Single-stage double-acting hydraulic cylinder automatic circulation flushing system

Abstract

The present application relates to a kind of single-stage double-acting hydraulic cylinder automatic circulation flushing system, belong to hydraulic cylinder flushing technical field;Including power module, fluid control module, sensing detection module, power module includes oil source and flushing pump, fluid control module is arranged between power module and hydraulic cylinder, fluid control module includes flow direction switching unit, flow direction switching unit includes three-position four-way reversing valve, the oil inlet of three-position four-way reversing valve and oil return are connected with oil source, two working oil ports of three-position four-way reversing valve are sequentially connected with one two-position two-way reversing valve and one two-position three-way reversing valve, the oil outlet of two two-position three-way reversing valves is respectively connected with the rod cavity interface and the rod cavity interface of hydraulic cylinder, and the oil outlet of two two-position three-way valves is connected with oil source;Sensing detection module includes pressure sensor and flow sensor arranged on pipeline;Solve the problem of poor flushing effect of current single-stage double-acting hydraulic cylinder.

Description

Technical Field

[0001] This invention belongs to the field of hydraulic cylinder flushing technology, specifically relating to an automatic circulating flushing system for a single-stage double-acting hydraulic cylinder. Background Technology

[0002] Single-stage double-acting hydraulic cylinders are widely used in engineering machinery, metallurgical equipment, injection molding machines, and other fields. During long-term operation, hydraulic systems inevitably generate contaminants such as metal wear particles, seal debris, oxides, and externally infiltrated dust. Strictly controlling the cleanliness of the cylinder's internal cavity is crucial; any residual material can enter the system with the hydraulic oil, causing malfunctions. Therefore, flushing of single-stage double-acting hydraulic cylinders is necessary. However, existing flushing technologies have the following problems: (1) Because the rod chamber and rodless chamber of a single-stage double-acting hydraulic cylinder each have only one oil port, neither chamber can form an independent closed fluid circuit. Conventional circulating flushing processes (such as...) Figure 3 As shown, this method is difficult to implement and can easily result in incomplete cleaning of the internal cavity. Therefore, it is necessary to disassemble the hydraulic cylinder to the component level while the machine is stopped, and manually clean the cylinder barrel and piston and other parts using a special cleaning agent. This method is not only time-consuming and labor-intensive, requiring professional maintenance personnel and significantly increasing maintenance costs, but also allows external dust to easily enter the cylinder during disassembly and assembly, causing serious secondary pollution and even damaging precision seals.

[0003] (2) Existing online flushing functions mostly rely on the bypass filter of the main system or simple back flushing. Due to the compact structure of the single-stage double-acting hydraulic cylinder, there are tiny gaps (dead zone volume) between the piston and cylinder barrel, and at the corners of the end cap. Ordinary low-pressure flushing of the main system has a slow flow rate and insufficient impact force, making it difficult to peel off and remove stubborn contaminants (such as metal shavings and oxides) adhering to the inner wall of the cylinder barrel and the back of the sealing strip, resulting in poor cleaning effect, easy residue of contaminants and accelerated wear of the seals.

[0004] (3) Most current hydraulic systems lack intelligent condition monitoring mechanisms. Flushing operations often rely on the operator's experience or are manually started at fixed time intervals. This will lead to two extreme situations: first, when the system is severely contaminated, it is not flushed in time, resulting in premature component failure; second, when the system is relatively clean, it is still forcibly flushed at a fixed cycle, resulting in hydraulic oil waste and energy consumption. In addition, manual operation is also prone to misoperation, such as starting flushing without isolating the main oil circuit, which can cause system pressure conflicts.

[0005] (4) During forward and reverse flushing, if the pipeline design is unreasonable or the control logic is missing, the oil in the rodless chamber and the rod chamber may mix in an unexpected way, or the high-pressure flushing oil may accidentally enter the main working circuit, impacting the precision servo valve or proportional valve of the main system, causing contamination or damage to the main system. At the same time, flushing under load poses a huge mechanical safety risk. Summary of the Invention

[0006] This invention overcomes the shortcomings of the prior art and proposes an automatic circulating flushing system for a single-stage double-acting hydraulic cylinder; solving the problem of poor flushing effect of current single-stage double-acting hydraulic cylinders.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solution.

[0008] An automatic circulating flushing system for a single-stage double-acting hydraulic cylinder includes a power source module, a fluid control module, and a sensing and detection module. The power source module includes an oil source and a flushing pump. A fluid control module is located between the power source module and the hydraulic cylinder. The fluid control module includes a flow direction switching unit, which includes a three-position four-way directional valve. The inlet and outlet of the three-position four-way directional valve are both connected to the oil source. A two-position two-way directional valve and a two-position three-way directional valve are sequentially connected to the two working ports of the three-position four-way directional valve. The outlets of the two two-position three-way directional valves are respectively connected to the rod-side port and the rodless port of the hydraulic cylinder. The outlets of the two two-position three-way valves are both connected to the oil source. The sensing and detection module includes a pressure sensor and a flow sensor installed on the pipeline.

[0009] Furthermore, the inlet of the flushing pump extends into the oil source, and the outlet of the flushing pump is connected to the inlet of the three-position four-way directional valve through the first oil inlet pipeline. The oil source is connected to the return port of the three-position four-way directional valve through the main return oil pipeline.

[0010] Furthermore, the first working port of the three-position four-way directional valve is connected to the inlet port of the first two-position two-way directional valve through the second inlet pipeline, the outlet port of the first two-position two-way directional valve is connected to the inlet port of the first two-position three-way directional valve through the third inlet pipeline, and the outlet port of the first two-position three-way directional valve is connected to the rodless chamber interface of the hydraulic cylinder through the first working pipeline.

[0011] Furthermore, the second working port of the three-position four-way directional valve is connected to the inlet port of the second two-position two-way directional valve through the fourth inlet pipe, the outlet port of the second two-position two-way directional valve is connected to the inlet port of the second two-position three-way directional valve through the fifth inlet pipe, and the outlet port of the second two-position three-way directional valve is connected to the rod chamber interface of the hydraulic cylinder through the second working pipe.

[0012] Furthermore, a first return oil line is provided at the return oil port of the first two-position three-way directional valve, and a second return oil line is provided at the return oil port of the second two-position three-way directional valve. The outlet ends of the first and second return oil lines are connected to the third return oil line, and the outlet end of the third return oil line is connected to the main return oil line.

[0013] Furthermore, the fluid control module also includes a pressure regulating unit and a flow regulating unit. The pressure regulating unit adopts an electro-proportional relief valve or a servo valve, and the flow regulating unit adopts an electro-proportional flow valve or a speed regulating valve. Both the pressure regulating unit and the flow regulating unit are located on the first oil inlet pipeline.

[0014] Furthermore, a first pressure sensor is installed on the first working pipeline, and a second pressure sensor is installed on the second working pipeline.

[0015] Furthermore, a first flow sensor is installed on the first oil inlet pipe, and a second flow sensor is installed at the end of the main return oil pipe that extends into the oil source.

[0016] Furthermore, the fluid control module also includes a one-way flow unit, which includes a first one-way valve, a second one-way valve, and a third one-way valve. The first one-way valve is located on the first return oil line, the second one-way valve is located on the second return oil line, and the third one-way valve is located on the third return oil line. A second filter is also provided on the third return oil line, and the second filter is located behind the third one-way valve.

[0017] Furthermore, the sensing and detection module also includes an oil cleanliness sensor, which is installed on the main return oil line.

[0018] The beneficial effects of this invention compared to the prior art are as follows: (1) This invention utilizes an independent flushing pump to provide cleaning oil with a pressure higher than that of the main system back pressure, which can overcome the friction of the seals and realize the full-stroke reciprocating motion of the piston, ensuring that the entire inner wall of the cylinder is covered without dead corners; it introduces a high-frequency pulse / oscillation flushing mode, which utilizes the turbulence effect of the fluid and mechanical vibration to effectively loosen and peel off stubborn contaminants such as metal shavings and oxides attached to the micro-roughness of the inner wall of the cylinder and the back of the sealing strip; it significantly reduces the probability of early failure of the seals due to particle wear, and is expected to increase the average fault-free working time of the hydraulic cylinder by 20%-30%. At the same time, when repairing the hydraulic cylinder, it can replace the secondary disassembly condition, reduce maintenance costs, and improve maintenance efficiency.

[0019] (2) The present invention constructs an independent flushing oil circuit (independent pump + independent oil source), the flushing process is completely decoupled from the main working oil circuit, and the oil is set with unidirectional flow characteristics. The dirty oil only flows back to the oil tank through the filtration system after flushing, and never flows back to the main system to avoid the contaminated oil from re-entering the cylinder system and causing secondary pollution. It fundamentally eliminates the risk of secondary pollution in the flushing process and ensures the safety and accuracy of the core components of the main hydraulic system.

[0020] (3) This invention combines multiple indicators such as “cumulative running time”, “abnormal pressure difference at both ends” and “oil cleanliness sensor data” for comprehensive judgment; once the triggering conditions are met, the system automatically completes the entire process of isolation, switching, flushing and resetting without manual intervention; it realizes the transformation from “regular maintenance” to “condition monitoring + predictive maintenance”, reduces the number of ineffective flushing, saves hydraulic oil consumption by about 15%-20%, and significantly reduces on-site operation and maintenance manpower costs.

[0021] (4) The control system of the present invention has built-in safety logic. Only after confirming that the three-position four-way reversing valve is in the neutral position and the system pressure drops to the safety threshold can the flushing pump and reversing valve be started. Anti-oil cross-connection design: Through specific valve block flow channel design and electrical interlock, it is ensured that the flushing oil circuit will not be accidentally connected to the main oil supply port. It eliminates the risk of human error and ensures the dual safety of equipment maintenance and operation personnel.

[0022] (5) The flushing module of the present invention adopts a standardized interface and can be directly connected in parallel to the oil port of the existing hydraulic cylinder without making large-scale modifications to the main structure; the miniaturized flushing pump group and valve block design makes it easy to install next to equipment with limited space; the modification cost is low and the installation is convenient, and it is suitable for new equipment manufacturing, old equipment modification and upgrading, and maintenance of individual hydraulic cylinders. Attached Figure Description

[0023] The present invention will now be described in further detail with reference to the accompanying drawings: Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a flowchart of the single-stage hydraulic cylinder of the present invention during flushing; Figure 3 This is a schematic diagram of the structure of an existing single-stage double-acting hydraulic cylinder flushing system; In this system, 1 is the oil source, 2 is the hydraulic cylinder, 3 is the three-position four-way directional valve, 4 is the first oil inlet line, 5 is the main return line, 6 is the discharge line, 7 is the shut-off valve, 8 is the first filter, 9 is the second oil inlet line, 10 is the first two-position two-way directional valve, 11 is the third oil inlet line, 12 is the first two-position three-way directional valve, 13 is the first working line, 14 is the fourth oil inlet line, 15 is the second two-position two-way directional valve, and 16 is the fifth oil inlet line. 17 is the second two-position three-way directional valve, 18 is the second working pipeline, 19 is the first return oil pipeline, 20 is the second return oil pipeline, 21 is the third return oil pipeline, 22 is the electro-proportional relief valve, 23 is the one-way speed control valve, 24 is the first one-way valve, 25 is the second one-way valve, 26 is the third one-way valve, 27 is the second filter, 28 is the first pressure sensor, 29 is the second pressure sensor, 30 is the first flow sensor, and 31 is the central control module. Detailed Implementation

[0024] To make the technical problems to be solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail with reference to the embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. The technical solutions of this invention are described in detail below with reference to the embodiments and accompanying drawings, but the scope of protection is not limited thereto.

[0025] like Figure 1 As shown in Figure 2, this invention provides an automatic circulating flushing system for a single-stage double-acting hydraulic cylinder, comprising a power source module, a fluid control module, and a sensing and detection module. The power source module includes an oil source 1 and a flushing pump. A fluid control module is disposed between the power source module and the hydraulic cylinder 2. The fluid control module includes a flow direction switching unit, which includes a three-position four-way directional valve 3. The inlet and outlet of the three-position four-way directional valve 3 are both connected to the oil source 1. A two-position two-way directional valve and a two-position three-way directional valve are sequentially connected to the two working ports of the three-position four-way directional valve 3. The outlets of the two two-position three-way directional valves are respectively connected to the rod-side port and the rodless port of the hydraulic cylinder 2. The outlets of the two two-position three-way valves are both connected to the oil source 1. The sensing and detection module includes a pressure sensor and a flow sensor disposed on the pipeline.

[0026] The inlet of the flushing pump extends into the oil source 1, and the outlet of the flushing pump is connected to the inlet of the three-position four-way directional valve 3 via the first inlet oil line 4. The oil source 1 is connected to the return port of the three-position four-way directional valve 3 via the main return oil line 5. A discharge line 6 is also connected to the main return oil line 5, and the outlet end of the discharge line 6 is connected to the oil tank. A shut-off valve 7 is installed on the discharge line 6.

[0027] The power source module also includes a first filter 8, which is located at the inlet end of the first oil inlet pipe 4 and filters the oil entering the first oil inlet pipe 4.

[0028] The first working port of the three-position four-way directional valve 3 is connected to the inlet of the first two-position two-way directional valve 10 through the second inlet pipe 9. The outlet of the first two-position two-way directional valve 10 is connected to the inlet of the first two-position three-way directional valve 12 through the third inlet pipe 11. The outlet of the first two-position three-way directional valve 12 is connected to the rodless chamber interface of the hydraulic cylinder 2 through the first working pipe 13.

[0029] The second working port of the three-position four-way directional valve 3 is connected to the inlet port of the second two-position two-way directional valve 15 through the fourth inlet pipe 14. The outlet port of the second two-position two-way directional valve 15 is connected to the inlet port of the second two-position three-way directional valve 17 through the fifth inlet pipe 16. The outlet port of the second two-position three-way directional valve 17 is connected to the rod chamber interface of the hydraulic cylinder 2 through the second working pipe 18.

[0030] The first return oil line 19 is provided at the return oil port of the first two-position three-way directional valve 12, and the second return oil line 20 is provided at the return oil port of the second two-position three-way directional valve 17. The outlet ends of the first return oil line 19 and the second return oil line 20 are both connected to the third return oil line 21, and the outlet end of the third return oil line 21 is connected to the main return oil line 5.

[0031] The fluid control module also includes a pressure regulating unit, which adopts an electro-proportional relief valve 22 or a servo valve. In this embodiment, an electro-proportional relief valve 22 is adopted. The electro-proportional relief valve 22 is set on the first oil inlet pipe 4 and located on the rear side of the first oil inlet pipe 4, and is used to accurately set the flushing pressure.

[0032] The fluid control module also includes a flow regulation unit, which adopts an electro-proportional flow valve or a speed regulating valve. In this embodiment, a one-way speed regulating valve 23 is adopted. The one-way speed regulating valve 23 is set on the first oil inlet pipeline 4 and located behind the electro-proportional overflow valve 22, and is used to set the flushing flow rate.

[0033] The fluid control module also includes a unidirectional flow unit, which comprises a first check valve 24, a second check valve 25, and a third check valve 26. The first check valve 24 is located on the first return oil line 19, the second check valve 25 is located on the second return oil line 20, and the third check valve 26 is located on the third return oil line 21. A second filter 27 is also installed on the third return oil line 21, located downstream of the third check valve 26. Through the cooperation of the second filter 27 with the first check valve 24, the second check valve 25, and the third check valve 26, contaminants are ensured to flow only in one direction before entering the oil source 1 after passing through the high-precision second filter 27, preventing backflow.

[0034] A first pressure sensor 28 is installed on the first working pipeline 13 to detect the oil pressure at the rodless chamber interface of the hydraulic cylinder 2. A second pressure sensor 29 is installed on the second working pipeline 18 to detect the oil pressure at the rod chamber interface of the hydraulic cylinder 2. A first flow sensor 30 is installed on the first inlet pipeline 4, located behind the one-way speed control valve 23, to detect the oil flow rate output from the first inlet pipeline 4. A second flow sensor is also installed at the end of the main return pipeline 5 that extends into the oil source 1 to detect the oil flow rate returning to the oil source 1 from the main return pipeline 5.

[0035] The sensing and detection module also includes an oil cleanliness sensor, which is installed on the main return oil line 5 and is used to detect the cleanliness of the oil flowing back inside the main return oil line 5.

[0036] The system also includes a central control module 31, which includes a PLC or a microprocessor and is connected to the fluid control module and the sensing and detection module respectively. The central control module 31 is used to execute the flushing algorithm, collect data and issue control commands.

[0037] The working principle of this invention is as follows: First, the YA1 of the three-position four-way directional valve 3 is energized. The first two-position two-way directional valve 10, the second two-position two-way directional valve 15, the first two-position three-way directional valve 12, and the second two-position three-way directional valve 17 are not energized. At this time, the first oil inlet line 4 is connected to the second oil inlet line 9, the second oil inlet line 9 is connected to the third oil inlet line 11, the third oil inlet line 11 is connected to the first working line 13, and the first working line 13 is isolated from the first return line 19. The main return line 5 is connected to the fourth oil inlet line 14, the fourth oil inlet line 14 is connected to the fifth oil inlet line 16, the fifth oil inlet line 16 is isolated from the second working line 18, and the second working line 18 is connected to the second return line 20.

[0038] Under the action of the flushing pump, the oil in oil source 1 passes through the first oil inlet pipe 4, the three-position four-way reversing valve 3, the second oil inlet pipe 9, the first two-position two-way reversing valve 10, the third oil inlet pipe 11, the first two-position three-way reversing valve 12, and the first working pipe 13 in sequence before entering the rodless chamber of the hydraulic cylinder 2. This causes the piston rod of the hydraulic cylinder 2 to gradually extend outward, reducing the volume of the rod chamber of the hydraulic cylinder 2 and squeezing out the oil inside the rod chamber of the hydraulic cylinder 2. The squeezed-out oil then flows back to oil source 1 through the second working pipe 18, the second two-position three-way reversing valve 17, the second return oil pipe 20, the third return oil pipe 21, and the main return oil pipe 5 in sequence.

[0039] During the piston rod extension process, the first pressure sensor 28 collects the rodless chamber pressure data of the hydraulic cylinder 2. When the collected rodless chamber pressure value changes abruptly and exceeds a certain critical value, the control system automatically controls the YA2 of the three-position four-way directional valve 3, the first two-position three-way directional valve 12, and the second two-position three-way directional valve 17 to be energized, while the first two-position two-way directional valve 10 and the second two-position two-way directional valve 15 are not energized. At this time, the first oil inlet line 4 is connected to the fourth oil inlet line 14, the fourth oil inlet line 14 is connected to the fifth oil inlet line 16, the fifth oil inlet line 16 is connected to the second working line 18, and the second working line 18 is isolated from the second return oil line 20; the main return oil line 5 is connected to the second oil inlet line 9, the second oil inlet line 9 is connected to the third oil inlet line 11, the third oil inlet line 11 is isolated from the first working line 13, and the first working line 13 is connected to the first return oil line 19.

[0040] Under the action of the flushing pump, the oil in oil source 1 flows sequentially through the first oil inlet pipe 4, the three-position four-way reversing valve 3, the fourth oil inlet pipe 14, the second two-position two-way reversing valve 15, the fifth oil inlet pipe 16, the second two-position three-way reversing valve 17, and the second working pipe 18 into the rod chamber of the hydraulic cylinder 2. This causes the piston rod of the hydraulic cylinder 2 to gradually retract inward, reducing the volume of the rodless chamber of the hydraulic cylinder 2. This squeezes out the contaminated oil after flushing the rodless chamber. The squeezed-out oil flows sequentially through the first working pipe 13, the second two-position three-way reversing valve 17, the first return oil pipe 19, the third return oil pipe 21, and the main return oil pipe 5 back to oil source 1.

[0041] After the piston rod retracts, the pressure data of the rod chamber of the hydraulic cylinder 2 is detected by the second pressure sensor 29. When the collected rod chamber pressure value changes abruptly and exceeds a certain critical value, the control system automatically controls the YA1 of the three-position four-way directional valve 3 to be energized, while the first two-position two-way directional valve 10, the second two-position two-way directional valve 15, the first two-position three-way directional valve 12, and the second two-position three-way directional valve 17 are de-energized, and the flushing is completed in this cycle.

[0042] The flow of oil in the circulating flushing system is controlled by two two-position two-way directional valves to open and close the circulating flushing. Two two-position three-way directional valves are used to switch the oil inlet and outlet of the rod chamber and rodless chamber of the hydraulic cylinder 2. Three check valves are used to ensure that the contaminated old oil after circulating flushing flows out of the rod chamber or rodless chamber of the hydraulic cylinder 2 and then flows back to the oil source 1 after passing through the second filter 27. During the cyclic flushing process, the pressure at the inlet and outlet of the hydraulic cylinder 2, fed back by the first pressure sensor 28 and the second pressure sensor 29, is transmitted to the control system to control the directional valve to switch directions. The pressure and flow rate of the cyclic flushing are regulated by setting the electro-proportional relief valve 22 and the one-way speed control valve 23. The actual operating conditions are collected by the flow sensor, the first pressure sensor 28, and the second pressure sensor 29, and the measured data are recorded. The control system applies a PWM signal to the three-position four-way directional valve 3 to achieve alternating energization of YA1 and YA2. The operating time of the hydraulic cylinder 2 is controlled by adjusting the PWM signal period and duty cycle. During the test, the oil flowing back to the oil source 1 is collected and analyzed to monitor and analyze the cyclic flushing process.

[0043] The present invention also provides an automatic circulating flushing method, based on the above-mentioned single-stage double-acting hydraulic cylinder automatic circulating flushing system, comprising the following steps: Step 1: System Initialization and Security Self-Check The control system reads the initial state of each sensor, confirms that hydraulic cylinder 2 is stationary, the three-position four-way directional valve 3 is in the neutral position, and checks the sealing of each oil circuit and the status of each filter. If everything is normal, it enters standby mode.

[0044] Step 2, Parameter Setting and Startup The flushing parameters are preset according to the specifications and degree of contamination of the hydraulic cylinder 2 to be flushed, including: Flushing pressure (P) set — Set to 30%-60% of the rated pressure to avoid damaging the seals; Flushing flow rate (Q) set — Set to 50%-80% of the rated flow rate to avoid safety accidents caused by excessive speed; Rinse mode—Select "Continuous reciprocating mode" or "High-frequency pulse oscillation mode"; Setting the target duration or target cleanliness level; Start the power source module and preheat the oil to the optimal viscosity temperature.

[0045] Step 3, Forward Circulation Flushing Phase The control system outputs a control signal to drive the flow direction switching unit so that the oil enters the rodless chamber of the hydraulic cylinder 2 and flows out from the rod chamber of the hydraulic cylinder 2, thereby flushing the inside of the rodless chamber of the hydraulic cylinder 2.

[0046] If "continuous reciprocating mode" is selected in step two, the electro-proportional flow valve will maintain a constant flow until the piston rod of hydraulic cylinder 2 reaches the end of its stroke.

[0047] If the "high-frequency pulse oscillation mode" is selected in step two, the control will alternately energize the three-position four-way reversing valve 3, the first two-position three-way reversing valve 12, and the second two-position three-way reversing valve 17 at a frequency f (e.g., 1-5Hz), so that the piston performs short-distance high-frequency reciprocating motion in the middle area of ​​the stroke, and uses the turbulence effect to peel off the attached pollutants.

[0048] Step 4, Reverse Circulation Flushing Stage The controller reverses the signal flowing to the switching unit, causing oil to enter the rod chamber of hydraulic cylinder 2 and flow out from the rodless chamber. The operation in step three is repeated to ensure that contaminants on the inner wall of the rod chamber and the surface of the piston rod of hydraulic cylinder 2 are removed.

[0049] Step 5: Real-time monitoring and dynamic adjustment During the flushing process, the pressure value P of the rodless chamber interface (port A) of the hydraulic cylinder 2 is collected in real time by the first pressure sensor 28. A The pressure value P at the rod-side port (B port) of the hydraulic cylinder 2 is collected in real time by the second pressure sensor 29. B The return oil flow rate Q to oil source 1 is collected in real time by a second flow sensor. out .

[0050] Then, differential pressure analysis is performed, that is, the differential pressure between the rodless cavity interface (port A) and the rod cavity interface (port B) is calculated, and the differential pressure ΔP = |P| A -P B If the pressure difference ΔP continuously exceeds the set threshold, it is determined to be a serious blockage or seal failure, and an alarm will be triggered immediately and the machine will be shut down.

[0051] Then, flow stability monitoring is performed, that is, the return oil flow rate Q is detected. out If the value is lower than a certain set value, it is determined that the filter is clogged, prompting the filter element to be replaced or the flushing intensity to be reduced.

[0052] If the particle count collected by the oil cleanliness sensor is higher than the initial value, it indicates that the turbidity of the return oil is high, and the current flushing stage time will be automatically extended or the pulse frequency will be increased.

[0053] Step Six: Determining the End Point of Rinsing and Ending the Process The rinsing process is considered complete if any of the following conditions are met: ① The cumulative rinsing time has reached the preset maximum value; ② The particle count collected by the oil cleanliness sensor is lower than the preset standard; ③ When the pressure difference ΔP remains stable at an extremely low level and the flow rate recovers smoothly, it indicates that the flow channel is unobstructed.

[0054] The control system cuts off the power source, closes all solenoid valves, and resets the system.

[0055] Step 7: Data Archiving and Analysis Save the pressure curve, flow curve, and abnormal event log of this flushing, and generate a maintenance report for reference in subsequent fault diagnosis.

[0056] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. An automatic circulating flushing system with a single-stage double-acting hydraulic cylinder, characterized in that: The system includes a power source module, a fluid control module, and a sensor detection module. The power source module includes an oil source (1) and a flushing pump. A fluid control module is provided between the power source module and the hydraulic cylinder (2). The fluid control module includes a flow direction switching unit, which includes a three-position four-way directional valve (3). The oil inlet and return port of the three-position four-way directional valve (3) are connected to the oil source (1). A two-position two-way directional valve and a two-position three-way directional valve are connected sequentially to the two working oil ports of the three-position four-way directional valve (3). The oil outlets of the two two-position three-way directional valves are connected to the rod chamber interface and the rodless chamber interface of the hydraulic cylinder (2), respectively. The oil outlets of the two two-position three-way valves are connected to the oil source (1). The sensor detection module includes a pressure sensor and a flow sensor installed on the pipeline.

2. The automatic circulating flushing system with a single-stage double-acting hydraulic cylinder according to claim 1, characterized in that: The inlet of the flushing pump extends into the oil source (1), and the outlet of the flushing pump is connected to the inlet of the three-position four-way reversing valve (3) through the first oil inlet pipeline (4). The oil source (1) is connected to the return port of the three-position four-way reversing valve (3) through the main return oil pipeline (5).

3. The automatic circulating flushing system with a single-stage double-acting hydraulic cylinder according to claim 2, characterized in that: The first working port of the three-position four-way directional valve (3) is connected to the inlet of the first two-position two-way directional valve (10) through the second inlet pipeline (9). The outlet of the first two-position two-way directional valve (10) is connected to the inlet of the first two-position three-way directional valve (12) through the third inlet pipeline (11). The outlet of the first two-position three-way directional valve (12) is connected to the rodless chamber interface of the hydraulic cylinder (2) through the first working pipeline (13).

4. The automatic circulating flushing system with a single-stage double-acting hydraulic cylinder according to claim 3, characterized in that: The second working port of the three-position four-way directional valve (3) is connected to the inlet of the second two-position two-way directional valve (15) through the fourth inlet pipeline (14). The outlet of the second two-position two-way directional valve (15) is connected to the inlet of the second two-position three-way directional valve (17) through the fifth inlet pipeline (16). The outlet of the second two-position three-way directional valve (17) is connected to the rod chamber interface of the hydraulic cylinder (2) through the second working pipeline (18).

5. The automatic circulating flushing system with a single-stage double-acting hydraulic cylinder according to claim 2, characterized in that: The first return oil line (19) is provided at the return oil port of the first two-position three-way directional valve (12), and the second return oil line (20) is provided at the return oil port of the second two-position three-way directional valve (17). The outlet ends of the first return oil line (19) and the second return oil line (20) are connected to the third return oil line (21), and the outlet end of the third return oil line (21) is connected to the main return oil line (5).

6. The automatic circulating flushing system with a single-stage double-acting hydraulic cylinder according to claim 2, characterized in that: The fluid control module also includes a pressure regulating unit and a flow regulating unit. The pressure regulating unit adopts an electro-proportional relief valve (22) or a servo valve, and the flow regulating unit adopts an electro-proportional flow valve or a speed regulating valve. Both the pressure regulating unit and the flow regulating unit are located on the first oil inlet pipeline (4).

7. The automatic circulating flushing system with a single-stage double-acting hydraulic cylinder according to claim 4, characterized in that: A first pressure sensor (28) is installed on the first working pipeline (13), and a second pressure sensor (29) is installed on the second working pipeline (18).

8. The automatic circulating flushing system with a single-stage double-acting hydraulic cylinder according to claim 2, characterized in that: A first flow sensor (30) is installed on the first oil inlet pipeline (4), and a second flow sensor is also installed at the end of the main return oil pipeline (5) that extends into the oil source (1).

9. The automatic circulating flushing system with a single-stage double-acting hydraulic cylinder according to claim 5, characterized in that: The fluid control module further includes a one-way flow unit, which includes a first one-way valve (24), a second one-way valve (25), and a third one-way valve (26). The first one-way valve (24) is located on the first return oil line (19), the second one-way valve (25) is located on the second return oil line (20), and the third one-way valve (26) is located on the third return oil line (21). A second filter (27) is also provided on the third return oil line (21), and the second filter (27) is located behind the third one-way valve (26).

10. The automatic circulating flushing system with a single-stage double-acting hydraulic cylinder according to claim 2, characterized in that: The sensing and detection module also includes an oil cleanliness sensor, which is installed on the main return oil pipeline (5).

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