until the actuating cylinder (2) extends and retracts to a limit position, the output flow of the power pump (1) is reduced to a preset flow; wherein, under the condition of the preset flow, the pressure at the output end of the power pump (1) is less than the opening pressure of the overflow valve (3).

2. The anti-overflow system according to claim 1, further comprising: a pressure sensor (5) in communication with the control module, the pressure sensor (5) being adapted to detect the pressure at the inlet end of the overflow valve (3); wherein: the control module is adapted to determine, when the pressure at the inlet end of the overflow valve (3) is less than the opening pressure of the overflow valve (3) and the actuating cylinder (2) extends and retracts to a preset position, to control the power pump (1) to gradually reduce the rotation speed at the preset acceleration to reduce the output flow, until the actuating cylinder (2) extends and retracts to a limit position, the output flow of the power pump (1) is reduced to the preset flow; the control module is further adapted to determine, when the pressure at the inlet end of the overflow valve (3) is not less than the opening pressure of the overflow valve, to control the power pump (1) to reduce the rotation speed to reduce the output flow, so that the pressure at the inlet end of the overflow valve is less than the opening pressure of the overflow valve.

3. The anti-overflow system according to claim 2, further comprising: a pressure relief flow path in communication with the output end of the power pump (1), the pressure relief flow path being provided with a solenoid valve (6), the control module being in communication with the solenoid valve (6), the control module being adapted to, after the power pump (1) is controlled to reduce the rotation speed to reduce the output flow when the pressure at the inlet end of the overflow valve (3) is not less than the opening pressure of the overflow valve (3), determine that the pressure at the inlet end of the overflow valve (3) is unchanged or continues to increase, and control the power pump (1) to relieve pressure.

4. The anti-overflow system according to claim 3, further comprising: a check valve (7), the output end of the power pump (1) being in communication with the actuating cylinder (2) through the check valve (7), the check valve (7) being adapted to be one-way conductive when the power pump (1) outputs flow to the actuating cylinder (2). a plurality of the actuating cylinders (2) are provided and respectively in communication with the power pump (1), a plurality of the position sensors (4) are provided and respectively in communication with the control module, each of the position sensors (4) being adapted to correspondingly detect the extension and retraction position of one of the actuating cylinders (2).

5. The anti-overflow system according to any one of claims 1 to 4, wherein, ​ 6. A working machine provided with a hydraulic system comprising the anti- spill system according to any one of claims 1-5.

7. An anti-spill method, a power pump (1) is in communication with an actuator cylinder (2), the power pump (1) is adapted to drive the actuator cylinder (2) to extend or retract to perform a working action, a spill valve (3) is in communication with the power pump (1), the anti-spill method comprising: determining when the actuator cylinder (2) extends or retracts to a preset position, controlling the power pump (1) to gradually reduce the speed at a preset acceleration to reduce the output flow, until the actuator cylinder (2) extends or retracts to an extreme position, the output flow of the power pump (1) is reduced to a preset flow; wherein under the condition of the preset flow, the pressure at the output end of the power pump (1) is less than the opening pressure of the spill valve (3).

8. The anti-spill method according to claim 7, further comprising: determining when the pressure at the inlet end of the spill valve (3) is less than the opening pressure of the spill valve (3), and the actuator cylinder (2) extends or retracts to a preset position, controlling the power pump (1) to gradually reduce the speed at the preset acceleration to reduce the output flow, until the actuator cylinder (2) extends or retracts to an extreme position, the output flow of the power pump (1) is reduced to a preset flow; determining when the pressure at the inlet end of the spill valve (3) is not less than the opening pressure of the spill valve (3), controlling the power pump (1) to reduce the speed to reduce the output flow, so that the pressure at the inlet end of the spill valve (3) is less than the spill pressure.

9. The anti-overflow method of claim 8, wherein, determining when the pressure at the inlet end of the spill valve (3) is not less than the opening pressure of the spill valve (3), controlling the power pump (1) to reduce the speed to reduce the output flow, further comprising: determining when the pressure at the inlet end of the spill valve (3) is not less than the opening pressure of the spill valve (3), controlling the power pump (1) to reduce the speed to reduce the output flow, so that the pressure at the inlet end of the spill valve (3) is less than the spill pressure.

10. The anti-spill method according to any one of claims 7-9, further comprising: determining when the actuator cylinder (2) extends or retracts from an initial position to an extreme position, and the actuator cylinder (2) extends or retracts to a working position, controlling the power pump (1) to reduce the speed to reduce the output flow, so that the pressure of the spill valve (3) is less than the spill pressure, wherein the extension or retraction position of the actuator cylinder (2) is the working position when the pressure at the inlet end of the spill valve (3) is greater than the opening pressure of the spill valve (3). ​

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